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Biomedical subjects

T Ohe

Publications and source records attributed to T Ohe.

At least 217 records · Page 12Linked to original sources
PubMed1983

The effect of pacing site on the echo zone in patients with concealed Wolff-Parkinson-White syndrome.

In 14 patients with the left-sided concealed Wolff-Parkinson-White syndrome, the effects of changing atrial pacing site on the echo zone were evaluated. In 12 patients, re-entrant tachycardia was induced by premature stimuli both in the coronary sinus (CS) and the high right atrium (HRA). In the remaining 2 patients, the tachycardia was induced by premature stimuli only in the CS. The lower limit of the echo zone was shifted to a longer coupling interval during CS pacing in 12 patients. The longer effective refractory period (ERP) of the CS was responsible for the shifting of the lower limit of the echo zone to a longer coupling interval. The upper limit of the echo zone was shifted to a longer coupling interval during CS pacing in 10 patients. The difference of atrial conduction times from the site of stimulation to the 2 conduction pathways (the normal conduction pathway and the accessory pathway) is thought to be responsible for the shifting of the upper limit of the echo zone.

Adult↗
PubMed1982

Use of milk progesterone enzyme immunoassay for early pregnancy diagnosis in cows.

An enzyme immunoassay using beta-galactosidase as the tracer was applied to determine milk progesterone level in cows. The novel method was reliable and practicable and required only a spectrophotometer and a centrifuge as major equipment. The milk progesterone enzyme immunoassay successfully diagnosed early pregnancy in cows. Milk samples were collected from 268 Holstein-Friesian cows in commercial dairy herds on 20, 21 or 22 days(usually 21 days) after insemination. Progesterone level in skim milk higher than 1.0 ng/ml indi-cated pregnancy. Pregnancy was confirmed by rectal palpation on 60 to 120 days after insemination. The accuracy of the milk progesterone test was 60.0 % (132 220 ) for a positive diagnosis and 100 % (48 48 ) for a negative result. A high incidence of embryonic death, 27.9 % (51 183 ), may have reduced accuracy for a positive test result. The enzyme immunoassay may be an alternative to radioimmunoassay in milk progesterone analysis for pregnancy diagnosis.

Journal Article↗
PubMed1982

Mutagenicity of pyrolysates from guanidine, ureide, secondary amines and polyamines found by the Salmonella/mammalian-microsome test.

Nitrogenous compounds such as guanidine, ureide, secondary amines and polyamines were pyrolysed at 300, 400, 500 and 600 degrees C for 3 min, and the mutagenic activities of the pyrolysates were assayed on Salmonella typhimurium TA98 and TA100 with or without metabolic activation by S9 mix. Among 21 pyrolysates tested, 14, from methylguanidine, agmatine, dihydrouracil, dimethylamine, diethylamine, trimethylamine, triethylamine, pyrrolidine, morpholine, sarcosine, piperazine, piperidine, spermine and spermidine, showed mutagenic activity. In the presence of S9 mix, the mutagenic activity began to appear from the pyrolysate at 400 degrees C, and the pyrolysate at 600 degrees C showed the highest mutagenic activity except that from methylguanidine. The mutagenic activity formed by pyrolysis was more active on TA98 than TA100. In the absence of S9 mix, only 3 pyrolysates - from dimethylamine, diethylamine and pyrrolidine - showed slight mutagenic activity toward TA100. The highest mutagenic activity was observed with the pyrolysate from spermine, followed by those from piperidine, spermidine, piperazine and triethylamine. Some nitrogenous compounds showed slight mutagenic activity after pyrolysis at 300 degrees C for 20 min, although none of the compounds tested showed any mutagenic activity after pyrolysis at 300 degrees C for 3 min.

Amines↗
PubMed1982

The mechanism of A-V conduction delay in A-V nodal gap.

Initial block in the His-Purkinje system was demonstrated in 17 of 71 patients during atrial extrastimulus testing. Of the 17 patients who demonstrated initial block in the His-Purkinje system, ten patients had A-V nodal gap (a type 1 gap). Of these ten patients, progressive increase in A-V nodal conduction was responsible for a resumption of A-V conduction in six patients, dual pathways within the A-V node was responsible in three patients, and the presence of an extra nodal pathway of the A-V node was responsible in one patient.

Atrial Fibrillation↗
PubMed1981

Photoaffinity labeling of a mitochondrial hydrophobic protein by an anisotropic inhibitor of energy transduction in oxidative phosphorylation.

The monoazide derivative of ethidium, the parent compound of which is an anisotropic inhibitor of energy transduction in oxidative phosphorylation, was synthesized and shown to be useful as a photoaffinity probe. Results showed that monoazide ethidium specifically binds to a hydrophobic protein of mitochondria (with an apparent molecular weight of about 6200 in the presence of 0.1% sodium dodecyl sulfate). The molar binding ratios of monoazide ethidium to protein were about 5 and 17 with protein in the nonenergized and energized states, respectively. This protein differed from the dicyclohexylcarbodiimide-binding protein. We refer to this new hydrophobic protein, anisotropic inhibitor-binding protein, in this paper.

Affinity Labels↗
PubMed1981

Purification and properties of urate oxidase from Streptomyces cyanogenus.

Urate oxidase [EC 1.7.3.3] was purified to homogeneity from cell-free extracts of a strain of Streptomyces cyanogenus. The enzyme had a molecular weight of 100,000 and consisted of three subunits each with a molecular weight of 32,000. The isoelectric point was at pH 4.0. No evidence was found for the involvement of copper, iron or coenzymes in the urate oxidase reaction. The enzyme was most active at pH 8 and at 35 degrees C, and was stable between pH 6 and 11 (35 degrees C, 1 h) and below 50 degrees C (pH 7.8, 10 min). The enzyme was inhibited by cyanide and sulfhydryl reagents, but only slightly by heavy metal ions and chelating agents. The activity was inhibited by xanthine and 2-hydroxypurine. The enzyme was found not to be inhibited by high concentrations of uric acid when the activity was assayed in terms of hydrogen peroxide formation. Urea and racemic allantoin were formed from uric acid by the enzyme reaction in phosphate buffer, and urea and other ninhydrin-positive materials in borate buffer.

Amino Acids↗
PubMed1981

A possible mechanism of reciprocating tachycardia initiated by critical shortening of the atrial cycle length in concealed Wolff-Parkinson-White syndrome. Report of a case.

Reciprocating tachycardia in a patient with concealed septal accessory pathway is described. His arrhythmia is characterized by incessant form of tachycardia which is not initiated by a triggering extrasystole but by critical shortening of P-P interval. Electrophysiological studies showed that the occurrence of the reciprocating tachycardia was dependent on atrial pacing rate. By comparing effective refractory period of the atrium, retrograde effective refractory period of the accessory pathway, the conduction time over the reentrant circuit and the difference of conduction time via normal conduction system and via the accessory pathway to the ventricular end of the accessory pathway, it was found that an atrial echo was elicited only at atrial pacing rates at which the difference of conduction times to the ventricular end of the accessory pathway was greater than the effective refractory period of retrograde accessory pathway. These observations suggest that the initiation of the tachycardia in this patient is related to a critical antegrade conduction delay necessary for complete recovery of the ventricular end of the accessory pathway from the preceding antegrade depolarization.

Adolescent↗
PubMed1980

Rhodamine 6G, inhibitor of both H+-ejections from mitochondria energized with ATP and with respiratory substrates.

Rhodamine 6G inhibited ATP hydrolysis by oligomycin-sensitive ATPase, purified from rat liver mitochondria, in good accord with the dose-response curve for its inhibition of energy transduction of ATP synthesis in mitochondria, but it did not inhibit ATP hydrolysis by purified F1. Rhodamine 6G also inhibited both H+-ejections from mitochondria energized with respiratory substrates and with ATP. The present findings show that the inhibitory effect of rhodamine 6G on energy transduction is not due to a modification of the transport system for adenine nucleotides, Pi, and respiratory substrates, and that the inhibition sites of rhodamine 6G are on components related with H+-ejection by redox components and also on F0.

Adenosine Triphosphate↗
PubMed1979

Purification and properties of xanthine dehydrogenase from Streptomyces cyanogenus.

Xanthine dehydrogenase has been purified to a homogeneous state from cell-free extracts of a strain of Streptomyces. The enzyme has a molecular weight of 125,000 and consists of two subunits with a molecular weight of 67,000. The isoelectric point is at pH 4.4. The enzyme exhibits absorption maxima at 273, 355, and 457 nm and contains FAD, iron, and labile sulfide in a molar ratio of 1 : 7 : 1 per subunit. Little molybdenum could be detected. The enzyme is most active at pH 8.7 and at 40 degrees C, and is stable between pH 7 and 12 (at 4 degrees C for 24 h) and below 55 degrees C (at pH 9 for 10 min). The activity is stimulated by K+ at a concentration of 50 mM or more and also by keeping the enzyme at pH 9 to 11. The activity is inhibited by cyanide, Tiron, and p-chloromercuribenzoate and by adenine and urate. Among the compounds tested, hypoxanthine, guanine, xanthine 2-hydroxypurine, and 6,8-dihydroxypurine are oxidized at considerable rates; hypoxanthine is the best substrate. NAD+ is the preferred electron acceptor. Km values of the enzyme for hypoxanthine, guanine, xanthine, and NAD+ are 0.055, 0.015, 0.15, and 0.11 mM, respectively. Marked differences in the properties of this enzyme compared to others are the activity towards guanine, which has a higher affinity for the enzyme than hypoxanthine and xanthine, and a higher reactivity with hypoxanthine than xanthine. The organism has been identified as Streptomyces cyanogenus.

Flavin-Adenine Dinucleotide↗