Biomedical subjects

R Nakagawa

Publications and source records attributed to R Nakagawa.

At least 19 recordsLinked to original sources

PubMed2003

Autoimmune hepatitis following allogeneic PBSCT from an HLA-matched sibling.

A 7-year-old boy with acute lymphoblastic leukemia (ALL) in second remission received an allogeneic PBSCT from his HLA-matched sister. Acute grade II graft-versus-host disease (GVHD) resolved with corticosteroids. Chronic GVHD in the skin and oral mucosa at around day 60 responded to corticosteroids and cyclosporin A. At 6 months after the transplant, he developed hepatic dysfunction with elevated serum transaminases and gamma-globulin. Liver biopsy revealed chronic inflammation with lymphocytes and plasma cells in portal areas without destruction of bile ducts, suggesting autoimmune hepatitis. While rare, autoimmune hepatitis should be considered a potential long-term complication in patients with hepatic dysfunction in the late post-transplant phase.

Biopsy↗

PubMed2002

An in vitro evaluation of four materials as barriers to coronal microleakage in root-filled teeth.

AIM: To assess the ability of IRM, Coltosol, Vidrion R and Scotch Bond to seal the pulp chamber following root-canal treatment. METHODOLOGY: Root-canal treatment was completed on 100 extracted human mandibular molars. The teeth were divided into five groups of 20 teeth each, one group for each barrier material and one control group without barrier material. Two millimetres of the restorative material was placed on the pulp chamber floor. The teeth were thermocycled and evaluated for microleakage using India ink. Specimens were cleared and measurements made to the maximum point of dye penetration. The mean dye penetration for each group was compared by the Kruskal-Wallis test. RESULTS: All groups showed dye penetration. Coltosol and IRM sealed significantly better than the other groups, preventing the coronal leakage in 84% and 75% of the specimens, respectively. Scotch Bond exhibited the highest leakage (54% of specimens with dye penetration), which did not differ significantly from the positive control group (62% with dye penetration). CONCLUSIONS: None of the materials were able to prevent microleakage in all specimens. Vidrion R and Scotch Bond demonstrated the poorest results when used as barriers to coronal microleakage, whilst IRM and Coltosol were significantly better in preventing microleakage.

Carbon↗

PubMed2001

Mechanisms of the antimetastatic effect in the liver and of the hepatocyte injury induced by alpha-galactosylceramide in mice.

The role of mouse liver NK1.1 Ag(+) T (NKT) cells in the antitumor effect of alpha-galactosylceramide (alpha-GalCer) has been unclear. We now show that, whereas alpha-GalCer increased the serum IFN-gamma concentration and alanine aminotransferase activity in NK cell-depleted C57BL/6 (B6) mice and B6-beige/beige mice similarly to its effects in control B6 mice, its enhancement of the antitumor cytotoxicity of liver mononuclear cells (MNCs) was abrogated. Depletion of both NK and NKT cells in B6 mice reduced all these effects of alpha-GALCER: Injection of Abs to IFN-gamma also inhibited the alpha-GalCer-induced increase in antitumor cytotoxicity of MNCS: alpha-GalCer induced the expression of Fas ligand on NKT cells in the liver of B6 mice. Whereas alpha-GalCer did not increase serum alanine aminotransferase activity in B6-lpr/lpr mice and B6-gld/gld mice, it increased the antitumor cytotoxicity of liver MNCS: The alpha-GalCer-induced increase in survival rate apparent in B6 mice injected intrasplenically with B16 tumor cells was abrogated in beige/beige mice, NK cell-depleted B6 mice, and B6 mice treated with Abs to IFN-gamma. Depletion of CD8(+) T cells did not affect the alpha-GalCer-induced antitumor cytotoxicity of liver MNCs but reduced the effect of alpha-GalCer on the survival of B6 mice. Thus, IFN-gamma produced by alpha-GalCer-activated NKT cells increases both the innate antitumor cytotoxicity of NK cells and the adaptive antitumor response of CD8(+) T cells, with consequent inhibition of tumor metastasis to the liver. Moreover, NKT cells mediate alpha-GalCer-induced hepatocyte injury through Fas-Fas ligand signaling.

Alanine Transaminase↗

PubMed2001

GATA DNA-binding protein expressed in mouse I-10 Leydig testicular tumor cells.

A nuclear extract of the mouse I-10 Leydig tumor cell line was analyzed by gel mobility shift assay with a combination of antibodies for various mammalian GATA proteins. Antibodies for GATA-4 caused a super-shift of the DNA-protein complex, which is formed through GATA-4 binding to an oligonucleotide with a typical GATA motif, while ones for GATA-1, GATA-2, GATA-3, and GATA-6 did not. These results indicated that I-10 cells express GATA-4 protein. Western blotting analysis of cellular proteins also demonstrated the presence of GATA-4 protein, the size of which corresponds to that of the rat orthologous protein transiently expressed in Cos-1 cells. A significant level of GATA-4 expression in I-10 cells would be advantageous for studying the roles of this protein, especially in view of gonadal function. We further examined the binding site preference of GATA-4 expressed in I-10 cells. GATA-4 showed broad sequence specificity similar to GATA-6, the order of binding core site preference being GATA > GATT > GATC, and adenine was favored on both sides of the core for strong binding. Thus the conserved zinc finger domain of GATA proteins is suggested to contribute to the binding sequence preference. GATA-4 expressed in I-10 cells was not susceptible to proteolysis coupled with cAMP signaling.

Animals↗

PubMed2001

Identification of breast cancer resistant protein/mitoxantrone resistance/placenta-specific, ATP-binding cassette transporter as a transporter of NB-506 and J-107088, topoisomerase I inhibitors with an indolocarbazole structure.

The antitumor drugs NB-506 and J-107088 are potent topoisomerase I inhibitors with an indolocarbazole structure. To clarify the factors involved in resistance to these drugs, we established two NB-506-resistant mouse fibroblast cell lines (LY/NR1 and LY/NR2), a human colon carcinoma cell line (HCT116/NR1), and a lung cancer cell line (PC13/NR1). These cell lines were highly resistant to NB-506 and J-107088, and LY/NR2 cells showed markedly reduced accumulation and strong efflux of NB-506, suggesting activation of a drug efflux pump in the resistant cells. To identify the molecules responsible for efflux of NB-506, we compared the gene expressions of the mouse resistant LY/NR1 cells, LY/NR2 cells, and their parental cells by oligonucleotide microarray. Of 34,020 genes analyzed, we found that an ATP-binding cassette transporter BCRP/MXR/ABCP (BCRP) gene showed the highest increase in the expression, 31-fold higher in the LY/NR2-resistant cells than in their parental cells. The selective overexpression of this gene was also detected in the two human resistant cell lines, suggesting the involvement of breast cancer resistant protein (BCRP) in the resistance and efflux of these drugs. Finally, a PC-13 cell line transfected with BCRP expression vector displayed 22- and 17-fold resistance to NB-506 and J-107088 and enhanced efflux activity of J-107088. However, the transfectants were not resistant to mitoxantrone or topotecan, the drugs previously thought to be the substrates of BCRP. Thus, our study presents a novel mechanism of drug resistance mediated by BCRP.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed2001

Signal transducer and activator of transcription (STAT)-induced STAT inhibitor 1 (SSI-1)/suppressor of cytokine signaling 1 (SOCS1) inhibits insulin signal transduction pathway through modulating insulin receptor substrate 1 (IRS-1) phosphorylation.

Signal transducer and activator of transcription (STAT)-induced STAT inhibitor 1 (SSI-1) is known to function as a negative feedback regulator of cytokine signaling, but it is unclear whether it is involved in other biological events. Here, we show that SSI-1 participates and plays an important role in the insulin signal transduction pathway. SSI-1-deficient mice showed a significantly low level of blood sugar. While the forced expression of SSI-1 reduced the phosphorylation level of insulin receptor substrate 1 (IRS-1), SSI-1 deficiency resulted in sustained phosphorylation of IRS-1 in response to insulin.Furthermore, SSI-1 achieves this inhibition both by binding directly to IRS-1 and by suppressing Janus kinases. These findings suggest that SSI-1 acts as a negative feedback factor also in the insulin signal transduction pathway through the suppression of IRS-1 phosphorylation.

Animals↗

PubMed2001

Update of daily intake of PCDDs, PCDFs, and dioxin-like PCBs from food in Japan.

Total diet study (TDS) samples of 14 food groups from 16 locations in Japan, collected in 1999 and 2000, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) to estimate the update of daily intake of these contaminants from food. The mean daily intake of toxic equivalency (TEQ) for an adult weighing 50 kg, calculated at non-detected isomer concentrations equal to zero (ND = 0), was estimated to be 2.25 pg TEQ/kg b.w./day. When non-detected isomer concentrations are assumed to be equal to half of the limits of detection (ND = 1/2 LOD), the mean daily intake was estimated to be 3.22 pg TEQ/kg b.w./day. These values were below the tolerable daily intake (TDI) of 4 pg TEQ/kg b.w. for PCDD/Fs and dioxin-like PCBs set in Japan. In both the estimates, the mean daily intakes were highest from fish and shellfish (76.9% at ND = 0 and 53.9% at ND = 1/2 LOD of the total TEQs), followed by those from meat and eggs (15.5% at ND = 0 and 11.7% at ND = 1/2 LOD of the total TEQs). Congener specific data revealed that these total TEQ levels were dominated by 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3',4,4',5-PeCB in each case (71.7% at ND = 0 and 63.1% at ND = 1/2 LOD of the total TEQs). The dioxin-like PCBs (non-ortho and mono-ortho PCBs) accounted for about 50% of these total TEQs. These data will be very useful in the risk assessment of PCDD/Fs and dioxin-like PCBs from food in Japan.

Adult↗

PubMed2001

SOCS-1/SSI-1-deficient NKT cells participate in severe hepatitis through dysregulated cross-talk inhibition of IFN-gamma and IL-4 signaling in vivo.

Suppressor of cytokine signaling-1 (SOCS-1), also known as STAT-induced STAT inhibitor-1 (SSI-1), is a negative feedback molecule for cytokine signaling, and its in vivo deletion induces fulminant hepatitis. However, elimination of the STAT1 or STAT6 gene or deletion of NKT cells substantially prevented severe hepatitis in SOCS-1-deficient mice, while administration of IFN-gamma and IL-4 accelerated its development. SOCS-1 deficiency not only sustained IFN-gamma/IL-4 signaling but also eliminated the cross-inhibitory action of IFN-gamma on IL-4 signaling. These results suggest that SOCS-1 deficiency-induced persistent activation of STAT1 and STAT6, which would be inhibited by SOCS-1 under normal conditions, may induce abnormal activation of NKT cells, thus leading to lethal pathological changes in SOCS-1-deficient mice.

Animals↗

PubMed2001

Intense immunosuppression followed by purified blood CD34+ cell autografting in a patient with refractory juvenile rheumatoid arthritis.

A 15-year-old boy with refractory juvenile rheumatoid arthritis (JRA) underwent intense immunosuppressive therapy followed by purified blood CD34+ cell autografting. He had been taking prednisolone (PDN) daily or every other day combined with methotrexate once a week to control the disease for 7 years. He suffered from psychological complications and a very short stature due to the adverse effects of these drugs. CD34+ cells were purified in bulk from G-CSF-mobilized PBSC using an Isolex 300. After the administration of cyclophosphamide (200 mg/kg) and anti-lymphocyte globulin (45 mg/kg), 3.6 x 10(6)/kg purified CD34+ cells were infused. His post-transplant course was uneventful except for herpes-zoster infection. He is now more than 1 year post transplant and has not taken any immunosuppressive medication. His rate of growth has increased (>10 cm/year) due to the effects of the cessation of PDN and the administration of recombinant human growth hormone (rGH), in contrast to the gain of 2 cm in the preceding 3 years with rGH treatment. Although the durability of this remission is unknown, intense immunosuppressive therapy followed by purified blood CD34+ cell autografting might be acceptable for adolescent patients with refractory JRA to achieve a drug-free period for physical and psychological maturation.

Adolescent↗

PubMed2001

Decrease in circulating hematopoietic progenitor cells by trapping in the pulmonary circulation.

BACKGROUND: When stem-cell grafts are infused into the venous circulation and stem/progenitor cells egress from BM, pulmonary capillary beds are the first microcirculation site that they encounter. This provides the potential for circulating progenitor cells to be trapped in the pulmonary circulation. METHODS: We compared the number of progenitor cells [CD34(+) cells, colony-forming unit-granulocyte-macrophage (CFU-GM), CD34(+) CD41(+) cells and CFU-megakaryocyte (CFU-meg)] and their expression of cell-adhesion molecules (CAM) in samples taken simultaneously from radial arteries and central veins of 21 patients following PBSC mobilization. RESULTS: The mean (+/- SD) frequency of progenitor cells in the radial arteries was reduced to 79% +/- 25% for CD34(+) cells, 73% +/- 27% for CFU-GM, 77% +/- 25% for CD34(+) CD41(+) cells and 70% +/- 29% for CFU-meg of the number in the central veins. This suggests that some progenitor cells might be trapped in the lung. No association between progenitor-cell expression of CAM and pulmonary trapping was observed. DISCUSSION: Our data demonstrate pulmonary trapping of PBSC during mobilization, suggesting a potential inhibitory effect on PBSC harvest and medullary trafficking following graft infusion. However, the impact associated with pulmonary PBSC trapping may be negligible in the clinical setting if sufficient cells are infused.

Antigens, CD34↗

PubMed2001

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in green leafy vegetable 'Komatsuna'.

The effects of ordinary household cooking processes on concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) were investigated in 'komatsuna', a green leafy vegetable popular in Japan. The concentrations of dioxins were compared using isomer-specific analyses of both uncooked and cooked edible parts of the plant. The mean total 2,3,7,8-chlorine substituted PCDD and PCDF concentrations were reduced from 46.53 pg/g and 0.714 pg/g to 8.301 pg/g and 0.210 pg/g by washing with tap water, and further reduced to 6.054 pg/g and 0.148 pg/g by subsequent boiling, respectively. The cooking processes markedly decreased the concentrations of PCDD/Fs, while having little effect on those of dioxin-like PCBs. The mean total concentration as 2,3,7,8-tetraCDD equivalents (TEQ) was reduced from 0.058 pgTEQ/g to 0.026 pgTEQ/g by washing with tap water and further reduced to 0.019 pgTEQ/g by subsequent boiling. These results suggest that ordinary cooking processes provide a means of reducing the level of dioxins in green leafy vegetables.

Benzofurans↗

PubMed2001

[Follow-up survey of dioxins in the blood of Yusho patients (in 1998-1999)].

Follow-up survey of the blood concentration of PCDDs, PCDFs and non-ortho-chlorine substituted PCBs in Yusho patients is very important for their health control. We determined the blood concentration of these dioxin isomers in 119 blood samples collected in 1998 and 1999 using by a high-resolution gas chromatograph/high-resolution mass spectrometry (HRGC/HRMS). Thirty years had passed since the Yusho occurrence, and the total blood concentrations of PCDFs in the blood of Yusho patients were still as high as ever, except the patients with the PCB pattern C. Among the different groups of PCB patterns, the concentration of 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF and 1,2,3,6,7,8-HxCDF showed significant differences, excluding the group BC because of the small number of cases. The findings indicate that these isomers are not decomposed in human body since they had highly contaminated the causal rice oil at the onset. In typical Yusho patients (Group A of PCB pattern), the mean TEQ concentrations of PCDDs, PCDFs and non-ortho-chlorine substituted PCBs in the blood collected in 1998 were 21, 206, and 14 pg-TEQ/g lipid, respectively, and in 1999, 30, 308 and 14 pg-TEQ/g lipid, respectively. The toxic contribution rate of PCDFs TEQ was still at high levels for total TEQ in both years. The patients of the group C, however, the mean blood levels of the dioxins TEQ in 1998 and 1999 did not differ from those of the normal controls determined in 1996 although some patients in this group showed a high toxic contribution rate of PCDFs TEQ for total TEQ. We will try the PCB isomer specific analysis of the Yusho patients blood, and will investigate the difference from normal controls blood.

Benzofurans↗

PubMed2000

Defective thymocyte development and perturbed homeostasis of T cells in STAT-induced STAT inhibitor-1/suppressors of cytokine signaling-1 transgenic mice.

Previous experiments have shown that STAT-induced STAT inhibitor-1 (SSI-1; also named suppressors of cytokine signaling-1 (SOCS-1) or Janus kinase binding protein) is predominantly expressed in lymphoid organs and functions in vitro as a negative regulator of cytokine signaling. To determine the function of SOCS-1 in vivo, we generated SSI-1 transgenic mice using the lck proximal promoter that drives transgene expression in T cell lineage. In thymocytes expressing SSI-1 transgene, tyrosine phosphorylation of STATs in response to cytokines such as IFN-gamma, IL-6, and IL-7 was inhibited, suggesting that SSI-1 suppresses cytokine signaling in primary lymphocytes. In addition, lck-SSI-1 transgenic mice showed a reduction in the number of thymocytes as a result of the developmental blocking during triple-negative stage. They also exhibited a relative increase in the percentage of CD4+ T cells, a reduction in the number of gammadelta T cells, as well as the spontaneous activation and increased apoptosis of peripheral T cells. Thus, enforced expression of SSI-1 disturbs the development of thymocytes and the homeostasis of peripheral T cells. All these features of lck-SSI-1 transgenic mice strikingly resemble the phenotype of mice lacking common gamma-chain or Janus kinase-3, suggesting that transgene-derived SSI-1 inhibits the functions of common gamma-chain-using cytokines. Taken together, these results suggest that SSI-1 can also inhibit a wide variety of cytokines in vivo.

Animals↗

PubMed2000

Signals transducers and activators of transcription (STAT)-induced STAT inhibitor-1 (SSI-1)/suppressor of cytokine signaling-1 (SOCS-1) suppresses tumor necrosis factor alpha-induced cell death in fibroblasts.

Signal transducers and activators of transcription (STAT)-induced STAT inhibitor-1 [SSI-1; also known as suppressor of cytokine signaling-1 (SOCS-1)] was identified as a negative feedback regulator of Janus kinase-STAT signaling. We previously generated mice lacking the SSI-1 gene (SSI-1 -/-) and showed that thymocytes and splenocytes in SSI-1 -/- mice underwent accelerated apoptosis. In this paper, we show that murine embryonic fibroblasts lacking the SSI-1 gene are more sensitive than their littermate controls to tumor necrosis factor-alpha (TNF-alpha)-induced cell death. In addition, L929 cells forced to express SSI-1 (L929/SSI-1), but not SSI-3 or SOCS-5, are resistant to TNF-alpha-induced cell death. Furthermore L929/SSI-1 cells treated with TNF-alpha sustain the activation of p38 mitogen-activated protein (MAP) kinase. In contrast, SSI-1 -/- murine embryonic fibroblasts treated with TNF-alpha show hardly any activation of p38 MAP kinase. These findings suggest that SSI-1 suppresses TNF-alpha-induced cell death, which is mediated by p38 MAP kinase signaling.

Androstadienes↗

PubMed2000

Synthesis and antiviral activity of novel anti-VZV 5-substituted uracil nucleosides with a cyclopropane sugar moiety.

A series of 5-substituted uracil nucleoside derivatives with a 1(1'S, 2'R)-[1',2'-bis(hydroxymethyl)cyclopropyl]methyl group as an acyclosugar moiety were synthesized and evaluated for their anti-herpetic activities. Among the compounds synthesized, (E)-5-halovinyluracil derivatives showed superior anti-varicella zoster virus (VZV) activity over acyclovir (ACV) but were less potent than ACV against herpes symplex virus type-1 (HSV-1). IC(50) values for the VZV Kawaguchi strain were 0.027 for Br, 0.070 for Cl, and 0.054 microg/mL for I derivatives and 3.4 microg/mL for ACV. The most potent compound, (1'S,2'R)-5-[(E)-2-bromoethenyl]-1-[[1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]-2,4-(1H, 3H)-pyrimidinedione (3a), was 40-60-fold more potent than ACV against clinical isolates of VZV. It showed good oral bioavailability in rats (68.5%) and, unlike (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil (BVaraU), did not result in the release of (E)-5-(2-bromovinyl)uracil (BVU), a potent dihydropyrimidine dehydrogenase inhibitor, in plasma after oral administration.

Animals↗

PubMed2000

Enantioselective Reactions of Configurationally Unstable alpha-Thiobenzyllithium Compounds.

Too unstable for asymmetric deprotonation, alpha-sulfenyl carbanions can undergo asymmetric substitution reactions with high stereoselectivity [Eq. (1)]. The key to the asymmetric induction is the dynamic kinetic resolution of the complex formed between the organolithium compound and a chiral ligand, the most effective of which were bisoxazoline derivatives.

Journal Article↗

PubMed2000

HLA-mismatched CD34-selected stem cell transplant complicated by HHV-6 reactivation in the central nervous system.

We report here a patient who suffered from PCR- confirmed human herpesvirus type 6 (HHV-6) meningoencephalitis after allogeneic purified CD34+ cell transplantation from his HLA-mismatched sibling donor, even though he had been on intense prophylaxis with i.v. ganciclovir (GCV), acyclovir (ACV) and gamma-globulin containing a specific antibody against HHV-6. Serological evaluation disclosed that both the donor and recipient had IgG antibody against HHV-6 before transplantation. His blood WBC count started to transiently increase on day 10, and all blood components had decreased by day 20. He then developed a severe headache and high blood pressure, and sporadic abnormal neurological findings including nystagmus and delirium. An analysis of cerebrospinal fluid (CSF) revealed 8 cells/microl, a glucose level of 130 mg/dl and a protein level of 201 mg/dl (normal, 50 mg/dl) on day 26. At the time, HHV-6 was detected only in CSF by a PCR-based method and he was diagnosed as having meningoencephalitis due to the local reactivation of HHV-6. Although he failed to respond to high-dose therapy with ACV (60 mg/kg/day) and gamma-globulin, the DNA of this virus disappeared from the CNS upon treatment with GCV (30 mg/kg/day) combined with the intraventricular infusion of alpha-interferon. His clinical course was further complicated with meningoencephalitis due to staphylococcus epidermidis, and he died of tentorial herniation on day 79 without the recovery of blood components. This experience may indicate that intense prophylaxis to prevent reactivation of HHV-6 in the CNS is essential for the management of such profoundly immunosuppressed patients.

Acyclovir↗

PubMed2000

Decrease of CD56(+)T cells and natural killer cells in cirrhotic livers with hepatitis C may be involved in their susceptibility to hepatocellular carcinoma.

CD56(+)T cells and CD56(+)natural killer (NK) cells are abundant in the human liver. The aim of this study was the further characterization of these cells in the liver with or without hepatitis C virus (HCV) infection. Liver mononuclear cells (MNC) were isolated from liver specimens obtained from the patients during abdominal surgery. In addition to a flow cytometric analysis, liver MNC and PBMC were cultured with the immobilized anti-CD3 Ab, IL-2, or a combination of IL-2 and IL-12 and their IFN-gamma production and the antitumor cytotoxicity were assessed. The liver MNC of HCV (-) patients contained 20% CD56(+)T cells whereas the same proportions decreased to 11% in chronic hepatitis livers and to 5% in cirrhotic livers. The proportion of NK cells also decreased in the cirrhotic livers. On the other hand, the populations of these cells in PBMC did not significantly differ among patient groups. The IFN-gamma production and the cytotoxicity against K562 cells, Raji cells, and a hepatocellular carcinoma, HuH-7 cells, greatly decreased in the cirrhotic liver MNC. In contrast, the cytotoxicity in PBMC did not significantly differ among the patient groups and was lower than that in the liver MNC of HCV (-) patients. CD56(+)T cells and NK cells but not regular T cells purified from liver MNC cultured with cytokines showed potent cytotoxicities against HuH-7 cells. These results suggest that a decreased number of CD56(+)T cells and NK cells in cirrhotic livers may be related to their susceptibility to hepatocellular carcinoma.

Aged↗