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Biomedical subjects

M Ohashi

Publications and source records attributed to M Ohashi.

At least 19 recordsLinked to original sources
PubMed2007

Cancer of the gastric stump following distal gastrectomy for cancer.

BACKGROUND: Cancer of the gastric stump (CGS) after distal gastrectomy for cancer has not been characterized in a large study. The aim of this study was to investigate the clinicopathological features and outcome of CGS following distal gastrectomy for cancer. METHODS: Patients with CGS following distal gastrectomy for gastric cancer diagnosed between 1970 and 2002 were reviewed retrospectively. RESULTS: A total of 108 patients was identified. The median interval between the initial gastrectomy and resection for CGS was 7.5 (range 1-41) years. The depth of tumour invasion was T1 in 67 patients, T2 in 16, T3 in eight and T4 in 17 patients. Endoscopic mucosal resection was performed in 25 patients with T1 tumours. R0 resection was achieved in 103 patients. The overall 5-year survival rate was 53.1 per cent. The 5-year survival rates for patients with T1, T2, T3 and T4 disease were 76, 40, 13 and 9 per cent respectively. CONCLUSION: The outcome for patients with non-early CGS was poor. Early detection of CGS is important following distal gastrectomy for gastric cancer and strict surveillance is recommended for at least 10 years after the initial gastrectomy.

Adult↗
PubMed2006

Bite force, occlusal contact area and masticatory efficiency before and after orthognathic surgical correction of mandibular prognathism.

The purpose of this study was to evaluate bite force, occlusal contact area and masticatory efficiency before and after sagittal split ramus osteotomy in 27 patients with mandibular prognathism, in comparison with 27 control subjects with normal occlusion. Bite force and occlusal contact area were simultaneously measured with a computerized occlusal analysis system, the Dental Prescale system. Masticatory efficiency was estimated by a low-adhesive colour-developing chewing-gum system. The data were collected at initial medical consultation, immediately before surgery, and at 6 weeks, 3 months, 6 months, 1 year and more than 2 years after surgery. Both bite force and occlusal contact area of the patients before surgery were significantly less than those of the controls. Although all three parameters had improved after orthognathic surgery, the bite force and occlusal contact area did not reach the values of the controls within 2 years postoperatively; masticatory efficiency at 2 years after surgery drew near to control levels. Bite force correlated with occlusal contact area in the patients postoperatively, whereas masticatory efficiency did not correlate with either of the other two parameters. These results suggest that further adjustment of occlusion and mechanical advantage should be considered before the end of treatment.

Adolescent↗
PubMed2005

Adenovirus-mediated interferon alpha gene transfer induces regional direct cytotoxicity and possible systemic immunity against pancreatic cancer.

We previously demonstrated a characteristically high sensitivity of pancreatic cancer cells to interferon alpha (IFN-alpha) gene transfer, which induced a more prominent growth suppression and cell death in pancreatic cancer cells than in other types of cancers and normal cells. The IFN-alpha protein can exhibit both direct cytotoxicity and indirect immunological antitumour activity. Here, we dissected and examined the two mechanisms, taking advantage of the fact that IFN-alpha did not show any cross-species activity in its in vivo effect. When a human IFN-alpha adenovirus was injected into subcutaneous xenografts of human pancreatic cancer cells in nude mice, tumour growth was significantly suppressed due to cell death in an adenoviral dose-dependent manner. The IFN-alpha protein concentration was markedly increased in the injected subcutaneous tumour, but leakage of the potent cytokine into the systemic blood circulation was minimal. When a mouse IFN-alpha adenovirus was injected into the same subcutaneous tumour system, all mice showed significant tumour inhibition, an effect that was dependent on the indirect antitumour activities of IFN-alpha, notably a stimulation of natural killer cells. Moreover, in this case, tumour regression was observed not only for the injected subcutaneous tumours but also for the untreated tumours at distant sites. This study suggested that a local IFN-alpha gene therapy is a promising therapeutic strategy for pancreatic cancer, due to its dual mechanisms of antitumour activities and lack of significant toxicity.

Adenoviridae↗
PubMed2005

Manufacture of a 10-km-scale radius-of-curvature surface by use of a thin-film coating technique.

We tried a method of making a 10-km-class large-radius-of-curvature surface that would satisfy both low microroughness (0.1 nm rms) and low waviness (lambda/100) by forming a spherically curved film with a low-loss coating technique on a flat surface produced by mechanical (chemical) polishing. We obtained a SiO2 surface with a 10255 +/- 250-m radius of spherical curvature that had less than lambda/30 waviness and 0.4-nm micro-roughness over a 9-cm-diameter area.

Journal Article↗
PubMed2005

Threshold of regional cerebral blood flow for infarction in patients with acute cerebral ischemia.

Threshold of regional cerebral blood flow (rCBF) for cerebral tissue survival in relation to time was studied in patients with acute cerebral ischemia with xenon-enhanced computed tomography (XeCT). Case 1: A 58-year-old man with right hemiparesis, total aphasia and a high intensity area of 1 cm 2 in the left insula on diffusion weighted image underwent XeCT CBF study before and after intra-arterial local thrombolytic therapy (IALT) on the occluded middle cerebral artery (MCA) 4 hours and 7 hours after stroke onset, respectively. Case 2: A 65-year-old woman with recurrent transient ischemic attacks (TIAs) caused by severe stenosis of the left MCA underwent XeCT CBF study 5 hours after onset of the last attack. XeCT was conducted by 5-min wash-in method. In Case 1 the rCBF in the pre-IALT MCA territory was 4 to 19 ml/100 g/min. The area where rCBF in the post-IALT increased to above 15 ml/100g/min were saved, but the other area where it remained in the 9 to 14 ml/100 g/min evolved into infarct on subsequent CT scan/MR (magnetic resonance) imaging. The patient was discharged with only mild motor dysphasia. In Case 2 the left corona radiata showed rCBF of 7 ml/100 g/min and this area evolved into infarct on MR imaging. The patient was discharged home with right hemiparesis. Our results showed validity of the rCBF threshold in acute cerebral ischemia reported by Jones et al. Residual rCBF in the acute stage of cerebral ischemic stroke can predict the fate of the lesion.

Aged↗
PubMed2005

Emerging new alleles suggest high diversity of HLA-C locus.

Human leukocyte antigen (HLA)-C has only recently emerged as an important transplantation antigen and as a receptor for natural killer cells. Over the last few years, sequence-based typing (SBT) revealed the true diversity of HLA-C locus; however, the frequency at which new alleles are detected still remains high. During routine SBT of 3500 samples for the National Marrow Donor Program, we have identified 20 new HLA-C alleles reported in this article in 26 individuals. New variants have been characterized by direct sequencing of polymerase chain reaction product obtained by allele-specific amplification of potential new alleles. Most of the new alleles carry coding substitutions of residues located within the antigen-binding groove. The substitutions are predominantly located in the alpha2-helix which is consistent with the unique to HLA-C conservation of alpha1-helix. Seven new alleles, or 35%, have been identified in African Americans, two of them in three and four individuals each, suggesting that these alleles may not be rare. This observation reflects the fact that the minority groups, previously under-represented in the HLA research pools subjected to SBT, now begin to emerge as a main source of new HLA-C alleles. This study further confirms that HLA-C locus is at least as polymorphic as HLA-A and HLA-B.

Alleles↗
PubMed2005

The recombinant HLA-B*5518 allele supports the evidence of conserved haplotype association of rare alleles.

Allelic polymorphism of the major histocompatibility complex arises mostly from gene recombination. Intralocus gene recombination usually involves short fragments of DNA leading most commonly to single-nucleotide substitutions and rarely involves large fragments. Here, we report a new recombinant human leukocyte antigen (HLA)-B*5518 allele that has arisen via recombination of a large fragment of DNA spanning more than 70 nucleotides. During routine HLA typing of potential volunteer donors for the National Marrow Donor Program((R)), a new HLA-B allele was identified in two donors from Guam. The allele, B*5518, appears to be a product of recombination between B*5502 and B*40. Exons 1, 3, and 4 of the new allele belong to B*5502, whereas part of exon 2 belongs to one of B*40 alleles. Introns 1 and 2 appear to belong to B*55, suggesting that the recombination event may have occurred within the homologous parts of exon 2.

Alleles↗
PubMed2004

Significantly higher incidence of carotid atherosclerosis found in Japanese type 2 diabetic patients with early nephropathy.

We have tried to evaluate the clinical incidence of carotid atherosclerosis found in Japanese type 2 diabetic patients with early diabetic nephropathy. 123 diabetic patients with micro-albuminuria (group A) were investigated during 2-week hospitalization. As a control group, 50 diabetic patients without nephropathy (group B) were investigated. Carotid arteries were examined by B-mode ultrasonography (7.5 MHz), and peripheral arterial blood flow and pressure was examined at the same time with Doppler ultrasonography by a single examiner. Fasting blood samples and 24-h urine samples were taken to analyze biochemical data and urinary albumin excretion rate. In group A, 77 patients were found to have either carotid plaque lesions or increased thickness of carotid wall. And this was found significantly higher than in the control group B (18 cases, P < 0.01). To clarify the clinical risk factors for carotid atherosclerosis in diabetic patients with early nephropathy, 123 group A patients were divided into two groups with (group C, n = 76) or without carotid atherosclerosis (group D, n = 47) and comparative analysis was carried out. From this study, significantly higher incidence of carotid atherosclerosis was confirmed in the diabetic patients with early nephropathy. And it was suggested that the age, lipid levels, presence of hypertension would be important clinical risk factors for carotid atherosclerosis found in diabetic patients with early nephropathy.

Albuminuria↗
PubMed2004

Synergistic effect of cold and warm ischemia time on postoperative graft function and outcome in human liver transplantation.

Prolonged cold ischemia time (CIT) during graft preservation and warm ischemia time (WIT) during rewarming time have been reported to cause postoperative graft dysfunction after orthotopic liver transplantation (OLT). However, the effects of both CIT and WIT in combination on patient and graft survivals are not yet defined. The aim of this study was to determine whether simultaneously prolonged CIT and WIT were associated with early graft outcomes after clinical OLT. For analysis of liver graft survival within 90 days of OLT and postoperative graft function, 186 consecutive OLT cases were divided into four groups as follows: group A, CIT < 12 hours and WIT < 45 minutes; group B, CIT > 12 hours and WIT < 45 minutes; group C, CIT < 12 hours and WIT > 45 minutes; and group D, CIT > 12 hours and WIT > 45 minutes. The graft loss rates were 5.4% in group A, 9.8% in group B, 11.1% in group C, and 42.9% in group D. The mean highest aspartate aminotransferase (AST) value after OLT in group D (3352.3 +/- 569.4 U/L) was significantly greater than those in groups A (1411.7 +/- 169.2 U/L) and B (1931.3 +/- 362.6 U/L). The simultaneously prolonged cold and warm ischemia times significantly caused hepatic allograft injury and failure, suggesting some cumulative effects of CIT and WIT on postoperative graft function.

Adolescent↗
PubMed2004

HLA-Cw*1214 allele arisen via recombination between HLA-Cw*070201 and HLA-Cw*120201.

Allelic polymorphism of the major histocompatibility complex arises mostly from gene conversion. Intralocus gene conversion usually involves limited fragments of DNA, whereas recombination involving large fragments of DNA is considered to be a rare event. During routine sequencing-based typing of donors for the National Marrow Donor Program, a new HLA-C allele was identified in a Caucasian donor. The allele, HLA-Cw*1214, proved to be the product of recombination between HLA-Cw*070201 and HLA-Cw*120201. Exons 1, 2, the 3' end of exon 3 and exon 4 (with one mismatch) belong to HLA-Cw*120201, whereas part of exon 3 belongs to HLA-Cw*070201. Sequencing with primers based in exon 2 and exon 3 showed that intron 2 of the new allele also belonged completely to HLA-Cw*1202. The recombination event apparently occurred within exon 3 with the first point of recombination somewhere between codons 92 and 134 and the second one between codons 157 and 181.

Alleles↗
PubMed2004

Self-expandable metallic stents for palliation of malignant esophageal obstruction: special reference to quality of life and survival of patients.

SUMMARY. Self-expandable metallic stents (EMS) provide a common option for malignant esophageal stenosis because of the low complication rate and high dysphagia improvement rate. However, there are few studies on the functional duration of EMS and the extent of improvement of the quality of life. We retrospectively analyzed 18 patients who received EMSs in our division from 1996 to 2002. The median duration of possible food intake and the median survival period were 94.5 and 108 days. The median duration of domiciliary treatment was 56 days. Six of the 18 patients were not discharged from hospital after EMS insertion. The Karnofsky index was found to be a significant determinant of the feasibility of domiciliary treatment. One-third of the patients are incapable of obtaining the benefits of the palliative therapy. EMS deployment should be prudently selected for patients exhibiting low performance status.

Adult↗
PubMed2003

Cervical lymphadenectomy is beneficial for patients with carcinoma of the upper and mid-thoracic esophagus.

The role of cervical lymphadenectomy for thoracic esophageal cancer is controversial. This study evaluated the impact of cervical lymphadenectomy on the cervical lymph node metastasis (LNM) and survival rates of patients with esophageal cancer. We analyzed 199 patients who received radical esophagectomy with three-field lymphadenectomy. The overall 5-year survival rate was 49.4%. Cervical LNM was found in 36 (18.1%) out of the 199 patients. The 5-year survival rates of the patients with cervical LNM from upper and mid-esophageal cancers were 71.4% and 35.9%, respectively. However, none of the patients with cervical LNM from lower esophageal cancer survived more than 4 years after esophagectomy. The overall survival of patients with five or more metastatic nodes (5.9%) was significantly worse than that of patients with less than five positive nodes (45.5%). Cervical lymphadenectomy is beneficial for patients with carcinoma of the upper and mid-thoracic esophagus, and with less than five positive nodes.

Adult↗
PubMed2002

Role of interleukin-8 secreted from human oral squamous cell carcinoma cell lines.

Interleukin-8 (IL-8) is an important cytokine involved in tumor growth and angiogenesis in a variety of malignancies. Furthermore, matrix metalloptoteinases (MMPs) also play important roles in the invasion and metastasis of carcinomas including oral squamous cell carcinoma (OSCC). We studied whether IL-8 and MMPs participate in tumorigenesis and metastasis of OSCC. First, we investigated the gene and protein expressions of IL-8 and IL-8 receptor (IL-8R), and the effect of IL-8 on proliferation, migration and invasion of OSCC. Second, we thus also investigated the effect of IL-8 on MMP release in OSCC cells. OSCC cell lines NA and HSC-4 constitutively expressed IL-8 mRNA and secreted its protein in vitro. The production of IL-8 was significantly enhanced by the addition of tumor necrosis factor (TNF)-alpha and IL-beta, but not interferon (IFN)-gamma, granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-2. Flow cytometric analysis revealed the constitutive expression of both receptors of IL-8, IL-8RA and IL-8RB, in OSCC cell lines. The expression of IL-8 receptors in HSC-4 cells was stronger than that in NA cells. The intensity of IL-8RA expression was stronger than that of IL-8RB expression in each cell line. The expression of IL-8 receptors was not altered by the addition of cytokines such as TNF-alpha and IL-1beta. The conditioned medium containing IL-8 from OSCC cell lines induced migration and invasion of OSCC cells, but did not change cell proliferation. The differences in migrational and invasive ability between NA cells and HSC-4 cells were correlated with the expression intensity of IL-8 receptors in each cell line. Neutralizing antibodies to IL-8, IL-8RA and IL-8RB partially inhibited the chemotactic activity induced by conditioned medium. The expression of MMP-2, -7 and -9 was detected in culture supernatants from these OSCC cell lines. The expressions of MMP-7 protein and mRNA were enhanced by the addition of rIL-8, but that of other MMPs was not observed in a similar manner. These results suggest that IL-8 secreted from OSCC may contribute to the invasion of OSCC through the regulation of MMP-7 expression.

Carcinoma, Squamous Cell↗
PubMed2001

Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy.

TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of h approximately 5x10(-21)/sqrt[Hz], a signal-to-noise ratio of 30 is expected for gravitational waves generated by a coalescence of 1.4M-1.4M binary neutron stars at 10 kpc distance. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.

Astronomy↗
PubMed2001

Target gene therapy for alpha-fetoprotein-producing hepatocellular carcinoma by E1B55k-attenuated adenovirus.

Gene therapy using replication-competent adenovirus that selectively propagates in tumor cells may be an effective treatment for cancer. We developed an adenovirus that would be replication specific for hepatocellular carcinoma (HCC). Based on our finding that the E1B55k-deficient adenovirus was able to replicate in human primary hepatocytes, we therefore designed an adenovirus carrying E1A and attenuated E1B gene driven by the alpha-fetoprotein promoter (Adv-AFP-E1AdB), thus restricting the replication specificity in AFP-producing HCC. Replication of Adv-AFP-E1AdB in primary hepatocytes was practically negligible 4 days after infection. Although Adv-AFP-E1AdB replicated slowly in AFP-producing HCC, it efficiently destroyed HCC cells independent of their p53 status. Experiments were conducted in vivo using systemic administration of Adv-AFP-E1AdB and we observed tumor size reduction in nude mice having liver cancer. The use of replication-competent adenovirus deficient of the E1B gene coupled to an AFP-targeting strategy may be a safe and efficacious treatment for HCC.

Adenoviridae↗
PubMed2001

Effects of polyamines on DNA synthesis using various subcellular DNA polymerases extracted from normal rat liver, tumour-bearing rat liver, and tumour cells.

The effects of polyamines on DNA synthesis in vitro using various subcellular DNA polymerase fractions from normal and tumour-bearing rat livers, and tumour cells were investigated. When nuclear and mitochondrial DNA polymerase fractions were used, DNA synthesis on activated DNA was increased 3.5-8-fold by the addition of 20 mM putrescine or cadaverine. However, DNA synthesis was not stimulated by the addition of spermidine or spermine at any concentration tested. In contrast, DNA synthesis using the cytoplasmic DNA polymerase fraction was not stimulated at various concentrations of any of the four polyamines tested. The stimulatory effects of putrescine and cadaverine were absent when nuclear fractions from tumour-bearing rat liver or from tumour cells were used. In addition, in vitro DNA synthesis was not stimulated by 20 mM putrescine or cadaverine when nuclear extracts from the livers of rats administered putrescine subcutaneously were used. The specific activities of DNA polymerases extracted from tumour cells and tumour-bearing rat liver were already fully stimulated. These results suggest that DNA polymerases in tumour cells and tumour-bearing liver cells are stimulated by trapped putrescine produced in tumour cells and are thus no longer activated by exogenous putrescine.

Animals↗