Biomedical subjects

Patrice Morel

Publications and source records attributed to Patrice Morel.

25 records · Page 2Linked to original sources

PubMed2002

Prognostic value of quantitative Kaposi sarcoma--associated herpesvirus load in posttransplantation Kaposi sarcoma.

Organ transplant recipients have a higher risk of Kaposi sarcoma (KS). A quantitative real-time polymerase chain reaction assay was developed to evaluate KS-associated herpesvirus (KSHV) as a prognostic tool in transplant recipients with KS. Forty-three patients who developed KS after transplantation were included in a cross-sectional study to correlate virus load with transplantation or KS parameters. Seventeen patients (40%) had KSHV viremia (>100 copies/microg of DNA; median, 6067 copies/microg of DNA). Factors associated with these levels of viremia by univariate analysis were progression of KS (P=.00002), time from KS diagnosis (P=.0007), actual stage of KS (P=.006), initial stage of KS (P=.22), graft loss (P=.013), and time from transplantation (P=.0246). Disease progression remained associated with KSHV viremia in a multivariate analysis (P=.01). Thus, quantification of KSHV load in peripheral blood mononuclear cells could represent a useful tool for monitoring transplant recipients with KS.

Cohort Studies↗

PubMed2002

HIV-1 infection of primary effusion lymphoma cell line triggers Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a gammaherpesvirus etiologically linked to primary effusion lymphoma (PEL), to a subset of multicentric Castleman's disease and to Kaposi's sarcoma (KS), the most common neoplasm associated with AIDS. Among KSHV-infected individuals, the risk of KS is much higher in those with human immunodeficiency-1 (HIV-1) infection than among those with other types of immunosuppression, suggesting a direct action of HIV-1 on KSHV replication. We show in our report that BC-3 cells, a chronically KSHV-infected B-cell line of a PEL origin, are permissive to HIV-1, offering a new tool for studying the interactions between these 2 viruses. In these cells, HIV-1 infection leads to reactivation of latent KSHV genomes, as demonstrated by the expression of KSHV lytic viral mRNAs. Although recombinant HIV-1 gp120 fails to enhance herpesvirus expression, transient transfection of the HIV-1 trans-activator Tat suffices to reactivate latent KSHV. By showing that HIV-1 infection directly reactivates latent KSHV, our results suggest a direct role of HIV-1 in the onset of KS in coinfected individuals.

Bacterial Proteins↗

PubMed2002

Human herpesvirus 8 seroprevalence in an STD clinic in Paris: a study of 512 patients.

BACKGROUND: Human herpesvirus 8 (HHV-8) is thought to be possibly sexually transmitted in some populations, but few data are available on this mode of transmission. GOAL The goal was to study HHV-8 seroprevalence in patients attending a sexually transmitted disease (STD) clinic and to search for predictive factors of HHV-8 seropositivity. STUDY DESIGN: Five hundred twelve consecutive patients attending the STD clinic of Hôpital Saint-Louis (Paris) were tested for HHV-8 antibodies (immunofluorescence assay using two cell lines, BCP-1 and ISI n. butyrate [3 mmol/l]). A standardized questionnaire was used to obtain demographic, behavioral, and clinical data. Predictive factors of HHV-8 seropositivity were considered in univariate and multivariate analysis with use of logistic regression models. RESULTS: In testing of the patients for HHV-8 antibodies, 67/512 (13.1%) tested positive: 53/346 (15.3%) of men and 14/166 (8.4%) of women ( = 0.03). The predictive factors of HHV-8 seropositivity for men were the country of origin (Central Africa, odds ratio [OR]: 7.5; North Africa, OR: 5.5), homosexuality (OR: 3.7), and visiting prostitutes (OR: 7.1). For women they were country of origin (Central Africa, OR: 8.3) and presence of HSV-2 antibodies (OR: 6.5, tendency). CONCLUSION: Our study does not show clear relationships between HHV-8 seropositivity and sexual behavior, apart from homosexuality, but visiting prostitutes (for men) and HSV-2 seropositivity (for women) could be subtle clues supporting the hypothesis of heterosexual transmission.

Antibodies, Viral↗

PubMed2002

[Arrector pili myositis in a patient with dermatomyositis: an unusual histological feature].

Dermatomyositis is a rare inflammatory disease with a difficult diagnosis on cutaneous biopsies, since alterations are often little marked and non specific. A 52-year-old patient had severe paraneoplastic dermatomyositis. He had an erythematous rash on the trunk, and erythematous papules on the back of the hands. The first histological cutaneous lesion was a striking arrector pili myositis. Arrector pili myositis has rarely been described, and is thought to be linked with Wong type eruption occurring in dermatomyositis. Arrector pili myositis might constitute an helpful sign in the diagnosis of dermatomyositis, but its specificity and sensitivity are unknown. We compared this case to four previously reported cases. In these five cases, arrector pili myositis was not associated with a particular sub-type of dermatomyositis or with poor prognosis.

Biopsy↗

PubMed2000

Six putative two-component regulatory systems isolated from Lactococcus lactis subsp. cremoris MG1363.

The genetic elements specifying six putative two-component regulatory systems (2CSs) were identified on the chromosome of Lactococcus lactis MG1363. These 2CSs appear to represent distinct loci, each containing a histidine kinase and response-regulator-encoding gene pair. Transcriptional analysis of the six 2CSs was performed either by generating transcriptional fusions to a reporter gene or by primer extension. Two of the systems appeared to be expressed constitutively at a high level, whilst the remaining four exhibited growth-phase-dependent expression. Insertional mutagenesis established that the two constitutively expressed 2CSs are necessary for normal cell growth and/or survival. Mutational analysis of the remaining four systems revealed that they are implicated in susceptibility to extreme pH, osmotic or oxidative conditions, or the regulation of phosphatase activity in L. lactis.

Amino Acid Sequence↗

PubMed1998

Two-component signal-transducing systems involved in stress responses and vancomycin susceptibility in Lactobacillus sakei.

Fragments of five rrp genes encoding response regulators (RRs) in Lactobacillus sakei were amplified by PCR using degenerate oligonucleotide primers. The five rrp genes were part of distinct loci that also comprised hpk genes encoding histidine protein kinases (HPKs). The putative RRs belonged to the OmpR-PhoB subclass of response regulators that consist of N-terminal receiver and C-terminal DNA-binding domains. The putative HPKs were members of the EnvZ-NarX family of orthodox histidine protein kinases which possess two transmembrane segments in a non-conserved N-terminal domain and a C-terminal cytoplasmic kinase domain. Insertional inactivation of the rrp genes indicated that the RRs are implicated in susceptibility to the glycopeptide antibiotic vancomycin, and to extreme pH, temperature and oxidative conditions.

Amino Acid Sequence↗

PubMed1997

Identification by PCR of genes encoding multiple response regulators.

Environmental sensing in bacteria often involves the concerted action of sensor kinases and response regulators. Degenerate oligonucleotide primers were designed on the basis of amino acid similarity in the response regulators of these two-component systems. The primers were used in PCR to specifically amplify an internal DNA segment corresponding to the receiver module domain from genes encoding response regulators. Amplification products of the expected size were obtained from 12 different Gram-positive and Gram-negative bacteria. Sequence analysis revealed that 22 DNA fragments, which clearly originated from response regulator genes, were amplified from Escherichia coli, Agrobacterium tumefaciens, Bacillus subtilis and Lactobacillus bulgaricus. In each of these four species the receiver module of putative response regulator genes, which do not seem to be related to any of the already characterized genes, was identified. This simple and powerful method is therefore particularly useful for discovering new signal transduction systems which cannot be revealed by usual genetic studies.

Agrobacterium tumefaciens↗