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Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 631 records · Page 35Linked to original sources
PubMed1987

Eicosanoid production by peritoneal and splenic macrophages in mice depleted of bone marrow by 89Sr.

Previous studies showed that the prostaglandin-forming macrophages (M phi) induced in the spleens of CBA/J mice by intraperitoneal administration of Corynebacterium parvum (CP) could not be demonstrated following the depletion of bone marrow and blood monocytes with 89Sr. The present study compares prostaglandin E2 (PGE2), leukotriene C4 (LTC4), and LTB4 release by splenic and resident peritoneal M phi in 89Sr-treated mice and 88Sr controls following in vivo CP and in vitro incubation with zymosan, calcium ionophore A23187, or phorbol ester (PMA). Intraperitoneal administration of CP resulted in the appearance of PGE2- and LTB4-releasing M phi in the spleens of control but not 89Sr mice. The incorporation and quantitative distribution of 3H-arachidonic acid into membrane lipids, however, were comparable in test and control mice. Neither zymosan nor any of the other stimulatory agents was able to effect significant release of PGE2 in vitro. No release of LTC4 by splenic M phi was detectable under experimental or control conditions. In contrast, the capacity of resident peritoneal M phi to release PGE2, LTC4, and LTB4 was apparently unaffected by 89Sr-induced bone marrow and monocyte depletion with virtually no demonstrable elicitation. Resident peritoneal M phi removed after CP in such mice showed a dramatic decrease in PGE2 release when incubated in vitro with zymosan, A23187, or PMA. These results, taken with earlier findings, demonstrate characteristically different phenotypic expression of metabolism of certain eicosanoids by splenic M phi from the spleen and the peritoneal cavity and suggest in addition that the induction of PGE2-synthesizing M phi in the spleen by CP is dependent on either an immigrant cell originating in the bone marrow or a regulatory agent derived from a bone marrow cell.

Animals↗
PubMed1986

Detection of metallothionein on nitrocellulose membrane using Western blotting technique and its application to identification of cadmium-binding proteins.

A convenient method for detecting metallothionein (MT) and other cadmium-binding proteins (Cd-BPs) in tissue cytosol was established. A sample that contains MT was separated on a sodium dodecyl sulfate-polyacrylamide gel and then electrophoretically transferred to a nitrocellulose membrane after reduction with 2-mercaptoethanol (2-ME) on the gel. The membrane was incubated in a buffer containing 109Cd and then subjected to autoradiography. MT-I and -II in rat liver cytosol were detected as radioactive bands together with a Cd-BP of 60,000 Da. On the other hand, three Cd-BPs of 40,000, 29,000, and 24,000 Da were detected in the cytosol when the reduction with 2-ME was omitted.

Animals↗
PubMed1986

Cytoplasmic surface ultrastructures of cardiac gap junctions as revealed by quick-freeze, deep-etch replicas.

Rapid-freeze, deep-etch, rotary-shadow replica studies were performed to examine the cytoplasmic surface membrane of the cardiac gap junctions of rats, mice, and guinea pigs. In quick-frozen fresh cardiac muscles, while the nonjunctional cytoplasmic surfaces were covered with filamentous materials, the cytoplasmic surface membrane continuous with freeze-fractured gap junction plaques were relatively free of such filaments and revealed particulate patterns. After brief rinsing in high K buffer, gap junction membranes showed granular substructures resembling a tiled surface made of round tiles of various sizes. After prolonged rinsing for more than 20 min, however, cytoplasmic surfaces of gap junctions became less particulate but rather smooth. The particulate substructures observed in the rapid-freeze deep-etch replicas may correspond to the fuzzy cytoplasmic layer in thin sections and serine protease sensitive peptide moiety in sodium dodecyl sulfate-polyacrylamide gel electrophoresis reported in isolated cardiac gap junction pellets. These cytoplasmic components, which are absent in liver gap junctions, seem to be specific in cardiac and neural gap junctions and may be related to the large electrical current passed by these junctions.

Animals↗
PubMed1986

Distribution of endothelial vesicles in the microvasculature of skeletal muscle and brain cortex of the rat, as demonstrated by tannic acid tracer analysis.

Ultrathin serial sectioning and labeling with tannic acid have demonstrated that most plasmalemmal vesicles of rat vascular endothelial cells are not free, but rather are conjoined in three dimensions to form racemose invaginations from the cell surfaces. To elucidate the distribution of vesicles in these microvascular endothelial cells, we have examined terminal arterioles, capillaries and post-capillary venules of rat skeletal muscle and brain cortex, using tannic acid labeling and stereological methods, and have determined the proportions of free vesicles and the vesicles of luminal and abluminal invaginations, as well as the numerical density of vesicles. In the case of capillaries, regional differences in distribution have also been studied. The ratio of free vesicles is 6-7% and is constant throughout the muscle microvasculature. The distribution (proportions and numerical densities) of vesicles in the brain and muscle microvascular endothelial cells shows regionally distinctive patterns. In rapid-frozen, freeze-substituted endothelial cells, there are almost as many fused vesicles as seen in chemically fixed cells. Therefore, aldehydes do not seem to induce membrane fusion, and the distribution of vesicles seems to be preserved by chemical fixation. The structure and function of plasmalemmal vesicles are discussed.

Animals↗
PubMed1986

Risk analysis of multiple environmental factors: radiation, zinc, cadmium, and calcium.

Simultaneous effects of four risk factors, i.e., radiation exposure at a sublethal dose and excessive administration of zinc or cadmium and calcium deprivation, were examined by animal experiments. Deaths among 360 mice within 30 days after the whole body irradiation of 524-617 rad gamma rays were observed under 36 experimental conditions set by all possible combinations of varied levels of the four risk factors. A similar experiment was conducted a month later to check the reproducibility by using another 360 mice. The reproducibility of the experiment was confirmed and therefore the data from the two experiments were pooled. The analysis of data based on a multiple logistic model suggested that administration of zinc acts protectively against radiation.

Animals↗
PubMed1986

Transfer function of right- and leftward eye movements in patients with unilateral labyrinth.

In patients with loss of unilateral labyrinthine function, the dynamic characteristics of rightward eye movement and leftward eye movement induced by the healthy labyrinth were displayed respectively. In patients who were examined within a few months after loss of unilateral labyrinthine function, the gain of eye movement toward the healthy labyrinth was low compared with that of eye movement toward the opposite direction. These differences in the gain were remarkable in the frequency range from 0.01 to 0.1 Hz. But those differences in the gain were not detected in patients who were examined more than 3 months after loss of unilateral labyrinthine function.

Adult↗
PubMed1986

A new platelet antigen system, Yuka/Yukb.

We report a new platelet antigen (Yukb) involved in a case of neonatal alloimmune thrombocytopenia (NAITP). This antigen is considered to be a product of an allele of the Yuk gene, another allele of which codes for Yuka which was involved in 2 cases of NAITP. The Yuka and Yukb antigens are not expressed on thrombasthenic platelets which suggests that these antigens are present on platelet glycoprotein IIb and/or IIIa. The gene frequencies for Yuka and Yukb in the Japanese population were estimated to be 0.0083 and 0.9917, respectively.

Alleles↗
PubMed1986

Yuka, a new platelet antigen involved in two cases of neonatal alloimmune thrombocytopenia.

We report a new platelet antigen (Yuka) defined by the sera of 2 mothers whose babies developed alloimmune thrombocytopenia. These antiplatelet antibodies were IgG detected by Mixed Passive Hemagglutination (MPHA). In the study of two families, the Yuka antigen was found to be inherited as an autosomal dominant trait. The frequency of the Yuka phenotype in the Japanese population was estimated to be 1.7% (5/300).

Blood Platelets↗