Role of the adrenal cortex in the natriuresis associated with vasopressin infusion.

We have compared the effects of a 48-h continuous infusion of arginine vasopressin (AVP) given to four subjects (one subject studied twice) with that given to four patients lacking adrenocortical function and maintained on fixed doses of mineralocorticoid and glucocorticoid replacement therapy. Both patients and normal subjects were subjected to dietary salt and water restriction during the period of the infusion, and all participants were in balance on a low sodium diet at the start of the infusion period. Infusion of vasopressin in normal subjects was associated with an increase in fractional excretion of sodium by the kidney, which continued during the day after the infusion was stopped. The infusion was also associated with a fall in plasma aldosterone as well as falls in whole blood packed cell volume, plasma renin activity and plasma noradrenaline. Infusion of vasopressin in patients lacking adrenocortical function was associated with a smaller increase in fractional excretion of sodium by the kidney in comparison with that seen in normal subjects, and the increase in sodium excretion was confined to the period of the infusion. Mineralocorticoid activity was maintained constant during the infusion, although a fall in whole blood packed cell volume, plasma renin activity and plasma noradrenaline were noted, in similarity to the study made in normal subjects. We conclude that changes in mineralocorticoid activity are the main factors contributing to the increase in renal sodium excretion seen during, and after, the continuous infusion of vasopressin in salt- and water-restricted man.

Dominantly inherited glomerulonephritis and an unusual skin disease.

An unusual association of uncommon facies including telangiectasia in a butterfly distribution, a similar skin lesion on extensor areas, sparse hair, and membranoproliferative glomerulonephritis is described in a 4 year old boy and his father. The mode of inheritance of these features seems to be autosomal dominant.

Aortic occlusion in systemic lupus erythematosus associated with antiphospholipid antibodies.

The patient, a Caucasian woman of 22 years, developed malignant hypertension at the age of 16 years. An abdominal bruit was found on routine examination. She had two spontaneous abortions and systemic lupus erythematosus was diagnosed at age 21 years. She was found to have a persistently low positive VDRL and antibodies to mitochondria were also present on repeated examinations, to a titre of 1/160. Because of angiographic findings, demonstrating an occlusion of the aorta, an endarterectomy of the descending thoracic and upper abdominal aorta was performed. This showed mainly intimal thickening and the presence of thrombus. She then had four further spontaneous abortions (with good blood pressure control). The lupus anticoagulant and antibodies to cardiolipin were found to be positive at this time.

Controlled trial of calcitriol in hemodialysis patients.

We report on a 5-year, prospective, double-blind trial of 1,25 dihydroxycholecalciferol (calcitriol) versus placebo in 76 hemodialysis patients without biochemical or radiological evidence of bone disease. Calcitriol, 1 microgram daily, regularly induced hypercalcemia. Doses of 0.25 microgram daily or less proved satisfactory in most patients. During calcitriol treatment, plasma calcium concentration was significantly higher and serum parathyroid hormone concentration significantly lower than on placebo. There was no difference in the rates of development or of progression of vascular calcification in the two groups. Significantly more patients on placebo (17 vs. 6, p less than 0.05) developed a sustained elevation of plasma alkaline phosphatase concentration. Calcitriol appeared to protect against the development of histological evidence of osteitis fibrosa but not of osteomalacia, but accumulation of aluminum in bone occurred during the study. We conclude that calcitriol delays and may prevent the development of osteitis fibrosa in patients receiving regular hemodialysis and may reasonably be prescribed routinely in hemodialysis patients without biochemical or radiological abnormality, unless there is a substantial prospect of early renal transplantation.

Progressive proliferative glomerulonephritis in a patient with rheumatoid arthritis treated with D-penicillamine.

A 49 year old man with rheumatoid arthritis developed a proliferative glomerulonephritis with progressive renal impairment during treatment with D-penicillamine. His renal function continued to deteriorate after the drug was stopped but improved after treatment with corticosteroids and azathioprine.

Effect of angiotensin converting-enzyme inhibition on potassium-mediated aldosterone secretion in essential hypertension.

1. Eight patients with essential hypertension were challenged with an infusion of 32 mmol of potassium chloride in saline before and after control of their blood pressure by the angiotensin converting-enzyme (ACE) inhibitor enalapril. 2. The potassium infusion was associated with similar increases in plasma aldosterone before and during enalapril treatment, although absolute aldosterone levels were lower after enalapril treatment despite higher plasma potassium levels. 3. The handling of the potassium load was altered by ACE inhibition. The area under the curve of a plot of the increase in plasma potassium above baseline against time was greater during enalapril treatment than during treatment with placebo. 4. These observations contrast with data obtained in the dog and demonstrate that in patients with essential hypertension stimulation of aldosterone secretion by potassium is not abolished by chronic suppression of plasma angiotensin II; and although plasma aldosterone remains at a lower level, the homoeostasis of plasma potassium is only mildly impaired.

Dihydrocodeine in renal failure: further evidence for an important role of the kidney in the handling of opioid drugs.

The pharmacokinetics of a single oral dose of dihydrocodeine were studied in nine patients with chronic renal failure treated by haemodialysis and nine subjects with normal renal function. In the patients the mean peak plasma dihydrocodeine concentration occurred later and the area under the curve was greater than in the normal subjects. Furthermore, the drug was still detectable after 24 hours in all the patients but only three of the normal subjects. These data, together with those obtained from previously published clinical case reports, contradict the traditional view that the body's ability to cope with opioid drugs is not altered in renal failure.

Alteration of pituitary-thyroid function in patients with chronic renal failure treated by haemodialysis or continuous ambulatory peritoneal dialysis.

Pituitary-thyroid function was investigated in 60 patients with chronic renal failure and 18 normal subjects. Serum triiodothyronine and free thyroxine levels were lower in patients treated by either haemodialysis or continuous ambulatory peritoneal dialysis compared with the normal subjects. Serum thyroxine and free thyroxine index were significantly lower in the haemodialysis-treated patients than in the normal subjects. There were no differences in serum thyroxine and free thyroxine index between the continuous ambulatory peritoneal dialysis-treated and normal groups. Serum thyrotrophin was not raised in any of the groups but the serum thyrotrophin response to thyrotrophin-releasing hormone was blunted in both groups of patients. Basal serum prolactin and growth hormone were raised in both groups of patients but there was no significant difference between them. This study confirmed that pituitary-thyroid function is abnormal in patients receiving haemodialysis and established that a similar pattern of abnormalities occurs in patients undergoing continuous ambulatory peritoneal dialysis.

Effect of dialysate buffer on potassium removal during haemodialysis.

There is a linear relationship between potassium removal during haemodialysis and plasma potassium (Kp). Kp falls rapidly during the first hour of dialysis but very little during the last two hours of a five hour dialysis. There is a fairly constant movement of potassium from the intracellular to extracellular space throughout dialysis. Total potassium removal is best predicted by pre-dialysis Kp, but change in Kp is related to the impact of dialysis on acid-base status. The choice of acetate or bicarbonate buffered dialysate does not effect potassium removal during dialysis.

The effects of a chronic infusion of arginine vasopressin in salt-restricted, water-deprived man.

The effects of a 48 h infusion of arginine vasopressin (AVP) were measured in five separate studies on four normal salt-restricted physicians, in whom fluid retention was prevented. The infusion was associated with an increase in renal sodium excretion which continued during the 24 h after the infusion had been discontinued. During the infusion plasma renin activity (PRA), plasma aldosterone and noradrenaline, and packed cell volume (PCV) fell; glomerular filtration rate, assessed by endogenous creatinine clearance, increased. The findings are best explained by a vasopressin-induced increase in plasma volume, which in the absence of fluid retention is likely to have been due to a redistribution of body water.

Bopindolol: a new long acting beta-receptor antagonist; its effects on haemodynamics, and on the renin response to tilting.

Oral administration of single doses of bopindolol (1-4mg) caused significant reductions in the rises of systolic blood pressure and heart rate produced by exercise; only the reduction in the rise of heart rate was significantly dose-related. Resting heart rate was reduced by bopindolol. There were small effects on resting blood pressure. Bopindolol caused a significant attenuation of the rise in plasma renin activity produced by passive head-up tilting to 75-85 degrees. Bopindolol produced a dose-related attenuation of the increase in pulse rate evoked by passive tilting. All effects 1-4 were maintained for at least 24 h. There was no measurable effect on plasma potassium concentration, peak flow rate or forced expiratory volume (FEV1).

Plasma mercury during prolonged acute renal failure after mercuric chloride ingestion.

Serial measurements of plasma mercury were made in a patient with severe and prolonged acute renal failure due to poisoning with mercuric chloride. An initial mercury concentration in whole blood of 1200 micrograms/l (6 mumol/l) was recorded, and recovery of renal function coincided with a fall in plasma mercury concentration to below 100 micrograms/l (0.5 mumol/l). The case demonstrates that survival and recovery of renal function is possible despite very high concentrations of mercury in the blood and oliguric renal failure of nearly six weeks' duration.

Controlled trial of calcitriol in the prevention of bone disease in haemodialysed patients.

Seventy-six patients receiving regular haemodialysis, without biochemical or radiological evidence of renal osteodystrophy, entered a five-year double-blind placebo-controlled trial of calcitriol (1,25-dihydroxycholecalciferol) in the prevention of bone disease. Significantly more patients on placebo developed bone disease as judged by a sustained elevation of plasma alkaline phosphatase or the development of sub-periosteal erosions on hand radiographs. Serum parathyroid hormone fell significantly in the patients receiving calcitriol and was significantly lower than in patients receiving placebo. It is concluded that calcitriol delays and may prevent the development of metabolic bone disease in patients receiving regular haemodialysis therapy.

The effect of captopril and propranolol on the responses to posture and isometric exercise in patients with essential hypertension.

The effects of captopril and propranolol on blood pressure, heart rate and plasma noradrenaline, renin and aldosterone, and on the responses to changes in posture and to isometric exercise were measured in patients with essential hypertension. During placebo administration blood pressure, heart rate and plasma noradrenaline rose on standing and during isometric exercise. The rise in diastolic blood pressure during isometric exercise correlated significantly with the rise in plasma noradrenaline. During captopril treatment blood pressure was significantly lower than during placebo administration when the patients were lying, standing or sitting, but the reduction during isometric exercise was not significant. Plasma renin increased, but heart rate, plasma noradrenaline and plasma aldosterone remained unchanged. The acute changes in blood pressure, heart rate and plasma noradrenaline produced by standing and isometric exercise during captopril treatment were similar to those during placebo administration. During propranolol treatment diastolic blood pressure was significantly lower than during placebo administration when the patients were lying, standing or sitting and during isometric exercise. Heart rate also fell. Plasma noradrenaline during standing, sitting and isometric exercise was significantly greater than during placebo administration. The changes in plasma noradrenaline measured during propranolol treatment with the patients supine were negatively correlated with noradrenaline values obtained during placebo administration: plasma noradrenaline fell in patients with higher, and increased in those with lower, initial concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)