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T Koga

Publications and source records attributed to T Koga.

At least 559 records · Page 31Linked to original sources
PubMed1987

Induction of delayed-type hypersensitivity by the T cell line specific to bacterial peptidoglycans.

A T cell line specific for the chemically well-defined peptidoglycan of bacterial cell wall, disaccharide tetrapeptide, was established from Lewis rats immunized with the antigen covalently linked to the autologous rat serum albumin. The antigen specificity was examined with various analogues or derivatives of the peptidoglycan. The cell line was reactive to analogues with the COOH-terminal D-amino acid, but least reactive to those with L-amino acid as COOH terminus. Transferring of the T cell line into X-irradiated normal Lewis rats induced delayed-type hypersensitivity in an antigen specific manner.

Animals↗
PubMed1987

Cyclosporin A enhances streptozocin-induced diabetes in CD-1 mice.

Cyclosporin A (CYA), when administered to CD-1 mice treated with a subdiabetogenic dose of Streptozocin (STZ), exacerbated the STZ-induced insulitis and elevated the plasma glucose levels, parallel to a reduction of the insulin content of the pancreas. The possible mechanisms of CYA-mediated aggravation of STZ-induced diabetes are discussed.

Animals↗
PubMed1987

Effect of guanosine triphosphate on the release and uptake of Ca2+ in saponin-permeabilized macrophages and the skeletal-muscle sarcoplasmic reticulum.

The effects of GTP, with or without polyethylene glycol (PEG), on the release and uptake of Ca2+ were examined by using saponin-treated macrophages and sarcoplasmic reticulum isolated from skeletal muscles. The application of GTP in concentrations in the range 0.1-10 microM induced a gradual, small but sustained release of Ca2+ from the saponin-treated macrophages. The addition of PEG to GTP markedly enhanced the GTP-mediated Ca2+ release. GTP at the same concentration ranges used for Ca2+ release decreased the amount of Ca2+ uptake, at a steady state, but stimulated the rate of Ca2+ accumulation in the presence of oxalate, the Ca2+-precipitating anion. The addition of PEG abolished the GTP-evoked stimulation of Ca2+ accumulation in the presence of oxalate. The stimulating effect on the rate of Ca2+ accumulation by GTP and its elimination by PEG were not due to changes in the permeability of oxalate by either GTP or PEG, or both. The Ca2+-releasing effect of GTP without PEG was enhanced by eliminating the uptake activity by decreasing the content of ATP. These results indicate that GTP has an inherent activity to release Ca2+ from non-mitochondrial intracellular stores of saponin-treated macrophages, and PEG enhances the GTP-mediated Ca2+ release, partly owing to its eliminating effect on GTP-stimulated Ca2+ uptake activity. These effects of GTP observed with saponin-permeabilized macrophages were not apparent in the isolated skeletal-muscle sarcoplasmic reticulum.

Animals↗
PubMed1987

The clinical usefulness of preoperative CEA determination in gastric cancer.

Between 1980 and 1984, preoperative serum carcinoembryonic antigen (CEA) was determined in 468 patients with gastric cancer to evaluate its clinical usefulness. The positive rate of preoperative CEA was 20.9 per cent in these 468 patients. A significantly higher CEA positive rate was obtained in those patients with liver metastasis (69.2 per cent), n3-4 (40.0 per cent), stage IV gastric cancer (37.0 per cent) and Pap, Tub1 histological type (26.3 per cent) (p less than 0.01). It is interesting that the positive rate of the 49 unresectable patients was 51.0 per cent, which was significantly higher than 17.4 per cent of the 419 resectable cases (p less than 0.01). CEA levels in 16 of the 39 patients with liver metastasis were more than 100 ng/ml. In contrast, serosal invasion and peritoneal metastasis were less correlated to the CEA positive rate. In the 419 resected cases, the 5 year survival rate in the higher CEA group of more than 50 ng/ml (35 cases) was 4.4 per cent, which was significantly lower than 64.0 per cent in the negative group (346 cases) (p less than 0.01). These results show that CEA determination in patients with gastric cancer is useful for the prediction of prognosis, as well as for a diagnostic tool to discover the presence of liver or lymph node metastasis.

Adult↗
PubMed1987

The usefulness of CEA as an indicator for early detection and a guide to the treatment of recurrent gastric cancer.

The usefulness of carcinoembryonic antigen (CEA) as an indicator for recurrence and a guide to the treatment was evaluated from a retrospective analysis of 88 patients with recurrent gastric cancer. Sixty-two of these patients (70.5 per cent), 25 of whom had a preoperative positive assay, and 37 a negative assay, had elevated levels of CEA after disease progression. Averaged CEA level in patients with liver metastasis was significantly higher (872 ng/ml) than in those with peritoneal metastasis (68 ng/ml), with lymph node metastasis (103 ng/ml) or with local metastasis (93 ng/ml) (p less than 0.01). An elevation of CEA was found prior to the clinical manifestation of recurrence, and the average lead time was 4 months. In 25 patients with a lead time of more than 4 months, survival time after CEA elevation was 13.3 months, which was longer than the 6.5 months of 28 patients with less than 4 months. Thirty-seven of the 88 patients were treated after recurrence. The average survival period after the detection of recurrence was 9.4 months in patients with surgical treatments followed by chemotherapy, 5.9 months in those with chemotherapy alone and 3.8 months in those with surgery alone. The average survival period of 26 patients with positive CEA assays in recurrence was 5.1 months longer than of patients with negative assays. This fact suggested that early detection of recurrence followed by various treatments, in the elevated CEA group, contributes to favorable results.

Adult↗
PubMed1987

Effect of guanosine triphosphate on the release of Ca2+ from intracellular store sites of saponin-treated human peripheral lymphocytes.

The effects of guanosine triphosphate (GTP) on the release and uptake of Ca2+ in nonmitochondrial intracellular store sites of human peripheral lymphocytes were examined. GTP in the presence of 3% polyethylene glycol released Ca2+ from the intracellular store sites of lymphocytes in a dose-dependent manner, and the maximal release was obtained at 10 microM GTP. GDP and 5'-GMP also enhanced the release of Ca2+. On the other hand, Ca2+ uptake in the presence of oxalate by saponin-treated lymphocytes was stimulated by GTP and this stimulation was abolished when polyethylene glycol was concomitantly present. The dose dependence of the stimulated Ca2+ uptake by GTP was much the same as that of the Ca2+ released by GTP. These results indicate that GTP has an inherent activity to release Ca2+ as well as to stimulate the uptake of Ca2+ in nonmitochondrial intracellular store sites of saponin-treated lymphocytes. The stimulatory effect of polyethylene glycol on GTP-mediated Ca2+ release may occur by inhibiting functions of the Ca2+ pump.

Biological Transport, Active↗
PubMed1987

Activation by calmodulin of inositol-1,4,5-trisphosphate 3-kinase in guinea pig peritoneal macrophages.

The activity of inositol-1,4,5-trisphosphate 3-kinase in the cytosol fraction of guinea pig macrophages was assayed with special reference to the dependence on the free Ca2+ concentration. The enzyme activity, as assessed by the production of inositol 1,3,4,5-tetrakisphosphate was reversibly activated by free Ca2+ concentrations ranging from 10(-7) to 10(-6)M. The calmodulin antagonists, W-7 and chlorpromazine, inhibited the Ca2+-activated enzyme activity in a dose-dependent fashion, thereby indicating that calmodulin may be involved in the activation by Ca2+. The content of calmodulin in the cytosol fraction (about 2.8 micrograms/mg of cytosol protein) was markedly reduced to less than 0.03 microgram/mg of proteins by subfractionation by ammonium sulfate, followed by an anion-exchange chromatography. The subfraction obtained by the chromatography showed no Ca2+ dependence in the enzyme activity, while an exogenous addition of calmodulin with 10(-6)M Ca2+ increased the enzyme activity. The enzyme activity was retained on a calmodulin-affinity column in the presence of Ca2+, and was eluted from the column by lowering the free Ca2+ concentration by adding ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid. These results clearly indicate that calmodulin activates the inositol-1,4,5-trisphosphate 3-kinase activity.

Animals↗
PubMed1987

A significant role of the macrophage accumulation induced by MCF in the protection of mice against Listeria monocytogenes in vivo.

Analysis was done on macrophage chemotactic factor (MCF) produced in the culture supernatant of spleen cells from mice immunized with Listeria monocytogenes. MCF was produced by Thy-1+, Lyt-1+ lymphocytes. MCF activity was resistant against pH 2 treatment and heating at 56 degrees C for 30 min, but was abolished by digestion with trypsin. G-100 gel filtration chromatography revealed that the approximate molecular weight of MCF was 15,000. MCF-rich fraction obtained by gel filtration chromatography showed neither MAF activity nor interferon activity. MCF activity in MCF-rich fraction was not affected by treatment with anti-rIFN-gamma antibody. An injection of MCF-rich fraction into the peritoneal cavity of mice induced a significant degree of accumulation of polymorphonuclear leukocytes (PMN) in a very short time after injection and macrophages thereafter. Resistance against listerial infection was augmented at the site where macrophage accumulation was provoked by the injection with MCF-rich fraction. It was shown that MCF plays an important role by itself in the protection against listerial infection by the accelerated accumulation of macrophages.

Animals↗
PubMed1987

Formalin fixed brains are useful for magnetic resonance imaging (MRI) study.

We carried out magnetic resonance imaging (MRI) studies on human brains which had been fixed in formalin solution for over 2 years and had been proven neuropathologically to be cases of multiple sclerosis (MS), progressive multifocal leukoencephalopathy (PML), and Balo's concentric sclerosis (Balo). Using spin echo (SE) and inversion recovery (IR) pulse sequences to detect demyelinated lesions in a living person with MS, the demyelinated lesions of the fixed brains in cases of MS, PML and Balo definitely re-appeared, although T1 and T2 in the gray and white matter were reduced following fixation. High signal areas on the SE images corresponded not only to the characteristic distribution of demyelinated lesions in the white matter but also to sparse myelin, gliosis and mild perivascular cuffing in the white matter around the demyelinated foci in cases of the fixed MS, PML and Balo brains. On the IR images, only MS plaques were evident. This MRI study of fixed brains proved useful to elucidate clinicopathological correlations.

Adolescent↗
PubMed1987

Serological relationships between serotype-III Streptococcus sanguis and Lancefield group-H streptococci.

Certain strains of Streptococcus sanguis and group-H streptococci have been shown to have similar physiological properties and serological specificities. Serological studies revealed that serotype-III S. sanguis shared a common antigen with the so-called "British" group-H streptococci, but not with the "American" group-H streptococci. Serotype-III antigen was extracted in cold 5% trichloroacetic acid from isolated cell walls of S. sanguis ATCC 10558, and purified chromatographically. The purified serotype-III antigen consisted of neutral and amino sugars and some phosphorus, and was negatively charged. Hapten inhibition of the quantitative precipitin reaction between serotype-III antigen and antiserum indicated the strong possibility of alpha-glucosidic linkages being an immunodeterminant of the antigen.

Antigens, Bacterial↗
PubMed1987

Pancreatic carcinoma associated with marked eosinophilia: a case report.

A case of pancreatic carcinoma associated with marked eosinophilia is reported. A 71-yr-old man was admitted to hospital because of melena and abdominal pain. The systematic examinations revealed pancreatic adenocarcinoma with multiple metastases (rectum, lung and brain). The leukocyte count was gradually increased and reached up to 81.7 X 10(9)/l, of which 54% consisted of eosinophils. Colony-stimulating factor (CSF) was detected both in the patient's serum and in the tumor extracts by a normal human bone marrow culture system. The colonies which were stimulated with patient's serum largely consisted of granulocyte, granulocyte/macrophage and eosinophil types. These results suggest that blood leukocytosis and eosinophilia were due to a high concentration of plasma CSF, which was probably produced by the tumor cells.

Adenocarcinoma↗
PubMed1987

Gamma interferon-mediated increase in the number of Ia-bearing macrophages during infection with Listeria monocytogenes.

The role of gamma interferon (IFN-gamma) in an increase in Ia-bearing macrophages during Listeria monocytogenes infection was studied. The peritoneal macrophages from L. monocytogenes-infected mice contained a high proportion of Ia. Intraperitoneal injection of the supernatant from a culture of spleen cells from L. monocytogenes-infected mice induced Ia-rich exudates in normal mice. The Ia-inducing activity in the culture supernatant was abrogated by the pretreatment of spleen cells with anti-Thy-1.2 antibody plus complement. Immunoadsorption of the culture supernatant with anti-recombinant IFN-gamma antibody and protein A-Sepharose CL-4B completely abrogated its Ia-inducing activity. These results suggested that an increase in Ia-bearing macrophages during L. monocytogenes infection was attributable to T-cell-derived IFN-gamma.

Animals↗
PubMed1987

Ultrastructure of extracellular polysaccharides produced by serotype c Streptococcus mutans.

The ultrastructure of extracellular polysaccharides produced in colonies by two clinical isolates and that of a nitrosoguanidine-induced mutant of serotype c Streptococcus mutans with different polysaccharide-synthesizing abilities were compared electron-microscopically. A large amount of polysaccharide was produced from sucrose by colonies of typical serotype c strain MT8148R and a clinical variant MT6801R with an enhanced fructan-synthesizing ability. Transmission electron-microscopy (TEM) revealed that the polysaccharides consisted of three structural components, i.e., globular, single-stranded filamentous, and double-stranded fibrillar structures. These structures were ascribed to production of fructan, water-soluble glucan, and water-insoluble glucan, respectively. On the other hand, two kinds of structures, a globular body and an amorphous substance, were observed by scanning electron-microscopy (SEM). The former was composed of fructan, while the latter contained a mixture of water-soluble and water-insoluble glucans which formed filamentous and double-stranded fibrillar structures under TEM. Very small quantities of polysaccharides were formed in colonies of mutant NG7183, which was derived from S. mutans MT6801R. This strain was found to possess low glucan- and no fructan-synthesizing abilities. The polysaccharides produced in colonies of mutant NG7183 were composed only of filamentous and double-stranded fibrils under TEM. A small amount of amorphous substance was observed by SEM in colonies of NG7183.

Dextranase↗