Japanese journal of medical science & biology最新文献

A rapid survey in Delhi and surrounding areas was undertaken in September 1994, during plague outbreak in District Beed (Maharashtra) and Surat (Gujarat) to monitor rodent/flea population and to determine susceptibility status of fleas to insecticides. The five rodent species in order of their prevalence were Rattus rattus (86.06%), Mus musculus (15.33%), Suncus murinus (2.47%), Bandicoota indica (0.48%) and B. bengalensis (0.48%). Two flea species, Xenopsylla cheopis and X. astia, were captured from these rodents. The absolute flea index was found to be ranging between 0.08 to 4.0 in various localities. X. cheopis and X. astia indexes were ranging between 0.22 to 2.08 and 0.08 to 4.0, respectively. Susceptibility test results with X. cheopis collected and reared in the laboratory revealed that it is resistant to DDT and Dieldrin, tolerant to Malathion and susceptible to K-othrin (Deltamethrin).

Cadmium, a divalent metal toxicant, preferentially localizes in hepatocytes and causes liver injury. DL alpha-lipoic acid is a dithiol which is effective in rendering protection against cadmium-associated liver damage, by virtue of its two sulfhydryl moieties. Lipoate was administered to cadmium-exposed rats which were either prior administered with buthionine sulfoximine to deplete liver glutathione or not. During lipoate treatment, significant protection was rendered against cadmium toxicity even under glutathione-depleted experimental condition. This highlights the antioxidant property of lipoic acid and its efficacy in mitigating cadmium-associated liver assault even in the absence of glutathione synthesis.

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.

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.

MPB64, a secretory protein of Mycobacterium bovis BCG Tokyo, was isolated from a culture filtrate of the bacteria in Sauton synthetic medium harvested on day 8. The protein was isolated by five steps; (i) concentration of the culture filtrate by cutting the molecules smaller than 5 kDa with the Millipore Pellicon Cassette system, (ii) affinity separation by a Phenyl Sepharose CL-4B column, (iii) separation with a DEAE-Sepharose CL-6B column with 3 M urea, (iv) separation with a Sephacryl S200HR column, and (v) separation with a DEAE-Sepharose column without urea. MPB64 in each fraction was determined by comparing the band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with that of standard MPB64. The specificity of isolated MPB64 was tested by immunoblotting with anti-MPB64 antibody. The potency of isolated MPB64 in eliciting skin reaction in the BCG-sensitized guinea pigs was the same to that of standard MPB64. The method described herein is an improved one for isolating MPB64 from a large volume of culture filtrate of M. bovis BCG Tokyo. The technique should be applicable to isolation of other mycobacterial secretory proteins.

A cloned Plasmodium falciparum line was subjected to in vitro drug pressure, by employing a relapse protocol, to select progressively resistant falciparum lines to pyrimethamine and cycloguanil, the two dihydrofolate-reductase (DHFR) inhibitor antimalarial drugs. The falciparum lines resistant to pyrimethamine were selected much faster than those resistant to cycloguanil. In 348 days of selection/cultivation, there was 2,400-fold increase in IC50 value to pyrimethamine, whereas only about 75-fold decrease in sensitivity to cycloguanil was registered in 351 days. Pyrimethamine-resistant parasites acquired a degree of cross resistance to cycloguanil and methotrexate, another DHFR inhibitor, but did not show any cross resistance to some other groups of antimalarial drugs. The highly pyrimethamine-resistant line was not predisposed for faster selection to cycloguanil resistance. Resistance acquired to pyrimethamine was stable. The series of resistant lines obtained form a good material to study the 'evolution' of resistance more meaningfully at molecular level.

We established two cell lines that stably express hemagglutinin-neuraminidase (HeLa-HN) and fusion proteins (HeLa-F) of a fusogenic strain of mumps virus. Infection of HeLa-F cells with a nonfusogenic strain resulted in induction of extensive cell fusion. On the other hand, HeLa-HN cells appeared resistant to cell fusion induced by mumps virus infection.

Interleukin-12 (IL-12) is a heterodimeric cytokine. In order to transduce both cDNAs for p35 and p40 of IL-12 in the tumor cells, a polycistronic retroviral vector was constructed by inserting the internal ribosome entry site gene of encephalomyocarditis virus between two cDNAs. On the other hand, two cDNAs were sequentially transfected in the tumor cells. Both polycistronic gene transfectants and double transfectants produced biologically active mouse IL-12. IL-12-expressing tumor cells were all rejected in syngeneic mice, and induced cytotoxic T lymphocyte activity. The capacity to induce anti-tumor memory may depend on the amount of IL-12 produced by the transfectants, because the relatively higher IL-12 producer tumor cell line induced the anti-tumor memory in the rejected mice, but the lower producer did not.