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Biomedical subjects

K Shinkai

Publications and source records attributed to K Shinkai.

At least 55 records · Page 3Linked to original sources
PubMed1995

Influence on HMG-COA reductase inhibitors on plaque-forming cell (PFC) response in mice.

Effects of pravastatin and simvastatin on the humoral immune response were studied using Cunningham's method of the IgM plaque-forming cell (PFC) assay system in mice. The vehicle (0.5% CMC), pravastatin (1 mg/body : about 50 mg/kg) or simvastatin (0.5 mg/body : about 25 mg/kg) were given orally for 14 days in experiment Exp-I and Exp-II. The vehicle, pravastatin (0.5 mg/body : about 25 mg/kg) or simvastatin (0.25 mg/body : about 12.5 mg/kg) were given orally 29 times for 32 days in Exp-III. There were no significant differences in the mean numbers of PFCs per 10(6) splenocytes between the pravastatin groups and the vehicle groups. In the simvastatin groups, however, there were significant reductions of the numbers of PFCs in Exp-I, Exp-II and Exp-III, as compared with the vehicle group. Based on these results, it was considered that suppressive effect on IgM antibody production was induced by simvastatin, whereas such a suppression was not observed with pravastatin.

Animals↗
PubMed1995

Wear resistance of resin cements.

PURPOSE: To evaluate the in vitro wear resistance of four resin cements and a glass ionomer cement using a three-body wear test. MATERIALS AND METHODS: Each cement was evaluated as a direct restorative material as well as in conjunction with an inlay. All restorations were placed into cylindrical shaped cavity preparations generated on the flattened occlusal surface of human extracted molars. The bulk wear resistance of a cement was determined when tested as a direct restorative material. RESULTS: The wear resistance of all cements was greater when tested in conjunction with a resin composite inlay restoration. Although wear of a cement is dependent upon the method of testing, it was greater when combined with a less wear resistant resin composite inlay material. All of the cement materials used in this study exhibited less wear resistance than the resin composite inlays with which they were used. This in vitro wear testing system can be used as a screening test for the cement materials before a clinical study.

Analysis of Variance↗
PubMed1995

Effect of gap dimension on wear resistance of luting agents.

PURPOSE: To examine the correlation between horizontal gap width and wear depth of luting resin cements and a glass ionomer used with resin composite inlays. MATERIALS AND METHODS: A cylindrical cavity (4 x 3 mm) was made on the occlusal surface of molars. Four specimens were prepared for each luting agent. The samples were subjected to a three-body wear test for 400,000 cycles. The wear values of both composite and luting agents were determined by profilometric tracings to the nearest 2 micrometers. The relationship between gap width and wear depth was confirmed by linear regression analysis. RESULTS: Significant relationships existed amongst gap width, cement wear and type of cement. The effects were considerably less pronounced with microfilled cements.

Analysis of Variance↗
PubMed1994

Effect of surface-penetrating sealant on wear resistance of luting agents.

The wear of composite resin is influenced by the presence of microcracks on its surface. Recently, it has been shown that surface-penetrating sealants are effective in reducing the wear of posterior composite resin by sealing these defects. The purpose of this study was to investigate the effects of one of these sealants on the wear of various luting agents in conjunction with composite resin inlays. The specimens were subjected to a three-body wear test for 400,000 cycles. The wear values of both composite resin and luting agents were determined by profilometric tracings to the nearest 2 microns. There were no statistically significant differences between the treated and untreated groups as it related to the wear of the luting agents. The wear values of composite resin inlays treated with the sealant, however, were significantly lower than those without treatment, regardless of the type of luting agent used for cementation.

Analysis of Variance↗
PubMed1993

cis-9,cis-15-octadecadienoic acid: a novel fatty acid found in higher plants.

An unusual fatty acid, cis-9,cis-15-octadecadienoic acid, has been identified in the pulp lipids of mango (Mangifera indica L.) grown in the Philippines. To our knowledge, the occurrence of cis-9,cis-15-octadecadienoic acid in higher plant lipids has not been previously reported. The structure confirmation was based on the results of chromatographic (capillary GC, argentation thin-layer) and spectrometric (GC-MS, infrared, ultraviolet) analysis and chemical treatment. This butylene-interrupted dienoic fatty acid is concentrated in the pulp part of mango fruit and occupies 5.4% of total acyl groups in the pulp lipids; whereas a common octadecadienoic acid, linoleic acid, is a minor component (1.1%) in the same lipids. If a trivial name is desired, it is suggested that cis-9,cis-15-octadecadienoic acid be called "mangiferic" acid.

Chromatography, Gas↗
PubMed1993

Induction of in vitro tumor cell invasion of cellular monolayers by lysophosphatidic acid or phospholipase D.

Serum is known to be required for invasion or phagokinesis of certain tumor cells, although the mechanism of its action is not well understood yet. In the in vitro invasion assay system we have developed, MM1 cells exhibiting extensive invasiveness against cultured mesothelial cell monolayers in the presence of 10% fetal calf serum did not invade them without serum. Human small cell lung cancer (OC10) cells also required serum in invasion. Serum could be completely substituted by oleoyl-lysophosphatidic acid (LPA) or bacterial phospholipase D (PLD). Phosphatidic acid also had an invasion-inducing activity, though to a lesser degree. Since human ovarian cancer (RMUG-S) cells require neither serum, LPA nor the PLD for invasion of mesothelial cell monolayers, the production of phospholipid like LPA, a candidate for intracellular second messenger, in tumor cells seems critical for the invasion by MM1 cells or OC10 cells. This result suggests a possible participation of particular signaling cascade, PLD-LPA(PA) system, in the invasion of certain tumor cells.

Animals↗
PubMed1993

Retraction of cultured endothelial cell monolayer by human breast cancer cells, MCF-7.

A human breast cancer cell line (MCF-7), when sealed on confluent bovine pulmonary aortic endothelial cell (CPAE) monolayers, induced morphological changes (retraction) in CPAE cells. The area of retraction depended on the incubation time and the number of MCF-7 cells, suggesting that MCF-7 cells had the capacity to retract CPAE cells. This capacity was reduced by 60% by pretreatment of MCF-7 cells with 17 beta-estradiol (E) and progesterone (Pg). The extent of retraction was not affected by the addition of various protease inhibitors. CPAE retraction was induced also by adding conditioned medium (CM) from the culture of MCF-7 cells. Considerably less activity was detected in the CM obtained from MCF-7 cells cultured in the presence of E and Pg. The retraction was reversed in 24 h by culturing the monolayer in fresh medium without CM and was not induced by trypsin treatment of the CM.

Breast Neoplasms↗
PubMed1993

Evidence for cis-trans isomerization of a double bond in the fatty acids of the psychrophilic bacterium Vibrio sp. strain ABE-1.

Vibrio sp. strain ABE-1 was grown in a medium that contained as its stable isotope tracer either [2,2-2H2]cis-9-hexadecenoic or [2,2-2H2]trans-9-hexadecenoic acid. Gas chromatographic-mass spectrometric analysis of the cis-9-hexadecenoic and trans-9-hexadecenoic acid fractions from the cells revealed the formation of an intracellularly isomerized 2,2-2H2-fatty acid which differed from the tracer only in the geometrical configuration of the double bond. This observation shows that cis-trans isomerization without a shift in double-bond position between these two geometric hexadecenoic acid isomers can occur in the cells.

Fatty Acids, Unsaturated↗
PubMed1993

Adaptation of composite fillings to cavity walls in three different cavities.

Adaptation of eight kinds of resin restorations on Class V enamel cavity, cement-enamel-junction (CEJ) cavity and root surface cavity were compared. Extracted human premolars were used as experimental specimens. Restored specimens were divided into two groups; short storage group of 2 week duration and long storage group of 6 month duration. The specimens were thermal cycled during storage. After that replicas of the vertical sections were made for examination by SEM and the gaps measured from photographs. The appearance and width of gaps between resin and cavity walls were characterised by the type of cavity and the filling materials. In Class V enamel cavity, gaps were observed on the cavity floor, whilst almost none was observed in other areas showing good adaptation. In the CEJ cavity, gaps appeared only at the cavity floor and gingival wall. In the root surface cavity, gaps were observed on all cavity walls with smaller widths on the occlusal wall and greater width on the cavity floor. Clearfil-F and Clearfil-F II showed fine adaptation on all cavities in general, especially on the dentinal cavity wall. Almost all the materials showed a tendency to form gaps which was found to increase with time. The difference in width, however, varied with the materials used.

Composite Resins↗
PubMed1993

[Mechanism of tumor cell invasion studied by a culture model--modification of invasiveness by host mediators].

A culture model for invasion of rat mesothelial cell layer by rat ascites hepatoma cells has been developed. By using this quantitative model, we have recently found that the invasiveness of tumor cells is not only genetically determined but is greatly influenced by their interactions with host cells and host mediators. The preculture with macrophages was found to enhance both the in vitro and in vivo invasive potentials of the tumor cells. This potentiation appears to be mediated partly by oxygen radicals generated by the cocultured macrophages. The in vitro invasive capacity was also augmented by pretreating the tumor cells with TGF-beta, or with activated platelets. In the in vitro invasion assay system, tumor cells did not invade against cultured mesothelial cell monolayers without fetal calf serum. Serum could be completely substituted by oleoyl-lysophosphatidic acid (LPA) or bacterial phospholipase D (PLD), suggesting a possible participation of particular signaling cascade, PLD-LPA(PA) system, in the invasion of certain tumor cells.

Animals↗
PubMed1993

[Difference of immunogenicity evoking in rabbits after immunization with a low-molecular antigen by various routes].

The present studies were undertaken to clarify the difference of the immunogenicity evoked in rabbits immunized with a low-molecular chemical antigen (TNBS) alone, by four administration routes. Rabbits were divided into four experimental groups: TNBS sc group, i.v. group, im group and ip group (3 times/week, 10 times in total), and immune responses to TNBS were estimated by the assay systems of humoral immunoreactions (HA.PCA.Arthus) and cellular immunoreaction (DTH). The highest evoking of the immunogenicity to TNBS was noted in the sc group in the case of humoral immune response, whereas the lowest evoking in the i.v. group. The intermediate degree of the immunogenicity was elicited in the im and ip groups. On the other hand, only the sc group displayed positive cellular immune response (DTH), while such immune response was never recognized in the i.v., im and ip groups. These results were indicated that the immunogenicity to the low-molecular antigen (TNBS) was evoked exceedingly in rabbits by sc sensitization route from view of humoral and cellular immune responses.

Animals↗
PubMed1992

Putrescine-dependent invasive capacity of rat ascites hepatoma cells.

The effects of inhibitors of polyamine synthesis on the invasive capacity of rat ascites hepatoma (LC-AH) cells were examined by in vitro assay of penetration of the LC-AH cells through a monolayer of calf pulmonary arterial endothelial (CPAE) cells. Pretreatment of LC-AH cells with alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, before seeding them onto a CPAE cell monolayer and culturing them for 24 h in the absence of DFMO decreased the number of penetrating tumor cells time and dose dependently (about 35% of the maximal inhibition) without affecting their viability or proliferative activity. DFMO treatment caused a marked decrease in the intracellular level of putrescine but not of spermidine or spermine. The DFMO-induced decreases in invasive capacity and putrescine level were almost completely reversed by the addition of putrescine to the medium during pretreatment with DFMO or invasion assay but were not affected by exogenous spermidine or spermine. No change in the invasive capacity was observed when the CPAE cells were treated with DFMO and the LC-AH cells with methylglyoxal-bis(guanylhydrazone), an inhibitor of S-adenosylmethionine decarboxylase, which depressed the spermidine and spermine levels but increased the putrescine level in the LC-AH cells. These results suggest that intracellular putrescine modulates the in vitro invasive capacity of LC-AH cells.

Animals↗
PubMed1992

Tumor invasion-inhibiting factor 2: primary structure and inhibitory effect on invasion in vitro and pulmonary metastasis of tumor cells.

The primary structure of tumor invasion-inhibiting factor 2 (IIF-2) purified from bovine liver (A. Isoai et al., Jpn. J. Cancer Res., 81:909-914, 1990) was determined. A computer homology search of the National Biomedical Research Foundation data bank revealed that IIF-2 is identical to the carboxyl-terminal region, residue number [69-89], of high mobility group 17 which is a DNA-binding non-histone protein. IIF-2 synthesized by an automated peptide synthesizer showed similar invasion-inhibitory activity as compared with the purified factor, when tested with the monolayer invasion assay system using highly invasive rat ascites tumor cells. When examined with the other in vitro assay systems using a modified Boyden chamber, the synthetic IIF-2 suppressed the chemotactic migration of highly metastatic B16 melanoma (B16FE7) cells to fibronectin or laminin and invasion through Matrigel. The IIF-2 inhibited neither the cell proliferation nor the binding of cells to fibronectin or Matrigel and also showed no significant inhibition of Mr 90,000 type IV collagenase (gelatinase) obtained from human schwannoma (YST-3) cells. The formation of lung colonies in mice given injections of B16FE7 and Lewis lung carcinoma cells was significantly reduced by the coinjection of the IIF-2. These results suggest that IIF-2 suppresses tumor invasion by impairing cell motility and inhibits the migration of metastasizing cells through extracellular matrix (extravasation steps) following their arrest in the capillary bed of the lung in vivo.

Amino Acid Sequence↗
PubMed1992

Alternating non-cross-resistant chemotherapy for non-Hodgkin's lymphoma of intermediate-grade and high-grade malignancy. A pilot study.

Thirty-two patients with advanced non-Hodgkin's lymphoma (NHL) with aggressive histologic findings were treated with cyclophosphamide, doxorubicin, methotrexate with leucovorin rescue, bleomycin, vincristine, etoposide, ifosfamide, and prednisolone (CAMBO-VIP), in which presumably non-cross-resistant myelosuppressive and nonmyelosuppressive agents were administered during alternate weeks for 12 weeks. To ensure the high-dose intensity of the protocol, dose reduction and delay in treatment were minimized. Three patients were treated inadequately. Twenty-six (89.7%) of 29 evaluable patients had a complete response, and three had a good partial response. Relapse occurred in four patients, with a median follow-up of 29 months. The actuarial overall survival and disease-free survival were estimated to be 87.6% and 75.9%, respectively. The CAMBO-VIP treatment was well tolerated; myelosuppression was severe but transient and caused no serious infections. Side effects that affected dose intensity were oral ulceration, occurring in 28 patients, and blister formation under the thickened skin of palms and/or soles, followed by desquamation (5 patients). Hepatic toxicity was generally mild to moderate; it was severe in one patient. A 12-week regimen of CAMBO-VIP was effective for advanced NHL with aggressive histologic findings.

Adolescent↗
PubMed1992

Interactions of lung cancer cells with the human mesothelial cell monolayer: an in vitro model for cancer invasion.

An in vitro monolayer model for cancer invasion was developed, comprising cultured layers of human pleura-derived mesothelial cells (PM cells). The cells were isolated from normal human pleura at autopsy and cultured in RPMI-1640 supplemented with 10% fetal calf serum; they were polygonal in shape, forming a pavement-like structure, and preserved the morphologic characteristics of mesothelial cells. When small cell lung cancer cells (OC-10 cells) were seeded on to the monolayer of PM cells, they attached themselves to the monolayer, invaded it and formed flattened cancer cell nests beneath it. By counting the number of cancer cells penetrated, the in vitro invasiveness (invasive capacity) of the cancer cells was assayed. The invasive capacity of poorly invasive cells (10N), which were cloned from OC-10 cells, was five times less than that of the parental OC-10 cells. These results indicate our system to provide a useful model for studying human cancer cell invasion.

Carcinoma, Small Cell↗
PubMed1992

[Immunophenotyping analysis of acute undifferentiated leukemia].

The diagnosis of acute undifferentiated leukemia (AUL) is made when the leukemic cells do not have cytologic or cytochemical features of myeloid cells, and do not express myeloid antigens (CD13, CD14, CD33, CD41 etc.) or lymphoid antigens (CD2, CD3, CD19, CD20, Sm Ig etc.). Most of these cells are reported to be positive for CD7, CD34, TdT and HLA-DR, either alone or in combination. Cell lineage can be suspected in most AUL cells by genotypic analysis, phenotypic analysis after culturing with TPA, or peroxidase activity by ultrastructural or immunohistochemical analysis, which indicates the heterogeneity of AUL. The patients with AUL appear to have a poor prognosis with conventional chemotherapy.

Acute Disease↗
PubMed1992

[Rearrangement of immunoglobulin light chain and heavy chain constant region genes in multiple myeloma].

We analysed immunoglobulin (Ig) gene rearrangements in 28 patients with multiple myeloma by Southern hybridization method. We used 5 probes which cover C kappa and kappa de loci of Ig light chain kappa gene, and JH, 5'S mu and S gamma 3 loci of Ig heavy chain gene. In 11 out of 12 patients with kappa-producing myeloma, DNA rearrangements were observed using C kappa probe. Among them, kappa de region was rearranged in 7 patients and kept germline configuration in 4 patients. In all of 14 patients with lambda-producing myeloma, C kappa region was deleted and kappa de region was rearranged. 5'S mu-probe was very useful for detecting class switch recombination, and furthermore by using S gamma-probe together, S mu-S gamma joining could be detected. In all of 10 patients with gamma-producing myeloma, 5'S mu and S gamma-probes detected the rearranged band of the same size on at least 1 allele, which suggested the presence of S mu-S gamma joinings. In 8 of 10 patients with Bence-Jones myeloma, 5'S mu-probe detected rearranged bands and the presence of class switch recombinations were suggested as observed in other Ig secretory myelomas. In other 2 patients with Bence-Jones myeloma, non-functional class switch recombinations were detected. The results of this study indicated that genotypes corresponded well to phenotypes in multiple myeloma, and further analysis in other types of B cell malignancies will be interesting.

Gene Rearrangement, B-Lymphocyte, Heavy Chain↗