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Biomedical subjects

G Faure

Publications and source records attributed to G Faure.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Natural inhibitors of toxic phospholipases A(2).

Endogenous proteins isolated from the serum of snakes have been found to be natural inhibitors displaying anti-hemorrhagic, anti-neurotoxic or anti-myotoxic activity. Some of these proteins inhibit phospholipase A(2) (PLA(2)) activity. We review in brief here the properties, structure and classification of these PLA(2) inhibitors (PLIs), focusing in particular on the mechanism of neutralization of the toxic PLA(2)s by anti-neurotoxic PLIs. We also discuss: 1) the protection provided by these molecules against endogenous snake venom PLA(2)s; 2) their specificity for neurotoxic snake venom PLA(2)s (beta-neurotoxins) and non-toxic mammalian secreted sPLA(2)s; and 3) the domains of the inhibitor and PLA(2) potentially involved in the binding of these two molecules. Purified and characterized natural inhibitors of PLA(2)s may be used to develop more effective therapeutic strategies for dealing with snake envenomation. Moreover, the structural and, in some cases, functional similarity of natural inhibitors to various mammalian proteins suggests that these mammalian proteins may themselves behave as PLA(2) inhibitors. Thus, these proteins may have important physiological functions in regulating the activities of neurotoxic PLA(2) and non-toxic sPLA(2).

Animals↗
PubMedDate not supplied

Expression of IL-2alpha and IL-2beta receptors on the membrane surface of human sperm.

Cytokines are secreted proteins that act as local immunological mediators. Increased seminal cytokine concentrations are associated with fertility problems. The purpose of the present study was to investigate the presence of IL-2alpha, and IL-2beta receptors on fresh and isolated sperm by flow cytometry and transmission electron microscopy. Twenty sperm samples from oligospermic men were incubated with CD25, a mouse monoclonal antibody specific for IL-2alpha-chain receptor, and CD122, a mouse monoclonal antibody specific for IL-2beta-chain receptor. The strong initial fluorescence intensity and, subsequently, a labeling index yielded by CD25 and CD122 decreased in sperm centrifuged on a Percoll gradient (p < .05). The expression of CD25 and CD122 correlated negatively with fresh sperm concentration, but in sperm centrifuged on a Percoll gradient there was no correlation. Labeling with CD25 and CD122 antibody was evident on the head and the middle piece in fresh sperm, while in sperm centrifuged on a Percoll gradient a weak labeling was observed only on the principal piece. The authors have identified and localized cytokine receptors on human sperm for the first time. Cytokine receptors may be involved in the regulation of pathophysiological events in sperm cell functions and male infertility. The exact pathway involved in modulation of these receptors requires further investigation. These results contribute to the understanding of cytokine-sperm relationships.

Flow Cytometry↗
PubMedDate not supplied

[Activated protein C resistance and cardiolipin antibodies in leg ulcers].

BACKGROUND: We conducted a prospective study to determine the prevalence of activated protein C resistance and anticardiolipin antibodies in leg ulcers, whatever venous, arterial or arteriovenous. PATIENTS AND METHODS: One hundred fifteen patients hospitalized for leg ulcers, without antiphospholipid syndrome were included. The vascular abnormalities were studied by clinical examination, Doppler, duplex Doppler and, when required, arteriography. Activated protein C resistance was isolated by a "classic" test (normalized APTT ratio in PCa presence or absence) and by a "second generation test" (by preliminary dilution with deficient factor V plasma). All patients with abnormal results on the second test were screened for the factor V Leiden (by PCR amplication with use of restriction enzymes). Anticardiolipin antibodies were investigated with an ELISA method with Harris standards as reference, in which the positive threshold was established at 20 units. RESULTS: Among these 115 patients, 50 venous (43.5 p. 100), 23 arterial (20 p. 100), 42 arteriovenous (36.5 p. 100) leg ulcers were identified. Activated protein C resistance was isolated in 12 cases (10.4 p. 100) (heterozygous carriers): 7 venous ulcers, 3 arteriovenous, 2 arterial. Anticardiolipin antibodies were measured at significant level in 49 cases (42.6 p. 100): 21 venous ulcers, 18 arteriovenous, 10 arterial. DISCUSSION: In this study, there was no statistical difference between the activated protein C resistance prevalence in leg ulcers when compared with Lorraine population (p=0.27). Factor V Leiden or anticardiolipin antibodies abnormalities were isolated in 56 cases (48.7 p. 100) without statistical difference between the 3 types of ulcers. Finally, the pathophysiology of venous, arterial and arteriovenous leg ulcers remains complex, suggesting several coagulation perturbations.

Activated Protein C Resistance↗
PubMedDate not supplied

Lymphocyte subpopulations in an experimental model of axial and peripheral enthesiopathies.

We report a study of lymphocyte subsets in experimental arthritis induced in Wistar Furth rats by native human type II collagen and muramyl dipeptide. This experimental arthritis shares similarities with both the spondyloarthropathies and rheumatoid arthritis. Peripheral blood T lymphocytes, primarily the CD4+ cells (p = 0.01), were lower in arthritic rats than in the controls, although the difference in the CD4/CD8 ratio was not statistically significant. Splenic CD4 cells were significantly (p = 0.03) more numerous in arthritic rats, while the numbers of MHC class II positive cells (p = 0.002) and kappa-bearing B-cells (p = 0.0004) were significantly lower. Determination of peripheral blood and spleen lymphocytes subsets could therefore be used for the assessment of arthritis and for the evaluation of therapeutic agents. Thymic T-cell differentiation does not appear to be impaired in this model. These results differ from the peripheral blood disturbances described in the active stages of human rheumatoid arthritis and are more similar to those reported in ankylosing spondylitis patients. However, the absence of alterations in the Peyer's patches suggests that pathogeneic mechanisms involving mucosal areas and exogenous intestinal antigens are not reproduced in this model.

Acetylmuramyl-Alanyl-Isoglutamine↗