Search PubMed⌕ Search

Biomedical subjects

Shinichiro Okamoto

Publications and source records attributed to Shinichiro Okamoto.

At least 55 records · Page 3Linked to original sources
PubMed2004

Quantitative assessment of protein-bound tyrosine nitration in airway secretions from patients with inflammatory airway disease.

Because reactive nitrogen species (RNS) have potent inflammatory activity, they may be involved in the inflammatory process in pulmonary diseases. We recently reported increased numbers of 3-nitrotyrosine immunopositive cells, which are evidences of RNS production, in the sputum of patients with chronic obstructive pulmonary disease (COPD) and patients with asthma compared with healthy subjects. In the present study, we attempted to quantify this protein nitration in the airways by means of high-performance liquid chromatography (HPLC) used together with an electrochemical detection system that we developed. Sputum samples were obtained from 15 stable COPD patients, 9 asthmatic patients and 7 healthy subjects by using hypertonic saline inhalation. The values for the molar ratio of protein-bound 3-nitrotyrosine/tyrosine in patients with asthma (4.31 +/- 1.13 x 10(-6), p < 0.05) and patients with COPD (3.04 +/- 0.36 x 10(-6), p < 0.01) were significantly higher than those in healthy subjects (1.37 +/- 0.19 x 10(-6)). The levels of protein-bound 3-nitrotyrosine in the airways were not significantly different in asthmatic patients and COPD patients. A significant negative correlation was found between values for protein-bound 3-nitrotyrosine/tyrosine and % FEV1 values in patients with COPD (r = -0.53, p < 0.05) but not in patients with asthma. These results suggest that our HPLC-electrochemical method is useful for quantifying RNS production in human airways. More importantly, they show that increased RNS production in the airways seems to contribute in a critical way to the pathogenesis of COPD, and that the effects of RNS in airways may differ in asthma and COPD.

Aged↗
PubMed2004

Epstein-Barr virus-associated posttransplant lymphoproliferative disorder after a cord blood stem cell transplantation presenting with pulmonary nodules.

Sixteen months after a cord blood stem cell transplantation, a 6-year-old girl was diagnosed with Epstein-Barr virus-associated posttransplant lymphoproliferative disorder (EBV-PTLD). A CT scan revealed nodules in both lungs, but the patient had neither lymphadenopathy nor other lesions. The diagnosis was confirmed by histopathologic evaluation and the increased level of EBV DNA in the peripheral blood. The patient was successfully treated with rituximab, and a complete regression of the tumors was achieved. This case reveals the need to include EBV-PTLD in the differential diagnosis of pulmonary nodules, as well as demonstrating that rituximab may be effective treatment of EBV-PTLD after cord blood stem cell transplantation.

Antibodies, Monoclonal↗
PubMed2004

Thalidomide-induced severe neutropenia during treatment of multiple myeloma.

Recent reports have shown that thalidomide has antiangiogenic activity and is effective for the treatment of refractory multiple myeloma. Unlike other antineoplastic drugs, thalidomide is reported to rarely cause severe hematologic toxicity. In Keio University Hospital, 44 patients with refractory multiple myeloma, including 18 who had relapsed after hematopoietic stem cell transplantation, were treated with this drug as a single agent. Severe grade 3 or 4 neutropenia during thalidomide treatment was observed in 10 patients. This phenomenon was not noted in previous reports. Neutropenia usually occurred in the first or second week of treatment. Concomitant progression of thrombocytopenia occurred in 5 cases, and bone marrow hypoplasia without a significant increase in myeloma cell numbers was also observed in 5 cases. Neutropenia was not correlated with anti-tumor response or the plasma concentration of thalidomide but was more frequently observed in patients with a low neutrophil and platelet count, anemia, or a high plasma cell percentage in the bone marrow before thalidomide treatment. Thus, this drug should be used carefully for patients with pretreatment cytopenia or a high tumor burden in the bone marrow.

Adult↗
PubMed2004

Transformation of myelodysplastic syndrome to acute lymphoblastic leukemia: a case report and review of the literature.

Myelodysplastic syndrome (MDS) often transforms into acute leukemia, usually of a myeloid phenotype. However, the transformation of MDS into acute lymphoblastic leukemia (ALL) is extremely rare. We present a case of refractory anemia with excess of blasts (RAEB) that transformed into ALL. MDS (RAEB) was diagnosed in a 68-year-old Japanese woman in August 2001. Two months later, MDS progressed to erythroleukemia (French-American-British [FAB]classification, acute myeloid leukemia [AML]-M6), and in December, 2001, she was treated with combined chemotherapy containing aclarubicin, cytarabine, and granulocyte colony-stimulating factor, which improved her clinical symptoms. However, 1 month after the chemotherapy, she developed ALL. The blasts at that time had a markedly basophilic cytoplasm with multiple cytoplasmic vacuoles, and their morphology mimicked that of ALL-L3. The blasts also expressed CD13, a myeloid marker, in addition to lymphoid markers. Southern-blot analysis revealed rearrangement of the immunoglobulin heavy chain, but no additional chromosomal abnormality characteristic of ALL-L3 was detected. The patient was treated with chemotherapy, but she developed tumor lysis syndrome and died of multiple organ failure. Although the precise mechanism of lymphoid transformation is not yet fully understood, this case clinically supports the nature of MDS as a pluripotent hematopoietic stem cell disorder.

Aged↗
PubMed2004

Impact of cytogenetics on outcome of stem cell transplantation for acute myeloid leukemia in first remission: a large-scale retrospective analysis of data from the Japan Society for Hematopoietic Cell Transplantation.

On the basis of transplantation data from the Japan Society for Hematopoietic Cell Transplantation, we retrospectively analyzed the impact of cytogenetics at diagnosis on the outcome of transplantation in 628 patients with acute myeloid leukemia who underwent autologous (n = 200), allogeneic related (n = 363), or allogenic unrelated (n = 65) stem cell transplantation (SCT) at first complete remission. For autologous SCT, patients at good cytogenetic risk had a significantly lower relapse rate (P = .017) and a significantly higher event-free survival (EFS) (P = .013) compared with those at intermediate risk. For allogeneic SCT, patients at good cytogenetic risk had a significantly lower relapse rate (P = .019) and insignificantly higher EFS (P = .093) than those at poor risk. For unrelated SCT, there was no significant difference in relapse rate or EFS between patients at good risk and those at intermediate risk. Comparison of the 3 transplantation modalities revealed that autologous SCT patients had a significantly higher incidence of relapse compared with related or unrelated SCT patients in the intermediate-risk group but not in the good-risk group. However, there were no significant differences in EFS among the 3 transplant modalities in either of these 2 risk groups. In multivariate analysis, cytogenetics was found to be an independent predictor of relapse as well as of treatment failure.

Acute Disease↗
PubMed2004

[Successful bone marrow transplantation with a matched unrelated donor in an acute promyelocytic leukemia patient after reinduction therapy with arsenic trioxide].

A 44-year-old man with relapsed acute promyelocytic leukemia (APL), refractory to all-trans-retinoic acid (ATRA), daunorubicin, and cytosine arabinoside, was treated with arsenic trioxide (ATO). ATO was given intravenously at a dose of 0.15 mg/kg/day for 20 days, and the patient achieved complete remission. No serious adverse events related to ATO infusion were observed. He received ATO for 10 days as consolidation therapy and subsequently underwent HLA-matched unrelated donor stem cell transplantation. He remains in molecular remission 10 months after transplant. This case suggests that ATO could be a useful therapy prior to allogeneic stem cell transplantation in relapsed APL.

Adult↗
PubMed2004

[Interstitial pneumonia during treatment with thalidomide in a patient with multiple myeloma].

A 66-year-old man was referred to our hospital for the treatment of refractory multiple myeloma with thalidomide. He had a history of an interstitial pneumonia of unknown etiology two months before admission. Eight days after starting 200 mg/ day of thalidomide, he developed dyspnea and fever, followed by a macropapular rash in the trunk. The dyspnea got worse and a CT scan revealed interstitial pneumonia 16 days after the treatment. He required mechanical ventilatory support. Bronchoalveolar lavage fluid revealed eosinophilia, suggesting a thalidomide-induced interstitial pneumonia. Thalidomide was discontinued and methylprednisolone (1000 mg/d x 3 days) was started, and the pneumonia and rash markedly improved within six days. After that the patient contracted MRSA pneumonia and died of MRSA septicemia.

Aged↗
PubMed2003

Allogeneic hematopoietic stem cell transplantation from family members other than HLA-identical siblings over the last decade (1991-2000).

The reported outcome of hematopoietic stem cell transplantation (HSCT) from HLA-mismatched family members has been inconsistent. The object of this study was to evaluate the true impact of HLA-mismatch by using recent data from a homogenous population, excluding HSCT procedures that used graft manipulations, and by considering genotypic matching. Clinical data of 2947 patients who underwent allogeneic HSCT for leukemia or myelodysplastic syndrome were extracted from the database of the Japan Society for Hematopoietic Cell Transplantation. The main outcome measures were survival and the incidence of graft-versus-host disease (GVHD). The presence of serologic HLA-mismatch, higher age, and high-risk disease were identified as independent risk factors for both shorter survival and the development of grade III to IV acute GVHD. The impact of HLA-mismatch on survival was more relevant in standard-risk patients. These findings persisted when we used genotypic HLA matching. Survival after one-locus-mismatched HSCT was equivalent to that after HLA-matched unrelated HSCT. We concluded that when a one-locus-mismatched family donor is available for high-risk patients, immediate HSCT using this donor is warranted. In standard-risk patients, however, survival after one-locus-mismatched HSCT is significantly shorter than that after HLA-matched HSCT, and the indications for HSCT should be considered carefully.

Acute Disease↗
PubMed2003

8-nitroguanosine formation in viral pneumonia and its implication for pathogenesis.

For many diseases, mediation of pathogenesis by nitric oxide (NO) has been suggested. In this study, we explored NO-induced viral pathogenesis with a focus on nucleic acid damage as evidenced by 8-nitroguanosine formation in vivo. Wild-type mice and littermate mice deficient in inducible NO synthase (iNOS) were infected with influenza or Sendai virus. Formation of 8-nitroguanosine in virus-infected lungs was assessed immunohistochemically with an antibody specific for 8-nitroguanosine. Extensive nitration of RNA either treated with peroxynitrite or obtained from cultured RAW 264 cells expressing iNOS was readily detected by this antibody. Strong 8-nitroguanosine immunostaining was evident primarily in the cytosol of bronchial and bronchiolar epithelial cells of virus-infected wild-type mice but not iNOS-deficient mice. This staining colocalized with iNOS immunostaining in the lung. 8- Nitroguanosine staining disappeared after addition of exogenous authentic 8-nitroguanosine during the antibody reaction and after pretreatment of tissues with sodium hydrosulfite, which reduces 8-nitroguanosine to 8-aminoguanosine. NO was generated in excess in lungs of wild-type mice but was eliminated in iNOS-deficient mice after virus infection; this result also correlated well with formation of 8-nitroguanosine and 3-nitrotyrosine. One consequence of the lack of iNOS expression was marked improvement in histopathological changes in the lung and the lethality of the infection without effects on cytokine responses and viral clearance. It is intriguing that 8-nitroguanosine markedly stimulated superoxide generation from cytochrome P450 reductase and iNOS in vitro. The present data constitute a demonstration of 8-nitroguanosine formation in vivo and suggest a potential role for NO-induced nitrative stress in viral pathogenesis.

Animals↗
PubMed2003

Granisetron plus dexamethasone versus granisetron alone in the prevention of vomiting induced by conditioning for stem cell transplantation: a prospective randomized study.

This prospective randomized study compared the efficacy and toxicity of granisetron and dexamethasone to those of granisetron alone for antiemetic control in patients receiving high-dose chemotherapy with or without total body irradiation (TBI) for stem cell transplantation. Patients were divided randomly into 2 groups. Groups received granisetron twice daily at a dose of 40 microg/kg with or without 4 mg dexamethasone (GS group and G group, respectively), starting 30 minutes before each dose of chemotherapeutic agent or TBI, or 12 hours after the first dose if TBI or a drug was given once a day. Fifty patients were evaluated for the analysis. During the first 24 hours of conditioning, 23 of 25 patients (92.0%) in the GS group achieved complete control of emesis (no emetic episodes over the course of a day), compared with 72.0% in the G group (P = .06). For patients receiving TBI on the first day of conditioning, complete emetic control was achieved in all patients (100.0%) in the GS group, compared with 63.2% in the G group (P = .02). The same degree of emetic control was maintained throughout the conditioning period in 38.8% of the GS group and 29.9% of the G group (P = .10). Adverse reactions were observed more frequently in the GS group (68.0% versus 5.0% in the G group). These reactions included insomnia, headache, flushing, and hyperglycemia. None of the events were serious. We conclude that granisetron with dexamethasone seems superior to granisetron alone for the prevention of emesis resulting from the conditioning regimen; however, the more frequent side effects may limit the wide use of this combination.

Adolescent↗
PubMed2003

Ex vivo manipulation of umbilical cord blood-derived hematopoietic stem/progenitor cells with recombinant human stem cell factor can up-regulate levels of homing-essential molecules to increase their transmigratory potential.

OBJECTIVE: The cause of delayed hematopoietic reconstitution after umbilical cord blood transplantation (UCBT) remains controversial. We hypothesized that hematopoietic stem/progenitor cells (HS/PCs) from UCB have some defects of the homing-related molecules responsible for their slow engraftment. MATERIALS AND METHODS: A homing-related molecule repertoire expressed on HS/PCs from fresh and cryopreserved UCB, mobilized peripheral blood (mPB), and bone marrow (BM) were compared using sensitive, four-color fluorescence-activated cell sorting analysis. Purified CD34+ cells were subjected to ex vivo transmigration through double-coated transwell filter inserts, and an in vivo homing assay was performed in xenotransplanted NOD/SCID mice. RESULTS: UCB-derived CD34(bright) cells expressed significantly lower levels of CD49e, CD49f, and CXCR-4 than their mPB and BM counterparts. CD34+ cells from UCB (and BM) exhibited significantly lower ex vivo transmigration than those from mPB, which were largely blocked by neutralizing antibodies to CD49e or CD49f. Recombinant human tumor necrosis factor-alpha treatment enhanced ex vivo transmigration of CD34+ cells from UCB and BM by inducing expression of the matrix metalloproteinases MMP-2/MMP-9. Short-term treatment of UCB-derived CD34+ cells with rHu-stem cell factor (rHuSCF) up-regulated levels of the homing-related molecules with their increased ex vivo transmigratory and in vivo homing potential. CONCLUSION: Our results indicate that disadvantageous transmigratory behavior of HS/PCs from UCB, which might partly explain the delayed reconstitution after UCBT, can be reversed by ex vivo manipulation with rHuSCF.

Animals↗
PubMed2003

Periductal area as the primary site for T-cell activation in lacrimal gland chronic graft-versus-host disease.

PURPOSE: To examine immune processes in the lacrimal gland of patients with chronic graft-versus-host disease (cGVHD) by evaluating the expression of surface molecules associated with T-cell activation. METHODS: Antibodies to CD4, CD8, CD34, CD40, CD54, CD80, CD86, CD154, and HLA-DR were used for immunohistochemical analysis of lacrimal gland biopsy specimens obtained from nine patients with cGVHD and five with Sjögren's syndrome (SS). The regions of interest were further assessed by transmission electron microscopy. RESULTS: CD4(+) and CD8(+) T cells were mainly detected in the periductal areas of the glands of patients with cGVHD, but were distributed throughout the acinar areas in patients with SS. In the periductal areas of patients with cGVHD, a subpopulation of CD4(+) and CD8(+) T cells expressed the activation marker CD154. In addition, CD4(+) and CD8(+) T cells were colocalized with mononuclear infiltrates and stromal fibroblasts expressing the full component of surface molecules necessary for antigen presentation, including HLA-DR, CD54, CD40, CD80, and CD86. Electron microscopy revealed activated fibroblasts that embraced lymphocytes and macrophages with their processes. Also, there were more CD8(+) T cells in the glandular epithelia of patients with cGVHD than in those with SS. Intraepithelial T cells were attached to epithelial cells by several primitive contacts and colocalized with dead cells. CONCLUSIONS: The results strongly suggest that CD4(+) and CD8(+) T cells in the lacrimal glands of patients with cGVHD are primarily activated in the periductal area through antigenic stimulation by potent antigen-presenting cells and stromal fibroblasts, and exert various effector functions, including cytotoxic effects on glandular epithelial cells.

Adult↗