Search PubMed⌕ Search

Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 631 records · Page 35Linked to original sources

Effects of calcitonin gene-related peptide on canine cerebral artery strips and the in-vivo vertebral blood flow in dogs.

The effects of calcitonin gene-related peptide (CGRP) on canine cerebral arteries and on vertebral blood flow were investigated in-vivo and in-vitro and the findings compared with the effects of vasoactive intestinal peptide (VIP) and substance P. Administration of CGRP into the vertebral artery caused a dose-dependent and long-lasting increase in blood flow. The in-vivo vasodilatory effects of substance P and VIP were short-lasting. CGRP (0.1 to 100 nmol/l) elicited a concentration-dependent relaxation of the isolated middle cerebral and basilar arteries when the tissues were precontracted by exposure to prostaglandin F2 alpha (PGF2 alpha). This effect was not antagonized by propranolol, atropine, tetrodotoxin, (N-Ac-Tyr1, D-Phe2)-growth hormone-releasing factor(1-29)-NH2 or (D-Pro2, D-Trp7,9) substance P. CGRP also reduced concentration-dependently the contraction of cerebral arteries induced by KCl or 9,11-epithio-11,12-metano-thromboxane A2 (STXA2). Mechanical removal of the endothelium did not abolish the vasodilatory response to CGRP. In PGF2 alpha-contracted canine cerebral arteries, VIP (0.1 to 100 nmol/l) was less potent a vasodilator than CGRP. At low concentrations (0.01 to 1 nmol/l) substance P elicited a rapid and short-lasting relaxation, and in the absence of endothelium this relaxation disappeared. These findings are clear evidence that CGRP modulates vascular tone.

Animals↗

Developmental characteristics of fetal arrhythmias during the period from intrauterine to early extrauterine life assessed using dual echocardiography.

To evaluate the outcome of fetal arrhythmias, serial echocardiographic examinations were made on 29 fetuses between 18 and 41 weeks gestation, including 23 with premature contractions (PCs) and 6 with complete atrioventricular block (AVB). Of the cases of PCs 43.5% (10/23) disappeared spontaneously during the antenatal period. 39.1% (9/23) converted to a normal sinus rhythm in early neonatal life, while 17.4% (4/23) had complications of either atrial or ventricular tachycardia. All with AVB (6/6) remained, regardless of advance in gestational age and continued through to the postnatal period. PCs and AVB indicate functional error and an impairment during development of the conduction system, respectively.

Arrhythmias, Cardiac↗

2-Bromo- and 16-bromo-estrogens and related compounds: potential inhibitors for both estradiol 2- and 16 alpha-hydroxylases in rat liver microsomes.

Kinetic studies of inhibition of estradiol 2- and 16 alpha-hydroxylase activities in male rat liver microsomes with 2-bromoestrogens, 4-bromo-estrone (4-BrE1), 16 alpha- and 16 beta-bromoestrones and 16 beta-acetylthioestrone (16-AcSE1) were carried out. 2-Bromoestrogens and 4-BrE1 nonspecifically blocked the two enzyme activities in a competitive manner, and 2-bromo-estradiol (2-BrE2) was the most potent inhibitor for the two hydroxylases among the 2- and 4-bromo steroids. Kinetic data, the apparent Ki's for the inhibitors and the apparent Km's for the substrate E2 in the assay, demonstrate that the A-ring bromo steroids are potent inhibitors for the two enzymes (Ki/Km ranging from 0.28 to 0.48 for the 2-hydroxylation and ranging from 0.26 to 0.49 for the 16 alpha-hydroxylation). In contrast, 16-bromoestrones and 16-AcSE1 non-competitively inhibited the 2-hydroxylation (Ki = ca. 70 microM) while the other was competitively blocked by them (Ki/Km ranging from 0.24 to 0.30). These 16-substituted steroids were very potent inhibitors for the 16 alpha-hydroxylase rather than the 2-hydroxylase and preferentially blocked the former.

Animals↗

Changes in vascular resistance in the umbilical and middle cerebral arteries in the human intrauterine growth-retarded fetus, measured with pulsed Doppler ultrasound.

To assess how different cardiotocographic (CTG) findings are related to changes in vascular resistance, 256 normal and 37 growth retarded (IUGR) fetuses from 27 to 41 weeks of gestation were studied. Immediately following CTG monitoring, pulsed Doppler was used to identify flow velocity waveforms in both the middle cerebral artery (MCA) and the umbilical artery (UA), and from these the Resistance Indices (RIs) in both arteries (RIMCA and RIUA) were calculated. Of the 37 growth retarded fetuses, 25 had normal CTG findings. Although only 3 (12.0%) of these fetuses had low RIMCA, 12 (48.0%) had high RIUA, statistically different (P less than 0.01) from normal fetuses. In 11 of 12 (91.7%) growth retarded fetuses with an abnormal CTG, there were low RIMCA values, significantly more (P less than 0.01) than in those with a normal CTG. As for RIUA, all 12 IUGR fetuses with an abnormal CTG had high RIUA values (100%), a much higher proportion (P less than 0.01) than was found in the normal CTG group. These results mean that intrauterine fetal growth retardation per se is associated with a chronic increase in the RI value in the umbilical artery. By contrast, cerebral vascular resistance appears to decrease in compromised conditions, as indicated by abnormal CTG findings.

Blood Flow Velocity↗

Effects of neuropeptide Y and calcitonin gene-related peptide on local cerebral blood flow in rat striatum.

The effects of neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) on local cerebral blood flow (LCBF) were studied in vivo in rat striatum. Administration of 1 and 5 nmol NPY as a bolus into the internal carotid artery caused a dose-dependent decrease in the ipsilateral striatal LCBF. This decrease developed slowly and persisted for at least 2 h, without affecting mean blood pressure. In contrast, CGRP, at a concentration of 10 pmol, increased striatal LCBF by about 30%, and the duration of the increase was about 1 h. However, at higher doses of CGRP no increase in LCBF was observed. These results suggest that NPY and CGRP released from nerve fibers innervating blood vessels can function as long-acting modulators of CBF.

Animals↗

The effect of food deprivation on the fatty acid and lipid profile of red seabream (Pagrus major) larvae.

Under conditions of food deprivation the lipid fraction of red seabream (Pagrus major) larvae shows patterns of conservation or loss in the profile of fatty acids and lipids. These changes were used for qualitative formulation of the dietary requirements of this species. Red seabream larvae were deprived of food for 5 d after hatching. Their lipid was extracted, weighed and analysed by gas-liquid chromatography and iatroscan for the presence of twenty-four fatty acids including n-3 polyunsaturated fatty acids (PUFA), four polar lipids (PL) and four neutral lipids (NL). The results show an exponential decline in lipids with food deprivation, from a mean of 27.7 down to 11.8 mg/g wet larvae weight (LW). This loss could mainly be attributed to a decline in NL from 22.4 to 7.7 mg/g LW, in triacylglycerols, from 21 to 1 mg/g LW, and a change in cholesterol, from 1.3 to 4.2 mg/g LW after 5 d of food deprivation. PL declined from 5.3 to 4.1 mg/g LW in this period. The chief components of this fraction were phosphatidyl choline, and phosphatidyl ethanolamine. Among the fatty acids, the chief decline was observed in saturates and monoenes. Carbon chain lengths of 14 to 18 made up 18.2 mg/g LW in hatched larvae, but only 4.8 mg/g LW in larvae which were deprived of food for 5 d after hatching. n-3 PUFA were lost at a slower rate, from 5.4 to 3.5 mg/g LW for the same period, suggesting that they were conserved. Finally, early larvae of red seabream showed a reduced rate of loss of n-6 relative to n-9 fatty acids, suggesting that the latter were used preferentially as an energy source.

Animals↗

Effect of dietary n-3 fatty acids on weight gain and liver polar lipid fatty acid composition of fingerling channel catfish.

A 10-wk experiment was conducted to determine the effect of supplementing a 5% tristearin basal diet with linoleic acid [18:2(n-6)], linolenic acid [18:3(n-3)], an n-3 highly unsaturated fatty acid (n-3 HUFA) mixture, cod liver oil, corn oil or linseed oil on growth and fatty acid composition of the liver polar lipid fraction of fingerling channel catfish (Ictalurus punctatus). The lowest weight gain was observed in fish fed the basal diet. Weight gain was improved by certain levels of supplemental n-3 fatty acids. Fish fed a diet containing 2% 18:3(n-3) grew at the same rate as fish fed a diet containing 2.5% cod liver oil plus 2.5% corn oil. The best growth rate was observed in fish fed diets containing either 5% cod liver oil or 5% linseed oil. Growth rate was depressed by supplementation with 4% 18:3(n-3) or 1.25% n-3 HUFA mix. No improvement in growth rate was observed with dietary 18:2(n-6). Dietary linolenate was converted to docosahexaenoic acid [22:6(n-3)]. The ratio of 20:3(n-9) to 22:6(n-3) of the fish showing good growth was less than 0.4. The data obtained in this experiment indicate that n-3 fatty acids are essential for channel catfish and that the 18:3(n-3) or n-3 HUFA dietary requirement is 1.0-2.0% or 0.5-0.75%, respectively.

Animals↗

Inactivation of 1-Aminocyclopropane-1-Carboxylate Synthase by l-Vinylglycine as Related to the Mechanism-Based Inactivation of the Enzyme by S-Adenosyl-l-Methionine.

The pyridoxal phosphate-dependent 1-aminocyclopropane-1-carboxylate (ACC) synthase catalyzes the conversion of S-adenosyl-l-methionine (AdoMet) to ACC, and is inactivated by AdoMet during the reaction. l-Vinylglycine was found to be a competitive inhibitor of the enzyme, and to cause a time-dependent inactivation of the enzyme. The inactivation required the presence of pyridoxal phosphate and followed pseudo-first-order kinetics at various concentrations of l-vinylglycine. The Michaelis constant for l-vinylglycine in the inactivation reaction (K(inact)) was 3.3 millimolar and the maximum rate constant (k(max)) was 0.1 per minute. These findings, coupled with the previous observations that the suicidal action of AdoMet involved a covalent linkage of the aminobutyrate portion of AdoMet to the enzyme, support the view that the mechanism-based inactivation of ACC synthase by the substrate AdoMet proceeds through the formation of a vinylglycine-ACC synthase complex as an intermediate.

Journal Article↗

Sensitivity of arterial baroreflex changes during daily activity.

1. Continuous ambulatory arterial pressure monitoring was performed by telemetry in 34 hypertensive and four normotensive subjects and arterial baroreflex sensitivity was evaluated by computer analysis of pulse wave. Three consecutive pulses were selected, on two criteria, from the 24 h recording: (i) progressive and linear increase or decrease in systolic arterial pressure and heart period, (ii) change of systolic arterial pressure in three pulses exceeds a threshold value. The systolic arterial pressure and heart period of three pulses were averaged and the slopes of systolic arterial pressure and heart period were calculated as baroreflex sensitivity. 2. When the threshold value was set to 5 mmHg, baroreflex sensitivity measured by the present method correlated with baroreflex sensitivity as measured by the phenylephrine method (r = 0.667, P less than 0.001). 3. The baroreflex sensitivity from the pressor-bradycardia and the depressor-tachycardia reflex decreased as threshold value was increased from 3 to 4 mmHg to over 20 mmHg. With the pressor-bradycardia reflex, the initial systolic arterial pressure of three pulses did not change, but the initial heart period shortened progressively as the threshold increased. With the depressor-tachycardia reflex, the initial systolic arterial pressure increased and the initial heart period shortened progressively. This suggests that the sensitivity of arterial baroreflex changes dynamically according to input of reflex are during daily activity.

Adult↗

Vasodilator actions of HA1077 in vitro and in vivo putatively mediated by the inhibition of protein kinase.

The in vitro and in vivo vasorelaxant effects of HA1077, 1-(5-isoquinolinesulphonyl)-homopiperazine HCl, a novel vasodilator were examined. The inhibitory effects of HA1077 on contractile responses to various agonists were examined on strips of rabbit aorta. The concentration-response curves to 5-hydroxytryptamine, prostaglandin F2alpha, histamine, angiotensin II, noradrenaline and dopamine were concentration-dependently shifted to the right in the presence of HA1077 (0.3-3.0 microM). The in vivo vasodilator effects of HA1077 were examined in the constant-pressure autoperfused coronary vascular bed of dogs. Intra-coronary administration of HA1077 (3-30 micrograms per dog) dose-dependently increased coronary blood flow (CBF), with no effect on mean blood pressure (MBP) or heart rate (HR). Intra-coronary infusion of atropine, propranolol or diphenhydramine did not modify the in vivo coronary vasodilator response to HA1077. To determine the flow profile for HA1077 in dogs, blood flow in four vascular beds was measured, by use of noncannulating electromagnetic flow probes. HA1077 (0.01-0.3 mg kg-1, i.v.) dose-dependently decreased MBP and increased vertebral blood flow (VBF), CBF, renal blood flow (RBF) and femoral blood flow (FBF). A haemodynamic analysis showed that continuous i.v. infusion of HA1077 (0.01 and 0.033 mg kg-1min-1) dose-dependently decreased peripheral vascular resistance and increased cardiac output. There were no significant changes in right atrial pressure, dP/dt or ventricular minute work. The effects of HA1077 on various enzymes considered to be related to the regulation of smooth muscle contraction were examined. HA1077 had little effect on cyclic nucleotide phosphodiesterases, yet it potently inhibited protein kinases such as cyclic nucleotide dependent protein kinases and Ca2+/calmodulin dependent myosin light chain kinase. The present study demonstrates that HA1077 is a novel type of arterial vasodilator.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

Atrial natriuretic factor suppresses neural stimulation of renin release in dogs.

The effects of atrial natriuretic factor (ANF) on neural control of renin release and sodium excretion by the kidney were examined in pentobarbital-anesthetized dogs. Electrical stimulation of the renal nerves (RNS, 1 Hz) increased the renal secretion rate of renin (RSR) by 627 +/- 141 ng angiotensin I (ANG I)/min and that of norepinephrine (NESR) by 22.2 +/- 5.9 ng/min. Furthermore, urinary sodium excretion (UNaV) was decreased by 59 +/- 7%, with little change in either renal blood flow (RBF) or glomerular filtration rate (GFR). Intrarenal arterial infusion of ANF (alpha-human atrial natriuretic peptide; 10 ng.kg-1.min-1) increased basal UNaV about twofold but had no effect on basal RBF or GFR. The RNS-induced increase in RSR during ANF infusion (198 +/- 117 ng ANG I/min) was significantly lower than that before the infusion (P less than 0.05), whereas the RNS-induced changes in NESR (27.1 +/- 8.5 ng/min) and UNaV (51 +/- 11%) were unaffected. These results suggest that neural stimulation of renin release, but not of tubular sodium reabsorption, can be suppressed by exogenously administered ANF at a dose that does not affect glomerular filtration or renal neurotransmitter release.

Animals↗

Prostatic epithelial polyp of the prostatic urethra.

Ten cases of prostatic epithelial polyps of the prostatic urethra are reported. The ages of the patients were from 27 to 69 years, with a mean of 44 years. The most common clinical signs were gross hematuria, microhematuria, hematospermia, and dysuria. All specimens, obtained by transurethral resection, had a papillary or polypoid configuration. The tissue had a glandular structure that resembled that of the prostate. Prostate-specific antigen and prostatic acid phosphatase were found in the epithelial cells of the polyps by indirect immunoperoxidase staining. The polyps seemed to be hyperplasia of prostate-specific antigen and prostatic acid phosphatase-positive epithelial cells of the prostatic gland or duct, especially that of the latter.

Adult↗

Relaxation of airway smooth muscle induced by potassium in the presence of Ca-antagonists.

We examined K+-induced relaxation instead of contraction in the presence of Ca-antagonists by measuring isometric tension in the tracheal smooth muscle isolated from guinea pigs. Cumulative administration of KCl (10-90 mM) induced a concentration-dependent contraction. When the muscle was pretreated with low concentrations of Ca-antagonists, cumulative administration of KCl caused a mild contraction, followed by a moderate relaxation. In the muscle pretreated with high concentrations of Ca-antagonists, KCl revealed a concentration-related relaxation without contraction. The potency ratios of Ca-antagonists to reverse the KCl-induced contraction to relaxation were nifedipine : verapamil : diltiazem = 94:4:1. This order of potency was quite similar to that of Ca-antagonists to relax the muscle precontracted with KCl (30 mM). Magnitudes of KCl (30 m,)-induced relaxation in the presence of Ca-antagonists were similar to those caused by Ca-antagonists in the KCl (30 mM)-precontracted muscles. Thus, K+-induced relaxation in the airway smooth muscle in the presence of Ca-antagonists may be due to the voltage-dependent increase in binding of Ca-antagonists to calcium channels.

Animals↗

Actions of a newly synthesized nitro-compound, E-4701, on rabbit vascular smooth muscles.

The effects of a newly synthesized water soluble and light resistant nitro-compound, E-4701, on the electrical and mechanical properties of smooth muscle cells of rabbit mesenteric and coronary arteries were investigated. In the endothelium-denuded rabbit mesenteric artery, E-4701 relaxed the tissue pre-contracted by noradrenaline (IC50 = 40 microM) to a greater extent than that contracted by high K, but to a lesser extent than that contracted by acetylcholine (ACh) or high K in endothelium-denuded rabbit coronary artery (the IC50 was 20 nM or 60 nM, respectively). Nitroglycerin showed much the same relaxing action on the above tissue (IC50 for the ACh- or K-induced contraction was 20 nM or 65 nM, respectively). Relaxing actions of E-4701 or nitroglycerin were prevented by 10 microM methylene blue. In muscle cells of the porcine coronary artery, E-4701 or nitroglycerin inhibited the Ca-transient provoked by ACh, as examined using fura-2. Both drugs had no effect on the Ca-induced contraction in skinned muscle strips. ACh produced a transient hyperpolarization with subsequent depolarization, but in the endothelium-denuded tissues. ACh only depolarized the membrane. E-4701 inhibited the ACh-induced depolarization, but nitroglycerin did not. We concluded from our observations that E-4701 has the typical characteristics of a nitrocompound with an inhibitory action on the agonist-induced membrane depolarization.

Acetylcholine↗

Vitamin K-reversible hypoprothrombinemia in rats: comparison of hypoprothrombinemic changes in various strains of rats caused by vitamin K deficiency and antibiotic treatment.

Hypoprothrombinemic changes were compared in rats fed various vitamin K-deficient diets. Changes such as prolongation of prothrombin time and activated partial thromboplastin time, decrease in plasma levels of prothrombin and clotting factor VII, and increase in plasma descarboxyprothrombin, appeared in rats maintained on vitamin K-deficient diet, but in rats on ordinary diet (vitamin K-sufficient diet). As the development of hypoprothrombinemia was not significantly different among animals fed various vitamin K-deficient diets, the blood coagulation parameters were concluded to be regulated only by the vitamin K level. Following the development of hypoprothrombinemia, hemorrhaging in various organs was detected in vitamin K-deficient rats, with strain differences in the severity of hemorrhage; Fischer and Wistar strains were more sensitive than the Sprague Dawley strain. Administration of a beta-lactam antibiotic, latamoxef (LMOX), to vitamin K-deficient rats led to enhancement of the hypoprothrombinemic conditions, but LMOX-associated changes in plasma enzyme levels were not detected.

Animals↗

Cerebral blood flow in patients with putaminal hemorrhage after stereotactic aspiration or conservative treatment.

Changes in cerebral blood flow (CBF) were measured and compared in 40 patients with putaminal hemorrhage who underwent either stereotactic hematoma aspiration or conservative treatment. There were no statistically significant differences in mean CBF or hemispheric CBF between the two treatment groups. Although there are claims of the superiority of surgery from the standpoint of integrated cortical function following mild putaminal hemorrhage, the results of this investigation indicate that conservative therapy is adequate in such cases, based on improvement in CBF.

Adult↗

Occipital lobe ependymal cyst--case report.

A 51-year-old female with an ependymal cyst in the left occipital lobe presented with headache, vomiting, dizziness, and right incomplete homonymous hemianopsia. Following a cyst-ventricular communication and cyst-peritoneal shunting procedure, the visual field loss improved markedly. On the basis of the visual field symptoms, computed tomographic findings, and intraoperative observations, the cyst was considered to have developed in the vicinity of the body and posterior horn of the left lateral ventricle, extending to the left occipital lobe.

Brain Diseases↗