Asunto(s)

RESUMEN

Plasma clearance rates and dialysance of labelled cortisol were measured in patients on chronic intermittent dialysis during and after dialysis. Plasma clearance rates during dialysis were 30--63% higher than after dialysis; dialysance was 0.3--0.7 1/h and accounted only for 20--35% of the increase of plasma clearance rates during dialysis. After bolus injection of labelled cortisol, disappearance curves were obtained in two normal subjects and two uraemic subjects on and off dialysis. Biological halftimes of the different segments of the disappearance curves and distribution volumes were calculated. The size of the inner compartment (V1) is greater in uraemia. The disappearance curves flatten after the end of dialysis, indicating an increase of biological halftime after dialysis. Plasma 17-OHCS-glucuronides dropped from 2.13 +/- 0.62 micromol/l (n = 20) at the beginning to 1.05 +/- 0.65 micromol/l at the end of dialysis and increased to 1.51 +/- 0.43 micromol/l (n = 12) within 3 h thereafter. During dialysis cortisol metabolites are removed from the blood. This may decrease inhibition of cortisol metabolism by the end products of cortisol metabolism which might explain the more rapid plasma clearance and the shortened cortisol half-life during haemodialysis.

Asunto(s)

RESUMEN

Plasma cortisol levels in 2 normal persons, 2 obese persons, 2 uraemic patients, and 2 patients with cirrhosis of the liver were raised in 4 steps by a combination of iv priming doses and continuous infusions of cortisol. Plasma cortisol levels and transcortin binding were measured as well as plasma clearance rates of labelled and unlabelled cortisol during each of the 5 experimental periods. Plasma cortisol levels increased less and plasma clearance rates of labelled and unlabelled cortisol increased more in obese persons than in normal persons; in patients with disturbed metabolism of cortisol (uraemia, cirrhosis of the liver) the reverse is true. Plasma clearance rates of free cortisol were calculated and differed from an estimated hepatic plasma flow of 0.7 1/min under certain conditions. Since free cortisol is metabolized faster than transcortin-bound cortisol, increasing plasma clearance rates of cortisol are probably due to increasing ratios free/bound cortisol when total plasma cortisol levels are raised. Low plasma clearance rates of cortisol in uraemia and cirrhosis of the liver are thought to be due to endproduct inhibition, respectively reduced liver cell mass.

Asunto(s)

RESUMEN

Aldosterone excretion (AE) and plasma renin activity (PRA) were measured in eight untrained (UT) and eight endurance-trained (TR) male subjects before and during 4 h head-out immersion to study the mechanism of reduced renal sodium excretion in athletes. AE was significantly lower before immersion, and decreased less during immersion, in TR than in UT. Fractional sodium excretion, too, was lower and increased less during immersion in TR than in UT. PRA decreased in the water bath in all subjects (p less than 0.001) with no significant difference between the groups. During immersion, plasma sodium concentration oscillated whereas potassium concentration showed a temporary rise in TR (p less than 0.001). The attenuated response of AE in TR may be due partly to this increase of plasma potassium concentration. The generally reduced aldosterone release in TR might be caused by a training induced adaptation of the adrenals to corticotropin. The lowered renal sodium excretion of TR in spite of the decreased AE suggests an intensified aldosterone effect in these subjects, diminishing the salt loss during exercise.

Asunto(s)

Asunto(s)

RESUMEN

In a retrospective study the following was found: Out of 111 patients suffering from tuberculosis and receiving a combined INH-therapy without Rifampicin 23% showed an increase of serum-transmainase activities, on the other hand out of 105 patients, treated with a combination including Rifampicin 74% did so. A pathological De Ritis ratio GOT/GPT was found in 31 among 59 comparable cases of Rifampicin-treated patients, and a pathological ratio GOT + GPT/AP in 22 among 37 cases before the transaminase-activities rose above normal. Development of a distinct toxic hepatic damage has to be anticipated in those cases, which show a De Ritis ratio below 0,5 or a GOT + GPT/AP ratio above 1,0 while transaminase-activity still is only slightly elevated. Liver biopsies taken from 10 patients showed no regular relation to the biochemical data.

Asunto(s)

RESUMEN

The effects of 4--6 h head-out immersion on excretion of vanillylmandelic acid (VMA), blood pressure and plasma volume were estimated in 8 endurance-trained (TR) and 8 untrained (UT) subjects. In the trained only a slight increase of VMA excretion occurred (4 h value: +2.7 +/- 10.9 ng/ml GFR), but there was a highly significant increase in the UT (+29.0 +/- 17.2 ng/ml GFR). VMA values during control experiments in supine position tended to decrease in both groups. Systolic and diastolic blood pressure fell by 20 mm Hg after beginning of immersion; in the UT plasma volume was reduced while it remained constant in TR. The results indicate that orthostatic intolerance (o.i.) after immersion is not effected by decreased sympathetic innervation of vessels; in contrast it seems to be partly compensated for by an elevated sympathetic activity at least in the UT. As a main cause for the post-immersion o.i. one might suggest a decrease in renin activity.

Asunto(s)

Asunto(s)

RESUMEN

Radio-immunological estimation of free cortisol in urine in a group of normal persons showed a median daily excretion of 42,5 +/- 22,8 mug (n = 31) using radio-loss-labelling, extraction, and thin layer chromatography. After simple extraction the median value was 54.1 +/- 15.3 mug/d (n = 10). Radioimmunological estimation in simple urine extract seems to be sufficient for routine clinical purposes. The estimation of free cortisol in urine permits a better differentiation between normal adrenal function and adrenal hyperactivity than the determination of 17-hydroxycorticosteroids (17-OHCS). This is shown by comparison of 1) the frequency distribution of the basal values of 17-OHCS and free cortisol in normal persons and in Cushing's disease, 2) the suppression effect of dexamethasone on 17-OHCS and free cortisol in Cushing patients, and 3) the stimulatory effect of ACTH on 17-OHCS and free cortisol in normal persons.

Asunto(s)

RESUMEN

The excretion of creatinine, VMA, and aldosterone was measured in the urine of 14 normal and 25 persons with stable essential hypertension during a day time (7.00-23.00 hrs) and a night time (23.00-7.00 hrs) period. Excretion of VMA and aldosterone per hour in the two groups was lower during the night period than during the day. No significant difference existed between the excretion values of both groups. Night/day rations for the excretion of VMA and of aldosterone respectively, per mg of creatinine excreted were calculated for each subject. In the normal group the night/day ratios of aldosterone excretion showed a significant correlation to the corresponding ratios of VMA excretion; such correlation was not found in the hypertensive group. The fact that a correlation was observed in the normal group is compatible with the hypothesis that catecholamines are involved in the regulation of the renin-angiotensin-aldosterone system. Lack of correlation in the group of hypertensive does not as yet allow any conclusions. In two patients with primary hyperaldosteronism, the aldosterone excretion during the night was relatively more elevated than in the day.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)