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Biomedical subjects

Shunichi Kumagai

Publications and source records attributed to Shunichi Kumagai.

At least 19 recordsLinked to original sources
PubMed2007

Is SS-A/Ro52 a hydrogen peroxide-sensitive signaling molecule?

SS-A/Ro52 (Ro52) protein is one of the targets of autoantibodies in Sjogren's syndrome and systemic lupus erythematosus. Ro52 structurally belongs to the RING-B-box/coiled-coil family, which appears to carry out diverse functions, but the physiological function of Ro52 remains largely unknown. Here, the authors demonstrate that hydrogen peroxide but not other oxidative stressors induced translocation of Ro52 protein from the cytoplasm to the nucleus and this phenomenon was attenuated by inhibition of MAP kinases, ERK in particular. These findings raise the possibility that SS-A/Ro52 may function as a hydrogen peroxide-selective, oxidative stress-sensitive signaling molecule that is activated via the MAP kinase pathway.

Cells, Cultured↗
PubMed2006

HLA-DR-negative AML (M1 and M2): FLT3 mutations (ITD and D835) and cell-surface antigen expression.

FLT3 mutations and cell-surface antigen were investigated in 29 DR-negative (DR(-)) M1/M2 AML samples in comparison with 30 DR-positive (DR(+)) M1/M2 AML samples. FLT3-ITD was detected in 59.3% and D835 was detected in 7.4% of the samples. The incidence of FLT3-ITD was higher in the DR(-) group (59.3%) than in the DR(+) group (17.9%; P=0.002). The DR(-) status was associated with the CD34(-) (82.8%), CD7(-) (92.9%) and CD45RO(+) status (76%). Our results indicated that FLT3 mutation is the most common gene alteration found in the DR(-) M1/M2 AML. These results are important for further characterizing this phenotypic AML entity.

Amino Acid Sequence↗
PubMed2006

Serum cystatin C levels to predict serum concentration of digoxin in Japanese patients.

Cystatin C (Cys-C) has been recently paid great attention as a better endogenous marker of the glomerular filtration rate than creatinine (Cr). In this study, the usefulness of Cys-C was compared with Cr in terms of the estimation of the steady-state serum trough concentrations of digoxin in Japanese patients. Forty patients treated with digoxin and 56 healthy elderly subjects were participated in this study. The serum levels of Cys-C and Cr in the patients were higher than those in the healthy elderly subjects, but the increase of Cys-C was more predominant in the patients. Their levels were well-correlated for both of the healthy elderly subjects (r=0.691) and patients (r=0.774), but the serum concentrations of digoxin were better correlated with those of the reciprocal values of Cr (r=0.667) than those of Cys-C (r=0.383), presumably due to the fact that digoxin and Cr were excreted via both glomerular filtration and tubular secretion. Cys-C is useful for the substratification of the patients diagnosed to have normal renal function with Cr of < 1.3 mg/dL into those with normal and pseudo-normal renal function, resulting in the corresponding serum concentrations of digoxin.

Journal Article↗
PubMed2006

Performance evaluation and cross-reactivity from insulin analogs with the ARCHITECT insulin assay.

BACKGROUND: Insulin measurement is used for the diagnosis of hypoglycemia and for insulin pharmacokinetic evaluations. We assessed the analytical and clinical performance of the ARCHITECT insulin assay, a chemiluminescent immunoassay recently introduced for the ARCHITECT i2000 fully automated immunoassay analyzer (Abbott Laboratories). We also tested whether major insulin analogs cross-reacted with the immunoassay reagents. METHODS: We used Clinical and Laboratory Standards Institute protocols to assess the analytical performance of the ARCHITECT insulin assay and compared its accuracy with that of the E-test TOSOH II (IRI) from TOSOH Corporation. We used 3 recombinant insulin analogs (lispro, aspart, and glargine) to evaluate the cross-reactivity of insulin analogs with the ARCHITECT immunoassay reagent. RESULTS: The total CV for the ARCHITECT assay was < 5%. Correlation between the ARCHITECT insulin assay and the E-test TOSOH II (IRI) was satisfactory in the measured range, but we detected a slope deviation between the assays. The ARCHITECT insulin assay showed low cross-reactivity to the insulin analog aspart, whereas it detected the other insulin analogs, lispro and glargine, in concentrations as high as the theoretical concentrations. CONCLUSIONS: The ARCHITECT insulin assay showed favorable basic performance, including reproducibility, dilution linearity, detection limit, and effects of interfering substances. When interpreting results, clinicians and laboratory pathologists should be aware of the cross-reactivity of the ARCHITECT and other immunoassays to specific insulin analogs prescribed to diabetes patients.

Autoanalysis↗
PubMed2006

Decreased susceptibility to fluoroquinolones and gyrA gene mutation in the Salmonella enterica serovar Typhi and Paratyphi A isolated in Katmandu, Nepal, in 2003.

Typhoid fever is the most common clinical diagnosis among febrile patients presenting to hospital in Katmandu. Salmonella enterica serovar Typhi (S. enterica serovar Typhi) and Salmonella enterica serovar Paratyphi A (S. enterica serovar Paratyphi A) with decreased susceptibility to fluoroquinolones and resistance to nalidixic acid are common in recent years. In the present study, we examined the in vitro susceptibility to fluoroquinolones and the presence of gyrA gene mutations in 30 clinical strains of S. Typhi and 39 of S. Paratyphi A, all of which were isolated in Katmandu, Nepal, in 2003. In those strains, we found that 73.3% and 94.9% of S. Typhi and S. Paratyphi A strains contained gyrA gene mutation, and showed the resistance to a quinolone, nalidixic acid, and decreased susceptibility to fluoroquinolones, ciprofloxacin, and levofloxacin. Although fluoroquinolones may still be useful as antibiotics for the treatment of typhoid fever, clinicians should be aware of the possibility of treatment failures of infections with S. Typhi and S. Paratyphi A strains with decreased susceptibility to fluoroquinolones.

Anti-Bacterial Agents↗
PubMed2006

Thioredoxin protects against joint destruction in a murine arthritis model.

Thioredoxin (TRX) is an oxidative stress-inducible biological antioxidant that is highly expressed in the synoviocytes of rheumatoid arthritis (RA) patients. There is much evidence that oxidative stress plays a key role in the inflammation and destruction of RA joints; the functional relationship between TRX and RA remains unknown, however. We therefore investigated the role played by TRX in the inflammatory and joint-damaging processes of RA using a murine model in which arthritis was induced by administering a mixture of anti-type II collagen monoclonal antibodies (mAb) and lipopolysaccharide (LPS). In Wt mice mAb/LPS injection induced neutrophil infiltration, cartilage destruction, and chondrocyte apoptosis within the joints, all of which were dramatically suppressed in TRX transgenic (TRX-Tg) mice. Moreover, the 8-hydoxy-2'-deoxyguanosine (8-OHdG) expression seen in Wt mice after mAb/LPS injection was almost completely inhibited in TRX-Tg mice. The administration of recombinant TRX also suppressed mAb/LPS-induced joint swelling in Wt mice. Taken together, these results suggest that TRX protects against arthritis and is a plausible candidate with which to develop novel therapies for the treatment of RA.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2006

A pediatric patient with neuro-Behçet's disease.

Behçet's disease is rare in childhood. We describe a 10-year-old boy with neuro-Behçet's disease (NB) who presented with fever, headache, vertigo, and hearing loss. An examination of the cerebrospinal fluid (CSF) revealed pleocytosis as well as elevated protein and interleukin (IL)-6 levels. Brain magnetic resonance imaging (MRI) showed hyperintensity of the right thalamus and midbrain on T2-WI, and gadolinium (Gd) enhancement of left acoustic nerve origin. HLA-B51 was positive. Prednisolone combined with methotrexate resulted in a complete remission. Brain MRI and the CSF IL-6 level were useful for the diagnosis and monitoring of this pediatric patient with NB.

Behcet Syndrome↗
PubMed2006

Rituximab combined with a small dose of melphalan for a refractory follicular lymphoma patient.

A 48-year-old male patient with follicular lymphoma, grade II, stage IV, was treated with CHOP, ESHAP and MACOP-B, resulting in partial remission. After 9 months, the disease progressed and several chemotherapy agents, including three courses of rituximab combined with etoposide, sobuzoxane or methotrexate, only resulted in a stable disease response. However, the fourth course of rituximab combined with a small dose of melphalan produced excellent results and the complete response continued for more than 15 months. It is possible that these two drugs may act synergistically.

Antibodies, Monoclonal↗
PubMed2006

Primary levofloxacin resistance and gyrA/B mutations among Helicobacter pylori in Japan.

BACKGROUND: Recent years have witnessed a decrease in the rate of Helicobacter pylori eradication due to antimicrobial resistance, clarithromycin or metronidazole resistance in particular. As one of the alternatives to the standard regimens, levofloxacin-containing therapy has been considered a promising regimen. Nevertheless, there is a little information concerning the prevalence of levofloxacin resistance and this resistance mechanism. MATERIALS AND METHODS: Levofloxacin susceptibility was examined using E-test in 507 H. pylori strains clinically isolated in Japan from 2001 to 2004. Mutation patterns in the quinolone resistance-determining regions of the gyrA and gyrB genes were evaluated, performing direct sequencing of 68 levofloxacin-resistant and 50 susceptible strains. RESULTS: Primary levofloxacin resistance was found in 76 (15.0%) strains. Fifty-seven (83.8%) of 68 levofloxacin-resistant strains analyzed had point mutations in gyrA at Asn-87 or Asp-91, while seven (14.0%) of 50 susceptible strains had gyrA mutations. There was a significant difference in the occurrence of gyrA mutations between levofloxacin-resistant and -susceptible strains (p < .001). In levofloxacin-resistant strains, the occurrence of gyrA mutations at Asn-87 was most common regardless of minimal inhibitory concentration levels, and that of gyrA mutations at Asp-91 tended to be associated with low-level resistance. A double gyrA mutation at Asn-87 and Asp-91 might have an additional impact. As for gyrB, three (4.4%) of 68 levofloxacin-resistant strains with no susceptible strains had mutations. CONCLUSIONS: Primary levofloxacin resistance was common in Japan and primarily related to gyrA mutations at Asn-87 and Asp-91.

Adult↗
PubMed2006

The lipoprotein fraction between VLDL and LDL detected by biphasic agarose gel electrophoresis reflects serum remnant lipoprotein and Lp(a) concentrations.

We analyzed lipoprotein profiles in 616 Japanese by biphasic agarose gel electrophoresis using Chol/Trig Combo(TM) to yield HDL, VLDL, LDL and CM fractions which were stained with cholesterol and triglyceride reagents, respectively. To further evalute the pattern of electrophoresis, we analyzed the fraction between VLDL and LDL to confirm the possibility of a MidBand by using an automatic-five-fraction function. The cholesterol concentrations in MidBand (MidBand-C) showed a good correlation to remnant-like particle-cholesterol (RLP-C) (r = 0.95) in 23 consecutive samples (TC < 220 mg/dl, Lp(a) < 30 mg/dl). However, MidBand-C concentrations of subjects with high Lp(a) levels (Lp(a) > 30 mg/dl) were also high compared to RLP-C concentrations. The average MidBand-C levels in elderly normolipidemic control subjects (TC < 220, TG < 150) were 5.2 +/- 2.4 mg/dl in 30 males (mean age, 70 +/- 10 years) and 5.4 +/- 2.0 mg/dl in 40 females (64 +/- 11 years). The average MidBand-C levels of normolipidemic patients with coronary artery diseases (CAD; TC < 220, TG < 150) were 9.4 +/- 4.1 mg/dl in 126 males (mean age, 66 +/- 10 years) and 9.1 +/- 4.0 mg/dl in 44 females (67 +/- 10 years). These levels were significantly higher than control values (p < 0.0001). Areas under ROC curves were greater for MidBand-C than for TC, LDL-C and TG when used to discriminate between the patients with CAD and normolipidemic control subjects for each sex. There results suggest that the MidBand-C level may be useful as an indicator of risk for CAD.

Adult↗
PubMed2006

Trichostatin A cooperates with Fas-mediated signal to induce apoptosis in rheumatoid arthritis synovial fibroblasts.

OBJECTIVE: To clarify the effects of trichostatin A (TSA), a histone deacetylase inhibitor, on the growth and survival of rheumatoid arthritis synovial fibroblasts (RA-SF). METHODS: Cell viability was assessed using a WST-8 assay and direct cell counting. Apoptosis was detected by annexin V staining on a flow cytometer. Protein and mRNA expression was determined by Western blotting, flow cytometry, and RT-PCR. RESULTS: TSA suppressed cell growth of RA-SF in a dose-dependent manner, as determined by WST-8 assay and direct cell counting. Other histone deacetylase inhibitors also showed inhibitory effects on RA-SF proliferation. TSA upregulated p21(WAF1/CIP1) cell cycle inhibitor, suggesting that cell cycle arrest is involved in the reduction of cell numbers. In addition, TSA cooperated with Fas-induced pathway to induce cell death, determined by WST-8 assay and annexin V staining. TSA reduced FLICE inhibitory protein (FLIP) expression but not Bcl-2, Bcl-XL, and Fas expression, indicating that the synergistic effect may be through downregulation of FLIP. CONCLUSION: TSA has antirheumatic effects on RA-SF and might be a potential therapeutic tool for the treatment of RA.

Apoptosis↗
PubMed2006

[Effects of magnetic resonance imaging on neutrophil functions].

We evaluated the effects of magnetic resonance (MR) imaging on human neutrophil functions. In addition of the counting of leukocyte and neutrophil number, expression levels of adhesion molecules on neutrophil surface such as CD11b and L-selectin, and reactive oxygen species (ROS) production were determined by means of flowcytometry. Complete blood count did not show any difference between before and after MR imaging in five normal healthy volunteers. The levels of cell surface adhesion molecules were not altered in both in vivo MR imaging (n=5) and in vitro MR exposure experiments (n=13). Moreover, the levels of ROS production were also not affected by in vivo MR imaging. On the other hand, neutrophils exposed to MR in vitro exhibited significant increase in ROS production after stimulation with fMLP combined with lipopolysaccharide, although no increase was observed with PMA stimulation. Actually, there have been no reports describing the complication relating to hyper-neutrophil function as far as we could search, but it might be necessary to evaluate the biological effects of MR imaging especially under the pathologic circumstances that induce neutrophil activation.

Adult↗
PubMed2006

[Contribution of medical technologists in team medical care of diabetics].

For the effective treatment of diabetic mellitus (DM), patients are encouraged to self-manage their disease according to the doctor's instructions and advice from certified diabetes educators (CDE) and other comedical staff. Therefore, the cooperation of medical staff consisting of a doctor, CDE, nurse, pharmacist, dietitian, and medical technologist is important for DM education. Medical technologists licensed for CDE (MT-CDE) have been participating in the DM education team in Kobe University Hospital since 2000. MT-CDE are in charge of classes for medical tests, guidance for self-monitoring of blood glucose and teaching how to read the fluctuation graph of the blood glucose level in the education program for hospitalized DM patients. MT-CDEs teach at the bedside how to read the results of medical tests during the first few days of hospitalization using pamphlets for medical tests. The pamphlets are made comprehensible for patients by using graphics and photographs as much as possible. It is important to create a friendly atmosphere and answer frank questions from patients, since they often feel stress when having medical tests at the early stage of hospitalization. This process of questions and answers promotes their understanding of medical tests, and seems to reduce their anxiety about having tests. We repeatedly evaluate their level of understanding during hospitalization. By showing them the fluctuation graph of the glucose level, patients can easily understand the status of their DM. When prescriptions are written on the graph, their therapeutic effects are more comprehensible for the patients. The items written on the graph are chosen to meet the level of understanding of each patient to promote their motivation. In summary, the introduction of MT-CDE has been successful in the education program for DM patients in our hospital. We plan to utilize the skills and knowledge of MT-CDE more in our program so that our DM education program will help patients cope with life with DM.

Blood Glucose Self-Monitoring↗
PubMed2005

Albumin attenuates neutrophil activation induced by stimulators including antibodies against neutrophil-specific antigens.

As neutrophil activation is related to several adverse transfusion reactions, we studied about the activation induced by anti-neutrophil antibodies and the stabilizing effects of albumin pretreatment by means of flow cytometry. Anti-neutrophil monoclonal antibody (anti-HNA-1a, 1b, 2a) alone induced CD11b expression and shedding of L-selectin, and anti-HNA-1a reinforced reactive oxygen species (ROS) production. Albumin pretreatment significantly reduced CD11b expression and L-selectin shedding induced by fMLP and ROS production induced by PMA, G-CSF combined with PMA or LPS-fMLP, or anti-HNA-1a combined with PMA. These findings suggest that anti-HNA-1a is related to adverse reactions and albumin has a regulating effect on neutrophil activation.

Antibodies, Monoclonal↗
PubMed2005

Humanized anti-interleukin-6 receptor antibody treatment of multicentric Castleman disease.

Multicentric Castleman disease (MCD) is an atypical lymphoproliferative disorder characterized by systemic lymphadenopathy and constitutional inflammatory symptoms. Dysregulated overproduction of interleukin-6 is responsible for the clinical abnormalities. This multicenter prospective study was undertaken to evaluate the safety and efficacy of a humanized anti-human interleukin-6 (IL-6) receptor monoclonal antibody (MRA) in patients with MCD. We report here results of the first 60 weeks of the study enrolling 28 patients. The initial dosing period consisted of 8 infusions of 8 mg/kg MRA administered biweekly. Adjustments in the dose and treatment interval were allowed for each patient in an extension phase after 16 weeks. Within 16 weeks, treatment with MRA consistently alleviated lymphadenopathy and all the inflammatory parameters. Hemoglobin, albumin, and total cholesterol levels, high-density lipoprotein cholesterol values, and body mass index all increased significantly. In addition, fatigue diminished. Chronic inflammatory symptoms were successfully managed over 60 weeks. In 8 (28.6%) patients, the MRA dose was decreased or the treatment interval was extended without exacerbation. Eleven (73.3%) of 15 patients who had received oral corticosteroids before study entry were able to do well on a reduced corticosteroid dose. Most adverse events were mild to moderate in severity. MRA was tolerated well and significantly alleviated chronic inflammatory symptoms and wasting in patients with MCD.

Adult↗
PubMed2005

Usefulness of particle image analyzer for evaluation of fragmented red cells.

Quantitative determination of fragmented red cells (FRCs) in peripheral blood is useful in various clinical fields. We have previously reported an automatic detection method using a hematology analyzer essentially based on detection of small red cells. We then tried to use another instrument, the FPIA 2100, to reflect the characteristic morphology of red cells. As the circularity obtained by FPIA 2100 correlated with the FRC%, this type of instrument might be helpful to establish better automatic detection methods.

Cell Size↗
PubMed2005

Presence of somatic hypermutation and activation-induced cytidine deaminase in acute lymphoblastic leukemia L2 with t(14;18)(q32;q21).

AIM: Acute lymphoblastic leukemia (ALL) with L2 (FAB) morphology has rarely been reported to show t(14;18)(q32;q21). We aimed to delineate the stage at which this type of ALL is derived in B-lineage differentiation. METHODS: The somatic hypermutation (SHM) of the variable region of immunoglobulin heavy chain (IgV(H)) gene and the expression of terminal deoxynucleotidyl transferase (TdT), recombination-activating gene 1 and 2 (RAG-1 and -2), and activation-induced cytidine deaminase (AID) were investigated in three cell lines and two fresh samples, including a pair of matched fresh and cell line cells. RESULTS: TdT, RAG-1, and RAG-2 were variably expressed. AID was expressed in four of five samples. SHM of the IgV(H) gene was found in all samples with high average frequency (11.84%) comparable with that in follicular lymphoma. Ongoing mutation was seen in two fresh samples. CONCLUSION: As AID and SHM are generally regarded as properties exhibited by mature B cells, the presence of AID and SHM in this study seems to be incompatible with the general understanding of the early stage derivation of ALL in B-lineage differentiation. The results here give some insight into the relationship between disease type (ALL or lymphoma) and derivation stage, the overlapping of the early stage phenotype and the mature genomic characteristics, and the probable relationship between the mechanism of the occurrence of t(14;18)(q32;q21) and the machinery causing SHM.

Base Sequence↗