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Biomedical subjects

H Takeda

Publications and source records attributed to H Takeda.

At least 703 records · Page 39Linked to original sources
PubMed1976

Correlation between myocardial and plasma concentration of digitoxin and its metabolites with special reference to digitoxin radio-immunoassay.

According to our prevous study, the metabolites of digitoxin show nearly dentical affinity with digitoxin antibody. The present study reveals relatively constant ratio of heart to plasma in total 3H-counts, and the concentration of metabolites are ver similar between the two throughout the time investigated which indicates digitoxin concentration of plasma as determined by radioimmunoassay reflects well that of myocardium, although it may contain metabolites.

Animals↗
PubMed1976

The experiment on the protein exposed to acoustic wave in model of hair cells.

Why do animals have intense troubles mainly in the basal turns of their cochleae by exposure to sound and the ototoxity? I thought that the protein in cells had an important relation to this subject. So I performed this experiment. I made model of hair cells of silicon and poured three kinds of solutions of protein into them. And I checked the ionization of the protein and its denaturation by giving strong energy of oscillation to them like the same idea of photoelectric effect. As the result, as for the protein liquid, I noticed the increase of volts just after it was exposed to sound and about 3 hours later, I observed the figure decreased gradually. From this phenomenon, I presumed that the protein in sensory cells became a factor of the stimulation by receiving strong energy conversely. Low-percent protein liquid had less effect caused by sound.

Acoustic Stimulation↗
PubMed1976

Effect of insulin on mitochondrial oxidative phosphorylation and energy charge of the perfused guinea pig liver.

The effect of insulin was investigated in the isolated guinea pig liver perfused with Krebs-Ringer bicarbonate buffer containing red blood cells and albumin. In the mitochondria isolated from livers perfused with 10 units of insulin per hour, the phosphorylative activity with glutamate as a substrate increased to about 160 per cent of control 60 minutes after the beginning of perfusion (p less than 0.01). Such an enhanced phosphorylative activity was accompanied by increases in the respiratory control ratio, state 3 respiration, and P/O ratio. On the other hand, in the liver perfused with insulin, the levels of the energy charge and adenine nucleotide quotient increased to a significant degree as compared to the liver without insulin (p less than 0.01 and p less than 0.05, respectively). It is suggested that insulin plays an important role as a portal factor in regulating mitochondrial oxidative phosphorylation and the levels of the phosphorylated adenine nucleotides.

Adenosine Diphosphate↗
PubMed1975

Purification and properties of a lipid acyl-hydrolase from potato tubers.

1. A pure lipid acyl-hydrolase was prepared from potato tubers by acetone precipitation, Sephadex G-100 and DEAE-Sephadex A-50 column chromatography, and by electrofocusing. 2. The purified enzyme was an acidic protein of pI 5.0 and molecular weight of about 70 000. Km values were 0.38 mM for monogalactosyldiacylglycerol and 1.7 mM for phosphatidylcholine. 3. The hydrolytic activity of the enzyme on different substrates was determined. The relative rates were acylsterylglucoside greater than monogalactosyldiacylglycerol greater than monogalactosylmonoacylglycerol greater than digalactosyldiacylglycerol greater than diagalactosylmonoacylglycerol, while the rates for phospholipids were lysophosphatidylcholine greater than phosphatidylcholine greater than lysophosphatidylethanolamine greater than phosphatidylethanolamine. 4. Analyses of enzymatic hydrolysis products suggested that a single enzyme had both galactolipase and phospholipase activities, and for the phospholipids it showed activities similar to phospholipase B and glycerylphosphorylcholine diesterase. 5. A competitive relation was found between monogalactosyldiacylglycerol and phosphatidylcholine as substrates of the enzyme, indicating that the active sites for both substrates may be the same. 6. It was suggested that histidine and probably serine residues were important to the enzymic activity, and that a tyrosine residue might be involved in the activity as an accessory component.

Binding Sites↗
PubMed1975

Antiarrhythmic effect of aprindine on several types of ventricular arrhythmias.

The antiarrhythmic effect of aprindine was compared with those of lidocaine and propranolol on several ventricular arrhythmias-epinephrine arrhythmias in cats, ouabain arrhythmias in cats and guinea pigs, ischemic ventricular arrhythmias in coronary-ligated Beagle dogs. Antiarrhythmic effects of aprindine and lidocaine were observed both in ouagain and ischemic arrhythmias, but not in epinephrine arrhythmias. While propranolol had a strong antiarrhythmic effect against epinephrine and ouabain arrhythmias, it did not increase sinus beats in ischemic arrhythmias. Marked anti-arrhythmic effects of aprindine in ischemic arrhythmias were observed in dogs using either single intravenous administration (4 mg/kg) or intravenous infusion (200 mug/kg/min, 2 mg/kg). Antiarrhythmic activity of aprindine is considered to be about twice as strong as that of lidocaine, but lidocaine is less toxic in experimental animals.

Ajmaline↗
PubMed1975

Junction potentials in response to ortho- and anti-dromic stimulation of hypogastric nerve in mouse vas deferens.

The interaction of the junction potentials in response to ortho- and antidromic hypogastric nerve stimulation in mouse vas deferens was studied, using an extracellular recording method. Ortho-dromic repetitive hypogastric nerve stimulation (10 Hz, 5 min) simultaneously depressed the amplitude of the junction potentials in response to both ortho- and anti-dromic hypogastric nerve stimulation (post-te-tanic depression). No time-lag in recovery from the post-tetanic depression was observed between the junction potentials recorded from two separate electrodes, indicating that the proximodistal axonal flow of available transmitter was not involved in the recovery process. Double shocks, with intervals from 10 msec to 1 sec, were applied to the hypogastric nerve. The junction potentials in response to ortho- and ortho-dromic or anti- and anti-dromic double shock were markedly facilitated. On the contrary, the junction potentials in response to ortho- and anti-dromic double shocks were not facilited. The findings indicate that facilitation of the junction potentials is produced by the impulses propagated in the same direction along the terminal axon and also that the origin of the facilitation may be at a pre-junctional site.

Animals↗