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Biomedical subjects

M Sawada

Publications and source records attributed to M Sawada.

At least 199 records · Page 11Linked to original sources
PubMed1996

Stable expression of human CYP2E1 in Chinese hamster cells: high sensitivity to N,N-dimethylnitrosamine in cytotoxicity testing.

Involvement of human CYP2E1 expressed in genetically engineered cells in the metabolic activation of promutagens and procarcinogens was studied. An expression plasmid containing an insert of CYP2E1 cDNA and SR alpha promoter was constructed and transfected into the cultured cell line CR-119 which had previously been established by introducing a cDNA coding for NADPH-cytochrome P450 reductase. Among newly established cell lines, ER-181 showed the highest expression of CYP2E1 mRNA. Production of the CYP2E1 protein was confirmed by Western blot analysis using anti-rat CYP2E1 antibodies. Assay of 7-ethoxycoumarin O-deethylase activity demonstrated that ER-181 cells acquired the catalytic function of CYP2E1. ER-181 cells showed higher sensitivity to N,N-dimethylnitorosamine (DMN) in cytotoxicity assays as compared to parental CR-119 cells. Hypersensitivity to DMN of ER-181 cells was completely suppressed by 3-amino-1,2,4-triazole, a known inhibitor of CYP2E1. These results indicate that ER-181 cells which express human CYP2E1 are a useful tool to investigate toxicological functions of the cytochrome.

Animals↗
PubMed1996

Comparative analysis of cell surface antigens expressed by cell lines derived from human germ cell tumours.

The pattern of cell surface antigen expression of a set of cell lines derived from human germ cell tumours and corresponding to various cell phenotypes found within these tumours was studied using immunofluorescence. Twenty-two different antibodies were used. Many of these antibodies have been noted to recognise epitopes that are either preferentially expressed by embryonal carcinoma (EC) cells, or by more differentiated cell types. Using scatter plots and rank correlations, 6 groups of antibodies were distinguished with respect to their staining patterns on the cell lines tested. Several antibodies showed a specific staining pattern in relation to the differentiation state of the cells. Two groups of antibodies included those recognising high m.w. glycoproteins (antibodies TRA-1-60, TRA-1-81, GCTM2, 3-177, K4 and K21) and the ganglioseries glycolipid antigens SSEA-3 and -4 (antibodies MC631 and MC813-70). These antibodies mostly stained EC cells but not other cell types, confirming previously published data. However, one of these groups, comprising antibodies K4 and MC631, was more exclusively associated with the EC cell phenotype than was the other group. Antibodies recognising the liver isozyme of alkaline phosphatase (TRA-2-49 and TRA-2-54) also reacted strongly with most EC cell lines, although they reacted significantly with a number of other cell lines as well, whereas antibodies to the placental isozyme tended to react only weakly with EC cells. The antibodies recognising the ganglioseries glycolipids GD2 and GD3 (VIN2PB22 and VINIS56) preferentially stained cells with neuroectodermal characteristics. Other antibodies showed a heterogeneous staining pattern for the cell lines with different phenotypes. The data obtained from the cell lines were, in general, similar to data obtained from immunohistochemical studies on tissue sections of primary germ cell tumours of the adult testis, including carcinoma in situ.

Adult↗
PubMed1996

Nitric oxide donor sodium nitroprusside inhibits the acetylcholine-induced K+ current in identified Aplysia neurons.

The effects of bath-applied sodium nitroprusside (SNP), a nitric oxide (NO) donor, on an acetylcholine ACh-induced K+ current recorded from identified neurons (R9 and R10) of Aplysia kurodai were investigated with conventional voltage-clamp and pressure ejection techniques. Bath-applied SNP (25-50 microM) reduced the ACh-induced K+ current in the neurons without affecting the resting membrane conductance and holding current. The suppressing effects of SNP on the current were completely reversible. Intracellular injection of 1 mM guanosine 3',5'-cyclic monophosphate (cGMP) or bath-applied 50 microM 3-isobutyl-1-methylxanthine (IBMX), a nonspecific phosphodiesterase (PDE) inhibitor, also inhibited the ACh-induced current, thus mimicking the effect of the NO donor on the ACh-induced current. In contrast, pretreatment with methylene blue (10 microM), an inhibitor of guanylate cyclase, and hemoglobin (50 microM), a nitric oxide scavenger, decreased the SNP-induced inhibition of the ACh-induced current. These results suggest that SNP, a NO donor, inhibits the ACh-induced K+ current, and that the mechanism of NO inhibition of the ACh-induced current recorded from identified Aplysia neurons involves cGMP-dependent protein kinase.

Acetylcholine↗
PubMed1996

Selective induction of interleukin-6 in mouse microglia by granulocyte-macrophage colony-stimulating factor.

Astrocytes produce granulocyte/macrophage colony-stimulating factor (GM-CSF) and support the survival and proliferation of microglia. To study the functions of GM-CSF in the central nervous system (CNS), we examined the effects of GM-CSF on cytokine production by glial cells. GM-CSF induced interleukin-6 (IL-6) production by microglia, but not by astrocytes, in a dose-dependent manner as assessed by bioassay and the detection of IL-6 mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. GM-CSF did not induce tumor necrosis factor (TNF) alpha or IL-1 in microglia and astrocytes, whereas lipopolysaccharide induced all these cytokines. The induction of IL-6 by GM-CSF in microglia was completely inhibited by antibodies to GM-CSF. Neither IL-3 nor macrophage-CSF (M-CSF) induced IL-6 production in microglia. Given that IL-1 and TNF alpha, monokines derived from microglia, induce IL-6 production in astrocytes, but not in microglia, results indicate that astrocytes and microglia may mutually regulate IL-6 production by different cytokines.

Animals↗
PubMed1996

Expression pattern of messenger RNAs for prostanoid receptors in glial cell cultures.

Expression level of messenger RNAs (mRNAs) for prostanoid EP3, FP, and TP receptors was investigated in cultured rat astrocytes, oligodendrocytes, and microglia, as well as in meningeal fibroblasts, rat glioma C6 cells, rat pheochromocytoma PC12 cells, whole brain, and several peripheral tissues by reverse transcriptase-polymerase chain reaction. Cultured astrocytes and oligodendrocytes expressed mRNAs for 3 prostanoid receptors examined. In contrast, cultured microglia and pheochromocytoma PC12 cells expressed EP3 and TP receptor mRNAs, but not FP receptor mRNA. Glioma C6 cells expressed only TP receptor mRNA among 3 prostanoid receptors with the same expression level as that in astrocytes. Cultured meningeal fibroblasts expressed 3 receptor transcripts, and their expression levels were lower than those in astrocytes. Expression level of mRNA for each prostanoid receptor in cultured glial cells was higher than that in whole brain. These observations suggest that each prostanoid has its specific roles in each glial cell type of the brain.

Animals↗
PubMed1996

Occurrence of monocytoid B lymphocytes in lymph nodes of patients treated by chemotherapy.

Occurrence of monocytoi B lymphocytes (MBL) in the lymph nodes of patients receiving preoperative chemotherapy for cancer was examined and compared to lymph nodes in controls who had not received chemotherapy. Number of patients receiving and not receiving preoperative chemotherapy were 3 and 10 cases in ovarian cancer, 7 and 11 in testicular cancer, and 22 and 8 in lung cancer, respectively. Chemotherapeutic agents for ovarian, testicular, and lung cancer consisted of cisplatin, Adriamycin, and cyclophosphamide; cisplatin, vinblastine, and bleomycin; and cisplatin, vindesin, and mitomycin, respectively. MBL were defined morphologically as having abundant pale cytoplasm with distinct cell borders and small nucleus. Immunohistochemistry revealed a B-cell nature of these cells, i.e., CD20+ and/or MB-1+ together with negative reactivity for antibodies for T lymphocytes (CD43, CD45RO, OPD4) and macrophages (KP-1, PGM-1). Monocytoid cells in two cases showed a positive reactivity for CD43 together with CD20. The occurrence rate of MBL in patients with ovarian, lung, and testicular cancer receiving and not receiving chemotherapy was 67% (2/3) and 10% (1/10), 59% (13/22) and 75% (6/8), and 43% (3/7) and 9% (1/11), respectively. The occurrence rate in the total patients receiving chemotherapy (56%) was significantly higher than for those not receiving chemotherapy (28%) (P < 0.05). These findings suggest that chemotherapy-induced depressed immune function is causative for the occurrence of MBL in the lymph nodes. MBL might be found more frequently in nodes from patients who have received chemotherapy in certain settings.

Adult↗
PubMed1996

Methotrexate inhibits superoxide production and chemotaxis in neutrophils activated by granulocyte colony-stimulating factor.

Treatment of circulating human neutrophils with recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 30 min augmented superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in a dose dependent manner. When neutrophils were treated with 1 microM of methotrexate (MTX) for 60 min after incubation with rhG-CSF (10 ng/ml), the effects of rhG-CSF on superoxide generation and chemotaxis were inhibited by approximately 49 and 29%, respectively. Although inhibitory effects of MTX were also seen in neutrophils not pretreated with rhG-CSF, the degree of inhibition was much less. The addition of either hypoxanthine or guanosine at a concentration of 100 microM to the culture medium significantly attenuated the effects of MTX. However, in neutrophils obtained from a patient with Lesch-Nyhan syndrome, which lacked hypoxanthine-guanine phosphoribosyl transferase activity neither hypoxanthine nor guanosine had any rescue effect. These results suggest that MTX inhibits superoxide generation and chemotaxis in rhG-CSF-activated neutrophils, at least in part, by disturbing purine nucleotide biosynthesis.

Cells, Cultured↗
PubMed1996

Enhancement of phagocytosis by corticostatin I (CSI) in cultured mouse peritoneal macrophages.

Corticostatin I (CSI) is one of the corticostatic peptides which inhibit ACTH-stimulated steroidogenesis. To clarify the function of CSI on the immune system, the effect of CSI on phagocytosis by peritoneal macrophages was examined by means of flow cytofluorometry. In the presence of Ca2+ and Mg2+, CSI enhanced phagocytosis of latex beads in a dose-dependent manner. Unstimulated phagocytosis in physiological solution consisted of Ca2+ and Mg(2+)-dependent and -independent phagocytosis. Divalent cations-independent phagocytosis was sensitive to CSI. Present results suggest that the enhancement of phagocytosis by CSI may be one of the mechanisms modulating the immune response regarding infection and inflammation. Present study also showed that one of defensin HNP-1 enhanced phagocytosis.

Animals↗
PubMed1996

Enhancement of phagocytosis by calcitonin gene-related peptide (CGRP) in cultured mouse peritoneal macrophages.

Calcitonin gene-related peptide (CGRP) is widely distributed in sensory neurons and nerve fibers. To clarify the function of CGRP on the immune system, the effect of CGRP on phagocytosis by peritoneal macrophages was examined by means of flow cytofluorometry. CGRP enhanced phagocytosis of latex beads in a dose-dependent manner. Because the phosphodiesterase inhibitor 3-isobutyl, 1-methylxanthine (IBMX) enhanced the CGRP-induced enhancement of phagocytosis, the enhancement might be mediated by cAMP. In the presence of mannan, the phagocytosis was suppressed and the CGRP-induced enhancement was also blocked, suggesting that mannose receptors on macrophages were involved in mediating the phagocytosis of latex beads, and CGRP enhanced the mannose receptor-mediated phagocytosis. The present results indicate that CGRP can modulate the function of macrophages in nerve terminals of sensory neurons during the development and maintenance of inflammation.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Stimulation of bone formation in the expanding mid-palatal suture by transforming growth factor-beta 1 in the rat.

The most intense endogenous transforming growth factor (TGF)-beta 1 expression was detected in osteoblasts and fibroblasts in the mid-palatal suture 24 hours after the start of palatal expansion with an immunohistochemical technique. Based on these data, local effects of transforming growth factor-beta 1 (TGF-beta 1) in the expanding mid-palatal suture of the rat were examined. Single doses of human recombinant (rhu) TGF-beta 1 (40 and 200 ng, and 1 microgram) were injected into the expanding mid-palatal suture 24 hours after expansion started. Calcein was also injected immediately, and 6 and 12 days after expansion. The width of each calcein label was measured to evaluate bone formation along the suture with bone histomorphometry. In the experimental groups, bone formation during the 12-day expansion period was stimulated significantly (P < 0.05), in a dose-dependent manner, compared with that in the control group. Furthermore, bone formation during the later stage (6-12 days) of the 12-day expansion period, was still significantly higher than that in the control group. In addition, the amount of bone formation in response to a course of 3 injections of 200 ng rhu TGF-beta 1 on days 3, 6, and 9 was almost equal to that induced by a single injection of 200 ng rhu TGF-beta 1 on day 1. These results suggest that TGF-beta 1 may play an important role in bone formation at the active site of the suture in response to rapid palatal expansion and application of TGF-beta 1 during the early stages may induce rapid bone formation.

Acid Phosphatase↗
PubMed1996

Evaluation of the genotoxicity of stevioside and steviol using six in vitro and one in vivo mutagenicity assays.

Stevioside, a constituent of Stevia rebaudiana, is commonly used as a non-caloric sugar substitute in Japan. The genetic toxicities of stevioside and its aglycone, steviol, were examined with seven mutagenicity tests using bacteria (reverse mutation assay, forward mutation assay, umu test and rec assay), cultured mammalian cells (chromosomal aberration test and gene mutation assay) and mice (micronucleus test). Stevioside was not mutagenic in any of the assays examined. The aglycone, steviol, however, produced dose-related positive responses in some mutagenicity tests, i.e. the forward mutation assay using Salmonella typhimurium TM677, the chromosomal aberration test using Chinese hamster lung fibroblast cell line (CHL) and the gene mutation assay using CHL. Metabolic activation systems containing 9000 g supernatant fraction (S9) of liver homogenates prepared from polychlorinated biphenyl or phenobarbital plus 5,6-benzoflavone-pretreated rats were required for mutagenesis and clastogenesis. Steviol was weakly positive in the umu test using S.typhimurium TA1535/pSK1002 either with or without the metabolic activation system. Steviol, even in the presence of the S9 activation system, was negative in other assays, i.e. the reverse mutation assays using S.typhimurium TA97, TA98, TA100, TA102, TA104, TA1535, TA1537 and Escherichia coli WP2 uvrA/pKM101 and the rec-assay using Bacillus subtilis. Steviol was negative in the mouse micronucleus test. The genotoxic risk of steviol to humans is discussed.

Animals↗
PubMed1996

Bilateral tumor-like invasive xanthelasma palapebrarum in the superior palpebra.

We describe a very rare case of bilateral xanthelasma. Pathologically, xanthoma cells invaded the dermis, subcutaneous tissues, orbicularis muscle, orbital septum, orbital fat, and palpebral levator. Clinically, diplopia was present. Although considerable improvement was noted in appearance after surgical removal of as much of the tumors as possible, an increase in and a recurrence of the remaining tumors were observed at a later date following the operation.

Adult↗
PubMed1996

Effects of combination therapy with interferon and ofloxacin on chronic type C hepatitis: a pilot study.

Interferon is effective in only a limited number of patients with the 1b type of hepatitis C virus (HCV), indicating that a combination therapy with other antiviral drugs may be essential to obtain better results. In the present pilot study, the effects of a combination therapy with interferon (IFN) and an antibacterial drug, ofloxacin, were analysed. Ten patients with chronic type C hepatitis received the combination therapy (combination group). Six million units of natural IFN-alpha were administered daily for 3 weeks and then three times a week for 21 weeks. The combination therapy was initiated at the beginning of the eighth week of IFN treatment and 600 mg ofloxacin per day was administered for 12 weeks. As a control, changes in HCV-RNA were also analysed in patients who were treated with only IFN for the same period (IFN-alone group). In the combination group, serum transaminase levels and the titres of HCV decreased significantly with ofloxacin administration. Such changes were not observed in the IFN-alone group. The incidence of HCV-negativity at the end of ofloxacin administration of the combination group was significantly higher than in the IFN-alone group. The complete response rate was twice as high in the combination group as in the IFN-alone group. In two patients who did not respond well to the IFN-alone treatment, ofloxacin administration was commenced after the 24th week. Serum transaminase levels were normalized and HCV-RNA became negative in these two patients after the administration of ofloxacin. These results suggest that combination therapy with IFN and ofloxacin may be an effective treatment for chronic type C hepatitis.

Adult↗
PubMed1996

In-vivo distribution and erythrocyte binding characteristics of cyclosporin in renal transplant patients.

The pharmacokinetic parameters of cyclosporin, a potent immunosuppressive agent, show large intra- and inter-individual variability, possibly because of the different analytical methods used. A recently developed cyclosporin-specific radioimmunoassay has been used to study the in-vivo distribution and binding characteristics of cyclosporin in whole blood, plasma and erythrocytes of fifteen renal transplant patients. The profiles of cyclosporin concentration-time curves after an oral dose of cyclosporin had either one peak (ten patients, group A) or two (five patients, group B). Essentially no difference was observed between the two groups in the relationship between equilibrium cyclosporin concentrations in erythrocyte and plasma as a function of whole-blood concentration. The equilibrium in-vivo cyclosporin concentrations in erythrocyte and plasma were, however, markedly lower than those previously observed under in-vitro conditions. The ratio of cyclosporin concentration in erythrocytes (CE) to that in plasma (CP) changed with time, in inverse proportion to the change in cyclosporin concentration in blood, over the range 0.63-2.80 in individual patients with an average of 1.36 +/- 0.07 (mean +/- s.e.m.) for group A and 1.42 +/- 0.23 for group B. The apparent cyclosporin binding affinity (Kd) to erythrocytes under in-vivo conditions averaged 452.2 +/- 47.6 nM (543.5 +/- 57.2 ng mL-1) for group A and 419.4 +/- 41.2 nM (504.1 +/- 49.5 ng mL-1) for group B, whereas apparent cyclosporin binding capacity (Bmax) of the blood cell averaged 0.83 +/- 0.07 nmol mL-1 for group A and 0.78 +/- 0.07 nmol mL-1 for group B. Significantly reduced average Kd (262.7 +/- 40.2 nM or 315.8 +/- 48.9 ng mL-1, P < 0.01) and Bmax (0.56 +/- 0.08 nmol mL-1, P < 0.05) values were observed during the period after Tmax (4-12 h after the drug ingestion) in group A patients. Apparent Kd and Bmax, determined by a nonlinear regression technique, were 131.6 +/- 29.4 and 1088.0 +/- 114.7 nM (158.2 +/- 35.4 and 1307.8 +/- 137.9 ng mL-1) and 0.178 +/- 0.024 and 0.814 +/- 0.078 nmol mL-1, respectively, during the 4-12 h period in group A patients. These findings reveal distinct differences in in-vivo distribution of cyclosporin and the binding characteristics of the compound to erythrocytes from those previously observed under in-vitro conditions. The significantly lower Kd of cyclosporin binding to erythrocytes during the elimination phase suggests a potential effect of cyclosporin-containing erythrocytes or of cyclosporin contained in erythrocytes during cyclosporin treatment.

Adult↗
PubMed1996

Diabetic renal failure and serum accumulation of the creatinine oxidative metabolites creatol and methylguanidine.

Diabetic patients (n = 23) with chronic renal failure (CRF) accumulate the creatinine (Cr) oxidative metabolites creatol (CTL) and methylguanidine (MG; a uremic toxin) in their sera. Analysis of serum CTL, a key intermediate in mammalian Cr catabolism into MG, is shown to offer some useful diagnostic information on CRF, especially in the determination of an initial stage of pathological renal failure. The sera of all diabetic (n = 23) and nondiabetic (n = 20) patients with CRF (s-Cr > 1.25 mg/dl) contained s-CTL (> 2 micrograms/dl), whereas those from normal subjects (n = 18) and diabetic patients (n = 18) without CRF contained no detectable s-CTL. A similar accumulation of s-MG was observed, but only when s-Cr was higher than 2.0 mg/dl. Although each s-CTL (Y: microgram/dl, Y': mol/l) and s-MG level (Z: microgram/dl, Z': mol/l) is highly correlated with s-Cr (X: mg/dl, X': mol/l) in a normal equation, Y or Z = AX + B, an alternative correlation in a second-order equation, Y or Z = alpha X2 + beta X, could also fit well. Since the quadratic equation can be convertible to Y/X or Z/X = alpha X + beta [Y'/X' or Z'/X' = alpha' X+ beta'] and active oxygen species, especially hydroxyl radicals, convert Cr into CTL, Y/X, Y'/X', Z/X and Z'/X' values which might be a kind of indices for oxygen stress (oxidative stress) increased in proportion to the increased severity of CRF in such patients. Although its meaning and interpretation are still debatable, diabetic CRF patients had a significantly higher alpha' value (2.2) than that (0.89) of nondiabetic CRF patients. All serum values for Cr, CTL and MG were measured with HPLC.

Creatinine↗
PubMed1996

Intracellular regulation of progesterone secretion by the superoxide radical in the rat corpus luteum.

In this study we examined the prospect that the superoxide radical (SOR) is involved in the mechanism by which LH stimulates progesterone secretion in the rat corpus luteum (CL). Treatment of dispersed CL cells with low doses of LH or a SOR-generating system (xanthine-xanthine oxidase) resulted in a significant increase in progesterone release and SOR production. High doses of each treatment were inhibitory. SOR generation also decreased hCG binding. To determine whether SOR may be required for progesterone secretion, dispersed cells were electroporated with antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] and treated with either low (50 ng) stimulatory or high (20 micrograms) inhibitory doses of LH. At 50 ng LH, insertion of SOD or CAT dose-dependently inhibited progesterone secretion. However, at high doses of LH (20 micrograms), which are associated with high levels of SOR, electroporation of SOD or CAT produced the opposite response. This stimulatory response of SOD or CAT on progesterone release was also dose related. These results indicate that SOR may be involved in the mechanisms that stimulate as well as those that inhibit progesterone release. The effect on progesterone secretion appears to be dose related, with small increases associated with stimulation and high levels involved in inhibition of secretion.

Animals↗
PubMed1996

Cervical discitis associated with spinal epidural abscess caused by methicillin-resistant staphylococcus aureus.

A 53-year-old male developed fever, nuchalgia, shoulder pain, and sore throat after a partial sigmoidectomy. He suffered sudden onset of quadriplegia about 5 days later. Magnetic resonance (MR) imaging indicated the characteristic appearance of C5-6 intervertebral disc herniation. However, anterior discectomy showed that he had cervical discitis associated with spinal epidural abscess. Continuous pus drainage from the abscess and vigorous antibiotic therapy were undertaken after surgery. He improved and could walk with assistance. MR imaging with gadolinium can be useful in diagnosing pyogenic spinal infection (epidural abscess, osteomyelitis, and discitis), but care should be taken in MR image interpretation since spinal epidural abscess associated with discitis may mimic disc herniation. Axial MR images are important to distinguish this rare disease from other cervical disorders.

Abscess↗