Search PubMed⌕ Search

Biomedical subjects

P Kramer

Publications and source records attributed to P Kramer.

At least 163 records · Page 9Linked to original sources
PubMed1982

Retardation of first ovulation in pubertal rats after treatment with 5 alpha-androstane-3 alpha, 17 beta-diol or its 3 beta-epimer.

The effect was studied of five daily injections of 50 microgram of either 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-androstanediol) or its 3 beta-epimer (3 beta-androstanediol), starting on day 22 of life, on sexual maturation in female rats. No difference was found in the age and body weight at first oestrus between oil-treated rats and rats treated with either 3 alpha- or 3 beta-androstanediol. The only difference observed between these groups consisted of the occurrence of a "pinhole" vaginal opening a few days before oestrus in 50% of the steroid-treated rats; in oil-treated rats immediate full vaginal opening and first oestrus coincided in ten out of 12 rats. Different effects were obtained when the higher dose of 100 microgram daily was used; effects were dissimilar in rats treated with 3 alpha- and 3 beta-androstanediol. If administration of the higher dose of 3 beta-androstanediol was started on day 22 and continued until the day of full vaginal opening and first oestrus, a significant delay of this first oestrus, preceded by a few days of a "pinhole" type of vaginal opening was observed. After administration of the higher dose of 3 alpha-androstanediol a "pinhole" type of vaginal opening, accompanied by dioestrous-like vaginal smears, was also found, but oestrus did not occur during the period when injections were given. After the injections were stopped on day 45, first oestrus developed within 6 days in all rats. The previous findings of others that administration of 3 beta-androstanediol to the immature female rat may induce precocious puberty (i.e. precocious vaginal opening and first ovulation) were not confirmed in the present study. Out results indicate that high doses of free 3 alpha-androstanediol, and to a lesser degree 3 beta-androstanediol, may even delay first ovulation in the rat. A possible interference of 3 alpha-androstanediol with the triggering of the first ovulatory gonadotrophin peaks is discussed.

Androstane-3,17-diol↗
PubMed1982

Possible role of 5 alpha-androstane-3 alpha, 17 beta-diol in the control of follicle-stimulating hormone secretion in the immature female rat.

A possible role of 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-androstanediol) in the control of FSH secretion was studied at various ages in ovariectomized rats. In the rat strain used, vaginal opening, coincident with first ovulation, generally occurs between 37 and 42 days of age. If 3 alpha-androstanediol alone was given as an ovarian substitute, an inhibitory effect on FSH release was evident with all three doses tested (50, 100, 300 microgram/100 g body wt) between 13 and 30 days of age; at 33-35 days of age only the 300 microgram dose caused some inhibition of FSH release. Results were more complex if 3 alpha-androstanediol was given in combined treatment with oestradiol and progesterone. Given with progesterone, 3 alpha-androstanediol showed a synergistic inhibitory action on FSH release between 20 and 30 days of age. However, when 3 alpha-androstanediol was combined with oestradiol a clear decrease in effect, as compared to the effect of oestradiol alone, was found between 20 and 30 days of age. Also the effect of combined oestradiol and progesterone treatment was greater than the effect of combined treatment with oestradiol, progesterone and 3 alpha-androstanediol. At all ages after day 20 none of the steroid combinations tested was capable of maintaining FSH levels in ovariectomized rats similar to those in intact rats. It is concluded that 3 alpha-androstanediol might play a role in the control of FSH secretion in the immature rat, but after day 20 the potentially inhibitory action of 3 alpha androstanediol on FSH secretion is limited in the presence of oestradiol.

Androstane-3,17-diol↗
PubMed1982

Ovarian follicular development leading to first ovulation and accompanying gonadotrophin levels as studied in the unilaterally ovariectomized rat.

Ovarian follicular development was studied in the rat during a 15-day period preceding first ovulation. Ovaries were obtained by unilateral ovariectomy performed at various ages and the rats were allowed to live until the day after first ovulation. The timing of this ovulation was compared with that in unoperated, paired control rats of the same age. For estimation of gonadotrophin levels, blood was taken from the paired control rats at the time when experimental rats were unilaterally ovariectomized. There was no evidence that unilateral ovariectomy had any influence on the timing of first ovulation. Therefore the ovaries obtained could be dated in relation to first ovulation, and follicular growth during the final prepubertal period could thus be studied in a genuine developmental sequence. Results revealed that follicular growth leading to first ovulation starts at +/- 8 days before this ovulation; follicular processes taking place are comparable to those found during the adult 5-day cycle but proceed more slowly. Gonadotrophin concentrations accompanying the follicular dynamics and measured at 11.00 h, showed a clear tendency for FSH concentrations to decrease with increasing age, i.e. approaching first ovulation. Concentrations of LH did not show a definite pattern and were generally low, although in some individual rats relatively high LH values ( greater than 100 micrograms/l) were found in the period of 5-3 days before first ovulation.

Animals↗
PubMed1982

Plasma digoxin concentrations during administration of dietary fibre (guar gum) in man.

The effect of guar gum on digoxin absorption was investigated in eleven healthy volunteers. The drug was administered in the morning during two five-day-periods, together with a liquid mixed test meal (+/- 18 g guar). By measuring plasma digoxin concentrations no differences were registered between the control and guar gum period. It is concluded that long-term administration of guar gum will not interfere with adequate digitalization (digoxin bioavailability).

Administration, Oral↗
PubMed1982

Effects of theophylline on behavioral state development in the newborn rabbit.

On Day 1 of life (Day 0 = birth), the sleep-wake behavioral states of rabbits were measured for 2 hr, after which half the animals received 10 mg/kg of theophylline by intubation (N = 16), whereas the remainder received normal saline (N = 17). Behavioral states were then measured on Days 2, 3, 5, 7, 15, 20, 30 and 40. Theophylline sharply reduced active sleep starting on Day 2 and continuing through Day 20. The development of quiet sleep was delayed for 10 days in the drug-treated group. Paralleling the loss of active sleep was a major increase in wake between Days 2 to 20. The drug also affected the intermediate states of sleep-wake transition and active-quiet sleep transition. The data raise major questions about the safety of a drug widely used in the newborn intensive care setting.

Aging↗
PubMed1982

Dialysis treatment and psoriasis in Europe.

One hundred and fifty out of 944 European dialysis centers reported experience with patients suffering from psoriasis. Ninety-three centers returned special questionnaires on 97 patients with end stage renal failure (ESRF patients) and on 49 patients dialyzed for psoriasis but who had normal renal function (NRF patients). Improvement of skin disease was reported in 17 out of 27 NRF patients according to both "objective criteria" and the patients' personal opinions. However, most of these patients had been on dialysis for less than one year (9.9 +/- 11.1 months) which is too short to allow for the spontaneous recurrence of psoriasis. In contrast, 60% of ESRF patients had been on dialysis for 45 +/- 3.1 months. Skin disease definitely improved in 20% of these patients after commencement of dialysis. This proportion is greater than the expected spontaneous long-term remission of psoriasis.

Adult↗
PubMed1982

[Continuous arteriovenous hemofiltration (CAVH)].

The continuous arteriovenous haemofiltration (CAVH) is a simple, safe, inexpensive and personnel-saving method for treatment of uremic patients. Since the introduction of the CAVH in 1977, far more than 200 patients have been treated by this method in our hospital. In the present paper the method and our experiences during the clinical application are presented. The haemofilter is placed in an extracorporal shunt between the A. and V. femoralis. Cannulation of these vessels is performed by means of a modified Seldinger technique using commercially available catheter. During haemofiltration, heparin is infused into the arterial blood line at a rate of 10 IU/kg . h. The filtrate is totally or partially replaced by nutrition solutions, enteral or parenteral, and by a potassium-free Ringer's lactate i.v. solution, according to the required fluid balance. In most cases the filtrate-substitution rate will be high enough to compensate renal failure, and thus conventional dialysis methods will not be necessary. Clinical experience to date allows the following conclusions: optimal control of water and electrolyte balance; unlimited parenteral nutrition, continuous fluid withdrawal better tolerated than intermittent withdrawal by means of dialysis; low risk of local bleeding with skilled puncture technique of the femoral vessels. Low dose continuous heparin administration into arterial blood line is sufficient for extracorporal anticoagulation. Saving of expenses: No investment costs for machines; specially trained dialysis personnel superfluous.

Blood↗
PubMed1981

Role of progesterone in the control of secretion of follicle-stimulating hormone in the immature female rat.

The inhibitory action of FSH secretion of combined oestradiol and progesterone treatment of ovariectomized, immature rat was studied at various ages. At all ages studied (13-35 days) as additional inhibitory action of progesterone, if combined with oestradiol, could be found as compared with the effect of oestradiol alone. Until 20 days of age, the rise in serum FSH concentration as measured 2 days after ovariectomy could be completely prevented by administration of 0.05 microgram oestradiol/100 g body weight or by administration of a lower dose of oestradiol (0.01-0.025 microgram) combined with progesterone (0.5-1.5 mg/100 g body weight). After 20 days neither oestradiol nor the combined oestradiol/progesterone treatment resulted in an FSH concentration similar to that found in intact rats. However, the lowest FSH concentrations were reached by using combinations of oestradiol and progesterone. Using progesterone alone, FSH concentration in ovariectomized rats was significantly reduced between 18 and 30 days of age, but not before or after this period. Taken together with data on uterine weight and serum concentrations of progesterone, these findings suggest that (1) both oestradiol and progesterone exert an age-dependent role in regulating FSH secretion in the immature female rat, and (2) amounts of oestradiol and progesterone capable of maintaining, in ovariectomized rats, uterine weights not different from those in intact rats will maintain near-physiological concentrations of FSH before but not after day 20. Thus, ovarian factors other than oestradiol and progesterone must be involved in the regulation of FSH secretion in the female after 20 days of age.

Animals↗
PubMed1981

Continuous arteriovenous haemofiltration. A new kidney replacement therapy.

Twenty intensive care patients, who as an additional complication developed acute oliguric renal failure were treated solely with continuous arteriovenous haemofiltration (CAVH). The mean spontaneous filtration rate was 8.8 +/- 3.5ml/min. IV substitution of the ultrafiltrate by K+-free Ringer's lactate solution resulted in a steady state plasma creatinine level of 6.4 +/- 3.5mg/dl. Duration of treatment was three to 24 days (10.5 +/- 7.9 days). Eight patients recovered kidney function and survived. Clinical experience in five intensive care units with more than 150 applications of CAVH allows the following conclusions: optimal control of water and electrolyte balance; unlimited parenteral nutrition; continuous fluid withdrawal better tolerated than intermittent withdrawal by means of dialysis. With skilled puncture of the femoral artery there was no risk of bleeding. Low dose continuous heparin administration (10IU/kg/hr) into the arterial blood line is sufficient for extracorporeal anticoagulation. Haemofilters can be used for a long time (two to ten days). Specially trained dialysis personnel and investment costs for machines are not necessary.

Acute Kidney Injury↗
PubMed1981

Colonic gas distribution in toxic megacolon.

To determine whether dilation of the transverse colon is a specific pathophysiologic feature in toxic megacolon, plain films of the abdomen in different positions were obtained of 6 patients with ulcerative colitis complicated by toxic megacolon. All patients were examined initially in the supine position and subsequently in the prone position. Redistribution of gas in the colon occurred in all patients when the prone position was assumed. The shift of gas was largely from the transverse colon to the descending colon. Pathological examination of the colon in 5 patients revealed the transverse colon to be no more severely involved than the remainder of the colon. The findings suggest that distribution of colonic gas in toxic megacolon is largely governed by the influence of gravity and the anatomic position of the colon in the peritoneal cavity.

Adult↗
PubMed1980

[Reno-cardiac interactions in kidney failure (author's transl)].

The high incidence of cardiac complications in endstage renal failure is not only related to the chronic pressure load of the left ventricle, although the proportion of patients with elevated blood pressure increases from 53 to 81% as reno-parenchymal disease progresses. Other factors as anemia, hyperparathyroidism, autonomic neuropathy and retention of electrolytes, metabolic products of toxins may cause damage to the heart. It is a matter of discussion whether uremia itself causes cardiomyopathy. Findings of a reduced Ca++-uptake during beta-adrenergic stimulation and a reduced reaction of (Na+, K+)-ATPase to digitalis suggest a basic change of myocardial membrane metabolism. Retention of an "endogenous digitalis" could help to explain some contradictory results.

Adolescent↗