The anti-hypertensive effect of potassium loading in experimental hypertension: a comparison of sheep with other species.

The anti-hypertensive effect of potassium (K) loading in human essential hypertension and several types of experimental hypertension is well established. However, the mechanism of the anti-hypertensive effect is not understood. The natriuretic effect of a high K intake has lead many to conclude that the blood pressure lowering effect of K may be mediated through enhanced sodium (Na) excretion leading to negative Na status.

The effect of potassium loading on sodium status and pressor responsiveness in the sheep.

The effect of increased potassium (K) intake (800 mmol/day) was investigated in conscious sheep to elucidate the mechanism of the anti-hypertensive effect of K loading. Mean arterial pressure rose (4mm Hg, n = 13, p less than 0.001).

Medullary sponge kidney and congenital hemihypertrophy.

We have presented a case of medullary sponge kidney associated with congenital hemihypertrophy. Evaluation by calcium loading revealed no abnormal handling of this ion. The recognition of this unusual syndrome is important because it appears that other disease processes common to medullary sponge kidney alone or congenital hemihypertrophy alone do not appear with the same frequency when both processes occur simultaneously.

Immunochemotherapy of bladder carcinoma with glucan and cyclophosphamide.

Recent evidence suggests a role for both immunotherapy and chemotherapy in the treatment of transitional cell carcinoma. Glucan, a derivative of the cell wall of Saccharomyces cerevisiae and a potent immunostimulant, was used in combination with cyclophosphamide for treatment of implanted murine transitional cell carcinoma (MBT 2). Cyclophosphamide prevented tumor appearance when tumor burden was low and decreased tumor growth rate in larger tumor volumes, but was unable to eradicate established tumors.

When is serum albumin worth measuring?

This paper critically examines the usefulness of serum albumin measurement in the light of current laboratory practice and knowledge of the pathophysiology of albumin metabolism. The main conclusions and recommendations are as follows: (i) Albumin measurement forms a limited, but useful part of the investigation of liver disease; a normal serum albumin concentration makes the diagnosis of cirrhosis unlikely, while a low level in viral hepatitis suggests either severe hepatocellular damage or other complications. (ii) Albumin measurement is essential in selecting patients for, and in determining the amount and frequency of, albumin replacement.

Blood pressure and metabolic effects of 18-oxo-cortisol in sheep.

18-Oxo-cortisol (18-oxo-F) has been isolated from the urine of subjects with primary aldosteronism. This study examines the pressor, mineralocorticoid and glucocorticoid effects of 18-oxo-F in conscious sheep--a well studied species for the assessment of the pressor effect of steroid hormones. 18-oxo-F (24 mg/day i.

Role of the autonomic nervous system, renin-angiotensin system, and arginine vasopressin during the onset and maintenance of ACTH hypertension in sheep.

The roles of the autonomic nervous system, renin-angiotensin system, and arginine vasopressin (AVP) during the onset of ACTH-induced hypertension were investigated in conscious sheep. Autonomic ganglion blockade or combined adrenergic and cholinergic receptor blockade demonstrated that an intact sympathetic nervous system was not essential for the development or maintenance of the hypertension. Autonomic blockade augmented the pressor response to ACTH, indicating that baroreceptor-mediated reflexes normally operate to suppress the degree of hypertension produced by ACTH.

The haemodynamic effects of cyclosporin A in sheep.

1. Cyclosporin A (CyA; 12 mg/kg/day) was infused into six conscious sheep over 5 days to examine the haemodynamic effects of the drug in normal animals. 2.

Ultrasound detection of bilateral Leydig cell tumors in palpable normal testes.

We report a case of synchronous, nonpalpable, bilateral Leydig cell tumors that were detected only by ultrasound evaluation and gonadal vein sampling for estradiol. A review of the diagnostic and management options for Leydig cell tumors is presented.

Impact of routine screening for adenocarcinoma of the prostate on stage distribution.

The impact of routine screening with digital rectal examination for carcinoma of the prostate on stage distribution of the disease was assessed in the primary treatment population of our medical center. Two, 5-year periods were compared: 1974 to 1978--before the onset of routine screening and 1979 to 1983--during the period of routine screening of this population. The clinical stage distribution of prostatic cancer before the onset of routine screening was not significantly different from national averages.

Serum protein zone electrophoresis--an outmoded test?

The predictive value of plasma protein changes in disease is very largely unknown, as relevant clinical and laboratory studies are lacking. The usefulness of zone electrophoresis as a method of detecting a constellation of plasma protein changes is even less clear. With the advent of precise automated techniques for specific plasma protein measurement, zone electrophoresis has little to offer except in the identification and quantitation of paraproteins, where it is essential.

Structure-activity relationships for blood pressure effects of prednisolone in sheep.

This study investigated the effect of 5 day infusions of 6 alpha and 9 alpha-fluoro and 16 alpha, 17 alpha-acetal analogues of prednisolone on blood pressure in conscious sheep. In vivo mineralocorticoid (MC) and glucocorticoid (GC) activities of these steroids were also measured. Prednisolone (100 mg/d) produced a small increase in mean arterial pressure associated with increased fasting plasma [glucose] and polyuria, but had no MC activity.

Modification of the haemodynamic effects of ACTH by angiotensin II in sheep.

The study was performed to examine the hypothesis that adrenocorticotrophic hormone (ACTH) induced hypertension in sheep would be enhanced if the blood level of angiotensin II (ANG II), normally suppressed during ACTH administration, was kept at control levels by intravenous infusion of ANG II. Administration of ACTH at 1.0 microgram/kg/day for 6 days produced a half maximum rise in mean arterial pressure, delta 14 mmHg, associated with hypokalaemia and initial urinary sodium retention.

Steroid antagonism of the hypertensinogenic activity of adrenocortical steroids.

Previous studies in sheep have provided evidence for a separate "hypertensinogenic" class of adrenocortical steroid activity which is not simply related to their classical mineralocorticoid (MC) and/or glucocorticoid (GC) actions. This study investigated the structure-activity relationships of the effects of structural analogues of prednisolone on mean arterial pressure (MAP), and MC and GC actions in sheep. Infusions of these synthetic GC at 0.

The effect of sodium depletion and potassium loading on cortisol induced hypertension in sheep.

Glucocorticoid induced hypertension has been regarded as independent of sodium (Na), in contrast to mineralocorticoid induced hypertension, which is Na+-dependent. These studies compare the effect of Na+ depletion and potassium (K+) loading on glucocorticoid hypertension induced by cortisol in conscious sheep. Cortisol (480 mg/d) for 5 days, in sheep on a normal chaff diet (90-140 mmol/d Na+, 200-250 mmol/d K+) increased mean arterial pressure by 18 mmHg on day 5, increased plasma Na+ concentration, reduced plasma K+ concentration, and did not change urinary Na+ excretion.

The effect of nivazol and cortivazol, novel synthetic steroids containing a phenylpyrazolo A-ring substitution, on blood pressure in sheep.

This study investigated the effect of 5 day infusions of two structurally novel synthetic steroids, nivazol and cortivazol on blood pressure and in vivo indices of "glucocorticoid" and "mineralocorticoid" activity. Cortivazol at 24 mg/day raised mean arterial pressure (MAP) by 16 mmHg (P less than 0.001).

The effect of the 'hypertensinogenic' steroid, 9 alpha-fluorocortisol on blood pressure in sheep with ACTH-induced hypertension.

The effect of treatment with 9 alpha-fluorocortisol (9 alpha FF), a steroid which causes hypertension in sheep, was examined in sheep with ACTH-induced hypertension. ACTH treatment alone increased mean arterial pressure (MAP), plasma Na concentration, water intake and urine volume and decreased plasma K concentration. 9 alpha FF treatment, for 3 days during continuing ACTH administration, did not change blood pressure but increased heart rate, water intake and urine volume and decreased urinary K excretion.

Effect of 1,3-butanediol and short chain acids in sow gestation diets on maternal plasma metabolites and fetal energy storage.

Gestating sows were fed diets in which 15% of the metabolizable energy was in the form of glucose monohydrate (control), 1,3-butanediol (BD) or an equimolar mixture of acetate and lactate (AL) in order to study the effects of ketogenic, glucogenic and lipogenic substrates on fetal energy storage. Diets were initiated on d 90 of gestation. Blood plasma was obtained from sows 2 and 8 h after feeding on d 102 of gestation.

Angiotensin converting enzyme inhibition does not prevent development of ACTH-induced hypertension in sheep.

The role of the renin-angiotensin system in the onset of ACTH-induced hypertension was examined in five conscious sheep. Captopril infusion alone (15 mg/kg per day) for 2 days produced a small fall in blood pressure. After 2 days of captopril ACTH was infused (20 micrograms/kg per day) for 3 days together with captopril.

Serotonergic mechanisms and blood pressure in sheep.

This study examined the effects of the serotonergic (5-HT2) antagonist ketanserin in sheep on haemodynamic responses to infused serotonin (5-HT), development of adrenocorticotrophin (ACTH)-induced hypertension, and the effect of ACTH on in vivo pressor responsiveness to 5-HT. Serotonin produced a dose-related increase in mean arterial pressure and heart rate. These increases in mean arterial pressure were attenuated or abolished by ketanserin, but increases in heart rate were enhanced.

Steroid antagonism of the 'hypertensinogenic' activity of 9 alpha-fluoroprednisolone.

We have previously reported that adrenocortical steroids raise blood pressure by a 'hypertensinogenic' mechanism of action which is not simply related to their classical 'mineralocorticoid' or 'glucocorticoid' actions. This study presents evidence for specific antagonism of this 'hypertensinogenic' activity. The effects of separate IV infusions of prednisolone (P) 100 mg/d and 9 alpha-fluoro-prednisolone (9 alpha F-P) 0.