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Biomedical subjects

S G Potkin

Publications and source records attributed to S G Potkin.

At least 73 records · Page 4Linked to original sources
PubMed1990

Patterns of neuroleptic usage in continuously hospitalized chronic schizophrenic patients: evidence for development of drug tolerance.

A retrospective review of neuroleptic dosages over a five-year period in 19 chronic schizophrenic patients revealed that the majority (85 percent) had either consistent yearly increases or decreases in dosage, although clinical status remained unchanged. The authors present differences in adverse effects between the two groups and discuss the implications of their findings for the concepts of neuroleptic drug tolerance and supersensitivity psychosis.

Adult↗
PubMed1989

EEG alpha photic driving abnormalities in chronic schizophrenia.

Periodic photic stimuli across the entire electroencephalographic (EEG) frequency range were used in an attempt to assess EEG functional differences between chronic schizophrenic patients and control subjects. The EEG responses to these photic stimuli were significantly attenuated in the schizophrenic patients, specifically at the frequencies within the EEG alpha range. The schizophrenic patients also showed an alpha range attenuation in the "no stimulus" EEG alpha measure, such that there was a significant correlation across subjects between the "stimulus" and "no stimulus" EEG alpha range abnormalities. These abnormalities are discussed with reference to possible dysfunctional thalamic mechanisms involved in the pacing of EEG alpha activity and the gating of information through the cerebral cortex.

Adult↗
PubMed1989

Limited eye movement patterns in chronic schizophrenic patients.

Eye movements of 29 chronic schizophrenic patients and 23 normal control subjects were measured by an eye mark recorder during viewing of stationary geometric figures. The results suggested that the eye movements of schizophrenic patients were more limited than those of normal control subjects and that the abnormal eye movement inspection patterns in schizophrenic patients may reflect a lack of visual investigation of novel stimuli in the environment. Our findings, together with Moriya's (1979) observation of similar eye movement pattern abnormalities in the relatives of schizophrenic patients, support the hypothesis that the limited eye movement patterns may be a biological marker for schizophrenia.

Adult↗
PubMed1988

Depression associated with nifedipine-induced calcium channel blockade.

Four cases are reported in which substantial depression was associated with the use of the calcium channel blocker nifedipine. In one instance, a patient became unresponsive to treatment with nortriptyline when nifedipine was introduced. In each case, the depression resolved following discontinuation of nifedipine. Possible mechanisms by which nifedipine may influence affective states are discussed.

Aged↗
PubMed1988

S-adenosylmethionine treatment of depression: a controlled clinical trial.

The antidepressant properties of S-adenosylmethionine, an endogenous methyl donor, were studied in inpatients who met the DSM-III criteria for major depression. Nine patients given intravenous S-adenosylmethionine and nine given low oral doses of imipramine were compared in a double-blind design for 14 days. The S-adenosylmethionine produced superior results by the end of the first week of treatment. By the end of the second week, 66% of the S-adenosylmethionine patients had a clinically significant improvement in depressive symptoms, compared to 22% of the imipramine patients. Side effects appeared to be fewer with S-adenosylmethionine than with imipramine during the last 5 days of the study.

Administration, Oral↗
PubMed1988

Neuroleptic plasma concentrations and clinical response: in search of a therapeutic window.

There is much interest in finding a therapeutic window for commonly used neuroleptics so that dosage can be individualized and side effects minimized. The authors review specific requirements of good study design and survey the literature that has investigated the relationship between therapeutic response and plasma concentrations of neuroleptics. The evidence from a number of fixed-dose haloperidol studies suggests, but does not yet prove, the existence of a therapeutic window for this compound.

Antipsychotic Agents↗
PubMed1984

Haloperidol concentrations elevated in Chinese patients.

After 6 weeks of fixed dose oral haloperidol treatment. Chinese schizophrenic patients (in the People's Republic of China) had 52% higher plasma haloperidol concentrations than U.S. non-Asian schizophrenic patients. Chinese and U.S. patients were matched for sex and body weight. The difference in plasma drug concentrations may explain why Asians are reported to require smaller dosages of neuroleptic drugs than non-Asians, and why they may be more sensitive to neuroleptic-induced side effects. When prescribing haloperidol to persons of Asian ancestry, physicians should consider that higher than expected plasma haloperidol concentrations and an increased sensitivity to haloperidol may occur.

Adult↗
PubMed1984

Schizophrenic outcome in late life: symptom state and platelet monoamine oxidase activity.

Reported here are the results of a study of symptom state, platelet monoamine oxidase (MAO) activity, and demographic variables in a group of elderly neuroleptic-free schizophrenics. Analyzed by both bivariate and multivariate techniques, the data from this sample indicate that after the effects of demographic variables upon the variance of enzyme activity have been controlled for, the patients most likely to continue to manifest schizophrenic symptomatology in the senium are those with low platelet MAO activity. The results are discussed with respect to other studies of platelet MAO and prognosis in schizophrenia and with respect to future studies.

Aged↗
PubMed1984

Amelioration of psychosis with carbidopa. A case report.

We have recently demonstrated that some patients with atypical bipolar affective disorders, characterized by psychotic manias and depressions, have fluctuating and episodic high urinary phenylethlamine (PEA) excretion. We treated a 30 year old woman, who has this disorder, with 200 mg/24 hours of carbidopa. Her psychosis was ameliorated and the urinary PEA output stabilized to a low normal level. Upon withdrawal of carbidopa her psychosis worsened and improved again when carbidopa treatment was reinstated. Carbidopa did not affect the duration or severity of the patient's mood cycles.

Adult↗
PubMed1983

Plasma phenylalanine, tyrosine, and tryptophan in schizophrenia.

Plasma phenylalanine, tyrosine, and tryptophan concentrations were measured in chronic schizophrenic patients, normal controls, and heterozygotes for phenylketonuria. Schizophrenic patients' plasma concentrations of these amino acids could not be distinguished from those of normal controls, either when fasting or following oral or intravenous (IV) phenylalanine challenge. No neuroleptic effect was observed. Plasma phenylalanine-tyrosine ratios following IV phenylalanine challenge could easily distinguish heterozygotes from schizophrenic and normal control subjects but could not distinguish schizophrenic subjects from normal control subjects. No overlap between heterozygotes' values and those of the schizophrenic and normal subjects was observed. These studies find no evidence of abnormal phenylalanine metabolism in schizophrenic persons. Phenylalanine challenge did not affect the abstraction or judgment capacities of the subjects.

Administration, Oral↗