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Biomedical subjects

K Sekimoto

Publications and source records attributed to K Sekimoto.

34 records · Page 2Linked to original sources
PubMed1990

Acute decrease in vitellogenin synthesis by deprivation of food and water in laying hens.

Vitellogenin synthesis during a decrease in egg production caused by depriving food and water was investigated in Single Comb White Leghorn hens. They were transferred from long days of 14L: 10D to short days of 10L: 14D 5 days before food and water deprivation. Then food was deprived for 5 days and water for 2 days. The body weight was markedly decreased by the treatment and reached its minimum after 5 days. The egg production rate which was 85% before the treatment was nil after 4 days. On day 3 the circulating vitellogenin concentrations, measured by a newly established RIA system, was markedly decreased by deprivation of food and water to 22% of the pretreatment level. The concentrations remained less than 10% during cessation of egg laying. Serum luteinizing hormone (LH) and progesterone concentrations decreased gradually, but estradiol 17 beta (E2) decreased abruptly. This acute decrease closely coincided with the decrease in egg production and the weight of the oviduct and ovary. These concentrations were gradually increased after day 16 and returned to the normal level after 46 days. Circulating thyroxine (T4) and triiodothyronine (T3) concentrations gradually increased from the beginning of the change in the day length and peaked on day 7 or 9, whereas reverse (r)T3 rapidly increased. The concentrations again decreased at the beginning of molting which occurred later due to the deprivation of food and water. Thus, these results demonstrated for the first time that the decrease in egg production induced by deprivation of food and water closely related to the decrease in vitellogenin synthesis as well as gonadal and pituitary functions. Further, recovery of egg production was coupled with the increase in the ovary and oviduct weight, and circulating LH, E2, progesterone, and vitellogenin.

Animals↗
PubMed1987

Thyroxine-induced molting and gonadal function of laying hens.

Twenty laying hens, 238 days of age, were divided into four groups which received daily intramuscular injections of L-thyroxine (T4) (0, 20, 100, or 500 micrograms/kg body weight per day) for 4 weeks. There was no change in body weight or egg production rate of the control (0 microgram T4) or of 20 and 100-micrograms T4 groups over time. Body weight and egg production of the 500 micrograms T4 group decreased markedly and molting started 10 days after T4 injection. Circulating iodothyronine (T4), triiodothyronine (T3), and reverse triiodothyronine (rT3) of the 500-micrograms T4 group increased markedly (30 to 150 times those of the control group) whereas serum luteinizing hormone and progesterone declined after one week and estradiol after two weeks. We concluded that a large dose of T4 (500 micrograms T4/kg, body weight per day) induced an increase in circulating iodothyronine levels, decreased secretion of gonadotropin and sex steroid hormones, and induced molting.

Animals↗
PubMed1987

Nutritional implications of high-iodine egg diet in rats: effects on lipid metabolism and thyroid function.

The effects of a diet including high-iodine eggs, containing much higher amounts of iodine than ordinary eggs, were investigated on lipid metabolism and thyroid function in rats. To a non-purified diet was added at the 1% (w/w) level ordinary egg power (OE diet: 35 micrograms iodine/100 g diet) or high-iodine egg powder (IE diet: 392 micrograms iodine/100 g diet). At 7 months and 19 months, feeding of the IE diet resulted in a lowered serum triacylglycerol level, elevated tissue lipoprotein lipase activity and a lowered lipid peroxide level in the brain. Although the serum total iodine level was 5 times higher in animals given the IE diet than in those given the OE diet, serum levels of thyroid-related hormones (TSH, T3 and T4) were not affected by feeding of the IE diet. In animals exposed to cold and given antithyroid drug treatment, the IE diet seemed to improve age-related defects in thermogenic and thyroid hormone responses to cold, and also to confer resistance to the antithyroid drug. These results suggest that iodine ingestion through high-iodine eggs modulates both lipid metabolism and thyroid function in rats.

Animal Nutritional Physiological Phenomena↗
PubMed1986

Iodine content of various meals currently consumed by urban Japanese.

Various meals being currently consumed by urban Japanese were determined for iodine. The meal samples were collected in 1982 and 1984. The habitual daily home meals of 4 middle-aged Japanese living in urban areas contained 45-1,921 micrograms (mean; 362, 361, 429 and 1,023 micrograms, respectively) of iodine per day. The regular meals served in two university hospitals contained 95-287 micrograms (mean; 195 micrograms) and 89-4,746 micrograms (mean; 1,290 micrograms) of iodine per day, respectively, and the diets for diabetes mellitus contained 59-144 micrograms (mean; 96 micrograms) of iodine per day. In the daily meals containing iodine exceeding ca. 300 micrograms, some kinds of seaweeds and, in some cases, several foods containing a red food color with low iodine bioavailability, erythrosine, provided a large portion of iodine. The iodine contents of refectory meals in a university were 47-203 micrograms (mean; 113 micrograms) per meal and those of lunches in two elementary schools were 25-31 micrograms (mean; 27 micrograms) and 18-43 micrograms (mean; 36 micrograms) per lunch, respectively. These results suggest that the current daily iodine intake of urban Japanese is not great and that erythrosine elevates the iodine content of meals.

Child↗
PubMed1986

Induction of tumor necrosis factor by administration of OK-432 in cancer patients.

We examined whether OK-432, a streptococcal preparation, could induce tumor necrosis factor in cancer patients. OK-432 was administered at a dose of 100 KE intratumorally to 4 advanced gastric cancer patients and 10KE intracavitary to 8 patients with malignant pleuroperitoneal effusion. The cytostatic activity of the sera and malignant effusions was assayed by the growth inhibition of L929 cells. OK-432 induced significant cytostatic activity in the sera and malignant effusions. The activity was partially neutralized by the monoclonal antibody against human recombinant tumor necrosis factor. These data suggest that OK-432 induces tumor necrosis factor in the sera and malignant effusions of cancer patients.

Biological Products↗
PubMed1985

Influences of feeding of high-iodine eggs on hypo- and hyperthyroid rats.

The effects of the feeding of high-iodine eggs to rats with an abnormal thyroid status were investigated. Rats were fed for one week on a commercial diet supplemented with propylthiouracil (PTU) (10 mg/100 g diet) or thyroxine-Na (240 micrograms/100 g diet) respectively, to induce hypo- or hyperthyroidism, and then further fed for 4 weeks on the respective drug-supplemented diets, containing 1% (w/w) of either ordinary or high-iodine egg powder. Control (euthyroid) rats were maintained on the commercial diet. The induction of a hypothyroid state resulted in thyroid hyperplasia, with decreased thyroid iodine content, altered serum thyroid relating hormone levels (increased TSH and decreased T3 and T4), elevated serum total cholesterol and reduced serum triacylglycerol (TG) levels, and also increased muscle and adipose tissue lipoprotein lipase (LPL) activities. In contrast, in the hyperthyroid animals, thyroid atrophy, as well as decreased serum TSH and increased T3 and T4 levels, was associated with reduced serum total cholesterol level and muscle LPL activity. There were no essential differences between animals given high-iodine and ordinary eggs in either hypo- or hyperthyroid state, although the effects of PTU treatment on the thyroid and serum TG level appeared to be slightly lesser in rats given high-iodine eggs than in those given ordinary eggs. It is concluded that high-iodine eggs did not have any side-effect on either hypo- or hyperthyroid rat in this study.

Adipose Tissue↗
PubMed1980

Experimental model for combination chemotherapy with metronidazole using human uterine cervical carcinomas transplanted into nude mice.

Human uterine cervical carcinomas (Yumoto strain) and HeLa cell tumors were transplanted into nude mice, and their transplantable strains were established. The fundamental histological features of these tumors were analyzed according to their histological construction and cytological maturation. The effect of administered drugs was examined morphologically. The Yumoto strain is a well-differentiated epidermoid-type carcinoma consisting of regularly arranged basal-type, parabasal-type, and keratinizing-type cells. The HeLa cell tumor is made up of solid medullary carcinoma cell nests in which trabecular arrangements begin to appear around the medullary areas after the third passage. This feature is maintained up to the 17th generation. The basal layer-type cancer cells of the Yumoto strain as well as trabecularly arranged cancer cells in the HeLa cell tumor were selectively influenced by administration of bleomycin and/or mitomycin and showed considerable degeneration or complete disappearance. On the contrary, metronidazole (a drug for vaginal trichomoniasis; Flagyl) displayed a cytotoxic effect on the parabasal-type and/or more mature cancer cells of the Yumoto strain as well as on the solid medullary area of the HeLa cell tumor. This result may indicate a selective affinity of drugs for malignant cells according to their histological construction, and it is conceivable that these types of carcinoma can be affected by combination administration of metronidazole and oncostatic chemicals such as bleomycin and mitomycin. This speculation was realized in this experimental animal research.

Animals↗
PubMed1976

Kawasaki disease. Relationship with infantile periarteritis nodosa.

Until 1972, Kawasaki disease, or acute febrile infantile mucocutaneous lymph node syndrome (MCLS), was considered in Japan to be a nonfatal disease with a favorable prognosis. Based on the findings from two autopsy cases of MCLS, we believe that sudden and unexpected death during convalescence may be due to arterial lesions, especially those involving the coronary artery, that resemble those of periarteritis nodosa. Of 29 autopsy cases of MCLS, gathered from all over Japan, all exhibited arteritis lesions (eg, aneurysm due to coronary arteritis). Such vascular pathological findings may in fact represent the same entity as infantile periarteritis nodosa. Whether infantile periarteritis nodosa can be identified with the adult type is still debatable. The particular manifestations of infantile periarteritis nodosa might be related to severe vasculitis. Autopsy cases of infantile periarteritis nodosa without MCLS manifestations are being collected and studied.

Age Factors↗