Biomedical subjects
Publications and source records attributed to C Gay.
Microarray expression analysis has become one of the most widely used functional genomics tools. Efficient application of this technique requires the development of robust and reproducible protocols. We have optimized all aspects of the process, including PCR amplification of target cDNA clones, microarray printing, probe labeling and hybridization, and have developed strategies for data normalization and analysis.
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.
Formation of a colored complex between ferric iron and xylenol orange has been used in a variety of applications, but there is disagreement about the number of complexes that exist, their stoichiometry, pH dependence, solvent effects, and other parameters. In this study we investigated the use of the complex to measure micromolar concentrations of iron in aqueous and alcohol solutions. The results show that the optimum wavelength for the measurement is 560 nm, that only a 1:1 ferric:xylenol orange complex forms, and that its molar absorption coefficient is affected by the solvent, the source of the xylenol orange, and the pH. Under the recommended conditions, formation of the complex is completed in less than 5 min and it is stable in several solvents. Its molar absorption coefficient in 25 mM H(2)SO(4) is 20,100 or 14,500 M(-1) cm(-1), depending on the source of the dye. A recommended protocol for the use of the assay is given.
A range of hydroperoxides were reduced by ferrous ions in acid solutions and the amount of ferric product was measured as a xylenol orange complex at 560 nm. Dilute sulfuric acid, 50% acetic acid, and acidified 90% methanol proved to be suitable solvents. The color developed within 15 min and was stable for several hours in most solvents. The apparent molar absorption coefficients (epsilon(app)) of H(2)O(2) and of the t-butyl, cumene, bovine serum albumin, and linoleate hydroperoxides were measured, using known hydroperoxide concentrations determined independently by an iodometric assay. The epsilon(app) values differed significantly and depended on the hydroperoxide, the solvent, and the source of the xylenol orange. The numbers of Fe(3+) ions formed by a range of hydroperoxides in different solvents showed that H(2)O(2) gave 2.5, t-butyl and cumene hydroperoxides 5, and the other hydroperoxides 2 Fe(3+) ions per -OOH group. This general finding allows the determination of approximate hydroperoxide concentrations even in chemically complex systems. Accurate measurements require knowledge of the nature of the hydroperoxide and its epsilon(app) and careful control of the assay conditions. However, the convenience of the assay makes it potentially useful in a variety of applications.
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.
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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.
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OBJECTIVE: Accurate diagnosis of pyelonephritis using clinical and laboratory parameters is often difficult, especially in children. The main aims of this prospective study were to compare the value of different imaging techniques [renal sonography, cortical scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc DMSA) and computed tomography (CT)] in detecting renal involvement in acute urinary tract infections and to determine the sensitivity of DMSA scans for permanent renal scars 6 months later. MATERIALS AND METHODS: Between February 1992 and January 1993, 55 children admitted to our pediatric unit with febrile symptomatic urinary tract infections were eligible for analysis. Ultrasonography (US), DMSA scanning and micturating cystourethrography were performed in every case. Only 18 children underwent CT. A second DMSA scan was performed in 48 children a mean of 7.5 months after the first. RESULTS: US abnormalities were found in 25 children (45 %). The first DMSA scan showed a parenchymal aspect suggestive of pyelonephritis in 51 patients (93 %). Among the 18 patients studied by CT, 14 had abnormalities. Normal US findings did not rule out renal parenchymal involvement. Scintigraphy appeared to be more sensitive than CT for renal involvement. The frequency and degree of initial renal parenchymal damage seemed to correlate with vesicoureteral reflux, but the most severe initial parenchymal defects were not associated with marked clinical or laboratory manifestations. Repeat DMSA scans, performed on 45 kidneys with abnormalities at the first examination, showed resolution in 19, improvement in 16, persistence in 8 and deterioration in 2. The prevalence of vesicoureteral reflux was not higher in patients with renal scarring on the second DMSA scan than in patients whose scans showed an improvement. CONCLUSION: DMSA scans should be considered as a reference in the detection and follow-up of renal scarring associated with acute urinary tract infection as this technique is more sensitive than US and CT, the latter being unsuitable because it entails radiation exposure and sedation of patients.
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Acute lymphoblastic leukemia (ALL) in the elderly is characterized by its poor prognosis. Forty patients with ALL, aged 55 years or older, and with good performance status (ECOG <3) were prospectively treated according to an age-adapted regimen: induction therapy was derived from the LALA87 protocol while the feasibility of treatment with interferon combined with chemotherapy was assessed during maintenance. Compared with younger adults treated according to the LALA87 protocol, elderly patients did not present with more adverse prognostic features, except for a lower incidence of T cell ALL (9 vs 31%, P=0.005). There were even less patients with a high leukocyte count (15 vs 38%, P=0.003), a characteristic associated with adverse prognosis while the incidence of Philadelphia-positive (Ph-positive) ALL was not significantly increased compared to younger adults (31 vs 20%, P=0.2). After completion of induction therapy, with or without salvage treatment, 85% (CI: 70-94%) obtained a complete response (CR) while treatment-related mortality during induction was 7.5% (CI: 2-20%). Median overall survival and disease-free survival were 14.3 months and 14 months, respectively, which, although inferior to results achieved in younger adults, compares favorably with available data in the elderly. Treatment with IFN proved feasible in most patients but had to be discontinued in eight patients because of toxicity. Age-adapted treatment improves the prognosis of ALL in the elderly even if, in most cases, a cure cannot be achieved.
Providing information to the patients and their families represents one of today's new conditions in the management of the depressed. It will help their adaptation to the illness and its effects. It will maintain a good therapeutic alliance among patients and practitioners, and will enhance their treatment adherence thus improving their quality of life. Several aspects are essential in the transmission of this information: it must be available to every patient, easily accessible, concise, repeated and revised as necessary, discouraging self-diagnosis and self-prescription. This education must be given personally by the physicians and the pharmacists. Depressed patients may also have an access to complementary sources: books, magazines and more rarely scientific journals. Patients' associations provide another potential source of information, offering a comprehensive approach to the patient and the illness. France-Déxpression is a depressive and manic-depressive patients association. Its goals are to provide information and support to the patients and their families, promoting a better understanding and recognition of depressive and manic-depressive illness.
BACKGROUND: The goal of this study was to estimate direct costs induced by the first year of treatment of cervix cancers according to the stage at diagnosis. METHODS: Fifteen patients of the Gynaecology Department of the Besançon hospital (Doubs, France) were involved in a prospective study to estimate the real cost of treatment of carcinomas in situ (CIS) by conization and of microinvasive carcinomas (MIC) by simple hysterectomy. Costs of invasive cancers were obtained from a retrospective analysis of 24 hospital records in the Radiotherapy Department. RESULTS: The average real cost of treatment for the CIS was 5023 FF (1995 French Francs). Real treatment cost of the MIC was 15,867 FF. The average cost of treatment for the IB and IIA cancers stage (FIGO classification) was 61,540 FF and 145,314 FF for the IIB to IV stage cancers. CONCLUSIONS: Cost-estimation of cervix cancer treatment according to the stage of diagnosis has to be done before starting a cost-effectiveness analysis of mass screening for cervix cancers. This study will allow us to take into account changes in the stages distribution following on a screening campaign.
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PURPOSE: A pharmacokinetic study was performed during a phase II clinical trial of irinotecan (CPT-11) to confirm the pharmacokinetic profile of this drug and its metabolite and to investigate interpatient and intrapatient pharmacokinetic variations and pharmacokinetic-pharmacodynamic relationships. PATIENTS AND METHODS: Twenty-six men and 21 women (mean age, 61 years) with metastatic colorectal cancer, performance status less than 3 (World Health Organization [WHO] scale), and normal renal and hepatic function were administered CPT-11 (350 mg/m2) by 30-minute intravenous (IV) infusion every 21 days. CPT-11 and its metabolites SN-38 and SN-38 glucuronide (SN-38G) were determined by high-performance liquid chromatography (HPLC) using fluorimetric detection. RESULTS: The mean CPT-11 clearance and area under the concentration-time curve (AUC) were 15.2 L/h. m2 and 24,769ng. h/mL, respectively. The large difference in SN-38 and SN-38G AUCs (559 v 2,283 ng. h/mL) was suggestive of extensive glucuronidation of SN-38. Interindividual variation in the metabolic ratio ([AUCSN-38 + AUCSN-38Gl/AUCCPT-11) was marked (coefficient of variation [CV] = 51.6%] compared with intrapatient variation in this variable (CV = 32.6%). A significant relationship existed between percentage reduction in neutrophil count and the AUC of CPT-11 (r = .597, P < .001) and SN-38 (r = .559, P < .001). No relationship was identified between any pharmacokinetic parameter and delayed diarrhea or therapeutic outcome. CONCLUSION: Interindividual variations in the metabolic ratio suggest interpatient variation in carboxylesterase activity. Furthermore, glucuronidation of SN-38 may also be in part responsible for the large interpatient variability in the total SN-38 AUC. Conversely, low intrapatient variation of this parameter was observed in this study, which indicates a lack of autoinduction of the carboxylesterase system. The relationship between neutropenia and both CPT-11 and SN-38 pharmacokinetic parameters confirms the results of previous studies.