Biomedical subjects

Masao Murakami

Publications and source records attributed to Masao Murakami.

At least 19 recordsLinked to original sources

PubMed2006

Hrt and Hes negatively regulate Notch signaling through interactions with RBP-Jkappa.

Notch signaling is central to cell differentiation, organ development, and apoptosis. Upon ligand binding, the Notch intracellular domain (NotchIC) translocates to the nucleus to interact with its DNA-binding partner, RBP-Jkappa. The NotchIC-RBP-Jkappa complex activates target genes, such as those encoding the Hrt and Hes families of basic-helix-loop-helix (bHLH) transcriptional repressors. Hrt transcripts are enriched in the developing cardiovascular system, and mice lacking Hrt2 have cardiac malformations. Here we show that Hrt2 and Hes1 interact with RBP-Jkappa to negatively regulate Notch-dependent activation of Hrt and Hes expression. The bHLH domain of Hrt2 was necessary for this interaction, and disrupting the protein complex abrogated the negative autoregulation. The interaction did not interfere with the formation or DNA-binding of the NotchIC-RBP-Jkappa complex, indicating direct inhibition by Hrt and Hes as co-repressors. These findings suggest a novel mechanism for negative feedback on Notch signaling that requires RBP-Jkappa to interact physically with Hrt and Hes.

Animals↗

PubMed2006

Treatment results of chemoradiotherapy for clinical stage I (T1N0M0) esophageal carcinoma.

PURPOSE: In 1991, we started a clinical prospective trial for operable esophageal carcinoma, foreseeing organ preservation, to assess the treatment results after definitive chemoradiotherapy (CRT) for clinical Stage I (T1N0M0) esophageal cancer. PATIENTS AND METHODS: Between 1992 and 2003, 63 patients were enrolled in this study. Tumor depth was mucosal cancer (T1a) in 23 and submucosal cancer (T1b) in 40. CRT consisted of 55-66 Gy/50-60 fractions (median, 59.4 Gy); from 1 to 3 cycles (median, 2) of concurrent chemotherapy (Cisplatin and 5-fluorouracil), followed by high-dose-rate intraluminal brachytherapy 10-12 Gy/2-3 fractions. RESULTS: The 5-year overall and cause-specific and disease-free survival rates were 66.4%, 76.3%, and 63.7%, respectively. The 5-year cause-specific survival rates for T1a and T1b cancer patients were 85.2% and 70.0%, respectively (p = 0.06). The 5-year disease-free survival rates for T1a and T1b were 84.4% and 50.5%, respectively (p < 0.01). Esophageal fistula as a late toxicity occurred in 2 patients (G4: 1; G5: 1), and esophageal stricture requiring a liquid diet occurred in 2 patients. Pericardial effusion was observed in 3 patients. CONCLUSION: We confirmed that patients with T1N0M0 esophageal carcinoma had their esophagus preserved in 89.2% of cases after definitive CRT, and the survival rates were equivalent to those of previous reports of surgery.

Aged↗

PubMed2006

Treatment results of radiotherapy for carcinoma of the cervical esophagus.

The methods and results of treatment for cancer of the cervical esophagus differ from those for cancer of the thoracic esophagus. Our objective was to retrospectively review the outcome for cervical esophageal cancer patients treated with radiotherapy. Twenty-seven patients with carcinoma of the cervical esophagus treated with definitive radiotherapy from 1988 to 2002 were enrolled in the study. Clinical stage (UICC 1997) was stage I in five, II in six, III in 12 and IV in four. Concurrent head and neck malignancy was found in six patients (22%). The mean radiation dose was 66 Gy. Concurrent chemotherapy (cisplatin and 5-fluorouracil) was performed in 23 patients. The actuarial overall survival rates at 1, 3 and 5 years were 55.6%, 37.9% and 37.9%, respectively, with a median survival of 13.9 months. In the patients with stage I, the 3-year and 5-year survival rates were 75% and 75%, respectively. With univariate analysis, only two of the possible prognostic factors were found to actually influence survival: performance status (p < 0.01) and tumor length (p < 0.01). The survival of patients with cervical esophageal cancer remains poor. It is thought that organ preservation is possible by definitive chemoradiation for early cancer.

Aged↗

PubMed2005

A WW domain protein TAZ is a critical coactivator for TBX5, a transcription factor implicated in Holt-Oram syndrome.

The T-box transcription factor TBX5 plays essential roles in cardiac and limb development. Various mutations in the TBX5 gene have been identified in patients with Holt-Oram syndrome, which is characterized by congenital defects in the heart and upper extremities. In this study, we identified a WW-domain-containing transcriptional regulator TAZ as a potent TBX5 coactivator. TAZ directly associates with TBX5 and markedly stimulates TBX5-dependent promoters by interacting with the histone acetyltransferases p300 and PCAF. YAP, a TAZ-related protein with conserved functional domains, also stimulates TBX5-dependent transcription, possibly by forming a heterodimer with TAZ. TBX5 lacks a PY motif, which mediates the association of other proteins with TAZ, and interacts with TAZ through multiple domains including its carboxyl-terminal structure. Truncation mutants of TBX5 identified in patients with Holt-Oram syndrome were markedly impaired in their ability to associate with and be stimulated by TAZ. These findings reveal key roles for TAZ and YAP in the control of TBX5-dependent transcription and suggest the involvement of these coactivators in cardiac and limb development.

Abnormalities, Multiple↗

PubMed2005

Transcriptional activity of Pax3 is co-activated by TAZ.

Pax3 is a transcription factor which functions in embryonic development and human diseases. In a yeast two-hybrid screen with full-length Pax3 as bait, we isolated a clone encoding transcriptional co-activator with PDZ-binding motif (TAZ) from an E10.5 mouse embryo cDNA library. Co-immunoprecipitation and nuclear co-localization of TAZ with Pax3 suggest that their association is functionally relevant. In situ hybridization revealed TAZ and Pax3 expression to partially overlap in the paraxial mesoderm, limb buds, and the neural tube. In C2C12 myoblast cells and NIH3T3 cells, TAZ enhanced the transcriptional activity of Pax3 on artificial and microphthalmia-associated transcription factor promoter-luciferase constructs, suggesting that TAZ can function as a co-activator of Pax3. Functional interaction between Pax3 and TAZ may provide a clue to clarifying the mechanism by which Pax3 serves as a transcriptional activator during embryogenesis.

Acyltransferases↗

PubMed2005

Development of interspecies cloned embryos in yak and dog.

Interspecies nuclear transfer (NT) could be an alternative to replicate animals when supply of recipient oocytes is limited or in vitro embryo production systems are incomplete. In the present study, embryonic development was assessed following interspecies NT of donor cumulus cells derived from yak and dog into the recipient ooplasm of domestic cow. The percentages of fusion and subsequent embryo development to the eight-cell stage of interspecies NT embryos were comparable to those of intraspecies NT embryos (cow-cow NT embryos). The percentage of development to blastocysts was significantly lower (p < 0.05) in yak-cow NT embryos than that in cow-cow NT embryos (10.9% vs. 39.8%). In dog-cow NT embryos, only one embryo (0.4%) developed to the blastocyst stage. These results indicate that interspecies NT embryos possess equally developmental competence to the eight-cell stage as intraspecies NT embryos, but the development to blastocysts is very low when dog somatic cells are used as the donor nuclei.

Animals↗

PubMed2005

[Survey of patients' impressions of radiotherapy and their need for additional medical information: Japanese domestic survey of 1,529 patients in 2002].

PURPOSE: We clarified the images, impressions, and information about radiotherapy in standard Japanese patients and, at the same time, investigated their need for information about radiotherapy, in order to identify what we, as radiation oncologists, should do to decrease patient anxiety and create good physician-patient relationships. MATERIALS AND METHODS: We handed out 10 questionnaires to 1529 patients from April 2002 through July 2002 in 22 Japanese institutions that were equipped with radiotherapy machines. Questionnaires contained 10 items asking about patients' background, their impression of radiotherapy, frequency of exposure to information about radiotherapy, need to obtain information about radiotherapy, and ideal additional medical informational resources or their content. RESULTS: About 60% of patients had had the opportunity to obtain information about radiotherapy "sometimes" or "often," but 80% of them were not satisfied with the availability of information and answered that it was inadequate. Ten percent responded that they had no idea about radiotherapy. Thirty percent felt unspecified anxiety concerning radiotherapy, and those who had less chance to be exposed to information about radiotherapy felt more anxiety than the others (33.2% vs. 25.2%, p=0.0008). The need for "explanation and information about adverse effects" was the top priority, followed by "explanation of outcome." Although they generally obtained information from their physician (radiation oncologist), they also wanted additional information via written media (662 patients, 43%). However, patients who were over 60 years old most wanted to obtain additional medical information directly from their own radiation oncologist (37.7%). CONCLUSION: Information about radiotherapy given to patients and the general public is still insufficient in Japan. To fully utilize radiotherapy, which is a very effective treatment option against cancer, and to reduce anxiety about radiotherapy among cancer patients, more information is necessary.

Adult↗

PubMed2005

A case of hepatocellular carcinoma initially treated by carbon ions, followed by protons for marginal recurrence with portal thrombus.

We report a case of hepatocellular carcinoma (HCC), initially treated by carbon ions, then subsequently by protons for marginal recurrence. A 52-year-old man with stage II HCC was enrolled in the clinical study for carbon ion therapy. A total dose of 52.5 GyE in 8 fractions was delivered through a right lateral port for 13 days. Dynamic CT performed 7 months after the initiation of carbon ion therapy showed a decrease in the size of the tumor. Dynamic CT performed 12 months after the therapy revealed marginal recurrence of HCC accompanied with portal vein tumor thrombus (PVTT). Proton therapy of 66 GyE in 22 fractions was delivered through posterior and right lateral ports for 33 days. Dynamic CT performed 3 months after the initiation of proton therapy showed a regression of the recurrent tumor and disappearance of the PVTT. No serious adverse effects were observed during or after these two treatments. He was free from further recurrence 27 months after the initiation of the first carbon ion therapy. Both carbon ions and protons were effective with minimal side effects.

Carbon↗

PubMed2004

Hairy-related transcription factors inhibit GATA-dependent cardiac gene expression through a signal-responsive mechanism.

Combinatorial actions of transcription factors in multiprotein complexes dictate gene expression profiles in cardiac development and disease. The Hairy-related transcription factor (HRT) family of basic helix-loop-helix proteins is composed of transcriptional repressors highly expressed in the cardiovascular system. However, it has remained unclear whether HRT proteins modulate gene expression driven by cardiac transcriptional activators. Here, we have shown that HRT proteins inhibit cardiac gene transcription by interfering with GATA transcription factors that are implicated in cardiac development and hypertrophy. HRT proteins inhibited GATA-dependent transcriptional activation of cardiac gene promoters such as the atrial natriuretic factor (ANF) promoter. Adenovirus-mediated expression of Hrt2 suppressed mRNA expression of ANF and other cardiac-specific genes in cultured cardiomyocytes. Among various signaling molecules implicated in cardiomyocyte growth, constitutively active Akt1/protein kinase B alpha relieved Hrt2-mediated inhibition of GATA-dependent transcription. HRT proteins physically interacted with GATA proteins, and the basic domain of HRT was critical for physical association as well as transcriptional inhibition. These results suggest that HRT proteins may regulate specific sets of cardiac genes by modulating the function of GATA proteins and other cardiac transcriptional activators in a signal-dependent manner.

Animals↗

PubMed2004

Differential cooperation between dHAND and three different E-proteins.

dHAND is a transcription factor belonging to the class B basic helix-loop-helix protein family and is expressed during embryogenesis in the heart, branchial arches, limb buds, and neural crest derivatives. Despite much study, the molecular mechanisms involved in the regulation of dHAND activity are not well understood. We therefore carried out yeast two-hybrid screening using full-length dHAND as bait, which led to identification of several dHAND-binding proteins, including three E-proteins: E2A, ME2, and ALF1. Subsequent analysis revealed that although their heterodimerization and transcriptional activities were similar, dHAND/E-protein heterodimers bind to an E-box element with differing affinities, suggesting they have distinct DNA binding specificities. Moreover, in situ hybridization showed that E-protein genes are expressed fairly ubiquitously among embryonic tissues, including the branchial arches and limb buds. By contrast, little signal was detected in the heart, suggesting that dHAND complexes with partners other than E-proteins in cardiac tissue.

Animals↗

PubMed2004

Status of the clinical work at Hyogo.

On April 1, 2001, the Hyogo Ion Beam Medical Center (HIBMC) was opened as the first facility in the world to provide ion beam therapy using 2 types of beams, protons and carbon-ions. We will introduce the HIBMC, and report the results of the clinical study and general practice.

Carbon↗

PubMed2004

Relationship between DNA fragmentation and nuclear status of in vitro-matured porcine oocytes: role of cumulus cells.

The present study was conducted to investigate the effects of the attachment of cumulus cells to oocytes and coculture with cumulus cells during maturation culture on the nuclear status and DNA fragmentation of porcine denuded oocytes (DOs). In the first experiment, cumulus cells were removed from cumulus-oocyte complexes (COCs) at 0, 8, 16, 24 or 32 h after the onset of maturation culture and the DOs were then cultured in their original droplets until 42 h of culture was reached. In the second experiment, all COCs were denuded before the onset of culture and the DOs were cocultured with their removed cumulus cells. The DOs were transferred into fresh medium at 0, 8, 16, 24 or 32 h after the onset of coculture with cumulus cells and then cultured until 42 h of culture was reached. After culture, DNA fragmentation and the nuclear status of oocytes were examined using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) method. When the DOs were returned to the same droplets after removal of the cumulus cells, the removal of the cumulus cells after 16 h of culture significantly decreased the proportion of oocytes remaining at the germinal vesicle (GV) stage. However, coculture treatment of DOs in the presence of their removed cumulus cells had no significant effects on the GV breakdown (GVBD) of oocytes. There were no significant differences in the proportion maturing to MII oocytes among the groups following removal of cumulus cells after the onset of maturation culture; however, DOs cocultured with cumulus cells until the end of maturation culture exhibited an increased maturation rate compared with DOs cocultured for 8 and 16 h. The total proportion of TUNEL-positive oocytes of oocytes remaining at the GV stage was higher than that of oocytes reaching other stages, irrespective of the removal of cumulus cells and coculture treatments. However, coculture for more than 16 h decreased the total proportion of TUNEL-positive oocytes. Our results indicate that the attachment of cumulus cells to oocytes may have a critical role for oocytes undergoing GVBD and that coculture with cumulus cells promotes the ability of oocytes to complete maturation. Moreover, coculture with cumulus cells may assist the oocyte to avoid undergoing DNA fragmentation.

Animals↗

PubMed2004

Experience with conformal proton therapy for early prostate cancer.

A study was conducted to evaluate the use of proton beam therapy for the treatment of organ-confined prostate cancer. This is a preliminary assessment of treatment-related morbidity and tumor response. Sixteen patients with T1-T2b prostate cancer underwent proton beam therapy. Acute and late toxicity was scored according to the National Cancer Institute Common Toxicity Criteria Grading System (version 2.0, April 1999) and to the Radiation Therapy Oncology Group grading system, respectively. Local control was assessed using magnetic resonance imaging (MRI) and prostate-specific antigen (PSA) values. Although skin toxicity and bladder irritability were commonly observed, none of the patients developed grade III or IV toxicity. Of 9 patients in whom the primary lesion was detected by MRI, partial response and no change (NC) was observed in 6 (66.7%) and 3 (33.3%) patients, respectively. Four patients presented normal PSA value before treatment due to the previous endocrine therapy. However, the other 12 patients with elevated PSA value before treatment showed complete response. No patients showed PSA failure within the median follow-up period of 11.9 months. Although longer follow-up is necessary, minimum toxicity and good short-term clinical responses were observed following proton beam therapy in T1-T2 prostate cancer patients.

Aged↗

PubMed2004

Akt-dependent phosphorylation negatively regulates the transcriptional activity of dHAND by inhibiting the DNA binding activity.

HAND2/dHAND is a basic helix-loop-helix transcription factor expressed in the heart and neural crest derivatives during embryogenesis. Although dHAND is essential for branchial arch, cardiovascular and limb development, its target genes have not been identified. The regulatory mechanisms of dHAND function also remain relatively unknown. Here we report that Akt/PKB, a serine/threonine protein kinase involved in cell survival, growth and differentiation, phosphorylates dHAND and inhibits dHAND-mediated transcription. AU5-dHAND expressed in 293T cells became phosphorylated, possibly at its Akt phosphorylation motif, in the absence of kinase inhibitors, whereas the phosphatidylinositol 3-kinase inhibitor wortmannin and the Akt inhibitor NL-71-101, but not the p70 S6 kinase inhibitor rapamycin, significantly reduced dHAND phosphorylation. Coexpression of HA-Akt augmented dHAND phosphorylation at multiple serine and threonine residues mainly located in the bHLH domain and, as a result, decreased the transcriptional activity of dHAND. Consistently, alanine mutation mimicking the nonphosphorylation state abolished the inhibitory effect of Akt on dHAND, whereas aspartate mutation mimicking the phosphorylation state resulted in a loss of dHAND transcriptional activity. These changes in dHAND transcriptional activity were in parallel with changes in the DNA binding activity rather than in dimerization activity. These results suggest that Akt-mediated signaling may regulate dHAND transcriptional activity through the modulation of its DNA binding activity during embryogenesis.

Amino Acid Sequence↗

PubMed2003

Potential preventive effects of follistatin-related protein/TSC-36 on joint destruction and antagonistic modulation of its autoantibodies in rheumatoid arthritis.

We previously reported that follistatin-related protein (FRP)/TSC-36 was one of the target antigens of autoantibodies in rheumatoid arthritis (RA) and that the appearance of serum autoantibodies to FRP correlated to disease activity in RA. However, the significance of FRP in autoimmunity remained to be explained due to the unknown function of FRP. Here, we disclose in part the function of FRP. Transforming growth factor (TGF)-beta augmented FRP gene expression in synovial cells. FRP reduced synovial production of matrix metalloproteinase (MMP)-1, MMP-3 and prostaglandin E(2), potent agonists of joint destruction in RA. In contrast, autoantibodies to FRP from patients with RA increased their production by blocking FRP activity, probably in the autocrine system. Moreover, FRP down-regulated synovial expression of FOS (c-fos), which seemed responsible for the reduction in MMP-1 and MMP-3 caused by FRP. Therefore, FRP and its autoantibody can be regarded as defensive and offensive factors respectively in rheumatoid arthropathy. The major epitope of autoantibodies to FRP was mapped to the sequence LKFVEQNE (residues 169-176) and homologous sequences were found in proteins from Escherichia coli, Epstein-Barr virus, etc. FRP and its autoantibody may provide some clues to elucidate the process of disease development and a new approach to the design of therapeutics in RA.

Animals↗

PubMed2002

Preclinical biological assessment of proton and carbon ion beams at Hyogo Ion Beam Medical Center.

PURPOSE: To assess the biologic effects of proton and carbon ion beams before clinical use. METHODS AND MATERIALS: Cultured cells from human salivary gland cancer (HSG cells) were irradiated at 5 points along a 190 MeV per nucleon proton and a 320 MeV per nucleon carbon ion beam, with Bragg peaks modulated to 6 cm widths. A linac 4 MV X-ray was used as a reference. Relative biologic effectiveness (RBE) values at each point were calculated from survival curves. Cells were also irradiated in a cell-stack phantom to identify that localized cell deaths were observed at predefined depth. Total body irradiation of C3H/He mice was performed, and the number of regenerating crypts per jejunal section was compared to calculate intestinal RBE values. For carbon ion and referential 4 MV X-ray beams, mouse right legs were irradiated by four-fractional treatment and followed up for skin reaction scoring. RESULTS: RBE values calculated from cell survival curves at the dose that would reduce cell survival to 10% (D10) ranged from 1.01 to 1.05 for protons and from 1.23 to 2.56 for carbon ions. The cell-stack phantom irradiation revealed localized cell deaths at predefined depth. The intestinal RBE values ranged from 1.01 to 1.08 for protons and from 1.15 to 1.88 for carbon ions. The skin RBE value was 2.16 at C320/6 cm spread-out Bragg peak (SOBP) center. CONCLUSION: The radiobiologic measurements of proton and carbon ion beams at Hyogo Ion Beam Medical Center are consistent with previous reports using proton beams in clinical settings and carbon ion beams with similar linear energy transfer (LET) values.

Animals↗

PubMed2002

Rescue of AAV by antibody-induced Fas-mediated apoptosis from viral DNA integrated in HeLa chromosome.

Adenoassociated virus (AAV) provirus in latently infected cells is rescued by superinfection with adenovirus. We examined helper-independent rescue of AAV by Fas-mediated apoptosis from the HeLa lines with AAV DNA integrated in chromosome (HeLa/AAV). In HeLa/AAV, anti-Fas antibody was found to induce low-level production of AAV virions, as detected by the presence of AAV DNA protected from DNase digestion. The antibody induced higher virion production in Fas-enriched HeLa/AAV, which was generated by transfecting HeLa/AAV with an expression plasmid for Fas, than in HeLa/AAV, and the rescued virions were shown to be infectious as assayed along with adenovirus. The antibody also induced apoptotic DNA fragmentation, as detected by staining intracellular fragmented DNA and electrophoresis, in HeLa/AAV and, more markedly, in Fas-enriched HeLa/AAV. Furthermore, an inhibitor for caspase-8 suppressed both the AAV virion production and the DNA fragmentation. Thus, the integrated AAV DNA is likely to be induced to initiate a low level of replication when Fas-mediated apoptosis is activated in HeLa cells.

Animals↗

PubMed2002

Usefulness of positron-emission tomographic images after proton therapy.

PURPOSE: To examine the positron emission tomography (PET) image obtained after proton irradiation and investigate the usefulness of the image for confirmation of the irradiated volume in proton radiotherapy (RT). METHODS AND MATERIALS: A homogenous phantom was irradiated separately by carbon-ion and proton beams and the images obtained were compared. The PET images of cancer patients just after proton RT were then taken after informed consent. RESULTS: In the PET image produced by carbon-ion beams, the high pixel counts in the image corresponded to the Bragg peak; however, in that produced by proton beams, they were visible throughout the entire track of the proton beams and were not related to the Bragg peak. The PET image of patients treated with proton RT was similar to that of the phantom experiment. CONCLUSION: The PET image after proton RT was different from that of carbon-ion RT. It was found that the PET image was very useful in proton RT to verify treatment planning.

Brain↗