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Biomedical subjects

V Lambert

Publications and source records attributed to V Lambert.

At least 55 records · Page 3Linked to original sources
PubMed1997

Immortalization of caprine fibroblasts permissive for replication of small ruminant lentiviruses.

OBJECTIVE: To establish immortalized caprine fibroblastic cell lines permissive for replication of small ruminant lentiviruses. ANIMALS: Carpal synovial membrane explants collected aseptically from a surgically delivered fetus of a lentivirus-seronegative goat. PROCEDURE: Immortalization of goat embryonic fibroblasts was performed by DNA transfection with plasmids coding for simian virus 40 large T antigen. The generated cell lines were phenotypically characterized. Cytogenetics, growth pattern, and sensitivity to viral infection were studied. RESULTS: 3 cell lines, designated TIGEF, mMTSV-54, and mMTSV-93, were generated. They had a more rapid doubling time than did fibroblasts from which they were derived, and retained morphologic and phenotypic fibroblastic characteristics. They were immortalized but not transformed because tumor formation was not promoted after their s.c. injection into athymic nude mice. The 3 cell lines were susceptible to caprine arthritis-encephalitis virus and visna-maedi virus infections, and supported a complete virus replication cycle. CONCLUSIONS: Cultured caprine fibroblastic cells were immortalized, using simian virus 40 large T antigen. The TIGEF, mMTSV-54, and mMTSV-93 immortalized cell lines were permissive to in vitro small ruminant lentivirus replication. CLINICAL RELEVANCE: Because lentivirus detection, as well as detailed studies of host-lentivirus interactions, are hampered by differences in viral susceptibility of each primary culture, permanent cell lines are essential tools for such analysis.

Animals↗
PubMed1996

Midterm results after surgical repair of the anomalous origin of the coronary artery.

BACKGROUND: Immediate results after surgical repair of the anomalous origin of the coronary artery are well known, but few studies reported midterm results in a relatively large population. METHODS AND RESULTS: Between 1980 and 1995, 39 consecutive patients with anomalous origin of the coronaries artery from the pulmonary artery had restoration of a two-coronary-artery system. Median age at surgery was 18.5 months (range, 2.7 months to 38 years). Left ventricular (LV) function was normal in 13 patients. Direct aortic implantation was performed in 34 patients (87%), associated with mitral valvuloplasty in 3 patients. Hospital death occurred in 5 patients (13%; 70% confidence limits [CL], 8 to 20). Two patients were lost to follow-up. Mean follow-up was 40 +/- 42 months. There was no late death after 1 month, and the survival rate was 84% (70% CL, 67 to 93). One patient had a mitral valvuloplasty 18 months after reimplantation. At the last follow-up, LV shortening fraction (SF) was normal in 86% (70% CL, 61 to 96), but LV dilation persisted in 73% of patients, and 12 of the survivors (39%) had abnormal regional wall motion of the left ventricle. A perfusion defect with incomplete redistribution was observed in 8 patients on thallium-201 imaging performed in 45% of survivors. Total mortality was related only to the preoperative SF: 12% versus 24.8% (P < .05). No factor was related to SF recovery. CONCLUSIONS: Despite no late deaths and SF recovery, LV dilation and ischemic segments of the left ventricle persisted at the long-term follow-up.

Adolescent↗
PubMed1996

Ultrastructural modifications in cultured fetal quail hepatocytes exposed to pesticides and PCBs.

There is increasing interest in cultured hepatocytes as a tool for solving toxicological and pharmacological problems while reducing laboratory animal experimentation. In the present study, fetal hepatocytes from the Japanese quail (Coturnix coturnix japonica) were used as an in vitro alternative model for evaluating the effects of PCBs and various pesticide-type chemicals on cell ultrastructure. Major alterations were demonstrated. The most striking effects of toxicants were an increase in the number of cisternae of the rough endoplasmic reticulum (RER), various alterations of mitochondrial morphology, a decreased glycogen content, vacuolization of the cytoplasm, and the appearance of concentric membrane arrays (CMA's), also called myelin-like figures. Other changes were sometimes observed, such as altered cell junctions, an increased lipid content, deformations of the nuclei, or the appearance of crystalline structures. These ultrastructural modifications seem to be dose-dependent. The present in vitro findings are validated by similar observations previously made in vivo on Japanese quail. They confirm the effectiveness of this technique as a biomonitoring tool for the evaluation of environmental quality. Yet the multiplicity of possible toxic effects, even for xenobiotics of a same category, makes it necessary to screen additional indicators of toxicity, such as the detoxifying activity of monooxygenases.

Animals↗
PubMed1996

Correlation between P450 CYP1A1 inducibility, MspI genotype and lung cancer incidence.

The aim of this study was to verify a possible correlation between CYP1A1 induction, MspI genotype and lung cancer incidence. A case-control study was performed on 48 lung cancer patients and 81 healthy subjects to test the existence of a correlation, within a European population. The hyperinducible group exhibited a significantly higher risk of lung cancer (odds ratio = 3.41; P = 0.036), especially for adenocarcinoma (odds ratio = 5.29; P = 0.033). In contrast with the situation observed in Asian populations, the frequency of the M2 allele did not differ significantly in the total lung cancer population (7.82%) and the group of healthy subjects (10.71%). The median inducibility value was slightly higher among cancer patients with one or two M2 alleles than among patients homozygous for the wild-type allele (P = 0.09). However, the percentage of individuals possessing at least one mutated allele was not significantly higher among hyperinducible patients (37.5%) than among non-hyperinducible patients (16.0%). No significant correlation could be found between M2 allele and lung cancer or between M2 allele and CYP1A1 inducibility; the only positive correlation found was between CYP1A1 hyperinducibility and lung cancer incidence. Our observations do not support the view that the presence of the M2 allele at the MspI site of the CYP1A1 gene constitutes a significant lung cancer risk in Caucasians.

Age Factors↗
PubMed1994

Identification of major antigenic domains of duck hepatitis B virus pre-S protein by peptide scanning.

Neutralization epitopes of duck hepatitis B virus (DHBV) have been previously mapped within the N-terminal portion of the pre-S protein using monoclonal antibodies. However, the immune response of ducks to this region is not well characterized at the amino acid level. To this end, we have immunized adult Pekin ducks with either DHBV positive serum or bacterially expressed DHBpre-S polypeptide representing the N-terminal portion of the DHBV pre-S region. We have demonstrated that adult ducks inoculated with either antigen developed antibodies to the DHBV pre-S region starting 5 to 10 days postinjection. The sera of all ducks, irrespective of the immunogen used, exhibited a significant protective activity against DHBV, as assessed in vivo. To identify which pre-S domains bind antibodies from these duck sera, we have used the Pepscan methodology with overlapping octapeptides spanning the DHBV pre-S sequence from amino acids 1 to 145. Using this approach, five major antigenic domains, 7KSMDVRRI14, 22NQLAGRMIP30, 58TLQNQGAW65, 71RRVGLSNPT79, and 127GDDPLLGNQ135 were identified within the DHBV pre-S region.

Amino Acid Sequence↗
PubMed1994

Hepatitis C virus among blood donors: follow-up study.

BACKGROUND: The exact significance of antibodies to hepatitis C virus (HCV) in blood donors remains unknown. Confirmatory tests of anti-HCV-reactive serum and HCV RNA by polymerase chain reaction (PCR) are used to refute a large proportion of false-positive results. STUDY DESIGN AND METHODS: Ninety-two blood donors who were anti-HCV reactive in a first-generation enzyme-linked immunosorbent assay (ELISA) were reevaluated 10 months later with a second-generation ELISA (ELISA-2) as well as with second-generation recombinant immunoblot assay (RIBA-2) and by PCR. RESULTS: Twenty-five (43.9%) of the 57 ELISA-2-positive donors were confirmed as positive by RIBA-2; of these, 84 percent were HCV RNA positive in PCR. Of the 57 who were still anti-HCV positive, 46 were followed up and tested again in the same manner 2 years after the first screening. At that time, the pattern was little changed: 94 percent of RIBA-2- and PCR-positive donors remained positive. Of RIBA-2- and PCR-positive blood donors, 62 percent had abnormal alanine aminotransferase levels in at least one of the three evaluations. Among the anti-HCV-positive donors confirmed by RIBA-2, 60 percent, versus 12.6 percent in the control group, had a significantly (p < 0.001) more frequent risk factor for HCV infection, due to parenteral exposure to blood. CONCLUSION: These data confirm a good correlation between RIBA-2 reactivity and the detection of HCV RNA in a population of anti-HCV-positive blood donors.

Blood Donors↗
PubMed1994

Serological responses to different genotypes of hepatitis C virus in France.

The relationship between hepatitis C virus (HCV) genotypes and antibody status was studied in 104 chronic non-A, non-B hepatitis patients and asymptomatic HCV-infected blood donors. On the basis of amplification of the nonstructural protein 3 (NS3) coding region by PCR and hybridization with specific probes, 55 and 42 patients were identified as being infected with type I and type II, respectively, according to the classification by H. Okamoto, K. Kurai, S. Okada, K. Yamamoto, H. Lizuka, T. Tanaka, S. Fukuda, F. Tsudaand, and S. Mishiro (Virology 188:331-341, 1992). All samples were tested for antibodies to 5.1.1, C-100, C-33, and C-22 proteins by a second-generation recombinant immunoblot assay. Among 97 patients with known HCV genotypes, 31 of 42 patients infected with type II and 24 of 55 infected with type I had antibodies against all four antigens (P < 0.01). In the type II-infected group, more patients had detectable antibodies to 5.11, C-33, and C-22 proteins than in the type I group (P < 0.05). No difference was found in the serological response to C-100 between the two groups.

Base Sequence↗
PubMed1994

[Pulmonary atresia with open septum: analysis of therapeutic management apropos of 47 cases].

Pulmonary atresia with ventricular septal defect (VSD) accounts for 2% of all congenital heart disease. The prognosis is poor (30% survival at 1 year) and early medico-surgical management is essential. A natural history of retrospective analysis of 47 consecutive patients with this abnormality born between 1962 and 1992, hospitalised between 1971 and 1992 and followed up for an average of 9.6 years (range: 1 month to 24 years) allowed identification of several anatomical groups: Group I (N = 19, 40.4%) comprised patients who underwent complete correction; Group II comprised patients who had undergone one or more palliative procedures. In Group II, there were 13 survivors at the end of the study (Group IIA); 14 patients died (Group IIB) and one was lost tot follow-up. The global mortality was 38% (21% in Group I and 52% in Group II). Overall management was intense: 166 cardiac catheter studies, 109 surgical operations including 48 systemico-pulmonary anastomoses, 34 right ventricular outflow reconstructions, I Ilbawi procedure. The survival was higher in Group I (79%) than in Group II (48%) indicating a clear advantage in reestablishing as normal as possible anatomic and haemodynamic status. Patients in Group I had a higher incidence of pulmonary artery confluence, patent ductus and an anatomically simple form of pulmonary atresia with VSD, all good surgical prognostic factors. The first palliative procedure was performed on average at 35 months in Group I, 46 months in Group IIA and 24 months in Group IIB; complete correction, when possible, was performed at about the 10th year, after an average of 3 operative procedures per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1993

Fine mapping of neutralization epitopes on duck hepatitis B virus (DHBV) pre-S protein using monoclonal antibodies and overlapping peptides.

To define the residues involved in duck hepatitis B virus (DHBV) neutralization at the amino acid level, we have used a procedure combining monoclonal antibodies (MAbs) and overlapping octapeptides (Pepscan). Two neutralizing MAbs (SD20 and 900), specific for the pre-S protein were shown to reduce DHBV infectivity in vivo by 75 and 90%, respectively, while complete protection of ducklings was achieved with a polyclonal antiserum raised against the bacterially expressed first 131 amino acids of the DHBV pre-S region (DHBpre-S). Using fusion polypeptides, the binding sites of these MAbs were localized between aa 77 and 100 on pre-S protein. We have used octapeptides spanning the pre-S sequence from aa 64 to 115 for fine mapping of these epitopes. Within the sequence scanned, the polyclonal anti-DHBpre-S antiserum recognized a region exclusively limited to the residues E82-K95, suggesting immunodominance of this region in the sequence aa 64-115. The epitope recognized by Mab 900 was mapped within the same region, whereas the epitope recognized by Mab SD20 was localized downstream from this region. To define the amino acids essential for binding to the highly neutralizing Mab 900, we have used single amino acid replacement and demonstrated that two residues Q87 and W88 were important for antibody recognition.

Amino Acid Sequence↗
PubMed1993

Duck hepatitis B virus (DHBV) as a model for understanding hepadnavirus neutralization.

The role of the immune response to the human hepatitis B virus (HBV) envelope proteins in neutralization of viral infectivity has been well documented. The similarity between HBV, prototype member of the hepadnavirus family, and the closely related duck hepatitis B virus (DHBV) has allowed, use of the latter as a convenient model for the study of molecular mechanisms of HBV replication and neutralization. In this brief review, we will examine the HBV and DHBV envelope proteins and their role as targets for virus neutralization.

Amino Acid Sequence↗
PubMed1993

Infection of a leukemic cell line (K562) by hepatitis B virus induces cell growth inhibition.

Hepatitis B virus inhibits the in vitro growth of the human leukemic cell line K562; however, the mechanism of this growth inhibition is not understood. One to 12 days after exposure, viral DNA and RNA were detected in K562 cells by Southern blot and reverse-transcriptase polymerase chain reaction analyses. Virus-containing serum that was heat-inactivated failed to inhibit cell growth and no viral DNA or RNA was detected in these cells. In addition, murine monoclonal antibodies directed to hepatitis B virus surface epitopes neutralized the virus-induced growth inhibition whereas antibodies to hepatitis B virus core epitopes failed to suppress the inhibition. These results indicate that in vitro infection of K562 cells by hepatitis B virus causes inhibition of hematopoietic cell line growth.

Antibodies, Monoclonal↗
PubMed1991

In vivo neutralization of duck hepatitis B virus by antibodies specific to the N-terminal portion of pre-S protein.

The neutralization of duck hepatitis B virus (DHBV) infection using antibodies directed against the N-terminal portion of the large surface protein was examined in vitro and in vivo. We demonstrate here that a monoclonal antibody, directed against an epitope mapped between aa 77 and aa 100 on the DHBV pre-S, exerts a similar neutralizing activity (77%) both in vivo and in vitro. Furthermore, we have found that a polyclonal antiserum raised against the bacterially expressed 131 first amino acids of the DHBV pre-S region abolished the infectivity of DHBV in ducklings. Therefore, antibodies against a peptide representing most of the DHBV pre-S region (1-131) or a monoclonal antibody specific to an epitope within this region neutralizes in vivo DHBV infectivity.

Animals↗
PubMed1991

Natural and experimental infection of wild mallard ducks with duck hepatitis B virus.

Wild duck populations were investigated over a 4 year period for duck hepatitis B virus (DHBV) infection and liver disease. It appeared that DHBV is endemic in wild migratory mallards from France and the U.S.A., although neither hepatocellular carcinoma nor viral DNA integration could be detected in liver samples examined. The follow up of natural infection indicated that wild mallards developed significantly higher serum titres to DHBV DNA than Pekin ducks. The results of experimental transmission demonstrated that such differences in viraemia were not related to the breed of ducks but to the virus isolate, since the wild mallard-isolated DHBV (DHBV WM) induced significantly higher viraemia in both mallard and Pekin ducklings compared to the domestic Pekin DHBV (DHBVP) isolate. The naturally infected mallard and Pekin ducks had only minor histological lesions of the liver compared with experimentally infected birds. There was no correlation between the intensity of viraemia and the severity of liver lesions, suggesting that as for mammalian hepadnaviruses the hepatic injury in DHBV-infected ducks is probably immunologically mediated.

Animals↗
PubMed1991

Vitiligo: care and treatment.

Vitiligo is a condition of hypopigmentation. An overview of the diseases and treatment options are discussed. A case study is presented in which encouraging results have been obtained using PUVA and fluocinonide. Nursing considerations are listed.

Adult↗