Biomedical subjects
Publications and source records attributed to T Suto.
Six measles virus strains were isolated from clinical specimens. They differed from a prototype strain in being incapable to grow in cell lines derived from monkey kidney and having a slower electrophoretic mobility of the hemagglutinin protein and a very low hemagglutination activity.
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Of the sera which were positive to Rickettsia tsutsugamushi by indirect immunoperoxidase test, approximately 80% sera were positive to a Proteus OXK antigen by Weil-Felix test at 10 or more days after the onset of fever, while only 10% sera were positive within 9 days from the onset of fever. In ELISA using the OXK antigen, almost all of the paired sera of tsutsugamushi disease (TD) patients increased on the IgM antibody titres with the rise of their titres by Weil-Felix test, whereas the IgG antibody titres of these sera were unrelated with the titres of Weil-Felix test. We suspect that the reactivity of TD patients sera to the OXK antigen in Weil-Felix test was derived from the reactivity of the IgM antibody against the OXK antigen common with R. tsutsugamushi. The patient sera infected with a Japanese isolate of spotted fever group rickettsia (SFGR) cross-reacted with the Thai Tick Typhus (TTT) strain of SFGR by indirect immunoperoxidase test. In Weil-Felix test, the reactivity of these sera to OX2 antigen were higher than that to OX19 antigen, like the sera infected with other SFGR, except of R. rickettsii. These sera also reacted with TTT and OX2 antigens by ELISA. The titres of IgM antibody against OX2 antigen in the sera in ELISA were in parallel with the titres of the sera against OX2 antigen in Weil-Felix test, but not the titres of IgG antibody. We suggest that the reactivity of the patient sera infected with SFGR to OX2 antigen of Weil-Felix test is dependent on the IgM antibody.
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Rickettsia was isolated from a patient with Japanese spotted fever, and its proliferation in cultured green monkey kidney cells was observed by electron microscopy. In the course of this study, we observed fusion of infected cells to uninfected cells which may be a way of spreading the rickettsiae from a cell to another. On the other hand, whirlpool-like, multilayer membranous structures, similar to the mesosomes of gram-negative bacteria, were sometimes seen in the rickettsial cells. The other profiles common to the other rickettsiae in spotted fever group were observed, such as the electron-lucent halo zone around the rickettsiae, and external fibrous materials on their surface, but intranuclear multiplication was rarely observed.
An accurate diagnosis of Tsutsugamushi disease (TD) can be made within a few hours after receiving serum specimens by detecting the specific IgG and IgM antibodies in the patient's serum. Using the indirect immunoperoxidase test we found a total of 730 cases of TD in 32 out of 47 prefectures when serum samples from 2,224 cases of suspected disease or fever of unknown origin or from patients with febrile exanthema of unknown cause were examined during a 10 years period (from May 1980 till December 1989). In addition, 27 cases of spotted fever group rickettsial infection were confirmed and one case of African spotted fever group infection was also detected in 1988. Furthermore, possibly the first case of TD was found in People's Republic of Congo (Africa) in 1989.
Immunological analyses of lipopolysaccharides (LPS) isolated from Proteus strains OX2, OX19, and OXK used as antigens of Weil-Felix (WF) test, were performed by quantitative agglutination, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. Antisera against LPS and whole cells (WC) of the three Proteus strains reacted with homologous LPS but not with heterologous LPS, and the reaction was inhibited by the O-polysaccharide fraction isolated from the homologous LPS except OX19-LPS, which lacked O-polysaccharide moiety. The immunological data support the findings that the O-polysaccharide moieties of LPS from OX2 and OXK strains possess different chemical composition (Mizushiri, Amano, Fujii, Fukushi, and Watanabe, Microbiol. Immunol. 34: 121-133, 1990). Antisera against Proteus strains reacted weakly with WC of Rickettsia prowazekii, Rickettsia typhi, and Rickettsia tsutsugamushi. Antisera from patients with tsutsugamushi disease reacted with OXK-WC by WF test when the sera were obtained 13 days after onset of fever. The immunoperoxidase (IP) test titers of these antisera began to rise 6 days after the onset of fever. By ELISA tests these antisera reacted with OXK-WC and OXK-LPS independently of the titers of WF or IP tests.
To clarify the influence of Transcatheter Arterial Embolization (TAE) on the stomach, endoscopic examination was carried out before and after TAE. Forty-six TAE were performed in 27 patients with primary hepatoma. New gastric lesions, erosions and ulcers, were developed in 25 of 46 TAE. There was no significant relationship between the incidence of the lesions in the cases with esophageal varices (15/24) and the cases without (10/22) and there was no significant relationship between the incidence of the lesions after the first TAE (12/22) and after the second TAE (5/14). Period between the first and the second TAE had no statistical influence on the lesions after the second TAE. Hepatic functions (Child's classification; Rmax, K, R15 of ICG; serum total protein; serum albumin; total bilirubin; prothrombin time; hepaplastin test) before TAE were not statistically related to the appearance of the gastric lesions following TAE (Table 1). On the other hand, the cases which showed apparent effects of TAE including 0.2 time decrease of AFP had the more gastric lesions (P less than 0.05) (Table 2). The cases with upper abdominal pain after TAE had more gastric lesions (24/38) than the cases without (2/8) (P less than 0.05). But the cases undergone TAE with high possibility of the influx of gelatin sponge pieces, lipiodol or anticancer agents into the supplying vessels for the stomach did not exhibit significant incidence of the lesions (Table 3). Thus, when TAE is followed by a 0.2 time decrease in AFP, it is necessary to pay more attention to the gastric lesions. The prophylactic administration of H2 antagonist before or just after TAE did not seem useful to prevent the gastric lesions. These findings suggest that the influx of gelatin sponge pieces, lipiodol or anticancer agents to the stomach does not always cause gastric ulcer or erosion.
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A 45-year-old Japanese man developed a black eschar skin lesion and on the body, a number of erythematous seropapules 2 weeks after his return from South Africa. Within 24 h of treatment with minocycline he was afebrile and symptomatically much improved. Serological tests showed increased antibody titres to spotted fever group rickettsiae (SFGR). From the clinical and serological findings we consider this patient to be the first in Japan to have been infected with SFGR in Africa.
The in vitro susceptibilities to five chemotherapeutic agents against a rickettsial strain which was isolated from a case of Japanese spotted fever were determined by cell culture system. Minocycline was the most effective (MIC, 0.15 micrograms/ml) followed by Tetracycline and Demethylchlor tetracycline (0.31 micrograms/ml 0.16 micrograms/ml). Chloramphenicol was less effective (5 micrograms/ml) and Aminobenzyl-penicillin was not effective with the MIC of 10 micrograms/ml or less. Thus, the earlier administration of Minocycline is recommended to clinically suspicious cases of Japanese spotted fever as well as Tsutsugamushi disease.
The reactivity of sera from patients of Tsutsugamushi disease (scrub typhus) with the antigenic polypeptides of Rickettsia tsutsugamushi was analyzed by the immunoblotting method. The reactivity varied greatly among the sera of individual patients tested. IgG and IgM antibodies of most patients reacted with the 54-56 kilodalton (54-56K) polypeptide located on the rickettsial surface, suggesting that this polypeptide is a predominant antigen in the infection. Other polypeptides of 60K, 50-52K, 46-47K, 35K, and 21-25K were reactive with some but not all sera. From the reactivity of these polypeptides, it was suggested that the 54-56K polypeptide is both strain-specific and group-specific, the 60K polypeptide is group-specific, and the 35K and 21-25K polypeptides are subgroup-specific. IgG antibodies seem to be more cross-reactive with polypeptides of multiple strains than IgM antibodies and have a tendency of increased cross-reactivity that was observed in the sera obtained at the later stage of illness.
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Recently developed monoclonal antibodies against the 42,000-dalton major inner capsid protein were used in an enzyme immunoassay to subgroup a total of 156 rotavirus specimens obtained from Japanese infants and young children with acute gastroenteritis during the period between December 1981 and April 1983. Only 2 specimens (1.3%) were identified as subgroup 1, whereas 154 specimens (98.7%) were identified as subgroup 2. The percentage of subgroup 2 rotaviruses obtained in this study was the highest among similar studies thus far performed in different areas of the world. One of the subgroup 1 isolates had fast-moving 10th and 11th gene segments (the "long" pattern) typical of the subgroup 2 human rotaviruses.
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Rotavirus group-specific (common in human rotaviruses) and subgroup 1-specific monoclonal antibodies were established and an enzyme immunoassay was developed for subgrouping human rotaviruses.