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An unenveloped single-stranded DNA virus (TTV) has been reported in association with posttransfusion and acute and chronic hepatitis of unknown etiology. DNA of TTV was tested for by polymerase chain reaction with heminested primers in 127 patients with chronic liver disease and 105 healthy blood donors in Thailand. TTV DNA was detected in 23 (59%) of the 39 patients without hepatitis B surface antigen or RNA of hepatitis C virus, at a frequency significantly higher than the detection in 21 (36%) of the 59 patients with HBsAg (P < 0.05) or in 38 (36%) of the 105 blood donors (P< 0.05). Among patients with chronic liver disease, TTV DNA occurred in those with liver cirrhosis and hepatocellular carcinoma more frequently than in those with chronic hepatitis (35 of 65 or 54% vs. 20 of 62 or 32%, P< 0.05). There were no differences in age, sex, or markers of infection with hepatitis B, C and GBV-C/HGV viruses, indicating a mode of transmission of TTV different from those of the other hepatitis viruses. Phylogenetic analysis indicated three different genotypes of TTV with six distinct subtypes in Thailand. Based on these results, TTV would have a role in the development of chronic liver disease of unknown etiology in Thailand.

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From November 1993 to December 1994, the seroprevalence of anti-HCV, HBsAg was studied among 346 HIV-infected persons (asymptomatic HIV-infected persons and AIDS patients) and 1,023 subjects from the general population (including 119 cord blood samples). The prevalence of anti-HCV, HBsAg among HIV-infected patients aged 15-45+ years was 11.0 and 11.6 per cent respectively which is significantly higher than the comparable levels for the general population (1.9% and 4.7%) in the age group 15-44 years. There was no statistically significant association of anti-HCV and HBsAg prevalence among 200 asymptomatic HIV-infected carriers and 146 AIDS patients. Assays for anti-HCV among blood donors are highly recommended to reduce the development of liver disease or cirrhosis in the immediate future.

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Nine (10%) out of 90 hepatitis C virus (HCV) isolates from hepatitis patients and commercial blood donors in Thailand were not classifiable into any of genotypes I/1a, II/1b, III/2a, IV/2b, V/3a or VI/3b by RT-PCR with type-specific primers deduced from the HCV core gene. These isolates were sequenced over a 1.6 kb stretch of the 5'-terminal sequence and 1.1 kb of the 3'-terminal sequence covering 30% of the entire genome. Based on two-by-two comparison and phylogenetic analyses of the nine Thailand isolates among themselves and with known full or partial sequences of previously reported HCV isolates, the Thailand isolates were classified into five genotypes not reported previously, viz. 6b, 7c, 7d, 9b and 9c. Along with HCV isolates reported already, they make at least nine major genetic groups of HCV which further break down into at least 28 genotypes with sequence similarity in the E1 gene (576 bp) of < or = 80%. As many more HCV isolates of distinct genotypes are expected to be found throughout the world, it will become increasingly difficult to classify them by comparison of any partial sequences of the genome. Complete sequence data will be required for the full characterization and classification of HCV genotypes.

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A case of an elderly female whose clinical manifestations were atypical in view of physiologic aging changes and multiple pathology commonly found in the geriatric group. The liver abscess had presented clinically and radiologically like a hepatic malignancy and pus was obtained during the process of liver biopsy. Even though anchovy-like pus suggested amebic in origin, the microscopic exam showed numerous polymorphonuclear leucocyte and the culture both from the blood and pus grew Klebsiella spp. as well as the study for E. histolytica antibody was also negative. Pyogenic liver abscess was the working diagnosis and indicated for surgical drainage. Adult polycystic liver disease was found intraoperatively and the liver pathology did reveal the presence of many amebae in the cavity of the right lobe of the liver. After the administration of ceftriaxone and metronidazole as well as the surgical drainage, the patient recovered uneventfully within sixteen days of admission.

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Hepatitis C virus (HCV) RNA and genotypes, as well as markers of hepatitis B virus infection, were surveyed in 171 patients with chronic liver disease, 276 patients with chronic renal failure, and 961 blood donors in Thailand. HCV RNA was detected in 30 (23%) of 128 patients with non-alcoholic chronic liver disease and hepatitis B surface antigen (HBsAg) in 60 (47%), and both HCV RNA and HBsAg in 3; the cause of liver disease was not established in 41 (32%) patients. HCV RNA was detected in 44 (20%) of 221 patients on maintenance hemodialysis or with kidney transplantation, but in none of 55 patients on peritoneal dialysis. Antibodies to synthetic HCV core peptides were detected in 39 (4.1%) of sera from 961 blood donors, and HCV RNA was detected in 8 (0.8%). Of the 90 HCV RNA samples from patients and donors, genotype V prevailed (46%) followed by II (22%), I (14%), III (3%), and VI (2%); genotypes were not classifiable into any of I-VI in the remaining 10%. There were six sera which contained HCV RNA, but were without antibody to HCV detectable by the second-generation enzyme immunoassay. HCV RNA titers were high in four patients with kidney transplantation, but low in one patient with chronic liver disease and one patient on maintenance hemodialysis. HCV RNA at high titer (> or = 10(4)/ml) was not classifiable in one patient. These results indicate HCV of novel genotypes in Thailand, seronegative HCV infection in patients with kidney transplantation, and a low risk of HCV infection in patients treated by peritoneal dialysis.

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A two-year study of endoscopic brush cytology and biopsy histology was carried out in 63 patients suspected of having malignant lesions in the stomach and the eosophagus. The study was designed to evaluate the accuracy and usefulness of combined cytological examination with biopsy histological examination in the diagnosis of malignancy of the upper gastrointestinal tract. The rate of diagnostic accuracy of the combined technique was found to be high and comparable with those of other published studies. Correlations between the cytological and histological findings were observed in 52 cases (82.53%). The combined method detected malignancy in 27 cases, whereas, the brush cytology alone detected malignancy in 19 cases. The findings of our study indicate that combined brush cytology and biopsy histology under direct vision using fibrescope are of value for the diagnosis of gastroeosophageal malignancy.

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The prevalence of H.pylori in Thailand is high compared with Western countries and is the same as in China. We suggest either rapid urease test (CLO test) or Giemsa stain to be a rapid, reliable and convenient detection method for H.pylori and is also suitable for use in follow-up studies by gastroenterologists.

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Evidence is accumulating that Helicobacter pylori infection plays a major contributory role in peptic ulcer disease [Duodenal Ulcer (DU) and Gastric ulcer (GU)] and non-ulcer dyspepsia (NUD). We, therefore, studied prospectively 210 consecutive patients with upper gastrointestinal symptoms (62 DU, 38 GU and 110 NUD) to determine the prevalence of H. pylori infection and to investigate their association with histological gastritis. Using endoscopic biopsy of the gastric antrum for diagnosing H. pylori infection by Campylobacter-like Organism (CLO) test, histology or bacteriology, the overall prevalence of H. pylori was 63.3 per cent. When H. pylori infection was related to diagnosis, DU had the highest prevalence rate of H. pylori infection (66%), GU and NUD were less frequently associated with H. pylori infection (55% and 44% respectively). We found a close association between H. pylori infection and histologically antral gastritis, in that 72.7, 61.7, and 62.6 per cent of the DU, GU and NUD patients with antral gastritis (respectively) had H. pylori infection. In contrast, none of these patients seen with normal antrum had H. pylori infection. We also found that the prevalence of H. pylori in our patient series was not age related. Of the three procedures used to demonstrate H. pylori, the CLO test and histological staining method gave the highest yields of 84.9 and 79.6 per cent respectively, and bacteriology in only 44.3 per cent, we conclude that the prevalence of H. pylori infection in Thai patients with upper gastrointestinal symptoms is high. H. pylori infection commonly occurs in the patients with antral gastritis, suggesting a possible etiologic role for the bacterium in the histologic lesion.

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The prevalence of anti-HCV is about 1% among the blood donor population. Among 98 children with hemoglobinopathy, age ranging from 2-16 years, anti-HCV was detected in 14 (14%). The average age of the positive group was significantly higher than the negative (10.6 + 2.9 vs 8.1 + 3.9 years P less than 0.05). Numbers of transfusions were 54 + 39 in positive cases as compared to 38.5 + 36 in negative cases but this and were not statistically significant. Anti-HCV was found in 0/18, 0/3 and 0/12 in the HBsAg-positive chronic hepatitis, cirrhosis and hepatocellular carcinoma respectively, whereas it was found in 10/24 (42%), 3/13 (23%) and 0/8 in the HBsAg-negative chronic hepatitis, cirrhosis and hepatocellular carcinoma group. In an adult multiple transfused group of 153 patients who suffered from various hematologic diseases 50 (32.6%) were positive for anti-HCV. If the presence of anti-HCV indicates the presence of hepatitis C virus in the body, we expect that many of these patients will have chronic hepatitis and subsequently cirrhosis. Therefore screening of all donor blood should be adopted in all institutions concerned.

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The specificity of five monoclonal antibodies, three raised against hepatitis B surface antigen (HBsAg) particles and two against envelope polypeptides, was tested for on a panel of 366 sera containing HBsAg of various subtypes (131 adw, 146 adr, 39 ayw and 50 ayr). Three monoclonals bound to HBsAg irrespective of subtypes, and therefore, were directed to the common antigenic determinants of HBsAg. Of these, two raised against particles (No. 824 and No. 7922) did not bind with reduced HBsAg particles. The other raised against peptides (No. 5124) bound to reduced HBsAg particles. It did not, however, bind to reduced and alkylated HBsAg particles, thereby indicating that it was directed to an epitope involving cysteine residues not contributing to the conformation. The remaining two monoclonals were directed to subtypic determinants not identical to any of d, y, w and r determinants. The subtypic determinant detectable by one of them (No. 4403), raised against HBsAg polypeptides, markedly increased after reduction of HBsAg particles with or without alkylation. In contrast, the subtypic determinant, detectable by the other monoclonal (No. 2155) raised against particles, substantially decreased after reduction. Non-identity of common or subtypic determinants detectable by the five monoclonals were established by blocking tests in which labeled antibody was competed by non-labeled antibody, of a homologous or heterologous specificity, for the binding with HBsAg. These monoclonals would be useful in studies for immunochemical configuration of HBsAg particles and epidemiology of novel subtypic determinants.

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