Second surgical opinion programs: dead or alive?

BACKGROUND

In the 1970s, second surgical opinion programs were established in an effort to improve medical care and to control health care costs. The cost-effectiveness of these programs has been questioned recently.

STUDY DESIGN

A retrospective review was conducted of elective second-opinion surgical consultations for members of Local 32B-J of the International Service Employees Union for the years 1993-1994. Nonconfirmed consultations were reviewed against claims history data for the subsequent 2 years. Data were analyzed for rates of nonconfirmation by diagnosis and surgical specialty and for cost-effectiveness benefit.

RESULTS

Of the 5,601 second surgical consultations performed, 490 procedures were not confirmed as medically necessary (9%). Claims history survey for these 490 patients for the 2 years following the consultation revealed that no operation was performed in 62%. The highest nonconfirmation rate (41%) was in plastic and reconstructive surgery, followed by gynecology (22%). The cost-benefit ratio for the program was calculated to be 1.34.

CONCLUSIONS

A second surgical opinion program confers both cognitive and psychologic beneficial effects on Joint Trust Fund members and their dependents who are advised to undergo elective operations. Our current second surgical opinion nonconfirmation rate is 9%, with hysterectomy, prostatectomy, and bunionectomy among the procedures most frequently nonconfirmed. The cost-benefit ratio was estimated at 1.34.

Molecular biology of hepatitis D virus: research and potential for application

Superinfection by hepatitis D virus (HDV) leads to acute hepatitis and causes progression to liver cirrhosis in a significant proportion of hepatitis B surface antigen (HBsAg) carriers. Current regimens (interferon) to treat hepatitis D patients has only transient but no lasting effects. New approaches are, therefore, warranted. Recently, several laboratory studies have discovered interesting properties of HDV that may become targets for antiviral chemicals. Viral replication requires the small hepatitis delta antigen (s-HDAg). The s-HDAg is a nuclear phosphoprotein. There is evidence indicating that phosphorylation is important for HDV replication. A second step of replication requires HDV-RNA self-cleavage and self-ligation. Interestingly, one group of antibiotics, the aminoglycosides, exerts strong suppression effects on HDV ribozyme activities. In the following stage of viral assembly, two post-translational modifications, namely isoprenylation of large HDAg and glycosylation of HBsAg are involved. Agents capable of blocking the two modifications should reduce viral production. These four possible targets are reviewed. For prevention, effective vaccines are not yet available. Two novel approaches are discussed. The first demonstrates the immunogenicity of a nucleic acid vaccine in mice. The second approach assembled an empty HDV particle in yeast. Advances on such laboratory investigations may provide new methods for the control of hepatitis D in the future.

Immunoglobulin M antibody response to hepatitis C virus core protein in patients with chronic hepatitis C

We retrospectively assessed the frequency and clinicopathologic and virologic significance of production of immunoglobulin M (IgM) antibody to hepatitis C virus (HCV) core protein in patients with chronic hepatitis C. Sera from 60 patients with chronic hepatitis C were tested for IgM anti-HCVcore (anti-HCc). Twenty of these patients received ribavirin plus interferon-alpha for 24 weeks, and were classified as sustained, transient, or nonresponders on the basis of alanine aminotransferase levels and the presence of HCV RNA at the end of treatment and 24 weeks later. IgM anti-HCc was detected in 21 patients. There was no correlation between the presence of IgM anti-HCc and clinical features such as sex, age, mode of transmission, serum levels of alanine aminotransferase, HCV genotype, serum HCV titer, or histologic findings. Among the patients who received ribavirin plus interferon-alpha, the mean IgM anti-HCc level before therapy was comparable between sustained (n = 10), transient (n = 8), and nonresponders (n = 2). A statistically significant decrease in IgM anti-HCc response during antiviral therapy was observed in the 18 responders who became negative for serum HCV RNA at the end of therapy. These data suggest that IgM anti-HCc is of limited clinical usefulness as a marker of chronic HCV infection. Serial testing for IgM anti-HCc may provide a marker of antiviral response.

Assembly of hepatitis delta virus-like empty particles in yeast

Large delta antigen (L-HDAg) of hepatitis delta virus (HDV) and small-form hepatitis B surface antigen (HBsAg) of helper hepatitis B virus have previously been shown to be the minimum components for the assembly of HDV-like particles in mammalian cells. Extending from this finding, we coexpressed L-HDAg and small HBsAg in Saccharomyces cerevisiae to study their assembly in yeast cells. The assembly of virus particles from L-HDAg and HBsAg in yeast was demonstrated by their coexistence in the same isopycnic fractions and by the coimmunoprecipitation of L-HDAg with HBsAg using an antibody against HBsAg (anti-HBs). Furthermore, after purification by affinity chromatography with anti-HBs, HDV-like particles with size and morphology similar to those derived from mammalian cells could be visualized by electron microscopy. Mice immunized with yeast-derived HDV-like particles simultaneously acquired antibodies against HBsAg and HDAg, indicating that both viral proteins are antigenic. The results indicated that S. cerevisiae could serve as a host for the assembly of HDV-like empty particles. This system may be useful in investigating cellular processes involved in HDV assembly and in producing ample amount of HDV-like particles for structural and immunological studies.

Positive and negative strand of hepatitis C virus RNA sequences in peripheral blood mononuclear cells in patients with chronic hepatitis C: no correlation with viral genotypes 1b, 2a, and 2b

Hepatitis C virus (HCV) has many genotypes which are closely associated with the severity of chronic hepatitis and the response to antiviral therapy. Although HCV is essentially hepatotropic, several lines of evidence suggest that this virus can infect peripheral blood mononuclear cells (PBMC) in most patients with chronic HCV infection. However, the methods used previously to detect negative-strand HCV RNA have been questioned, and the PBMC tropism of different HCV genotypes remains unknown. A stringent method was used to investigate the prevalence of positive- and negative-strand HCV RNA in the PBMC of 106 patients with chronic hepatitis C and to analyze the influence of HCV genotype on the tropism of PBMC. HCV type 1b was the predominant strain in the patients. Positive-strand RNA in PBMC was detected in 83 (78%) and 40% had negative-strand RNA. The demographic and clinical features were comparable among different patients grouped by the replication status of HCV in the plasma and PBMC samples. In addition, there was no significant difference of PBMC tropism between type 1b and non-1b HCV. In summary, HCV does indeed infect actively the PBMC of chronic hepatitis C patients and such infection is not correlated to the pathogenesis of liver cell damage. Moreover, the genotype is not associated specifically with PBMC tropism of HCV.

Effects of apolipoprotein E on dementia and aging in the Shanghai Survey of Dementia

We investigated the status of the apolipoprotein E allele in 538 participants in the incidence phase of the ongoing Shanghai Survey of Dementia, including 103 demented subjects, 72 with mild cognitive impairment and 363 cognitively normal. The apo E epsilon 4 allele was present in 10.2% of control subjects and the allelic frequency did not change between ages 60 to 96 years. The apo E epsilon 4 allelic frequency was increased both in those wiht Alzheimer's disease (AD) (25.4%) and those with vascular dementia (VaD) (22.2%), but not in those with other dementing illnesses or the cognitively impaired. All of the subjects homozygous for apo E epsilon 4 were demented, three were diagnosed as having AD, and three met NINDS/AIREN criteria for VaD. The increased apo E epsilon 4 allelic frequency in clinically diagnosed VaD patients suggests that some of the infarcts are secondary to congophilic angiopathy. The adjusted odds ratio of developing AD in this community-derived study for persons with at least one apo E epsilon 4 allele was 4.1 (95% CI: 2.2, 7.7). Thus, the apo E epsilon 4 risk of developing AD in this Chinese cohort is similar to that in western community studies.

GB virus-C/hepatitis G virus infection in prostitutes: possible role of sexual transmission

The modes of transmission of GB virus-C/hepatitis G virus (GBV-C/HGV) other than by blood transfusion are largely unknown. The prevalence of GBV-C/HGV viremia and the associated risk factors in 145 female prostitutes were examined. The seroprevalence of hepatitis B surface antigen (HBsAg), antibodies to hepatitis C virus (anti-HCV), and GBV-C/HGV RNA were 14%, 18%, and 11%, respectively. The demographic characteristics were similar between subjects with and without HBsAg. In contrast, those with HCV or GBV-C/HGV infection had practised longer as prostitutes and received blood transfusion more frequently. Moreover, the prevalence of GBV-C/HGV RNA and anti-HCV tended to increase in parallel with the duration of prostitution. These results suggest that like HCV, sexual transmission of GBV-C/HGV occurs and the risk increased with prolonged duration of exposure. The transmission efficiency between GBV-C/HGV and HCV appears to be similar.

Amplification of GB virus-C/hepatitis G virus RNA with primers from different regions of the viral genome

GB virus-C/hepatitis G virus (GBV-C/HGV) is a newly identified RNA virus. The aim of the study was to compare three primer pairs from the 5' untranslated region (5'UTR), envelope region 2 (E 2) and nonstructural region 3 (NS 3) of GBV-C/HGV genome for their ability to detect GBV-C/HGV RNA by polymerase chain reaction (PCR) assays. By using PCR with primers from different regions of the viral genome, serum GBV-C/HGV RNA was assayed in 200 at-risk individuals. The sensitivity of this assay was assessed by a titration experiment, and nucleotide sequences of the amplified products were determined directly. Of 200 serum samples, 43 (21.5%) were positive for GBV-C/HGV RNA with at least one of the primer pairs. The positive rates by 5'UTR, NS 3, and E 2 primers were 100%, 98%, and 84%, respectively, and the sensitivity of PCR assays using 5'UTR primers was 10 to 100 times more likely to detect GBV-C/HGV RNA than that of NS 3 and E 2 primers. The average homology of amplified targets to the prototype HGV genome was 89%, 80%, and 85% and the similarity between each amplified target was up to 100%, 90%, and 92% in the 5'UTR, E 2, and NS 3 regions, respectively. Therefore, the 5'UTR of GBV-C/HGV genome is highly conserved and primers deduced from this region can provideva sensitive and specific PCR assay for GBV-C/HGV RNA.

Benign recurrent intrahepatic cholestasis

Benign recurrent intrahepatic cholestasis is a rare disorder of unknown etiology and has not yet been reported in Taiwan. We report a case with a typical clinical course. A 17-year-old Taiwanese boy had three episodes of pruritus and jaundice from February 1993 to July 1995, each lasting 3 to 4 months. Jaundice spontaneously subsided and he was symptom-free during periods of remission. A fourth episode of pruritus began in July 1995, with jaundice developing later and lasting for 3 months. Laboratory tests revealed direct hyperbilirubinemia. Endoscopic retrograde cholangiopancreatography showed normal intra- and extrahepatic biliary trees. Light microscopy of a liver biopsy sample revealed hepatocellular and canalicular cholestasis with bile retention in the Kupffer cells. Benign recurrent intrahepatic cholestasis was diagnosed after exclusion of other possible causes of jaundice. The patient made an uneventful recovery.

Evolution of hepatitis C virus quasispecies in mothers and infants infected through mother-to-infant transmission

BACKGROUND/AIMS

Two mother-infant pairs (Pair H and P) were studied to determine the evolution of hepatitis C virus (HCV) quasispecies.

METHODS

Eight clones of the hypervariable region of HCV cDNA from the infants' sera sampled at the age of 3 months, 1, 2, and 3 years and the time-corresponding maternal sample were also sequenced. The sequences were analyzed by the nucleotide diversity, substitution rate, and phylogenetic studies.

RESULTS

HCV quasispecies of the infants were more homogeneous than those of their mothers, particularly at the age of 3 months (nucleotide diversity, pi = 0.18 x 10(-2)/site in infant H, and 0.22 x 10(-2)/site in infant P). The nucleotide substitution rate in infants also increased as they aged, from 1.2 x 10(-2) to 4.46 x 10(-2)/site/year in infant H, and from 0.21 x 10(-2) to 4.88 x 10(-2)/site/year in infant P respectively. The nucleotide sequence differences between infants and mothers increased from 2.63 x 10(-2) to 9.06 x 10(-2)/site in Pair H, and from 1.85 x 10(-2) to 5.33 x 10(-2)/site in Pair P within 3 years. Phylogenetic studies suggest the infants' initial quasispecies were closely related to their mothers', while they evolved differently. HCV RNA titer was stable during follow-up and the infants' titer was similar to their mothers'. The fluctuations in titer did not correlate with nucleotide diversity.

CONCLUSIONS

HCV quasispecies evolved differently in each individual, even though they were genetically linked. The sequence in infants was not a complex as in their mothers.

Synergistic transactivation of HNF-1alpha, HNF-3, and NF-I contributes to the activation of the liver-specific protein C gene

We have previously characterized the functional cis elements of the protein C promoter. One hepatocyte nuclear factor-1 (HNF-1) site, three HNF-3 sites, and at least two NF-I sites have been identified within the 140-bp basal transcriptional unit of this promoter. Here we present evidence that either HNF-1alpha or HNF-3 can cooperate with each other in binding to their cis elements. The results from the co-transfection assays in HeLa cells showed a novel synergistic transactivation between HNF-1alpha and HNF-3. Our data further indicate that the unique overlapping of the HNF-3 sites, the specific spatial relationship of the sites, and the co-activator C/EBP all contributed to the synergistic interaction. Although NF-I itself has a weak transactivating effect, it apparently coordinates the transactivation complex formation. NF-I can synergistically enhance the transactivation of HNF-1alpha or HNF-3. Taken together, the combinatorial interplay of HNF-1alpha, HNF-3, and NF-I make a significant contribution to the activation of the liver-specific protein C gene.

GB virus-C/hepatitis G virus infection in an area endemic for viral hepatitis, chronic liver disease, and liver cancer

BACKGROUND & AIMS

GB virus-C/hepatitis G virus (GBV-C/HGV) is a newly identified flavivirus, and little is known about its clinical significance. GBV-C/HGV was investigated in different populations, and its coinfection was investigated in patients with liver disease in Taiwan where hepatitis B and C are endemic.

METHODS

Viral RNA was studied in 70 high-risk individuals, 20 patients with chronic non-B, non-C hepatitis, 13 with non-A-E fulminant hepatitis, 100 with asymptomatic hepatitis B surface antigen carriage, 120 with hepatitis B surface antigen-positive chronic liver disease and hepatocellular carcinoma, 100 patients with chronic hepatitis C, and 100 healthy adults.

RESULTS

GBV-C/HGV infection was more frequent in high-risk groups (15%-30%) and hepatitis C virus carriers (10%) than in healthy adults (1%) and hepatitis B virus carriers (3.2%). Eighty-three percent of those infected had undergone blood transfusions previously. The prevalence in hepatitis B virus carriers increased with the severity of liver disease, being 1% in asymptomatic carriers and 10% in hepatocellular carcinoma. In chronic hepatitis C, clinical and virological data were comparable between those with and without coinfection.

CONCLUSIONS

In Taiwan, GBV-C/HGV infection is common in high-risk groups, and its coinfection seems to not aggravate the course of chronic hepatitis B or C.

Superinfection by homotypic virus in hepatitis C virus carriers: studies on patients with post-transfusion hepatitis

Although heterotypic superinfection and mixed infections of hepatitis C virus (HCV) may be possible for hepatitis flares in chronic hepatitis C, the possibility of homotypic HCV superinfection in HCV carriers with post-transfusion hepatitis has not been explored. Six HCV carriers with post-transfusion non-A, non-B hepatitis found in a prospective study of post-transfusion hepatitis were included. Serum samples before transfusion and during hepatitis were selected to determine genotypes of HCV and nucleotide sequences of the hypervariable region (HVR). The genotypes identified before and after transfusion were concordant in all. There were four with type 1b and one each with type 2a and type 2b. Amplified nucleotide sequences of the HVR before transfusion and during hepatitis were compared in four patients, and a > 95% homology was observed in three, suggesting persistence of original viruses. In contrast, only a 51% homogeneity was seen in a given patient, suggesting a homotypic HCV superinfection. Phylogenetic tree analysis validated further these findings. This study implies that HCV carriers can be reinfected by homotypic HCV, and this may contribute to hepatitis flares in chronic hepatitis C. These findings also confirm a weak or inadequate protective immunity in HCV infection and justify protection from reinfection of HCV of patients with chronic hepatitis C.

Serum hepatitis C virus titers in the progression of type C chronic liver disease. With special emphasis on patients with type 1b infection

The correlation of serum hepatitis C virus (HCV) titers to the progression of type C chronic liver disease remains controversial. We have investigated the relationship between serum HCV titers and different histological stages of chronic liver disease, including chronic persistent hepatitis (CPH), chronic active hepatitis and/or liver cirrhosis (CAH/LC), and hepatocellular carcinoma (HCC) in 94 well-characterized Taiwanese patients. The mean age of patients in the HCC group was significantly older than those in the CPH and CAH/LC groups, whereas those in the CAH/LC group had the highest mean serum alanine aminotransferase level among the three groups. The prevalence of HCV type 1b increased with the progression of histological severity, and the mean serum titer of the HCC group was significantly higher than that of CPH group. The difference of virus titers between the HCC group and those of the other two groups became more significant when only type 1b virus-infected patients were analyzed. In conclusion, elevated serum HCV titers are more frequently observed among Taiwanese patients with advanced type C chronic liver disease, an association not related to the high prevalence of HCV type 1b infection in such patients.

Long-term efficacy of ribavirin plus interferon alfa in the treatment of chronic hepatitis C

BACKGROUND & AIMS

Sustained response to interferon treatment for chronic hepatitis C is unsatisfactory. This study examined whether combining interferon alfa with ribavirin induces a better sustained efficacy than interferon alone in the treatment of chronic hepatitis C.

METHODS

Sixty noncirrhotic patients with chronic hepatitis C were randomly assigned to three groups. Group 1 received 1200 mg oral ribavirin daily plus 3 million units of recombinant interferon alfa 2a thrice weekly for 24 weeks, group 2 received the same dose of interferon alfa 2a alone for 24 weeks, and group 3 received no treatment. The patients were then followed up for an additional 96 weeks.

RESULTS

At the end of treatment, a complete response (normal serum alanine aminotransferase level and undetectable serum hepatitis C virus RNA) was achieved in 16 of the 21 patients in group 1 (76%), as compared with 6 of 19 in group 2 (32%) and none in group 3. At 96 weeks after the end of treatment, patients in group 1 sustained a higher complete response rate than patients in group 2 (43% vs. 6%).

CONCLUSIONS

Combined treatment with ribavirin and interferon alfa 2a for 24 weeks is more effective than interferon alfa 2a alone for the treatment of chronic hepatitis C. The biochemical and virological responses were sustained in about one half of the treated patients for at least 2 years after cessation of the therapy.

Characterization of human protein C gene promoter: insights from natural human mutants

Human protein C is a liver-produced plasma anticoagulant. Four heterozygous point mutations located in the promoter region have been identified in families with type I protein C deficiency and recurrent venous thrombosis. However, detailed analysis of regulatory elements and their interacting factors remains to be undertaken. This report presents results of biochemical and functional characterizations of several cis-elements located in the 5'-upstream regulatory region and the trans-acting factors that interact with them. A cloned DNA fragment from nucleotides (nt) -418 to +45 could confer tissue specificity, whereas nt -88 to +45 was sufficient for basal promoter activity of protein C gene. Five cis-elements corresponding to HNF-1, HNF-3, and NF-I/CTF binding sites have been identified. Four heterozygous mutations have been shown to disrupt HNF-3 [mutants of A(-32)G and T(-27)A] and HNF-1 [T(-14)C and C(-10)T] binding. Mutation in the NF-I-binding site also significantly impairs the promoter activity. Viewed as a whole, these results indicate that HNF-1, HNF-3, and NF-I/CTF play critical roles in transcriptional regulation of the protein C gene.

Transmission of hepatitis C virus between spouses: the important role of exposure duration

OBJECTIVES

Although interspousal transmission of hepatitis C virus (HCV) has been studied, the factors responsible for it remain unclear.

METHODS

To investigate the transmission of HCV between spouses and the related risk factors, 100 anti-HCV-positive index patients and their spouses were studied.

RESULTS

Overall, anti-HCV was detected in 17 (17%) spouses, 15 of whom were also positive for HCV RNA, and 11 couples were infected with the same genotype. The anti-HCV-positive rate was higher in spouses married longer than 20 yr compared with those married less than 20 yr (22 vs 6%, p < 0.05), and the infection was correlated with the duration of their actual exposure to the index patients but not with serum HCV titers. The infected couples had more frequent sexual contacts and more commonly shared tooth-brushes than those with uninfected spouses.

CONCLUSION

Spouses of patients with chronic hepatitis C have a higher risk of acquiring HCV that increases with longer marriage and duration of exposure, and they should be educated about how to avoid contracting HCV infection from their spouses.

A prospective study of transfusion-transmitted GB virus C infection: similar frequency but different clinical presentation compared with hepatitis C virus

To study the incidence and outcome of GB virus C (GBV-C) infection in blood recipients. Serum samples collected in a prospective study were examined for GBV-C RNA by a nested polymerase chain reaction assay. Among the 400 adults who underwent cardiac surgery, 40 were positive for GBV-C RNA, including six whose pretransfusion sera were already positive and seven coinfected with hepatitis C virus (HCV) during transfusion. The risk of transmission was estimated to be approximately 0.46% per donor. GBV-C viremia was detectable 1 week after transfusion and could persist for 8 years. However, no evident symptoms or signs were noted in the 25 patients infected by GBV-C alone, and the average peak serum alanine aminotransferase activity was 31 IU/L only (range, 12 to 123), with persistently normal levels in 20 patients. In the seven patients coinfected with HCV, the clinical courses of posttransfusion hepatitis were similar to those infected by HCV alone. In eight patients with posttransfusion non-A approximately E hepatitis, only one was positive for GBV-C RNA. Sixty samples were chosen to test hepatitis G virus (HGV) sequences, 26 of the 30 GBV-C positives were positive for HGV RNA in contrast to none of the 30 GBV-C negative samples. In conclusion, GBV-C can be transmitted by transfusion in approximately 9% of patients who underwent cardiac surgery. Nevertheless, this virus does not seem to cause classic hepatitis in most instances.

Subtyping of human T-lymphotropic virus type I by amplification of long terminal repeat sequences and restriction fragment length polymorphism analysis in carriers with multiple transfusions

Five major subtypes of human T-lymphotropic virus type I (HTLV-I) have been proposed: cosmopolitan, Japanese, West African, Central African, and Melanesian. Based on nucleotide variations specific to particular subtypes, it was possible to genotype HTLV-I rapidly by restriction fragment length polymorphism (RFLP) studies following polymerase chain reaction (PCR). In this study, the restriction patterns of two LTR fragments were analyzed using eight restriction endonucleases (AvaI, Eco57I, BsoFI, NdeI, SacI, DraI, MaeII, and MaeIII). Genotyping of HTLV-I was done in nine patients with adult T-cell leukemia or HTLV-I-associated myelopathy/tropical spastic paraparesis, in three prostitutes, and in 19 carriers with multiple transfusion in Taiwan. The subtyping results of RFLP studies using these eight restriction endonucleases were in accordance with those of phylogenetic analysis. A substitution of G by A at nucleotide position 503, which creates the DraI site but suppresses the SacI site, was found not only in the Japanese subtype but also in a minority of the cosmopolitan subtype. A mutation near the position of subtype-specific nucleotide variations might suppress the restriction site and lead to unexpected restriction patterns. Amplification of more than one proviral fragment and RFLP studies with a group of appropriate restriction endonucleases may provide rapid and accurate genotyping of HTLV-I. More carriers are required to evaluate the possibility of mixed infection with different HTLV-I subtypes.

Casein kinase II and protein kinase C modulate hepatitis delta virus RNA replication but not empty viral particle assembly

Hepatitis delta virus (HDV) contains two virus-specific delta antigens (HDAgs), large and small forms, which are identical in sequence except that the large one contains 19 extra amino acids at the C terminus. HDAgs are nuclear phosphoproteins with distinct biological functions; the small form activates HDV RNA replication, whereas the large form suppresses this process but is required for viral particle assembly. In this study, we have characterized the phosphorylative property of HDAg in a human hepatoma cell line (HuH-7) and examined the role of phosphorylation in HDAg function. As demonstrated by in vivo labeling and kinase inhibitor experiments, the phosphorylation levels of both HDAgs were diminished by the inhibitor of casein kinase II (CKII). Nevertheless, phosphorylation of only the small form could be markedly reduced by the protein kinase C (PKC) inhibitor, suggesting different phosphorylation properties between the two HDAgs. When these two kinase inhibitors were added separately to the transient-expression system, HDV RNA replication was profoundly suppressed. In contrast, the inhibitors did not affect the assembly of empty HDAg particle from HDAgs and hepatitis B virus surface antigen. To further examine the role of phosphorylation in HDAg function, two conservative CKII recognition sites at Ser-2 and Ser-123 of both HDAgs and one potential PKC recognition site at Ser-210 of the large HDAg were altered to alanine by site-directed mutagenesis. Transfection experiments indicated that mutation at Ser-2, but not Ser-123, significantly impaired the activity of the small HDAg in assisting HDV RNA replication. This property is in accordance with our observation that Ser-2, not Ser-123, was the predominant CKII phosphorylation site in the small HDAg. Our studies also excluded the possibility that the phosphorylation of Ser-2, Ser-123, or Ser-210, had roles in the trans-suppression activity of the large HDAg, in the assembly of empty virus-like HDAg particle, and in the nuclear transport of HDAgs. In conclusion, our results indicate that both CKII and PKC positively modulate HDV RNA replication but not the assembly of empty HDAg particle. The role of CKII in HDV replication may at least in part be accounted for by the phosphorylation of Ser-2 in the small HDAg. The effect of PKC on HDV RNA replication is, however, not to mediate the phosphorylation of the conservative Ser-210 in the large HDAg but rather to act on as-yet-unidentified Ser or Thr residues in the small HDAg or cellular factors. These findings provide the first insight into the roles of phosphorylation of the two HDAgs in the HDV replication cycle.

Rapid hepatic failure associated with a contracted liver mimicking cirrhosis in a case of nasopharyngeal carcinoma with liver metastasis

A 46-year-old women had an undifferentiated nonkeratinizing nasopharyngeal carcinoma, locally controlled by radiotherapy. Initially, she had normal liver function tests and normal hepatic ultrasonography. Seven months later, she experienced a rapidly progressive hepatic failure manifested by the development of ascites, elevation of serum bilirubin level, and prolongation of prothrombin time. Imaging studies showed a contracted liver and serum biochemical tests were compatible with chronic liver disease, except for an increase of alkaline phosphatase and gamma-glutamyl transpeptidase levels. An endoscopic retrograde cholangiogram ws compatible with changes of sclerosing cholangitis. The patient died of hepatic decompensation within two months. A liver necropsy disclosed diffuse infiltration of carcinoma cells into the hepatic sinusoids and obliterative angio-invasion of the tumor cells with massive fibrotic stroma replacing almost all hepatocytes. In situ hybridization demonstrated expression of Epstein-Barr virus transcripts EBER1 in the tumor cells and proved a metastatic nasopharyngeal carcinoma. The contracted liver is likely to be explained by the tumor-associated desmoplastic change and the obliterative angio-invasion of the tumor. It is important to be aware that, although rare, such an unusual pattern of liver metastasis may mimick cirrhosis clinically and cause rapid hepatic failure in patients with nasopharyngeal carcinoma.

Phylogenetic analysis of GB virus C: comparison of isolates from Africa, North America, and Taiwan

A group of flavi-like GB viruses (GBV-A, -B, and -C) has been discovered and partially characterized. Only GBV-C is found in humans. Nucleotide sequences of the putative helicase gene of the GBV-C genome were determined in 21 Taiwanese patients and compared with isolates from Africa and North America by phylogenetic analysis. The average similarities of Taiwanese isolates to those from West Africa, East Africa, Canada, and United States were 83%, 85%, 78%, and 82%, respectively. Phylogenetic analysis of the NS3 region showed that 81% of the Taiwanese isolates were more closely related to the East African isolate. GBV-C isolates from Taiwan could be classified into at least 3 groups. These data suggest that GBV-C isolates cloned from different geographic areas have genetic heterogeneity.

Identification of humoral antigenic determinants in the hepatitis C virus NS3 protein

Immunoblot analysis on serum samples from 90 patients with chronic hepatitis C virus infection revealed four putative immunogenic regions within the NS3 protein of the virus: E (around aa 1250/ 1251), A (within aa 1250-1334), A/B (around aa 1323 and 1334), and B/C (around aa 1407 and 1412). Among them, region E was most immunodominant, and region A was recognized much less frequently by patients with cirrhosis than by those with chronic hepatitis (10% vs. 46%, chi 2 = 12.05, P < .01). The results suggest that region A might be a potential prognostic marker to differentiate chronic hepatitis from cirrhosis.

Absence of extensive genetic heterogeneity of hepatitis C virus in antibody-negative chronic hepatitis C

Hepatitis C virus (HCV) carriers usually have antibodies to HCV; however, there are viremic individuals without these antibodies. To investigate whether variations of the viral genome are responsible for this discrepancy, the nucleotide and deduced amino acid sequences of HCV capsid and nonstructural regions obtained from 15 viremic patients were examined. These 15 patients were infected with type 1b HCV, and 10 did not have antibody to HCV assayed with second-generation tests. The nucleotide homology of the 5 seropositive and 10 seronegative patients with the HCV prototype sequence were 91.6% and 91.9%, respectively, in the capsid region. There was no apparent difference in the deduced amino acid sequences between the two groups of patients studied (94% vs. 95%). The nucleotide and amino acid sequences of a part of the nonstructural region 3 also showed similar results. These findings suggest that absence of antibodies against both capsid and nonstructural peptides in HCV carriers is not caused by genetic heterogeneity of the viral epitopes.

H-2Ld-alloreactive T cell hybridomas utilize diverse V alpha and V beta T cell receptor chains

We have sequenced the TCRs from Ld-specific alloreactive T cell hybridomas, whose reactivities we have found to be quite representative of those of a primary dm2 anti-BALB/cJ mixed lymphocyte reaction. We find V beta 6, V beta 7, V beta 8 and V beta 10 gene segments. V alpha usage is diverse, although closely related to that from peptide-specific Ld-restricted CTLs. V alpha-V beta selection provides evidence of preferential pairing. Amino acid frequency analysis shows that the alpha CDR2 region is rich in charged amino acids, in contrast to the beta CDR2 region. Our data suggests the beta chain may be more immunoglobulin-like than the alpha chain, and that charge complementarity may be important in TCR-MHC interactions. We do not consider our results to be contradictory to those previously reported but rather they may represent an early, more diverse response.

N-linked glycosylation of hepatitis B surface antigens is involved but not essential in the assembly of hepatitis delta virus

Hepatitis delta virus (HDV) is a defective virus requiring the hepatitis B virus (HBV) to provide hepatitis B surface antigens as the envelope protein. The hepatitis B surface antigens are posttranslationally modified by N-linked glycosylation, and its significance in HDV assembly was investigated with a cotransfection system using human hepatoma cell line Huh-7. After the N-linked glycosylation of HBsAg was blocked by tunicamycin treatment, the packaging of HDV in the culture system could be suppressed to a level as low as 5-10% of the untreated control. The extent of inhibition correlated with the increased concentrations of tunicamycin. In contrast, the loss of HBsAg glycosylation did not affect the efficiency of assembly of HBV particles. When the N-linked glycosylation site of small HBsAg at amino acid 146 was mutated from asparagine to glutamine, the mutant HBsAg packaged only a modest amount of HDV particles. The quantity and kinetics of formation of HDV particles in culture system were reduced by the depletion of HBsAg glycosylation. Therefore HDV, similar to influenza and vesicular stomatitis viruses, depends on glycosylation of the envelope proteins as a signal for envelope protein maturation and for virion formation.

Serotypes, genotypes and levels of hepatitis C viremia in pregnant women in Taiwan

The correlation between a new serotyping method for grouping different genotypes of hepatitis C virus (HCV) and those identified by a polymerase chain reaction (PCR) assay with type-specific primers was investigated in 3,400 pregnant women. The correlation between HCV genotypes and serum HCV levels in HCV-positive pregnant women was studied as well. The new serologic assay used an enzyme-linked immunosorbent assay (ELISA) based on highly group-specific recombinant peptides (C14-1 and C14-2) within the NS4 region and detected group-specific antibodies against different HCV genotypes. Serum HCV levels were assayed by a competitive PCR method. In all, 43 pregnant women were found to be positive for HCV antibodies by the second-generation ELISA method and were positive for HCV-RNA by PCR with primers from the 5' untranslated region. All 43 had defined genotypes: 28 (65%) with HCV 1b, 11 (26%) HCV 2a, 3 (7%) HCV 2b and 1 (2%) HCV 1b + 2a. In 40 (93%) of the 43 viremic pregnant women, the results of serotyping by ELISA showed complete agreement with those determined by PCR genotyping, and none of the women showed a group different from that of the HCV genotype. In addition, serum levels of HCV 1b were significantly higher than those of HCV 2a. The results show that this new serotyping assay is highly sensitive and specific for the determination of HCV genotypes and that serum HCV levels in pregnant women with genotype 1b are higher than those with genotype 2a.

Serotyping of hepatitis C virus in chronic type C hepatitis in Taiwan: correlation with genotypes

To evaluate the usefulness of a new serologic assay to group hepatitis C virus (HCV), genotypes identified by this serotyping method were compared to those identified by a polymerase chain reaction (PCR) assay with type-specific primers in 71 Taiwanese patients with chronic type C hepatitis. The group-specific antibodies against different HCV genotypes were detected by using an enzyme-linked immunosorbent assay (ELISA) based on group-specific recombinant peptides (C14-1 and C14-2) within the NS4 region. Among 71 patients positive for current second-generation HCV antibodies, HCV RNA was detected in 55 patients by PCR with primers from the 5' untranslating region, and in 52 by genotype-specific PCR. In 49 (89%) of 55 viremic patients, the results of serotyping by ELISA showed complete agreement with those determined by PCR genotyping, and none of the patients showed a group opposite to that of HCV genotype. The positive rate of group-specific antibodies (69/71;97%) was even better than that of the PCR (55/71;78%). We conclude that this new serotyping assay is highly sensitive and specific for the determination of HCV genotypes, and will be useful in future epidemiologic studies, as well for clinical application.

Clinical significance of serum hepatitis C virus titers in patients with chronic type C hepatitis

OBJECTIVES

To investigate the relationship between serum hepatitis C virus (HCV) titers and clinicopathological characteristics of chronic type C hepatitis.

METHODS

Serum HCV cDNA concentrations were determined by a competitive polymerase chain reaction assay in 60 Taiwanese patients with chronic type C hepatitis.

RESULTS

The concentration of serum HCV cDNA ranged between 10(2) and 10(8) copies/mL. The titers of serum HCV (logarithmic transformed copies of HCV cDNA/mL serum) were not significantly correlated with clinicopathological characteristics with respect to either sex of the patients, source of infection, higher serum ALT level (>150 IU/L) or histological severity. In contrast, serum HCV titers were significantly higher in patients with age above 50 yr and with type 1b HCV infection. Moreover, the influence of advancing age on serum HCV titer was genotype-independent by multivariate analysis.

CONCLUSIONS

These results suggest that advancing age and genotype are both important determinants of HCV viremia and that the pathogenesis of HCV infection might not be caused by direct cytotoxicity of the virus.

Hepatitis C viral infection in thalassemic children: clinical and molecular studies

To determine and correlate the liver function profile, hepatitis C virus (HCV) genome, anti-HCV, genotypes, quantitation, and nucleotide sequence variability in polytransfused thalassemic children, 61 such children were studied prospectively for 4 y. Twenty-six had HCV infection. The average age, number of transfusions, and alanine aminotransferase (ALT) levels of the HCV-infected group were higher than those of the 35 children without HCV infection. None was infected after the initiation of anti-HCV screening in donor blood. Liver biopsies were performed in six HCV-infected and eight HCV-noninfected thalassemic children, and portal fibrosis was found more frequently in the HCV-infected group. Quantitation of HCV RNA was done by the competitive polymerase chain reaction method, and the titer was about 1 x 10(6) to 5 x 10(8) copies/mL. The titer did not change significantly over the 4-y follow-up period and did not correlate with ALT levels. Nineteen HCV-infected patients were genotyped; 15 were Okamoto/Simmonds type II/1b, two were type III/2a, and two were type IV/2b. The hypervariable region of the HCV genome (E2/NS1) was cloned and sequenced in two serum samples from one patient collected at a 2-y interval, as the ALT levels decreased. The variation rate was estimated to be 1.2-1.7 x 10(-2)/nucleotide/y. The results showed that, in polytransfused thalassemic children, 43% (26/61) contracted HCV. We conclude that HCV infection may cause elevated ALT levels and portal fibrosis of the liver, whereas the viral titer and genotypes do not parallel ALT levels.

Envelope gene sequences of human T-lymphotropic virus type 1 in Taiwan

Three major types of HTLV-1 had been proposed, the Melanesian type, the Zairian type, and the cosmopolitan type, which was further divided into subtypes A, B and C, according to the phylogenetic tree constructed from LTR sequences of current HTLV-isolates. In this study, the envelope gene sequences of HTLV-1 from 9 Taiwanese were analyzed. Based on the phylogenetic tree constructed by unweighted pair group method and the sequence homology analysis by GCG computer programs, the envelope gene sequences of HTLV-1 proviruses from these 9 Taiwanese belonged to subtype A or subtype B of the cosmopolitan type and were closely related to HTLV-1 from Japan. Twelve subtype-specific nucleotide variations were deduced from the comparison of complete or partial envelope gene sequences of 16 HTLV-1 isolates of known subtypes as well as those of 9 Taiwanese. These data provided the basis for subtyping the cosmopolitan type of HTLV-1 by amplification of envelope gene sequences and restriction fragment length polymorphism studies. A more extensive survey based upon this proposal was warranted.

Allelic loss on chromosomes 4q and 16q in hepatocellular carcinoma: association with elevated alpha-fetoprotein production

BACKGROUND & AIMS

In human hepatocellular carcinoma, restriction fragment length polymorphism analysis has shown frequent allelic loss on chromosomes 4q and 16q. To better define the commonly affected region for further positional cloning of the putative tumor-suppressor genes contained in these two chromosome arms, microsatellite polymorphism analysis was conducted to analyze extensively the allelic loss on both chromosome loci.

METHODS

DNA from 42 pairs of large hepatocellular carcinoma (> 5 cm) and corresponding nonneoplastic liver tissues were prepared. Allelic loss on chromosome 4q and 16q was investigated by 13 or 12 sets of microsatellite polymorphic markers.

RESULTS

The frequency of allelic loss on chromosome 16q was 70%, and the common region was mapped to 16q22-23. An even higher frequency (77%) was found on chromosome 4q with the common region mapped to 4q12-23. The allelic loss of chromosome 4q was significantly associated with hepatocellular carcinoma of elevated serum alpha-fetoprotein but not with those of normal level (91% vs. 30%; Fisher's Exact Test, two-tailed P = 1.12 x 10(-4)).

CONCLUSIONS

The results form the basis for further positional cloning of putative tumor-suppressor genes on chromosome 4q and 16q. Moreover, the one on chromosome 4q might shed light on the mechanism of alpha-fetoprotein expression in hepatocellular carcinoma.

Chronic hepatitis C without anti-hepatitis C antibodies by second-generation assay. A clinicopathologic study and demonstration of the usefulness of a third-generation assay

To study the clinicopathologic features of hepatitis C viremic patients negative for hepatitis C antibodies (anti-HCV) by current second-generation assay, we categorized 139 consecutive histologically verified patients with chronic non-A, non-B hepatitis into three groups: 121 (87%) were positive for second-generation anti-HCV (group A); 10 (7%) were negative for second-generation anti-HCV but positive for HCV RNA (group B); and 8 (6%) were negative for both antibodies and viremia (group C). Six (60%) of group B patients could be, further detected by a new third-generation assay, but none of group C patients was third-generation anti-HCV-positive. The demographic features, mean peak serum alanine aminotransferase levels, HCV genotype distribution, and histologic changes were comparable among the three groups. The study indicates that most patients with chronic hepatitis C in Taiwan could be identified by current second-generation assay, and viremic but antibody seronegative patients were clinicopathologically similar to the seropositives. Most patients of the latter group could be diagnosed by a third-generation assay, indicating the usefulness of this assay.

Prevalence, genotypes and antibody titer of hepatitis C virus in pregnant women in Taiwan

OBJECTIVES

To investigate the prevalence and genotypes of hepatitis C virus (HCV) in pregnant women in Taiwan, as well as to examine whether any correlation occurs between HCV genotype and anti-HCV titer.

METHODS

Forty-three pregnant women with positive anti-HCV and HCV-RNA were selected among 3,400 cases screened from January 1992 to March 1994. Each blood specimen was assayed for HCV genotypes by PCR method to detect HCV I, II, III and IV. Anti-HCV titer was determined by a second-generation EIA kit with serial dilutions.

RESULTS

Twenty-eight cases (65%) belonged to HCV II, 11 (26%) HCV III, 3 (7%) HCV IV and 1 (2%) HCV II+III. Besides, the anti-HCV titers in HCV II and HCV III groups were similar, ranging from 8x to 40,000x and revealing no statistical significance (p = 0.75).

CONCLUSIONS

Our data have verified that the prevalence rate of HCV infection in pregnant women is around 1.3% and no significant difference of anti-HCV titer occurs between HCV II and HCV III pregnant women.

Myelin proteolipid protein-induced Th1 and Th2 clones express TCR with similar fine specificity for peptide and CDR3 homology despite diverse V beta usage

Myelin-specific T-helper (Th) cells which induce encephalomyelitis belong to the inflammatory Th1 subset. Th2 cells recognizing similar epitopes potentially represent specific inhibitors of encephalitogenic Th1 cells. Since the differential stimulation of antigen-specific Th2 cells may be important in the regulation of autoimmune inflammatory disorders, we have examined the fine specificity of a Th1 and a Th2 clone, induced by immunization of SJL mice with native proteolipid protein (PLP) and specific for the PLP 139-151 sequence. Stimulation of the clones by synthetic peptides containing single alanine substitutions demonstrated that L141, W144, H147, and P148 represent critical residues. Surprisingly, this pattern was identical for both subsets. Competition studies indicated indirectly that L141 and P148 may be MHC-binding residues, whereas W144 and H147 contact the TCR. Sequencing of the TCR expressed by both Th subset clones demonstrated different V beta usage as well as variation in the D-region sequence and length. Interestingly, realignment of the sequence of the CDR3 regions showed striking homology. This study demonstrates that Th1 and Th2 subsets can express very similar peptide specificities, while utilizing very different TCR V beta chains. These results suggest that the therapeutic modalities based on either peptide antagonists or antibodies specific for CDR3 may have limited effectiveness in treating autoimmune disorders, since they may also target the beneficial arm of the immune response.

Molecular epidemiological studies of Vibrio cholerae in Taiwan: genotyping by polymerase chain reaction and DNA sequencing

To type the Vibrio cholerae strains isolated from sporadic and epidemic cases in Taiwan, 28 toxigenic isolates were studied by sequencing polymerase chain reaction-amplified cholera toxin gene (ctx) fragments. Based on specific base substitutions on positions 115 and 203 of ctxB and comparison with previously published typing system from Centers for Disease Control and Prevention (Olsvik theta et al., J Clin Microbiol 1993; 31:22-5, Ref.1), two genotypes were identified. Cholera strains from imported seafood and sporadic cases in Taiwan had ctxB polymorphism of genotype 1; strains from patients in the 1962 Taiwan epidemic and Taiwan raised soft-shell turtles had ctxB polymorphism of genotype 3. Moreover, one toxigenic non-O1 strain was found to have other 11 different nucleotides in ctxB compared with those of the O1 and O139 strains. Therefore, DNA sequencing is a useful method for obtaining more complete genetic information. The approach could be improved by applying it to other more polymorphic regions of bacterial genome to obtain better epidemiological information among infected cases.

Genotypes of hepatitis C virus in Taiwan and the progression of liver disease

The existence of four genotypes of hepatitis C virus (HCV)--types 1a, 1b, 2a, and 2b--has been suggested based on variations in nucleotide sequences of the core region. The aim of this study was to investigate the prevalence of HCV genotypes in chronic type C liver disease in Taiwan and correlate distinct genotypes to severity of liver disease. The genotypes of 175 patients with chronic type C liver disease were determined by a polymerase chain reaction with type-specific primers. The prevalence of each genotype in Taiwan was as follows: type 1a, n = 1 (0.6%); 1b, n = 125 (71.4%); 2a, n = 21 (12%); 2b, n = 6 (3.4%); mixed types, n = 18 (10.3%); and unclassified, n = 4 (2.3%). The demographic and clinical features were comparable between patients with different genotypes, except that the mean peak serum transaminase levels of patients with double viruses and type 1b HCV infections were significantly higher than were those of patients with type 2a virus. Moreover, type 1b HCV was more prevalent in patients with liver cirrhosis alone or with hepatocellular carcinoma. In conclusion, type 1b virus is the predominant genotype in chronic hepatitis C in Taiwan, and type 1b virus and mixed infection may trigger more severe liver disease.

Large hepatitis delta antigen in packaging and replication inhibition: role of the carboxyl-terminal 19 amino acids and amino-terminal sequences

Hepatitis delta virus (HDV) encodes two proteins, the small delta antigen (SHDAg) and large delta antigen (LHDAg). The latter is identical to the former except for the presence of additional 19 amino acids at the C terminus. While SHDAg is required for HDV replication, LHDAg inhibits replication and, together with hepatitis B surface antigen (HBsAg), is required for the assembly of HDV. The last 19 C-terminal amino acids of LHDAg are essential for HDV assembly. Most of LHDAg (amino acids 19 to 146 and 163 to 195) had been shown to be dispensable for packaging with HBsAg. To discern whether the last 19 C-terminal amino acids solely constitute the signal for packaging with HBsAg, we constructed two LHDAg deletion mutants and tested their abilities to be packaged with HBsAg in cotransfection experiments. We found that deletion of amino acids 2 to 21 and 142 to 165 did not affect LHDAg packaging. This result suggested that only the last 19 C-terminal amino acids of LHDAg are required for packaging. We further constructed two plasmids which expressed c-H-ras with or without additional 19 C-terminal amino acids identical to those in LHDAg. Only c-H-ras with additional 19 amino acids could be cosecreted with HBsAg in the cotransfection experiment. This result confirmed that the C-terminal 19 amino acids are the packaging signal for HBsAg. We also tested the trans activation activity and trans-dominant inhibitory activity of the deletion mutants of SHDAg and LHDAg, respectively. In contrast to deletion of amino acids 142 to 165, deletion of amino acids 2 to 21 impaired the trans-dominant inhibitory activity of LHDAg. Deletion of amino acids 2 to 21 and 142 to 165 did not affect the trans activation activity of SHDAg. This result suggested that a functional domain which is important for the trans-dominant inhibitory activity of LHDAg exists in the amino terminus of HDAg.

Dissection of cross-reactivities using a panel of H-2Ld alloreactive T cell hybridomas

In order to explore the role which class I structure plays in alloreactivity, we have generated Ld-reactive T cell hybridomas by fusion of a dm2 anti-BALB/cJ MLR with the BW5147 cell line and examined their stimulation by the following class I molecules (alpha 1/alpha 2/alpha 3): Lq, Dq, dm1, Ld/Ld/Dd, Lq/Dq/Ld, and Q10/Q10/Ld. We found that their specificities differed in their patterns of cross-reactions and were reasonably representative of those present in the bulk population of MLR-generated CTLs. Ld/Ld/Dd and Q10/Q10/Ld stimulated the majority of the hybridomas, Lq and dm1 were recognized by over half of the panel, and Lq/Dq/Ld stimulated only modestly, while Dq was not recognized by any hybridoma. Correlation of these observed reactivities with class I structure suggests that putative TCR contact residues may play a significant role in recognition when compared to the polymorphic amino acid residues which control pocket specificity and peptide binding. Specifically, Lq and Dq possess very similar or identical pockets, in contrast to those of dm1 and Q10. However, Q10 has identical TCR contact residues to Ld, both on the alpha 1 and alpha 2 alpha helices, unlike Dq which is mismatched on both helices. Lq and dm1 are mismatched compared to Ld on only one helix. Thus, a molecular rationale for the cross-reactions observed in this study involves the direct participation of residues of class I molecules in allorecognition.

Prominent proliferative response of peripheral blood mononuclear cells to a recombinant non-structural (NS3) protein of hepatitis C virus in patients with chronic hepatitis C

The proliferative response of peripheral blood mononuclear cells (PBMC) to a recombinant non-structural (NS3) protein of hepatitis C virus (HCV) was studied in 41 patients with chronic hepatitis C. Of them, 28 had chronic persistent hepatitis (CPH) and 13 chronic active hepatitis (CAH). The positive proliferation rate of PBMC to the recombinant NS3 protein, T9Ag, was 66% in the 41 patients (77% in CAH versus 61% in CPH; P > 0.05) when stimulation index (SI) = 4 was set as the cut-off value. However, mean SI of CAH patients was significantly higher than that of CPH patients (8.3 +/- 5.2 versus 5.1 +/- 3.6; P < 0.05). Six other chronic hepatitis patients who were repeatedly negative for anti-HCV antibody but positive for serum HCV RNA also had an SI of > or = 4.0. The frequency of cellular immune response to the T9Ag is among the highest results obtained by using HCV antigens tested so far. Our studies thus indicate that NS3 is an immunologically important region of HCV for T cells. Moreover, the proliferative response to T9Ag may help to establish hepatitis C etiology in chronic hepatitis patients who are seronegative with currently available anti-HCV assays.

Quasispecies of hepatitis C virus and genetic drift of the hypervariable region in chronic type C hepatitis

The sequential variations of amino acid sequences in the hypervariable region (HVR)-1 of hepatitis C virus (HCV) and changes of viremia in 2 patients with different clinicopathologic courses of chronic hepatitis C were studied. By using polymerase chain reaction amplification, cloning, and sequencing of HVR-1, genetic heterogeneity of HCV was shown. The highest annual rate of consensus amino acid variation per 100 sites in HVR-1 of a patient with acute exacerbation was 15.4 versus 2.3 in a patient without acute exacerbation. The serial serum HCV titers were also quantified. An abrupt elevation of serum titer was associated with acute exacerbation, whereas constant viremia was observed when acute exacerbation did not occur. These results show that a quasispecies of HCV exists and patients with different courses of chronic hepatitis may have different sequential changes in virus titer and genetic drift of HVR-1.

Inhibition of alpha-fetoprotein production in a hepatoma cell line by antisense oligonucleotide analogues

alpha-Fetoprotein (AFP) is a fetal protein which is absent in adult serum. However, the AFP gene is expressed in some neoplastic cells. According to the literature, AFP may play a role in accelerating the growth of cancer cells. In this report, 15 meric antisense oligonucleotide analogues (phosphorothioates and methylphosphonates) and their chimeric forms, which were complementary to different regions of AFP mRNA, were synthesized, and their physical characteristics such as stability, melting temperature, and toxicity were compared. They were examined as to their inhibitor effects on the translation of AFP mRNA in a AFP-producing hepatoma cell line, HuH-7. We found that chimeric oligomers with methylphosphonate or phosphorothioate linkages at both the 5' and 3' ends were more effective than prototypic oligomers. Inhibition of 72% was achieved with a chimeric oligomer against the translational initiation region, at a concentration of 25 microM. No suppressive effect of the oligomers was observed on cell viability or albumin production, indicating the specificity of the inhibition.

Absence of infection in breast-fed infants born to hepatitis C virus-infected mothers

The role of breast-feeding in perinatal transmission of hepatitis C virus (HCV) was explored in 15 HCV-infected mothers and their infants. The 15 carrier mothers had anti-HCV titers ranging from 1:80 to 1:40,000 and also had HCV-ribonucleic acid with concentrations ranging from 10(4) to 2.5 x 10(8) copies/ml. Both anti-HCV antibody and HCV-ribonucleic acid were present in colostral samples in much lower levels, but none of the 11 breast-fed infants had evidence of HCV infection for up to 1 year of age. Thus breast-feeding seems safe for these infants.

Precore mutant of hepatitis B virus in childhood fulminant hepatitis B: an infrequent association

Serum HBV DNA from infants and children with fulminant hepatitis B (FHB) or acute self-limiting hepatitis B (AHB) and patients believed to be contamination sources was amplified by polymerase chain reaction (PCR) followed by direct sequencing of the precore region. A precore mutation from G to A at nucleotide 1896 was found in 5 of 14 FHB patients and in 3 of 10 AHB patients. Among the 10 infants who developed hepatitis during the first 6 months of age, the precore mutation was detected in only 2 of 7 with FHB and in 1 of 3 with AHB. In 1 infant with FHB, a shift from wild type to precore mutant predominance occurred in the serum virus population during the incubation period. Thus, the precore mutation is neither necessary nor sufficient to cause FHB in childhood, although its contributory role cannot be excluded. Factors other than precore mutations may be important in the pathogenesis of FHB.