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Biomedical subjects

Y Oguchi

Publications and source records attributed to Y Oguchi.

At least 145 records · Page 8Linked to original sources
PubMed1984

Effects of stimulus contrast on binocular VER.

The effect of stimulus contrast changes on the binocular visual evoked response (VER) was investigated using pattern reversal VER, dichoptic stimulation, and Fast Fourier Transform. When the stimulus contrast was changed binocularly, the monocular components increased as the contrast increased. The binocular component first appeared at the level of 10% contrast; its magnitude was stable under all recording conditions. When the stimulus contrast was changed monocularly, the eye that received the higher contrast stimulation showed more power in the power spectrum. The binocular component appeared even when the difference in contrast between the two eyes was large. The magnitude of the binocular component was stable under all recording conditions. We concluded that the binocular and the monocular components differ in the magnitude of their responses to a contrast change and speculate that the pathways responsible for the two components are not identical.

Adult↗
PubMed1983

Fractionation of mouse cytotoxic T cells by use of lectins.

Mouse cytotoxic T lymphocytes (CTLs), induced in vivo and in vitro in mixed-lymphocyte cultures, were fractionated into agglutinated and unagglutinated cells by use of various lectins. Cytolytic activity was enriched in the cell fraction agglutinated by various 2-acetamido-2-deoxy-alpha-D-galactopyranose-specific lectins, namely, Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA), and Phaseolus limensis agglutinin (LBA). Only a little cytolytic activity remained in the unagglutinated cell fraction. Furthermore, the relationship between the binding of lectins and the cytolytic activity in various CTL cell lines was investigated with a fluorescence-activated cell sorter, and high-rank correlation was found between the cytolytic activity of these CTL cell-lines and the binding of DBA or HPA to them, but weaker rank correlation in the cases of LBA and peanut agglutinin (PNA). DBA was found to bind to almost all cells of interleukin-2-dependent CTL cell-lines tested. Although the DBA-positive CTL cell-lines have strong cytolytic activity, the DBA-negative cells, which consist of a small proportion of the CTLs, also exhibited cytolytic activity. Thus, the major part of CTLs has binding sites for alpha-D-GalNAc-specific lectins, particularly for DBA, and this lectin is useful for the enrichment of CTLs. However, the binding sites for DBA cannot be regarded as an exclusive differential marker for CTLs.

Animals↗
PubMed1983

Common channel syndrome--diagnosis with endoscopic retrograde cholangiopancreatography and surgical management.

Six patients with intermittent bouts of vomiting, fever, abdominal pain, and jaundice beginning in infancy or early childhood were all demonstrated by endoscopic retrograde cholangiopancreatography to have an anomalous junction of the pancreaticobiliary ductal system with the formation of a characteristic long common channel. A varying degree of dilatation of the bile duct also was noted. Resection of choledochus followed by hepaticoduodenostomy was performed with satisfactory results invariably in all cases. The existence of a pathologic entity that might reasonably be designated "common channel syndrome" is discussed with some comments on its relationship with dilatation of the bile duct (choledochal cyst) as well as on the recommendable method of surgical treatment.

Child↗
PubMed1983

Involution of the thymus in tumor-bearing mice and its restoration by PSK.

In Balb/C mice, the size and weight of the thymus and the number of thymus cells were reduced 1 week after the subcutaneous inoculation of Meth A fibrosarcoma. These changes were prevented by the intraperitoneal administration of PSK. In normal mice, the majority of thymus cells are large and the minority are small as demonstrated by analysis with a fluorescence activated cell sorter. In tumor-bearing mice, the number of large cells are decreased and the number of small cells are relatively increased. PSK prevented such a modulation in tumor-bearing mice.

Animals↗
PubMed1982

Effect of p-aminobenzoic acid N-xyloside sodium salt (K-247) on metabolism and functions of normal lymphocytes and leukemic cells.

An N-xyloside derivative of p-aminobenzoic acid, K-247, was investigated for the ability to induce changes of Phospholipid metabolism and membrane transport in murine splenic lymphocytes and leukemic cells. K-247 induced an increase of [3H] methyl group incorporation into phospholipid in both normal lymphocytes and leukemic cells (L-1210 and M1 cells). However, K-247 accelerated the turnover of phosphatidylinositol (PI) measured by [32P] incorporation into PI in L-1210 cells and Ml cells but not in normal lymphocytes. 45Ca2+ influx into normal lymphocytes and leukemic cells was also increased by K-247. A methyltransferase inhibitor, 5'-deoxy-5'-S-isobutyl adenosine (SIBA), suppressed both the increase of phospholipid methylation and that of Ca2+ influx. It seemed that Ca2+ transport might be regulated by membrane phospholipid methylation. On the other hand, K-247 was found to suppress [3H] aminoisobutylic acid (AIB) uptake into L-1210 cells and Ml cells. Protein synthesis in L-1210 cells and Ml cells slightly decreased but RNA and DNA syntheses in both normal and leukemic cells were not affected by K-247. These results suggest that K-247 mainly acts on cell membranes, which are more sensitive to K-247 in leukemic cells than in normal lymphocytes. K-247 also induced differentiation of Ml cells into macrophages and granulocytes with phagocytic activity and morphological characteristics. Moreover, K-247 elevated the Con A response of murine thymocytes, most of which were immature T cells and had low reactivity to Con A, and caused a decrease of Thy 1.2 antigen on thymocytes. It seemed that K-247 also affected maturation of thymocytes.

4-Aminobenzoic Acid↗
PubMed1981

"Common channel syndrome"--anomalous junction of the pancreatico-biliary ductal system.

A 7-year-old girl with a 3-year history of intermittent bouts of abdominal pain and jaundice underwent endoscopic retrograde cholangio-pancreatography, which revealed an anomalous junction of the pancreatico-biliary ductal system (bile duct dilatation being virtually non-existent). These abdominal symptoms being considered to be attributable to the anomaly, resection of choledochus followed by hepatico-duodenostomy was performed. Now, one and a half years after operation, the patient is entirely asymptomatic. The legitimacy of "common channel syndrome" as an independent pathologic entity was proposed and the necessity of surgical treatment in its successful management was stressed.

Child↗
PubMed1980

Age-dependent changes of the levels of suppressor and helper T cells in New Zealand black mice.

Peanut agglutinin-positive (PNA+) T cells in concanavalin A (Con A) activated spleen cells were found to markedly decrease with age in New Zealand black (NZB) mice but not in non-autoimmune strains, using a fluorescence activated cell sorter (FACS II). On the other hand Limulus polyphemus agglutinin positive (LPA+) T cells in Lens culinaris agglutinin (LcA) activated spleen cells were found to gradually decrease both in NZB and non-autoimmune strains. Since PNA has previously been shown to selectively label Con A-induced suppressor T cells, these results support the previous observation by other investigators that suppressor T cell function declines with age in NZB mice. It was also demonstrated that the level of one of natural thymocytotoxic autoantibodies (NTA-2) developed in NZB mouse serum, which had been shown to have a similar carbohydrate binding specificity to PNA and to exert a cytotoxic effect specifically against suppressor T cells, was elevated early in the life of NZB mice. These results suggest a possible role of NTA-2 in the decline of PNA+-T cells in vivo.

Agglutinins↗