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Biomedical subjects

K Azuma

Publications and source records attributed to K Azuma.

At least 55 records · Page 3Linked to original sources
PubMed1988

Retinoid changes in the in vitro regeneration of frog visual pigments.

To investigate the regeneration of visual pigment, the changes in composition and quantity of retinoids were measured by high-performance liquid chromatography (HPLC). Eye cups or eye cup sections of dark-adapted frogs were exposed to light (greater than 500 nm) and incubated in the dark for several hours (pH 7.4, 27 +/- 1 degree C). Retinoids extracted by the oxime method before and after illumination were analysed by HPLC. In the dark, every eye cup or eye cup section contained 11-cis and all-trans isomers of retinyl palmitate (the proportion of 11-cis was nearly 40%). The amount of retinyl palmitate was 1-1.5 mol equiv of visual pigment. After 80% of the visual pigment had been bleached by illumination, eye cups or eye cup sections were incubated in the dark for 10 h. During the incubation, 70% of the bleached pigment was regenerated, and the proportion of 11-cis retinyl ester decreased from 40% to 13%. These results indicate that stored 11-cis retinyl ester is used for the regeneration. The regeneration rate of A2-pigment (half time = 75 min) was faster than that of A1-pigment (half time = 90 min), consistent with the result of Tsin & Flores' (1986) in vivo experiment with goldfish.

Animals↗
PubMed1987

[Adrenal circulation of rabbits in hemorrhagic and endotoxin shock].

Tissue circulation of the adrenal gland which is known as antishock organ was investigated by the hydrogen clearance method in hemorrhagic and endotoxin shock using rabbits. Mean blood pressure was maintained at 35 mmHg for two hours in the hemorrhagic group, while 2mg/kg of endotoxin was injected intravenously in the endotoxin group. The data obtained were as follows: Adrenal tissue circulation and renal circulation were reduced to 40% and 14.9%, respectively in the hemorrhagic group and reduced to 69% and 48%, respectively in the endotoxin group. Plasma corticosterone concentration was significantly elevated in both groups. Plasma beta-glucuronidase was significantly elevated in both groups and most animals died within 72 hours. From these data we concluded that adrenal circulation was distributed preferentially at the sacrifice of renal circulation in the shocked state.

Adrenal Glands↗
PubMed1986

[Intrinsic endotoxemia after massive hepatectomy--effect of intra-intestinal antibiotics].

It is known that intrinsic endotoxemia is caused by two main mechanisms, reticuloendothelial system dysfunction and intestinal circulatory failure. We investigated the escape of endotoxin from the intestine under occlusion of the superior mesenteric artery 3 days after 70% liver resection in rabbits. Twelve rabbits were given intra-intestinal antibiotics (Antibiotics group) and other twelve rabbits were given saline only (Control group). The results were as follows. Indocyanine green clearance and lipid clearance were deteriorated in both groups after hepatectomy but the antibiotics group showed a better clearance rate than the control group. Serum endotoxin level was elevated slightly after hepatectomy and then grossly elevated after superior mesenteric artery occlusion, but the antibiotics group showed a lower endotoxin level than that of the control group. Seventy-two hours survival rate was apparently better in the antibiotics group. From those data we conclude that the administration of intraintestinal antibiotics contributed to the maintenance of reticuloendothelial function of remnant hepatic lobe and suppressed the serum endotoxin level after superior mesenteric artery occlusion.

Animals↗
PubMed1985

[Correlation between serum prolactin secretion patterns and the ability of fertilization and cleavage of human oocyte (effects of transient hyperprolactinemia on fertilization and cleavage of human oocyte)].

To assess the effect of serum prolactin (PRL) on the fertilization and cleavage of oocytes, its secretion patterns in normoprolactinemic women (28 cases, 35 cycles) who had undergone IVF-ET because of bilateral tubal occlusion and/or severe oligospermia, and the relationship between its levels and the fertilization and cleavage rate were studied. Three serum PRL secretion patterns were observed. In the TIP-O (Transient Increase in serum PRL in the Ovulatory phase) group (7 cycles), the serum PRL was significantly increased in the ovulatory phase compared with the follicular phase. In the TIP-OL (TIP at the Ovulatory and mid-Luteal phase) group (11 cycle), it was significantly increased in both the ovulatory and the mid-Luteal phases, but in the NON-TIP group (17 cycles) there was no significant increase in any phase. The fertilization rate of the TIP-OL group (60.0%) was lower than that of the NON-TIP Group (89.5%) and the TIP-O group (87.5%). The cleavage rate of the TIP-O group (50.0%) was rather lower, and that of TIP-OL group (30.0%) was significantly (p less than 0.05) lower than that of the NON-TIP group (78.9%). These results suggest that transient increase in serum PRL may suppress the ability of fertilization and cleavage of human oocytes.

Adult↗
PubMed1985

Alkali-catalyzed isomerization of some nitrogen-bridged furanosyl uracils to the corresponding pyranosyl cyclonucleosides.

With a view to examine the possibility of introducing an "up" amino residue into the sugar moiety of uracil nucleosides through 2,3'-N-cyclonucleosides, 2,3'-imino and 2,3'-substituted imino-1-(5'-O-benzoyl-beta-D-lyxofuranosyl)uracils, 2a4, 2b5 and 2c-f, were synthesized and debenzoylated correspondingly to 3a4, 3b5 and 3c-f. Hydrolysis of 3a,c,d,e with one to one mixture of 6N-NaOH and EtOH allowed the isolation of the corresponding 2,3'-N-bridged lyxopyranosyl nucleosides 4 in optically active, crystalline form. This is the first example of furanosyl to pyranosyl conversion in the field of pyrimidine cyclonucleosides.

Chemical Phenomena↗
PubMed1984

Effects of anti-shock agents on the re-opened superior mesenteric artery flow.

We investigated intestinal blood circulation after re-opening of a fixed-time occlusion of the superior mesenteric artery (SMA) in rabbits. The SMA root was occluded for 60 minutes, after which blood pressure and SMA flow were monitored for one hundred minutes under the administration with fluid infusion of three anti-shock agents; dopamine, phenoxybenzamine and dexamethasone. The intestinal wall tissue circulation in parallel with SMA flow was also studied. Blood pressure and SMA flow decreased after release of the SMA occlusion (SMAO), as compared those during pre-occlusive time in the control group. Fluid infusion alone did not improve blood pressure and SMA flow. Pre-administration of dexamethasone with fluid infusion improved blood pressure, SMA flow and the survival rate. Phenoxybenzamine with fluid infusion improved SMA flow, despite the low blood pressure. Circulatory damage to the intestinal wall was more extensive than that to SMA flow. These findings suggest that the severity and mortality of SMAO shock was not caused by plasma loss but rather by toxic metabolites and endotoxin from the ischemic intestine.

Animals↗