Search PubMed⌕ Search

Biomedical subjects

A Ulmann

Publications and source records attributed to A Ulmann.

At least 73 records · Page 4Linked to original sources
PubMed1986

Antiprogesterone activity of RU 486 and its contragestive and other applications.

RU 486 is the first antiprogesterone to be used clinically. It inhibits the action of the hormone at the receptor level in target tissues. Its action is particularly significant in the endometrium where it prevents the initiation and progression of pregnancy in the first weeks (contragestive effect). The data indicate that the compound can be used for: voluntary interruption of pregnancy between 6 and 10 weeks; induction of menstruation during the fifth week of amenorrhoea, and post-coital contraception. Current trials include its use as a once-a-month menses inducer. It can also be utilized for therapeutic interruption at a late stage of pregnancy, and tried as adjuvant treatment in some cases of breast cancer. The data on RU 486 have been obtained through studies in physio-pharmacological endocrinology and biochemistry. The development of this antihormone represents a concerted research link between biology and medicine.

Abortifacient Agents↗
PubMed1985

Kinetic analysis of lactate dehydrogenase in cultured chondrocytes by quantitative cytochemistry.

Kinetic analysis of lactate dehydrogenase activity in intact cultured chondrocytes was performed in situ by coupling cell culture and microcytophotometry. Cells were cultured on glass microscope slides divided into eight chambers and studied during the growth cycle in monolayer areas. Lactate dehydrogenase activity was assayed by the reduction of neotetrazolium in the presence of phenazine methosulfate. Quantification of formazan deposits within the cells was performed by scanning and integrating microdensitometry at the isosbestic wavelength of 585 nm. Results indicate the following (a) A kinetic characterization was possible: apparent constants, Km and Ks of this two-substrate enzyme were graphically determined Ks = 1.05 +/- 0.08 and 0.56 +/- 0.05 mM for lactate and NAD respectively and Km = 0.64 +/- 0.03 and 0.37 +/- 0.02 mM for lactate and NAD respectively. (b) Inhibition by lactate concentrations above 10 mM and pyruvate concentration of 1 mM, is in agreement with the well known high anaerobic glycolytic metabolism of chondrocytes. This was confirmed by electrophoresis on cellulose acetate which demonstrated a M3-H isoenzyme form in cultured chick chondrocytes. This study shows that microcytophotometric analysis of lactate dehydrogenase in cultured chondrocytes may be an interesting alternative to mass culture cells followed by classical biochemical studies.

Animals↗
PubMed1985

(Na-K)ATPase activity along the nephrons in normal and adrenalectomized rats measured by quantitative cytochemistry.

A cytochemical method was used to measure total, ouabain insensitive and specific (Na-K)ATPase activities along the rat nephron. Enzyme activity was expressed as per cent of mean integrated extinction with reference to a calibrated filter. The lowest mean values of total, ouabain-insensitive, and (Na-K)ATPase activities were found in the proximal convoluted tubule (PCT). In the distal convoluted tubule (DCT), total and ouabain-insensitive activities (77.8 per cent and 45.8 per cent, respectively) were significantly higher than in the medullary thick ascending limb (MAL) (66.0 per cent and 24.6 per cent, respectively). Mean values of (Na-K)ATPase activity were significantly lower in DCT than in MAL (32.0 per cent and 41.3 per cent, respectively). Using Lineweaver-Burk plots, the KM ATP value for total ATPase activity was found to be 2.33, 1.79, and 3.63 mM in DCT, MAL, and PCT respectively. Maximal velocity was lower in PCT than in MAL and DCT. For (Na-K)ATPase, the smallest KM value was found in MAL (0.95 mM) and was 2.73 and 5.71 mM in DCT and PCT respectively. Maximal velocity was the highest in MAL (49.3 per cent), lower in DCT (36.1 per cent) and least in PCT (22.5 per cent). ATPase was measured in the MAL and DCT from rats fed a normal (N-Na+) or a high (Hi-Na+) sodium diet, and from Hi-Na+ rats one week after adrenalectomy (ADX). In the MAL, (Na-K)ATPase tended to be higher in Hi-Na+ than in rats, but was significantly lower in ADX than in Hi-Na+.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1985

Assessment of the antimineralocorticoid effect of RU 28318 in healthy men with induced exogenous and endogenous hypermineralocorticism.

The antimineralocorticoid effect of a single dose of RU 28318, has been assessed in healthy men with exogenous or endogenous hypermineralocorticism. For exogenous hypermineralocorticism induced by ingestion of 9 alpha-fluorohydrocortisone (9 alpha-FHC) and aldosterone infusion, RU 28318 100 mg (9 alpha-FHC ingestion) or 200 mg (aldosterone infusion) was administered, and its effect compared with identical doses of spironolactone or a placebo. For endogenous hypermineralocorticism induced by ingestion of furosemide, RU 28318 100 and 300 mg was tested in comparison with 100 mg spironolactone or placebo. In all 3 studies, both RU 28318 and spironolactone significantly raised the urinary Na/K ratio when compared to placebo administration. No significant difference was apparent between RU 28318 and spironolactone. Thus, a single dose of RU 28318 in man has an antimineralocorticoid effect identical to those produced by the identical molar dose of spironolactone. In addition, the results show that furosemide-induced hyperaldosteronism constitutes a simple and reproducible test for assessing the antimineralocorticoid effect of a drug.

Adult↗
PubMed1985

Phosphate fluxes in isolated enterocytes from vitamin D replete and vitamin D deficient rats--early effects of calcitriol.

In the present work we studied rapid in vitro effects of calcitriol (1,25(OH)2 vitamin D3) on the intestinal transport of inorganic phosphate (Pi). Enterocytes from vitamin D replete (D+) as well as vitamin D depleted (D-) rats were isolated mechanically from the duodeno-jejunum. In this model, Pi uptake was a temperature and Na+-dependent phenomenon. The in vitro-addition of calcitriol (1 pM) resulted in a significant enhancement of initial Pi uptake rate by enterocytes from D+ (P less than 0.01) and D- (P less than 0.05) rats. This effect which was Na+-dependent, was observed within the time of 20 min, but not before. A similar effect on Pi uptake rates of D+ or D- enterocytes could be elicited by the in vitro addition of the methyl ester of cis-vaccinic acid (MCVA) which is thought to increase membrane fluidity by modifying the lipid composition of the cell membrane. The stimulatory effect of calcitriol on Pi uptake rate was blunted in the presence of the methyl ester of transvaccinic acid (MTVA) thought to decrease membrane fluidity. Enterocyte Pi efflux rate constant (oKPi) remained unchanged in the presence of calcitriol (1 pM). In conclusion, the study demonstrates a rapid in vitro effect of calcitriol on Pi uptake by isolated enterocytes from D+ and D- rats. It suggests, but does not prove, that the hormone may act via an action independent of genomic nuclear activation.

Animals↗
PubMed1985

Hypercalciuria during experimental vitamin K deficiency in the rat.

Vitamin K promotes the formation of gamma-carboxylated glutamate (GLA) in several protein species. GLA residues have a high affinity for the Ca ion. In the present study, we tested the hypothesis that experimental vitamin K deficiency in rats could induce changes in Ca metabolism. Vitamin K depletion, which was associated with a reduction in urinary GLA excretion, induced within 7 days a significant increase in cumulative urinary Ca excretion that persisted throughout the 21 days of study. The hypercalciuria of vitamin K-deficient rats was corrected on vitamin K supplementation. No concomitant changes were observed in intestinal Ca absorption determined by a balance technic or of skeletal resorption and apposition rates determined by bone histomorphometry. Plasma Ca, but not total protein concentration, of vitamin k-depleted rats showed a transient decrease at day 15 that disappeared at day 21. plasma sodium, phosphate and 1,25(OH)2 vitamin D concentration, and urinary phosphate, sodium, and creatinine excretion remained unchanged. In conclusion, vitamin k deficiency in the rat induced hypercalciuria that could be of renal origin. Its possible relationship to vitamin K-dependent renal GLA protein remains to be clarified.

1-Carboxyglutamic Acid↗
PubMed1985

[Recklinghausen's disease with hypophosphoremia and osteomalacia. Apropos of 2 cases].

The authors report two cases of osteomalacia due to phosphate diabetes in patients with Recklinghausen's disease. In one case abnormalities of vitamin D metabolism were identical with those described in cases of phosphate diabetes associated with mesenchymal tumours. The abnormalities found in the second case were different. The physiopathological mechanism of osteomalacia due to phosphate diabetes in mesenchymal diseases generally and in Recklinghausen's disease in particular is discussed.

Adult↗
PubMed1985

Effect of plasma levels of parathyroid hormone on NADPH pathways in kidney and liver.

NADPH available for mixed function oxidations (pathway 1) or biosynthetic processes (pathway 2) has been evaluated in different cells from rat liver and kidney. In addition, changes of the proportion of NADPH utilized in each pathway were demonstrated in the same cells from rats showing different circulating levels of parathyroid hormone (PTH). Quantitative levels of NADPH directed into each of these pathways have been measured and histologically located in sections from rat liver and kidney using quantitative cytochemistry and scanning and integrating microdensitometry. Centrilobular hepatocytes utilize the major amount of NADPH, either via pathway 1 or 2. Kidney cells utilize most NADPH via pathway 2, particularly in the distal part of the nephron. The cells of the pars recta have shown the highest capacity to utilize NADPH via pathway 1, which is about half that of centrilobular hepatocytes. In centrilobular cells, the presence of high plasma levels of PTH results in a significant increment of NADPH utilization either via pathway 1 or 2. In kidneys from rats showing high plasma levels of PTH, a selective increase in NADPH utilized via pathway 2 was observed in the distal convoluted tubule whereas a selective increase in NADPH utilized via pathway 1 was demonstrated in cells of the pars recta. These observations provide further information in the understanding of the physiology of kidney and liver cells.

Animals↗
PubMed1985

Early effects of vitamin D metabolites on phosphate fluxes in isolated rat enterocytes.

The present studies were designed to explore the possibility that, in addition to its well-known steroidlike action, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the active vitamin D3 metabolite, modulates inorganic phosphate (Pi) transport across the intestinal mucosa through more rapid membrane effects. Enterocytes were mechanically isolated from the duodenojejunum of vitamin D-replete rats. In this model enterocyte Pi uptake was a temperature-dependent as well as a Na+-dependent process. In vitro addition of 1,25(OH)2D3 (1 pM) led to a significant increase in Na+-dependent initial Pi uptake velocity (iVpi) within 20 min (P less than 0.001). No effect was seen for shorter incubation times (5 and 15 min). Incubation of the cells with cycloheximide did not inhibit the hormone-mediated increase of iVpi. 25-Hydroxyvitamin D3 significantly increased iVPi (P less than 0.05) at a concentration of 1 nM but not 1 pM. Vitamin D3 at a concentration of 1 microM had no effect on iVPi. Enterocyte Pi efflux rate constant was not modified by the presence of 1,25(OH)2D3(1pM). Thus, the early in vitro effect of 1,25(OH)2D3 on Pi uptake by isolated enterocytes suggests a nongenomic action of the hormone, possibly by modifying the lipid structure of the plasma membrane.

Animals↗
PubMed1985

Renal magnesium and phosphate wastage in a patient with hypercalciuria and nephrocalcinosis: effect of oral phosphorus and magnesium supplements.

We report a 29-year-old man with a mild decrease in glomerular filtration, nephrocalcinosis, hypercalciuria and a renal magnesium leak. He had other features of 'congenital magnesium-losing kidney', such as arthritis and hyperuricemia, short stature and recurrent urinary tract infections, but had no radiological chondrocalcinosis. In addition, pallidal calcification was found. The patient also had a renal phosphate leak. Phosphorus supplements resulted in a decrease in urinary calcium excretion, indicating that hypercalciuria was at least partially a consequence of phosphorus depletion. Plasma and urine magnesium were not affected by phosphorus supplements. Addition of magnesium supplements resulted in a transient and modest decrease in urinary calcium excretion, with no modification in plasma magnesium.

Administration, Oral↗
PubMed1985

Clinical and histological resolution of systemic amyloidosis after renal cell carcinoma removal.

This report describes the case of a 62-year-old woman with systemic amyloidosis involving the kidneys and digestive tract, consecutive to a renal cell carcinoma. Within 3 years after tumor removal, both the nephrotic syndrome and protein loss enteropathy regressed. Histological examination showed the disappearance of the potassium permanganate-sensitive deposits within the digestive tract. This indicates that clinical remission of systemic amyloidosis may be associated with morphologic disappearance of amyloid deposits.

Amyloidosis↗
PubMed1985

Elevated metabolic clearance rate of 1 alpha,25-dihydroxyvitamin D3 in hyperthyroidism.

Metabolic clearance rate (MCR) and daily production rate (DPR) of 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) were measured in 7 hyperthyroid patients and 8 control subjects after a single injection of tritiated 1,25(OH)2D3. Using a bicompartmental analysis, MCR of 1,25(OH)2D3 was found to be significantly higher in hyperthyroid than in control subjects (11.5 +/- 4.4 vs 5.9 +/- 2.4 ml/min (SD), P less than 0.01). No significant difference in plasma 1,25(OH)2D and DPR of 1,25(OH)2D3 was demonstrated. MCR was again measured 1 month after initiation of treatment in 4 hyperthyroid patients and remained elevated. In 2 of these patients, MCR was once more determined 6 months later and had declined towards normal. No correlation was found between MCR and DPR and either plasma calcium, phosphate, immunoreactive PTH, 1,25(OH)D and T3 values. In conclusion, MCR of 1,25(OH)2D3 is elevated in hyperthyroidism, but this finding is probably unrelated to the effect of thyroid hormones on bone metabolism.

Adult↗
PubMed1985

Does vitamin K excess induce ectopic calcifications in hemodialysis patients?

Vitamin K promotes the formation of gamma-carboxylated glutamic acid (Gla) residues within different protein classes such as vitamin K-dependent clotting factors, bone Gla-protein (BGP or osteocalcin), and atherocalcin. Gla-containing proteins have a high affinity for the Ca2+ ion. In addition to bone and atheromatous plaques they are also regularly found in ectopic calcifications, but not in uncalcified soft tissue. In the present study we investigate the possibility that vitamin K and BGP, in addition to previously recognized factors, may play a role in soft tissue calcification of chronic hemodialysis patients. Patients without radiovisible ectopic calcifications (group A) are compared to patients with such Ca deposits (group B). Both patient groups have comparable values of predialysis plasma Ca, P, alkaline phosphatases, parathyroid hormone (PTH) and 25 hydroxyvitamin D. The CaxP product is slightly higher in group B than in group A patients. Plasma vitamin K1 levels of group B patients are increased to more than twice the values observed in group A patients. Plasma BGP, even though not significantly different, shows a trend towards decreased levels in group B patients. A positive correlation exists between plasma vitamin K1 and BGP for patient group A alone, but not for group B alone. A correlation is also observed between plasma PTH and BGP (all patients) and between serum alkaline phosphatases and plasma BGP (all patients). Taken together, these results favor the hypothesis that in addition to an increased CaxP product a vitamin K excess may induce soft tissue calcification in hemodialysis patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Aldosterone antagonists: hypotensive and natriuretic drugs].

Antimineralocorticoid drugs are widely prescribed as hypertensive agents, with an efficacy comparable to other drugs (thiazide diuretics, beta-blockers), especially in low-renin hypertension. However they require a prolonged lag-time (several weeks) in order to obtain maximal hypotensive effect. There is no hypokalemia and its possible cardiac and metabolic consequences. They are sometimes responsible for dose-dependent sexual side effect. Knowing the pathophysiology of these effects as well as the precise renal and extra-renal mechanism of action of antimineralocorticoids should lead to the discovery of new specific, efficient and safe compounds for which there is need in the management of hypertension.

Humans↗