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Biomedical subjects

R Belmaker

Publications and source records attributed to R Belmaker.

16 recordsLinked to original sources

Transcranial magnetic stimulation in the treatment of psychiatric disorders.

Transcranial magnetic stimulation (TMS) is a new technology that applies the principles of electromagnetism to deliver an electrical field to the cerebral cortices. Well established in diagnostic electrophysiology, TMS is now being studied as a treatment for psychiatric disorders. Evidence suggests this technique is safe and acceptable to patients. The future may see the application of TMS in obsessive-compulsive disorder, post-traumatic stress disorder and mania. There is strong evidence that it will become an accepted treatment of depression.

Electric Stimulation Therapy↗

Cyclic AMP generation in medulla oblongata and hypothalamus of hypertension-prone and -resistant rats.

Accumulation of cAMP induced by noradrenaline (NA) was higher in the medulla oblongata (MO) of hypertension-prone (H) than in resistant (N) rats, 113 +/- 3 vs. 72 +/- 4 (p less than 0.01). In the hypothalamus (HYP) it was higher in N than in H rats, 148 +/- 8 vs. 92 +/- 6 (p less than 0.01). In both anterior and posterior HYP, the accumulation of cAMP was significantly higher in N than in H rats. cAMP accumulation, in the presence of increasing concentrations of phosphodiesterase inhibitor, showed significant strain differences in both MO and HYP. The observed strain differences in cAMP may be pertinent to the disparate susceptibility to hypertension of H and N rats.

Animals↗

Genetic control of human plasma creatine phosphokinase activity.

Plasma creatine phosphokinase (CPK) activity was determined in 14 monozygotic (MZ) and 14 dizygotic (DZ) twin pairs. The heritability indexes calculated for plasma CPK activity indicated support for the hypothesis that plasma CPK activity is under some genetic control. This finding is discussed in relation to various diseases in which plasma CPK activity is increased.

Creatine Kinase↗

Monoamine oxidase in chronic schizophrenia: Studies of hormonal and other factors affecting enzyme activity.

Reported reductions in the activity of platelet monoamine oxidase (MAO) in chronic schizophrenic patients might be contributed to by alterations in hormones, platelet numbers or other non-specific factors thought to affect enzyme activity. In this study, MAO activity in 27 patients with chronic schizophrenia was measured, using benzylamine as the substrate in an assay based on platelet counts instead of platelet protein, and was found to be markedly lower than mean MAO activity in 375 normal controls. These results were similar to those previously reported with tryptamine as a substrate for the enzyme. Serum testosterone, triiodothyronine, iron and iron-binding capacity were within normal ranges in individuals with reduced MAO activities. Platelet MAO activity remained stable over time in patients and controls.

Benzylamines↗

Neuroleptics reduce spinal fluid cyclic AMP in schizophrenic patient.

Cyclic AMP in the cerebrospinal fluid (CSF) was determined in a group of 10 schizophrenic patients before neuroleptic drug treatment and after a mean of 8 week's antipsychotic drug therapy. For 8 patients with marked to moderate treatment response a significant (p less than 0.01) decline in CSF cyclic AMP was observed. This result is consistent with the theory that blockade of postsynaptic dopamine receptors is a major mechanism of the antipsychotic action of neuroleptic drugs.

Acute Disease↗

A twin study of human red blood cell catechol-o-methyl transferase.

Significant sibling-sibling and within-family correlations of human red blood cell catechol-o-methyl transferase activity have suggested a high degree of genetic control over levels of activity of this catecholamine-related enzyme. However, family studies do not disentangle genetic from environmental similarities as causative of within-family correlations. We therefore undertook a human twin study using the monozygotic-dizygotic comparison method. Twelve pairs of monozygotic twins had an intraclass correlation of 90 in red blood cell catechol-o-methyl transferase activity, and seven pairs of dizygotic twins had an intraclass correlations of 37. Heritability of the enzyme activity was estimated by different methods as between 68-100 per cent.

Adolescent↗

Reduced monoamine oxidase activity in platelets: a possible genetic marker for vulnerability to schizophrenia.

Monoamine oxidase activity in blood platelets was measured, with [(14)C]tryptamine as substrate, in 13 monozygotic twin pairs discordant for schizophrenia and in 23 normal volunteers. The monoamine oxidase activity of both schizophrenic and nonschizophrenic co-twins was significantly lower than it was for the normals, and it was highly correlated between twins. In addition, there was a significant inverse correlation between a measure of the degree of the schizophrenic disorder and the monoamine oxidase activity. These data suggest, but do not prove, that reduced platelet monoamine oxidase activity may provide a genetic marker for vulnerability to schizophrenia.

Adult↗