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Biomedical subjects

T Osawa

Publications and source records attributed to T Osawa.

At least 307 records · Page 17Linked to original sources
PubMed1986

Changes in thickness of collagen fibrils in the endo- and epineurium of the mouse sciatic nerve during development.

Changes in the diameter of collagen fibrils were observed with an electron microscope in the endo- and epineurium of sciatic nerves of mice during development from 12 days of gestation to 5 months after birth. It was noted that endoneurial collagen fibrils appeared in embryonic mice at 15 days of gestation, and at the same time, basal laminae began to appear sporadically on the Schwann cell plasmalemma. No fibroblasts were seen at this developmental stage. Collagen fibrils in the endoneurium remained as thin as they were when they first appeared, being in the narrow range of 250-300 A in diameter, while those in the epineurium became much thicker (400-450 A, 5 months after birth) as is also the case in dermal connective tissues. The present study shows that the endoneurial collagen fibrils were different in their developmental pattern from those of the epineurial or of other connective tissues, lending support to the concept that the endoneurial collagen fibrils are particular in nature, being so-called histological reticular fibers.

Animals↗
PubMed1986

Induction of in vitro antigen-specific antibody production against NIP-KLH in nonadherent cells derived from human peripheral blood mononuclear cells.

A primary in vitro antibody response to 4-hydroxy-3-iodo-5-nitrophenylacetyl keyhole limpet hemocyanin (NIP-KLH) by plastic dish nonadherent human peripheral blood mononuclear cells (PBMC) was examined. Nonadherent cells of most donors produced an anti-NIP antibody when they were cultured with the antigen at a cell density of 2.5 X 10(6)/ml in the presence of Staphylococcus aureus Cowan I (SAC) at a concentration of 0.003% for 5 days, washed and further cultured in the absence of the antigen and SAC for an additional 5 or 6 days. Nonadherent cells of 'low-responders' responded to NIP-KLH plus SAC and produced anti-NIP antibody when they were cultured with not only NIP-KLH plus SAC but also with the culture supernatant obtained on phytohemagglutinin (PHA) stimulation of a mixture of PBMC from 2 donors. Furthermore, it was found that the PHA supernatants could be very effectively substituted for by human recombinant interleukin-2.

Antibody Formation↗
PubMed1986

Immunological effects of mouse ceruloplasmin.

Mouse ceruloplasmin, the level of which in serum increases on administration of antitumor polysaccharides, was shown to have enhancing effects on the antibody production of mouse spleen cells toward sheep red blood cells and restorative effects on the suppressed mixed lymphocyte reaction of spleen cells of tumor-bearing mice. The proliferation of interleukin-2 dependent cytotoxic T cells and the suppressed concanavalin A response of the tumor bearing mice spleen cells were also enhanced by this serum glycoprotein, weakly but reproducibly. Furthermore, this serum glycoprotein was found to enhance glucose consumption and interleukin-1 production and cytotoxic activities of mouse peritoneal macrophages. These results suggest that mouse ceruloplasmin plays some roles in the natural resistance surveillance against tumors.

Animals↗
PubMed1986

Identification of a mouse serum protein increased by administration of an antitumor polysaccharide, PSK, as a variant of mouse transferrin and some of its biological activities.

One of the so-called LC components, the content of which is increased in the serum of PSK (antitumor polysaccharide) treated mice, was purified by repeated ion-exchange column chromatography on DEAE-Sephadex A-50. The purified protein, designated as LC-2, was identified as a variant of mouse transferrin, which is a serum beta 1-globulin having an iron-binding capacity. The absorption spectrum and ultraviolet circular dichroism (CD) curve of LC-2 were identical with those of mouse transferrin. The molecular weight, isoelectric point and amino acid composition of LC-2 were in good agreement with the results obtained previously for mouse transferrin. However, the carbohydrate content of LC-2 was different from that of mouse transferrin. This protein restored the depressed spleen cell response of tumor-bearing mice to concanavalin A (Con A) and promoted the metabolism of proteose-peptone induced peritoneal macrophages obtained from tumor-bearing mice. Furthermore, it had weak but definite antitumor activity against Sarcoma 180 cells in vivo.

Animals↗
PubMed1986

Nerve regeneration through allogenic nerve grafts in mice.

The purpose of this study was to examine whether the basal laminae of Schwann cells in allografts could survive immunological rejection and serve as a conduit for regenerating nerves, as in the case of autogenic nerve grafts. Allografts of nerves were carried out using sciatic nerves of mice after the grafts had been repetitively frozen to kill their Schwann cells. Two mouse strains, C57BL/6N and C3H/HeN, were used, as they are known to differ in major histocompatibility complex. The mid-portion of the grafted nerve segments was examined by electron microscopy. In addition, the toe pad skin and lumbrical muscles were examined for determining whether regenerating nerves reinnervate sensory end organs and motor endplates. The process of nerve regeneration in the allograft was the same as that seen in the autograft. Cells in the graft disintegrated into cell debris and were phagocytized by macrophages, whereas the basal laminae of Schwann cells were not removed by macrophages, remaining in the form of tubes or scaffolds. Regenerating nerve fibers grew out through such basal lamina scaffolds, keeping in contact with the inner surface. Digital sensory corpuscles and motor endplates of the operated side were well reinnervated. The results indicate that the basal laminae of Schwann cells of the allograft may survive and serve as a conduit for regenerating axons in the same way as in the case of an autograft.

Animals↗
PubMed1986

Enrichment of antitumor effector cells that are effective in vivo from spleen cells of tumor-bearing mice through the use of Dolichos biflorus lectin.

Spleen cells of X5563 tumor-bearing mice were fractionated with Dolichos biflorus lectin (DBA) into DBA+ (agglutinable with DBA) and DBA- (nonagglutinable with DBA) fractions. The DBA- cells showed antitumor activity specific for X5563 cells in vivo when injected into mice together with X5563 cells (Winn assay) or injected i.p. into mice previously inoculated s.c. with X5563 cells (adoptive transfer) with simultaneous administration of interleukin-2. Both DBA+ and DBA- cells have the cell surface phenotype of Lyt-1-2+, but only DBA- cells exhibit antitumor activity in vivo, while DBA+ cells have stronger cytolytic activity against X5563 cells in vitro than DBA- cells. This cell separation method involving the use of DBA is simple and gives reproducible results and high yields of viable cells.

Animals↗
PubMed1986

Inhibition of experimental pulmonary metastasis of mouse colon adenocarcinoma 26 sublines by a sialic acid:nucleoside conjugate having sialyltransferase inhibiting activity.

The total and sialidase-releasable sialic acid contents of murine colon adenocarcinoma 26 sublines of high (NL-17) and low (NL-44) metastatic potential were found to be positively correlated with their ability to undergo metastasis. Furthermore, sialyltransferase activity of intact NL-17 cells was higher than that of NL-44 cells. These findings suggest that sialic acid on the cell surface may play a role in the metastasis of these cells. Therefore, the effect of a sialyltransferase inhibitor, 5-fluoro-2',3'-isopropylidene-5'-O-(4-N-acetyl-2,4-dideoxy-3,6,7,8-tetra -O -acetyl-1-methoxycarbonyl-D-glycero-alpha-D-galactooctapyranosyl)u ridine (Kl-8110), on the experimental lung metastasis of NL-17 or NL-44 cells was examined. Kl-8110 inhibited the transfer of sialic acid to its endogenous acceptor in NL-17 and NL-44 cells. NL-17 or NL-44 cells were injected into the tail veins of mice, and the metastasis-inhibiting activity of Kl-8110 was evaluated on the basis of both the lung weight and the number of pulmonary surface nodules about 3 wk after the tumor cell injection and of the survival ratio of mice inoculated with the tumor cells. Pretreatment of tumor cells with Kl-8110 together with i.v. injection of Kl-8110 caused significant inhibition of pulmonary metastasis of both NL-17 and NL-44 cells. Inhibition of metastasis and prolongation of survival were also observed on i.v. injection of Kl-8110 without pretreatment of the tumor cells with Kl-8110, but the degree of inhibition was lower than that in the case of the two treatments together. Kl-8110 itself had neither cytostatic nor cytotoxic effects on NL-17 and NL-44 but reduced the retention of tumor cells in the lungs. This antimetastatic effect of Kl-8110 may be due to modification of the tumor cell surface resulting from inhibition of sialyltransferase by Kl-8110. In addition, a beta-linked sialic acid:nucleoside conjugate (Kl-8111) and an equimolar mixture of Kl-8110 and Kl-8111 (Kl-414) also inhibited the metastatic ability of NL cells to the same extent as Kl-8110 did.

Adenocarcinoma↗
PubMed1985

Phosphorylated high mannose-type and hybrid-type oligosaccharide chains of human thyroglobulin isolated from malignant thyroid tissue.

Structures of anionic oligosaccharides released by endo-beta-N-acetylglucosaminidase H from human thyroglobulin (19 S) purified from normal and malignant (papillary carcinoma) thyroid tissues were studied by sequential exoglycosidase digestion and lectin affinity chromatography. It was revealed that sialylated hybrid-type oligosaccharides were present in thyroglobulin from normal thyroid tissue, whereas, in the case of thyroglobulin from malignant thyroid tissue, phosphorylated high-mannose type and hybrid-type oligosaccharides each containing one phosphate group in a diester linkage were present instead of sialylated oligosaccharides. The possible meaning of the phosphorylated oligosaccharides was discussed in relation to the low thyroglobulin content in malignant thyroid tissue.

Acetylglucosaminidase↗
PubMed1985

Partial purification and characterization of phospholipid N-methyltransferases from murine thymocyte microsomes.

Significant amounts of phospholipid N-methyltransferase activity in murine thymocytes were found to be distributed on the plasma membrane. The enzyme activity had an optimum pH of 9. The presence of divalent cations, Mg2+ (10 mM) or Ca2+ (1 mM), and EGTA separately in the assay had only a small effect on the enzyme activity. However, addition of both 10 mM Mg2+ and 1 mM Ca2+ increased the enzyme activity. The presence of two enzymes for each conversion of phosphatidylethanolamine (PE) to phosphatidylmonomethylethanolamine (PME) and PME to phosphatidylcholine (PC) was suggested by the result of the determination of the incorporated radioactivity into PME, phosphatidyldimethylethanolamine (PDE) and PC; the apparent Km values for S-adenosyl-L-methionine were 20 and 400-500 microM for the conversion of PE to PME and for the conversion of PME to PC they were 5 microM and 40 microM. S-Adenosyl-L-homocysteine (AdoHcy), a known inhibitor of enzymatic methylation, competitively inhibited [14C]methyl incorporation into total lipid. The apparent Ki value for AdoHcy was 44.7 microM. Two phospholipid N-methyltransferases were partially purified by extraction with sodium deoxycholate, gel filtration on Sephadex G-75, and affinity column chromatography on AdoHcy-Sepharose. One enzyme, mainly catalyzing the formation of PME, was purified approximately 1548-fold and the other catalyzing the formation of PDE and PC, was purified approximately 629- to 703-fold. However, the former still contained a little activity for PDE and PC formation and the latter contained a little activity for PME formation. In these partially purified phospholipid N-methyltransferase preparations, little contaminating protein O-carboxylmethyltransferase activity was observed; however, significant PC-phospholipase A2 activity was detected. This result may suggest that phospholipid N-methyltransferases associate with phospholipase A2 in the thymocyte plasma membrane.

Animals↗
PubMed1985

Mouse macrophage hybridomas secreting a cytotoxic factor and interleukin 1.

Stable mouse macrophage hybridomas were produced by somatic cell fusion between proteose peptone-elicited peritoneal macrophages and NS-1 myeloma cells. Three cloned hybrid cell lines, designated as N/P-5-3, -6-2, and -7-1, exhibited typical macrophage-like morphology. Moreover, their macrophage characteristics were confirmed by the manifestation of intracellular nonspecific esterase, the detection of Mac-1 antigens and Fc-receptors on the cell surface, and the demonstration of phagocytic and antigen-presenting activities. Furthermore, these cell lines, stimulated with LPS, secreted considerable amounts of a cytotoxic factor and interleukin 1. Cultured cells of various tumor cell lines were sensitive to the cytotoxic factor, but normal thymocytes, spleen cells, and liver cells were not killed by the factor.

Animals↗
PubMed1985

Purification and characterization of a cytotoxic factor produced by a mouse macrophage hybridoma.

A mouse macrophage cytotoxic factor was purified to homogeneity from the serum-free culture supernatant of a mouse macrophage hybridoma clone, N/P-7-1, stimulated with lipopolysaccharide by gel filtration, affinity chromatography, anion-exchange chromatography, and polyacrylamide gel electrophoresis. The purified material was judged to be homogeneous as to the criteria of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and has a relative molecular mass of 17,500, as determined by SDS-PAGE, or 55,000, as determined by gel filtration on columns of both Sephacryl S-200 and TSK G3000SW. It has an isoelectric point of 5.0, and is trypsin sensitive, stable at 56 degrees C and labile at pH less than 6. The cytotoxic activity of the purified factor could not be inhibited by various sugars and lectins. The production of the factor from N/P-7-1 triggered by macrophage-activating factor for cytotoxicity, but not by mouse recombinant gamma-interferon. The factor should be synthesized after lipopolysaccharide stimulation because treatment of N/P-7-1 cells with a metabolic inhibitor, emetine or actinomycin D, prevents the production.

Animals↗
PubMed1985

A hapten-induced conformational change accompanies the cryoprecipitation of an immunoglobulin.

By simultaneous spectroscopic measurements (absorbance, light scattering, fluorescence and circular dichroism) the temp-dependent behavior of a cryoglobulin, the mouse monoclonal immunoglobulin G to N-acetyllactosamine, has been observed. The results show that a hapten-induced conformational change in the structure of a cryoglobulin can accompany its intermolecular association. This association of the immunoglobulin increases after hapten saturation of its two antigen-combining sites.

Amino Sugars↗