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Biomedical subjects

P Chevallier

Publications and source records attributed to P Chevallier.

At least 19 recordsLinked to original sources
PubMed2006

Pelvic prolapse: static and dynamic MRI.

Pelvic magnetic resonance is a simple and non-invasive imaging technique for dynamic and static assessment of the pelvic floor. The morphology of the support system is assessed by T2-weighted images. Dynamic sequences are used to assess pelvic prolapse. In this study we illustrate the normal and pathologic features of the levator ani muscle which represents the main active support of pelvic organs. Furthermore we describe the different types of prolapses, floor by floor, and the different staging techniques.

Female↗
PubMed2006

Choledocholithiasis: repetitive thick-slab single-shot projection magnetic resonance cholangiopancreaticography versus endoscopic ultrasonography.

This prospective study compares repetitive thick-slab single-shot projection magnetic resonance cholangiopancreatography (MRCP) with endoscopic ultrasonography (EUS) for the detection of choledocholithiasis. Fifty-seven consecutive patients (36 women, mean age 61) referred for suspected choledocholithiasis underwent MRCP, followed by EUS. Each procedure was performed by different operators blinded to the results of the other investigation. MR technique included a turbo spin-echo T2-weighted axial sequence with selective fat saturation (SPIR/TSE, TE=70 ms, TR=1,600 ms), followed by coronal dynamic MRCP. The same thick-slab slice was sequentially acquired 12 times as breath-hold single-shot projection imaging (SSh, TE=900 ms, TE=8,000 ms) centred on the common bile duct (CBD). Two experienced radiologists independently and blindly evaluated MR images for the detection of CBD stones. Their inter-observer agreement kappa was determined. Secondly, the two observers read MR images in consensus again. CBD stones were demonstrated in 18 out of 57 patients (31.6 %) and confirmed by endoscopic retrograde cholangiography (ERCP, n=17) or intraoperative cholangiography (n=1). Clinical follow-up served as the "gold standard" in patients with negative results without following invasive procedure (n=28). Sensitivity, specificity, accuracy, positive and negative predictive value for MRCP resulting from consensus reading were 94.9%, 94.4%, 94.7%, 97.4% and 89.5%, respectively. Corresponding values of EUS were 97.4%, 94.4%, 96.5%, 97.4% and 94.4%. Inter-observer agreement kappa was 0.81. Repetitive thick-slab single-shot projection MRCP is an accurate non-invasive imaging modality for suspected choledocholithiasis and should be increasingly used to select those patients who require a subsequent therapeutic procedure, namely ERCP.

Adult↗
PubMed2006

Transjugular liver biopsy: prospective evaluation of the angle formed between the hepatic veins and the vena cava main axis and modification of a semi-automated biopsy device in cases of an unfavorable angle.

In cases of transjugular liver biopsies, the venous angle formed between the chosen hepatic vein and the vena cava main axis in a frontal plane can be large, leading to technical difficulties. In a prospective study including 139 consecutive patients who underwent transjugular liver biopsy using the Quick-Core biopsy set, the mean venous angle was equal to 49.6 degrees. For 21.1% of the patients, two attempts at hepatic venous catheterization failed because the venous angle was too large, with a mean of 69.7 degrees. In all of these patients, manual reshaping of the distal curvature of the stiffening metallic cannula, by forming a new mean angle equal to 48 degrees , allowed successful completion of the procedure in less than 10 min.

Adult↗
PubMed2006

Plasma ribavirin concentrations during treatment of recurrent hepatitis C with peginterferon alpha-2b and ribavirin combination after liver transplantation.

After liver transplantation (LT) for hepatitis C virus (HCV)-related cirrhosis, recurrence of HCV infection is universal. The efficacy of antiviral therapy in this indication is usually reduced because of its poor tolerability. We present herein the results of plasma measurement of ribavirin levels in transplanted patients when using increasing dosage of ribavirin, in comparison with a control cohort of nontransplanted patients. Seventeen control patients (nine women and eight men, median age 51.5 years) were compared with 12 liver transplant patients (2 women and 10 men, median age 55 years). In 76% of patients, HCV infection was genotype 1. All patients were treated by a combination of ribavirin and pegylated-interferon alpha-2b. A total of 54 blood samples were taken (1.8 per patient) for ribavirin level measurement. A virological response was obtained in 8/17 patients in the control group and in 6/12 LT patients. Ribavirin dose was lower in the LT group (8.79 vs 12.98 mg/kg/day), but plasma levels were the same in both groups (2.23 vs 2.43 mg/L for LT and non-LT groups, respectively). This was probably related to impaired renal function in the LT group (serum creatinine: 112.6 vs 73.6 micromol/L). No discontinuation of ribavirin therapy was observed and haemoglobin level was the same in both groups (109.5 g/L in LT patients vs 119.5 g/L in the control group). These results strongly support the interest in plasma measurement of ribavirin concentration during antiviral therapy in LT patients. Ribavirin dosage might be adapted without compromising its efficacy.

Alanine Transaminase↗
PubMed2006

Favorable outcome of liver transplantation despite a high hepatitis B virus replication: beyond the limits?

Patients with end-stage liver disease due to chronic hepatitis B virus (HBV) infection with a persistent viral replication are generally denied liver transplantation (LT). We report the case of a patient who presented with the emergence of a YMDD escape mutant virus under lamivudine treatment, and developed terminal liver failure requiring LT. Pre-LT introduction of adefovir led to only a mild decrease in replication. The patient was treated with a combination of intravenous hepatitis B immune globulin (HBIG) that was started perioperatively, and also continued lamivudine and adefovir after LT. One year after LT, there was no evidence of HBV infection recurrence. This observation suggests that persistent high HBV replication might not be a contra-indication to LT, providing adequate and effective prophylaxis is given, using HBIG and antiviral drug combination therapy.

Adenine↗
PubMed2005

[Radiofrequency tumor ablation: from the liver to the lung passing by the kidney].

Tumor ablation using radiofrequency technique is an interventional radiology method for the treatment of liver renal or pulmonary tumors. The size of the lesion is the limiting factor of this technique. Tumors below 3 cm are treated with a 90% efficacy in one session. Complications are variable according to the organ treated.

Catheter Ablation↗
PubMed2005

Improving arterial prosthesis neo-endothelialization: application of a proactive VEGF construct onto PTFE surfaces.

The formation of a confluent endothelium on expanded polytetrafluoroethylene (PTFE) vascular prostheses has never been observed. This lack of endothelialization is known to be one of the main reasons leading to the development of thromboses and/or intimal hyperplasia. In this context, several efforts were put forward to promote endothelial cell coverage on the internal surface of synthetic vascular prostheses. The goal of the present study was to immobilize the vascular endothelial growth factor (VEGF) onto Teflon PTFE surfaces to generate a proactive polymer construct favoring interaction with endothelial cells. An ammonia plasma treatment was first used to graft amino groups on PTFE films. Subsequent reactions were performed to covalently bind human serum albumin (HSA) on the polymer surface and to load this protein with negative charges, which allows adsorbtion of VEGF onto HSA via strong electrostatic interactions. X-ray photoelectron spectroscopy (XPS) experiments along with surface derivatization strategies were performed between each synthesis step to ascertain the occurrence of the various molecules surface immobilization. Finally, the electrostatic binding of VEGF to the negatively charged HSA matrix was performed and validated by ELISA. Endothelial cell adhesion and migration experiments were carried out to validate the potential of this VEGF-containing biological construct to act as a proactive media toward the development of endothelial cells.

Adsorption↗
PubMed2005

Changing of hepatitis C virus genotype patterns in France at the beginning of the third millenium: The GEMHEP GenoCII Study.

This cross-sectional study aimed to investigate, during a short period between 2000 and 2001, in a large population of patients with chronic hepatitis C, the epidemiological characteristics of hepatitis C virus (HCV) genotypes in France. Data from 26 referral centres, corresponding to 1769 patients with chronic hepatitis C were collected consecutively during a 6-month period. HCV genotyping in the 5'-non-coding region (NCR) was performed in each center using the line probe assay (LiPA, in 63% of cases), sequencing (25%) or primer-specific polymerase chain reaction (PCR) (12%). HCV genotypes 1a, 1b, 2, 3, 4, 5, non-subtyped 1 and mixed infection were found in 18, 27, 9, 21, 9, 3, 11 and 1% of our population, respectively. HCV genotype distribution was associated with gender, age, source and duration of infection, alanine aminotransferase (ALT) levels, cirrhosis, alcohol consumption, hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection. In multivariate analysis, only the source of infection was the independent factor significantly associated with genotype (P = 0.0001). In conclusion, this study shows a changing pattern of HCV genotypes in France, with i.v. drug abuse as the major risk factor, an increase of genotype 4, and to a lesser extent 1a and 5, and a decrease of genotypes 1b and 2. The modification of the HCV genotype pattern in France in the next 10 years may require new therapeutic strategies, and further survey studies.

Adult↗
PubMed2005

Intrahepatic CD4 T-Cell apoptosis is related to METAVIR score in patients with chronic hepatitis C virus.

Hepatitis C virus (HCV) infection leads to liver injury, which is thought to be immune-mediated. Apoptosis of hepatic T cells could influence histological damage. We quantified peripheral and intrahepatic T-cell apoptosis in 28 patients with chronic hepatitis C by using cytofluorometric techniques. METAVIR score and HCV plasma viral load were determined. Six liver biopsies, obtained from controls without chronic hepatitis during hepatobiliary surgery, served as controls. In patients, liver T-cell apoptosis was upregulated compared to peripheral T cells: 35 versus 7% for CD4+ and 56 versus 13% for CD8+ T cells (P < 0.001). Liver T-cell apoptosis levels from patients were increased compared to controls for both CD4+ (P = 0.041) and CD8+ T cells (P = 0.007). Nine patients exhibiting METAVIR scores A and F < or = 1 showed higher intrahepatic CD4+ T-cell apoptosis compared to the 19 patients with a higher METAVIR score (P = 0.001) and both histological activity and fibrosis were related to apoptosis level. There was also an inverse relationship between the level of intrahepatic CD8+ T-cell apoptosis and serum transaminase activity (P = 0.023). Our study shows immune compartmentalization, suggesting that the study of peripheral blood lymphocytes may not be fully relevant to the pathophysiology of HCV hepatitis, and that the severity of liver injury is inversely correlated with intrahepatic CD4+ T-cell apoptosis.

Adult↗
PubMed2004

[Value of CT in small-bowel obstruction].

Small bowel obstruction is a leading cause of admission in surgical and emergency units. During the last two decades, the classical philosophy of "never let the sun set or rise on small-bowel obstruction" has been succeeded by a new management based especially on the cause and the severity of the obstruction. It most often allows a correct choice between medical therapy and surgery using laparotomy or laparoscopy. This changing attitude is still in progress and is mainly related to the high accuracy of computed tomography. This review will discuss the semiology and value of computed tomography compared with clinical examination and other imaging modalities.

Humans↗
PubMed2004

Localization of transforming growth factors, TGFbeta1 and TGFbeta3, in hypothalamic magnocellular neurones and the neurohypophysis.

The distribution of transforming growth factor beta (TGFbeta) in the rat and human hypothalamus and neurohypophysis was investigated by immunocytochemical techniques using rabbit polyclonal antisera against TGFbeta(1) and TGFbeta(3). Colocalization of TGFbeta(1) or TGFbeta(3) and arginine vasopressin (AVP) in the rat hypothalamus was studied by double immunolabelling in light microscopy, while their subcellular localization in the rat neurohypophysis was investigated by immunoelectron microscopy. TGFbeta(1) and TGFbeta(3) immunoreactivity was demonstrated in the cell bodies and processes of neurones in the supraoptic nucleus (SON) and paraventricular nucleus (PVN). The TGFbeta-immunoreactive cells were more numerous in the SON compared to the PVN. TGFbeta/AVP double-labelled cells were seen in both nuclei, but some neurones in the SON were labelled for TGFbeta(1) or TGFbeta(3), although not for AVP. In the rat and human neurohypophysis, TGFbeta(3) immunolabelling was more diffuse and stronger than TGFbeta(1) immunolabelling. TGFbeta(1) expression was seen in axonal vesicles and in neurosecretory granules of the axonal endings, while TGFbeta(3) was observed in axonal fibres. Colocalization of TGFbeta(3) or TGFbeta(1) and AVP was observed in some neurosecretory granules, but many were either single-labelled for TGFbeta or AVP or unlabelled. Our results demonstrate, for the first time, the colocalization of TGFbeta and neurohypophysial hormones in magnocellular neurones. We suggest that TGFbeta secreted by the neurohypophysis regulates the proliferation and secretion of certain anterior pituitary cells.

Animals↗
PubMed2004

Survival in HIV-infected patients is associated with hepatitis C virus infection and injecting drug use since the use of highly active antiretroviral therapy in the Lyon observational database.

Highly active antiretroviral therapy (HAART) has reduced the incidence of death in HIV-infected patients but various rates of survival have been reported due to the infection with hepatitis C virus (HCV) and the use of injecting drugs (IDU). A survival analysis was performed to estimate and compare the death rates in HIV-positive patients infected by IDU and/or positive for HCV antibodies in the pre-HAART and HAART periods in Lyon (France) between 1992 and 2002. Patients were stratified into four groups (G): HCV-/IDU-(G1), HCV+/IDU-(G2), HCV+/IDU-(G3), HCV+/IDU+ (G4) and adjusted death rates in the pre-HAART era (< 1996) and the HAART era (> or = 1996) were compared. The aHR of progression to death was 1.05 (95% CI 0.75-1.47, P = 0.75) for G2, 1.09 (95% CI 0.54-2.22, P = 0.81) for G3 and 0.90 (95% CI 0.65-1.24, P =0.51) for G4 compared with G1 in the pre-HAART era. The aHR of progression to death was 0.76 (95% CI 0.28-2.08, P = 0.59) for G2, 1.23 (95% CI 0.17-8.86, P = 0.84) for G3 and 2.90 (95% CI 1.62-5.20, P < 0.001) for G4, compared with G1 in the HAART era. HAART management of HCV+/IDU+ patients needs to be optimized for them to achieve a similar benefit as observed among other individuals.

Adult↗
PubMed2004

A multicenter survey on anaesthesia practice in Italy.

AIM: To achieve more information on anaesthesia practice in Italy. METHODS: One questionnaire was completed for every anaesthetic procedure performed during the last week of June 1999 in 162 public hospitals selected in the northern, central and southern parts of Italy. RESULTS: A total of 12 263 anaesthetic procedures were performed during the study week in participating hospitals, extrapolating to 4 905200 anaesthetic procedures performed in Italy in 1999 (95% confidence interval, (+/-245000), with an annual rate of 8.5 anaesthetic procedures per 100 population. Children represented 12%, adults 60%, and elderly patients 28% of all studied patients. Emergency procedures were performed in 14% of cases; only 14% of cases were outpatients, but 31% of patients were discharged within 48 h after surgery. General anaesthesia was used in 65% of cases (45% volatile and 20% intravenous anaesthesia), regional anaesthesia in 24%, local anaesthesia in 8.8% and monitored anaesthesia care in 2.2%. No differences in the distribution of anaesthesia techniques were observed according to the geographic region or hospital size. CONCLUSION: Some organizational problems still remain to be implemented, including the development of proper preoperative evaluation clinics and postanaesthesia care units, especially in bigger hospitals with more than 1 000 beds.

Adolescent↗
PubMed2003

Long term histological improvement and clearance of intrahepatic hepatitis C virus RNA following sustained response to interferon-ribavirin combination therapy in liver transplanted patients with hepatitis C virus recurrence.

BACKGROUND AND AIMS: A proportion of liver transplanted patients with recurrent chronic hepatitis have a sustained virological response to combination therapy with interferon plus ribavirin. However, the long term benefit of antiviral therapy with regard to hepatitis C virus (HCV) RNA clearance remains unknown in patients with HCV recurrence. This study examined the long term biochemical, virological, and histological outcome in transplanted patients with recurrent chronic hepatitis who had a sustained virological response to antiviral therapy. PATIENTS AND METHODS: Fifty four patients with recurrent hepatitis C were treated with antiviral therapy involving induction by combination therapy (interferon (IFN) plus ribavirin) for six months and maintenance ribavirin therapy for 12 months. Fourteen patients who had recurrent chronic hepatitis and sustained virological response to antiviral therapy were followed for three years after the end of antiviral therapy. Serum alanine aminotransferases were assessed every three months during the observation period. Serum hepatitis C RNA detected by polymerase chain reaction was evaluated every six months during follow up, and protocol biopsy procedures were performed routinely every year. Semiquantitative histopathological assessment of allograft hepatitis was performed using the Knodell score and HCV was also detected by polymerase chain reaction on frozen graft tissue samples. RESULTS: At the end of antiviral therapy, the sustained response rate was 26%. A complete response (normal serum alanine aminotransferase level and undetectable serum HCV RNA) was achieved in 13/14 (93%) patients three years after the end of treatment. A comparison of liver histology findings before and after a mean of three years after antiviral therapy showed a clear improvement in 12/14 (86%) patients. In 5/14 (36%) patients, the last biopsy showed normal or near normal histological findings. After three years of follow up, the total Knodell score was 3.2 (range 1-8) versus 8.3 (range 5-12) before treatment (p=0.001). Graft HCV RNA was detectable before treatment in all 14 patients and was undetectable at the end of follow up in 13/14 (93%) patients tested. CONCLUSION: In patients with biochemical and virological responses induced by ribavirin and interferon, a complete response was sustained in 93% for at least three years after cessation of therapy. This long term response was associated with absence of detectable intrahepatic hepatitis C RNA and marked histological improvement.

Adult↗