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Biomedical subjects

C Epstein

Publications and source records attributed to C Epstein.

At least 19 recordsLinked to original sources
PubMed2001

Psychological impact of news of genetic risk for Huntington disease.

A one-year longitudinal study was conducted investigating the psychological effects of the news of genetic testing for the Huntington disease (HD) gene. Participants were assessed at baseline (before obtaining news of test results) and at three, six, and 12 months after test results on stress-specific symptom measures. Among carriers of the HD gene, a considerable number (55%) showed evidence of neurological impairment at baseline, indicative of HD. Also noteworthy, these individuals had significantly higher psychological symptom scores at baseline than carriers without neurological impairment or noncarriers. Despite this, these individuals were no more aware of their carrier status at baseline than carriers without HD symptoms or noncarriers. Furthermore, the psychological symptom levels of HD carriers with neurological impairment remained elevated across the follow-up assessments. Results for noncarriers and carriers without HD neurological symptoms were consistent with the findings of previous studies indicating that news of genetic testing for the HD gene had limited detrimental impact. The clinical implications of the results are discussed.

Adaptation, Psychological↗
PubMed2001

Epileptic seizures may begin hours in advance of clinical onset: a report of five patients.

Mechanisms underlying seizure generation are traditionally thought to act over seconds to minutes before clinical seizure onset. We analyzed continuous 3- to 14-day intracranial EEG recordings from five patients with mesial temporal lobe epilepsy obtained during evaluation for epilepsy surgery. We found localized quantitative EEG changes identifying prolonged bursts of complex epileptiform discharges that became more prevalent 7 hr before seizures and highly localized subclinical seizure-like activity that became more frequent 2 hr prior to seizure onset. Accumulated energy increased in the 50 min before seizure onset, compared to baseline. These observations, from a small number of patients, suggest that epileptic seizures may begin as a cascade of electrophysiological events that evolve over hours and that quantitative measures of preseizure electrical activity could possibly be used to predict seizures far in advance of clinical onset.

Action Potentials↗
PubMed1999

CuZn superoxide dismutase transgenic retinal transplants.

BACKGROUND: The morphology of retinal transplants is believed to depend on the extent of mechanical disruption of the donor tissue during the surgical procedure and on local factors of the host environment. We hypothesized that oxidative stress during donor tissue preparation and implantation further affects transplant development and investigated the effects of CuZn superoxide dismutase (SOD) overexpression on the survival and morphological development of mouse embryonic retinal transplants. METHODS: Retinae and livers from embryonic day 14-15 SOD overexpressing transgenic mice and CBA control mice were harvested under sterile conditions. In order to identify transgenic mouse embryos, the embryonic livers were analyzed via nondenaturing gel-electrophoresis for the presence of the human SOD protein. Neural retinae were transplanted as fragmented tissue into the subretinal space of albino BALB/c mice. At 4-8 weeks following transplantation, the grafted eyes were fixed in Bouin's solution and processed for histological analysis. RESULTS: Both SOD transgenic and control retinal transplants had developed all retinal layers except for a ganglion cell layer and exhibited a similar extent of rosette formation. Computer-assisted, quantitative assessment of retinal graft volumes revealed a significant, around 58% increase in size of SOD transgenic transplants compared with controls. CONCLUSIONS: Enhanced intracellular SOD levels do not seem to influence retinal transplant morphology as detected by light microscopy. However, volumes of the SOD transgenic transplants were found to be increased compared to control grafts.

Animals↗
PubMed1998

Altered surfactant homeostasis and alveolar type II cell morphology in mice lacking surfactant protein D.

Surfactant protein D (SP-D) is one of two collectins found in the pulmonary alveolus. On the basis of homology with other collectins, potential functions for SP-D include roles in innate immunity and surfactant metabolism. The SP-D gene was disrupted in embryonic stem cells by homologous recombination to generate mice deficient in SP-D. Mice heterozygous for the mutant SP-D allele had SP-D concentrations that were approximately 50% wild type but no other obvious phenotypic abnormality. Mice totally deficient in SP-D were healthy to 7 months but had a progressive accumulation of surfactant lipids, SP-A, and SP-B in the alveolar space. By 8 weeks the alveolar phospholipid pool was 8-fold higher than wild-type littermates. There was also a 10-fold accumulation of alveolar macrophages in the null mice, and many macrophages were both multinucleated and foamy in appearance. Type II cells in the null mice were hyperplastic and contained giant lamellar bodies. These alterations in surfactant homeostasis were not associated with detectable changes in surfactant surface activity, postnatal respiratory function, or survival. The findings in the SP-D-deficient mice suggest a role for SP-D in surfactant homeostasis.

Animals↗
PubMed1998

The use of rapid-rate transcranial magnetic stimulation (rTMS) in refractory depressed patients.

Rapid-rate transcranial magnetic stimulation (rTMS) allows for the noninvasive examination of the cerebral cortex. Recent studies have begun to investigate whether rTMS may be therapeutic for the treatment of depression. In the present study, the authors report on the safety and efficacy of rTMS in treating 50 patients with refractory depression. Overall, there were 21 responders (42%). Interestingly, 56% of the young patients responded, but only 23% of the elderly patients responded to rTMS. Overall, rTMS was well tolerated in all patients. Specifically, no patient developed a new onset of seizures during rTMS. The authors discuss the extant literature on rTMS for the treatment of depression along with future areas of research.

Aged↗
PubMed1997

Impairments of brain and behavior: the neurological effects of alcohol.

Chronic heavy drinking and alcoholism can have serious repercussions for the functioning of the entire nervous system, particularly the brain. These effects include changes in emotions and personality as well as impaired perception, learning, and memory. Neuropathological and imaging techniques have provided evidence of physical brain abnormalities in alcoholics, such as atrophy of nerve cells and brain shrinkage. At the cellular level, alcohol appears to directly affect brain function in a variety of ways, primarily by interfering with the action of glutamate, gamma-aminobutyric acid, and other neurotransmitters. Neurological disorders also can result from vitamin deficiency and liver disease, two health problems that commonly occur with alcoholism. Other hypotheses, based on factors such as aging, gender, and genetics, have been developed to explain various alcohol-related neurological consequences. Many pharmacological treatments to improve neuropsychological functioning in alcoholics have been tested, but none has proved entirely successful. With prolonged abstinence, however, slow recovery of cognitive functioning can occur in some cases.

Alcohol Drinking↗
PubMed1996

Autoradiographic evidence for methamphetamine-induced striatal dopaminergic loss in mouse brain: attenuation in CuZn-superoxide dismutase transgenic mice.

Methamphetamine (METH) has long-lasting neurotoxic effects on the nigrostriatal dopamine (DA) system of rodents. METH-induced neurotoxicity is thought to involve release of DA in presynaptic DA terminals, which is associated with increased formation of oxygen-based free radicals. We have recently shown that METH-induced striatal DA depletion is attenuated in transgenic (Tg) mice that express the human CuZn-superoxide dismutase (SOD) enzyme. That study did not specifically address the issue of loss of DA terminals. In the present study, we have used receptor autoradiographic studies of [(125)I]RTI-121-labeled DA uptake sites to evaluate the effects of several doses of METH on striatal DA terminals of Non-Tg as well as of heterozygous and homozygous SOD-Tg mice. In Non-Tg mice, METH caused decreases in striatal DA uptake sites in a dose-dependent fashion. The loss of DA terminals was more prominent in the lateral region than in the medial subdivisions of the striatum. In SOD-Tg mice, the loss of DA terminals caused by METH was attenuated in a gene dosage-dependent fashion, with the homozygous mice showing the greatest protection. Female mice were somewhat more resistant than male mice against these deleterious effects of METH. These results provide further evidence for a role of superoxide radicals in the long-term effects of METH. They also suggest the notion of a gender-specific handling of oxidative stress.

Animals↗
PubMed1996

AP-1 DNA-binding activation by methamphetamine involves oxidative stress.

Methamphetamine (METH) caused dose-dependent increases in AP-1 DNA-binding activity in both nontransgenic (Non-Tg) and CuZn-SOD transgenic (SOD-Tg) mice. However, the increases in SOD-Tg mice were less prominent than those observed in Non-Tg animals. The time-course of METH-induced AP-1 changes was similar in both strains of mice. AP-1 binding activity showed an initial increase at 1 h, peaked at 3 h, and then gradually declined. AP-1 binding activity was back to normal by the 72-h time point. Regional analyses of METH effects revealed increases in the caudate putamen and cerebellum, with the striatum showing relatively higher METH-induced AP-1 DNA-binding activation. These regional effects were also attenuated in the SOD-Tg mice. These data indicate that METH-induced stimulation of AP-1 DNA-binding depends on cellular redox status. These results are consistent with in vitro studies that have reported that several transcription factors are regulated through redox mechanisms.

Animals↗
PubMed1995

Methamphetamine-induced serotonin neurotoxicity is mediated by superoxide radicals.

Methamphetamine (METH) causes deleterious effects in brain monoaminergic systems. Evidence has accumulated to suggest that these effects may be mediated via the overproduction of the superoxide radicals. We have recently shown that METH-induced dopamine (DA) depletion is attenuated in copper-zinc superoxide dismutase (CuZnSOD) transgenic (Tg) mice. In the present study, we have used receptor autoradiographic studies of [125I]RTI-55 labeled serotonin (5-HT) uptake sites to evaluate the effect of a two dosing schedule (5 mg/kg or 10 mg/kg x 4) of METH on striatal 5-HT uptake sites in nontransgenic (Non-Tg), heterozygous (Hetero) and homozygous (Homo) SOD-Tg mice. The low dose caused no significant changes in striatal 5-HT uptake sites in any of the groups. The high dose caused marked decreases (-74%) in striatal 5-HT uptake sites in Non-Tg mice. In contrast, 5-HT uptake sites showed only a 31% decrease in homozygous SOD-Tg mice whereas heterozygous SOD-Tg mice showed 63% depletion. These results show that increased SOD activity can protect against METH-induced neurotoxicity in striatal serotonergic terminals. These data provide further evidence for a role of oxidative stress in the neurotoxic effects of METH.

Animals↗
PubMed1995

Superoxide radicals mediate the biochemical effects of methylenedioxymethamphetamine (MDMA): evidence from using CuZn-superoxide dismutase transgenic mice.

The subacute and long-term biochemical effects of methylenedioxymethamphetamine (MDMA) were assessed in homozygous and heterozygous transgenic (Tg) mice that carry the complete sequence of the human copper-zinc (CuZn) superoxide dismutase (SOD) gene. Non-transgenic (Non-Tg) mice showed significant decreased in striatal dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) levels both at 24 h and at 2 weeks after a single injection of MDMA (50 mg/kg). Heterozygous SOD-Tg mice showed DA depletion only at the 24 h time point. In contrast, homozygous SOD-Tg mice show no DA or DOPAC depletion at either the 24 h or at the 2 week time points. Moreover, three injections of MDMA (50 mg/kg) given 24 h apart also caused marked reduction of striatal DA and DOPAC in Non-Tg mice when these substances were measured 2 weeks after the last MDMA injection. That injection schedule also caused small decreases in DA levels in the heterozygous animals but no changes in the homozygous mice; DOPAC levels were not affected in the heterozygous nor in the homozygous SOD-Tg mice. Furthermore, the multiple injection schedule caused significant decreases in DA and DOPAC in female Non-Tg mice but not in the two strains of transgenic mice. Neither the single dose nor the multiple dose schedule of MDMA injections affected striatal serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in any of the three strains of mice. These results support previous observations that MDMA-induced biochemical effects are observed in the DA systems of mice, whereas these effects are seen in the 5-HT systems of rats. The present observations also document for the first time a role for the production of superoxide radicals in these effects of MDMA. These mice are an important tool for dissecting pathways involved in drug-induced neurotoxicity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

CuZn-superoxide dismutase (CuZnSOD) transgenic mice show resistance to the lethal effects of methylenedioxyamphetamine (MDA) and of methylenedioxymethamphetamine (MDMA).

We have used female and male transgenic (Tg) mice that carry the complete sequence of the human copper-zinc (CuZn) superoxide dismutase (SOD) gene in order to assess the lethal effects of methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA). In contrast to non-Tg mice, both heterozygous and homozygous SOD-Tg mice showed resistance to the lethal effects of both drugs. Females of both SOD-Tg and non-Tg strains were somewhat more resistant to the effects of these drugs in comparison to males. In general, homozygous animals show greater resistance to the effects of the two drugs. These results suggest that the acute lethal effects of amphetamine-substituted analogs might involve the intracellular overproduction of the superoxide radicals secondary to hypoxic injury. The gender differences suggest that there might be hormonal-free radical scavenger interactions that offer better protection to female mice. This might be related both to the lifespan of and to the lower prevalence of Parkinson's disease in women. Future studies will need to address these issues further.

3,4-Methylenedioxyamphetamine↗
PubMed1994

Use of the immunotoxin N901-blocked ricin in patients with small-cell lung cancer.

In patients with small-cell lung cancer (SCLC), relapse with resistant disease often causes death. N901-blocked ricin (N901-bR), a murine monoclonal antibody (MAb)-blocked ricin immunotoxin, is a potential therapeutic for SCLC. N901-bR targets CD56, present on SCLC and cells of neuro-ectodermal origin. N901-bR kills up to 5 logs of CD56-positive cells at a concentration of 0.25 nM, while CD56-negative cells require 1000-fold more drug to achieve similar cell kill. We treated 21 patients with relapsed or refractory SCLC with a single 7-day course of N901-bR as a continuous infusion. We determined the MTD and toxicity profile, demonstrated drug binding to tumor cells in biopsies of lung, liver and bone marrow, and determined the time to development of human anti-mouse and anti-ricin antibodies. One patient had a documented PR and 6 patients demonstrated stable disease. Toxicity included transient elevation of liver enzymes, mild thrombocytopenia, hypoalbuminemia, fever, malaise, and evidence of capillary leak syndrome. Toxicities were controllable and reversible. No apparent drug-related central- or peripheral-nervous-system toxicity was noted by serial neurologic examinations, EMGs, and nerve conduction studies. Trials of N901-bR are planned in SCLC patients achieving CR and PR following chemoradiotherapy, and in relapsed/refractory patients. Anti-B4-bR will be added as an immunosuppressant in order to permit delivery of multiple courses of N901-bR. Additional trials will investigate synergy with conventional chemotherapeutics and the use of N901-bR as a sensitizing agent for chemotherapy-resistant tumors.

Animals↗
PubMed1994

Attenuation of methamphetamine-induced neurotoxicity in copper/zinc superoxide dismutase transgenic mice.

Administration of methamphetamine (METH) to rats and nonhuman primates causes loss of terminals in the nigrostriatal dopaminergic system. The mechanism by which METH causes its neurotoxicity is not known. To evaluate further the role of oxyradicals in METH-induced neurotoxicity, we have tested its effects in CuZn superoxide dismutase (SOD) transgenic (Tg) mice, which express the human CuZnSOD gene. In non-Tg mice, acute METH administration causes significant decreases in levels of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the striata and cortices of non-Tg mice. In contrast, there were no significant decreases in cortical or striatal DA in the SOD-Tg mice. The effects of METH on DOPAC were also attenuated in both structures of these SOD-Tg mice. Chronic METH administration caused decreases in levels of striatal DA and DOPAC in the non-Tg mice, whereas the SOD-Tg mice were not affected. These results suggest that METH-induced dopaminergic toxicity in mice may be secondary to increased production of reactive oxygen species such as the superoxide radical.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Phase I/II trial of recombinant human granulocyte-macrophage colony-stimulating factor following allogeneic bone marrow transplantation.

Forty-seven patients with hematologic neoplasia received recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) by daily 2-hour infusion following allogeneic bone marrow transplantation from HLA-identical sibling donors in a phase I-II dose-escalation trial. Dose levels ranged from 30 to 500 micrograms/m2/d. At doses at or below 250 micrograms/m2/d, toxicity felt to be caused by rhGM-CSF was negligible. However, three of five patients treated with 500 micrograms/m2/d had unacceptable side effects caused by rhGM-CSF. Two different graft-versus-host disease (GVHD) prophylactic regimens were administered. Twenty-seven evaluable patients were administered regimens that did not contain methotrexate (MTX) (Group I) and reached an absolute neutrophil count of 1,000/microL by a median of day 14. In contrast, 18 patients who received GVHD prophylactic regimens containing MTX (Group II) reached an absolute neutrophil count of 1,000/microL on a median of day 20. Patients in Group I had fewer febrile days and, of those discharged, had shorter initial hospitalizations than patients in Group II. The overall incidence of severe acute GVHD (grade 2 or greater) in the rhGM-CSF-treated patients was 28% and was similar to that in historical "good risk" patients who did not receive rhGM-CSF. These preliminary data suggest rhGM-CSF is unlikely to exacerbate GVHD in HLA-identical sibling donor transplants and indicate the need for randomized trials of rhGM-CSF in allogeneic marrow transplant patients.

Adolescent↗
PubMed1991

GM-CSF as an alternative to dose modification of the combination zidovudine and interferon-alpha in the treatment of AIDS-associated Kaposi's sarcoma.

Combined zidovudine (ZDV) and interferon-alpha (IFN) is an appealing therapy for AIDS-associated Kaposi's sarcoma because of the antiretroviral as well as antitumor potential of this combination. Overlapping myelotoxicity of these agents, however, frequently complicates their clinical use. This phase I/II study was undertaken to test the safety and efficacy of granulocyte-macrophage colony stimulating factor (GM-CSF) in those patients who became neutropenic while receiving ZDV (1,200 mg/day) and IFN (9 MU/day). Despite a "high-risk" population of patients, the tumor response rate among evaluable patients was 50% (33% overall). Sixty-four percent of patients required GM-CSF and all patients receiving GM-CSF had a prompt improvement in their absolute neutrophil count (ANC). The use of GM-CSF was associated with an improved end of study ANC (p less than 0.05), but was not associated with tumor response, CD4 count improvement, or improved change in hemoglobin concentration. GM-CSF/ZDV/IFN was not associated with increased toxicity over ZDV/IFN; however, two unusual events occurred in the GM-CSF/ZDV/IFN group: erythema multiforme and glucose intolerance. Dose-limiting thrombocytopenia and anemia were seen in two patients and anemia in one patient on GM-CSF/ZDV/IFN. No consistent alterations in serum HIV p24 antigenemia were noted in either group. The use of GM-CSF mitigated the neutropenia of combined ZDV and IFN. Further study evaluating the utility of this hematopoietic growth factor in combination therapies for AIDS patients is warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Granulocyte-macrophage colony-stimulating factor mitigates the neutropenia of combined interferon alfa and zidovudine treatment of acquired immune deficiency syndrome-associated Kaposi's sarcoma.

The combined use of zidovudine (ZDV) and interferon (IFN) alfa-2a has been shown to have antiretroviral and antitumor potential benefit in the treatment of acquired immune deficiency syndrome (AIDS)-associated Kaposi's sarcoma (KS). However, the clinical use of this combination is frequently complicated by the overlapping myelotoxicity of these agents. We report here the results of a phase I/II study in which granulocyte-macrophage colony-stimulating factor (GM-CSF) was used for those KS patients who became neutropenic while receiving ZDV (1,200 mg/d) and IFN (9 x 10(6) U/d). Nineteen of 29 patients (66%) developed an absolute neutrophil count (ANC) of less than 1,000 cells per cubic millimeter and were begun on GM-CSF. All experienced a prompt increase in the ANC. Those patients receiving GM-CSF/ZDV/IFN alfa-2a had an improved end of study ANC when compared with the ZDV/IFN alfa-2a group, but did not have an increased rate of tumor response, end of study CD4 cell count, or improvement in any other hematologic variable. The use of GM-CSF was not associated with increased toxicity and, in particular, was not associated with a change in serum human immunodeficiency virus (HIV) p24 antigen. Tumor response was noted in 50% of the assessable patients (33% overall) despite "high-risk" characteristics in 80%. Of the responding patients, seven were on GM-CSF and might have otherwise required an alteration in ZDV/IFN alfa-2a dose level. Further study of GM-CSF as an alternate to dose modification of this (ZDV/IFN alfa-2a) and other combination therapies for AIDS patients is warranted.

Acquired Immunodeficiency Syndrome↗