Neonatal brain tumor treated by surgery and postoperative radiotherapy.
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Brain Neoplasms↗
Biomedical subjects
S R Weiss
Publications and source records attributed to S R Weiss.
Nontraumatic fistula, cervical portion of vertebral artery-interior jugular vein.
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Angiography↗
Tamoxifen prevents sulpiride-induced weight gain in female rats.
To evaluate its potential utility in counteracting neuroleptic-induced obesity, the effects of long-term administration of tamoxifen (TAM) on body weight (BW) and food intake (FI) of gonadally intact and sulpiride-treated (SUL) female rats were assessed. In addition, estradiol and prolactin serum levels were measured in rats treated with SUL. SUL plus TAM and SUL plus bromocriptine (BR). TAM, at doses of 10, 50 and 100 micrograms, significantly decreased BW gain: FI was significantly reduced at the doses of 50 and 100 micrograms. In addition, doses of TAM ranging from 5-100 micrograms completely prevented SUL-induced BW gain and hyperphagia. BR also prevented SUL effects on BW and FI. In contrast to BR, concomitant administration of TAM did not prevent SUL-induced hyperprolactinemia. Estradiol levels were not modified by SUL alone or SUL plus BR, but they were significantly increased in the animals treated with TAM plus SUL. Neuroleptic-induced obesity in female rats might be related to an alteration in gonadal steroid balance secondary to hyperprolactinemia. While BR might counteract neuroleptic-induced weight gain by preventing hyperprolactinemia, TAM might directly interact with estrogen receptors, or indirectly increase estradiol levels. The use of TAM in preventing neuroleptic-induced obesity in humans warrants further investigation.
Animals↗
The lipid-lowering effects of atorvastatin, a new HMG-CoA reductase inhibitor: results of a randomized, double-masked study.
This randomized, placebo-controlled, double-masked, parallel-group trial assessed the serum cholesterol-lowering effects of atorvastatin, a new 3-hydroxy-3-methylglutaryl coenzyme. A reductase inhibitor, over 26 weeks in patients with primary hypercholesterolemia. Thirty-nine patients from four centers in the United States were originally randomized to one of two treatment groups and received either atorvastatin 10 mg (20 patients) or placebo (19 patients) once daily. Atorvastatin rapidly and significantly reduced serum total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B levels. LDL-C was reduced 35% with atorvastatin 10 mg compared with a 0% increase in LDL-C in the placebo group. Atorvastatin significantly reduced triglyceride levels, with improvements occurring over time. At 26 weeks, triglyceride levels were reduced by 21% with atorvastatin treatment compared with a 14% increase with placebo. The drug was well tolerated and no clinically significant laboratory abnormalities were detected.
Adult↗
Chronic carbamazepine treatment increases brain adenosine receptors.
The effect of carbamazepine on adenosine receptors in vitro has been well documented, with findings from several groups showing that therapeutic doses of this drug are sufficient to inhibit binding to the major portion of adenosine receptors in brain. In this study, we describe the effects of chronic carbamazepine on central adenosine receptors from several areas of rat brain using [3H]diethylphenylxanthine [( 3H]DPX) and [3H]cyclohexyladenosine [( 3H]CHA) as ligands. Carbamazepine was administered to rats orally in the diet at doses of 2.25 g/kg of diet and 5.0 g/kg of diet for periods of 3 and 11 days, respectively. Carbamazepine-treated animals displayed higher levels of adenosine receptors in virtually all brain areas tested, most of which reached significance in the 11-day treatment group. Scatchard analysis revealed increases in the number of receptors. There was no change in peripheral and central type benzodiazepine receptors or beta-adrenergic receptors in the carbamazepine-treated animals. Therefore, carbamazepine treatment in vivo appears to upregulate adenosine receptors, suggesting that this drug may act as an adenosine antagonist.
Animals↗
Upregulation of adenosine A1 receptors and forskolin binding sites following chronic treatment with caffeine or carbamazepine: a quantitative autoradiographic study.
The effects of feeding a diet enriched in caffeine or carbamazepine (CBZ) were investigated in rats in a quantitative autoradiographic study of adenosine A1 receptors (labeled by [3H]cyclohexyladenosine, [3H]CHA) and adenylate cyclase (labeled by [3H]forskolin). Although regional distribution of [3H]CHA and [3H]forskolin binding sites differed in some areas, chronic CBZ as well as chronic caffeine upregulated both of them. The changes in receptor densities occurred in the same brain microregions, suggesting that caffeine and CBZ act as antagonists at similar subpopulations of adenosine A1 receptors and [3H]forskolin binding sites. Therefore, a selective interaction of these two drugs with distinct adenosine A1 receptors (and adenylate cyclase) probably does not explain the differential effects of caffeine and CBZ on neuronal activity.
Adenosine↗
Differential effects of acute and repeated electrically and chemically induced seizures on [3H]Nimodipine and [125I]omega-conotoxin GVIA binding in rat brain.
[3H]Nimodipine and high-affinity [125I]omega-conotoxin GVIA (CgTX) binding were investigated in membranes from rat cerebral cortex, cerebellum, and hippocampus after electrically and chemically induced seizures. Animals were decapitated 30 min after a single electroconvulsive shock (ECS) or lidocaine-induced seizure and 24 h after the last of 10 once-daily ECS or six once-daily lidocaine-induced seizures. After a single ECS, [3H]nimodipine and [125I]CgTX binding sites decreased in cerebral cortex (by 10% and 17%, respectively). A downregulation of [3H]nimodipine binding sites in hippocampus occurred after single and repeated lidocaine-induced seizures (by 24% and 11%, respectively), whereas [125I]CgTX binding remained unaltered. An earlier report on changes in [3H]nitrendipine binding after chronic ECS in cortex and hippocampus was not confirmed.
Animals↗
Development and reversal of contingent inefficacy and tolerance to the anticonvulsant effects of carbamazepine.
The relationship of the timing of drug administration to anticonvulsant efficacy against amygdala kindled seizures was studied. During kindling development, rats received carbamazepine (CBZ, 15mg/kg) before (CBZ-before) or after each amygdala stimulation (CBZ-after). After kindling to full seizures, when all animals were given CBZ before the stimulation, only the CBZ-after group showed a good anticonvulsant response. The rats that had received CBZ before (during development of kindled seizures) remained unresponsive to CBZ treatment (contingent inefficacy). When drug-naive or CBZ-after animals repeatedly received CBZ before electrical stimulation, they developed tolerance to its anticonvulsant effects (contingent tolerance). The tolerance could be reversed by a period of treatment with CBZ-after or by kindling the animal drug-free, but not by CBZ administration alone or by time off from both drug and seizures. These findings suggest that inefficacy and tolerance to CBZ may be affected by the temporal contingencies of drug administration and that responsiveness can be reinstated by altering these contingencies.
Amygdala↗
Corticotropin-releasing hormone: potentiation of cocaine-kindled seizures and lethality.
Carbamazepine (CBZ) blocks the development of local anesthetic seizures kindled by cocaine and lidocaine. Cocaine and lidocaine release corticotropin-releasing hormone (CRH) in hypothalamic cell cultures, and this effect is also blocked by CBZ. Because CRH administered intracerebroventricularly (i.c.v.) can produce seizures, its potential role in the development of cocaine seizures and in the anticonvulsant effects of CBZ was studied. CRH (at doses of 5, 10, and 100 micrograms) potentiated cocaine-kindled seizure development and lethality in a dose-related fashion. CRH also reversed the effects of CBZ on cocaine kindling and lethality, but only at the highest doses, which also affected cocaine kindling. Thus, a selective role for CRH in the anticonvulsant effects of CBZ was not demonstrated. The findings suggest a potentially important role for CRH in exacerbating cocaine-seizure evolution and its associated lethality and confirm the inhibition of cocaine kindling and lethality by CBZ.
Animals↗
Cellular reservoirs for coronavirus infection of the brain in beta2-microglobulin knockout mice.
Mouse hepatitis virus (MHV) A59 infection which causes acute encephalitis, hepatitis, and chronic demyelination, is one of the experimental models for multiple sclerosis. Previous studies showed that lethal infection of beta2-microglobulin 'knockout' (beta2M(-/-)) mice required 500-fold less virus and viral clearance was delayed as compared to infection of immunocompetent C57Bl/6 (B6) mice. To investigate the mechanism of the increased susceptibility of beta2M(-/-) mice to MHV-A59, we studied organ pathology and the distribution of viral antigen and RNA during acute and chronic infection. A59-infected beta2M(-/-) mice were more susceptible to acute encephalitis and hepatitis, but did not have increased susceptibility to demyelination. Viral antigen and RNA distribution in the brain was increased in microglia, lymphocytes, and small vessel endothelial cells while the distribution in neurons and glia was similar in beta2M(-/-) mice and B6 mice. Acute hepatitis and thymus cortical hypoplasia in beta2M(-/-) mice were delayed in onset but pathologic changes in these organs were similar to those in B6 mice. The low rate of demyelination in beta2M(-/-) mice was consistent with the low dose of the virus given. A less neurotropic virus MHV-2, caused increased parenchymal inflammation in beta2M(-/-) mice, but without demyelination. Thus, CD8+ cells were important for viral clearance from endothelial cells, microglia and inflammatory cells, but not from neuronal and glial cells. In addition, CD8+ cells played a role in preventing the spread of encephalitis.
Acute Disease↗
Arteriovenous malformations: follow-up in 68 cases.
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Adolescent↗
Pharmacist's guide to pregnancy registry studies.
OBJECTIVE: To introduce the concept and design characteristics of pregnancy registries and to discuss opportunities for pharmacist involvement. DATA SOURCES: Previous and ongoing pregnancy registry studies that assess the safety of pharmaceutical agents in pregnant women were identified from the medical literature, Internet, abstracts from professional meetings, and personal communications. DATA EXTRACTION: The development and use of the pregnancy registry study for evaluating drug safety is described. Then, to illustrate the application of scientific principles to this unique study design, examples are given from previous and ongoing pregnancy registry studies. DATA SYNTHESIS: Pregnancy registry studies are increasingly used to assess the safety of drugs and other therapeutic agents during pregnancy. In a pregnancy registry, women who took the study drug while pregnant are identified soon after that exposure and followed until their pregnancy ends and its outcome is determined. Information is compiled from hundreds or thousands of pregnancies and used to make a safety assessment. CONCLUSION: Pharmacists can explain pregnancy registries to pregnant women and encourage enrollment. Also, pharmacists can use information derived from these studies to help patients and health care providers manage inadvertent drug exposures and optimize pharmaceutical therapy during pregnancy.
Data Collection↗
Caveats in the use of the kindling model of affective disorders.
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Animals↗