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Biomedical subjects

M Korenaga

Publications and source records attributed to M Korenaga.

68 records · Page 4Linked to original sources
PubMed1984

Effect of androgen on the expression of the sex difference in susceptibility to infection with Strongyloides ratti in C57BL/6 mice.

The possible site of expression of the sex difference in susceptibility to infection with Strongyloides ratti was studied in C57BL/6 mice. The intensity of infection, measured by daily larval output in faeces or by intestinal worm burden, was significantly higher in males than in females. This sex difference was already expressed during the migration of larvae from the site of subcutaneous inoculation to the cranial cavity or lung as early as 24 h after infection. Conversely, there was no significant difference in the larval output in faeces or in the worm burden of male or female recipients after implantation of adult worms using a stomach tube. When the susceptibility to infection with S. ratti of gonadectomized animals was examined, the daily larval output in faeces of orchidectomized males was significantly reduced to the level of intact females, while ovariectomy had no effect, suggesting that androgen is one of the important regulatory factors for the expression of sex difference. In fact, testosterone treatment of orchidectomized males or normal females could increase their susceptibility to or above the level of intact males. These results strongly suggest that sex difference in the susceptibility to infection with S. ratti in C57BL/6 mice is mediated by 'natural defence mechanisms' which are under the regulation of testosterone.

Animals↗
PubMed1983

Strongyloides ratti: the role of enteral antigenic stimuli by adult worms in the generation of protective immunity in rats.

Immunogenicity of adult Strongyloides ratti was studied in rats. Immunization of rats by intraduodenal implantation of adult worms could completely inhibit the egg production and hasten the expulsion of challenged worms which were developed from subcutaneously inoculated L3 or were implanted intraduodenally as adults. Enteral immunization by intraduodenal implantation of adult worms was, however, not able to affect the esophageal larval output of the challenge infection with L3. In contrast to enteral immunization with adult worms, immunization by full sequence of a primary infection or by a combination of drug-abbreviated infection and adult worm implantation could suppress the esophageal larval output of the challenge infection. The relationship between the host defense mechanism and the life cycle of S. ratti is discussed.

Animals↗
PubMed1983

Effects of preintestinal larval antigenic stimuli on the generation of intestinal immunity in Strongyloides ratti infection in rats.

Generation of intestinal immunity by antigenic stimulation with preintestinal, tissue-migrating larvae was investigated in the Strongyloides ratti-rat model. The results of daily fecal egg counts showed that the intestinal immunity against adult worms could be partially generated by priming with preintestinal migrating larvae. A further study demonstrated that this partial reduction of daily fecal egg count was mainly the result of inhibitory effects on the fecundity of the parasitic females, although the expulsion of the parasite from the gut could be advanced by several days. After tertiary immunization with preintestinal larvae, no significant potentiation in the protection was observed when compared with the rats treated by primary immunization alone.

Animals↗
PubMed1982

Rifampicin-induced early phase hyperglycemia in humans.

Early phase hyperglycemia, associated with increased rates of insulin and C-peptide secretion after oral administration of 100 g glucose, was observed among patients with pulmonary tuberculosis who were taking rifampicin. This early phase hyperglycemia appeared shortly after rifampicin was started and it disappeared completely a few days after rifampicin was discontinued. No difference in oral glucose tolerance was noted between healthy normal subjects and patients with pulmonary tuberculosis who were not taking any medications. Antituberculous drugs other than rifampicin did not induce early phase hyperglycemia. Because intravenous glucose tolerance was normal in patients treated with rifampicin, it is suggested that rifampicin produces an early phase hyperglycemia possibly by augmenting intestinal absorption of glucose.

Administration, Oral↗
PubMed1982

Stage-specific cross-resistance between Nippostrongylus brasiliensis and Strongyloides ratti (Nematoda) in rats.

Stage-specificity of cross-resistance between Nippostrongylus brasiliensis and Strongyloides ratti was investigated. Results showed that immunization with tissue-migrating larvae was sufficient to generate cross-resistance and that host defense mechanisms operating in the cross-resistance were directed against tissue-migrating larvae but not against intestinal adult worms. In addition, no significant potentiation of the cross-resistance was observed after multiple immunization. These observations suggest that host defense mechanisms against heterologous challenge infection were qualitatively and/or quantitatively different from those against homologous challenge infection.

Animals↗
PubMed1981

Changes in mechanical properties of the circular muscle of the isthmus of the human fallopian tube in relation to hormonal domination and postovulatory time.

Using the isthmic circular ring from 76 subjects, the authors investigated the in vitro mechanical response of the fallopian tube to noradrenalin and field stimulation. In the proliferative and menopausal phases, preparations with high plasma levels of estradiol showed a high contractile response. In the secretory phase, responses were inhibitory or low at 4 to 6 and 11 to 14 days after the elevation of basal body temperature and were excitatory at 0 to 3 and 7 to 10 days. The exogenous application of estradiol failed to suppress these inhibitory responses. The findings suggest that the inhibitory response at 4 to 6 days after the elevation of BBT may aid in the release of the ovum from the fallopian tube and that after the ovulation, progesterone is mainly related to the response of the circular muscle to noradrenalin.

Acetylcholine↗
PubMedDate not supplied

A report of the first case of Dirofilaria infection in the eyelid region in Japan.

Dirofilaria worms were recovered from a painless hard tumor in the right eyelid of a 19-year-old Japanese male who had lived in Kagoshima and Kumamoto Prefectures, Japan. In the worms, the cuticle had a smooth surface, the inner cuticular layer had internal lateral longitudinal ridges, and the musculature of the body wall was the polymyarian type. On the basis of all morphological characteristics observed, this worm was identified as an immature female Dirofilaria immitis. This is the first human case of nematode infection in the eyelid in Japan. Surgical removal of the mass with worms resulted in complete recovery from swelling of his right eyelid.

Adult↗