Relative lipophilicities and structural-pharmacological considerations of various angiotensin-converting enzyme (ACE) inhibitors.

Lipophilicities of seven structurally diverse angiotensin-converting enzyme (ACE) inhibitors, viz., captopril, zofenoprilat, enalaprilat, ramiprilat, lisinopril, fosinoprilat, and ceronapril (SQ29852), were compared by determining their octanol-water distribution coefficients (D) under physiological pH conditions. The distribution co-efficients of zofenopril, enalapril, ramipril and fosinopril, which are the prodrug forms of zofenoprilat, enalaprilat, ramiprilat, and fosinoprilat, respectively, were also determined. Attempts were made to correlate lipophilicities with the reported data for oral absorption, protein binding, ACE inhibitory activity, propensity for biliary excretion, and penetration across the blood-brain barrier for these therapeutic entities. Better absorption of prodrugs compared to their respective active forms is in agreement with their greater lipophilicities. Captopril, lisinopril, and ceronapril are orally well absorbed despite their low lipophilicities, suggesting involvement of other factors such as a carrier-mediated transport process. Of all the compounds studied, the two most lipophilic ACE inhibitors, fosinoprilat and zofenoprilat, exhibit a rank-order correlation with respect to biliary excretion. This may explain the dual routes of elimination (renal and hepatic) observed with fosinoprilat in humans. The more lipophilic compounds also exhibit higher protein binding. Both the lipophilicity and a carrier-mediated process may be involved in penetration of some of these drugs into brain. For structurally similar compounds, in vitro ACE inhibitory activity increased with the increase in lipophilicity. However, no clear correlation between lipophilicity and ACE inhibitory activity emerged when different types of inhibitors are compared, possibly because their interactions with enzymes are primarily ionic in nature.


The development of a microwave fluid-bed processor. I. Construction and qualification of a prototype laboratory unit.

The static bed- and planetary-type microwave dryers currently available to process pharmaceutical materials are not designed to use hot-air fluidization for the purpose of maximizing microwave energy inputs and particle drying. To take advantage of the benefits offered by fluidization, a 1-kg Uni-Gatt laboratory fluid bed processor was modified to support microwave-assisted fluid bed drying of several representative pharmaceutical granulations. The construction, design features, and validation of this new microwave fluid bed processor are presented.


The development of a microwave fluid-bed processor. II. Drying performance and physical characteristics of typical pharmaceutical granulations.

Four typical pharmaceutical granulations were used to measure the enhanced drying performance of a laboratory-sized microwave fluid-bed processor, the design and construction of which were presented in Part I of this work (preceding paper). Results demonstrate improvements in observed drying rates by as much as sixfold depending upon the granulation type and drying conditions. At a low inlet temperature (30 degrees C), drying was achieved with microwave power inputs of 100-125 W/liter of working capacity, whereas similar targeted moisture levels were unattainable using conventional fluid-bed drying. Microwave energy available for heating and drying was 68 to 86% of the total microwave energy inputted.


Placental biopsy in the third trimester of pregnancy.

Forty-two women with abnormal ultrasound findings after 27 weeks' gestation underwent a placental biopsy. In 39 cases, a karyotype was obtained from a direct preparation within 48 h, five abnormal karyotypes being detected (four trisomies and a triploidy). One confirmed placental mosaic was also detected. In one case, a small terminal deletion of chromosome 7 was not detected at the time due to the quality of the preparation. A karyotype can be obtained from a direct preparation in the third trimester in over 90 per cent of cases, the quality of the preparation allowing the reliable detection of abnormalities of chromosome number. We believe that this technique may be usefully, reliably, and safely employed in the third trimester of pregnancy by those with an interest in antenatal ultrasound diagnosis who do not have immediate access to a cytogenetics laboratory and who feel that cordocentesis is inappropriate for their situation.


Genetic diagnosis by chorionic villus sampling before 8 gestational weeks: efficiency, reliability, and risks on 317 completed pregnancies.

Transabdominal chorionic villus sampling (TA-CVS) was attempted in 328 high-risk pregnancies at 6-7 weeks of gestation. Sampling was feasible in 97.7 per cent of cases; chorionic tissue specimens of more than 10 mg were obtained in 94.4 per cent of cases at the first needle insertion and in 100 per cent after a second attempt. Fetal karyotyping succeeded in 99.4 per cent of cases, while no diagnostic failures were reported in enzymatic and DNA analyses. Fetal loss rate in the first 4 weeks after CVS was significantly higher than in the later CVS series (7.2 vs. 2.5 per cent), but 50 per cent of losses were observed within 2 weeks in cases of inviable aneuploidies. A high incidence of severe limb abnormalities (1.6 per cent) was detected in pregnancies intended to continue, confirming the aetiological role of early CVS. Unclear visualization of the placental limits and poor control of the needle path are thought to be the main reasons for the vascular disruption of the chorionic plate, and thereby hypoxic embryo tissue damage. A better selection of cases, together with high-resolution vaginal ultrasound visualization, and analytical techniques requiring a minimal amount of tissue should avoid any teratogenic effect of early CVS.


Second-trimester maternal serum immunoreactive inhibin as a marker for fetal Down's syndrome.

We measured immunoreactive inhibin in the maternal serum of 80 pregnancies with a chromosomally normal fetus and ten Down's syndrome pregnancies in the second trimester. The inhibin level in all Down's syndrome pregnancies was above the normal median; the multiple of the normal median (MoM) was 1.9. We found a statistically significant difference between the levels of inhibin in unaffected and affected pregnancies (Kolmogorov-Smirnov test: p < 0.002). Using an arbitrarily chosen cut-off of 2.4 MoM, 40 per cent of Down's syndrome and 5 per cent of the normal pregnancies were found. We conclude that immunoreactive inhibin may be useful as a marker for fetal Down's syndrome.


Fumarylacetoacetase activity in cultured and non-cultured chorionic villus cells, and assay in two high-risk pregnancies.

We describe further development of the fumarylacetoacetase (FAA) assay for the prenatal diagnosis of tyrosinaemia type 1 using chorionic villus sampling (CVS). We have established a reference range for FAA activity in cultured villus cells and have confirmed previously reported data on the FAA activity in uncultured chorionic villus cells. This should allow confirmation of results using CVS, without the need for further invasive procedures. We report the FAA enzyme stability at -70 degrees C, +4 degrees C, and at room temperature, and we have shown no obvious difference in enzyme activity with gestational age. We have analysed cultured and non-cultured CVS activity of FAA in two pregnancies at risk of tyrosinaemia type 1. In both, the fetus was designated unaffected, and these results were confirmed postnatally.


Transabdominal chorionic villus sampling: fetal loss rate in relation to maternal and gestational age.

In this paper we report the fetal loss rate in relation to both maternal and gestational age in 1764 pregnant women who underwent transabdominal chorionic villus sampling (TA-CVS) between January 1986 and August 1990. The fetal loss rate, considered as a proportion of continuing pregnancies, decreased with advancing gestational age at sampling from 4.3 per cent before 9 weeks to 0.4 per cent at or after 13 weeks, the difference being statistically significant (p < 0.025). The fetal loss rate increased from 1.6 per cent in women under 30 to 2.4 per cent in women of 40 years or over, but the difference was not statistically significant. Considering that the total fetal loss rate before 28 weeks' gestation was on average 1.91 per cent (1.3 per cent under 35 years and 2.8 per cent in women of 35 or over), we believe that TA-CVS is a safe and effective technique for prenatal diagnosis of genetic diseases.


Effect of introducing prenatal diagnosis on the reproductive behaviour of families at risk for cystic fibrosis. A cohort study.

We studied 101 couples to determine how far their reproductive behaviour was affected by the diagnosis of cystic fibrosis (CF) on its first occurrence in the couple's progeny and by the availability of prenatal diagnosis (PD). The couples were all resident in the Veneto and Trentino regions and attending the Verona CF Centre. CF had been diagnosed in the first affected child, during the period 1 January 1980-1 July 1990, before the age of 1 year. Couples received a questionnaire regarding socio-demographic status, reproduction data, and awareness of PD. Reproductive history was divided into three phases: prior to diagnosis of CF in the first affected child; from this time until PD was made available; and after the couples had learned of PD. In phase 2 (awareness of the genetic risk but not of PD), 54 couples showed a marked decrease in reproduction, none of the few pregnancies that occurred being taken to term. When couples became aware of PD, some resumption of reproductive activity occurred and 11 per cent of the 101 couples had another child; PD was used in 65 per cent of pregnancies and the abortion rate decreased to 35 per cent. All couples who opted for PD had no children without CF.


Anencephaly in a fetus with osteogenesis imperfecta: early diagnosis by transvaginal sonography.

Early prenatal diagnosis of osteogenesis imperfecta at 14 weeks' gestation by transvaginal sonography is reported. An anencephalic fetus was found at autopsy, although on sonographic examination complete brain tissue had been observed. A possible explanation for these findings and theories on the pathogenesis of anencephaly are discussed.


Human chorionic beta-mannosidase: comparison with beta-mannosidase from human cultured fibroblasts.

The conditions for assay of beta-mannosidase activity in human chorionic villi (CV) were studied using the fluorogenic substrate 4-methylumbelliferyl-beta-D-mannopyranoside. A comparison of the biochemical properties of the CV beta-mannosidase with those of the enzyme from human cultured fibroblasts showed their similarity. Like the enzyme from skin fibroblasts, the CV beta-mannosidase had rather high activity. Both enzymes had virtually the same pH optimum (4.2-4.7) and Km value. The data presented suggest that chorion biopsy specimens can be used for prenatal determination of beta-mannosidase activity at an early stage of development.


Prenatal analyses in a pregnancy at risk for beta-mannosidosis.

Prenatal analyses were performed in the pregnancy of the mother of a patient with beta-mannosidase deficiency. Partial deficiency of beta-mannosidase activity in the chorionic villi indicated a heterozygous fetus and this first-trimester diagnosis was subsequently confirmed by amniocentesis.


Prenatal diagnosis for the cystic fibrosis mutation 1717-1, G-->A using arms.

A family carrying two cystic fibrosis mutations, delta F508 and 1717-1, G-->A, requested prenatal diagnosis. In order to eliminate the need for labelling of allele-specific oligonucleotides and to simplify the analysis, 1717-1, G-->A was detected using an ARMS (amplification refractory mutation system) method (Newton et al., 1989). Fetal DNA was obtained by chorionic villus sampling (CVS) and the ARMS technique was used to exclude the 1717-1, G-->A mutation. The fetus was found to be heterozygous for the delta F508 mutation. ARMS is a simple, quick, non-radioactive method suitable for detecting DNA mutations in various clinical situations.


Appearance of excessive lipids in amniotic fluid as a sign of fetal hyperlipidaemia.

The appearance of excessive lipids in amniotic fluid during Caesarean section raised the suspicion of a hyperlipidaemic fetus. The amniotic fluid had elevated cholesterol (53 mg/dl) and triglycerides (81 mg/dl). At the age of 2 months, the infant was hyperlipidaemic (cholesterol of 161 mg/dl and triglycerides of 84 mg/dl). The case suggests the possibility of prenatal diagnosis of hyperlipidaemia, a major risk factor for atherosclerosis.


[The current role of thoracoplasty in treatment of chronic pleural empyema].

To demonstrate the indication for surgery, the preoperative and postoperative course, and to assess the influence of thoracoplasty on respiratory physiology, the data of patients subjected to thoracoplasty during the past 30 years at our hospital were evaluated. Final assessment was performed separately for patients with and without preceding pulmonary resection. In 21 cases there was an unspecific empyema of the pleura and in 6 cases a specific one; in 14 cases there was also a concomitant bronchopleural fistula. After a washing-out period of 92 days (24-283) and after surgery had been unsuccessful in 9 patients, standard thoracoplasty was performed, complemented by a "jalousie" ("Venetian blind") plasty after Heller. Postoperative lethality was 11.1%. 5 patients developed pleuro-cutaneous fistulas that healed by local treatment; in one patient, a small residual cavity remained that required an additional plasty for correction. In 94% of the patients who had been operated upon, scoliosis occurred convex to the thoracoplasty; this was more marked in patients in whom lung resection had been performed than in patients without resection. Restrictive ventilatory disorders were seen in the lung function of 55% of the patients, whereas mixed restrictive-obstructive disorders occurred in 45%. Ergospirometry resulted under load besides in an increased respiratory minute volume (AMV), in a proportionate dead space of the AMV which was significantly higher than preoperatively. Despite the considerable functional and aesthetic consequences resulting therefrom, thoracoplasty still has its justification in refractory pleura empyemas as an ultimate means of cleaning up.


[Modification of pediatric lung function measurement by antibacterial filters].

The risk of cross-infection by contaminated lung function equipment can be reduced by the use of antibacterial filters. These filters, however, should have no significant influence on flow measurements. We investigated the effect of a new filter (Pall PF 30) on lung function measurements in 92 children and adolescents with bronchial asthma and cystic fibrosis. In randomized sequence, flow-volume curves and spirometry were registered in the whole body plethysmograph. Values measured with filter correlated closely to those registered without; individual values remained close to the line of identity. With high flow rates, however, there was a minimal tendency towards lower measurements with filter; this damping effect was flow-dependent and remained of a clinically insignificant dimension.


[Enzymes of a bacteriolytic lysoamidase preparation. Various properties of bacteriolytic protease L2].

Bacteriolytic proteinase L2 is able to cleave fluorogenic synthetic tripeptide anthranoyl-alanyl-alanyl-phenylalanyl-nitroanilide (Abz-Ala-Ala-Phe-pNA) at the bond between phenylalanine and p-nitroaniline. Optimal conditions of the tripeptide cleavage have been determined: pH 6.7 + 0.1; mu = 2 (by NaCl); t = 40 degrees C; KM = 2.6 x 10(-5) M. Metal cations reduced the enzyme activity. The enzyme was inhibited by EDTA, p-CMB, DIF. The synthetic tripeptide can be used to determine the activity of the L2 enzyme.


[Coincidence of lung diseases caused by Mycobacterium fortuitum and esophageal achalasia--case report and review of the literature].

We report on a case of lung infection due to mycobacterium fortuitum in conjunction with esophageal achalasia. A review of literature and a discussion on pathophysiological, clinical and therapeutical aspects are included. We conclude that bacterial poly-resistance in case of infections resembling tuberculosis should prompt a search for atypical mycobacteria. Patients suffering from nontuberculous mycobacteriosis of the lung should be subject to oesophageal examination.


[Enzymatic conversion of torulene and torularhodine into retinal].

The enzymatic conversion of torulene to retinal is demonstrated in in vitro tests using beta-carotene 15,15'-dioxygenase (EC 1.13.11.21) from the rabbit small intestine mucosa. This is the first evidence for the potent vitamin A activity of torulene. Little amounts of retinal also formed from methyl ester of torularhodin and from torularhodin.


[The effect of flupirtine on respiratory drive in healthy probands and patients with various lung diseases].

We investigated the effect of a novel analgesic compound, flupirtine on the respiratory center in 8 healthy controls and patients with lung emphysema (n = 6), bronchial asthma (n = 7) and lung fibrosis (n = 5). All patients received a in a double blind, randomized fashion on three separate study days 100 mg and 200 mg flupirtine and placebo, respectively. Respiratory drive was estimated from measurements of CO2-rebreathing curves and mouth occlusion pressure at rest and during CO2-rebreathing performed before, 1.5 and 3 hours after medication. We were unable to detect any significant depression of respiratory drive neither in the controls nor in the patients and therefore suggest that flupirtine is a safe analgetic compound even in patients with severe obstructive and restrictive lung function impairment.


[Sorption of enzymes on ion exchange resins of various structure].

The isothermic adsorption of microbial and animal enzymes on carboxyl and sulpha-cation exchange resins was studied. The adsorption isotherms are curves with a maximum. The adsorption of alpha-amylase was studied in the presence of organic solvents. It was found that organic solvents influenced the isothermic adsorption of alpha-amylase, which is associated with changes in the interactions between protein molecules in solution. The adsorption system was in equilibrium in all the cases.


[Aortopulmonary fistula formation after operation of aortic isthmus stenosis as a rare cause of recurrent hemoptysis].

An aneurysm of the aorta with aortobronchial fistula formation was seen in a 33 year old patient as a rare cause of recurring hemoptysis. 18 years previously he had undergone surgery of coarctation of the aorta. By means of different imaging methods the diagnosis was established in time and the aneurysm resected, so that the patient survived this mostly fatal incident.


In vivo and in vitro magnesium effects on aortic prostacyclin generation in DOCA-salt hypertensive rats.

To investigate the blood pressure lowering effect of magnesium (Mg2+) in the hypertensive rat, we measured the prostacyclin release (PGI2, as immunoreactive 6-keto-PGF1 alpha) by isolated aortae from normotensive and deoxycorticosterone acetate (DOCA)-salt hypertensive rats fed a control or Mg(2+)-enriched diet. We also studied the in vitro effect of Mg2+ on aortic PGI2 release. The Mg(2+)-enriched diet significantly decreased by 10% blood pressure in DOCA-salt hypertensive rats but not in normotensive rats. The Mg(2+)-enriched diet significantly increased by 122% aortic PGI2 release in DOCA-salt hypertensive rats, but not in normotensive rats. Mg2+ supplementation in the incubation medium (4.8 mM) significantly increased aortic PGI2 release by 94% in DOCA-salt hypertensive rats, but not in normotensive rats. These data suggest that the Mg(2+)-induced attenuation of blood pressure in DOCA-salt hypertensive rats could be linked with the enhanced vascular PGI2 release.


Influence of N-phenyllinoleamide from toxic oil samples on the lipoxygenase metabolism of exogenous arachidonic acid in mouse peritoneal macrophages.

N-phenyllinoleamide (NPLA) is a useful marker for adulterated oil samples associated with cases of toxic oil syndrome (TOS). To date, NPLA has not reproduced the human poisoning episode in experimental animal models and, thus, its pathological role in the syndrome remains controversial. The present report describes the effect of NPLA on the lipoxygenase metabolism of exogenous arachidonic acid (AA) in mouse peritoneal macrophages (MPM). Results show that MPM cells exposed to 1mM NPLA for 2 h, when subsequently incubated with exogenous 3H-AA, undergo a significant increase in the biosynthesis of 3H-12-hydroxyeicosatetraenoic acid (3H-12-HETE) whereas levels of 3H-15-HETE are relatively stable. These data indicate that NPLA selectively potentiates the lipoxygenase metabolism of exogenous AA, supporting the possible implication of lipid peroxidative processes in the ethiopathology of TOS, although the relatively high NPLA concentration required 'in vitro' makes it unlikely that this xenobiotic could be directly related to human toxicity.


Effect of sodium loading (3% NaCl) on arachidonic acid biosynthesis in rat liver microsomes.

Sodium loading increases arachidonic acid (AA) metabolism by way of the prostaglandins(PGs) from series 2. Its effect on AA biosynthesis remains unknown. The purpose of the present study was to investigate the influence of sodium loading on the fatty acid composition of liver and liver microsomes, and the liver microsomal delta-6 and delta-5 desaturations of linoleic acid (LA) into AA. We found a decrease of LA and dihomo-gamma-linolenic acid (DGLA) levels in liver total lipids of Wistar rats receiving hypernatriuretic drinking water (NaCl 3%) for 60 days. At the same time AA increased. DGLA decreased and AA increased in liver microsomal total lipids. 1(14) C-LA delta-6 desaturase and 2(14) C-DGLA delta-5 desaturase activities increased in liver microsomes. These results show that, in addition to its influence on the regulation of glomerular filtration, sodium loading is involved in the regulation of liver AA biosynthesis.


Regional differences of phospholipase A2 activity in the rabbit oviductal epithelium.

To evaluate the biosynthesis of prostaglandins in the oviducts, phospholipase A2 (EC 3.1.1.4) activities were first measured in the epithelial cells obtained from rabbit oviducts. At least four kinds of phospholipase A2 (PLA2) activities with respect to calcium dependency and pH requirement were observed. There were two calcium-dependent, pH optima of 7.5 and 8.5 activities, and two calcium-independent, pH optima of 4.0 and 8.0 activities. One of those activities, a calcium-dependent and alkaline active PLA2 activity of the epithelial cells was then compared between the ampullary portion and the isthmic portion of the oviducts. The activity was significantly higher in the ampullary epithelium than in the isthmic epithelium (223.2 +/- 57.2 or 103.8 +/- 32.3 pmol/min/mg, p < 0.05). These results support the idea that the production of prostaglandins, which is dependent upon the activity of the arachidonate cascades, was higher in the ampullary portion of oviduct than that in the isthmic portion. The PLA2 activity of the ampullary epithelium may thus play an important role in the regulation of smooth muscle contractility and ciliary movement.


Effect of heat inactivation and freezing on fatty acid composition of plasma and red blood cells.

The effect of heat inactivation and freezing on fatty acid composition of plasma and red blood cells was investigated. Analysis was completed at baseline; after freezing; after incubation; after incubation and subsequent freezing; after incubation, freezing and a second incubation; and after freezing and subsequent incubation. There were changes in fatty acid levels observed in all groups with the phospholipid fractions showing the greatest changes. Those bloods that had been incubated, frozen and incubated again, and those which had been frozen initially followed by incubation showed the greatest change when compared to baseline samples. Even though there were changes in fatty acid levels seen in all groups, the changes were small except in those two groups. Treatment of blood with either of those two treatment regimens changes the fatty acid values so that they do not accurately reflect the composition of fatty acids in the blood.


Calcium-dependent prostaglandin biosynthesis by lipopolysaccharide-stimulated rat Kupffer cells.

Isolated rat Kupffer cells produced and released prostaglandin (PG) E2, 6-keto-PGF1 alpha, and thromboxane B2 (TXB2) in response to lipopolysaccharide (LPS) stimulation. This elevation of PGE2, 6-keto-PGF1 alpha and TXB2 in the medium was not observed when cells were cultured in the absence of extracellular calcium or in the presence of an extracellular calcium chelator, EGTA. An intracellular calcium antagonist, TMB-8, also suppressed the production of PGE2, 6-keto-PGF1 alpha and TXB2 in a concentration-dependent manner. The intra-cellular calcium concentration of Kupffer cells elevated early after the addition of LPS determined by the use of fura-2 and a fluorescence microscopy. Moreover, calmodulin inhibitors, W-7 and W-13, apparently inhibited the production of PGF2, 6-keto-PGF1 alpha and TXB2. All these results suggest that LPS-induced PG production by stimulated rat Kupffer cells may be regulated by a calcium-calmodulin pathway.


Inhibition by protein kinase C activation of melittin-induced arachidonic acid release in PC12 pheochromocytoma cells.

In rat PC12 pheochromocytoma cells, melittin, a phospholipase A2 activator, stimulated the release of arachidonic acid in a dose-dependent manner in the range between 0.1 and 1 microM. 12-O-Tetradecanoylphorbol-13-acetate (TPA), a protein kinase C-activating phorbol ester, inhibited the melittin-induced release of arachidonic acid dose-dependently in the range between 0.1 nM and 0.1 microM, whereas 4 alpha-phorbol 12, 13-didecanoate, which is inactive for protein kinase C, was ineffective in this capacity. Staurosporine, a protein kinase C inhibitor, recovered the inhibitory effect of TPA on the melittin-induced release of arachidonic acid. These results suggest that the activation of protein kinase C inhibits phospholipase A2 activity in PC12 pheochromocytoma cells.


Acute effects of a single ethanol injection on in vitro rat uterine spontaneous motility, on uteri prostaglandin production and on tissue metabolism of triglycerides.

The acute effects of ethanol (ETOH), injected at 3 g.kg-1i.p. on spontaneous contractions, on prostaglandin (PG) production and on the metabolism of triglycerides (TGs), have been studied in uterine strips obtained from rats at diestrus and suspended in glucose-containing or glucose-free solution. The absolute values of isometric developed tension (IDT: expressed in mg) recorded at 0 time (initial or post isolation determinations) and the frequency of contraction (FC), expressed as the number of contraction cycles during 20 min, were similar for uterine strips from controls and from ETOH treated rats. The uterine IDT and the FC expressed as percent changes from internal controls (0 time values) were explored during 180 min in uteri suspended in glucose medium. The magnitude of IDT decreased, as time progressed, both in controls as well as in ETOH-treated rats. Afterwards, uterine strips from controls exhibited a partial recovery of their contractile activity. This pattern of recovery was not observed in uterine strips from ETOH-treated rats. The uterine IDT, in the ETOH-injected animals after 180 min of activity, were significantly smaller than those of controls. On the other hand, the FC decreased progressively up to the end of the experimental period both in controls as well as in ETOH-treated rats. In glucose-free medium, the IDT of uterine strips from ETOH-injected animals diminished significantly more than controls from 100-180 min following isolation and mounting. In addition, the FC of uterine strips from the ETOH group of rats were significantly smaller than in controls suspended in glucose-free solution.(ABSTRACT TRUNCATED AT 250 WORDS)


Inspiratory timing regulation of PGF2 alpha in newborn pigs.

In intact and vagotomized anesthetized, spontaneously breathing piglets, we investigated the regulation of inspiratory timing evoked by i.v. administration of prostaglandin (PG) F2 alpha. The inspiratory time was evaluated from the flow trace as an index of mechanical inspiratory time (Ti) and from costal and crural diaphragmatic EMG (TiEMG) as an index of neural inspiratory time. Our results under control conditions showed that TiEMG was shorter than Ti. Vagotomy abolished the difference, inducing a change in the power spectrum without modifying the centroid frequency (Cf). PGF2 alpha lengthened TiEMG, causing a postinspiratory diaphragmatic discharge to appear, while mechanical inspiratory time decreased significantly. Postvagotomy i.v. administration of PGF2 alpha did not cause any significant changes in inspiratory time and did not evoke the postinspiratory discharge. The i.v. administration of PGF2 alpha before and after vagotomy did not change the centroid frequency in spite of recruitment of new motor units synchronized with those that are active under control conditions.


Cytokine modulation of immune activation associated suppression of macrophage cyclooxygenase activity in vivo.

Intraperitoneal infection with Listeria monocytogenes (LM) results in activation of the peritoneal macrophage population which displays increased surface expression of major histocompatibility (MHC) Class II (Ia) antigen and markedly suppressed prostaglandin (PG) synthesis. We demonstrate here that this decrease in PG production is also seen after treatment by mitogen (Con A) and endotoxin (LPS), and can be explained by reduced cyclooxygenase activity in these cell populations. We show that, whereas Ia expression was augmented at all doses of LM and Con A tested, it displayed a biphasic response to LPS in vivo: increase at the lowest dose and inhibition at higher doses. In order to identify possible endogenous mediators of these responses, we used highly purified preparations of recombinant murine (rMu) cytokines and neutralizing cytokine specific monoclonal antibodies (MAbs) to examine whether interferon-gamma (IFN-gamma) and/or tumor necrosis factor (TNF) down-regulate macrophage cyclooxygenase activity in vivo. We found that IFN-gamma induced Ia expression but had no effect on PG secretion. In contrast, TNF-alpha suppressed PG synthesis and inhibited Ia surface expression. Similarly, in our model of Con A-induced peritoneal macrophage activation, pretreatment of animals with a neutralizing MAb to rMuIFN-gamma completely blocked the induction of Ia positive macrophages by Con A but did not affect Con A-dependent suppression of PG synthesis. Pretreatment with MAb to TNF had no effect on Con A-induced Ia levels, but significantly inhibited suppressed PG synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)


Effect of administration of an analog of LHRH on appetitive learning in young and middle-aged female rats.

Hypothalamic luteinizing hormone-releasing hormone (LH-RH) had been reported to induce changes in defensive learning. In middle age, females exhibit a decline in their reproductive axis. Several studies in rodents suggested that hypothalamic LHRH function deteriorated in middle-aged females. Our experiments compare T-maze learning in young and middle-aged female rats and study the effect of administration of an analog of LHRH, D-Trp6-LHRH. The ovarian action of the analog was studied and a gonadectomized control group was added. No differences were observed between young and middle-aged females in acquisition, retention, and reversal of a simple discrimination in the T-maze. However, after removal of motor and spatial cues acquisition of the discrimination on visual cues was impaired in middle-aged females compared to young mature ones. Administration of D-Trp6-LHRH enhanced performance during the visual discrimination in younger females and had no action in middle-aged ones, whereas it inhibited ovary function in both groups. Ovariectomy had no effect. These results suggest a direct effect of the analog of LHRH on the CNS and show that this peptide fails to counteract the deleterious effect of age on performance.


Rats bred for differences in preference to cocaine: other behavioral measurements.

Cocaine has repeatedly been shown to produce conditioned place preference (CPP) in the rat. The present study employed the heterogenous N/Nih rat stock to produce a selectively bred rat line determined by individual place preference to a conditioning dose of 2.5 mg/kg cocaine. As each of three generations of rats were exposed to the CPP task, cocaine-preferring (CP) males were mated with CP females whereas cocaine-nonpreferring (CNP) male rats were paired with their female counterparts. Rats in litters of the third generation of these selectively bred rats were used in two collateral studies: one involving the discriminative stimulus properties of cocaine and the other to investigate the ability of cocaine to stimulate activity. Results indicate that the continued breeding of CP animals has resulted in rats that prefer cocaine, whereas the breeding of CNP rats is defining a line of rats that actually find cocaine aversive. In testing the discriminative stimulus performance of five male CP and five male CNP rats, the learning rates and dose-response relationship to cocaine were not significantly different between these two groups. In contrast, administration of 5.0 and 7.5 mg/kg cocaine to male and female CP and CNP rats indicated that, although all groups were stimulated by cocaine when compared to vehicle administration, male CNP rats showed a significantly decreased reaction to these two doses of cocaine. The possibility that conditioned place preference and locomotor stimulation are subserved by the same neural substrates, that is, most probably the dopaminergic systems in the nucleus accumbens of the brain, is discussed.


Effects of methadone on free feeding in satiated rats.

A variety of opioids and opiates are known to increase short-term food intake. In the present study, we evaluated the effects of methadone on free feeding in satiated rats. We assessed the effect of methadone (0, 1.5, 3.0, 5.0, and 10.0 mg/kg) on food intake 1, 2, 4, and 6 h after injection for 3 consecutive days. Two hours after methadone administration, food intake was inversely related to dose, but after 6 h a direct relationship between dose and feeding was obtained. Food intake increased with repeated methadone administration. In Experiment 2, methadone (5.0 mg/kg) was injected and food was made available 0, 1, 2, or 3 h later. Maximal food intake occurred in the third and fourth hours following methadone administration. As in Experiment 1, food intake increased with repeated methadone administration. Increases in food intake following repeated methadone administration may have been due to the development of tolerance to effects of methadone that may interfere with feeding, such as sedation. In Experiment 3, methadone was administered daily or every fifth day, assuming that spacing injections would retard tolerance development. Repeated daily methadone administration was associated with increased food intake earlier in the session, whereas increases in food intake following spaced methadone administration occurred later in the session. These data indicate that methadone increases short-term feeding in satiated rats. This is in contrast to the reported decrease in food-reinforced behavior noted in operant studies. This contrast may be due to sedating or other disabling effects of methadone.


Yohimbine attenuates clonidine-induced feeding and macronutrient selection in genetically obese (ob/ob) mice.

Biochemical abnormalities in the hypothalamus of the genetically obese (C57B1/6J, ob/ob) mouse, including increased levels of endogenous norepinephrine (NE) in the paraventricular nucleus (PVN) and reduced medial hypothalamic NE metabolism, have been cited as evidence of a CNS defect contributing to altered caloric intake in this genetic strain. In the current study, the alpha 2-antagonist yohimbine (YOH) and the alpha 2-agonist clonidine (CLON) were administered systemically to 6-h meal-feeding obese and lean mice. Yohimbine (3-5 mg/kg, IP) significantly reduced total energy intake and intake of carbohydrate and fat, in both phenotypes, without altering protein intake. In contrast, CLON (25 micrograms/kg, IP) potentiated feeding, resulting in a shift in macronutrient selection toward a significant increase in the proportional intake of carbohydrate. Obese mice, however, showed an enhanced behavioral response to CLON injection. Pretreatment with 1 mg/kg YOH, a dose that alone did not significantly alter energy intake or diet selection, blocked CLON's stimulatory effect on feeding and carbohydrate preference. These results are consistent with a role for alpha 2-noradrenergic receptors in appetite regulation of ob/ob and lean mice and suggest that disturbances in this system may be involved in the development of genetic obesity.


Effects of L-tyrosine on mixed-acting sympathomimetic-induced pressor actions.

We previously reported the ability of L-tyrosine (L-TYR) to potentiate the anorectic activity of various mixed-acting sympathomimetics including [R*S*]-(+/-)-norephedrine [phenylpropanolamine (PPA)], [1R,2S]-(-)-ephedrine (EPH), and [S]-(+)-amphetamine (AMPH) in hyperphagic rats. Included in those studies was the attenuation of L-TYR's effect when coadministered with L-valine, a large neutral amino acid that competes with L-TYR for uptake into the brain, suggesting a central locus for the action of L-TYR. Additional studies demonstrated the inability of L-TYR to alter the peripherally mediated PPA-, EPH-, and AMPH-induced increases in gastrointestinal transit time and retention and intrascapular brown adipose tissue thermogenesis. Because the mixed-acting sympathomimetics are known to increase blood pressure, these studies examined the ability of L-TYR to influence the pressor responses to PPA, EPH, and AMPH (0.03-1 mg/kg) in urethane-anesthetized rats. Each of the mixed-acting sympathomimetics significantly increased mean arterial, systolic, and diastolic blood pressures when administered alone, but no potentiation by L-TYR was observed. These results demonstrate the inability of L-TYR to potentiate the peripheral vasopressor effects of PPA, EPH, and AMPH. These data, in conjunction with our previous findings, suggest that the potentiation by L-TYR of the mixed-acting sympathomimetics is largely restricted to centrally mediated responses.


Effects of nicotine on activity and stress-induced gastric ulcers in rats.

Nicotine is known to influence locomotor activity. The alkaloid also intensifies gastric ulcer formation in stressed rats. The effects of nicotine on locomotor activity in relation to gastric lesions induced by restraint at 4 degrees C for 2 h (stress) were, therefore, studied. Ten-day treatment with nicotine 25 or 50 micrograms/ml drinking water potentiated stress-evoked ulceration and mast cell degranulation. These same doses of nicotine increased vertical motor activity; only the higher dose of the alkaloid enhanced horizontal movements. Phenobarbitone (12.5, 25, or 50 mg/kg, SC) dose dependently reduced vertical activity, as well as stress-induced gastric ulceration and mucosal mast cell degranulation. The drug also lessened the potentiating effects of nicotine on motor activity and stress-evoked gastric lesion formation. It is concluded that the ability of chronic nicotine treatment to intensify stress-induced gastric ulceration most likely owes part of its action to a mechanism evoking increased activity, which possibly reflects an influence on the CNS, as well as to enhancement of mast cell degranulation in the stomach glandular mucosa.


Effects of prenatal exposure to cocaine on the rest-activity cycle of the preweanling rat.

Either 45 or 60 mg/kg cocaine HCl was administered from days 8-22 of gestation. Pair-fed and nontreated groups served as controls and all treated and control litters were fostered at birth to untreated dams. To examine whether cocaine produces effects on the rest-activity cycle of the offspring, groups of three littermates from each of the treated and control groups were tested for an 8-h observation period on electronic activity monitors at 22 days of age. Neither activity level nor the rest-activity pattern were affected by cocaine. These findings are discussed in relation to previous studies of cannabis and methadone effects on the rest-activity measure.


Opioid modulation of thermal dehydration-induced thirst in rats.

Male Sprague-Dawley rats were utilized to study the effects of the opioid receptor antagonists, naloxone and naltrexone, on thirst induced by thermal dehydration. In an initial experiment, the depressant effect of naloxone (1.0 mg/kg, IP) on the water intake of rats deprived of water for 24 h was confirmed. In subsequent experiments, rats were thermally dehydrated by exposing them without water to a 40 degrees C environment for 1-4 h. Following heat exposure, rats were injected with either naloxone or naltrexone either IP or ICV. Fifteen minutes later, rats were provided with water and water intake was measured for 2 h. Both naloxone and naltrexone had dose (0.1-5.0 mg/kg, IP)-dependent effects of reducing water intake of rats thermally dehydrated for 3 h. Water intake of rats thermally dehydrated for 2 or 4 h was also attenuated by pretreatment with naloxone. Rats thermally dehydrated for 3 h exhibited decreases in water intake following ICV injection of either naloxone or naltrexone at a dose of 50 micrograms. Neither naloxone nor naltrexone had an effect on urine output in any experiment. The water intake data support the hypothesis that thirst induced by thermal dehydration in rats is modulated by an opioid mechanism.


Behavioral and enzymatic interactions between benzyl alcohol and ethanol.

Acute IP injection of benzyl alcohol but not benzaldehyde (0.5 g/kg) caused aversion to voluntary drinking of 5% ethanol solution by male rats with preference to ethanol. Benzyl alcohol noncompetitively inhibited hepatic alcohol dehydrogenase of rats maintained for a short term on 5% ethanol compared to control. The results suggest an adverse interaction between benzyl alcohol and ethanol underlying the observed aversion to ethanol.


Deprenyl alters behavior and caudate dopamine through an amphetamine-like action.

In vivo microdialysis was used to concurrently measure the behavioral and caudate dopamine (DA) responses to the alleged irreversible type B monoamine oxidase inhibitor deprenyl. The effects were contrasted to those of the type A monoamine oxidase inhibitor, clorgyline. Consistent with its effects as an irreversible monoamine oxidase inhibitor, clorgyline produced an increase in DA concentration that remained elevated for at least 6 h. In contrast, the deprenyl-induced elevation in DA concentration occurred more rapidly, achieved a higher peak response, and then returned to baseline within 2 h following drug administration. The two drugs also produced distinctive changes in DA metabolite levels. Whereas the pattern of clorgyline-induced effects were consistent with irreversible monoamine oxidase inhibition, deprenyl produced an amphetamine-like response profile. Further, deprenyl but not clorgyline significantly increased locomotor activity. These results suggest that deprenyl does not augment caudate DA levels through monoamine oxidase inhibition. Rather, the pattern of its effects on caudate DA dynamics and behavior supports previous evidence that deprenyl produces its effects through its metabolism to amphetamine-like substances.


Severity of experimental allergic encephalomyelitis in rats depends upon the temporal contiguity between limbic seizures and inoculation.

Limbic seizures (forepaw clonus) were induced in Lewis rats by subcutaneous injections of lithium (3 mEq/kg) followed 24 h later by a muscarinic agent. Either 7 days before, 7 days after, or on the day of seizures, rats were inoculated with a spinal cord preparation. Other groups received these preparations but served as treatment (no seizure) controls. In three separate experiments, rats in which seizures had been induced at the time of inoculation displayed significant increases in the severity of clinical symptoms 14-20 days later relative to controls while rats in which seizures had been induced 7 days after inoculation displayed less severe symptoms; the latter effect was partially simulated by multiple injections of 1 mg/kg dexamethasone. The immunofacilitation effect was much stronger than the immunosuppression and explained 25-30% of the variance in the clinical severity scores.


Blocking naloxone-precipitated withdrawal in rats and hamsters.

Three experiments studied the effects of putative antagonists of opiate withdrawal in hamsters and rats. In Experiment 1, the calcium channel antagonists verapamil (20 mg/kg) and nifedipine (20 mg/kg) failed to antagonize naloxone (1 mg/kg)-precipitated withdrawal in hamsters implanted with two 75-mg morphine pellets, whereas clonidine (0.4 mg/kg), the alpha 2-adrenergic agonist, blocked most withdrawal signs. In Experiment 2, clonidine (0.4 mg/kg) and verapamil (20 mg/kg) were tested against naloxone-precipitated withdrawal in hamsters made acutely dependent by a single injection of morphine (15 mg/kg). As in Experiment 1, clonidine but not verapamil was effective. In Experiment 3, the effects of verapamil on naloxone-precipitated withdrawal were studied in morphine-pelleted rats and hamsters. In rats implanted with two morphine pellets, verapamil (20 mg/kg) reversed naloxone-precipitated withdrawal. By contrast, in hamsters implanted with either one or two morphine pellets neither of two doses of verapamil (20 and 30 mg/kg) was effective. These results are discussed in terms of species' differences in sensitivity to calcium channel blockers.


Discriminative stimulus properties of substituted amphetamine derivatives.

Animals were trained to discriminate amphetamine (1 mg/kg) from saline in a fixed-ratio (FR 10), food-reinforced paradigm. Amphetamine-appropriate responding was engendered by the training dose, and by 3 mg/kg, while at lower doses there was a progressive decrease in the extent of responding on the drug-appropriate lever. The following three novel amphetamine derivatives were tested for their ability to produce amphetamine-appropriate responding: 2,5-dimethoxy-4-ethoxy-amphetamine (DMEA); 2,5-dimethoxy-4-methylthio-amphetamine (DMMTA), and 2,4,5-trimethoxy-amphetamine (TMA). DMEA produced only minimal (< 20%) amphetamine-appropriate responding over a dose range of 0.1-10 mg/kg. Substantial decreases in response rate limited testing of the other amphetamines to a dose maximum of 3 mg/kg, but over the range of 0.1-3.0 mg/kg there was little evidence for generalization. At 3 mg/kg of either DMMTA or TMA, only 2 of 10 animals completed at least one uninterrupted FR 10 on either lever, and with either compound only 1 of these 2 animals responded more than 50% on the drug-appropriate lever. Of the three compounds tested, DMMTA had the greatest response rate-decreasing effect.


Antinociceptive properties of tiletamine-zolazepam improved by addition of xylazine or butorphanol.

A combination of tiletamine HCl and zolazepam HCl is frequently used as an anesthetic, but little is known about the antinociceptive properties of tiletamine-zolazepam. The antinociceptive properties of tiletamine-zolazepam alone or combined with xylazine or butorphanol were determined in the adult male rate using the tail-flick test. Changes in tail-flick latency were determined at 15, 45, and 75 min after IP drug administration of sterile water, sodium pentobarbital, morphine, tiletamine-zolazepam, xylazine, butorphanol, and tiletamine-zolazepam plus xylazine or butorphanol. Tail-flick latency approximated 100% maximum possible effect (MPE) at 15-75 min postinjection in morphine-treated rats. Tiletamine-zolazepam, xylazine, and butorphanol alone, at any dose utilized, produced less than 50% MPE. However, the combination of tiletamine-zolazepam with butorphanol or xylazine increased tail-flick latency approximately three times greater than tiletamine-zolazepam alone. These results demonstrate that: a) consonant with earlier findings, analgesia and anesthesia are independent states; b) tiletamine-zolazepam is not an effective combination with respect to analgesia; but c) in concert with appropriate drugs, it can exhibit potent antinociceptive properties.


Cocaine and GBR12909 produce equivalent motoric responses at different occupancy of the dopamine transporter.

The motoric-stimulating effect of dopamine (DA) reuptake blockers is thought to result from the increase in synaptic dopamine levels, which occurs as a consequence of blockade of DA reuptake. The present study tested measured occupancy of the DA transporter in vivo produced by behaviorally equivalent doses of the DA reuptake blockers GBR12909 (20 mg/kg), cocaine (20 mg/kg), WIN35-065-2 (1 mg/kg), and nomifensine (5 mg/kg). Two methods were used to measure in vivo occupancy of the DA transporter: a) an ex vivo method, in which the ability of whole brain supernatants, prepared from rats administered the test drugs, were tested for their ability to inhibit the reuptake of [3H]DA by striatal synaptosomes; and b) an in vivo binding assay using [3H]N-[1-(2-benzo(b)thiophenyl)cyclohexyl]piperidine ([3H]BTCP) to label the striatal DA transporter in vivo. Considerable data support the notion that this measurement is predictive of transporter occupancy in the nucleus accumbens. Similar results were obtained with both methods: The order of potency for apparent transporter occupancy was GBR12909 >> nomifensine > WIN35-065-2 = cocaine. These data indicate that it takes greater occupancy of the DA transporter by GBR12909 to produce behavioral effects equivalent to those produced by cocaine at lower transporter occupancy. The data of the present study suggest, therefore, that studies relating the effects of DA reuptake inhibitors on DA-mediated motoric behaviors to DA transporter occupancy might facilitate the identification of novel compounds potentially useful for the pharmacotherapy of cocaine abuse.


Relation of rotation to egocentric and allocentric spatial learning in the rat.

In this experiment, we asked whether the relation between amphetamine-induced rotation and the learning and retention of left-right discrimination extends to allocentric spatial learning or is limited to egocentric spatial tasks. Rotation was established following injections of d-amphetamine sulfate, and rats were classified as nonrotators, midrotators, or strong rotators. Animals were successively trained on navigation in the Morris water maze (allocentric) and delayed spatial alternation in a water T-maze (egocentric). There were no rotation effects in water maze learning but rotators and nonrotators differed significantly in delayed spatial alternation learning but not relearning. Strong rotators learned more slowly than midrotators, clearly implying that rotational bias and directional learning are not linearly related. We show that it is egocentric spatial learning that is facilitated by a nigrostriatal dopamine asymmetry and extend the generality of the left-right discrimination findings.


Effect of various psychotropic drugs on the performance of avoidance and escape behaviors in rats.

The effect of different doses of nine psychotropic drugs upon conditioned avoidance responses (CARs) developed on a stable basis, after appropriate training, was investigated in rats and compared with their capacity to disrupt escape responses (ERs). Haloperidol (HAL), chlorpromazine (CPZ), morphine (MOR), pentobarbital (PENT), chlordiazepoxide (CDP), meprobamate (MPB), and amphetamine (AMPH) dose dependently inhibited both behaviors. Imipramine also disrupted CARs dose dependently, but did not affect ERs at maximal tolerated doses. Significant differences in the minimal effective doses, effective dose range, and time of onset and duration of action, as well as in potency, were observed. The quantitative determination of the level of selectivity, based upon the ratio ED50 escape failure/ED50 avoidance failure, indicated that all CNS depressants tested caused a selective inhibition of avoidance behavior. HAL was found to be the most specific, followed, in order, by CDP, MOR, CPZ, MPB, and PENT, whose ratio values were not significantly different. AMPH produced a nearly parallel impairment of both behaviors and quipazine only affected CARs at toxic doses. It is concluded that both neuroleptic and nonneuroleptic CNS depressant drugs have selective inhibitory effects on avoidance behavior. Data revealed differences that were more quantitative than qualitative.


Effect of scopolamine and nootropic drugs on rewarded alternation in a T-maze.

The effects of different doses of scopolamine, and of the nootropic drugs oxiracetam and aniracetam, were investigated on the performance of male Wistar rats in a T-maze requiring a spatial discrimination in the stem (reference memory) and an alternate discrimination in the arms (working memory). Criterion (90% correct responses) was reached within 3 days of daily training for stem and 9 days for arm discrimination. Scopolamine (0.1, 0.2, 0.6, and 1.0 mg/kg, SC, 60 min before session) significantly impaired working memory, as shown by a decrease in the number of correct alternations, without affecting reference memory. Both nootropic drugs (25-50 and 100 mg/kg PO) 30 min before scopolamine) attenuated the working memory impairment induced by scopolamine.


Differential effects of octreotide on motor responses to nicotine in rats.

We tested the hypothesis that brain somatostatin levels modify two motor behaviors evoked by ICV infusions of nicotine. Unrestrained, awake rats were given fixed-concentration infusions of nicotine until the prostration/immobility (PI) syndrome and convulsions were produced. Infusion duration ranged from 0.9 to 1.2 min for the PI syndrome and 2.5 to 4.9 min for the convulsions. Octreotide, a stable somatostatin analog (4.5 micrograms, ICV), significantly raised the threshold for nicotine convulsions 1.0 and 5.5 h after pretreatment but not at 24 or 48 h. Cysteamine, a somatostatin releaser and depletor (0.35-0.75 mg/rat, ICV), also caused a dose-dependent increase in seizure threshold. Similarities in the response to octreotide and cysteamine suggest that depression of nicotine convulsions by cysteamine may be mediated by release of endogenous somatostatin. Neither octreotide nor cysteamine altered the threshold for the PI syndrome. These results support the view that one motor behavior evoked by nicotine is subject to control by somatostatin whereas another is not.


Aspirin pretreatment reduces ethanol withdrawal severity in a mouse model of binge drinking.

Nonsteroidal antiinflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and indomethacin, which inhibit prostaglandin (PG) synthesis, have a pronounced effect on a broad range of ethanol (EtOH) actions. Given this, it is somewhat surprising that NSAID treatment has not been found to alter major signs of ethanol withdrawal. To date, the only effect found has been indirect, that is, NSAID treatment reduces the efficacy of PG precursor administration in the treatment of ethanol withdrawal via the inhibition of PG formation. However, in those studies reporting negative results NSAID administration was delayed until EtOH withdrawal. Studies demonstrating NSAID-related attenuation of other actions of EtOH have typically employed a pretreatment paradigm in which NSAIDs are administered prior to, not after, ethanol exposure. Thus, it may be that the point in the ethanol exposure/withdrawal episode at which NSAIDs are administered could be crucial in determining their effects of the ethanol withdrawal syndrome. To address this issue, we employed a multiple-exposure "binge drinking" model. On each of 6 treatment days, male BALB/c mice were injected subcutaneously with either acetylsalicylic acid (ASA, 150 mg/kg) or the buffer vehicle, followed 1 h later by either ethanol (4.0 g/kg) or saline (0.9%) by gavage. Ethanol withdrawal severity, as measured by handling-induced convulsions, was determined 2, 4, 6, 8, 10, 12, and 24 h after EtOH gavage. ASA pretreatment was found to significantly reduce handling-induced convulsions in ethanol-intubated animals. In fact, the attenuation was of such a magnitude that the ASA-pretreated ethanol group did not significantly differ in withdrawal severity from non-ethanol-exposed controls. This effect was not likely due to ASA-related alterations in ethanol pharmacokinetics. These findings have relevance for the understanding of the basic mechanisms underlying ethanol dependence, as well as the potential role of PGs in this phenomenon.


Inhibition of human low-density lipoprotein oxidation in vitro by Maharishi Ayur-Veda herbal mixtures.

In this study, we examined the effect of the Maharishi Ayur-Veda herbal mixtures (MAHMs) Maharishi Amrit Kalash-4 and -5 (M-4 and M-5), MA-631, and Maharishi Coffee Substitute (MCS) on low-density lipoprotein (LDL) oxidation and compared the potency of these mixtures to ascorbic acid, alpha-tocopherol, and probucol. LDL was incubated in 95% air and 5% CO2, with or without 3 microM Cu(+2), in the presence or absence of MAHMs, for 6 or 24 h. In a separate experiment, LDL was incubated as above except MAHMs were added at 0, 1.5, and 3.5 h after incubation started to assess their effect on initiation and propagation of LDL oxidation. Our results demonstrate that MAHMs caused concentration-dependent inhibition of LDL oxidation as assessed by thiobarbituric acid-reactive substances and electrophoretic mobility. The MAHM showed more antioxidant potency in preventing LDL oxidation than ascorbic acid, alpha-tocopherol, or probucol. Also, MAHMs inhibited both initiation and propagation of cupric ion-catalyzed LDL oxidation. These results suggest the importance of further research on these herbal mixtures in the investigation of atherosclerosis and free radical-induced injury.


Naloxone reduces social locomotor activity in rats.

Naloxone, a nonspecific opioid antagonist, has been found to decrease the activity and social behavior of rats tested in pairs but the effects on individual locomotor activity have been equivocal. In the present study, groups of male Long-Evans hooded rats received naloxone (1 or 4 mg/kg, IP) or vehicle alone (isotonic saline) 30 min prior to testing sessions. Individual locomotor activity was measured in two activity boxes (41-cm3) equipped with two infrared photobeams using daily 30-min testing sessions for 5 consecutive days. Following a 1-week washout period (no testing), activity and social attraction (paired distance and contact) were examined in pairs of rats from each group using daily 15-min testing sessions for 4 consecutive days. Locomotor activity and its habituation were not significantly affected by naloxone in rats tested individually. However, both doses of naloxone significantly reduced paired locomotor activity compared to the control group. Measures of social attraction were not significantly affected by naloxone. The present findings suggest that naloxone does not produce nonspecific depressant effects on activity but rather may antagonize opioid release in situational contexts of high arousal (e.g., social activity) with consequent reduction of activity.


Chlordiazepoxide reduces the generalised anxiety, but not the direct responses, of rats exposed to cat odor.

Rats were treated for 5 days with vehicle or chlordiazepoxide (CDP, 5, 10, or 20 mg/kg/day) and then exposed to a cloth impregnated with a neutral or cat odor. Those exposed to cat odor made significantly fewer contacts with the cloth and spent less time in contact with it and more time sheltering than those exposed to the neutral odor. CDP (5 mg/kg) significantly increased the time in contact with both odor cloths, but there were no other significant effects in the cat odor group. Rats previously exposed to cat odor showed significant anxiogenic responses in the social interaction and elevated plus-maze tests that were significantly reversed by CDP. There was no reduction in the responses to the cat odor on a second occasion as a result of the first exposure occurring after treatment with CDP (5 or 20 mg/kg). The anxiogenic effects of pentylenetetrazole (20 mg/kg) as detected in the social interaction and plus-maze tests were unaffected by prior odor experience. It is suggested that during exposure to the cat odor the responses of rats reflect avoidance components of a phobic anxiety state. Benzodiazepines are relatively ineffective against these responses in contrast to their efficacy against the generalised anxiety responses detected in the social interaction and plus-maze tests.


Hippocampal modulation of acoustic startle and prepulse inhibition in the rat.

Prepulse inhibition (PPI) is the normal reduction in a startle response that occurs when the startling stimulus is preceded by a weak lead stimulus ("prepulse"). Schizophrenic patients exhibit abnormally low levels of PPI; therefore, animal models of deficient PPI may provide information regarding neural dysfunctions underlying schizophrenia. We recently reported that infusion of the cholinergic agonist carbachol into the dentate gyrus (DG) disrupts PPI in the rat. We now report the effects of carbachol microinjected into CA1, the DG, or the ventral subiculum (VS) on acoustic startle and PPI. Carbachol infusion into CA1 or the DG depressed startle. Carbachol infusion decreased PPI with a regional rank-order potency CA1 > DG > VS. CA1 infusions more potently depressed the startle reflex. By contrast, DG infusions preferentially decreased PPI, while VS infusions decreased PPI without altering startle amplitude. Coinfusion with the muscarinic cholinergic antagonist atropine opposed the effects of carbachol. These results demonstrate the regional heterogeneity and pharmacological specificity of the hippocampal cholinergic modulation of acoustic startle and PPI and suggest that abnormalities within various regions of the hippocampal formation may contribute to deficient sensorimotor gating in schizophrenic patients.


Stimulus effects of ibogaine in rats trained with yohimbine, DOM, or LSD.

The stimulus effects of ibogaine were compared with those of yohimbine, an alpha 2-adrenoceptor antagonist, 2,5-dimethoxy-4-methylamphetamine (DOM), a 5-hydroxytryptamine2 (5-HT2) agonist, and lysergic acid diethylamide (LSD), a nonspecific 5-HT agonist. Rats were trained with either yohimbine (6 mg/kg), DOM (0.6 mg/kg), or LSD (0.1 mg/kg) vs. no treatment in a two-lever discrimination task. Tests of generalization were then conducted with ibogaine. In yohimbine-trained animals, 39.7% of responses following ibogaine (15 mg/kg) were on the drug-appropriate lever, but this response level was not significantly different from no treatment-appropriate responding. A response distribution that was significantly different from responding under both drug and no treatment training conditions was observed in DOM-trained rats after administration of 15 mg/kg ibogaine. Pizotyline (BC-105) blocked all DOM-appropriate responding produced by ibogaine. In LSD-trained animals, 20 mg/kg ibogaine mimicked LSD. Pizotyline blocked LSD-appropriate responding produced by ibogaine in five of six animals. The present data suggest the involvement of 5-HT2 receptor activity, and the possibility of a 5-HT1A contribution, in the stimulus properties of ibogaine.


Biphasic effects of ethanol tested with drug discrimination in HAD and LAD rats.

Seventh-generation selectively bred high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rats were trained to make differential responses for ethanol (0.75 g/kg, IP) and saline vehicle, following postadministration intervals (PI) of 2 min (HAD-2 and LAD-2 animals) and 30 min (HAD-30 and LAD-30 animals). ED50 values of 0.395 and 0.352 g/kg, respectively, for HAD-2 and LAD-2 animals and 0.269 and 0.314 g/kg, respectively, for HAD-30 and LAD-30 animals reflect the absence of any phenotypic difference for the discriminative stimulus effects of ethanol. HAD-2 animals were more responsive than LAD-2 animals to the stimulating effects of ethanol as measured by total response rates during training sessions. The differential ethanol response generalized to pentobarbital in all four groups but not to morphine, an alternative CNS depressant. The specific antagonist of 5-hydroxytryptamine3 receptors, 3-tropanyl-3,5-dichlorobenzoate (MDL 72222), up to doses of 14.0 mg/kg failed to antagonize the discriminative effects of ethanol. Ethanol sleep times did not differ between groups.


2-Deoxy-D-glucose antinociception and serotonin receptor subtype antagonists: test-specific effects in rats.

The antinociceptive actions of 2-deoxy-D-glucose (2-DG) are mediated in part by endogenous opioid, dopaminergic, cholinergic, histaminergic, and neurohormonal influences. Although 2-DG antinociception was not affected by tryptophan hydroxylase inhibition, a possible serotonergic role in 2-DG antinociception was investigated because of the existence of serotonin [5-hydroxytryptamine (5-HT)] receptor subtypes. The present study examined the effects of general (methysergide: 5 and 10 mg/kg), 5-HT2 (ritanserin: 2.5 mg/kg), and 5-HT3 (ICS-205,930: 0.25-5 mg/kg) receptor subtype antagonists upon 2-DG antinociception on the tail-flick and jump tests in rats. On the tail-flick test, 2-DG (450 mg/kg) antinociception was significantly reduced by all ICS-205,930 doses (48-58%) but unaffected by either methysergide (22-29% reduction) or ritanserin (6% reduction). In contrast, 2-DG antinociception on the jump test was significantly potentiated across the 120-min time course and across the 2-DG dose-response curve (100-650 mg/kg) by methysergide, ritanserin, and ICS-205,930 pretreatment. Each of the three antagonists produced significant leftward shifts in the peak and total 2-DG dose-response curve for the jump test. These data suggest different sites of action for 2-DG antinociception as a function of the pain test employed and a differential modulation by serotonin receptor subtypes at those sites.


Serotonin depletion causes long-term reduction of exploration in the rat.

This study assessed the effects of central serotonergic depletion on exploratory activity at baseline, as well as after administration of d-amphetamine or the anxiogenic beta-carboline FG-7142. Intraventricular 5,7-dihydroxytryptamine (5,7-DHT) induced an almost complete depletion of serotonin [5-hydroxytryptamine (5-HT)] in the medial prefrontal cortex, nucleus accumbens, medial corpus striatum, and hippocampus with no changes in norepinephrine, dopamine or dihydroxyphenylacetic acid concentrations. 5-HT-depleted rats demonstrated reduced spontaneous and d-amphetamine-augmented exploration 3-10 weeks postoperatively. An effect on FG-7142-induced inhibition of exploratory activity was not apparent. These data implicate 5-HT systems in the expression of different aspects of exploratory and amphetamine-augmented motor behaviors.


Calcium changes in rabbit CSF during endotoxin, IL-1 beta, and PGE2 fever.

New Zealand rabbits were chronically incannulated in the lateral ventricle and cisterna magna to assess the hypothesis that calcium concentration (Ca) of cerebrospinal fluid (CSF) varies during fevers of diverse origin. In normothermic and febrile animals recovering from surgery, CSF Ca was positively and significantly correlated to rectal temperature (TR). IV injection of E. coli endotoxin and ICV injection of human recombinant interleukin 1 beta (hrIL-1 beta) induced a TR rise of 1.7 +/- 0.3 degrees C (mean +/- SEM) and 1.45 +/- 0.25 degrees C, respectively, accompanied by significant increases in CSF Ca. After endotoxin administration, maximal Ca increases ranged between 0.21 and 0.48 mM above basal values in individual animals (p < 0.01), whereas after administration of hrIL-1 beta increases were 0.17 and 0.25 mM (p < 0.05). Acetylsalicylic acid (ASA) countered the fever induced by both endotoxin and hrIL-1 beta administrations and concomitantly antagonized the Ca increase in CSF. HrIL-1 beta-derived nonapeptide was characteristically devoid of pyrogenic effect and did not modify CSF Ca. Although ICV injection of prostaglandin E2 (PGE2) increased TR by 2.1 +/- 0.77 degrees C, it failed to have any effect on CSF Ca. Differently from the other Ca enhancers, PGE2, however, increased CSF protein concentration (protein). These findings suggest that brain calcium metabolism plays a role in fever development and that prostaglandin involvement is only engaged once changes in CSF calcium concentration have taken place.


The NMDA receptor antagonist MK-801 has a dissociative effect on seizure activity of hippocampal-kindled cats.

This study assessed the behavioral and electrographic effects of (+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclohepten-5,10-imine maleate (MK-801) (0.1 and 0.5 mg/kg, IP), a noncompetitive antagonist of the NMDA receptors, in hippocampal (HIP)-kindled cats. MK-801 at a higher dose significantly reduced the afterdischarge duration, but not the behavioral seizure stage, of HIP-kindled seizures. This anticonvulsant effect occurred in association with the appearance of severe behavioral toxicity and paradoxical worsening of background electroencephalogram characterized by profound spike and wave discharges. The present data suggest the dissociative effect of MK-801 on seizure activity and limitations of its clinical utility as an antiepileptic agent.


Serotonin receptor ontogeny: effects of agonists in 1-day-old rats.

Although numerous subtypes of serotonin [5-hydroxytryptamine (5-HT)] receptors have been identified in the newborn rat by radioligand binding studies, there have been few studies of the functional significance of these early receptors, most without the benefit of selective drugs. We performed acute dose-response and time course behavioral studies in 1-day-old rats with the putative selective agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (5-HT1A), 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)1H-indole (RU 24969) (5-HT1B), and (+-)1-(2,5-dimethoxy-4-iodo-phenyl aminopropane)-2 (DOI) (5-HT2/1C). The agonists induced distinctive behavioral syndromes. The DOI syndrome mainly included rudiments of forepaw myoclonus and dystonic limb postures, but no shaking behavior (head shakes or wet-dog shakes) or spinal myoclonus, two key reference behaviors for its effects in adult rats. The most distinctive feature of the 8-OH-DPAT-induced syndrome was flat body posture. RU 24969 most significantly increased locomotor activity, inducing propulsive movements with episodic rests and sudden hindlimb jerks. These studies suggest that functional and differential activity of 5-HT1A, 5-HT1B, and 5-HT2/1C receptors occurs much earlier in the rat than previously appreciated. The absence of DOI-induced shaking behavior and spinal myoclonus, however, suggests incomplete maturation at the level of the receptor or effector pathways for these behaviors.


Effects of diurnal phase and pimozide on cholecystokinin-elicited hypoactivity in the hamster.

Locomotor activity in golden Syrian hamsters was measured following IP injections of cholecystokinin (CCK; 25 micrograms/kg) and pimozide (0.5 mg/kg), the dopamine receptor antagonist. In addition, animals were tested during either the dark or light phase of the diurnal cycle in either dark or light running wheel environments. Results indicated that CCK-elicited hypoactivity was blocked by pimozide and that the effect of CCK was evident only among animals tested during the light phase of the daily cycle. Ambient lighting conditions in the test environment did not modify the drug effects. Independently of any drug effect, locomotor activity was affected by diurnal phase and ambient lighting in the test environment. Animals were more active when tested during the dark phase than during the light phase and locomotor activity was higher under dark than under light ambient conditions. It is concluded that diurnal phase modulates CCK's effect on hamster locomotion and that CCK's effect on locomotion is mediated, in part, by dopaminergic mechanisms.


Activity of tryptophan hydroxylase in brain of hereditary predisposed to catalepsy rats.

The activity of the rate-limiting enzyme of serotonin biosynthesis, tryptophan hydroxylase (TPH), was studied in the brain of rats bred for 20 generations for predisposition to catalepsy (an excessive freezing). Increased TPH activity was found in the striatum but not in the hippocampus and midbrain of cataleptic rats compared with Wistar ones. Km for the enzyme from the striatum of cataleptics was twice as low as that in control rats, although no difference in their Vmax was found. The increase in TPH activity in the striatum of cataleptics was nonadditive with its activation induced by incubation in vitro of the enzyme under phosphorylating conditions and could be completely reversed with alkaline phosphatase. An administration of p-chlorophenylalanine, an irreversible inhibitor of TPH, decreased the duration of freezing in cataleptic rats. These findings indicate that hereditary predisposition to catalepsy is associated with increased TPH activity in the striatum due to local phosphorylation of the enzyme and suggest an essential role of the activation of striatal TPH in genetic predisposition to catalepsy.


Thiazolo[3,2-a]pyrimidine derivatives as calcium antagonists.

Some new thiazolo[3,2-a]pyrimidine derivatives were prepared refluxing 2-thioxo-1,2,3,4-tetrahydropyrimidine derivatives with phenacyl bromide in glacial acetic acid. Calcium antagonistic activities of these compounds were evaluated in K(+)-depolarized rat aorta, using nifedipine as reference compound.


[Mucus models for investigation of intestinal absorption mechanisms. 3. A mathematical simulation model of drug diffusion through enteral mucus].

The diffusion of drug substance in a closed three-compartment model through a mucus layer to equilibrium is simulated by available pharmacokinetic programs. The obtained curves conform very well to the values experimentally found. If mucus is replaced by buffer solution an explicit equation from the literature, the method used and the experimental findings give the same results. Examination of the rate constants k1 for the diffusion in, kD through and k2 from the mucus shows the significance of the relation k1/k2 > 1, = 1, < 1 as a measure for the affinity of the active agent to the mucus. The discussion of the kinetic parameters shows, as in previous results, no criterion for assuming specific mucus binding. Because of its unspecifity the usual term "mucus binding" should be replaced by "mucus retention".


Effect of calcium on dark adaptation in Phycomyces phototropism.

Adaptation processes enable phototropism of Phycomyces to operate over a 10-decade range of blue-light intensity (1 nW m-2-10 W m-2). To investigate the influence of calcium on dark adaptation, the phototropic latency method was employed with the modification that sporangiophores were temporarily immersed in solutions containing CaCl2 or LaCl3. Following such treatment, the time course of bending was found to have two components with distinct latencies and bending rates. After immersion in darkness for 30 min in LaCl3 solution or 1 h in a solution of CaCl2, MgCl2, or the calcium chelator EGTA, each sporangiophore was adapted to a blue light beam (1 W m-2) for 45 min by rotation around its vertical axis. Cessation of rotation defined the onset of the phototropic stimulus, at which time the intensity was reduced by as much as 10(3)-fold. For a 10(2)-fold reduction (to 10(-2) W m-2), immersion in CaCl2 (10-100 microM) reduces the latency 13 min for the early bending component and 18 min for the late component, whereas treatment with the calcium-channel blocker lanthanum (0.1-11 microM LaCl3) increases the latency 12 min for the early component and 13 min for the late component. EGTA (10 microM) also had an inhibitory effect, increasing the latency of the first and the second components by 7 and 10 min, respectively. In experiments performed similarly, but without the light adaptation treatment after immersion, no differences between calcium-treated and control sporangiophores were found. The bending rates of both components show only a weak dependence on calcium.(ABSTRACT TRUNCATED AT 250 WORDS)


The distance between the phytochrome chromophore and the N-terminal chain decreases during phototransformation. A novel fluorescence energy transfer method using labeled antibody fragments.

A novel antibody-fluorescence method has been developed to elucidate the chromophore topography in phytochrome as it undergoes a photochromic transformation. Förster energy transfer from N-terminal bound, fluorescently labeled Oat-25 Fab antibody fragments to the phytochrome chromophore was measured. The results suggest that the chromophore moves relative to the N-terminus upon the Pr-->Pfr phototransformation. This conclusion is consistent with previous models which have proposed a reorientation and an interaction of the Pfr chromophore with the N-terminus. The method described appears to be the first study of a Förster energy transfer measurement using a donor-label attached to a Fab fragment of a photosensor protein.


Phytochrome evolution: a phylogenetic tree with the first complete sequence of phytochrome from a cryptogamic plant (Selaginella martensii spring).

We have sequenced cDNA and genomic clones coding for phytochrome of the fern Selaginella. On the amino acid level, this phytochrome shares sequence homologies with phytochromes of higher plants which range between 62 (phytochrome B of Arabidopsis) and 55 (56)% [phytochrome C of Arabidopsis (Avena)]. Introns in the Selaginella gene are short and occupy positions known from phytochrome sequences of higher plants. A rooted phylogenetic tree based on mutation distances puts Selaginella phytochrome closest to the hypothetical ancestor. A similar tree arises if the tree is constructed with partial sequences (about 200 amino acids) around the chromophore attachment site. An extension of this tree by sequences of other cryptogamic plants (Mougeotia, Ceratodon, Psilotum) shows all these sequences including those of the phytochromes B and C of Arabidopsis on a branch, well separated from the branch formed by phytochromes known to accumulate in etiolated plants. The rooted phytochrome phylogenetic tree, however, is difficult to reconcile with the fossil record.


Detection and partial sequence of phytochrome genes in the ferns Anemia phyllitidis (L.)Sw (Schizaeaceae) and Dryopteris filix-mas L. (Polypodiaceae) by using polymerase-chain reaction technology.

Phytochrome controls several developmental steps during formation and differentiation of the fern gametophyte, including spore germination, morphogenesis of the gametophyte or differentiation of the sexual cells. To obtain information about the amino acid sequence and the regulation of phytochrome expression at the gene level, two degenerated oligonucleotides against well conserved amino acid regions were designed after an optimal alignment of the known phytochrome sequences. These primers were tested against DNA isolated from Arabidopsis thaliana, and the polymerase-chain reaction (PCR) products were cloned and sequenced. The DNA fragment produced with this method proved to be identical with a phytochrome-A-gene fragment from A. thaliana, and hence this fragment was used in further experiments to prove whether amplified DNA from fern species contains phytochrome-like DNA. With this procedure we successfully detected and cloned gene fragments both from gametophytes of Anemia phyllitidis and Dryopteris filix-mas, cultured for 7 days under vegetative conditions. In addition, poly(A)+ RNA was prepared from 7-day-old gametophytes of A. phyllitidis, induced to differentiate antheridia under generative conditions. This poly(A)+ RNA was transcribed into complementary DNA and used together with both phytochrome specific primers in a PCR experiment. We thereby obtained another DNA fragment. These data strongly suggest that A. phyllitidis has at least two phytochrome genes, and that at least one of them is expressed in light-grown gametophytes.


Partial nucleotide sequence of phytochrome from the zygnematophycean green alga Mougeotia.

Following polymerase chain reaction, a fragment of about 800 bp was amplified from genomic Mougeotia DNA using oligonucleotides directed to conserved regions of known phytochrome genes. The nucleotide sequence points to a different exon/intron structure in the neighborhood of the chromophore attachment site of this Mougeotia phytochrome gene, as compared to other phytochromes. Alignment of the derived amino acid sequence to phytochromes of higher and lower plants shows highest homology (> 60%) to type II (green type) phytochrome, while Northern blot analysis of total Mougeotia RNA indicates down-regulation of the phytochrome transcription in light. Signal pattern of hybridized genomic DNA after digestion reveals the presence of probably only one phytochrome gene in Mougeotia.


Expression of oat phyA cDNA in the moss Ceratodon purpureus.

The possibility of transforming Ceratodon purpureus protoplasts by PEG-mediated direct DNA uptake was tested. Transformation with a plasmid carrying a kanamycin-resistance gene resulted in kanamycin-resistant colonies of C. purpureus protonemata. A full-length cDNA clone coding for oat phyA phytochrome was isolated. The clone HM4.1 which is 3.7-kb long exhibits about 99% nucleotide sequence identity to the known phytochrome clone AP3. The expression of HM4.1 in C. purpureus protonemata was tested. A construct with the 35S-promotor and the structural gene of HM4.1 was cotransformed with the plasmid containing the kanamycin-resistance. Kanamycin-resistant colonies were tested for the presence of HM4.1 sequences in a genomic Southern experiment. Two out of 19 kanamycin-resistant colonies reacted positively with a HM4.1 specific probe. The expression of phyA in the positive colonies was examined with monoclonal antibodies specific for oat phytochrome. The Western blot experiment with protein extracts of the two positive colonies grown in the dark revealed clear signals at 124-kDa which were not detected in control plants. These data demonstrate the possibility of expressing oat phyA-apoprotein in C. purpureus protonemata. The transgenic moss protonemata did not show phenotypical alterations in response to the foreign phytochrome polypeptide; it is not known at the moment if the tetrapyrole chromophore is attached to the oat polypeptide in the protonemata or not.


Events in the phytochrome molecule after irradiation.

The photoconversion of Pr to Pfr has been investigated by a large number of investigators. We have previously demonstrated that Z, E isomerization of the tetrapyrrole chromophore is involved in the photoconversion. It is the best candidate for the primary photoreaction. Conformation and configuration of the Pr chromophore will be compared with that of chromophores in phycocyanin. The crystal structure of phycocyanin had been elucidated by x-ray analysis. Proton transfer and/or Z, E isomerization of the tetrapyrrole are probably involved in different steps of the photoconversion in phytochrome and in photoreversible phycobiliproteins. Fluorescence decay kinetics of irradiated Pr and intermediate formation show heterogeneity. Possible reasons for this heterogeneity will be discussed.


Calcium-regulated nuclear enzymes: potential mediators of phytochrome-induced changes in nuclear metabolism?

Calcium ions have been proposed to serve as important regulatory elements in stimulus-response coupling for phytochrome responses. An important test of this hypothesis will be to identify specific targets of calcium action that are required for some growth or development process induced by the photoactivated form of phytochrome (Pfr). Initial studies have revealed that there are at least two enzymes in pea nuclei that are stimulated by Pfr in a Ca(2+)-dependent fashion, a calmodulin-regulated nucleoside triphosphatase and a calmodulin-independent but Ca(2+)-dependent protein kinase. The nucleoside triphosphatase appears to be associated with the nuclear envelope, while the protein kinase co-purifies with a nuclear fraction highly enriched for chromatin. This short review summarizes the latest findings on these enzymes and relates them to what is known about Pfr-regulated nuclear metabolism.


Signal transduction by phytochrome: phytochromes have a module related to the transmitter modules of bacterial sensor proteins.

A C-terminal section of phytochromes turned out to share sequence homologies with the full length of the transmitter modules (about 250 amino acids) of bacterial sensor proteins. Coinciding hydrophobic clusters within the homologous domains imply that the overall folding of the two different types of peptides is similar. Hence, phytochromes appear to possess the structural prerequisites to transmit signals in a way bacterial sensor proteins do. The bacterial sensor proteins are known to be environmental stimuli-regulated kinases belonging to two-component systems. After sensing a stimulus by the N-terminal part of the sensor protein, conformational alterations confer the signal to its (mostly) C-terminal transmitter module which in turn is transitionally autophosphorylated at a conserved histidine. From the histidine the phosphate is transferred to the receiver module of a system-specific regulator protein which eventually acts on transcription or enzyme activity. The histidine is not conserved in phytochromes. Instead, a conserved tyrosine is found spatially very close to the histidine position. This tyrosine might play the role of histidine, and kinase function might be associated with this part of phytochrome. In spite of this divergence, the structural similarities point to a common evolutionary origin of the phytochrome and bacterial modules.


Effective courtroom testimony.

Participating in a medical/legal situation is quite different from the ordinary office or hospital experience and requires the expert to see that all of the new parameters are clarified. A thorough and complete evaluation with a review of all the pertinent records and interviews with ancillary individuals is necessary, as is good preparation by way of a pre-trial conference with the attorney. Review of all notes and records prior to deposition or testimony can put the expert at ease. Once under oath, the expert is expected to tell the truth and not advocate for the retaining party. On the other hand, the expert must advocate for his opinion. When the answer is not known, or when one is proven wrong because new data is presented, then the expert must readily admit this. The expert should take the necessary time, pausing, listening to the question, reflecting upon the answer, giving time to the attorney to object. This trip through the vagaries of the legal system should assist psychiatrists in feeling more at ease when participating in forensic matters.


Systems ethics and the history of medical ethics.

This paper reviews the current conclusions in medical ethics which have followed the 1969-1970 Medical Ethics Discontinuity, a break that challenged the Hippocratic way of thinking about ethics. The resulting dislocations in quality of care and the medical value system are discussed, and an alternative medical ethics is offered: Systems Ethics. A methodology for a Systems Ethics analysis of cases is presented and illustrated by the case of a physician-assisted suicide. The advantages, both theoretical and clinical, of a Systems Ethics approach to medicine, which is an expansion of the Hippocratic tradition in medical ethics, are developed. Using Systems Ethics, it is possible to avoid the dangers of legalism, bureaucratic ethics, utilitarian cost cutting, and "political correctness" in medical ethics.


Tailoring adult psychiatric practices to the field of geriatrics.

The United States' population is aging. Epidemiological surveys suggest significant rates of mental illness amongst the rapidly growing over-65 cohort. A burgeoning experience and data base related to the developing sub-discipline of geriatric psychiatry is now available. This article synthesizes key issues and concepts as an introduction to geropsychiatric practice-in particular, a) the interface between medical illness and psychiatric expression in the elderly, b) delirium, c) dementia, and d) depression-and considers their interactions. Finally, there is a brief overview of geriatric psychopharmacology, followed by clinically-oriented discussions of each of the major classes of psychotropics as applied to a geriatric population.


Diagnosis and treatment of personality disorders.

This article touches on four current areas of controversy in the field of the personality disorders -- definition, etiology, assessment, and treatment. There is a tremendous amount of disability, personal distress, and public health expense as a result of the personality disorders. We are seeing steady progress in each of these areas. The implications of this progress are enormous, and the interest in this area is widespread, not just among psychiatric health professionals or among patients and their families and friends, but also among the public at large.


A district survey of paediatric outpatient referrals.

A prospective analysis of general paediatric outpatient referrals to a district general hospital was conducted over four months. Because of geographical characteristics, this probably represents all referrals within the district during that time. The referral rate referral rate was 15.5 per thousand per annum. Only five children did not see a consultant at their first visit. One hundred and five children were discharged after one consultation. Communication between general practitioners and hospital appeared generally good. Although only 56 referral letters stated the urgency of referral, 351 (94%) stated a reason for referral. One hundred and five children could have been dealt with by the community child health service. The NHS reforms, fund-holding practices and the development of the community child health service may profoundly affect current outpatient workloads and practice.


Limitations of the OPCS congenital malformation notification system illustrated by examination of congenital malformations of the cardiovascular system in districts within the Trent Region.

Data are presented from OPCS notification statistics and other sources on rates of congenital cardiovascular malformations in the Trent Health Region and in its constituent Districts. While Trent in general, and some of its districts in particular, show high notification rates, other data sources suggest that the underlying malformation rate may not be raised compared with that seen nationally. Reasons for this discrepancy are discussed and the OPCS notification system is compared with that in Scotland.


Transferable deaths during 1990 for residents of Camberwell Health Authority.

Almost one quarter of all deaths among residents of Camberwell District Health Authority during 1990 occurred without the district ('transferable deaths'). These deaths differed from total deaths in that the main cause of study deaths was cancer, and many of these cases died in a hospice with which the district has no direct contact. However, the commonest location of deaths was in hospitals (57% of study death locations) and the majority of these cases died in London teaching hospitals with whom there are major contracts. As the three inner London South East Thames districts, including Camberwell, propose to merge into a single purchasing authority in 1993, all London hospitals where Camberwell residents died in this survey would be covered by the current range of contracts set by the three districts. The study identified a small but important group of deaths from HIV/AIDS, where it seems that people travelled, particularly, to West London for terminal care. A high proportion of deaths from injury and poisoning were either suicides or open verdicts. There were less transferable deaths among the major ethnic minorities in the district than expected, particularly among those of African and Caribbean descent. This may be due to the age and disease patterns in these populations, but may also require study into the need for terminal care among these groups. Transferable deaths are a useful source of epidemiological information and can highlight local health service strengths and deficits.


Awareness and practice of contraception among female students at the Institute of Management and Technology (IMT), Enugu.

A study of the knowledge, attitudes to and practice of contraception among the female students at the Institute of Management and Technology (IMT), Enugu, was carried out, involving 266 female students out of a total female student population of 1,510. The mean age of the population sample was 19.1 years and 254 (95%) were single. Ninety-six percent were aware of the availability of contraceptives. Knowledge relating to the practice of contraception was superficial since as many as 61% of the objectors believed that contraception subsequently led to infertility. One hundred and thirty (49%) of the studied population had used one form of contraception or another sometime in their lives. Seventy-six percent had not used any contraception for initial intercourse. The rhythm method followed by the barrier method were the most popular forms of contraception. Practice of contraception by the studied population was inconsistent as 21% of the students eventually had an unwanted pregnancy and 18% had an induced abortion. Health education is strongly recommended to our women folk in order to reduce the high incidence of unwanted pregnancy and its associated medical and social complications.


Beliefs about prematurely erupted teeth in rural Yoruba communities, Nigeria.

A descriptive study was carried out in two villages: Badeku and Olodo, near the city of Ibadan, between May and November 1990. The objective of the study was to investigate the knowledge, beliefs and attitudes of respondents to premature eruption of deciduous teeth in babies. Of the 622 people interviewed, a large proportion (30.5%) believed that the first deciduous tooth should erupt between the age of 5-7 months; the next commonly mentioned time of tooth eruption was 7-9 months of age; and 50.3% of the respondents claimed to have seen a case of prematurely erupted primary teeth. There was a statistically significant association between age and also between educational status of respondents and having seen premature eruption of teeth (P < 0.01). The majority of the people (53.7%) felt that the condition was an indication of an evil child. Only 22.1% of those interviewed thought it could be just an individual variation. On the recommended remedy or management of the condition, as many as 26 (4.1%) said they would get rid of the child. A high percentage felt that sacrifices should be offered to appease the gods. It is suggested that a transcultural approach be adopted in managing cases in which the parents feel particularly anxious and uncomfortable about prematurely erupted teeth in order to cater for the social well-being of the child and family. It is also recommended that appropriate health education be directed at the society as a whole concerning this condition.


Acute pesticide poisoning in the UK and information and training needs of general practitioners: recording a conundrum.

A postal questionnaire of all general practitioners (n = 68) in a District Health Authority was undertaken to identify the information and training they had received on acute pesticide poisoning. Fifty-six (82%) replies were received. The responses showed that 33 (59%) had not seen the standard Department of Health Guide to acute pesticide poisoning and only 20 (36%) of the respondents thought that their practice had a copy of this publication. None of those surveyed had ever used Health and Safety Executive Guidance Notes on pesticides. Ten practitioners (18%) reported that they had at some time diagnosed a case of acute pesticide poisoning and three (5%) had done so in the last two years. Only three respondents (5%) considered they had sufficient information to diagnose all the main pesticides listed in the Department of Health Guide but 24 (43%) considered they had sufficient information to diagnose rodenticide poisoning. Twenty-three (41%) considered they had insufficient information to diagnose any acute pesticide poisoning category. The sources of information used in cases of suspected acute pesticide poisoning were the National Poisons Information Services (e.g., Guy's Hospital) for 30 (54%); Accident and Emergency Departments for 19 (34%); and industry for nine (16%). Four (7%) considered they had sufficient training as a medical student to diagnose cases of acute pesticide poisoning and four (7%) considered they had sufficient training since graduating to diagnose such cases. Some of the problems related to the identification and diagnosis of acute pesticide poisoning are discussed and a number of specific recommendations are made to improve the information and training available to general practitioners.(ABSTRACT TRUNCATED AT 250 WORDS)


Diagnostic exposure in a primary care clinic during pediatric training.

A retrospective and descriptive study was done in a general pediatric training site with the purpose of identifying the diagnoses to which the trainees have been exposed, as well as the changes in the pattern of these diagnoses. The number of patient-doctor contacts, type of patient visit, and frequency of diagnoses were compared. A total of 66,054 patient-doctor contacts occurred during the years 1979 to 1989, comprising 79.6 percent scheduled health visits and 20.4 percent emergency visits. The main diagnoses were: healthy child/adolescent (HV), well baby (WB), upper respiratory infection, skin diseases, bronchial asthma, acute gastroenteritis, otitis media, anemia, incomplete immunization, psychosocial problems, nutritional/linear growth problems, psychosomatic disturbances, parasitosis, and pneumonia. There was a significant decrease (P < .005) in the diagnosis of infectious diseases and a significant increase (P < .005) in the proportion of WB and HV. The latter were the two most common diagnoses in the year 1989.