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Biomedical subjects

A Nakajima

Publications and source records attributed to A Nakajima.

At least 19 recordsLinked to original sources
PubMed2006

Increased risk of tuberculosis in patients with rheumatoid arthritis in Japan.

OBJECTIVE: To determine the risk for tuberculosis infection in patients with rheumatoid arthritis before the anti-cytokine era in Japan. PATIENTS AND METHODS: A database of a single-institute-based large observational cohort study for rheumatoid arthritis at the Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan, was analysed. Information on the history of tuberculosis infection was collected by patient self-reporting during April and October 2003. The age-adjusted incidence rate and relative risk for tuberculosis infection were investigated. RESULTS: Among 5044 patients with rheumatoid arthritis, 483 (9.6%) patients claimed to have a history of tuberculosis infection before October 2002. The frequency of history of tuberculosis increased according to the age of the patient. Four cases of new-onset tuberculosis were identified among 5544 patients with rheumatoid arthritis during 1 year. The age-adjusted incidence of tuberculosis was 42.4/100,000 patients. The relative risk for tuberculosis was 3.21 (95% confidence interval (CI) 1.21 to 8.55), and that of men and women was 10.59 (95% CI 3.42 to 32.78) and 1.41 (95% CI 0.2 to 10), respectively. CONCLUSION: There was an increased risk of tuberculosis infection in Japanese patients with rheumatoid arthritis, especially in male patients before the introduction of anti-tumour necrosis factor treatment. These data should form the basis for the risk management of anti-cytokine treatment in Japan.

Adult↗
PubMed2006

Preparation and sorption properties of porous materials from refuse paper and plastic fuel (RPF).

Porous materials consisting of activated carbon and amorphous CaO-Al(2)O(3)-SiO(2) (CAS) compound were prepared from refuse paper and plastic fuel (RPF), (a mixture of old paper and plastic) by carbonizing and/or activating treatments. Samples formed by chemical activation using K(2)CO(3) showed a high specific surface area (S(BET)) of 1330 m(2)/g but a lower ash content due to being washed after activation. By contrast, samples prepared by physical activation using steam showed rather lower S(BET) (510 m(2)/g) due to higher ash contents. The physically activated samples showed much higher uptake properties for Ni(2+) (a representative heavy metal) and phosphate ions (a representative of a harmful oxyanion) than the chemically activated samples because of the higher content of amorphous CAS in the former samples. By contrast, the chemically activated samples showed higher uptake for methylene blue (MB, a representative organic material) than the physically activated samples because of the higher activated carbon content of higher surface area. Although differences in the sorption properties for Ni(2+), phosphate ion and MB were found between the physically and chemically activated samples, both samples show excellent multiple sorption properties for cation-anion combinations and inorganic-organic sorbents.

Adhesives↗
PubMed2006

The role of TNFalpha and IL-17 in the development of excess IL-1 signaling-induced inflammatory diseases in IL-1 receptor antagonist-deficient mice.

IL-1 receptor antagonist (IL-1Ra)-deficient mice spontaneously develop several inflammatory diseases, resembling rheumatoid arthritis, aortitis, and psoriasis in humans. As adoptive T cell transplantation could induce arthritis and aortitis in recipient mice, it was suggested that an autoimmune process is involved in the development of diseases. In contrast, as dermatitis developed in scid/scid-IL-IRa-deficient mice and could not be induced by T cell transfer, a T cell-independent mechanism was suggested. The expression of proinflammatory cytokines was augmented at the inflammatory sites. The development of arthritis and aortitis was significantly suppressed by the deficiency of TNFalpha or IL-17. The development of dermatitis was also inhibited by the deficiency of TNFalpha. These observations suggest that TNFalpha and IL-17 play a crucial role in the development of autoimmunity downstream of IL-1 signaling, and excess IL-1 signaling-induced TNFalpha also induces skin inflammation in a T cell-independent manner.

Animals↗
PubMed2006

Reactive oxygen species mediate crosstalk between NF-kappaB and JNK.

The activation of NF-kappaB inhibits apoptosis via a mechanism involving upregulation of various antiapoptotic genes, such as cellular FLICE-inhibitory protein (c-FLIP), Bcl-xL, A1/Bfl-1, and X chromosome-liked inhibitor of apoptosis (XIAP). In contrast, the activation of c-Jun N-terminal kinase (JNK) promotes apoptosis in a manner that is dependent on the cell type and the context of the stimulus. Recent studies have indicated that one of the antiapoptotic functions of NF-kappaB is to downregulate JNK activation. Further studies have also revealed that NF-kappaB inhibits JNK activation by suppressing accumulation of reactive oxygen species (ROS). In this review, we will focus on the signaling crosstalk between the NF-kappaB and JNK cascades via ROS.

Animals↗
PubMed2006

Differential expression of peroxisome proliferator-activated receptor in histologically different human gastric cancer tissues.

Gastric cancer cell lines express peroxisome proliferator-activated receptor gamma (PPARgamma), and treatment with PPARgamma ligands suppresses growth of subgroup of these cell lines. However, expression and subcellular distribution of PPARgamma in human gastric cancer tissues is still unknown. Therefore, expression and subcellular localization of PPARgamma were examined among different histological types of gastric cancer tissues. Immunohistochemical staining for PPARgamma was performed using biopsy specimens of human gastric cancer of various histological types, gastric adenomas, and intestinal metaplasia. All samples of intestinal metaplasia and most samples of gastric tumors, except for signet ring cell carcinoma, expressed PPARgamma in the epithelial cells. Most samples of signet ring cell cancer lacked PPARgamma expression. All samples of intestinal metaplasia expressed PPARgamma only in the cytosol. For adenoma, 90% was positive for PPARgamma in cytosol, and 40% was positive in nuclei, for well-differentiated adenocarcinoma, 80% was positive in cytosol, and 20% was positive in nuclei. For moderately differentiated adenocarcinomas, 70% was positive for cytosol, and 80% was positive for nuclei; for poorly differentiated adenocarcinoma, 30% was positive in cytosol, and 70% was positive in nuclei. The frequency of samples with positive cytosolic staining decreased as the differentiation stage turned from intestinal metaplasia to adenoma, well-, moderately-, and poorly-differentiated cancers. Simultaneously, there was a tendency toward an increased frequency of samples with positive nuclear PPARgamma staining as the differentiation stage transformed from intestinal metaplasia to poorly-differentiated cancer. There was a striking difference in subcellular localization according to the differentiation levels of gastric dysplastic cells. The findings also supported an intestinal metaplasia-adenoma-well-differentiated gastric cancer sequence, and signet ring cell cancer was suggested to be of a different lineage from other types of gastric cancers.

Adenocarcinoma↗
PubMed2005

Mirthful laughter differentially affects serum pro- and anti-inflammatory cytokine levels depending on the level of disease activity in patients with rheumatoid arthritis.

OBJECTIVES: To examine the effect of mirthful laughter in rheumatoid arthritis (RA), we evaluated the levels of serum cytokines before and after patients experienced mirthful laughter. METHODS: Forty-one patients with RA and 23 healthy subjects were enrolled. They listened to 'Rakugo', a traditional Japanese comic story, to induce mirthful laughter. We measured serum IL-6, IL-1beta, TNF-alpha, IL-4 and IL-1 receptor antagonist (IL-1Ra) concentrations before and after patients listened to the story. The RA subjects were divided into two groups. One was designated the 'difficult-to-control RA' group (CRP > or =1.0 mg/dl); The other group was regarded as the 'easily controlled RA' group (CRP <1.0 mg/dl). RESULTS: The basal levels of serum IL-6 and TNF-alpha in the RA patients were significantly higher than those in the healthy group. After experiencing mirthful laughter, the levels of serum IL-6 decreased significantly in the RA group but not in the healthy subjects. Interestingly, the level of serum TNF-alpha decreased only in the easily controlled RA group. Serum IL-4 concentration in the RA group was significantly higher than that in healthy subjects before the story. After the story, the level of serum IL-4 significantly decreased in the RA group, especially in the difficult-to-control RA group. In contrast, serum IL-1Ra concentration was statistically higher in the RA group than that in healthy subjects before the story, and a further increase was observed after the story, especially in the easily controlled RA group. CONCLUSIONS: Our findings suggest that mirthful laughter affects the levels of serum pro- and anti-inflammatory cytokines differentially, depending on the RA disease activity.

Adult↗
PubMed2005

Preventive therapy for non-steroidal anti-inflammatory drug-induced ulcers in Japanese patients with rheumatoid arthritis: the current situation and a prospective controlled-study of the preventive effects of lansoprazole or famotidine.

BACKGROUND: There is a lack of evidence for the efficacy of preventive medications for peptic ulcers (PUs) among long-term users of non-steroidal anti-inflammatory drugs (NSAIDs) in Japan. AIM: To estimate the preventive effect by normal dose, not high-dose histamine-H2 receptor antagonists (H2RA) for NSAID-induced ulcers. METHODS: We designed two different studies to assess the efficacy of anti-ulcer agents in rheumatoid arthritis (RA) in patients treated over a long term with NSAIDs. An investigative survey divided patients into those not taking anti-ulcer agents (non-medication group); those taking mucosal protective agents (mucosal protectant group), H2RA (H2RA group), proton pump inhibitors (PPI group), or a prostaglandin E1 analog (PG) (PG group). The second study compared prospectively the preventive effects of either famotidine 20 mg bd (famotidine group) or lansoprazole 15 mg daily (lansoprazole group) in patients with PU scars. RESULTS: The prevalence of PU in the H2RA group was significantly lower compared to the mucosal protectant group (P < 0.05), and the mucosal protectant group was not significantly different to the non-medication group. The prospective study revealed that the PU onset rate of the famotidine group was 8% (1/13), and lansoprazole group was 15% (2/13), indicating no significant differences between the two. CONCLUSIONS: In Japan, normal-dose H2RA is expected to be a new PU preventive treatment strategy in patients requiring long-term NSAID therapy.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Hazardous ions uptake behavior of thermally activated steel-making slag.

This study concerns the utilization of waste steel-making slag, a by-product that contains mainly CaO, Fe(2)O(3) and SiO(2). The as-received slag was ground and thermally activated by temperature treatment from 110 to 1000 degrees C for 24 h. Although the as-received slag was amorphous, it became partially crystallized during grinding. These crystalline phases were larnite and iron oxide but other crystalline phases also appeared in addition to larnite after calcination. The uptake of Ni(2+), PO(4)(3-) and NH(4)(+) by the samples was investigated from solutions with initial concentrations of 10 mmol/l. The sample calcined at 800 degrees C showed the highest Ni(2+) uptake (4.85 mmol/g) whereas the highest simultaneous uptake of PO(4)(3-) (2.75 mmol/g) and NH(4)(+) (0.25 mmol/g) was achieved by calcining the material at 700 degrees C. The principal mechanism of Ni(2+) uptake is thought to involve replacement of Ca(2+) by Ni(2+). The mechanism of PO(4)(3-) uptake is mainly by formation of calcium phosphate while that of NH(4)(+) involves sorption by the porous silica surface of the samples.

Ammonia↗
PubMed2004

Characterization of binding between SF-1 and Sp1: predominant interaction of SF-1 with the N-terminal region of Sp1.

The transcription factor specificity protein 1 (Sp1) binds to GC boxes and interacts with many transcription factors to regulate gene expression. Steroidogenic factor-1 (SF-1) is an orphan nuclear receptor and plays a major role in regulation of the human steroidogenic acute regulatory (StAR) gene. We demonstrated that there is interaction between SF-1 and Sp1 on the human StAR promoter. In the present study, we examined the mechanism of the interaction between Sp1 and SF-1 on the human StAR gene promoter. Results of glutathione S-transferase (GST) pull-down assays and a mammalian two-hybrid assay showed that SF-1 interacted with Sp1 through the N-terminal domains of Sp1. Results of electrophoretic mobility shift assays using nuclear extracts showed that Sp1 is associated with SF-1-DNA complex formation. The density of SF-1-DNA complex was much greater when recombinant Sp1 was added to the incubation mixture. These results suggest that Sp1 interacts with SF-1 and that Sp1 enhances SF-1-DNA complex formation to regulate human StAR transcription.

Animals↗
PubMed2004

A G-quadruplex-interactive agent, telomestatin (SOT-095), induces telomere shortening with apoptosis and enhances chemosensitivity in acute myeloid leukemia.

Telomerase, the ribonucleoprotein enzyme maintaining the telomeres of eukaryotic chromosomes, is up-regulated in the vast majority of human neoplasias but not in normal somatic tissues. Therefore, the telomerase complex represents a promising universal therapeutic target in cancer. Telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to inhibit telomerase activity. We examined G-quadruplex interactive agent, telomestatin (SOT-095), for its ability to inhibit the proliferation of human leukemia cells, including freshly obtained leukemia cells. Telomere length was determined by either the terminal restriction fragment method or flow-FISH, and apoptosis was assessed by flow cytometry. Moreover, chemosensitivity was examined in telomestatin-treated U937 cells before ultimate telomere shortening. Treatment with telomestatin reproducibly inhibited telomerase activity in U937 and NB4 cells followed by telomere shortening. Enhanced chemosensitivity toward daunorubicin and cytosine-arabinoside was observed in telomestatin-treated U937 cells, before ultimate telomere shortening. Telomere shortening associated with apoptosis by telomestatin was evident in some freshly obtained leukemia cells from acute myeloid leukemia patients, regardless of sub-types of AML and post-myelodysplasia AML. These results suggest that disruption of telomere maintenance by telomestatin limits the cellular lifespan of AML cells, as well. However, in a minority of AML patients apoptosis was not evident, thus indicating that resistant mechanism might exist in some freshly obtained AML cells. Therefore, further investigation of telomestatin as a therapeutic agent is warranted.

Acute Disease↗
PubMed2003

Immunocytochemical evidence that amyloid beta (1-42) impairs endogenous antioxidant systems in vivo.

Amyloid beta, the major constituent of the senile plaques in the brains of patients with Alzheimer's disease, is cytotoxic to neurons and has a central role in the pathogenesis of the disease. We have previously demonstrated that potent antioxidants idebenone and alpha-tocopherol prevent learning and memory impairment in rats which received a continuous intracerebroventricular infusion of amyloid beta, suggesting a role for oxidative stress in amyloid beta-induced learning and memory impairment. To test the hypothesis, in the present study, we investigated alterations in the immunoreactivity of endogenous antioxidant systems such as mitochondrial Mn-superoxide dismutase, glutathione, glutathione peroxidase and glutathione-S-transferase following the continuous intracerebroventricular infusion of amyloid beta for 2 weeks. The infusion of amyloid beta (1-42) resulted in a significant reduction of the immunoreactivity of these antioxidant substances in such brain areas as the hippocampus, parietal cortex, piriform cortex, substantia nigra and thalamus although the same treatment with amyloid beta (40-1) had little effect. The alterations induced by amyloid beta (1-42) were not uniform, but rather specific for each immunoreactive substance in a brain region-dependent manner. These results demonstrate a cytological effect of oxidative stress induced by amyloid beta (1-42) infusion. Furthermore, our findings may indicate a heterogeneous susceptibility to the oxidative stress produced by amyloid beta.

Amyloid beta-Peptides↗
PubMed2003

Telomerase inhibition enhances apoptosis in human acute leukemia cells: possibility of antitelomerase therapy.

Telomerase is a ribonucleoprotein enzyme that maintains protective structures at the ends of eukaryotic chromosomes. We examined the impact of telomerase inhibition by the dominant-negative human catalytic subunit of telomerase (DN-hTERT) on the biological features of acute leukemia. We introduced vectors encoding dominant- negative (DN)-hTERT, wild-type (WT)-hTERT, or a control vector expressing only a drug-resistant marker into a telomerase-positive human acute lymphoblastic leukemia cell line, HAL-01. Expression of DN-hTERT dramatically inhibited telomerase activity, leading to apoptotic cell death. Mutant telomerase expression also enhanced daunorubicin-induced apoptosis. Nude mice (n=5 per group) received subcutanous implants of HAL-01 cells expressing the control vector or DN-hTERT or WT-hTERT. Implantation of HAL-01 cells expressing control vector (n=5) rapidly produced tumors, whereas implantation of those expressing DN-hTERT (n=5) did not. Thus, telomerase inhibition both growth of HAL-01 cells in vitro and tumorigenic capacity in vivo. Furthermore, the G-quadruplex-interactive telomerase-specific inhibitor, telomestatin, shortened the telomere length and induced apoptosis in freshly isolated primary acute leukemia cells. These results suggest that antitelomerase therapy may be useful in some acute leukemias in combination with antileukemic agents such as daunorubicin.

Acute Disease↗
PubMed2003

Phosphatidylinositol 3-kinase: a molecule mediating BDNF-dependent spatial memory formation.

Brain-derived neurotrophic factor (BDNF) plays a critical role in synaptic plasticity such as long-term potentiation (LTP), a form of synaptic correlate of learning and memory. BDNF is also implicated in learning and memory. We have demonstrated that radial arm maze training in rats for spatial learning and memory results in a significant increase in the BDNF mRNA expression in the hippocampus. Moreover, antisense BDNF oligonucleotide treatment impaired not only acquisition, but also maintenance and/or recall of spatial memory in the maze. Although these results suggest a role of BDNF for spatial memory processes, the signal transduction mechanisms that mediate the actions of BDNF remain unknown. Here we show that phosphorylation of BDNF receptor tyrosine kinase B (TrkB), phosphatidylinositol 3-kinase (PI3-K) and Akt, a target of PI3-K, in the hippocampus increased in parallel with spatial memory formation. Moreover, an activation of translational processes was suggested in the hippocampus after the maze training. When spatial learning was inhibited by antisense BDNF oligodeoxynucleotide, the activation was diminished. Chronic treatment with PI3-K inhibitor wortmannin impaired spatial learning. Our findings suggested that activation of TrkB/PI3-K and protein synthesis signaling pathway by BDNF in the hippocampus is important for spatial memory.

Androstadienes↗
PubMed2003

Tyrosine nitration of a synaptic protein synaptophysin contributes to amyloid beta-peptide-induced cholinergic dysfunction.

Amyloid beta (Abeta) is a critical factor involved in the pathogenesis of Alzheimer's disease (AD). We have previously demonstrated that continuous intracerebroventricular infusion of Abeta1-40 induced a time-dependent expression of the inducible nitric oxide (NO) synthase (iNOS) and an overproduction of NO in the rat hippocampus. The pathophysiological significance of the overproduction of NO on brain function was manifested by an impairment of nicotine-evoked acetylcholine(ACh) release and memory deficits.(4) Molecular mechanisms by which NO participates in the Abeta-induced brain dysfunction, however, remain to be determined. Here we show that chronic Abeta1-40 infusion caused a robust peroxynitrite formation and subsequent tyrosine nitration of proteins in the hippocampus. Immunoprecipitation and Western blot analyses further revealed that synaptophysin, a synaptic protein, was a main target of tyrosine nitration. Chronic infusion of Abeta1-40 resulted in an impairment of nicotine-evoked ACh release as analyzed by microdialysis. Daily treatment with the iNOS inhibitor aminoguanidine (AG) or the peroxynitrite scavenger uric acid (UA) prevented the tyrosine nitration of synaptophysin as well as the impairment of nicotine-evoked ACh release induced by Abeta. Our findings suggest that the tyrosine nitration of synaptophysin is related to Abeta-induced impairment of ACh release.

Acetylcholine↗
PubMed2002

Effect of hot water extract from Agaricus blazei Murill on antibody-producing cells in mice.

We investigated the immunopotentiating activities of boiled water-soluble extracts from desiccated Agaricus blazei Murill (ABM). Effect of ABM extract on antibody production was investigated by method of hemolytic plaque-forming cells (PFC) against sheep red blood cells (SRBC) antigen. ABM extracts significantly (p<0.01) increased the number of PFC in spleen with intraperitoneal administration at doses of 25 mg/kg as compared with control group. The populations of Mac-1- or CD25-positive cells significantly (p<0.01, p<0.001) increased, but in CD19-positive cells, there were no differences in ABM-treated mice as compared with control mice. The expressions of IL-6 and IL-1beta mRNA were augmented by ABM extract in both peritoneal macrophages and spleen cells. These results suggested that ABM extract might be an effective stimulator for T cell and macrophage to IL-1beta and IL-6 release, resulting in augmentation of antibody production against SRBC antigen.

Agaricus↗