Biomedical subjects

Thomas B Cooper

Publications and source records attributed to Thomas B Cooper.

48 records · Page 3Linked to original sources

PubMed2003

Serum antimuscarinic activity during clozapine treatment.

This study attempts: (1) to verify that serum antimuscarinic activity is related to clozapine dose, and more importantly to clozapine plasma concentrations; (2) to explore whether norclozapine has serum antimuscarinic activity; (3) to explore whether antimuscarinic activity is related to clozapine side effects; and (4) to compare the serum antimuscarinic activities of clozapine with those of antiparkinsonian drugs and other antipsychotics. In 39 patients participating in a double-blind clozapine study, the [3H]QNB assay was used to measure serum antimuscarinic activity: (1) on baseline medications; (2) after a 4-week haloperidol trial; (3) after a 16-week clozapine trial of either 100, 300, or 600 mg/d; and (4) after 1 or 2 consecutive 16-week clozapine trials with remaining doses in nonresponders. Clozapine levels predicted serum antimuscarinic activity better than clozapine dose. At the end of the 1st clozapine trial, the correlation with the levels explained 69% of the variance of serum antimuscarinic activity (r = 0.83, P < 0.001, N = 34). Clozapine levels were good predictors of serum antimuscarinic activity only in patients taking 300 or 600 mg/d. After correcting for clozapine levels, the within-subject correlation between norclozapine levels and serum antimuscarinic activity was relatively high and significant (r = 0.54, F = 26.7, df = 1.65, P < 0.001). Constipation was significantly associated with higher serum antimuscarinic activity during the 1st clozapine trial. Clozapine was associated with clearly higher antimuscarinic activity than other antipsychotics or low doses of antiparkinsonians. In vitro studies and new clinical studies are needed to verify whether norclozapine may significantly contribute to antimuscarinic activity during clozapine treatment.

Antipsychotic Agents↗

PubMed2003

Changes in glucose and cholesterol levels in patients with schizophrenia treated with typical or atypical antipsychotics.

OBJECTIVE: The association of hyperglycemia and hypercholesterolemia with use of atypical antipsychotics has been documented in case reports and uncontrolled studies. The authors' goal was to assess the effects of clozapine, olanzapine, risperidone, and haloperidol on glucose and cholesterol levels in hospitalized patients with schizophrenia or schizoaffective disorder during a randomized double-blind 14-week trial. METHOD: One hundred fifty-seven patients with schizophrenia or schizoaffective disorder who were inpatients at four hospitals were originally included in the study. The 14-week trial consisted of an 8-week fixed-dose period and a 6-week variable-dose period. Planned assessments included fasting glucose and cholesterol, which were collected at baseline and at the end of the 8-week period and the following 6-week period. RESULTS: One hundred eight of the 157 patients provided blood samples at baseline and at least at one point after random assignment to clozapine, olanzapine, risperidone, or haloperidol during the treatment trial. Seven of these patients had diabetes; their glucose levels were >125 mg/dl at baseline. Data from 101 patients were used for statistical analyses. During the initial 8-week period there was an overall significant increase in mean glucose levels. There were significant increases in glucose levels at the end of the 8-week fixed-dose period for patients given clozapine (N=27) and those given haloperidol (N=25). The olanzapine group showed a significant increase of glucose levels at the end of the 6-week variable-dose period (N=22). Fourteen of the 101 patients developed abnormal glucose levels (>125 mg/dl) during the trial (six with clozapine, four with olanzapine, three with risperidone, and one with haloperidol). Cholesterol levels were increased at the end of the 8-week fixed-dose period for the patients given clozapine (N=27) and those given olanzapine (N=26); cholesterol levels were also increased at the end of the 6-week variable-dose period for patients given olanzapine (N=22). CONCLUSIONS: In this prospective randomized trial, clozapine, olanzapine, and haloperidol were associated with an increase of plasma glucose level, and clozapine and olanzapine were associated with an increase in cholesterol levels. The mean changes in glucose and cholesterol levels remained within clinically normal ranges, but approximately 14% of the patients developed abnormally high glucose levels during the course of their participation in the study.

Adult↗

PubMed2003

Cigarette smoking, suicidal behavior, and serotonin function in major psychiatric disorders.

OBJECTIVE: Cigarette smoking is associated with a higher risk for suicide and attempted suicide, but psychopathological or biological explanations for this association have not been explored. Lower serotonin function and impulsive/aggressive traits are associated with suicidal acts, including completed suicide. The authors hypothesized that the relationship that may exist between cigarette smoking and suicidal behavior may be associated with lower serotonin function and the presence of impulsive/aggressive traits. METHOD: Study subjects were 347 patients with a psychiatric disorder (175 with depression, 127 with schizophrenia, and 45 with other disorders). Fifty-three percent of the subjects (N=184) had a lifetime history of suicide attempt, and 47% (N=163) had never attempted suicide. Smoking behavior, lifetime suicidal behavior, and psychopathology were assessed. Serotonin function was assessed in a subgroup of patients with depression (N=162) by using a fenfluramine challenge test and/or measurement of CSF levels of 5-hydroxyindoleacetic acid. RESULTS: Among all patients, smokers were more likely to have made a suicide attempt (adjusted odds ratio=2.60, 95% confidence interval=1.60-4.23) and had higher suicidal ideation and lifetime aggression scores, compared with nonsmokers. An inverse relationship was observed between amount of cigarette smoking and both indices of serotonin function. CONCLUSIONS: The association between cigarette smoking and the presence and severity of suicidal behavior across major psychiatric disorders may be related to lower brain serotonin function in smokers with depression. Further investigation is required to replicate these findings, to measure serotonin function in patients with disorders other than depression, and to test potential therapeutic effects of serotonin-enhancing treatments on both smoking behavior and suicide risk.

Adolescent↗

PubMed2002

Neurocognitive correlates of the COMT Val(158)Met polymorphism in chronic schizophrenia.

BACKGROUND: Neurocognitive deficits are recognized as a cardinal feature of schizophrenia, but the determinants of these deficits remain unknown. Recent reports have suggested that a functional polymorphism, Val(158)Met in exon III of the catechol-O-methyltransferase gene, shares approximately 4% variance with performance on the Wisconsin Card Sorting Test. These findings led to suggestions that the catechol-O-methyltransferase polymorphism may exert its effects by modulating prefrontal dopamine function, but few other neurocognitive measures have been examined, leaving open questions about phenotypic specificity. METHODS: We examined the effects of the catechol-O-methyltransferase Val(158)Met polymorphism in 58 individuals with chronic schizophrenia who completed a battery of 15 neurocognitive tests, which were reduced to four reliable neurocognitive domain scores. We examined the effects of genotype on these four domains and on global neurocognitive ability. RESULTS: The Met allele was associated with better performance in the Processing Speed and Attention domain, but not with other domain scores measuring executive and visuoperceptual functions, declarative verbal learning and memory, simple motor ability, or global neurocognitive function. Genotype shared approximately 11% of variance with Processing Speed and Attention scores, and approximately 2% of variance with Wisconsin Card Sorting Test scores. CONCLUSIONS: The findings provide independent support for the hypothesis that the catechol-O-methyltransferase Val(158)Met polymorphism influences neurocognitive function in schizophrenia, and suggest that the functional effects may be expressed on measures of Processing Speed and Attention. This information may prompt reconsideration of the "prefrontal dopamine" hypothesis and invites examination of a broader range of effects in efforts to refine the neurocognitive phenotype that is most relevant to variation in catechol-O-methyltransferase expression.

Adult↗

PubMed2002

Rapid and sensitive determination of nalmefene in human plasma by gas chromatography-mass spectrometry.

A rapid gas chromatography-mass spectrometric method for the determination of nalmefene in human plasma is described. The procedure involves protein precipitation, extraction with ethanol-chloroform mixture and derivatization with pentafluropropionic anhydride. The deuterated analog of nalmefene, 6beta-naltrexol-d(7), was used as the internal standard. Quantitation was achieved on a HP-1 column (12 mx0.2 mm I.D.) with negative chemical ionization (NCI) using methane:ammonia (95:5) as the reagent gas. The standard curves were fitted using a quadratic equation with the curve encompassing a range of 0.5 to 200 ng/ml, and the intra- and inter-assay variations for three different nalmefene levels were less than 10% throughout. The limit of quantitation was found to be 0.5 ng/ml. The method described is highly specific and reproducible, and could also be applied for the determination of naltrexone and 6beta-naltrexol. Application of the method to actual human plasma samples is demonstrated.

Gas Chromatography-Mass Spectrometry↗

PubMed2002

Dexmedetomidine increases the cocaine seizure threshold in rats.

BACKGROUND: Central alpha adrenoceptors have been demonstrated to play an important role in the control of seizure activity; moreover, alpha adrenoceptors have been linked to electroencephalogram changes associated with cocaine. The purpose of this study was to determine if dexmedetomidine, a highly selective alpha -adrenoceptor agonist, alters the threshold for cocaine-induced seizure activity in rats. METHODS: Sprague-Dawley rats received a cocaine infusion (1.25 mg x kg(-1) x min(-1)) followed 15 min later by the coinfusion of either dexmedetomidine (20-microg/kg intravenous bolus followed by an infusion of 1 microg x kg(-1) x min(-1), CD group, n = 8) or an equal volume of saline (CS group, n = 8). Dexmedetomidine or saline were coinfused with cocaine until the onset of cocaine-induced seizures. Dopamine concentrations in the nucleus accumbens were measured by microdialysis paired with chromatography. To determine if changes in extracellular dopamine were related to the seizures, dopamine (1 microm) was continuously delivered to the nucleus accumbens in a separate group (DACD group, n = 6) retrograde microdialysis. These rats then received an intravenous cocaine infusion followed by dexmedetomidine in the same manner as the CD group. RESULTS: Dexmedetomidine significantly increased the dose of cocaine necessary to produce seizures. Seizures occurred at 25.0 +/- 7.7 and 49.3 +/- 14.8 min in CS and CD, respectively (P < 0.001). The ratio of the percent increase in accumbal dopamine to the cocaine dose at the onset of seizure activity was significantly lower in CD, 39.9 +/- 16.5, compared to CS, 82.2 +/- 46.5 (P = 0.04). Intraaccumbal administration of dopamine prevented the effects of dexmedetomidine on the cocaine seizure threshold. CONCLUSIONS: These data suggest that dexmedetomidine increases the cocaine-induced seizure threshold possibly a mechanism related to the attenuation of the extracellular dopaminergic neurotransmitter response to cocaine.

Animals↗

PubMed2002

Antipsychotic-induced weight gain and therapeutic response: a differential association.

This study investigated the association between antipsychotic-induced weight gain and therapeutic response to haloperidol and three commonly used atypical neuroleptic medications in schizophrenia and schizoaffective disorder. The subjects were 151 patients enrolled in a double-blind experiment with a duration of 14 weeks comparing the therapeutic efficacy of haloperidol (n = 36), clozapine (n = 38), olanzapine (n = 38), and risperidone (n = 39). Absolute and relative (%) gain in body weight and body mass index (BMI) was determined for the entire duration of the double-blind treatment period; therapeutic response was assessed by the total score and the individual subscales of the Positive and Negative Symptom Scale. Compared with the pretreatment baseline, results indicated that for olanzapine and clozapine, therapeutic response was closely related to an absolute and relative gain in weight and to a gain in BMI. No association between weight gain and therapeutic response was found for risperidone and haloperidol. These findings suggest that patients who are likely to have the maximal benefits of olanzapine or clozapine treatment for symptom alleviation are at the highest risk of a clinically significant increase in weight gain.

Adult↗

PubMed2002

Clozapine, olanzapine, risperidone, and haloperidol in the treatment of patients with chronic schizophrenia and schizoaffective disorder.

OBJECTIVE: The authors compared the efficacy and safety of three atypical antipsychotics (clozapine, olanzapine, and risperidone) with one another and with haloperidol in the treatment of patients with chronic schizophrenia or schizoaffective disorder. METHOD: In a double-blind trial, 157 inpatients with a history of suboptimal treatment response were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol for 14 weeks (an 8-week escalation and fixed-dose period followed by a 6-week variable-dose period). RESULTS: Clozapine, risperidone, and olanzapine (but not haloperidol) resulted in statistically significant improvements in total score on the Positive and Negative Syndrome Scale. Improvements seen in total and negative symptom scores with clozapine and olanzapine were superior to haloperidol. The atypical drugs, particularly olanzapine and clozapine, were associated with weight gain. CONCLUSIONS: The effects of atypical antipsychotics in this population were statistically significant but clinically modest. The overall pattern of results suggests that clozapine and olanzapine have similar general antipsychotic efficacy and that risperidone may be somewhat less effective. Clozapine was the most effective treatment for negative symptoms. However, the differences among treatments were small.

Adolescent↗

PubMed2002

Low testosterone levels in elderly men with dysthymic disorder.

OBJECTIVE: A decline in hypothalamic-pituitary-gonadal (HPG) axis function is often seen in elderly men, and dysthymic disorder is common. Symptoms of both HPG axis hypofunction and dysthymic disorder include dysphoria, fatigue, and low libido. The authors compared total testosterone levels in three groups of elderly men. METHOD: Total testosterone levels were measured in subjects who met DSM-IV criteria for major depressive disorder (N=13) or dysthymic disorder (N=32) and a comparison group (N=175) who had participated in an epidemiological study of male aging and had scored below the median on the Center for Epidemiologic Studies Depression Scale, a well-validated, self-report depression symptom inventory. RESULTS: There were no differences among the three groups in measured demographic variables, including age and weight. Median testosterone levels varied for those with dysthymic disorder (295 ng/dl), major depressive disorder (425 ng/dl), and no depression (423 ng/dl). A test for differences in central tendency showed a statistically significant difference among the three groups. Post hoc pairwise comparisons revealed statistically significant differences between those with dysthymic disorder and those with major depressive disorder and no depression. CONCLUSIONS: Total testosterone levels were lower in elderly men with dysthymic disorder than in men with major depressive disorder and men without depressive symptoms. Dysthymic disorder in elderly men may be related to HPG axis hypofunction.

Age Factors↗

PubMed2002

Neurocognitive effects of clozapine, olanzapine, risperidone, and haloperidol in patients with chronic schizophrenia or schizoaffective disorder.

OBJECTIVE: Newer antipsychotic drugs have shown promise in ameliorating neurocognitive deficits in patients with schizophrenia, but few studies have compared newer antipsychotic drugs with both clozapine and conventional agents, particularly in patients who have had suboptimal response to prior treatments. METHOD: The authors examined the effects of clozapine, olanzapine, risperidone, and haloperidol on 16 measures of neurocognitive functioning in a double-blind, 14-week trial involving 101 patients. A global score was computed along with scores in four neurocognitive domains: memory, attention, motor function, and general executive and perceptual organization. RESULTS: Global neurocognitive function improved with olanzapine and risperidone treatment, and these improvements were superior to those seen with haloperidol. Patients treated with olanzapine exhibited improvement in the general and attention domains but not more than that observed with other treatments. Patients treated with risperidone exhibited improvement in memory that was superior to that of both clozapine and haloperidol. Clozapine yielded improvement in motor function but not more than in other groups. Average effect sizes for change were in the small to medium range. More than half of the patients treated with olanzapine and risperidone experienced "clinically significant" improvement (changes in score of at least one-half standard deviation relative to baseline). These findings did not appear to be mediated by changes in symptoms, side effects, or blood levels of medications. CONCLUSIONS: Patients with a history of suboptimal response to conventional treatments may show cognitive benefits from newer antipsychotic drugs, and there may be differences between atypical antipsychotic drugs in their patterns of cognitive effects.

Adult↗

PubMedDate not supplied

Modified dexamethasone suppression-corticotropin-releasing hormone stimulation test: A pilot study of young healthy volunteers and implications for alcoholism research in adolescents and young adults.

The key neuroendocrine component of a response to stress is the hypothalamic-pituitary-adrenocortical (HPA) system. Abnormalities in the HPA system have been implicated in the pathophysiology of psychiatric disorders such as depression, post-traumatic stress disorder, alcoholism and suicide. The dexamethasone suppression test (DST) is the most frequently used test to assess HPA-system function in psychiatric disorders. This neuroendocrine test consists of the administration of a low dose of dexamethasone at 11 pm and the measurement of cortisol levels at one or more time points on the following day. After corticotropin-releasing hormone (CRH) became available for clinical studies, the DST was combined with CRH administration. In this test, patients are pretreated with a single dose of dexamethasone at 11 pm and receive human CRH intravenously at 3 pm the following day. The resulting DST-CRH test proved to be much more sensitive in detecting HPA system alterations than the DST. We have modified the DST-CRH test and used ovine CRH instead of human CRH in a pilot study of a group of young healthy volunteers. Results indicated that it produces results similar to the results obtained with human CRH. This suggests that ovine CRH can be used in psychiatric research. Alcoholism is associated with abnormalities in HPA function. Nonalcoholic subjects with a family history of alcoholism exhibit lower plasma ACTH and beta-endorphin as well as lower ACTH, cortisol, and beta-endorphin responses to psychological stress and CRH stimulation. This suggests that in children of alcoholics, alterations in the mechanisms that regulate HPA axis activity predate the development of alcohol dependence and may be considered inherited traits. Therefore, studies of the HPA system in persons at risk for alcoholism may help understand the neurobiological mechanisms of predisposition to alcoholism.

Adolescent↗

PubMedDate not supplied

Usefulness of plasma haloperidol levels for monitoring clinical efficacy and side effects in Alzheimer patients with psychosis and behavioral dyscontrol.

OBJECTIVE: This study investigated whether measurement of plasma levels may be useful in monitoring clinical efficacy and side effects during oral haloperidol (HL) treatment of psychosis and behavioral dyscontrol in patients with Alzheimer disease (AD). METHODS: After a single-blind placebo period of 1 week, 71 outpatients with AD were randomized to a 6-week, double-blind, placebo-controlled trial of HL 2 mg-3 mg/day (standard dose), HL 0.5 mg-0.75 mg/day (low dose), or placebo, with plasma levels for HL drawn at the end of 6 weeks. RESULTS: Of the 40 patients who received active HL for 6 weeks, 35 had plasma levels drawn. Plasma levels were all below the lower limit of the postulated therapeutic range in schizophrenia. Nonetheless, HL plasma level significantly correlated with clinical efficacy as measured by reduction in Brief Psychiatric Rating Scale Total score, Psychosis factor, and Hostile-Suspiciousness factor, the Behavioral Syndromes Scale for Dementia Psychomotor Agitation scale, and with the severity of extrapyramidal side effects (EPS). Oral dose did not significantly correlate with any of these efficacy or side-effect measures. Plasma levels significantly correlated with HL dose. When both HL dose and HL plasma level were included as independent variables in linear-regression analyses, only HL plasma level was a significant predictor of efficacy and EPS. CONCLUSION: Measurement of HL plasma levels may have potential usefulness as an adjunct in monitoring treatment response to oral HL in AD patients with psychosis or disruptive behavior.

Aged↗