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Biomedical subjects

D Ménard

Publications and source records attributed to D Ménard.

At least 91 records · Page 5Linked to original sources
PubMed1987

[Comparison of the effect of captopril and minoxidil on left ventricular mass. Results of a 6-month comparative double-blind test].

A randomised double blind study was performed in order to compare the cardiac effects of captopril and minoxidil in a subset of patients with severe primitive hypertension, uncontrolled (diastolic BP greater than 100 mmHg) by Metroprolol 200 mg/d and Furosemide 80 mg/d. 25 male pts completed the six month study, 33 pts having been excluded before randomisation (22 inadequate echoes) and 20 after randomisation (7 ambiguities on wall measurement). Average captopril dosage was 265 mg/d (150-300 mg), average minoxidil dosage was 19.6 mg/d (7.5-30 mg), dosages of Furosemide, Spironolactone and Metroprolol were similar in the two groups. Blood pressure decreased dramatically with both regimens (208/130 to 148/96 with captopril, 194/115 to 154/100 with minoxidil). Sokolow index was at the upper range of normal and decreased with both drugs. Cardiothoracic ratio decreased only with captopril. Echocardiograms were performed and read blindly at the end of the study. LV mass was measured according to Devereux, method. All patients had severe LVH. After 6 months posterior wall thickness decreased from 14.8 to 13.8 mm with captopril, remained stable from 14.1 to 14.9 mm with minoxidil, septal thickness decreased from 17.2 to 15.7 mm with captopril and remained stable (14.8 to 15.2 mm) with minoxidil. LV mass and mass index respectively decreased from 456 g and 232 g/m2 to 372 g and 190 g/m2 with captopril, and remained unchanged from 413 g and 215 g/m2 to 420 g and 218 g/m2 with minoxidil. Fractional shortening remained normal in both groups. Intra patients reproducibility was suboptimal because of difficulties in precise delineation of the endocardium in the severely hypertrophied ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Double-blind evaluation of slow-release nicardipine using different methods of blood pressure measurement. Predictive value of the acute response to intravenous nicardipine].

Forty hypertensive patients (diastolic greater than 95 mmHg) were included after 15 days of a single blind placebo period in a randomized placebo controlled double-blind study to assess the antihypertensive effect of a new galenic form of nicardipine (N) administered 50 mg b.i.d. for 3 weeks. They comprised 27 men and 13 women aged from 27 to 72 years (mean: 53 +/- 10). Blood pressure (BP) was measured in hospital before morning drug intake by an automatic recorder (Sentron) in supine position for 30 minutes (min) and by a mercury sphygmomanometer. Ambulatory BP was assessed by a portable patient activated recorder (Remler 2000). Mercury sphygmomanometer supine BP under N fell from 160 +/- 21/104 +/- 6 mmHg to 151 +/- 14/98 +/- 8 mmHg (n = 20; p less than 0.01/p less than 0.01) whereas BP under placebo (P) was respectively 158 +/- 14/103 +/- 6 mmHg and 156 +/- 20/102 +/- 9 mmHg (NS). Sentron BP under N fell from 158 +/- 17/96 +/- 8 mmHg to 148 +/- 13/90 +/- 7 mmHg (p less than 0.001/p less than 0.01) with no BP change under P (152 +/- 12/93 +/- 7 mmHg to 151 +/- 14/93 +/- 8 mmHg NS). BP recorder every 30 min for 12 hours revealed a decrease under N (160 +/- 18/105 +/- 10 mmHg to 142 +/- 16/94 +/- 10 mmHg; p less than 0.001/p less than 0.001) with a placebo effect in the control group on the diastolic BP (160 +/- 15/103 +/- 7 mmHg to 156 +/- 16/100 +/- 8 mmHg/NS/p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Explant culture of human fetal small intestine.

Human fetal intestine (10-14 wk gestation) has been cultured as explants in a serum-free Leibovitz L-15 medium for periods up to 9 days. As determined by light microscopy, the overall architecture of the intestinal explant was maintained throughout the culture period. At the ultrastructural level the villus absorptive cells remained tall with well-defined brush border, apical tubular system, and supranuclear and infranuclear accumulations of glycogen. All other epithelial cell types were also preserved. The incorporation of [3H]thymidine and [3H]leucine continued during the culture period, reflecting a sustained synthesis of deoxyribonucleic acid and proteins. The hydrolytic activities of the brush border membrane were established based on data obtained throughout the course of the culture of a large number of intestinal specimens. Sucrase, maltase, glucoamylase, trehalase, lactase, alkaline phosphatase, and gamma-glutamyl transpeptidase activities increased during the 9 days of culture even though different patterns were recorded. These observations clearly established that human fetal small intestine can be maintained in organ culture for at least 9 days in a serum-free medium.

Culture Media↗
PubMed1985

Influence of epidermal growth factor on the maturation of the fetal mouse duodenum in organ culture.

The purpose of this work was to study the direct influence of epidermal growth factor (EGF) on the maturation of the fetal mouse duodenum in organ culture. Duodenal explants, resected at 17 days of gestation, were cultured during 48 h at 37 degrees C in Leibovitz L-15 serum-free medium alone or supplemented with EGF (100 ng/ml). Differentiation of absorptive cells was evaluated by measuring brush border hydrolytic activities. After 48 h of culture with and without EGF, villous architecture and the fine structural characteristics of the tissues are preserved. In control explants, the level of alkaline phosphatase, maltase, trehalase, and sucrase activities as well as the protein and DNA contents remain comparable to the values measured in 17-day explants at the beginning of the culture period, while lactase activity falls drastically. In explants cultured with EGF, the level of alkaline phosphatase, maltase, and trehalase activities and the protein contents significantly increase while sucrase activity and DNA contents are unchanged, and lactase activity remains under the onset level. From these results, it was concluded that EGF influences directly the maturation of some brush border enzymes in the duodenum during the fetal period.

Animals↗
PubMed1985

Influence of hydrocortisone on human fetal small intestine in organ culture.

The influence of hydrocortisone on the differentiation and proliferation of human fetal small intestine was studied. Fetal intestine (12- to 14-week gestation) was cultured during 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with hydrocortisone (12.5, 25, and 50 ng/ml). The addition of different concentrations of hormone did not affect the morphology of the intestinal explants. Brush border membrane hydrolytic activities, namely, sucrase, lactase, glucoamylase, trehalase, and alkaline phosphatase activities, were assayed in the intestinal tissue. A specific increase of lactase and alkaline phosphatase activities was induced by the addition of 25 and 50 ng hydrocortisone/ml culture medium. The DNA synthesis evaluated by the incorporation of [3H]thymidine was increased by the addition of 50 ng hydrocortisone/ml. The sites of incorporation into the different layers of the intestinal wall were studied by radioautography. The incorporation of the radioactive precursor occurred mainly in the epithelium and to a lesser degree in the mesenchyme and muscular layers. Labeled epithelial nuclei were located in the intervillous areas and developing crypts but not on the villi. The addition of hydrocortisone induced a significant increase of the labeling index of the epithelial cells. The present work provided for the first time some basic data on the influence of hydrocortisone on brush border hydrolytic activities and on epithelial cell proliferation of human fetal small intestine.

Cell Differentiation↗
PubMed1985

Development of enteropeptidase activity in mouse small intestine: influence of hormones.

The postnatal development of enteropeptidase activity has been examined on mucosal scrapping of the proximal part of the mouse small intestine. The activity was present at birth and remained low during the first 15 days of life. Then it rapidly increased reaching adult level within 2 days. Daily administration of cortisone acetate (25 micrograms X g body weight (bw)-1 X day-1), insulin (12.5 mU X g bw-1 X day-1), or epidermal growth factor (4 micrograms X g bw-1 X day-1) during 3 days to 8-day-old mice induced a premature increase of enteropeptidase. The maximal increase was observed with cortisone treatment, the enzymic activity representing 70% of the adult level. Thyroxine alone (1 microgram X g bw-1 X day-1) had no significant effect on enteropeptidase activity. Hormonal interactions have been evaluated by studying the effects of different hormonal combinations. Finally, cortisone acetate which has a major effect on this activity during suckling period was unable to influence adult small intestinal enteropeptidase activity.

Animals↗
PubMed1984

Comparative study of some intestinal brush border membrane enzymes during perinatal development of the mouse.

Intestinal brush border membrane (bbm) fractions have been isolated from fetal and neonatal mice. The existence of discordant developmental patterns of intestinal enzymatic activity derived from total homogenate and bbm fraction was confirmed. It originates chiefly from two phenomena: (a) variations in the state of purity of brush border fractions, and (b) loss of brush border membrane enzyme activities in supernatant that increases with age. The phenomenon of solubility for glucoamylase and alkaline phosphatase is already present two days before birth.

Aging↗
PubMed1984

Comparative study of the effect of hydrocortisone and thyroxine on suckling mouse small intestine in organ culture.

The influence of hydrocortisone (10(-8)--10(-5) M) and thyroxine (10 (-9)--10(-6) M) on intestinal epithelial cell differentiation and proliferation have been studied using explants of suckling mouse jejunum maintained in serum-free organ culture. Hydrocortisone induced the appearance of sucrase activity and increased trehalase, glucoamylase, lactase and alkaline phosphatase activities. Thyroxine was completely ineffective at all the concentrations used. None of these hormones affected the mitotic activity or the 3H-thymidine incorporation into DNA. These results demonstrate that hydrocortisone but not thyroxine acts directly on intestinal brush border membrane differentiation and that both hormones do not influence the proliferation of the epithelial cells during postnatal development.

Animal Population Groups↗
PubMed1984

Insulin influences the maturation and proliferation of suckling mouse intestinal mucosa in serum-free organ culture.

Explants of suckling mouse jejunum have been maintained in serum-free organ culture with or without insulin added to the medium in order to determine the possible direct effect of this hormone on the hydrolytic functions of the brush border and on the proliferation of the crypt cells. The addition of insulin induced the precocious appearance of sucrase activity and increased trehalase, glucoamylase and lactase activities. Alkaline phosphatase activity remained unaffected in the tissue as well as in the medium. An increased DNA content and 3H-thymidine incorporation into DNA were already recorded after 24 h of culture. The mitotic index was significantly increased after 24 h and remained elevated when the culture was extended to 48 h. These results show that insulin directly influences the enzymatic maturation and the proliferation of intestinal epithelial cells of suckling mouse.

Animals↗
PubMed1983

Extracts of rat amniotic fluid contain a potent inducer of intestinal crypt formation.

The effect of acid, basic, and organic extracts from Long Evans rat amniotic fluid (RAF) and from Swiss ICR mouse amniotic fluid (MAF) was studied on 15-day fetal mouse duodenal mucosa in organ culture. Amniotic fluids (20 ml) were lyophilized and extracted 1) with CHCl3:MeOH and the organic phase was evaporated; then 2), the residue was acidified with a solution of 0.1 N HCl in 10% acetic acid and the liquid phase was lyophilized; finally 3), 0.01 M NH4OH was added to the residue and the liquid phase was lyophilized. The product of each extraction was added to 20 ml of Trowell T8 medium. Acid and basic extracts of RAF and MAF have no effect on the formation of duodenal villi and crypts after 48 hours of culture. With the organic extract of MAF, small villi are present after 48 hours of culture and absorptive cells are poorly differentiated. With the organic extract of RAF, well-developed villi have differentiated after 48 hours of culture; moreover, crypts are present at the same stage and Paneth cells are identified within these crypts. During the 8-10 hour period, the explants cultured with the Trowell T8 medium supplemented with RAF or MAF organic extracts show a 35% increase in 3H-thymidine incorporation over the controls cultured with Trowell T8 medium alone. These results indicate that organic extracts from MAF and RAF are able to promote villus formation in undifferentiated explants from 15-day fetal mouse duodenum in organ culture. Furthermore, RAF organic extract contains a factor that can induce the formation of duodenal crypts and the differentiation of Paneth cells in culture at least 2 days before their normal appearance.

Amniotic Fluid↗
PubMed1983

Organ culture of the small intestine of the suckling mouse in a serum-free medium.

Proximal and distal parts of the small intestine of 8-day-old suckling mice can best be maintained for 48 h in a serum-free organ culture system, Leibovitz L-15, at room air and room temperature. As determined by light and electron microscopy, the villous architecture was preserved as well as the classical ultrastructure of the enterocytes. Incorporation of 3H-thymidine and 3H-leucine continued during the culture period, reflecting a sustained synthesis of DNA and proteins for at least 48 h. The hydrolytic activities of the brushborder membrane, namely of lactase (L), trehalase (T), glucoamylase (GA) and alkaline phosphatase (AlPase) were measured in the explants as well as the culture medium. The overall enzymatic activities were increased as compared to the controls. In the tissue, L, GA and T activities remained stable or even increased during culture while in the medium an accumulation of enzymatic activities was noted especially for GA an AlPase. These results show that the morphological as well as the functional integrity of the mucosa is preserved for at least 48 h when small intestine of suckling mice is cultured in a serum-free medium.

Animal Population Groups↗
PubMed1983

Synergistic effects of insulin and thyroxine on the differentiation and proliferation of epithelial cells of suckling mouse small intestine.

The interactions between insulin, cortisone and thyroxine on the functional maturation of the small intestine were investigated. 8-day-old suckling mice received one injection/day during 3 days of a single hormone or of the following hormonal combinations: insulin plus cortisone or insulin plus thyroxine. The differentiation of intestinal epithelial cells was evaluated by measuring brush border membrane hydrolytic activities and proliferation by establishing the mitotic index and 3H-thymidine incorporation into DNA. The effects of cortisone and insulin on enterocyte's differentiation are additive. Thyroxine accelerates the differentiation and has a limited action on cell proliferation. Insulin exerts a sustained effect on these two aspects of the intestinal maturation and, furthermore, acts in synergism with thyroxine. It appears that insulin, cortisone and thyroxine have their own specific effect on differentiation and proliferation of the epithelial cells and that these three hormones act in cooperation to induce the maturation of the suckling mouse small intestine during postnatal development.

Animals↗
PubMed1982

Development of peroxisomes in amphibians. II. Cytochemical and biochemical studies on the liver, kidney, and pancreas.

The ontogeny of catalase-containing organelles was studied by cytochemical and biochemical methods in the liver, kidney, and pancreas during the development of Rana catesbeiana. The biochemical differentiation of peroxisome in the liver and kidney was compared to that of Xenopus laevis. Catalase activity was localized after incubation in DAB medium and studied biochemically by a spectrophotometric method. In Rana Catesbeiana the number of catalase-positive organelles per cell section is low in all three organs during premetamorphosis; their number increases substantially in the liver and kidney of froglets, while it remains almost stable in the pancreas. No further increase is observed in the adult. Biochemically, the liver, kidney, and pancreas of tadpoles exhibit, respectively, 12,22 and 63% of the catalase activity found in the adult tissues. After metamorphosis an important increase of catalase activity is particularly noted in liver and kidney, the activity being, respectively, 43 and 77% of that of adult bullfrogs. On the other hand, no change in catalase activity in the liver and kidney is noted during the entire development of Xenopus laevis. The present study illustrates the very different developmental pattern of catalase activity observed during the development of two anuran amphibians. The different development pattern of the same enzyme within the small intestine, liver, kidney, and pancreas in Rana catesbeiana is also stressed.

Aging↗
PubMed1981

Establishment of regional differences in brush border enzymatic activities during the development of fetal mouse small intestine.

In order to study the establishment of regional differences in brush border enzymic activities during the development of fetal mouse small intestine we have followed (1) the differentiation of microvilli by morphometry, and (2) the developmental pattern of three brush border enzymes (lactase, glucoamylase and alkaline phosphatase). From day 16 to day 19 of gestation, the height of duodenal microvilli increases 2.4 times on the absorptive cells located near the tip of the villi. During the same period in the upper half of the duodenal villi, the number of microvilli per square micrometer rises by a factor of 2.4 and the microvillous surface area increases by a factor of 5.2. The differentiation of ileal microvilli follows a similar pattern but they are always shorter and less numerous than those of the duodenum. Lactase activity appears at 18 days of gestation; the other two brush border enzymes are first detected at 16 days of gestation. Afterwards all three enzyme activities increase rapidly and a decreasing gradient of activity is established from the proximal to the distal segment of the small intestine. Hence, the structural development of the microvilli and the appearance of brush border enzyme activities occur simultaneously and a proximo-distal gradient is already established at 16 days of gestation.

Alkaline Phosphatase↗