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Biomedical subjects

D Menard

Publications and source records attributed to D Menard.

32 records · Page 2Linked to original sources
PubMed1991

Occurrence of faecal bacteria, Salmonella and antigens associated with hepatitis A virus in shellfish.

An investigation was carried out over a one year period to examine jointly the occurrence of faecal bacteria, salmonella and the presence of antigens associated with the hepatitis A virus (HAV) in oysters (Crassostrea gigas), mussels (Mytilus edulis, Mytilus galloprovincialis) and cockles (Cerastoderma edule), taken from 8 shellfish farming areas or natural beds along the French coast. For the faecal coliforms (FC) and faecal streptococci (FS), statistical analysis of the 176 samples examined shows a statistically significant difference between sampling stations (F = 44.39 and F = 26.69 respectively, p less than 0.001): 4 of the 8 stations are more highly contaminated. Salmonella and antigens associated with HAV were detected in 5% and 1.7% respectively of the samples analysed. Frequency of isolation of salmonella is higher for the group of sampling stations where the mean levels of contamination by FC and FS are highest. The presence of HAV associated antigens was detected for the group of stations showing the lowest mean contamination levels. Taking all sample stations together, the percentage of isolation of salmonella differs significantly (chi 2 = 7.28, p less than 0.01) for the two classes of FC established on the basis of the threshold value (300 FC). There is no difference between the two classes of FS. For the HAV-associated antigens, detection percentages are similar for the two classes of results for FC and FS. Within each sampling station, considered independently, no particular correlation was found between the various viral and bacterial markers investigated.

Animals↗
PubMed1990

Effects of captopril and minoxidil on left ventricular hypertrophy in resistant hypertensive patients: a 6 month double-blind comparison.

In a double-blind 6 month trial, the cardiac effects of captopril and minoxidil, administered as third step treatments, were compared in 34 men with essential hypertension and diastolic blood pressure greater than 95 mm Hg who were taking 200 mg/day of metoprolol and 80 mg/day of furosemide. Average daily doses of captopril and minoxidil were 269 mg (range 150 to 300) and 20 mg (range 7.5 to 30), respectively. At the end of the 6 months' treatment, blood pressure had dropped significantly in both groups, but echocardiographic criteria of hypertrophy improved only in the captopril group (intragroup comparison): blood pressure, thickness of the intraventricular septum and posterior wall, and the left ventricular mass index, respectively, decreased from 163/102 to 135/89 mm Hg (p less than 0.001), 17.4 to 15.9 mm (p less than 0.05), 14.5 to 13.4 mm (p less than 0.05) and 236 to 198 g/m2 (p less than 0.001). In the minoxidil group, blood pressure dropped from 160/99 to 137/87 mm Hg (p less than 0.001), but echocardiographic criteria were not significantly modified. Fractional shortening remained normal in both groups. These results show that in patients with severe left ventricular hypertrophy, captopril-based triple therapy reduces left ventricular mass without altering systolic performance, whereas minoxidil-based therapy does not.

Adult↗
PubMed1988

Autoradiographic localization of [3H]-thymidine incorporation in developing human esophagus.

Cell proliferation in the developing human esophagus was investigated by autoradiography using organ culture. The sites of [3H]-thymidine uptake were localized in the epithelium, the mesenchyme, and the muscularis externa of fetal esophageal explants from 10 to 16 weeks of gestation. Proliferating cells were abundant throughout the stratified epithelium at 10 weeks of gestation. Many labeled nuclei in the mesenchyme and the muscular layer were observed. With the development of the stratified columnar ciliated epithelium, a confinement of the proliferating zone in the basal cell layers occurred, and ciliated cells never appeared labeled. The quantitation of proliferating cells showed a labeling index at its highest value between 10 and 12 weeks; this drastically decreased between 12 and 14 weeks' gestation. A similar pattern was noted for the mesenchyme, while the labeling index in the muscularis externa peaked during the 11-14 weeks period. In all fetuses, the highest labeling index was always recorded in the epithelium. The biochemical quantitation of the [3H]-thymidine uptake into the total esophageal DNA clearly supported the continuous decrease of the cell proliferation determined by autoradiography between 10 and 16 weeks of gestation. The present investigation provides for the first time basic quantitative data regarding cell proliferation during a particular developmental phase of the human esophagus.

Cell Division↗
PubMed1983

Development of peroxisomes in amphibians. III. Study on liver, kidney, and intestine during thyroxine-induced metamorphosis.

This investigation was undertaken to study the ontogeny of hepatic, renal, and intestinal peroxisomes and/or microperoxisomes during thyroxine-induced anuran metamorphosis. Catalase activity was localized cytochemically after incubation in DAB medium, and studied biochemically by a spectrophotometric method. Our morphological and biochemical investigations suggest the formation of a new population of peroxisomes during the hormonal treatment. This is obvious especially for microperoxisomes of the intestinal epithelium since the larval tissue is completely replaced by a new layer during thyroxine-induced metamorphosis. For the peroxisomes of hepatocytes and kidney proximal tubule cells, our assumption is based on the following observations: 1) The number of peroxisomes increases in liver and kidney during thyroxine treatment; 2) this proliferation is accompanied by an enlargement of renal peroxisomes; and 3) 16 days after the beginning of the hormonal treatment, 5.4- and 2.4-fold increases are found for the specific activities of hepatic and renal catalase, respectively. A temporal coordination exists between the structure and the metabolism of peroxisomes and mitochondria during thyroxine-induced metamorphosis.

Animals↗
PubMed1979

Organ culture of adult mouse intestine. III. Behavior of the proteins, DNA content and brush border membrane enzymatic activities.

The proteins, the DNA content and the brush border membrane enzyme activities of adult mouse intestinal explants have been measured during a 24-hr organ culture. These activities were not modified in comparison with the controls at the beginning of the culture. The activity of the enzymes secreted in the medium during the 24-hr culture was equal to the activity present in the explants at the start of the culture. These results show that several metabolic functions of the intestine are fully preserved in organ culture.

Alkaline Phosphatase↗
PubMed1979

Amphibian intestinal brush border membranes-I. Isolation from Rana catesbeiana tadpole.

1. Intestinal brush border membrane vesicles have been isolated form Rana catesbeiana tadpole. 2. Electron microscopy of brush border membrane vesicles demonstrates a fairly homogenous preparation of vesicles, some of them still containing electron dense material. 3. The dense vesicles probably comprise both microvillus core and membrane. 4. Negative staining of vesicles reveals the presence of knob-like structures (particles) covering the outer surface of the membrane. 5. The membranous fraction is characterized by a high specific activity of alkaline phosphatase, trehalase, glucoamylase, maltase and gamma-glutamyltranspeptidase.

Animals↗
PubMed1978

Organ culture of adult mouse intestine IV. Stimulation of glucose-6-phosphatase in vitro.

Explants of adult mouse jejunum have been maintained in organ culture with or without fructose added to the medium in order to stimulate the intestinal glucose-6-phosphatase (G-6-Pase). When the fructose is added, at the beginning of the culture, a three-fold increase of G-6-Pase in measured during the first 24 h. If the fructose is added after 24 h of culture, no significant increase of the G-6-Pase is registered in comparison with the controls. Proteins, DNA content and dissacharidase activities are not modified during the culture. Alkaline phosphatase activity presents a twofold increase in the controls and stimulated explants. The ultrastructural localization of the G-6-Pase is not altered during the culture.

Alkaline Phosphatase↗
PubMed1978

IgG versus albumin for measurement of plasma volume in normal and hypertensive men.

Labeled IgG was evaluated versus labeled albumin for measurement of plasma volume, to see whether it would give a smaller initial dilution volume (indicating a smaller premixing extravascular loss of label) and a smaller difference between initial dilution volume and dilution volume at time 10 min (indicating a negligible extravascular loss in the first 10 min after mixing). IgG was found to have a lower transcapillary escape rate than albumin (P less than 0.01) in eight normal volunteers and in eight hypertensive subjects, hypertension being associated with an increased transcapillary escape of both proteins. Despite this, the dilution volumes obtained were indistinguishable and the need for a correction through a retropolation procedure was the same with both proteins. Albumin and IgG dilution volumes were highly correlated in 21 subjects (r=0.977) so that use of labeled IgG is a proper alternative to use of labeled albumin for plasma volume determination. However, since IgG brings no consistent advantage, labeled albumin remains the best available tracer for that purpose.

Blood Pressure↗
PubMedDate not supplied

The aging athlete.

In summary, the purpose of this material is to demonstrate that the aging athlete does differ from the younger competitor in many facets. There are physiological, structural, and psychosocial differences which distinguish them as a unique entity in the athletic world. Despite the unavoidable alterations that the passage of time imposes on our bodies, these competitors are still capable of incredible performances of strength, skill, and endurance. In reference to injury, these athletes are at risk from both their current program and their past indiscretions. The literature strongly suggests that the greatest threat to the health of the aging athlete is not the aging process itself but rather inactivity. Astrand concurs with this and states that "there is less risk in activity than in continuous inactivity--it is more advisable to pass a careful physical examination if one intends to be sedentary in order to establish whether one's state of health is good enough to stand the inactivity." It appears that the body systems were designed to reinforce activity and when there is disuse, a large number of atrophic changes take place. It has been estimated that regular exercise may be able to retard the physiologic decline associated with old age as much as 50%. Taken in this light, exercise is truly a fountain of youth from which we can all rejuvenate ourselves. Science has proven that life does not begin at 40, but it has also demonstrated that it does not have to end there. As one author so aptly states, "Not too many years ago the words grandma and grandpa conjured images of rocking chairs and inactivity."(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗