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Biomedical subjects

G Kuo

Publications and source records attributed to G Kuo.

At least 55 records · Page 3Linked to original sources
PubMed1991

Role of hepatitis C virus in non-B chronic liver disease.

To assess the contribution of the recently identified hepatitis C virus to chronic liver diseases of unknown cause and chronic hepatitis attributed by exclusion to non-A, non-B hepatitis, we tested for antibody to hepatitis C in hepatitis B surface antigen-negative patients with a spectrum of chronic liver diseases. Antibody to hepatitis C virus, a marker of hepatitis C infection, was detected with a first-generation radioimmunoassay at the following frequencies in the following patient groups: 69% of transfusion-associated non-A, non-B hepatitis; 53% of non-transfusion-associated non-A, non-B hepatitis; 26% of hepatitis B surface antigen-negative hepatocellular carcinoma; 8% of cryptogenic cirrhosis; 5% to 7% of autoimmune chronic liver diseases; 19% of patients with miscellaneous types of chronic liver disease; and 0.67% of healthy controls. Among non-transfusion-associated cases, 81% with a history of intravenous drug use but only 18% with occupational exposure as health workers had antibody to hepatitis C virus. Among cases of hepatocellular carcinoma, 63% of Japanese patients but only 11% of American patients had evidence of hepatitis C infection. Comparison in a subgroup of 79 serum samples of a second-generation radioimmunoassay with the first-generation assay demonstrated a 12% increase in antibody frequency from 30% to 42%. We conclude that hepatitis C plays a substantial role in transfusion-associated and non-transfusion-associated non-A, non-B hepatitis as well as in hepatocellular carcinoma, especially in Japan, a limited role in cryptogenic cirrhosis, and essentially no role in autoimmune chronic liver diseases. Application of more sensitive immunoassays will increase the frequency of antibody seropositivity in all subgroups, but relative distinctions among risk groups are likely to remain.

Asian↗
PubMed1991

The role of chronic viral hepatitis in hepatocellular carcinoma in the United States.

Although hepatocellular carcinoma is a relatively uncommon tumor in the United States, it is quite common in sub-Saharan Africa and the Far East, where most cases are associated with infection with the hepatitis B virus. We have studied 99 American patients with hepatocellular carcinoma for evidence of hepatitis B or hepatitis C viral infection and compared these findings to those in a group of matched controls with other cancers. The two groups differed in proportion, with hepatitis B surface antigen in serum being significantly higher in patients with hepatocellular carcinoma (7% vs. 0%, p = 0.009). Antibody to hepatitis C virus was also found more frequently in patients with hepatocellular carcinoma (13% vs. 2%, p = 0.002). The relative risk for hepatocellular carcinoma in hepatitis B surface antigen-positive patients was calculated to be 17.3 and for antibody to hepatitis C virus to be 7.3. The attributable fraction of cases related to the hepatitis B surface antigen carrier state was 6.7% and for patients infected with the hepatitis C virus was 11.4%. Approximately three quarters of cases of hepatocellular carcinoma did not have evidence of either hepatitis C or hepatitis B virus infection. These findings provide strong evidence that hepatitis C virus infection is associated with the development of hepatocellular carcinoma, and in the United States may even play a more important role than the hepatitis B virus.

Adolescent↗
PubMed1990

Hepatitis C viral cDNA clones isolated from a healthy carrier donor implicated in post-transfusion non-A, non-B hepatitis.

Using a specific hepatitis C virus (HCV) antibody assay, positive blood donors responsible for the transmission of post-transfusion non-A, non-B hepatitis (PT-NANBH) were identified. cDNA fragments were isolated from one of the plasma samples of such healthy HCV carriers by using polymerase chain reactions. Nucleotide (nt) sequence analyses of the cDNA from three different regions of the viral genome revealed that they were derived from a Japanese HCV isolate that was similar but not identical to the prototype HCV previously isolated from a chronically infected chimpanzee. Homology at the nt and amino acid levels was comparatively lower in the presumed structural region than in putative nonstructural regions. This result not only confirms that HCV antibody-positive blood contains infectious HCV, but suggests the existence of different type(s) of HCV.

Amino Acid Sequence↗
PubMed1990

Hepatitis C antibody and chronic liver disease in haemophilia.

A radioimmunoassay was used to detect antibodies to hepatitis C virus (anti-HCV) in 154 patients with haemophilia. Prevalence of anti-HCV was associated with exposure to clotting factor concentrates. 76 of 129 (59%) who had received factor VIII or IX had anti-HCV: 42 of 55 (76%) who required over 10,000 units of concentrate annually had anti-HCV, compared with 34 of 74 (46%) who required less, and 0 of 25 patients who had never received concentrates. Anti-HCV were significantly more common in patients seropositive for antibodies against human immunodeficiency virus (anti-HIV) or with markers of previous hepatitis B infection than in those without anti-HIV or hepatitis B markers (88% vs 39% and 75% vs 46%, respectively). 5 of 23 (22%) haemophiliacs treated only with heated concentrates had anti-HCV compared with 71 of 106 (67%) patients who received unmodified products. 35 patients with chronic liver disease underwent liver biopsy: histological examination showed features associated with post-transfusion hepatitis in 24, all of whom were anti-HCV-positive; of the other 11 patients with no histological features of non-A, non-B hepatitis, 5 were anti-HCV-positive. HCV appears to be the major predisposing factor for most non-A, non-B hepatitis and chronic liver disease in haemophilia.

Adolescent↗
PubMed1990

Hepatitis C virus antibodies in southern African blacks with hepatocellular carcinoma.

380 southern African blacks with hepatocellular carcinoma and 152 controls were studied. Antibodies to hepatitis C virus (HCV) were found in 110 patients and 1 control. 184 patients had evidence of current infection with hepatitis B virus (HBV) and 122 had had infection with this virus in the past. Only 47 patients had no markers of HCV or HBV infection. Among patients positive for HCV, there was a higher proportion of women and urban dwellers, and the average age was higher. In southern Africa, HCV is associated with hepatocellular carcinoma but HBV is present in a higher proportion of patients.

Adolescent↗
PubMed1990

Detection of hepatitis C viral sequences in non-A, non-B hepatitis.

The role of hepatitis C virus (HCV) in post-transfusion non-A, non-B hepatitis (NANBH) was investigated by analysing clinical samples for both HCV RNA by cDNA/polymerase chain reaction and antibodies against C100-3 by radioimmunoassay. Of fifteen chronic NANBH patients and one patient with chronic cryptogenic liver disease, ten were positive for anti-C100-3 and seven of the ten had viral sequences in their livers. However, two patients negative for anti-C100-3 also had substantial levels of HCV RNA in their livers. In acute post-transfusion NANBH (one surgical patient and two experimentally infected chimpanzees), HCV RNA was detected in the absence of anti-C100-3. In addition, infectious plasma from a seronegative patient with acute post-transfusion NANBH and a seronegative pool of plasma from a chimpanzee with chronic post-transfusion NANBH had high levels of HCV. These findings show that anti-C100-3-positive patients with chronic post-transfusion NANBH are likely to be viraemic; confirm that antibodies to C100-3 are a marker for infectivity; and suggest that the prevalence of HCV infections may be underestimated from the frequency of antibodies to C100-3 alone.

Animals↗
PubMed1990

Epidemiology of hepatitis C virus. A preliminary study in volunteer blood donors.

In a survey carried out from 1985 through 1986, volunteer blood donors to The Greater New York Blood Program were tested for two surrogate markers for non-A, non-B hepatitis--elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen. Stored serum samples from selected donors were also recently tested for antibody to hepatitis C virus (anti-HCV). Anti-HCV was detected in 0.9% to 1.4% of donors and was higher in black and Hispanic donors than in white donors. Anti-HCV prevalence increased with increasing age through the fourth decade of life, but decreased thereafter, possibly reflecting the disappearance of detectable antibody with time. Anti-HCV correlated with both alanine aminotransferase level and the presence or absence of antibody to hepatitis B core antigen. These associations suggest that donor screening for elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen was, as expected, at least partially effective in preventing transfusion-associated non-A, non-B hepatitis. The detection of anti-HCV in donors who have neither an elevation of alanine aminotransferase level nor presence of antibody to hepatitis B core antigen suggests that donor screening for anti-HCV will further reduce the risk of transfusion-associated hepatitis.

Adult↗
PubMed1990

Non-A, non-B hepatitis and antibody to hepatitis C virus.

Stored serum samples from the Transfusion-transmitted Viruses Study in the 1970s were tested for the presence of antibody to hepatitis C virus (anti-HCV). Single specimens from five control subjects who did not receive transfusions tested negative for anti-HCV. Of four control subjects who did not receive transfusions and who developed non-A, non-B (NANB) hepatitis after hospitalization, three remained anti-HCV negative; the fourth person with postoperative NANB hepatitis tested anti-HCV positive before the operation. Five transfusion recipients with posttransfusion hepatitis B virus infection remained seronegative; a sixth with NANB hepatitis as well as hepatitis B virus infection had seroconversion for anti-HCV. Five of nine transfusion recipients with NANB hepatitis had anti-HCV seroconversion. These results show that present anti-HCV testing demonstrates an etiologic basis for approximately half of the cases of transfusion-associated NANB hepatitis, particularly those that develop chronicity. Although cases of NANB hepatitis without seroconversion may be explained otherwise, they may be caused by another, presently unidentified, virus.

Blood Transfusion↗
PubMed1990

Hepatitis C-associated hepatocellular carcinoma.

In the United States, a large percentage of patients with hepatocellular carcinoma are serologically negative for hepatitis B. We conducted a retrospective study to determine the prevalence of hepatitis C antibody in the sera of 59 patients with hepatocellular carcinoma who were HBsAg-negative and had no evidence of alcoholic liver disease, primary biliary cirrhosis, autoimmune hepatitis, hemochromatosis or alpha 1-antitrypsin deficiency. Twenty patients (34%) were hepatitis C antibody-positive and hepatitis B core antibody-negative. All twenty patients had underlying cirrhosis, and seven (35%) had histories of transfusions. Eleven (19%) additional patients were also hepatitis C antibody-positive but were hepatitis B core antibody-positive as well. Twenty-one (36%) patients were both hepatitis C antibody- and hepatitis B core antibody-negative and seven (12%) were hepatitis C antibody-negative but hepatitis B core antibody-positive. The prevalence of hepatitis C antibody was also determined among three other population groups serving as controls and found to be 14% in 28 HbsAg-positive patients with hepatocellular carcinoma, 44% in 76 patients with cryptogenic cirrhosis and 0.5% in 200 consecutive volunteer blood donors. We conclude that hepatitis C antibody is prevalent among patients with hepatocellular carcinoma and may therefore be a common causative agent of this disease. A significant number of patients with and without cirrhosis, negative for hepatitis C antibody and hepatitis B core antibody, remain without a discernible cause for this malignancy. Perhaps a second- or third-generation test will detect hepatitis C antibody in some of these patients.

Carcinoma, Hepatocellular↗
PubMed1990

Parenterally transmitted non-A, non-B hepatitis: virus-specific antibody response patterns in hepatitis C virus-infected chimpanzees.

An established chimpanzee model of parenterally-transmitted non-A, non-B hepatitis was used to define virus-specific immune response patterns in acutely and persistently infected animals. Serial bleedings were obtained from 23 chimpanzees that had been experimentally infected with an isolate of hepatitis C virus, originally recovered from contaminated lots of factor VIII (antihemophilic) materials. Sera were assayed for the presence of antihepatitis C virus by a newly developed radioimmunoassay procedure that incorporated recombinant DNA-expressed viral antigen as a reagent. Twenty-one of 23 hepatitis C virus infected animals were shown to acquire antihepatitis C virus, most within 2-8 weeks after the major peak of alanine aminotransferase activity. All chimpanzees with biochemical, electron microscopic, and histological evidence of chronic disease clearly acquired antibody; 14 of 16 animals observed through the acute phase of disease were also shown to acquire antibody. A booster effect or anamnestic response was noted in two chimpanzees (one of which was negative for antihepatitis C virus following the acute phase of disease) after challenge with hepatitis C virus. Antihepatitis C virus was not neutralizing, because some animals with high levels of antibody were also shown to have high titers of circulating hepatitis C virus. The development and maintenance of anti-hepatitis C virus appears to reflect concomitant virus replication and high potential for infectivity.

Animals↗
PubMed1990

Blood screening for non-A, non-B hepatitis by hepatitis C virus antibody assay.

Hepatitis C virus (HCV) antibody was detected in 1499 donor sera by radioimmunoassay using an antigen expressed in yeast from a cDNA clone of the HCV genome. Eighteen samples over 4200 counts per minute (cpm) were considered to contain infectious HCV because these recipients developed typical posttransfusion non-A, non-B hepatitis after transfusion. The antibody-positive sera were all within the normal range of ALT levels. This assay system is thus useful for the screening for blood transfusion.

Adult↗
PubMed1990

Detection of antibody against antigen expressed by molecularly cloned hepatitis C virus cDNA: application to diagnosis and blood screening for posttransfusion hepatitis.

A cDNA clone has been derived from the plasma of a chimpanzee with chronic non-A, non-B viral hepatitis (NANBH). We have assayed for antibodies reacting with the encoded antigen in sera from posttransfusion hepatitis patients (643 samples from 23 patients) and their corresponding donors collected during the past 10 years in Japan. The antibody was detected in 15 out of 17 (88.2%) posttransfusion NANBH (PT-NANBH) patients whose sera over time displayed multiple alanine aminotransferase (ALT) peaks. In general, the antibody was detected after several peaks of serum ALT elevations and, once detected, it persisted for years. In contrast to the patients of chronic hepatitis, the antibody was barely detected in patients with a single episode of ALT elevation (1 out of 6). Of the 15 well-defined cases of PT-NANBH that showed multiple ALT peaks and hepatitis C virus seroconversions, 11 (73.3%) were shown to be transfused with at least one unit of blood positive for the antibody. The retrospective analysis showed that all tested donor blood found to be positive for the antibody had been transfused to recipients who afterwards developed NANBH. These data strongly suggest that the cloned cDNA originated from an etiological agent of NANBH termed the hepatitis C virus. Furthermore, the present study demonstrates that had the screening been done with the anti-hepatitis C virus assay, 11 out of 17 (64.7%) cases of chronic PT-NANBH and 1 out of 6 (16.6%) acute PT-NANBH would have been prevented. The antibody assay thus can be used for diagnosis and blood screening for PT-NANBH.

Adult↗
PubMed1990

Hepatitis C virus: the major causative agent of viral non-A, non-B hepatitis.

A 'blind' recombinant immunoscreening approach, of general application to studies of infectious diseases, was used to clone and identify the genome of the previously uncharacterized non-A, non-B hepatitis (NANB) virus. This agent is a positive-stranded RNA virus that appears to be distantly related to the flaviviridae family. A recombinant viral antigen (C100-3) was used to develop a capture assay for circulating antibody. Data obtained using this assay indicate that this agent, termed the hepatitis C virus (HCV), is the major cause of post-transfusion, community-acquired and cryptogenic, NANB. Anti-C100-3 antibody appears to be directed towards dominant, non-structural viral epitopes. It is a non-neutralising antibody that develops generally late in infection and is a particularly good marker of chronic, persistent viraemia. Many asymptomatic but infectious blood donors can now be detected using this antibody assay. HCV is associated with the development of hepatocellular carcinoma and possibly, other liver diseases.

Amino Acid Sequence↗