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Biomedical subjects

K Akiba

Publications and source records attributed to K Akiba.

35 records · Page 2Linked to original sources

Artificial placenta: long-term extrauterine incubation of isolated goat fetuses.

Previously, this group reported on a system of extrauterine incubation of a goat fetus, in which the fetus is surrounded by artificial amniotic fluid and connected to the circuit with an ECMO (extracorporeal membrane oxygenator) by the umbilical arteries and veins. The following is a summary of recent progress using an improved method of catheterization and a new system that included a dialyzer within the circuit. Nine goat fetuses were used in this experiment. Six goats were successfully incubated; the duration of their incubation was 146.5 +/- 61.3 h (mean +/- SD). The longest one was 236 h. Slowly progressive circulatory depression was thought to be the main cause of fetal death. Marked tendencies to bleeding and water retention were not observed in any cases. Stable serum electrolyte levels were maintained.

Animals↗

Isolation of Akabane virus from the biting midge Culicoides oxystoma in Japan.

Akabane virus was isolated from the biting midge, Culicoides oxystoma, collected in a cowshed in Kagoshima on Kyushu Island of Japan. This is the first report on the isolation of Akabane virus from biting midges of the genus Culicoides in Japan. Two calves kept as bait in the cowshed seroconverted to Akabane virus. These results strongly suggest that C. oxystoma may be a vector of Akabane virus.

Animals↗

Development of second generation merozoites of Leucocytozoon caulleryi in vitro.

Sporozoites of Leucocytozoon caulleryi were inoculated into specific-pathogen-free (SPF) chickens intravenously. Fourteen days after inoculation, the infected blood, parasitized with second generation merozoites, was collected from the chickens. The blood was then suspended in SPF chicken serum or RPMI-1640 culture medium supplemented with 20% SPF chicken serum in petri dishes, which were cultured at 37 degrees C or 41 degrees C in a humidified atmosphere of 5% CO2. Second generation merozoites in parasitized, immature erythrocytes developed continuously through several substages and finally became micro- and macro-gametocytes after 6 days of incubation.

Animals↗

Indirect immunofluorescent antibody test in chicken leucocytozoonosis.

The indirect immunofluorescent antibody technique was applied to detection of antigens of different developmental stages of Leucocytozoon caulleryi and antibodies in the sera of chickens infected with L. caulleryi by using second generation merozoite and gametocyte antigens. Zygotes, ookinetes and sporozoites in midges, and second generation merozoites and gametocytes in chickens indicated specific fluorescence. Indirect immunofluorescent antibody titers were higher than agar gel precipitation antibody titers. So the detection of the antibody by the indirect immunofluorescent antibody technique was possible in the sera in which the antibody could not be detected by the agal gel precipitation test. Therefore, the indirect immunofluorescent antibody technique was applicable to chicken leucocytozoonosis as a highly sensitive serological diagnostic method.

Animals↗

[Effect of d-pseudoephedrine on the central nervous system in mice].

Some pharmacological actions of intraperitoneally (i.p.) administered d-pseudoephedrine (d-pseudo) on the central nervous system of mice were compared with those of l-ephedrine (l-eph). Locomotor activity was increased by l-eph (50, 100 and 200 mg/kg,) but not by d-pseudo (50, 100 and 200 mg/kg). Wheel-revolving activity was reduced by a 200 mg/kg dose of both drugs. Rectal temperature was increased by l-eph at 50, 100 and 200 mg/kg. However, it was decreased by 50 and 100 mg/kg doses of d-pseudo, and the change in response to 200 mg/kg of d-pseudo was biphasic, decreasing first and increasing subsequently. Pentobarbital-induced sleeping time was shortened by l-eph (50 and 100 mg/kg), but was not influenced by any of the doses of d-pseudo. In the experiment on locomotor activity, L-3,4-dihydroxyphenylalanine (400 mg/kg, i.p.) potentiated the effects of d-pseudo and l-eph, but reserpine (1 mg/kg, day X 5 days, i.p.) and 6-hydroxydopamine (40 micrograms/mouse, intracerebroventricular injection) potentiated only the effect of l-eph. These results suggest that the effect of d-pseudo on the central nervous system of mouse is not only weaker than that of l-eph, but also the mechanisms of action of these two substances are different.

Animals↗

[Interaction of d-pseudoephedrine with water soluble extracts of Platycodi Radix on acute toxicity (author's transl)].

Effect of various combinations of Platycodi Radix water soluble extracts (Pla), 1-ephedrine (1-eph), d-pseudoephedrine (d-pseudo) and Ipecacuanhae Radix water soluble extracts (Ipe) on acute toxicity were examined in mice. Oral LD50 of Ipe, d-pseudo and 1-eph was 490 (415--578) mg/kg, 1550 (1360--1767) mg/kg and 1400 (1102--1778) mg/kg, respectively, while that of Pla was over 10 g. LD50 of Pla Ipe, d-pseudo and 1-eph given intraperitoneally was 1400 (1228--1596) mg/kg 235 (210--263) mg/kg, 245 (229--262) mg/kg and 300 (259--348) mg/kg, respectively. The ratio of the predicted LD50 value, which was calculated on the assumption that each component drug would be additively toxic when combined, to the observed LD50 value was used for comparison. The combination of d-pseudo with Pla gave a significantly greater LD50 value than the predicted LD50 value, while the combination of 1-eph with Pla showed a LD50 value which was not significantly different from Finney's additive model. A combination of d-pseudo with 1-eph and Ipe, and of 1-eph with Ipe showed a LD50 value which was not significantly different from that of the additive model.

Animals↗

[Effects of d-pseudoephedrine on tracheo-bronchial muscle and the cardiovascular system (author's transl)].

The action of d-psuedoephedrine on bronchial smooth muscle, respiratory resistance and blood pressure was compared with that of 1-ephedrine. The following results were obtained. 1) Administration of dl-isoproterenol on isolated guinea pig tracheal muscle previously constricted with acetylcholine (ACh) or histamine (his) was the most effective and d-pseudoephedrine had the same effect as 1-ephedrine. The relaxing effect of dl-isoproterenol, 1-ephedrine or d-pseudoephedrine on ACh or His induced tracheal constriction was competitively antagonized by the pretreatment of propranolol. 2) The intravenous or sublingual administration of d-pseudoephedrine on the increased respiratory resistance induced by His produced the same effect as 1-ephedrine. 3) The increase in blood pressure with d-pseudoephedrine was weaker than that of 1-ephedrine. 4) When 1-ephedrine of d-pseudoephedrine was repeatedly injected into the same animal, signs of tachyphylaxis were observed. It was found that d-pseudoephedrine, the main alkaloid of Ephedrine Helba, exhibited the relaxing effect on bronchial smooth muscles as did 1-ephedrine. The respiratory resistance increased by His was inhibited by the sublingual administration of d-pseudoephedrine and 1-ephedrine.

Administration, Oral↗