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Biomedical subjects

M Sawada

Publications and source records attributed to M Sawada.

At least 55 records · Page 3Linked to original sources
PubMed2001

Enhanced expression of transforming growth factor (TGF) -alpha precursor and TGF-beta1 during Paneth cell regeneration.

An intravenous injection of diphenylthiocarbazone (dithizone), a zinc chelator, induces selective killing and rapid regeneration of Paneth cells, which have a large amount of zinc in their cytoplasmic granules. We examined the expression pattern of transforming growth factor (TGF) -alpha and TGF-beta1 in this regenerative process. Messenger RNA expression of TGF-alpha and TGF-beta1 reached their peaks at 12 and 24 hr after dithizone injection, respectively. Protein expression of TGF-alpha precursor and TGF-beta1 increased to a maximum at 24 and 72 hr, respectively. Their immunoreactivities were localized in the epithelial cells in the vicinity of Paneth cells, whereas they were prominent in the upper half of the crypts in control rats. In conclusion, destruction of Paneth cells induced TGF-alpha precursor expression, followed by an increase of TGF-beta1 especially in the crypt bases. This unique expression pattern of two growth factors may be involved in rapid regeneration of Paneth cells.

Animals↗
PubMed2001

alpha-Synuclein forms a complex with transcription factor Elk-1.

alpha-Synuclein has been identified as a component of Lewy bodies in Parkinson's disease and diffuse Lewy body disease, and glial cytoplasmic inclusions (GCIs) in multiple system atrophy (MSA). To explore the role of alpha-synuclein in the pathogenesis, we searched for molecules interacting with alpha-synuclein and discovered that GCIs are stained by anti-Elk-1 antibody. To seek the role of Elk-1 in synucleinopathies, we cotransfected alpha-synuclein and Elk-1 to cultured cells, and found small granular structure complexes where the two molecules colocalized. Moreover, alpha-synuclein and Elk-1 were co-immunoprecipitated from the cell lysates. For formation of the complex, the presence of both ETS and B-box domains of Elk-1 was required. Although there was no evidence of direct binding between alpha-synuclein and Elk-1, we discovered that alpha-synuclein and Elk-1 both bind to ERK-2, a MAP kinase. The effect of alpha-synuclein on the MAP kinase pathway was assessed using the Pathdetect system, which showed prominent attenuation of Elk-1 phosphorylation with alpha-synuclein, and especially A53T mutant. Our results suggest that alpha-synuclein reacts with the MAP kinase pathway, which might cause dysfunction of neurons and oligodendrocytes and lead to neurodegeneration in Parkinson's disease and MSA.

Amino Acid Motifs↗
PubMed2001

A dose escalation study of paclitaxel and carboplatin in untreated Japanese patients with advanced non-small cell lung cancer.

BACKGROUND: The combination of paclitaxel (225 mg/m(2), 3-h infusion) and carboplatin (area under the curve 6) is widely used for non-small cell lung cancer in the USA. In Japan, however, the recommended dose for single-use paclitaxel in 3-h infusion is 210 mg/m(2) and the optimal dose of this agent in combination with carboplatin has not been established. This dose escalation study was designed to determine the maximum tolerated dose of paclitaxel in 3-h infusion plus carboplatin at a fixed dose of area under the curve 6 for Japanese patients with advanced, untreated non-small cell lung cancer. METHODS: Between October 1999 and May 2000, 19 patients were enrolled and 18 of these patients were evaluable for toxicity. Chemotherapy consisted of carboplatin area under the curve 6 and an escalated dose of paclitaxel on day 1 every 3-4 weeks. The initial dose of paclitaxel was 175 mg/m(2) and was increased by 25 mg/m(2) at each dose level. RESULTS: Neutropenia was the major toxicity observed, but was not dose related. Febrile neutropenia was not observed. No grade 3 or more peripheral neuropathy, myalgia or arthralgia was reported. The maximum tolerated dose was not determined even at the highest paclitaxel dose level (225 mg/m(2)) in this study. Partial responses were observed in six of the 19 patients (31.6%). CONCLUSION: We conclude that paclitaxel at 225 mg/m(2) in 3-h infusion and carboplatin area under the curve 6 can safely be given to Japanese patients with non-small cell lung cancer.

Adult↗
PubMed2001

A phase I/II study of cisplatin and vinorelbine chemotherapy in patients with advanced non-small cell lung cancer.

BACKGROUND: A combination of cisplatin and vinorelbine chemotherapy is effective in cases of advanced non-small cell lung cancer, but the optimum administration schedule for both drugs has not yet been defined. The aim of this study was to determine the maximum dose of vinorelbine that can be tolerated while receiving a fixed dose of cisplatin every 3 weeks and to observe the response in Japanese patients with advanced non-small cell lung cancer who had not previously received chemotherapy. METHODS: Cisplatin was given at a dose of 80 mg/m2 on day 1. Vinorelbine was administered on days 1 and 8 at a starting dose of 25 mg/m2 that was then increased by 5 mg/m2 increments. This treatment was repeated every 3 weeks. RESULTS: Twenty-one patients received a total of 54 chemotherapy cycles consisting of three different vinorelbine dosages. Toxicity and efficacy were evaluated in all of the patients. The main dose-limiting toxicity was neutropenia. Grades 3-4 leukopenia and neutropenia were observed in 57% and 86% of all cycles, respectively. These conditions were reversible and did not result in death from toxicity. The most severe non-hematological toxicity symptom was a grade 3 infection and reaction at the site of injection. The maximum tolerated dose of vinorelbine was 35 mg/m2. The objective response was noted in one of six patients at dose level 1, in four of 12 patients at dose level 2 and in two of three patients at dose level 3. CONCLUSION: The recommended doses were 80 mg/m2 for cisplatin and 30 mg/m2 for vinorelbine. The combination of cisplatin and vinorelbine repeated every 3 weeks is well tolerated and has shown promising anti-tumor activity against non-small cell lung cancer.

Adult↗
PubMed2001

Crystallization and preliminary X-ray analysis of a novel pectolytic enzyme, polymethoxygalacturonase SX1 from Trichosporon penicillatum.

A novel pectolytic enzyme, polymethoxygalacturonase SX1 from Trichosporon penicillatum, with a molecular weight of 36 kDa was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 1000 as a precipitant. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 165.6, b = 61.0, c = 48.7 A, beta = 93.1 degrees. The calculated V(M) based on one molecule per asymmetric unit was 3.40 A(3) Da(-1). A native data set was collected to 2.08 A resolution from a crystal on a Cu Kalpha rotating-anode X-ray source. A molecular-replacement solution was obtained using the program AMoRe and the structure of endopolygalacturonase II from Aspergillus niger as a model.

Crystallization↗
PubMed2001

Crucial role of calpain in hypoxic PC12 cell death: calpain, but not caspases, mediates degradation of cytoskeletal proteins and protein kinase C-alpha and -delta.

Ca2+ influx is one of the main causative events in hypoxic PC12 cell death, because an extracellular Ca2+ chelator, ethylene glycol bis (2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) inhibited and Ca2+ ionophore A23187 mimicked the hypoxic cell death. The hypoxic cell death was markedly prevented by a broad spectrum caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD-FMK) as well as a calpain inhibitor, calpeptin, as assessed by nuclear staining with Hoechst 33258 and lactate dehydrogenase release. The processing of procaspase-3 was inhibited by z-VAD-FMK, but not by calpeptin. In contrast, z-VAD-FMK failed to block the proteolytic cleavage of fodrin-alpha, a preferential substrate for calpain. On the other hand, degradation of actin and fodrin-alpha was prevented by calpeptin but not by z-VAD-FMK. In addition, not only protein kinase C (PKC)-alpha but also PKC-delta were cleaved to generate approximately 46 kDa fragments. The PKC fragmentation was inhibited by calpeptin but not by z-VAD-FMK. These findings suggest that the extracellular Ca2+ influx induced by hypoxic stress activates calpain, resulting in the degradation of cytoskeletal proteins and generation of PKC fragments almost independently of caspase activation. Therefore, calpain may play an important role in hypoxic PC12 cell death.

Animals↗
PubMed2001

[Childhood t(8;21) acute myelocytic leukemia: a comparison of clinical features and risk factors with adult cases].

Despite the abundance of reports describing adult cases of t(8;21) acute myelocytic leukemia (AML), childhood cases have received little attention. We retrospectively investigated 14 childhood cases of t(8;21) AML, and compared their clinical characteristics with those of adult cases, focusing on the risk factors for poor prognosis. Seventy-one percent of the patients had fever. Their mean leukocyte count was 12,700/microliter, and they showed decreased NAP activity. The cell surface showed positivity for CD13, 33, 19, 34, and HLA-DR. The complete remission rate was 100%, and relapse was observed in three of the patients. Bone marrow eosinophilia was present in a smaller proportion of the childhood cases than in the adult cases. Although an increased leukocyte count, tumor formation, and other risk factors have been reported in adults, there was no correlation between these factors and prognosis in our childhood cases. As children who showed AML relapse had TdT-positive blasts, detectable blast TdT activity may be a risk factor for relapse in childhood cases of t(8;21) AML. However, to confirm this, a study with a larger subject base should be conducted.

Adolescent↗
PubMed2001

[Multiple myeloma complicated by bilateral abducens nerve palsy due to a tumor in the clivus].

A 62-year-old woman was admitted to our hospital because of double vision. Bone marrow aspiration revealed normal cellularity with 21.6% atypical plasma cells. Immunoelectrophoresis revealed a monoclonal component of IgG kappa in the patient's serum. Coronal and sagittal cranial MRI images showed a tumor in the clivus behind the sella turcica. The patient was diagnosed as having multiple myeloma complicated by double vision due to compression of the bilateral abducens nerve by a plasmacytoma. VAD therapy consisting of vincristine, doxorubicin and dexamethasone, followed by irradiation of the clivus tumor achieved only a transient therapeutic effect, and the double vision and bone disease worsened. Cranial nerve palsy may be a significant complication of multiple myeloma.

Abducens Nerve Diseases↗
PubMed2001

[Diffuse large B-cell lymphoma expressing cytoplasmic IgM and kappa in a patient with lambda-type primary macroglobulinemia].

A 69-year-old woman who had had lambda-type primary macroglobulinemia (PMG) since December 1993 was admitted in October 1997 because of obstructive jaundice due to compression of the common bile duct by a retroperitoneal tumor. A biopsy sample was obtained by exploratory laparotomy, and from this a diagnosis of diffuse large cell lymphoma (DLCL) expressing cytoplasmic IgM/kappa was made. Partial remission was obtained after 6 courses of combination chemotherapy consisting of pirarubicin, cyclophosphamide, vincristine and prednisolone. However, the DLCL was generally progressive, and the patient died in August 1998 due to multiple organ failure. There was no difference in the plasma monoclonal IgM/lambda level before and during the course of DLCL. The clone of the DLCL may have been different from that of the PMG.

Aged↗
PubMed2001

[A case of Churg-Strauss syndrome in which positive rheumatoid factor and MPO-ANCA preceded the development of clinical symptoms of vasculitis].

A 52-year-old man in whom bronchial asthma had been diagnosed in 1995 was admitted for the treatment of Churg-Strauss syndrome in June 1997. Positive tests MPO-ANCA and rheumatoid factor preceded the symptoms of vasculitis for several months. A skin biopsy revealed infiltration of eosinophils in the vessel walls, and the diagnosis of Churg-Strauss syndrome was confirmed. After systemic administration of corticosteroids, the symptoms other than mononeuritis improved markedly, and his MPO-ANCA and rheumatoid factor became negative. Rheumatoid factor and MPO-ANCA may be useful for the early diagnosis of Churg-Strauss syndrome in patients with bronchial asthma in which a well-controlled disease develops into an intractable condition.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2000

Increased phospholipase D2 activity during hypoxia-induced death of PC12 cells: its possible anti-apoptotic role.

During hypoxic incubation (1% O2) of PC12 cells, the PLD activity was transiently increased within 12h, followed by a gradual decrease. In the in vitro assay, the increased PLD activity was independent of GTPgammaS required for PLD1 or of oleic acid for PLD(OA), suggesting the activation of PLD2. The level of PLD2 protein showed no change up to 12h but a gradual decrease after 24 h. Pretreatment of cells with S. chromofuscus PLD resulted in inhibition of hypoxia-induced apoptotic cell death. In contrast, 1-butanol, but not 2-butanol, potentiated cell death. Moreover, the number of apoptotic cells significantly reduced in PC12 cells over-expressing PLD2. These results raise the possibility that PLD2 activation may play an anti-apoptotic role in hypoxia-induced cell death.

1-Butanol↗
PubMed2000

Differentiated regulation of allo-antigen presentation by different types of murine microglial cell lines.

We established granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent murine microglial clones and investigated the immune properties of four individual clones. All four clones expressed MHC class I and CD54 (ICAM-1) at similar levels. The 5-2, Ra2, and 6-3 clones expressed CD80 (B7-1), CD86 (B7-2), and MHC class II at low, medium, and high levels, respectively. Only the 6-3 clone expressed CD40. Generally, the levels of co-stimulation and CD 40 signals had a profound effect on the response to antigens. The 5-2, Ra2, and 6-3 clones, however, stimulated allogenic T-cell proliferation to the same extent or less compared to spleen cells. Although the 6-1 clone expressed co-stimulatory and MHC molecules at levels similar to Ra2, it suppressed allogenic T-cell proliferation, unlike Ra2. Thus, allo-antigen presentation by microglial clones was not correlated with the expression of CD40 and co-stimulatory molecules. When microglial clones were fixed with paraformaldehyde, they enhanced IL-2-dependent T-cell proliferation according to the level of their expression of co-stimulatory molecules. Furthermore, conditioned medium from the 6-1 clone inhibited the T-cell response to allo-antigen. This indicates that some factor(s) derived from a microglial subtype may play an important role in the regulation of T-cell proliferation in addition to the molecules involved in antigen presentation. Moreover, these results also suggest that there may be specialized subtypes of microglia that regulate the immune response in the CNS.

Animals↗
PubMed2000

Cancer chemotherapy and somatic cell mutation.

The occurrence of a second neoplasm is one of the major obstacles in cancer chemotherapy. The elucidation of the genotoxic effects induced by anti-cancer drugs is considered to be helpful in identifying the degree of cancer risk. Numerous investigations on cancer patients after chemotherapy have demonstrated: (i) an increase in the in vivo somatic cell mutant frequency (Mf) at three genetic loci, including hypoxanthine-guanine phosphoribosyl-transferase (hprt), glycophorin A (GPA), and the T-cell receptor (TCR), and (ii) alterations in the mutational spectra of hprt mutants. However, the time required for and the degree of such changes are quite variable among patients even if they have received the same chemotherapy, suggesting the existence of underlying genetic factor(s). Accordingly, some cancer patients prior to chemotherapy as well as patients with cancer-prone syndrome have been found to show an elevated Mf. Based on the information obtained from somatic cell mutation assays, an individualized chemotherapy should be considered in order to minimize the risk of a second neoplasm.

Antineoplastic Agents↗
PubMed2000

Influence of Bax or Bcl-2 overexpression on the ceramide-dependent apoptotic pathway in glioma cells.

Ceramide has recently been regarded as a potential mediator of apoptosis. In the present study, the effects of Bcl-2 and Bax on the ceramide-mediated apoptotic pathways were examined in glioma cells overexpressing Bcl-2 or Bax. Etoposide, cisplatin and tumor necrosis factor-alpha induced apoptosis of C6 rat glioma cells which was associated with ceramide formation due to activation of neutral sphingomyelinase, followed by release of mitochondrial cytochrome c into the cytosol and activation of caspases-9 and -3. The growth of C6 cells stably overexpressing either Bcl-2 or Bax was almost equal to that of the vector-transfected cells. Bax overexpression enhanced etoposide-induced apoptosis through acceleration of cytochrome c release and caspases activation. However, Bax had no effect on ceramide formation. Similar findings were obtained in C6 cells and U87-MG human glioblastoma cells which were transiently overexpressed with Bax. In contrast, Bcl-2 overexpression resulted in a retardation of the apoptotic process via prevention of cytochrome c release and caspases activation, and ceramide formation was also blocked when Bcl-2 was highly overexpressed in glioma cells. In addition, transient overexpression of Bcl-xL also exerted inhibitory effects on ceramide formation and apoptotic cell death induced by etoposide. These results indicate that Bax promotes apoptosis regardless of ceramide formation and that Bcl-2 or Bcl-xL prevents ceramide formation by repressing neutral sphingomyelinase as well as ceramide-induced cytochrome c release. Oncogene (2000) 19, 3508 - 3520

Animals↗
PubMed2000

Isolation of Neospora caninum from the brain of a naturally infected adult dairy cow.

Neospora caninum was isolated from the brain of a 2-year-old dairy cow that had aborted confirmed N. caninum-infected fetuses on two occasions. The cow had an indirect fluorescent antibody titer of 1:1600 to N. caninum. The cow was killed 24 days after its second abortion and the brain was bioassayed for N. caninum in nude mice. Multifocal areas of perivascular cuffing and glial nodules were observed in the cerebrum and mesencephalon of the cow, but N. caninum was not identified in histological sections of the brain. All three nude mice inoculated with brain homogenate of the cow, developed emaciation and paralysis. Microscopical examination of the nude mice revealed systemic N. caninum infection with demonstrable tachyzoites in various organs. The parasites isolated from fresh mouse brain were transferred successfully into Vero cell cultures. PCR procedure on the purified tachyzoites obtained from the Vero cell cultures amplified the specific DNA sequence for N. caninum.

Animals↗