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Biomedical subjects

G Durand

Publications and source records attributed to G Durand.

At least 145 records · Page 8Linked to original sources
PubMed1993

Brain phospholipids as dietary source of (n-3) polyunsaturated fatty acids for nervous tissue in the rat.

In a previous work, we calculated the dietary alpha-linolenic requirements (from vegetable oil triglycerides) for obtaining and maintaining a physiological level of (n-3) fatty acids in developing animal membranes as determined by the cervonic acid content [22:6(n-3), docosahexaenoic acid]. The aim of the present study was to measure the phospholipid requirement, as these compounds directly provide the very long polyunsaturated fatty acids found in membranes. Two weeks before mating, eight groups of female rats (previously fed peanut oil deficient in alpha-linolenic acid) were fed different semisynthetic diets containing 6% African peanut oil supplemented with different quantities of phospholipids obtained from bovine brain lipid extract, so as to add (n-3) polyunsaturated fatty acids to the diet. An additional group was fed peanut oil with rapeseed oil, and served as control. Pups were fed the same diet as their respective mothers, and were killed at weaning. Forebrain, sciatic nerve, retina, nerve endings, myelin, and liver were analyzed. We conclude that during the combined maternal and perinatal period, the (n-3) fatty acid requirement for adequate deposition of (n-3) polyunsaturated fatty acids in the nervous tissue (and in liver) of pups is lower if animals are fed (n-3) very long chain polyunsaturated fatty acids found in brain phospholipids [this study, approximately 60 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 130 mg/1,000 kcal] rather than alpha-linolenic acid from vegetable oil triglycerides [200 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 440 mg/1,000 kcal].

Analysis of Variance↗
PubMed1993

Effect of an n-3 fatty acid-deficient diet on the adenosine-dependent melatonin release in cultured rat pineal.

We studied the effect of a diet deficient in n-3 fatty acids on the adenosine-dependent melatonin release from cultured rat pineal gland after stimulation by 5'-N-ethylcarboxamidoadenosine (NECA), an A2 adenosine agonist. Experiments were conducted with 2-month-old rats raised on semipurified diets containing either peanut oil (n-3 deficients) or peanut plus rapeseed oil (controls). The proportion of docosahexaenoic acid (22:6 n-3) in the pineal total lipid fraction and in phosphatidylcholine and phosphatidylethanolamine was significantly decreased in n-3-deficient rats. This was compensated for partially by an increase in 22:4 n-6 and 22:5 n-6 levels. The activity of the cultured rat pineal, in terms of cyclic AMP content and N-acetylserotonin and melatonin release in the medium, was lower after stimulation by 10(-5) mol/L NECA in the group fed peanut oil than in the group fed peanut plus rapeseed oil. The increased ratio of n-6/n-3 fatty acids in pineal total lipids and the major glycerophospholipids (phosphatidylcholine and phosphatidylethanolamine) may have an important influence on the rat pineal responses. The results are discussed in the context of changes in membrane-bound proteins, including enzymes and/or receptors involved in the rat pineal gland function.

Adenosine↗
PubMed1993

Polyunsaturated fatty acid composition of human milk in France: changes during the course of lactation and regional differences.

Milk samples were collected 2-5, 15, 30, 60 and 90 days postpartum from 41 individual mothers recruited in three French cities in order to obtain a general view of the polyunsaturated fatty acid (PUFA) composition in France. Considering the overall results, linoleic acid (18:2 n-6) represented between 11.6% and 13% of total fatty acids in human milk. In contrast alpha-linolenic acid (18:3 n-3) accounted only for about 0.6%, and hence the 18:2 n-6 to 18:3 n-3 ratio was close to 20. Amounts of n-6 and n-3 long-chain PUFAs (LCPs) regularly decreased from postpartum days 2-5 (3.09%) to day 30 (1.67%), and then remained unchanged up to postpartum day 90; the n-6/n-3 LCP ratio ranged between 2.5 and 2. According to regional areas, there were significant differences (P < 0.05) only for colostrum contents of 18:3 n-3 and LCPs, the LCP ratio remaining unchanged. These data are discussed with regard to recent data on human milk fatty acid composition from Western countries and to the mechanisms involved in milk LCP balance.

Analysis of Variance↗
PubMed1993

Prolactin transit through mammary epithelial cells and appearance in milk.

In lactating mammary epithelial cells, prolactin (PRL) binds to its receptors, is endocytosed and carried to the milk. In order to study the transit of the hormone and its receptor respectively, the intracellular pathway of PRL and ot two monoclonal antibodies against PRL-receptor (PRL-R), labelled with biotin and colloidal gold, were monitored in incubated fragments of enzymatically dissociated mammary cells of lactating rabbits. PRL was internalised in endosomes and carried to microvesicular bodies, lysosomes, Golgi apparatus and secretory vesicles containing casein micelles. After 60 min of incubation at 37 degrees C, PRL was released in the incubation medium. M110 anti PRL-R was internalised in endosomes and detected mainly in microvesicular bodies during a one hour incubation. In contrast, A917 anti PRL-R also internalised in endosomes and in microvesicular bodies, was carried out to the Golgi apparatus and to the lumen of the acini after 5 min of incubation at 37 degrees C. These results suggest that an intracellular sorting occurs in the presence of the hormone or the different antibodies. The fatty acid composition of the mammary epithelial cell membranes influences the activity of these cells. To examine the effect of this membrane composition on the transit of PRL, the intracellular pathway of the hormone was studied in mammary cells of lactating rats previously fed with lipid deficient diets. Plasma levels of PRL were not modified in rats receiving a deficient diet compared to controls. Labelled PRL was accumulated inside the microvesicular bodies during a one-hour incubation at 37 degrees C. However, PRL was always detectable in milk, suggesting that the intracellular transit of PRL could be slowed down but not inhibited. Possible relationships between endocytosis of PRL and its secretagogue effect are discussed.

Animals↗
PubMed1993

[Contribution of magnetic resonance imaging to the exploration of the mediastinum].

Magnetic resonance imaging (MRI) already has a number of indications in exploration of the mediastinum, the most frequent of which being exploration of vascular pathologies facilitated by visualization of vascular lumina without need for a contrast medium, MRI can provide detailed information concerning the size, relations and wall thickness of these vessels ans sometimes of aneurysmal thrombosis. It also makes it possible to study aortic dissections and venous diseases of the mediastinum. As regards mediastinal masses, MRI complements computerized tomography (CT): it is better than the latter to distinguish vascular relations and it provides aetiological arguments based on the intensity of T1 and T2-weighted signals.

Adolescent↗
PubMed1993

[Magnetic resonance imaging of the respiratory airways and the pulmonary parenchyma].

In the study of the proximal airways, MRI is mainly appropriate for the trachea and the mainstem bronchi, in case of tracheal stenosis or tumors. CT remains the reference examination for the distal airways. In alveolar condensation, MRI may help differentiating some of the involved materials (blood, lipids). Lastly, the role of MRI is limited in interstitial pathology, even though some indications may be appearing: fibrosis following radiation therapy, determination of the inflammatory component.

Humans↗
PubMed1992

IL6 and acute phase plasma proteins in peritoneal fluid of women with endometriosis.

Several authors have documented signs of chronic inflammation in the pelvis of women with endometriosis. We investigated the possible involvement of interleukin 6 (IL6), an important regulator of inflammation and immunity, in minimal and mild endometriosis by measuring levels of IL6 and proteins (alpha 1-acid glycoprotein, alpha 1-antitrypsin, alpha 2-HS glycoprotein and albumin) the synthesis of which is regulated by IL6, in peritoneal fluid (PF) from infertile women with histologically confirmed endometriosis (stage I and II; n = 28) and from endometriosis-free fertile (n = 14) and infertile women (n = 13). Spontaneous and LPS-induced IL6 secretion by cultured PF macrophages from women with endometriosis (n = 12) and without endometriosis (n = 9) were also studied. No significant differences were observed in the concentrations of the four proteins studied. Immunoreactive IL6 was detected in all three groups, with no significant differences. In contrast, significantly higher levels of IL6 were released by both unstimulated (P = 0.01) and LPS-stimulated (P = 0.006) peritoneal macrophages from the women with endometriosis. We conclude that local IL6 synthesis by activated macrophages may play a role in the endometriosis process.

Acute-Phase Proteins↗
PubMed1992

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Journal Article↗
PubMed1992

Comparison of gas chromatographic-mass spectrometric methods for screening of chlorotriazine pesticides in soil.

The performance of a coupled technique resulting from the combination of gas chromatography with a selective mass spectrometric technique (tandem mass spectrometry) (GC-MS-MS) with collisionally activated dissociation (CAD) and multi-reaction monitoring (MRM) was compared with that of GC-low resolution MS (GC-LRMS) at a resolving power of 1000 and GC-high-resolution MS (GC-HRMS) at resolving powers of 5000 and 10,000 for the determination of atrazine, simazine, cyanazine, deethylatrazine and deisopropylatrazine in polluted soil samples. GC-MS-MS daughter ion spectra for the parent ions [M]+. and [M - CH3]+ were generated using collisionally activated dissociation and studied. Also, by optimizing the collision energy for maximum sensitivity a method for screening chlorotriazines by MRM was developed. Analyses of soil sample extracts showed that GC-MS-MS overcomes interferences from other chlorotriazines and interfering compounds that could not be removed by GC-HRMS or GC-LRMS at resolving powers of 10,000 and 1000, respectively. The limits of detection for GC-MS-MS and GC-HRMS at a signal-to-noise ratio of 10 ranged between 1 and 24 pg, with a mean relative standard deviation of 25-30%. Soil samples known to contain chlorotriazines and their degradation products were analysed by GC-MS-MS and the results obtained were compared with those given by GC-HRMS at resolving powers of 5000 and 10,000, with quantification differences of 25-30%.

Gas Chromatography-Mass Spectrometry↗
PubMed1992

Identical genetic locus for Baltic and Mediterranean myoclonus.

Genetic linkage analysis shows that Baltic and Mediterranean myoclonus, two forms of progressive myoclonus epilepsy, are closely linked to marker D21S113 on the long arm of chromosome 21. Baltic and Mediterranean myoclonus are most probably due to mutations of the same gene.

Alleles↗