Search PubMed⌕ Search

Biomedical subjects

R M Post

Publications and source records attributed to R M Post.

At least 343 records · Page 19Linked to original sources
PubMed1983

CSF dopamine beta-hydroxylase in schizophrenia.

Dopamine beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine, was measured in the CSF of 30 schizophrenic patients and 27 normal controls. The CSF DBH activity in the patients was not significantly different from that in controls. Levels of CSF DBH activity in individual patients were highly constant over time and were not influenced by clinical state or neuroleptic treatment. Low levels of DBH in CSF did significantly relate to good social and sexual functioning, good prognosis, less symptoms between hospitalizations, and excellent clinical response to neuroleptic treatment. We speculate from these data that low brain DBH activity may produce a type of vulnerability to psychotic decompensation and thereby influence the clinical course, although it does not cause schizophrenia, in general. Low CSF DBH activity may delineate a "reactive" subgroup from the heterogenous population of patients with diagnoses of schizophrenia.

Adolescent↗
PubMed1983

Thinking disorder in depression.

This experiment demonstrated abstract reasoning deficits in depressed patients and detailed some of the components of cognition that may determine such deficits. Subjects were given a discrimination learning problem in which possible solutions had to be formulated and tested against new information. Depressed subjects performed more poorly on the task than controls. Two types of errors--inability to narrow down the set of possible solutions (poor "focusing") and perseveration on disconfirmed hypotheses--hampered the performance of depressed but not control subjects. While logic, memory, and attention were intact at an elementary level, the inability to coordinate these functions in a complex task appeared to be an important feature of the depressive impairment.

Adult↗
PubMed1983

Carbamazepine and its -10,11-epoxide metabolite in plasma and CSF. Relationship to antidepressant response.

Levels of carbamazepine and its -10,11-epoxide metabolite were measured in plasma and CSF of affectively ill patients treated only with carbamazepine for an average of 33 days at an average dosage of 1,055 mg/day. The CSF levels of carbamazepine were 2.06 micrograms/mL (ie, 31% of plasma levels, which equaled 6.55 micrograms/mL); CSF -10,11-epoxide concentrations averaged 0.91 micrograms/mL in 18 subjects (63% of those found in plasma). Carbamazepine levels in plasma or CSF were not related to degree of antidepressant or antimanic response. In contrast, concentrations of the -10,11-epoxide metabolite were correlated with the degree of antidepressant response. This preliminary study suggests the possibility that the -10,11-epoxide metabolite of carbamazepine may be related to the degree of clinical efficacy in affectively ill patients and may thus possess active psychotropic properties in man in addition to its reported anticonvulsant effects in animals.

Adult↗
PubMed1983

Properties of two benzodiazepine binding sites in spinal cord.

Two types of benzodiazepine receptors were demonstrated in spinal cord. Binding to one of these sites (neuronal) was sensitive to the centrally active benzodiazepine, clonazepam, and binding was enhanced both by chloride and GABA. The second site was sensitive to 7-chloro-1,3-dihydro-1-methyl-5-(p-chlorophenyl) 2H-1,4-benzodiazepine-2-one (R05-4864) and thus is similar to the site characteristic of non-neuronal tissue. Binding to the neuronal site was inhibited by the putative glycine antagonist, strychnine, both in spinal cord and brain. This inhibition may account for the reported anti-GABAergic properties of strychnine and does not appear to be related to the glycine receptor.

Animals↗
PubMed1983

Relationship of cortisol hypersecretion to brain CT scan alterations in depressed patients.

Preliminary data showing a correlation between urinary free cortisol levels and ventricular-brain ratio in 10 affectively ill patients are presented. The literature on hypercortisolism and computed tomography (CT scan) abnormalities is reviewed. The authors suggest that the increased cortisol production in some psychiatric patients might be capable of altering the gross structure of the brain and that such alterations might be reversible.

Adult↗
PubMed1983

CSF 5HIAA and personal and family history of suicide in affectively ill patients: a negative study.

Personal and family histories of suicidality were gathered in 45 patients who met Research Diagnostic Criteria for major affective disorder (n = 32, bipolar; n = 13, unipolar) and compared to CSF values of 5HIAA obtained by two different assays (n = 20, fluorometric; n = 25, high performance liquid chromatography). In separate analyses of the two assay groups, patients who had made a suicide attempt were not significantly different from those who had not in terms of 5HIAA value or family history of suicidality. Furthermore, in suicide attempters, 5HIAA was unrelated to the severity of the attempt.

Adult↗
PubMed1983

Biochemical effects of carbamazepine: relationship to its mechanisms of action in affective illness.

Carbamazepine has a unique spectrum of clinical efficacy in paroxysmal pain syndromes and epilepsy, as well as in affective illness. Evidence of its therapeutic effects in lithium-resistant manic-depressive illness and schizoaffective illness is reviewed. The biochemical effects of carbamazepine as they might be related to either its anticonvulsant or psychotropic properties are presented and discussed. Carbamazepine alters classical neurotransmitter and second messenger systems, as well as a variety of neuropeptides which could relate to mechanisms of action or side effects. Comparison and contrast of the biological effects of carbamazepine with classical treatment agents, such as lithium carbonate, tricyclic antidepressants, and neuroleptics may help elucidate mechanisms underlying the pathophysiology of the mood disorders.

Bipolar Disorder↗
PubMed1983

Processing of emotional properties of stimuli by depressed and normal subjects.

This study investigated whether depressed subjects differ from controls in their ability to appreciate emotional aspects of verbal material, or in their use of emotional qualities of stimuli in learning and remembering. When asked to rate the degree of emotionality of words, depressed subjects did so essentially identically with controls. However, despite apparently similar evaluatory processing, the depressed failed to remember as well as controls. Depressed subjects were more dependent than controls on both high emotionality and high stimulus concreteness for recognition memory, but were less benefited by these properties in free recall. While providing no evidence for deficits specific to emotionality, our results suggest that relatively shallow processing of semantic aspects of stimuli may be an important factor in the memory impairment of depression.

Adult↗
PubMed1983

5-hydroxytryptamine and depression: a model for the interaction of normal variance with pathology.

1 Theories linking 5-hydroxytryptamine (5-HT) with depression are briefly reviewed. The various experimental strategies adopted to investigate this relationship, examination of autopsy data, CSF metabolite data, 5-HT re-uptake patterns in human blood platelets and imipramine binding studies in human platelets, are discussed. 2 Recent studies of 5-hydroxyindole acetic acid (5-HIAA) levels in cerebrospinal fluid have revealed a linkage between low 5-HIAA levels and suicide, aggression and impulsivity. Decreases in the number of imipramine binding sites have also been found in brains of suicide victims. 3 The available data lead to the conclusion that decreased 5-hydroxytryptaminergic function may be associated with an increased risk of depression, suicide, and some types of aggression.

Aggression↗
PubMed1983

Altered lateralization of cognitive processes in depressed women.

Eighteen normal men and women had a left hemisphere advantage for processing a verbal task, but depressed women showed a trend toward right hemisphere superiority. In depression the right hemisphere may share functions performed exclusively by the left hemisphere in normal subjects. Altered laterality may be a trait of depression-prone people or a change related to depressive episodes themselves. In the latter case, the right hemisphere may be compensating for relative deactivation of the dominant left hemisphere.

Adult↗
PubMed1983

Prophylactic efficacy of carbamazepine in manic-depressive illness.

Seven patients with rapidly cycling, lithium-resistant affective illness were followed for an average of 1.7 years during prophylactic treatment with carbamazepine administered on either a blind or an open basis. The number of manic and depressive episodes per year decreased significantly--from 16.4 before treatment to 5.6 during carbamazepine treatment; severity and duration of episodes were also reduced. Six of seven patients relapsed after carbamazepine dose reduction or discontinuation. These preliminary data add further support to the growing evidence that carbamazepine may be useful in the acute and prophylactic treatment of some lithium-resistant patients.

Antipsychotic Agents↗
PubMed1983

The effect of lithium on the osmoregulation of arginine vasopressin secretion.

The effect of lithium on the plasma arginine vasopressin (AVP) response to the iv infusion of 5% saline was determined in six patients with primary effective disorder. Lithium did not significantly affect baseline weight, plasma osmolality, sodium, or AVP levels. However, lithium significantly increased the mean rate of change or the sensitivity of the plasma AVP response to the osmotic stimulus (from 0.42 +/- 0.17 to 1.08 to 0.24 pg/ml/mosmol/kg; P less than 0.025, by paired t test). This change was associated with a slight but significant increase in the precision of the response, as reflected in the correlation coefficient, but there was no difference in the calculated intercept or osmotic threshold for AVP secretion. This study indicates that patients on lithium do not, as previously suggested, show partial central diabetes insipidus. Rather, AVP secretion seems to be enhanced. Moreover, the mechanism of this enhancement is a specific increase in the sensitivity of the osmoreceptor rather than a lowering of the osmotic threshold for AVP secretion. The effect of lithium cannot be clearly accounted for by any of the physiological variables known to influence the sensitivity of the system and is probably due to an effect of the drug on the level or activity of neuromodulators which influence the function of hypothalamic osmoreceptors.

Adult↗
PubMed1983

Carbamazepine diminishes the sensitivity of the plasma arginine vasopressin response to osmotic stimulation.

Carbamazepine, a drug used to treat manic-depressive illness, has been reported to possess antidiuretic properties, but its effects on arginine vasopressin (AVP) secretion are controversial. Consequently, we examined plasma AVP secretion during hypertonic (5%) saline infusion in seven manic-depressive patients while on placebo and after 3-5 weeks of carbamazepine treatment. We also measured carbamazepine's effects on basal levels of the hormone in cerebrospinal fluid. Carbamazepine significantly reduced the sensitivity of the plasma AVP response to osmotic stimulation without affecting the osmotic threshold for AVP secretion. Moreover, carbamazepine did not affect baseline weight, plasma osmolality, plasma sodium, urine output, plasma AVP, or cerebrospinal fluid AVP. Although the functional significance of these findings remain to be fully determined, the fact that carbamazepine significantly reduced AVP secretion without inducing diuresis supports previous suggestions that carbamazepine enhances renal responsivity to available AVP. In addition, since carbamazepine failed to affect the osmotic threshold, the reported cases of carbamazepine-induced inappropriate AVP secretion and water intoxication must be very uncommon and probably represent idiosyncratic responses.

Arginine Vasopressin↗
PubMed1983

Cerebrospinal fluid probenecid studies: a reinterpretation.

Probenecid is used to block the transport of acid monoamine metabolites from cerebrospinal fluid (CSF), on the assumption that the resultant rise in CSF concentrations of the metabolites will reflect presynaptic "turnover" of the parent monoamine. However, CSF levels of probenecid correlate with CSF levels of the metabolite, suggesting that the blockade is incomplete at the probenecid levels obtained in human studies. This article reviews the literature on CSF probenecid-metabolite correlations and presents data demonstrating variations in the correlations across diagnostic groups. These cross-diagnostic variations may be due to group differences in membrane transport characteristics and and confound attempts to "correct for" CSF probenecid concentrations in studies of monoamine turnover.

Biological Transport↗
PubMed1983

Reduced plasma and CSF gamma-aminobutyric acid in affective illness: effect of lithium carbonate.

Plasma and CSF gamma-aminobutyric acid (GABA) levels were determined in patients with affective illness and normal volunteers. Plasma GABA was significantly lower in the medication-free euthymic bipolar group (n = 23, p = 0.03) compared to normal volunteers (n = 36). Lithium-treated euthymic bipolar patients (n = 26) tended to have higher plasma GABA levels (p = 0.09) than the medication-free euthymic bipolar group. Plasma GABA in nine patients, measured in the euthymic state on and off lithium, was higher during lithium treatment (p less than 0.02). In CSF, GABA was found to be significantly lower in a group of euthymic medication-free unipolar and bipolar patients (n = 9) compared to normal volunteers (n = 39, p less than 0.02). CSF GABA, on and off lithium in four bipolar patients, was significantly higher during lithium treatment (p less than 0.02). This effect of lithium, increasing CSF and plasma GABA, may be related to its mechanism of therapeutic action.

Adult↗