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Biomedical subjects

S G Potkin

Publications and source records attributed to S G Potkin.

At least 91 records · Page 5Linked to original sources

Low CSF 5-hydroxyindoleacetic acid in schizophrenic patients with enlarged cerebral ventricles.

The authors assayed CSF 5-hydroxyindoleacetic acid (5-HIAA) concentrations in 24 chronic schizophrenic patients, 9 of whom had enlarged cerebral ventricles according to computerized tomography scans, and in 15 control subjects with neurological disorders. Although there were no overall differences between the schizophrenic patients and the control subjects, schizophrenic patients with enlarged ventricles had significantly lower 5-HIAA concentrations. Also, ventricular size correlated inversely with 5-HIAA concentrations. The findings are consistent with other evidence that cerebral ventricular size is biologically meaningful in schizophrenic patients.

Adult↗

CSF copper concentrations in chronic schizophrenia.

The authors used a sensitive flameless atomic absorption spectrophotometric procedure to measure CSF copper concentrations in normal controls, former heroin addicts, and unmedicated and medicated chronic schizophrenic patients and found no significant differences in CSF copper levels between these groups. Schizophrenic women had significantly lower CSF copper levels than schizophrenic men, but no significant differences were found between control men and control women. There were no differences in CSF copper levels between patient subgroups with respect to diagnostic subtype (acute versus chronic, paranoid versus chronic undifferentiated), length of hospitalization, race, medication status, platelet monoamine oxidase values, or CAT scan abnormalities.

Adult↗

Measurement of premorbid adjustment in chronic schizophrenia.

The Premorbid Adjustment Scale (PAS) is a rating scale which was developed to be applicable in a research setting. It is designed to evaluate the degree of achievement of developmental goals at each of several periods of a subject's life before the onset of schizophrenia. A description of the scale and its use is presented, along with a discussion of psychometric properties. The PAS has been found to be useful in identifying patients likely to become chronically hospitalized or at high risk for readmission. It may also serve as a possible predictor of patients with brain abnormalities on a computerized tomography (CT) scan.

Adolescent↗

Ex uno multi: subtyping the schizophrenic syndrome.

We studied 93 chronic schizophrenic inpatients, who met the Research Diagnostic Criteria for schizophrenia. Data on a number of historical, epidemiologic, phenomenologic, biochemical, neuropathological, and treatment-response variables were analyzed, using univariate and multivariate statistical analyses. Patients were classified into pairs of subgroups, according to each of the following seven dimensions: (1) ventricle/brain ratio (VBR) assessed on computed tomography scans (normal vs. abnormal); (2) premorbid adjustment (good vs. poor); (3) therapeutic response to neuroleptics (good vs. poor); (4) platelet monoamine oxidase (MAO) activity (low vs. high); (5) paranoid features (present vs. absent); (6) tardive dyskinesia (present vs. absence); and (7) hemispheric asymmetry on computed tomography scans (normal vs. abnormal). These seven dimensions were chosen because earlier studies had shown that the variables involved were operationally definable and were of potential relevance to the subgrouping of schizophrenic patients. Our results suggested that two biological variables, viz., VBR and platelet MAO activity, might be useful in identifying two rather distinct subgroups among chronic schizophrenic patients. A subgroup with large VBR was associated with poor premorbid adjustment, neurological impairment, and poor therapeutic response to neuroleptics, while the subgroup with low platelet MAO activity was characterized by the presence of paranoid features and tardive dyskinesia. Possible explanations, implications, and limitations of our findings are discussed.

Adult↗

Cerebrospinal fluid zinc concentrations in ex-heroin addicts and patients with schizophrenia: some preliminary observations.

Mean CSF zinc concentration was lower in a group of ex-heroin addicts than in groups of normal controls and neuroleptic-treated schizophrenic patients, but values were generally within the normal range of CSF zinc concentrations. There were no significant differences in mean CSF zinc concentrations between groups of drug-free schizophrenic patients, schizophrenic patients on neuroleptics, and normal controls. CSF zinc concentration may be influenced by differences in racial composition and related dietary and other habits of the groups studied.

Adult↗

A probable neuroleptic effect on platelet monoamine oxidase in chronic schizophrenic patients.

Platelet monoamine oxidase activity (MAO) was studied serially over time in 16 chronic schizophrenic patients when medication free and then when medicated. Thirteen of the 16 patients had significant decreases in platelet MAO activity following neuroleptic drug treatment. The change in MAO activity was found to be correlated with response to treatment and to dose of medication.

Adult↗

A biochemical study of tardive dyskinesia in young male patients.

Based on specific criteria, tardive dyskinesia was diagnosed in 6 out of 29 young schizophrenic male inpatients. We compared several biochemical parameters in these six dyskinesia patients with those in six matched controls. The patients with dyskinesia had significantly lower platelet monoamine oxidase activity and significantly higher plasma dopamine-beta-hydroxylase activity as compared with the controls, thus confirming our previous findings in a population of elderly female inpatients. The dyskinetic and nondyskinetic groups did not differ from each other in mean whole blood serotonin concentration and mean serum neuroleptic concentration as measured with a radioreceptor binding assay. Possible significance of our results is discussed.

Adult↗

Cross-cultural study of a biochemical abnormality in paranoid schizophrenia.

We studied 24-hour urinary excretion of phenylethylamine (PEA) and creatinine in 50 schizophrenic (39 paranoid and 11 nonparanoid) and 19 nonpsychiatric patients from Bombay, India. Methods for diagnosis, clinical assessment, and 24-hour urine collection were identical to those used in an earlier study done in a Washington, D.C. hospital. Clinical evaluations were done in Bombay, while urinary PEA and creatinine estimations were performed at NIMH, Washington, without knowledge of the subjects' identify. Paranoid schizophrenic patients had significantly greater 24-hour urinary excretion of PEA than both nonparanoid schizophrenic patients and nonpsychiatric controls. The mean amount of PEA per g creatinine in urine was also highest of paranoid schizophrenic patients. Our findings provide cross-cultural support to the possibility of abnormal PEA metabolism in at least some patients with paranoid schizophrenia.

Adult↗

Wheat gluten challenge in schizophrenic patients.

Eight chronic schizophrenic patients were maintained on a diet free of gluten, cereal grains, and milk (CM-F diet) and challenged in a double-blind manner with dietary wheat gluten and placebo. While on the CM-F diet, each patient received a daily challenge of 30 g of gluten for 5 weeks and a placebo challenge for 8 weeks. No deterioration in clinical status as measured by the BPRS was noted on gluten challenge. Serum alpha 1 acid glycoprotein measurement demonstrated no evidence of inflammatory response to gluten challenge. The data suggest that sensitivity to dietary gluten is not characteristic of young chronic schizophrenic patients.

Adult↗

Lymphocyte monoamine oxidase and plasma prolactin and growth hormone in tardive dyskinesia.

Twelve elderly women with tardive dyskinesia were matched with 12 patients without dyskinesia. Lymphocyte monoamine oxidase (MAO) activity and plasma prolactin and growth hormone concentrations were determined "blind" in these 12 pairs of patients. Chronic schizophrenic patients with tardive dyskinesia had significantly lower lymphocyte MAO activity as compared to controls. Organic brain syndrome patients with dyskinesia did not differ from controls in the lymphocyte MAO activity. These results with lymphocyte MAO parallel our earlier findings on platelet MAO. No significant differences were found between dyskinesia group and controls in the plasma prolactin and growth hormone concentrations. Possible implications of our findings are discussed.

Aged↗

The schizophrenia syndrome. Examples of biological tools for subclassification.

Six biological variables-platelet monoamine oxidase activity, urine phenylethylamine concentration, brain norepinephrine concentration, abnormalities on computerized tomography, lateralization asymmetries, and the presence or absence of tardive dyskinesia-are used to discriminate possible biological groups of schizophrenic patients. All variables successfully subclassify patients, some into divisions consistent with phenomological, psychosocial, or biochemical descriptions or hypotheses of schizophrenia. None of the measures, however, has sufficiently stood the test of time to be of clinical utility.

Amphetamine↗

Monoamine oxidase in schizophrenia: an overview.

A brief history and summary of studies designed to elucidate the role of monoamine oxidase (MAO) in schizophrenia are presented. The majority of these studies have reported a decrease in the platelet enzyme activity of chronic schizophrenic patients when compared to controls. Difficulties encountered when comparing MAO activity measured in different patient populations are also considered. Finally, the significance of decreased platelet MAO activity is discussed with respect to its possible etiological role in some forms of schizophrenia.

Blood Platelets↗

Poor premorbid adjustment and CT scan abnormalities in chronic schizophrenia.

The authors evaluated the premorbid adjustment of 51 chronic schizophrenic patients by retrospective chart analysis using a novel scale. Those patients with CT evidence suggestive of brain atrophy had significantly worse premorbid scores, particularly during childhood, than did the patients with normal scans. This finding provides further support for the clinical relevance of CT findings in chronic schizophrenic patients and implicates a neuropathological process that occurs early in development.

Adult↗