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Biomedical subjects

S Toyoshima

Publications and source records attributed to S Toyoshima.

At least 145 records · Page 8Linked to original sources
PubMed1983

CT's capability in detecting advanced gastric cancer.

Upper GI series and CT scans of 23 patients with advanced gastric cancer were reviewed and correlated to determine CT's capability in detecting gastric tumors. The CT images of the gastric carcinomas revealed either a mass or thickening of the wall. These abnormalities were present in 78% of the cases whereas CT demonstrated a "mass" in 52%. The most difficult site for CT diagnosis of gastric cancer was the antrum. Diagnostic accuracy of CT in evaluating tumor invasion of adjacent structures is reportedly high. However, in the present study this was not necessarily true. In 4 of 5 patients whose gastric tumors proved unresectable, CT failed to reveal adjacent invasion. This suggests that CT is not always reliable in predicting surgical resectability.

Aged↗
PubMed1983

Incorporation of bile acid of low concentration into model and biological membranes studied by 2H and 31P NMR.

We have analyzed the manner of incorporation of bile acid into lipid bilayers and resultant perturbation of the bilayer structure with lower bile acid/lipid ratios relevant to the physiological conditions (approximately 1 mM) by 2H and 31P NMR methods, as an aid to understanding the possible role as an endogenous tumor promoter in colon cancer besides the primary physiological function of solubilizing lipids. On the basis of the 2H quadrupole splittings of [6,6,7,7,8-2H5]deoxycholate and [11,11,12,12-2H4]chenodeoxycholate in the presence of lamellar multibilayers of egg yolk lecithin, these bile acids were found to be incorporated in such a manner that the B-D rings lie parallel with the normal of the bilayers when the ratio of the bile acid to lipid is low (less than 0.11). When the ratio is increased, these bile acid molecules are not dispersed entirely in the bilayer but aggregate to form micelles with lipids. Further, we studied the resultant perturbation of the multibilayers of egg yolk lecithin analyzed by using the 2H quadrupole splitting of [18,18,18-2H3]stearic acid as a probe and by 31P chemical shift anisotropy. We found that the bilayer structure is retained even at the bile acid-to-lipid ratio of 0.25, although a small amount of an isotropic phase appeared such as small vesicles and micelles. The molecular ordering of fatty acyl chains was rather enhanced by the presence of 1 mM deoxycholate in erythrocyte ghosts as seen from the 2H quadrupole splitting of [16,16,16-2H3]palmitic acid, although deoxycholate caused hemolysis in this condition. The former observation can be explained by the way the lipid-protein interaction is modified by deoxycholate located in the interface between the lipids and proteins.

Animals↗
PubMed1983

Recurrent pheochromocytoma associated with glucagonoma. A case report.

We treated a hypertensive patient with recurrent pheochromocytoma (paraganglioma) associated with glucagonoma. No clinical symptom of glucagonoma was found and it could be detected only by a slight elevation of plasma immunoreactive glucagon (IRG) while the extirpated pancreatic tumor contained much IRG. This case could not be classified as either multiple endocrine neoplasia (MEN) type I or type II.

Adenoma, Islet Cell↗
PubMed1983

The importance of determining stable glycosylated hemoglobin in diabetics: confusions are caused by the nomenclature of glycohemoglobin as HbA1C or HbA1 in its evaluation.

Specimens of HbA1C from human hemolysate contain more than six minor components which cannot be separated by conventional methods. These components have differing characteristic properties and their levels fluctuate depending on the time the blood is drawn and the method of sample preparation used. HbA1C exhibits unreasonable fluctuation and unexpectedly high levels and is therefore not an accurate indicator of long-term blood glucose control. The six components of HbA1C were resolved by our new chromatographic technique using IEX-530, and designated by their eluting position and properties; HbF6, L-GHb7, St-GHb8, L-GHb9, Fr10, and Fr11. HbF6 was alkaline resistant. L-GHb7 and L-GHg9 were easily removed by treatment with saline or semicarbazide and increased after incubation with glucose. The level of L-GHb7 in the blood showed rapid and varied fluctuation on OGTT in both diabetics and control subjects. More than 2% HbF6 and L-GHb7 was present in 13.3% of the control group (n = 57) and in 51.4% of the IDDM group (n = 45). St-GHb8, which was a major component of HbA1C, was not affected by pretreatment with saline, semicarbazide or glucose in vitro. The level of St-GHb8 in the blood showed little change on OGTT. HbA1C, hitherto referred to as one stable component, is an incorrect term used to denote the index of long-term blood glucose control. It is important and warranted to use the level of stable glycohemoglobin (St-GHb8) in future determinations following proper analytical methods.

Blood Glucose↗
PubMed1983

Establishment and characterization of continuous murine non-specific suppressor T cell lines.

Normal mouse spleen cells were activated by Con A and suppressor T cells were enriched by the use of peanut agglutinin (PNA). Cells of the enriched suppressor T cell fraction were further cultured in a medium containing T cell growth factor (TCGF) and the suppressor T cell lines were established. These cell lines have been growing in culture for more than one year and retained surface characteristics of Thy-1+, Lyt-1-, 2- and bear receptor sites for PNA. The suppressor clones exerted an inhibitory effect on in vitro antigen specific and antigen nonspecific PFC responses. The culture supernatant of these clones had a suppressive effect on the in vitro humoral responses, indicating that a soluble factor mediates at least partly the suppressive activity of the antigen nonspecific suppressor T cells. Moreover, it was revealed that the suppressor cells must exist at an early stage of PFC culture to exert their activity.

Animals↗
PubMed1983

Antiviral effects of amino acid derivatives with the fluorene substituent on murine leukemia viruses.

Two new amino acid derivatives with the fluorene substituent, when administered ip to female inbred ICR-CD1 mice inoculated with Friend murine leukemia virus, significantly inhibited virus-induced splenomegaly, reduced viable virus titers in spleen and plasma, and significantly prolonged survival time. These compounds also inhibited multiplication of the strains of the Friend and Moloney murine leukemia viruses in a cell culture system. The action of these compounds on murine leukemia virus was presumely different from that of tilorone.

Animals↗
PubMed1982

The relationship between phospholipid methylation and calcium influx in murine lymphocytes stimulated with native and modified Con A.

Native Con A and two chemical derivatives, divalent dimeric Con A and monovalent dimeric Con A. induced a transient increase of phospholipid methylation, Ca2+ influx, and also increased DNA synthesis in murine lymphocytes. For each of the individual mitogens, the dose-response curves for these three activities were very similar. However, there were major differences between the dose-response curves for Con A and each of its two chemical derivatives. On the other hand, the time course of phospholipid methylation for each lectin reached a maximum at about 10 min after the addition of lectin, and then gradually decreased to control levels. In like manner, Ca2+ influx reached its maximum at approximately 5 min. The lectin-stimulated increase in phospholipid methylation occurred in calcium-free medium, while the inhibitor of phospholipid methylation, 3-deaza-SIBA, also suppressed the increased calcium influx. This suggests that the Ca2+ influx might be regulated by early phospholipid methylation. Further, in the absence of calcium, the methylated phospholipids do not undergo Con A-accelerated breakdown by phospholipase A2. This suggests that the increased influx of calcium is necessary for the activation of phospholipase A2, an enzyme that hydrolyses methylated phospholipids to yield arachidonic acid and lysolecithin. Blocking any of these biochemical steps also blocked subsequent DNA synthesis, suggesting that the pathway may be required for the activation of lymphocytes.

Animals↗
PubMed1982

Morphological varieties and host ranges of Vibrio parahaemolyticus bacteriophages isolated from seawater.

Eighteen bacteriophages lytic for Vibrio parahaemolyticus were isolated from seawater, and their ultrastructure was examined by electron microscopy. Based on the phage morphology, they were classified in four groups. Group I phages consisted of a hexagonal head and a tail with a contractile sheath. All the phages of the other three groups had a relatively long, noncontractile tail, but there were differences in the head structure among these phages. The phages of groups II and III had a hexagonal head and an elongated polyhedral head, respectively. Group IV phages exhibited a unique hexagonal head with knoblike projections. There appeared to be no correlation between the O and K serotypes of V. parahaemolyticus strains and the host ranges of the phages. The phages had varying sensitivities to heat and organic solvents.

Bacteriophages↗
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↗
PubMed1982

[Antitumor effects of organic silicone compounds (IV). Antitumor effects of SDK-50 and SDK-47].

From the results of the 1st and 2nd screening as to the antitumor effect of organosilica compounds, two compounds, namely, SDK-50 (2-piperidinoethyl-phenyldimethyl-silane) and SDK-47 (3-N-2-propenylamino) propyltrimethyl-silane were selected. These two compounds were further tested by using the solid form cancer of Ehrlich, sarcoma-180 and Lewis lung carcinoma in mice and moreover the rats bearing ascites hepatomas. AH-13, 130, 272, 44, 66F, 66, 7974, 41-C, 60-C and 109A. From the summarized data, it may be said that the effect of SDK-50 is relatively superior to SDK-47. In addition of the inhibitory effect on cancer cells, it was found that SDK-50 possesses an activating effect of delayed type hypersensitivity. This effect of SDK-50 was equivalent to PSK or SPG.

Adjuvants, Immunologic↗
PubMed1981

Mechanism of the concanavalin A-induced change of membrane fluidity of chicken erythrocytes.

When chicken erythrocytes labeled with a stearic acid derivative spin label was treated with concanavalin A (Con A), ESR spectra showed a change in the peaks due to the labels in membrane lipids, indicating an increase of membrane lipid fluidity. Addition of Con A increased the fluidity rapidly. This change was reversible only up to 30 min after adding Con A, and thereafter it gradually became irreversible. However, if the erythrocytes were treated with cytochalasin B and methyl alpha-D-mannoside, a complete return of fluidity to the normal level could be observed at any stage after the binding of Con A. The observation of freeze-fracture replicas of erythrocyte membranes by transmission electron microscopy also showed that the redistribution of intramembranous particles gradually became irreversible after exposure to Con A. These results suggest that the microfilament-like system, which modulates the distribution of cell surface receptors for Con A, participates in the modulation of membrane fluidity. Phospholipid methylation of chicken erythrocyte membrane was stimulated immediately after the binding of Con A. A methyltransferase inhibitor, 5'-deoxy-5'-S-isobutyl adenosine, abolished the increase of membrane fluidity within the first 10 min and also that occurring later than 60 min after adding Con A, but it was without effect on the elevated fluidity found between 20 and 60 min. Removal of extracellular Ca2+ had an inhibitory effect on the lasting increase of fluidity. These results suggest that the first increase of membrane fluidity by Con A may be caused by phospholipid methylation, while the second increase may depend on the rearrangement of Con A receptor glycoproteins through cross-linking wit Con A. The irreversible part of the membrane fluidity increase probably depends on Ca2+ influx, phospholipid methylation, and peripheral membrane proteins which constitute the microfilament-like system at the membrane inner surface.

Animals↗
PubMed1981

Mechanism of inactivation of hepatitis B surface antigen by N alpha-cocoyl-L-arginine ethyl ester.

The mechanism of N alpha-cocoyl-L-arginine ethyl ester (CAE) in the inactivation of hepatitis B surface antigen (HBsAg) was investigated. The CAE increased the density of HBsAg, and particles of the antigen were destroyed in amorphous clusters, suggesting that CAE influences the lipid components of HBsAg. The lipid components such as cholesterol and phospholipid were mostly removed from the antigen by the treatment with CAE. N alpha-Lauroyl-L-[U-14C] arginine ethyl ester (LAE), a principal component of CAE, became tightly bound to HBsAg in place of the lipid components. The binding amounts of LAE in the HBsAg-LAE complex reached 3.04 +/- 0.44 microgram/mg of protein. The formation of the complex was not influenced by the presence of CAE-related compounds such as L-arginine, L-arginine ethyl ester, and N alpha-cocoyl-L-arginine. Treatment with mercaptoethanolurea, guanidine hydrochloride, and some detergents failed to resolve appreciably the labeled LAE from the labeled complex. All attempts to reactivate the CAE-treated HBsAg and to restore it morphologically from the denatured aggregates were unsuccessful. These results indicate that CAE tightly binds to HBsAg, followed by formation of stable aggregates of the denatured HBsAg-CAE complex.

Arginine↗
PubMed1981

Isolation and characterization of a mitogenic substance for murine and human B lymphocytes from Ulex europeus seeds.

A mitogenic substance, which stimulates murine and human B lymphocytes, has been isolated from the seeds of Ulex europeus. The m.w. of this mitogen was estimated to be approximately 100,000 by sodium dodecyl sulfate disc gel electrophoresis. Under physiologic conditions Ulex mitogen was in the form of a polymer. The isolated mitogen was found to contain 80% carbohydrate, in which glucose, galactose, and rhamnose were the predominant sugars. The carbohydrate portion of the mitogen could be responsible for the mitogenic activity, since the activity was destroyed by periodate treatment but not by protease digestion. It is unlikely that the mitogenic activity is due to the contamination by lipopolysaccharide (LPS), because Ulex mitogen strongly activated spleen cells from C3H/HeJ mice and did not contain a detectable amount of fatty acid. Spleen cells from nude mice, T-depleted spleen cells from conventional mice, or T-depleted spleen cells from conventional mice, or T-depleted lymphocytes from human peripheral blood responded as strongly as lymphocytes (T + B) from normal origin as measured by 3H-thymidine incorporation. It seems that the mitogenic effect is primarily on B cells. Ulex mitogen also induced the increase of immunoglobulin synthesis in murine and human B cells.

Animals↗