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Biomedical subjects

G Durand

Publications and source records attributed to G Durand.

At least 217 records · Page 12Linked to original sources
PubMed1989

The effects of dietary alpha-linolenic acid on the composition of nerve membranes, enzymatic activity, amplitude of electrophysiological parameters, resistance to poisons and performance of learning tasks in rats.

Feeding rats diets containing oils that have a low alpha-linolenic acid [18:3(n-3)] content, such as sunflower oil, results in reduced amounts of docosahexaenoic acid [22:6(n-3)] in all brain cells and organelles compared to rats fed a diet containing soybean oil or rapeseed oil. During the period of cerebral development there is a linear relationship between the n-3 fatty acid content of the brain and that of food until alpha-linolenic acid represents approximately 200 mg/100 g food [0.4% of the total dietary energy for 18:3(n-3)]. Beyond that point brain levels reach a plateau. Similar values are also found for other organs. The level of 22:6(n-3) in membranes is little affected by the dietary quantity of linoleic acid [18:2(n-6)] if 18:3(n-3) represents approximately 0.4% of energy. In membranes from rats fed diets containing sunflower oil, Na+, K(+)-ATPase activity in nerve terminals was 60%, 5'-nucleotidase in whole brain homogenate was 80%, and 2',3'-cyclic nucleotide 3'-phosphodiesterase was 88% of that in membranes from rats fed diets containing soybean oil. A diet low in alpha-linolenic acid leads to anomalies in the electroretinogram, which partially disappear with age. It has little effect on motor activity, but it seriously affects learning tasks as measured with the shuttle box test. Rats fed a diet low in alpha-linolenic acid showed an earlier mortality in response to an intraperitoneal injection of a neurotoxin, triethyltin, than did rats fed a normal soybean oil diet.

Animal Feed↗
PubMed1989

Increased affinity to concanavalin A and enhanced secretion of alpha 1-acid glycoprotein by hepatocytes isolated from turpentine-treated rats.

Hepatocytes were isolated from adult rats at various times after subcutaneous injection of turpentine (1 ml). The affinity to concanavalin A (Con A) of alpha 1-acid glycoprotein (AGP) and the intracellular content and rate of secretion of AGP and albumin were evaluated over a period of 19 days. Inflamed hepatocytes secreted mainly the Con A-reactive form of AGP whereas control hepatocytes secreted a higher amount of the Con A-non-reactive form. The intracellular content and rate of secretion of AGP by inflamed hepatocytes increased markedly whereas those of albumin decreased. However, when the residence time (ratio of intracellular content to rate of secretion) was evaluated, it appeared that the efficiency of secretion of both proteins was higher than in control hepatocytes. The changes in the affinity of AGP to Con A and in the secretion of AGP and albumin were reversible. These findings indicate that acute inflammation leads to posttranslational alterations during the intracellular transit of these secretory proteins.

Albumins↗
PubMed1989

[Acceptability of the Hemoccult test in general medical practice. Results of a pilot study].

In view of preparing a controlled trial to assess the efficacy of screening for colorectal cancer by fecal occult blood testing in reducing cancer mortality, a pilot study was performed to evaluate the acceptability rate of the Hemoccult test in non selected subjects consulting in a general practice. 566 subjects aged 45 to 74 years from two small towns, Neuville-aux-Bois (Loiret) and Vicherey (Vosges) were included in the study. The screening test was proposed by GPs to 89.2% of their patients; of these, 5.6% refused the test and 9.4% did not return it. Of the tests carried out, 80.8% were performed spontaneously, and 19.2% after a recall letter. Acceptability depended neither on age or on sex. The patients' confidence in his GP was the most important acceptability factor (60%), followed by explanations the GP had provided, and ease of application. The results suggest that after receiving the correct information, a GP will succeed in prescribing the Hemoccult test to most high-risk subjects and that acceptability then proves excellent. Experience drawn from the pilot study has been very useful in conceiving the on-going controlled trial in Burgundy.

Aged↗
PubMed1989

[Cervical smears in general medicine. Evaluation of the regular performance of cervical smears among the patients of general practitioners in the Rhône-Alpes region].

Cervical smears in the area of "Rhône Alpes" are evaluated through a population examined by general practitioners. Among 10,000 examined women, aged from 15 to 69 years, 20% had never been smeared. In 8% of the remaining 8,000 cases, the smear was realized since more than 5 years. Absence or prolonged delay was more frequently met with more aged women, from unfavorable or rural area; or foreigner (from South of Europe or from North-West Africa). These results are discussed and compared with those of other studies whether inside or outside France. Certainly, they are under-estimated as regards the general population. In fact, this study considers an already mostly medicalized population together with volunteer general practitioners. However, it's always less medicalized than in most of French studies considering this subject.

Adolescent↗
PubMed1988

400-MHz 1H-NMR spectroscopy of fucosylated tetrasialyl oligosaccharides isolated from normal and cirrhotic alpha 1-acid glycoprotein.

The comparative study of fucosylated tetrasialyl-oligosaccharides isolated from normal and cirrhotic alpha 1-AGP was performed using permethylation and 400-MHz 1H-NMR spectroscopy. These results clearly show the tetraantennary structure of these two oligosaccharides with hyperfucosylation for the tetrasialylated fraction from cirrhotic alpha 1-AGP. In the latter oligosaccharide the simultaneous presence on two antennae (7 and 7') of the sialosyl Lewis X determinant NeuAc-(alpha 2-3) Gal(beta 1-4) [Fuc(alpha 1-3)] GlcNAc has been observed. Moreover the 5 and 5' antennae were alpha 2-6 sialylated but without fucose.

Ascitic Fluid↗
PubMed1988

Effects of dietary alpha-linolenic acid deficiency during pregnancy and lactation on lipid fatty acid composition of liver and serum in the rat.

The effects of a dietary alpha-linolenic acid (18:3 n-3) deficiency on lipid fatty acid composition of the liver and serum of lactating rats have been studied during three gestations and over three generations. These females were compared to corresponding females which remained sterile. Two lots of female rats received, respectively, a diet containing lipids either in the form of 1.50 g of sunflower oil per 100 g of diet (deficient diet) or as 1.87 g of soya oil per 100 g of diet (control diet). Both diet contained the same amount of linoleic acid (18:2 n-6), i.e. 940 mg/100 g of diet, but the sunflower diet supplied 43 times less 18:3 n-3 than the soja diet, or 3 mg vs 130 mg/100 g of diet. Results show that successive gestations appeared to be more efficient means of depleting material n-3 PUFA stores than successive generations. The 18:3 n-3 deficient diet caused a considerable decrease in the level of n-3 polyunsaturated fatty acids (n-3 PUFA) in liver and serum lipids, and particularly of 22:6 n-3. This decline was compensated by an increase in the level of n-6 polyunsaturated fatty acids (n-6 PUFA), and particularly by a very high augmentation of 22:5 n-6. The ratio n-6 PUFA/n-3 PUFA in liver phospholipids and in serum lipids was a good index of the adequacy of dietary n-3 PUFA supply. However, the ratio 22:5 n-6/22:6 n-3 was a finer index. This ratio appeared to be a reliable index of dietary n-3 PUFA deficiency when it was higher than 1 in serum lipids of a fasting animal. The proportion of 22:5 n-6 as well as the ratios n-6/n-3 and 22:5 n-6/22:6 n-3, were also increased in the liver phospholipids of lactating females receiving the soya oil diet; this suggested that a supply of 130 mg/100 g of diet, corresponding to a ratio of n-6/n-3 = 7.2, was not sufficient for these rats during pregnancy and lactation. A supply of 200 mg of n-3 PUFA/100 g of diet, corresponding to a ratio of n-6/n-3 = 5, is recommended for these animals.

Animals↗
PubMed1988

Alteration in fatty acid composition of adult rat brain capillaries and choroid plexus induced by a diet deficient in n-3 fatty acids: slow recovery after substitution with a nondeficient diet.

Wistar rats were fed for three generations with a semisynthetic diet containing either 1.5% sunflower oil (940 mg% of C18:2n-6, 6 mg% of C18:3n-3) or 1.9% soya oil (940 mg% of C18:2n-6, 130 mg% of C18:3n-3). At 60 days of age, the male offspring of the third generation were killed. The fatty acyl composition of isolated capillaries and choroid plexus was determined. The major changes noted in the fatty acid profile of isolated capillaries were a reduction (threefold) in the level of docosahexaenoic acid and, consequently, a fourfold increase in docosapentaenoic acid in sunflower oil-fed animals. The total percentage of polyunsaturated fatty acids was close to that in the soya oil-fed rats, but the ratio of n-3/n-6 fatty acids was reduced by threefold. In the choroid plexus, the C22:6n-3 content was also reduced, but by 2.6-fold, whereas the C22:5n-6 content was increased by 2.3-fold and the ratio of n-3/n-6 fatty acids was reduced by 2.4-fold. When the diet of sunflower oil-fed rats was replaced with a diet containing soya oil at 60 days of age, the recovery in content of n-6 and n-3 fatty acids started immediately after diet substitution; it progressed slowly to reach normal values after 2 months for C22:6n-5 and 2.5 months for C22:6n-3. The recovery in altered fatty acids of choroid plexus was also immediate and very fast. Recovery in content of C22:5n-6 and C22:6n-3 was complete by 46 days after diet substitution.

Animals↗
PubMed1988

What does inductance plethysmography really measure?

Inasmuch as it has been claimed that inductance plethysmography can measure cross-sectional area changes, we tested this assumption. We present experimental and computed relationships between self-inductance (L) of coils and areas (A) included inside for a coil with a well-defined side wavy pattern (triangular or sinusoidal) and for a real belt (Respitrace) placed on elliptical or rectangular configurations. The results are applied to the physiological field using measurements obtained from a computed tomography experiment. We demonstrate that the L-A relationships vary not only with shape or ellipticity of the cross section but also with the wavy pattern shape. This last parameter is critical because it is difficult to actually control. When the coil wavy pattern remains steady, there are some physiological situations where inductance plethysmography can more accurately estimate area changes: when the configuration shape is constant, the correspondence between delta L and delta A is almost linear with a shape-dependent sensitivity; when the configuration is nearly circular (ellipticity in the range 0.8-1), the relative error in delta A estimation is less than 5%.

Humans↗
PubMed1987

PAF binding sites. Characterization by [3H]52770 RP, a pyrrolo[1,2-c]thiazole derivative, in rabbit platelets.

52770 RP, the N-(3-chlorophenyl)-3-(3-pyridinyl)-1H,3H-pyrrolo[1,2-c]thiazole -7-carboxamide, displaces in a potent, specific and competitive manner [3H]PAF from its binding sites on rabbit platelets. Since 52770 RP is not structurally related to PAF and has low liposolubility with respect to PAF, it was selected as a potential radioligand for PAF receptor sites. [3H]52770 RP displayed high-affinity, specificity, as well as saturable and displaceable binding to a single class of recognition sites in intact platelets and crude platelet membranes. In these preparations, the values of binding parameters were, respectively, 8.5 and 7.6 nM for Kd, 0.2 pmol/5 X 10(7) platelets and 3.66 pmol/mg protein for Bmax and 0.96 and 0.91 for nH. Inasmuch as the (+)-52770 RP was 300-fold more potent than the (-)-isomer at displacing [3H]52770 RP in intact platelets, the studied binding site manifested stereospecific discrimination. A variety of pharmacological agents including pro- and anti-aggregant compounds did not exhibit affinity for [3H]52770 RP binding sites. In contrast, PAF, some of its active analogues and several recognized PAF antagonists (BN 52021, brotizolam, L-652,731, triazolam), displaced the [3H]52770 RP binding. Studies carried out using [3H]PAF demonstrated that 52770 RP was approximately 4- and 200-fold more potent than L-652,731 and BN 52021 respectively, as a PAF-receptor antagonist. In washed rabbit platelets, the rank order of potency (Ki) for several analogues of 52770 RP, to displace [3H]PAF from its binding sites, was highly correlated (r = 0.96) to their ability to antagonize [3H]52770 RP binding. In functional studies, 52770 RP antagonized not only the PAF-induced aggregation in washed rabbit platelets but also the hypotension evoked by PAF in the anesthetized rat. In this respect, it was 26 and 2 times more potent than L-652,731, respectively. In conclusion, [3H]52770 RP might represent a novel interesting tool for furthering our understanding of the role of PAF binding sites in pathophysiological processes.

Animals↗
PubMed1987

Human alpha 1-acid glycoprotein-exposed macrophages release interleukin 1 inhibitory activity.

The concanavalin A-unreactive variants of alpha 1-acid glycoprotein introduced in culture medium of monocytes/macrophages induces the inhibition of thymocyte proliferative activity of interleukin 1. LPS or LPS receptors were not involved in the activity of alpha 1-acid glycoprotein on macrophages. alpha 1-acid glycoprotein did not show any direct effect on thymocytes whereas the monocyte/macrophage-supernatant inhibited the interleukin 1 proliferative effect. The activity of tumor necrosis factor and interleukin 2 was not altered by the alpha 1-acid glycoprotein-macrophage supernatant.

Animals↗
PubMed1987

Alterations in the carbohydrate moiety of alpha-1-acid glycoprotein purified from human cirrhotic ascitic fluid.

The carbohydrate analysis of alpha 1-AGPc purified from cirrhotic ascitic fluid was performed by immunoaffinity chromatography. It showed a large increase in the fucosyl molar ratio and sugar content (47%). The molar ratio of the oligosaccharides which were released by hydrazinolysis and fractionated by high-performance liquid chromatography confirms the marked increase in fucosyl residues in each fraction. A shift towards fractions with a high degree of branching was also observed. Moreover, the studies of sugar molar ratios and methylation of the tetrasialylated fraction indicated the simultaneous presence of sialyl and fucosyl residues on one of the outer branches.

Ascitic Fluid↗