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Biomedical subjects

V H James

Publications and source records attributed to V H James.

At least 109 records · Page 6Linked to original sources
PubMed1981

Water and electrolyte composition of urine and ileal fluid and its relationship to renin and aldosterone during dietary sodium deprivation in patients with ileostomies.

1. The electrolyte and water composition of urine and ileal fluid was studied in six patients with ileostomies during dietary sodium deprivation and at the same time measurements were made of plasma renin activity, plasma aldosterone concentration, renal aldosterone excretion and plasma arginine vasopressin concentration. 2. In each subject there was a reduction in renal sodium excretion within 24 h of sodium deprivation. Significant rises in plasma renin activity, plasma aldosterone concentration and renal aldosterone excretion occurred by day 2 of sodium deprivation. 3. There was only modest conservation of sodium by the ileum during sodium deprivation, but ileal potassium concentration rose progressively. There were significant associations between ileal-fluid potassium concentration and plasma renin activity or renal aldosterone excretion. 4. Under the conditions of the experiment a diuresis was observed in each subject during dietary sodium deprivation. This did not appear to depend on changes in plasma arginine vasopressin concentration.

Adult↗
PubMed1981

Associations between sex hormones, thyroid hormones and lipoproteins.

1. A study of 150 middle-aged male industrial employees has shown significant positive correlations between plasma levels of high-density-lipoprotein (HDL) cholesterol and both serum testosterone and alcohol intake, and significant negative correlations between HDL cholesterol and both serum thyroxine and obesity. These associations persist when examined by multiple linear regression, indicating their independence. 2. Significant positive correlations are also shown between plasma triglyceride levels and both obesity and serum thyrotropic hormone (TSH) levels. 3. There are no evident relationships between serum oestrone or oestradiol and either HDL cholesterol or triglyceride levels, nor between any of the hormones and either total or low-density-lipoprotein (LDL) cholesterol. 4. Because of the potential importance in relation to coronary heart disease prevention, further studies are needed to try and understand the mechanisms of the associations between HDL cholesterol and obesity, alcohol intake and thyroid and sex hormone levels.

Alcohol Drinking↗
PubMed1981

Studies of diurnal changes in plasma renin activity, and plasma noradrenaline, aldosterone and cortisol concentrations in man.

Diurnal studies were performed on ten normal volunteers taking a normal sodium diet. Half-hourly blood samples were taken throughout 25 h and assayed for plasma renin activity (PRA) and the plasma concentrations of noradrenaline, aldosterone and cortisol. Sleep was recorded polygraphically and scored by standard criteria. Circadian rhythms were demonstrated for plasma cortisol, aldosterone and noradrenaline concentrations, but not for plasma renin activity. The nadir of the rhythm for the noradrenaline concentration appeared to be related to sleep itself rather than to any chronological index. Only PRA was effected by the stage of sleep, falling sharply during periods of REM sleep. Plasma cortisol and aldosterone concentrations showed a positive correlation over the 24 h. There was, however, no correlation between PRA and plasma aldosterone concentrations, except when the subjects arose after their night's recumbency. Plasma noradrenaline concentration did not correlate with the concentration of any of the other hormones measured.

Adult↗
PubMed1981

Abnormal suppression of plasma cortisol during the intravenous infusion of dexamethasone to alcoholic patients.

In some cases the oral administration of dexamethasone to alcoholic patients has failed to cause a normal depression of plasma cortisol levels. Although alcoholics often show signs of intestinal malabsorption, the possibility that the dexamethasone was not fully absorbed has not previously been considered. To eliminate any question of malabsorption, ten male alcoholic patients were infused intravenously with dexamethasone (1 mg/h). The plasma cortisol levels in blood samples withdrawn at half-hourly intervals during a 2-h infusion were compared with the values found in ten normal subjects similarly infused. Four of the alcoholics failed to show normal suppression of plasma cortisol levels, thus confirming that in some alcoholics there is a disturbance of pituitary-adrenal function similar to that found in Cushing's disease. In only one of the four cases was failure to suppress normally associated with the presence of clinical signs of Cushing's disease.

Adult↗
PubMed1981

Fluoroimmunoassay of progesterone in human serum or plasma.

We describe a fluoroimmunoassay for progesterone in serum or plasma. The assay involves use of an antiserum to progesterone-11-hemisuccinate and a labeled antigen prepared by linking fluoresceinamine to progesterone-3-carboxymethyloxime by use of a mixed-anhydride procedure. Serum or plasma samples are extracted with hexane. After incubation of a portion of the evaporated extract with antiserum and labeled antigen, antibody-bound and free antigen are separated and the fluorescence of the bound fraction is measured. Separation is effected either by using ammonium sulfate to precipitate liquid-phase antiserum or by using a solid-phase antiserum: antiserum covalently linked to magnetizable cellulose particles, which are separated with a magnet. With either separation technique, analytical recovery, linearity, and precision were acceptable and results compared satisfactorily with those obtained with a conventional radioimmunoassay. The solid-phase assay is more precise and more technically convenient, but the performance of both fluoroimmunoassays was adequate for clinical use in the detection of ovulation.

Female↗
PubMed1980

Long term spironolactone and the adrenal cortex in essential hypertension.

In view of recent evidence that spironolactone may inhibit synthesis of corticosteroids by a direct effect on the adrenal cortex, adrenocortical function was studied in eight patients with essential hypertension who had been treated with spironolactone from 3 months to 14 years. Their 24 h renal excretion of adrenocorticoid metabolites and the responses of cortisol, aldosterone and 18-hydroxy-11 -deoxycorticosterone (18-OH-DOC) to an incremental infusion of tetracosactrin (1-24 ACTH) were compared with those in eight patients with recently diagnosed essential hypertension who had received no spironolactone. The spironolactone-treated group had a significantly higher excretion of aldosterone, whilst the excretion of other adrenocorticoid metabolites did not differ. The same group also required less tetracosactrin to stimulate a detectable rise of plasma cortisol and 18-OH-DOC, they had greater plasma 18-OH-DOC responses at all infusion rates and, at the lowest infusion rates, had greater aldosterone responses. These results indicate that long-term spironolactone therapy does not inhibit adrenocortical function and may have some stimulatory effects.

18-Hydroxydesoxycorticosterone↗
PubMed1980

Rectally administered prednisolone--evidence for a predominantly local action.

Plasma prednisolone levels have been compared in healthy volunteers and in patients suffering from idiopathic proctocolitis after the administration of standard retention enemata containing either prednisolone-21-phosphate or prednisolone metasulphobenzoate sodium. The levels were significantly lower after the latter, irrespective of the presence or degree of activity of the disease. Prednisolone metasulphobenzoate appeared to be as effective as the 21-phosphate ester for the treatment of proctocolitis in the few patients where the two drugs were compared. It seems possible that the beneficial effect of the form of therapy is exerted predominantly locally, rather than by systemic action.

Colitis↗
PubMed1980

A relationship between plasma renin activity and the rapid eye movement phase of sleep in man.

The possible influence of the central nervous system on renin release was investigated by simultaneously monitoring the PRA and the changes of the sleep-wake cycle. Nine normal volunteers were studied, 2 of whom were subjected to an acute sleep reversal procedure. PRA exhibited marked intra- and intersubject variability. No consistent diurnal or ultradian rhythm was observed. The nocturnal variation in PRA, however, was associated with changes in the stage of sleep. The rapid eye movement (REM) phase correlated with a decrease in PRA. In the 9 subjects, 26 measurements were made during REM, all but 2 of which showed a drop compared to the level obtained in the immediately preceding sleep stage (P less than 0.001), by two-tailed t test). The mean decrease in PRA accompanying REM was 407 pg/ml.h, and the mean time for PRA to decrease by half after REM onset was 33 min, with a SE of 8 min. The sleep reversal procedure confirmed that REM was associated with decreased PRA even when sleep occurred at an unaccustomed time. REM is demonstrated by these findings to be temporally associated with a suppression of PRA. The rate of decrease of PRA after REM onset closely approximates the most recent estimations of PRA half-life, which suggests that REM onset is associated with a virtual cessation in renin production.

Adult↗
PubMed1979

The effect of food and tablet formulation on plasma prednisolone levels following administration of enteric-coated tablets.

1 Plasma prednisolone levels have been compared following the administration of enteric-coated prednisolone to fasted and non-fasted subjects. The effect on plasma levels of altering the formulation of the enteric-coating has also been studied. 2 The presence of food in the stomach at the time of administration does not affect the absorption of enteric-coated prednisolone tablets. 3 There was considerable inter-subject variation in plasma prednisolone levels after administration of shellac based enteric-coated tablets. However, plasma levels were more consistent when a preparation whose formulation was based upon cellulose acetate phthalate (CAP) was given. 4 It is concluded that the pattern of absorption and plasma prednisolone levels depend on the formulation of the enteric coating. The bioavailability of the CAP based preparation is similar to that of plain prednisolone.

Adult↗
PubMed1979

Relation between the karyopyknotic index and plasma oestrogen concentrations after the menopause.

The karyopyknotic index correlated significantly (p less than 0.001) with the plasma oestradiol but not plasma oestrone concentration in 38 postmenopausal women. This ties with previous findings that postmenopausal women with superficial dyspareunia have a more severe degree of vaginal atrophy than asymptomatic women, and that oestradiol is probably more important biologically than oestrone.

Aged↗
PubMed1979

Plasma prednisolone levels and adrenocortical responsiveness after administration of prednisolone-21-phosphate as a retention enema.

Plasma prednisolone levels have been measured by radioimmunoassay after oral and rectal administration to healthy volunteers and to patients with idiopathic proctocolitis. The amount of prednisolone absorbed from a 20 mg retention enema given to patients with proctocolitis was about 44% of that absorbed from the same dose orally administered. Adrenocortical response to synthetic ACTH in patients receiving prolonged rectal therapy was either normal, or only slightly impaired, and this may be related to the pattern of steroid absorption rather than to the total amount absorbed.

Adolescent↗