Biomedical subjects
Publications and source records attributed to M Masuda.
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We studied biochemically the changes associated with aging and disease in the collagen of articular cartilages and menisci. Pepsin soluble and insoluble collagen were obtained by the method of Miller (1971) from the articular cartilages of seven healthy young and adult, six healthy aged subjects, and of six osteoarthritic and six rheumatoid arthritic patients. One portion of pathological cartilage was histologically examined to eliminate any possible contamination of the fibrous tissue and subchondral bone, and to classify the pathological findings. By the method of Miller, the pepsin soluble and insoluble collagen were also obtained from four adult and six aged menisci. Amino acid composition and carbohydrate contents were studied in insoluble collagen. The type of soluble collagen were analyzed with SDS disc electrophoresis. The amount of crosslinks in insoluble collagen was analyzed by the method of Masuda (1976) using automatic amino acid analyzer. The results obtained where shown as follow: 1) Solubility of collagen by pepsin decreased with aging on articular cartilages and menisci. In osteoarthritis and rheumatoid arthritis, the solubility of collagen by pepsin was different between the samples, and generally higher than that of collagen from the aged articular cartilages. 2) In respect to aldimine crosslinks of insoluble collagen, the dihydroxylysinonorleucine (DHLNL), hydroxylysinonorleucine (HLNL) and lysinonorleucine (LNL) increased with aging. DHLNL and HLNL were present in the nonreduced collagen in vitro. It was shown that the aldimine crosslinks had been already reduced in vivo. 3) The contents of carbohydrate of insoluble collagen from articular cartilage showed lower values than that of type II collagen as described previously. The hexosamine contents increased and those of uronic acid and hexose decreased with aging. In osteoarthritic and rheumatoid arthritic articular cartilages, the contents of uronic acid were lower than that of healthy aged group. The carbohydrate contents of menisci were similar to that of type I collagen. 4) concerning the type of collagen, healthy articular cartilages consisted of type II collagen. In collagen of aged cartilages and those of fibrillated and osteophytic cartilages in osteoarthritic and rheumatoid arthritic patients, the type II collagen were mixed with type I collagen ranging from 13.8% to 64.5%, although the analysis of articular cartilages in this study showed histological characteristics of hyaline cartilage. The type of soluble collagen in adult and aged menisci were composed of type I collagen in spite of aging.
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The analysis of the triggering mechanisms of the sperm acrosomal reaction was attempted by using multilamellar liposome model membranes. The permeability of liposomes composed of egg lecithin, cholesterol and dicetylphosphate was increased by addition of the acrosome reactive substance which was obtained from the jelly coat of the sea urchin, Hemicentrotus pulcherrimus. An identical but more rapid response was also observed with liposomes containing sialoglycosphingolipids isolated from spermatozoa of the sea urchin. CA++ ions enhanced the reaction with both types of liposomes. The multilamellar liposomes were found to be useful as a model membrane of the sperm acrosomal reaction, and an involvement of sialoglycosphingolipids in the sperm acrosomal reaction was suggested.
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The Vietnamese refugees have encountered a multitude of acute psychological, social, cultural, economic, and political upheavals. This study documents the Vietnamese perceptions of the life events that have swirled about them as well as the occurrences of these life events. Questionnaires were administered in 1975 and 1976 as part of an ongoing study. The expected high amount of life change in the year of the evacuation and resettlement (1975) continued into the following year (1976). Financial, life-style, work, spouse, and schooling problems continued to plague them and were increased in the second year. There was a positive correlation between life change and health status. The Vietnamese rank ordered the impact of life events in a fashion similar to the Americans, but there were differences in mean magnitude estimations. Substantial reductions in magnitude estimations at second administration of the Social Readjustment Rating Questionnaire indicated a change in the situational perception set with time.
A 33-year-old woman presented signs and symptoms which suggested mitral stenosis and insufficiency. Subsequent echocardiographic and angiographic testing demonstrated a left atrial tumor which was suspected clinically to be a left atrial myxoma. At surgery, the tumor was partially resected and histological examination revealed that the mass to be a malignant fibrous histiocytoma. At autopsy, the tumor was found to be localized in the heart, and there was no metastasis.
A clearly discriminable train of spikes was detected by ordinary silver disc electrodes fastened to the skin surface overlying m. vastus medialis during voluntary contraction in man. Some properties of these surface spikes were obtained. (1) Motor unit potentials detected by the inserted electrode loaded in the muscle closely under the fascia were found to be synchronized with the surface spikes. (2) The conduction velocity was around 3.5 m/s. (3) A starting point of the excitation, i.e., ,end-plate," was located at a point one-third of the observed length from the distal end in this particular case. (4) The conduction velocity showed a linear relationship with muscular temperature and Q10 approximately equal to 2.0 in the range of 17-31 degrees C. (5) The amplitude of the surface spikes decreased monotonously with increasing the distance between the source and electrode. (6) Wave forms and threshold values were highly reproducible. (7) Similar surface spikes have been found in six other muscles in the subject S.M. and in m. vastus medialis in five other subjects.
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