ABSTRACT
The clinical characteristics of the 4,170 hypertensive patients referred to the Dunedin Clinic from 1950 to 1989 have been compared for eight successive 5-year periods. A gradual decrease in the severity of referred hypertension and an increase in the proportion of patients already on treatment at the time of referral (currently 50%) were noted. For male patients, mean +/- SD initial lying blood pressure was 179 +/- 27/116 +/- 19 mm Hg in 1950-1954 and 158 +/- 25/91 +/- 14 mm Hg in 1985-1989. Corresponding prevalence data for target organ damage among male patients were retinal grade 3 or 4, 49% and 3%; cardiomegaly on chest radiograph, 60% and 26%; electrocardiogram left ventricle strain pattern, 28% and 3%; and serum urea levels greater than 10 mmol/L, 16% and 5%, respectively. For women there was a similar trend. The number of patients on drugs in each of nine categories and the percent use of each drug category for each year during 1950-1989 was recovered from computerized data files. The percentage peak usage of ganglion blockers was in 1950-1958, adrenergic neuron blockers in 1963-1970, centrally acting drugs in 1965-1968, diuretics in 1960-1982, beta-blockers in 1974-1987, alpha-blockers in 1980-1987, and angiotensin converting enzyme inhibitors and calcium antagonists in 1989. The diuretics have been the most enduring drugs, followed by the beta-blockers.
Subject(s)
Hypertension/physiopathology , Ambulatory Care Facilities , Antihypertensive Agents/therapeutic use , Blood Pressure/physiology , Female , Humans , Hypertension/drug therapy , Hypertension/etiology , Male , Middle Aged , New Zealand , Sex FactorsABSTRACT
The data for patients referred to the Dunedin Hypertension Clinic (975 men, 1,348 women) between 1953 and 1977 have been examined by the Cox proportional hazards method for significant age-corrected predictors of 8-year cardiovascular and total mortality. For men, some significant predictors were systolic and diastolic blood pressure (BP), indices of target organ damage (heart and eyes) and smoking at presentation, and achieved BP and serum cholesterol at follow-up. For women, serum cholesterol, diabetes, target organ damage (heart and eyes) and smoking at presentation, and achieved BP level at follow-up were predictors. Relative risk for total or cardiovascular mortality was increased in both sexes most by smoking and by increased levels of achieved BP.
Subject(s)
Cardiovascular Diseases/etiology , Hypertension/complications , Blood Pressure/physiology , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/mortality , Female , Humans , Hypertension/drug therapy , Male , Models, Biological , New Zealand , Risk Factors , Sex Factors , Smoking/adverse effectsABSTRACT
The xenon-133 method for measuring renal blood flow in the intact rat was evaluated by direct measurement using a nonhemolyzing pump to perfuse kidneys in situ with the rat's own blood. Flows were calculated from the xenon data by means of four commonly used types of analysis: compartmental analysis using the weighted arithmetic mean (WAM), compartmental analysis using the weighted harmonic mean (WHM), stochastic analysis (SA), and initial slope analysis (ISA). WHM and SA estimate actual blood flows, whereas WAM and ISA provide only an index of mean renal flow. All results correlated well with the pumped flows (r values ranged from 0.79 to 0.98). However, the various types of analysis gave a wide range of calculated flows. This may explain some of the variation found in mean renal flow values reported in the literature. The method of choice was WHM, using only the first two compartments; the regression line between this (y) and direct measurement (x) was y = 0.98x + 0.17, r = 0.96.
Subject(s)
Renal Circulation , Animals , Male , Mathematics , Models, Biological , Radioisotope Dilution Technique , Rats , Regression Analysis , Xenon RadioisotopesABSTRACT
Distribution of intrarenal blood flow has been measured in genetically hypertensive (GH) and normotensive (N) rats (aged 17--23 weeks) by a 133Xe washout technique without opening the abdominal cavity. Three different specific flow compartments were found in the rats. The distribution of the intrarenal blood flow to the fast compartment was reduced in the GH rats when compared with the N rats and the rate of flow in it was also reduced. The flow rate in the second compartment was the same in the two strains, the distribution to it being relatively greater in the GH rats. The mean renal blood flow index (in ml/min/g of kidney) was reduced in the GH rats. It is not at present clear whether these differences are due to the hypertension or represent a causative factor in the hypertension.
Subject(s)
Hypertension/pathology , Kidney/blood supply , Animals , Hypertension/genetics , Hypertension/physiopathology , Kidney/physiopathology , Rats , Rats, Inbred Strains , Regional Blood FlowABSTRACT
A method is described for measuring distribution of intrarenal blood flow in anesthetized rats by a xenon-133 washout technique that avoids the trauma of opening the abdominal cavity and manipulating the kidney. Precise delivery of the tracer to the kidney and fine collimation of the radiation reduces the amount of tracer required. Washout curve analysis is achieved by a multifit computer program that accepts only count rates and time as input data.
