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Biomedical subjects

W Yasui

Publications and source records attributed to W Yasui.

At least 181 records · Page 10Linked to original sources
PubMed1990

Growth factors in progression of human esophageal and gastric carcinomas.

Human esophageal and gastric carcinomas express multi-autocrine growth factors and hormones including epidermal growth factor (EGF), transforming growth factor (TGF)-alpha and beta, platelet-derived growth factor (PDGF), insulin-like growth factor (IGF) and sex hormones. Overexpression of EGF, TGF-alpha and EGF receptor (EGFR) by tumor cells is closely correlated with the tumor invasion and patient prognosis. This is substantiated by the facts that EGF and TGF-alpha act as autocrine growth factors and then induce the expression of mRNAs for multi-growth factors and their receptors (EGF, TGF-alpha, EGFR, ERBB2, PDGF). Moreover, they stimulate the expression of metalloproteinase genes suggesting that EGF and TGF-alpha successively evoke cascade phenomena which are most convenient for tumor progression, invasion and metastasis. On the other hand, multiple oncogene alterations take place in the process of tumor progression. HST-1 and INT-2 genes which is a member of fibroblast growth factor gene family, are amplified in approximately 50% of primary tumors and all the metastatic tumors of esophageal carcinomas. The amplification of ERBB2 gene in metastatic gastric carcinomas is detected more frequently than in primary carcinomas. Overexpression of multi-growth factor-receptor systems might lead to genetical alterations. Scirrhous gastric carcinoma has vast fibrous stroma with rapid and extensive growth and exhibits high malignancy. Its fibrous stroma may account for synchronous overexpression of EGF, TGF-alpha, PDGF, IGF and TGF-beta by tumor cells. Most of well differentiated adenocarcinomas show overexpression of p 185ERBB2 and coexpression of p 185ERBB2, and EGFR evidently correlates with high malignancy. In conclusion, the accumulation and interaction of several growth factors produced by tumor cells are necessary for the progression of human esophageal and gastric carcinomas. They may be attributed to genetic changes including activation of oncogenes, inactivation and deletion of anti-oncogenes and transcriptional regulatory sequences.

Epidermal Growth Factor↗
PubMed1990

Induction of growth factor-receptor and metalloproteinase genes by epidermal growth factor and/or transforming growth factor-alpha in human gastric carcinoma cell line MKN-28.

We examined the effects of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) on EGF receptor (EGFR) phosphorylation and the expression of mRNAs for oncogenes, growth factors, their receptors and metalloproteinase genes by MKN-28 gastric carcinoma cells which express EGF, TGF-alpha and EGFR genes. Both EGF and TGF-alpha stimulated EGFR phosphorylation, EGF and TGF-alpha induced FOS, MYC and ERBB-2 oncogene expression. Interestingly, EGF increased the expression of mRNAs for TGF-alpha and EGFR. On the other hand, TGF-alpha increased TGF-alpha mRNA but decreased the expression of mRNAs for EGFR and TGF-beta. Furthermore, mRNAs for interstitial collagenase, stromelysin and procollagen type I genes were also enhanced after treatment with EGF and TGF-alpha. These results indicate that EGF and TGF-alpha successively evoke cascade phenomena which favor tumor progression, invasion and extracellular matrix formation, acting as autocrine growth regulators for gastric carcinomas.

Carcinogens↗
PubMed1990

Depressed tubular adenoma of the stomach: pathological and immunohistochemical features.

We examined 12 depressed tubular adenomas of the stomach pathologically and immunohistochemically in order to clarify the difference between the depressed type and the elevated type. Depressed tubular adenomas showed shallow mucosal depression and, of the 12, nine were endoscopically diagnosed as early gastric cancer. Histologically, the adenoma cells showed dysplasia in varying degree and focal adenocarcinoma occurred in two adenomas measuring over 2 cm. The mean height of the adenoma glands was 0.63 +/- 0.31 mm in the 12 depressed adenomas and 1.32 +/- 0.43 mm in 44 elevated adenomas, while the mean heights of the subjacent mucosa were 0.18 +/- 0.19 mm and 1.07 +/- 0.71 mm, respectively. Thus, depressed adenomas resulted from paucity of the mucosa subjacent to the adenoma glands and the height of the adenomatous glands was half that found in the elevated type. Goblet cells, a variety of endocrine cells and lysozyme-containing cells were found in nine, nine and eight depressed adenomas, respectively, in variable numbers. Hyperplasia of these cells was also detected in depressed adenomas showing mild or moderate dysplasia. Immunohistochemical examination revealed no difference in the phenotypic expression of adenoma cells as between the depressed and the elevated type.

Adenoma↗
PubMed1990

Effect of epidermal growth factor on rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The effect of epidermal growth factor (EGF) on rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitro-soguanidine (MNNG) was studied. Male Wistar rats given MNNG for 30 weeks in drinking water (80 micrograms/ml) were treated with s.c. injections of human EGF (10 micrograms/kg, once daily) at various stages of the carcinogenesis. Four (30.8%) out of 13 rats treated with EGF immediately after cessation of the MNNG treatment had stomach tumors including one adenocarcinoma, one adenoma and two carcinoids. No stomach tumor was found in rats treated with MNNG alone or in those treated with MNNG and EGF for different periods such as synchronously for 10 weeks, for 30 weeks or throughout the experiment. These findings suggest a possible enhancing effect of EGF on stomach carcinogenesis in rats.

Animals↗
PubMed1990

[Molecular pathological diagnosis of cancer].

Molecular biological analysis plays an important role for understanding of cancer pathogenesis. For example, accumulation of oncogene and anti-oncogene changes is necessary for cancer development. Molecular pathology is defined as a study field examining clinical materials using molecular biological technique. Even though mechanisms of cancer development and progression has much complexity, molecular pathological findings give a crucial information on clinical medicine, as Ki-ras point mutation and certain allelic loss may convert colon adenoma into carcinoma. Overexpression of EGF/receptor in gastric cancer is a biologic marker for high malignancy. More accumulation of molecular pathological informations will provide a new approach for prospective molecular diagnosis.

Adenocarcinoma↗
PubMed1989

Minichromosome assembly accompanying repair-type DNA synthesis in Xenopus oocytes.

Minichromosomes were assembled by injection of circular DNA into the nucleus of Xenopus oocytes. We observed that, in the course of DNA supercoiling and chromatin assembly, a small percentage of the injected DNA molecules incorporated a radioactive precursor. This DNA synthesis was carried out by aphidicolin-sensitive DNA polymerase, and generated short repair-like patches covalently linked to the injected DNA. We found that the DNA thus repaired was rapidly supercoiled almost to completion within 15 to 30 min after injection, whereas 60 to 120 min were required to supercoil the intact, bulk DNA molecules. Such differential supercoiling kinetics was also observed when UV-damaged DNA was injected. Chromatin assembly, which was characterized by DNA fragment sizes protected from micrococcal nuclease digestion, was consistent with the rapid DNA supercoiling and proceeded more efficiently on the repaired DNA. These results indicate that there are at least two kinetically distinct ways of assembling minichromosomes in the oocyte nucleus, and that the repaired DNA molecules preferentially follow the faster pathway.

Animals↗
PubMed1989

Presence of multiple species of polypeptides immunologically related to transcription factor TFIIIA in adult Xenopus tissues.

Transcription of 5S RNA gene in Xenopus oocytes requires a 38 kDa transcription factor TFIIIA, which interacts with the 50 bp internal control region of the gene. We looked for TFIIIA-like polypeptides in the extracts of adult Xenopus tissues on the basis of their antigenic cross-reactivity to anti-TFIIIA antibody. Several species of polypeptides ranging from 30 to 50 kDa were found in kidney, stomach, liver and testis. Although these polypeptides reacted specifically to anti-TFIIIA antibody, proteolytic peptide mapping of three representative ones did not reveal any mutual similarities. They also seemed to be distinct from TFIIIA. Possible functions of these proteins are discussed.

Animals↗
PubMed1989

Characterization of early DNA synthesis in Xenopus eggs after injection of circular plasmid DNA.

Circular plasmid DNA is known to replicate when injected into unfertilized eggs of Xenopus laevis. We characterized early DNA synthesis which precedes the replication. Incorporation of a radioactive precursor into covalent closed circular DNA becomes detectable as early as 2 minutes after injection. Judging from the sensitivity to aphidicolin, replicative DNA polymerase alpha or delta is involved in this reaction. However, analysis of density-labeled product as well as detection of newly synthesized, unmethylated strands by restriction endonuclease DpnI digestion, both indicated that most if not all, of the synthesized DNA is present as short repair-like patches in the injected DNA molecules. They are present randomly in all the HaeIII fragments of injected DNA, and transcriptional activation of the 5S RNA gene inserted in the plasmid does not affect the distribution. Only a minor fraction of injected DNA is utilized for this reaction, and 12% of such DNA molecules are further chased into replicated progeny DNA. This efficiency of replication is nearly the same as that of bulk injected DNA which has not been subjected to the early DNA synthesis. We concluded that, despite the common use of replicative DNA polymerase, the early DNA synthesis and the subsequent DNA replication are mutually independent processes.

Animals↗
PubMed1989

Quantitation and subcellular localization of proliferating cell nuclear antigen (PCNA/cyclin) in oocytes and eggs of Xenopus laevis.

Proliferating cell nuclear antigen (PCNA/cyclin) is a 36-kDa polypeptide present in the nuclei of mitotically active cells. It is known to be involved in DNA replication through an association with DNA polymerase delta. We examined the total content as well as the subcellular distribution of PCNA in the oocyte and the egg of Xenopus laevis by employing immunocytological staining and immunoblot analysis. While oocytes are not capable of replicating chromosomes, PCNA is abundant in the nucleus (about 65 ng per nucleus). The oocyte cytoplasm, on the other hand, does not contain a significant quantity of this protein. The amount of total PCNA does not change appreciably during oocyte maturation and the subsequent stages of egg cleavage. Thus, PCNA belongs to a class of proteins which are stockpiled during oogenesis in order to be utilized later for early embryogenesis.

Animals↗
PubMed1989

The effect of phorbol esters on cell growth and epidermal growth factor receptor modulation in a human gastric carcinoma cell line TMK-1.

Tumor promoting phorbol esters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-dibutyrate (PDBu), significantly enhanced the growth of human gastric cancer cell line TMK-1, whilst activating protein kinase C. The time course of 125I-epidermal growth factor (EGF) binding to TMK-1 cells after TPA treatment showed a decrease in the number of EGF receptors on TMK-1 cells within 3 hr. Autophosphorylation of EGF receptor decreased in accordance with the decrease of EGF binding by TPA treatment. Scatchard plot analysis of TMK-1 cells after TPA treatment showed that high affinity EGF receptor disappeared at 3hr but the number of EGF receptors increased at 24 hr. These findings suggest that tumor promoting phorbol esters stimulate the cell growth through activation of protein kinase C and modification of EGF receptor of human gastric cancer cell line TMK-1.

Cell Division↗
PubMed1988

Interaction between epidermal growth factor and its receptor in progression of human gastric carcinoma.

The expressions of epidermal growth factor (EGF) and its receptor were studied immunohistochemically in a total of 156 gastric carcinomas; 26 early and 130 advanced. No EGF immunoreactivity was found in early carcinomas, while EGF-positive tumor cells were detected in 38 (29.2%) of the 130 advanced carcinomas. EGF receptor immunoreactivity was detected in one (3.8%) of the 26 early carcinomas and in 44 (33.8%) of the 130 advanced carcinomas, the incidence being significantly different (p less than 0.01). Out of the 130 advanced carcinomas, 17 (13.1%) had synchronous expression of EGF and its receptor and most of the tumors with strong expression of EGF were positive to EGF receptor. A significant correlation was observed between the depth of tumor invasion and EGF or its receptor immunoreactivity in tumor cells (p less than 0.05). Furthermore, a good correlation was demonstrated between the synchronous expression of EGF and its receptor and the depth of tumor invasion or the tumor staging. The incidence of cases with EGF in metastatic tumors was significantly higher than that in primary tumors (p less than 0.05). Patients with synchronous expression of EGF and its receptor had a far poorer prognosis than those without EGF and receptor.

Adenocarcinoma↗
PubMed1988

Expression of epidermal growth factor receptor in human gastric and colonic carcinomas.

The expression of epidermal growth factor (EGF) receptor was examined immunohistochemically in a total of 122 gastric and 61 colonic carcinomas, out of which 16 gastric and 8 colonic carcinomas were also examined by 125I-labeled EGF binding analysis and Western blotting. The values of EGF binding were 12.68 +/- 1.98 (SE; n = 16) fmol/mg protein in gastric carcinomas and 5.72 +/- 2.15 (n = 8) fmol/mg protein in nonneoplastic gastric mucosa, the difference being significant (P less than 0.01). In the colonic tissue, the binding capacities in carcinomas and nonneoplastic mucosa were 13.29 +/- 4.17 (n = 8) and 10.68 +/- 0.41 (n = 3) fmol/mg protein, respectively. Scatchard analysis of 125I-labeled EGF binding indicated a single class of receptors in gastric and colonic carcinomas with an apparent Kd value of from 111 to 277 (n = 4) and from 87.4 to 341 fM (n = 5), respectively, except for one gastric carcinoma having two classes of receptors (Kd = 15.9 and 896 fM). In Western blotting using monoclonal anti-EGF receptor antibody, various levels of EGF receptor expression were detected in 12 (85.7%) of the 14 gastric carcinomas and in 7 (87.5%) of the 8 colonic carcinomas. Immunohistochemically, EGF receptor immunoreactivity was detected in one (3.8%) of the 26 early gastric carcinomas, while it was observed in 33 (34.4%) of the 96 advanced gastric carcinomas, the incidence between the two being significantly different (P less than 0.01). In the colonic carcinomas, 47 (77.1%) of the 61 cases showed positive immunoreactivity to EGF receptor, which did not differ by histological type.

Carcinoma↗
PubMed1988

Phenotypic expression of human epidermal growth factor in foetal submandibular gland and pleomorphic adenoma of salivary gland.

The phenotypic expression of the human epidermal growth factor (EGF) was investigated immunohistochemically in human foetal submandibular glands from the 5th to 10th month of gestation, adult normal submandibular glands and 48 cases of pleomorphic adenomas. In foetal submandibular glands, both the terminal buds and primary ducts at the intermediate stage of gestation were positive for EGF, and in particular, the outer layer cells of primary ducts showed strong EGF-immunoreactivity. EGF-positive cells decreased as the gestational stage advanced and only ductal cells were weakly positive for EGF at the terminal stage of gestation. In the adult normal submandibular gland, weak immunoreactivity for EGF was restricted to ductal cells. However, 41 (86%) of the 48 pleomorphic adenomas had EGF-positive cells which were distributed among the ductal, chondroid and myxoid portion. No EGF-immunoreactivity was detected in the solid portion of pleomorphic adenomas. These results suggest that EGF may play an important role in the growth and differentiation of foetal cells as well as the proliferation of tumour cells in pleomorphic adenomas.

Adenoma, Pleomorphic↗
PubMed1987

Effects of a protein-free diet on the rat stomach.

The effects of a protein-free diet containing a mixture of free amino acids on the stomach were studied using male Wistar strain rats. In the forestomach, thickening of mucosa and hyperkeratosis appeared and papillomas frequently developed, but they did not occur in the control rats fed a semipurified diet. Mucous neck cells increased and parietal cells and chief cells decreased in the fundus. Goblet cells occurred in the antral glands, and intestinal metaplastic glands developed in the late stage of the experiment. The number of deoxyribonucleic acid-synthesizing cells in the glandular stomach was significantly higher than that of the control. Moreover, in the antrum, somatostatin-producing cells increased in the early stage and gastrin-producing cells decreased in the late stage. These results suggest that dietary protein might play a crucial role in the differentiation of gastric epithelium and the development of intestinal metaplasia in the stomach.

Amino Acids↗
PubMed1987

Expression of Ha-ras oncogene product in rat gastrointestinal carcinomas induced by chemical carcinogens.

The expression of Ha-ras oncogene product in rat gastrointestinal carcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or 1, 2-dimethylhydrazine (DMH) was studied by Western blotting and immunohistochemistry using anti-Ha-ras p 21 oncoprotein antibody. In Western blotting, high levels of c-Ha-ras p 21 were found in serially transplantable rat duodenal carcinomas induced by MNNG and rat colon carcinomas induced by DMH. Immunohistochemically, c-Ha-ras p 21 immunoreactivity was detected in 3 (16.7%) of 17 MNNG-induced stomach carcinomas and in 21 (63.6%) of 33 DMH-induced colon carcinomas, respectively. In the colon carcinomas, c-Ha-ras p 21 immunoreactivity in deeply invasive tumors was stronger than that in superficially invasive tumors and was expressed in all subserosal tumors. Moreover, all of the metastatic colon carcinomas had c-Ha-ras p 21 immunoreactive tumor cells. These findings suggest that c-Ha-ras p 21 expression plays an important role in tumor proliferation, invasion and metastasis of DMH-induced colon carcinoma.

Adenocarcinoma↗
PubMed1987

Immunohistochemical detection of c-myc oncogene product in human gastric carcinomas: expression in tumor cells and stromal cells.

c-myc protein p62 in human gastric carcinomas was studied by immunohistochemistry using an antiserum raised against the C-terminal portion of the human c-myc gene protein. No immunoreactivity of c-myc p62 was detected in tumor cells of 27 early carcinomas, while c-myc p62-positive tumor cells were observed in 51 (36.4%) of the 140 advanced carcinomas. Many stromal cells including macrophages and fibroblasts around the tumors showed various degrees of c-myc p62 immunoreactivity. Localization of c-myc p62 was predominant in the cytoplasm of tumor cells and stromal cells. The prognosis of patients with p62-positive stromal cells was significantly better than that of patients with p62-negative stromal cells.

Epidermal Growth Factor↗
PubMed1987

[A case of sweat gland carcinoma arising in a mature cystic teratoma of the ovary].

A case of sweat gland carcinoma arising in a mature cystic teratoma in a 63-year-old woman is reported. The patient was admitted with the complaint of a lower abdominal pain. Under the diagnosis of a mature cystic teratoma of the right ovary, the tumor was removed. Histologically, adenocarcinoma was found in the wall of the mature cystic teratoma. A part of the tumor showed a differentiation of the secretory portion and duct of the sweat gland. Histochemically, sialic acid containing mucoprotein was defected. Electron microscopically, the tumor cells were found to have secretory granules and intracytoplasmic canaliculi. Therefore, the tumor was diagnosed as a sweat gland carcinoma arising from a mature cystic teratoma.

Adenocarcinoma↗