Changes in free radical-metabolizing enzymes and lipid peroxides in the liver of Long-Evans with cinnamon-like coat color rats.

We report changes in free radical-metabolizing enzymes and the increased generation of lipid peroxides associated with extreme metal accumulation in the liver of the Long-Evans with cinnamon-like coat color (LEC) rat, a new mutant strain displaying hereditary hepatitis and subsequent hepatocellular carcinoma. The activity of free radical-metabolizing enzymes and lipid peroxides, and the concentration of metal in the liver were determined sequentially after birth. Mn-superoxide dismutase activity significantly increased immediately after the onset of hepatitis in LEC rats, whereas no remarkable change was observed in control rats. Cu, Zn-superoxide dismutase activity in LEC rats was similar to that in control rats. Glutathione reductase activity increased, while glutathione peroxidase activity was lower in LEC rats than in control rats throughout the observation periods. Lipid peroxides, estimated by thiobarbituric acid reaction, also increased 4- to 5-fold immediately after the onset of hepatitis in LEC rats. Copper concentration was 30- to 50-fold higher in the liver of LEC rats than in control rats, and the iron content also increased significantly before and after the onset of hepatitis. These findings suggested that an oxidant injury generated by toxic metals could be one of the factors responsible for hepatocellular damage in this unique hereditary hepatitis.

Mass screening for hepatocellular carcinoma: experience in Hokkaido, Japan.

Mass screening for liver cancer based mainly on abdominal ultrasound was begun in major cities of Hokkaido, Japan, in November 1981, to enable early detection and treatment of hepatocellular carcinoma (HCC). Serum alpha-fetoprotein levels were also measured to minimize false negative studies. Examinees included those who sought liver disease screening as well as high risk individuals: hepatitis B surface antigen carriers and those with a past or current liver disease, history of blood transfusion, family history of liver cancer, and more recently those with positive anti-hepatitis C antibodies. The examination was carried out on each Saturday and Sunday as one round, and by February 1992 48 rounds had been performed. A total of 8090 individuals were investigated, and HCC was detected in 91 with a detection rate of 1.12%. This rate was 1.6% among 5684 individuals who were selected for high risk. Cumulative rates of survival among these patients were 79.0% at 1 year, 43.8% at 3 years, 19.3% at 5 years and 15.4% at 7 years. These survival rates were comparable with those for the patients with HCC diagnosed during follow-up of chronic liver disease and treated at our hospital. The cost for detecting one HCC patient in this programme was 2,660,000 yen (approximately US$25,000), which was less than those for some other types of cancer in a similar setting. Considering the high detection rate in this programme, we feel that similar programmes should be encouraged and supported.

Importance of cytotoxic T lymphocytes in the rejection of transplanted hepatocellular carcinoma.

Fischer rats became resistant to syngeneic hepatocellular carcinoma (FAA-HTC1) cells on repeated sensitization with mitomycin C-treated FAA-HTC1 cells. In contrast, FAA-HTC1 cells injected into the liver killed normal control Fischer rats within 2 months. Histopathological studies revealed massive accumulation of mononuclear cells in the tumor tissues of sensitized rats that rejected syngeneic FAA-HTC1 cells, whereas very few mononuclear cells were found in the tumor tissues of control rats. Cell populations infiltrating the tumor tissues were identified by flow cytometric analysis. Mononuclear cells found within the regressing tumors of the sensitized rats were identified as mostly T cells, and two-thirds of these T cells were CD8-positive. Compared with the activity in control rats, the killer activity of mononuclear cells infiltrating tumors was significantly increased in the sensitized rats 7 days after tumor inoculation. Depletion of CD8(+) T cells significantly reduced the cytotoxicity of mononuclear cells infiltrating tumors obtained from sensitized rats. In contrast, depletion of CD16(+) cells reduced the cytotoxicity of mononuclear cells infiltrating tumors obtained from both control and sensitized rats. Furthermore, the CD16(+) cell-depleted fraction of mononuclear cells infiltrating tumors showed significant cytotoxicity against FAA-HTC1 cells, but failed to show cytotoxicity against other syngeneic tumor cells or allogeneic hepatoma cells.

[Diagnosis of type C chronic hepatitis using PCR technology].

Many studies have suggested that examination of a patient's serum for viral RNA by reverse transcriptase-polymerase chain reaction (RT-PCR) is the most sensitive and specific serological means of determining chronic HCV infection. Moreover, technique to quantify HCV RNA in serum using PCR technology has been developed, and diagnosis of HCV genotype by PCR with mixed primers has been used for diagnosis of type C hepatitis. Herein, we discuss the laboratory technique and significance of various PCR methods. HCV RNA can be detected by amplification technique of RT-PCR. Primers in the 5'-noncoding region are frequently used to detect HCV RNA, because the RNA sequence in this region is the most conserved. We usually perform 30 cycles of amplification with outer primers and another 30 cycles with inner primers (nested RT-PCR). Using this technique, HCV RNA was detected in 96% of anti-HCV-positive chronic hepatitis patients. This PCR technique gives us important information for the diagnosis of type C chronic hepatitis indicating HCV infection. The competitive PCR technique is usually used to quantify HCV RNA. This method is based on complification of the target RNA with known amounts of synthetic mutant RNA. The mutant RNA should be amplified by the same primers for amplifying target RNA, and should be distinguished from target RNA by the size of the amplified DNA product by making a deletion or restriction site artificially. Quantifying HCV RNA before interferon therapy is useful to predict the effectiveness of the therapy; patients with a large amount of HCV RNA tend to have a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

[Parasitic cirrhosis of the liver].

The shistosomiasis (caused by S. japonicum) has markedly decreased in Japan, as the most of other parasitic diseases. S. japonicum inhabits the portal venous system and its egg attacks the host's immunologic defences, resulting in inflammation and fibrosis of the liver. Laparoscopy reveals the characteristic, tortoise-shell-like liver, and liver biopsy is able to make a correct diagnosis. Portal-hypaertention is one of the most popular clinical features. Multilocular echinococcosis is a less frequent disease. However, this disease has gradually increased these several years in Hokkaido. This disease progresses to cirrhotic stage after long terms of latent and asymptomatic stages. This slowly enlarging lesion gradually occupies a large part of the liver and metastases to another intrahepatic parts or organs as well, just like a malignant tumor. Laparoscopically, the most of lesions appear ash-colored tumor with granular surface. Biopsy reveals the characteristic alveolar cysts with thick chitin membrane. Clinical features looks like liver cirrhosis or hepatoma.

cDNA cloning and chromosomal mapping of human N-acetylglucosaminyltransferase V+.

Human N-acetylglucosaminyltransferase V (GnT-V, EC 2.4.1.155) cDNA was isolated from a human fetal liver cDNA library. Oligonucleotide primers for polymerase chain reaction were designed according to the amino acid sequence of human GnT-V. Screening for the cDNA was carried out by plaque hybridization using PCR products of about 500 bp. Human GnT-V has 741 amino acids and six putative N-glycosylation sites. The homology to rat GnT-V is 88% at the nucleotide level and is 97% at the amino acid level, and there is one amino acid insertion. Using the cDNA clones as probe, five overlapping genomic clones have been isolated from a human phagemid DNA library. The GnT-V gene has been mapped to chromosome 2q21 using fluorescence in situ hybridization.