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M Obara

Publications and source records attributed to M Obara.

At least 37 records · Page 2Linked to original sources
PubMed1999

Expression of genes of type I and type II collagen in the formation and development of the blastema of regenerating newt limb.

We cloned cDNAs of alpha1(I) and alpha1(II) collagen, and studied their expression profiles in regenerating limbs of newts, Cynops pyrrhogaster. The expression of the alpha1(I) gene was markedly up-regulated at the early bud stage of the blastema. In situ hybridization experiments revealed that the alpha1(I) gene was expressed in not only mesenchymal cells of the blastema, but also the basal cells of the wound epidermis at the wound healing stage when the epidermal basement membrane was absent. This unique expression continued until 21 days (late bud stage), while the basement membrane began to form at 14 days. These results indicate biochemical differences between the wound and normal epidermis, and suggest the direct involvement of the former in the synthesis of blastemal matrices of type I collagen. Actually, immunohistochemistry revealed that type I collagen began to be deposited beneath the wound epidermis at 8 days, and accumulated there and around blastemal mesenchymal cells at 14 to 21 days. Undifferentiated mesenchymal cells associated with the amputated muscle fibers actively expressed the alpha1(I) gene. Mesenchymal cells in the central region of blastemas deposited type I collagen fibers around them. Concomitantly with the appearance of prechondrocytes, the alpha1(II) collagen gene became activated. The present study clearly shows that the expression of the genes of both type I and type II collagen in blastemal cells is temporally and regionally well-regulated in a cooperative manner. Dev Dyn 1999;216:59-71.

Amino Acid Sequence↗
PubMed1999

Mucin-producing tumors of the pancreas: clinicopathological features, surgical treatment, and outcome.

Mucin-producing tumors (MPTs) of the pancreas are increasingly being recognized. To evaluate the appropriate surgical treatment and predict the prognosis of MPTs, we performed a retrospective clinicopathological study in 51 patients, 27 with benign tumors and 24 with borderline/malignant tumors. Three of the malignant tumors showed stromal invasion and lymph node metastasis on histological examination. Of the 24 patients with borderline/malignant tumors, 2 died of MPTs and 4 died of other diseases. At the last follow-up, 35 patients were alive and well. The 5-year postoperative survival rate was 90% for patients with benign tumors, and 78% of these with borderline/malignant tumors. Five of the patients with borderline/malignant tumors had multicentric tumors. Three of these patients underwent resection of the rest of the pancreas, 5, 6, and 8 years, respectively, after the first operation. Extended radical resection is required for malignant MPT with invasion of the pancreatic stroma. We prefer to perform pancreatogastrostomy or Imanaga's procedure to allow examination of the body and tail of the pancreas by endoscopic retrograde pancreatography after resection of the pancreatic head. Careful follow-up for a long period may be the most prudent approach for detecting multiple MPTs in the residual pancreas after surgical treatment.

Adenocarcinoma, Mucinous↗
PubMed1999

Cell-type specific and thyroid hormone-dependent expression of genes of alpha1(I) and alpha2(I) collagen in intestine during amphibian metamorphosis.

Both the epithelium and the mesenchyme of the larval small intestine of anurans undergoes metamorphic conversion into the adult counterparts. The conversion of the mesenchyme has been poorly understood especially at the molecular level, whereas the changes of the epithelium have been extensively studied. The present study investigated the metamorphic changes of the mesenchyme of tadpoles of bullfrog, Rana catesbeiana, focusing on the expression of genes of type I collagen. By using the cDNA clones coding for a 1(I) and a 2(I) collagen as probes, expression of each collagen gene was examined. These genes were drastically up-regulated at the climax period of spontaneous metamorphosis, which was precociously mimicked by treating tadpoles with thyroid hormone. The increased expression of these genes at the climax stage was well correlated with the conversion of the thin larval mesenchyme to more thick and dense adult connective tissues of the intestine. In situ hybridization identified the fibroblasts that were actively expressing the collagen genes and, therefore, were thought to be responsible for the remodeling. These results strongly suggest that the expression of type I collagen genes is regulated during the intestinal remodeling in a cell-type specific and thyroid hormone-dependent manner.

Amino Acid Sequence↗
PubMed1999

The interaction of cellular fibronectin with collagen during fibroblast-mediated contraction of collagen gels.

In the first instance highly hydrated collagen gels contract to dense and compact gels when populated by fibroblasts. We previously reported the involvement of fibronectin (FN) in an early process of the collagen gel contraction, utilizing a specific monoclonal antibody dubbed A3A5 (MoAb-A3A5) that inhibits the gel contraction. This study was performed to further characterize the role of the epitope for MoAb-A3A5 in the interaction between fibroblasts and collagen fibrils. Although both cellular FN (cFN) and plasma FN (pFN) were reactive with MoAb-A3A5, the FN that actually participates in a process of the gel contraction was shown to be cFN. The gel contraction was significantly accelerated when fibroblasts were pretreated with excess amounts of cFN and was significantly inhibited when the collagen molecules were pretreated with excess cFN. Such effects of the pretreatments were not observed for pFN. The involvement of cFN, but not pFN, in the interaction of fibroblasts with collagen fibrils was additionally shown by the similar inhibitory action of cFN, but not pFN, on the spreading and elongation of fibroblasts on collagen fibrils. The epitope for MoAb-A3A5 was strongly suggested to be a new functional domain responsible for the interactions between fibroblasts and native collagen molecules. This was not the case for those with denatured one, because fibroblasts on collagen fibrils were not stainable with MoAb-A3A5, whereas the interactions on gelatin were stainable. The lack of the reactivity of fibroblasts on collagen fibrils toward MoAb-A3A5 was not a result of the absence of FN on the cell membrane, but seemed to be a steric hindrance to the access of the antibody.

Antibodies, Monoclonal↗
PubMed1998

Identification of the ligand binding site for the integrin alpha9 beta1 in the third fibronectin type III repeat of tenascin-C.

The integrin alpha9 subunit forms a single heterodimer, alpha9 beta1 that mediates cell adhesion to a site within the third fibronectin type III repeat of tenascin-C (TNfn3). In contrast to at least 3 other integrins that bind to this region of tenascin-C, alpha9 beta1 does not recognize the common integrin recognition motif, Arg-Gly-Asp (RGD). In this report, we have used substitution mutagenesis to identify a unique ligand recognition sequence in TNfn3. We introduced mutations substituting alanine for each of the acidic residues in or adjacent to each of the exposed loops predicted from the solved crystal structure. Most of these mutations had little or no effect on adhesion of alpha9-transfected SW480 colon carcinoma cells, but mutations of either of two acidic residues in the B-C loop region markedly reduced attachment of these cells. In contrast, cells expressing the integrin alphav beta3, previously reported to bind to the RGD sequence in the adjacent F-G loop, attached to all mutant fragments except one in which the RGD site was mutated to RAA. The peptide, AEIDGIEL, based on the sequence of human tenascin-C in this region blocked the binding of alpha9-transfected cells, but not beta3-transfected cells to wild type TNfn3. This sequence contains a tripeptide, IDG, homologous to the sequences LDV, IDA, and LDA in fibronectin and IDS in VCAM-1 recognized by the closely related integrin alpha4 beta1. These findings support the idea that this tripeptide motif serves as a ligand binding site for the alpha4/alpha9 subfamily of integrins.

Amino Acid Sequence↗
PubMed1998

A compact vacuum-ultraviolet beamline for synchrotron radiation photoelectron spectroscopy combined with an ion-scattering spectrometer, SORIS.

Apparatus for high-resolution synchrotron radiation photoelectron spectroscopy combined with high-resolution medium-energy ion scattering, named 'SORIS', has been developed for simultaneous investigations of electronic states and atomic structures on surfaces. For this purpose, a compact vacuum-ultraviolet beamline of photon energy from 5 to 700 eV has been designed for the small storage ring 'Aurora' installed at Ritsumeikan University. Owing to the small electron-beam size in the storage ring, an energy resolution E/dE of >5000 can be obtained.

Journal Article↗
PubMed1998

Determination of a normal level of serum CA125 in postmenopausal women as a tool for preoperative evaluation and postoperative surveillance of endometrial carcinoma.

In an attempt to determine a normal level of CA125 in postmenopausal women, CA125 levels of normal postmenopausal women (n = 36, 58.2 +/- 8.1 years) and postmenopausal women undergoing hormone replacement therapy (HRT) (n = 111, 56.8 +/- 6.1 years) were studied. A mean CA125 concentration of 10.0 +/- 3.8 U/ml was found in postmenopausal women without HRT and was significantly lower than that of postmenopausal women undergoing HRT (12.8 +/- 3.8 U/ml), indicating that the cutoff level of CA125 in postmenopausal women or women without reproductive organs should be estimated at a level lower than that conventionally accepted. A receiver operating characteristic (ROC) curve for a preoperative evaluation of myometrial invasion was analyzed in postmenopausal women with endometrial cancer (n = 110). A novel cutoff level of 20 U/ml of CA125 could detect myometrial invasion to more than one-half of the myometrium with sensitivity of 69.0%, specificity of 74.1%, positive predictive value of 58.8%, and negative predictive value of 81.6%. In addition, the distribution of CA125 levels was analyzed in patients who had undergone an operation for endometrial cancer more than 2 years earlier and as yet had no clinical evidence of recurrence of the disease. Ninety-six point two percent of 619 measurement values were lower than 20 U/ml. These results suggest that the novel CA125 level of 20 U/ml is clinically useful for preoperative evaluation and postoperative surveillance of endometrial carcinoma.

Aged↗
PubMed1998

Metastatic small cell lung cancer causing biliary obstruction.

We report a case with metastatic small cell lung cancer which first manifested with biliary obstruction due to metastasis. Prognosis of patients presenting with jaundice due to hepatic parenchyma involvement is thought to be poor. However, the patient was successfully treated with percutaneous transhepatic biliary drainage and combination chemotherapy with reduced dosage. We believe this to be the first such case report, despite the frequency of metastasis to the liver from small cell lung cancer.

Aged↗
PubMed1998

Combination therapy of active hexose correlated compound plus UFT significantly reduces the metastasis of rat mammary adenocarcinoma.

Synergistic effects of active hexose correlated compound (AHCC) extracted from mushroom on the treatment with UFT against mammary adenocarcinoma, SST-2 cells, in congenitally T cell-depressed spontaneously hypertensive rats (SHR) were observed. AHCC plus UFT had slight but significant effects on the growth of primary tumors. Pulmonary metastases were not inhibited by the treatment with AHCC plus UFT, whereas metastases to axillary lymph nodes (LN) were obviously inhibited. Combination of AHCC plus UFT showed similar synergistic anti-metastatic effects in SHR rats with accelerated pulmonary metastases following the surgical removal of the primary tumors. In vitro studies demonstrated that AHCC plus UFT enhanced the NK cell activity in tumor-bearing rats, whereas UFT alone depressed the NK cell activity. AHCC plus UFT also enhanced the NO production and cytotoxicity of peritoneal macrophages. In addition, AHCC restored the suppressed mRNA expression of interleukin-1alpha and tumor necrosis factor-alpha induced by the chemotherapy. Taken together, the combination of AHCC plus UFT brought about good therapeutic effects not only on primary tumor growth but also on reducing metastasis and these effects were mediated by host immunity which was restored or activated by AHCC. AHCC may be a good candidate for a biological response modifier.

Adenocarcinoma↗
PubMed1998

Pharmacokinetic study of an oral cephalosporin, cefdinir, in hemodialysis patients.

The pharmacokinetics of cefdinir were investigated in six hemodialysis patients. For the present study, two tests were carried out, one with 4 h of hemodialysis and the other without hemodialysis. Cefdinir was given orally to each patient in a dose of 100 mg, and blood was collected serially for 48 h after dosing in the test without dialysis and for 72 h in the test with dialysis. In the test without dialysis, the maximum plasma concentration (Cmax) was 2.36 +/- 0.53 micrograms/ml (mean +/- standard deviation) and the time to Cmax was 9.00 +/- 2.45 h. The terminal elimination half-life (t1/2) and area under the concentration-time curve (AUC) were 16.95 +/- 1.20 h and 69.05 +/- 14.84 micrograms.h/ml, respectively. In the test with dialysis, t1/2 during hemodialysis decreased approximately to one-sixth of that obtained in the test without dialysis, although t1/2 in the latter elimination phase did not differ from that in the nondialysis test. AUC was reduced to 43% of that in the test without dialysis. The fractional removal of cefdinir by hemodialysis was 61%. These findings indicate that clearance of cefdinir is prolonged in patients with renal failure, and cefdinir is well removed by introduction of hemodialysis, although t1/2 (during hemodialysis) and AUC were two and eight times higher than the data previously reported for healthy volunteers, respectively. The pharmacokinetic data suggest that 100 mg of oral cefdinir once a day would result in a sufficient concentration in plasma in hemodialysis patients, but this remains to be confirmed by multiple-dose studies.

Administration, Oral↗
PubMed1998

[A case of thymoma with pleural dissemination which was treated by pleurectomy with patient survival without recurrence for more than five years].

A 46-year-old woman was admitted to our hospital with chest pain. Chest X-ray and CT revealed an anterior mediastinal mass as well as several small masses attached to the left chest wall. Thymoma was diagnosed by percutaneous biopsy. The serum level of anti-acetylcholine receptor antibody was 30.3 pmol/ml. At operation, the thymoma was found left in the anterior mediastinum, extending to the upper lobe of the lung. There were also numerous tumors of various size in the left parietal pleura. Thymectomy, partial resection of the upper lobe of the lung and pleurectomy were performed. One month later, she developed myasthenia gravis. After a complete remission of myasthenia gravis brought about by anti-choline esterase therapy, the patient was treated with irradiation. She has been well for more than five years after the operation but her serum anti-acetylcholine receptor antibody level is still higher than normal.

Combined Modality Therapy↗
PubMed1997

Cloning and characterization of the full length cDNA encoding alpha2 type I collagen of bullfrog Rana catesbeiana.

The present study determined nucleotide sequences of the full-length cDNA of alpha2 chain of bullfrog type I collagen. Hybridization of a bullfrog cDNA library with human alpha1 type I collagen cDNA yielded a clone named 6A-1 which was 3449 bp long and lacked a 5' region of the gene. A 5' region containing the translation initiation site was amplified by the reverse transcription polymerase chain reaction using poly(A)+RNA from tadpole tail tissues as template, and oligonucleotides encoding the translation initiation region of mammalian fibrillar collagens and the Gly-X-Y repeat region of clone 6A-1 as primers. As a result we obtained a 1518 bp long clone Y31. A 355 bp long clone Y31-9 was produced by extending clone Y31 from its ATG codon to a 127 bp upstream region. Combining these three clones, the complete nucleotide sequence of the full-length cDNA was determined which contained 4692 bp as a whole and 4065 bp in the open reading frame. The comparison of its structure with known collagen cDNAs of various vertebrates showed that the cDNA obtained codes for alpha2(I) chain of bullfrog. Its deduced amino acid sequence revealed the complete conservation of seven cysteine residues in the C-propeptide and three lysine residues in the N-telopeptide through the helical domain. Northern blot analysis revealed that the thyroid hormone regulated the expression of alpha2(I) collagen in an organ-dependent manner: intense up-regulation in the back skin and intestine, weak and transient up-regulation in the liver, and initial down-regulation, but later up-regulation in the tail. Prolactin increased its expression in both the back skin and tail. These results suggested that the expression of bullfrog alpha2(I) collagen is cooperatively regulated by these two metamorphosis-regulating hormones.

Amino Acid Sequence↗
PubMed1997

A novel domain of fibronectin revealed by epitope mapping of a monoclonal antibody which inhibits fibroblasts-mediated collagen gel contraction.

The ability of cells to organize collagen fibrils is fundamental to a variety of processes found in embryogenesis, wound healing, fibrosis, and scar formation. We previously isolated a monoclonal antibody (mAb A3A5) which inhibits human fibroblast-mediated collagen gel contraction, an in vitro model producing the process of collagen morphogenesis. Human fibronectin (FN) has been shown to be the antigen of A3A5. The present study aimed at identifying the A3A5 epitope to reveal the mode of binding between collagen, FN, and fibroblasts in the process of gel contraction. The epitope was sought in FN fragments obtained by pepsin digestion and in recombinant FN fragments expressed in Escherichia coli by determining their immunological reactivity with A3A5, and was identified as a short segment consisting of the fourth through the amino half of the fifth FN type III. We propose a new functional domain of FN which plays a crucial role in the binding of fibroblasts to collagen fibrils and is involved in collagen morphogenesis.

Amino Acid Sequence↗
PubMed1997

A new synthetic lipid A analog, ONO-4007, stimulates the production of tumor necrosis factor-alpha in tumor tissues, resulting in the rejection of transplanted rat hepatoma cells.

ONO-4007 is a new synthetic lipid A derivative with low endotoxic activities. We have examined the therapeutic effects of ONO-4007 on rat hepatocellular carcinoma KDH-8 cells, rat fibrosarcoma KMT-17 cells and rat mammary adenocarcinoma SST-2 cells in vivo. Multiple systemic i.v. administration of ONO-4007 was performed on days 7, 14 and 21 after tumor implantation of KDH-8 and SST-2 cells, and on days 5, 10 and 15 after tumor implantation of KMT-17 cells. ONO-4007 showed significant therapeutic effects on KDH-8 cells; by the administration of ONO-4007 (2.5 mg/kg) 70% of rats were cured and by the administration of ONO-4007 (5 mg/kg) 50% of rats were cured. Furthermore, the ONO-4007 treatment prolonged the mean survival time of KDH-8-bearing rats. However, ONO-4007 had no effect on KMT-17 and SST-2 cells, and it had no direct effect on the growth of KDH-8 cells in vivo. Albeit the stimulation with ONO-4007 induced mRNA expressions of interleukin (IL)-1alpha, IL-6 and tumor necrosis factor (TNF)-a, those of IL-2, IL-4, IL-10 and interferon (IFN)-gamma were not induced. Using a bioassay, we found that the production of TNF-alpha in the tumor tissues was induced by ONO-4007 in a dose-dependent manner. KDH-8 cells were sensitive to human natural TNF-alpha in vitro. However, KMT-17 and SST-2 cells were resistant against TNF-alpha in vitro. These results suggest that ONO-4007 is therapeutically useful for the treatment of TNF-alpha-sensitive tumors.

Adenocarcinoma↗
PubMed1997

The mechanism of locally enhanced production of tumor necrosis factor-alpha in tumor tissues by the administration of a new synthetic lipid A analog, ONO-4007, in hepatoma-bearing rats.

ONO-4007 is a new synthetic lipid A analog with low endotoxic activities. We previously found that ONO-4007 induced the production of tumor necrosis factor (TNF)-alpha in rat hepatoma KDH-8 tumor tissues and brought about the regression of transplanted KDH-8 cells. By contrast, ONO-4007 did not induce TNF-alpha production in spleens and sera 90 min after treatment. In the present study we attempted to elucidate how ONO-4007 induces TNF-alpha production in tumor tissues locally. We found that extracellular matrix including gelatin, fibronectin and Matrigel did not induce TNF-alpha production in splenocytes treated with ONO-4007 in vitro. However, splenocytes co-cultured with cKDH-8/11 tumor cells in the presence of ONO-4007 produced more TNF-alpha than splenocytes cultured by themselves in the presence of ONO-4007. The stimulation of cKDH-8/11 cells in the presence of ONO-4007 for splenocytes to produce TNF-alpha depended on the type of contact between the cells. The cKDH-8/11 cells fixed in formalin were not able to induce TNF-alpha production of splenocytes even in the presence of ONO-4007. However, syngeneic fibrosarcoma cell line KMT-17/A3, allogeneic hepatocellular carcinoma cell line LDH and rat lung endotherial cell line RLE induced TNF-alpha production in splenocytes, but their stimulation was weaker than that of cKDH-8/11. The soluble form of the cKDH-8/11 cell membrane did not stimulate splenocytes to produce TNF-alpha in the presence of ONO-4007. cKDH-8/11 cells did not stimulate the splenocytes devoid of macrophages to produce TNF-alpha in the presence of ONO-4007.

Animals↗
PubMed1997

Therapeutic effects of a new synthetic lipid A analog, ONO-4007, on rat hepatoma KDH-8 depend on tumor necrosis factor-sensitivity of the tumor cells.

ONO-4007 is a new synthetic lipid A derivative with low endotoxic activities. ONO-4007 was effective against KDH-8, a tumor necrosis factor (TNF)-sensitive rat hepatoma cell line, but neither effective against KMT-17, a TNF-resistant rat fibrosarcoma cell line, nor SST-2, a TNF-resistant rat mammary adenocarcinoma cell line. We have established two sublines from KDH-8 to further examine the therapeutic mechanisms of ONO-4007 in vivo: TNF-sensitive KDH-8/YK and TNF-resistant cKDH-8/11. The two sublines equally proliferated in vitro. Multiple systemic i.v. administration of ONO-4007 was performed on days 7, 14 and 21 after tumor implantation. Although treatment with ONO-4007 had no effect on the growth of cKDH-8/11 in WKAH rats in vivo, 60% of KDH-8/YK-bearing rats treated with ONO-4007 survived. The administration of ONO-4007 brought about significant therapeutic effects on KDH-8/YK-bearing rats but not on cKDH-8/11-bearing rats. These results suggest that ONO-4007 is therapeutically useful for the treatment of TNF-alpha-sensitive tumors.

Adenocarcinoma↗