Hepatitis E, an enterically transmitted non-A, non-B hepatitis, is a serious viral infection that occasionally causes large epidemics in developing countries. In developed countries, the disease only appears sporadically due to the transmission routes, and it is considered to be less important. The hepatitis E virus (HEV) cannot grow in cultured cells and no reliable assay system has ever been developed. In addition, the present diagnostic are not perfect, and actual rates of HEV infection may be underestimated. Highly purified empty virus-like particles (VLPs) of HEV have been produced by the use of a recombinant baculovirus vector in insect cells. Using these VLPs as an antigen, an enzyme-linked immunosorbent assay (ELISA) for antibodies to HEV was developed. A panel of 164 sera that were randomized and coded, and sera collected periodically from three patients with hepatitis E were used for the evaluation. The sensitivity of the assay was shown to be equal to or better than that obtained in previous research that used the same serum panel. The ELISA demonstrated that the serum IgM level of the patients was highest at the onset of the clinical illness and then rapidly decreased. In contrast, a high level of circulating IgG antibody titers lasted for more than 4 years. In Japan, a non-endemic country, the prevalence of the IgG class antibody to HEV in healthy individuals was found to range from 1.9% to 14.1%, depending on the geographical area. Only one out of 900 (0.1%) serum samples was IgM-positive. The IgM class antibody to HEV was detected in 10.8% of non-A, non-B, and non-C acute hepatitis patients in northeast China, whereas none of the patients in Korea had the IgM antibody. The ELISA utilizing the VLPs is sensitive and specific in its detection of the IgM and IgG antibodies to HEV. The ELISA is therefore useful for diagnosing HEV infection and for seroepidemiological study of hepatitis E.

In this study, we developed a continuous process using extruders in a pilot plant for recycling silane cross-linked polyethylene (silane-XLPE) via chemical reaction in supercritical alcohol. As a first step, an autoclave was employed to reveal the effects of temperature and pressure on the reaction that selectively decomposes the siloxane cross-linking bonds. Selective decomposition of the siloxane bond was found to occur in the supercritical alcohol. In the next step, an extruder was used to continuously feed silane-XLPE into a tube reactor containing supercritical alcohol. Silane-XLPE was then extruded with an injection of supercritical alcohol. Alcohol remained in the supercritical state inside the cylinders of the extruder and the tube reactor. The recycled polyethylene (PE) was continuously extruded from the reactor at a rate of 14 kg/h. The product produced by this continuous process was the same as that from the autoclave. The mechanical properties of the recycled PE satisfied the requirements for use as a wire and cable insulation material. These results suggest that the extruder proved to be useful for the continuous denaturation of a cross-linked polymer in supercritical alcohol.

No abstract

The northern district of R Town, Yamagata Prefecture, Japan, experienced an epidemic of acute hepatitis C during the 6 years following 1967. A mass survey health examination for hepatitis C virus (HCV) infection was performed on the inhabitants of this district aged 6 or over (4,655 people). Of the 3,094 inhabitants (66.5%) examined, 602 (19.5%) were anti-HCV antibody (anti-HCV) positive. Of the 602 anti-HCV positive subjects, 444 (73.7%) showed an anti-HCV cutoff index of over 4.0 (high titer), 54 (9.0%) showed 3.0-4.0 (middle titer), and 104 (17.3%) showed an index of under 3 (low titer). One hundred and sixty subjects, randomly selected, were examined for HCV RNA by nested polymerase chain reaction, and positive reactions were detected in 125 subjects (78.1 %). The anti-HCV positive rate differed greatly between subjects younger than 40 years (18/1,289 ; 1.4%) and those 40 or over (584/1,805 ; 32.4%). Those who had lived in this district since before the acute hepatitis C epidemic had a high rate of positive anti-HCV. Among the 47 hamlets in this farming district, the hamlet with the highest rate (71.4%) was surrounded by other hamlets where the rates decreased as the distance from the high rate hamlet increased.The study suggested a marked regional accumulation of HCV infection in this district and an age-related difference in HCV infection rates. The cause of the accumulation was not identified, although the HCV infection in this district may have been spread during or before the acute hepatitis C epidemic and produced many HCV carriers.

We studied the age- and sex-specific prevalence of hepatitis C virus (HCV) infection and aminotransferase abnormalities as well as histological changes in the liver associated with HCV infection. Of the eligible 3,707 inhabitants aged 6 years and older in an HCV infection epidemic area 2,382 (64.3%) were examined. The anti-HCV positivity rate was 20.7% on average and increased according to age. Age was the most potential risk indicator for anti-HCV positivity by multiple stepwise regression analysis. The HCV RNA positivity rate in females with anti-HCV was significantly lower than that in males. However, as the age of females increased, the HCV RNA positivity rate became higher. The proportion of subjects with aminotransferase abnormalities among HCV RNA-positive subjects was significantly lower in females than males. Aminotransferase abnormalities significantly increased with age in females. In subjects with abnormal aminotransferase levels, nearly half of the HCV RNA-positive females were aged 50 or older and also nearly half of the male subjects showed CAH2B or liver cirrhosis, while most of the HCV RNA-positive females younger than 50 exhibited histological findings consistent with CPH. In conclusion, age was the principal risk indicator for HCV infection in this area. Females, especially those younger than 50, both biochemically and histologically showed less severity of HCV infection than males. Gender and age might have effects on the outcome of HCV related liver disease.