Evidence of the role of the vagal nerves as a monitor in the gastrointestinal-renal axis of natriuresis in human: Effects of vagotomy.

This study aimed to investigate the mechanism of gastrointestinal regulation of natriuresis. Sixteen subjects without (group I) and sixteen subjects with a truncal vagotomy (group II), were given a daily diet of 18mmol of sodium for 5days (D1-D5). The sodium deficit for this period was calculated for each subject and on the morning of day-6 (D6), their cumulative deficit (E) was given as 3% NaCl. In both groups the subjects were divided to receive the hypertonic saline either orally (Ior, IIor) or intravenously (Iiv, IIiv). During the period of low sodium diet when compared to group II subjects of group I (1) had a greater weight loss (p<0.005), (2) demonstrated a larger drop in pulse pressure (p<0.005), (3) achieved a positive sodium equilibrium later (D5 vs D4) and (4) developed a greater sodium deficit (p<0.005). During the two 12h periods of D6, both Ior and Iiv exhibited greater natriuresis during the first 12h period (p<0.0001) whereas both IIor and IIiv did so during the second 12h period (p<0.0001). On D6 Ior excreted the greatest percentage of E (E%; 35.63%±3.12%, p<0.0001) compared to Iiv (17.06%±1.78%), IIor (16.03%±3.54%) and IIiv (15.39%±2.77%) whereas E% was not different between the other subgroups. These results indicate that the differential natriuresis between oral and intravenous sodium loading in previously sodium deprived subjects, is due to a mechanism in which the vagal nerves play a significant role as part of neural reflex or via a natriuretic hormone.

Prevalence, awareness, treatment and control of hypertension in Hellas, Greece: the Hypertension Study in General Practice in Hellas (HYPERTENSHELL) national study.

BACKGROUND: The Hypertension Study in General Practice in Hellas (Hypertenshell) is a cross-sectional study (much like the National Health and Nutrition Examination Study) for assessing the prevalence, level of awareness, treatment, and control of hypertension in Greece. METHODS: The study was conducted with the collaboration of physicians in 98 Health Centers across Greece. Participants were interviewed about lifestyle, and blood pressure (BP) measurements were taken on two clinical visits for verification of diagnosis and control of hypertension. Hypertension was defined as systolic BP > or =140 mm Hg or diastolic BP > or =90 mm Hg, or current treatment with antihypertensive drugs; the same threshold was used for assessing control of hypertension. RESULTS: A total of 11,950 individuals participated and data for 11,540 were analyzed, comprising 0.1% of the Greek population. The prevalence of hypertension was 31.1% (men 33.6%, women 28.4%); among elderly individuals (>65 years) the prevalence was higher (65.4%). Of the hypertensive individuals, 39.8% did not know that had hypertension, yielding an awareness of 60.2%; in addition, 12.4% were aware but not treated (men 13.1%, women 11.8%). In all, 51.2% (1838) of hypertensive subjects were treated; 67.2% (1235) were treated but not controlled (men 66.7%, women 67.7%); and 32.8% (603) were treated and controlled (men 33.3%, women 32.3%). CONCLUSIONS: The results of the Hypertenshell Study indicate that hypertension is a common risk factor for cardiovascular disease in the Greek population. Awareness, treatment, and control of hypertension are comparable to the best rates of control of hypertension given for the problem, but there is a considerable potential for further improvement in the control of this disease.

Prognostic significance of renal function in elderly patients with isolated systolic hypertension: results from the Syst-Eur trial.

Several reports suggest that markers of renal function such as serum creatinine, serum uric acid, and urinary excretion of protein may be related to cardiovascular complications and mortality. This study analyzed the data from the Syst-Eur trial, which was a randomized, placebo-controlled, double-blind intervention trial in elderly patients with isolated systolic hypertension. The purpose was to evaluate whether serum levels of creatinine and uric acid and urinary protein excretion at entry are related to subsequent morbidity and mortality. Incidence rates of total mortality, cardiovascular mortality, stroke (fatal as well as nonfatal), coronary events, and all cardiovascular endpoints were calculated for each quintile of serum creatinine or serum uric acid or for each category of protein excretion (none, trace, and overt). Crude and adjusted relative hazard rates were also determined for each 20 micro M increase in serum creatinine, each 50 micro M increase in serum uric acid, and for each protein excretion category. Even when adjusted for age, gender, and various other covariates, serum creatinine was significantly associated with a worse prognosis. There was an U-shaped relationship between serum uric acid and total mortality, but otherwise no obvious relationships were detected between serum uric acid levels and complications when appropriate adjustments were made for confounding variables. Proteinuria at entry was a significant predictor of total mortality and all cardiovascular endpoints. It is concluded that higher levels of serum creatinine and trace or overt proteinuria are associated with an increased number of cardiovascular events and with a higher mortality in patients with isolated systolic hypertension.