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Biomedical subjects

A Togawa

Publications and source records attributed to A Togawa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Identification and localization of two brefeldin A-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors in a macromolecular complex.

Two brefeldin A (BFA)-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors, 200-kDa BIG1 and 190-kDa BIG2, were copurified from bovine brain cytosol associated with >670-kDa macromolecular complexes. When observed by immunofluorescence in HeLa S3 and HepG2 cells, endogenous BIG1 and coexpressed BIG2 were distributed in a punctate pattern throughout the cytosol, and also concentrated in the perinuclear region, where endogenous BIG1 and BIG2 each partially colocalized with Golgi-specific 58K protein and gamma-adaptin. On Western blot analysis, both BIG1 and BIG2 were clearly more abundant in the cytosol than in the microsomal fractions. After density gradient centrifugation of a microsomal fraction, BIG1 and BIG2 were recovered in the same fraction as beta-COP, a marker for Golgi membranes. When cytosol from HeLa S3 cells was subjected to gel filtration and fractions were analyzed by Western blotting, the largest percentages of both BIG1 and BIG2 were detected in fractions containing proteins with a molecular mass of >670 kDa. Western blotting using anti-peptide antibodies specific for BIG1 or BIG2 demonstrated that approximately 70% of BIG2 was immunoprecipitated along with 100% of BIG1 by the anti-BIG1 IgG, and approximately 75% of BIG1 was coprecipitated with 100% of BIG2 by the anti-BIG2 IgG. All observations were consistent with the conclusion that significant fractions of BIG1 and BIG2 exist as components of the same macromolecular complexes in bovine brain cytosol and are similarly localized in cultured cells.

ADP-Ribosylation Factors↗
PubMed2000

Similarities in function and gene structure of cytohesin-4 and cytohesin-1, guanine nucleotide-exchange proteins for ADP-ribosylation factors.

Activation of ADP-ribosylation factors (ARFs), approximately 20-kDa GTPases that are inactive in the GDP-bound form, depends on guanine nucleotide-exchange proteins (GEPs) to accelerate GTP binding. A novel ARF GEP, designated cytohesin-4, was cloned from a human brain cDNA library. Deduced amino acid sequence of the 47-kDa protein contains the same structural components present in cytohesin -1, -2, and -3, including an approximately 200-amino acid Sec7 domain with an approximately 100-residue pleckstrin homology domain near the C terminus. The Sec7 domain sequence is 77% identical to those of other cytohesins. Structures of the cytohesin-4 and cytohesin-1 genes were remarkably similar, except for an extra 3-base pair (GAG) exon present in cytohesin-1. Two mRNAs with and without the 3-base pair sequence were found in brain in different ratios for cytohesin-1, -2, and -3 but not cytohesin-4. Recombinant cytohesin-4 stimulated guanosine 5'-3-O-(thio)triphosphate binding by human ARF1 and ARF5 but not ARF6. Like other cytohesins and unlike the approximately 200-kDa ARF GEPs, it was not inhibited by brefeldin A. A cytohesin-4 mRNA of approximately 3.7 kilobases, abundant in leukocytes, was not detected in most tissues. Among separated populations of blood cells, approximately 90% of CD33(+) (monocytes), 80% of CD2(+) (NK/T), and 10-20% of CD19(+) (B) cells contained cytohesin-4 mRNA by in situ hybridization. Thus, in gene structure and brefeldin A-insensitive GEP activity, cytohesin-4 resembles other cytohesins, but its tissue distribution differs considerably, consistent with a different specific function.

ADP-Ribosylation Factors↗
PubMed2000

High serum lactate dehydrogenase level predicts short survival after vincristine-doxorubicin-dexamethasone (VAD) salvage for refractory multiple myeloma.

We evaluated possible prognostic factors just before salvage therapy with vincristine, doxorubicin, and dexamethasone (VAD) for 36 patients with refractory multiple myeloma. The median duration from diagnosis to the first VAD salvage was 14 months (range 2-76 months). Among parameters that have been shown to be associated with poor survival, a high serum lactate dehydrogenase (LDH) level was the sole significant predictor of survival. The median survival of patients with high LDH levels was 4 months, whereas that of patients with low LDH levels was 20 months. A multivariate analysis identified high LDH and high age as independent prognostic factors. More aggressive therapies might be indicated for high-LDH patients with refractory myeloma.

Adult↗
PubMed2000

Enhancement of poly-adenosine diphosphate-ribosylation in human hepatocellular carcinoma.

BACKGROUND: Poly-adenosine diphosphate (ADP)-ribosylation, catalysed by poly(ADP-ribose) polymerase (PARP), is a post-translational modification of nuclear proteins and is involved in a wide range of biological processes including DNA repair, cell proliferation and malignant transformation. Alteration of this reaction in human hepatocellular carcinoma (HCC) is of interest, but has not yet been explored. The aim of this study was to evaluate poly-ADP-ribosylation and to compare the expression of PARP in HCC and adjacent non-tumour tissues. METHODS: Tumorous and adjacent non-tumorous tissues were obtained from five consecutive patients with HCC during surgery for tumour resection. Tissue homogenates were subjected to ADP-ribosylation with [32P]-nicotinamide adenine dinucleotide. The ADP-ribosylated proteins were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis, followed by autoradiography. Expression of PARP was also evaluated by western blotting. RESULTS: Several proteins were ADP-ribosylated in human HCC tissues. Notably, the radiolabelling of a 116-kDa protein was remarkably greater than that in adjacent non-tumorous tissues (86.5 +/- 35.2 arbitrary units by densitometry vs 12.2 +/- 9.9, mean +/- SD, n = 5, P < 0.02). The radiolabelling of the 116-kDa protein was decreased in the presence of PARP inhibitors in a concentration-dependent manner. Immunoblot analyses revealed that the radiolabelled protein was PARP and that its expression was significantly greater in HCC than in adjacent non-tumorous tissues (333 +/- 204% of non-tumorous tissue, P < 0.05). CONCLUSIONS: We found that poly-ADP-ribosylation and PARP expression were significantly increased in human HCC compared with those in adjacent non-tumorous tissues in surgically obtained specimens.

ADP-Ribosylation Factors↗
PubMed2000

Involvement of a small GTP-binding protein (G protein) regulator, small G protein GDP dissociation stimulator, in antiapoptotic cell survival signaling.

Small GTP-binding protein GDP dissociation stimulator (Smg GDS) regulates GDP/GTP exchange reaction of Ki-Ras and the Rho and Rap1 family members and inhibits their binding to membranes. In fibroblasts, Smg GDS shows mitogenic and transforming activities in cooperation with Ki-Ras. However, the physiological function of Smg GDS remains unknown. Here we show that mice lacking Smg GDS died of heart failure shortly after birth, not resulting from developmental heart defects but from enhanced apoptosis of cardiomyocytes triggered by cardiovascular overload. Furthermore, neonatal thymocytes and developing neuronal cells underwent apoptotic cell death. Smg GDS-/- thymocytes were susceptible to apoptotic inducers, such as etoposide and UV irradiation. Smg GDS-/- thymocytes were protected from etoposide-induced cell death by ex vivo transduction of the Smg GDS cDNA. These phenotypes partly coincide with those observed in Ki-Ras-deficient mice, suggesting that Smg GDS is involved in antiapoptotic cell survival signaling through Ki-Ras.

Animals↗
PubMed2000

Spontaneous remission in acute type adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is a neoplastic disorder of T lymphocytes associated with human T lymphotropic virus type I (HTLV-I). The prognosis of ATL is generally poor. We present here a 79-year-old woman with spontaneous remission of acute type ATL. Spontaneous remission was preceded by surgical biopsy and pneumonia and lasted for two years until she died with pancreas cancer. Monoclonal integration of HTLV-I provirus DNA became undetectable after remission.

Adult↗
PubMed2000

Prognostic significance of serum soluble interleukin-2 receptor level in non-Hodgkin's lymphoma: a single center study in Japan.

Interleukin 2 receptor is expressed not only on the surface of activated T or B lymphocytes, but also on certain lymphoid malignancies. The receptor is released from the cell membrane as soluble form (sIL-2R). Serum sIL-2R level is a sensitive and quantitative marker of circulating peripheral blood mononuclear cell activation or specific tumor cell growth including non-Hodgkin's lymphoma (NHL). However, the relevance of serum sIL-2R levels relating to clinical outcome in adult patients with NHL remains uncertain. Therefore, we investigated the serial serum sIL-2R levels in 28 untreated patients with NHL to evaluate its correlation with clinical characteristics. High serum sIL-2R level (>1000 U/ml) at diagnosis was associated with a high incidence of treatment failure (p=0.03) and poor overall survival (p=0.057). The serum sIL-2R levels decreased significantly after achieving complete remission (p=0.003). Further larger studies are required to evaluate whether serum sIL-2R level is an independent prognostic factor or not. However, adding this parameter to those already employed in the International Prognostic Index would perhaps provide a better prognostic index for adult patients with NHL.

Adult↗
PubMed2000

Treatment of deep vein thrombosis using temporary vena caval filters after allogeneic bone marrow transplantation.

Bone marrow transplant (BMT) recipients have risk factors for deep vein thrombosis (DVT) including venous stasis caused by immobilization in the sterile unit, vessel wall damage caused by preparative regimen or indwelling catheters, and hypercoagulability caused by decreased natural anticoagulants. We successfully treated a patient who developed massive DVT in the superior vena cava after BMT with anticoagulation and the use of temporary vena caval filters. Considering the delayed complications, permanent filter is not appropriate for BMT recipients, because the risk factors for DVT associated with BMT are transient. We considered that temporary vena caval filter is a safe and useful device to prevent pulmonary embolism after DVT in BMT recipients.

Anticoagulants↗
PubMed2000

Pyogenic granuloma of the tongue early after allogeneic bone marrow transplantation for multiple myeloma.

Oral complications occur frequently after bone marrow transplantation (BMT). Some of them are caused by regimen-related toxicity of the preparative regimen, and others by infections. In addition, oral tissues are targets of graft-versus-host disease (GVHD). Oral granulomatous lesions are not a common complication after BMT, and are especially rare on the tongue. Such rare lesions reported in the literature, developed late after BMT with oral chronic GVHD. We present here a patient who developed pyogenic granuloma of the tongue early after allogeneic BMT done for multiple myeloma. Regimen-related mucositis, oral acute GVHD, the administration of cyclosporine A, and the preexisting macroglossia might be responsible for the formation of granuloma.

Bone Marrow Transplantation↗
PubMed2000

[Clinical evaluation of rhG-CSF in patients with neutropenia induced by chemotherapy for multiple myeloma].

A randomized controlled study of patients with multiple myeloma was performed to evaluate the efficacy and safety of recombinant human granulocyte colony-stimulating factor (rhG-CSF:KW-2228) in treating neutropenia induced by chemotherapy, and its influence on the dose intensity of, and response rate to, chemotherapy. As a rule, 3 courses of chemotherapy at intervals of 4 weeks were administered both to the untreated and KW-2228-treated groups. Among 98 eligible patients evaluated for neutrophil recovery, a markedly reduced duration of neutropenia was observed during each course in the KW-2228 treated group. No significant difference distinguished the two groups in terms of incidence or duration of infection. However, febrile neutropenia appeared only in the untreated group. There was no significant difference in terms of response rate or dose intensity. However, only patients in the untreated group withdrew from the study due to protracted neutropenia. These results demonstrated that KW-2228 is effective and safe, and has a significant effect on the acceleration of neutrophil recovery in patients with neutropenia induced by chemotherapy for multiple myeloma, and is useful for the completion of chemotherapy regimens.

Adolescent↗
PubMed2000

[Efficacy and safety of cefozopran (CZOP) monotherapy and combination therapy with CZOP and amikacin (AMK) for infections accompanying hematological diseases].

We evaluated efficacy and safety of monotherapy with CZOP (1-2 g x 2/day) and combination therapy with CZOP (1-2 g x 2/day) and AMK (200 mg x 2/day) for infections in patients with hematological diseases. Efficacy was evaluated in 71 patients of monotherapy group and 70 patients of combination therapy group. Underlying diseases were mostly leukemia and lymphoma. Infections included sepsis, suspected sepsis, pneumonia and so on. Efficacy in CZOP monotherapy was excellent in 21 patients (31.3%), good in 23 patients (34.3%), fair in 5 patients (7.5%) and the efficacy rate was 65.7%. On the other hand, in combination therapy, each was 14 patients (21.2%), 23 patients (34.8%), 12 patients (18.2%) and the efficacy rate was 56.1%. Side effects such as eruption were noted in 2 patients. Abnormal laboratory findings were noted in 9 patients. All side effects as well as abnormal laboratory findings were minimal. It was concluded that CZOP monotherapy was effective in the treatment of various infections accompanying hematological diseases.

Adolescent↗
PubMed2000

Catastrophic exacerbation of antiphospholipid syndrome after lung adenocarcinoma biopsy.

We describe a 60-year-old man with nephrotic syndrome due to a glomerular thrombotic microangiopathy caused by the antiphospholipid syndrome (APS) associated with a lung adenocarcinoma. Although no significant aggravation of APS was noted following renal biopsy, catastrophic exacerbation of APS occurred 3 days after a lung adenocarcinoma biopsy while warfarin and prednisolone were being administered. The patient died of multiple organ failure 37 days after the lung adenocarcinoma biopsy. This case emphasizes the need for great caution for catastrophic exacerbation of malignancy associated APS following biopsy of the underlying malignancy.

Adenocarcinoma↗
PubMed1999

Progressive impairment of kidneys and reproductive organs in mice lacking Rho GDIalpha.

The Rho small G protein family members regulate various actin cytoskeleton-dependent cell functions. The Rho GDI (GDP dissociation inhibitor) family, consisting of Rho GDIalpha, -beta, and -gamma, is a regulator that keeps the Rho family members in the cytosol as the GDP-bound inactive form and translocates the GDP-bound form from the membranes to the cytosol after the GTP-bound form accomplishes their functions. Rho GDIalpha is ubiquitously expressed in mouse tissues and shows GDI activity on all the Rho family members in vitro. We have generated mice lacking Rho GDIalpha by homologous recombination to clarify its in vivo function. Rho GDIalpha -/- mice showed several abnormal phenotypes. Firstly, Rho GDIalpha -/- mice were initially viable but developed massive proteinuria mimicking nephrotic syndrome, leading to death due to renal failure within a year. Histologically, degeneration of tubular epithelial cells and dilatation of distal and collecting tubules were readily detected in the kidneys. Secondly, Rho GDIalpha -/- male mice were infertile and showed impaired spermatogenesis with vacuolar degeneration of seminiferous tubules in their testes. Thirdly, Rho GDIalpha -/- embryos derived from Rho GDIalpha -/- female mice were defective in the postimplantation development. In addition, these morphological and functional abnormalities showed age-dependent progression. These results suggest that the signaling pathways of the Rho family members regulated by Rho GDIalpha play important roles in maintaining the structure and physiological function of at least kidneys and reproductive systems in adult mice.

Age Factors↗
PubMed1999

Afadin: A key molecule essential for structural organization of cell-cell junctions of polarized epithelia during embryogenesis.

Afadin is an actin filament-binding protein that binds to nectin, an immunoglobulin-like cell adhesion molecule, and is colocalized with nectin at cadherin-based cell-cell adherens junctions (AJs). To explore the function of afadin in cell-cell adhesion during embryogenesis, we generated afadin(-/-) mice and embryonic stem cells. In wild-type mice at embryonic days 6.5-8.5, afadin was highly expressed in the embryonic ectoderm and the mesoderm, but hardly detected in the extraembryonic regions such as the visceral endoderm. Afadin(-/-) mice showed developmental defects at stages during and after gastrulation, including disorganization of the ectoderm, impaired migration of the mesoderm, and loss of somites and other structures derived from both the ectoderm and the mesoderm. Cystic embryoid bodies derived from afadin(-/-) embryonic stem cells showed normal organization of the endoderm but disorganization of the ectoderm. Cell-cell AJs and tight junctions were improperly organized in the ectoderm of afadin(-/-) mice and embryoid bodies. These results indicate that afadin is highly expressed in the ectoderm- derived cells during embryogenesis and plays a key role in proper organization of AJs and tight junctions of the highly expressing cells, which is essential for proper tissue morphogenesis.

Actins↗
PubMed1999

Purification and cloning of a brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factors.

Activation of ADP-ribosylation factors (ARFs), approximately 20-kDa guanine nucleotide-binding proteins that play an important role in intracellular vesicular trafficking, depends on guanine nucleotide-exchange proteins (GEPs), which accelerate replacement of bound GDP with GTP. Two major families of ARF GEPs are known: approximately 200-kDa molecules that are inhibited by brefeldin A (BFA), a fungal metabolite that blocks protein secretion and causes apparent disintegration of Golgi structure, and approximately 50-kDa GEPs that are insensitive to BFA. We describe here two human brain cDNAs that encode BFA-inhibited GEPs. One is a approximately 209-kDa protein 99.5% identical in deduced amino acid sequence (1, 849 residues) to a BFA-inhibited ARF GEP (p200) from bovine brain. The other smaller protein, which is approximately 74% identical (1, 785 amino acids), represents a previously unknown gene. We propose that the former, p200, be named BIG1 for (brefeldin A-inhibited GEP1) and the second, which encodes a approximately 202-kDa protein, BIG2. A protein containing sequences found in BIG2 had been purified earlier from bovine brain. Human tissues contained a 7.5-kilobase BIG1 mRNA and a 9.4-kilobase BIG2 transcript. The BIG1 and BIG2 genes were localized, respectively, to chromosomes 8 and 20. BIG2, synthesized as a His6 fusion protein in Sf9 cells, accelerated guanosine 5'-3-O-(thio)triphosphate binding by recombinant ARF1, ARF5, and ARF6. It activated native ARF (mixture of ARF1 and ARF3) more effectively than it did any of the nonmyristoylated recombinant ARFs. BIG2 activity was inhibited by BFA in a concentration-dependent manner but not by B17, a structural analog without effects on Golgi function. Although several clones for approximately 50-kDa BFA-insensitive ARF GEPs are known, these new clones for the approximately 200-kDa BIG1 and BIG2 should facilitate characterization of this rather different family of proteins as well as the elucidation of mechanisms of regulation of BFA-sensitive ARF function in Golgi transport.

ADP-Ribosylation Factor 1↗
PubMed1999

The benefit of cochlear implantation in the Japanese elderly.

The purpose of this study was to evaluate the benefit of cochlear implant for Japanese elderly people with profound hearing loss. A questionnaire was administered to the five Japanese elderly people over 65 years old with the Nucleus 22 channel device and their family. The questionnaire was designed to gain insight into the patient's daily use and to evaluate the quality of life. Elderly patients who were implanted with the Nucleus device showed good ability to identify environmental sound and revealed no significant deterioration compared to younger patients. Implanted patients showed some difficulties in understanding speech in the noisy environment and conversation among several persons. Nevertheless, 80% of patients over 65 and their family reported communication benefits in the family and in social activities. In addition, 80% of the patients reported that they felt the better or improved quality of life after the implantation. All patients considered the implant was good for their life and would recommend a cochlear implant to a deaf friend. It is notable that 60% of patients and their family report that the recipients have become more cheerful. This study showed the cochlear implant contributes to the better quality of life in the Japanese elderly.

Aged↗