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Biomedical subjects

A Takeuchi

Publications and source records attributed to A Takeuchi.

At least 469 records · Page 26Linked to original sources
PubMed1981

Cellular cooperation in polymorphonuclear leukocyte chemotaxis: augmentation by neutrophil cytoplasm.

The number of polymorphonuclear leukocytes (PMN) responding to a chemotactic stimulus is influenced by the cell density. Evidence is presented that the cytoplasmic fraction of PMN augments the response of neutrophils to endotoxin-activated serum but the activator of chemotaxis (CACh) in cytosol is not chemotactic itself. This cytoplasmic neutrophil cytosol is not present in nuclear, microsomal or large granular fractions. Preliminary characterization studies suggest that CACh is nondialyzable, has a molecular weight of less than that of albumin, is heat stable (56 degrees C for 30 min) but is destroyed by trypsin. Studies on intracellular concentrations of cAMP and cGMP following incubation of PMN with various subcellular fractions suggest that CACh causes the loss of intracellular cAMP, a finding which could account for its chemokinetic action. As expected, the lysosomal fraction of PMN was chemotactic and reduced the net negative surface charge of neutrophils. CACh, however, was neither chemotactic nor did it alter the charge density on PMN surfaces. These studies provide evidence for cellular cooperation in the initial phases of the chemotactic response. The clustering of PMN along endothelial surfaces could provide the necessary local cell density for this augmented response to take place.

Albumins↗
PubMed1981

Exercise stress body surface isopotential map in patients with coronary artery disease: comparison with coronary angiographic and stress myocardial perfusion scintigraphic findings.

to locate the ischemic area in 22 patients with angina pectoris, exercise stress body surface isopotential maps (MAPs) were assessed and compared with coronary angiography and myocardial stress scintigraphy. Taking coronary angiographic findings into consideration, 4 types of ischemic MAP responses, i.e., septum and anterior, lateral, inferior, and posterior wall ischemia were postulated. Sensitivity of stress MAP was 71% for the average and more than stress imaging. Specificity of stress MAP was 46% for the average and less than stress imaging.

Angina Pectoris↗
PubMed1981

[Idiopathic neurologic diseases in dogs and cats in Japan from the viewpoint of animal models of human disease (author's transl)].

This study was intended to demonstrate the neurological characteristics of idiopathic neurologic diseases of dogs and cats as a material for evaluating them as animal models for human diseases. A hundred and nineteen animals selected for this study from among outpatients with various neurological disorders presented to the Veterinary Hospital of University of Tokyo were studied mainly by the neurological examination with assistant methods of electroencephalography and electromyography. Hydrocephalus and vestibular diseases were highest in incidence in dogs, followed in order by encephalitis and epilepsy. Choleiform movements or other abnormal movements such as athetosis and hemiballism that are seen in diseases of the extrapyramidal system of man were not observed in dogs. Cerebellar degenerative disease showed the highest incidence in cats, which is believed to occur by transplacental infection of panleukopenia virus. Intervertebral disk disorders, the most common neurologic disease in the dog, usually occurred in the thoracic, unlike in man, and lumbar segments, not only causing pain but precipitating paresis or paralysis of the legs or of the trunk.

Animals↗
PubMed1981

Simplified assay of vitamin D2 in fortified dried milk by using two steps of high-performance liquid chromatography.

A simplified method for the determination of vitamin D2 in fortified dried milk was established by using two steps of high-performance liquid chromatography (HPLC). About 1 g of fortified dried milk was accurately weighed and directly saponified. The extracted unsaponifiable matter was first subjected to preparative HPLC using a Nucleosil 5C18 column (reversed-phase type) with acetonitrile-methanol (1:1) as a mobile phase and a fraction containing vitamin D2 was separated. The separated fraction was subsequently subjected to analytical HPLC using a Zorbax SIL column (straight-phase type) with 0.4% isopropanol in n-hexane as a mobile phase. Since the peak corresponding to vitamin D2 was clearly observed with separation from other concomitants on the chromatogram of the analytical HPLC, the vitamin was assayed by estimating the peak height. The overall recovery of vitamin D2 by the proposed method was 94.3 +/- 2.3% (mean +/- SD). Naturally occurring vitamin D3 derived from cow's milk was negligible in commercial fortified dried milk sold in Japan. When the proposed method was applied to 5 kinds of commercial fortified dried milk, satisfactory results were obtained.

Animals↗
PubMed1981

[Two-dimensional echocardiography in preoperative evaluation of mitral stenosis (author's transl)].

Two-dimensional echocardiograms were correlated with the operative findings and surgical procedures in 46 patients with mitral stenosis. In addition, a new projection evaluating subvalvular lesion more precisely was reported. Two-dimensional echocardiographic findings studied were 1) pathology of the two leaflets of the mitral valve, 2) valve area, and 3) subvalvular lesion. The findings of leaflets and valve area were well correlated with the operative findings. But there were six cases with discrepancies in the initial 22 cases about the findings of subvalvular lesion; there were 5 false negative and one false positive case. It was considered that insufficient information about the appositional zone of the mitral valve and chordae tendineae made it difficult to evaluate them correctly. We have designed a new projection for delineating the subvalvular apparatus and employed in the next 24 cases, and the transducer was placed near the apical heart to visualize 4 chambers. This eliminated greatly the false positive cases (only 2 out of 24 cases). There were three cases of mitral valve replacement (MVR) in the initial 22 cases, but we could expect the necessity of MVR in only one case, and we had to perform chordotomy, papillotomy, or debridement as well as commissurotomy in two false positive cases. In the next 24 cases, however, we could predict it in all three cases of MVR before the operation. It was valuable for surgery of mitral stenosis to get enough information about the subvalvular lesion as well as mitral leaflets by two-dimensional echocardiography.

Adult↗
PubMed1980

Alteration of polymorphonuclear leukocyte surface charge by endogenous and exogenous chemotactic factors.

We investigated the effects of chemotaxins on the surface charge of isolated human PMN. Chemotaxis was ascertained using Boyden chambers. Surface charge was calculated using data derived from cell mobility as measured in a cytophorometer. The electrophoretic mobility of cells exposed to all chemotactic agents studied was altered. Endotoxin-activated serum containing C5a, PMN lysosomal extracts from "resting" and from crystal-stimulated cells, and Gly-His-Gly, a synthetic tripeptide, all significantly reduced the net negative surface charge of isolated neutrophils. Only chemotactically active substances effected this change; controls including heat-inactivated serum, other subcellular fractions, and an inert tripeptide, Gly-Gly-Gly, did not alter cell mobility in an electric field. These findings are consistent with studies by others on the effects of chemotactic factors on cation fluxes and cell aggregation and suggest a possible mechanism by which PMN directional migration is regulated.

Chemotactic Factors↗
PubMed1980

Distribution and pharmacological properties of synaptic and extrasynaptic glutamate receptors on crayfish muscle.

1. The distribution of glutamate sensitivity was measured in the opener muscle in the walking legs of the crayfish (Cambarus clarkii). L-Glutamate was ionophoretically applied under visual control. 2. Bundles of a few muscle fibres were isolated and viewed with Nomarski optics. Two axons, presumably excitatory and inhibitory, branched widely over the surface of individual muscle fibres, forming numerous clusters of boutons or varicosities. 3. Glutamate sensitivity was measured from the slope of the dose-response curves obtained by ionophoretic application of L-glutamate and expressed as mV/nC. The highest sensitivities were about 100 mV/nC, obtained at the edge of synaptic boutons. The sensitivity declined to less than 5% about 2 micrometer away from the synaptic terminal. The time course of glutamate potentials was approximately the same as that of spontaneous synaptic potentials. 4. Glutamate depolarization started within 300 microsec after ionophoretic release of glutamate. This time lag was shorter than the synaptic delay of the nerve-evoked synaptic potential measured with an extracellular micro-electrode. This indicates that glutamate depolarization results from a direct action on the post-synaptic receptor. 5. Application of L-alpha-kainic acid decreased the amplitude of the glutamate potential produced at the synaptic region, whereas kainate increased the amplitude of the glutamate potential at the extrasynaptic region. It is suggested that the pharmacological properties of the extrasynaptic receptor differ from those of the synaptic receptor. Possible mechanisms for the different actions of kainate are discussed.

Animals↗