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Biomedical subjects

Y Mitsui

Publications and source records attributed to Y Mitsui.

At least 325 records · Page 18Linked to original sources
PubMed1981

An electromyographic study of esotropia.

Under general anaesthesia the eye position of esotropia generally moved divergently. When retrobulbar anaesthesia was added bilaterally, the eye position moved further in the same direction. In the electromyogram under general anaesthesia the 4 horizontal recti were silent in controls. In many cases of esotropia, however, both medial recti showed a considerable amount of discharge under general anaesthesia. When retrobulbar anaesthesia was superimposed on one eye, the discharge from its medial rectus tapered off and, reciprocally, that of the opposite eye increased. These facts may suggest that proprioception plays in the development of esotropia.

Adolescent↗
PubMed1981

Proprioception and exodeviations.

When a slight adductive force is applied by forceps to the straight or master eye in exotropia, the exodeviated or slave eye assumes the straight position. The nature of this phenomenon was studied. The reflex occurred in an all-or-none form and showed little dose response, that is, the slave eye did not adduct beyond the straight position even if an extreme forced adduction was applied to the master eye. Once the slave eye assumed the straight position by the reflex it maintained this position, even when the master eye was covered, except when the master eye was released from the forced adduction. This reflex movement response occurred promptly on repeated forced adduction at 9 Hz on the master eye, while the visual movement of the eye was limited to follow 1 Hz movement of the target. The reflex occurred readily in the light but hardly at all in the dark. From these facts the authors conclude that the reflex is brought about as a result of interaction between the proprioceptive impulse and the visual input, where the former may chiefly constitute the signal, while the latter restricts the threshold of the reflex pathway.

Electrooculography↗
PubMed1981

Preliminary crystal structure analysis of a microbial, guanine-specific ribonuclease St at 2.5 A resolution.

The three-dimensional structure of Ribonuclease St (RNase St), the extracellular ribonuclease from Streptomyces erythreus, has been deduced based on a preliminary electron density map at 2.5 A resolution. RNase St has a substrate specificity similar to ribonuclease T1 which catalyzes the splitting of the phosphodiester bond of guanylic acid. Crystals grown as diamond plates have space group C2 with unit cell parameters a=88.4, b=33.0, c=69.0 A, beta = 98.4 degrees having two enzyme molecules per asymmetric unit. Phases were obtained by use of KAu(CN)4, phenylmercuric acetate and UO2 (CH3COO)2. The overall dimensions of the molecule are 40 X 30 X 25 A. The most prominent secondary structural features are two turns of alpha-helix and a three strand stretch of antiparallel beta-sheet. The alpha-carbon backbone of RNase St seems to have no apparent correlation with that of ribonuclease A.

Models, Molecular↗
PubMed1980

Cell-surface changes accompanying aging in human diploid fibroblasts: effects of tissue, donor age and genotype.

The generality of age-related changes in concanavalin A (Con A)-mediated red blood cell (RBC) adsorption to human diploid fibroblasts was investigated on fibroblast-like cells from fetal lung, heart, liver, skin and muscle tissues. All the cells examined showed the continuous increase from early passages in RBC adsorption with the RBC coating method (in which Con A-coated RBCs are adsorbed to fibroblasts) and the incraease only at phase III with the fibroblast coating method (in which RBCs are adsorbed to Con A-coated fibroblasts). All of the four strains of lung fibroblasts gave nearly the same extent of the age-related change in RBC adsorption, when expressed as a function of percentage life span consumed, indicating that the change in RBC adsorption is independent of genetic heterogeneity and conditions of primary culture. Liver and heart fibroblasts also gave results similar to those of lung fibroblasts. However, skin and muscle fibroblasts were lower in their RBC adsorption capacity throughout the life span. The continuous age-related increase in RBC adsorption to these cells could be sensitized by using glutaraldehyde-prefixed RBCs, trypsinized RBCs or phytohemagglutinin P in place of Con A. The relevance of the phenotype of in vitro aging revealed by RBC adsorption to in vivo aging was also demonstrated on skin fibroblasts from different ages of donors using glutaraldehyde-prefixed RBCs. In addition, fibroblasts from patients with Werner's syndrome, an hereditary disease manifested by early and widespread degenerative changes, showed senescent phenotype in RBC adsorption even at early passages.

Adult↗
PubMed1980

Solvent accessibility and microenvironment in a bacterial protein proteinase inhibitor SSI (Streptomyces subtilisin inhibitor).

Solvent accessibility (Lee, B. & Richards, F.M. (1971) J. Mol. Biol. 55, 379-400) was calculated for each atom of a bacterial protein proteinase inhibitor SSI (Streptomyces subtilisin inhibitor) based on crystallographic coordinates. Mainly based on this information, various chemical and spectroscopic (UV, Raman, NMR) observations made on the microenvironments of cystines, methionines, tryptophan, histidines, and tyrosines of SSI in solution were evaluated. Crystallographic data and the latter two sets of data were mainly at least qualitatively consistent with each other. These data include (1) the conformation of the two disulfide bridges, (2) the flexibility of the three methionyl side chains, (3) the extent of exposure of the indole ring of a tryptophan, (4) the environment of the two histidines, (5) the environment of the tyrosines, and (6) the hydrogen-deuterium exchangeability of peptide NH's. However, the extents of exposure of tyrosines deduced by solvent perturbation UV difference spectroscopy were significantly larger than those based on solvent accessibility calculations. Possible reasons for this discrepancy are discussed.

Bacterial Proteins↗
PubMed1980

Cell, tissue and organ banks in Japan with special reference to the study of premature aging.

Cell and tissue banking facilities exist in Japan in a) 7 laboratories of national institutions, for the conservation of living organisms, b) the Tokyo Metropolitan Institute of Gerontology, operating its own bank of cultured human cells for aging research, c) the Institute of Physical and Chemical Research which is performing pilot experiments for cell research and cell banking, and d) more than 50 laboratories operating small-scale repositories in the fields of cancer research, virology, genetics, gerontology, radiation biology, cell biology, and cell physiology. Except for several eye banks, no organ banks have yet been developed in Japan. As an example of cell and tissue banking, some details for studying a premature aging syndrome, i.e., Wistar's syndrome (WS) is shown. Four cases of autopsied WS patients and more than 20 clinically traced WS patients have been reported in Japan. At present, cultured skin cells from more than 20 WS patients and skin tissues from several WS patients for the initiation of culture, are on deposit and under investigation.

Cell Line↗