Biomedical subjects
Publications and source records attributed to C Morita.
Immunomagnetic separation (IMS) improved the detection of Coxiella burnetii in cow's milk by the polymerase chain reaction (PCR). IMS represents a novel approach to the isolation of microorganism from milk. The combination of IMS and PCR analysis has an adequate sensitivity for detection of C. burnetii.
To determine predictive factors of response to interferon (IFN) therapy in chronic hepatitis C patients, we administered IFN-alpha, 1 6 million U1 intramuscularly daily for 2 consecutive weeks, then three times a week, to 136 patients judged to have chronic hepatitis C virus (HCV) infection according to HCV-RNA positivity. We also investigated the most effective length of IFN-alpha treatment according to efficacy factors, i.e., histological activity index. HCV-RNA genotype, and HCV-RNA levels. patients were classified either into a short-term group (entire treatment period 16 weeks), standard-term group (24 weeks), and long-term group (40 weeks). Patients were assessed as complete responders (CR) if their HCV-RNA became negative and their alanine aminotransferase (ALT) decreased to < or = 39 IU/L after 18 months of treatment or nonresponders in other cases. Results showed that HCV-RNA levels and genotype were statistically significant predictive factors. CR rates in the standard- and long-term groups were significantly higher than in the short-term group (p < 0.05). In patients with low HAI scores, the long-term group showed the highest CR rate. In patients with low virus counts, the CR rate increased to 73% in the 24th week and 100% in the 40th week. CR rates in patients with HCV-RNA genotype 1b and 2a or 2b also increased as the treatment period became longer. For efficacy, a 24-week treatment period was necessary. In patients with mild liver tissue damage or low virus counts, 40 weeks of treatment proved highly useful.
It was found that Bartonella henselae (B. henselae) may induce clinical disorders in cats in natural conditions from a comparison of the serological status for B. henselae with the serostatus for feline immunodeficiency virus (FIV) and several clinical characteristics in 170 domestic cats. Seropositivity for B. henselae was not significantly different between FIV antibody-positive and -negative cats (18.4% vs 16.0%). The incidence of clinical characteristics were compared among four cat groups distinguished by the reactivity of sera against B. henselae and FIV. The incidence of lymph node swelling was lower in only FIV antibody-positive cats (3.0%), but higher in B. henselae antibody-positive cats (13.6%) and significantly higher in both B. henselae and FIV antibody-positive cats (42.9%) compared with the incidence of lymph node swelling in cats which were negative for both antibodies (5.5%). The same relation was also observed for the incidence of gingivitis among the 4 cat groups, suggesting that coinfection of B. henselae and FIV may be associated with gingivitis and lymphadenopathy in cats.
In Thailand, the first human cases of spotted fever group rickettsiosis were reported in 1994, but no serosurveys on wild rats have yet been conducted. We investigated the seroepidemiology in wild rats collected in the 1970s from two regions in Thailand, and found a 62.2% positive rate of antibodies for spotted fever group rickettsia (SFGR) by the indirect immunofluorescence antibody test. Of the antibody-positive rats, 82.2% had higher titers of antibodies against TT-118 than those against Rickettsia japonica, which suggests that Thailand is infested mainly with the TT-118 strain or its antigenically related organisms. The prevalence of antibodies in Bandicota indica was significantly higher than that in other species, which suggests that B. indica is important as a reservoir of SFGR in Thailand.
The prevalence of Listeria monocytogenes in the environment of dairy farms was surveyed from December 1993 to June 1994 in one city of Hokkaido. L. monocytogenes was isolated from 3 out of 5 farms investigated. Serovar 4b organism was isolated from the brain stem of a cow from one farm which was clinically diagnosed as having listeriosis. The same serovar of L. monocytogenes was also isolated from the rectal contents of a healthy cow, straw on the floor, straw in the barn, and silage scattered around the silo from the same farm. At another farm, with no reported cases of bovine listeriosis, serovar 1/2 organism was isolated from the same types of samples as the above mentioned farm except from straw on the floor. The difference in the isolation rates of the organism from straw on the floor between the two farms (22%:5/23 vs 0%:0/24) is considered to be caused by the different feeding methods of silage between the two farms.
Serum samples from 337 wild house mice (Mus musculus) from 35 sites in China, collected in 1992 and 1993, were examined for antibodies against lymphocytic choriomeningitis virus (LCMV). Ten samples from eight sites were found to contain such antibodies. Six of the eight positive sites were located in the territory of M. m. gansuensis. One of the other two sites was located in the territory of M. m. castaneus in southern China and the other site was in a habitat of M. m. castaneus which had invaded into the western end of the territory of M. m. homourus. It seems likely that LCMV is distributed in the territories of M. m. gansuensis and M. m. castaneus in China. This is the first report of detection of these antibodies in wild house mice in China and specifically in the territories of M. m. gansuensis and M. m. castaneus.
The prevalence of antibody against spotted fever group rickettsia (SFGR) was investigated with Rickettsia japonica antigen in small rodents captured in an area in Hokkaido, where no human cases of SFGR infection had been reported. Antibody against SFGR was found in Apodemus speciosus and Clethrionomys rufocanus but not in Apodemus argenteus. None of these rodents had antibody against R. typhi. This is the first report of the antibody against SFGR in rodents in Hokkaido.
The prevalence of antibodies against Seoul virus was investigated in 655 wild rats (Rattus norvegicus, R. rattus, R. rattus diardii, R. exulans, R. tiomanicus) captured in seven port areas of Indonesia. Twenty-four of 238 R. norvegicus, one of 142 R. rattus and one of 102 R. exulans from two port areas had the antibodies against Seoul virus.
A total of 199 domestic cat serum samples from 3 geographical areas (northeastern, central and southwestern) of Japan collected between 1992 and 1994 were examined for serum antibody against Bartonella henselae using an immunofluorescent assay. The antibody prevalence was 15.1% (30/199). A significant difference in the prevalence of B. henselae antibody was observed between the northeastern area (6.3%:3/48) and the central area (22.0:13/59) in Japan. There was no significant difference between the average age of seropositive cats (4.39 +/- 3.26 years) and that of seronegative cats (4.03 +/- 3.84 years), and also between the frequency of seropositive male cats (16.5%:15/91) and that of seropositive female cats (11.8:9/76). This is the first report of B. henselae antibodies in cats in Japan
Cats are assumed to be one of the most important reservoirs of causative agent of human Q fever especially in urban areas. There is no evidence of Coxiella burnetii infection in cats in Japan prior to this. Sera from 100 cats, collected in various parts of Japan, were examined for antibody against C. burnetii. Sixteen out of the 100 samples contained antibodies against C. burnetii. The prevalence of the antibody decreased from the northeastern to the southwestern part of Japan. A high prevalence of the antibodies was observed in sera from cats of more than four years of age. It is difficult to deny that cats would be one of the important sources of human Q fever in Japan.
Mice found in the port areas in Japan, where antibody to lymphocytic choriomeningitis virus (LCMV) was detected, may have originated or partially originated from a southern Asian subspecies, Mus musculus castaneus.
Two Seoul virus strains were isolated from the same wild brown rat (Rattus norvegicus) by 2 different procedures. While one isolate (TR-352) by means of a cell culture system had no horizontal transmissibility in 3-week-old rats, another isolate (TR-352R) by means of inoculation to newborn rats had transmissibility in rats.
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We evaluated the prevalence of Coxiella burnetii antibodies in 626 human serum samples (275 from veterinarians, 107 from meat-processing workers, 184 from respiratory-disorder patients, and 60 from healthy humans) by the indirect immunofluorescence test. Of the serum samples examined, 54 (8.6%) and 103 (16.5%) reacted positively to phase I and II antigens, respectively, of C. burnetii. The rates differed for healthy humans and respiratory-disorder patients. Antibody prevalence was high for healthy humans living in close contact with animals (e.g., veterinarians and meat-processing workers).
The prevalence of antibodies against hantavirus in 413 rats (Rattus norvegicus) captured in eight regions of the Tokyo Bay area from 1983 to 1992 were examined by the indirect fluorescent antibody test. Antibody-positive rats were found in Tokyo Port in 1983 (34.8%), 1984 (25.9%), 1985 (22.0%) and 1986 (15.6%), in Kasai Seaside Park in 1989 (3.2%) and 1990 (4.2%) and in Chiba Port in 1990 (6.7%). In Tokyo Port, antibody-positive rats were found in any season in 1984 and 1985, and seroprevalences among two age groups, i. e., less than six months and six or more months of age were 18.1% and 28.4%, respectively. Three virus strains were isolated from rats captured on reclaimed land No. 13 in Tokyo Port in 1985 and named TQR-23, TQR-48 and TQR-50. These strains were antigenically identical with other rat strains, e. g., strain SR-11 and TR-352 but were discriminated from 76-118 strain by the neutralization test. Until 1990, persistence of hantavirus among rats inhabiting the Tokyo Bay area was demonstrated and hantavirus may be continuously prevalent in rats in this area.
We present a successfully treated case of a multi-septated massive hepatic cyst with repeated injection of minocycline hydrochloride (MINO). A 57-year-old Japanese female complaining of right back pain, hypochondralgia and hypertension had a multi-septated massive hepatic cyst, 25 cm in diameter. Multiple cysts of various sizes were also seen in liver and kidneys. In order to reduce the size of the massive hepatic cyst to relieve the complaints, we performed the reduction therapy of the cyst. After a pig tail catheter was inserted into the cyst, the cystic fluid was aspirated and then a total of 3900 mg of MINO was injected. Red-brownish, serous cystic fluids were obtained. Cytology and bacterial culture were negative, but the LDH (3, 336 IU/l) and CA19-9 (751,500 U/l) concentrations were very high. After the 9 series of the therapy, the cyst was minified on CT and the patient's symptoms were relieved. Furthermore high blood pressure was improved. Thus, the therapy of size-reduction for a massive hepatic cyst is revealed to be very safe and useful.
In the Kanto area a total of 245 wild rats were captured. All rats captured in Ikebukuro (110 rats) and 9 out of 41 rats in Yokohama were Rattus rattus, and all other 126 rats were Rattus norvegicus. In Kashima and Ikebukuro, listeria was isolated from 28 rats (77.8%) and 27 rats (24.5%), respectively, but in the other 4 areas listeria was isolated from 0-7% rats. Listeria monocytogenes was isolated from 12 rats (10.9%) captured in Ikebukuro and 2 rats in Kashima and Numazu. The frequent isolation of L. monocytogenes in buildings suggests the possibility of R. rattus as a reservoir of L. monocytogenes and the continual environmental contamination in buildings by L. monocytogenes.
A spotted fever group rickettsia was isolated from Apodemus mice captured near the site where a person had been infected in Miyazaki Prefecture. Antigenic characteristics of the isolate designated as strain TO-1 were compared with those of Rickettsia japonica (strain YH) and Rickettsia montana (ATCC VR611) by the indirect fluorescent antibody test with 14 serum specimens obtained from Apodemus speciosus, immune rat antisera against the strains TO-1 and YH, and three patients' sera. The titers of these sera measured with strain TO-1 were identical to those with strain YH, suggesting the antigenic similarity between these two organisms. It was also suggested that Apodemus speciosus is likely to be an important vertebrate host for a spotted fever group rickettsia in Japan.