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Biomedical subjects

R Horie

Publications and source records attributed to R Horie.

At least 91 records · Page 5Linked to original sources
PubMed1981

Genetic markers in spontaneously hypertensive rats.

Establishment of various models for hypertensive diseases such as spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP) clarified the importance of genetic factors in the pathogenesis of these diseases and further accelerated studies on their genetic mechanisms. Although various biochemical abnormalities have been detected and can be used as biochemical markers in these models, they have not been always closely related to blood pressure in F2 generation obtained by cross breeding between SHR and normotensive Wistar-Kyoto rats. Recent studies indicate that biomembrane abnormalities detected in erythrocytes and other membranes of SHR and SHRSP may not only be biochemical markers but also related to the pathogenesis of hypertensive diseases.

Animals↗
PubMed1980

The hypotensive effect of centrally administered tyrosine.

Intraventricular injection of 15 microgram L-tyrosine results in a significant reduction in blood pressure in the spontaneously hypertensive rat. An increase in the turnover of norepinephrine as indexed by MOPEG-SO4 is observed concurrently. The data are consistent with the previously suggested depressor role of certain central noradrenergic neurons.

Animals↗
PubMed1980

Epidemiological analysis on the mechanism of cigarette smoking as a risk factor in cardiovascular diseases.

To clarify the mechanism involved in the contribution of cigarette smoking to increased mortality in patients of cardiovascular diseases (CVD), blood pressure (BP), serum cholesterol (Chl), triglycerides (TG), obesity index (OI), hematocrit (Ht), hemoglobin (Hb) etc, were examined in male smokers and non-smokers among 2500 inhabitants of a farming village in Japan. Smokers were classified by age and by the number (n) of cigarettes smoked per day into mild smokers (1 smaller than or equal to n < 20), moderate smokers (20 smaller than or equal to n < 30) and heavy smokers (n larger than or equal to 30). Ht was increased with the number of cigarettes smoked and was significantly higher in heavy smokers than in non-smokers, in most all the age groups. BP, Chl, TG, OI, Hb etc, showed no significant quantitative relation to the number of cigarettes smoked. This increase in Ht in smokers may represent a risk factor in increasing the morality rate in CVD.

Adult↗
PubMed1980

Abnormal membrane characteristics of erythrocytes in rat models and men with predisposition to stroke.

Erythrocyte membrane characteristics were examined in normotensive Wistar-Kyoto rats (WK), stroke-resistant spontaneously hypertensive rats (SHRSR) and stroke-prone SHR (SHRSP). The membrane of SHRSP was more labile against osmotic shock than that of SHRSR or WK at the age of 2 months. This membrane fragility was not dependent on their blood pressure. The membrane permeability of lipophilic ion, tetraphenylphosphonium, was increased in 1-month old SHRSP. These membrane characteristics in SHRSP were partially dependent on cholesterol amount which was significantly decreased in SHRSP. The method determining the membrane fragility was applied to human erythrocytes. Two groups of people were selected from about 2,000 inhabitants under our community health control program. The erythrocytes from the group with stroke in their family history were more labile than erythrocytes from the corresponding group without stroke in their family history. This result suggests that the examination of these membrane characteristics may give us a new method to detect a genetic risk to hypertension or stroke-proneness also in human.

Adult↗
PubMed1980

Neural factors and genetic disposition in cerebrovascular atherogenesis in rats.

Using newly devised barium-contrasted Sudan staining methods (BCSS method) for the macroscopic overall detection of cerebrovascular ring-like fat deposition, we investigated, qualitatively and quantitatively, the role of the sympathetic nervous system in the development of atherogenesis in the cerebral arteries of spontaneously hypertensive rats (SHR), renal infarction hypertensive rats (RHR) and normotensive Wistar-Kyoto rats (WKR). Upper cervical sympathectomy clearly reduced the susceptibility to vascular fat deposition in the central nervous system of SHR and WKR. In contrast, denervated and intact RHR showed no significant difference in the susceptibility to vascular fat deposition. Susceptibility and degree of the denervation effect were dependent on differences among the strains of SHR. These results suggest the important role of neural factors and genetic disposition, in addition to hypertension, in the initiation of cerebrovascular atherogenesis in rats.

Animals↗
PubMed1979

Cardiac hypertrophy in early hypertension.

Studies of cardiac hypertrophy in spontaneously hypertensive rats have indicated that left ventricular hypertrophy occurred even in the prehypertensive stage. These findings suggested that other factors besides blood pressure levels, and including possibly a genetic predisposition to myocardial hypertrophy, could play a role in structural cardiovascular alterations in spontaneously hypertensive rats. More recent studies have confirmed these anatomic results; left ventricular hypertrophy was vectorcardiographically detected even in the prehypertensive stage in voth young stroke-prone rats and stroke-resistant spontaneously hypertensive rats. Further, a close relation was found between degree of left ventricular hypertrophy and vascular hypertrophy or hyperplasia; this suggests that early detection of left ventricular hypertrophy may be a useful indicator of the incipient stage of structural vascular changes in genetic hypertension.

Adrenergic beta-Agonists↗
PubMed1979

Biochemical alterations of connective tissue metabolism in the arterial walls of stroke-prone spontaneously hypertensive rats.

1. The chemical characteristics of the vascular connective tissue components were determined in stroke-prone (SP), stroke-resistant (SR) spontaneously hypertensive (SH) rats and normotensive Wistar-Kyoto (WK) rats. 2. The ratio of hydroxylysine to hydroxylsine plus lysine in the vascular collagen was increased in 6-month-old SP-SH rats and SR-SH rats as compared with WK rats. 3. An age-related increase in uronic acid and hexose content of the aorta was noted in SP-SH, SR-SH and WK rats. However, the increase was more prominent in SH rats, especially SP-SH rats at the stages examined (11 weeks and over 8 months of age). 4. The ratio of galactosyl-hydroxylysine to glucosyl-galactosyl-hydroxylysine in the aortic collagen was decreased in 6-month-old SH rats, especially SP-SH rats as compared with WK rats. 5. A relative increase in beta and gamma components in aortic collagen was noted in 6-month-old SP-SH rats when compared with SR-SH rats. 6. The increased content of uronic acid and hexose and the structural changes of vascular collagen as demonstrated in SP-SH rats might be related to the fragility of the arterial wall and/or to the pathogenesis of stroke-proneness.

Aging↗