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C Mougin

Publications and source records attributed to C Mougin.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Epidemiology of cervical papillomavirus infections. Recent knowledge].

GENERAL DATA: There is now considerable evidence that high risk human papillomaviruses (HPV), such as HPV 16, are closely associated with cancer of the cervix. HPVs that are primarily transmitted through sexual contact, are found in over 99% of the cases of invasive cervical cancer. Although most women can be infected during their sexual life, a small minority is at risk for developing cancer. The long latency period between primary infection and cancer emergence suggests that additional factors are involved in the process of tumor development: sexual behavior, immune status, genetic predispositions, nutritional status, tobacco use, socio-economical level. NATURAL HISTORY: HPVs infect epithelial cells of the transformation zone of the cervix. As with other sexually transmitted diseases, the incidence of HPV infection is highest among young women. However, this viral infection is more often than not transient, because most individuals develop an effective type-specific immune response. Approximately 1% of the population has genital warts and 4% of women have cervical precancerous lesions: low grade squamous intraepithelial lesion (LGSIL) or high grade SIL. These last lesions preferentially observed in women aged 35-40 yrs are at high risk of progression towards an invasive cancer. ONCOGENIC POTENTIAL OF HPV: Pre-malignant and malignant cells arise as a result of HPV DNA integration in the host cellular genome, and overexpression of the viral E6 and E7 oncogenes. Cells acquire a proliferative advantage by escaping growth control exerted by p53 and p 105Rb. Both cellular proteins are indeed inactivated respectively by E6 and E7 proteins. Aneuploidy and karyotypic abnormalities are also key events in the tumor progression. A PREVENTABLE DISEASE: Cervical cancer is more than ever a preventable disease. While waiting for clinically applicable vaccination programs, strategies to prevent cervical cancer include 1) improved screening covering the widest possible population and using HPV testing, 2) close management and follow-up of women with precancerous lesions.

Adult↗
PubMed2001

[Melanoma: role of ultraviolet radiation: from physiology to pathology].

EPIDEMIOLOGIC DATA: The frequency of malignant melanoma, by far the most fatal skin cancer, has increased by a factor of approximately 15 in the past 60 years. The factors underlying this rapid increase are incompletely understood, although ultraviolet radiations are likely strongly implicated. Epidemiologic studies demonstrate the role of altered patterns of sun exposure, and overexposition to UVA radiation, as confirmed by experimental data on animal models. BIOLOGICAL ASPECTS: Melanin produced by melanocytes has a photoprotective function in the skin, whereas UVB-induced DNA damage enhance the repair capacity of these cells. However, this photoprotective effect is not induced by intense intermittent sun exposure. In addition, melanocytes demonstrate resistance to UVB-induced apoptosis and are thus at high risk for incorporating UV-induced mutations. MOLECULAR ASPECTS: Different mutations in susceptibility genes (CDKN2A, INK4), or in genes implicated in control of cell cycle or maintenance of cell integrity (DNA repair) are involved in initiation and promotion steps of melanocarcinogenesis. Moreover, tumor progression is stimulated by UVB through the activation of different target genes that are implicated in control of melanoma environment (immune surveillance, angiogenesis, growth factors...).

Adolescent↗
PubMed2001

Staurosporine-induced apoptosis of HPV positive and negative human cervical cancer cells from different points in the cell cycle.

In the present study, we compare the sensitivity of CaSki and HeLa cells (HPV positive, wild-type p53) and C33A cells (HPV negative, mutated p53) to a protein kinase inhibitor, the staurosporine (ST). We show that ST can reversibly arrest the three cervical-derived cell lines, either in G1 or in G2/M. Beyond certain ST concentrations or/and over 24 h exposure, the cells underwent apoptosis. This process took place in G1 and G2/M for C33A and CaSki plus HeLa cell lines, respectively. By using an in vitro cell-free system, we demonstrated that cytoplasmic extracts from apoptotic cells were sufficient to induce hallmarks of programmed cell death on isolated nuclei. Moreover, we found that only G2/M cytoplasmic extracts from viable CaSki and HeLa cells supplemented with ST, triggered apoptosis while exclusively G1 cytoplasmic fractions from C33A cells were efficient. Our study describes a possible involvement of the HPV infection or/and p53 status in this different ST-induced apoptosis susceptibility.

Apoptosis↗
PubMed2000

Acyclovir-resistant bilateral keratitis associated with mutations in the HSV-1 thymidine kinase gene.

PURPOSE: To evaluate the contribution of molecular methods for the diagnosis of an acyclovir-resistant HSV-1 bilateral keratitis in an AIDS patient and to report a new point mutation in the nucleotide sequence of the thymidine kinase (tk) gene involved. METHODS: A 31 year old HIV-positive female presented with severe, active, bilateral and sight-threatening keratitis of 6 months duration, which was treated unsuccessfully with acyclovir. After corneal biopsy, samples were analysed by standard virological procedures, in situ hybridization, and PCR. The tk gene was cloned and subsequently sequenced. RESULTS: Conventional virological methods remained inconclusive. However, in situ hybridization and PCR rapidly confirmed the diagnosis of HSV-1 keratitis. The tk gene sequence revealed the presence of five variations previously described in two reference strains, but also a new point mutation at nucleotide position 431 which leads to an amino-acid change at position 144 that supported the hypothesis of a putatively altered functional form of the enzyme. Intravenous foscarnet treatment in an induction regimen was effective and cicatrization occurred within 3 weeks. CONCLUSIONS: PCR and in situ hybridization are effective and powerful techniques when other virological procedures are non-contributive, particularly in immunocompromised patients previously treated with antiviral drugs. The new point mutation identified in the tk gene may be associated with resistance to acyclovir.

AIDS-Related Opportunistic Infections↗
PubMed2000

Cleavage of the diketonitrile derivative of the herbicide isoxaflutole by extracellular fungal oxidases.

Isoxaflutole is a herbicide activated in soils and plants to its diketonitrile derivative, the active herbicide principle. The diketonitrile derivative undergoes cleavage to the inactive benzoic acid analogue. In this paper, it is established that an oxidative mechanism implicating two successive reactions in the presence of dimethyldioxirane can chemically initiate the cleavage of the diketonitrile. It is also shown that two white rot strains, Phanerochaete chrysosporium and Trametes versicolor, are able to convert the diketonitrile to the acid when cultured in liquid media. This main metabolite amounts to 24.6 and 15.1% of initial herbicide content after 12-15 days of culture. Another polar metabolite represents <3.7% of the parent compound amount during the same period. Oxidative enzymes produced by the fungi show a time course similar to that of diketonitrile degradation. Purified laccase (EC 1. 10.3.2), in the presence of 2 mM 2, 2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) acting as a redox mediator at pH 3 supports the reaction with rates of 0.3-0.4 nmol h(-)(1) unit(-)(1).

Extracellular Space↗
PubMed2000

[Human papillomaviruses, cell cycle and cervical cancer].

Human papillomaviruses (HPVs) are associated with a broad spectrum of cutaneous and mucosal lesions. Until now, more than 120 genotypes have been identified. Most HPVs are associated with benign lesions. Nevertheless certain HPV types are frequently found in carcinomas. For instance, HPV 16 and 18 which are frequently associated with cervical cancer, are capable of immortalizing and transforming primary keratinocytes. The mechanism of transformation is linked to the viral genome integration into the cell's DNA, accompanied by an overexpression of the E6 and E7 genes. The viral gene products interact with cellular proteins that regulate the cycle progression. In particular, the E6 protein binds to the p53 and the E7 protein binds to the p105(Rb). The inactivation of both cellular proteins distorts the cell cycle and results in genetic instability and cellular gene alterations. This article reviews the role of the viruses in the carcinogenesis, the genome structure and the gene expression of HPVs. It also addresses the cell cycle regulation with a focus on the role of HPVs in cell transformation.

Cell Cycle↗
PubMed1999

[Human Herpesvirus 6: general information and infections in organ transplantations and hematopoietic stem cell grafts].

GENERAL DATA: Human herpesvirus 6 (HHV-6) infects 90% of the human population before the age of 4 years, recognized as a childhood disease (sixth disease) or with no clinical manifestation. HHV-6 DNA has partial homogly with cytomegalovirus DNA. Two variants, A and B, are known. The main target cells are CD4+ T cells and macrophages via a partially elucidated mechanism. Primary infection is followed by a latency period and episodes of reactivation. Truly protective targets of the immune response are unknown. POORLY UNDERSTOOD NATURAL HISTORY: In organ transplant or hematopoietic stem cell recipients, the natural history of HHV-6 infection is difficult to establish because of small sample size in certain series, the lack of controls both for patients and samples and differences in the sensitivity of diagnostic tests. Serology is non-specific and cannot be used to study reinfection. Different studies have relied on culture and isolation, detection of viral antigens with monoclonal antibodies and PCR using mononucleated cells, serum and plasma. PATHOGENICITY: In heart transplant recipients, HHV-6 infection can cause hepatitis and pancreatic or upper digestive tract disorders. It has also been suggested that HHV-6 could cause complications in liver transplant recipients and be involved in rejection episodes after kidney transplantation. In bone marrow graft recipients, HHV-6 could cause early onset interstitial pneumopathy, myelosuppression phenomena and aggravated graft versus host reactions. Nevertheless, viral DNA has been found in certain healthy controls. OTHER POSSIBILITIES: HHV-6 could also be a co-factor worsening cytomegalovirus infections as has been suggested in liver, heart and bone marrow recipients. A few cases of HHV-6 encephalitis have been reported in the literature and would appear to be authentic in transplanted or grafted subjects. Ganciclovir is effective. However, the practical clinical impact of HHV-6 infection remains to be established.

Hematopoietic Stem Cell Transplantation↗
PubMed1999

[Does a particular risk associated with papillomavirus infections exist in women with lupus?].

PURPOSE: There is strong evidence that papillomavirus infections (HPV), especially infections with HPV 16/18, are involved in the development of dysplasia and cancers. Cervical cancer is thought to be increased in women with systemic lupus erythematosus (SLE). METHODS: To assess this risk we studied cervical smears from 11 women with SLE and determined the prevalence of HPV infection by in situ hybridization. RESULTS: Dysplasia was found in 9% of women with SLE and in 0.03% of control subjects (non significant difference). Dysplasia was found to be six times more frequent in women with SLE (18% versus 3%, P < 0.01). HPV prevalence in normal smears was 37.5% in women with SLE versus 14.7% in control subjects (non-significant difference). Identified HPV genotypes were those for which intermediate or high risk is well established. No correlation was found between infection or dysplasia risk and the lymphocyte count or a previous treatment with cyclophosphamide. CONCLUSION: We conclude that women with SLE would be at increased risk of HPV infection, dysplasia and cervical cancer. We suggest that women with SLE should be regularly tested for cervical cancer by colposcopy, especially in case of HPV 16 infection.

Adult↗
PubMed1999

Direct in situ reverse transcriptase-linked polymerase chain reaction with biotinylated primers for the detection of hepatitis C virus RNA in liver biopsies.

To assess the presence and the cellular distribution of hepatitis C virus (HCV) RNA in the liver of 11 patients with confirmed HCV infection, a direct in situ reverse transcriptase-linked polymerase chain reaction (RT-PCR) method was performed on formalin-fixed and paraffin-embedded biopsies. The oligonucleotide primers used were specific to the 5' non coding region. An unlabelled downstream oligonucleotide served as a primer for reverse transcription as well as PCR. The upstream oligonucleotide serving as a primer for PCR was biotinylated, allowing a direct enzymatic detection of PCR products. HCV infected cells revealed cytoplasmic staining mainly concentrated towards the interface of the nucleus and cytoplasm. Most of the stained cells were hepatocytes and sometimes Kupffer cells. The results were compared with those obtained by RT-PCR of RNA extracted from the corresponding tissue block. Extracted HCV RNA could be detected in liver tissues of nine out of 11 (82%) infected patients. The detection rate using in situ RT-PCR was 7/11 (63%). The use of labelled primers improved specificity of direct in situ methods, by preventing non-specific incorporation of labelled dNTPs into fragmented DNA. Further studies are however required in order to increase detection sensitivity of HCV infection by in situ molecular methods.

Biotin↗
PubMed1999

Genital human papillomavirus infection among women recruited for routine cervical cancer screening or for colposcopy determined by Hybrid Capture II and polymerase chain reaction.

The purpose of this study was to evaluate the clinical use of the Hybrid Capture (HC)-II system for the detection of human papillomavirus (HPV) DNA to identify women at risk of progression to high grade squamous intraepithelial lesions (HGSIL) and carcinomas by differentiating low risk (LR) HPV types (6, 11, 42, 43, 44) and high/intermediate risk (HR) HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68). Five hundred and ninety-six women were enrolled in the study. Among them, 466 attended the hospital for routine cytologic screening and 130 were referred for colposcopy because of an abnormal Pap smear. The presence of HPV DNA was tested in cervical samples collected with the Digene Cervical Sampler in Digene Specimen Transport Medium (Digene Corporation, Silver Spring, MD, U.S.A.) using the HC-II assay. Results were compared with those obtained by polymerase chain reaction (PCR) using the MY09-MY11 primers followed by several hybridizations with specific probes. The overall HPV positivity was 32.9% by HC-II and 37.8% by PCR. Among cytologically normal smears, 19.5% were positive by HC-II (14.3% HR) and 25.1% by PCR. Of the atypical squamous cells of undetermined significance samples, 52.9% were positive by HC-II (41.1% HR) and 55.9% by PCR. Of the low grade SIL, 64.5% were positive by HC-II (59.4% HR) and 68.7% by PCR. The HPV positivity rate was found identical by both techniques in high grade smears (81.6%) and squamous cervical carcinomas (100%). By using PCR as the reference method, the sensitivity of HC-II was higher among women with abnormal cytology than with normal cytology (87.3% vs. 70%). Specificity was 80.8% and 97.5%, respectively. In summary, these results indicate that the HC-II method and MY-PCR identified nearly equivalent prevalences of HPV in cervical smear specimens.

Adolescent↗
PubMed1999

[Papillomavirus-induced anogenital lesions in 121 HIV seropositive men. Clinical, histological, viral study, and evolution].

OBJECTIVE: To determine the prevalence of the Human Papillomavirus (HPV) in Human Immunodeficiency Virus (HIV) infected men, using clinical examination and molecular hybridization in situ. PATIENTS AND METHODS: From May 1995 to May 1997 we studied the prevalence, clinical and histological characteristics, the types and the evolution of the HPV lesions among 121 HIV-infected men. The HPV DNA was determined by molecular hybridization in situ, using biotinylated probes which recognized HPV types 6/11, 16/18 and 31/33/35 in 79 p. 100 (5/19) of the patients (17 biopsies). RESULTS: Sixteen per cent (19/121) of the patients are HPV infected: genital warts in 37 p. 100 (7/19), anal warts in 37 p. 100 (7/19), and ano-genital warts in 26 p. 100 (5/19) of the patients. In every case of anal codyloma, intracanalar lesions were found. In 47 p. 100 (9/19) of the cases, histological exam showed an intra-epithelial neoplasia. The HPV types 6/11, 16/18 and 31/33/51 were positive in 53 p. 100 (9/17), 35 p. 100 (6/17) and 35 p. 100 (6/17) biopsies respectively. High-risk types of HPV have been noted in 71 p. 100 (12/17) of the biopsies. The evolution of the clinical lesions was: recovering in 47 p. 100 (9/19) of the patients (after 3 months of treatment), recurrence in 16 p. 100 (3/19) of the anal warts (after 1 to 3 months of treatment), stabilization in 16 p. 100 (3/19) of the genital warts (after 6 months of treatment) and extension in 11 p. 100 (2/19) of the anogenital warts (after 3 months of treatment). CONCLUSION: The high prevalence of condyloma and dysplasia emphasizes the importance of the anogenital exam in HIV-positive patients. In case of anal lesions, anuscopy and biopsy are required. We insist on the need to closely follow these patients with HPV lesions in order to adapt treatment. Anal cytology and HPV-DNA detection by Hybrid Capture Assay, should be developed for screening and prevention of the malignant transformation of HPV lesions in this population.

AIDS-Related Opportunistic Infections↗
PubMed1999

Human papillomavirus detection by non isotopic in situ hybridization, in situ hybridization with signal amplification and in situ polymerase chain reaction.

Classical in situ hybridization (ISH) with biotinylated probes makes it possible to detect and localize human papillomavirus (HPV) nucleic acid sequences in cytological and histological materials. This method is however of limited value in the detection of a few copies of the virus. Moreover the specificity of such a technique is not always convincing when ISH signals are small and/or of low intensity. Recently, much attention has been focused on the utility of the in vitro polymerase chain reaction (PCR) and especially on PCR-single strand conformation polymorphism (SSCP) to amplify small amounts of viral DNA with accurate hybrid specificity. But the latter method requires nucleic acid extraction and tissue destruction. Thus, correlation between the PCR results and histological findings is not possible. Hence, the aim of our current study was to apply to HeLa cells and cervical formalin-fixed and paraffin-embedded biopsies, a novel procedure of ISH signal amplification, the catalyzed signal amplification (CSA). Such a procedure is based on the deposition of streptavidin-horseradish peroxidase catalyzing the deposition of biotinylated tyramide molecules on the location of the probed target. The biotin accumulation is then detected with streptavidin peroxidase and diaminobenzidine. The results were compared with those obtained by direct and indirect in situ PCR. The catalysed signal amplification successfully increased the sensitivity and efficiency of ISH for the detection of rare sequences in HPV infected cells and histological materials. Such a method was found simpler and faster than in situ PCR and tissue morphology was better preserved.

Biotin↗
PubMed1998

The L1 major capsid protein of human papillomavirus type 16 variants affects yield of virus-like particles produced in an insect cell expression system.

The L1 major capsid proteins of six human papillomavirus type 16 (HPV-16) strains were expressed in insect cells by using recombinant baculoviruses. Virus-like particles (VLPs) which appeared similar to empty virions were identified by electron microscopy for all HPV strains investigated. However, the yield of VLPs produced varied in a range from 1 to 79 depending on the HPV-16 strain. The L1 proteins of these strains differed by up to 15 amino acids from the L1 protein of the prototype HPV-16 strain. Mutations in the amino acid region from residues 83 to 97 seemed to affect the level of expression of the L1 protein. These results are important when considering the development of HPV vaccines and serological tests. They indicate that strains inducing high levels of VLP production must be selected for the development of vaccines. Moreover, the L1 proteins of all strains investigated were able to bind with DNA. We also investigated the seroreactivities of VLPs derived from three different HPV-16 strains from Algeria, Senegal, and the Philippines by testing sera from women from 11 countries in immunoglobulin G-specific enzyme-linked immunosorbent assays. We observed a strong correlation between the reactivities of the three different VLP variants, independent of the geographical origin of the sera investigated. These results indicate that the three strains investigated are serologically cross-reactive despite the fact that their L1 proteins differ in 14 amino acids and suggest that VLPs derived from only one HPV-16 strain could be sufficient for the development of an HPV-16 vaccine and anti-HPV-16 tests.

Amino Acid Sequence↗
PubMed1997

Solid phase cytometry allows rapid in situ quantification of human papilloma virus infection in biopsy material.

Solid phase cytometry would be an asset for many histological and cytological studies. Current microscope-based cytometers and image analysis systems are too slow to analyze specimens several millimeters wide. We have recently shown that a rapid wide area laser scanning device that operates on solid supports has a linear response. We assess it here for solid phase cytometry. Each cell detected by the cytometer can be automatically positioned for visual observation in the field of an epifluorescence microscope (conventional or confocal) in which the stage is driven by the instrument's computer. We were able to detect and map human papillomavirus-infected cells labeled by fluorescent in situ hybridization in cervical condyloma biopsies. We could quantify the fluorescence emitted by these cells and show differences of up to 35-fold in fluorescence intensity between individual cells. These differences in intensity might reflect differences in viral copy number. The potential of the system to provide fast, reliable and reproducible analyses of solid tissue samples is discussed.

Biopsy↗
PubMed1997

[Obliterative arteriopathy in chronic rejection after hepatic transplantation. Search of cytomegalovirus genome by in situ hybridization and viral antigens by immunohistochemistry].

OBJECTIVES: This study was performed to assess the role of cytomegalovirus in the parietal infection of intrahepatic arteries in the pathogenesis of obliterative arteriopathy from chronic rejection after orthotopic liver transplantation. METHODS: We studied two groups of liver transplants by in situ hybridization and immunohistochemistry: group 1, including 10 liver grafts with obliterating arteriopathy, and group 2 including 7 liver grafts without any arterial disorders. The results were correlated with clinical data (cytomegalovirus infection and acute rejection). RESULTS: By in situ hybridization, cytomegalovirus DNA was identified in the media in 70% of transplants in group 1 and 42% in group 2. Detection of immediate early and late antigens by immunohistochemistry was negative. Cytomegalovirus infections were often associated with acute rejection. CONCLUSION: These results suggest that cytomegalovirus detected in arteries is latent, and that cytomegalovirus probably does not play a role in the pathogenesis of chronic rejection obliterative arteriopathy.

Adult↗