Risk of cardiac events in atypical transient ischaemic attack or minor stroke. The Dutch TIA Study Group.

Proposed guidelines for the diagnosis of transient ischaemic attack (TIA) involve interpretation of symptoms, so it can be very difficult to distinguish a TIA from other disorders, such as migraine, epilepsy, syncope, or neurosis. Atypical cerebral and visual events may be classified as TIA. To see whether TIA or stroke patients with atypical cerebral or visual symptoms are at high or low risk of cardiac complications, we prospectively followed 572 patients (entered into the Dutch multicentre TIA trial) with a diagnosis of TIA or minor ischaemic stroke, but whose symptoms did not fully accord with internationally accepted criteria. We compared their outcome with that of 2555 other TIA or stroke patients in the trial, who had unequivocal symptoms; all patients were treated with aspirin. During mean follow-up of 2.6 years the risk of a major vascular event did not differ between the groups (14.5% in patients with atypical symptoms vs 15.1% of patients with typical attacks). Patients with atypical attacks had a lower risk of stroke (5.6% vs 9.4%, hazard ratio 0.6, 95% confidence interval 0.4-0.9) and a higher risk of a major cardiac event (8.4% vs 5.9%, 1.4, 1.0-2.0) than did patients with typical attacks. These differences could not be explained by differences in cardiac risk factors, and were independent of minor discrepancies in baseline characteristics between the groups. A heavy or tired feeling in one or two limbs was the only atypical symptom associated with cerebral rather than cardiac events (ratio cardiac/cerebral events 0.8). For all other atypical symptoms cardiac events were about twice as common as cerebral events (range 1.3-2.5). Our findings suggest that TIA or minor stroke patients with atypical symptoms may have symptomatic heart disease, especially cardiac arrhythmia.


Efficacy of atovaquone in treatment of toxoplasmosis in patients with AIDS. The NIAID-Clinical Center Intramural AIDS Program.

Atovaquone (formerly 566C80) is a hydroxynaphthoquinone with potent activity against Toxoplasma in vitro and in laboratory animals. Eight patients with AIDS and presumed or biopsy confirmed toxoplasmosis who were intolerant of or had not responded to standard therapies were treated with oral atovaquone 750 mg four times a day. Seven patients showed radiographic improvement; the other remained radiographically stable. Six patients died 6-60 weeks after enrollment with no clinical (six) or necropsy (three) evidence of recurrent toxoplasmosis; two patients relapsed at 10 and 32 weeks. Toxicity was mild: only one patient required temporary discontinuation of drug due to a rash. Atovaquone is a well-tolerated drug that appears to be an effective alternative for patients with toxoplasmosis who are intolerant of standard therapies.


Efficacy and toxicity of eflornithine for treatment of Trypanosoma brucei gambiense sleeping sickness.

The usual first-line treatment for Trypanosoma brucei gambiense sleeping sickness is melarsoprol, but when that fails the outlook has hitherto been grim. The polyamine synthesis inhibitor eflornithine (difluoromethylornithine, DFMO) has emerged as an alternative therapy. 207 patients with late-stage T b gambiense sleeping sickness were treated in rural Zaire with three different regimens of DFMO in an open-trial design. During treatment, trypanosomes disappeared from the CSF of all 87 patients in whom parasites had been seen before DFMO administration, and there was a sharp fall in CSF white cell count from a mean of 186/microliters to 21/microliters. 152 patients have been followed for at least a year after DFMO treatment, and only 13 (9%) have relapsed. Treatment failures were more common in children less than 12 years, among patients treated with oral DFMO only, and among patients who received DFMO as the initial treatment of their recently diagnosed trypanosomiasis. Toxicity was acceptable. Only 4 patients died during or shortly after treatment. Bone marrow suppression resulting in anaemia (43%) or leucopenia (53%) was common but bore little consequence. This open trial shows that DFMO is as active as and possibly less toxic than melarsoprol. For economic and logistic reasons DFMO may not be the first-choice therapy in rural Africa but for the vast majority of patients who relapse after melarsoprol DFMO will be curative.


The electrophysiological actions of dopamine and dopaminergic drugs on neurons of the substantia nigra pars compacta and ventral tegmental area.

The dopaminergic neurons of the substantia nigra pars compacta and ventral tegmental area play a crucial role in regulating movement and cognition respectively. Several lines of evidence suggest that a degeneration of dopaminergic cells in the substantia nigra produces the symptoms of Parkinson's disease. On the other hand, a hyperactivity of the dopaminergic transmission in the brain induces dyskinesia, dystonia and psychosis. It is also well established that the euphoric and rewarding responses evoked by drugs of addiction, such as amphetamine and cocaine, are mediated by central dopamine systems. Electrophysiological experiments which study the activity of single dopaminergic neurons in the ventral mesencephalon have shown that dopamine and dopaminergic drugs reduce the firing frequency of these cells. This is due to the stimulation of D2-D3 autoreceptors and to a hyperpolarization of the membrane produced by an increase in potassium conductance. In addition, substances which increase the release (amphetamine), the synthesis (levodopa) or block the uptake (cocaine, nomifensine, amineptine) of dopamine in the brain inhibit the firing activity of the dopaminergic cells throughout dopamine-mediated mechanisms. In this review, we will briefly examine the literature concerning the physiological and behavioural responses caused by dopamine and dopaminergic agents on the dopaminergic neurons of the ventral mesencephalon. Our conclusion suggests that the electrophysiological actions of dopamine and dopamine-related drugs on dopaminergic cells in the ventral mesencephalon might be indicative of the pharmacological effects of these agents on the brain.


Stimulatory effects of quinpirole hydrochloride, D2-dopamine receptor agonist, at low concentrations on prolactin release in female rats in vitro.

Dopamine (DA) has dual actions (inhibitory and stimulatory) in the regulation of prolactin (PRL) release, depending on its concentration. To investigate the stimulatory effects of DA, perifused rat anterior pituitary cells were exposed to the highly-specific DA D2 receptor agonist, quinpirole hydrochloride (LY). Very low concentrations of LY (10(-12)-10(-10) M) stimulated PRL release and potentiated thyrotropin-releasing hormone (TRH)-induced PRL release. Higher concentrations of LY did not stimulate. Pretreatment with pertussis toxin (30 ng/ml, 24 h) completely abolished these effects of LY. The D2 receptor antagonist, metoclopramide, also blocked the potentiation by LY of TRH-induced PRL release. These data indicate that very low concentrations of dopamine stimulate PRL release via an interaction with a D2 receptor connected to a pertussis toxin-sensitive G protein.


Amyl nitrite related deaths.

Two cases of death associated with amyl nitrite are discussed. An attempt is made to highlight its noxious properties and the difficulty in attributing death to it when inhaled.


Possible cell-free prion replication.

Spongiform encephalopathies, such as scrapie or bovine spongiform encephalopathy in animals, or kuru, Creutzfeld-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker disease (GSS) in man, seem to be caused by a transmissible agent whose nature is still a matter of debate. The properties of this agent which has been designated as prion, differ from those of any other known infectious agents, including viruses and viroids. Several lines of evidence suggest that the prion is devoid of nucleic acid and is identical with a modified form of a normal host protein. This lack of nucleic acid poses the question of how a protein moiety can propagate itself as a transmissible agent. Here it is proposed that prion replication is a process similar to crystallization and as such, the propagation of prions can take place as a sort of chain-reaction in an in vitro cell-free system.


N-methyl-D-aspartate exposure blocks glutamate toxicity in cultured cerebellar granule cells.

Exposure of cultured cerebellar granule cells to glutamate results in a concentration-dependent (EC50 = 22.7 +/- 0.4 microM) and delayed (24-72 hr) neurotoxicity, which is blocked by the specific N-methyl-D-aspartate (NMDA) receptor antagonists 2-amino-5-phosphovalerate and MK-801 but is unaffected by the non-NMDA receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione and 6,7-dinitroquinoxaline-2,3-dione. Although glutamate toxicity in these cells is mediated by the NMDA subtype of glutamate receptor, pretreatment of cerebellar granule cells with subtoxic concentrations of NMDA markedly antagonizes the neurotoxic actions of glutamate, with an IC50 of 55 +/- 4 microM. The neuroprotective effect of NMDA requires a preincubation time of approximately 120 min to be fully manifested and does not require the presence of NMDA during glutamate exposure. These data demonstrate that NMDA receptors mediate both neurotoxicity and neuroprotection in cerebellar granule cells. Among four glutamate receptor agonists tested (NMDA, quisqualate, ibotenate, and kainate), only NMDA was able to provide a robust neuroprotection against glutamate toxicity. Quisqualate was neither neurotoxic nor neuroprotective, whereas ibotenate, which was nontoxic by itself, induced a small degree of neuroprotection. In contrast, kainate, which was neurotoxic to cerebellar granule cells, also provided considerable neuroprotection against glutamate toxicity. Because preincubation of cerebellar granule cells with NMDA fails to alter NMDA receptor-mediated phosphoinositide hydrolysis or the specific binding of [3H]MK-801 to NMDA receptors, it appears that the neuroprotective effects of NMDA are not due to NMDA receptor desensitization.


A naturally occurring tyrosine to histidine replacement at residue 33 of human thymidylate synthase confers resistance to 5-fluoro-2'-deoxyuridine in mammalian and bacterial cells.

Structural changes in the macromolecular targets of pharmacological agents can result in alterations in the efficacy of these agents. In previous studies, we identified a variant structural form of thymidylate synthase (TS) that is associated with relative resistance to 5-fluoro-2'-deoxyuridine, in a human colonic tumor cell line. We now report on the use of DNA transfer techniques to examine directly the effects of each TS form on drug response. TS cDNA constructs, corresponding to the normal or variant TS mRNA, were expressed in Chinese hamster lung cells or in Escherichia coli, and response to 5-fluoro-2'-deoxyuridine was determined. We observed that expression of the variant TS, which differs from the normal form by a tyrosine to histidine substitution at residue 33, confers a 4-fold level of drug resistance in the mammalian cells, as well as in bacteria. The possible role of Tyr-33 in 5-fluoropyrimidine-mediated inhibition of TS is discussed.


Characterization of functional interactions of imidazoquinoxaline derivatives with benzodiazepine-gamma-aminobutyric acidA receptors.

U-78875 [imidazo[1,5-a]quinoxalin-4(5H)-one, 3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-5-(1-methylethyl)] belongs to a series of imidazoquinoxaline derivatives, recently discovered ligands with high affinity for benzodiazepine receptors. In this study, we have examined the drug and its analogs for their modes of interaction with the receptors, with a particular emphasis on finding molecular determinants for their functional properties. Changes in the substituents on N5 and C6 of the heterocyclic ring produced no major effects on binding characteristics but yielded drugs of widely varying efficacy (antagonist to full agonist), measured as gamma-aminobutyric acid (GABA)-mediated 36Cl- uptake and t-butylbicyclophosphoro[35S]thionate binding in rat cerebrocortical membranes. The relative binding affinity and efficacy of the analogs measured in brain membranes were similar to those in cloned GABAA receptors of the alpha 1 beta 2 gamma 2 (type I) and alpha 3 beta 2 gamma 2 (type II) subtypes. The imidazoquinoxalines showed no marked subtype selectivity. Their Ki value against [3H]flunitrazepam binding for type I was only 2-3 times lower than that for type II, and their rank order for agonistic activity was the same in the two subtypes, measured as GABA-mediated Cl- currents in human kidney cells (A293) expressing the subtypes of GABAA receptors. According to computational modeling of the drugs using both molecular and quantum mechanics, the agonistic activity of the imidazoquinoxaline derivatives depends on the presence of a bulky alkyl substituent at N5 and the deformation of the substituted portion of the otherwise planar ring system induced by a bulky moiety at N5 or C6. With a fixed N5 substituent (isopropyl), the relative efficacy in the brain membranes, as well as in the cloned receptors, appeared to be dependent on the degree of the ring deformation. This out-of-plane portion of the imidazoquinoxalines can be assigned to the general region occupied by the 5-phenyl group of diazepam and other agonistic functional groups of several nonbenzodiazepine ligands. It seems that this region, apparently common to various agonistic ligands, interacts with an agonistic pocket in type I and type II subtypes of the benzodiazepine receptors in the brain. Our results also provide direct support for the view that the agonists and nonagonists share largely overlapping binding regions in the benzodiazepine receptor, which has been proposed earlier from in vivo efficacy measurements of other series of ligands.


Molecular pharmacological differences in the interaction of serotonin with 5-hydroxytryptamine1C and 5-hydroxytryptamine2 receptors.

5-Hydroxytryptamine (5HT)1C and 5HT2 receptors appear to be closely related, from a molecular viewpoint, displaying similar second messenger systems and a high degree of sequence homology. However, there are striking differences in the interactions of 5HT with 5HT1C and 5HT2 receptors; 5HT is generally more potent in stimulating responses mediated through 5HT1C receptors than responses mediated through 5HT2 receptors. Also [3H]5HT labels 5HT1C receptors and not 5HT2 receptors. In order to explore more fully the molecular rationale for these differences, radioligand binding studies were performed in rat, human, and porcine brain and choroid plexus tissues and in mammalian cells transfected with rat 5HT1C or 5HT2 receptors; second messenger studies (inositol phosphate accumulation) were performed in the transfected cells. The second messenger studies confirmed the approximately 10-fold higher potency of 5HT in stimulating intracellular responses through 5HT1C receptors (EC50 = 8.3 nM) than in stimulating intracellular responses through 5HT2 receptors (EC50 = 101 nM). An agonist radioligand selective for the 5HT1C and 5HT2 receptors, 2,5-dimethoxy-(4-[125I]iodo)phenylisopropylamine, was used, as well as [3H]5HT, [3H]mesulergine (antagonist radioligand for 5HT1C receptors), and [3H]ketanserin (antagonist radioligand for 5HT2 receptors). Computer-assisted analyses of the binding data revealed two agonist affinity states for the 5HT1C receptor. The agonist high affinity state of the receptor was modifiable by guanyl nucleotides. The proportion of agonist high affinity states, relative to the total receptor population, was approximately 10% for both receptors. The apparent higher affinity of 5HT for the radiolabeled 5HT1C receptors was due to the higher affinity 5HT displayed for the agonist low affinity state of the 5HT1C receptor, compared with the affinity of 5HT for the agonist low affinity state of the 5HT2 receptor. The correspondence between the higher affinity of 5HT for the agonist low affinity state of the 5HT1C receptor, relative to the 5HT2 receptor, and the higher potency of 5HT in stimulating 5HT1C responses indicates that 5HT interacts with the agonist low affinity state of the 5HT1C and 5HT2 receptors in initiating its biological effects. These observations indicate that guanine nucleotide-binding protein (G protein)-coupled receptors can exhibit high affinity for neurotransmitters in both the free receptor and the G protein-coupled states and that receptors exhibiting this property may represent a novel subfamily of G protein-coupled receptors.


Cyclic AMP potentiates receptor-stimulated phosphoinositide hydrolysis in human neuroepithelioma cells.

A stimulatory role for cAMP in the regulation of receptor-activated phosphoinositide hydrolysis has been examined in human SK-N-MCIXC and SK-N-MCIIE neuroepithelioma cells. The addition of optimal concentrations of oxotremorine-M, norepinephrine, endothelin-1, and ATP enhanced the release of inositol phosphates by 2-9-fold after activation of muscarinic, alpha 1-adrenergic, endothelin, and P2 nucleotide receptors, respectively. All combinations of these agonists elicited a release of inositol phosphates that was at least additive. However, the combined presence of oxotremorine-M and norepinephrine resulted in a phosphoinositide hydrolysis that was 30% greater than additive. This potentiation of inositol lipid hydrolysis resulted from an increased activity of the muscarinic receptor after the addition or norepinephrine and persisted after alpha 1-adrenergic receptor blockade. The enhancement of muscarinic receptor-stimulated inositol phosphate release could be quantitatively mimicked by inclusion of the beta-adrenergic agonist isoproterenol (EC50 approximately 0.1 microM), but not by alpha 1- or alpha 2-adrenergic agonists. Potentiation of oxotremorine-M-stimulated inositol lipid hydrolysis observed in the presence of either norepinephrine or isoproterenol was reduced in the absence of added Ca2+. Addition of either norepinephrine or isoproterenol to SK-N-MCIXC cells also resulted in a 16-fold increase in cAMP concentration. Although the cell-permeant 8-chloro-4-phenylthio-cAMP had a small inhibitory effect on basal inositol phosphate release, its inclusion resulted in a 19-31% enhancement of muscarinic, endothelin, ATP, and alpha 1-adrenergic receptor-stimulated phosphoinositide hydrolysis. We conclude 1) that, in SK-N-MCIXC cells, the addition of beta-adrenergic agonists selectively enhances muscarinic receptor-stimulated phosphoinositide hydrolysis through a cAMP-dependent process and 2) that the ability of exogenously added cAMP to enhance the activation of all four inositol lipid-linked receptors indicates that the effects of cAMP on inositol lipid hydrolysis are compartmentalized in these cells.


Preferential block of T-type calcium channels by neuroleptics in neural crest-derived rat and human C cell lines.

We have used the whole-cell version of the patch-clamp technique to analyze the inhibition of Ca2+ currents by antipsychotic agents in neural crest-derived rat and human thyroid C cell lines. Diphenylbutylpiperidine (DPBP) antipsychotics, including penfluridol and fluspirilene, potently and preferentially block T-type Ca2+ current in the rat medullary thyroid carcinoma 6-23 (clone 6) cell line. When step depolarizations were applied at 0.1 Hz from a holding potential of -80 mV, with 10 mM Ca2+ as the charge carrier, the DPBP penfluridol inhibited T-type current with an IC50 of 224 nM. High voltage-activated L and N currents were less potently blocked. At a concentration of 500 nM, penfluridol inhibited 78.0 +/- 2.3% (n = 29) of inactivating T-type Ca2+ current, whereas the sustained high voltage-activated current was reduced by 25.6 +/- 3.5% (n = 28). Block of T-type current by penfluridol was enhanced by depolarizing test pulses applied at frequencies above 0.03 Hz. The use-dependent component of block was largely reversed by pulse-free periods at -80 mV. T-type Ca2+ channels in the human TT C cell line were blocked by penfluridol, and the potency was enhanced by reduction of extracellular Ca2+. Non-DPBP antipsychotics, including haloperidol, clozapine, and thioridazine, also blocked T-type channels, but these were 20-100 times less potent than the DPBPs. These results identify the DPBPs as a new class of organic Ca2+ channel antagonists, which are distinctive in their ability to preferentially block T-type channels. These agents will be useful in defining the function of T channels in various excitable cells. Their potent block of T-type Ca2+ channels, which would be enhanced in rapidly firing cells, suggests that this action may be relevant to the therapeutic or toxic effects of these drugs when used in clinical pharmacology.


Theoretical studies on the histamine H2 receptor: molecular mechanism of action of antagonists.

The previously defined sites in the histamine H2 receptor model [Mol. Pharmacol. 40:980-987 (1991)] were used to elucidate the pharmacological mechanism of action of compounds that act as antagonists at the receptor. In this model, a formate anion is used both as the negative site at which the histamine cation is anchored to the receptor and as a proton acceptor site. An ammonium cation is used as a proton donor site. The proposed model of recognition of cimetidine, tiotidine, and ranitidine suggests that the monocationic form of the antagonists is the most favorable species to bind the receptor. Moreover, the mode of recognition follows the same trends obtained for compounds that act as agonists; the protonated site of the molecule, i.e., imidazolium in cimetidine, guanidinium in tiotidine, or substituted ammonium in ranitidine, anchors at the negative site of the receptor, whereas the nonbasic part, i.e., cyanoguanidine in cimetidine and tiotidine and nitrodiaminoethene in ranitidine, is located between the proton donor and acceptor sites. An energetic analysis of the interaction between the antagonists and the receptor model, including the energies of ligand desolvation, shows that histamine cannot compete effectively with cimetidine, tiotidine, or ranitidine for binding to the H2 receptor. The predicted order of antagonist potencies, based on differences of formation enthalpies (delta delta H1), reproduces qualitatively the experimental rank order.


Typing of human papillomaviruses by polymerase chain reaction amplification with L1 consensus primers and RFLP analysis.

Human papillomaviruses (HPV) cause benign and malignant lesions of the epithelial and mucosal surfaces. Certain virus types are associated with cervical carcinomas, while others are associated with benign condylomata. We have developed a rapid method for determining HPV type that is based on restriction fragment length polymorphism (RFLP) analysis within the L1 region of HPVs that is amplified by PCR using the consensus primers described by Manos et al. Analysis of the product generated by PCR amplification of plasmids containing cloned HPV genomes and of 88 clinical specimens, known to contain HPV viral DNA by previous hybridization analysis, revealed that this method is useful for typing HPV sequences amplified from a variety of sources including cervical lavages, fresh tissue, and paraffin-embedded formalin-fixed biopsy material. The method can differentiate between most known types of HPV and discriminate between infections with single, multiple or novel HPV types. A high correlation (86%) was obtained when this method was compared with PCR amplification and Southern blot hybridization analysis of PCR product, or Southern blot hybridization analysis of total genomic DNA. Differences in typing occurred mostly for specimens that contained multiple or new/unknown HPV types. However, RFLP typing easily identified repeated patterns for new HPV types that were not detected by the other methods. In summary, PCR-RFLP typing is a sensitive and specific method to identify and characterize rapidly HPV DNA in clinical specimens from a variety of sources.


Interactions between valproate, glutamate, aspartate, and GABA with respect to uptake in astroglial primary cultures.

Astrocytes have been proposed to regulate the extracellular space in the brain, even if rather little is known about their specific functions. One possibility for obtaining more knowledge on the functions of astroglial cells is to examine how they respond on exposure to pharmacological agents. Na(+)-valproate is an anticonvulsive drug which is used in the treatment of several types of epilepsy. The mechanisms of action of the drug are not fully understood, but the GABA-ergic system, both in neurons and astrocytes, has been shown to be affected. In the present study, the effects of valproate were investigated on astroglial cells in primary cultures from newborn rat cerebral cortex. The transport of the drug itself and its effects on the transport of the amino acid transmitters glutamate, aspartate and gamma-aminobutyric acid (GABA) into astrocytes were examined. The [3H]valproate transport into the astrocytes was increased after exposure to L-glutamate but not L-aspartate. On the other hand, after acute exposure for the drug, the transport of [3H]L-glutamate and [3H]L-aspartate decreased, as also did the affinity but not the transport capacity for the [3H]GABA uptake. However, after 5 days chronic valproate exposure, no effects could be seen on the uptake kinetics of L-glutamate or L-aspartate. For GABA, the affinity decreased, while the transport capacity remained unchanged compared with controls. The results showed that valproate, glutamate, aspartate and GABA were capable of interacting significantly with each others transport into the astrocytes.


High-affinity transport of choline and amino acid neurotransmitters in synaptosomes from brain regions after lesioning the nucleus basalis magnocellularis of young and aged rats.

Bilateral lesion of the nucleus basalis with ibotenic acid infusions in young and aged rats results in the degeneration of cholinergic neurons which innervate the cortex. As expected, high-affinity uptake of choline was decreased in the frontal cortex subsequent to the lesion. Twenty one days after surgery there was a significantly decrease of the transport rate of GABA, glutamate and glycine in the frontal cortex of young rats, but those activities showed a recovery six months after lesion. On the contrary, 12-month old rats lesioned with the same experimental protocol showed no recovery of the transport rates in the frontal cortex. Uptake of choline, GABA, glutamate and glycine has also been studied in other areas of the brain, namely, hippocampus, olfactory bulb and cerebellum. The present results suggest that lesioning the nucleus basalis of rats led to a more effective and permanent impairment of some biochemical functions of the brain, when compared to young lesioned animals, and also suggest a functional relationship between the nucleus basalis and other areas of the brain.


A non-linear haemodynamic model for the arterial pulsatile component of the intracranial pulse wave.

An indication that pressure pulses in cerebral arteries may play a role in the configuration of intracranial pressure pulsations is given by the observation that vasospasm of cerebral arteries narrows the amplitude of the intracranial pressure wave. The present work develops a mathematical model for the transmission of arterial pressure pulses across the compliant arterial wall to the surrounding intracranial space. Compliance of both the arterial segment and the intracranial space are considered. So as to retain accuracy at higher values of the mean intracranial pressure, a physiological range in which pulse transmission is enhanced due to lower pressure gradients but intracranial compliance is not necessarily decreased, a logistic fit is used to model the intracranial pressure-volume relationship. A sequence of approximations (with error bounds) is obtained for the induced intracranial pressure pulse amplitude as a function of arterial pulse amplitude, mean transmural pressure, and mean intracranial pressure. It is found that at higher mean intracranial pressures, where the usual exponential assumption for the intracranial pressure-volume curve loses validity, the amplitude of the transmitted arterial pressure pulse depends non-linearly on the mean intracranial pressure.


Capillary filling analysis by digital subtraction angiography for vertebro-basilar insufficiency.

Vertebro-basilar insufficiency (VBI) is a vague clinical entity including several symptoms such as faintness, dizziness, vertigo. Millikan and Siekert reported a 'syndrome of intermittent insufficiency of basilar arterial system'. But vascular abnormalities responsible for such symptoms are often hardly diagnosed by conventional angiography, because vertebro-basilar artery systems have many kinds of anomalous congenital origins. Conventional angiography gives us arterial informations such as stenosis, occlusion and malformations, but it often fails to reveal capillary perfusions because of its relatively poor density resolution. Digital subtraction angiography (DSA) is considered to have improved density resolution, and it may enable us to detect vascular perfusions more sensitively in the capillary phase. In this study, we evaluated the usefulness of the capillary filling analysis in digital subtraction angiography for diagnosis of VBI.


Spontaneous symmetry breaking and the onset of chaos in a muscle model.

The Hill length-tension curve of a muscle fibre is not linear. This had led us to investigate the behaviour of a model muscle sarcomere. The muscle is modelled as an oscillator of mass m subject to a nonlinear restoring force, a periodic external driving force and friction. We have found that this simple, idealized model exhibits spontaneous symmetry breaking and transition to chaos via a period doubling sequence. This result suggests that the nonlinearity in the length-tension curve of a muscle fibre could be responsible for irregular temporal behaviour and muscle tremor.


Reduced latency of the visual evoked cortical response following cryogenic injury to the cerebral cortex--a neuroexcitatory phenomenon.

Changes in the latency of visual cortical evoked responses (VER) were studied in rats subjected to cryogenic injury of the cerebral cortex. Four hours after cold injury the animals revealed a significant reduction of VER latency, which lasted approximately one week, with maximal reduction in latency occurring after 3 days. A potential role of excitotoxic amino acids in this phenomenon was tested by direct application of glutamate to the exposed cerebral cortex of the control rat and by administration of MK-801, antagonist of the NMDA receptor, in rats subjected previously to cryogenic injury and displaying a significant reduction in the VER latency. The direct application of glutamate to the cortex resulted in a decrease of the VER latency similar in magnitude to that observed after cold injury and this effect could repeatedly be demonstrated after washing out the initial application of the glutamate. The administration of MK-801 in animals subjected previously to cryogenic injury produced, within 5 minutes, reversion of reduced VER latencies. The maximal prolongation of latency occurred 30 min after MK-801 administration and reached in some cases latency values greater than in controls. Reduced latencies, corresponding to those observed originally, reappeared within 2 to 4 hours. Our studies suggest that the described reductions in the VER latencies are related to cortical areas of hyperexcitation due to excessive release of neuroexcitatory transmitters.


Mutations in transmembrane domain of c-erbB-2 gene in human malignant tumours of the central nervous system.

Point mutations in the transmembrane domain of c-erbB-2 gene in human brain tumours were studied by DNA amplification with the polymerase chain reaction method. Amplified gene fragments in M13 phage vector were cloned, and subsequent nucleotide sequences were determined. Studied specimens were 10 human malignant and 3 human benign tumours of the central nervous system, and a normal human placenta. In malignant tissues, Val-to-Glu mutation that induces transforming activity of c-erbB-2 did not appear to codon 659 of c-erbB-2. In malignant tissues, many other types of mutations appeared in low frequency, either at codon 659 or other positions of the transmembrane domain of c-erbB-2. The ratio of mutated genes to normal genes was very low in all specimens of malignant tumours. The point mutations were not observed in benign brain tumour or normal human placental tissues. The transmembrane domain of c-erbB-2 may have several highly mutable hot spots, where brain tumour tissues show a predilection for point mutation.


Management of pineal region tumours.

Pineal region tumours represent a colourful, challenging peculiarity of brain pathology. Views on their management are still much divided and controversial. Data of fifty patients with the whole palette of these tumours seen in the National Institute of Neurosurgery have been analysed in view of the result of management versus histology of these tumours. Findings of tumour marker studies have not at all been conclusive in predicting histology and outcome, however, cytology of the cerebrospinal fluid (CSF), if positive, pointed toward a very gloomy management result in all cases. Merits of infratentorial-supracerebellar, occipito-transtentorial approaches of direct surgery, palliative interventions and their timing, as well as that of irradiation are discussed in comparison with opinions and arguments from the literature. Shunt procedures alone proved to be dangerous in some cases by evoking haemorrhagic complications. In carefully selected cases microsurgical intervention gave the best possible results in expansively growing pineal region tumours. There is still place for irradiation and chemotherapy, again, in certain types of mass lesions.


Decreased visual evoked cortical response latency associated with cerebral ischaemia in the gerbil.

The observation of Xu et al. concerning reduction in latency of the visual evoked responses (VER) following cortical cryogenic injury, prompted us to ascertain whether similar VER changes could be demonstrable after ischaemic brain injury, especially, since both conditions have in common involvement of neuroexcitatory mechanisms. In our study, the Mongolian gerbils, which were subjected to 10 min bilateral carotid occlusion ischaemia, revealed decreased latency of the VER, with the peak of latency reduction between 4 and 7 h. An almost immediate decrease in VER latency was observed when glutamate was directly applied to the pial surface of the brain. These observations indicate that the reduction of VER latency may be related to neuroexcitation induced by release of excitatory amino acids, the latter constituting a widespread phenomenon, concomitant with brain injuries of various aetiologies.


Infantile acute encephalopathy with combined symmetrical hypodensities in the thalami and the putamen on computed tomography.

An eight-month-old boy with clinical features of acute encephalopathy with symmetrical low-density areas in the thalami and the putamen on computed tomography is presented. These particular computed tomography features suggest potential aetiology common to acute encephalopathy with low-density areas in the thalami and infantile bilateral striatal necrosis with an acute onset. The therapeutic consideration of these conditions is also discussed.


Dielectric measurement of cerebral water content using a Network Analyzer.

At present, no practical method exists for monitoring the progression and severity of cerebral oedema in a clinical setting on a continuous basis. In search for such a method, we investigated the electrical characteristics of cerebral tissue at microwave frequencies to quantify cerebral oedema. The dielectric constants of normal and oedematous canine cerebral white matter were measured using a Network Analyzer and then compared to the tissue's water content. In addition, salt infiltration and time elapsed after excision of the tissue were examined to determine their effects on the measurements. The water content and dielectric constant of the white matter were linearly related (correlation coefficient, r = 0.903), comparable to results obtained with a Time Domain Reflectometer in previous research. The Network Analyzer, however, is a more robust measurement device and, because of this, can potentially be used for long term measurements. Further, it was found that neither an increased tissue salt content nor the amount of time after excision of the tissue significantly affected the results. This indicates that the dielectric constant of cerebral white matter is mainly a function of the tissue's water content.


Microsurgical anatomy of the lower basilar artery.

This study was designed to study the microvascular anatomy of the basilar artery between the superior cerebellar artery and the vertebrobasilar junction (i.e. the lower basilar artery). Twenty unfixed brains were injected with silicone rubber solution and studied with a Zeiss OPMI microscope. The length of this segment of the basilar artery was 28.1 + 1.35 mm and its course was straight in 9 (45%) brains, curved in 7 (35%) and tortuous in 4 (20%). The total number of perforators found in 20 brains was 340 with an average of 17 per brain. Of these, 118 (34.7%) were median and 222 (65.2%) were lateral. Median branches had a mean length of 5.8 + 1.25 mm, whereas left and right lateral branches had a mean length of 16 + 1.25 mm and 16 + 1.58 mm respectively.


Characterization of human gliomas by a monoclonal antibody both on tissue culture and paraffin-embedded sections.

A monoclonal antibody designated OITIC3-11 was produced against GFAP positive human glioblastoma multiforme tumour cells. The specificity of the monoclonal antibody was tested on different types of human brain tumours and on normal adult brain both on tissue cultures and paraffin-embedded sections. The OITIC3-11 monoclonal antibody reacted with 16 of 18 malignant and 1 of 6 benign gliomas but did not react with meningioma, pituitary adenoma, metastatic brain tumours and normal adult brain tissue.


Detection and partial purification of ischaemia-related neurotrophic activity in the periinfarcted brain tissue.

In the rat model of middle cerebral artery (MCA) occlusion, axons originating from the ipsilateral cortical and thalamic neurons are injured by ischaemia. The cortical neurons survive thereafter without retrograde degeneration, but thalamic neurons slowly die because of retrograde degeneration. The fate of these two neurons is remarkably different and may be related to neurotrophic activity induced by ischaemia. We detected ischaemia-related neurotrophic activity, and partially purified the factor. Tissue samples were obtained from the cortex adjacent to the infarction and contralateral corresponding site at 4, 8 and 12 days after occlusion of the MCA. They were homogenated with a culture medium and ultracentrifuged. The supernatant was obtained and used for neurotrophic assay. Foetal cortical neurons were obtained from 17 days rat embryo and cultured. Neurotrophic activity was assayed by applying tissue extract to the culture medium. Application of periischaemic cortical extract obtained at 8 and 12 days after ischaemia improved neuronal survival by 50% and 200% as compared to contralateral cortical extract, respectively. The activity was not detectable at 4 days after ischaemia. The neurotrophic activity disappeared by heating the extract at 90 degrees C for 10 min. We fractionated the extract by saturated ammonium sulphate precipitation, followed by gel-filtered with Superose 12 column. The neurotrophic activity was detected in the precipitation of 30 to 60% saturation fraction of ammonium sulphate. With gel-filtration we separated neurotrophic activity in several fractions, which included marker proteins of 8, 22 and 30 kilodaltons. The activities were only detected in the lesioned side but not in the contralateral side.(ABSTRACT TRUNCATED AT 250 WORDS)


Treatment of vasospasm by balloon angioplasty: experimental studies and clinical experiences.

The vasodilation mode and degree of the invasion caused by balloon angioplasty were experimentally examined. Assessment by light microscopy and scanning electron microscopy demonstrated that the invasion to the implanted arterial wall, taken from a patient who died from vasospasm, was minimized by the use of the balloon under the condition at 1 atm, 10 times for 10 seconds. Furthermore, we applied angioplasty to eight patients who developed severe vasospasm after subarachnoid haemorrhage, and five showed improvement in neurophysiological (transcranial Doppler sonography), neuroradiological, and clinical examinations. In addition, blood vessels obtained from one patient who died 10 days after angioplasty, demonstrated similar findings to those of the experimental studies. It can be said that angioplasty will be one of the effective therapeutic methods to manage vasospasm when it is applied under the conditions mentioned above.


Cerebrospinal fluid beta-2-microglobulin in multiple sclerosis and AIDS dementia complex.

Cerebrospinal fluid (CSF) and serum concentrations of beta-2-microglobulin (beta-2-m) were evaluated in 19 patients with clinically definite multiple sclerosis (MS), in 21 with AIDS dementia complex (ADC), and in 20 subjects with other neurological diseases (OND). CSF beta-2-m and CSF/serum beta-2-m ratio were significantly higher in the patients with ADC than in the MS and OND patients. The CSF and serum levels of beta-2-m in MS patients were not significantly different from those of OND patients. These findings indicate that CSF beta-2-m and CSF/serum ratio may be a useful marker in the diagnosis of ADC. In MS patients the beta-2-m CSF determinations are of no value.


The diagnostic utility of elevation in cerebrospinal fluid beta 2-microglobulin in HIV-1 dementia. Multicenter AIDS Cohort Study.

We measured serum and CSF beta 2-microglobulin (beta 2M) levels in HIV-1 seropositive individuals with and without dementia to determine the frequency and diagnostic utility of elevation of CSF beta 2M. We compared 34 samples from 27 patients with HIV-1 dementia with 110 samples from 54 HIV-1 seropositive participants in the Multicenter AIDS Cohort Study, none of whom had progressive dementia. Neurosyphilis and CNS opportunistic processes were excluded in all subjects. We stratified the nondemented subjects by duration of HIV seropositivity and peripheral blood CD4 count. Compared with the nondemented group, demented subjects had significantly higher CSF total protein, IgG%, and CSF albumin/serum albumin ratios. A highly significant association was found between elevated CSF beta 2M and reduced CD4 count (p less than 0.0001). No significant differences were noted between the demented and nondemented groups in CSF WBC count or in the frequency of CSF HIV-1 isolation. The mean CSF beta 2M was 1.9 mg/l in the nondemented subjects compared with 4.2 mg/l in those with dementia (p less than 0.0001). We derived a cutoff of 3.8 mg/l from the distribution of CSF beta 2M in the nondemented group. The determination of CSF beta 2M had a sensitivity of 44%, specificity of 90%, and a positive predictive value of 88% for diagnosis of HIV dementia when compared with nondemented subjects with CD4 counts less than 200. In those without dementia, there was a strong correlation between serum and CSF beta 2M (r = 0.50, p less than 0.0001), but in demented subjects CSF beta 2M was elevated independently of serum levels, suggesting that CSF beta 2M is produced within the brain in HIV dementia. In the absence of CNS opportunistic processes, elevated CSF beta 2M greater than 3.8 mg/l is a clinically useful marker for HIV dementia.


Bilateral localized orbital neurofibromas.

The authors report on a 30-year-old man who presented with progressive bilateral exophthalmos over a 2-year period. Computed tomography showed large heterogeneous masses in the superior aspect of both orbits. Excisional biopsy via bilateral lateral orbitotomies showed the tumors to be well-circumscribed, relatively avascular, localized neurofibromas. The patient had several features suggestive of multiple endocrine neoplasia type IIB, including Marfanoid habitus, enlarged corneal nerves, thickened lips, and mucosal neuromas. Localized neurofibromas are rare in the orbit and, unlike plexiform neurofibromas, are not typically associated with von Recklinghausen's neurofibromatosis. Bilaterality of such localized neurofibromas has not been previously reported. Recognition of ophthalmic lesions suggestive of multiple endocrine neoplasia IIB should prompt evaluation for systemic manifestations of this disorder.


Prenatal diagnosis of autosomal dominant polycystic kidney disease using flanking DNA markers and the polymerase chain reaction.

A prenatal diagnosis was carried out on a 9-week-old fetus at risk for autosomal dominant polycystic kidney disease (ADPKD). Ten members of the family were previously typed using five DNA markers linked to the PKD1 locus on chromosome 16, and one marker linked to the putative PKD2 locus on chromosome 2. The polymerase chain reaction (PCR) was used to amplify the D16S125 locus. Pairwise and multipoint lod scores indicated that the family was most likely segregating a PKD1 mutation. The fetus inherited the disease haplotype from the affected parent. Diagnostic accuracy was greater than 99 per cent, taking into account the possibility of genetic heterogeneity.


Immunocytochemical and ultrastructural abnormalities of islet tissue in patients with VIP-producing tumors of the pancreas.

Nontumoral endocrine pancreas from three patients with malignant vasoactive intestinal polypeptide (VIP)-omas and the Verner-Morrison (watery diarrhea, hypokalemia, and hypoachlorhydria) syndrome was studied immunocytochemically, ultrastructurally, and morphometrically. Compared with normal islets from control subjects, those of the VIPoma-associated pancreas showed a decrease of immunoreactive insulin in B-cells associated with cytological features indicative of enhanced insulin synthesis and secretion and an increase in the number of immunoreactive somatostatin- and pancreatic polypeptide-containing cells, in the absence of ultrastructural signs of modified secretory activity. No substantial alterations of A-cells were observed. In addition, images of diffuse de novo formation of ducts and islet tissue were often found. Possible mechanisms involved in determining the above changes are discussed.


Etonitazene delivered orally serves as a reinforcer for Lewis but not Fischer 344 rats.

Oral etonitazene self-administration was systematically investigated in two inbred strains of rats, Lewis (LEW) and Fischer 344 (F344). For LEW rats, etonitazene maintained higher rates of lever pressing and was consumed in larger volumes than the water vehicle when the reinforcement schedule was fixed ratio (FR) 8. In contrast, with F344 rats responding did not systematically exceed water values at any etonitazene concentration. LEW rats also drank substantially more etonitazene than F344 rats, and at FR 8 only LEW rats showed the typical inverted U-shaped function between etonitazene concentration and number of responses. For the LEW strain, response rate increased as FR size increased from FR 1 to FR 2 and FR 4, but decreased at FR 8. For the F344 strain, as FR size increased response rate showed small increases, but the response rates were far lower than those of the LEW strain. The results support the conclusion that etonitazene was an effective reinforcer for LEW but not F344 rats. These findings demonstrate genetic differences in opioid reinforcement of operant behavior and indicate that genotype can be an important determinant of whether etonitazene serves as a reinforcer.


Effects of tizanidine on morphine physical dependence: attenuation and intensification.

It has previously been shown that subchronic and acute administration of L-asparaginase and glutaminase inhibitors D-Aspartic acid (D-ASP) and prolyl-leucyl-glycinamide (PLG) intensifies and attenuates morphine (M) physical dependence, respectively, by the inhibition of ASP and glutamic acid (GLU) production, and subsequently their normal releases. Tizanidine (TIZ) has long been known to be an alpha 2-adrenoceptor agonist and inhibitor of ASP and GLU release. Therefore, in this study TIZ has been administered subchronically during the development of M physical dependence to rats in which M-containing pellets had been implanted or acutely 30 min before naloxone (NL)-induced abstinence syndrome. The subchronic administration of TIZ intensified NL-precipitated abstinence syndrome whereas its acute administration attenuated it, as did D-ASP and PLG. On the other hand, TIZ added into the medium prevented the in vitro M-dependent-made guinea pig ileum from contracting following NL application. Furthermore, TIZ stopped the already started contraction by NL of the M-dependent ileum, which completely relaxed later. These effects of TIZ on M-dependent ileum were antagonized by the alpha 2-adrenoceptor antagonist yohimbine. The intensification by subchronic TIZ administration of abstinence syndrome was attributed to the lesser release of ASP and GLU, which resulted in the larger blockade of M of ASPergic/GLUergic receptors due to the lesser release of their endogenous agonist ASP and GLU and consequently the higher upregulation of the receptors. The attenuation by acute TIZ administration of NL-precipitated abstinence syndrome was explained with lesser release of ASP and GLU and concomitantly the lesser stimulation of the receptors.(ABSTRACT TRUNCATED AT 250 WORDS)


Dynorphin A(1-13) preferentially inhibits behaviors induced by the D2 dopamine agonist RU 24213 but not by the D1 dopamine agonist SK&F 38393.

The effects of dynorphin A(1-13) on the D1 dopamine agonist SK&F 38393- and the D2 dopamine agonist RU 24213-induced behavioral alterations in the mouse were determined by using multidimensional behavioral analyses based upon a capacitance system. Although dynorphin A(1-13) (3.0 or 12.5 micrograms) alone did not produce any significant effects on behaviors, the peptide (12.5 micrograms) caused an inhibitory effect on the RU 24213 (3.0 mg/kg)-induced increase in behavioral patterns such as linear locomotion and circling except rearing and grooming behaviors. The antagonistic effects of dynorphin A(1-313) (12.5 micrograms) were fully reversed by the opioid antagonist M(r) 2266 (10.0 mg/kg). However, dynorphin A(1-13) (3.0 or 12.5 micrograms) failed to affect behaviors elicited by SK&F 38393 (10.0 mg/kg). These results suggest that dynorphin A(1-13) plays an inhibitory role in behaviors induced by the D2 dopamine agonist but not by the D1 dopamine agonist, possibly through the mediation of kappa-opioid receptors.


Sexual segregation in infancy and bi-directional benzodiazepine effects on hot-plate response and neophobia in adult mice.

In the present experiment, the hypothesis that rearing animals in conditions of sexual segregation in infancy (ISS) would affect their adult behavioral reactivity to drug or environmental challenges was tested. Outbred Swiss CD-1 mouse litters were reduced at birth to six pups according to three conditions: MM (all males), MF (sex-balanced composition), and FF (all females). At weaning (day 21), all mice were rehoused in unisexual groups. At adulthood (day 70), animals were challenged either with BDZ agonist chlordiazepoxide (CDP at 2.5- or 5.0-mg/kg dose) or BDZ receptor partial inverse agonist Ro 15-3505 (RO at 3-, 10-, or 30-mg/kg dose) and assessed in sequence for pain reactivity in a hot-plate apparatus (set at 55 +/- 1 degrees C), for locomotor activity in a Varimex apparatus, and finally for neophobia level by measuring the latency to first approach a novel object. As concerns the hot-plate test, lick latency was significantly shortened in MF females receiving CDP (5.0 mg/kg), while RO was either ineffective in MF females or induced a prominent dose-dependent analgesia in FF females. Activity was decreased by CDP (2.5 mg/kg) and enhanced by RO (3.0 mg/kg). For latency to approach a novel object, males as a whole exhibited shorter times than females. Mixed-sex animals of both sexes were less fearful, being also more explorative than their corresponding unisexually reared groups. In particular, MF males receiving either a 5.0-mg/kg CDP dose or a 3.0-mg/kg RO dose explored the object more often than MM males.(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of atipamezole, an alpha 2-adrenoceptor antagonist, on the performance of rats in a five-choice serial reaction time task.

The present study investigates whether pharmacological activation of the noradrenergic system improves attention. The effects of atipamezole, a potent alpha 2-adrenoceptor antagonist, on the performance of adult male rats in the five-choice serial reaction time task were studied. Before drug testings, food-deprived rats were trained to detect and respond to brief flashes of light presented randomly by the computer in one of five spatially diverse locations until a stable level of performance had been reached (about 3 months). Single-dose administration of atipamezole (0.03-3.0 mg/kg) slightly increased the number of premature and perseverative responses during the intertrial interval and slightly decreased the reaction times to incorrect responses, indicating increased behavioral activation. Atipamezole did not affect discriminative accuracy. However, in a subpopulation of rats with the poorest discriminative accuracy according to pretest performance seven of eight rats improved their discriminative accuracy when treated with 0.3 mg/kg atipamezole as compared to controls. At the other doses tested, no improvement was found. The present results suggest that acute administration of atipamezole, and alpha 2-adrenoceptor antagonist, slightly increases behavioral activation, although the effects on baseline performance in the task measuring selective attention are modest.


Cognitive-behavioral therapy for benzodiazepine discontinuation in panic disorder patients.

The discontinuation of benzodiazepine treatment in patients with panic disorder may be associated with emergent withdrawal and anxiety symptoms, relapse of panic, and the inability to complete benzodiazepine taper. Although some patients may respond to slow taper strategies or the use of pharmacologic adjuncts, many continue to experience significant difficulties during benzodiazepine discontinuation. This paper presents a cognitive-behavioral conceptualization of benzodiazepine discontinuation difficulties, emphasizing "fear of fear" cycles. From this perspective the discontinuation process is seen as exposing panic disorder patients to somatic sensations associated with panic at a time when there is both increased anxiety and concern about re-emergence or worsening of panic episodes. As a consequence, patients may re-enter a cycle of catastrophic interpretations of symptoms, increased vigilance and fear, and panic. Cognitive-behavioral interventions may ameliorate discontinuation-associated difficulties and prevent the return of the panic disorder. Preliminary data supporting the efficacy of these interventions are described.


Schizophrenia and the D1 receptor: focus on negative symptoms.

Negative symptoms have been associated with structural impairment in the PFC, and hypothesized to arise from a central hypodopaminergic substrate. Corticofugal PFC neurons, which are inhibited by VTA DA innervation, exert a tonic excitatory modulation on DA activity in the NAS. Lesions of ascending DA forebrain projections "uncouple" the functional link between D1 and D2 receptors, permitting independent activation of D1 sites in generating behavioral output. A previously identified absence of this D1/D2 link in schizophrenic brain suggests that functional activation of PFC D1 receptors may induce hyperinhibition of descending corticofugal efferents to the NAS. Consequent hypoactivity of DA in the NAS is proposed to give rise to negative symptoms of schizophrenia, and low dose DA agonist treatments may mimic behavioral features of this symptom profile via direct PFC D1 stimulation. It follows that clozapine's efficacy for negative symptoms may be attributable, in part, to blockade of PFC D1 receptors, with subsequent enhancement of glutamate-facilitated NAS DA activity.


The future of 5-HT1A receptor agonists. (Aryl-piperazine derivatives).

At present the dominant position among anti-anxiety medications has changed from meprobamate to the benzodiazepine derivatives. In order to avoid benzodiazepine's (BZ) undesirable side effects such as impairment of psycho-motor function, memory impairment, low dose dependence and withdrawal symptoms, a third generation anxiolytic agent, buspirone, the focus of the aryl-piperazine group of anti-anxiety agents, has been introduced recently. Aryl-piperazine derivatives work as 5-HT1A receptor partial agonists and are known as serotonin normalizers. Therefore, they are expected to have not only an anxiolytic function but also an anti-depressant effect as well. A characteristic of the aryl-piperazine derivatives is that they have no sedative and muscle relaxant effects, and they do not have BZ's undesirable side-effects, especially in regard to withdrawal symptoms. However they have a rather weak anxiolytic action and a slow onset of action. Aryl-piperazine derivatives will not take the place of BZ, but the use of BZ and buspirone as bridge medications, making the most of the strong points of both, can be proposed as a way to compensate for their respective clisadvantages.


Regional glucose metabolism in schizophrenic patients before and during neuroleptic treatment.

Determination of regional glucose metabolism has been considered to be a tool to elucidate the mechanisms of action of neuroleptics. D2-dopamine antagonists seem to increase glucose consumption in dopamine innervated areas. Studies in humans do not give results in complete accordance with animal findings. In patients neuroleptic compounds and dopamine agonists probably increase and decrease striatal metabolism respectively. Changes in metabolism, especially in the right hemisphere may be coupled with improvement of the patients. Future research must be based on protocols specially designed for the study of drug effects.


Early serum levels of neuroleptics do not predict therapeutic response in schizophrenia.

Thirty-six acute schizophrenics were included in a 28-day open treatment study with the neuroleptic perazine. Peak serum levels of parent drug and its main inactive metabolite desmethyl-perazine were assessed 2 hours after an oral test dose given at the beginning of the study. Whereas peak levels of perazine were not significantly different in treatment responders and nonresponders, desmethyl-perazine was significantly higher in nonresponders. The ratio between desmethyl-perazine and perazine was not predictive of (non-) response to neuroleptic treatment in schizophrenia.


Identification of genetic susceptibility loci for insulin-dependent diabetes in Sudan.

In this study we report, for the first time, the molecular analysis of HLA-DR and DQ gene frequencies in a large cohort of well-characterized type 1 (insulin-dependent) diabetes mellitus (IDDM) patients (n = 72), and ethnically matched controls (n = 59) collected in sub-Saharan Africa. High molecular mass DNA was prepared and analysed in Southern blots and by oligonucleotide typing. We have shown a strong positive association between IDDM and the Asp 57- DQB1 allele *0201 (DQw2). A rare DR4, DQw2 haplotype was also identified at high frequency in the IDDM cohort. We can now confirm that the association between Asp 57- DQB1 alleles and IDDM, previously reported in ethnically diverse cohorts collected in Western Europe, North America, and South Asia, is also present in an IDDM cohort collected in Africa.


Experimental infection with a haemorrhage-causing Trypanosoma vivax in N'Dama and Boran cattle.

N'Dama cattle control experimental infections with clones of Trypanosoma congolense of varying degrees of virulence, but nothing is known about their capacity to control infections caused by highly virulent, East African stocks of T. vivax. Thus four N'Damas and four trypanosusceptible Borans were infected with a tsetse-transmitted stock of T. vivax IL2337. In Ayrshire cattle this stock is known to cause severe haemorrhagic disease. No differences were observed in the parasitaemia between the two groups. Both groups became anaemic. The mean packed cell volume fell to 16.8 +/- 5.0% in the N'Dama cattle and to 24.2 +/- 2.2% in the Borans on day 26 post infection. These differences were not significant. Antibody responses to invariant trypanosome antigens were analysed. No differences were observed between the groups in the pattern of recognition or the isotype elicited. Antibody bound to the surface of erythrocytes was occasionally detected. No anti-platelet activity was observed. The results show that N'Dama cattle, which are known to be resistant to disease caused by T. congolense and by T. vivax stocks from West Africa, were highly susceptible to an infection of T. vivax which causes acute haemorrhagic disease.


Suppression of T-cell responsiveness during tsetse-transmitted trypanosomiasis in cattle.

In the present study, we demonstrate that lymph node cells from cattle infected with T. congolense through tsetse fly challenge were unable to proliferate in vitro following activation with the T-cell mitogen Concanavalin A. This was associated with a simultaneous suppression of interleukin 2 (IL-2) production and interleukin 2 receptor (IL-2R) expression. However, the capacity of the cells to secrete interferon gamma following the mitogenic activation was not affected by the infection.


Arctic terrestrial ecosystem contamination.

Limited data have been collected on the presence of contaminants in the Arctic terrestrial ecosystem, with the exception of radioactive fallout from atmospheric weapons testing. Although southern and temperate biological systems have largely cleansed themselves of radioactive fallout deposited during the 1950s and 1960s, Arctic environments have not. Lichens accumulate radioactivity more than many other plants because of their large surface area and long life span; the presence and persistence of radioisotopes in the Arctic is of concern because of the lichen----reindeer----human ecosystem. Effective biological half-life of cesium 137 is reckoned to be substantially less than its physical half-life. The database on organochlorines in Canadian Arctic terrestrial mammals and birds is very limited, but indications are that the air/plant/animal contaminant pathway is the major route of these compounds into the terrestrial food chain. For terrestrial herbivores, the most abundant organochlorine is usually hexachlorobenzene followed by hexachlorocyclohexane isomers. PCB accumulation favours the hexachlorobiphenyl, pentachlorobiphenyl and heptachlorobiphenyl homologous series. The concentrations of the various classes of organochlorine compounds are substantially lower in terrestrial herbivore tissues than in marine mammal tissues. PCBs and DDT are the most abundant residues in peregrine falcons (a terrestrial carnivore) reaching average levels of 9.2 and 10.4 micrograms.g-1, respectively, more than 10 times higher than other organochlorines and higher than in marine mammals, including the polar bear. Contaminants from local sources include metals from mining activities, hydrocarbons and waste drilling fluids from oil and gas exploration and production, wastes from DEW line sites, naturally occurring radionuclides associated with uranium mineralization, and smoke containing SO2 and H2SO4 aerosol from the Smoking Hills at Cape Bathurst, N.W.T.


Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar.

The neural mechanisms underlying the high pressure neurologic syndrome (HPNS), which limit man's safe advance to extreme diving depths, are still unclear. This work was aimed at a better understanding of HPNS through study of brainstem auditory-evoked potentials (BAEP). BAEP were repeatedly recorded within 2 experimental chamber dives, Titan VIII (2 divers, maximum depth of 560 msw, compression time to bottom 109 h) and Titan XI (3 divers, maximum depth of 615 msw, compression time to bottom 240 h). Prolongation of the IV/V-complex occurred in 2 divers upon reaching 525 msw during Titan VIII compression and was accompanied by vestibular disturbances and amplitude increases of finger tremor. Both categories of changes--clinical signs and IV/V delay--gradually diminished during a 4-day stay at 545 msw, suggesting that they depended on excessive compression rates and insufficient acclimation time. Longer holding times at intermittent depths during Titan XI clearly reduced both HPNS symptoms and magnitude of prolongation of IV/V latencies. Wave I and wave III latency did not significantly change, pointing to a suppression of pontomesencephalic transmission. We infer that pressure suppresses synaptic transmission or triggers an increase of cortical or subcortical efferent inhibitory modulation of upper pontine and midbrain auditory afferents. Postdive controls revealed no persistent changes of BAEP measures in either the Titan VIII or XI divers.


Cerebral blood flow distribution during exposure to 5 bar oxygen in awake rats.

The regional cerebral blood flow (rCBF) and cardiac output (CO) were measured in conscious rats by the microsphere method during control, after 5 and 60 min at 5 bar O2, and 5 min after decompression to air. The arterial acid-base balance was essentially unchanged during hyperbaric O2 and after decompression, except for a slightly reduced CO2 and HCO3 during the O2 exposure. The heart rate (HR) fell at 1 bar O2, continued to fall during compression, and remained low. A marked HR rise occurred in air after decompression. The systolic arterial pressure (AP) increased, while mean AP was constant during the O2 exposure. The CO and total cerebral blood flow fell in proportion to the arterial O2 content increase. The rCBF was unevenly distributed in control, and fell to a disparate degree and remained low in some regions during O2 exposure. Due to the rCBF fall, the O2 supply was limited, the glucose supply was reduced, and CO2 and heat transport probably were limited, suggesting a labile metabolic state locally in the brain. After decompression, blood flow remained low in several regions, making hypoxia likely for a considerable time in several brain areas, whereas the rest of the brain had normalized or increased blood flow. The HR and systolic AP remained high for at least 30 min after decompression.


Xenon washout from the rabbit femur during short hyperbaric exposures.

133Xenon washout from the femora of 5 anesthetized rabbits was recorded during short hyperbaric exposures (3 atm abs). Equipment tests showed that the scintillation counter was heat sensitive. The recorded count rate from a constant source of 133xenon decreased during compression (temperature rose 5 degrees C) and increased during decompression (temperature fell 5 degrees C). When the scintillation counter was thermally insulated, the rate of xenon washout from the femur remained unchanged in all rabbits during these hyperbaric exposures. The conclusion is that the rate of xenon washout from the femur is not affected by changes in ambient pressure. As most scintillation counters are heat sensitive, it is possible that the previous report of such changes was erroneous and caused by heat sensitivity of the recording equipment.


Intravascular bubble composition in guinea pigs: a possible explanation for differences in decompression risk among different gases.

Differences in risk of decompression sickness (DCS) that have been observed among inert gases may reflect differences in gas solubility or diffusivity or both. A higher risk gas might generate a larger volume of evolved gas during decompression, thereby increasing the probability of DCS. If this hypothesis is correct, the composition of bubbles that develop during decompression should reflect such gas differences. Unanesthetized guinea pigs were compressed to depths ranging from 250 to 350 fsw with air, He-O2 (21% O2) or one of a number of N2-He-O2 or N2-Ar-O2 mixtures (21% O2). Animals were held at depth from 15 to 60 min, then decompressed slowly (60 fsw/min) or rapidly (less than 15 s) to 5 fsw. If severe DCS developed, as judged by changes in physiologic variables, death usually occurred quickly. Gas/blood samples were then immediately withdrawn from the right atrium or the inferior vena cava, and the gas phase analyzed for He, N2, Ar, O2, and CO2 via gas chromatography. Bubbles from all dives contained 5-9% CO2, 1-4% O2, with the balance inert gas. Bubbles after N2-He-O2 dives contained substantially more N2 than He (up to 1.9 times more) compared to the dive mixture; bubbles after N2-Ar-O2 dives contained more Ar than N2 (up to 1.8 times more). For N2-He-O2 dives, the actual inert gas makeup of bubbles was dependent on the time-at-depth and the decompression profile. Results may reflect differences among He, N2, and Ar in tissue solubility/diffusivity and gas exchange rates, and support the rank order of increasing DCS risk (He less than N2 less than Ar) and rate of gas exchange (N2 less than He) observed previously during rat dives.


Comparative bacteriological studies on summer mastitis in grazing cattle and pyogenes mastitis in stabled cattle in Denmark.

A total of 143 secretions from clinical cases of summer mastitis (SM) in grazing cattle and from 89 cases of pyogenes mastitis (PM) in stabled cattle were examined bacteriologically. The typical bacteriological finding was a mixed flora in which the predominant organisms were Actinomyces pyogenes (SM-70%, PM-85%), Peptostreptococcus indolicus (54%, 54%), a microaerophilic coccus (Stuart-Schwan coccus) (26%, 25%), Fusobacterium necrophorum biovar B (22%, 12%), Bacteroides melaninogenicus (20%, 9%) and Streptococcus dysgalactiae (21%, 5%). All except six cases occurred in non-lactating animals or within three weeks after parturition. The majority of animals (about 90%) had only one quarter affected and no differences in quarter distribution were observed between the two groups.


Identification of canine T-lymphocyte subsets with monoclonal antibodies.

A panel of five murine monoclonal antibodies to canine T-lymphocytes were produced. Antibodies 4.78, 12.125 and 8.358 reacted with approximately 18%, 39% and 60% peripheral blood lymphocytes, respectively. Two color flow cytometric analysis showed that lymphocytes expressing 1.140, 4.78, 8.53 and 12.125 were subsets of lymphocytes expressing 8.358. The lymphocytes expressing 8.358 were negative for surface immunoglobulin. The subsets defined by 1.140, 4.78 or 8.53, 12.125 were mutually exclusive and together account for most cells expressing 8.358 in the peripheral blood, spleen, and lymph node. In the thymus, approximately 47% cells were positive for both 1.140/4.78 and 8.53/12.125. SDS-PAGE analysis of radiolabelled thymus cell lysates demonstrated that antibodies 1.140 and 4.78 immunoprecipitated a 32,35 kd heterodimer under reducing conditions and 12.125 immunoprecipitated a single 56 kd chain under reducing and non-reducing conditions. Antibodies 8.53/12.125 and 1.140/4.78 react with canine lymphocyte populations that occur in proportions similar to lymphocytes expressing CD4 and CD8 like molecules in several primate and non-primate species. The molecules recognized by 12.125 and 1.140/4.78 were similar in size and subunit composition to human CD4 and CD8.


Development of the B- and T-cell compartments in porcine lymphoid organs from birth to adult life: an immunohistological approach.

Using immunohistological techniques, we studied the development over time of B- and T-cell compartments in the lymphoid organs of specific-pathogen-free pigs. Tissue samples were collected at various time-points, starting 2 days before the pigs were born until the pigs were 10 months old. The samples were collected from the spleen, thymus, peripheral lymph node, mesenteric lymph node, duodenum, jejunum, ileum, jejunal Peyer's patch and ileal Peyer's patch. Monoclonal antibodies specific to B- and T-cells were used to identify where the following cells were localized: IgM-B cells (cells positive to surface immunoglobulin), IgM-, IgG- and IgA-containing cells (cells positive to cytoplasmic immunoglobulin), and CD2-, CD4- and CD8-positive cells. The development of the B- and T-cell subpopulations in each organ was analysed. Two days before birth, most organs contained quantities of IgM-B cells. The spleen, lymph nodes, Peyer's patches and, notably, the thymus, contained some immunoglobulin-containing cells (Ig-CC); this finding indicates that pigs have cells that secrete immunoglobulins before birth. Just after birth, the incidence of Ig-CC increased in most organs; first IgM-CC increased, then either IgG- or IgA-CC increased, depending on the organ. T-cell development was observed clearly in spleen and in the lamina propria of the small intestine, in contrast to other organs, in which the T-cell compartments containing various T-cell subpopulations were well developed before birth. Comparison of the incidence of CD4+ and CD8+ cells showed that the CD4:CD8 ratio of these cells in the spleen, lymph nodes, Peyer's patches and small intestine is low, especially in adult pigs, compared with the CD4:CD8 ratio in other species. Weaning had little influence on the incidence of B- and T-cells in lymphoid organs. This study is the first immunohistological survey to describe the development of the major B- and T-cell subpopulations in various lymphoid organs of pigs, and it should be useful for future immunopathological and comparative immunological studies in pigs.


Induction of interdigitating reticulum cell-like differentiation in human monocytic leukemia cells by conditioned medium from IL-2-stimulated helper T-cells.

Monocytic leukemia (MoL) cells were obtained from the peripheral blood of a patient in whom the leukemic cells infiltrating various lymphoreticular organs exhibited features intermediate between interdigitating reticulum cells (IDC) and ordinary phagocytic macrophages, whereas the leukemic cells in the peripheral blood were essentially monocytic and lacked such features. Peripheral blood CD4+ T-cells were established as an interleukin-2-dependent T-cell line. When the MoL cells were exposed for a few days to conditioned medium from the T-cell line, they extended several dendritic cytoplasmic projections and became intensely positive for HLA-DR antigen, cytoplasmic S-100 beta protein, and CD1 antigen. Functionally, the conditioned medium significantly down-regulated Fc-mediated and Fc-independent phagocytic activities, and the levels of lysosomal enzymes such as lysozyme and nonspecific esterase in the MoL cells. Moreover, the conditioned medium significantly up-regulated the accessory cell function of the MoL cells as measured by the primary allogenic mixed leukocyte reaction (MLR). Furthermore, the conditioned medium significantly down-regulated the expression of CD14 antigen. Biochemical analysis indicated that the factor responsible for these changes is a protein which is distinct from known human cytokines and whose molecular weight is approximately 31 kDa. These findings suggest that IDC are closely related the monocytic lineage and that helper T-cells play an important role in constructing the microenvironment of T-lymphoid tissues which is necessary for the differentiation and maturation of IDC.


Immune-mediated interactions during macrophage development in non-Hodgkin's lymphoma.

As part of an investigation of mononuclear phagocytes in malignant lymphoma, measurement of immune-mediated erythrophagocytosis and rosette formation was carried out on cells grown in suspension culture at the monocyte (Day 0) and macrophage (Day 6) stages; the culture medium contained autologous serum. Cells were derived from 10 patients with untreated non-Hodgkin's lymphoma (NHL) and from 12 normal individuals. The results were subjected to Analysis of Variance and demonstrated a significant difference between the two groups with respect to erythrophagocytosis but not to rosette formation. In the NHL group, the proportion of erythrophagocytic cells showed no significant increase between the monocyte and macrophage stages (0.07 to 0.09), in contrast to the marked increase seen in the normal group (0.09 to 0.24). In a pilot investigation to examine the possible role of factors in the serum, cells derived from the NHL patients were cultured with serum from healthy donors; they showed no significant difference in the immune-mediated functions from those grown in autologous serum. Overall, the results provide further quantitative evidence of defective macrophage maturation in NHL, presumably reflecting the compromise of host defence mechanisms.


Novel, contrast gradient-oriented, automated chromatin texture analysis. I. Feasibility study on nuclei from benign and malignant breast epithelial cell lines in fine needle aspirates.

Coarse granularity of nuclear chromatin texture is a prominent feature of most malignant cell lines. We have chosen the abrupt transition from eu- to heterochromatic foci (high contrast gradient [CG]) as a novel parameter for coarseness. This feature was quantified using automated image analysis of single nuclei in smears stained by the May-Grünwald-Giemsa technique. The principle of this approach consists of eliminating, with the help of subtraction between two image lowpass filters, the small grey level differences among pixels, so that only high CG values are retained on the digitized image. The sum of these distinctive microareas is then taken as a fraction of the area of the peripherally eroded nucleus, and this ratio is designated as contrast gradient index (CGI) per nucleus. This method was tested on fine needle aspirates from 11 patients with benign breast disease (BBD) and 14 with mammary carcinoma (CA). For each specimen, 60 nuclei were analyzed, with a measuring time per nucleus of about 1 min. A high significant distinction between epithelial cell populations in BBD and CA, respectively, was obtained by variance analysis of all CGIs per nucleus (p = 2 x 10(-18). The median and the mean values of CGI per specimen were the next best discriminators, followed by the modes and the standard deviation of CGI per specimen. The percentage of nuclei per specimen with CGI values of greater than 12 was also significantly greater in CA than in BBD.


Abnormal increase in multinuclear macrophages in primary cultures of BUF/Mna rat thymomas.

The in vitro characteristics of spontaneous thymomas from BUF/Mna rats, a strain with a high incidence of these tumors, were studied. In primary cultures, the adherent cells consisted of mononuclear macrophages, mono- and multi-nuclear epithelial cells and some fibroblastic cells on day 3. The macrophages rapidly increased in number with the formation of large multinuclear cells by day 9. A modest increase in the number and nuclearity of macrophages was also noted in adherent cultures of normal thymuses from 5-week-old BUF/Mna rats. On the other hand, in cultures of thymic cells from 1-year-old or 5-week-old ACI/NMs rats, a normal control rat strain, macrophages did not increase in number and only rarely formed multinuclear cells in adherent cell cultures. These results suggest that abnormal proliferation signal(s) to thymic macrophages and/or their progenitor cells accompanies and may be involved in the development of thymomas in BUF/Mna rats.


Emperipolesis of lymphoid cells by human follicular dendritic cells in vitro.

Isolated follicular dendritic cells (FDCs) showed true and pseudoemperipolesis of fresh tonsillar lymphocytes, even after long-term (50-day) cultivation. Emperipolesis by FDCs was not restricted by allotype specificity, nor was it inhibited by the addition of antibodies against MHC-I & II antigens. Follicular dendritic cells predominantly engulfed B-cells; monocytes and macrophages were not found between FDC cytoplasmic extensions. When highly purified T-cell populations were added to FDC cultures emperipolesis of T-cells occurred, particularly those of the CD4-positive phenotype. Mitoses appeared within 6 h in the emperipolesed lymphocytes and, after an additional 18 h, some lymphocytes exhibited apoptosis.


Blood group antigen expression in medullary carcinoma of the thyroid. An immunohistochemical study on the occurrence of type 1 chain-derived antigens.

Using monoclonal antibodies (MoABs) against blood group determinants and related carbohydrate sequences, it is now possible to clarify their carcinoma-associated modulation at a molecular level. In the present study a panel of MoABs against different type 1 chain derived blood group antigens, comprising A, B, H type 1, Le(a), sialyl-Le(a) (CA 19-9), sialyl type 1 structure (CA 50), and Le(b) was used to investigate their immunoreactivity in 38 medullary carcinomas of the thyroid (MTC) and in normal thyroid tissue. The antigens were not expressed in normal follicular or C-cells but were expressed to a various extent in MTC. The studies revealed some characteristic anomalies in the frequency and patterns of tumor-associated antigen expression. The MoAB C 50 stained 32 of the 38 tumors, H type 1 (Le(d)) was demonstrated in 21 and the Le(b) antigen in 27. The Le(a)- and the A antigen were detected in 10 and 12 tumors and the B antigen in one. From the results some rules about the pathways for tumor-associated re-expression of these antigens can be deduced. Le(a) antigen expression was significantly correlated with the CA 50 and Le(b) antigens. The significant relation observed between A-, H1-, and Le(b) antigen formation in MTC suggests the existence of a carcinoma-associated fucosyltransferase committing the type 1 precursor chain along the H1-antigen pathway, and by further glycosylation to an A-, B-, or a Le(b) antigen. Comparative studies of tumor-associated H type 1 and H type 2 antigen expression revealed that H type 2 antigen synthesis was significantly related to a blood type 0 in the host. On the other hand, H1 antigen reactivity was independent of the AB0 blood type of the hosts and was also detected in H type 2 antigen-negative tumors. These findings support the proposal that even in tumor tissue, H antigen expression is still determined by the interaction of at least two different genes. Despite the occurrence of the precursor substance (CA 50) and the formation of the Le(a)- and Le(b) antigens, indicating the presence of a alpha 1,4-fucosyl-transferase (Lewis-enzyme), only two tumors showed the formation of CA 19-9. In conclusion, the investigations demonstrated the dominant re-expression of three type 1 chain-derived structures in MTC, namely H type 1, Le(b), and CA 50. These findings support the general concept demonstrated in other carcinomas, that fucosyl- and sialyltransferases are preferentially activated in MTC.(ABSTRACT TRUNCATED AT 400 WORDS)


Eosinophilic globule cells in mouse MFH-like sarcomas: lectin histochemistry.

Lectin binding patterns in ten mouse malignant fibrous histiocytoma (MFH)-like sarcomas containing eosinophilic globule (EG) cells and in granular metrial gland (GMG) cells of mouse placenta were stained with nine lectins (Con A, LCA, WGA, DBA, SBA, e-PHA, PNA, RCA-I and UEA-I) by an avidin-biotin-peroxidase-complex method. EG cells stained strongly with DBA, SBA and PNA which are specific for N-acetyl-D-galactosamine and/or D-galactose. DBA and SBA bound throughout the cytoplasm including the globules; PNA reacted preferentially at the cell surface. There was no evidence that these three lectins were reactive for immature EG cells. WGA, RCA-I and e-PHA also gave a slightly to moderately positive reaction to globules of EG cells. The results indicate that the globules contain abundant O-linked sequences of sugars, but also a few N-linked residues. MFH tumor cells showed a variable degree of binding with Con A, RCA-I, and WGA, but did not react with DBA, SBA and PNA. On the other hand, GMG cells exhibited specific affinities for DBA, SBA and PNA with staining patterns similar to those of EG cells. These findings suggest that EG and GMG cells may be of the same cellular lineage.


[Return of circadian blood pressure and heart rate changes in patients with heart transplants].

A loss of the circadian rhythm pattern of blood pressure (BP) and heart rate, as well as the development of hypertension have been found after heart transplantation (Htx). To study whether a return of this rhythm occurs in the long-term after Htx, we used 24-h ambulatory monitoring to study 62 patients 5 days to 6.5 years after Htx. Patients were divided into two groups (Group 1: less than 6 months after Htx (n = 30), Group 2: 6 months or more after Htx (n = 32)). Group 2 had a higher BP and heart rate, as well as a significantly higher difference between systolic day and systolic night BP than group 1. There was also a significantly higher difference in heart rate between day and night values in group 2. The return of the circadian rhythm pattern in the longer term after heart transplantation may result from partial reinnervation of the heart, although other neurohumoral factors or concomitant medication may play a role.


Control of peroxisome proliferation in Saccharomyces cerevisiae by ADR1, SNF1 (CAT1, CCR1) and SNF4 (CAT3).

The Saccharomyces cerevisiae ADR1 gene has recently been demonstrated to control transcription of several genes encoding peroxisomal proteins or proteins necessary for peroxisome formation. Therefore, the effect of two other genes (SNF1 (CAT1, CCR1) and SNF4 (CAT3)) known to control derepression of glucose-repressible genes was studied. Levels of transcripts of genes encoding catalase A, fatty acid beta-oxidation enzymes and of the PAS1 gene are reduced in snf1 and snf4 mutants on ethanol as well as on oleic acid medium. By immunogold labelling with an antibody directed against peroxisomal thiolase, clusters of peroxisomes were detected in wild-type cells, whereas smaller single peroxisomes were observed in adr1 mutant cells. Results of immunofluorescence experiments are consistent with these observations. No peroxisomes were detected in snf1 and snf4 mutants by immunogold labelling as well as by immunofluorescence.


Elimination kinetics of maternally derived thyrotropin receptor-blocking antibodies in a newborn with significant thyrotropin elevation.

To determine the course of maternally derived elevations in thyrotropin-binding inhibitory immunoglobulins in a neonate. Case report. University pediatric endocrinology clinic and endocrine immunology laboratory in Ohio. An infant with elevated thyrotropin levels but near-normal total thyroxine levels, and her mother. None. Thyroid hormone, thyrotropin, and thyrotropin-blocking immunoglobulin concentrations were serially measured in a woman and her infant, who was found to have elevated thyrotropin levels (234 mU/L) and borderline low thyroxine levels (95 nmol/L). As infant thyroxine concentrations remained normal (125 to 145 nmol/L), no thyroxine supplementation was given. Thyrotropin levels decreased concomitantly with thyrotropin-blocking inhibitory immunoglobulin levels, and normalized by day 56 of life. The apparent elimination half-life of thyrotropin-blocking immunoglobulins was 7.5 days. The observed parallel elimination kinetics suggest that the thyrotropin receptor antibody acts as a thyrotropin antagonist, resulting in compensatory thyrotropin elevations. The duration of such elevations may be predicted on the basis of such elimination.


Atrial natriuretic peptide-induced inhibition of aldosterone secretion: a quest for mediator(s)

Atrial natriuretic peptide (ANP) inhibits aldosterone secretion evoked by its physiological secretagogues by a mechanism(s) likely to involve intracellular messengers. When one examines the results of various investigations so far, this premise, although not definitive yet, seems to be supported. Therefore a brief perspective on the cellular messengers of the various secretagogues is provided before the inquiry into the possible mechanism of action of ANP. The receptors of ANP in the adrenal cells have been identified and characterized. ANP inhibits adenylate cyclase in various tissues through an inhibitory G protein, which appears to explain in part the inhibitory effect of ANP on adrenocorticotropin-induced aldosterone secretion. However, there could be other possible effects of ANP as discussed. ANP probably inhibits aldosterone secretion evoked by angiotensin II and potassium by interfering with the appropriate changes in calcium flux and cell calcium concentration, concomitants of stimulation by these secretagogues. The potential modes of these effects are probed. The role of guanosine 3',5'-cyclic monophosphate, which is increased by receptor activation of guanylate cyclase by ANP and is thought to play a major role in the biological effects of ANP in some other tissues, remains controversial in the aldosterone-lowering effect of ANP, and this is also discussed extensively in this review.


Differential collagen and fibronectin production by Thy 1+ and Thy 1- lung fibroblast subpopulations.

Pulmonary fibrosis resulting from diverse etiologies is characterized by proliferation of fibroblasts and excessive accumulation of interstitial collagen. Whether fibrosis is associated with selective expansion of fibroblast subpopulations differing in amounts or types of collagens synthesized is unknown. We have previously isolated lines and clones of normal murine lung fibroblasts based on the presence of the Thy 1 surface antigen. These subpopulations differ in morphology, growth characteristics, and display of class II major histocompatibility complex antigens (R.P. Phipps, D.P. Penney, P. Keng, H. Quill, A. Paxhia, S. Derdak, and M. E. Felch. Am. J. Respir. Cell Mol. Biol. 1: 65-74, 1989). We evaluated the amounts and types of collagen and fibronectin synthesized by Thy 1+ (Fib2-T-3+) and Thy 1- (Fib2-T-4-) lung fibroblast lines and clones. Thy 1+ fibroblast line synthesized two- to threefold more collagen and noncollagen protein than the Thy 1- line. In contrast, both the Thy 1+ and Thy 1- lines synthesized similar amounts of fibronectin. Thy 1+ and Thy 1- lines and clones expressed mRNA for alpha 1(I)-and alpha 1(III)-procollagen and synthesized both types (predominantly type I and lesser amounts of type III) of collagen, protein, and mRNA. The fibroblast clones varied significantly in total collagen and fibronectin production, with one Thy 1- clone (D3) synthesizing the largest amount of collagen but relatively little fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)


Monoaminergic and cholinergic synaptic markers in the nucleus basalis of Meynert (nbM): normal age-related changes and the effect of heart disease and Alzheimer's disease.

Neurotransmitter markers for acetylcholine, serotonin (5-HT), and dopamine (DA) were measured in autopsied human nucleus basalis of Meynert (nbM) from nondemented individuals without heart disease (non-HD) (age range, 4-84 years; n = 77), nondemented individuals with heart disease (HD) (age range, 57-92 years; n = 23), and individuals with Alzheimer's disease (AD) (age range, 59-92 years; n = 22). No significant differences in any chemical marker were found between age-matched HD and non-HD individuals. The activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), and [3H]spiperone binding were regionally distributed within the nbM in control (non-HD) subjects less than 54 years of age. The activity of AChE, 5-[3H]HT binding, and the content of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 5-HT were regionally distributed in the nbM in non-HD, HD, and AD subjects more than 54 years of age. The binding of [3H]spiperone was regionally distributed in the nbM in HD and AD subjects more than 54 years of age, only. Activity of ChAT and AChE, content of 5-HT, 5-HIAA, and DA, binding of 5-[3H]HT, and the turnover number for DA (ratio of HVA/DA) all decreased with increasing age in the non-HD control population. The content of HVA, binding of [3H]spiperone, and the turnover number for 5-HT (ratio of 5-HIAA/5-HT) did not change with increasing age. Significant reductions in ChAT and AChE activities were found in AD nbM compared with postmortem interval- and age-matched HD and non-HD individuals. The reduction of 5-HT and 5-HIAA content and [3H]spiperone binding in individuals with AD of all ages suggests a loss of functional serotonergic innervation of the nbM. Dopaminergic synaptic markers were less affected in AD nbM, although turnover numbers for both DA and 5-HT were increased in AD. Receptor upregulation in response to presynaptic deficits did not occur for DA or 5-HT.


Startle disease, or hyperekplexia: response to clonazepam and assignment of the gene (STHE) to chromosome 5q by linkage analysis.

Familial startle disease (also known as hyperekplexia and congenital "stiff-man" syndrome) is an autosomal dominant disorder characterized by an exaggerated startle reaction of sudden, unexpected auditory or tactile stimuli; affected neonates also have severe and occasionally fatal hypertonia. We recently encountered a large, five-generation family with startle disease, and treated 16 patients (including 1 neonate) with clonazepam; all experienced dramatic and sustained improvement. We performed systematic linkage analysis in this family, and found tight linkage between the disease locus and a polymorphic genetic marker locus (colony-stimulating factor receptor, or CSF1R) that has been physically mapped to chromosome 5q33-q35. The maximum odds ratio favoring linkage over nonlinkage is greater than 10,000,000:1 (lod score, 7.10) at 3% recombination. Several genes encoding neurotransmitter receptor components have been physically mapped to the subtelomeric region of chromosome 5q, and are thus candidates for the startle disease gene. The availability of additional large pedigrees with startle disease should facilitate identification and characterization of the gene for this disorder.


Genetic vulnerability to drug abuse. The D2 dopamine receptor Taq I B1 restriction fragment length polymorphism appears more frequently in polysubstance abusers.

Alcoholics are more likely than nonalcoholics to display the Taq I A1 restriction fragment length polymorphism of the D2 dopamine receptor gene, according to four of six studies that examined alcoholics and controls. The current study examines whether the association observed in alcoholism might extend to other addictive substances by examining D2 dopamine receptor Taq I A and B restriction fragment length polymorphisms in polysubstance users and controls free of significant substance use. We hypothesized a stronger association for the B1 restriction fragment length polymorphism since it lies closer to dopamine receptor protein coding and 5' regulatory regions. Heavy polysubstance users and subjects with DSM-III-R psychoactive substance use diagnoses displayed significantly higher Taq I B1 frequencies than control subjects; Taq I A1 results for these comparisons were less robust. These results are consistent with a role for a D2 dopamine receptor gene variant marked by these restriction fragment length polymorphisms in enhanced substance abuse vulnerability.


Overexpression of erbB-2 protein in gastric adenocarcinoma--a potential role in therapeutic response to adjuvant 5-FU-doxorubicin regimen.

In order to study the influence of erbB-2 protein overexpression on outcome of patients with gastric cancer after attempted curative resection with or without adjuvant chemotherapy, paraffin embedded sections from 109 cases of primary gastric cancer with defined treatments have been immunostained for erbB-2 protein in a retrospective study. Thirty four cases (31%) showed strong membrane staining of tumor cells. erbB-2 overexpression did not show significant effect on outcome when all patients were considered. However, erbB-2 overexpression was an indicator for poor disease free survival (p = 0.0474), local relapse free survival (p = 0.0293), and overall survival (p = 0.0310) of the patients treated with surgery only (N = 51), while it did not show any effect on outcome of patients treated with 5-FU plus Doxorubicin (FA) as adjuvant chemotherapy (N = 58). Furthermore, the apparent therapeutic benefit from FA regimen was restricted to patients with erbB-2 positive tumors. Combined predictive value of erbB-2 and FA regimen was found to be significant in predicting local relapse in multivariate analysis (p = 0.0439). The data suggests that erbB-2 may be associated with an improved response to FA regimen and that erbB-2 should be included as a potential confounding variable in the analysis of the data from the clinical trials for gastric cancer.


Three types of binding by Porphyromonas gingivalis and oral bacteria to fibronectin, buccal epithelial cells and erythrocytes.

This study showed that the interaction of oral bacteria with fibronectin differed with the type of organism examined. Significant binding of fibronectin was found with Porphyromonas gingivalis non-fimbriated (F-) strain in comparison with the fimbriated strain (F+). However, the F+ strain adhered to buccal epithelial cells in significantly larger numbers than the F- strain. Fibronectin binding and epithelial cell adherence were not associated with haemagglutinating activity. These assays clearly define at least three distinct types of binding by oral bacteria: to fibronectin, buccal epithelial cells and erythrocytes.