[Influence factors of salt-sensitive hypertension and responses of blood pressure and urinary sodium and potassium excretion to acute oral saline loading among essential hypertensive patients].

OBJECTIVE: To explore the influence factors of salt-sensitive hypertension and to observe changes of blood pressures and urinary sodium and potassium excretion in response to acute oral saline loading among essential hypertensive patients in China. METHODS: Essential hypertensive patients from Beijing Jinzhan second community were included in this study. Salt-sensitivity was determined via the improved Sullivan's acute oral saline loading and furosemide volume-depletion tests. Binary logistic regression analysis was applied to explore influence factors of salt-sensitive hypertension. Acute oral saline loading induced changes on blood pressures and urinary sodium and potassium excretion were observed. RESULTS: Sixty-three salt-sensitive hypertensive patients were classified out of a total of 342(18.4%) essential hypertensive patients. Salt-sensitive patients were elder than the non-salt-sensitive patients (P < 0.05) . Binary logistic regression analysis showed that age (OR = 1.744, 95%CI:0.922-3.300, P > 0.05) , gender (OR = 0.728, 95%CI:0.374-1.415, P > 0.05) , total cholesterol level (OR = 1.168, 95%CI:0.882-1.547, P > 0.05) and 24-hour urinary sodium (OR = 0.998, 95%CI:0.995-1.002, P > 0.05) were not influencing factors of salt-sensitivity among essential hypertensive patients. Bivariate general linear models for repeated measures showed that there were significant statistical differences on blood pressures and urinary electrolytes concentrations between the beginning of trials, 2 hours after acute saline loading and 2 hours after furosemide volume-depletion(all P < 0.01). There was a greater blood pressures change in salt-sensitive patients than in non-salt-sensitive patients(all P < 0.01) while urinary electrolytes concentrations change was similar between two groups(all P > 0.05). CONCLUSIONS: Age, gender, total cholesterol level and 24-hour urinary sodium are not influencing factors of salt-sensitivity among essential hypertensive patients in this study. Impaired pressure natriuresis during acute oral saline loading and furosemide volume-depletion tests is presented in salt-sensitive essential hypertensive patients.

The DNA methylation profile within the 5'-regulatory region of DRD2 in discordant sib pairs with schizophrenia.

Studies of discordance in monozygotic twins have demonstrated that environmental effects play an important role in the pathogenesis of schizophrenia. DNA microarray analysis has revealed upregulation of the DRD2 gene in peripheral blood lymphocytes of schizophrenic patients. We hypothesized that this expression alteration could involve the DNA (CpG) methylation status that is implicated to the transcription status of the gene and in this study we used bisulfited sequence analysis to determine the DNA methylation status of a typical CpGs island within the 5'-regulatory region of DRD2 in peripheral blood lymphocytes from 48 discordant sib pairs suffering from schizophrenia. We found that the methylated cytosines occurred mainly in three clusters. No statistically significant difference in frequency of site-specific cytosine methylation modification of DRD2 between patients and normal controls was found nor did we find any significant association between sex, age on admission or age at onset of schizophrenia and methylated cytosines of DRD2. Our study did not support the hypothesis that site-specific cytosine methylation of DRD2 plays a role in the psychopathology of schizophrenia.