Search PubMed⌕ Search

Biomedical subjects

M Onda

Publications and source records attributed to M Onda.

At least 19 recordsLinked to original sources
PubMed2000

Loss of heterozygosity at 3p24-p25 as a prognostic factor in breast cancer.

Differences in clinical course and biological characteristics among breast cancers will probably be explained ultimately by variations in the pattern of genetic alterations among the many genes that can play roles in carcinogenesis. Loss of heterozygosity (LOH) of a particular chromosomal region in a tumor, which presumably indicates loss of a growth-regulating 'tumor-suppressor' gene in that region, may represent a useful marker for postoperative prognosis. In earlier work we observed LOH at chromosomal regions 3p14-p21 and/or 3p24-p25 in a large proportion of breast cancers. To examine whether allelic losses in either of those regions might correlate with postoperative survival, we tested tumors from a cohort of 504 breast cancer patients for allelic losses of microsatellite markers in the relevant portions of chromosome 3p. Five years postoperatively, patients whose tumors had undergone LOH at 3p24-p25 were found to have borne significantly higher risks of mortality than women whose tumors retained both alleles at that locus; i.e. the 5-year mortality rate was 22% among patients with losses at 3p24-p25 vs. 9% with retentions of heterozygosity at that locus (P=0.0014). These data indicate that LOH at 3p24-p25 is a significant predictive factor for postoperative survival of patients who have undergone surgery for breast cancer.

Adult↗
PubMed2000

Identification of a 1-Mb common region at 16q24.1-24.2 deleted in hepatocellular carcinoma.

To identify the location of one or more putative tumor suppressor genes that may be involved in hepatocellular carcinoma (HCC), we examined 96 such tumors for their patterns of allelic loss at 21 microsatellite marker loci distributed along chromosome arm 16q. Allelic loss at one or more loci was observed in 58 (60%) of these tumors. Detailed deletion mapping identified a distinct commonly deleted region located within an interval flanked by D16S534 and D16S3091 at 16q24.1-24.2. By constructing a physical map consisting of a YAC contig across the region, the extent of the deleted region was determined to be less than 1 Mb. Among the tumors for which clinical data were available, allelic loss at 16q24.1-24.2 was more frequent in tumors arising from liver cirrhosis compared to HCCs arising from chronic hepatitis (30/42, 71%, vs. 13/33, 39%; P = 0. 0054). Additionally, allelic loss at 16q24.1-24.2 was frequently observed in small tumors and early-stage tumors as well as in tumors of more advanced phenotype.

Carcinoma, Hepatocellular↗
PubMed2000

Detection of circulating anti-p53 antibodies in esophageal cancer patients.

It has been reported that circulating anti-p53 antibodies (p53-Ab) in the serum are detected in some cancers. To investigate the usefulness of detecting p53-Ab, we measured the circulating p53-Ab in comparison with squamous cell carcinoma antigen (SCC-Ag) in patients with esophageal carcinoma. Serum specimens from 46 esophageal cancer patients (42 squamous cell carcinomas, 3 mucoepidermoid carcinomas and 1 basaloid squamous carcinoma) and 13 healthy subjects were studied. Serum p53-Ab was measured by an enzyme-linked immunosorbent assay. Surgically resected specimens from 43 patients were immunohistochemically stained for p53. Serum SCC-Ag was measured by a radioimmunoassay. The results were analyzed with the clinical data and outcome. Serum p53-Ab was detected in 13 (28%) of the 46 patients, but not in any of the healthy subjects. The positive rate was 0% (0/6) in stage I, 60% (3/5) in stage IIA, 30% (3/10) in stage IIB, 29% (7/24) in stage III and 0% (0/1) in stage IV. There was no difference in the outcome between the p53-Ab-positive and p53-Ab-negative patients. Immunohistochemically, 30 (70%) of the 43 specimens stained positively for p53. Serum p53-Ab was detected in 43% (13/30) of the patients with tumors which stained positively for p53. There was a close correlation between positivity for p53 immunostaining and positivity for p53-Ab (p<0.01). An elevated level of SCC-Ag was found in only 13%of the patients, and most patients positive for SCC-Ag already had advanced disease with lymph node metastasis and invasion to the adventitia. In conclusion, serum p53-Ab was detected in Japanese esophageal cancer patients at a frequency similar to that reported in Western countries. Serum p53-Ab may be a potentially useful molecular marker for detection and screening of esophageal cancer. Further studies of a large population may be required to elucidate the true diagnostic usefulness of measuring the serum p53-Ab.

Aged↗
PubMed1999

Tob2, a novel anti-proliferative Tob/BTG1 family member, associates with a component of the CCR4 transcriptional regulatory complex capable of binding cyclin-dependent kinases.

Human cDNAs encoding a novel member of Tob/BTG1 anti-proliferative family proteins were cloned. The putative protein product termed Tob2 consisted of 344 amino acids with high similarity to the Tob protein. The tob2 mRNA was 4.1 kb long and was ubiquitously expressed in human adult tissues, as was revealed by Northern blot hybridization. However, further in situ hybridization analysis showed a characteristic expression of the tob2 mRNA in oocytes, suggesting a unique role of Tob2 in oogenesis. Like the Tob protein, Tob2 inhibited cell cycle progression from the G0/G1 to S phases. Intriguingly, the amino-terminal half of Tob2 as well as that of Tob was associated with a human homologue of yeast Caf1, a component of the CCR4 transcription factor complex. Moreover, Caf1 was associated with cyclin dependent kinases. These data suggested that both Tob and Tob2 were involved in cell cycle regulation through their interaction with Caf1. Finally, the tob2 gene was mapped to human chromosome 22q13.1-q13.31.

3T3 Cells↗
PubMed1999

Reduction of the nonspecific animal toxicity of anti-Tac(Fv)-PE38 by mutations in the framework regions of the Fv which lower the isoelectric point.

Anti-Tac(Fv)-PE38, also called LMB-2, is a very active recombinant immunotoxin that has produced eight responses, including a durable clinical complete remission in a recently completed phase I trial of leukemias and lymphomas. Dose escalation was limited by liver toxicity. We have noted that the Fv of anti-Tac has an isoelectric point (pI) of 10.2. We hypothesize that the overall positive charge on the Fv portion of anti-Tac(Fv)-PE38 contributes to nonspecific binding to liver cells and results in dose-limiting liver toxicity. We have used a mouse model to investigate the basis of this toxicity and found that lowering the pI of the Fv of anti-Tac from 10.2 to 6. 82 by selective mutation of surface residues causes a 3-fold decrease in animal toxicity and hepatic necrosis. This change in pI did not significantly alter the CD25 binding affinity, the cytotoxic activity toward target cells, or antitumor activity, resulting in a 3-fold improvement in the therapeutic index. If this decreased toxicity occurs in humans, it should greatly increase the clinical utility of this immunotoxin.

ADP Ribose Transferases↗
PubMed1999

Somatic mutation of the PTEN/MMAC1 gene in breast cancers with microsatellite instability.

The extent to which microsatellite instability (MI) contributes to the etiology of breast cancer has not been established in any large-scale studies. We examined 528 samples of tumor DNA from patients with primary breast cancer for MI, using 14 polymorphic CA-repeat markers. The frequency of MI in these tumors was unexpectedly low (10/528, 1.9%). The ten MI+ tumors were analyzed for mutations in five potential target genes that contain simple repeat sequences (TGFBIIR, IGF2R, hMSH6, BAX and PTEN/MMAC1). A somatic insertion of an extra adenine in the (A)6 region at codon 321-323 (exon 8) of the PTEN/MMAC1 gene, leading to a frame-shift, was identified in one tumor. This observation represented the first documented instance of PTEN/MMAC1 alteration in a MI+ primary breast cancer.

Breast Neoplasms↗
PubMed1999

The usefulness of conducting investigations on intra-abdominal bacterial contamination in digestive tract operations.

A bacteriological study of 108 cases of gastrointestinal surgery was conducted by analyzing intra-abdominal bacterial contamination (IABC) and postoperative surgical site infections (SSI). We utilized an anaerobic porter to detect intra-abdominal bacterial infection and transport bacteria to the laboratory. The positive IABC rate was 42.9% for gastric cancer surgery, 22.6% for biliary tract surgery, and 85.7% for colorectal cancer surgery. Most cases of SSI were IABC-positive, and isolated bacterial species from the SSI were similar to those from the IABC. In colorectal cancer surgery, a preoperative chemical intestinal preparation and the prophylactic use of antibiotics had a major influence on the sensitivity of bacteria isolated from the SSI. These data suggest that prophylactic antibiotics should be chosen from among those to which bacteria from the IABC are highly sensitive, and that therapeutic antibiotics should be chosen from among those to which bacteria isolated from the SSI are highly sensitive. Finally, the exploration of IABC enables us to predict the incidence of SSI.

Adult↗
PubMed1999

Serum level of cytokeratin 19 fragment (CYFRA 21-1) indicates tumour stage and prognosis of squamous cell carcinoma of the oesophagus.

To determine the clinical efficacy of serum concentration of cytokeratin 19 fragment (CYFRA 21-1), sera from 66 patients with oesophageal squamous cell carcinoma were examined, and 54 surgically resected specimens were immunohistochemically stained for cytokeratin 19 (CK-19). The patients with positive CK-19 staining in the tissues of their carcinomas had significantly higher serum CYFRA 21-1 levels compared with those with negative CK-19 staining. When the cut-off value was defined as 2.0 ng/mL, CYFRA 21-1 had a higher positive ratio than that of either squamous cell carcinoma antigen (SCC-Ag) or carcinoembryonic antigen (CEA). Serum CYFRA 21-1 level increased significantly along with the clinical stages. In addition, serum CYFRA 21-1 level served as a prognostic factor for patients with oesophageal carcinoma after surgery, whilst SSC-Ag and CEA is not connected with the outcome. These findings suggest that the serum CYFRA 21-1 probably originated from the tumour tissue is an important marker for determining the stage and outcome of oesophageal carcinoma.

Adult↗
PubMed1999

Ret/PTC3 is the most frequent form of gene rearrangement in papillary thyroid carcinomas in Japan.

Rearrangements of the RET and TRK proto-oncogenes, which generate fusion oncogenes, are frequent in papillary thyroid carcinomas in Caucasian populations. To determine the spectrum of gene rearrangements in Japanese patients, we systematically examined 40 papillary thyroid carcinomas for all possible types of gene fusion events involving RET or TRK genes. RET rearrangements were found in ten tumors (25%): ret/PTC1 had occurred in two tumors, ret/PTC2 in one, ret/PTC3 in six, and a novel RET rearrangement in the remaining patient. In this last patient, the 5' novel sequence was fused in-frame to the RET amino acid sequence; thus, the fusion gene may encode a protein with a RET kinase domain at the carboxy terminus. The RET gene was fused to 5' donor sequences at the beginning of exon 12 in all ten tumors. No rearrangements involving the TRK gene were found in this panel of carcinomas. Our results indicated that constitutive activation of the RET by gene rearrangement is a frequent mechanism of papillary thyroid carcinogenesis in Japanese adults.

Adult↗
PubMed1999

Sclerotherapy plus ligation versus ligation for the treatment of esophageal varices: a prospective randomized study.

BACKGROUND: We devised a new combined method of endoscopic variceal ligation and injection sclerotherapy, namely, endoscopic scleroligation, for the treatment of esophageal varices. The aim of this prospective randomized trial was to compare endoscopic scleroligation with endoscopic variceal ligation alone with regard to efficacy, complications, variceal recurrence, and survival. METHODS: Fifty-one patients with cirrhosis and esophageal varices were randomly assigned to be treated by endoscopic scleroligation (n = 25) or endoscopic variceal ligation (n = 26). In the initial session in the endoscopic scleroligation group, endoscopic injection sclerotherapy was performed with injection of 5% ethanolamine oleate around the lower esophagus to obliterate the feeding veins. This was followed by endoscopic variceal ligation from the injection site to the most orad varix. In subsequent sessions, endoscopic injection sclerotherapy was performed with 1% polidocanol. In the endoscopic variceal ligation group, that procedure was performed in all treatment sessions. RESULTS: Both methods were equally effective in achieving complete eradication of esophageal varices. Among the cases in which complete eradication was achieved, the 1- and 3-year cumulative recurrence rates in the endoscopic scleroligation group (9.5%, 22.1%) were significantly lower than those in the endoscopic variceal ligation group (61.9%, 72.2%) (p < 0.01). The survival rates and incidences of treatment-related complications have been similar among patients treated by both methods. CONCLUSIONS: Endoscopic scleroligation is superior to endoscopic variceal ligation in preventing variceal recurrence.

Aged↗
PubMed1999

Detection of T cell apoptosis after major operations.

OBJECTIVE: To detect T cell apoptosis in reduced peripheral lymphocyte counts in patients having major operations. DESIGN: Prospective study. SETTING: University hospital, Japan. SUBJECTS: 11 patients having oesophagectomy and 5 having laparoscopic cholecystectomy. INTERVENTIONS: To investigate T cell apoptosis we detected DNA fragmentation using electrophoresis, and T-cell receptor-gamma (TCR-gamma) gene amplification using polymerase chain reaction (PCR) in serum. MAIN OUTCOME MEASURES: Peripheral lymphocyte count and DNA extracted from the serum preoperatively and on postoperative days 1, 3, 5, and 7. RESULTS: The lymphocyte count decreased significantly until day 5 and then increased in the patients who had had oesophagectomy. DNA fragmentation and PCR products for the TCRgamma variable region gene were found in the serum DNA of 10 patients until day 5. No DNA fragmentation or PCR products were found in the serum of patients who had had laparoscopic cholecystectomy. CONCLUSION: These results suggest that transient T cell apoptosis occurs after major operations.

Adult↗
PubMed1999

Escherichia coli mutM suppresses illegitimate recombination induced by oxidative stress.

DNA damage by oxidative stress is one of the causes of mutagenesis. However, whether or not DNA damage induces illegitimate recombination has not been determined. To study the effect of oxidative stress on illegitimate recombination, we examined the frequency of lambdabio transducing phage in the presence of hydrogen peroxide and found that this reagent enhances illegitimate recombination. To clarify the types of illegitimate recombination, we examined the effect of mutations in mutM and related genes on the process. The frequency of lambdabio transducing phage was 5- to 12-fold higher in the mutM mutant than in the wild type, while the frequency in the mutY and mutT mutants was comparable to that of the wild type. Because 7,8-dihydro-8-oxoguanine (8-oxoG) and formamido pyrimidine (Fapy) lesions can be removed from DNA by MutM protein, these lesions are thought to induce illegitimate recombination. Analysis of recombination junctions showed that the recombination at Hotspot I accounts for 22 or 4% of total lambdabio transducing phages in the wild type or in the mutM mutant, respectively. The preferential increase of recombination at nonhotspot sites with hydrogen peroxide in the mutM mutant was discussed on the basis of a new model, in which 8-oxoG and/or Fapy residues may introduce double-strand breaks into DNA.

Bacteriophage lambda↗
PubMed1999

Analysis of K-ras codon 12 point mutations using duodenal lavage fluid for diagnosis of pancreatic carcinoma.

We evaluated the diagnostic significance of the K-ras point mutations at codon 12 in duodenal lavage fluid (DLF) compared with pure pancreatic juice (PPJ). The DLF was easily and safely collected by injecting distilled water into the duodenum and then aspirating through the working channel of the endoscope during endoscopic retrograde cholangiopancreatography. Two types of DLF are collected this way: DLF 1 is collected just after insertion of the endoscope into the duodenum and DLF 2 is collected after cholangiopancreatography and/or collection of the PPJ using secretin. Analysis of K-ras mutations was performed using enriched polymerase chain reaction. In patients with pancreatic carcinoma (PC), K-ras mutations were detected in 14 of 23 (60.9%) in DLF 1, 16 of 21 (76.2%) in DLF 2, 14 of 20 (70.0%) in PPJ, and 19 of 21 (90.5%) in either DLF 1 or DLF 2. In patients with noncancerous pancreatic diseases consisting of pancreatic cystic diseases and chronic pancreatitis, the incidence of K-ras mutations was 2 of 21 (9.5%) in DLF 1 and 7 of 19 (36.8%) in DLF 2. These values were lower than that in PPJ, and there was significant difference between the incidence in DLF 1 and PPJ. These results suggested that DLF may provide a new and useful material for analysis of K-ras codon 12 point mutations in the diagnosis of PC.

Adenocarcinoma↗
PubMed1999

PTEN/MMAC1 mutations in hepatocellular carcinomas: somatic inactivation of both alleles in tumors.

Allelic loss of loci on chromosome 10q occurs frequently in hepatocellular carcinomas. Somatic mutations of the PTEN/MMAC1 gene on this chromosome at 10q23 were recently identified in sporadic cancers of the uterus, brain, prostate and breast. To investigate the potential role of PTEN/MMAC1 gene in the genesis of hepatocellular carcinomas, we examined 96 tumors for allelic loss on 10q and also for subtle mutations anywhere within the coding region of PTEN/MMAC1 gene. Allelic loss was identified in 25 of the 89 (27%) tumors that were informative for polymorphic markers in the region. Somatic mutations were identified in five of those tumors: three frameshift mutations, a 1-bp insertion at codon 83-84 in exon 4 and two 4-bp deletions, both at codon 318-319 in exon 8; two C-to-G transversion mutation, both at -9 bp from the initiation codon in the 5' non-coding region of exon 1. No missense mutation was observed in this panel of tumors. In most of the informative tumors carrying intragenic mutations of one allele, we were able to detect loss of heterozygosity as well. These findings suggest that two alleles of the PTEN/MMAC1 gene may be inactivated by a combination of intragenic point mutation on one allele and loss of chromosomal material on the other allele in some of these tumors.

Alleles↗
PubMed1999

In situ gene transfer and suicide gene therapy of gastric cancer induced by N-ethyl-N'-nitro-N-nitrosoguanidine in dogs.

Gene therapy could potentially revolutionize the treatment of gastrointestinal (GI) tract cancer. The aim of this study was to establish a practical method of gene transfer which would be applicable to human gastric cancer. Retrovirus or/and adenovirus vectors carrying the lacZ marker gene were transferred in situ by needle through an endoscopic biopsy channel into primary gastric cancer in six male beagle dogs that had been treated with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). In addition, an adenovirus vector carrying the herpes simplex virus thymidine kinase (Ad.CAGHSV-TK) gene was introduced in situ into cancer tissues in the stomach of three dogs, and the animals were treated with intravenous ganciclovir (GCV). Retrovirus-producing cells which expressed the lacZ gene were specifically localized to the injection site in the stomach. The lacZ gene was more widely transferred into the tumor by the adenovirus vector than by retrovirus-producing cells. Improvement of the needle used for gene transfer and the use of multiple injections per tumor led to more diffuse transfer of the vector into the tumor. The Ad.CAGlacZ gene was also transferred into regional lymph nodes of the stomach. Moderate to diffuse degeneration of the primary cancer tissues of the stomach was found after Ad.CAGHSV-TK/GCV gene therapy. Moreover, almost complete tissue degeneration was observed in the regional lymph nodes of the stomach. An adverse effect of HSV-TK/GCV gene therapy was acute hepatotoxicity, which was not found after Ad.CAGlacZ gene transfer, but was found after high-titer Ad.CAGHSV-TK gene transfer followed by GCV. These findings suggest that in situ gene transfer of a suicide gene followed by prodrug treatment may be applicable not only to primary tumors, but also to lymph node metastases of gastric cancer, though further study of both beneficial and adverse effects is required before clinical usage.

Adenoviridae↗
PubMed1999

Ultrastructural changes and immunohistochemical localization of nitric oxide synthase, advanced glycation end products and NF-kappa B in aorta of streptozotocin treated Mongolian gerbils.

To evaluate the relationship among the induction of nitric oxide synthase (NOS), advanced glycation end products (AGEs) and NF-kappa B for vascular damage in hyperglycemia, we injected Mongolian gerbils intravenously with 150 mg/kg streptozotocin (STZ) and observed over the next one year the resulting aortic changes by immunohistochemical and electron microscopical techniques. After STZ treatment, hyperglycemia was confirmed and body weight transiently decreased. Morphological observation revealed no remarkable changs in vascular endothelial cells or vascular smooth muscle cells in the aorta at one week after STZ administration. After 4 weeks increased collagen fibrils were observed in the pericellular spaces of media. At one year after STZ administration, increased collagen fibrils and thickened elastic fibers were found around the vascular smooth muscle cells with vacuolization and increased cytoplasmic organellae compared with non-treated animals of the same age. Immunohistochemically endothelial constitutive NOS (ecNOS) was localized in the endothelium of the aorta of Mongolian gerbils. At one year after STZ administration, the reaction products of iNOS, AGEs and NF-kappa B in vascular endothelial cells and smooth muscle cells were much more greatly increased than at one week and 4 weeks. After STZ administration, the localization of NOS, AGEs and NF-kappa B was observed in the aorta, which suggests these factors play important roles in the pathogenesis of vasculopathy in diabetes mellitus.

Animals↗