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Biomedical subjects

T Miyazaki

Publications and source records attributed to T Miyazaki.

At least 487 records · Page 27Linked to original sources
PubMed1993

Saccharomyces cerevisiae can release hepatitis B virus surface antigen (HBsAg) particles into the medium by its secretory apparatus.

We constructed a plasmid that directs the synthesis and secretion of hepatitis B virus (HBV) surface antigen (HBsAg) particles by Saccharomyces cerevisiae. This plasmid contains a proteinase-resistant HBsAg M (M-P31c) gene fused at its 5'-terminus with a chicken-lysozyme signal peptide (C-SIG) gene, which is placed under the yeast GLD (glyceraldehyde-3-phosphate dehydrogenase gene) promoter. The products encoded by the "C-SIG+M-P31c" (LM-P31c) gene were synthesized and assembled themselves into HBsAg particles in yeast cells, and the particles were released into the medium along with poly-HSA (polymerized human serum albumin) binding activity. The HBsAg particles purified from the medium were very similar in density (1.19 g cm-3), size (19.2 +/- 0.8 nm in diameter) and shape (sphere) to human-plasma-derived HBsAg particles. When several sec (temperature-sensitive secretion-defective) mutants were used as host cells, the release of HBsAg particles into the medium was blocked at 37 degrees C but not at 25 degrees C, indicating that the HBsAg particles are exported through the normal yeast secretion pathway. To our knowledge, this is the first report that yeast cells are capable of secreting particles into the medium.

Amino Acid Sequence↗
PubMed1993

Sclerosing hepatocellular carcinoma: radiologic findings.

The radiologic findings of seven patients with sclerosing hepatocellular carcinoma (HCC), an unusual subtype of HCC, were evaluated. Computed tomography (CT) demonstrated a hypointense mass with marked delayed contrast enhancement. Although the tumor was well-defined, the tumor capsule was not seen. Focal atrophy was seen in four patients. Ultrasound (US) showed an isoechoic to hyperechoic mass without a rim. Angiography revealed prominent tumor vessels and prolonged stains in all cases. Arterial encasement was seen in four patients. On magnetic resonance (MR) imaging, all tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. On dynamic MR study, remarkable contrast enhancement, which continued to the delayed phase, seemed to be characteristic for sclerosing HCC. In the presence of liver tumors with homogeneous architecture, hypervascularity, prolonged enhancement, absence of tumor capsule, and focal atrophy in high-risk patients of HCC, sclerosing HCC should be considered.

Aged↗
PubMed1993

Liver parenchymal changes after transcatheter arterial embolization therapy for hepatoma: CT evaluation.

We retrospectively reviewed computed tomographic (CT) findings of 118 patients with hepatoma who received sequential follow-up CT after transcatheter arterial embolization (TAE). Thirty-five patients received TAE using Gelfoam particles with cisplatin, 37 patients using Gelfoam particles and iodized oil (Lipiodol) with cisplatin, and 46 patients using iodized oil with cisplatin. Liver atrophy was observed in 33 patients, lobarly or focally, depending on the embolized area. It was frequently associated with portal vein occlusion by the tumor, usage of iodized oil, and repeated embolization therapy. The lobar atrophy was seen in patients who had portal vein occlusion and/or received repeated embolization therapy. The focal atrophy was observed in patients who were administered iodized oil. Infarction developed in four patients who had a thrombus in the portal vein and received peripheral embolization therapy using iodized oil. We conclude that liver parenchymal changes occur frequently in patients who have portal vein occlusion and/or receive peripheral embolization using iodized oil.

Adult↗
PubMed1993

Monoclonal gammopathy (IgA: lambda) after autologous T-cell-depleted bone marrow transplantation in a patient with non-Hodgkin's lymphoma.

We report a case study of a patient suffering from T-lymphoblastic lymphoma, for whom autologous T-cell-depleted bone marrow transplantation was carried out. Low-dose cyclosporin A (CsA) was administered just after autologous bone marrow transplantation (ABMT) for induction of autologous graft-versus-host disease. Three months later, the lymphoma relapsed with marked monoclonal gammopathy of the immunoglobulin A type, which had not been seen before ABMT. It is suggested that the regrowth of the lymphoma cells was related to the maturation of B cells or the secretion of immunoglobulins from plasma cells, associated with some cytokines produced under the condition of an abnormal immunological circumstance after ABMT plus CsA.

Adult↗
PubMed1993

The role of Helicobacter pylori in peptic ulcer disease.

The linking of relapse of duodenal as well as gastric ulcers with Helicobacter pylori (H. pylori) has been a considerable advance in managing patients with peptic ulcer disease. However, pathogenetic role of H. pylori in peptic ulcer still remains unclear. The aim of this study was to assess the relationship between H. pylori infection and inflammatory cell infiltration in gastric mucosa in peptic ulcer disease. Sixty-four patients with endoscopically proven gastric ulcer and 26 patients with duodenal ulcer were evaluated by prospective study. Biopsy specimens were taken from the ulcer margin, corpus and antrum. Eradication of H. pylori was attempted by concomitant administration of amoxycillin 500 mg, metronidazole 250 mg and bismuth subnitrate 1 g twice daily for 2 weeks. H. pylori positive rates in clinical stages of gastric and duodenal ulcer showed almost the same values of more than 90%. The prevalence of H. pylori at the antrum and corpus was almost the same as that between gastric and duodenal ulcer patients, whereas a dramatic difference in the positive rates at the ulcer margin was observed between gastric and duodenal ulcer patients (83.9% and 35.0%, respectively). The prevalence of polymorphonuclear (PMN) cell infiltration at the ulcer margin was still high even at the scarring stage of gastric and duodenal ulcer with positive H. pylori, whereas a dramatic decrease of PMN cell infiltration was observed at the ulcer margin after successful eradication of H. pylori. These results suggest that H. pylori may play an important role in the pathogenesis of gastric and duodenal ulcer by inducing inflammatory cells such as PMN cells in gastric mocosa.

Amoxicillin↗
PubMed1993

Iron responsive element-binding protein (IRE-BP) in leukemic cells: analysis using enzyme-linked immunosorbent assay and semiquantitative polymerase chain reaction.

The level of iron responsive element-binding protein (IRE-BP) in leukemic cells, which is essential for iron homeostasis and plays an important role in cell metabolism and cell growth, was measured using an enzyme-linked immunosorbent assay (ELISA). Comparing the levels in different clinical stages, the levels in CML cells in the chronic phase (mean +/- S.E., 0.270 +/- 0.110 U/mg protein, n = 9) and those in AML cells (0.150 +/- 0.104 U/mg) protein, n = 21) were significantly lower than that in normal granulocytes (0.628 +/- 0.216 U/mg protein, n = 9, p < 0.001 vs CML and AML). Analysis of IRE-BP mRNA expression in leukemic cells using semiquantitative polymerase chain reaction showed suppressed expression of mRNA as compared to normal bone marrow cells. These observations suggest that there may be dysregulation of IRE-BP expression and production in leukemic cells.

Adult↗
PubMed1993

Sulfolipids and glycolipid sulfotransferase activities in human renal cell carcinoma cells.

A cell line (SMKT-R3) established from human renal cell carcinoma was characterized for the presence of sulfolipids and glycolipid sulfotransferases. Sulfolipids were found to constitute a large part of the acidic glycolipid fraction in SMKT-R3 cells. These findings were confirmed by metabolic labelling with 35S-sulfate. These sulfolipids were expressed at the surface of SMKT-R3 cells as ascertained by cytofluorometry using a monoclonal antibody directed to sulfolipids. Furthermore, markedly high activity levels of glycolipid sulfotransferases were observed in SMKT-R3 cells compared with other cell lines. These results suggest that the increased synthesis of sulfolipids in renal cell carcinoma tissue (Sakakibara et al., 1989. Cancer Res., 49, 335-339) is due to the elevation of the sulfotransferase activities of renal carcinoma cells themselves.

Carcinoma, Renal Cell↗
PubMed1993

The role of macrophages in antigen presentation and T cell tolerance.

Bone marrow derived cells (dendritic cells, macrophages and B cells) are involved in antigen presentation and T cell tolerance. However, the precise functions of each cell type remain unclear. To determine the role of macrophages we produced transgenic mice expressing I-E molecules only on macrophages, by introducing the hybrid gene containing the colony stimulating factor-1 (CSF-1) receptor promoter region and the structural gene encoding E alpha d into C57BL/6 mice. In these mice I-E restricted antigen presentation and T cell priming were impaired. With respect to T cell tolerance, I-E reactive T cells were anergized but not clonally deleted. These results clearly demonstrate that macrophages by themselves are defective in efficient I-E restricted antigen presentation, so that T cells exposed to antigens expressed on macrophages are led to anergy.

Animals↗
PubMed1993

Site dependence of methamphetamine concentrations in blood samples collected from cadavers of people who had been methamphetamine abusers.

Various blood samples were collected from heart cavities and blood vessels in eight autopsy cases of people who had been methamphetamine abusers. Methamphetamine and its metabolite, amphetamine, were determined by gas chromatography-mass spectrometry-selected ion monitoring. In four cases where left and right heart blood samples were collected, methamphetamine concentrations in the left heart blood samples were 1.9-2.6 times higher than those in the right heart blood samples. In three cases where pulmonary vein blood samples were collected, methamphetamine concentrations in the pulmonary vein blood samples were higher than those in other blood samples sites. To interpret the blood methamphetamine concentrations, site dependence should be taken into consideration.

Adult↗
PubMed1993

The mechanisms of aspirin-induced gastric mucosal injury.

We examined changes in intracellular pH with the fluorescent probe BCECF after treatment with aspirin (ASA) in gastric mucosal cells isolated from guinea pigs at various extracellular, pH levels. The cytotoxic activities of ASA and the intracellular trapping of ASA at various extracellular pH levels were also examined by colorimetric MTT assay and counting the influx of [14C](carboxyl-14C)-ASA. Under acid extracellular pH, ASA reduced intracellular pH in gastric mucosal cells and exhibited cytotoxicity. Intracellular trapping of ASA was also observed only under acidic extracellular conditions. The present study suggests that ASA causes gastric mucosal cell injury in vitro by reducing intracellular pH, resulting from intracellular trapping of ASA under acidic extracellular conditions.

Animals↗
PubMed1993

An evaluation of serodiagnostic tests in patients with candidemia: beta-glucan, mannan, candida antigen by Cand-Tec and D-arabinitol.

The serodiagnostic tests, beta-glucan, mannan, candida antigen by Cand-Tec, and D-arabinitol were evaluated in 10 patients with candidemia, 14 patients with suspected fungemia, and 10 healthy persons. By blood culture or lysis centrifugation, C. albicans was isolated from 5 patients, C. parapsilosis from 4, and C. tropicalis from 1 patient; no organisms were isolated from the 14 patients with suspected fungemia or the 10 healthy subjects. Beta-glucan was measured by the difference between two chromogenic limulus tests (Endotoxin test-D and Endospecy), which was more than 60 pg/ml in 7 of 9 (78%) candidemic patients and 1 of 12 (8%) patients with suspected fungemia. Mannan was positive in 6 of 10 (60%) candidemic patients and 1 of 13 (8%) patients with suspected fungemia. Both antigens were very sensitive and highly specific for candidemia. However, the Cand-Tec assay was less specific, because titers of more than 4 were observed in 5 of 14 (34%) patients with suspected fungemia. D-Arabinitol was the least sensitive, because a D-arabinitol/creatinine ratio greater than 2.0 mumol/mg was observed in only 2 of 7 (29%) candidemic patients. The titers of serodiagnostic tests decreased after successful treatment with an anti-fungal agent. Our results show that the combined use of the assays in necessary for accurate serological diagnosis of candidemia.

Adolescent↗
PubMed1993

Up-regulation of IL-6-receptors by IL-3 on a plasma cell leukaemia cell line which proliferates dependently on both IL-3 and IL-6.

In this report we show that IL-3 up-regulates the expression of IL-6-receptors on a plasma cell leukaemia cell line which proliferates in response to both IL-3 and IL-6. Quantitative binding studies and Scatchard analysis revealed that HSM-2.3 has a single class of high-affinity IL-6 binding sites (200/cell, dissociation constant at the equilibrium 1.43 x 10(-11) M). After stimulation with IL-3, HSM-2.3 has 1200 binding sites. IL-6 receptor mRNA expression was detected in HSM-2.3 only after stimulation with IL-3.

Base Sequence↗
PubMed1993

The IL-2 receptor complex: its structure, function, and target genes.

Proliferation of T lymphocytes is triggered by the interaction of IL-2 with its specific receptor following T lymphocyte activation. The receptor for IL-2 consists of at least three distinct subunits, the alpha chain (IL-2R alpha), the beta chain (IL-2R beta), and the gamma chain (IL-2R gamma). Although the role of IL-2R gamma in IL-2 signalling remains unclear, IL-2R beta is the subunit critical for receptor-mediated signalling. Because IL-2R beta lacks any apparent catalytic motifs, IL-2R beta may be physically or functionally coupled to other signalling molecules. Structure-function studies of IL-2R beta have revealed that at least two distinct cytoplasmic regions of IL-2R beta are involved in IL-2-induced cellular signalling. The "serine-rich" region of IL-2R beta was identified as a region critical for IL-2-induced mitotic signalling from experiments in which IL-2R beta mutant cDNAs lacking a particular cytoplasmic region or regions were expressed in an IL-3-dependent mouse pro-B cell line (BAF-B03). Meanwhile, another cytoplasmic region of IL-2R beta, the "acidic" region, is responsible for its physical association with an src-family protein tyrosine kinase (PTK), p56lck and is critical for activating the p56lck PTK following IL-2 stimulation. It is now evident that IL-2R beta is linked to at least two intracellular signalling pathways that mediate nuclear proto-oncogene induction. One pathway is linked to tyrosine phosphorylation events, mediated by a src-family protein tyrosine kinase (PTK), and that pathway leads to the induction of the c-fos, c-jun, and other genes of this family. Another pathway leads to c-myc gene induction by an as yet unknown mechanism. We discuss the complex signalling machinery that links the cell surface receptor to the nuclear events.

Animals↗
PubMed1993

Urinary trehalase activity in chronic glomerulonephritis.

To determine the diagnostic role of urinary trehalase in chronic glomerular disease, urinary trehalase activity and other urinary markers such as N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), alkaline phosphatase (ALP), gamma-glutamyltranspeptidase (gamma-GTP), lactate dehydrogenase (LDH), lysozyme and beta 2-microglobulin (BMG) were measured in patients with chronic glomerulonephritis, nephrotic syndrome and chronic renal failure. Urinary trehalase activity was significantly increased in chronic glomerular disease, especially nephrotic syndrome, as compared with that in the healthy subjects. The highest incidence of elevated excretion was observed for trehalase with 52% in chronic glomerular disease, followed by NAG. Urinary trehalase activities in the patients were significantly correlated with the urinary levels of protein, NAG and AAP and total score of tubular damage, but not correlated with urinary levels of BMG or lysozyme. In patients with chronic glomerulonephritis and nephrotic syndrome, there was no significant difference in urinary trehalase activities between with and without hematuria. These results indicate that in some patients with chronic glomerular disease, there is tubular involvement as substantiated by elevation of the other urinary enzymes and BMG. Urinary trehalase is elevated more often in these types of disease than other markers of tubular damage.

Acetylglucosaminidase↗
PubMed1993

Effect of hemodialysis on plasma levels of vasoactive peptides: endothelin, calcitonin gene-related peptide and human atrial natriuretic peptide.

To determine the role of vasoactive peptides such as endothelin (ET), calcitonin gene-related peptide (CGRP) and human atrial natriuretic peptide (hANP) in the regulation of blood pressure in uremic patients, and to determine the effect of various types of dialyzer membranes on hemodialysis (HD)-induced changes in plasma levels of such peptides, plasma ET, CGRP and hANP were measured in HD patients and patients on continuous ambulatory peritoneal dialysis (CAPD). Plasma levels of ET, CGRP, and hANP were significantly higher in HD and CAPD patients than in healthy subjects. There were no significant differences in plasma levels of ET, CGRP, and hANP between hypertensive and normotensive HD patients, and no significant correlation was observed between HD-induced changes in plasma levels and changes in blood pressure. Plasma levels of ET decreased when HD was performed using high-flux membranes, such as polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and cellulose triacetate (CTA), but did not decrease using a saponified cellulose (SC) membrane. Plasma levels of CGRP decreased in the case of PAN, but increased significantly with PMMA and showed no change with SC and CTA. Plasma levels of hANP decreased in all types of dialyzer membranes due to decreased secretion. These results indicate that the effect of HD on plasma levels of ET and CGRP, but not hANP, depends on the type of dialyzer membrane used.

Atrial Natriuretic Factor↗
PubMed1993

Suppressive effect of an oral sorbent on the accumulation of p-cresol in the serum of experimental uremic rats.

Serum p-cresol and phenol are markedly accumulated in uremic patients. To determine if an oral sorbent (AST-120) can decrease their serum concentrations in the uremic state, an oral sorbent was administered to experimental nephrectomized uremic rats. In uremic rats fed with oral sorbent, the serum concentration and the urinary excretion of p-cresol were markedly and significantly lower than those in control uremic rats, while those of phenol tended to be low in the uremic rats with oral sorbent as compared with control uremic rats. The concentrations of serum creatinine and blood urea nitrogen were significantly decreased in the uremic rats with oral sorbent. These findings demonstrate that oral sorbent adsorbs especially p-cresol in the intestine and prevents the accumulation of p-cresol in the serum of uremic rats.

Administration, Oral↗
PubMed1993

Immunopharmacological characterization of a highly branched fungal (1-->3)-beta-D-glucan, OL-2, isolated from Omphalia lapidescens.

The immunopharmacological activities of a fungal (1-->3)-beta-D-glucan, OL-2, isolated from "Leiwan" Omphalia lapidescens were examined. Intraperitoneal (i.p.) administration of OL-2 to ICR mice induced a significant number of peritoneal exudate cells (PEC) and white blood cells over the period of a few days. Spleen cell numbers were also increased by i.p. administration of OL-2 at about a week. These changes reverted to the normal level within a month. Responses of spleen cells and bone marrow cells (BM) to colony stimulating factors (CSF) were augmented by OL-2 administration assessed by cell proliferation assay. Sera from OL-2 administered mice contained an increased concentration of colony stimulating activity. Gene expressions of interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha in the spleen were also increased. These results suggested the activation of hematopoietic responses, and would well relate to the incremental increase in PEC, white blood cell and spleen cell numbers. OL-2 also increased the serum concentration of fibronectin and complement component C-3. However, OL-2 did not show adjuvant activity to SRBC and antitumor activity against the solid form of Sarcoma 180 by i.p. administration. Yet, OL-2 did not interfere with the antitumor activity of SSG against the same tumor system. These facts suggested that OL-2 could enhance nonspecific host defense mechanisms by enhancing hematopoietic responses, but would not enhance or inhibit the specific immunity mediated by lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗