Japanese journal of medical science & biology最新文献

Sixty-five haplo-identical living-related renal transplant pairs were subjected to comparative studies for HLA class-I typing suitability between the DNA and serological methods. Our HLA-A genotyping method was highly resolutive and allowed assigning 33 serologically blank specificities and subdividing some HLA-A serological specificities, of which A2 discrimination was considered to be indispensable for the matching analysis because of its high frequency among Japanese. Our HLA-B genotyping method made it possible to identify the 17 serologically blank specificities despite their "low resolutive" capacities. Analysis of 14 DRB1-compatible pairs suggested that HLA-A and -B compatibilities had beneficial effects on the long term graft survival. It was concluded that HLA-A and -B should be genotyped for the matching analysis of the kidney transplant pairs to obtain satisfactory graft outcome.

An electron microscopic study has been carried out to describe the transformation of the miracidium of S. mansoni into the mother sporocysts in the susceptible B. glabrata and the associated host-parasite interactions. The miracidium enters the snail host without morphological alterations. Within 3 hr after entering, all the ciliary epidermal plates of the miracidium are discarded. A new tegument is quickly formed by 5 hr postinfection by the expansion of epidermal ridges. The rapid formation of the new tegument reflects the participation of membrane-bound vesicles in the ridge cytons. The membranes of these vesicles become the new tegument membranes with the discharge of their electron-dense contents into the snail tissues. The vesicular contents discharged into the tissues apparently prevent snail amoebocytes (phagocytes) from attachment to the parasite tegument and thus prevent their interference with the further development of the postmiracidium. If a postmiracidium fails to mobilize membrane-bound vesicles in the formation of tegument, the parasite becomes surrounded by closely attached concentric layers of fibroblasts formed by amoebocytes and histiocytes within 24 hr. The membrane-bound vesicles are present in small numbers in the ridge cytons of the miracidium and become numerous in the postmiracidium stage and with many migrate to the ridges through connecting bridges within 24 hr. By 3 days postinfection when extensive microvilli have formed on the tegument the vesicles have disappeared and are replaced by mitochondria, ribosomes and complex carbohydrate particles. Many fibroblasts in the snail connective tissues have phagocytic capacities and are regarded as snail tissue histiocytes or fixed amoebocytes that eventually may become hypertrophic and detached.

The hematological parameters were assayed in Plasmodium vivax patients with only one infection, two infections, three infections and more than three malarial infections during a period of six months. A steady fall in the levels of hemoglobin as well as packed cell volume (PVC) level was observed with increasing number of infections. The malarial patients showed a progressive decrease in RBC level with increasing number of attacks. The decrease in the hematological indices was statistically significant at all levels of parasitemia. There was a marked increase in the osmotic fragility of the malarial erythrocytes when compared to that of controls. During repeated malarial attacks, significant decrease in MCH (p < 0.05) and MCH (p < 0.01) and increase in the MCV level (p < 0.05) and Heinz body formation (p < 0.001) were observed. Parasite density significantly influenced the fragility of the erythrocytes, Heinz body formation, MCV, MCH and MCHC levels. Thus, the erythrocytes of the patients repeatedly infected with Plasmodium vivax parasite are subjected to structural and functional impairment, ultimately culminating in anemia.

This work focuses mainly on the effect of NaCl along with other mono and divalent anions and cations at pH 4 on survival and virulence properties of Aeromonas hydrophila. To find the optimum stress condition, effects of several other physical factors on NaCl induction were also assayed. A. hydrophila collected from International Center for Diarrheal Disease Research, Bangladesh (ICDDR,B) was found to be more sensitive to pH 4.0 when grown in media containing 200 mM or more salt. Induction of acid sensitivity was rapidly gained in NaCl-supplemented broth at 37 C. There was only slight sensitization after 5 min, but a marked effect was observed within 30 min. Uninduced A. hydrophila gave an average of 40% survival after exposure to pH 4.0 for 5 min. However, NaCl-induced cells of this organism reduced the survival to a great extent having an average of 0.06%. Either increase in salt concentration (100 mM through 400 mM) or decrease (50 mM) resulted in decrease in percent survival when exposed to gradually increased concentrations of salt. The most effective dose for induction was 400 mM NaCl salt. NaCl-induction was found to be more pronounced in log-phase organisms. All other monovalent and divalent anions and cations tested were almost as effective as NaCl except KCl.

We succeeded in hyperproduction of Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (PIPLC), using a Bacillus brevis 47 expression system. The recombinant B. thuringiensis PIPLC was expressed under the control of the middle wall protein gene promoter in B. brevis expression vector pNU211. A large amount of recombinant PIPLC (0.4 g per liter culture) was secreted into the medium as a mature enzyme, and the enzymatic properties of purified recombinant PIPLC were similar to those of the enzyme from wild-type B. thuringiensis. This system provides a useful approach to the three-dimensional structure-function relationship of PIPLC.

In order to understand the epidemic trends of influenza virus infection in Taiwan, 5,882 throat-swab specimens were collected from June 1979 to June 1995. Influenza virus was detected in 313 specimens including samples collected at Taichung and Tainan from 1981 to 1982. Among them, 214 isolates (68.4%) were identified as influenza virus type A, and 99 (31.6%) as type B. In the course of the surveillance, the influenza virus strain A/Taiwan 1/86 (H1N1), known as a world-wide reference strain, was isolated in April 1986. Influenza virus infection was identified throughout the year in Taiwan based on the frequency of detection of the virus. Some strains were referred to as intermediate strains in comparison with the reference strains on the basis of antigenic heterogeneity. About 80% of the isolates identified in this laboratory were from children under 12 years old. The rate of isolation of virus was about 46% during the epidemic season.

A serosurvey for Pneumocystis carinii infection of laboratory-bred and wild-born monkeys was made by the indirect immunofluorescence method. The antibody titers of wild cynomolgus (Macaca fascicularis) and Japanese monkeys (Macaca fuscata fuscata) to P. carinii (Pc) were higher than those of laboratory-bred cynomolgus monkeys; 54.9% of the wild cynomolgus and 40% of Japanese monkeys had antibody titers higher than 1:40, although only 9.4% of the laboratory-bred cynomolgus monkeys did so. Pc cysts in the lungs were examined in the laboratory-bred cynomolgus monkeys by using toluidine blue O stain, and the number of cysts in the lung was small, when compared with those in the lungs of SIV-infected monkeys showing severe pneumosystosis. The results obtained from the studies suggested the possibility that P. carinii infection was more widely epidemic in the wild-born monkeys than in laboratory-bred monkeys.

We titrated human cytomegalovirus (HCMV) DNA in urine specimens obtained from 14 healthy individuals and a renal transplant patient with HCMV pneumonitis by modifying the method for titration of varicella-zoster virus DNA previously described (1,2). Of 14 HCMV seropositive healthy individuals, 13 had HCMV DNA under the detection limit of 10(2.0) copies/ml, whereas one person had 10(2.0) copies/ml. The viral DNA in urine samples was at a low level in healthy individuals with latent infection. In a case with HCMV pneumonitis after renal transplantation, the amount of HCMV DNA in urine gradually increased from the level under 10(2.0) copies/ml and reached a peak of 10(4.7) copies/ml one month prior to the manifestation of pneumonitis. It, thereafter, decreased with the course of clinical remission, and finally settled at under 10(2.0) copies/ml. Serial titrations of HCMV DNA in urine specimens proved to be useful in identifying recipients at risk of developing active HCMV infection after renal transplantation and as a guide for treatment of patients.

The most common type of gastric carcinoma, namely the intestinal type, has been proposed to result from a precancerous process in which chronic gastritis, atrophy, intestinal metaplasia and dysplasia develop in a sequential manner. Helicobacter pylori is considered as the main cause of chronic atrophic gastritis and thus may play a role in the gastric carcinogenesis process. The present study was aimed at investigating the prevalence of H. pylori in the gastric carcinoma cases. Urease tests and ELISA developed in our laboratory and culture were used to assess the prevalence of H. pylori in the study group. The positivity of H. pylori by various tests ranged from 56.0 to 62.6% in the gastric carcinoma group and 37.3 to 46.6% in the control subjects, the difference being statistically significant. This suggests that H. pylori infection could be associated with an increased risk for gastric carcinoma, but only a very small percentage of the infected persons develops gastric carcinoma. Therefore, it is suggested that along with other critical risk factors, H. pylori may act as a cofactor in the pathogenesis of gastric carcinoma.