Search PubMed⌕ Search

Biomedical subjects

M Koyama

Publications and source records attributed to M Koyama.

At least 289 records · Page 16Linked to original sources
PubMed1981

Ultrastructural study of hemangiomas. 2. Benign hemangioendothelioma of the hard palate.

A case of benign hemangioendothelioma which occurred in the hard palate was observed and its electron microscopic findings were described. The endothelial cells contained an abundance of cytoplasmic filaments, but they contained a small number of Weibel-Palade bodies. Two types of endothelial cells, light and dark, were found in our specimen. The former had a cytoplasm with an abundance of ribosomes, rough endoplasmic reticulum and scant filaments. The latter had a cytoplasm with numerous cytoplasmic filaments and a well-developed Golgi apparatus. Tight junctions were seen between the endothelial cells. The majority of the pericytes were accompanied with the vessels in the tumor. Three types of pericytes were recognized: endothelial cell-like, fibroblast-like, and smooth muscle cell-like pericytes.

Adolescent↗
PubMed1980

Determination of manganese in tissues by neutron activation analysis using an antimony pentoxide column.

A rapid and accurate method is presented for the determination of manganese in biological samples, using neutron activation analysis. Biological samples were irradiated at 5000 kW for 30 min. The samples were ashed on a hot plate with 14 mol/l HNO3 and 6 mol/l HClO4, and resolved in 1 mol/l HClO4. 24Na and 24K were removed by passing each sample through in antimony pentoxide column. 54Mn was added as a tracer to calculate the ratio of manganese recovered by the separation procedure. Recovery was over 90%. This method was applied in order to determine manganese in various tissues. In the cervical spinal cord of the controls, the mean manganese concentrations in the anterior horn, the lateral and the posterior columns were 1.14, 1.06 and 0.90 ng/mg of dried tissue, respectively. In two cases if amyotrophic lateral sclerosis the manganese concentrations in the cervical spinal cord were elevated, particularly in the anterior horn and the lateral column.

Amyotrophic Lateral Sclerosis↗
PubMed1980

Simultaneous determination of bestatin and p-hydroxybestatin, a major metabolite, in human serum by gas chromatography mass spectrometry. Utilization of quantitative selected ion monitoring and deuterium labelled internal standard.

A specific and sensitive method for the simultaneous determination of bestatin and its major metabolite, p-hydroxybestatin in human serum has been developed by selected ion monitoring using the corresponding deuterated internal standards. The N-trifluoroacetamide-O-trimethylsilyl either derivatives of the trideuteromethyl esters of bestatin and p-hydroxybestatin were suitable for quantitation by selected ion monitoring. The determination limit of these compounds by the present method is 1 ng ml-1 in human serum.

Adult↗
PubMed1980

The isopotential mapping of the T wave in myocardial infarction.

The isopotential mapping of the T wave in myocardial infarction was studied to find the characteristic abnormality. The negative area on the mapping at the deepest point of the negative T wave was located on the left precordial region or on the left precordial and lateral regions in cases with anterior or anterolateral infarction. In some cases with anterolateral or inferior infarction and in cases with high posterior infarction, an extensive negative area was found on the left back region. In cases with inferior infarction, the negative area was situated on the lower area of the precordial region and/or back region. The ischemic area (the area of the abnormal repolarization) was determined by studying the relation of the zero line of the maps in normal subjects and cases with myocardial infarction. Finally, a comparison between the direction of the maximum T vector and the location of the ischemic area was made.

Electrocardiography↗