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Biomedical subjects

Y Tagashira

Publications and source records attributed to Y Tagashira.

At least 73 records · Page 4Linked to original sources
PubMed1979

[Comparison of different types automatic water-supply system for mouse rearing (author's transl)].

Rearing and breeding scores were compared between groups of mice (JCL : ICR and ddN strains) raised with two different types of automatic water-supply systems; the Japanese type and the American type, using manual water-supply system as control. The mice raised with the manual water-supply system were superior in body weight gain as compared to those with two automatic water-supply systems. As to the survival rate, however, the m; anual water-supply system and the Japanese type gave better results than the American type. As to weanling rate in the breeding test, the manual water-supply system gave somewhat better result than either of the two automatic types. Accidental water leaks, which are serious problems of automatic systems, occurred frequently only when the American type was used. Only one defect of the Japanese type revealed was that it was unfavorable for mice with smaller size (e.g., young ddN mice), resulting in lower body weight gain as well as lower breeding scores.

Animals↗
PubMed1978

Positioning of the A . T-rich regions in rat mitochondrial DNA by electron microscopy and analysis of the hysteresis of denaturation.

Intramolecular heterogeneity in the base composition of rat mitochondrial DNA (mtDNA) was shown by a combination of an improved denaturation mapping technique using electron microscopy and analysis of high-resolution optical melting-renaturation profiles. Circular mtDNA starts to melt in one specific region and then forms loops in four other regions in random order. These five early melting regions are all located in one half of the molecule. The arrangement of the early melting regions in rat mtDNA bears a remarkable resemblance not only to those of mtDNAs from several species of Drosophila but also to those of several species of Drosophila but also to those of several plasmid DNAs and phage DNA.

Animals↗
PubMed1978

The differences between the primary structures of mitochondrial DNAs from rat liver and ascites hepatoma (AH-130).

Rat mitochondrial DNAs (mtDNAs) of ascites hepatoma (AH-130) and normal liver cells (Donryu strain) were digested by various restriction endonucleases and the cleavage patterns compared by agarose gel electrophoresis. Different cleavage patterns were observed between AH-130 and liver mtDNAs when they were digested by HindII and EcoRI. The mtDNA of AH-130 lost one clevage site of HindII and one clevage site of EcoRI. The cleavage patterns of mtDNAs from other organs and strains tested were the same as that of liver mtDNA. From these observations we concluded that the molecular clone of AH-130 mtDNA was different from that of other mtDNAs.

Amino Acid Sequence↗
PubMed1978

Biphasic change of proton magnetic relaxation times during azo-dye hepatocarcinogenesis.

For the first time, change in the proton longitudinal relaxation times (T1) of rat tissues has been examined throughout the whole process of azo-dye hepatocarcinogenesis. Two maxima of the T1 values were observed for liver, on Day 60 and after Day 120, and these changes correlated well with the changes in water content. The first peak was ascribed to the immature hepatocytes of hyperplastic nodules, and the second peak to the developed hepatoma cells. The significance of the change in T1 values as a preneoplastic change is discussed.

Animals↗
PubMed1978

Cerebral tissue response to reserpine: a morphological study.

The acute influence of reserpine injection on cerebral tissue was studied in baboon and rat models. Five h after the infusion of reserpine, bilateral cortical areas were found to contain perivascular changes only, whereas basal ganglia regions contained advanced oedematous responses. Mitochondrial swelling was commonly found in the latter regions, as were loci containing microvascular crenation with accompanying pericytic changes.

Animals↗
PubMed1978

In vitro binding of 2-acetaminofluorene to RNA and protein with rat liver microsomes.

Covalent binding of 2-acetaminofluorene[9-14C] with exogenous Torula yeast RNA and endogenous protein was investigated in liver microsome system in vitro. The binding to protein was 100 times higher than that to RNA. Requirement of NADPH, effectiveness of methylcholanthrene treatment, and inhibition by 7,8-benzoflavone suggest possible involvement of mixed-function oxidases in this binding. The binding was not due to contaminated cytosol in the microsome fraction. Addition of cytosol, sulfate ion, and ATP diminished the binding. Parallel experiments using N-hydroxy-2-acetaminofluorene[9-14C] denied major contribution of this metabolite to the binding of 2-acetaminofluorene in the microsome system. Ring-hydroxylated product was suggested as a possible metabolite for the binding.

2-Acetylaminofluorene↗
PubMed1977

Effects of cyclic AMP and dibutyryl cyclic AMP on cerebral hemodynamics and metabolism in the baboon.

Adenosine 3',5'-cycle monophosphate (cyclic AMP) (0.5 mg/kg) was infused into the carotid artery of baboons anesthesized with sodium pentobarbital, causing a biphasic increase in cerebral blood flow (CBF) and reduction in cerebrovascular resistance (CVR) associated in each phase with stimulation of cerebral metabolism evidenced by increased cerebral oxygen consumption (COMRO2) and cerebral glucose consumption (CMRG1). Intracarotid dibutyryl cyclic AMP (0.5 mg/kg) caused a monophasic increase in CBF and reduction of CVR but failed to alter cerebral metabolism. This may be due to its rapid removal from the circulation with ineffective passage across the blood-brain barrier since intracisternal infusion of dibutyryl cyclic AMP caused sustained increase in CBF, CMRO2 and CMRG1 and reduction in CVR. Intracarotid AMP (0.4 mg/kg) and adenosine (0.3 mg/kg) caused an immediate and more marked increase in CBF and decrease in CVR unassociated with cerebral metabolic change making it unlikely that the observed effects of cyclic AMP can be attributed to its breakdown products. Cyclic AMP or its dibutyryl derivative may alter cerebral metabolism secondary to neuronal activation but increase in glucose/oxygen utilization ratio after intracarotid cyclic AMP and intracisternal dibutytyl cyclic AMP also suggests an influence on enzymatic regulation of glucose metabolism.

Adenosine↗
PubMed1976

Acute ultrastructural changes in the middle cerebral artery due to the injury and ischemia of surgical clamping.

Ultrastructural changes in the zone of clamping of the middle cerebral artery of the squirrel monkey are described after application of a surgical clip. The experimental model utilized has been widely applied to the study of cerebral ischemia and possibly has relevance to clamps applied to the cerebral vessels during neurosurgical treatment of patients with cerebrovascular disorders. The earliest changes within the arterial wall were found in the smooth muscle (media) and accompanying fasciculi of nerves. Changes within the nerve bundles were sufficiently advances following 4 hours of vascular clipping to suggest temporary or permanent impairment of neurogenic innervation of the cerebral vessels distal to the trunk of the vessel clipped.

Animals↗
PubMed1976

Effect of acetylcholine on cerebral circulation.

Effects of intravertebral, intracarotid, and intravenous infusion of acetylcholine on cerebral blood flow (CBF) and metabolism was studied in 17 baboons anesthetized with pentobarbital. We measured CBF by the bilateral jugular venous outflow technique using two electromagnetic flowmeters. Effect of acetylcholine infusion on cerebral vascular response to hypercapnia was also assessed. Intravertebral infusion of acetylcholine (0.01 mg/kg/min) increased CBF by 27% and cerebral metabolic rate for oxygen by 19% and decreased cerebral vascular resistance by 25%. On intracarotid injection of acetylcholine, only an 8% increase in CBF was observed, and intravenous infusion produced no change in the parameters observed. Acetylcholine administered by any of the three routes did not enhance the CBF response to hypercapnia. Increase in CBF on intravertebral administration of acetylcholine is associated with an arousal effect and an increase in cerebral metabolism.

Acetylcholine↗
PubMed1975

The effects of glycerol on cerebral ultrastructure following experimentally induced cerebral ischemia.

Ultrastructural changes in cerebral tissue subjected to temporary occlusion on the right middle cerebral artery for intervals of 30 min, 1, 2, 3, and 4 hr were studied after daily injections of 10% glycerol in saline. These changes were compared with previously reported data from untreated animals. The extent of tissue involvement was appreciably less in the glycerol-treated group as evidenced by the reduction of intracellular edema and fewer changes in the membranes of ultrastructural elements (mitochondria, endoplasmic reticulum, Golgi complex, and plasmalemma) known to be essential for cellular metabolism and function in the central nervous system.

Animals↗
PubMed1975

The ultrastructure of the middle cerebral artery and its associated nerve fibers in the squirrel monkey and baboon.

This study describes the ultrastructural characteristics of the middle cerebral artery and its related neural elements in the squirrel monkey and baboon. The cytoarchitecture of the M-1 segment as well as that of the smaller extracerebral and intracerebral vessels is comparable in both animals. Smooth muscle elements are occasionally found within the intimal lining. The nerve bundles associated with vessels contain fewer myelinated fibers as the vessel diameter decreases. The cytological relationship between the neural structures and the smooth muscle cells are discussed.

Animals↗
PubMed1975

Morphological responses of cerebral tissues to temporary ischemia.

The ultrastructural responses of cerebral tissue following temporary periods (1/2, 1,2,3, or 4 hour) of right, middle cerebral artery, (MCA) occlusion were studied acutely after a 3 day or 7 day interval following the removal of the MCA clip. Cortical and basal ganglia tissues for each ischemic duration were compared at 3 post-occlusive periods (acute, 3 days, 7 days). With the short periods of ischemic insult (1/2, 1, 2, 3, and 4 hour), the temporal and insular cortex contained no greater changes in the 7 day group than in the 3 day group. The basal ganglia were more susceptible to MCA occlusion as indicated by more marked cytological changes and/or necrosis in all intervals of ischemia.

Acute Disease↗
PubMed1975

Regional cerebral blood flow changes after bilateral external carotid artery ligation in acute experimental infarction.

Regional cerebral blood flow (rCBF) was measured in baboons by intracarotid injection of 133Xe and a gamma camera after acute cerebral infarction was induced by occlusion of the middle cerebral artery (MCA). A steady state of rCBF was measured four hour after MCA occlusion and was followed by bilateral ligation of the external cartoid arteries (ECA). Subsequent rCBF measurements were obtained at 30, 60, and 120 minutes. After bilateral ECA ligation, flow in ischaemic and non-ischaemic areas was greatly enhanced and flow in the hyperaemic areas significantly reduced, presumably since they had provided collateral circulation to the ischaemic zone with a favourable redistribution.

Acute Disease↗