169,927 research outputs found
Hepatic flares in chronic hepatitis C: Spontaneous exacerbation vs hepatotropic viruses superinfection
No full textThe hepatitis C virus (HCV) causes an acute infection that is frequently asymptomatic, but a spontaneous eradication of HCV infection occurs only in one-third of patients. The remaining two-thirds develop a chronic infection that, in most cases, shows an indolent course and a slow progression to the more advanced stages of the illness. Nearly a quarter of cases with chronic hepatitis C (CHC) develop liver cirrhosis with or without hepatocellular carcinoma. The indolent course of the illness may be troubled by the occurrence of a hepatic flare, i.e., a spontaneous acute exacerbation of CHC due to changes in the immune response, immunosuppression and subsequent restoration, and is characterized by an increase in serum aminotransferase values, a frequent deterioration in liver fibrosis and necroinflammation but also a high frequency of sustained viral response to pegylated interferon plus ribavirin treatment. A substantial increase in serum aminotransferase values during the clinical course of CHC may also be a consequence of a superinfection by other hepatotropic viruses, namely hepatitis B virus (HBV), HBV plus hepatitis D virus, hepatitis E virus, cytomegalovirus, particularly in geographical areas with high endemicity levels. The etiology of a hepatic flare in patients with CHC should always be defined to optimize follow-up procedures and clinical and therapeutic decisions. © 2014 Baishideng Publishing Group Inc. All rights reserved
Clinical applications of antibody avidity and immunoglobulin M testing in acute HCV infection
No full textAcute hepatitis C is often asymptomatic, frequently remains undiagnosed and frequently evolves to chronic hepatitis. Early, short-term interferon treatment is efficacious in acute hepatitis C, and so underscores the importance of an early diagnosis and the need to distinguish acute infection from acute exacerbation of chronic HCV infection. The gold standard for the diagnosis of acute hepatitis C is demonstration of conversion to anti-HCV positivity, HCV RNA positivity or both, events that frequently occur before the patient comes to medical attention. Several laboratory approaches to assist with early diagnosis of acute hepatitis C have been developed. Our studies, reviewed here, show that testing for antibody avidity and anti-HCV immunoglobulin M allow diagnosis in up to 90% of cases of acute hepatitis C. ©2012 International Medical Press
Hepatitis c virus markers in infection by hepatitis c virus:In the era of directly acting antivirals
No full textAbout 130-170 million people are infected with the hepatitis C virus (HCV) worldwide and more than 350000 people die each year of HCV-related liver diseases. The combination of pegylated interferon (Peg-IFN) and ribavirin (RBV) was recommended as the treatment of choice for chronic hepatitis C for nearly a decade. In 2011 the directly acting antivirals (DAA) HCV NS3/4A protease inhibitors, telaprevir and boceprevir, were approved to treat HCV-genotype-1 infection, each in triple combination with Peg-IFN and RBV. These treatments allowed higher rates of SVR than the double Peg-IFN+ RBV, but the low tolerability and high pill burden of these triple regimes were responsible for reduced adherence and early treatment discontinuation. The second and third wave DAAs introduced in 2013-2014 enhanced the efficacy and tolerability of anti-HCV treatment. Consequently,the traditional indicators for disease management and predictors of treatment response should be revised in light of these new therapeutic options. This review article will focus on the use of the markers of HCV infection and replication, of laboratory and instrumental data to define the stage of the disease and of predictors, if any, of response to therapy in the DAA era. The article is addressed particularly to physicians who have patients with hepatitis C in care in their everyday clinical practice
Simulation of engagement control in automotive dry-clutch and temperature field analysis through finite element model
No full textThe tribological contact under sliding condition in the clutch facing surfaces during the engagement manoeuvre is strongly affected by heat transfer occurring in the system. The frictional forces acting on the contact surfaces produce mechanical energy losses which are converted in heat with ensuing temperature increase. Reports about the temperature rise after repeated clutch engagements prove the occurrence
of interface temperature peaks as high as 300 °C. Unfortunately, only few papers address their focus towards experiments and their outcomes about the influence of temperature and the other operating parameters on the frictional behaviour of the clutch facing materials.
In this paper, the Authors mainly explored the frictional behaviour modification for thermal level higher than 250–300 °C, whose effect is a sharp decline of the friction coefficient related to the decomposition of the phenol resin of the facings. Moreover, this phenomenon induces not expected transition from dry friction to mixed dry-lubricated friction which explains the reasons of the friction coefficient drop. The
temperature affects also the cushion spring load-deflection characteristic and the ensuing transmitted clutch torque. Thus, an original frictional map has been implemented in a control algorithm to estimate the heat flux during vehicle launch and up-shift manoeuvres. The results of the longitudinal vehicle dynamics has been used in a FEA to predict the temperature field during repeated clutch engagement on
the contact surfaces. The simulation results prove that during each engagement the interface temperature increases of 30–35 °C. This means that after only few repeated clutch engagements the temperature field could reach values near the critical point of 300 °C. In such a way, this paper aims at providing useful references to control engineers in order to improve the dry-clutch transmissions performances
Role of genetic polymorphisms in hepatitis C virus chronic infection
No full textTo analyze the host genetics factors influencing the clinical course and the response to antiviral treatment in patients with chronic hepatitis C (CHC)
Epidemiology and management of hepatitis C virus infections in immigrant populations
No full textAbstract Background At present, there is a continuous flow of immigrants from the south of the world to north-western countries. Often immigrants originate from areas of high-prevalence of viral hepatitis and pose a challenge to the healthcare systems of the host nations. Aims of this study is to evaluate the prevalence and virological and clinical characteristics of hepatitis C virus (HCV) infection in immigrants and the strategies to identify and take care of the immigrants infected with HCV. Main body We conducted an electronic literature search in several biomedical databases, including PubMed, Google Scholar, Scopus, Web of Science, using different combinations of key words: “HCV infection; chronic hepatitis C, immigrants; low-income countries”. We included studies written in English indicating the epidemiological data of HCV infection in the immigrant population, studies that assessed the clinical presentation, clinical management and treatment with directly acting antiviral agent in immigrants, HCV infection is unevenly distributed in different countries, with worldwide prevalence in the general population ranging from 0.5 to 6.5%. In Western countries and Australia this rate ranges from 0.5 to 1.5%, and reaches 2.3% in countries of south-east Asia and eastern Mediterranean regions, 3.2% in China, 0.9% in India, 2.2% in Indonesia and 6.5% in Pakistan; in sub-Saharan Africa the prevalence of HCV infection varies from 4 to 9%. Immigrants and refugees from intermediate/high HCV endemic countries to less- or non-endemic areas are more likely to have an increased risk of HCV infection due to HCV exposure in their countries of origin. Because of the high HCV endemicity in immigrant populations and of the high efficacy of directly acting antiviral agent therapy, a campaign could be undertaken to eradicate the infection in this setting. Conclusions The healthcare authorities should support screening programs for immigrants, performed with the help of cultural mediators and including educational aspects to break down the barriers limiting access to treatments, which obtain the HCV clearance in 95% of cases and frequently prevent the development of liver cirrhosis and hepatocellular carcinoma
Efficacy of pegylated interferon α-2a and α-2b in patients with genotype 1 chronic hepatitis C: a meta-analysis
No full textAbstract Background Two formulations of Pegylated interferon (Peg-IFN) are on the market for treatment of chronic hepatitis C virus (HCV) infection. The purpose of this meta-analysis was to assess the efficacy of Peg-IFN α-2a versus Peg-IFN α-2b in combination with ribavirin in anti-human immunodeficiency virus (HIV)-negative patients with genotype 1 chronic HCV infection. Methods The following criteria were to be met for inclusion in the meta-analysis: (a) original data from randomized and non-randomized clinical trials; (b) study on the efficacy of conventional doses of Peg-IFN α-2a (180 μg/week) versus Peg-IFN α-2b (1.5 μg/kg of body weight/week), both in combination with ribavirin, in antiviral therapy-naïve HCV-genotype 1 subjects; (c) at least one of these primary outcomes: Rapid Virological Response (RVR); Early Complete Virological Response (EVR); End of Treatment Response (ETR); Sustained Virological Response (SVR); (d) odds ratio estimates of relative risk (RR) and associated 95% confidence intervals (CIs) or at least data enabling them to be computed; (e) English language; and (f) published as a full paper up to December 2011. Results Seven published studies met the inclusion criteria, allowing a meta-analysis on 3,026 patients. Peg-IFN α-2a and Peg-IFN α-2b showed similar rate of RVR (RR = 1.05; 95% CI = 0.87-1.27, p = 0.62) and SVR (RR = 1.08; 95% CI = 0.99-1.18, p = 0.098). Peg-IFN α-2a more frequently than Peg-IFN α-2b achieved EVR (RR = 1.11; 95% CI = 1.02-1.21, p = 0.013) and ETR (RR = 1.22; 95% CI = 1.14-1.31, p Conclusion The standard schedules of Peg-IFN α-2a and Peg-IFN α-2b, both in combination with ribavirin, can be used indifferently for patients with chronic HCV genotype 1 who are anti- to eliminate HIV-negative and antiviral treatment-naïve.</p
Acute hepatitis C: clinical and laboratory diagnosis, course of the disease, treatment.
No full textAbstract
INTRODUCTION:
Acute hepatitis C (AHC) is asymptomatic in about 70-80 % of cases and, therefore, is usually undiagnosed. Although the clinical course is typically mild, AHC has a high rate of transition to chronicity.
MATERIAL AND METHODS:
We evaluated the literature data concerning risk factors for HCV transmission, diagnosis, natural history, and antiviral treatment of AHC.
RESULTS:
Although new methods have been developed, anti-HCV seroconversion remains the gold standard for the diagnosis of AHC. This phenomenon, however, is identifiable in less than half of cases in the everyday clinical practice, since most AHC patients do not know their previous anti-HCV/HCV-RNA status. An early short-term interferon treatment in AHC patients prevents progression to chronicity in most of treated patients.
CONCLUSION:
The literature data give evidence of the clinical relevance of an early diagnosis of AHC for an early short-term interferon treatment. There is also the suggestion to use newly developed laboratory methods to distinguish AHC from an acute exacerbation of a chronic HCV infection
Clinical and virological improvement of hepatitis B virus-related or hepatitis C virus-related chronic hepatitis with concomitant hepatitis A virus infection
No full textBackground. We evaluated the clinical and virological characteristics of hepatitis A virus infection in persons concomitantly infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). Methods. We enrolled 21 patients with acute hepatitis A and chronic hepatitis with no sign of liver cirrhosis, 13 patients who were positive for hepatitis B surface antigen (case B group), 8 patients who were anti-HCV positive (case C group), and 21 patients with acute hepatitis A without a preexisting liver disease (control A group). Two control groups of patients with chronic hepatitis B (control B group) or C (control C group) were also chosen. All control groups were pair-matched by age and sex with the corresponding case group. Results. Fulminant hepatitis A was never observed, and hepatitis A had a severe course in 1 patient in the case B group and in 1 patient in the control A group. Both patients recovered. On admission, HBV DNA was detected in 1 patient in the case B group (7.7%) and in 13 patients (50%) in the control B group; HCV RNA was found in no patient in the case C group and in 16 patients (81.2%) in the control C group. Of 9 patients in the case B group who were followed up for 6 months, 3 became negative for hepatitis B surface antigen and positive for hepatitis B surface antibody, 2 remained positive for hepatitis A surface antigen and negative for HBV DNA, and 4 became positive for HBV DNA with a low viral load. Of 6 patients in the case C group who were followed up for 6 months, 3 remained negative for HCV RNA, and 3 had persistently low viral loads. Conclusion. Concomitant hepatitis A was always self-limited, associated with a marked inhibition of HBV and HCV genomes, and possibly had a good prognosis for the underlying chronic hepatitis. © 2006 by the Infectious Diseases Society of America. All rights reserved
Liver fibrosis in human immunodeficiency virus/hepatitis C virus coinfection: Diagnostic methods and clinical impact
No full textSeveral non-invasive surrogate methods have recently challenged the main role of liver biopsy in assessing liver fibrosis in hepatitis C virus (HCV)-monoinfected and human immunodeficiency virus (HIV)/HCV-coinfected patients, applied to avoid the well-known side effects of liver puncture. Serological tests involve the determination of biochemical markers of synthesis or degradation of fibrosis, tests not readily available in clinical practice, or combinations of routine tests used in chronic hepatitis and HIV/HCV coinfection. Several radiologic techniques have also been proposed, some of which commonly used in clinical practice. The studies performed to compare the prognostic value of noninvasive surrogate methods with that of the degree of liver fibrosis assessed on liver tissue have not as yet provided conclusive results. Each surrogate technique has shown some limitations, including the risk of over- or under-estimating the extent of liver fibrosis. The current knowledge on liver fibrosis in HIV/HCV-coinfected patients will be summarized in this review article, which is addressed in particular to physicians involved in this setting in their clinical practice
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