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M-P Vasson

Publications and source records attributed to M-P Vasson.

8 recordsLinked to original sources
PubMed2006

Potential anti-inflammatory effects of Melaleuca alternifolia essential oil on human peripheral blood leukocytes.

The fungicidal and bactericidal actions of the essential oil (EO) of Melaleuca alternifolia seem well established, but their anti-inflammatory and antioxidative effects remain unclear. This study investigated in vitro the possible role of whole Melaleuca alternifolia EO as a modulator of the inflammatory/non-specific immune response by exploring the chemotaxis and kinetic radical oxygen species (ROS) production of leukocytes and cytokine secretion in peripheral blood mononuclear cells (PBMCs) in humans. The influence of Melaleuca alternifolia EO on the chemotaxis under agarose of isolated neutrophils (PMNs) was evaluated. The kinetics of ROS production by stimulated total circulating leukocytes was followed over 2 h by recording the fluorescence intensity of oxidized dihydrorhodamine 123. The effects of this EO on pro-(interleukin IL-2) and anti-(IL-4 and IL10) inflammatory cytokine secretions were determined by ELISA following incubation of PBMCs with the EO for 24 h. Melaleuca alternifolia EO was inefficient on the chemotaxis of PMNs. It exerted an antioxidant effect, reducing ROS production throughout the kinetic study. Melaleuca alternifolia EO inhibited PBMC proliferation, as revealed by a reduction in IL-2 secretion by stimulated lymphocytes. This EO at 0.1% directly increased the secretion of the anti-inflammatory cytokine IL-4 compared with IL-4 secretion without EO (18.5 +/- 10.0 vs 3.3 +/- 1, p < 0.05), and also increased IL-10 secretion at 0.01% (94.9 +/- 38.7 vs 44.1 +/- 18, ns). Melaleuca alternifolia EO may not only act as an anti-inflammatory mediator through its antioxidant activity but may also efficiently protect the organism by reducing the proliferation of inflammatory cells without affecting their capacity to secrete anti-inflammatory cytokines.

Anti-Inflammatory Agents↗
PubMed2005

Leptin: a proliferative factor for breast cancer? Study on human ductal carcinoma.

Mammary adipose tissue is an important source of paracrine mitogens and anti-mitogens, including insulin-like growth factor, transforming growth factors, and cytokines (especially, TNFalpha and IL-1beta). Nevertheless, it is also an important source of the adipocytokine, leptin. Recently, leptin was reported to stimulate the proliferation of various cell types (pancreatic beta cells, prostate, colorectal, lung, etc.) as a new growth factor. It was also shown to stimulate the proliferation of breast cancer cell lines. In this study, we conducted an immunohistochemical analysis of leptin expression in normal tissue and benign and malignant ductal breast cell, representing the different states of the invasion process. We determined for the first time that leptin is expressed both by ductal breast tumors and by benign lesions as atypical hyperplasia. This suggests that leptin may be taken up or synthesized by all modified ductal breast cells, and may prove a proliferative factor. Moreover, leptin is unexpressed by normal tissue in the healthy breast but is exhibited by the normal tissue in near vicinity of the malignant ductal breast lesions. We also postulated that leptin may be a prognostic or diagnostic factor for ductal breast cancer. These putative hypotheses require further study.

Adult↗
PubMed2005

Troglitazone reduces leptinemia during experimental dexamethasone-induced stress.

BACKGROUND AND AIMS: Recently, we found that profound anorexia observed in a catabolic model induced by chronic glucocorticoid (dexamethasone, Dex) injection could be associated with strong hyperleptinemia. To investigate the implication of leptin in this catabolic stress response, we used a model whereby leptin secretion was inhibited using troglitazone (Trg) concomitantly with a Dex-induced-stress injection. METHODS: Adult rats (3 months, n=12) were stressed with a Dex injection (1.5 mg/kg/day ip, 5 days) and either treated (DXTG+, n=6) or not (DXTG-, n=6) with Trg (60 mg/kg/day sc, 5 days). These DXTG+ and DXTG- groups were compared with an untreated ad libitum group and a pair-fed group receiving saline ip instead of the Dex injection. The effects of troglitazone treatment on leptin gene expression in adipose tissue, blood glucose, insulin, and on hepatic parameters under stress conditions were determined. RESULTS: Trg treatment specifically diminished leptinemia (30%, DXTG+ vs DXTG-, p<0.05). Insulinemia and glycemia remained unchanged, as did leptin gene expression; food intake improved, but hepatic capacities did not show any alteration. CONCLUSION: Trg is a useful agent in exploring certain potential effects of leptin on metabolic and immune disorders occurring during aggression.

Adipocytes↗
PubMed2004

In vivo evidences that insulin regulates human polymorphonuclear neutrophil functions.

Polymorphonuclear neutrophils (PMN) are able to destroy invasive mircoorganisms by a wide variety of functions. Whereas insulin does not stimulate hexose transport in PMN, previous reports have clearly shown that this hormone regulates glucose metabolism inside this cell, raising the question of insulin action on PMN functions in humans. It is interesting that in vitro studies established a strong relationship between specific binding of insulin to its PMN membrane receptor and the activation of the main PMN functions. Therefore, investigation in healthy subjects under strict euglycemia and physiological insulinemia was performed to understand the in vivo-specific action of insulin on PMN functions without hyperglycemia interferences. We determined numerous PMN functions before and after hyperinsulinemia (0.5 mU/kg/min) and euglycemia (0.9 g/l) clamp for 4 h in eight adult healthy volunteers (24+/-6 years). The total number of PMN and the number of PMN expressing CD11b, CD15, CD62L, and CD89 were significantly increased over baseline (P<0.001), whereas the density of these receptors was down-regulated (P<0.01) by insulin. PMN chemotaxis (+117%, P<0.05), phagocytosis (+29%, P<0.001), and bactericidal (+17-25%, P<0.001) capacities were increased during the insulin clamp (P<0.05). Therefore, insulin treatment may modulate PMN functions not only by attainment of a better metabolic control, as suggested by in vivo studies in diabetic patients, but also through a direct effect of insulin.

Adolescent↗
PubMed2002

Transglutamines and endocrine system (minireview).

Transglutaminases catalyze the posttranslation modification of proteins by catalyzing Ca2+ dependent acyl-transfer reaction resulting in the formation of new g-amide bonds between g-carboxamide groups of peptide-bound glutamine residues and various primary amines. Such glutamine residue serves as acyl-donor and the most common acyl-acceptors are e-amino groups of peptide-bound lysine residues or primary amino groups of some naturally occurring polyamines, like putrescine or spermidine. The active site of cysteine reacts first with the g-carboxamide group of glutamine residue to form the acyl-enzyme intermediate under the release of ammonia. In the second step, the complex reacts with a primary amine to form an isopeptide bond and liberate the reactivated enzyme. The presence of transglutaminases has been observed in various endocrine glands such as human pituitary, which was investigated by immunohistochemical methods using specific antibodies. A significant increase in the expression and activity of tissue transglutaminase was observed during involution of thymus. In the genital tract of the male rat two different forms of the enzyme transglutaminase could be identified and characterized. the presence of p53 and tissues transglutaminase gene expressions in human normal and pathologic adrenal tissues. The Ca2+-responsive enzyme transglutaminase, which catalyzes the cross-bridging of proteins, was found in pancreatic islet cells.

Animals↗
PubMed2002

Ultrastructural localization of binding sites for PNA and VVA-B(4) lectins in human breast cancer cell lines detected by confocal fluorescence microscopy.

Three cancer cell lines (MCF-7, HBL-100, MDA-MB 231) and subnormal breast epithelial cell line MCF-10A were labeled with FITC-conjugated VVA-B4 lectin, specific for D-GalNAcalpha-O-ser/thr, matching the structure of Tn antigen sugar residues, and with RTIC-conjugated PNA lectin, specific for DGalbeta1-3GalNAc-O-ser/thr, corresponding to the structure of T antigen. Simultaneous expression of Tn and T antigens on the same cells (but in widely differing proportions) led to their large heterogeneity and occurrence of numerous cell subpopulations within each of the studied cell lines. This observation proved that the changes leading to the formation of Tn antigen are not caused by an irreversible genetic mutation of beta1-3-galactosyltransferase. Expression of Tn antigen on MCF-10A cells with normal (or subnormal) karyotype suggests that the process of malignant transformation of the cell begins with the changes in molecular structure of glycoconjugates.

Antigens, Tumor-Associated, Carbohydrate↗