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In a previous study, we found an association between 5-hydroxytryptamine (serotonin) receptor 2C (HTR2C) polymorphisms and the occurrence of the metabolic syndrome in patients using antipsychotics. In the current study, we set out to replicate our findings in another sample of patients and to explore in a pooled analysis of both samples the influence of the effect of individual antipsychotics. Data for this cross-sectional study came from 2 different samples, the original sample (n = 112) and the replication sample (n = 164). Primary end point was the prevalence of the metabolic syndrome as classified by a modified version of the National Cholesterol Education Program's Adult Treatment Panel III. Primary determinants were polymorphisms in the promoter region of the HTR2C gene [HTR2C:c.1-142948(GT)n, rs3813929 (-759 C/T), and rs518147 (-697 G/C)] and an intragenic polymorphism (rs1414334:C>G). The variants of HTR2C:c.1-142948(GT)n (odds ratio [OR], 1.69; 95% confidence interval [CI], 0.75-3.81) and rs1414334 (OR, 2.35; 95% CI, 0.96-5.77) were not significantly associated with the metabolic syndrome in the replication sample but did show significance in the pooled analysis (OR, 2.09; 95% CI, 1.12-3.91; and OR, 2.35; 95% CI, 1.19-4.62, respectively). The variant rs1414334 C allele was specifically associated with the metabolic syndrome in patients using clozapine (OR, 9.20; 95% CI, 1.95-43.45) or risperidone (OR, 5.35; 95% CI, 1.26-22.83). This study extends previous findings to a larger sample of patients and implicates specific antipsychotic drugs. The increased risk for the metabolic syndrome is particularly strong in carriers of the rs1414334 C allele using clozapine or risperidone.

The use of antipsychotics is associated with metabolic side effects, which put patients with schizophrenia or related disorders at risk for cardiovascular morbidity. The high interindividual variability in antipsychotic-induced metabolic abnormalities suggests that genetic makeup is a possible determinant. In this cross-sectional study, we investigated whether genotypes of the HTR2C receptor are associated with the metabolic syndrome in patients using antipsychotics. Patients were identified from a schizophrenia disease management program. In this program, patients' blood pressure, triglycerides, high-density lipoprotein-cholesterol, and waist circumference are measured regularly during follow-up. The primary end point of our study was the prevalence of the metabolic syndrome as classified by a modified version of the National Cholesterol Education Program's Adult Treatment Panel III. Primary determinants were polymorphisms in the HTR2C receptor gene (HTR2C:c

The importance of the head in dissipating body heat under hot conditions is well recognised, although very little is known about local differences in sweat secretion across the surface of the head. In this study, we focused on the intra-segmental distribution of head sweating. Ten healthy males were exposed to passive heating and exercise-induced hyperthermia (36 degrees C, 60% relative humidity, water-perfusion suit: 46 degrees C), with ventilated sweat capsules (3.16 cm(2)) used to measure sweat rates from the forehead and nine sites inside the hairline. Sweat secretion from both non-hairy (glabrous) and hairy areas of the head increased linearly with increments in work rate and core temperature, with heart rate and core temperature peaking at 175 b min(-1) (+/-6) b min(-1) and 39.2 degrees C (+/-0.1). The mean sweat rate during exercise for sites within the hairline was 1.95 mg cm(-2) min(-1). However, the evolution of this secretion pattern was not uniformly distributed within the head, with the average sweat rate for the top of the head being significantly lower than at the anterior lateral aspect of the head (P < 0.05), and representing only 30% of the forehead sweat rate (P < 0.05). It is hypothesised that these intra-segmental observations may reflect variations in the local adaptation of eccrine glands to differences in local evaporation associated either with bipedal locomotion, which will influence forehead sweating, or the hidromeiotic suppression of sweating, which impacts upon sweat glands within the hairline.

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