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Biomedical subjects

R Horie

Publications and source records attributed to R Horie.

At least 55 records · Page 3Linked to original sources
PubMed1990

Stroke-prone spontaneously hypertensive rats as a model for toxemia of pregnancy and aggravating and preventive effects of maternal modifications during pregnancy on offspring's growth.

Genetical differences in changes in blood pressure (BP) were chronologically investigated during pregnancy in stroke-prone spontaneously hypertensive rats (SHRSP), Wistar-Kyoto rats (WKY) and Sprague-Dawley (SD) rats. Especially, the early stages were carefully studied. Maternal conditions in SHRSP were modified by the treatments with NaCl and taurine, respectively. BP in SHRSP and WKY rose significantly at the early stage of pregnancy compared to prepregnancy levels (SHRSP; 208 +/- 2 mmHg vs 197 +/- 5 mmHg, WKY; 133 +/- 2 mmHg vs 126 +/- 1 mmHg) (p less than 0.05). In contrast, no such changes were observed in SD rats. Differences in 24-hour urinary epinephrine excretion before and during pregnancy ran parallel with such BP changes among these strains. NaCl-loaded SHRSP died during pregnancy with severe pathohistological changes in their kidneys and severe proteinuria. Taurine treatment had a marked prophylactic effect on these maternal pathological changes during pregnancy, resulting in better growth in offsprings. These results suggest that SHRSP could be one of the suitable animal models for the studies on toxemia of pregnancy and also suggest an important role of hypertensive genetical disposition in the development of toxemia of pregnancy.

Animals↗
PubMed1990

Alcohol consumption as a risk factor for high blood pressure from the Cardiovascular Diseases and Alimentary Comparison Study. CARDIAC Cooperative Research Group).

The relationship between alcohol consumption and blood pressure (BP) was studied in 29 centers in 12 countries as part of the International Cooperative Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study. From each population, 100 men and 100 women aged 50-54 were randomly selected for BP measurement by automated system and for a standardized interview to complete the questionnaire relating to alcohol consumption. In cross-center simple linear regression analysis, mean alcohol consumption calculated from a previous week's drinking did not show a linear association to BP. In within-center multiple linear regression analysis, relationships between high alcohol intake (much greater than 300 g/week) and BP were assessed among 26 centers with high alcohol drinkers after being adjusted for other confounding variables. Positive associations of high alcohol intake with systolic BP (SBP) and diastolic BP (DBP) were noted in 17 and 16 centers, respectively. Thus, high alcohol intake was positively and independently associated with BP in individual subjects.

Alcohol Drinking↗
PubMed1990

Comparative studies on the relation between nutritional conditions and blood pressure levels of two rural populations with lower incidences of ischemic heart diseases in Japan and Spain.

Comparative studies on nutritional constituents and blood pressure (BP) levels were performed in two rural areas--in Japan (Ohda) and Spain (Navas)--with low incidences of ischemic heart disease. BP levels of both populations were relatively low, probably resulting from potassium- and magnesium-rich Mediterranean diets in Navas and from fish protein-rich Japanese diets in Ohda assessed by 24-h urine analyses according to the World Health Organization (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study.

Blood Pressure↗
PubMed1990

Relationship between dietary factors and blood pressure in China. The Sino-Japan CARDIAC Cooperative Research Group.

As part of the international cooperative Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study, we carried out surveys for the relationship of dietary factors to blood pressure (BP) in 10 areas in China, (Altai, Beijing, Guangzhou, Guiyang, Hetian, Lhasa, Shanghai, Shijiazhuang, Tulufan, and Urumqi). Systolic BP and diastolic BP were significantly positively associated with salt excretion and body mass index. However, 3-methylhistidine divided by creatinine, and taurine divided by urea nitrogen in 24-h urine were significantly negatively associated with both BPs. These results suggest that meat protein intake may beneficially influence BP, whereas salt may adversely affect BP.

Blood Pressure↗
PubMed1990

International cooperative study on the relationship between dietary factors and blood pressure: a report from the Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study.

To investigate the epidemiological relationship of dietary factors to blood pressure (BP) and major cardiovascular diseases, we carried out the International Cooperative Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study, which so far involves 45 centers in 20 countries. From each population, 100 men and 100 women aged 50-54 years were randomly selected for BP measurement, 24-h urine collection, and blood test. Various biological markers of diets from urine and blood were analyzed centrally in the Izumo CARDIAC center. In within-center multiple regression analyses, body mass index (BMI) was strongly positively and independently associated with BP. Urine magnesium (Mg) excretion was negatively and independently associated with BP. In cross-center simple regression analyses, systolic and diastolic BP showed significant correlations with BMI (p less than 0.01) and 24-h urinary sodium (Na) excretion (p less than 0.005) in men and significant inverse correlations with urinary 3-methylhistidine (3-MH) divided by creatinine (p less than 0.01 and p less than 0.005, respectively) in men, and were inversely correlated with urinary Mg in women (p less than 0.05). Therefore, Na and BMI adversely affect BP, whereas animal protein and Mg intakes may have beneficial influence on BP.

Amino Acids↗
PubMed1990

Blood pressure levels in the elderly with or without nutritional intervention.

Blood pressure (BP) examination and urine analyses for the assessment of dietary Na, K, and protein intakes were carried out according to the standardized methods for the World Health Organization Cardiovascular Diseases and Alimentary Comparison Study in aged people with or without a longlasting nutritional intervention. Nutritional intervention to reduce salt intake and increase K and protein intakes was effective for BP reduction even in aged people over 65 years.

Aged↗
PubMed1989

A new view of the arterial smooth muscle cells and autonomic nerve plexus by scanning electron microscopy in spontaneously hypertensive rats.

Mesenteric artery smooth muscle cells and their associated autonomic nerve plexus were simultaneously studied by scanning electron microscopy in 3-month-old spontaneously hypertensive rats. The adventitial surface of the outermost muscle layer revealed numerically more protrusions accompanied by a denser network of nerve fibers in spontaneously hypertensive rats vs normotensive Wistar-Kyoto rats.

Animals↗
PubMed1988

Effects of low-dose chronic diltiazem treatment on hemodynamic changes in spontaneously hypertensive rats.

The effects of long-term diltiazem treatment on hemodynamic and cardiovascular characteristics were investigated in young spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY) and their respective untreated controls. The drug was administered to treated rats over a period of 24 weeks. Body weight, left ventricular weight, mean arterial pressure (MAP), heart rate, max dp/dt or maximum velocity of the contractile element (Vmax) were not significantly different in diltiazem-treated SHR and untreated SHR. In diltiazem-treated SHR, cardiac index (CI) and stroke volume index (SI) were significantly increased and total peripheral resistance and the index of left ventricular compliance (delta P/delta V) were significantly decreased compared with untreated SHR. Left ventricular pumping ability in treated SHR was higher than that in untreated SHR, despite the low dose of diltiazem given. However, there was no significant difference between treated and untreated WKY. Long-term diltiazem treatment did not affect left ventricular function or biochemical properties in SHR and WKY. These data suggest that long-term diltiazem treatment improves pump function in SHR without changing blood pressure.

Animals↗
PubMed1988

A new approach to the prevention of hypertensive cardiovascular diseases by controlling the proliferation of vascular smooth muscle cells.

Cholera toxin subunit B suppressed the proliferation of cultured vascular smooth muscle cells from the thoracic aorta of Wistar-Kyoto rats (WKY), stroke-resistant spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP). Since cholera toxin subunit B did not stimulate cyclic AMP accumulation in vascular smooth muscle cells, the effect of cholera toxin subunit B might be due to another mechanism. Cholera toxin subunit B bound to the surface of vascular smooth muscle cells and was rapidly incorporated into them. The morphological structure of vascular smooth muscle cells was transformed from the synthetic type to the non-synthetic type, in which microfilaments and intermediate filaments were abundantly formed, while rough endoplasmic reticulum was decreased after CTB treatment.

Animals↗
PubMed1987

Effect of milk protein and fat intake on blood pressure and the incidence of cerebrovascular diseases in stroke-prone spontaneously hypertensive rats (SHRSP).

The intake of two milk protein-rich diets containing casein and whey protein attenuated the development of severe hypertension in stroke-prone spontaneously hypertensive rats (SHRSP), and extended their life span in comparison with SHRSP on a regular stock diet. Milk fat-rich diet intake reduced the incidence of cerebrovascular disease in SHRSP without a significant fall in blood pressure. These results suggest that certain milk components have a preventive effect on hypertension and cerebrovascular disease in SHRSP.

Animals↗
PubMed1987

Effects of sulphur amino acids on the development of hypertension and atherosclerosis in stroke-prone spontaneously hypertensive rats.

We investigated the effects on blood pressure of 5% taurine administered prenatally or postnatally via maternal parents in stroke-prone spontaneously hypertensive rats (SHRSP). Prenatal and/or postnatal administration of taurine produced a blood pressure reduction in the offspring until at least 3 months of age. Furthermore, offspring exposed to high concentrations of taurine through the placenta during the prenatal period and also for 1 month after birth via maternal milk, showed a greater reduction in blood pressure than the group given taurine prenatally but not postnatally. The stroke-prone SHR were fed a high-fat cholesterol and low-protein diet containing 1% methionine or with 3% lysine in drinking water, and effects of the dietary amino acids on the development of atherogenesis were investigated. Intake of additional 1% methionine or 3% lysine had marked preventive effects on atherogenesis in the cerebral and mesenteric arteries in SHRSP. Therefore, early dietary intake of sulphur amino acids delays the onset of hypertension and attenuates the development of both severe hypertension and atherosclerosis in SHRSP.

Animals↗
PubMed1987

Catecholamine-induced polyploidization in vascular smooth muscle cells.

Polyploidy formation of vascular smooth muscle cells was observed in vivo by intravenous infusion of norepinephrine or epinephrine in Wistar-Crea rats for 12 days at the rate of 0.02 mumol/hr with an osmotic minipump and in vitro by exposing cultured vascular smooth muscle cells obtained from normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) to norepinephrine (10(-7)M to 10(-5)M) in the cultured medium. Infusion in vivo of norepinephrine but not epinephrine increased blood pressure slightly. However, both agents increased significantly the frequency of tetraploidy of smooth muscle cells up to 14.9 +/- 0.6% (mean +/- SE) and 9.2 +/- 0.5% compared with saline (6.5 +/- 0.7%). Exposure in vitro to norepinephrine (10(-6)M) increased the frequency of tetraploidy and octaploidy of smooth muscle cells from SHR up to 14.2% and 2.1%, respectively, compared with nonexposed cells (8.1% and 0.2%). These results appear to indicate that norepinephrine and epinephrine induce polyploidy of smooth muscle cells independently from blood pressure elevation.

Animals↗
PubMed1986

Dietary prevention of stroke and its mechanisms in stroke-prone spontaneously hypertensive rats--preventive effect of dietary fibre and palmitoleic acid.

Previously it was reported that dietary protein, some amino acids and potassium are effective in preventing stroke in stroke-prone spontaneously hypertensive rats (SHRSP). The present study revealed that other dietary factors could also prevent cerebral lesions, and the mechanism of this effect was studied. In SHRSP given 1% NaCl in their drinking water, a diet containing 10% active fibre (powdered brown seaweed converted to K+ form) significantly lowered blood pressure (BP) and markedly reduced the incidence of stroke (0 versus 100% in controls on the 30th day of experiment). Since the faecal to urinary sodium (Na) excretion ratio was increased in this group and a similar increase in faecal Na content was noted in SHRSP given a diet containing 10% alginic acid, the inhibition of intestinal Na absorption by alginic acid in the seaweed fibre was considered to be a possible preventive mechanism. Among SHRSP given various fatty acids, a diet containing 1% palmitoleic acid (POA) significantly improved the survival rate, with concomitant reduction in the incidence of stroke in spite of their excess NaCl intake through 1% NaCl water for drinking. Since neither BP nor urinary Na excretion was changed by POA which had high affinity for the vascular wall, the preventive effect was ascribed to the possible direct metabolic improvement of vascular smooth muscle cells.

Alginates↗
PubMed1986

Comparison of various genetic hypertensive rat strains.

Comparative studies on nine genetic hypertensive rat strains [two stroke-prone spontaneously hypertensive rats (SHRSP) and Dahl salt-sensitive (DS) strains, and one strain each of spontaneously hypertensive rats (SHR), Lyon hypertensive rats (LH), Milan hypertensive strain (MHS), genetically hypertensive rats (GH) and Sabra hypertensive rats (SBH)] and their respective controls [two Dahl salt-resistent (DR) strains and one strain each of Wistar-Kyoto rats (WKY), Lyon normotensive rats (LN); Lyon low blood pressure rats (LL), Milan normotensive strain (MNS), genetically normotensive rats (GN) and Sabra normotensive rats (SBN) and their original strain, Sabra rats (SB)], in groups consisting of 6-10 males from each strain, were carried out at 10-12 weeks of age under the same experimental conditions. After checking the developmental course of blood pressure and changes in body weight, they were killed at 12 weeks of age for blood analysis and organ-weight examinations. The SHRSP and SHR showed markedly higher blood pressure levels and earlier blood pressure rises in comparison with other hypertensive strains, although they had higher blood pressure than their respective controls. Among various organ weights examined, all hypertensive strains commonly showed increases in left ventricular weight in proportion to blood pressure rises. Kidney weights were significantly decreased only in MHS compared with MNS, while they were either unchanged or significantly greater in other hypertensive strains. Weights of adrenal glands were greater in the two strains of DS and in LH than in their respective control strains. These comparative data indicate possible differences in the pathogenic mechanism involved in these genetic hypertensive rat strains.

Animals↗