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Biomedical subjects

K Matsui

Publications and source records attributed to K Matsui.

At least 559 records · Page 31Linked to original sources
PubMed1986

Characterization of a vasopressor substance generated in human plasma by incubation.

Incubation of human plasma at 37 degrees C for several hours leads to the formation of a non-dialysable vasopressor substance termed the active pressor principle. Some of the chemical and physical natures of active pressor principle were investigated in anesthetized and ganglion blocked rats. It was found to have properties characteristic of protein. The substance was crudely purified to about 25-fold in alcoholic trichloroacetic acid solution after placing the plasma in a boiling water bath for 5 minutes ("active fraction"). After treatment of the vasoactive plasma or "active fraction" with Pronase, the pressor activity was almost abolished. The molecular weight of this fraction as determined by gel filtration was about 68,000. With addition of diisopropyl fluorophosphate before incubation of the plasma, no vasopressor substance was generated. After treatment of the rat with captopril, an angiotensin converting enzyme inhibitor, the pressor effect of incubated plasma was not inhibited. These findings suggest that a vasoactive protein, which is clearly different from renin, is generated during simple incubation of plasma, and that a serine protease is involved in the formation of this substance.

Angiotensin I↗
PubMed1986

Anti-platelet action of an anti-allergic agent, N-(3',4'-dimethoxycinnamoyl)anthranilic acid (tranilast).

The effects of N-(3',4'-dimethoxycinnamoyl)anthranilic acid (Tranilast), a blocker for histamine release from mast cells, on rabbit blood platelet functions were investigated. Tranilast inhibited dose dependently both the release of a lysozomal enzyme, beta-N-acetylglucosaminidase, and aggregation of washed rabbit platelets stimulated by thrombin and collagen. The IC50 was suspected to be 164 +/- 50 microM. The data suggest that Tranilast may be used as an anti-platelet agent in addition to an anti-allergic one.

Acetylglucosaminidase↗
PubMed1986

Vasopressor activity in incubated plasma of normal and hypertensive pregnant women.

The pressor activity generated in incubated plasma of nonpregnant, normal pregnant, and hypertensive pregnant women was measured by means of a sensitive bioassay technique. It was found that the plasma of normal pregnant women generated significantly higher amounts of active pressor principle than the plasma of nonpregnant women. The plasma of hypertensive pregnant women generated significantly lower amounts of active pressor principle than the plasma of normal pregnant women. Plasma obtained from the antecubital vein revealed no difference in pressor activity compared to plasma collected from the uterine vein at the time of cesarean section. These data suggest that active pressor principle is not involved in the pathogenesis of pregnancy-induced hypertension and that the pregnant uterus is not the source of active pressor principle.

Angiotensin II↗
PubMed1986

Craniofacial defects associated with amniotic band syndrome: a case report.

A pathological study was made of a female infant with amniotic band syndrome. At birth, the 1450-g female infant was noted to have craniofacial defects such as anencephaly, cleft lip, severe nasal deformity and asymmetric microphthalmia. The fetal membrane was focally adhered to the scalp, and histological examinations revealed that the connecting area of the fetal head to the membrane resembled a serial architecture from keratinized squamous cells to amniotic layer without any inflammatory findings. These observations suggested that the etiology in the present case may be consistent with Torpin's mesodermic band theory.

Abnormalities, Multiple↗
PubMed1986

Fetal heart monitoring and ultrasound in the management of placental abruption.

Three cases of placental abruption with the "pseudosinusoidal" fetal heart rate (FHR) pattern, a periodic late deceleration related to frequent uterine contractions are reported. This 'pseudosinusoidal' pattern is clearly not a true sinusoidal pattern. The fetal monitoring patterns of these patients are presented and discussed along with the use of ultrasound in the management of this condition. All infants were delivered by cesarean section with low Apgar scores at birth, but they soon recovered completely.

Abruptio Placentae↗
PubMed1986

Effects of highly purified eicosapentaenoic acid on vascular reactivity to angiotensin II and norepinephrine in the rabbit.

There is disagreement about whether supplementation of the diet with fish oil, which is rich in eicosapentaenoic acid (EPA), lowers blood pressure. We gave highly purified EPA in a soft capsule (90% ethyl ester form of EPA; EPA-E), to female rabbits (100 mg/kg/day) for 4 weeks. Vascular response to vasoconstrictor agents was assessed serially by measuring the systolic blood pressure using a Grand-Rothschild capsule in the ear. There was no change in systolic blood pressure of rabbits treated with EPA-E, but rabbits given EPA-E for one week or longer were significantly less responsive to the pressor effects of angiotensin II than the controls. Responses to norepinephrine did not change. Rabbits given EPA-E for four weeks had significantly more EPA in the serum, but there were no differences in serum levels of triglycerides, total cholesterol, or high-density lipoprotein cholesterol. These results suggest that vascular responses to exogenous angiotensin II can be selectively depressed by short-term treatment with EPA-E in rabbits without changing systolic blood pressure.

Angiotensin II↗
PubMed1986

Synthesis and alpha-D-glucosidase inhibitory activity of N-substituted valiolamine derivatives as potential oral antidiabetic agents.

Various kinds of N-substituted valiolamine derivatives, including compounds 23a, 24a, and 34a, which are structurally analogous to the key pseudodisaccharides (25a and 26a) of naturally occurring oligosaccharide alpha-D-glucosidase inhibitors, have been synthesized and estimated by the measure of inhibitory activity against porcine sucrase and maltase. The N-substituted valiolamine derivatives evaluated in this study have been found to be more potent than the corresponding N-substituted valienamine derivatives as well as the parent valiolamine. It is noteworthy that even simple N-substituted valiolamine derivatives such as N-[2-hydroxy-1-(hydroxymethyl)ethyl]-, N-[(1R,2R)-2-hydroxycyclohexyl]-, and N-[(R)-(-)-beta-hydroxyphenethyl]valiolamine (6, 8a, and 9a) have the stronger alpha-D-glucosidase inhibitory activity against porcine intestinal maltase and sucrase than naturally occurring oligosaccharide alpha-D-glucosidase inhibitors.

Animals↗
PubMed1986

Purification and properties of glucoside 3-dehydrogenase from Flavobacterium saccharophilum.

A membrane-bound glucoside 3-dehydrogenase [EC 1.1.99.13], which oxidizes validoxylamine A to the 3-keto derivative, was solubilized from the membrane fraction of Flavobacterium saccharophilum by Triton X-100 and purified about 280-fold with an overall yield of 30% from the membrane fraction by column chromatography on DEAE- and CM-Sepharose CL-6B and gel filtration on Sephacryl S-300. The purified enzyme exhibited a single protein band on disc gel electrophoresis, and FAD was shown to be the prosthetic group. The enzyme had a molecular weight of 270,000 as determined by gel filtration on Sephacryl S-300 and consisted of 4 identical subunits each with a molecular weight of 66,000. The enzyme reacted with various artificial electron acceptors such as 2,6-dichlorophenolindophenol (DCIP), phenazine methosulfate, and ferricyanide. The optimum pH for DCIP reductase activity was 6.0. The enzyme was inhibited by Hg2+ and p-chloromercuribenzoate. D-Glucose and methyl-alpha- and beta-D-glucoside showed the highest susceptibility to the enzyme, and were converted to the corresponding 3-keto sugars.

Carbohydrate Dehydrogenases↗
PubMed1986

Chemical modification by diethylpyrocarbonate of an essential histidine residue in 3-ketovalidoxylamine A C-N lyase.

3-Ketovalidoxylamine A C-N lyase of Flavobacterium saccharophilum is a monomeric protein with a molecular weight of 36,000. Amino acid analysis revealed that the enzyme contains 5 histidine residues and no cysteine residue. The enzyme was inactivated by diethylpyrocarbonate (DEP) following pseudo-first order kinetics. Upon treatment of the inactivated enzyme with hydroxylamine, the enzyme activity was completely restored. The difference absorption spectrum of the modified versus native enzyme exhibited a prominent peak around 240 nm, but there was no absorbance change above 270 nm. The pH-dependence of inactivation suggested the involvement of an amino acid residue having a pKa of 6.8. These results indicate that the inactivation is due to the modification of histidine residues. Substrates of the lyase, p-nitrophenyl-3-ketovalidamine, p-nitrophenyl-alpha-D-3-ketoglucoside, and methyl-alpha-D-3-ketoglucoside, protected the enzyme against the inactivation, suggesting that the modification occurred at or near the active site. Although several histidine residues were modified by DEP, a plot of log (reciprocal of the half-time of inactivation) versus log (concentration of DEP) suggested that one histidine residue has an essential role in catalysis.

Amino Acids↗
PubMed1986

The pharmacological effect of thyrotropin-releasing hormone on ataxic mutant mice.

The Rolling mouse Nagoya (RMN), Staggerer, Weaver and Reeler, all of which show hereditary ataxia, were intraperitoneally injected with 25 mg/kg of thyrotropin-releasing hormone (TRH-T) or physiological saline, and changes in the motions of these animals were observed by an Animex II and an open field method. All four strains of mice with ataxia showed improvement of ataxia and an increase in the motion volume, but these changes were not necessarily consistent in degree. Improvement of ataxia was most marked in the RMN and the Staggerer, moderate in the Weaver and slight in the Reeler, which showed enhanced tremor. The relationship between the competence of transmitting information in the cerebellum and improvement of ataxia by the injection of TRH-T aroused our interest.

Animals↗
PubMed1986

Effects of human atrial natriuretic peptide on renal function and vasopressin release.

To assess the effects of atrial natriuretic peptide (ANP) on the renal function, cardiovascular system, renin-angiotensin-aldosterone system, and vasopressin release, synthetic human ANP (alpha-hANP) was administered at a dose of 0.08 microgram X kg-1 X min-1 iv for 40 min into anesthetized dogs (n = 6). In the control study (n = 6), saline alone was infused. alpha-hANP brought about a significant increase in renal plasma flow, urinary Na and K output, urine flow, and osmolar clearance and a significant decrease in urinary osmolality, free water clearance, and filtration fraction (FF), with no changes in glomerular filtration rate. Plasma Na concentrations and osmolality did not change significantly, but plasma K concentrations fell progressively. Mean arterial blood pressure decreased without any changes in heart rate. Plasma renin activity (PRA), plasma aldosterone concentrations (PAC), and plasma vasopressin concentrations did not rise, but rather PRA and PAC tended to fall during alpha-hANP infusion. In the control study, there were no changes in these parameters except a progressive fall in FF and plasma K concentrations. These results indicate that the alpha-hANP-induced increase in renal blood flow plays an important role in producing natriuresis, but vasopressin may not be involved in the process of diuresis.

Aldosterone↗
PubMed1986

Role of intracerebral angiotensin receptors in the regulation of vasopressin release and the cardiovascular system.

In order to investigate the physiological role of the brain renin-angiotensin system in the regulation of vasopressin (ADH) release, angiotensin II (Ang II, 10 ng/kg/min) or 1-Sar-8-Ile-Ang II (50 ng/kg/min), an Ang II antagonist, was administered intracerebroventricularly to dogs (n = 42) anesthetized with urethane and chloralose after morphine sedation. The effects of the intravenous infusion of either 0.15 M or 2.5 M NaCl (0.1 ml/kg/min, 75 min) were also studied. In control dogs, artificial cerebrospinal fluid (ACSF) was administered at a rate of 10 microliter/min for 105 min. ACSF given intracerebroventricularly plus 0.15 M NaCl given intravenously did not affect ADH release, but 2.5 M NaCl given intravenously raised the plasma ADH level in parallel with the rise in plasma osmolality. Heart rate and blood pressure did not change significantly in ACSF along with 0.15 M NaCl, but heart rate increased significantly in ACSF along with 2.5 M NaCl. Ang II along with 0.15 M NaCl significantly raised plasma ADH and decreased heart rate without any changes in blood pressure. Ang II along with 2.5 M NaCl brought about a significant rise in plasma ADH level, arterial blood pressure, heart rate, and plasma osmolality. But simultaneous application of Ang II and 2.5 M NaCl did not result in a larger rise in plasma ADH than that expected from the effects of the two stimulations given separately. Namely, Ang II did not potentiate ADH release elicited by osmotic stimulation. Ang II antagonist given intracerebroventricularly neither affected ADH release and the cardiovascular system in 0.15 M NaCl nor inhibited ADH release in response to osmotic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1986

A Gc silent allele encountered in a paternity case.

A father-child incompatibility only in the Gc system was detected in a paternity case tested at our laboratory. Quantitative determination revealed that the Gc level in the two individuals was less than 50% of the normal mean value. Evaluation of the probability calculation for the putative father using all other markers showed that he was the biological father with a very high probability. Thus it was concluded that a silent allele Gc*QO was transmitted from the father to the child.

Alleles↗
PubMed1986

Effects of acute water load, hypertonic saline infusion, and furosemide administration on atrial natriuretic peptide and vasopressin release in humans.

A new specific RIA for alpha-human atrial natriuretic hormone (alpha hANP) was used to determine whether changes in plasma volume elicited by acute water loading, hypertonic saline infusion, and furosemide administration caused changes in ANP release and resultant changes in renal and cardiovascular function in normal subjects. In addition, changes in plasma arginine vasopressin (AVP), PRA, and aldosterone concentrations were studied simultaneously. Mean plasma alpha hANP and AVP levels were 51.3 +/- 16.0 (+/- SE) and 3.1 +/- 0.6 pg/ml, respectively, in the basal state. Plasma alpha hANP rose to 77.8 +/- 27.6 in response to a 4.5% increase in plasma volume induced by water loading, increased further to 134.1 +/- 28.9 in response to a 23% volume increase induced by hypertonic saline, and fell to 70.2 +/- 15.8 pg/ml in response to a decrease in plasma volume after furosemide treatment (P less than 0.01-0.05). On the other hand, plasma AVP fell to 1.8 +/- 0.1 pg/ml after the water load, rose to 4.1 +/- 0.6 after hypertonic saline, and rose further to 5.8 +/- 0.8 pg/ml after furosemide (P less than 0.01-0.05). Water and hypertonic saline loading decreased PRA, but plasma aldosterone concentrations did not change; subsequent furosemide administration increased both (P less than 0.01-0.05). Arterial pressure and heart rate did not change significantly. Increases in urinary Na excretion and osmolar clearances were associated with a rise in plasma alpha hANP after water loading and hypertonic saline infusion (P less than 0.01-0.05), but changes in urine flow were mainly associated with alterations in AVP release. associated with alterations in AVP release.

Adult↗
PubMed1986

Cardiotonic and coronary vasodilatatory effects of amrinone in the canine heart-lung preparation with a support dog as compared with those of dobutamine.

Analysis of the relative magnitude of the positive inotropic and chronotropic effects and the coronary vasodilating effects of amrinone conducted in the canine heart-lung preparation with a support dog in comparison with those of dobutamine demonstrated that amrinone was a preferential coronary vasodilator rather than a selective positive inotropic agent. An in vitro experiment in the canine papillary muscle suggested the initiation of the slow response action potential as a mechanism of the positive inotropic effect of amrinone.

Aminopyridines↗
PubMed1986

Assessment of the cardiohemodynamic effects of ibopamine, an orally-active dopamine analogue, in the anesthetized open-chest guinea pig and the isolated guinea pig atria.

In the anesthetized open-chest guinea pig, ibopamine (10-300 micrograms/kg, i.v.), epinine (10-100 micrograms/kg, i.v.) and dopamine (10-300 micrograms/kg, i.v.) produced dose-related increases in heart rate (prevented by 20 micrograms/kg pindolol, i.v.), left ventricular dP/dt max and aortic flow. Ibopamine produced pressor effects (prevented by 0.5 mg/kg phentolamine, i.v.), while dopamine produced a slight depressor effect. A biphasic response (the pressor phase followed by a depressor) was observed after epinine, although the depressor phase was not significant. Calculated total peripheral resistance (TPR) tended to be increased after ibopamine and epinine (initial phase), while it was decreased after dopamine. Pindolol potentiated the increase in TPR produced by ibopamine and epinine, while the increase in TPR was converted to the decrease after phentolamine. Decreases in TPR produced by epinine and the highest dose of dopamine were inhibited by pindolol. In the isolated guinea pig atria, ibopamine (10(-6)-10(-4) M) increased the atrial rate and the developed tension in a concentration-related manner. The positive chronotropic and inotropic effects of ibopamine were of the same order as those of epinine.

Animals↗