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Biomedical subjects

G Durand

Publications and source records attributed to G Durand.

At least 289 records · Page 16Linked to original sources
PubMed1980

[Polyunsaturated fatty acids and aging. Lipofuscins : structure, origin and development].

In the last century, dense, pigmented bodies were observed on nerve cell sections, and the quantity of those pigments in the neurons was correlated to the age of the individual. Light microscopy has shown the presence of the pigments in the cells of most tissues and organs in both vertebrates and invertebrates, and they have also been seen in cultured cells. However, these commonly found cellular components have only have studied in detail since the last 25 years, using electron microscopic, histochemical and biochemical techniques to try to describe their nature, origin, development and possible physiological role. The comparable morphology, composition and physicochemical properties of these various pigments indicate that they are all produced by the same biochemical mechanism, including: 1) the peroxidation of the polyunsaturated fatty acids of cellular membranes by free radicals; 2) the reaction of lipid peroxidation end-products(s) with proteins, giving fluorescent polymerized compounds; 3) the combination of those polymerized elements and the peroxidized lipids. Different names have been used for these pigments, the most common of which in English are: "age pigment", "ceroid" and "lipofuscins". However, due to their common origin and their fluorescence, they are tended to be grouped under the term lipofuscins (in French: lipofuscines). Recent studies have confirmed that cellular lipofuscin concentration is definitely related to the physiological age of the individual. This concentration varies depending on the tissue and the organ; it is controlled by intrinsic regulatory factors, but also by environmental conditions, such as nutrition, physical activity, stress and hygienic conditions.

Aging↗
PubMed1980

Preliminary observations of the significance of monitoring tricyclic antidepressant plasma levels in the pediatric patient.

Plasma concentrations of clomipramine and desmethylclomipramine were monitored together with clinical effects over a period of 1--9 months in children and young adolescents (5--19 years of age) receiving clomipramine because of depressive features or enuresis. Data indicate that in the child, clomipramine is rapidly absorbed while its disposition rate is age dependent, as indicated by the significantly lower level:dose ratio (p less than 0.01) observed in the younger groups (5--10; 10--15 years). The incidence of side effects was clearly related to clomipramine plasma concentrations, whereas no relationship could be observed for the desmethyl metabolite. In the case of enuresis, a therapeutic effect was observed at clomipramine concentrations of 20--60 ng/ml, while lower or higher levels were associated with lack of therapeutic effect or adverse effects. No relationship was found between oral daily doses and clomipramine or desmethylclomipramine plasma concentrations. The data point to the usefulness of monitoring drug plasma levels in children undergoing treatment with tricyclic antidepressive drugs.

Adolescent↗
PubMed1980

[A case of disseminated histoplasmosis due to Histoplasma capsulatum (author's transl)].

A case is reported of American histoplasmosis due to Histoplasma capsulatum presenting as a hepatic granulomatosis. The patient was a young adult from Haiti and investigations revealed the presence of an ulcerous enterocolitic suggesting tuberculosis or Crohn's disease. The condition became worse after antituberculous therapy and corticoids, and operation was necessary. Extemporaneous histological examination, of the colonic ulcerations showed Histoplasma capsultaum yeasts. The patient, who had a cellular immunity deficiency, died during antifungal treatment with amphotericin B of the disseminated histoplasmosis is rare: 1 case in 5000 American histoplasmosis cases. Digestive tract lesions, usually detected during operation or autopsy, are found in about 20% of cases. In the present observations the diagnosis of American histoplasmosis was based on the country of origin of the patient, but this was not confirmed: the immunological reactions were and remained negative and no yeasts were demonstrated after staining of pre-operative biopsy specimens (colon and liver particularly). Also, serial sections conducted after the diagnosis had been established demonstrated the presence of Histoplasma capsulatum in the colon sample removed during colonoscopy.

Adult↗
PubMed1979

Haloperidol plasma level monitoring in pediatric patients.

Plasma levels of haloperidol were monitored in children and teenagers suffering from psychotic episodes and/or abnormal movements (tics and Gilles de la Tourette's syndrome). Steady-state concentrations of haloperidol ranged from 0.7 to 19 ng/ml without any apparent relationship with the administered dose (15--285 micrograms/kg/day) and a 15-fold variability was observed for the same daily dosage. On the contrary, a significant (p < 0.02) relationship was found between the age of the patients and the plasma concentrations to dose ratios, lower values being present in younger patients. Side effects too appeared to be related to plasma levels, with a significant increase (p < 0.01) in incidence for concentrations over 6 ng/ml. In most of the cases suffering from tics and Gilles de la Tourette's syndrome, a positive response was associated with plasma levels of 1--4 ng/ml, while no relationship could be established for the psychotic group. The relevance of monitoring plasma drug levels when prescribing haloperidol in pediatrics is discussed.

Adolescent↗
PubMed1979

[Mechanism of lymphocyte activation by periodic acids. Blastogenesis and induction of immunomodulator populations].

Mild periodate treatment is mitogenic for T lymphocytes. With murine spleen cells periodate oxidation is effective between C8 and C9 on sialyl acid residues. With human blood lymphocytes this oxidation occurs between C7 and C8 of these residues. In vitro immune response is inhibited by periodate treatment. Activation of an immunosuppressive T lymphocyte population is obtained. Similar results are performed with human blood lymphocytes.

Animals↗
PubMed1979

[Experimental alpha-chymotrypsin model of glaucoma in the rabbit: histopathological studies (author's transl)].

The injection of alpha-chymotrypsin into the posterior chamber of the eye is known to produce an experimental ocular hypertension of long duration in animals. The present study reports the pathological changes which occur in the eye during the first nine months after the ocular injection of alpha-chymotrypsin in rabbits. Six weeks after treatment most of the eyes showed a buphthalmia and an intraocular pressure elevation which varied greatly from animal to animal. The anterior chamber angle of the treated eyes showed a progressive enlargement. Several days after the enzyme injection a transient increase in thickness of the cornea and Descemet membrane was noted. Cupping of the optic disc, characterized by a total disappearance of the optic nerve head fibers and an excavation beginning at margins of the retina appeared after four months and in most cases were present seven months after the treatment. More or less prominent retinal degeneration was also evidenced three months after enzyme injection. The results indicate alpha-chymotrypsin-induced occular hypertension in the rabbit leads after several months to pathological change in the eye analogous to that observed in human glaucoma.

Animals↗
PubMed1979

[Treatment of hypercholesterolemia in the male rat by introduction of soya oil supplemented or not with sardine oil in the diet].

Substituting soya oil for lard considerably reduced hypercholesterolemia in the male rat with induced hypercholesterolemia due to a dietary overlead of cholesterol and sodium deoxycholate. The decrement was more marked when a mixture of 80 p. 100 soya oil + 20 p. 100 sardine oil replaced the lard. This improvement of the hypocholesterolemic effect by adding sardine oil to soya oil was due to the long-chain fatty acids (mainly C20:5 and/or C22:5 n-3 in the fish oil).

Animals↗
PubMed1978

[Metabolic activity of adipose tissue in the goat during gestation and at the beginning of lactation].

In 5 French Alpine goats, omental adipose tissue acetyl-CoA carboxylase, glucose-6-phosphate deshydrogenase, malic enzyme and lipoprotein lipase activities significantly decreased during the third month of gestation, whereas plasma non-esterified fatty acid and triacyglycerol contents increased. This probably reflects an early decreasing rate of adipose tissue anabolism during gestation in the Goat. At the third week of lactation, anabolic activities relative to DNA content of adipose tissue were extremely low, and the tissue weight relative to DNA was lower than during gestation. Metabolic alterations of omental adipose tissue in early lactation do not seem to be related to milk production level. These results could contribute to a better control of the kinetic of body lipid stores during the reproductive cycle in high milk yielding ruminants.

Acetyl-CoA Carboxylase↗
PubMed1978

[Changes in mammary tissue lipid metabolism in the goats during the first 2 months of lactation].

5 French Alpine Goats were studied after normal or premature parturition. Mammary tissue acetyl-C oA carboxylase, glucose-6-phosphate dehydrogenase, malic enzyme and lipoprotein lipase (LPL) activities varied in parallel with milk fat secretion from the 3rd to the 9th week of lactation. Variations of mammary LPL activity and of long chain fatty acid secretion were positively highly correlated during that period. In goats with normal parturition, lipogenic activities seemed to reach a maximum level shortly after parturition. There was a positive correlation between mammary Ll activities and plasma non esterified fatty acid contents, possibly reflecting a relationship between adipose tissue mobilisation and mammary metabolism.

Acetyl-CoA Carboxylase↗
PubMed1978

Production of L-lysine by immobilized trypsin. Study of DL-lysine methyl ester resolution.

The possibility of producing L-lysine from chemically synthesized DL-lysine has been investigated. Optical resolution of racemic DK-lysine may be achieved by using the stereospecific esterasic activity of trypsin on DL-lysine methyl ester, which gives L-lysine and unchanged D-lysine methyl ester. SL-lysine methyl ester spontaneous hydrolysis may be neglected when operating at pH 5.5 and 30 degrees C. Effect of pH and substrate concentration on hydrolysis rate has been investigated when using as a catalyst either soluble or immobilized trypsin. For this purpose, trypsin was coupled onto an amine porous silica, Spherosil, activated with glutaraldehyde. The optimal pH is 5.8 for soluble trypsin and 6.0 for immobilized trypsin. It was yet possible to lower the parent optimal pH of immobilized trypsin, and thus increase its activity at 5.5, by co-grafting onto Spherosil an aminosilane, for enzyme coupling via glutaraldehyde activation and a positively charged diethyl amino ethyl (DEAE) silane, for decreasing the pH of trypsin microenvironment.

Animals↗
PubMed1978

Colorimetric assay of sialic acid by a methyl-3-benzothiazolinone-2-hydrazone reactant.

A colorimetric assay of sialic acid has been developed in which bound sialic acid is oxidized by periodic acid so as to quantitatively release formaldehyde. In the second step of the reaction formaldehyde reacts with methyl-3-benzothiazolinone-2-hydrazone, giving a colored compound. This method does not require a prior hydrolysis and presents the advantage of great accuracy.

Benzothiazoles↗
PubMed1978

Development of digestive enzymes in the piglet from birth to 8 weeks. I. Pancreas and pancreatic enzymes.

The development of pancreatic tissue (fresh weight, total proteins, RNA and DNA) and of the level of pancreatic enzymes (trypsin, chymotrypsin, lipase and amylase) of the piglet has been followed from birth to the age of 8 weeks in 10 animals at each of 7 stages. There was an increase with age and body weight of the total fresh weight of the exocrine pancreas. From birth until 4 weeks the development of the pancreatic gland was due to hyperplasia; from the 4th week till the 8th week of age, it was due both to hyperplasia and hypertrophy. There was a specific period, at the age of 3--4 weeks, from which total enzymatic activities markedly increased. Furthermore, from the 4th week of age there was a rise in the intake of total dietary proteins, fat and carbohydrates, due to the intake of solid food.

Age Factors↗