Biomedical subjects

Avi Valevski

Publications and source records attributed to Avi Valevski.

5 recordsLinked to original sources

PubMed2004

Influence of 17beta-estradiol on the synthesis of reduced neurosteroids in the brain (in vivo) and in glioma cells (in vitro): possible relevance to mental disorders in women.

Brain neurosteroids modulate gamma-aminobutyric acid type A (GABAA) receptor activity, thereby playing a role in mood disorders. Alterations in 17beta-estradiol (E2) and progesterone (P) are also known to play a significant role in psychopathology in women. The aim of the present study was to evaluate the synthesis of dihydroprogesterone (DHP), tetrahydroprogesterone (THP), and the activity of 5alpha-reductase (5alphaR) which regulates the reduction of P to DHP on exposure to supraphysiological levels of E2 in vitro (C6 glioma cells) and in vivo (mouse brain). The results showed that supraphysiological levels of E2 induced a decrease in the accumulation of both neurosteroids, probably by decreasing the activity of 5alphaR. We hypothesize that the high levels of E2 in pregnancy attenuate the increase in the conversion of P to THP in the brain and that the ratio of E2/P modulates the sedative effect of THP. This process may be relevant to psychopathological disorders that are ascribed to drastic alterations in estrogen levels, such as premenstrual syndrome, pregnancy-related mental disorders, and postpartum "blues".

20-alpha-Dihydroprogesterone↗

PubMed2003

Precautionary measures reduce risk of definite neuroleptic malignant syndrome in newly typical neuroleptic-treated schizophrenia inpatients.

Neuroleptic malignant syndrome (NMS) is a potentially lethal antipsychotic drug (APD)-induced thermoregulatory disturbance. We hypothesized that several precautionary measures taken after administeration of APDs might prevent progression to definite NMS. The study group included 657 consecutively admitted drug-free schizophrenia inpatients who received various typical APDs for 28 days. Specific predefined precautionary measures were employed for this group. The comparison group (n=192) consisted of typical APD-treated schizophrenia inpatients in whom such precautionary measures were not imposed. The study group exhibited a significantly lower incidence of definite NMS (1/657=0.2% versus 4/192=2.1%; P=0.01, odds ratio=13.96; 95% confidence interval 1.55-125.63). Antipsychotics were discontinued in 28 patients (28/657=4.3%) from the study group due to NMS (n=1) or early detection of potential NMS-related signs (probable abortive NMS) (n=27). Our findings suggest that specific precautionary measures can effectively reduce the incidence of definite NMS by approximately one order in newly medicated schizophrenia inpatients.

Adult↗

PubMed2002

Short-term treatment of post-traumatic stress disorder with naltrexone: an open-label preliminary study.

Eight patients (6 men and 2 women) with chronic post-traumatic stress disorder (PTSD) were treated with naltrexone 100-200 mg/day. Seven patients completed 2 weeks of treatment. A subtle and clinically insignificant improvement was noted in intrusive and hyperarousal symptoms (p < 0.05 for both), but not in avoidance symptoms. All patients demonstrated side effects which limited the targeted dose. It is suggested that the subtle positive effect of naltrexone and the hypersensitivity of these patients to its side effects do not encourage the use of naltrexone in the treatment of PTSD patients.

Adult↗

PubMed2002

Increased platelet vesicular monoamine transporter density in adult schizophrenia patients.

Vesicular monoamine transporter (VMAT2) plays a major role in the synaptic accumulation and release of monoamines. In the present study, we assessed high affinity [(3)H]dihydrotetrabenazine binding to platelet VMAT2 in a group of treated (n = 9) and untreated (n = 4) patients with schizophrenia and age- and sex-matched controls. Significantly elevated platelet VMAT2 density (B(max)) (53%, P<0.0001) was observed in the mixed population of schizophrenia patients. The affinity of the ligand (K(d)) to platelet VMAT2 was similar in both groups. The increased platelet VMAT2 density may indicate a schizophrenia-related hyperactivity of the monoaminergic system or an adaptive response to chronic drug treatment.

Adult↗

PubMed2002

Sexual function and behavior in social phobia.

BACKGROUND: Social phobia is a type of performance and interpersonal anxiety disorder and as such may be associated with sexual dysfunction and avoidance. The aim of the present study was to evaluate sexual function and behavior in patients with social phobia compared with mentally healthy subjects. METHOD: Eighty subjects participated in the study: 40 consecutive, drug-free outpatients with social phobia (DSM-IV) attending an anxiety disorders clinic between November 1997 and April 1999 and 40 mentally normal controls. The Structured Clinical Interview for DSM-IV Axis I Disorders and the Liebowitz Social Anxiety Scale were used to quantitatively and qualitatively assess sexual function and behavior. RESULTS: Men with social phobia reported mainly moderate impairment in arousal, orgasm, sexual enjoyment, and subjective satisfaction domains. Women with social phobia reported severe impairment in desire, arousal, sexual activity, and subjective satisfaction. In addition, compared with controls, men with social phobia reported significantly more frequent paid sex (p < .05), and women with social phobia reported a significant paucity of sexual partners (p < .05). CONCLUSION: Patients with social phobia exhibit a wide range of sexual dysfunctions. Men have mainly performance problems, and women have a more pervasive disorder. Patients of both genders show difficulties in sexual interaction. It is important that clinicians be aware of this aspect of social phobia and initiate open discussions of sexual problems with patients.

Adult↗