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Biomedical subjects

D Léger

Publications and source records attributed to D Léger.

33 records · Page 2Linked to original sources
PubMed1994

Change in glycosylation of chicken transferrin glycans biosynthesized during embryogenesis and primary culture of embryo hepatocytes.

Transferrins were isolated by immunoaffinity chromatography from chicken serum, chicken embryo serum and from the culture medium of chicken embryo hepatocytes in primary culture. The glycovariants of these three transferrins were separated by ion-exchange chromatography using a fast protein liquid chromatography (FPLC) system. The structures of the oligosaccharide-alditols released by hydrazinolysis from the glycovariants were compared after analysis by a combination of methanolysis, methylation analysis and 1H-NMR spectroscopy. In the three transferrins analysed, the oligosaccharides were of the biantennary N-acetyllactosaminic type, having several prominent features. In particular, the embryo serum transferrin glycan differed from that of chicken serum transferrin by the presence of a bisecting N-acetylglucosamine, suggesting a developmental change in glycosylation. The glycan structure of the transferrin secreted by the embryo hepatocytes in primary culture was marked by the presence of fucose (alpha 1-6) linked to the core N-acetylglucosamine, suggesting that expression of the fucosyltransferase activity is dependent on cell culture conditions. Moreover, comparative analysis of chicken serum transferrin and ovotransferrin glycans reinforces the idea that the glycosylation of two identical polypeptide chains is organ specific.

Animals↗
PubMed1992

[Campaign against allergenic moulds in dwellings. Inhibitor properties of essential oil of Geranium 'Bourbon', citronellol, geraniol and citral].

Many fungal airborne spora show allergenic effects. Indoor (dwelling, work rooms, hospital chambers) can be disinfected by elimination of living particles. We have undertaken experiments in more and more spacious bulks for evaluation of the antifungal effects of vapours of essential oils and some volatiles compounds. Results show that the Mucorales and Geotrichum resist strongly. On the contrary, the Cladosporium strains, some Aspergillus and Penicillium, Trichothecium roseum are the most sensitive, specially towards the citral vapours. Experiments in hospital can be undertaken.

Acyclic Monoterpenes↗
PubMed1992

[Effect of aging on schizophrenia].

The problem of the senescence's influence on schizophrenia and the right to detach this variable from those who take care of temporal evolution is complicated. From a population of 99 schizophrenic patients (DSM III criteria's) having most of 60 year old and most of 20 years schizophrenia's disease evolution; we have study the whole or partial imputability to the senescence of residential statute's modification; frequency, reason, duration of hospitalization's change, psychotic's symptom levelling; and therapeutic's instability.

Activities of Daily Living↗
PubMed1990

[Fungal spores in the atmosphere at Besançon, France: seasonal and annual variations during 1988 and 1989].

Airborne spora in the atmosphere of Besançon were weekly determined, searching links between appearance of species and seasonal allergies. By comparison of the results of the two years, it is easy to see many variations. At first, the number of colonies collected is very different, 2,990 colonies in 1988, 9,841 in 1989. During 1989, some genera are present in greatest quantities. It is the case of Cladosporium and Epicoccum in summer and Aspergillus in autumn. For the allergologists, Alternaria, very abundant during 1989, is perhaps the outstanding incident, this genus being considerated as very allergenic.

Atmosphere↗
PubMed1989

Presence of fucosylated triantennary, tetraantennary and pentaantennary glycans in transferrin synthesized by the human hepatocarcinoma cell line Hep G2.

Transferrin synthesized by a human hepatocellular carcinoma cell line Hep G2 (called Hep G2 transferrin) was purified from culture media by immunoaffinity chromatography on a rabbit anti-(human serotransferrin) IgG column. The eluted transferrin was then resolved into five peaks on a cation-exchange column using the fast protein liquid chromatography system. The major fraction, named Hep G2 transferrin fraction C, having a molecular mass of 82.5 kDa was found to be homogeneous in polyacrylamide gel electrophoresis and in concanavalin-A-affinity crossed immunoelectrophoresis. A comparative analysis of the molar carbohydrate composition of normal human serotransferrin and of Hep G2 transferrin fraction C shows an increase in the latter in the number of galactose and N-acetylglucosamine residues and in the presence of fucose, which is absent in normal transferrin. By a combination of methylation analysis and NMR spectroscopy, the primary structure of the oligosaccharide alditols released from Hep G2 transferrin fraction C by reductive alkaline cleavage has been established as triantennary, tetraantennary and pentaantennary N-acetyllactosaminic structures with fucose residues (alpha 1-3)-linked to peripheral N-acetylglucosamine residues. These results indicate that the increase in the number of antennae in transferrin glycans synthesized by the hepatocarcinoma cell line is much more pronounced than in liver diseases such as alcoholic cirrhosis and that, in addition, the malignant transformation of human liver induces the presence of fucose.

Carbohydrate Conformation↗
PubMed1989

Physiological significance of the marked increased branching of the glycans of human serotransferrin during pregnancy.

Human serotransferrin (Tf) presents a microheterogeneity based on the existence of biantennary and triantennary glycans of the N-acetyl-lactosaminic type. By affinity chromatography on a concanavalin A-Sepharose column in well-defined conditions, human serotransferrin isolated from healthy donors was resolved into three carbohydrate molecular variants: Tf-I (less than 1%), Tf-II (17 +/- 2%) and Tf-III (82 +/- 3%) containing two triantennary glycans, one triantennary and one biantennary glycans and two biantennary glycans respectively. In addition, two 'isomers' of the triantennary glycans containing the third antenna beta-1,4-linked to the alpha-1,3-mannose residue or beta-1,6-linked to the alpha-1,6-mannose residue were characterized by methylation analysis in the ratio 1:1 in both Tf-I and Tf-II variants. On concanavalin A crossed immuno-affinity electrophoresis, the patterns exhibited by each of the three purified variants or by a mixture of these variants were compared with the patterns given by transferrin present in sera from nonpregnant and pregnant women. The results suggest that the relative proportions of transferrin carbohydrate variants was unchanged when the concentration of transferrin was increased in serum from normal donors, whereas in the serum of pregnant women, especially in the last 3 months of pregnancy, when the serum concentration of transferrin reached 4.5-5 g/l, the relative proportions of the carbohydrate variants Tf-I and Tf-II increased from 1 to 6 +/- 1% and from 17 +/- 2 to 26 +/- 3% respectively while that of Tf-III decreased from 82 +/- 3 to 67 +/- 3%. The binding of the three transferrin carbohydrate variants to the receptor of the syncytiotrophoblast plasma membranes was determined by using Scatchard-plot analysis. The number of binding sites remained constant with an increase in the number of triantennary glycans whereas a decrease up to 6-fold in the affinity constant was observed. Detection of the transferrin-receptor complex by immunoblotting in the presence of non-dissociating detergents revealed the existence of only one type of receptor or of a receptor possessing similar properties involved in the binding of each of the three serotransferrin carbohydrate variants.

Female↗
PubMed1988

Platelet serotonin content and plasma tryptophan in peri- and postmenopausal women: variations with plasma oestrogen levels and depressive symptoms.

Platelet serotonin content was measured by high pressure liquid chromatography in 56 peri- and postmenopausal women, in order to study variations of this parameter with hormonal status and depressive mood symptoms. Clinical symptoms were assessed by a self-report depression symptom scale (CES-D of NIMH). Thirty-eight women with a score of 16 or more were considered as presenting depressive symptoms (mean score +/- SD = 28.8 +/- 10.5), while the others formed the control group (n = 18, score = 4.4 +/- 4.2). Platelet serotonin contents were significantly lower in the 'depressed' group (0.302 +/- 0.010 vs. 0.366 +/- 0.020 nmol 10(-8) platelets, means + SEM, P less than 0.001 by Mann-Whitney U-test). In 'depressed' women who had been treated for one or more depressive episodes, platelet 5-HT contents (0.283 +/- 0.023, n = 18, P less than 0.01) were significantly lower with respect to controls. In patients without previous episodes of depression, serotonin expressed in nmol 10(-8) platelets did not differ significantly from controls but serotonin expressed in nmol ml-1 of blood was slightly lower than control values (0.890 +/- 0.085, n = 20 vs. 1.088 +/- 0.090 nmol ml-1, n = 18, P less than 0.02). Platelet serotonin content was positively correlated to plasma oestrone and oestradiol concentrations among the control group but not in the 'depressed' group.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1985

Inhibition of some activities of thrombin by a collagen-derived octapeptide.

The effect of a collagen-derived octapeptide on some properties of thrombin is presented. This peptide provoked a dose- and time-dependent prolongation of the thrombin-induced plasma and fibrinogen clotting time and inhibited the polymerization of fibrin generated from fibrinogen by thrombin. It did not affect the polymerization of fibrin monomers; it was also without effect on the coagulation of plasma or fibrinogen by reptilase. The prolongation of the fibrinogen clotting time depended on the duration of the incubation of thrombin and the octapeptide and not on the duration of the incubation of fibrinogen and the octapeptide. The inhibition was therefore ascribed to an interference with thrombin, rather than with fibrinogen. A preincubation of the octapeptide with thrombin resulted in an inhibition of the thrombin-induced platelet aggregation. The effect of the octapeptide on thrombin has been related to the presence of positively and negatively charged groups, because uncharged analogue sequences were without effect on these activities of thrombin.

Adult↗
PubMed1979

[The outcome in pregnancies resulting after the induction of ovulation 519 pregnancies (author's transl)].

Some geneticists have been against induction of ovulation because there is a greater incidence of chromosome abnormalities in spontaneous abortions that occur after induced pregnancies. We have found the number of early abortions (15.6 p. 100) and of malformed fetuses (4.8 p. 100) is not greater than average when we have studied a personal prospective series of 140 pregnancies and a series of 519 pregnancies collected following an enquiry made among some of our colleagues. The number of late abortions and of premature labours is much higher (3.4 p. 100 and 14.8 p. 100 respectively) and they correspond particularly with the higher incidence of multiple pregnancies (12.3 p. 100) which have been obtained especially after the use of HMG. This has a direct repercussion on perinatal mortality (4.3 p. 100).

Abortion, Spontaneous↗
PubMedDate not supplied

SF-36: evaluation of quality of life in severe and mild insomniacs compared with good sleepers.

OBJECTIVE: Despite many studies, the impact of chronic insomnia on daytime functioning is not well understood. The aim of our study was to detect this impact by evaluating quality of life (QoL) using a validated instrument, the 36-item Short Form Health Survey of the Medical Outcomes Study (SF-36), in three matched groups of severe insomniacs, mild insomniacs, and good sleepers selected from the general population. METHODS: Three matched groups of 240 severe insomniacs, 422 mild insomniacs, and 391 good sleepers were recruited from the general French population after eliminating those with DSM-IV criteria for anxiety or depression. All subjects were asked to complete the SF-36. Scores for each QoL dimension were calculated and compared statistically among the three groups. RESULTS: Severe insomniacs had lower QoL scores in eight dimensions of the SF-36 than mild insomniacs and good sleepers. Mild insomniacs had lower scores in the same eight dimensions when compared with good sleepers. No dimension was significantly more altered than the other. CONCLUSIONS: The mental health status and role of emotional QoL dimensions were worse in severe and mild insomniacs than in good sleepers. This result held even though we screened for psychiatric diseases, which shows a clear interrelation between insomnia and emotional state. General health status was also worse in severe and mild insomniacs than in good sleepers. However, we could conclude only that insomnia was related to a worse health status and not whether it was a cause or consequence of this worse health status. Finally, the degradation of QoL scores was correlated with the severity of insomnia.

Adolescent↗
PubMedDate not supplied

[Mechanisms of diurnal hypercapnia in sleep apnea syndromes associated with morbid obesity].

OBJECTIVES: The prevalence and mechanisms of diurnal hypercapnia in subjects with sleep apnea syndrome are not well known, particularly in the morbidly obese. METHODS: We studied a group of 24 subjects with sleep apnea syndrome and morbid obesity defined as a body mass index greater than 40 kg/m2 and free of chronic respiratory disease. RESULTS: Hypercapnia (PaCO2 > 42 mmHg) was found in 50% of the subjects. Age, body mass index, waist/hip ratio, apnea index, ratio of maximum forced expiratory volume in one second (FEV1) to vital capacity and expiratory reserve volume were not significantly different between hypercapnic and normocapnic subjects. Total pulmonary capacity, vital capacity and FEV1 were significantly lower in hypercapnic subjects than in normocapnic subjects. CONCLUSION: These findings suggest that ventilatory restriction plays an important role in the development of diurnal alveolar hypoventilation in subjects with sleep apnea syndrome and morbid obesity.

Adult↗