Biomedical subjects

M Ohto

Publications and source records attributed to M Ohto.

219 records · Page 13Linked to original sources

PubMedDate not supplied

Detection of hepatitis B virus precore stop codon mutants by selective amplification method: frequent detection of precore mutants in hepatitis B e antigen positive healthy carriers.

The precore region of hepatitis B virus (HBV) is indispensable for secretion of e antigen protein. Therefore, the precore stop codon mutants may play an important role in the process of e antigen seroconversion. However, the presence of the mutants in hepatitis B e antigen positive carriers has not been fully studied because of difficulties in detecting the mutants in the presence of large amounts of wild-type viruses. To overcome this, a sensitive method has been developed to detect the presence of G to A stop codon mutants at codon 28 of precore region. Primers for polymerase chain reaction (PCR) were devised to introduce restriction enzyme site Sty I for wild-type viruses and Dde I for the mutants. The amplification products with these primers were digested with Sty I to exclude the products from wild-type viruses. The remaining amplicon from precore mutants were re-amplified, and the presence of precore mutant was confirmed with Dde I digestion. The presence of precore mutants was examined in 61 HBV carriers by the method combining PCR and restriction enzyme digestion. Approximately 0.1% of precore mutant DNA among 10(6) copies of wild-type virus DNA was detectable by this method. The presence of the precore mutants was detected in seven of 10 (70%) e antigen positive asymptomatic carriers, and in 29 of 36 (81%) e antigen positive patients with chronic liver diseases, and in all 15 (100%) anti-e antibody positive patients with chronic liver diseases. This study revealed that a small amount of the precore mutants was present in the majority of HBV carriers.

Adult↗

PubMedDate not supplied

Chemosensitivity test for repeated arterial infusion chemotherapy by reservoir for unresectable hepatocellular carcinoma.

The experimental and clinical usefulness of a chemosensitivity test (Nuclear Damage Assay) was studied. Karyologic degenerative changes were observed as an indicator of drug sensitivity, in repeated arterial infusion chemotherapy (RAIC) using a reservoir for advanced hepatocellular carcinoma (HCC). In the experimental study, this sensitivity test was performed using five liver cell lines against 15 drugs. At the same time, the succinate dehydrogenase inhibition (SDI) test was also performed. Comparison of the results between these two tests gave a high consistency rate of 81%. Clinically, the karyologic sensitivity test was carried out in 135 patients with unresectable HCC. Drug sensitivity could be evaluated in as many as 89% of the total 135 patients. Of the patients, 43 received RAIC on an outpatient basis via a subcutaneously implanted reservoir. The objective response of RAIC on tumours of the 43 patients was evaluated as complete response, partial response, in 3 (9%) and 8 (23%) in 35 patients treated with positive drugs (positive group), and as 0 (0%) and 0 (0%) of 8 patients treated with negative drugs (negative group), respectively. As regards the prognosis, 1 year and 1.5 year survival rates were 70 and 45% in the positive group, and 42 and 0% in the negative group, respectively. As objective response in the positive group tended to be better than that in the negative group, and prognosis in the positive group was significantly better than that in the negative group, this sensitivity test appears to contribute to the improvement of therapeutic results if used to select drugs suitable for RAIC for advanced HCC.

Adult↗

PubMedDate not supplied

Present trends in Japan with regard to epidemiology and clinical features of hepatocellular carcinoma.

Hepatocellular carcinoma epidemiology has undergone great changes in Japan. Life span, new diagnostic procedures and viral infections obtained through intravenous injections have contributed to these changes. The aetiological aspects and clinical features of HCC should be reappraised to account for the current use of techniques such as US and CT in the early diagnosis of HCC. In Japan most HCC seem to be HBV and/or HCV associated whereas small HCC seem to be HCV-associated more so than large HCC. The usual clinical symptoms and signs are somewhat useless and of limited value while the newer techniques permit an early clinical diagnosis of small HCC. This diagnostic advancement has also permitted a remarkable progression in HCC therapy.

Carcinoma, Hepatocellular↗