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Biomedical subjects

M Sakamoto

Publications and source records attributed to M Sakamoto.

At least 865 records · Page 48Linked to original sources
PubMed1978

Human rotavirus infection in infants and young children with intussusception.

Human rotavirus was detected by electron microscopy in 11 of 30 infants and young children with intussusception (37% of subjects under study). Serologic complement fixation tests revealed evidence of infection with the rotavirus in 70% of the patients examined who eliminated the rotavirus in their stools. These results indicate that human rotavirus, in addition to adenovirus, may be an infectious agent causing intussusception in infants and young children.

Adenoviruses, Human↗
PubMed1978

A long-term survey of rotavirus infection in Japanese children with acute gastroenteritis.

Human rotavirus was detected by electron microscopic examination of the stools of 320 (63%) of 506 infants and young children hospitalized with acute gastroenteritis between December 1974 and March 1977. Serologic responses to infection with the rotavirus were revealed by the complement-fixation test in 130 (70%) of 185 patients examined. During the study period three epidemics of human rotavirus infection occurred during the winter months. The peak incidences occurred in January 1975 (88% of patients positive by serologic analysis or electron microscopy of stools), January 1976 (92%), and February 1977 (96%). Rotavirus was detected in the stools of 288 (79%) of 365 patients tested during the cooler months (December to March) and 35 (25%) of 141 during the rest of the year. In the summer (June to August), rotavirus infection occurred rarely. The frequency of human rotavirus infection was highest among patients aged six to 11 months. These results indicate that human rotavirus can be regarded as a major etiologic agent of acute gastroenteritis in infants and young children, of which wintertime epidemics are common in Japan.

Acute Disease↗
PubMed1978

The chemoattractant properties of comedonal components.

Acculation of clusters of polymorphonuclear leukocytes (PMN) along the periphery of the walls of comedones (predominantly of the closed variety), has been described as the first change marking the transition of quiescent, noninflamed lesions in acne, into inflammatory ones. The present study analyzed the chemoattractant properties of different comedonal components for human PMN in an effort to evaluate the potential significance of these substances in stimulating the chemotactic response of PMN in the initial phases of inflammatory acne. It was found that the lipids extracted from pooled comedones had chemotactic activity for PMN in vitro. Beyond that, all chemotactic activity in comedones was related to bacteria. Propionibacterium acnes produced low molecular weight, dialyzable, heat stable chemotactic factors which were released into culture medium during bacterial growth. In addition to the extracellular cytotaxins, P. acnes whole cells and other extracellular products were strong cytotaxigens and activated heat labile chemotactic factors in human and guinea pig serum.

Acne Vulgaris↗
PubMed1978

An observation of thromboxane A2 in arterial blood after cholesterol feeding in rabbits.

Agents responsible for the entry of cholesterol-bearing lipoproteins into the arterial wall represent local risk factors in atherogenesis. In an attempt to identify these agents, we inserted a catheter into the ascending aorta of rabbits and 5 ml of arterial blood sample was withdrawn. The contraction of the aortic strip of rabbit against Piper and Vane's antagonists with application of this sample was observed. Samples obtained after feeding of 1 Gm/Kg of cholesterol and after an intravenous administration of thromboxan A2 (TXA2) contracted the aortic strip. Samples from non-treated rabbits or those obtained after intravenous administration of 10 microgram of epinephrine or norepinephrine did not contract the strip. Previous administration of 20 mg/Kg of indomethacin decreased the contraction developed after feeding of 1 Gm/Kg of cholesterol. It was suggested that TXA2 might be released into the arterial blood by the ingestion of cholesterol and might be one of the agents repsonsible for the entry of lipoproteins.

Animals↗
PubMed1977

Gas-liquid chromatography and mass spectrometry of lanthionine, lysinoalanine, and S-carboxyethylcysteine.

A programmed-temperature gas-liquid chromatographic method of analysis of amino acids as their n-butyl esters of N(O)-trifluoroacetyl derivatives with a dual column system using OV-17 and Dexsil 300 GC as stationary phase is discussed. The method is particularly suitable for analysis of chemically modified amino acids in the hydrolyzates of chemically modified wool and other protein fibers. Combined gas-liquid chromatography-mass spectrometry is used to identify unequivocally the molecular structure of modified amino acids. Lanthionine, lysinoalanine, and S-(2-carboxyethyl)-cysteine in the hydrolyzates of chemically modified wool fibers can be quantitatively analyzed by the gas-liquid chromatographic method of Dexsil 300 GC. N(epsilon)-(2-Carboxyethyl) lysine was detected by the combined gas-liquid chromatography-mass spectrometry in the hydrolyzate of reduced wool treated with acrylonitrile.

Alanine↗
PubMed1977

A reevaluation of fatty acids as inflammatory agents in acne.

The currently widely held theory that intrafollicular free fatty acids (FA) are the primary agents instigating inflammatory changes in acne is based on circumstantial evidence. There is no direct evidence that FA in physiologic concentrations are inflammatory. In the present study the quantities of FA present in isolated pilosebaceous ducts and in isolated comedones were analyzed. Using these values, the effect of FA on intracutaneous injection into human skin was investigated. The range of FA in 257 isolated pilosebaceous ducts from skin of the upper back of 10 male subjects was 0.19 to 2.43 mug, with an average of 0.89 +/- 0.75 mug of FA per duct. The mean FA content in 45 open comedones was 63.6 +/- 24.8 mug per comedone. Fatty acids for intracutaneous testing were isolated from human skin surface lipids and from hydrolyzed triglycerides purified from pooled isolated sebaceous glands. Twenty-six subjects received 100 mug of FA intracutaneously in the upper back. The response to FA injections could not be distinguished from the response to saline control injections. By 24 hr no erythema, induration, or any visible marks of inflammation were present in the skin of any of the subjects tested. At the histologic level a mild inflammatory infiltrate consisting perdominantly of lymphocytes was slightly more marked in the FA injection site than in the saline control injection site. Increasing the amount of FA injected to 500 mug still produced no visible inflammatory response in human skin. We conclude that intracutaneous injections of FA in physiologic concentrations do not produce more than a very mild inflammatory reaction in human skin and suggest that the role of Propionibacterium acnes in the pathogeneisis of acne may be more complex than merely as a source of intrafollicular lipases.

Acne Vulgaris↗