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Biomedical subjects

H Mathieu

Publications and source records attributed to H Mathieu.

At least 91 records · Page 5Linked to original sources
PubMed1985

[Molecular approach to the action of vitamin D in man].

Some applications to man of specific markers of the molecular action of vitamin D (1.25(OH)2D3 receptors and antibodies to hormone-dependent proteins (CaBP and cDNA] are reported in this study. On case of type II vitamin-dependent rickets was characterized by 1.25(OH)2D3 plasma level greater than 250 pg/ml and a ten-fold decrease of the number of binding sites of the hormone in cultured skin fibroblasts. We propose that CaBP 28K and/or 9K-containing cells, such as Purkinje's cells and chondroblasts may be targets for vitamin D action. Detection in fetuses, from the 20th week of gestation, of CaBP 9K messenger RNA in the duodenum and sternum and presence of CaBP 28K and 9K in the chondroblasts of the upper extremity of tibia, suggest that vitamin D acts on the nucleus of its target-cells during fetal development. Finally, discovery of the gene of CaBP 9K in man opens the prospect of studies which will improve the understanding of the mechanism of action of vitamin D.

Adolescent↗
PubMed1984

Hemolytic-uremic syndrome: an analysis of the natural history and prognostic features.

Sixty-seven children with hemolytic-uremic syndrome (HUS) were admitted between 1974 and 1981. Of these, 52 (78%) were aged less than 3 years. All children had acute renal failure and 48 (72%) required peritoneal dialysis. The etiology in twenty cases varied from bacterial and viral infections (7 and 5 cases, respectively) to renal irradiation with chemotherapy (2) and preexisting glomerulopathy (1). 5 (7%) children died during the acute phase of the illness. Long-term follow-up (mean 3 years 3 months) of 56 cases showed that 37 children (60%) had so far experienced no functional sequelae and 8 (13%) only mild sequelae while 3 (5%) were on iterative hemodialysis, 3 had severe chronic renal failure and high blood pressure (HBP) and 5 (8%) had HBP and normal kidney function. While the recovery rate was approximately 60% in all age groups, the mortality rate and serious after-effects were twice as frequent (42%) in children over 3 years of age as in those less than 3. Renal histology (total of 37) showed 12 cases of cortical necrosis, 22 of glomerular thrombotic microangiopathy (TMA) and 3 arterial TMA. Prognosis was poor for all cases of arterial TMA and 58% of those exhibiting cortical necrosis.

Acute Kidney Injury↗
PubMed1984

Lung mechanics in rachitic rats.

Lung mechanics was studied at 50 days of age in 7 rachitic rats born from mothers deprived of vitamin D. They were compared with 7 control rats raised in the same conditions but fed a diet supplemented with vitamin D. The animals were anesthetized, tracheotomized, and paralyzed. Quasi-static pressure-volume curves of the respiratory system and of the lungs were obtained. Body weight of the rachitic rats was within the range of the control rats, but dry lung weight (LW) was significantly lower (p less than 0.01). Lung volumes in absolute terms and when normalized for LW were significantly lower than in the control rats. Chest wall compliance (Ccw) of the rachitic rats was within the range of values of the control rats, except for 2 animals with an infinite Ccw. Analysis of the pressure-volume curves of the lungs of the rachitic rats compared with those in the control animals showed a significant decrease in lung compliance (CL) and in CL/LW (p less than 0.01), indicating a decrease in lung distensibility. The more severe the rickets (according to microradiographic criteria of the tibia), the lower the CL/LW. It is speculated that decrease in lung distensibility may be related to abnormal lung growth caused by disturbed alveolar formation and lung connective tissue development. These abnormalities could be due to vitamin D deficiency acting on the growing lung, as on the growing bones, by a mechanism involving proteoglycans.

Animals↗
PubMed1984

[Influence of amoxicillin combined with clavulanic acid on the fecal flora in children].

The effect of an amoxycillin-clavulanic acid combination on the intestinal bacterial ecosystem was studied by differential quantitative analysis of the fecal flora in 11 hospitalized pediatric patients aged 8 months to 4 years. The antibiotic combination was given orally to 7 patients and intravenously to 4. The modifications in the intestinal flora are more important with oral route than intravenous route. After treatment, an increase in ampicillin-resistant E. coli with overgrowth of Klebsiella were found. Our previous studies have shown that this microbial overgrowth carries a risk of secondary septicemia. A strain of amoxycillin-resistant Serratia marcescens emerged but did not pullulate . The other aerobic or anaerobic bacteria were not significantly modified. Most strains which emerged after therapy remained susceptible to the combination. Yeasts emerged in two patients. Thus, the amoxycillin-clavulanic acid combination results in intestinal Klebsiella overgrowth, requiring monitoring of the intestinal bacterial ecosystem.

Amoxicillin↗
PubMed1984

[Influence of cefoperazone on the fecal flora in children].

A differential quantitative study was used to evaluate the effects of parenteral cefoperazone upon children's fecal flora. Fecal specimens were obtained from 16 patients, before, during and after therapy. Cefoperazone therapy was associated with major changes in fecal flora. There was marked reduction or suppression to undetectable levels of Enterobacteria, Staphylococci and Streptococci in 13 patients. During therapy, yeasts were selected or acquired in 7 cases. 5 to 10 days after cefoperazone was discontinued, the fecal flora was virtually the same as before treatment. Thus, cefoperazone should prove very useful in the treatment of septicemia due to intestinal overgrowth.

Adolescent↗
PubMed1983

Biochemical evidence for the presence of two vitamin D-dependent calcium-binding proteins in mouse kidney.

Mouse kidney, a vitamin D target organ, was investigated for the presence of vitamin D-dependent calcium-binding proteins (CaBP). Mouse kidney cytosol was fractionated by several biochemical methods including gel filtration chromatography, gel permeation high performance liquid chromatography, and chromatofocusing. Mouse kidney was found to possess two CaBPs which completely differed biochemically and exhibited no cross-immunoreactivity. One had a molecular weight of 25,000 and a pI of 5.9. The other, with a molecular weight of 10,000 and a pI of 4.9, was biochemically identical with mouse duodenal 10,000 CaBP. In addition, mouse renal and duodenal 10,000 CaBPs were immunologically identical. Moreover, the 10,000 CaBP was the predominant CaBP in mouse kidney since the latter contained about twice as much 10,000 CaBP as 25,000 CaBP (in mol/mg of renal cytosolic protein). In vitro incorporation of [3H]leucine into renal 10,000 CaBP demonstrated that it is synthesized in situ by mouse kidney. Renal 10,000 CaBP was already present during fetal life, and reached its adult level during the first week after birth. The vitamin D dependency of both mouse renal 10,000 and 25,000 CaBPs was assessed by their decrease in vitamin D-deficient mice and subsequent rise after 1,25-dihydroxyvitamin D3 injection. The concomitant presence of substantial amounts of two vitamin D-dependent CaBPs in mouse kidney is peculiar to this organ, which might consequently provide a unique model for studying the hormonal expressions of 1,25-dihydroxyvitamin D3.

Animals↗
PubMed1983

Gel-permeation high-performance liquid chromatography as a powerful technique for rapid analysis of calcitriol (1,25-dihydroxycholecalciferol) receptors.

We used gel-permeation high-performance liquid chromatography to detect cytosolic and nuclear calcitriol (1,25-dihydroxycholecalciferol) receptors. This new convenient technique allowed accurate separation of the calcitriol receptor from other vitamin D-binding proteins. Compared with sucrose-density-gradient centrifugation, it has several advantages including, in particular, its rapidity.

Animals↗
PubMed1983

In rat uterus 17 beta-estradiol stimulates a calcium-binding protein similar to the duodenal vitamin D-dependent calcium-binding protein.

A calcium-binding protein (CaBP) similar to rat duodenal vitamin D-dependent CaBP was identified in rat uterus. Uterine CaBP and duodenal CaBP had the same mol wt (9,000-10,000), exhibited the same calcium-dependent electrophoretic mobility, and were immunologically identical. The localization of CaBP in the rat uterus was explored using indirect immunoperoxidase methods, and by CaBP RIA in the endometrium and myometrium after enzyme separation. In the endometrium CaBP was found in the cytoplasm of the stroma cells but not in the epithelium or in the glandular cells. In the myometrium, it was located inside the smooth myometrial fibers. Hormonal regulation of CaBP was shown to differ in the uterus and duodenum. Duodenal CaBP concentrations increased in response to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and were not influenced by ovariectomy or sex steroids administration. By contrast, CaBP synthesis fell drastically in the uterus of ovariectomized rats, but was greatly enhanced by low physiological doses of 17 beta-estradiol. This effect of 17 beta-estradiol on uterine CaBP was dose dependent. Medroxyprogesterone and more especially 1,25(OH)2D3 exerted no such stimulating effect on uterine CaBP. In vitamin D-deficient ovariectomized rats, administration of 17 beta-estradiol alone restored the uterine CaBP concentrations to normal and this potency contrasted with the apparent inability of 1,25(OH)2D3 to affect the uterine CaBP concentrations. Our data suggest that, unlike duodenal CaBP regulation, the expression of the CaBP gene in rat uterus is predominantly controlled by 17 beta-estradiol.

Animals↗
PubMed1982

Presence of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 24-hydroxylase in vitamin D target cells of rat yolk sac.

In the pregnant rat, the yolk sac, which possesses true placental functions, is a vitamin D target organ. We tested its ability to hydroxylate 25-hydroxy- and 1,25-dihydroxyvitamin D3 (25-OHD3 and 1,25-(OH)2D3). 24,25-Dihydroxy- and 1,24,25-trihydroxyvitamin D3 were produced by rat yolk sac homogenates incubated with tritiated 25-OHD3 and 1,25-(OH)2D3. Rat yolk sac homogenates also formed small amounts of 25,26-dihydroxyvitamin D3. These newly synthesized metabolites were isolated and identified by Sephadex LH-20 chromatography, high performance liquid chromatography, and periodate cleavage. Yolk sac 25-OHD3- and 1,25-(OH)2D3-24-hydroxylases were present in mitochondria and were of a mixed function oxidase nature. They were detected in the yolk sac as early as day 12 in the embryonic period and until the end of gestation. No hydroxylation occurred in maternal liver, amnion, fetal brain, or skin homogenates. Both 24-hydroxylases were detected in pure isolated rat yolk sac endodermal cells. This may be of physiological importance, since they are the 1,25-(OH)2D3 target cells in the yolk sac. Injection of 1,25-(OH)2[3H]D3 into rat yolk sac vitelline veins strongly suggested that the yolk sac vitelline veins strongly suggested that the yolk sac produced 1,24,25-(OH)3D3 in vivo. We conclude that the yolk sac and more precisely its endodermal cells may help to control vitamin D metabolism within the fetoplacental unit.

Animals↗
PubMed1982

Biochemical characterization of mouse vitamin D-dependent calcium-binding protein. Evidence for its presence in embryonic life.

We compared immunochemical and biochemical properties of the vitamin D-dependent Ca2+-binding protein (CaBP) from rat and mouse intestine. The two intestinal CaBP species were extensively purified by gel filtration and successive anion-exchange chromatographies. Both had a similar mol.wt. of 9000. Their pI values differed markedly, being 8.0 and 4.9 in rat and mouse CaBP respectively. Accordingly, mouse CaBP displayed more anodal migration in electrophoresis under non-denaturing conditions. Both mouse and rat CaBP only exhibited partial immunochemical similarities, but their amino acid compositions were very similar. Chromatofocusing was also found to be a good method of detecting calcium-dependent changes in their pI. We developed a sensitive radioimmunoassay for mouse CaBP enabling us to detect substantial amounts of CaBP in uterus, yolk sac and chorio-allantoic placenta. During normal mouse gestation, CaBP appeared on day 12 in the chorio-allantoic placenta but was already present on day 9 in the yolk sac, where its level rose sharply between days 9.5 and 10. CaBP may therefore be considered as a new marker for mouse yolk-sac differentiation.

Amino Acids↗
PubMed1982

Familial hypoplastic glomerulocystic kidney. A new entity?

Two pairs of female siblings of French and Italian origin presented with the histological picture of glomerulocystic kidneys. The cases differ from the patients previously described with glomerulocystic kidneys by the absence of major extrarenal malformations, the reduction of kidney size with absence of renal papillae and by the presence of stable chronic renal failure, starting during the first months of life. Both mothers of the patients also had chronic renal failure with similar urographic abnormalities.

Biopsy↗
PubMed1981

[Effects of cefotaxime on the intestinal bacterial ecosystem in children (author's transl)].

Cefotaxime activity was studied in pediatric practice on the intestinal bacteria flora of 10 children, by means of a differential quantitative method for aerobic and anaerobic faecal flora and was compared to that of 41 controls not receiving any antibiotics. Cefotaxime was given alone in 7 children, and in combination with gentamicin in 3. An effect on the intestinal bacterial flora was noted on E. coli, which disappeared in 4 cases and diminished considerably in 5. A slight increase in Streptococcus D was observed without excessive multiplication of the flora. The study showed no significant alteration for the other aerobic or anaerobic bacilli. There was no selection of resistant organisms. Cefotaxime is a new cephalosporin which does not seem to produce an increase in many resistant pathogens due to a break-down of the barrier effect observed on the bacterial flora of the gut in children.

Cefotaxime↗
PubMed1981

[Cefotaxime and Gram-negative infections in children. Effectiveness and tolerance (author's transl)].

Twenty-six children, aged from 15 days to 14 years, were treated with cefotaxime. 5 were suffering from septicaemia, 14 from respiratory tract infection and were ventilated (intensive care unit), 4 from urinary tract infection and 3 from otitis media complicated with renal failure (nephrology unit). The choice of cefotaxime treatment was based upon the bacterial activity. The daily dose was 50 to 100 mg/kg by the i.m. route, or by slow intravenous injection every 8 hours. In 17 patients, cefotaxime was combined with an aminoglycoside (gentamicin or amikacin). The results were evaluated on the basis of clinical, radiological and bacteriological criteria and, whenever possible, were correlated to the serum levels of antibiotic. The antibiotic was clinically effective in 25 out of 26 patients. The three deaths that occurred, were due to the nature of the initial disease. Tolerance was good in all the patients studied. The efficacy of cefotaxime correlated well with the favorable in vitro bacteriological results and with serum concentrations. Cefotaxime is well tolerated as shown in newborn babies. Cefotaxime is markedly different from previous cephalosporins, because of its high antibacterial activity on most Gram-negative bacilli.

Adolescent↗