Angiotensin II attenuates the natriuresis of water immersion in humans.

The hypothesis was tested that suppression of generation of ANG II is one of the mechanisms of the water immersion (WI)-induced natriuresis in humans. In one protocol, eight healthy young males were subjected to 3 h of 1) WI (WI + placebo), 2) WI combined with ANG II infusion of 0.5 ng.

Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease.

High individuality causes laboratory reference ranges to be insensitive to changes in test results that are significant for the individual. We undertook a longitudinal study of variation in thyroid function tests in 16 healthy men with monthly sampling for 12 months using standard procedures. We measured serum T(4), T(3), free T(4) index, and TSH.

Normal responses of atrial natriuretic factor and renal tubular function to sodium loading in hypertension-prone humans.

Background: In order to explore the hypothesis of an atrial natriuretic factor (ANF) deficiency in prehypertension, we compared the response to sodium loading on ANF and renal function in subjects with positive and negative histories of hypertension.

Methods: Twenty-two offspring of hypertensive parents (OH) and 20 offspring of normotensive parents (ON) were studied after 4 days of low (50 mmol/day) or high (300 mmol/day) dietary sodium intake. The diets were allocated randomly.

Renal effects of hyperinsulinaemia in subjects with two hypertensive parents.

The aim of this investigation was to study the effects of isoglycaemic hyperinsulinaemia on the renal metabolism of electrolytes and water in subjects with a strong genetic predisposition to essential hypertension, compared with that in non-predisposed subjects. We studied 25 normotensive subjects aged 18-35 years whose parents both had essential hypertension, and 22 age- and sex-matched subjects whose parents were both normotensive. Diabetes or morbid obesity in any subject or parent excluded the family.

Insulin resistance, exercise capacity and body composition in subjects with two hypertensive parents.

Objective: To study insulin resistance in subjects with strong genetic predisposition to essential hypertension, compared with non-disposed subjects.

Subjects: Thirty normotensive subjects aged 18-35 years whose parents both had essential hypertension, and 30 age- and sex matched subjects whose parents were both normotensive, were studied. Subjects or parents with diabetes and morbid obesity were excluded.

Low back pain and lifestyle. Part II--Obesity. Information from a population-based sample of 29,424 twin subjects.

Study Design: A cross-sectional postal survey of 29,424 twin subjects aged 12-41 years obtained from a population-generated panel.

Objectives: To determine whether obesity is associated with low back pain.

Summary Of Background Data: Despite a large number of epidemiologic studies in this area, it is unclear whether obesity and low back pain are positively associated, and if so, whether there is a causal association.

Low back pain and lifestyle. Part I: Smoking. Information from a population-based sample of 29,424 twins.

Study Design: A cross-sectional postal survey of 29,424 people aged 12-41 years obtained from a population-generated panel of twin individuals.

Objectives: To study whether smoking causes low back pain.

Summary Of Background Data: Despite insufficient evidence in the epidemiologic literature, it has become increasingly accepted that smoking causes low back pain and that discontinuation of smoking is a suitable means of secondary prevention.

Radioimmunoassay of endothelin in human plasma.

A specific and sensitive radioimmunoassay (RIA) for determination of endothelin-1 (ET-1) in human plasma has been developed. Antibodies were raised in rabbits using synthetic ET-1 conjugated to thyroglobulin as immunogen. The antibodies obtained were used at a final dilution of 1:300,000 yielding maximum binding of 61.

Renal sites of action of physiological increases in plasma atrial natriuretic factor concentration in essential hypertension.

Objectives: To investigate the renal, haemodynamic and neurohormonal responses to low-dose infusions of atrial natriuretic factor (ANF) in hypertensive humans.

Design: Ten patients with mild-to-moderate essential hypertension received incremental infusions of 3 and 6 ng/kg per min ANF or vehicle alone whilst on a constant dietary sodium intake. A 90-min basal clearance period was followed by two 2-h infusion periods, with urine collection in the last 90 min of each period.

Effects of hyperglycaemia on kidney function, atrial natriuretic factor and plasma renin in patients with insulin-dependent diabetes mellitus.

In normoalbuminuric patients with insulin-dependent diabetes mellitus, plasma atrial natriuretic factor (ANF), cyclic GMP and active renin and the renal clearances of [99Tcm]-diethylenetriaminepentaacetic acid (DTPA) lithium and sodium were studied on a hyperglycaemia day and a euglycaemia day. Baseline euglycaemia was achieved by an overnight variable insulin infusion, which during study days was fixed at the rate necessary to maintain euglycaemia in the morning. After a baseline euglycaemic clearance period of 90 min, measurements were repeated in a new 90-min period beginning 150 min later.

Comparison of different standards used in radioimmunoassay for atrial natriuretic factor (ANF).

Six different standards for determination of atrial natriuretic factor (ANF) in human plasma samples have been compared using our radio-immunoassay for ANF: International standard 85/669, National Biological Standard Boards, UK; Bachem standard, Torrance, USA; Bachem standard, Bubendorf, Switzerland; Bissendorf standard, Wedemark, Germany; Peninsula standard, Belmont, USA; UCB-Bioproducts standard, Brussels, Belgium. Standard curves obtained with different preparations were in parallel but showed considerable quantitative differences. Standard curves referring to the Bissendorf standard and the International standard, respectively, were almost identical.

Effects of insulin on renal haemodynamics and sodium handling in normal subjects.

Diabetic patients treated with insulin injected subcutaneously are characterized by peripheral hyperinsulinaemia and an increased mass of total body exchangeable sodium. We hypothesized that this may cause, at least in part, the glomerular hyperfiltration seen in the diabetic state. Six normal subjects were studied on 2 days in random order.

Effect of insulin on renal sodium handling in hyperinsulinaemic type 2 (non-insulin-dependent) diabetic patients with peripheral insulin resistance.

The sodium retaining effect of insulin was studied in ten Type 2 (non-insulin-dependent) diabetic patients (mean age 56 (43-73) years, mean body mass index 29.5 (24.2-33.

Unchanged extraction of atrial natriuretic factor across the chronic ischemic human kidney.

The extractions of atrial natriuretic factor (EANF) and the glomerular filtration marker 51Cr-ethylenediamine tetraacetic acid (EEDTA) were determined before and after intravenous injection of furosemide across each of the two kidneys during renal vein catheterization in hypertensive patients with unilateral or bilateral renovascular disease. Before administration of furosemide, EANF was approximately 55% across both the more and the less affected kidney while EEDTA was significantly decreased across the more affected kidney. Significant lateralization of renin secretion to the more affected kidney was found, demonstrating an enhanced ipsilateral formation of renin.

Renal and endocrine effects of physiological variations of atrial natriuretic factor in normal humans.

The renal and endocrine effects of incremental infusions of 3 and 6 ng.kg-1.min-1 of exogenous atrial natriuretic factor (ANF)-(99-126) or placebo were investigated in 10 normal subjects.

Enhanced fractional sodium reabsorption in the ischaemic kidney revisited with lithium as a probe.

Extraction of lithium and 51Cr-EDTA across each of the two kidneys was determined during renal vein catheterization in 14 hypertensive patients with unilateral or bilateral renovascular disease before and after i.v. injection of furosemide.

Normal renal tubular response to changes of sodium intake in hypertensive man.

In a comparative study the influence of changes in dietary sodium intake on blood pressure, renal function, extracellular fluid volume, the renin-angiotensin-aldosterone system and plasma concentrations of arginine vasopressin, atrial natriuretic factor and cyclic guanosine monophosphate (GMP) was investigated in 12 patients with essential hypertension and in 10 normotensive controls. The subjects were studied after 4 days on a low (50 mmol/day), medium (180 mmol/day) or high (380 mmol/day) sodium intake. Renal sodium handling was assessed by simultaneous measurements of 51Cr-ethylenediaminetetraacetic acid (EDTA), lithium and sodium clearances.

[Calcium antagonists: an antihypertensive alternative].

From a pathophysiological point of view, antihypertensive therapy with a vasodilator is rational. However, since traditional vasodilators, such as hydralazine, may cause retention of sodium and water, tachycardia and excessive stimulation of the renin-angiotensin-aldosterone system, they are not suitable for monotherapy. The Ca-antagonists include a number of drugs with quite different chemical structures.

The acute effect of acetazolamide on glomerular filtration rate and proximal tubular reabsorption of sodium and water in normal man.

The acute effects on kidney function of acetazolamide (250 mg) given intravenously were evaluated in seven healthy subjects. Glomerular filtration rate was measured as the renal clearance of 51Cr-EDTA, and fluid flow rate out of the proximal tubules was assessed by measurement of the renal lithium clearance. An 18% decline in glomerular filtration rate (ml/min) was observed after acetazolamide administration (109 +/- 16 vs 89 +/- 14, p less than 0.

Effects of insulin on kidney function and sodium excretion in healthy subjects.

Insulin action on kidney function was evaluated in 8 healthy subjects, (mean age 27 years) using the euglycaemic clamp technique. Insulin was infused at rates of 0, 20 and 40 mU.min-1.

The increased proximal tubular reabsorption of sodium and water is maintained in long-term insulin-dependent diabetics with early nephropathy.

Proximal tubular reabsorption of sodium and water was investigated in long-term insulin-dependent diabetic patients with normoalbuminuria (group I, n = 19), microalbuminuria (group II, n = 39), diabetic nephropathy (group III, n = 12) and in 13 healthy age-matched subjects. Glomerular filtration rate was measured with the single injection, 51Cr-EDTA technique. The fluid flow rate out of the proximal tubules was assessed by the renal lithium clearance.

Interobserver agreement and accuracy of bedside estimation of right and left ventricular ejection fraction in acute myocardial infarction.

Ninety-eight patients with acute myocardial infarction were examined by 3 clinicians who, independently of each other, gave an estimate of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) in each patient. Their estimates were based on physical examination, chest x-ray, electrocardiogram, patient history and clinical course during admission. Ejection fractions were estimated as belonging to 1 of 4 categories: normal (LVEF greater than or equal to 0.

Unchanged lithium clearance during acute amiloride treatment in sodium-depleted man.

To evaluate the validity of the lithium clearance method as a marker of overall proximal tubular fluid delivery in moderately sodium-depleted humans, the effects of a single dose of 10 mg amiloride on lithium clearance and glomerular filtration-rate were studied in normal volunteers maintained on a sodium diet of 50 mmol/day. Amiloride caused no changes of the glomerular filtration-rate or of lithium clearance. The effects of amiloride on tubular sodium, potassium and water handling were in accordance with a distal tubular action of amiloride.