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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 739 records · Page 41Linked to original sources
PubMed1979

Ultrastructure and partial characterization of a regular array in the cell wall of Lactobacillus brevis.

The cell wall of Lactobacillus brevis was revealed by electron microscopy to have an outer layer composed of a regular array. The morphological unit of the regular array appeared to consist of four spherical subunits, each about 2 nm in diameter, which were arranged in a tetragonal pattern about 4.5 by 7.0 nm in dimension. The regular array was composed of the tetragonal units in rows in two directions at an angle of about 75 degrees to each other. The average spacing between the rows was about 10 nm in one direction and about 7 nm in the other. The tetragonally arranged subunits were removed from the cell wall by treatment with guanidine hydrochloride, urea, or sodium dodecyl sulfate (SDS) but not by the action of ethylenediaminetetraacetate, nonionic detergents, or proteolytic enzymes except pepsin. The regular subunits were shown to be composed of a protein with a molecular weight of about 51,000 by SDS-polyacrylamide gel electrophoresis.

Bromelains↗
PubMed1979

The eighth Frederick H. Verhoeff Lecture. presented by saiichi mishima, MD Behçet's disease in Japan: ophthalmologic aspects.

The problems of Behçet's disease in Japan have been reviewed with particular emphasis on the ophthalmologic aspects: the historical background for the Japanese works, diagnostic critieria, epidemiology, some statistics, ocular symptomatology, ocular histopathology, etiology, pathophysiology, and treatment. Behçet's disease is the most frequent entity in endogenous uveitis in Japan. Patients are found throughout the country, and the prevalence rate averages seven to eight per 100,000 population: the rate is higher in the northern than in the southern districts. The diagnosis is made on the basis of a combination of clinical symptoms that are divided into the major and minor criteria symptoms. The major criteria comprise the ocular involvement, aphthous ulcers of the oral mucous membrane, genital ulcers, and skin lesions. These symptoms recur often as attacks and the disease follows a chronic course. The ocular involvement is found in 83% to 95% in males and 67% to 73% in females; the male to female ratio in the number of patients is 1.78. Both into the anterior segment type and the fundus and panophthalmic types. The anterior segment type shows serous iridocyclitis with the classic type of hypopyon appearing in about 12% of the attacks. This type is found in about 20%, more often in females than in males, and the visual prognosis is more favorable than in the fundus and panophthalmic types. In the latter two types, attacks of retinal angitis resulting in intensive retinal edema, yellowish-white exudate, and hemorrhages recur particularly in the macular region, and the visual prognosis is poor. More than 50% of male patients lose visual acuity to less than 0.1 in five years, but this is the case in only 10% of female patients. Consequently, Behçet's disease is the cause of blindness in about 12% of acquired blindness in adults. The ocular histopathology during the attack is characterized by severe angitis with intensive infiltration of neutrophil leucocytes largely in the uveal tract and the retina; the latter is severely affected and loss of visual cells and other neural elements results. The etiology of this disease still remains unknown but genetic predisposition is suggested since this disease is strongly linked with HL-A-B5. Environmental factors are also considered. Various abnormalities are found in the blood chemistry, blood cells (particularly in neutrophil leucocytes), immunologic mechanism, fibrinolytic and blood clotting system, and hormonal system. Chemotractic factors are found in the aqueous humor. These changes are particulary enhanced just before and during the ocular attacks. Systemic corticosteroids are deleterious to the visual prognosis, but cyclophosphamide and colchicine appear to suppress attacks and help patients maintain the visual acuity. However, these drugs are toxic, particulary to the reproductive organs, and the patients must be informed of this side effect and be allowed to make a decision before they are used.

Adolescent↗
PubMed1978

Effect of human immunoglobulin preparations on Fc rosette formation between anti-D-coated erythrocytes and lymphocytes.

Human immunoglobulin (Ig) preparations were tested for their inhibitory effect on Fc rosette formation between anti-D-coated human erythrocytes and lymphocytes, as compared to their complement activating capacity. Both of the two biological activities ascribed to the sites in the Fc portion of the IgG molecules were found to be reduced in the pepsin-treated, as well as in the S-sulfonated Ig preparations, as compared to the activities of the normal human Ig preparation. In the plasmin-treated Ig preparation, which was found to be composed of three major components: plasmin-Fab, plasmin-Fc and plasmin-resistant IgG, the activity of inhibiting the Fc rosette formation was well retained, in contrast to its low complement activating capacity.

Binding Sites, Antibody↗
PubMed1977

Morphological changes in yeasts as a result of the action of 5-fluorocytosine.

The mode of action of 5-fluorocytosine on Candida albicans and Saccharomyces cerevisiae was studied with special reference to morphology and ultrastructure. Shortly after contact of yeast cells with 10 mug of 5-fluorocytosine per ml, marked enlargement of the cells occurred. The initial increase in cell size was almost the same with both yeast strains. As incubation proceeded, further increase in cell volume continued with C. albicans, whereas no further change in cell volume was observed with S. cerevisiae. An electron microscope examination of C. albicans cells after exposure to the drug revealed characteristic changes, consisting of an enlarged nucleus and a thin cell wall. The morphological changes were exactly comparable to those reported with inhibitors of deoxyribonucleic acid synthesis in mammalian cells and some bacteria.

Candida albicans↗
PubMed1977

Single dose response curves of normal cells in situ.

Analysis of data on the response of normal tissues (skin, lung, spinal cord, intestine, testis) to single and multifractionated irradiation schedules revealed the characteristics of the single dose survival curves of target cells responsible for skin, lung, and spinal cord reactions, and of stem cells of colonic, jejunal, gastric mucosae, and testis exposed in situ to relatively low doses of x- or gamma-rays. The single dose survival curves of these cells seem to be complex (unlike those of cells studied in vitro), that is, simply exponential in the initial portion up to approximately 250 rads, and downward-bending thereafter in a curve which includes one or two linear portions on a semilogarithmic scale.

Cells↗