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Biomedical subjects

K Miyazaki

Publications and source records attributed to K Miyazaki.

At least 163 records · Page 9Linked to original sources
PubMed2000

Marked increase of trypsin(ogen) in serum of linitis plastica (gastric cancer, borrmann 4) patients.

Linitis plastica, or Borrmann 4 gastric cancer, shows very poor prognosis, and the reason has not been understood. In the present study, we examined serum levels of trypsin(ogen) in 44 gastric cancer patients, including 17 early gastric cancer, 18 non-Borrmann 4 advanced gastric cancer, and 9 Borrmann 4 gastric cancer, by using the RIA gnost Trypsin kit (Hoechst Japan, Tokyo, Japan), which was expected to detect trypsin-1, trypsin-2, trypsinogen-1, and trypsinogen-2 in sera. The trypsin(ogen) concentration was much higher in the patients with linitis plastica than in the other gross types of gastric cancer. Hypertrypsinemia was identified in approximately 60% of advanced gastric cancer cases. Lymph node involvement, liver metastasis, or poorly differentiated adenocarcinoma is an important factor of hypertrypsinemia. The serum trypsin(ogen) level in linitis plastica patients was 3484.4 +/- 2319.7 ng/ml (mean +/- SD), which was significantly higher not only than that of the early gastric cancer (384.1 +/- 92.1) but also the stage IV gastric cancer patients (578 +/- 440.4), excluding those with linitis plastica. The elevated serum trypsinogen level in linitis plastica patients may be related to the malignant behavior of this type of cancer cell. Serum trypsin(ogen) of linitis plastica shows significantly higher concentrations than do the other types of advanced gastric cancer. Therefore, serum concentration of trypsin(ogen) might be a good marker of gastric cancer of linitis plastica.

Humans↗
PubMed2000

[Clinical experience with assisted reproductive technology along the development of micro fertilization].

In 1993 we had the first success of micro fertilization in our clinic. The method by partial opening of oocyte zona pellucida initially used achieved a fertilization rate per egg of only 26.7%. Although transfer of sperm under the zona raised the fertilization rate to 39.2%, the new method involved problems such as polyspermy, which represented approximately 30% of the total fertilization rate. In addition, use of this method was limited to patients meeting several conditions. In 1994, we had a successful case of pregnancy after intracytoplasmic sperm injection (ICSI). The ICSI method resulted in a fertilization rate of about 70%, and has solved the problem of polyspermy. Fertilization of eggs has become possible using immotile sperm, and the technique of microsurgical epididymal sperm aspiration (MESA) and testicular sperm extraction (TESE) has been established. Clinical data have confirmed that a fertilization rate by frozen sperms is not lower than that by fresh sperms. Sperm can be stored frozen after MESA or TESE and therefore are surely available when needed, allowing to avoid spoiling retrieved eggs. No difference in fertilization rate was found between conditions needing micro fertilization or sperm recovery methods. No difference in pregnancy rate was shown between treatment cycles. Recent reports show improved pregnancy rates using techniques such as transferring a frozen embryo after endometrical adjustment. Further development in assisted reproductive technology is anticipated.

Female↗
PubMed2000

[Fine-structural analysis of hyper-acute rejection in cardiac xenotransplantation].

Hyper-acute rejection after cardiac xenotransplantation has been extensively studied, but its morphological changes have not been adequately elucidated yet. We investigated the morphological changes in two kinds of cardiac xenotransplantation models, guinea pig hearts in rats and hamster hearts in sensitized rats, in terms of histology, immunohistochemistry. TdT-mediated dUTP nick-end labeling (TUNEL) and ultrastructure. Four guinea pig hearts were heterotopically transplanted to rats and four hamster hearts to sensitized rats by the modified technique of Ono and Lindsey. In the hamster-to-rat model, the rats were treated with a hamster skin tissue at two weeks before transplantation. Rejection of the grafts was diagnosed from cessation of the graft heart contraction. Immunohistochemically, C3 was deposited along all vessels including coronary vessels, arterioles, venules and capillaries, and IgM was deposited along major vessels in the guinea pig grafts; it was vice versa in the hamster grafts. In the guinea pig grafts, TUNEL showed positive staining in endothelial cells and myocytes, whereas no positive signal was shown in the rejected hamster hearts. Transmission electron microscopy revealed platelet aggregations in the vessels of guinea pig-to-rat and hamster-to-sensitized rat cardiac xenografts. In the guinea pig-to-rat cardiac xenografts, capillary walls were thin with a high electron density and the number of pinocytotic vesicles was reduced. Also several nuclei of the endothelial cells showed pyknosis and some nuclei were fragmented. On the other hand, these findings were not typical in the hamster-to-sensitized rat cardiac xenografts. In conclusion, this study revealed thromboembolism of capillaries and impairment of the endothelial cells in the hyper-acutely rejecting cardiac xenografts. Apoptosis of myocytes and endothelial cells was shown to be involved only in the hyper-acutely rejecting guinea pig-to-rat cardiac xenografts. These results indicated variability in hyper-acute rejection.

Animals↗
PubMed2000

Neonatal repair of anomalous origin of the right pulmonary artery from the ascending aorta. A case report and review in the literature.

A seven-day-old neonate presented with respiratory distress and an early diagnosis was achieved through the echocardiographic studies which successfully visualized an anomalous origin of the right pulmonary artery arising from the ascending aorta. Subsequently a surgical correction with direct anastomosis of the right pulmonary artery to the main pulmonary trunk was accomplished in the neonatal period. The English literature in the last two decades is reviewed to discuss the characteristics, the diagnosis and treatment of neonatal cases with anomalous origin of the right pulmonary artery arising from the ascending aorta.

Angiography↗
PubMed2000

Biological response to expandable metallic stents implanted into the portal vein. A histomorphometric study.

BACKGROUND: This study was undertaken to investigate the biological response to an expandable metallic stent implanted in the canine portal vein with a special reference to the histomorphometric contribution of cellular and acellular elements to the intimal and medial growth. METHODS: In 11 dogs, the Gianturco Z stent was placed into the portal vein and was harvested at intervals of 4 (n=6) and 12 weeks (n=5). In 6 dogs, the normal portal vein was harvested and used as a control. The specimens were subjected to histomorphometric examination. RESULTS: Mean intimal/medial thickness and total intimal/medial area significantly increased progressively by 12 weeks. Collagen intimal/medial area also significantly increased progressively by 12 weeks, while smooth muscle intimal/medial area significantly increased at 4 weeks but did not change from 4 weeks to 12 weeks. Collagen density tended to increase at 4 weeks and significantly increased at 12 weeks, while smooth muscle density significantly decreased at 4 weeks and continued to decrease at 12 weeks. CONCLUSIONS: The total area or mean thickness of the intima and media of the stented portal vein continued to increase by 12 weeks after stent placement. This phenomenon appeared to be due to proliferation of smooth muscle cells followed by accumulation of collagen.

Animals↗
PubMed1999

Identification of cell-binding site of angiomodulin (AGM/TAF/Mac25) that interacts with heparan sulfates on cell surface.

Angiomodulin (AGM/TAF/mac25) is a 30-kDa glycoprotein that was identified as an integrin-independent cell adhesion protein secreted by human bladder carcinoma cells. AGM is highly accumulated in small blood vessels of tumor tissues. In the present study, we attempted to identify the cell surface receptor and the cell-binding site of AGM using ECV-304 human vascular endothelial cells and BALB/c3T3 mouse fibroblasts. Heparin, heparan sulfate, and dextran sulfate, but not chondroitin sulfate, inhibited both adhesion of the two cell lines to AGM-coated plates and binding of AGM to these cells. Treatment of cells with heparinase, but not chondroitinase, inhibited both cell adhesion to AGM and AGM binding to cells. These results strongly suggested that heparan sulfates are the major receptor for AGM. Furthermore, we determined a 20-amino acid sequence within AGM molecule as its major cell-binding site. The synthetic peptide for the cell-binding sequence showed cell adhesion activity comparable to that of AGM, and the activity was inhibited by heparin and heparan sulfate. The peptide competitively inhibited cell adhesion to AGM and the binding of AGM to cells. These results indicated that AGM binds to cells through interaction of the identified cell-binding sequence with heparan sulfates on cell surface. It was also found that the heparan sulfate-binding peptide inhibited the formation of capillary tube-like structures of vascular endothelial cells in culture.

Animals↗
PubMed1999

Overexpression of laminin gamma2 chain monomer in invading gastric carcinoma cells.

Laminin (LN)-5, a heterotrimer of alpha3, beta3, and gamma2 chains, has been suggested to be involved in tumor cell invasion. The present immunohistochemical study investigated the distribution of the LN gamma2 chain in 48 different human gastric adenocarcinomas. The immunohistochemical analysis showed two distinct patterns of LN gamma2 chain expression: (a) extracellular deposition; and (b) cytoplasmic accumulation. The extracellular deposition of the LN gamma2 chain was typically observed at neoplastic basement membranes of well-differentiated adenocarcinomas. The immunoreactivity was continuous along tumor basement membranes in these tumors but was irregular and diffuse in poorly differentiated carcinomas. These tumor cells coexpressed the LN alpha3 and beta3 chains, suggesting that the LN gamma2 chain was deposited as the LN-5 complex. In contrast, tumor cells at the invading fronts showed strong cytoplasmic staining for the LN gamma2 chain without any detectable signal for the LN alpha3 or beta3 chain in both well- and poorly differentiated carcinomas. On the other hand, in vitro analysis by two-dimensional SDS-PAGE demonstrated that human gastric carcinoma cells secrete a high level of LN gamma2 chain monomer in addition to the LN-5 complex into culture medium. These results indicate that the LN gamma2 chain can be secreted as a single subunit and might be involved in tumor cell invasion.

Adenocarcinoma↗
PubMed1999

Functional mutation of DNA polymerase beta found in human gastric cancer--inability of the base excision repair in vitro.

DNA polymerase beta (polbeta) is one of mammalian DNA polymerases and is known to be involved in a G:T/G:U mismatch repair. In order to investigate an involvement of this enzyme in a base excision repair, we searched a mutation of human polbeta in human gastric cancer and studied a function of the mutation. We observed cancer-specific missense mutations in 6 of 20 samples. All of these mutations were, however, heterozygous. We further analyzed the base excision repair activity of these mutants to know whether these mutants cause an error of mismatch repair. One of these mutants, which resulted in an amino acid substitution of Glu for Lys at codon 295, showed an inhibitory effect by in vitro base excision repair assay, suggesting that this mutation might play some role in carcinogenesis of the gastric mucosa.

Aged↗
PubMed1999

Critical amino acid substitutions in the Src SH3 domain that convert c-Src to be oncogenic.

The Src homology 3 (SH3) domain, originally identified in v-Crk, plays an important role in signal transduction. The comparative study with c-src has revealed that v-src oncogene of Schmidt-Ruppin strain of Rous sarcoma virus has three point mutations in its SH3 domain and one in the upstream of SH3. To assess the role of these mutations, each of the single mutations was introduced into c-Src by oligonucleotide-directed mutagenesis and its effect on cell transformation was examined. While variant Src proteins that carry each one of single mutations could not transform cells, double mutation at positions 95 and 117 converted c-Src to be oncogenic and active in kinase. An additional mutation at position 124 together with one at 95 and 117 further activated Src kinase. By use of GST-fusion forms of v-Src SH3 and c-Src SH3, we found that these mutations in SH3 suppressed the binding of SH3 with c-Src protein, possibly with a linker region, while v-SrcSH3 retained the ability to bind a subset of cellular protein to the level similar to those of c-SrcSH3. Taken together, our results suggest that point mutations accumulated in SH3 region can activate, in concert, Src kinase by relaxing the interaction between SH3 and the linker region and subsequently convert Src to be oncogenic.

Amino Acid Substitution↗
PubMed1999

Regression and prevention of autochthonous tumors induced by 3-methylcholanthrene after injection of a T-cell receptor alpha /beta positive and CD4/CD8 double negative T-cells.

Both the therapeutic and preventative effects of a murine T-cell line, tMK-2, with T-cell receptor (TCR) alpha/beta positive and CD4-/8- double negative (DN) phenotype against autochthonously tumors induced by subcutaneous (s.c.) injection of 3-methylcholanthrene (MC) were examined. Complete regression of the tumor was observed when administration of tMK-2 cells was begun on tumors 5 mm in diameter. The tumor mass in five out of five mice was reduced in size after the administration of tMK-2 cells regardless of the routes of administration: s.c. injection of tMK-2 cells (5 x 10(7) cells) once a week around tumors, intraperitoneal (i.p.) injection (5 x 10(7) cells), or intravenous (i.v.) injection (1 x 10(7) cells). The tumors regressed to the status of a scar within 1 month of initial injection, and this status was maintained throughout the remainder of the 3 months period of tMK-2 cell injection. One month after discontinuation of tMK-2 cell administration, the diameter of the tumors had not increased regardless of the route of injection. The control groups consisted of either untreated mice, mice with i.v. injection of 1 microg of recombinant murine interleukin (IL)-12 once a week, or mice with s.c. injection of autologous splenocytes (5 x 10(7)) from BALB/c mice once a week. Continuous growth of tumors was observed in each group and all control mice died due to bleeding ulcerations of the tumors. Tumor development was effectively prevented when tMK-2 cells were administrated 1 week after the s.c. injection of MC. In the groups receiving s.c., i.p., and i.v. injection of tMK-2 cells, no MC-induced tumors developed, whereas four out of five of the control mice developed autochthonous tumors. The tMK-2 cells also exerted in vitro NK-like cytotoxic activity, and their killing activity was strongly increased in the presence of both IL-2 and IL-12. These results suggest that the injected T-cells with TCR alpha/beta positive and CD4- /8- DN phenotype and NK-like activity are important in the therapy as well as the prevention of tumor development.

Animals↗
PubMed1999

Serum-free culture conditions for analysis of secretory proteinases during myogenic differentiation of mouse C2C12 myoblasts.

We have been studying extracellular proteins such as proteinases and attachment factors under serum-free culture conditions. A number of studies on myogenesis using an in vitro culture system have reported that proteinases and ECM components play significant roles in muscle differentiation. However, most of the studies were performed in the presence of serum. Serum is abundant in the aforementioned proteins and its use in serum-free culture affects many cellular functions significantly. In this study, we tried to establish serum-free culture conditions for analyzing extracellular proteins involved in mouse myogenic differentiation. By evaluating media, supplements, and procedure of cell inoculation under serum-free conditions and by comparing the resultant conditions with conventional conditions on differentiated characteristics of the cells, it was revealed that serum-free Dulbecco's modified Eagle's medium/Ham's F-12 plus insulin more efficiently supported myogenesis morphologically and biochemically than conventional 2% horse serum-containing culture and that secretory proteinases obtained from our serum-free culture were different from those obtained utilizing conventional serum-free cultures in their activities and patterns. Since our serum-free medium consists of simple components, the medium is low cost and easy to prepare. Furthermore, the results suggest that our culture conditions are superior to conventional conditions biochemically and morphologically and will provide more precise and accurate information on extracellular proteins involved in myogenesis.

Animals↗
PubMed1999

DNA mismatch repair deficiency in curatively resected sextuple primary cancers in different organs: a molecular case report.

A male patient synchronously or metachronously underwent six curative resections after diagnoses of cancers in the rectum, urinary bladder, stomach, colon, liver and lung. Five cancers, excluding early colon cancer, were analyzed for instability in seven microsatellite markers and in transforming growth factor beta type II receptor, insulin-like growth factor II receptor and BAX. All analyzed cancers had replication errors and instability in at least one target gene. These results suggest that abnormal DNA mismatch repair system plays a major role in the occurrence of multiple primary cancers in this case.

Adenocarcinoma↗
PubMed1999

Estradiol-17beta measurement in women receiving conjugated estrogens. Dissociation between two commercial methods.

To investigate problems associated with measurement of estradiol-17beta (E2) in hormone replacement therapy (HRT), two commercial immunometric methods (Coat-A-Count E2 and Immulyze E2) were used to assay E2 concentrations and the two results were expressed as E2 ratios. Samples were obtained from 97 Japanese women receiving HRT and 168 unmedicated women. The largest differences between methods (P < 0.001) occurred in patients receiving oral conjugated estrogen (CE), while the best concordance was found in unmedicated women; like these controls, patients receiving oral estriol or transdermal E2 showed no significant difference between methods. Defining an E2 ratio > or = 2.0 as an abnormal discordance, the mean E2 ratio and the frequency of abnormal discordance in the CE group were 2.15 +/- 1.18 and 43.6%, respectively. No abnormal discordance for E2 occurred in other groups. In serial serum samples from the control group, no significant difference was seen between the mean E2 ratio at first measurement and those at a subsequent measurement. Similarly, no significant difference in the ratio was seen when two serial samples from CE patients were compared. However, E2 ratios after prescription of CE were significantly higher than before treatment in all patients. In conclusion, although measurement of E2 is important in patients receiving HRT, validity of the test methods must be carefully weighed for patients receiving CE.

Adolescent↗
PubMed1999

Reactive site-modified tissue inhibitor of metalloproteinases-2 inhibits the cell-mediated activation of progelatinase A.

Tissue inhibitor of metalloproteinases-2 (TIMP-2) is supposed to play a regulatory role in the cell-mediated activation of progelatinase A. To investigate the mechanism of the regulation, we prepared and characterized a chemically modified TIMP-2, and examined its effects on the activation of progelatinase A. We found that treatment of TIMP-2 with cyanate ion led to loss of inhibitory activity toward matrilysin or gelatinase A. Structural and functional analyses of the modified TIMP-2 showed that carbamylation of the alpha-amino group of the NH2-terminal Cys1 of TIMP-2 led to complete loss of the inhibitory activity. When the reactive-site modified TIMP-2 was added to culture medium of concanavalin A-stimulated HT1080 cells, the conversion of endogenous progelatinase A to the intermediate form was partially inhibited, whereas that of the intermediate form to the mature one was strongly inhibited. The reactive site-modified TIMP-2 also prevented an accumulation of active gelatinase A on the cell surface. We speculate that occupation of the hemopexin-like domain of gelatinase A by the reactive site-modified TIMP-2 makes it unable for gelatinase A to be retained on the cell surface, thus preventing the autocatalytic conversion of the intermediate form of gelatinase A to its mature form.

Amino Acid Sequence↗
PubMed1999

Inhibition of focus formation of transformed cloned cells by contact with non-transformed BALB/c 3T3 A31-1-1 cells.

When transformed cells were co-cultured with various densities of non-transformed BALB/c 3T3 A31-1-1 cells, the number of transformed cell foci decreased as the density of the A31-1-1 cells was increased. Under the condition of separate co-cultivation in which transformed cloned cells could not make contact with A31-1-1 cells, no inhibitory effect was induced. We examined with a dye-transfer assay the formation of heterologous gap-junctional intercellular communication (GJIC), links between the transformed cells and A31-1-1 cells before and after focus formation. Heterologous GJIC was observed almost always before, but almost never after, focus formation. Using time-lapse photography to record the fate of transformed cloned cells that did not form foci in the co-cultivation, it was noted that most of them were living, but did not proliferate. These results suggested that focus formation of transformed cloned cells was inhibited by contact with non-transformed A31-1-1 cells.

3T3 Cells↗