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Biomedical subjects

H Araki

Publications and source records attributed to H Araki.

At least 19 recordsLinked to original sources
PubMed1979

Protective action of 6-keto-prostaglandin E1 in traumatic shock.

Since prostaglandin E1 (PGE1) is known to have a beneficial effect in hemorrhagic shock, a biologically active derivative of PGE1, 6-keto-PGE1, was examined for its effect on traumatic shock in rats. In sham-operated rats, infusion of 6-keto-PGE1, at a rate of 250 ng/kg/min intravenously decreased arterial blood pressure by 23 mm Hg at 5 hr. In rats subjected to Noble-Collip drum trauma, infusion of 6-keto-PGE1, starting 15 min after the trauma, significantly improved the survival time from 1.0 +/- 0.1 to 2.6 +/- 0.3 hr compared to rats given only the vehicle (i.e., Tris buffer). The improved survival was accompanied by a diminished plasma accumulation of the cardiotoxic peptide, myocardial depressant factor (MDF), and the lysosomal protease cathepsin D. 6-keto-PGE1 also exerted a direct lysosomal stabilizing effect in isolated cat liver lysosomes, as well as reducing cardiac afterload in rats. It is concluded that 6-keto-PGE1 protects in traumatic shock by hemodynamic as well as cytoprotective actions.

Alprostadil↗
PubMed1979

Protective effects of a novel thromboxane analog in lethal traumatic shock.

Pinane thromboxane A2 (PTA2) an analog of thromboxane A2 that inhibits the formation of thromboxanes as well as antagonizes their biological actions, at an infusion rate of 1.0 mumole . kg-1 . h-1, prolonged survival in traumatic shock in rats. PTA2 also prevented the accumulation of thromboxane B2, the lysosomal protease, cathepsin D, and the cardiotoxic peptide MDF in the circulating blood.

Animals↗
PubMed1979

Effects of 2-nicotinamidoethyl nitrate (SG-75) on dog coronary artery and cat papillary muscle.

Effects of 2-nicotinamidoethyl nitrate (SG-75) on isolated dog coronary artery and cat papillary muscle were investigated. SG-75 dose-dependently relaxed the isolated coronary arterial strips contracted with potassium. Large doses of SG-75 depressed contraction of papillary muscle driven with electrical stimulation and inhibited enhancement of contraction of papillary muscle induced by calcium and isoproterenol. From these results it is suggested that SG-75 may have a weak Ca++-antagonistic action.

Animals↗
PubMed1979

Adriamycin instillation therapy for bladder tumors.

Topical instillation of Adriamycin, 40 mg in 20 ml sterilized distilled water, was performed in 20 cases of bladder tumors every day for two weeks. In 8 cases (40%) the tumors disappeared completely, while in 5 cases (25%) tumors were reduced in size, but in 7 cases (35%) there was no effect. Therefore, the rate of effectiveness was 65%. The local bladder reaction and urethral pain were noted in all cases, as a result of which the therapy was interrupted in 2 cases. Abnormal values of red blood cells, white blood cells and platelets were not observed. In 3 cases the serum level of Adriamycin was only trace 1 or 2 hr after instillation. In conclusion, Mitomycin C was thought to be superior to Adriamycin as far as the effectiveness and irritability on the normal bladder epithelium were concerned.

Administration, Topical↗
PubMed1979

Protective actions of aprotinin in acute traumatic shock.

The effect of the protease inhibitor, aprotinin, was examined in rats during traumatic shock. In sham-operated control rats, intravenous administration of aprotinin (20,000 or 40,000 KIU/kg) showed no immediate changes in the mean arterial blood pressure and heart rate. In rats subjected to Noble-Collip drum trauma, aprotinin at a dose of 20,000 KIU/kg prolonged survival time to 2.1 +/- 0.3 hr (p less than 0.05) and 40,000 KIU/kg prolonged the survival time of rats to a greater extent (3.1 +/- 0.4 hr, p less than 0.001) compared to rats given only its vehicle (1.1 +/- 0.2 hr, mean +/- SE). The improved survival was accompanied by inhibition of the plasma accumulation of the cardiotoxic peptide, myocardial depressant factor (MDF). However, aprotinin showed no inhibitory effect on the plasma accumulation of the lysosomal enzyme, cathepsin D. Aprotinin has a beneficial effect on traumatic shock in rats possibly by its potent inhibitory action on MDF formation.

Animals↗
PubMed1978

Effect of sera from cystic fibrosis homozygotes and heterozygotes on glucose metabolism in Vero cells.

The effect on intracellular production of carbon dioxide from glucose of sera from cystic fibrosis (C.F.) homozygotes and heterozygotes was determined in an established cell line (Vero cell) by a double-blind assay. CO2 production was reduced when cells were incubated with an ammonium-sulphate-precipitated fraction of sera from C.F. homozygotes and heterozygotes but not by a similar fraction from sera of healthy donors.

Animals↗
PubMed1978

[Behavioral and EEG effects of triazolam in comparison with those of diazepam (author's transl)].

Triazolam was 4 to 5 times as potent as diazepam in reducing hyperemotionality of either septal-lesioned or olfactory bulbectomized rats (O.B. rats), and in suppressing muricide in O.B. rats. This agent was equipotent with diazepam in inhibiting fighting behavior of long-term isolated mice, but was longer in duration of action. Triazolam was approximately 4 times more potent than diazepam in preventing pentetrazol convulsion, but was 10 times less potent in inhibiting maximal electroshock convulsion in mice. The muscle relaxant effect of triazolam as assessed by the inclined screen test was 34 times, and the effect on rotarod performance was 17 times more potent than that of diazepam in mice. Triazolam (0.2 approximately 0.5 mg/kg i.v.) changed the EEG to a drowsy pattern in unanesthetized rabbits with a chronic electrode implant, and suppressed the EEG arousal response to auditory stimulation and electrical stimulation given to either the mesencephalic reticular formation or posterior hypothalamus. The limbic afterdischarges induced by either hippocampal or amygdaloid stimulation were also markedly inhibited by triazolam. These EEG effects of triazolam were qualitatively similar to, but were 4 to 5 times more potent than those of diazepam. These results indicate that triazolam is a potent tranquilizer with a longer duration of action, and the muscle relaxant effect is considerable as compared with diazepam.

Aggression↗
PubMed1978

Enzymatic decarboxylation of L-threo-3,4-dihydroxyphenylserine in rat heart.

Decarboxylation of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) by the higher speed supernatant of the rat heart homogenate and the regional distribution of L-threo-DOPS decarboxylase activity were examined. Decarboxylation was demonstrated to occur specifically with L-isomer but not with D-isomer. Addition of pyrogallol was necessary for maximal recovery of norepinephrine. The optimal condition for decarboxylation of L-threo-DOPS by the rat heart enzyme was similar to conditions required with the enzymes from brain and kidney. Under the optimal conditions, Km and Vmax for L-threo-DOPS were 2.1 mM and 6.4 nmoles/mg protein/15 min, respectively. Decarboxylation of L-threo-DOPS was markedly inhibited by D-threo-DOPS and D-DOPA. The L-aromatic amino acid decarboxylase activity was highest in the right auricle followed by the atrial body, the left auricle, the right ventricle and the left ventricle.

Animals↗
PubMed1978

Absorption of 5-fluorouracil through gastric epithelium.

We examined the amount of 5-Fu absorbed through the gastric epithelium after oral administration in both dogs and patients with bladder tumors. The concentrations of 5-Fu in the serum, bladder wall, tumor mass and regional lymphnodes were sufficiently high to suppress the growth of tumor cells.

Absorption↗
PubMed1978

Effects of dobutamine on coronary circulation and cardiac metabolism of the dog.

Effects of (+/-)-4-[2-(3-p-hydroxyphenyl-1-methyl-amino)ethyl]pyrocatechol (dobutamine) on coronary circulation and cardiac metabolism were investigated using the heart in vivo and the isolated perfused heart of dogs. In the heart in vivo dobutamine 1--30 microgram/kg i.v. and 1--100 microgram i.c. produced dose-dependent increases in coronary perfusion pressure, coronary blood flow, heart rate and left intraventricular pressure. In the perfused heart dobutamine 10 microgram i.c. increased coronary flow, heart rate, cardiac contractility and myocardial oxygen consumption. Delta redox potentials decreased but did not show negative values. Propranolol 0.1 mg/kg i.v. and 0.1 mg i.c. inhibited these effects of dobutamine. Dobutamine shows basically the same actions as isoproterenol, but does not reduce the coronary perfusion pressure by the relatively high dose applied. The results suggest that dobutamine may have a selective adrenergic beta 1 receptor stimulating action on the heart and have a merit in maintaining the coronary perfusion pressure.

Animals↗
PubMed1978

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole dihydrochloride (DEPO) on cardiac functions and myocardial metabolism of the dog.

Effects of 5-([2-(diethylamino)-ethyl]amino)-3-phenyl-1,2,4-oxadiazole (DEPO) on cardiac functions and myocardial metabolism were examined using the heart in vivo and the isolated perfused heart of dogs. In the heart in vivo DEPO i.v. produced dose-dependent decreases in coronary perfusion pressure (PP), heart rate (HR), left ventricular pressure (LVP), dP/dt max of LVP and coronary vascular resistance (VR). DEPO i.c. dose-dependently increased left circumflex coronary flow (LCCF) and decreased PP, LVP and dP/dt max of LVP, but did not change HR. In the isolated perfused heart, DEPO induced a marked increase in coronary blood flow (CBF) and depressed HR and myocardial contractile force. Myocardial oxygen consumption and myocardial redox potential were not significantly changed. DEPO could not modify the effects of isoproterenol, adenosine and reactive hyperaemia on the heart. The results suggest that DEPO may have a coronary vasodilating action and some direct inhibitory actions on the heart.

Adenosine↗
PubMed1978

Comparison of lactate pyruvate and potassium concentration in the cardiac lymph and, arterial and coronary sinus plasma in dogs.

Lactate (LA), pyruvate (PYR) and potassium (K) concentration in the cardiac lymph were compared with those in the arterial and coronary sinus plasma in dogs. In each substance, there was a good correlation between the plasma and cardiac lymph level in the control period. In respect to LA and PYR, the concentration in the cardiac lymph correlated more with that in the arterial plasma than in the coronary sinus one. During the infusion of isoproterenol, LA and PYR in the plasma increased, while K decreased. Each substance in the cardiac lymph changed to the same degree as in the plasma in mean values. Good correlation was also observed between the arterial plasma and cardiac lymph level during the administration of the agent. However, there was no correlation of PYR between the coronary sinus plasma and the cardiac lymph. During the administration of dipyridamole LA in the coronary sinus plasma increased and that in the arterial plasma decreased. LA in the cardiac lymph did decrease as in the arterial plasma. It is concluded that the concentrations of LA, PYR and K in the cardiac lymph can be changed depending upon changes in those in the plasma and the former two parameters seem to change depending upon those in the arterial plasma rather than the coronary sinus one.

Animals↗
PubMed1977

Effects of increased cardiac mechanical performances on flow rates of cardiac lymph in dogs.

Relationship between flow rates of cardiac lymph (LF), and coronary blood flow (CF), coronary perfusion pressure (PP), left ventricular peak systolic pressure (LVSP) and heart rate (HR) was studied in open-chest dogs. Intra-coronary administration of catecholamines (CA) and electrical stimulation of the cardiac sympathetic nerve (ES) increased LF transiently with a concomitant rise in the cardiac mechanical performance, while dipyridamole induced no change in LF in spite of a marked increase in CF. Isoproterenol at does of 0.3 and 3x10(8) g/kg induced an increasein LF to 119 +/- 4 and 167 +/- 20% (mean +/- SE); norepinephrine, 0.3 and 3 X 10(7) g/kg, to 118 +/- r and 141 +/- 13%; ES AT 5 and 20 Hz, to 135 +/- 11 and 167 +/- 10%, respectively. Peak responses of LF correlated with changes in LVSP (R = 0.59, N l1,P less than 0.001), CF Tr = 0.53, n = 51, P less than 0.001), PP (r = 0.49, n = 51, P less than 0.001) but not with changes in HR (r = 0.27, n = 51, 0.05 less than P less than 0.10). Cardiac pacing also showed a poor correlation between the changes in LF and HR under the same LVSP within the changes in HR up to 134% of control value (r = -0.12, n = 17, P GREATER THAN 0.50). It is concluded that LF is independent of changes in HR, and increased LF after CA or ES may be caused mainly by an augmented propulsive force.

Animals↗