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Biomedical subjects

T Miyoshi

Publications and source records attributed to T Miyoshi.

At least 271 records · Page 15Linked to original sources
PubMed1982

Peripheral neurology of the diabetic Chinese hamster.

Genetically diabetic Chinese hamsters were examined anatomically and physiologically for evidence of peripheral neuropathy. Control animals were from non-diabetic strains. Conduction velocities in both motor and sensory components of the hind limb nerves were reduced 16-22% in diabetic compared with control hamsters. However, there was no reduction in nerve fibre diameters or other signs of abnormal morphology that could be correlated with these physiological effects. It is concluded that the diabetic hamster is useful as a model of human diabetic peripheral neuropathy, but the analogy is not precise. The neuropathy of moderately diabetic hamsters is generally less severe than human diabetic neuropathy in its clinical stages.

Animals↗
PubMed1982

Combined effects of 5-fluorouracil and interferon on proliferation of human neoplastic cells in culture.

The growth inhibitory effects of the combination of 5-fluorouracil (5-FU) and human fibroblast interferon on human neoplastic cell lines and normal human fibroblasts were examined. The neoplastic cell lines used were HeLa (cervical carcinoma), MCF-7 (mammary carcinoma), WI-38 CT-1 (embryonic lung fibroblasts transformed in culture by 60Co gamma-ray irradiation), KMM-1 (myeloma), and Raji (Burkitt's lymphoma). The normal human cell line used was WI-38. The growth inhibitory effects were determined by measuring colony formation for HeLa, MCF-7, WI-38 CT-1, and WI-38 cells, and by measuring cell growth for KMM-1 and Raji cells. Each cell line showed different sensitivities to 5-FU or interferon. The combination of 5-FU and interferon showed synergistic inhibitory effects on the growth of HeLa, WI-38 CT-1, KMM-1, and Raji cells. Neither synergistic nor additive growth inhibitory effects of the combination of 5-FU and interferon were observed in MCF-7 and WI-38 cells.

Animals↗
PubMed1982

[Combined effects of 5-fluorouracil and interferon on proliferation of human neoplastic cells in culture].

Potentiation of the cytotoxic effects of 5-fluorouracil (5-FU) by interferon on human tumor cells was examined. The human neoplastic cell lines used were HeLa (uterine cervical cancer), MCF-7 (mammary cancer), WI-38 CT-1 (embryonic lung fibroblasts transformed in culture by Co-60 gamma-ray irradiation), KMM-1 (myeloma), and Raji (Burkitt's lymphoma). As a normal human cell strain, WI-38 (embryonic lung fibroblasts) was used. The cytotoxic effects were determined by colony formation. Each cell line was different in sensitivity to interferon or 5-FU. Interferon potentiated synergistically the cytotoxic effects of 5-FU on HeLa, WI-38 CT-1, and KMM-1 cells. In the case of Raji cells, the cytotoxic effects of the combination of interferon and 5-FU were additive. Neither synergistic nor additive lethal effects of the combination of the two agents were observed in MCF-7 and WI-38 cells. The present results indicate a possibility that a combined treatment with interferon and 5-FU may be effective in certain types of human cancers.

Cell Division↗
PubMed1982

[Induced rat ovarian carcinoma showing mainly squamous components--an experimental approach to common epithelial tumors].

Female Wistar strain rats were treated with a chemical carcinogen DMBA (7,12-Dimethylbenz (a) anthracene) implanted directly into their ovary. In this method of tumor induction, adenocarcinoma commonly developed in the ovary by the direct carcinogenic effect of DMBA during a 30 weeks observation period. However, two cases of primary ovarian carcinoma showing mainly squamous components have been found in a recent experiments. The histological characteristics of these indicated that they were adenoacanthoma and adenosquamous cell carcinoma and both were derived ultimately from the ovarian surface epithelium with interposition of endometrioid type tumor. These two cases of experimental rat ovarian cancer consist of mainly squamous element are studied morphologically and their histogenesis is discussed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Dissociation of the eyes in saccadic movement.

In horizontal saccades, abduction and adduction are not conjugate. Abduction starts shortly before adduction and reaches the turning point shortly after abduction. The duration in binocular recording is much shorter than in monocular recordings. The abducting eye has a tendency to move gradually on the new target. The adducting eye has, on the contrary, a tendency to overshoot. The characteristics of quick phases of horizontal optokinetic nystagmus, in which both eyes jump disconjugately to the new target, are similar to those of horizontal saccades. The main cause of this disparity may be a difference in neural mechanisms between abduction and adduction. Vertical saccades are not disconjugate.

Adult↗
PubMed1980

Primary extramedullary plasmacytoma of submaxillary lymph node.

A case of extramedullary plasmacytoma originating in the left submaxillary lymph node in a 63-year-old man was reported. The diagnosis of plasmacytoma was made on the basis of a monoclonal proliferation of IgG, K type of plasma cells by means of immune antibody staining. About 70% of extramedullary plasmacytoma cases have been reported to have a primary lesion in the upper respiratory tract and the oral cavity with cervical lymph node metastases in 8-30%. The present case was considered to be of submaxillary lymph node origin in view of failure of various examinations to detect lesions in the oral cavity and the upper part of the respiratory tract.

Humans↗
PubMed1980

Biosynthesis of bicyclomycin. I. Appearance of aerial mycelia negative strains (am-).

The degeneration of bicyclomycin-producing strains of Streptomyces sapporonensis resulted in sharply depressed bicyclomycin formation in a large scale fermentation. Degenerated strains, whose productivities were only 1/30 to 1/100 of normal strains, could not form aerial mycelia on glucose-BENNETT's agar; they were aerial mycelia negative strains (am-). Repeated transfers of culture, treatment of mycelia with acriflavin, mechanical agitation shock on mycelia or higher growth conditions stimulated the degeneration of producing strains, suggesting the involvement of extrachromosomal elements or plasmids in biosynthesis of bicyclomycin. Shake flask fermentation inoculated with a mixture of a normal high-producing strain and a degenerated low-producing strain resulted in sharply depressed bicyclomycin formation in proportion to the increase of low-producing strain added. It appears that the low-producing strain outgrew the high-producing strain.

Acriflavine↗
PubMed1980

Biosynthesis of bicyclomycin. II. Biosynthetic conditions and incorporation of radioactive precursors into bicyclomycin by washed mycelium.

The biosynthesis of bicyclomycin by Streptomyces sapporonensis was studied using suspensions of washed mycelium. Nicotinamide and Fe2+ were found to be essential cofactors in the biosynthesis. Production of bicyclomycin was enhanced most effectively in the presence of equal moles of L-leucine and L-isoleucine, which in experiments with radioactively labeled compounds were found to be incorporated into bicyclomycin at equivalent rates. These facts strongly suggest that bicyclomycin biosynthesis involves coupling of equal moles of these two amino acids.

Amino Acids↗
PubMed1979

Microvasculature of rabbit muscle spindles.

The microvasculature of the muscle spindle and its relationship to the microcirculation of teniussimus extrafusal muscle is described. Muscle spindles lie in close proximity and parallel to the central artery, vein, and nerve. The arterioles to spindle capillaries are third to fourth order branches of the central artery, whereas most arterioles to extrafusal capillaries are sixth to eighth order. Two or three capillaries enter each spindle. At least one entry consistently was encountered in the equatorial area near the sensory endings. Branches of intrafusal capillaries run longitudinally, anastomose with each other, and cradle the sensory zone in a longitudinal capillary loop. Capillaries in muscle spindles are larger than those in extrafusal muscle. These characteristic features are presumed to enhance the capability of these capillaries to provide sufficient circulation to the spindle, particularly to the region of the sensory endings.

Animals↗
PubMed1979

Morphometric comparison of capillaries in muscle spindles, nerve, and muscle.

Morphometric study was performed on transverse sections of microdissected muscle spindles from rabbit tenuissimus muscles. It showed a statistically significant difference in size and structure between the intrafusal capillaries and those of extrafusal muscle. The former are larger in diameter, circumference, and area due to a proportionate increase in the number of endothelial cells. Vesicles within spindle endothelial cells are fewer, mitochondrial counts are greater, but in proportion to the increased number of endothelial cells, intercellular junctions are tight and pericyte coverage is greater. The basement membrane around endothelial cells and pericytes is thicker and more often multilayered. The endoneurial capillaries of tenuissimus intramuscular nerve are morphologically identical to intrafusal capillaries. The similarity of the capillaries of spindles to those in brain suggests that a blood-nervous system barrier extends from brain into the peripheral nerves and muscle spindles.

Animals↗
PubMed1979

Optokinetic nystagmus in artificial hemianopsy.

Optokinetic nystagmus in cases of artificial hemianopsy was studied. Hemianopsy was produced by using a combination of a projector, an erasing device and DC ENG. The effect of the condition of foveal vision in hemianopsy, whether reserved or involved, was discussed. When foveal vision was reserved, nystagmus during stimulation in cases of hemianopsy was essentially the same as in the normal eye. In cases of hemianopsy in which foveal vision was involved, there was a remarkable difference between the mystagmus induced by foveofugal stimulation and that induced by foveopetal stimulation. In the former case the nystagmus was very fine and irregular, in spite of the fact that the nystagmus was well induced (it was nearly the same as in the normal eye in the latter case). Foveal vision is very important for the formation of the slow component of optokinetic nystagmus. Foveopetal movement of the image on the peripheral retina is very important for the formation of the quick component. Foveofugal movement on the peripheral retinal has, on the contrary, only a small effect in attracting the eye.

Eye Movements↗