Angiotensin II is retained in gonadotrophs of pituitary cell aggregates cultured in serum-free medium but does not mimic the effects of exogenous angiotensins and luteinizing-hormone-releasing hormone on growth hormone release.

Angiotensin II (AII)-like immunoreactivity (LIR) was detected by immunostaining in 7.5 +/- 1.1% of cells obtained by redispersion of pituitary cell aggregates from 15- to 20-day-old female rats, cultured for 5-7 days in serum-free medium supplemented with thyroid hormone and dexamethasone. Also, renin-LIR was retained in these cultures. As shown by double immunostaining of paraffin-embedded sections of the aggregates, this AII-LIR was localized only in gonadotrophs. AII-LIR was detected at least up to 5 weeks in culture. On reversed-phase, high-performance liquid chromatography (HPLC), this AII-LIR co-migrated with authentic AII. In perifused aggregate cell cultures of 15- to 20-day-old female rat pituitary maintained in serum-free medium supplemented with dexamethasone (DEX) and triiodothyronine (T3), AII stimulated GH release. AI and AIII had a similar effect. To evaluate the possible involvement of endogenous AII in the local regulation of GH release, gonadotrophs were stimulated with luteinizing hormone-releasing hormone (LHRH). LHRH displayed a transient inhibitory effect on GH release, which was followed by a rebound of GH release after withdrawal of the peptide. Treatment of aggregates with pertussis toxin reversed this inhibitory effect into a significant stimulation of GH release. In aggregates cultured in serum-supplemented medium, LHRH provoked a significant stimulation of GH release which was still followed by a post-stimulus rebound release. In hemipituitaries from 5-day-old rats, a significant stimulatory effect of LHRH on GH release was found without rebound secretion. To evaluate the possible involvement of endogenous AII in the effects of LHRH on GH release, the influence of (Sar1,Ala8)AII, a peptide AII receptor antagonist, and of DUP753, a non-peptide AII receptor blocker was tested in various in vitro conditions. The effect of LHRH on GH release in aggregates cultured either in serum-free medium supplemented with DEX and T3 or in serum-supplemented medium was not affected by (Sar1,Ala8)AII, not even after enhancing the LHRH-induced GH release by treatment of the aggregates with pertussis toxin. A hundred times lower concentration of (Sar1,Ala8)AII, however, abolished the AII-induced changes in GH release. Also DUP753 (10 microM) failed to block LHRH-induced GH release in aggregates. (Sar1,Ala8)AII also failed to block the effect of LHRH on GH release from hemipituitaries. It is concluded that LHRH has inhibitory and stimulatory effects on GH release in cultured pituitary cell aggregates.(ABSTRACT TRUNCATED AT 400 WORDS)


Prolactin regulation of pro-opiomelanocortin gene expression in the arcuate nucleus of the rat hypothalamus.

It is well known that the opiate peptides, especially the pro-opiomelanocortin (POMC)-related peptide beta-endorphin, stimulate the release of prolactin (PRL) in the rat. In order to evaluate the involvement of PRL on the activity of POMC neurons in the arcuate nucleus, we have studied the effects of the injection of PRL into the third ventricle of intact and hypophysectomized rats as well as the effects of hyperprolactinemia induced by pituitary implants under the kidney capsule on POMC gene expression. The amounts of POMC mRNA in the arcuate nucleus were measured by in situ hybridization using a [35S]-labelled cDNA probe encoding for POMC. Hypophysectomy performed 2 weeks previously decreased by 24% the number of silver grains/unit of surface of labelled neurons. Intracerebroventricular injection of 3 micrograms of PRL 4 h before sacrifice induced a significant decrease in the hybridization signal of 32 and 20% in the intact and hypophysectomized rat, respectively. Hyperprolactinemia achieved by pituitary implants also led to a significant decrease in POMC mRNA levels. The present data show that hypophysectomy depresses hypothalamic POMC mRNA levels and that this effect is not related to the suppression of PRL secretion since this hormone exerts an inhibitory action on POMC gene expression. They suggest that the regulation of PRL secretion by short loop feedback mechanism might be well mediated by beta-endorphin which has already been shown to inhibit dopaminergic neuron activity in the arcuate nucleus.


Mutually antagonistic effects of corticosterone and prolactin on rat lymphocyte proliferation.

The present study was designed to evaluate the immunological outcome resulting from experimental conditions involving different corticosterone and prolactin ratios in rats. One set of experiments was conducted to assess the effects of prolactin and corticosterone on the in vitro mitogen-induced proliferation of spleen lymphocytes from animals previously submitted to the manipulation of their glucocorticoid status throughout adrenalectomy (ADX) and/or exposure to acute stress. The results indicated that prolactin (5 x 10(-9) M) induced a significant increase in concanavalin A- (ConA) induced proliferation of splenocytes only from ADX-control, unstressed, rats. However, a lower dose of prolactin (10(-9) M) failed to influence lymphoproliferation. Corticosterone (2 x 10(-8) and 10(-7) M) induced a dose-dependent reduction in lymphocyte proliferation in all experimental groups. Further experiments were conducted to study the relative potency of prolactin to antagonize the in vitro corticosterone-induced suppression of ConA-stimulated lymphocytes. The results showed, on the one hand, that higher doses of prolactin (10(-8) and 5 x 10(-8) M) were effective in stimulating ConA-induced lymphocyte proliferation in control, undisturbed, rats. They also showed that when prolactin and corticosterone are simultaneously added to the cultures, the immunostimulatory effect induced by a dose of 10(-8) M of prolactin can either predominate over a weak suppressive action of corticosterone (2 x 10(-8) M) or totally antagonize to normal values a marked immunosuppression induced by a higher dose of corticosterone (10(-7) M). These data support the view that different ratios between prolactin and corticosterone concentrations can result in differential immunological outcome.(ABSTRACT TRUNCATED AT 250 WORDS)


Dexamethasone and aldosterone modulate corticotropin-releasing factor-41 release from cultured rat fetal hypothalamic cells through type II and type I corticosteroid receptors respectively.

Dexamethasone and aldosterone inhibit hypothalamic corticotropin releasing factor-41 (CRF) release. The possible receptors through which these adrenal steroids affect CRF release were studied using rat fetal hypothalamic cell cultures. Neither the antimineralocorticoid RU 28318 nor the antiglucocorticoid RU 38486 alone had any effect on forskolin-stimulated CRF release. RU 38486 and RU 28318 however suppressed dexamethasone (1 microM)- and aldosterone (1 microM)-induced inhibition of forskolin (20 microM)-stimulated CRF release, respectively, suggesting that dexamethasone and aldosterone reduce CRF release through type II and type I corticosteroid receptors, respectively. RU 38486 had no effect on aldosterone-induced inhibition of forskolin-stimulated CRF release, nor did RU 28318 have any effect on dexamethasone-induced inhibition of forskolin-stimulated CRF release, indicating specificity of the binding of aldosterone with type I receptors, and dexamethasone with type II receptors in the hypothalamic cell cultures.


Proteolytic modification of prolactin by the female rat brain.

Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analyses we have identified immunoreactive prolactin (PRL) proteins with molecular weights of 24 and 16 kD in the female rat brain. Because PRL target tissues have been shown to contain enzymes which, in vitro, cleave PRL into a 16-kD PRL fragment, studies were performed to characterize PRL proteolysis in the female rat brain. In vitro proteolysis of PRL was examined by incubating [125]I-PRL with 25,000 g subcellular fractions followed by SDS-PAGE under reducing conditions. At acidic pHs, incubation of PRL with 25,000 g hypothalamic fractions consistently resulted in the generation of a 16-kD fragment. The generation of the 16-kD fragment was time and tissue concentration dependent. Enzyme inhibitor analysis indicated that PRL proteolysis could be blocked by aspartate and serine protease inhibitors, but not sulfhydryl, metalloenzyme or trypsin protease inhibitors. Subcellular localization of hypothalamic PRL proteolytic activity by equilibrium density centrifugation revealed a bimodal distribution of proteolytic activity with modal densities of 1.12 and 1.24 g/ml. Homogenization of the tissue in a hypo-osmotic medium disrupted the high density peak resulting in a single low-density peak at the top of the gradient. These data indicate that subcellular fractions of the rat brain contain enzymes which can cleave PRL into a 16-kD fragment under acidic conditions. The majority of the enzymatic activity is localized in membrane-bound particles with a density similar to subcellular particles which contain PRL.


Effects of repeated electroconvulsive shock on serotonin1A receptor binding and receptor-mediated hypothermia in the rat.

Chronic treatment with electroconvulsive shock or antidepressant drugs has been reported to attenuate the hypothermia induced by 8-hydroxy-2-(di-n-propyl)aminotetralin (8-OH-DPAT), a serotonin1A receptor agonist. In the present study, the binding of [3H]8-OH-DPAT to serotonin1A receptors was assessed after treatment of rats with electroconvulsive shock. The effect of electroconvulsive shock on 8-OH-DPAT-induced hypothermia also was evaluated. Male rats were handled or received electroconvulsive shock for either 1 or 10 days and were killed 2 days later. Ten days of electroconvulsive shock decreased beta-adrenergic receptor binding in the cerebral cortex, as previously reported. However, the binding of [3H]8-OH-DPAT to serotonin1A receptors in the cortex or hippocampus was not affected by repeated electroconvulsive shock. In the hypothalamus, 10 days (but not 1 day) of electroconvulsive shock significantly decreased the binding of [3H]8-OH-DPAT. In addition, 10 days of electroconvulsive shock resulted in an attenuation of the hypothermic response to 8-OH-DPAT, when compared to the response in handled controls. The electroconvulsive shock-induced suppression of the hypothermic response to 8-OH-DPAT was no longer evident 2 weeks after the last of 10 daily treatments. A single shock did not affect the hypothermic response to 8-OH-DPAT. The electroconvulsive shock-induced decrease in the binding of [3H]8-OH-DPAT in the hypothalamus may be related tot the electroconvulsive shock-induced attenuation of the hypothermic response to 8-OH-DPAT.


Regional analysis of 5-HT1A and 5-HT2 receptors in the fawn-hooded rat.

The Fawn-Hooded strain of rats exhibits a hemorrhagic disorder, known as platelet storage pool deficiency. In addition to the platelet dysfunction, there is an altered response to certain serotonin drugs. To assess the characteristics of the binding to 5-HT1A and 5-HT2 receptors in this strain, regions of the brain from Fawn-Hooded, Sprague-Dawley and Wistar male rats were examined. The drug [3H]8-OH-DPAT was used to label 5-HT1A receptors and the Kd values for frontal cortex, hippocampus, striatum, hypothalamus and brainstem were similar in all three strains of rat. As with the 5-HT1A receptors, no differences were observed in the Kd values for 5-HT2 receptors, in any of the regions examined, among the three strains. However, the Bmax for the binding of [3H]8-OH-DPAT in the striatum and brainstem of Fawn-Hooded rats was less than in the Sprague-Dawley and Wistar animals. Furthermore, 5-HT2 receptors displayed a greater Bmax value in the striatum and in the frontal cortex of Fawn-Hooded animals, compared to Sprague-Dawley and Wistar rats. These differences in receptors are consistent with previous studies in which Fawn-Hooded rats were found to have altered serotonergic function, relative to Wistar and Sprague-Dawley animals.


A different balance in the sensitivity of D1 and D2 dopamine receptors accounts for differences in apomorphine-induced hypothermic effects in Swiss and C3H mice.

In several strains of mice: Swiss CD1, BALB, DBA2, C57, the mixed D1/D2 direct dopamine receptor agonist, apomorphine, elicited a marked and virtually similar hypothermic effect. By contrast, in C3H mice, this effect was obviously less and shorter. Similarly, the hypothermic effects of two direct D2 dopamine agonists RU 24926 and piribedil were respectively lesser or absent in C3H, compared to Swiss CD1 mice. On the contrary, the hyperthermic effect of the D1 dopamine agonist SKF 38393 was greater in C3H than in Swiss CD1 mice. This unbalanced sensitivity of D1 and D2 dopamine receptors, involved in thermoregulation, likely accounts for the low responsiveness of C3H to the apomorphine-induced hypothermic effect.


Remoxipride and raclopride differentially alter the activity of incertohypothalamic dopaminergic neurons.

The effects of two dopaminergic (DA) antagonists, raclopride (S-(-)-3,5-dichloro-N-[(1-ethyl-2-pyrrolidinyl)methyl]-2-hydroxy- 6-methoxybenzamide(+)-tartrate) and remoxipride (S(-)-3-bromo-N-[(1-ethyl-2-pyrrolidinyl)methyl]-2, 6-dimethoxybenzamide hydrochloride monohydrate), were compared on the DA receptor-mediated regulation of incertohypothalamic and nigrostriatal DA neurons. Both drugs produced dose- and time-related increases in concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) in the striatum, which contains the terminals of the nigrostriatal DA neurons. On the other hand, raclopride but not remoxipride increased concentrations of DOPAC in the medial zona incerta and dorsomedial hypothalamic nucleus, regions that contains cell bodies and terminals, respectively, of incertohypothalamic DA neurons. These results suggest that raclopride blocks a population of DA receptors that regulates the activity of incertohypothalamic DA neurons, whereas remoxipride does not.


Dopamine receptors in the ventral pallidum regulate circling induced by opioids injected into the ventral pallidum.

Recent reports have indicated that the ventral pallidum receives enkephalinergic and dopaminergic inputs. The present study evaluated the contribution of dopamine (DA) receptors to opioid-mediated locomotor functions of the ventral pallidum. Using circling behavior as a motor index, it was determined that injection of metabolically stable analogs of enkephalin, directly into the ventral pallidum, produced a dose-dependent, naloxone-antagonizable, increase in the number of rats rotating contralateral to the injected side, as well as the rate at which the animals turned. The frequency of the contralateral rotation, induced by intra-ventral pallidal injection of DADL (which closely mimics the endogenous enkephalin peptides, exhibiting a high affinity for the delta receptor with a moderate affinity for mu receptors), increased with intraperitoneal pretreatment with amphetamine, suggesting that enhanced release of catecholamines potentiated effects of opioids in the ventral pallidum. Systemic pretreatment with the D2-preferring antagonist haloperidol, blocked the effects of DAMGO (a mu-specific agonist) but not those mediated by DADL. In contrast, the D1-specific antagonist SCH 23390 was an effective blocker of responses to both opioid peptides. Further evidence for differential consequences of activating delta or mu opioid receptors was provided by systemic pretreatment with a cholinergic antagonist; atropine attenuated responding to DADL but not to DAMGO. To ascertain if DA receptors within the ventral pallidum were sufficient to influence mu-mediated circling, it was determined that intra-ventral pallidal injection of SCH 23390 or sulpiride (a D2 specific antagonist), at concentrations that did not produce motor effects, attenuated responding to subsequent intra-ventral pallidal injections of DAMGO. Thus, the opioid receptors and DA receptors that modify responses to activation of opioid receptors are both located within the ventral pallidum. These studies point to the critical role of DA in the ventral pallidum in motor behavior induced by stimulation of opioid receptors in the ventral pallidum.


Mechanisms of adaptation to the effects of ethanol on activation of phospholipase C in NG 108-15 cells.

In this study the effect of different times of exposure to ethanol (1-7 days, 100 mM) on bradykinin and GTP(S)-stimulated activation of phospholipase C in NG 108-15 cells and on the binding of [3H]bradykinin to its receptors was investigated. Ethanol attenuated both agonist and GTP-analogue-induced hydrolysis of phosphoinositides for a period of up to 4 days of treatment, while exerting no effect on binding to bradykinin receptors. However, after 7 days of exposure to ethanol, the agonist-induced activation of phospholipase C was completely resistant to the inhibitory effects of alcohol. This finding correlated to a change in the affinity of the bradykinin receptor population after 7 days of treatment. The results indicate that bradykinin-induced breakdown of phosphatidylinositol 4,5-bisphosphate adapts to the effects of ethanol, after long-term treatment. Possible adaptative changes taking place at the level of the G protein(s), may induce a shift in the affinity of the receptor population and, consequently, serve as a compensatory mechanism to counteract the inhibitory effect of ethanol.


Influence of flunarizine, nicardipine and nimodipine on the anticonvulsant activity of different antiepileptic drugs in mice.

Only flunarizine (40 mg/kg, i.p.) significantly raised the threshold for electroconvulsions in mice (ear-clip electrodes, 0.2 sec stimulus duration, tonic hindlimb extension as an endpoint), whilst nicardipine and nimodipine (up to 80 mg/kg) was ineffective in this respect. Further, flunarizine (10 and 20 mg/kg) potentiated the efficacy of carbamazepine and valproate against maximum electroshock (50 mA)-induced seizures and, in the dose of 20 mg/kg, enhanced that of diphenylhydantoin. In addition, this calcium channel inhibitor was without influence upon the total levels of these antiepileptics in plasma. Nicardipine (5 and 10 mg/kg) and nimodipine (10 and 20 mg/kg) increased the protective potential of carbamazepine and nimodipine (20 mg/kg) also decreased the ED50 of diphenylhydantoin against maximum electroshock. However, nicardipine distinctly increased the level of carbamazepine in plasma, whilst nimodipine did not affect the level of both antiepileptics in plasma. The combined treatment of calcium channel inhibitors and antiepileptic drugs, providing a 50% protection against maximum electroshock, did not significantly change the motor performance of mice in the chimney test, when compared with antiepileptic drugs, given alone at their ED50s, against maximum electroshock-induced convulsions. The present results give further support to the idea of the combined use of some calcium channel inhibitors and antiepileptic drugs in the treatment of human epilepsy.


Verapamil and flunarizine inhibit phencyclidine-induced effects: an EEG and behavioural study in rats.

The influence of verapamil and flunarizine on phencyclidine-induced effects has been studied in adult male rats. Both verapamil (25 and 100 micrograms/10 microliters, i.c.v.) and flunarizine (40 and 60 mg/kg, i.p.) significantly reduced behavioural (mean intensity of ataxia, mean duration of head weaving) and the EEG (increase in the mean voltage of background activity of the EEG) effects induced by phencyclidine 5 mg/kg (i.p.). It was reported previously that nimodipine and diltiazem significantly potentiate effects induced by phencyclidine. The contrasting results obtained with verapamil and flunarizine, suggest that these drugs may modulate effects induced by phencyclidine by acting at sites other than NMDA receptor-coupled "L"-type calcium channel.


Effects of cholinergic agonists on regional brain energy metabolism in the scopolamine-treated rat.

The effects of scopolamine, physostigmine, RS86 and U-80816B on regional energy metabolism were studied in rodents by means of the 2-deoxyglucose autoradiographic technique. Scopolamine depressed metabolism in an area of cerebral cortex, focused around the parietal region. Rats treated with cholinergic direct agonists (U-80816B, RS86) as well as with the indirect agonist (physostigmine) all showed decreases in cortical energy metabolism, similar to scopolamine. They also induced an increase in thalamic metabolism. When these drugs were given in conjunction with scopolamine, metabolism tended to change in the opposite direction from the values obtained with the drug alone. These results suggest that there are complex interactions between pre- and post-synaptic muscarinic receptors. Additionally, nicotinic receptors could also be involved in some of the effects of physostigmine.


Neuropeptide Y immunoreactivity in the spleen and thymus of normal rats and following adjuvant-induced arthritis.

Immunoreactive neuropeptide Y (irNPY) was detected by radioimmunoassay within the rat thymus and spleen. Total spleen and thymus irNPY contents in control animals were 77 +/- 3 ng and 23 +/- 1 ng respectively (means +/- S.E.M., n = 10). Total tissue contents of irNPY 14 days following bilateral adrenalectomy or induction of inflammatory arthritis were not significantly altered compared to controls. Most spleen irNPY coeluted with synthetic NPY after reversed-phase high-performance liquid chromatography, but two peaks of irNPY were detected in thymic extracts. This suggests that NPY may be differentially expressed in tissues of the immune system.


Mutual modification of vasoactivity by calcitonin gene-related peptide and endothelin-1 in isolated porcine ophthalmic artery.

Vasodilation has been implicated in the pathophysiology of some headaches, but the mechanisms behind such abnormalities remain unknown. Calcitonin gene related peptide (CGRP), a peptide present in sensory trigeminal fibres, induces strong and long lasting vasodilation in cranial vessels, and has been found to be increased in jugular blood during migraine attacks. Endothelin (ET) is a recently identified potent vasoconstrictor peptide, which also induces long-lasting responses. ET-CGRP interactions may be of importance in vascular beds putatively involved in pain development in the head, and were therefore studied in isolated porcine ophthalmic arteries. Both peptides were found to induce strong and long-lasting reactions in this artery. CGRP decreased ET-induced contractions and ET decreased CGRP-induced relaxations. These effects were additive rather than synergistic.


Acute intragastric application of capsaicin inhibits 2-deoxy-D-glucose--but not histamine-induced gastric acid secretion in the dog.

In this study the influence of acute exposure of gastric mucosa to the sensory neurotoxin capsaicin on basal gastric acid secretion and on secretion induced by 2-deoxy-D-glucose or histamine in conscious dogs with gastric fistulae has been investigated. Under basal conditions intragastric capsaicin (160 microM, 50 ml of volume) did not induce any significant change in acid secretion and in plasma levels of gastrin. Total acid output induced by 2-deoxy-D-glucose (75 mg/kg i.v.) was significantly decreased by intragastric application of capsaicin, while plasma gastrin concentrations were unaffected. A direct stimulant of the parietal cells, such as histamine (64 micrograms/kg s.c.) increased gastric acid secretion which was not sensitive to capsaicin pretreatment. These findings indicate the involvement of capsaicin-sensitive fibers in the control of vagally-induced gastric acid secretion in the dog.


An opioid peptide inhibits capsaicin-sensitive vasodilatation in the pig's skin.

Microcirculatory effects of electrical stimulation of nerves through a pair of needle electrodes in the skin of anaesthetized pigs were studied by using the laser Doppler flowmetric method. Electrical stimulation (0.3-30 Hz) evoked a short-lasting decrease in capillary blood flux (vasoconstriction) followed by an increase (vasodilatation), of longer duration. Vasoconstriction was inhibited by local guanethidine, but not by capsaicin pretreatment, whereas vasodilatation was blocked by local capsaicin, but not by guanethidine. Both phases of the response were suppressed by local application of tetrodotoxin. Thus, vasoconstriction due to electrical stimulation seems to be of sympathetic origin, while vasodilatation is a result of a release of vasoactive substances from capsaicin-sensitive nerve endings. Vasodilatation due to electrical stimulation was strongly and dose-dependently inhibited by the opioid peptide [D-Met2,Pro5] enkephalinamide, while vasoconstriction remained apparently unchanged. At both doses of the opioid peptide tested (0.03 and 0.15 mumol/kg i.m.) inhibition of vasodilatation was larger at lower than at higher frequencies of stimulation. Guanethidine pretreatment did not influence the inhibitory action of [D-Met2,Pro5] enkephalinamide. Naloxone (1.5 mumol/kg i.m.) reversed or prevented the inhibitory action of the opioid peptide; naloxone on its own did not influence responses due to 0.3-30 Hz stimulation. [D-Met2,Pro5] enkephalinamide (0.15 mumol/kg i.m.) did not influence basal blood flux in the skin, mean arterial blood pressure, respiratory minute volume or respiratory frequency. It was concluded that stimulation of opioid receptors by [D-Met2,Pro5] enkephalinamide is likely to inhibit stimulation-evoked vasodilatation by reducing the release of vasoactive substances from capsaicin-sensitive afferent neurons, an effect that does not depend on functional integrity of sympathetic nerves. Endogenous opioids probably do not modulate the capsaicin-sensitive vasodilatation.


Immunocytochemical evidence of hypothalamic regulation of adenohypophyseal VIP in the male rat.

In order to check whether hypothalamic stimulatory or inhibitory factors exert any kind of modulation on the morphology of VIP-immunoreactive cells in the rat hypophysis, the transport of these towards the hypophyseal portal system was blocked by intraventricular administration of colchicine in adult male rats, thereafter performing a morphometric study after characterizing the VIP-immunoreactive adenohypophyseal cells by immunocytochemical techniques. Colchicine administration led to a significant increase (p < 0.01) in the number of reactive cells observed. These cells were characterized by a larger cellular area (p < 0.01), owing to increases in nuclear area (p < 0.05) and cytoplasmic area (p < 0.05). Their morphology became more regular, with a predominance of polygonal and oval cells. The results suggest that the VIP-reactive cells of the rat hypophysis are subject to a hypothalamic inhibitory influence and their activity increasing when the hypothalamic effect is interrupted by intraventricular administration of colchicine.


Possible role of cholecystokinin-A receptors in regulation of thyrotropin (TSH) secretion in male rats.

We studied the importance of cholecystokinin (CCK) system in the regulation of thyrotropin (TSH) and prolactin (PRL) secretion in male rats. To this end, we tested the effects of both unselective CCK agonists CCK-8 and caerulein, and CCK-B selective agonists CCK-4 and pentagastrin as well as the selective CCK antagonists (devazepide and L-365,260) at wide dose-ranges on the cold-stimulated and TRH-induced TSH and PRL secretion. Caerulein, given s.c. 15 min before sacrifice, decreased TSH levels at 5 micrograms/kg. In time course-studies, the maximum inhibition was seen at 15 min but the effect lasted at least 30, but less than 60 min. Also CCK-8 decreased TSH levels at the doses of 20 and 50 micrograms/kg at 15 min. Devazepide and L-365,260 did not affect TSH or PRL levels at any dose. The effect of caerulein (5 micrograms/kg) was antagonized by devazepide, a CCK-A antagonist, at 100 micrograms/kg, but not by a CCK-B antagonist L-365,260 tested at a wide dose range. PRL levels were not affected by any treatment. Caerulein (5 micrograms/kg), given at the same time as TRH (500 ng/kg), inhibited the TRH-induced TSH levels at 15 min, but not at 30 or 60 min. CCK-8 (50 micrograms/kg), CCK-4 (100 micrograms/kg) and pentagastrin (500 micrograms/kg) did not affect the TRH-induced TSH secretion. The results probably indicate that CCK-A receptor stimulation inhibits TSH secretion at the level of the anterior pituitary gland. PRL levels in male rats are not affected by CCK system.


Use of polymerase chain reaction nad denaturing gradient gel electrophoresis to identify polymorphisms in three exons of dopamine D2 receptor gene in schizophrenic and delusional patients.

The dopamine D2 receptor gene is a candidate gene for schizophrenia. We screened three exons of this gene for mutations in a large sample of schizophrenics, delusional patients and healthy controls. No structural changes were found, thus suggesting that psychopathology is not related to DNA alterations in the DRD2 gene.


Effect of endothelin on somatosensory evoked potentials in rats.

The effects of endothelin 1 (ET-1; 300 pmol/rat intracarotid) on somatosensory evoked potential were investigated in rats. ET-1 led to an amplitude reduction, peak latency prolongations and waveform disturbances. There was a large interindividual variability. The late cortical components were more affected than the earlier potentials at a thalamic or cortical level. ET-1-induced SEP changes developed quickly after the drug injection and persisted for at least 30 min. It is assumed that the observed effects probably reflect the occurrence of a progressively developing ischemia subsequent to ET-1 administration. Moreover, the pattern of ET-1-induced changes suggests a greater sensitivity of the synaptic transmission to the ischemic influence than the axonal conduction.


Effect of imipramine treatment on heart rate variability measures.

Recently, heart rate (HR) variability has received considerable attention, and a decreased HR variability has been linked to a significant risk of cardiovascular illness. We have previously reported such a decreased variability in panic disorder patients. In this study, we report on HR variability in 12 depressed and 6 panic disorder patients at baseline and 1 and 3 weeks of treatment with imipramine as measured by the standard deviation, mean consecutive difference and the standard deviation of the mean consecutive difference of the R-R intervals in supine, supine deep breathing and standing postures. In all subjects, imipramine (mean dose: 70 mg/day) produced a significant decrease in heart rate variability at week 3 as measured by the above variables. This decrease in HR variability during imipramine treatment is probably due to its anticholinergic effects.


Vascular dementia in the Lundby study. 1. A prospective, epidemiological study of incidence and risk from 1957 to 1972.

In this study, a total population, the 1957 Lundby cohort, was investigated with regard to the incidence of vascular dementia over a 15-year period, and to provide a succeeding study with basic data concerning the background factors for vascular dementia. The 1957 cohort comprises 2,612 persons who were registered in the geographically delimited Lundby area on July 1, 1957. The lifetime risk of developing vascular dementia was found to be 34.5% in men and 19.4% in women when all degrees of impairment were taken into account, the preponderance for the male sex being very obvious.


A multicenter double-blind study of three different doses of the new cAMP-phosphodiesterase inhibitor rolipram in patients with major depressive disorder.

A multicenter randomized 4-week interindividual double-blind study was carried out in 58 hospitalized patients with major depressive disorder (DSM III 296.23, 296.22, 296.33, 296.32, 296.53 and 296.52) to test the dose-effect relationship of three different doses of the new cAMP-phosphodiesterase inhibitor rolipram: 3 x 0.25 mg, 3 x 0.50 mg and 3 x 1.00 mg rolipram/day. With respect to the desired effect, the 3 x 0.50 mg dosage stood out from the others in almost all relevant parameters. With respect to the response rate, the efficacy of the 3 x 0.25 mg dosage was about the same as that reported in the literature for placebo. The inferior performance of the 3 x 1.00 mg dosage compared to the 3 x 0.50 mg dosage might indicate a reverse U-shaped dose-effect relationship. There was good tolerance to all three dosages. There were no findings that might cast doubt on the safety of the dosages tested.


Therapeutic efficacy of pyritinol in patients with senile dementia of the Alzheimer type (SDAT) and multi-infarct dementia (MID).

This trial was performed to investigate the efficacy of pyritinol in the treatment of senile dementia. Initially, a total of 183 inpatients were screened for eligibility. Of 164 patients who met the inclusion criteria, 156 completed the trial. Allocation of the patients to the Senile Dementia of the Alzheimer Type group or the Multi-Infarct Dementia group was based on the Hachinski Ischemic Score, computed tomography scans and electroencephalographic (EEG) findings. In a 12-week double-blind treatment phase either 200 mg pyritinol dihydrochloride-monohydrate or placebo was given 3 times daily. Confirmatory statistics included item 2 of the Clinical Global Impression, the total score of the Short Cognitive Performance Test (Syndrom Kurz Test) and the factor 'cognitive disturbances' of the Sandoz Clinical Assessment Geriatric scale. In addition, data on tolerance, of EEG brain mapping and of a responder analysis were evaluated based on descriptive statistics. The therapeutic efficacy of pyritinol was clearly demonstrated by confirmatory analysis as the drug was statistically significantly superior to placebo in all 3 target variables. The clinical relevance of the outcome was underlined by the analysis of the descriptive variables and by the convergence found at the different observation levels. The EEG mapping demonstrated significant differences between placebo and pyritinol, with the latter decreasing slow and increasing fast alpha and beta activity, which reflects improvement of vigilance. Based on the results of this trial, it can be accepted that the therapeutic effect of pyritinol is superior to placebo in patients with mild to moderate dementia of both degenerative and vascular etiology.


Pharmacologic properties of the internal clock underlying time perception in humans.

Performance on temporal discrimination of time intervals in the range of milliseconds is interpreted by the assumption of an internal clock; the higher the clock rate the better the temporal resolution of the internal clock will be, which is equivalent to more accuracy in timing of brief intervals. Although there is some evidence from animal and human studies suggesting that the clock rate depends on the effective level of brain dopamine (DA), the findings are not conclusive. Therefore, an alternative interpretation of the pharmacologic properties of the internal clock has been introduced. According to this interpretation, the internal timing mechanism can be seen as a biological rhythm that is susceptible to chronomutagenic agents, i.e., pharmacologic compounds that are able to produce an alteration in the period of a biological rhythm. To elucidate the pharmacologic properties of the internal timing mechanism, in a double-blind study either 1750 mg of the DA antagonist alpha-methyl-p-tyrosine (AMPT), 0.65 g/kg ethanol which possesses chronomutagenic effects, or placebo were applied to 80 male subjects. As measures of performance, difference threshold estimates in relation to a 50- and a 1,000-ms standard interval and respective response latencies were computed. Furthermore, urinary levels of DA, DOPAC, and HVA were quantified by HPLC analysis. Although AMPT treatment resulted in a pronounced reduction of more than 50% for DA, DOPAC, and HVA, temporal discrimination was not affected. On the other hand, ethanol induced a significant impairment in performance on temporal discrimination in the range of milliseconds as compared to placebo. Neither temporal discrimination in the range of seconds nor response latencies were affected by the drugs applied in this experiment. Our findings suggest that the internal timing mechanism underlying temporal discrimination of intervals in the range of milliseconds is independent of the effective level of brain DA. More likely, pharmacologically induced changes in clock rate appear to depend on the chronomutagenic effects of the drug applied. Furthermore, the absence of ethanol-induced changes in performance on temporal discrimination of longer intervals in the range of seconds supports the assumption of two distinct timing mechanisms underlying temporal discrimination in the millisecond and second range.


Nerve stump effects in muscle are independent of synaptic connections and are temporally correlated with nerve degeneration phenomena.

Close or distant denervation of the rat soleus muscle indicated that (1) longer soleus nerve stumps delay the onset of axon terminal degeneration and of muscle membrane changes (spike resistance to TTX) by strictly comparable times, and (2) the stump-induced delay of the muscle effect is independent of synaptic connections, because it is also obtained (RMP fall and TTX-resistance development) when sectioning a foreign nerve previously transplanted on the soleus surface but not making synaptic contacts. Both lines of evidence are consistent with the interpretation that, as far as the extrajunctional membrane properties are concerned, the effect of the length of the nerve stump on muscle is mediated by nerve terminal breakdown.


Antidepressants inhibit spontaneous oscillations of intracellular Ca2+ concentration in rat cortical cultured neurons.

In rat cortical cultured neurons, spontaneous oscillations in the intracellular Ca2+ concentration ([Ca2+]i) were observed by direct [Ca2+]i measurements using the fluorescent indicator fura-2. These [Ca2+]i responses were eliminated by the removal of extracellular Ca2-, L-type Ca2+ channel blockers or a glutamate receptor antagonist. Three antidepressants (amitriptyline, imipramine and mianserin) suppressed the [Ca2+]i oscillations in the range of 1-50 microM. In addition, amitriptyline inhibited high K(+)-and glutamate-induced [Ca2+]i increases with IC50 values of 19 and 27 microM, respectively. Imipramine and mianserin also inhibited the high K(+)-induced [Ca2+]i increases with IC50 values of 45 and 24 microM, respectively. These results suggest that blocking actions by the antidepressants on voltage-dependent Ca2+ influx and glutamate receptor-mediated Ca2+ influx may be involved in the suppression of the [Ca2+]i oscillations.


Reliability of quantal parameter estimates and their changes during long-term potentiation in guinea pig hippocampal slices.

Previously we found increases in quantal content (m) and smaller increases in quantal size (v) during long-term potentiation (LTP) in CA1 of hippocampal slices. However, the validity of the deconvolution technique was questioned recently because v estimates correlated with the noise standard deviation (Sn). In computer simulations we show a double-step dependence of v on Sn/v: correct v estimates (within +/- 20%) for Sn/v < or = 0.5 and overestimates (correlated with Sn) for Sn/v > 0.5. A novel 'noise addition' procedure is proposed for accepting reliable solutions on the basis of the double-step relationship between v and Sn. Quantal analysis of LTP for more reliable solutions confirmed previous conclusions.


The effect of peripheral loading with kynurenine and probenecid on extracellular striatal kynurenic acid concentrations.

Kynurenic acid (KYA) is the only known endogenous excitatory amino acid antagonist in mammalian brain. In the present study we examined the effects of precursor loading with kynurenine (KYN) and blockade of organic acid transport with probenecid, either alone or in combination, on extracellular striatal KYA concentrations in unanesthetized rats. Baseline KYA concentrations were 1.61 +/- 0.29 pmol/ml. Following administration of KYN 150 mg/kg with increasing doses of probenecid a maximal increase in KYA to 946 +/- 210 pmol/ml was seen with probenecid 200 mg/kg. Probenecid 200 mg/kg alone increased KYA levels to 16.0 +/- 5.2 pmol/ml. The combination of probenecid 200 mg/kg with KYN 450 mg/kg produced a maximal increase of KYA to 2085 +/- 391 pmol/ml, a 1300-fold increase indicating marked potentiation. These results show that pharmacologic manipulation can markedly increase extracellular fluid concentrations of KYA into a range which may be useful in attempts to block NMDA receptor-mediated neurotoxicity.


In situ DNA-protein binding: a novel method for detecting DNA-binding activity of transcription factor in brain.

A novel method, in situ DNA-protein binding (in situ DPB), was developed to detect the distribution and DNA-binding activity of AP-1 and Sp1 binding proteins in situ. The regional distribution of AP-1 binding protein in mouse brain was different from that of Sp1. Antibody against the DNA-binding domain of Jun protein markedly reduced the AP-1 but not the Sp1 binding activity. The binding activity of AP-1 probe increased markedly in the brain after administration of methamphetamine. These results suggest that the in situ DPB is convenient and sensitive for detecting the distribution and the DNA-binding activity of transcription factors in situ.


Intact conduction of fastest corticospinal efferents is not sufficient for normal voluntary muscle strength: transcranial motor cortex stimulation in patients with tetraplegia.

In six patients with chronic severe tetraparesis, caused by closed head injury (3 cases), basilar thrombosis (2 cases) or global hypoxia (1 case), responses of suprathreshold transcranial magnetic stimulation of motor cortex to thenar and abductor hallucis muscles on both sides were studied. Results showed in most patients normal thresholds and latencies (17 out of 24 latencies within normal +/- 2 S.D., 20 thresholds within normal +/- 1 S.D.) and amplitudes of even higher than normal values. Latencies or thresholds did not correlate with severity of pareses and were in marked contrast to the severe pareses of the muscles under investigation. Despite different etiology CT-scans showed diffuse atrophy of cerebral white matter as a common finding. It is concluded that intact descending corticospinal motor pathways are a necessary but not a sufficient condition for voluntary motor function.


Spatio-temporal pattern of frequency representation in the auditory cortex of guinea pigs.

The spatio-temporal pattern of sound-evoked neural activity in the guinea pig auditory cortex was studied by optical recording with the aid of voltage-sensitive dye. Changes in light intensity induced by sounds at various frequencies and pressure levels were recorded with a 12 x 12 array of photodiodes. The amplitudes of the responses were displayed as sequential two-dimensional images. Tonotopical organization was found in two subdivisions of the auditory cortex, the anterior field (field A) and the dorsocaudal field (field DC). The frequency gradients in fields A and DC had a mirror-image relationship. This agrees with results obtained by the microelectrode technique. However, the tonotopic response observed in our study was transient. The focal activity that began in field A propagated in two directions; dorsally along the iso-frequency bands in field A, and caudally toward field DC. This suggests that the sound information processing initiates at field A, and its outputs are transferred to field DC, which is probably a hierarchically higher center.


Neurotoxic damage evokes regenerative responses from adult rat sensory neurones.

When adult rats were pre-treated systemically with the excitotoxin, capsaicin, a subset of their dorsal root ganglion (DRG) sensory neurones responded as if they had been axotomised. Firstly, an increased proportion of capsaicin-sensitive DRG neurones (identified by using a cobalt stain) vigorously extended processes in vitro. Additionally, a subset of small dorsal root ganglion neurones expressed elevated levels of the growth-associated protein-43 (GAP-43) in situ. Both vigorous neuritogenesis and elevated GAP-43 levels are characteristics of neurones that are actively regenerating following mechanical damage. Although capsaicin-treated adult DRG neurones show these regenerative responses, their C-fibers fail to regenerate in vivo.


Mutual excitation among dorsal root ganglion neurons in the rat.

Intracellular recordings were obtained from primary sensory neurons in excised dorsal root ganglia (DRGs). Most (90%) neurons sampled became depolarized during periods of repetitive stimulation of a branch of the dorsal root (DR) which contained only axons of neighboring neurons. DR stimulation also evoked a transient rise in extracellular K+ concentration ([K+]o), following similar kinetics. Thus, the mutual excitation among DRG neurons may be mediated by [K+]o. Activity-dependent cross-excitation in DRGs could contribute to neuropathic sensory abnormalities often triggered by nerve injury or disease.


Evidence that neuropeptide Y secretion in the median eminence increases prior to the luteinizing hormone surge in ovariectomized steroid-primed rats: estimation by push-pull perfusion.

Utilizing the push-pull perfusion technique, we examined the secretory profiles of neuropeptide Y (NPY) and luteinizing hormone (LH)-releasing hormone (LHRH) in the median eminence (ME) of ovariectomized adult rats which were primed with estrogen and progesterone to provoke LH and prolactin (PRL) surges. The ME was perfused with artificial cerebrospinal fluid between 13.00 and 18.00 h, and perfusates and blood samples were collected every 20 min. NPY and LHRH in the ME started to significantly increase 40 min earlier than the initial significant rise in the plasma LH, and the highest ME levels of the neuropeptides clearly preceded the occurrence of the LH surge. Regarding the PRL surge, however, such temporal relationship was not apparent. These in vivo data appear to support the putative facilitatory role of NPY in the generation of the steroid-induced LH surge. This is the first study to characterize the temporal profile of in vivo release of NPY in rat ME in terms of its relationship to LH and PRL surges.


Alterations in medial perforant path and mossy fiber induced field potentials in amygdala and beta-carboline (FG 7142) kindled rats.

We tested in rat hippocampal slices whether kindling causes sprouting of mossy fibers thereby augmenting excitatory coupling and epileptogenicity. Field potentials (fp's) evoked by orthodromic stimulation of the medial perforant path (MPP) and antidromic stimulation of mossy fibers in slices from control, amygdala kindled (AK) and beta-carboline (FG 7142) kindled rats were recorded in the dentate gyrus granule cell layer. Orthodromic paired pulse inhibition was increased in both groups of kindled animals. In contrast, neither in normal medium nor under additional application of the GABAA receptor antagonist bicuculline nor in Mg(2+)-free artificial cerebrospinal fluid (ACSF) there was evidence for an excitatory field EPSP component upon stimulation of mossy fibers in any of the investigated groups. The results indicate that functional mossy fiber sprouting does not occur as an obligatory step in the induction of kindling epilepsy.


Hypothermia protects astrocytes during ischemia in cell culture.

A mild decrease in temperature (2-3 degrees) can result in marked attenuation of ischemic neuronal damage in living animals. We now report the protective effects of hypothermia in an astrocyte with simulated ischemia in cell culture system. Hypothermia when used during ischemia showed significant reduction of damage. Brief episodes of post-ischemic hypothermia were not protective whereas more prolonged post-ischemic hypothermia showed moderate protection. Cell culture systems may prove to be useful tools to study the mechanisms of hypothermic protection during ischemia.


Barbiturate promotes post-ischemic reaggregation of polyribosomes in gerbil hippocampus.

A brief period of cerebral ischemia is followed by severe inhibition of protein synthesis which is slowly reversed in the resistant but not in the selectively vulnerable regions of the brain. Inhibition occurs at the translational level, as evidenced by the disaggregation of ribosomes into monosomes. In order to evaluate the importance of this disturbance for the evolution of ischemic injury, the effect of the neuroprotective drug, pentobarbital, on ribosomal aggregation was studied in gerbils subjected to 5 min bilateral carotid artery occlusion. Pentobarbital (50 mg/kg, i.p.) was applied shortly after the ischemia, and the aggregational state of ribosomes was investigated by electron microscopy after recirculation times ranging from 15 min to 1 day. Pentobarbital treatment did not prevent the initial post-ischemic disaggregation but promoted the subsequent reaggregation in the selectively vulnerable neurons. This suggests that post-ischemic application of barbiturates exerts its beneficial effect by reversing the post-ischemic block of ribosomal reaggregation in vulnerable regions.


Pharmacological properties of the homomeric alpha 7 receptor.

The pharmacological properties of the alpha-bungarotoxin sensitive alpha 7 neuronal nicotinic acetylcholine receptor (nAChR) were studied upon reconstitution in Xenopus oocytes. Channels formed by alpha 7 are about 10-fold more sensitive to nicotine and cytisine than to ACh but are little, if at all, activated by the ganglionic agonist 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). Tubocurarine (TC) was found to act as a non-competitive inhibitor, whereas dihydro-beta-erythroidine (DH beta E) behaves as a pure competitive inhibitor whose blockade is fast and fully reversible. In addition, the alpha 7 receptor displays a poor sensitivity to methonium salts. The pharmacological properties of the alpha 7 channels are readily distinguishable from those of other identified neuronal nicotinic receptors.


The primary auditory cortex in cetacean and human brain: a comparative analysis of neurofilament protein-containing pyramidal neurons.

To extend our investigation of the anatomy of sensory systems in highly adapted aquatic and terrestrial mammals, we have analyzed the distribution of a particular population of efferent neurons in the cetacean and human primary auditory cortex using an antibody to non-phosphorylated neurofilament protein (SMI32). The neurofilament protein triplet is differentially distributed within neuronal subpopulations in the primate and cetacean neocortex. In primates, it appears that the somatodendritic domain of a subset of pyramidal neurons furnishing specific corticocortical connections contains high concentrations of neurofilament protein. In the human primary auditory cortex these neurons are located in layers III, V and VI, whereas in cetaceans they are concentrated almost exclusively in the cortical efferent layer IIIc/V. Previous analyses have shown that SMI32 immunoreactivity in the cetacean neocortex is uniformly distributed among functionally different areas, while in human neocortex, the distribution of SMI32-positive neurons exhibit a high degree of regional and laminar specialization that is correlated with the functional and anatomical diversity of the cortical areas. In addition, the overall distribution of SMI32-immunoreactive neurons in the cetacean neocortex is comparable to that observed in paralimbic areas of the human, suggesting that the cetacean neocortex has retained many features of phylogenetically older cortical regions.


Immunocytochemical and in situ hybridization detection of hypothalamic neuropeptides from postmortem unfixed rat brains.

The effects of postmortem delay on neuropeptide-containing perikarya was studied in the paraventricular nucleus (PVN) of the rat hypothalamus. Serial sections from brains kept in the skull after death for 6 h and immunocytochemically processed for oxytocin (OT), vasopressin (AVP) and corticotropin releasing factor (CRF) or hybridized in situ for CRF resulted in the well preserved phenotypic expression and stability of mRNA of the aforementioned neuropeptides. Furthermore in most cases, AVP and CRF expression was discernibly enhanced relative to prefixed immunopositive tissue. Results of this study suggest that postmortem variables do not significantly alter the neurochemical coding of magnocellular or parvocellular neurosecretory systems, and support the view that rat and human brain topography can be investigated from tissue left in situ after death for a relatively long period of time.


Ectopic impulse generation in dorsal root ganglion neurons during methylmercury intoxication: an electrophysiological and morphological study.

Electrophysiological function and morphology of dorsal root ganglion (DRG) neurons were investigated in female Wistar rats following administration of methylmercury (5 mg/kg/day for 10 days). Neurons were classified according to the conduction velocities of their peripheral axons and perikaryal action potential characteristics as types A alpha, A beta A delta and C. In methylmercury-treated rats, the majority of DRG neuron action potential characteristics were not significantly altered. However, axonal conduction velocities were slowed in all type A ganglion cells, leading to significant delays in action potential onset in types A beta and A delta neurons. An initial complex-soma inflection was observed on the rising phase of the action potential of some cells. These inflection potentials had longer conduction times and lower amplitudes in treated animals. Repetitive discharge, characterized by 3-5 action potentials upon single peripheral nerve stimulation, was observed in 8 of 38 cells recorded in treated animals, predominantly in type A beta (4/8) and A beta (3/12) neurons; direct current injection into repetitively discharging cells via the recording electrode elicited only single action potentials. Extracellular recordings from dorsal root filaments confirmed that the repetitive action potentials arising in the DRG were conducted to the spinal cord. Morphological examination of DRG revealed damage in up to 10% of neurons, consisting of loss of Nissl staining, cytoplasmic vacuolization, and proliferation of satellite cells. Large, pale neurons appeared preferentially involved. Rarely, neuronophagia was observed. Further microscopic examination of proximal and distal sections of sciatic and tibial nerves revealed only occasional degeneration of myelinated axons. While morphological alterations did not appear to offer a structural basis for the multiple firing, it is speculated that repetitive action potential discharge may contribute to the paresthesias associated with MeHg intoxication.


The acute retinal histopathology of MPTP.

The effects of MPTP on the retina have been examined with emphasis on the effects that are apparent within a few hours of administration. Histopathologic changes were found within one day after MPTP administration. These changes were most prominent in the Muller cells, which demonstrated edematous changes in the cellular processes and occasionally pyknotic nuclei in the inner nuclear layer. Capillary endothelial cells also were damaged by MPTP administration as evidenced by disruption of the cellular cytoplasms. This damage may have caused pooling of blood in the blood vessels of the retina. Finally, mitochondria in some retinal layers may have been altered by MPTP administration with swelling and possible rupture seen in some cells. These acute effects of MPTP may be involved in the formation of lesions to dopaminergic amacrine cells found in the retina following MPTP exposure.


Effects of low level styrene exposure on psychological performance in FRP boat laminating workers.

To evaluate the effects of low level styrene exposure on psychological performance, picture completion and digit symbol tests (subtests of the Wechsler Adult Intelligence Scale) and the Maudsley Personality Inventory were administered to 12 male laminating workers in a factory producing reinforced fiberglass boats. Airborne styrene concentrations at the workplace were 26 +/- 24 (mean +/- SD) ppm (range 1-77) 3 mon before testing, and 14 +/- 1 ppm (6-46) 2 mon after testing; on the day of testing, the exposure levels, as estimated from levels of styrene metabolites in end-of-shift urine samples, were 22 +/- 17 (mean +/- SD) ppm (range 0-61). Scores on the picture completion test were significantly decreased in these workers, suggesting that psychological performance is adversely affected by occupational styrene exposures at levels of 77 ppm or below.


Extracellular acetylcholine changes in rat limbic structures during soman-induced seizures.

Extracellular acetylcholine (ACh) levels were determined, by intracranial microdialysis, in medial septum, amygdala and hippocampus (CA1, CA3, dentate gyrus) of rats during seizures induced by systemic administration of soman (pinacolyl methylphosphonofluoridate), a potent inhibitor of acetylcholinesterase (AChE). In all septo-hippocampal areas a two phase variation was observed: a primary increase in ACh during the pre-seizures period, followed by a decline after 10 to 20 min of seizures and then a second release at 50 min of seizures. In amygdala a progressive increase of the ACh level reached a maximal value at 50 min. ACh levels than returned to basal values in all areas. Hippocampal AChE activity remained totally inhibited throughout the experiment. Possible dynamic phenomena underlying these variations (blood-brain barrier opening, autoregulation of release) are suggested. The present results are compared to previous reports about glutamate changes in the same areas during soman seizures. This comparison gives evidence that in septo-hippocampal areas the glutamatergic system is recruited after an early accumulation of extracellular ACh. The respective roles of ACh and glutamate in triggering and maintenance of soman seizures activity are discussed.


Trimethyltin alters membrane properties of CA1 hippocampal neurons.

Trimethyltin produces pathological changes in the hippocampus, but the physiological mechanisms underlying its toxicity remain unclear. Intracellular recordings of CA1 neurons in rat hippocampal slices were conducted during bath application of 50 and 100 microM trimethyltin and 50 and 200 microM dimethyltin. Trimethyltin slowly depolarized the membrane potential without spontaneous spiking, and decreased input resistance and time constant. Trimethyltin decreased, in a dose-dependent manner, both the elicited action potential and the orthodromically-stimulated action potential amplitudes; increased the threshold current for both elicited and orthodromically-stimulated action potentials; and prolonged the duration of the orthodromic excitatory post-synaptic potential. These trimethyltin-induced effects were not readily reversed. On the other hand, dimethyltin at high concentrations only reduced the amplitude of the orthodromic action potential. Slice viability was compromised following exposure to trimethyltin, but not following dimethyltin. These data demonstrate that decreased membrane time constant and input resistance is an early and reliable indicator of the onset of trimethyltin-induced changes. The effects do not resemble those produced by excitotoxins, but rather share similarities with responses observed during slice hypoxia.


Effect of lead during different developmental periods in the monkey on concurrent discrimination performance.

A total of 52 monkeys (Macaca fascicularis) were dosed orally with vehicle or 1.5 mg/kg/day of lead according to one of four dosing regimens (13 monkeys/group): Group 1, vehicle only; Group 2, dosed with lead continuously from birth; Group 3, dosed with lead from birth to 400 days of age and vehicle thereafter; Group 4, dosed with vehicle from birth to 300 days of age and lead thereafter. Blood lead concentrations averaged 3-6 micrograms/dl when monkeys were not dosed with lead, 32-36 micrograms/dl when being dosed with lead and having access to infant formula, and 19-26 micrograms/dl when being dosed with lead after weaning from infant formula. When monkeys were 8-9 years old, they were tested on two sets of concurrent discrimination tasks, each consisting of 6 stimulus pairs. Group 2 required more sessions on Task 1 for 5 of the 6 pairs to reach a criterion of 90% correct, while Groups 3 and 4 required more or marginally more sessions on 4 of the 6 pairs. On Task 2, Group 2 required more sessions to reach criterion for most pairs, Group 4 was marginally impaired, and Group 3 was unimpaired. All three treated groups made more perseverative errors than controls on Task 1, but not on Task 2. There were no differences between groups for response latency or position bias. This extends previous research with these monkeys, in which impairment was observed on spatial and nonspatial discrimination reversal, and spatial delayed alternation.


Calcium, magnesium and aluminum concentrations in Parkinson's disease.

Concentrations of calcium (Ca) and aluminum (Al) were measured by neutron activation analysis and that of magnesium (Mg) by inductively coupled plasma emission spectrometry in 26 regions of Parkinson's disease (PD) and control brains. Ca concentration was unchanged in all anatomic subregions of PD brains compared with control brains. Mg concentration was lower in cortex, white matter, basal ganglia and brain stem of PD brains compared to control brains (p < 0.01). Al concentration in the substantia nigra, caudate nucleus and globus pallidus was higher in PD brains compared to controls (p < 0.05) and significantly higher in gray matter and the basal ganglia (p < 0.01). These studies are consistent with other observations linking high concentrations of Al and low levels of Mg in the pathogenesis of CNS degeneration and PD.


Concurrent changes in regional cholinergic parameters and nest odor preference in the early postnatal rat after lead exposure.

The effect of pre- and postnatal lead ingestion on choline acetyltransferase (ChAT) activity, muscarinic cholinergic receptors (mACHR) and on nest odor preference, was investigated in the early postnatal male rat. Long Evans dams were given either 0.15% [LL = low lead] or 0.25% [ML = moderate lead] lead acetate (controls, 0.125% or 0.075% sodium acetate) in their drinking solution from the first day of pregnancy and during lactation. Mean blood lead levels were 55 micrograms/100ml at postnatal day [PN] 6 in ML-treated offspring and 35 micrograms/100ml at PN 9 in LL-treated pups. General health of pups and dams was not affected. Lead-treated offspring showed a reduced preference for or ability to identify the smell of home bedding, when tested at PN 9. A decrease in binding (Bmax) of [3H]N-methyl- scopolamine (NMS) was detected in olfactory bulb and in visual cortex of LL-treated rats at PN 9; the affinity (KD) was unchanged. On the other hand, ChAT-activity of ML-treated offspring was significantly increased in olfactory bulb at PN 6. These results suggest that stage-specific behaviors depending on sensory functions and cholinergic projection systems in related brain areas are sensitive to pre- and postnatal lead exposure.


Reactive oxygen species formation as a biomarker of methylmercury and trimethyltin neurotoxicity.

Reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, and hydroxyl radicals are believed to be initiators of peroxidative cell damage. This paper focused on the use of 2',7'-dichlorofluorescein-diacetate (DCFH-DA) to quantitate cerebral ROS as an index for neurotoxicity. This technique employs an assay of dichlorofluorescein (DCF), the fluorescent product of dichlorofluorescein (DCFH). Data from studies using various free radical generating systems, several iron chelators and hydroxyl radical scavengers suggest that DCFH oxidation may result in several reactive intermediates. In a biological system (synaptosomes isolated from untreated rats) DCF fluorescence was stimulated by ascorbate or FeSO4, while deferoxamine inhibited the ascorbate/FeSO4-induced stimulation of DCF formation. Two organometals, methylmercury (MeHg) and trimethyltin (TMT), known to produce neurotoxicity were tested. In vitro exposure to MeHg (10-20 microM) increased the rate of formation of ROS while TMT (5-40 microM) had no effect. In vivo, 48 hr and 1 week after a single injection of MeHg (1 mg/kg, i.p.) in mice and 1 week after a single injection of MeHg (5 mg/kg, i.p.) in rats, the rate of formation of ROS in both rat and mouse cerebellum was significantly increased. Pretreatment with deferoxamine, a potent iron-chelator, prevented MeHg-induced increase of ROS. In hippocampus and frontal cortex, ROS formation rates were also elevated 48 hr after TMT injection (3 mg/kg, i.p.) in mice. These results demonstrate that DCF fluorescence provides a good measure of overall ROS formation in synaptosomes of both in vitro as well as in vivo systems. Since ROS formation was selectively increased in areas known to be specifically vulnerable to organometals (cerebellum in the case of MeHg and hippocampus in the case of TMT), these studies further support that oxidative damage may be the primary mechanism underlying the neurotoxicity induced by these organometals.


Potential of memantine, D-tubocurarine, and atropine in preventing acute toxic myopathy induced by organophosphate nerve agents: soman, sarin, tabun and VX.

Male Sprague-Dawley rats when administered sc a sublethal dose of organophosphorus cholinesterase inhibitors such as the nerve agents, soman (100 micrograms/kg, sc), sarin (110 micrograms/kg, sc), tabun (200 micrograms/kg, sc), or VX (12 micrograms/kg, sc), developed seizures and severe muscle fasciculations within 15-20 min, lasting for 4-6 hr. Marked inhibition of acetylcholinesterase (AChE) and necrotic lesions in skeletal muscles such as soleus, extensor digitorum longus, and diaphragm were evident between 1-24 hr following injection. Pretreatment with memantine HCl (MEM, 18 mg/kg, sc) together with atropine sulfate (ATS, 16 mg/kg, sc), 60 min and 15 min, respectively, prior to nerve agents attenuated AChE inhibition, prevented myonecrosis, and muscle fasciculations as well as other signs of cholinergic toxicity. Pretreatment combining d-tubocurarine (d-TC, 0.075 mg/kg, sc) and ATS (16 mg/kg, sc) prevented the myonecrosis and fasciculation without protecting AChE against inhibition by these nerve agents. Neither MEM, d-TC, nor ATS in the concentration given interfered with the normal behavior of the rats. The role of d-TC and ATS interaction with presynaptic receptors regulating ACh release and MEM's role in modulating neural hyperactivity as protective mechanisms are discussed.


Ganglioside treatment partially counteracts neurotoxic effects of trimethyltin but may itself cause neurotoxicity in rats: experimental results and a critical review.

We have demonstrated a deficit in working memory and/or consolidation of information in working memory into reference memory by a single oral dose of the neurotoxin trimethyltin(TMT). Moreover, TMT causes loss of hippocampal corticosterone receptors and increases brain glial fibrillary acidic protein(GFAP), an index of the astrocytic reaction to diverse types of CNS lesions. We tried to block the TMT-induced cognitive deficit and these biochemical markers by treating rats with purified mixed gangliosides (GS) for 21 days, starting 2 days before the TMT treatment. As expected, TMT decreased the number of corticosterone receptors in hippocampi and increased the GFAP concentration in hippocampi and to a lesser extent, in frontal cortices, measured more than 8 mon after treatment. The small increase in GFAP in frontal cortices was attenuated by GS but not in hippocampi. The pronounced learning deficits caused by TMT were attenuated to a small extent by GS in the TMT-GS group, when a learning criterion was used for the last session's performance of acquired lever-directed behavior. GS also delayed the appearance of significant performance differences between Controls and TMT-treated rats, when probed with a progressive fixed ratio schedule of reinforcement. However, most measures of learning and performance indicated that GS did not block the dysfunctional consequences of TMT treatment but instead caused similar functional decrements in rats treated with water instead of TMT. Corticosterone receptors in hippocampi were reduced to about 65% of Controls in the TMT-Water, TMT-GS, and Water-GS groups. A reduction in corticosterone receptors in hippocampi after TMT treatment probably reflects the loss of one or more cell types (e.g., pyramidal cells), which is supported by the increase in GFAP in this region. However, we did not observe a reciprocal relation between steroid receptors and GFAP after GS alone, indicating that GS did not cause detectable cell loss or cell damage, measured in this manner. Thus, reactive gliosis probably was not a pre-condition for the cognitive dysfunction. The fact that the cognitive deficits are probably related to hippocampal dysfunction supports the notion of a causal relationship between corticosterone receptor reduction and/or their altered function and cognitive impairment of this special type. The possibility that our results demonstrate potential neurobehavioral toxicity of GS is discussed in light of many reports which present data that can be similarly interpreted.


Reproductive hazards in the workplace.

The growing public concern about the presence of toxic substances in the working and living environments has increased the awareness of prospective parents on the potential reproductive damage that may occur as a result of occupational exposure. The obstetrician or gynecologist attempting to counsel a couple about reproductive damage of specific occupational exposure faces a dilemma because of conflicting factors that need to be taken into account. Those factors include lack of a well-defined relationship between exposure at the worksite and reproductive damage, lack of information or conflicting data, economic concerns, and sex discrimination issues. This review describes pathogenic mechanisms of reproductive damage produced by occupational chemical exposure and details common weaknesses and problems in the interpretation and application to clinical practice of the burgeoning literature in the subject. A listing of different chemicals and physical agents suspected of producing reproductive impairment in either membrane of the reproductive dyad is presented. In addition, the legality of the so called "fetal protection policies" is also reviewed. Despite the current scientific uncertainty, knowledgeable health professionals can help parents reach an informed decision about the reproductive risks that they are willing to take when a "zero exposure" environment cannot be guaranteed and allay unfounded fears.


Age-related cataract in the hereditary cataract rat (ICR/1): development and classification.

Lens opacification of the Ihara hereditary cataract rat (ICR/1 rat) was followed up with slit lamp biomicroscopy and photography up to 1 year after birth. The development of lens opacities was first recognized in the anterior superficial cortex of the equatorial region between 30 and 44 days of age. It progressed to maturity around 93-107 days after birth. Cataract development was classified into six stages. The increase of lens weight indicated a continuous lens growth after birth which seemingly even continued after the occurrence of lens opacities. After around 60 days of age, the lens showed a continuous increase of water content, suggesting a participation of increased water content in lens opacification.


Effect of moxisylyte hydrochloride (alpha 1-blocker) on the retinal circulation of patients with diabetes mellitus.

Moxisylyte hydrochloride (alpha 1-blocker) selectively vasodilates cerebral vessels without reducing blood pressure. We investigated the effect of the drug on retinal circulation in 15 patients (17 eyes) with diabetes mellitus, using the video-densitometric image analysis of fluorescein angiography. We compared the build-up time (BT), the time constant of washout rate (TC) and the mean circulation time (MCT) before and after oral therapy with moxisylyte. In 16 eyes, BT was shortened significantly and MCT was only slightly shortened 1 h after oral therapy with moxisylyte. After 2 weeks of daily administration, MCT was shortened and TC of the artery was increased significantly in 6 eyes. Since retinal circulation in patients with diabetes mellitus was improved by moxisylyte, the drug may be useful to treat ocular disorders such as diabetic retinopathy.


Axial length and scleral thickness effect on susceptibility to glaucomatous damage: a theoretical model implementing Laplace's law.

Laplace's law relates the pressure inside a hollow sphere with its radius and the tension in its walls. A theoretical model implementing Laplace's law in the eye globe is presented. The physical model may help to explain certain aspects in glaucomatous disk damage such as higher susceptibility of myopic eyes to glaucomatous damage and a possible explanation for glaucoma nerve head damage in low tension glaucoma.


Changes of urea-soluble and intrinsic membrane proteins in rat lenses during the formation of galactose cataract.

Urea-soluble and intrinsic membrane proteins from normal and galactose cataractous rat lenses were analyzed by SDS-PAGE. During cataract formation, MP22 increased whereas MP26 decreased almost to nil and MP24 emerged. However, the relative amount of MP18 remained essentially unchanged. These results suggested a conversion of MP26 to MP22 during cataract formation. We also observed the changes in the relative abundance of the polypeptides of the urea-soluble fraction with cataractogenesis.


Morphological studies on cataract and small lens formation in neonatal rats treated with monosodium-L-glutamate.

Changes in the transparency and size of lenses in rats were investigated following administration of monosodium-L-glutamate (MSG). MSG (5 mg/g b.w.) was injected subcutaneously on the 9th and 10th day after birth. Ophthalmoscopically, localized opacity was apparent at the posterior pole of the lens corresponding to the attached site of the hyaloid vessels at the 1-month stage. The incidence of cataract increased with age, reaching more than 75% at 4 months. Morgagnian globules were histologically detected in the opacity of the posterior lens cortex. The size and weight of the lens were smaller than those of the control rats. These findings indicate that the administration of MSG could be an etiologic factor in cataract formation in the developing rat.


Direct approach to identification, at the molecular level, of modified proteins in human nuclear cataractous lenses: beta-crystallin is a component of the urea-insoluble protein fraction.

In an effort to elucidate the molecular changes which take place in the human lens with the onset of nuclear cataract, the urea-insoluble protein fraction, solubilized with dithiothreitol, was digested with trypsin. Tryptic peptides separated by HPLC, were examined by both mass spectrometry and Edman degradation. A pentapeptide Gly-Glu-Tyr-Pro-Arg which is contained within the beta-crystallin sequence was isolated. This finding provides direct evidence that beta-crystallin is present in the urea-insoluble protein fraction which is known to be characteristic of human nuclear cataract lenses.


Interphotoreceptor matrix in the colored-light-adapted rat.

The interphotoreceptor matrix (IPM) was examined histochemically using colloidal iron, wheat germ agglutinin and Ricinus communis agglutinin-1 for rats adapted to blue, green or red light before tissue preparation. In blue- and green-light-adapted animals, IPM was intensely stained in the apical zone of photoreceptor outer segments and in the outer and inner segment junction, conforming to the light pattern of IPM distribution in previous studies. In red-light-adapted animals, the IPM was prominent and uniform in the interstitial zone of photoreceptor outer segments, consistent with the dark pattern. The results indicate that rod photoreceptors are predominantly responsible for light-evoked changes in IPM.


[Changes in Contrast Sensitivity after Iodine Treatment in Bad Hall in Patients with Age-Related Maculopathy].

After a cure with iodine in Bad Hall (Upper Austria), patients with age-related maculopathy repeatedly reported improvement in visual power: the picture seen seems to be clearer on the whole or more distinct. These statements were checked in 50 patients with beginning age-related macula degeneration ('dry form') using the 'Vision Contrast test system (VCTS 6500)'. The analysis of the results showed that there is indeed a statistically highly significant improvement in contrast sensitivity after the cure (p < 0.0001). The spontaneous observations of the patients were therefore confirmed by the study.


Neuroepithelial adenocarcinoma of the eye.

A 29-year-old male patient with a microphthalmos on the right side since birth was seen in June 1987 in the University Eye Clinic because of a massive exophthalmus of the former microphthalmic eye. Computer tomography revealed a diffuse, infiltrating tumor of the right orbit. The bulbus was not demarcated, and the whole orbita had to be eviscerated. Histologically, we found a solid, undifferentiated tumor with clear signs of malignancy. It consisted of epithelial cells, partly in nest formation, which were keratin positive and vimentin negative, and of more spindle-shaped formations which were keratin negative and vimentin positive. In some areas, the tumor showed a tubular or an adenoid proliferation. CEA or S-100 could not be demonstrated. The histopathological diagnosis was neuroepithelial adenocarcinoma of the eye. The differential diagnosis and the genesis of the tumor are discussed.


Normal intraocular pressure in man.

Whereas the values of 120/70 mm Hg are universally recognized as being normal for the parameter of systemic blood pressure, the value for 'normal intraocular pressure' remains very vague. Indeed, values between 7 and 21 mm Hg are often considered normal. However, a careful review of the literature and original data reported here suggest that the intraocular pressure in normal subjects, although dynamic, is a more accurate parameter than is generally expected. The normal value during the day in healthy, young adults is about 12 +/- 2 mm Hg, and it increases by 1 mm Hg per decade after 40 years of age.


[Treatment of Ocular Chlamydial Infection: Comparison of Tetracyclines and Norfloxacin].

The unilateral follicular conjunctivitis with corneal marginal infiltrates represents a clinical picture typical for two different types of bacteria: chlamydiae may cause a keratoconjunctivitis always combined with urethritis or colpitis; on the other hand staphylococci may be the reason for the same clinical features, whereas the marginal corneal infiltrates are caused in these cases by immunological reactions to the bacterial toxins. After harvesting material for bacterial investigations or direct immunofluorescence test for the detection of chlamydial antigen, 2-3 days are necessary until the results of the examinations are ready. From January 1991 until the end of 1991 a total of 60 patients with the diagnosis of chlamydial infection underwent ophthalmological investigations at our outpatient clinic. In our study we compared the efficacy and safety of topical tetracyclines and 0.3% norfloxacin solution in the treatment of chlamydial keratoconjunctivitis. Within the bacterial genus, staphylococci (S. aureus, S. epidermidis and S. saprophyticus) were the most frequently isolated organisms (60%). Nearly one third of the staphylococci were resistant to tetracyclines. Therefore there are two indications to postulate norfloxacin as a practicable alternative: at the beginning of therapy until the results of the bacterial investigation are available and in the case of persisting bacterial superinfection.


Fluorescein-angiographic patterns in patients with central serous chorioretinopathy at the initial visit.

We reviewed the clinical records, color photographs and fluorescein angiograms of 106 eyes of 53 patients (44 men and 9 women) with central serous chorioretinopathy who had been followed up for 1 year or more. Their ages ranged from 20 to 59 years. One eye in each patient was involved at the initial visit. According to fluorescein-angiographic findings, the lesions were divided into smokestack pattern (13 eyes), ink blot appearance (33 eyes) and minimally enlarging spot (7 eyes). Most patients complained of central scotoma, and most patients had moderately decreased visual acuities at the initial visit, which improved after recovery. In particular, all 7 eyes with a minimally enlarging spot had a visual acuity of 0.8 or more at the initial visit; of these 6 eyes had 1.0 or more several weeks later. On fluorescein angiography, 49 eyes demonstrated 1 leaking spot and 4 eyes showed 2 spots. Of 57 leaking spots, 10 were observed in the foveola, 31 were noted in the fovea and 16 were found in the para- or perifovea. Of 13 smokestack patterns, 5 were found in the inferonasal area. The ink blot appearance and minimally enlarging spots were frequently found in the superonasal and superotemporal areas.


Exudative retinal detachment subsequent to retinal vein occlusion.

Previous studies have shown the possible development of exudative retinal detachment (ERD) as a complication of retinal vein occlusion (RVO). Considering 473 consecutive cases of RVO, only 3 cases of ERD with peculiar clinical aspects were discovered. In the first case, the ERD followed a branch RVO, but it developed in the opposite quadrant, with a late occurrence of venous retinal collaterals. In the second case, the ERD developed after a central RVO, having a retinoschisis aspect, with the subsequent occurrence of optic disk collateral vessels. In the third case, the ERD was secondary to a hemicentral RVO and involved the entire macular area. The pathogenesis of the ERD subsequent to RVO is still debated. Our experience seems to indicate that the ERD pathogenesis is linked not only to an inability of the draining vascular system, but also to an impairment in the function of the retinal pigment epithelium.


Ischemic optic neuropathy in a female carrier with Fabry's disease.

We report ocular findings of a patient with anterior ischemic optic neuropathy (AION) and cilioretinal artery occlusion in a female carrier of Fabry's disease. Fluorescein angiography revealed delayed filling of the upper and temporal part of peripapillary choroidal vessels and capillaries of the right optic disk and late filling of the cilioretinal artery. CT scanning was performed several times in early stages and demonstrated thickening of the intraorbital optic nerve due to ischemic edema. About 5 months later, the fellow eye showed optic disk edema, an early sign of AION, and was treated by systemic corticosteroid and urokinase whereby AION did not progress.


Effects of topically applied 2% epinephrine and 0.1% dipivalyl epinephrine on the adrenergic nerves as revealed by histofluorescence.

Commercially available epinephrine (EPI) 2% and dipivalyl epinephrine (DPE) 0.1% ophthalmic solutions were instilled twice daily in the eyes of rats over a 12-week period and compared to placebo-vehicle-treated controls. Fluorescence photomicrographs of stretch preparations from the dilator muscle of the rat irises showed a weaker fluorescence in the eyes treated with EPI and DPE as compared with controls treated with a placebo vehicle. This study provides further evidence that EPI and DPE treatment can result in a chemical sympathectomy as has been described following topical application of 6-hydroxydopamine.


Use of the single-plate Molteno implant in refractory glaucoma.

During a 5-year period, 60 patients with uncontrolled glaucoma in one eye, who were considered to have a poor surgical prognosis with conventional drainage surgery, were treated with a single-plate Molteno implant. The surgery was performed in one operation and the tube tied with an absorbable suture in all cases. The overall follow-up was 20.3 +/- 11 months (range 3-60). A successful outcome (defined as an intra-ocular pressure < or = 21 mm Hg with or without treatment) was achieved in 56% of the 16 eyes with either aphakic or pseudophakic glaucoma, in 71% of the 14 eyes with uncontrolled glaucoma despite a previous filtering procedure, in 46% of the 13 eyes with traumatic glaucoma and in 64% of the 17 eyes with traumatic glaucoma and lens involvement. The visual acuity remained the same or better in 70% (42/60). Early complications of the surgery were transient and easily treated. Late complications included tube exposure in 3 (5%), tube retraction in 2 (3.3%), bleb encapsulation in 5 (8.3%) and corneal decompensation in 1 (1.65%). This study suggests that the single-plate Molteno implant is a useful drainage device with satisfactory results when used for the treatment of refractory secondary glaucoma.


Epidermal growth factor in topical treatment following epikeratoplasty.

The efficacy of epidermal growth factor (EGF) in reducing the healing time of the cornea after an epikeratoplasty has been evaluated in an open study in two groups of patients. The time required for complete reepithelialization of the cornea was recorded, and the data obtained were analyzed statistically. In the EGF group the reepithelialization was significantly faster than in the control group. These results indicate that EGF is effective in reducing the reepithelialization time of the cornea after an epikeratoplasty.


Effect of acetylcholine on intraocular pressure following small-incision cataract surgery.

40 patients, who underwent phacoemulsification and implantation of a polyHema intraocular lens (IOGEL-1103) were assigned to two groups. After evacuation of Healon from the capsular bag behind the lens and the anterior chamber, either 0.5 ml of 1% acetylcholine chloride or 0.5 ml of balanced salt solution was injected into the anterior chamber. When compared with preoperative values, the mean intraocular pressure (IOP) 6 h postoperatively was unchanged in the acetylcholine group (0 +/- 8.5 mm Hg) but increased in the control group (+4.1 +/- 7.4 mm Hg). 18 h postoperatively, the mean intraocular pressure slightly decreased in the acetylcholine group (-0.5 +/- 6.1 mm Hg) compared with an increase of +1.4 +/- 4.4 mm Hg in the control group. Intraocular pressure exceeding 25 mm Hg was observed at 6 h in 2 (10%) patients of the acetylcholine group and in 4 (20%) of the control group. At 18 h, intraocular pressure was elevated in only 1 (5%) patient of the acetylcholine group and in 3 (15%) of the control group. From these results, we conclude that the evacuation of Healon from the capsular bag behind the implanted lens and acetylcholine reduce the incidence of postoperative elevations of intraocular pressure.


Astigmatism after phacoemulsification and aspiration procedures: BENT versus standard incisions.

We examined the induction and spontaneous regression of corneal astigmatism among 1,023 phacoemulsification and aspiration (PEA) cataract surgeries performed with standard (n = 831) and BENT incisions (n = 192). The BENT (between 9 and 12 o'clock) incision is a method of entering the anterior chamber from the oblique side. In the BENT group, the degree of astigmatism was not significantly different from the standard group, 3 months postoperatively (1.48 +/- 0.07 vs. 1.25 +/- 0.04 dptr.) and 6 months postoperatively (1.30 +/- 0.06 vs. 1.28 +/- 1.28 +/- 0.06 dptr.). However, 1 week and 1 month postoperatively, the astigmatism resulting from the BENT incision was much less than that of the standard PEA incision (1.69 +/- 0.17 vs. 2.96 +/- 0.05 and 1.60 +/- 0.08 vs. 1.80 +/- 0.05 dptr, respectively). Visual acuity also improved faster. The BENT procedure is recommended, because it is a simple way to lessen astigmatism.


Long-term follow-up of dominant macular dystrophy with flecks (Stargardt).

We present a family with dominant macular dystrophy and flecks (Stargardt) which was followed for 20 years. Twenty-three subjects out of 48 members in 4 generations underwent fundoscopic examination. Nine asymptomatic patients had a few scattered, small, whitish, drusen-like changes in the posterior pole, and an additional patient had several clumps of increased pigmentation at the level of the retinal pigment epithelium in the macular region. Five patients had macular degeneration, with the onset of visual loss at between 24 and 30 years of age. The maculopathy started as fine, punctate, pigmentary changes, with transmission retinal pigment epithelial defects (as seen angiographically), or as flecks. The maculopathy progressed into a garland of perifoveal, subretinal flecks with small, central, areolar, chorioretinal atrophy. At the end-stage, there was a larger, central area of choroidal atrophy and a wider wreath of subretinal flecks. Visual acuity stabilized at the 20/200 level. Visual loss preceded clinically visible choroidal atrophy and was coincident with the accumulation of flecks in the foveal region.


[Papilledema and POEMS syndrome].

A new case of optic disk swelling associated with POEMS syndrome is described. This is a rare disease, but it should be suspected in cases of bilateral optic disk swelling when defining systemic components are present: polyneuropathy (P), organomegaly (O), endocrinopathy (E), monoclonal component (M) and skin changes (S). Usually visual acuity is maintained. However, loss of vision secondary to optic disk swelling and associated macular edema could be found.


Spontaneous orbital hemorrhage in adult females. A report of three cases.

Three cases of spontaneous orbital hemorrhages in 3 adult females are reported. All of the patients had acute radiating pain in the orbit, vomiting and proptosis with a limitation of motility and ecchymosis of the eyelids. One was due to a large orbital varix with a preceding history of intermittent exophthalmos; the causes of the other cases could not be determined from their backgrounds. Within a few weeks, all of them had recovered from hematoma and had good prognoses without surgery. Orbital venous bleeding with 40 mm Hg pressure will cause more than 500 g tension on the four rectus muscles. To treat this clinical emergency, hemostasis with compression in the early phase and waiting for its spontaneous absorption are recommended.


[Posner-Schlossman syndrome].

The clinical features of Posner-Schlossman syndrome and the various differential diagnoses are described in a 20-year-old patient. Additional to Posner-Schlossman syndrome this patient showed signs of Axenfeld's anomaly. He also presented symptoms of a status-dysrhaphicus-like state after atrial septal defect and the ability to overstrain the distal finger joints. Posner-Schlossman syndrome, heterochromic cyclitis, anterior-chamber cleavage syndrome and ICE syndrome (iridocorneal-endothelial syndrome: Chandler's, Cogan-Reese syndrome and progressive essential iris atrophy) often produce similar effects at the Descemet membrane, the anterior chamber angle and the iris. Because of the same mesodermal origin of these tissues we suggest that all the diseases mentioned above are merely different clinical expressions of one main disease.


Fisher's syndrome without total ophthalmoplegia.

A 16-year-old boy with acute ophthalmoplegic polyneuritis (Fisher's syndrome) exhibited bilateral internal ophthalmoplegia, but only lateral rectus and superior oblique eye movements were affected. Gaze-evoked nystagmus was also present on left lateral gaze. Pupillary reflex recovered 7 weeks after onset, but neither cholinergic supersensitivity nor light-near dissociation were present during the recovery process. This is the first such case to be reported in which the site of the lesion responsible for the pupillomotor impairment was the Edinger-Westphal nucleus.


Electrically evoked auditory brainstem responses in cochlear implant patients.

Electrically evoked auditory brainstem responses (EABR) were recorded in completely deaf patients implanted with Ineraid multichannel cochlear implants. Clear and reproducible EABR were obtained from all patients. Parametric differences with auditory brainstem responses (ABR) were demonstrated and can be explained by the different natures of both types of stimulations (electric versus acoustic). Evidence is given that other well-known properties of auditory evoked responses, like 'binaural interaction' or suppression of responses in a forward masking paradigm, can be observed in EABR of implanted patients.


Exploratory cochleotomy. Assessment of auditory nerve excitability and anatomical conditions in cochlear implant candidates.

The exploratory cochleotomy is a new diagnostic procedure for the selection of cochlear implant candidates. We use this procedure to assess the excitability of the auditory nerve, the patency of the cochlea and to detect undesirable side effects of electrical stimulation, such as facial nerve activation. The exploratory cochleotomy is a limited surgical procedure performed under local anesthesia in adults and light sedation in children. It is combined with the recording of electrically evoked brainstem responses elicited by an intracochlear probe electrode.


Digital speech processing for cochlear implants.

A rather general basic working hypothesis for cochlear implant research might be formulated as follows. Signal processing for cochlear implants should carefully select a subset of the total information contained in the sound signal and transform these elements into those physical stimulation parameters which can generate distinctive perceptions for the listener. Several new digital processing strategies have thus been implemented on a laboratory cochlear implant speech processor for the Nucleus 22-electrode system. One of the approaches (PES, pitch excited sampler) is based on the maximum peak channel vocoder concept whereby the spectral energy of a number of frequency bands is transformed into appropriate electrical stimulation parameters for up to 22 electrodes using a voice pitch synchronous pulse rate at any electrode. Another approach (CIS, continuous interleaved sampler) uses a maximally high pitch-independent stimulation pulse rate on a selected number of electrodes. As only one electrode can be stimulated at any instance of time, the rate of stimulation is limited by the required stimulus pulse widths (as determined individually for each subject) and some additional constraints and parameters which have to be optimized and fine tuned by psychophysical measurements. Evaluation experiments with 5 cochlear implant users resulted in significantly improved performance in consonant identification tests with the new processing strategies as compared with the subjects own wearable speech processors whereas improvements in vowel identification tasks were rarely observed. The pitch-synchronous coding (PES) resulted in worse performance compared to the coding without explicit pitch extraction (CIS).(ABSTRACT TRUNCATED AT 250 WORDS)


Experience with the cochlear miniature speech processor in adults and children together with a comparison of unipolar and bipolar modes.

Following the experience with nearly 150 patients with the Nucleus cochlear implant, a more sophisticated and lighter speech processor was tested successfully in terms of better speech understanding. In order to prepare further miniaturization, the standard bipolar stimulation mode was compared with an unipolar mode. It was found that unipolar stimulation needs less energy, without decreasing speech understanding. Preconditions for supplying very young children with a cochlear implant were the use of electrically elicited stapedius reflex thresholds, obtained intraoperatively, for the fitting of the speech processor and the setup of a special rehabilitation center, where children together with their mothers could be trained in hearing and understanding by special teachers and engineers for 12 weeks, distributed over the 1st postoperative year.


Geneva experience with the Ineraid multichannel cochlear implant.

Ineraid is a multichannel intracochlear implant of recent design that can provide high levels of speech recognition to totally deaf patients. We chose this device when it became available in 1985 because of our clinical and research interests. We had no commercial ties and could therefore critically assess the value of this implant in an array of patients, including congenital deafness, ossified cochleas and perilingual children.


Psychological adaptations and emotional observations of eight multichannel cochlear implant patients.

A pilot study was performed with 8 deaf patients who received the 'Ineraid' multichannel cochlear implant in Geneva, Switzerland. The mechanisms of psychological adaptation in these patients are summarized.


Case report: top hearing performances of a postlingually deaf cochlear implant user.

On the occasion of the Cochlear Implant Symposium in Geneva in October 1991, top hearing results attained by a young postlingually deaf woman with cochlear implant systems were presented in video recordings. These data are centered on demanding hearing performances in test situations and in a telephone conversation. For various reasons, two reimplantations were necessary in this deaf patient. Initially, she was provided with a single-channel extra-cochlear electrode of the Vienna type, which she found to improve her lipreading substantially, and she attained an unexpectedly good understanding of speech on a purely auditory basis. Today, this postlingually deaf women uses a multichannel intracochlear electrode of the Nucleus type. The excellent results with the first extracochlear system are clearly surpassed with the intracochlear system. Not least because of her above-average speech competence, the cochlear implant user attains a high degree of open speech understanding. Her verbal hearing efficiency is comparable to that of a person with mild to moderately severe hearing loss.


Autograft ossiculoplasty in cholesteatoma.

Although using autogenous ossicles in reconstruction offers stable hearing results with good tendency for healing and minimal extrusion, their use in cholesteatomatous ears has been criticized for the possibility of progressive osteitis, bone resorption and cholesteatoma recurrence. In the present study we have been investigating a way which affords safe re-implantation of such ossicles. Treatment by burring followed by autoclaving seems to offer an implant that is safe both bacteriologically and pathologically. We have found no evidence that cholesteatoma could develop from such treated ossicles.