The Kitasato archives of experimental medicine最新文献

Salmonella typhimurium is an important causative agent of acute gastroenteritis (food poisoning), and the decision of the source of infection urgently requires epidemiological investigation. There are two types of S. typhimurium, O5-antigen-carrier type (O5(+)-antigen type) and noncarrier type (Copenhagen antigen type). On the assumption that serological differentiation of the types is effective for epidemiological exploration for the source of infection, we produced a monoclonal antibody, TMY1, specific for the O5-antigen. We classified S. typhimurium identified as the causative agent of mass outbreaks of acute Salmonella gastroenteritis according to the O5-antigen type, by using the TMY1. As a result, the bacterium in each outbreak was classified as the O5(+)-antigen type or the Copenhagen antigen type based on the difference in reactivity with TMY1. S. typhimurium isolated from calves in mass outbreaks of diarrhea and from animals with various diseases were also classified by TMY1 according to the O5-antigen type, and TMY1 was found to be as useful as in human cases. From this confirmation, TMY1 was demonstrated to be useful as a marker for epidemiological investigation of the source of infection by the O5-antigen type of S. typhimurium.

We developed enzyme linked immunosorbent assay (ELISA) for the detection of rubella virus antigen, using two monoclonal antibodies, MC-7 and MC-22. The double antibody sandwich ELISA method was carefully standardized and found to be sensitive enough to detect as small as 2.5 ng protein of rubella virus. The infective titers by the double antibody sandwich ELISA closely related to those judged by interference of vesicular stomatitis virus in RK-13 cells. The method is simple, sensitive, and readily applicable to the detection of rubella virus.

Aflatoxins become an economical problem in our country due to its contamination in agricultural commodities for export. The toxin may also cause hepatoma and liver diseases in the Thais as well. It is, therefore, necessary to search for and to develop efficient technology to combat and control such dangerous mold and mycotoxins. This paper is a collection of our previous and present studies towards reduction of risk from aflatoxins in foods and feedstuffs. The investigation of mold and aflatoxin contamination in local foods and feedstuffs in Chiang Mai area was made. The inhibitory effect of garlic extract on growth of Aspergillus flavus and its aflatoxin production was demonstrated. Detoxification of aflatoxins by chemicals such as ammonium carbonate, ammonium bicarbonate and ammonium benzoate was also shown. Preventions of toxigenic mold growth and its aflatoxin production by means of some food preservative were reported. Modifications of such effective chemicals were investigated for safety in future application.

By means of NED-affinity column chromatography, two distinct protein kinases have been selectively purified from the crude membrane extract of mouse brain. One (designated P-I kinase) was eluted from the column by the buffer containing 5 mM EGTA and the other (designated P-II kinase) was eluted by the buffer containing 0.6 M KCl. The activity of A-kinase was detected in the column passed through fraction. Biochemical characteristics of P-I and P-II kinases corresponded exactly to those of C-kinase and casein kinase II (CK-II), respectively. In addition, immunoprecipitate experiment using anti-CK-II antiserum against the beta-subunit of Drosophila CK-II showed that P-II kinase is identical to CK-II and the 62 kDa cellular polypeptide is associated with the kinase.

We have developed a fluorescence microphotometry system for microanalysis of the quantitative distribution of neurotransmitters and their related chemical substances in the brain slice. In the present study, the extensive distributions of cholinergic systems were analyzed quantitatively and in detail throughout the rat whole brains by this novel method through immunohistochemical staining of choline acetyltransferase (CAT). The rat whole brain was slice coronally and continuously, and 50 slices were chosen at approximately 500 microns intervals and stained immunohistochemically for CAT. Immunohistochemical fluorescence intensities were measured through a 6 microns phi (on the slice) pinhole of a microscope, the brain slice was moved along the X- or Y-axes stepwise at 40 microns intervals under the objective lens of the microscope, and the distributions of fluorescence intensities were analyzed over the entire surface of the slice. The brain was divided into approximately 5,000,000 areas, and immunohistochemical fluorescence intensities of those areas were quantitatively measured. The obtained fluorescence intensities of CAT were classified into 8 ranks and were indicated by color coding and by three-dimensional graphics. Also, the actual fluorescence intensity values in large brain regions were presented. This type of brain atlas of the neurotransmitter or its related chemical substances provides very important information on their dynamics in the brain under experimental as well as pathological conditions. Also, this quantitative and detailed analysis is useful for combining morphological data with those from neurochemical and behavioral analyses of brain function.

In order to determine effects of iron deficiency on the living body, rats were given the iron deficient diet (Group 1, iron content, 0.32mg/100g), the complete diet added with iron (Group 5, iron content, 32.5mg/100g), the diet added with 1% chlorella (Group 2, iron content, 2.2mg/100g), the diet added with 5% chlorella (Group 3, iron content, 7.4mg/100g), or the diet added with 10% chlorella (Group 4, iron content, 13.9mg/100g). For the first 30 days, rats of all groups were given the iron deficiency diet to make them iron deficient, and were subsequently given the respective diet during the next 30 days to observe various changes in the conditions of rats. Following results were obtained. 1) When rats were reared for 30 days with the iron deficient diet, rats of these groups became anemic and their hemoglobin concentrations and hematocrit values lowered. Rats of Groups 3, 4 and 5 fed with the diets containing certain amounts of iron rapidly recovered, while the recovery of those of Group 2 fed with less iron content diet was delayed. Group 1 fed with the iron deficient diet showed no recovery. 2) Examination of effects of these diets on the rats body weight gains revealed that the growth of Groups 1 and 2 with iron deficiency was delayed notably (p less than 0.01) as compared with Group 5 and that of Group 3 was likewise restrained (p less than 0.05). The relative organ weights of all rats were examined. The liver weight in Groups 1, 2, 3, 4 was lower than that in Group 5, while that of the spleen in Groups 1 and 2 was higher than that in Group 5. 3) The Numbers of erythrocyte decreased in Groups 1 and 2 (p less than 0.01) and increased in Groups 3 and 4 (p less than 0.01) as compared with Group 5. There was no direct relation between the iron content in the diet and the number of leukocytes and their compositions. 4) Serum iron decreased remarkably in Groups 1 and 2 (p less than 0.01) but there were no intergroup differences in blood glucose value. 5) When osmotic fragility of erythrocyte membranes was expressed in term of NaCl concentration to indicate 50% hemolysis, Groups 1, 2 and 3 apparently increased their resistance as compared with Group 5 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of selenium and vitamin E on lipid level in the blood serum, on the oxygen free radicals generation and on morphology of heart was tested after separate and combined administration to mongrel male rabbits fed on a high-fat diet (HFD). The lipid level and oxygen free radical generation was depressed markedly in animals fed on a HFD and receiving simultaneously selenium and vitamin E. In animals on a HFD the walls of the heart vessels were thickened, always to their complete obliteration. The presence of lipid droplets in endocardium could be observed as well. The hearts of the rabbits receiving selenium showed markedly fewer atheromatously changed vessels. Moreover, no accumulation of lipid droplets was seen in the endocardium of these animals. The least atherosclerotic alterations were observed in the myocardium of rabbits given HFD with addition of selenium and vitamin E in combination, no accumulation of lipids was shown in endocardium of these rabbits. An important finding of this study is, that the combination of selenium and vitamin E results in an intensified protective effect against changes evoked in the heart muscle of rabbits fed on a HFD.

The influence of phagocytic activity on the early stage defence mechanisms in zinc deficient mice was studied using active oxygen production as a parameter and the results obtained were as follows: 1. The body weight of the zinc deficient mice was decreased significantly compared with that of the normal mice. 2. Zinc levels in the liver and blood of the zinc deficient group showed low comparing with the zinc adequate and the control groups (P less than 0.01). 3. The numbers of intraperitoneal (i.p.) cells, which play a leading role in early stage defense mechanisms, showed lower levels in the zinc deficient mice than that of the normal mice. 4. Phagocytic activity was measured as active oxygen production and this activity was found to be impaired in zinc deficient mice. 5. After the typing of i.p. cells and blood cells, it was proved that lymphocyte (lym.) was the main cell (68.5% and 73.8%) in i.p. cells and blood cells of the zinc deficient mice. The control group (non-treated mice) and the zinc adequate group showed a similar pattern of these zinc deficient mice.