Hepatitis C screening strategies in hemodialysis patients.

Hepatitis C virus (HCV) infection is common in patients undergoing chronic hemodialysis, with an estimated yearly incidence of 0.2% and prevalence between 8% and 10%. Although a screening strategy based on alanine aminotransferase (ALT) values is currently recommended, this strategy has not been evaluated for cost-effectiveness compared with other potential screening strategies. A comparison therefore was made using a decision-analysis model of a simulated cohort of 5,000 hemodialysis patients followed up for 5 years. Using direct medical costs, three strategies were evaluated, including: (1) ALT values with confirmatory testing (biochemical), (2) serial enzyme-linked immunosorbent and strip immunoblot assay testing (serological), and (3) polymerase chain reaction (viral). Under baseline assumptions, the per-patient cost of screening hemodialysis patients for HCV was $378 for biochemical-based testing, $195 for serological-based testing, and $696 for viral-based testing. Our model was robust when varying the costs of testing, as well as the incidence and prevalence of HCV infection. Results of sensitivity analysis by varying costs, HCV incidence, and HCV prevalence indicated that serological-based screening was less costly than biochemical testing. Biochemical testing was in turn less costly than viral-based screening. Serological-based testing was also more effective in the diagnosis of de novo HCV infection, with a likelihood ratio of 85, in contrast to the likelihood ratio of 44 with biochemical-based testing using viral-based screening as the gold standard. A serological-based screening strategy is less costly and more effective than biochemical-based screening in the diagnosis of de novo HCV infection. Serological-based screening should be considered for HCV screening in hemodialysis populations.

Automated RIBA HCV strip immunoblot assay: a novel tool for the diagnosis of hepatitis C virus infection in hemodialysis patients.

Hemodialysis (HD) patients remain a high-risk group for hepatitis C virus (HCV) infection. Serological assays (enzyme-linked immunosorbent assays, ELISAs) are the only tests currently approved by the Food and Drug Administration in the United States for the diagnosis of HCV. The RIBA HCV Strip Immunoblot Assay (SIA) is an established method for supplemental testing of repeat reactive hepatitis C ELISA patients on HD. However, the current manual procedure is labor intensive, requiring subjective band scoring and result interpretation. Recently, the automated CHIRON RIBA HCV Processor System has been designed to perform RIBA supplemental testing. The CHIRON RIBA HCV Processor System consists of a bench-top instrument that provides objective evaluation of the RIBA immunoblot strips, by measuring the light differentially reflected from the developed bands and white background, creating a density of reflectance. The CHIRON RIBA HCV Processor System assesses the intensity of each of the reactive bands in relation to the intensity of the internal control bands on each RIBA HCV strip. Comparison between processor and manual protocols was performed using a large (n = 200) cohort of ELISA 3.0 HCV negative and positive patients on maintenance HD. The test characteristics of RIBA HCV 3.0 SIA were identical with manual and automated runs. The relative intensity values of antigenic bands by the CHIRON RIBA HCV 3.0 Processor System between anti-HCV positive and negative patients were significantly different; only 15 of 784 (1.9%) antigenic bands had borderline reactivities. The correlation of test results between manual and automated runs was very high (kappa value 0.989). Among positive results by RIBA HCV 3.0 SIA, there was a strong concordance between manual and automated runs with regard to the pattern of reactivity (kappa value 0.943). The discordant results between manual and automated protocols were attributable to increased variability of antigen scores close to the cutoff value for both tests. In conclusion, the CHIRON RIBA HCV 3.0 Processor System is capable of performing RIBA HCV 3.0 SIA in the HD population accurately with minimal operator involvement. The test characteristics of RIBA HCV 3.0 SIA were identical by manual and automated runs. There was a strong correlation between the results of the manual and automated runs; the few discordant results between the two procedures were mostly due to increased variability of antigen scores close to the cutoff value for both tests. The Centers for Disease Control and Prevention in the USA have recently included chronic HD patients among those persons for whom routine HCV testing is recommended; HCV-infected patients on HD often have a high rate of indeterminate results by manual RIBA technology which is operator dependent for band scoring and result interpretation. The CHIRON RIBA HCV 3.0 Processor System may be very useful for supplemental anti-HCV testing of ELISA repeat reactive specimens in clinical practice within dialysis units.

Serum alanine aminotransferase in hepatitis c screening of patients on hemodialysis.

It is recommended that patients on hemodialysis (HD) therapy undergo regular screening for hepatitis C virus (HCV) infection by using alanine aminotransferase (ALT) values. However, the utility of using ALT values in this setting is unknown. The aim of this prospective study at the University of California Los Angeles Hepatitis Screening Program is to determine the sensitivity, specificity, and predictive values of an elevated ALT level for the diagnosis of HCV infection in HD patients. We screened 2,440 HD patients from 39 dialysis centers for viral infection by using hepatitis antibody serological testing and ALT values. We found the sensitivity and specificity of a newly elevated ALT level for acute HCV infection to be 83% and 90%, respectively. According to Bayes' theorem, the positive predictive value was 4% and the positive likelihood ratio was 8.74. For chronic HCV infection, the sensitivity of a newly elevated aminotransferase level was 21%, and specificity was 91%. The positive predictive value was 16% (according to Bayes' theorem), and the positive likelihood ratio was 2.47. The negative predictive value of a newly elevated aminotransferase value was 99% for acute HCV infection and 94% for chronic HCV infection. Our results indicate that although a newly elevated aminotransferase level is sensitive and specific for acute HCV infection, its positive predictive value is inadequate. A newly elevated aminotransferase level was neither sensitive nor positively predictive of chronic infection. Therefore, an elevated ALT level is an ineffective method for screening for HCV infection in HD patients.

Serotyping strip immunoblot assay for assessing hepatitis C virus strains in dialysis patients.

Recent accumulated evidence shows that dialysis patients are a high-risk group for hepatitis C virus (HCV) infection. Assessment of HCV genotype distribution among dialysis patients may be important because specific viral genotypes are associated with different clinical manifestations, disease progression, and response to antiviral therapy. However, polymerase chain reaction-based methods are cumbersome and unsuitable for analyzing large cohorts of dialysis patients with HCV. Instead, this information can be obtained by using a novel recombinant immunoblot assay (RIBA) recently developed for determining HCV serotype. The RIBA HCV serotyping strip immunoblot assay (SIA; Chiron Corporation, Emeryville, CA), is based on an immunoblot strip with five lanes of immobilized serotype-specific HCV peptides from the nonstructural (NS4) and core regions of the genomes of HCV types 1, 2, and 3. HCV serotype is deduced by determining the greatest intensity of reactivity to the NS4 serotype-specific HCV peptide band in relation to the internal control band (human immunoglobulin G) intensity on each strip. HCV core peptide reactivity is used only in the absence of NS4 reactivity. We compared RIBA HCV serotyping SIA with genotyping using sera from a large (n = 107) cohort of HCV-infected patients undergoing chronic hemodialysis (HD). We successfully serotyped 79 of 107 patients (74%) undergoing HD. We found a remarkable concordance (65 of 70 results; 93%) between RIBA HCV serotyping SIA and genotyping (line probe assay [LiPA]) techniques (kappa = 0.786) with sera from viremic patients infected with a known genotype. Only 5 of 70 patients (7%) had apparently discordant results. In a subset of patients (28 of 107 patients; 26%) not typed by RIBA HCV serotyping SIA, most (24 of 28 patients; 86%) were successfully genotyped by LiPA technology. It was possible to assess serotype reactivity in some patients (9 of 107 patients; 7%) who could not be genotyped. The distribution of HCV serotypes was associated with the antibody response against HCV proteins and the patterns of reactivity by RIBA HCV 2.0 SIA. In conclusion, (1) we found good agreement between serotyping and genotyping methods in our large cohort of dialysis patients infected with HCV; (2) the impaired immunocompetence conferred by uremia may limit serotyping analysis in some HCV-infected patients undergoing HD; (3) RIBA HCV serotyping SIA may be useful in tracking transmission routes for HD patients who cleared the virus and have only anti-HCV antibody; and (4) the distribution of HCV serotypes was associated with the antibody response against HCV proteins and the patterns of reactivity by RIBA HCV 2.0 SIA. Assessment of HCV strains appears to be very useful in the routine clinical activity of nephrologists within HD units because consistent biological differences among HCV strains exist. RIBA serotyping SIA is a simple, inexpensive, and highly reproducible assay to obtain information about HCV types in the HD setting.

Biological dynamics of viral load in hemodialysis patients with hepatitis C virus.

The biological dynamics of hepatitis C virus (HCV) viremia in uremic patients with chronic infection have not been fully characterized. We prospectively studied fluctuations of HCV-RNA in sera from 52 patients with end-stage renal disease who were undergoing maintenance hemodialysis (HD) and had chronic HCV infection. We measured HCV viremia monthly over the course of 13 months with the branched-chain DNA (bDNA) signal amplification assay and prospectively analyzed liver function, expressed by monthly serum aspartate (AST) and alanine aminotransferase (ALT) determinations. We observed three different patterns of HCV viremia: (1) patients persistently positive by bDNA assay (persistent viremia; 23 of 52 patients; 44%), (2) individuals with alternatively positive and negative results (intermittent viremia; 17 of 52 patients; 33%), and (3) patients persistently negative by bDNA assay (12 of 52 patients; 23%). The HCV viral load over the follow-up was greater among patients with persistent compared with intermittent viremia (persistent, 31.7 x 10(5) Eq/mL; range, 6.3 x 10(5) to 16.03 x 10(6) Eq/mL versus intermittent, 10.4 x 10(5) Eq/mL; range, 1.1 x 10(5) to 9.4 x 10(6) Eq/mL; P = 0.0001). In addition, patients with persistent viremia had over time greater AST and/or ALT activities than the intermittent group (AST: persistent, 26.5 IU/L; range, 9.6 to 73.7 IU/L versus intermittent, 21.3 IU/L; range, 8 to 56.8 IU/L; P = 0.001 and ALT: persistent, 14.7 IU/L; range, 3.7 to 57.9 IU/L versus intermittent, 10.9 IU/L; range, 2.3 to 52.1 IU/L; P = 0.001). In the group with persistent viremia, the mean difference between maximum and minimum values of HCV-RNA observed in each individual patient was 2.09 +/- 0.7 natural logarithm (Log(n)) and in intermittent viremic patients, 1.55 +/- 1 Log(n) (P = 0.045). The HCV load at study entry (19.4 x 10(5) Eq/mL) was rather low and did not change versus the end of follow-up in all patients (P = not significant [NS]). In the entire group, the fluctuations in HCV-RNA levels over time between and within individuals were not significant (P = NS). No difference in variability of HCV-RNA values over time between patients infected with different HCV genotypes was seen. In conclusion, three different patterns of HCV viremia in HD over time were assessed; one third of viremic patients had intermittent viremia, and those patients had less HCV-RNA, enzyme-linked immunosorbent assay, and aminotransferase activity than did patients with persistent HCV load. Larger fluctuations in HCV RNA levels occurred in patients with persistent than with intermittent HCV viremia. However, the viremic HCV load was low and relatively stable over a 13-month follow-up in our population. Studies with longer observation periods are warranted to understand fully the natural history of HCV in these immunosuppressed individuals.

Epidemiology and natural history of hepatitis G virus infection in chronic hemodialysis patients.

UNLABELLED: Patients on chronic hemodialysis (HD) have recently been identified as having a high prevalence of hepatitis G virus (HGV) infection. The clinical significance of HGV in this population remains unclear, with no data available as to the acquisition and natural history of HGV infection in this group. AIMS: To assess the prevalence and risk factors of HGV in a large cohort of chronic HD patients, and to evaluate the incidence and clinical consequences of HGV over time in this population. METHODS: Paired sera from 292 patients undergoing chronic HD treatment in four units in the Los Angeles area were tested for HGV RNA before and after they had been on HD for a mean period of 9.7 +/- 1.9 months. HGV was tested by a single-step RT-PCR using two couples of primers located in two different portions (5'UTR, NS5a) of the genome. The amplified products were detected by hybridization with 5' biotin-labeled probes specific for each region. RESULTS: At study entry there were 50 HGV RNA-positive patients, thus the HGV prevalence was 17% (50/292). The multivariate analysis by ordinal logistic regression model showed association (p = 0.0013) between HGV RNA and the location of patients among the HD units. No other significant associations were observed. Three (3/50 = 6%) HGV RNA-positive patients at study entry and 3 (3/41 = 7%) at the end of the follow-up showed a mild increase of alanine aminotransferase (ALT) activity in absence of other apparent causes of liver damage. 35 (70%) out of 50 HGV viremic patients had persistently detectable viremia during the study period; 15 (30%) had non-persistently detectable HGV RNA in the second serum specimen. There was no significant difference between the patients with persistently detectable HGV RNA and those who showed non-persistently detectable HGV viremia with regard to demographic, clinical or virological features. Six patients without detectable HGV viremia at the start of the study showed de novo HGV infection during the follow-up, thus the HGV incidence was 3.07% per year. These individuals did not simultaneously acquire HBV or HCV markers; de novo HGV infection was not associated with other demographic, clinical or virological features. One (16.7%) out of 6 individuals with HGV acquisition had persistently raised ALT levels and chronic HBsAg positivity. The prevalence of HGV was 14% (41/292) at the end of the observation period. CONCLUSIONS: The prevalence of HGV in our HD population was high; HGV positivity was strongly associated with the location of HD patients among the units; some HD individuals with current HGV infection showed biochemical signs of liver disease without other apparent causes. De novo acquisition of HGV occurred within HD units in the absence of evident parenteral risk factors for HGV other than their presence in the HD environment. A large portion of HGV viremic patients showed non-persistently detectable HGV viremia during the study. Acquisition of HGV was not associated with a rise in ALT activity unlike prior experience with de novo HCV in HD patients. Further investigations are warranted to explain the modes of HGV acquisition and the clinical significance of HGV in th HD population.

Epidemiology of Helicobacter pylori in chronic haemodialysis patients using the new RIBA H. pylori SIA.

BACKGROUND: There are few data concerning the epidemiology of H. pylori in patients on chronic haemodialysis (HD) treatment. These surveys concerned small populations and were made with ELISA technique. However, ELISA-based assays do not differentiate between strains of H. pylori that are associated with ulcers. Recent literature reports that formation of ulcers correlates strongly with the expression of cytotoxin-associated protein (CagA) and vacuolating cytotoxin (VacA) of H. pylori. METHODS: A novel serological test (RIBA H. pylori strip immunoblot assay (SIA)) has been recently introduced, it uses the H. pylori lysate (Lys) along with two additional purified recombinant antigens derived from CagA and VacA of H. pylori. AIM: To study the epidemiology of H. pylori using RIBA H. pylori SIA among chronic HD patients and blood donors as a control group. In addition, the activity of H. pylori was analysed by immunoblot technique in a group of patients with documented ulcers and normal renal function. RESULTS: The prevalence of antibody towards H. pylori among HD patients, blood donors, and patients with documented ulcers was 56% (127/228), 53% (84/158), and 100%, (21/21) respectively; the difference was significant (P=0.0001). The frequency of anti-H. pylori-positive individuals was significantly higher in patients with documented ulcers than HD patients and blood donors, 21/21 (100%) vs 211/386 (55%), P=0.0001. The frequency of antibody to H. pylori in the HD population was significantly associated with race (P= 0.005); no relationship between anti-H. pylori antibody and numerous demographic, biochemical, and clinical features of patients was seen. The frequency of antibodies against virulent strains of H. pylori in HD patients and blood donors with H. pylori was 60% (76/127) and 61% (51/84) respectively; it was 86% (18/21) among individuals with documented ulcers. No significant difference among these three groups occurred. CONCLUSIONS: The frequency of antibody towards H. pylori by RIBA H. pylori SIA was high both in HD patients and blood donors; patients with documented ulcers and normal renal function had significantly higher frequency of anti-H. pylori antibody. The anti-H. pylori antibody rate among HD patients was strongly associated with race. The prevalence of antibody against virulent strains of H. pylori did not change among HD patients and control groups. Studies in large cohorts of HD patients with documented peptic ulcer disease are in progress.

Pulmonary complications in patients with inflammatory bowel disease.

BACKGROUND/AIMS: Between 1996 and 1998 we investigated the occurrence of lung disorders in 82 patients with inflammatory bowel disease (30 patients with ulcerative colitis and 52 patients with Crohn's disease) and a control group of 60 subjects. The aim of our study was to determine the occurrence of pulmonary complications in patients with inflammatory bowel disease, to investigate whether ulcerative colitis or Crohn's disease are connected with a typical lung function disorder, with the inflammatory activity of the disease or if they depend on the presence of other extraintestinal manifestations. METHODOLOGY: We investigated the occurrence of lung disorders in terms of the following parameters: clinical pulmonary symptoms, chest radiography and pulmonary function tests (body plethysmography, pneumotachography, lung transfer capacity for carbon monoxide, and blood gas analysis). RESULTS: Lung function abnormalities were significantly more frequent in patients with inflammatory bowel disease as compared to controls (p<0.001). There was no apparent correlation between these abnormalities and either bowel disease activity or drug administration (sulphasalazine, mesalazine). CONCLUSIONS: Despite the lack of radiological abnormalities, we identified a high incidence of pulmonary function abnormalities (suspicious of interstitial lung disorder) in patients with inflammatory bowel disease; 56.7% of patients with ulcerative colitis and 57.7% of patients with Crohn's disease had reduced lung transfer factor.

Detection of de novo hepatitis C virus infection by polymerase chain reaction in hemodialysis patients.

Patients on chronic hemodialysis (HD) treatment have been identified by serological testing, including second- and third-generation enzyme-linked immunosorbent assay (ELISA), as a high-risk group for hepatitis C virus (HCV) infection. Previous studies have shown that de novo cases of HCV may occur in HD units in the absence of other parenteral exposures, which suggests the spread of HCV between patients. In addition, the reverse-transcription polymerase chain reaction (RT-PCR), which directly detects HCV virus, has identified HCV infection in chronic HD patients who are seronegative. The aim of this study was to determine the incidence of HCV infection detected by RT-PCR technology in a large cohort of chronic HD patients. One hundred and twenty chronic HD patients, HCV-negative by serological assays (second-generation ELISA) and molecular techniques (branched DNA and RT-PCR), were observed for a mean period of 9.5 months. They were tested monthly for serum alanine aminotransferase levels (ALT) and by second-generation ELISA. At the end of the follow-up period, they were again evaluated by branched DNA and RT-PCR testing. HCV RNA was detected in patients' sera by RT followed by PCR using two separate primer sets from the 5'-untranslated region of the HCV genome. Southern blot was performed using a digoxigenin-labeled probe. Two patients who had HCV RNA detectable by RT-PCR at the end of the follow-up period remained branched-DNA-negative. Thus, the incidence of de novo acquisition of HCV infection in the current investigation was 2.1% per year. In 1 patient RT-PCR positivity and anti-HCV ELISA seroconversion occurred. The 2nd patient remained anti-HCV ELISA-negative, although viremic. In both patients, the onset of positivity by RT-PCR was associated with a rise of ALT levels into the 'abnormal range' in our laboratory. In these 2 patients, de novo acquisition of HCV infection was observed in the absence of obvious parenteral risk factors other than their presence in the HD environment. In conclusion, de novo acquisition of HCV infection may be undetected by ELISA and branched-DNA assays. The need to monitor chronic HD patients by serial ALT testing is emphasized. RT-PCR should be incorporated into diagnostic testing for HCV infection in chronic HD patients. RT-PCR technology can identify HCV in HD individuals with raised ALT activity.

Quantitative assessment of HCV load in chronic hemodialysis patients: a cross-sectional survey.

UNLABELLED: Recent evidence has been accumulated showing that chronic hemodialysis (HD) patients have a very high prevalence of antibodies to hepatitis C virus (HCV). In contrast, there is little information addressing the virological characteristics of HCV infection in this population. AIM: To measure HCV viral load and to correlate this with demographic, biochemical, and clinical features of a large cohort of HCV-infected patients on chronic HD. METHODS: 394 chronic HD patients were tested by branched-DNA signal amplification assay, anti-HCV enzyme-linked immunosorbent assay 2.0, and on the basis of the aspartate aminotransferase/alanine aminotransferase (AST/ALT) activity. Multivariate analysis by ordinal logistic regression model was performed: age, gender, race, time on HD, allocation of the patients among the HD units, etiology of end-stage renal disease, HBsAg status, anti-HCV positivity, HCV genotype, and AST/ALT levels were independent factors, and viremic levels of HCV in serum were assumed as dependent variables. RESULTS: 88 (22.3%) patients showed serological and/or virological signs of HCV infection. 59 (15%) out of 394 had detectable HCV RNA in serum, the mean HCV load was 19.4 x 10(5) (95% CI, 6.06 x 10(7) to 6.2 x 10(4)) Eq/ml. According to the criteria suggested by others [J Infect Dis 1994;169:1219-1225], there were 8 (13.5%) individuals with high-titer viremia (>1 x 10(7) Eq/ml) in the subset of viremic patients. A small subset (8/394 or 2%) of individuals was seronegative, but viremic; 29 (7%) out of 394 were seropositive without detectable HCV RNA in serum. Univariate analysis showed that the frequency of anti-HCV positivity was significantly higher in viremic patients as compared with individuals with no detectable HCV viremia: 51/59 (86%) vs. 29/335 (8.6%), p = 0.0001. Serum AST and ALT levels were significantly higher in viremic patients than in individuals with no detectable HCV RNA in serum: 23.8 (95% CI 60.8-9.3) vs. 17.1 (95% CI 50.4-5.8) U/l (p = 0.009) and 14.4 (95% CI 48.9-4.3) vs. 9.8 (95% CI, 37.3- 2. 5) U/l (p = 0.008). Logistic regression analysis showed an association between HCV viremia and anti-HCV positivity (p = 0. 00001) and ALT activity (p = 0.01). CONCLUSIONS: Hepatitis C virus infection is highly prevalent in the HD population; the viral load is relatively low, and it was associated with elevated hepatic enzyme levels and anti-HCV positivity. No other clinical characteristics were associated with HCV RNA levels. Seronegative but viremic patients were also found. Longitudinal studies with long follow-up periods are necessary to evaluate the course of HCV load over time in this population.

Acquisition of hepatitis C virus in hemodialysis patients: a prospective study by branched DNA signal amplification assay.

Serological data indicate that hepatitis C virus (HCV) infection is very common among chronic hemodialysis (HD) patients. Circumstantial evidence suggests that hemodialysis per se is an important risk factor for this infection. We used a novel methodology, the branched DNA (bDNA) signal amplification assay, which is capable of detecting HCV RNA and of quantifying HCV viral load in serum, to prospectively determine the rate of acquisition of HCV infection in 274 anti-HCV-negative patients undergoing HD treatment in four hemodialysis units. Moreover, we used bDNA testing to analyze the dynamics of HCV acquisition among HD patients, a high-risk group for HCV infection with immune compromise conferred from uremia. Two patients were identified with de novo acquisition during 1 year of prospective bDNA testing. Thus, the HCV incidence was 0.73% per year. De novo acquisition of HCV infection was observed in the absence of identifiable parenteral risk factors. Both patients showed the same pattern of HCV acquisition: they underwent an initial viremic phase that was associated with an increase in alanine transaminase (ALT) activity and that preceded the anti-HCV seroconversion. This was followed by HCV RNA clearance and normalization of ALT activity. Anti-HCV positivity occurred 1 and 2 months after the ALT increase in the first and second patients, respectively. Although HCV incidence was low (0.73%), further research is warranted to set the optimal policy for eliminating the risk of nosocomial transmission of HCV in the HD setting. Our findings show the pattern of HCV acquisition in chronic HD patients and emphasize the need to screen the HD population for ALT measurement combined with anti-HCV testing for detecting hepatitis C. HCV RNA testing can identify HCV before seroconversion in individuals with deranged liver function tests. The acquisition of HCV in HD patients without identifiable risk is confirmed.

Automated RIBA hepatitis C virus (HCV) strip immunoblot assay for reproducible HCV diagnosis.

A comparison between the CHIRON RIBA hepatitis C virus (HCV) processor and manual systems was performed by using 88 specimens repeatedly reactive by the second-generation HCV enzyme-linked immunosorbent assay (ELISA) (HCV 2.0 ELISA) and 111 random specimens from volunteer donors. For the second-generation RIBA HCV strip immunoblot assay (SIA) (RIBA HCV 2.0 SIA), test results correlated strongly between the manual and the automated runs (kappa value, 0.937). For the RIBA HCV 3.0 SIA, the correlation of the test results was also high (kappa value, 0.899). Among the specimens with positive results by RIBA HCV 2.0 and 3.0 SIAs, there was a very strong concordance of the test results between the manual and the automated runs with regard to the reactive bands. Nine samples had discordant results between the manual and the automated runs; this was probably attributable to increased variability in antigen scores close to the cutoff values for both tests. Run-to-run and within-run testing by the CHIRON RIBA HCV Processor System showed a very low rate of conflicting values. In conclusion, the CHIRON RIBA HCV Processor System is capable of performing RIBA HCV 2.0 and 3.0 SIAs accurately with minimal operator involvement. In addition, the CHIRON RIBA HCV Processor System shows excellent reproducibility, with the potential for operator-to-operator and site-to-site variability being greatly reduced. Our data indicate that this novel methodology may be very useful for supplemental anti-HCV testing of specimens repeatedly reactive by ELISA in routine clinical assessments and epidemiologic evaluations.

Evaluation of a novel serotyping system for hepatitis C virus: strong correlation with standard genotyping methodologies.

Direct sequencing and analysis of viral genomes are definitive methods for identifying various hepatitis C virus (HCV) genotypes. However, HCV genome sequencing methods are cumbersome and unsuitable for analyzing large numbers of clinical samples. We have developed a convenient, reliable, and reproducible RIBA strip immunoblot assay system for determining HCV serotype. Briefly, the assay consists of an immunoblot strip on which there are five lanes of immobilized serotype-specific HCV peptides from the nonstructural (NS-4) and core regions of the genomes of HCV types 1,2, and 3. HCV serotype is deduced by determining the greatest intensity of reactivity to the NS-4 serotype-specific HCV peptide band in relation to the intensity of the human immunoglobulin G internal control bands on each strip. HCV core peptide reactivity is used only in the absence of NS-4 reactivity. We used this assay to successfully serotype a high percentage of sera from well-documented HCV-infected patients. Our serotyping results correlated 99% with the findings from the standard restriction fragment length polymorphism genotyping methods. Less than 5% of the serum samples were untypeable. For a selected group of alpha interferon-treated patients we observed that the nonresponders (76.2%) and a majority of the responders who relapsed (72.2%) had type 2 HCV infection. A small population (n= 8) of complete responders was split 3:4:1 as type 1, type 2, and type 3, respectively. Our data indicate that this new serotyping assay has the potential to be a highly specific and reliable method for typing of HCV infection in patients.

Magnetic resonance imaging in children receiving quinolones: no evidence of quinolone-induced arthropathy. A multicenter survey.

Twenty-nine children with cystic fibrosis (CF) were investigated for quinolone-induced arthropathy. Magnetic resonance imaging (MRI) was performed in 14/14 children treated with ofloxacin or ciprofloxacin and in 10/15 of those never treated with quinolones. The frequency of pathologic MRI findings, concerning cartilage thickness, careful analysis of the cartilage structure, presence of edema, cartilage-bone borderline and the presence of fluid in joints did not show any difference between both groups. Thus the presence of quinolone-induced arthrotoxicity cannot be confirmed in this study.

Non-A, non-B posttransfusion hepatitis: comparing C and non-C hepatitis.

Using assays to detect antibodies against antigens (C-100, 5-1-1, C-22 and C-33) of the hepatitis C virus, we tested stored sera from 40 patients prospectively identified as having non-A, non-B posttransfusion hepatitis. The 28 patients who demonstrated seroconversion ("documented hepatitis C") had more severe initial disease; all 20 cases of chronic hepatitis occurred in this subgroup. Only 2 of the 12 patients who did not demonstrate such seroconversion even had symptoms. In the group of patients with documented hepatitis C, chronic hepatitis was more commonly seen in men (89%) than in women (40%). The patients in whom antibody to the C-100 antigen developed were younger and had received more blood than had those patients who had hepatitis C diagnosed by demonstration of antibodies to the 5-1-1, C-22 or C-33 antigen (or all three). The proportion of cases of posttransfusion hepatitis that could be associated with antibody sero-conversion decreased around the time that blood banks switched to an all-volunteer system. The hepatitis seen in patients who failed to demonstrate serological evidence of hepatitis C virus exposure was usually clinically unimportant; it may or may not have been due to viral infection.

Restoration of liver function in Gunn rats without immunosuppression using transplanted microencapsulated hepatocytes.

Microencapsulation of cells within synthetic semipermeable membranes is a novel technique that enables the transplantation of cell cultures without the need for immunosuppression. We have previously shown that transplanted isolated encapsulated hepatocytes can provide sufficient short-term metabolic support to improve the survival of animals with galactosamine-induced fulminant hepatic failure. Here we have demonstrated the feasibility of isolated encapsulated hepatocyte transplantation in providing long-term metabolic liver support in Gunn rats. Gunn rats have a congenital inability to conjugate bilirubin and thus exhibit lifelong hyperbilirubinemia. We studied the feasibility of isolated encapsulated hepatocyte transplantation in restoring this specific liver function. Free hepatocytes, isolated from male Wistar rats, were microencapsulated with collagen within a trilayered sodium alginate-poly-L-lysine-sodium alginate membrane using techniques developed in our laboratory. A total of 45 Gunn rats underwent intraperitoneal transplantation with free hepatocytes (5 x 10(7], isolated encapsulated hepatocytes (5 x 10(7], control (empty) microcapsules or no transplant (untreated controls). Serum bilirubin levels were monitored daily for 10 days after transplantation, and subsequent weekly samples were obtained for up to 1 mo. Microcapsules were studied by light and electron microscopy 1 mo after transplantation. During the first week after transplantation, the mean maximum reduction in serum bilirubin levels for the isolated encapsulated hepatocytes, free hepatocytes and control microcapsule transplanted groups was 45.7%, 18.6% and 14.3%, respectively. For up to 1 mo thereafter the mean reduction in serum bilirubin levels in these respective groups was 34.8%, 13.5% and 3.3%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Growth in children living in areas with air pollution]. / Rast detí zijúcich v oblasti so znecisteným ovzdusím.

In a group of 8-12-year-old children from two areas of Bratislava with a different degree of air pollution the authors investigated repeatedly the growth of the children. It was revealed that in boys and girls from the exposed area growth was retarded, as compared with children from a relatively clean area as well as when compared with the Bratislava population. After improvement of the living environment in the exposed area children who grew up in an environment, where the two areas did not differ as to contamination of the atmosphere, achieved the same growth level at the age of 10 years. The results draw attention to the importance of care of the living environment and of attempts to eliminate noxious substances from the atmosphere which is reflected in a better health status and development of the child organism.