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T Atsumi

Publications and source records attributed to T Atsumi.

At least 19 recordsLinked to original sources
PubMed2003

Effects of tea catechin inhalation on methicillin-resistant Staphylococcus aureus in elderly patients in a hospital ward.

We investigated the effects of inhalation of tea catechin on MRSA in the 24 elderly in patients, who were known to carry MRSA in sputum. The patients in the catechin group (N=12) were administered an inhalation of tea catechin extracts (in saline/bromhexine) (3.7 g/L catechins, 43% of them are composed of epigallocatechin gallate), three times daily with hand nebulizer for four weeks. The clinical effects were compared with the control group (N=12) who were given an inhalation of saline/bromhexine alone. After a week of the course, the numbers of the patients with decreased or disappearance of MRSA in their sputum was significantly higher in the catechin group, compared with that in the control group (seven vs. no patients; P<0.05). The number of patients discharged during the study was significantly increased, and the days of hospital stay were significantly decreased in the catechin group compared with those in the control group (six vs. one patient; P<0.05, 51+/-22 vs. 85+/-50 days, mean+/-S.D.;P <0.05, respectively). No adverse effects were observed in any patients during the study. Catechin inhalation seemed to be safe, and at least temporarily effective in the reduction of MRSA and shortening of hospitalization.

Activities of Daily Living↗
PubMed2003

Interaction between 2-ethoxybenzoic acid (EBA) and eugenol, and related changes in cytotoxicity.

The liquid of 2-ethoxybenzoic acid cements is composed of 2-ethoxybenzoic acid and eugenol (4-allyl-2-methoxyphenol). Recently, eugenol was reported to produce radicals at a higher pH, which consequently directly damages cells. We examined here whether eugenol radicals are generated from the mixture of eugenol/calcium hydroxide, and also whether 2-ethoxybenzoic acid or acetylsalicylic acid scavenges radicals, using electron spin resonance spectroscopy. Radicals were generated from the mixture of eugenol/calcium hydroxide in 50% dimethylsulfoxide solution. The radical intensity of eugenol in 50% dimethylsulfoxide with 0.1 M sodium bicarbonate buffer (pH 9.5) was dose-dependently reduced by 2-ethoxybenzoic acid, whereas it was enhanced by acetylsalicylic acid. Next, we investigated the cytotoxic effect of eugenol on 2-ethoxybenzoic acid, acetylsalicylic acid, or calcium hydroxide on human pulp fibroblasts or a human submandibular gland cancer cell line. The cytotoxicity of EBA was decreased, whereas that of acetylsalicylic acid was increased by eugenol. In contrast, that of calcium hydroxide was not affected by eugenol. Human pulp fibroblast but not human submandibular gland cells showed a high resistance against calcium hydroxide. The generation of eugenol radicals in the liquid of 2-ethoxybenzoic acid cements caused by oxidation may be suppressed by 2-ethoxybenzoic acid.

Aspirin↗
PubMed2002

Wnt-1 promotes neuronal differentiation and inhibits gliogenesis in P19 cells.

Wnt-1, the vertebrate counterpart of the Drosophila wingless gene, plays an important role in the early morphogenesis of neural tissues. In this report, we have shown that overexpression of Wnt-1 can direct embryonic carcinoma P19 cells to differentiate into neuron-like cells in the absence of retinoic acid. Immunocytochemistry showed that these cells expressed neuronal markers, such as the neurofilament (NF) and microtubule-associated protein 2 (MAP2), but failed to express the glial cell marker, glial fibrillary acidic protein (GFAP). RT-PCR revealed that two basic helix-loop-helix (bHLH) genes, Mash-1 and Ngn-1, were up-regulated during the differentiation stage of Wnt-1-overexpressing P19 cells. These results suggest that the Wnt-1 gene promotes neuronal differentiation and inhibits gliogenesis during the neural differentiation of P19 cells, and that neural bHLH genes might be involved in this process.

Animals↗
PubMed2002

Tyrosine 759 of the cytokine receptor gp130 is involved in Listeria monocytogenes susceptibility.

Interleukin-6 family cytokines have been implicated in adaptive and innate immunity, hematopoiesis, and inflammation. This cytokine family shares a signal-transducing receptor subunit called gp130. gp130(F759/F759) knockin mice carry a point mutation at the SHP2-binding site of gp130 due to the replacement of tyrosine-759 (Y759 for human gp130) with phenylalanine (F). To explore the effect of this point mutation on the host response to bacterial infection, gp130(F759/F759) knockin mice were infected with Listeria monocytogenes. gp130(F759/F759) knockin mice began to die at 3 to 4 days post infection (p.i.) and showed higher mortality than did controls. Listeria titers at 3 days p.i. in the peritoneal cavity, spleen, and liver were significantly higher in gp130(F759/F759)knockin mice than in controls. Nitric oxide production, upregulation of the mRNA levels of a variety of cytokines, and listericidal activity in gp130(F759/F759) macrophages were unchanged. However, gp130(F759/F759) knockin mice displayed significantly lower levels of interferon (IFN)gamma in serum and in the culture supernatant from peritoneal exudate cells and splenocytes, in response to Listeria infection. These results suggest that the Y759 point mutation in gp130 attenuates the early phase of defense against Listeria infection, possibly owing to insufficient elevation of IFNgamma levels, and thus gp130 is a possible candidate gene for Listeria susceptibility.

Animals↗
PubMed2002

Significance of magnetic resonance imaging in the diagnosis of nodular regenerative hyperplasia of the liver complicated with systemic lupus erythematosus: a case report and review of the literature.

Nodular regenerative hyperplasia of the liver (NRH), characterized by multiple hepatic nodules in the absence of fibrosis, is a rare but important complication of systemic lupus erythematosus (SLE) associated with non-cirrhotic portal hypertension. The diagnosis of NRH is based on the pathological examination, and radiological findings of NRH are poorly documented. We report a case of a 40-year-old woman with SLE complicated with NRH. Sixteen years after diagnosis of SLE, esophageal varices were incidentally found and diagnosis of portal hypertension due to NRH was made by magnetic resonance imaging (MRI) and confirmed by needle liver biopsy. Although MRI showed the lesions as significant nodules, neither computed tomography nor ultrasonography could demonstrate the nodules. However, serial MRI showed significant enlargement of the nodules for 2 years Because NRH may lead to portal hypertension with life-threatening variceral haemorrhage in patients with SLE, MRI is a useful, non-invasive examination to screen the patients for its presence and follow-up. We reviewed the literature regarding NRH in SLE and discuss the management of the affected patients.

Adult↗
PubMed2001

An ultrasonic motor model for bacterial flagellar motors.

A model for the transduction of energy occurring in bacterial flagellar motors is presented. In this model, the influx of ions across the channel causes the cyclic conformational change of the channel itself, which in turn produces travelling waves in one of the subcomponents of the motor, the C ring. This wave stabilizes the cyclical movement of the channel which generates the rotating force. The estimated frequency of cyclic conformational change is between 36 kHz and 6.3 MHz, i.e. in the ultrasonic range. This phenomenon is therefore referred to as the ultrasonic micromotor of microorganisms.

Animals↗
PubMed2001

A role of N-cadherin in neuronal differentiation of embryonic carcinoma P19 cells.

N-cadherin is one of the important molecules for cell to cell interaction in the development of the central nervous system (CNS). In this report, we have shown that N-cadherin mRNA and protein were increased rapidly in retinoic acid (RA)-induced neuronal differentiation of embryonic carcinoma P19 cells. To explore possible roles for N-cadherin during this process, N-cadherin-overexpressing P19 cell lines were established. These transfected cells could differentiate into neurofilament-expressing neurons in the absence of RA. RT-PCR revealed that the expression patterns of development-related genes, such as Oct-3/4, nestin, Notch-1, and Mash-1 were similar between the transfected P19 cells and the RA-induced wild-type P19 cells during their neuronal differentiation. On the contrary, the Wnt-1 gene was up-regulated in the N-cadherin-overexpressing P19 cells, but could not be detected in the wild-type P19 cells. These results suggest N-cadherin may play a role in neuronal differentiation of P19 cells, possibly through the Wnt-1 signaling pathway.

Animals↗
PubMed2001

The role of basal ganglia in reinforcement learning and imprinting in domestic chicks.

Effects of bilateral kainate lesions of telencephalic basal ganglia (lobus parolfactorius, LPO) were examined in domestic chicks. In the imprinting paradigm, where chicks learned to selectively approach a moving object without any explicitly associated reward, both the pre- and post-training lesions were without effects. On the other hand, in the water-reinforced pecking task, pre-training lesions of LPO severely impaired immediate reinforcement as well as formation of the association memory. However, post-training LPO lesions did not cause amnesia, and chicks selectively pecked at the reinforced color. The LPO could thus be involved specifically in the evaluation of present rewards and the instantaneous reinforcement of pecking, but not in the execution of selective behavior based on a memorized color cue.

Animals↗
PubMed2001

Stem cell factor and interleukin-3 induce stepwise generation of erythroid precursor cells from a basic fibroblast growth factor-dependent hematopoietic stem cell line, A-6.

A multipotent immature myeloid cell population was produced from a basic fibroblast growth factor (bFGF)-dependent hematopoietic stem cell line, A-6, when cultured with stem cell factor (SCF) replacing bFGF. Those cells were positive for stem cell markers, c-kit and CD34, and a myeloid cell marker, F4/80. Some cell fractions were also positive for Mac-1, a macrophage marker or Gr-1, a granulocytic maker, but negative for an erythroid marker TER119. They also showed the expression of mRNA for the myeloid-specific PU.1 but did not that for the erythroid-specific GATA-1. Among various cytokines, interleukin-3 (IL-3) induced erythroid precursor cells that expressed the erythroid-specific GATA-1 and beta-major globin. The quantitative analysis showed that erythroid precursor cells were newly produced from the immature myeloid cells by cultivation with IL-3. SCF and IL-3 induced stepwise generation of erythroid precursor cells from an A-6 hematopoietic stem cell line.

Animals↗
PubMed2001

The production of reactive oxygen species by irradiated camphorquinone-related photosensitizers and their effect on cytotoxicity.

Camphorquinone (CQ) is widely used as an initiator in modern light-cured resin systems but there are few reports about its effects on living cells. To clarify the mechanism of photosensitizer-induced cytotoxicity, the production of initiator radicals and subsequent reactive oxygen species (ROS) by CQ, benzil (BZ), benzophenone (BP), 9-fluorenone (9-F) in the presence of the reducing agent (2-dimethylaminoethyl methacrylate or N,N-dimethyl-p-toluidine, DMT) with visible-light irradiation was examined in a cell or cell-free system. Initiator radical production was estimated by the reduction rate of 1,1-diphenyl-2-picrylhydrazyl and by the conversion of poly-triethyleneglycol dimethacrylate; the results indicated that CQ/DMT had the highest activity among them. The cytotoxic effects of the photosensitizers on both human submandibular gland (HSG) adenocarcinoma cell line and primary human gingival fibroblast (HGF) showed that the 50% toxic concentration (TC(50)) declined in the order: CQ>BP>9-F>BZ. ROS produced in HSG or HGF cells by elicited, irradiated photosensitizers were evaluated in two different assays, one using adherent cell analysis and sorting cytometry against adherent cells and the other, flow cytometry against floating cells, with fluorescent probes. ROS production was dose- and time- dependent, and declined in the order: BZ>9-F>BP>CQ. Cytotoxic activity was correlated with the amount of ROS. Cytotoxicity and ROS generation in HGF cells was significantly lower than in HSG cells. ROS induced by aliphatic ketones (CQ) were efficiently scavenged by hydroquinone and vitamin E, whereas those by aromatic ketones (9-F) were diminished by mannitol and catalase, suggesting that OH radicals were involved in ROS derived from 9-F. A possible link between the cytotoxic activity and ROS is suggested.

Antioxidants↗
PubMed2001

Reactive oxygen species generation and photo-cytotoxicity of eugenol in solutions of various pH.

In order to clarify the mechanism of photo-damage caused by eugenol (4-allyl-2-methoxyphenol), we measured cell survival in the presence of eugenol at concentrations of 10(-3) - 10(-7) M, with and without VL (visible light) irradiation by a VL dental lamp and at various pHs (7.2, 7.8 and 8.2) using two different cells (HSG, a human submandibular gland tumor cell line; HGF, a human gingival fibroblast in primary culture). Also, ROS (reactive oxygen species) generation in the above adherent single cells was measured by ACAS laser cytometry combined with CDFH-DA, a peroxide probe. The survival of both HSG and HGF cells treated with eugenol was significantly decreased as the VL irradiation time and/or the pH of the medium was increased. The amount of ROS generated from eugenol was also enhanced by increasing the VL irradiation time and elevating the pH of the medium. Cytotoxicity and ROS generation of HGF cells were significantly lower than that of HSG cells. Glutathione (1 mM) or cysteine (1 mM) protected the photo damages. We conclude that the cytotoxicity of VL-irradiated eugenol possibly was caused by the generation of eugenol radicals and additionally by ROS, both of which were produced dependent on the dose of eugenol, length of irradiation time, and pH of the medium.

Carcinoma, Squamous Cell↗
PubMed2001

Genetics of antiphospholipid syndrome.

The mechanisms of thrombosis in antiphospholipid syndrome (APS) are highly heterogeneous and multifactorial, and some genetic factors may be involved in its pathophysiology. The genetic variants of representative antigen, beta 2-glycoprotein I (beta 2GPI), have been known, and valine/leucine247 polymorphism is a genetic risk for having anti beta 2GPI antibodies and APS. Congenital beta 2GPI deficiency did not correlate with thrombophilia, thus its responsible gene (beta 2GPI-Sapporo) was not a risk for thrombosis. Many other thrombosis-related genetic factors have been investigated in APS, but no additional risk for thrombosis has been indicated in patients with antiphospholipid antibodies.

Antibodies, Antiphospholipid↗
PubMed2001

Anti-phosphatidylserine/prothrombin antibodies are not frequently found in patients with unexplained recurrent miscarriages.

OBJECTIVE: To determine whether the presence of anti-phosphatidylserine/ prothrombin antibodies (anti-PS/PT) can be a major factor in otherwise unexplained recurrent miscarriages. PATIENTS AND METHODS: Eighty-one consecutive patients with history of 2 or more recurrent miscarriages were studied. Patients with history of overt thrombotic events were not included. Patients were examined for plausible causes of miscarriages, and titer of IgG, IgM and IgA anti-PS/PT were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Thirty-five patients had one or more plausible causes of recurrent miscarriages, including 12 positive for well-established anti-phospholipid antibodies, such as anti-beta2-glycoprotein I. None of the patients included in this study was found to be positive for anti-PS/PT. CONCLUSION: Detection of anti-PS/PT in addition to other anti-phospholipid antibodies does not seem to aid in the evaluation of patients with unexplained recurrent miscarriages.

Abortion, Habitual↗
PubMed2001

Mannose-binding lectin gene: polymorphisms in Japanese patients with systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome.

Mannose-binding lectin (MBL) is a key element of the innate immunity, with a structure similar to complement C1q. Serum MBL levels are greatly affected by the polymorphisms of the MBL gene. In particular, codon 54 mutation of the MBL gene results in a significant reduction of serum MBL. To determine whether polymorphism of the MBL gene is associated with occurrence of systemic lupus erythematosus (SLE), rheumatoid arthritis and Sjögren's syndrome in the Japanese population, we analyzed the MBL gene polymophisms of these patients and controls, by polymerase chain reaction-restriction fragment length polymorphism methods. We found that patients studied had a significantly higher frequency of having homozygous codon 54 mutation compared to controls. In particular, patients with SLE or Sjögren's syndrome showed higher probabilities of being homozygous for this mutation. Among subjects with the same genotype, SLE patients tended to have higher serum MBL concentration than controls. Analysis of the promotor region suggested that SLE patients heterozygous for the codon 54 mutation have a higher probability of having a low producing haplotype for the gene without the codon 54 mutation. We conclude that persons homozygous for codon 54 mutation of the MBL gene may be prone to occurrence of autoimmune disorders including SLE, in the Japanese. MBL may have protective effects on occurrence and progression of SLE.

Arthritis, Rheumatoid↗
PubMed2001

Cytotoxicity and phospholipid-liposome phase-transition properties of 2-hydroxyethyl methacrylate (HEMA).

To elucidate the cytotoxic induction mechanisms of the hydrophilic HEMA, the comparative cytotoxic activities of HEMA and the hydrophobic monomers TEGDMA and MMA were studied, using erythrocytes, gingival fibroblasts and a salivary gland carcinoma cell line. Also, the gel-to-fluid phase transition properties (i.e. temperature, Tm; cooperativity, H/HHW; enthalpy, deltaH) of dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol (CS) liposomes (as a model for biological membranes) induced by methacrylates were investigated, using differential scanning calorimetry (DSC). In addition, the methacrylate-chemical-shifts in DPPC liposomes were assayed using NMR spectroscopy. Both the hemo lytic and cytotoxic activity declined in the order: TEGDMA> HEMA>MMA. The changes in Tm increased in the order: HEMA >TEGDMA, while in contrast, that of HEMA was slightly increased without changes in the deltaH. The DSC changes in DPPC/CS liposomes with HEMA were the largest of those recorded. The cytotoxicity of HEMA may be induced by the hydrophobic interaction derived from the molecular association of OH groups of HEMA and, in addition, by the preferential interaction with CS.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2001

Radical production and cytotoxic activity of tert-butyl-substituted phenols.

2,4,6-Tri-tert-butylphenol (TBP)-related compounds are used for stabilizing plastics by making them resistant to oxidation. However, the cytotoxic activity of these compounds has not yet been established. TBP produced phenoxyl radicals at pH >or= 9.0 and 2,4-di-t-butylphenol (DBP) at pH 12.5, but 3,3',5,5'-tetra-t-butyl-1,1'-biphenyl-2,2'-diol (bisDBP) did not, using ESR spectroscopy. Both superoxide anion radical (O(2)(-)) scavenging activity and reactive oxygen species (ROS) production activity declined in the order of TBP > DBP > bisDBP. The cytotoxic activity against human oral tumor cell lines (HSC-2, HSG) and human gingival fibroblast cells (HGF) declined in the order of DBP >> bisDBP = TBP = TBP-OOH (2,4,6-tri-t-butyl-4-hydroperoxy-2,5-cyclohexadiene-1-one). The cytotoxic activity of TBP, but not of DBP or bisDBP was significantly enhanced after visible light (VL)-irradiation for 10 min. The cytotoxicity of irradiated TBP was significantly higher than that of either original TBP or TBP-OOH, the oxidative metabolite of TBP, possibly due to the formation of TBP stable radical and ROS via oxidation. In contrast, the cytotoxic activity of DBP and bisDBP was independent of radical production, and therefore, may be intrinsic. A non-enzymatic oxidation decomposition of DBP or TBP was estimated from the formation of reaction enthalpy (DeltaH) using a modified neglect of diatomic overlap, parametric method 3 (MNDO-PM3) semi-empirical method, suggesting that O(2) is capable of activating DBP to a reactive quinone or dimer and that TBP phenoxyl radicals via oxidation directly affect extra- or intracellular bioactive materials, resulting in the induction of cytotoxicity.

Antioxidants↗
PubMed2001

HLA class II gene polymorphisms in antiphospholipid syndrome: haplotype analysis in 83 Caucasoid patients.

OBJECTIVES: We investigated the association between HLA class II haplotypes and antiphospholipid syndrome (APS). METHODS: HLA DRB1, DQB1 and DQA1 genotypes were determined by the polymerase chain reaction using sequence-specific primers in 83 Caucasoid British patients with APS. The genotype frequencies were compared between subgroups of patients and 177 healthy controls. RESULTS: DQB1*0604/5/6/7/9-DQA1*0102-DRB1*1302 and DQB1*0303-DQA1*0201-DRB1*0701 haplotypes showed significantly positive correlations with APS [P=0.0087 and P=0.0012, respectively]. The association of the former was enhanced in primary APS patients with anti-beta 2-glycoprotein I antibodies (anti-beta 2GPI) [odds ratio 6.2, 95% confidence interval (2.2-17.6), P=0.0014, corrected P=0.042]. CONCLUSIONS: These alleles and haplotypes might affect anti-ss2GPI production and APS development in different and heterogeneous fashion.

Adolescent↗