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Biomedical subjects

K Takeuchi

Publications and source records attributed to K Takeuchi.

At least 1,333 records · Page 74Linked to original sources
PubMed1980

Comparison of kinetic properties of the ATPase reaction of arterial smooth muscle myosin with skeletal muscle myosin.

Myosin was prepared from arterial smooth muscle, and a hybrid actomyosin was formed from arterial myosin and rabbit skeletal muscle F-actin. We performed kinetics on the ATPase reaction [EC 3.6.1.3] of arterial myosin and the hybrid actomyosin at high ionic strength, and compared the kinetic properties of arterial myosin ATPase with those of skeletal muscle myosin ATPase. No significant difference was found between these two myosins in the size of the initial Pi burst, the amount of bound nucleotides, and the rates of various elementary steps in the ATPase reaction. On the other hand, two important differences were observed between the hybrid actomyosin and skeletal muscle actomyosin: (i) The amounts of ATP necessary for complete dissociation of the hybrid and skeletal muscle actomyosins were 2 and 1 mol/mol of myosin, respectively. (ii) The rate of dissociation of the hybrid actomyosin induced by ATP was much lower than that of skeletal muscle actomyosin and also was lower than that of fluorescence enhancement.

Actins↗
PubMed1980

Mucosal gastrin receptor. III. Regulation by gastrin.

Specific binding of 125I-labeled gastrin to rat gastric mucosal membranes was found to vary with serum gastrin levels. The dissociation equilibrium constants were not significantly different between receptor preparations. However, the binding capacities of the membrane preparations were directly correlated with serum gastrin levels. Fasting, feeding a liquid diet, and antrectomy significantly decreased serum gastrin and the concentrations of the gastrin receptor. Treatment of fasted and liquid-fed animals with pentagastrin prevented the decrease in receptors. Vagotomy increased both binding capacity and serum gastrin levels. These data indicate that gastrin stimulates the production of its own receptor. The upregulation of the gastrin receptor was evident if the binding capacity was expressed per milligram of protein, per microgram of DNA, or per amount of 125I-labeled choleragen bound to the same membrane preparation. This indicates that the biological response to gastrin is controlled in part by the regulation of the number of gastrin receptors present and that gastrin plays a role in this regulatory process.

Animals↗
PubMed1980

Mucosal gastrin receptor. IV. Binding specificity.

We used membrane preparations of rat oxyntic gland mucosa to test the binding of various gastrin analogues to the gastrin receptor. Using [125I]15-Leu G-17 as a marker, a concentration of 4 X 10(-9) M unlabeled G-17 inhibited binding 50%. The tetra-, penta-, and hexapeptides of gastrin caused similar 50% inhibitions of binding at concentrations of 1 X 10(-7) M, 3 X 10(-8) M, and 7 X 10(-9) M, respectively. The heptapeptide caused only slightly less inhibition than G-17, whereas the decapeptide was equivalent in potency. Neither the G-17 nor G-34 that had the active tetrapeptide removed caused 50% inhibition of binding. When compared to G-17, these analogues produced only a 25% inhibition of binding at concentrations of 10(-8) M. We also failed to inhibit binding more than 25% when we used an analogue that had the amide removed from the C-terminal phenylalanine. Atropine, metiamide, and mepyramine did not alter the binding of gastrin to receptor. The results of binding specificity approximate the changes in biological potency associated with these compounds. This study adds further support that the gastrin receptor in question is responsible for the physiological effects of the hormone.

Animals↗
PubMed1980

[Inhibitory action of non-steroidal anti-flammatory drugs on prostaglandin synthesis and release (author's transl)].

Inhibitory action of non-steroidal anti-inflammatory drugs (NSAID)on the synthesis and release of prostaglandin (PG) was studied both in vivo and in vitro. In the experiment with PG synthetase from beef seminal vesicle, the potency of NSAID on the inhibitory action of PGE synthesis was: flurbiprofen greater than 4-(p-chlorophenyl)-2-phenyl-5-thiazoleacetic acid (CH-800) greater than indomethacin greater than diclofenac-NA greater than aspirin. Inflamed synovial tissue, as induced 6 hours after carrageenin injection into the knee joint cavity of rats was used to examine the inhibitory action of NSAID on PGE release from the tissue. Both in vivo and in vitro, CH-800 was the most potent and flurbiprofen and indomethacin were next potent of the five drugs. Effects of NSAID on the excretion of PGE and PG main urinary metabolite (PGMUM) in rat urine were determined. The excretion of urinary PGE was significantly decreased by administration of NSAID. Flurbiprofen and CH-800 had the most potent inhibitory action on the excretion of PGEMUM, but the urinary excretion of PGFMUM was not significantly inhibited by NSAID. Thus, the inhibitory effects of NSAID associated with PG synthesis were generally in proportion to the effect of the drugs with PG synthetase, however, there were differences regarding PG synthesis in inflamed tissue and the urinary excretion of PG metabolites.

Acetates↗
PubMed1980

[Three cases of traumatic intracerebral hematoma with ventricular hemorrhage (author's transl)].

Three heavy drinkers, the patients fell down stairs while inebriated and were hit on their heads. Utilizing CT, we found that the hematomas in all three cases were accompanied by ventricular hemorrhage which, in two of the cases, were similar to hypertensive intracerebral hematoma in the basal ganglia. None of the three had a history of hypertension. We are of the opinion that the vulnerability of cerebral arteries, especially in the basal ganglia, of such heavy drinkers added to the traumatic force and led to the pathogenic bleeding. We were unable to find a correlation between the intracerebral hematoma and the site of the hit. It is assumed that immediate removal of the hematoma in cases of intracerebral hematoma with ventricular bleeding can result in the survival of the patient.

Adult↗
PubMed1980

[Evaluation of laser surgery against brain tumor (author's transl)].

UNLABELLED: A surgical carbon dioxide laser unit (Laser) has been used in 26 cases of various brain tumors, including 10 meningioma (4 sphenoid ridge, 3 parasagittal, 1 falx, 1 olfactory, 1 posterior fossa); 12 glioma (7 glioblastoma, 5 astrocytoma); two metastatic brain tumors; 1 hemangioblastoma, and 1 AVM. Criteria for Laser use based on evaluation and location of meningioma were: grade 1, convenient but adjuvant; grade 2, also necessary; grade 3, indispensable. Most meningioma in convexity and parasagittal were grade 1-2, with those in the sphenoid ridge grade 2-3. In the glioma group, hemorrhage in 3 cases of glioblastoma was easily Laser-controlled, and the tumors wasted away in a short time with vaporization. There was minimal mechanical effect on the adjacent tissue. CONCLUSION: In neurosurgery, Laser is obligatory in sphenoid ridge meningioma to dissect the internal carotid artery, middle cerebral artery, cavernous sinus, sphenoid ridge, etc. It is very useful in glioma, especially glioblastoma, considering shortened surgical duration, decreased blood loss and extended tumor resection. Laser surgery is proposed as most appropriate for brain tumors in elderly and poor risk cases mainly for its vaporizing function.

Adult↗
PubMed1980

[Biological assay of prostaglandin in rat urine using fundus of rat stomach (author's transl)].

Male Wistar rats, weighing about 180 g, were used. Strips from the fundus of the stomach were prepared from animals deprived of food for 24 hours and fed for 10 minutes before the decapitation. The strips were suspended in 2 ml of organ bath containing Tyrode solution kept at 30 degrees C, and the isometric contraction was determined. Prostaglandins in rat urine were separated by column chromatography and determined by biological assay. No less than 50 pg of PGE2 and 250 pg of PGF2 alpha with good precision could be determined quantitatively using this particular bioassay. Excretion of urinary PGE in the healthy male rat was 29+8+/-1.79 ng/day and PGF was 1.9+/-0.27 ng/day.

Animals↗