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S A Brody

Publications and source records attributed to S A Brody.

At least 19 recordsLinked to original sources
PubMed2004

Assessment of a prepulse inhibition deficit in a mutant mouse lacking mGlu5 receptors.

The glutamate hypothesis of schizophrenia derived from evidence that phencyclidine, a noncompetitive N-methyl-D-aspartate (NMDA) antagonist, produces schizophrenia-like symptoms in healthy humans. Sensorimotor gating, measured by prepulse inhibition (PPI), is a fundamental form of information processing that is deficient in schizophrenia patients and rodents treated with NMDA antagonists. Hence, PPI is widely used to study the neurobiology of schizophrenia. As the use of PPI as a model of gating deficits in schizophrenia has become more widespread, it has become increasingly important to assess such deficits accurately. Here we identify a possible role of mGluR5 in PPI by using wild type (WT) and mGluR5 knockout (KO) mice of two different background strains, 129SvPasIco and C57BL/6. In both strains, PPI was disrupted dramatically in the mGluR5 KO mice throughout a range of interstimulus intervals and sensory modalities. The present findings further support the glutamate hypothesis of schizophrenia and identify a functional role for mGluR5 in sensorimotor gating.

Animals↗
PubMed2003

Effect of antipsychotic treatment on the prepulse inhibition deficit of mGluR5 knockout mice.

RATIONALE: Prepulse inhibition of the startle response (PPI), a model of sensorimotor gating, is deficient in persons with schizophrenia. In rodents, the reversal of induced deficits in PPI demonstrates predictive validity for identifying antipsychotic treatments. Metabotropic glutamate receptor 5 (mGluR5) has been implicated in schizophrenia, in part because mGluR5 knockout (KO) mice exhibit PPI deficits. OBJECTIVE: We examined whether mGluR5 KO mice might serve as a novel model for detecting antipsychotic treatments. METHODS: Using C57BL/6J or 129SvPasIco mice, we first determined doses of the typical antipsychotic raclopride or the atypical antipsychotic clozapine that were effective in blocking the PPI-disruptive effects of amphetamine or ketamine, respectively. We then examined the effects of these doses on the deficit in PPI in mGluR5 KO mice. RESULTS: Administration of raclopride or clozapine reversed either an amphetamine or a ketamine-induced PPI deficit, as had the novel mood stabilizer lamotrigine in previous studies. In contrast, the PPI deficit of the mGluR5 KO mice was not altered by administration of raclopride, clozapine, or lamotrigine. The serotonin(2A) antagonist M100,907 was also ineffective in reversing the mGluR5 KO deficit in PPI. CONCLUSIONS: Most of the compounds examined ameliorated at least a subset of pharmacologically induced PPI deficits. That none of the antipsychotic treatments attenuated the PPI deficit in the mGluR5 KO mice indicates that this model is not predictive of known treatments for schizophrenia, but does not preclude a role for the mGluR5 receptor in schizophrenia or other psychiatric disorders.

Animals↗
PubMed2003

Disruption of prepulse inhibition in mice lacking mGluR1.

Sensorimotor gating, measured by prepulse inhibition of the startle response (PPI), is a cross-species form of information processing that is deficient in patients with schizophrenia and is widely used as a model to study the neurobiology of this disorder. The eight known metabotropic glutamate receptors (mGluRs) are divided into three groups on the basis of sequence homology and pharmacological properties. Group I consists of mGluR5 and mGluR1, both of which are coupled positively to phospholipase C. Mice lacking mGluR5 exhibit a deficit in PPI. Like mGluR5, mGluR1 is located in regions that are involved in the modulation of PPI. To test the hypothesis that mGluR1 is involved in the modulation of PPI we assessed PPI in mGluR1 knockout (KO) mice. Littermate mGluR1 wild-type and KO mice were tested at multiple ages in a standard PPI paradigm containing a 65 dB background, 120 dB pulses and prepulses of 69, 73 and 77 dB. At all ages tested, mGluR1 KO mice exhibited a significant PPI deficit. The PPI deficit of the mGluR1 KO mice was not further exaggerated by administration of the N-methyl-d-aspartate antagonist phencyclidine nor was it reversed by administration of the dopamine antagonist raclopride (3.0 mg/kg). The PPI deficit of the mGluR1 KO mice was, however, ameliorated by administration of the mood stabilizer lamotrigine (27 mg/kg base equivalent weight), though increases in PPI were also seen with lamotrigine in the wild-type mice. Thus, both group I metabotropic glutamate receptors are involved in the regulation of PPI in mice.

Acoustic Stimulation↗
PubMed1998

Confirmation of the beneficial effects of brief coincubation of gametes in human in vitro fertilization.

OBJECTIVE: To confirm whether brief exposure of human oocytes to spermatozoa in vitro results in equivalent fertilization rates and possibly better quality embryos than overnight coincubation and to determine if there was a difference in outcome with regard to the type of culture medium used. DESIGN: Prospective distribution of gametes between treatments in sequential patients. SETTING: Assisted reproductive technology program in private hospital. PATIENT(S): Consecutively treated subfertile couples entering an infertility program. INTERVENTION(S): Assisted reproductive technology treatment for infertility involving oocyte retrieval and in vitro fertilization. MAIN OUTCOME MEASURE(S): When possible, the outcome of fertilization and embryo quality were compared when gametes were coincubated for 1 hour or overnight. Two different formulations of human tubal fluid were compared in some cases. RESULT(S): There was no statistically significant difference in fertilization rates between a brief or overnight coincubation of gametes or between the two treatment groups with regard to the type of culture medium used. The quality of the embryos was significantly better in the 1-hour exposure group. The embryos in Basal XI human tubal fluid medium were of significantly better morphological quality than their siblings in D3+ human tubal fluid medium. CONCLUSION(S): Coincubation of oocytes and spermatozoa for a shorter period produced embryos of superior morphological quality than the generally accepted overnight protocol. A simple glucose and phosphate-free human tubal fluid medium resulted in early cleavage embryos of better morphological quality than a medium supplemented with glucose, taurine, and glutathione.

Embryo Transfer↗
PubMed1993

The effects of a long-acting progestin on the hypothalamic-pituitary-ovarian axis in women with normal menstrual cycles.

This study was performed to determine how a long-acting, slow-release preparation of norethindrone (NET) affects the hypothalamic-pituitary-ovarian axis of normal ovulatory women. Ten women were studied during the luteal phase of their menstrual cycle, and again at six and twelve weeks following intramuscular administration of 100 mg NET microencapsulated in poly-D,L-lactide-co-glycolide. Serial LH samples, serum E, P, and NET were followed by a GnRH stimulation test. Compared to luteal phase values, six and twelve weeks of treatment with NET inhibited serum E2 and P while mean serum LH remained unchanged and mean serum FSH increased significantly (p < 0.05). LH pulse frequency after NET treatment was twice the rate (p < 0.01) as that of the luteal phase, whereas LH pulse amplitude was decreased significantly (p < 0.05). Finally, although there was no significant change in pituitary LH secretion in response to GnRH, NET treatment augmented FSH responsiveness to GnRH at the times studied. Preserved pituitary responsiveness to GnRH in NET-treated patients suggests that inhibited ovarian function results in an increase in GnRH pulse frequency but not GnRH pulse amplitude. Since the progestational milieu is maintained in these patients by NET treatment, the decrease in serum E2 may be responsible for the increase in GnRH pulse frequency. The presence of a critical level of E2 may be necessary for progestins to affect the hypothalamic GnRH pulse generator.

Adult↗
PubMed1990

Pharmacokinetics of ethinyl estradiol and mestranol.

Pharmacokinetally, a 50 micrograms oral dose of mestranol (which itself is inactive) is bioequivalent to a 35 micrograms dose of ethinyl estradiol. Physiologically, mestranol ranges from 50% to 100% of the activity of ethinyl estradiol, depending on the endpoint chosen. Compounds such as these, which are metabolized with a first-pass effect and are enterohepatically recirculated, demonstrate large interindividual and intraindividual variability in their pharmacokinetics. Thus a given dose of ethinyl estradiol in one person may produce an effect equivalent to a substantially larger (or smaller) dose in another person. This wide variability confounds efforts to establish tight dose-response relationships, a point rarely considered in clinical or epidemiologic studies of these compounds. The circulating levels of ethinyl estradiol sulfates may be higher than those of free ethinyl estradiol itself. It has been thought that these sulfates represent a "reservoir" of ethinyl estradiol. Our studies show that this idea is untenable because the half-life of the sulfates is not long enough for such an effect. Differences in the pharmacokinetics of ethinyl estradiol and mestranol have been observed in studies of various populations. The reality of these group differences is affirmed by analyses of urinary metabolite patterns.

Biological Availability↗
PubMed1989

Pharmacokinetics of three bioequivalent norethindrone/mestranol-50 micrograms and three norethindrone/ethinyl estradiol-35 micrograms OC formulations: are "low-dose" pills really lower?

We have examined the pharmacokinetic parameters derived from the analysis of plasma ethinyl estradiol (EE) and norethindrone levels after administration of a single dose of three bioequivalent norethindrone-1mg/mestranol (ME)-50 micrograms formulations (Ortho-NovumR 1/50, NorinylR 1/50 and Norcept-MR 1/50) and three norethindrone-1mg/ethinyl estradiol-35 micrograms formulations (Ortho-Novum 1/35R, NorinylR 1/35, Norcept-ER 1/35) in a randomized crossover design involving 24 women for the 35 micrograms and 27 women for the 50 micrograms agents. Differences between the AUC-EE of pairs from the same manufacturer (1 + 35 and 1 + 50) were not significantly different, indicating that 50 micrograms of mestranol was equivalent to 35 micrograms ethinyl estradiol with respect to this pharmacokinetic parameter. The Cmax values were also similar. Inter-individual coefficients of variation (C.V.) for the AUC-EE were 47% and 57% for the 1 + 35 and 1 + 50 agents, respectively. Intra-individual C.V.s were 41% and 42%, respectively. For norethindrone, the AUC was larger with the 1 + 50 formulations than with the 1 + 35 group (87.9 vs. 72.8 pg hr/ml). Additionally, the Cmax values were larger for the 1/50 group (17.7 vs. 14.0). Since the amount of norethindrone in the two dosage groups was the same, this difference in the pharmacokinetics between the 35 micrograms EE and the 50 micrograms ME formulations remains unexplained. The inter-individual C.V. averaged 56% for both dosage groups. The intra-individual C.V.s were 17% and 46% for the 1 + 35 and 1 + 50 groups, respectively. The large variation in blood levels of ethinyl estradiol and norethindrone between and within individuals may overshadow clinical differences attributable to differences in dosage.

Adult↗
PubMed1981

Beneficial effect of hepatitis in leukemic reticuloendotheliosis.

A patient with leukemic reticuloendotheliosis had splenomegaly, neutropenia, and a severe underproduction anemia. During a three-year period, the hematocrit was never in the normal range, and periodic transfusions were required. However, after an episode of hepatitis that was positive for B surface antigen, the spleen became smaller, the number of neutrophils increased, the transfusion requirement disappeared, and the hematocrit rose to normal. Several mechanisms for this observation are proposed.

Hepatitis B↗