Biomedical subjects

N Osawa

Publications and source records attributed to N Osawa.

At least 19 recordsLinked to original sources

PubMed1992

Mapping of the nu gene using congenic nude strains and in situ hybridization.

The chromosomal location of the nu gene, which is responsible for hairlessness and athymus, was determined using six DNA markers (interleukin 3 [Il-3], Myhs, Acrb, Evi-2, Mpo, and Hox-2) on mouse chromosome 11. We constructed the high-resolution physical mapping of the six DNA markers on chromosome 11 by in situ hybridization using fluorescence-labeled cosmid probes. The results indicate the order of centromere-(41cM)-Il-3-(3cM)-Myhs- (4cM)-Acrb-(6cM)-Evi-2-(3cM)-Mpo-(5cM)- Hox-2. We have used congenic nude strains and examined which of the six DNA markers were derived from the original nude mouse. We found the Evi-2 locus is linked to the nu gene in all the informative, independent congenic nude strains. From these data, we could estimate the location of the nu gene, not only genetically but also physically within a region that spans approximately 17 megabases (9 cM) between the Acrb and Mpo genes.

Animals↗

PubMed1992

Oxygen-independent antimicrobial activity against Salmonella enteritidis of specially activated macrophage with living vaccine.

Characteristics of peritoneal macrophages recovered from mice infected with two attenuated strains SER and Jena of Salmonella enteritidis were compared. Strong resistance against lethal infection with a virulent strain 116-54 of S. enteritidis was seen in a group of mice immunized with strain SER, but not in a group of mice immunized with strain Jena as well as in a control group. Peritoneal macrophages from mice immunized with strain SER showed an enhanced Salmonella-killing activity, an increased generation of O2- and an increased expression of Ia antigen on 7 to 14 days after infection when compared with those from mice immunized with strain Jena and thioglycollate(TG)-elicited macrophages as a control. The bacterial number of strain Jena in organs decreased more rapidly than that of strain SER after day 4 of infection. These observations suggest that the survival of an attenuated Salmonella bacilli at reticulo-endothelium is essential to increase of their activities of macrophages. Macrophages from mice injected with recombinant interferon(IFN)-gamma for 3 days induced the activated stage of the same characteristics as noted in activated macrophages from mice immunized with strain SER. Effect of oxygen intermediates (OI) scavengers such as superoxide dismutase and catalase on Salmonella-killing activity of activated macrophages was not seen at all. These results suggest that an increased generation of OI may be not primarily responsible for the ability to inhibit the intracellular growth of a virulent strain of S. enteritidis in macrophages activated by immunization with live, attenuated strains and injection with rIFN-gamma.

Animals↗

PubMed1992

[Clinical study of Pseudomonas aeruginosa isolated from the urine of patients with urinary tract infections].

We studied the characteristics of Pseudomonas aeruginosa isolated from the urine specimens of the patients with urinary tract infections (UTI), in the urological unit at Kitasato University Hospital, between April, 1989 and March, 1990. Pseudomonas aeruginosa was detected in 8.0% of the total urine specimens (1.1% from outpatients, 6.9% from inpatients). Serotype of Pseudomonas aeruginosa was F (33%), G (17%), M (14%) and others (36%). In sensitivity tests, imipenem (IPM) had the lowest MIC among 8 antimicrobial agents tested, which were imipenem, piperacillin, cefsulodin, ceftazidime, aztreonam, gentamicin, amikacin, and ofloxacin with 5.0%, 82.0%, 74.0%, 69.0%, 92.0%, 67.0%, 79.0% and 82.0% resistant strains, respectively. Bladder cancer was the most common underlying disease in the urological patients with Pseudomonas infection. Pseudomonas aeruginosa infection is still an annoying problem in UTI among compromised patients suffering from advanced urinary tract malignancies.

Bacteriuria↗

PubMed1991

Possible role of Streptococcus pyogenes in mucocutaneous lymph node syndrome. XII. Variable responses of platelets in MCLS seem to be explainable by streptococcal pyrogenic exotoxin.

As a model system for mucocutaneous lymph node syndrome (MCLS), we have advocated and used mice which had been rendered tolerant to Streptococcus pyogenes-associated antigens by neonatal infection with group A beta-hemolytic streptococci, because these mice have shown a variety of peculiar bioimmunological characteristics bearing a striking resemblance to those of MCLS patients. The results of our current investigations reaffirmed the reliability of the animal model by indicating that mice subjected to neonatal infection with S. pyogenes, or inoculation with streptococcal pyrogenic exotoxin (SPE) in Freund's adjuvant, were perfect counterparts of patients with MCLS on account of their platelet activation and hyperaggregability in response to provocative treatment, which are familiar findings in this disease.

Animals↗

PubMed1991

Possible role of Streptococcus pyogenes in mucocutaneous lymph node syndrome XIII. No recovery of beta-hemolytic streptococci from pharynx of MCLS patients.

Lack of recovery of beta-hemolytic streptococci from the throat of 80 patients finally diagnosed as mucocutaneous lymph node syndrome was again confirmed, although alpha-hemolytic streptococci were consistently isolated from all patients but one. The implications of these findings were discussed, particularly in terms of the possible role of Streptococcus pyogenes in the pathogenesis of this disease.

Bacteria↗

PubMed1991

Use of cycloheximide on intracellular growth of Mycobacterium leprae in cultured murine macrophages.

Mycobacterium leprae is an obligate intracellular parasite and grows within mononuclear phagocytes. When murine macrophages derived from the peritoneal cavities of CBA mice were infected in vitro with M. leprae (Thai-53 strain), intracellular multiplication was observed three weeks after infection. On the other hand, there was no increase in the number of heat-killed M. leprae at the same times after infection. Morphological studies showed that the growth rate of the bacteria increased by about 20-30% in medium supplemented with cycloheximide. With the addition of cycloheximide to the culture medium, metabolic activity of macrophages was decreased but infected cells were maintained in good condition and seldom floated off from the culture flask.

Animals↗

PubMed1991

Intracellular fate of Mycobacterium leprae in cultured murine macrophages in 24-well trays.

Mycobacterium leprae is an obligate intracellular parasite which grows within mononuclear phagocytes. In clinical cases, M. leprae reaches enormous numbers in the macrophage-rich granulomas of leprosy. Peritoneal macrophages from CBA mice were cultured in Waymouth medium containing fresh horse serum in Costar 3424 trays (24 wells, 16 mm in diameter) each containing 9 x 12 mm cover slips. This medium was supplemented with 0.5 micrograms/ml of cycloheximide. These cells were infected with M. leprae Thai-53 strain obtained by nude mice inoculation. Significant multiplication of the acid-fast bacilli in the macrophages was observed three weeks after inoculation. This experiment showed M. leprae mainly multiplied in cells and not by rephagocytization of M. leprae derived from destroyed cells.

Animals↗

PubMed1989

Functional difference in monoamine transmitters in the behaviorally abnormal mouse mutant (wriggle mouse sagami).

A mutant mouse (wriggle mouse sagami, WMS) with neurological disorders was found in a colony of the BALB/c strain. The clinical signs included tremor, dystonia and involuntary movements. The concentrations of the neurotransmitter substances, noradrenaline (NA), dopamine (DA), 5-hydroxytryptamine (5-HT) and acetylcholine (ACh), were measured simultaneously with their metabolites in dissected brain regions by high-performance liquid chromatography with electrochemical detection. The turnover of 5-HT was significantly higher in the cerebral cortex, hippocampus, hypothalamus, midbrain and pons-medulla of WMS than of the genetic control, BALB/c. The intrastriatal DA and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid were increased. However, there was no evidence to suggest an increase in turnover rate of this neurotransmitter. An increase in concentration of and decrease in turnover rate of NA were observed in the cerebellum of this mutant. These findings suggest that multiple disturbance of the neurotransmitter system was largely responsible for the manifestation of the clinical signs of WMS.

Acetylcholine↗

PubMed1989

Possible role of Streptococcus pyogenes in mucocutaneous lymph node syndrome. VIII. Immunological tolerance to S. pyogenes-associated antigens seems essential to induction of MCLS.

In our previous studies, we attempted to show that new-born mice infected with an attenuated strain of Streptococcus pyogenes, and exposed to streptococcal antigens approximately one month later, failed to develop a humoral response to those antigens but were able to respond normally to other unrelated antigens. Since such immunological characteristics are identical to those of patients with the mucocutaneous lymph node syndrome (MCLS), the present studies were performed with the aim of assessing the antibody-forming activities of peripheral blood lymphocytes collected from MCLS patients. These lymphocytes were cultured in the presence of pokeweed mitogen, streptolysin-O and streptococcal C-polysaccharide, leading to their refractoriness to S. pyogenes-associated antigens coupled with normal responsiveness to unrelated antigens. The implication of such immunological responsiveness elicited from neonatal exposure to streptococcal antigens is discussed, particularly with reference to the induction of MCLS.

Antibody Formation↗

PubMed1989

Possible role of Streptococcus pyogenes in mucocutaneous lymph node syndrome. IX. Quantitation by ELISA of streptococcal pyrogenic exotoxin in the serum of MCLS patients.

In the present paper we describe the use of an enzyme-linked immunosorbent assay reinforced with an introduction of monoclonal antibody, for the detection and quantitation of streptococcal pyrogenic exotoxin (SPE) in the serum of patients with mucocutaneous lymph node syndrome (MCLS). The amount of SPE was usually at a high level, and its 100% incidence in patients' sera was proved whenever the assay was made on the day of admission, thereby showing a marked contrast to carefully matched control sera which failed to mediate any positive result. As for the change in detected amount of the toxin, a clear dichotomy was observed between the serum of gammaglobulin-treated patients and that of infants given aspirin; in the former the positive result turned to negative rapidly following the initiation of treatment coupled with a defervescence, while in the latter the reduction of SPE levels was scarcely monitored for as long as 17 days after the onset of illness. Quantitation of SPE might be an auxiliary test for the diagnosis of MCLS, because a considerable amount of SPE was assessed in a patient who developed characteristic huge coronary artery aneurysms following an illness which did not fulfill the diagnostic criteria. These findings support our speculation in relation to the certain role of S. pyogenes as an etiological agent for MCLS. The possible mechanisms of gammaglobulin treatment in reducing the prevalence of cardiovascular lesions and the duration of systemic inflammation are discussed.

Animals↗

PubMed1988