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Biomedical subjects

V Maréchal

Publications and source records attributed to V Maréchal.

24 records · Page 2Linked to original sources
PubMed1993

Continuous systemic secretion of a lysosomal enzyme by genetically modified mouse skin fibroblasts.

Lysosomal enzymes secreted or externally supplied into the extracellular medium can be internalized by cells and targeted to lysosomes after binding to specific membrane receptors. This process allows for the replacement of the missing enzyme activity in deficient cells. Using a retroviral vector, we have introduced the human beta-glucuronidase cDNA into primary mouse skin fibroblasts. The genetically modified cells were then engrafted into neo-organs that had been previously implanted into the peritoneal cavity of syngeneic recipient mice. The hypervascularized structures, made of collagen and basic fibroblast growth factor-coated synthetic fibers embedded into extracellular matrix gel, allowed in vivo survival of engrafted fibroblasts that expressed the human beta-glucuronidase cDNA for at least 3 months. The human enzyme was detected in the liver, lung, and spleen of experimental animals, but became undetectable after removal of the neo-organ. This observation indicated that the human enzyme was secreted into the serum and then captured by distant organs. The use of genetically modified fibroblasts implanted into neo-organs may, therefore, represent a convenient approach to enzyme replacement therapy in lysosomal storage diseases.

3T3 Cells↗
PubMed1988

Inactivation and partition of human immunodeficiency virus during Kistler and Nitschmann fractionation of human blood plasma.

We studied the inactivation of the etiologic agent of the acquired immunodeficiency syndrome, human immunodeficiency virus, in the course of the Kistler and Nitschmann cold ethanol fractionation of human blood plasma. By measuring reverse transcriptase activity and viral infectivity, we have shown that the virus load is reduced by a factor of 10(4) during the initial and at least a factor of 10(6) during the subsequent steps of the fractionation procedure. This loss of virus may be observed in the absence or in the presence of antibodies against human immunodeficiency virus and is due to a combination of chemical inactivation, physical partition, and injury caused by repeated freezing and thawing. The laboratory data therefore further confirm epidemiological studies which indicate that immunoglobulin preparations obtained by ethanol fractionation do not transmit human immunodeficiency virus.

Chemical Fractionation↗
PubMedDate not supplied

Enzyme-linked immunosorbent assay for antibodies to ZEBRA, an Epstein-Barr trans-activator.

Patients with AIDS and AIDS-related complex often show symptoms of Epstein-Barr virus (EBV) reactivation. Several EBV-encoded trans-acting factors activate the EBV lytic cycle, and one, called ZEBRA (BamHI Z EBV replication activator), controls the switch of EBV from a latent to a productive cycle. We describe here a simple ELISA test using a bacterially expressed ZEBRA protein as antigen. Utilizing this technique, we evaluated the humoral response to ZEBRA antigen in 38 patients with nasopharyngeal carcinoma and 134 subjects with an asymptomatic HIV 1 infection. The control group consisted of 40 healthy adult blood donors.

Antibodies, Viral↗
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

[Epstein-Barr virus].

Epstein-Barr Virus (EBV) is the prototype member of the human herpesvirus subfamily Gammaherpesviridae. EBV establishes a latent infection in lymphoïd cell and replicates in epithelial cells. Infection of individuals with EBV is widespread in all human populations, as shown by the high proportion of individual with specific antibodies in their serum. EBV is the etiological agent of the infectious mononucleosis and has been implicated in the pathogenesis of an increasing number of human malignancies, the best characterized being endemic Burkitt's lymphomas, nasopharyngeal carcinomas (NPC), and polyclonal lymphomas in immunocompromised patients. EBV infection in vivo is a complex mixture of latent, reactivated, transforming, or replicative type of infection. EBV infection is characterized by sporadic viral excretion in the oropharynx and persistent latent infection in the bone marrow and peripheral blood lymphocytes. EBV infection includes an intense immune response. During primary infection, the humoral response is primarily directed toward antigens of the lytic cycle, membrane antigen complex, early antigen (EA), viral capsid antigen (VCA) while the antibodies response to EBNAs is delayed. The cell mediated response controls the proliferation of EBV-infected lymphocytes through two classes of cytotoxic cells, namely, natural killer and T8 cytotoxic cells. Laboratory diagnosis of EBV infection is recently based upon molecular biology techniques which provides a useful tool for direct identification of EBV and may allow to better understand the role of the virus in the pathogenesis of EBV associated disorders.

Antibody Formation↗