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Toshiki Yamada

Publications and source records attributed to Toshiki Yamada.

At least 19 recordsLinked to original sources
PubMed2006

Frog ANP increases the amiloride-sensitive Na(+) channel activity in urinary bladder cells of Japanese tree frog, Hyla japonica.

We examined the mechanism of amiloride-sensitive Na(+) channels (ENaC) activated by fANP in epithelial cells of frog urinary bladder by using a cell-attached patch-clamp technique. ENaC activities in the epithelial cells were significantly increased following administration of both 10(-9)M fANP and 10(-5)M 8-Br-cGMP. Both fANP and 8-Br-cGMP, however, failed to activate the ENaC in the presence of 10(-6)M amiloride. In addition, 8-Br-cGMP failed to activate the ENaC in the presence of a PKA inhibitor, KT-5720. In the next experiment, we measured both cGMP and cAMP production levels after treatment of fANP on the frog urinary bladder cells. Frog ANP significantly increased cGMP production, but not the cAMP production. Taken together, these results suggest that fANP activates ENaC through increases in cGMP production and activation of PKA.

Animals↗
PubMed2006

Serum-soluble tumor necrosis factor receptor 2 (sTNF-R2) level determines clinical outcome in patients with aggressive non-Hodgkin's lymphoma.

BACKGROUND: Recently investigators have worked to identify prognostic factors in non-Hodgkin's lymphoma (NHL) so an appropriate therapeutic plan can be put in action. The aim of the present study was to assess the prognostic significance of serum soluble tumor necrosis factor receptor (sTNF-R) 2 in aggressive NHL. METHODS: One hundred and ten consecutive patients with aggressive NHL who were previously untreated (diffuse large B-cell lymphoma; 94, peripheral T-cell lymphoma; 16) were prospectively enrolled in this study between 1997 and 2002. The patients were treated with 6-8 cycles of CHOP or THP-COP regimens. RESULTS: High serum sTNF-Rs level was associated with some poor prognostic factors and low complete remission rate. Patients with high sTNF-R1 (4 ng/mL and over) and sTNF-R2 (15 ng/mL and over) at onset had significantly lower survival rates (5 yr: 19%, 19%) than those with low sTNF-R1 (under 4 ng/mL) and sTNF-R2 (under 15 ng/mL) (62% and 69%), respectively (P < 0.0005 and 0.0001). Multivariate analysis employing sTNF-R2 and some conventional prognostic factors demonstrated that a combination of sTNF-R2 and performance status, and that of sTNF-R2, sIL-2R, and LDH were significant prognostic factors for poor overall survival and for poor event-free survival, respectively. In addition, we attempted to use sTNF-R2 in combination with the international prognostic index (IPI). The patients in the high risk group and those with high sTNF-R2 in the low-intermediate (LI)/high-intermediate (HI) risk group had significantly lower survival rates than the patients in the low risk group and those with low sTNF-R2 in LI/HI risk group (P < 0.0001). CONCLUSIONS: The results suggest that a high serum sTNF-R2 level predicts a poor prognosis in aggressive NHL and may be a useful biomarker for selecting appropriate treatment when used in combination with the IPI.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Binary clusters AuPt and Au6Pt: structure and reactivity within density functional theory.

Within density functional theory with the general gradient approximation for the exchange and correlation, the bimetallic clusters AuPt and Au(6)Pt have been studied for their structure and reactivity. The bond strength of AuPt lies between those of Au(2) and Pt(2), and it is closer to that of Au(2). The Pt atom is the reactive center in both AuPt and AuPt(+) according to electronic structure analysis. AuPt(+) is more stable than AuPt. Au(6)Pt prefers electronic states with low multiplicity. The most stable conformation of Au(6)Pt is a singlet and has quasi-planar hexagonal frame with Pt lying at the hexagonal center. The doping of Pt in Au cluster enhances the chemical regioselectivity of the Au cluster. The Pt atom essentially serves as electron donor and the Au atoms bonded to the Pt atom acts as electron acceptor in Au(6)Pt. The lowest triplet of edge-capped rhombus Au(6)Pt clusters is readily accessible with very small singlet-triplet energy gap (0.32 eV). O(2) prefers to adsorb on Au and CO prefers to adsorb on Pt. O(2) and CO have stronger adsorption on AuPt than they do on Au(6)Pt. CO has a much stronger adsorption on AuPt bimetallic cluster than O(2) does. The adsorption of CO on Pt modifies the geometry of AuPt bimetallic clusters.

Journal Article↗
PubMed2006

Fas and Fas ligand expression on germinal center type-diffuse large B-cell lymphoma is associated with the clinical outcome.

In recent years, diffuse large B-cell lymphoma (DLBCL) has been classified by DNA microarray analysis into the germinal center B-cell-like (GC) type, the activated B-cell-like (ABC) type and type 3. The latter two types can be collectively categorized as the non-GC (NGC) type. From the prognostic perspective, the GC type has a favorable clinical outcome when compared with the NGC type. The protein Fas induces apoptosis of lymphocytes by binding with the Fas ligand (FasL), and escape from such apoptosis is considered to lead to malignant transformation of the cells and unrestricted growth of lymphoma. We proposed a hypothesis that Fas/FasL expression could be possibly related with a better survival of GC type DLBCL and evaluated 69 DLBCL cases immunohistochemically with CD10, Bcl-6, MUM1, Fas and FasL. These lymphomas were classified as GC type (positive for CD10 or Bcl-6 and negative for MUM1) or NGC type. The GC type had a better overall survival rate than the NGC type (P = 0.0723). Among markers as given above, positive CD10 was the most significant prognostic factor for overall survival in total DLBCL (P < 0.05). In the GC type, Fas and FasL expressions were significantly associated with a favorable overall survival (Fas: P < 0.005; FasL: P < 0.05). Hence, Fas or FasL expression might contribute to a better prognosis of this type of DLBCL.

Adult↗
PubMed2006

Early-onset thyrotoxicosis after unrelated cord blood transplantation for acute myelogenous leukemia.

Thyroid dysfunction is a common complication after allogeneic hematopoietic stem cell transplantation (SCT). However, thyrotoxicosis as defined by elevated serum-free thyroxine (FT4) or free triiodothyronine (FT3) levels together with low thyroid-stimulating hormone (TSH) levels is rare after SCT. Here we describe 2 patients who developed thyrotoxicosis within the first 50 days after unrelated cord blood transplantation (CBT). Patient 1 is a 32-year-old woman with acute myelogenous leukemia (AML)-M5a who underwent CBT. On day +41, she developed tachycardia. On day +48, FT4 increased to 2.2 ng/dL and TSH was suppressed to less than 0.1 microU/mL. Antithyroid peroxidase antibody was positive. On day +83, FT4 spontaneously decreased to 1.4 ng/dL. Patient 2 is a 42-year-old man with AML-M4 who underwent CBT. On day +42, he developed tachycardia. On day +48, FT3 increased to 4.75 pg/mL and TSH was suppressed to 0.02 microU/mL. Antithyroid peroxidase antibody was positive. Eight months after CBT, his thyroid function spontaneously returned to normal. The presence of antithyroid peroxidase antibody suggested that immune-mediated reactions might be associated with the development of thyrotoxicosis after CBT in our patients. The present study shows that thyrotoxicosis can occur during very early periods after CBT.

Adult↗
PubMed2005

Atrial natriuretic peptide and cGMP activate sodium transport through PKA-dependent pathway in the urinary bladder of the Japanese tree frog.

The effects of atrial natriuretic peptide (ANP) and cGMP on transepithelial ion transport were examined in the urinary bladder of the Japanese tree frog, Hyla japonica, using Ussing chamber voltage-clamp and whole-cell patch-clamp techniques. When the bladders were exposed to 4.4 x 10(-11) to 10(-6) M ANP or 10(-7) to 3 x 10(-4) M 8-Br-cGMP, both the transepithelial potential difference (PD) and the short-circuit current (Isc) were significantly increased in a concentration-response manner. The cGMP-dependent responses were inhibited in a Na+-free bath solution and in the presence of amiloride. The cGMP-dependent increases in Isc were significantly inhibited by specific PKA inhibitors (5 x 10(-7) M KT-5720 and >10(-5) M H-89), but not by a specific PKG inhibitor (5 x 10(-7) M KT-5823). ANP-dependent increases in Isc were also significantly inhibited by KT-5720. In the patch-clamp study, ANP and cGMP significantly increased in inward currents involving Na+ uptake. These results suggest that a cross-talk mechanism exists between cAMP and cGMP signaling pathways, which leads to Na+ transport in the frog urinary bladder. In addition, the cGMP-dependent increases in Isc were partially inhibited by 10(-4) M l-cis-diltiazem, a specific inhibitor of cyclic nucleotide-gated (CNG) channels. These results also suggest a relation between CNG channels and the cGMP-dependent increases in Na+ absorption of the frog urinary bladder.

Animals↗
PubMed2005

Deposition of thermally unstable molecules with the spray-jet technique on Au(111) surface.

A porphyrin derivative (5,15-bis(4-ethynylphenyl)-10,20-bis(3,5-di-tert-butylphenyl)porphyrin: trans-BETBPP) possessing chemically reactive substituents was successfully deposited on an Au(111) surface with a new molecular beam deposition system with use of a spray-jet technique (Spray-jet-MBD) without denaturing the molecules. The deposited molecular overlayers were observed at 77 K under ultrahigh vacuum condition by scanning tunneling microscopy (STM). They form two different overlayer structures: a linear arrangement and a square lattice structure. In these overlayers, some molecules were accidentally moved by STM tip agitation, which indicates that the molecules were not polymerized during the deposition process.

Journal Article↗
PubMed2005

High-resolution scanning tunneling microscopy images of molecular overlayers prepared by a new molecular beam deposition apparatus with spray-jet technique.

We developed a new molecular beam deposition apparatus using a spray-jet technique for high-quality thin film preparation of nonsublimable molecules. The apparatus was used to deposit chloro[tri-tert-butyl-subphthalocyaninato]boron(III) (TBSubPc) molecules on an Au(111) surface for analysis by low-temperature scanning tunneling microscopy (STM). Highly resolved images, in which tert-butyl groups in a TBSubPc molecule were clearly identifiable, were obtained. The image quality and the resolution of these images compared favorably well to STM images taken on reference samples which were sublimed onto Au (111) from a heated crucible.

Journal Article↗
PubMed2005

Prevalence of hepatitis B and C virus infection in haematological malignancies and liver injury following chemotherapy.

The aim of this study was to determine the carrier rate of hepatitis virus in patients with haematological malignancies and the incidence of liver injury in these patients following chemotherapy. From January 1996 to September 2002, we studied 601 consecutive, unselected series of patients with haematological malignancies admitted in our hospital unit (Japan). They consisted of 246 cases of acute leukaemia, 218 non-Hodgkin's lymphoma (NHL), 13 adult T-cell leukaemia, and 124 multiple myeloma. Of these 601 patients, 373 were men and 228 were women; their mean age was 61 yr, with a range from 18 to 89 yr. The prevalences of hepatitis B virus (HBV) and hepatitis C virus (HCV) were 7.3% and 10.1%, respectively, in NHL, both higher than those in acute leukaemia (1.7% and 2.9%, P < 0.005) and in general Japanese population (1.2% and 2.6%). The incidence of post-chemotherapy liver injury in 25 HBV carriers (36.0%) was significantly higher than that in 539 non-hepatitis virus carriers (12.6%, P = 0.003) and 37 HCV carriers (10.8%, P = 0.026). Liver injury in HBV carriers was more often present in patients who had been treated with steroids than in those without steroids (72.7% and 0%, P = 0.013). After lamivudine became available in our institution, the incidence of liver injury in HBV carriers was reduced from 53.3% to 10.0% (P = 0.041). The therapeutic strategy for haematological malignancies in hepatitis virus carriers should be further investigated.

Adolescent↗
PubMed2005

Low-dose granulocyte colony-stimulating factor overcomes neutropenia in the treatment of non-Hodgkin's lymphoma with higher cost-effectiveness.

To facilitate more economical medical care, we carried out a prospective study of whether a THP-COP regimen (cyclophosphamide, pirarubicin, vincristine, and prednisolone) with low-dose granulocyte colony-stimulating factor (G-CSF) would effectively treat non-Hodgkin's lymphoma (NHL). From April 2003 through March 2004, we enrolled 19 consecutive patients with newly diagnosed NHL treated at our hospital. The patients were divided into young and elderly groups. Each patient underwent chemotherapy with 8 courses of a THP-COP regimen with a 50-microg dose of lenograstim. Age- and sex-matched historical control patients (n = 141) received NHL diagnoses between 1998 and 2003. Each patient in the control group underwent the same chemotherapy and received a 100-microg dose of lenograstim. The mean (+/-SD) total amounts of G-CSF per cycle of chemotherapy were 332 +/- 103 microg (young patients) and 345 +/- 128 microg (elderly patients) in the low-dose group and 594 +/- 439 microg (young) and 730 +/- 551 microg (elderly) in the control group. The duration of fever in 1 cycle of chemotherapy was 0.3 +/- 1.0 days (young) and 0.1 +/- 0.8 days (elderly) in the low-dose group and 0.5 +/- 1.3 days (young) and 0.8 +/- 2.0 days (elderly) in the control group. A THP-COP regimen with low-dose G-CSF could be administered to NHL patients with safety. Administration of a 50-microg dose of lenograstim is sufficient and recommended for the treatment of NHL.

Adjuvants, Immunologic↗
PubMed2005

[Myelodysplastic syndrome with der (1;7) transformed from aplastic anemia 42 years after onset].

A 51-year-old man had been diagnosed with severe aplastic anemia (AA) at the age of 9 years. He was treated with occasional transfusions for the next 35 years. Following initiation of cyclosporin A (CsA), the patient became transfusion-independent at 44-years-old. Anemia improved after cessation of CsA and no therapy was required for the next 5 years. However, severe pancytopenia suddenly developed at the age of 51. Bone marrow aspiration revealed myelodysplastic syndrome (MDS) with der (1;7). The ineffectiveness of CsA for MDS led to resumed dependence on transfusion. This case suggests that the appearance of MDS clones might have contributed to transient hematological improvement. Bone marrow aspiration should be considered in patients with AA if unexpected hematological improvement appears.

Anemia, Aplastic↗
PubMed2004

Serum-soluble interleukin-2 receptor (sIL-2R) level determines clinical outcome in patients with aggressive non-Hodgkin's lymphoma: in combination with the International Prognostic Index.

PURPOSE: The aim of the present study was to assess the prognostic significance of serum soluble interleukin-2 receptor (sIL-2R) in aggressive non-Hodgkin's lymphoma (NHL). METHODS: One hundred and thirteen consecutive patients with previously untreated aggressive NHL (diffuse large B-cell lymphoma, 96; peripheral T-cell lymphoma, 17) prospectively participated in this study between 1995 and 2001. The patients were treated with 6-8 cycles of a CHOP or THP (pirarubicin)-COP regimen. RESULTS: A high serum sIL-2R level (2,000 U/ml and over) at onset was associated with a low complete remission rate. Patients with high sIL-2R had significantly lower survival rates (5-year, 24%) than those with low sIL-2R (under 2,000 U/ml) (74%) (P<0.01). Multivariate analysis employing sIL-2R levels and conventional prognostic factors demonstrated that high sIL-2R, presence of B-symptoms, and advanced age (60 years and older) were significantly unfavorable variables for overall survival. In addition, we attempted to use sIL-2R in combination with the International Prognostic Index (IPI). The patients in the high (H) risk group and those with high sIL-2R in the low-intermediate (LI)/high-intermediate (HI) risk group had significantly lower survival rates than the patients in the low (L) risk group and those with low sIL-2R in the LI/HI risk group (P<0.001). CONCLUSION: The results suggest that a high serum sIL-2R level predicts a poor prognosis in aggressive NHL and may be a useful biomarker for selecting appropriate treatment when used in combination with the IPI.

Age Factors↗
PubMed2004

Single-institute comparative analysis of unrelated bone marrow transplantation and cord blood transplantation for adult patients with hematologic malignancies.

Unrelated cord blood transplantation (CBT) has now become more common, but as yet there have been only a few reports on its outcome compared with bone marrow transplantation (BMT), especially for adults. We studied the clinical outcomes of 113 adult patients with hematologic malignancies who received unrelated BM transplants (n = 45) or unrelated CB transplants (n = 68). We analyzed the hematopoietic recovery, rates of graft-versus-host disease (GVHD), risks of transplantation-related mortality (TRM) and relapse, and disease-free survival (DFS) using Cox proportional hazards models. The time from donor search to transplantation was significantly shorter among CB transplant recipients (median, 2 months) than BM transplant recipients (median, 11 months; P < .01). Multivariate analysis demonstrated slow neutrophil (P < .01) and platelet (P < .01) recoveries in CBT patients compared with BMT patients. Despite rapid tapering of immunosuppressants after transplantation and infrequent use of steroids to treat severe acute GVHD, there were no GVHD-related deaths among CB transplant recipients compared with 10 deaths of 24 among BM transplant recipients. Unrelated CBT showed better TRM and DFS results compared with BMT (P = .02 and P < .01, respectively), despite the higher human leukocyte antigen mismatching rate and lower number of infused cells. These data strongly suggest that CBT could be safely and effectively used for adult patients with hematologic malignancies.

Adolescent↗
PubMed2004

Ganciclovir-related neutropenia after preemptive therapy for cytomegalovirus infection: comparison between cord blood and bone marrow transplantation.

We studied ganciclovir (GCV)-related neutropenia after preemptive therapy for cytomegalovirus infection: 9 of 17 (53%) cord blood transplantation (CBT) patients and 18 of 20 (90%) bone marrow transplantation (BMT) patients developed GCV-related neutropenia with an absolute neutrophil count (ANC) of less than 1,000/microl. Among the patients who did not receive granulocyte colony-stimulating factor, 2 (13%) and 1 (7%) CBT patients, and 10 (56%) and 8 (44%) BMT patients, developed neutropenia with an ANC of less than 500 and 250/microl, respectively. The incidences of neutropenia in patients with an ANC of less than 1,000, 500, and 250/microl were significantly lower after CBT in comparison with BMT. Two BMT patients, but no CBT patients, developed neutropenic fever, and both patients recovered after antibiotic therapy. In CBT patients, a creatinine clearance rate of less than 50 ml/min and an absence of steroid therapy were associated with a greater incidence of GCV-related neutropenia. No risk factors for GCV-related neutropenia were found in BMT patients. These results suggest that GCV may be less toxic to myeloid progenitor cells from cord blood than those from bone marrow.

Adolescent↗
PubMed2004

Unrelated cord blood transplantation with a reduced-intensity conditioning regimen following autologous transplantation for multiple myeloma.

Two patients, 51- and 45-year-old men with stage III immunoglobulin G multiple myeloma, achieved partial and complete remissions, respectively, after conventional chemotherapy. They both received high-dose melphalan (200 mg/m2) with autologous stem cell transplantation (ASCT). Eighty-four and 78 days after ASCT, the patients underwent unrelated cord blood transplantation (CBT) following treatment with total-body irradiation (2 Gy), fludarabine (90 mg/m2), and melphalan (140 mg/m2). Neutrophil engraftment was attained on day +27 in patient 1 and day +15 in patient 2. Full donor chimerism of the marrow cells was confirmed. Regimen-related toxicity in both patients remained within grade I. Grades I and II acute graft-versus-host disease (GVHD) occurred in patients I and 2, respectively, but improved without steroid therapy. Both patients developed limited chronic GVHD of the skin but needed no treatment. The serum paraprotein level in patient 1 decreased further after ASCT and CBT but remained at minimally detectable levels. The serum and urine paraprotein levels in patient 2 remained below detectable limits. These results suggested that CBT with a reduced-intensity conditioning regimen after high-dose chemotherapy with ASCT is a new promising approach for the treatment of multiple myeloma.

Cord Blood Stem Cell Transplantation↗
PubMed2003

Biweekly CHOP or THP-COP regimens in the treatment of newly diagnosed aggressive non-Hodgkin's lymphoma. A comparison of doxorubicin and pirarubicin: a randomized phase II study.

PURPOSE: To compare the efficacy and safety of a biweekly CHOP regimen consisting of cyclophosphamide (CPA), doxorubicin (DOX), vincristine (VCR), and prednisolone (PSL) and those of a biweekly THP-COP regimen containing pirarubicin (THP), an anthracyclin with less cardiotoxicity than DOX. METHODS: A prospective, randomized phase II study with 80 patients (40 receiving CHOP or THP-COP) less than 70 years of age with previously untreated aggressive non-Hodgkin's lymphoma (NHL). The regimens consisted of DOX or THP 50 mg/m2, CPA 750 mg/m2, VCR 1.4 mg/m2, and PSL 100 mg/body administered for 5 days every 2 weeks for eight cycles. RESULTS: No significant differences in known prognostic factors were found between the two groups. Complete remission rate was 72.5% (72.5% for CHOP, 72.5% for THP-COP). The 5-year overall survival rate was 49.2% (43.7% for CHOP, 54.0% for THP-COP). When the patients were divided into groups with favorable or poor prognostic factors according to the International Prognostic Index, survival of the former group (L/LI) was superior to that of the later group (HI/H), regardless of chemotherapy regimen ( P < 0.001). Although grade 3 cardiotoxicity occurred in one patient in the CHOP group, no fatal toxic reactions occurred in either group. The THP-COP produced results equivalent to those of CHOP regarding efficacy and safety in aggressive NHL patients less than 70 years of age. CONCLUSIONS: Although both regimens effectively treated those patients with favorable prognostic factors, neither was satisfactory for treating those with poor prognostic factors.

Aged↗