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Biomedical subjects

T Shida

Publications and source records attributed to T Shida.

At least 181 records · Page 10Linked to original sources
PubMed1986

Preventive effects of cyclosporin on diabetes in NOD mice.

Non-obese diabetic mice aged 30 to 60 days were treated orally with Cyclosporin at doses of 25, 15 and 2.5 mg/kg every 2 days until 160 days of age. Diabetes developed in 12 out of 18 oil-treated mice (67%), with partial to complete Langerhans' islet destruction associated with lymphocytic infiltration. The non-obese diabetic mice showed a plasma glucose concentration of 6.62 +/- 0.92 mmol/l (mean +/- SD) at 50 days of age. The plasma glucose level of oil-treated non-obese diabetic mice gradually increased after 130 days of age and reached 14.0 to 19.0 mmol/l at 160 days of age, while Cyclosporin-treated non-obese diabetic mice showed neither clear increase of plasma glucose levels nor development of insulitis. The cumulative incidence of diabetes in Cyclosporin-treated mice was significantly lower than that in oil-treated mice (p less than 0.01). Subsequently, Cyclosporin treatment was started after development of glucose intolerance. Twenty-five mg/kg of Cyclosporin was administered every 2 days for 35 days. Cyclosporin appeared to have little therapeutic effect on diabetes in non-obese diabetic mice.

Animals↗
PubMed1986

Effects of tension on local blood flow in experimental intestinal anastomoses.

In intestinal anastomoses, local blood flow is one of the most important factors contributing to the success of the healing process. While submucosal local blood flow is maintained better in the colon than in the small intestine, the incidence of anastomotic leakage is higher in the former than in the latter. To resolve this conflict, we have examined differences in the reactivity of the intestinal segments toward the application of tension. Anastomosis was performed with a stapler on the jejunum, ileum, and colon of experimental dogs. The anastomotic sites were subjected to tensile loads applied in incremental steps to measure and compare local blood flow, measured by the hydrogen clearance method, in the submucosal layers of the anastomoses in these intestinal segments. The results of these comparative evaluations indicate that, at a tensile stress level of more than 4 g/mm2, local blood flow in the colon is significantly smaller than that in the jejunum and ileum. These findings were corroborated by microangiographical observations carried out during stress application. The microangiographical data suggest that the rate of filling of the contrast medium is lower with colonic anastomosis than with jejunal and ileal anastomoses. In addition, the intraluminal pressure of the colon was higher than that of the small intestine during the induced peristalsis. The different sensitivity of the local microcirculation systems of the intestinal segments to tension may thus be considered one of the factors accounting for the higher incidence of clinical suture failure in colonic than in small intestinal anastomoses.

Animals↗
PubMed1986

Allergen induced histamine release and immunoreactive-leukotriene C4 generation from leukocytes in mite sensitive asthmatic patients.

Leukocytes from mite sensitive asthmatic patient were challenged with the allergen and the supernatant was assayed for histamine and immunoreactive-leukotriene C4 (i-LTC4). The release of histamine was quantitated by an automated fluorometric technique and i-LTC4 was determined using a commercial radioimmunoassay kit. The results of analysis of the supernatant by high speed liquid chromatography, together with observations of modulation of the formation by agents, indicated that i-LTC4 consisted of LTC4 with a little amount of LTD4. i-LTC4 was generated as a result of basophil activation but not derived from the other cells such as monocytes and eosinophils. Allergen induced a concentration-dependent release of histamine and i-LTC4 and the maximal release of histamine and i-LTC4 occurred at the same dose of the allergen. At optimal concentration of the allergen, basophils produced 20.4 +/- 17.9 ng of i-LTC4/10(6)-cells (mean +/- S.D., n = 39) and histamine release was 55.6 +/- 20.1% of total histamine. There was a significant correlation in the capacity of leukocytes to release histamine and i-LTC4 (r = 0.47, p less than 0.01). We found a correlation between maximal histamine release or cell sensitivity, allergen concentration for 50% histamine release, and a ratio of specific IgE to mite to total IgE in the serum, but the amount of i-LTC4 failed to correlate significantly with the ratio. The releasability and the cell sensitivity of asthmatic patients' cells to the allergen for histamine release paralleled the severity to symptoms, but this correlation was not significant in i-LTC4 generation.

Adult↗
PubMed1986

Protective effect of zinc against lethality in irradiated mice.

The protective effect of zinc against radiation hazard was observed by comparing LD50(30) values of irradiated mice with and without the administration of zinc before irradiation. Two hundred male mice, 7 weeks old, were irradiated with an intestinal dose at 5.62, 6.31, 7.08, 7.94, 8.91, or 10.00 Gy, with or without oral administration of zinc from 10 days prior to gamma irradiation until the end of the study. The reduction of mortalities in zinc-administered mice in comparison to controls was most prominent at the dose of 7.94 Gy, i.e., the mortality rate in the zinc-administered group was 0.44 and that in the control group was 1.00. At a dose of 8.91 Gy, zinc-administered mice survived significantly longer than controls. The LD50(30) of zinc-administered mice was 7.70 Gy, while that of the control was 6.90 Gy. In zinc-administered mice the acceleration of turnover and elevated excretion of radioactive zinc were observed, while the concentration of stable zinc in organs remained constant. The effect of zinc was not observed in experiments in vitro using human melanoma cells. Therefore it can be assumed that the protective effect of zinc against radiation would correlate with the homeostatic mechanism of zinc which exists in the whole body of mammalians.

Animals↗
PubMed1986

Effect of AA-861, a 5-lipoxygenase inhibitor, on leukotriene synthesis in human polymorphonuclear leukocytes and on cyclooxygenase and 12-lipoxygenase activities in human platelets.

AA-861, a selective inhibitor of 5-lipoxygenase of arachidonic acid, was tested for ability to inhibit leukotriene C4 and leukotriene B4 synthesis in human polymorphonuclear leukocytes after calcium ionophore stimulation. AA-861 dose-dependently inhibited leukotriene B4 and leukotriene C4 generation in human polymorphonuclear leukocytes; the concentration required to inhibit generation by 50% (IC50) was 3 X 10(-7) M for leukotriene B4 and 1 X 10(-8) M for leukotriene C4. BW-755C inhibited the generation of leukotriene C4 with an IC50 of about 10(-5) M, indicating that AA-861 is about 1,000 times more potent than BW-755C. AA-861 did not affect the activity of either cyclooxygenase or 12-lipoxygenase at a concentration up to 10(-5) M in human platelets. AA-861 did not inhibit histamine release from human basophils. These results indicate that AA-861 selectively inhibits 5-lipoxygenase but not cyclooxygenase or 12-lipoxygenase in human specimens.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1986

Isolation and characterization of two allergens from Dermatophagoides farinae.

Two purified allergens, designated as DF1 and DF2, were isolated from the extract of the whole culture of Dermatophagoides farinae by a combination of ammonium sulfate precipitation and ion exchange, hydrophobic, chelate and gel chromatography. DF1 was isolated as a heat-sensitive acidic protein with an apparent molecular weight of 25,000 and an isoelectric point of 4.6-7.2. DF2 was isolated as a heat-stable basic protein with an apparent molecular weight of 15,000 and an isoelectric point of 7.8-8.3. No allergenic cross-reactivity was seen between DF1 and DF2. Both DF1 and DF2 were shown to be the major allergens of D. farinae by the results of radioallergosorbent test and histamine release assay.

Allergens↗
PubMed1986

Immunopharmacological actions of the new antiallergic drug 11-oxo-11H-pyrido[2,1-b]quinazoline-2-carboxylic acid. Effects on type I hypersensitivity reactions in human leukocytes and in human and monkey lungs.

The effects of 11-oxo-11H-pyrido[2,1-b]-quinazoline-2-carboxylic acid (Sm 857), a new antiallergic drug, on histamine release from human leukocytes and from human and monkey lungs were investigated. Sm 857 dose-dependently inhibited histamine release induced by mite antigen, anti-human IgE, calcium ionophore A23187 (A23187) and protein A from peripheral leukocytes of atopic patients, but had no effect on the levels of cyclic AMP and GMP in human leukocytes. In addition, antigen- or anti-human IgE-induced anaphylactic histamine release from human and monkey lung fragments passively sensitized with human reaginic serum sensitive to mite antigen as well as A23187-induced histamine release from non-sensitized monkey lung fragments, were inhibited dose-dependently by Sm 857. However, no inhibition of spontaneous histamine release from human leukocytes or monkey lung fragments by Sm 857 was observed.

Animals↗