The Kitasato archives of experimental medicine最新文献

The reproductive behavior of the stickleback is unique and odd, occurring inevitably with nesting. However, upon investigation, it has been found that nesting is an obstacle to hatching. The author conducted a survey in the necessity of nesting behavior in the nine-spined stickleback, Pungitius pungitius, and reached following conclusion: For Pungitius pungitius, nesting is the means of communicating to descendants settlement at a fixed area where cold water flowed bountifully and the water temperature was constant. Pungitius pungitius has evolved a behavior pattern that involves settling where water temperature is uniform, without evolving physiologically or morphologically, thereby enabling Pungitius pungitius to adapt to the changes in environment.

We examined the ascites-form of the murine testicular teratocarcinoma (402AX) as an animal model of spontaneous metastasis. We inoculated 2 x 10(5) cells into a total of seven hundred and twenty-seven 129/J strain mice. They showed clinically manifested ascites approximately two weeks later and died three to nine weeks later. Metastases were seen in lungs and hilar lymph nodes two to three weeks later. We performed staging and developed a definition of metastasis. Pulmonary metastases were quantified by mapping and counting the number of metastatic nodules in the lungs. Lymph node metastases were quantified by measuring the maximum diameter of metastatic lymph nodes (tumors). Additional sectioning was shown to be beneficial to demonstrate lymph node metastasis. The macroscopical metastatic rate was much less than the microscopical metastatic rate. The metastatic rate of the natural-death mice was much higher than that of the sacrificed mice. Lymph node metastatic rate was much higher than pulmonary metastatic rate. The metastatic rate had a direct relationship with the volume of ascites. This animal model can be used to study spontaneous metastasis.

Although the role of metallothionein (MT) has been suggested by many researchers, the exact biological or physiological roles of MT are still unclear. Up to the present, the role of this ubiquitous low molecular weight protein has variously been reported as 1) the regulation of the normal absorption and homeostasis of essential metals such as zinc (Zn), copper (Cu), 2) the chelation and detoxification of toxic metals such as cadmium (Cd) or mercury (Hg). The mechanisms of Cd uptake from gastrointestinal lumen and its consecutive transport from the intestinal mucosa into blood circulation and tissue are not well known. The chemical form of Cd is an important factor on its gastrointestinal absorption. It has been reported that Cd in foods such as meat, seafoods, and vegetable is existing mainly as Cd-MT or MT-like Cd binding proteins. Also it is well known that MT is induced in the intestinal tissue by oral Cd administration. Until today, the mechanism of gastrointestinal absorption has been mainly discussed about Cd ion. However, it needs the consideration including the chemical form of Cd such as Cd-MT in foods or Cd bound by MT induced in the intestinal tissue. Namely, it is important to assess the possible role of MT on gastrointestinal absorption and its consecutive tissue distribution of Cd.

Thiotetromycin is isolated from Streptomyces sp. OM-674 discovered in the course of the screening for antibacterial antibiotics. The antibiotic was found to be a specific inhibitor of type II fatty acid synthase. In order to search acyl-CoA synthetase inhibitors, a kind of yeast, Candida lipolytica, was utilized as test organism for the primary screening. Four structurally related compounds named triacsin were isolated from Streptomyces sp. SK-1894 as a specific inhibitor of acyl-CoA synthetase I of C. lipolytica. Further biochemical studies revealed that triacsins inhibit acyl-CoA synthetases from widely different sources. The inhibition is competitive with respect to long chain fatty acids. The common N-hydroxytriazene moiety of triacsins is essential for inhibition. To discover inhibitors of mevalonate biosynthesis, Vero cells were used as test organism for the screening. A beta-lactone 1233A(F-244) isolated from Scopulariopsis sp. F-244 was demonstrated to inhibit mevalonate biosynthesis with assays using cell and enzyme systems. Further studies demonstrated that the compound inhibits 3-hydroxy-3-methylglutaryl (HMG)-CoA synthase specifically and irreversibly. The geometry of the (2R, 3R)-beta-lactone ring in the structure is essential for specific inhibition against the enzyme.

The aim of this study was to investigate the effect of unilateral nephrectomy on the pharmacokinetics of gentamicin. The study was carried out on 19 male rabbits. Gentamicin was injected i.v. at a dose of 3.5 mg/kg twice daily during 5 days, before operation and after 2 weeks as well as 3 months from nephrectomy. Blood for the assays was collected within 6 hours after the drug administration on the 5th day of each study stage. The immunofluorescence polarization method was employed for determination of gentamicin concentration. The one-compartment open model was used for calculations. It was shown that in unilaterally nephrectomized rabbits the elimination of gentamicin can be significantly impaired during the whole study period.

Normal human serum (NHS) contributed to the establishment of cells producing HIV-1 under the conditions of coculture of peripheral mononuclear cells (PMC) from HIV-1 seropositive patients and of PHA-prestimulated or -non-stimulated PMC from seronegative healthy donors. No addition of IL-2 and Polybrene was necessary. Since, in the case 90101, the mitochondrial displacement-loop DNA showed identical sequences in the established cells and the HIV-1 seropositive patient's cells, it can be asserted that the HIV-1-producing cells originated from the patient. These cells are still releasing HIV-1-virion more than one year after their establishment.

Four kinds of small molecular weight haptens, Desmosine, Adriamycin, 4'-carboxycotinine and 5'-Fluorouracil were used as the immunizing antigens to obtain rabbits polyclonal antisera. All of these haptenes were conjugated to Bovine Serum Albumin (BSA) using 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (EDCl) reagent. The functional amino or/and carboxyl group in hapten molecules was utilized for conjugation with BSA by EDCl reagent. The hapten conjugated with BSA was mixed with Freund's Complete or Incomplete Adjuvant, and immunized to rabbits abdominal subcutaneous regions. More than 3 times immunized rabbit's antisera were evaluated the titer, and the specificity was investigated by ELISA method. The specific antisera against desmosine and adriamycin were produced. Anti-desmosine antibodies had no cross-reaction to molecular structure resemble pyridinoline. Anti-adriamycin antibodies reacted well to adriamycin and it could distinguish the differences of -epi type of adriamycin. The ELISA assay systems used here had such sensitivity. However the specificity possessing antisera against 4'-carboxycotinine and 5-Fluorouracil could not produce even though the antisera titers were elevated. The reasons why and what kinds of problems were there are discussed in this paper. For the production of the specific affinity possessing antisera, the length and distance between the carrier protein and the hapten and the shape of the functional groups were the important factors for production of the specific antisera which recognize free form hapten molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

In urethan-anesthetized rats, unitary discharges of wide dynamic range (WDR) neurons were extracellularly recorded from the lumber cord. Repetitive electrical shocks were delivered through needle electrodes in the receptive field with sufficient strength to activate C fibers. The number of evoked discharges was compared before and after application of manual acupuncture to the LI 4 Hegu [symbol: see text] or ST 36 Zusanli [symbol: see text] for 30 seconds. The effects of acupuncture were followed up to 5 minutes after removal of the acupuncture needle. Two different analgesic effects were observed: acupuncture to the LI 4 Hegu resulted in long-lasting inhibition following insertion of the needles and stimulation of the ST36 Zusanli produced short-term and long-lasting inhibition similar to that seen in acupuncture to the LI 4 Hegu.

We have been discussing in connection with a space quarantine. The subject is not merely an academic problem, but it contains a fundamental problem which avoid the contamination of other planets by terrestrial microflora. The space environments in the solar system were simulated by using an apparatus of cryostat (low temperature of 110-310K, high vacuum of 1 x 10(-8) torr) and proton irradiation from the Van de Graaff generator. After exposure to a barrage of protons corresponding to about 250 years in solar space, Tobacco mosaic virus, Bacillus subtilis spore, Staphylococcus aureus. Micrococcusflavus, Clostridium mangenoti spore and Aspergillus niger spore showed considerably high survival rates. Furthermore, it was found firstly that an irradiation of proton induced considerable mutation frequency compared to that of spontaneous and caused also the cytological effects based on a damage of chromosome.