Biomedical subjects
Publications and source records attributed to N Sakurada.
Preliminary screening of antiviral AIDS drugs has been carried out using three different in vitro assay systems. Among 138 samples tested, two were found to inhibit the growth of HIV in vitro. Neither of the positive samples has hopeful signs, as the ranges of effective doses of the samples are very narrow.
Preliminary screening for antiviral AIDS drugs has been carried out using three different in vitro assay systems. Among 154 samples tested, nine were found to inhibit the growth of HIV in vitro. One of nine has a hopeful sign, as the range of effective doses of the sample is wide.
In Japan, recently, an increasing number of heterosexual contacts have resulted in HIV infection and warns of an explosive outbreak in a few years. Both the United States and Thailand experienced such explosive outbreaks in the past, through contacts with a large number of intravenous drug users. As the results of a survey in Japan showed a low HIV positive rate among intravenous drug users, an explosive outbreak might be avoided in the future. Since recognition of AIDS in 1981, many valuable new observations have been made. HIV can infect a variety of human cells lacking the CD4 molecule, such as liver cells and some nerve cells. Some human T cells show differential susceptibility despite high expression of the CD4 molecule. Biological properties such as high replication and syncytium inducing isolates are associated with a decrease in CD4 cells. The precursor frequency of HIV-1 expressing cells was about 1/1000 and that of HIV-1 DNA was at least 1/100 CD4 cells in AIDS patients. Soluble CD4 analog binds up gp120 with an affinity and specificity comparable to intact CD4 and is capable of neutralizing the infectiousness of HIV-1. The resistance of HIV-1 to soluble CD4 neutralization is largely determined by the sequence of the V3 loop in gp120. Protection of chimpanzees from infection by HIV-1 after vaccination with recombinant gp120 and prevention of HIV infection by CD4 immunoadhesin were confirmed. Unexplained CD4 T-lymphocyte depletion without evidence of HIV infection has been noted since 1989 and epidemiologic and laboratory investigations are in progress.
A serological survey was conducted on 4,080 swine sera collected for the years 1985-90. The swine sera positive to A/New Jersey/8/76 (swine type H1N1) strain were observed in annual (10-20%) and monthly (20-40%) incidences during the observation period except for occasional months. Antibodies to recent human H1N1 viruses in swine were recognized in relation to the human H1N1 influenza epidemics. Antibody responses of swine to human H3N2 strains appeared irrespective of human epidemics with the virus in the years 1985-87. However, in 1988 almost no antibodies to three human H3N2 isolates of 1983-88 were observed for this year except a few months though the human epidemic occurred in the area. Although in 1989-90 many swine had antibodies to the three strains in the percentage of 3 to 35, no antibody to the latest isolate, A/Hokkaido/20/89 (H3N2), was found for almost all the months of both years. These findings differed markedly from the possible relationship between the prevalence of H3N2 virus-antibodies in swine and the human influenza epidemics, which were described previously in many reports including our studies.
Preliminary screening for antiviral AIDS drugs was carried out using three different in vitro assay systems. Among 104 samples tested, six were found to inhibit the growth of HIV in vitro. Four of six were acidic polysaccharides of sea weed origin and one was a well-known anti HIV chemical whose anti-HIV activity has not been reported.
To investigate the relative frequency of individual human rotavirus serotypes prevailing in Japan, 562 stool specimens collected from patients with rotavirus gastroenteritis between November 1986 and March 1988 in seven districts were examined by an enzyme-linked immunosorbent assay (ELISA) with serotype 1-, 2-, 3-, and 4-specific monoclonal antibodies. Serotype 1 was the predominant serotype in the winter of 1986-1987; however, both serotypes 1 and 2 were detected frequently in the winter of 1987-1988. The results showed the relative frequency of individual serotypes by locale and the yearly change in the prevalence of each serotype in the same area. The result of subgroup specificity of rotavirus obtained by using ELISA with subgroup I- and II-specific monoclonal antibodies confirmed the general finding that rotavirus strains having subgroup I specificity are serotype 2 and those having subgroup II specificity are either serotype 1, 3, or 4. Unusual strains having both subgroup I and II specificity or neither specificity and strains presumed to represent new serotypes were also found.
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A total of 6346 swine sera collected at an abattoir in the city of Obihiro, Hokkaido during the years 1978-87 were tested for the presence of antibodies to swine and human influenza viruses. A high incidence of antibody to A/New Jersey/8/76 (swine type H1N1) virus was observed throughout the 10 years except for the occasional month and a single long period of 15 months. Antibodies to human H3N2 virus in swine appeared to be related to the epidemics of human influenza which occurred in the study area during the years 1980-3, but unrelated to the epidemics during the years 1984-7. A large number of swine were found to be antibody positive to a human H1N1 virus during the period April to June 1964, and a smaller number, during the period November 1986 to June 1987. Both were in relation to human influenza epidemics. However, there were long periods where human H1N1 antibodies in swine could not be found.
We recently developed a method for serotyping human rotavirus (HRV) by an enzyme-linked immunosorbent assay with HRV serotype-specific neutralizing monoclonal antibodies (ELISA serotyping). In the present study this method was compared with the fluorescent focus neutralization test with serotype-specific rabbit antisera (NT serotyping) in the sensitivity and specificity of the test. Direct serotyping of HRVs which were contained in stool specimens indicated that while only 37% of the samples were successfully serotyped in NT, 78% of the samples could be serotyped in ELISA. Regarding the samples whose serotype could be determined in the two tests, the assigned serotypes were identical in both tests. The results obtained indicated the utility of ELISA serotyping in clinical and epidemiologic studies of HRV infection.
With a view to clarifying the actual state of inapparent infection of tsutsugamushi diseases, inhibitants of endemic and nonendemic areas were screened for anti-Rickettsia tsutsugamushi antibody (anti-Rt antibody) by the indirect immunofluorescence test. The anti-Rt antibody-positive rate in the inhabitants of the endemic area (about 50%) was statistically significantly higher than that in the nonendemic area (14.7%). The antibody titer in the inhabitants of the endemic area was 10-160, and the number of inhibitants showing a high antibody titer was 2-4 times larger than that of the nonendemic area. A total of 257 volunteers in the endemic area were analyzed for the changes in anti-Rt antibody titer over 1.5-2 years on an individual basis. An increase in the antibody titer was found in 20 inhabitants. There was no difference in the anti-Rt antibody-positive rate between male and female in either the endemic or the nonendemic area. The positive rate was also compared as to the distribution by 10 years of age. In the endemic area, there were no significant differences in the positive rate between any pair of 10-year age groups from 30s to 60s, whereas in the nonendemic area, the positive rate in the teen-age group was significantly lower than those in the age groups of 20 years or older. In Yamada district, the numbers of serum samples obtained from each age group were about the same, and the distribution of the positive rates showed a normal distribution. The nurse students having their homes in Toyama Prefecture were plotted on the map as for their anti-Rt antibody and geographical distribution. The results showed that many of them having homes in the endemic area were positive for the antibody, while some antibody-positives were scattered all over Toyama Prefecture.
This is a clinical and laboratory report on 98 patients with acute viral conjunctivitis who were referred to the Eye Clinic of the Escola Paulista de Medicina of Sao Paulo, Brazil, from February 1983 to February 1984. It was planned with the objective of confirming the importance of adenovirus and enterovirus 70 as etiological agents of viral conjunctivitis. The occurrence of an outbreak of acute hemorrhagic conjunctivitis during the summer of 1984 permitted a better study of enterovirus 70. In addition, we could demonstrate that sporadic cases, from March to July 1983, were caused by the same virus. This fact confirmed the idea that the spread of the disease was not related to the recent arrival of the virus in the community, but to weather conditions of heat and high humidity.
A total of 571 swine sera collected at an abattoir in the city of Obihiro, Hokkaido during the period February-November 1984 were tested for antibody against human (H1N1) influenza virus strains. A high prevalence of antibody was observed for only 3 months from April to June in that year, in 81/180 sera (45.0%) to A/USSR/92/77 strain and in 50/180 sera (27.8%) to a current epidemic strain (A/Hokkaido/1/84). Some cross-reactions were observed between the A/USSR/92/77 and A/Hokkaido/1/84 antibodies (r = 0.75). Only minor relationships were noted between the A/New Jersey/8/76 (swine type H1N1) and A/USSR/92/77 (r = 0.35) or A/Hokkaido/1/84 (r = 0.51) antibodies. Absorption of sera positive for antibody to the A/Hokkaido/1/84 strain with the homologous virus strain removed all detectable antibodies, while the absorption of the sera with the A/New Jersey/8/76 strain produced incomplete absorption in one half of the sera tested. These results strongly suggest that the swine became infected with a human H1N1 virus as piglets during an epidemic of influenza which occurred in the human population during January and February 1984.
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Influenza viruses concentrated and adsorbed onto nitrocellulose membrane filters by filtration are detected rapidly and sensitively by sequential incubation with the primary antibody and the secondary antibody conjugated with peroxidase. The bound enzyme is detected by incubation with a substrate which is converted to an insoluble colored product. A dual-wavelength TLC scanner is used for densitometric quantitation. The membrane filtration-blotting enzyme immunoassay provides a method for quantitative analysis and rapid typing of influenza isolates. The method may be also applicable for quantitative detection of influenza viruses in throat swab specimens from patients, as well as in tissue culture fluids.
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Anti-thyroglobulin antibody forming cells (AFC) were generated from the cultured peripheral lymphocytes of patients with chronic thyroiditis. In order to clarify whether this reflects the antibody formation in vivo, the number of antibody forming cells generated in the culture was related to the serum antibody titer in 121 cases. There was no case which produced more than 10 AFC from 2 x 10(5) B-cells in the group with the low serum antibody titer (less than 10(2)), while 29.4% produced more than 10 AFC in the patients with antibody titer of 20(2) and 20(4) and 65.2% in the group with titer of 80(2) approximately 640(2). The average number of AFC of the last group was 31.4 +/- 17.7 (SD). AFC and serum antibody titers were estimated on various occasions with the same patients. A good relationship was observed between these two parameters. There was no significant correlation between the numbers of AFC and serum antimicrosome antibody titers.
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