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S Yamagata

Publications and source records attributed to S Yamagata.

At least 73 records · Page 4Linked to original sources
PubMed1997

Biochemical characterization of glycyrrhizin as an effective inhibitor for hyaluronidases from bovine testis.

The inhibitory effects of several anti-inflammatory agents, including glycyrrhizin (GL), on the activities of hyaluronidases (HAses) purified from bovine testes and Streptomyces were investigated in vitro. It was found that (i) GL inhibits the activity of HAse (p55) from bovine testes in a dose-dependent manner, but does not affect HAse from Streptomyces; (ii) GL was the most effective of the compounds tested on bovine testis HAse activity (50% inhibition with approx. 3 microM GL); and (iii) glycyrrhetinic acid (GA), a derivative (oGA) of GA and diglucuronic acid had no detectable effects on HAse activity at 9.0 microM. The GL-induced inhibition of HAse activity is uncompetitive for its substrates. Data are provided to support the contentions that (i) bovine testis HAse (p55) is a GL-binding protein; and (ii) GL acts as a potent inhibitor of HAse in vitro.

Animals↗
PubMed1996

Novel selective PDE IV inhibitors as antiasthmatic agents. Synthesis and biological activities of a series of 1-aryl-2,3-bis(hydroxymethyl)naphthalene lignans.

A series of 1-aryl-2,3-bis(hydroxymethyl)naphthalene lignans have been synthesized and evaluated for their ability to selectively inhibit PDE IV isolated from guinea pig. Replacement of the 1-phenyl ring by a pyridone ring led to marked improvement of their selectivity for PDE IV over PDE III. The compounds that were most potent and selective involved those bearing an N-alkylpyridone ring at C-1. These compounds also showed potent antispasmogenic activity without causing significant changes in heart rate in the guinea pig. The most potent compound was 6,7-diethoxy-2, 3-bis(hydroxymethyl)-1-[1-(2-methoxyethyl)-2-oxo-pyrid-4-yl]nap hth alene (17f), ED50 values of histamine-induced and antigen-induced bronchoconstriction in the guinea pig being 0.08 and 2.3 mg/kg iv, respectively. This compound was chosen as a candidate for further pharmacological evaluation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1996

Establishment and characterization of high- and low-lung-metastatic cell lines derived from murine colon adenocarcinoma 26 tumor line.

We established and characterized high- (LuM1) and low-lung-metastatic (NM11) cell lines derived from murine colon adenocarcinoma 26 tumor line. LuM1 cell line was established as a clonal cell line from a cultured cell mixture derived from a lung-metastatic nodule after 7 sequential subcutaneous transplantations of lung-metastatic tumors in the abdominal wall of BALB/c mice. NM11 cell line was established from a cultured cell mixture derived from a subcutaneous transplant of murine colon adenocarcinoma 26 tumor cells. LuM1 cells showed marked spontaneous lung metastases, but NM11 cells rarely did. High invasive potential of LuM1 cells was revealed by in vitro invasion assay using Matrigel reconstituted membranes. Rapid retraction was observed in monolayers of human umbilical vein endothelial cells and bovine aortic endothelial cells when LuM1 cells were added on the monolayers. Gelatin zymography and immunochemical examinations with monoclonal antibodies against gelatinase B (Mr 95,000 type IV collagenase) showed secretion of large amounts of the gelatinase by LuM1 cells.

Adenocarcinoma↗
PubMed1996

The use of epoxy patch grafts for the repair of experimentally-created diaphragmatic defects in dogs.

Canine pericardium which had been treated with polyepoxy compounds (Denacol EX-313) was used as a patch graft for the correction of experimentally-created diaphragmatic defects in five dogs belonging to the same litter. Clinical, macroscopic and histological examinations were conducted every month up to five months after suturing of the patch graft. Clinical examination of the patch graft showed no apparent abnormalities. Macroscopic examination conducted during autopsy showed that the patch graft maintained adequate elasticity for five months after suturing, the surface of the patch graft was covered with a thin membrane and neovascularization was observed. Histological examination showed that the surface of the patch graft was covered with a thin membrane. Inflammatory tissue reactions were observed at one month, but gradually decreased from the second month onwards. In addition, the patch graft had excellent tissue affinity.

Animals↗
PubMed1995

Characterization of extracellular matrix-degrading proteinase and its inhibitor in gynecologic cancer tissues with clinically different metastatic form.

BACKGROUND: The authors conducted a comparison study of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase-1 (TIMP-1) activities in clinically different metastatic types of ovarian cancer, cervical cancer, and endometrial cancer tissues. METHODS: Gelatinase activity in culture medium obtained from each cancer tissue was detected by zymography and was quantitated by densitometer. Tissue inhibitor of metalloproteinase-1 activity was measured in culture medium by the human TIMP-1 enzyme immunoassay kit. RESULTS: Six dominant gelatinases were detected in ovarian, cervical, and endometrial cancers: 200-kDa; 130-kDa; 92-kDa (MMP-9); 83-kDa, which is an active form of 92-kDa gelatinase; 72-kDa (MMP-2); and 66-kDa gelatinase, which is an active form of 72-kDa gelatinase. The 92-kDa and 72-kDa gelatinolytic bands were present in all samples. The expression rates of 200-, 130-, and 83-kDa gelatinase in endometrial cancer and cervical cancer tissues were higher than that observed in ovarian cancer tissue. Densitometric analysis showed that the 92-kDa/72-kDa ratio was significantly higher in cervical cancer tissue than in ovarian and endometrial cancer tissues (P < 0.05), and the 66-kDa/72-kDa ratio was significantly higher in endometrial cancer tissue than in ovarian cancer tissue (P < 0.01). Tissue inhibitor of metalloproteinase-1 activity was significantly lower in cervical cancer tissue than in ovarian and endometrial cancer tissues (P < 0.01). CONCLUSIONS: These results reflect the difference of metastatic forms and are indicative of the possibility of the strong relationship to MMP activity in the invasion and metastasis of cervical cancer and endometrial cancer, compared with those of ovarian cancer.

Collagenases↗
PubMed1995

Augmentation of metalloproteinase (gelatinase) activity secreted from Rous sarcoma virus-infected cells correlates with transforming activity of src.

To search for the biochemical properties of cells relevant to transformation by p60v-src, we examined the activities and amounts of metalloproteinase (gelatinase) released from chicken embryonic fibroblasts infected with various mutants of Rous sarcoma virus by zymography and immunoblotting. While nontransforming Src proteins, including cellular p60c-src and its nonmyristylated form, had no stimulatory effect, wild-type p60v-src and the transforming mutant of cellular p60c-src stimulated the secretion and proteolytic activation of metalloproteinases. Moreover, the activation of metalloproteinase secretion strongly correlated with the invasiveness of cells assayed by the modified Boyden Chamber method. Chimeric mutants between v-src and c-src, which are transforming but produce less distinct morphological changes in infected cells, also stimulated the secretion of metalloproteinases as well as wild-type p60v-src. Deletion mutants of v-Src in which varying portions of the NH2-terminal half of p60v-src are deleted stimulated secretion to a level similar to that of wild-type regardless of the degree of morphological change they induce. Together with Src protein, other oncogene products including Yes, Fps, ErbB and Crk were also found to stimulate the secretion of metalloproteinases. Thus, these results suggest that transformation of cells with src and other oncogenes is closely associated with the enhanced secretion of metalloproteinases that may play an important role in tumor invasion and metastasis.

Animals↗
PubMed1995

Analysis of glycosaminoglycan-degrading enzymes by substrate gel electrophoresis (zymography).

Substrate gel electrophoresis is of use for detecting minute amounts of hyaluronidase (HAase). In substrate gel electrophoresis, hyaluronan (HA) is impregnated in a gel. To determine the presence of degradation enzymes for other glycosaminoglycans (GAGs), the sizes of whose molecules are much smaller than that of HA, we have developed a technique by which chondroitin sulfate (CS) is chemically modified by introducing an allyl group at the reducing end for its immobilization in the gel. Enzymes with CS-degrading activity were detected on a CS-copolymerized gel in the presence or absence of sodium dodecyl sulfate. The smallest amount of chondroitinase ABC and HAase was found to be 8 microU and 0.35 mU, respectively. By zymography using HA-impregnated and modified CS-copolymerized gels human serum HAase has been shown to consist of at least two isoforms each with its own substrate specificity. Using this method, uterine tumor tissue has been shown to secrete a novel HAase which degrades HA at neutral pH, but not CS at any pH. This method was also confirmed applicable to other GAGs for determining individual GAG-degrading enzymes. In future research, it will be used to examine the regulation of each GAG species in tissue.

Acrylamide↗
PubMed1995

Polypoid growth and K-ras codon 12 mutation in colorectal cancer.

BACKGROUND: To clarify genetic changes in colorectal tumorigenesis, K-ras codon 12 point mutations were examined in 101 ordinary colorectal carcinomas and 6 that complicated ulcerative colitis (UC) with special attention to growth patterns. METHODS: The depths of invasion of ordinary carcinoma were submucosa (SMCa) in 39 cases, muscularis propria (PMCa) in 33, and far-advanced in 29. Growth patterns of SMCa and PMCa were classified into three types: polypoid-growth type without central depression (Type 1), polypoid-growth type with central depression (Type 2), and nonpolypoid-growth type. DNA samples were extracted from formalin fixed paraffin embedded sections, and K-ras codon 12 mutations were examined by two-step polymerase chain reaction-restriction fragment length polymorphism. RESULTS: K-ras mutation frequency was higher in Type 1 SMCa than in nonpolypoid SMCa, 56% (9/16) versus 6% (1/17), respectively, and in PMCa, 78% (7/9) versus 23% (3/13), respectively. In 6 UC carcinomas, a K-ras mutation was detected in only one polypoid carcinoma and none were detected in five nonpolypoid carcinomas. CONCLUSIONS: These results and the authors' previous study suggest that nonpolypoid carcinomas may be derived from flat adenomas, whose K-ras mutation incidence also was low, and this pathway is different from a genetic model based on the ordinary adenoma-carcinoma sequence through polypoid adenomas.

Adenoma↗
PubMed1995

[An epidemiological study of stroke in a geriatric community--with special reference meteorological factors].

The incidence of cerebrovascular event during a period of 3 years in the geriatric society in Japan was examined along with the alternating pattern of cerebrovascular accidents in relation to aging and seasonal factors. The population of Tsuwano town was approximately 7000. The percentage of aged people over 65-year-old reached 23.1% in the 1990 national census. All cerebrovascular accident patients in our hospital and two outpatients clinic in this city were registered during the period from April, 1990 to March, 1993. The number of patients in the period was 95 cases, of which 19 were classified as transient ischemic attack (TIA), 30 as cerebral thrombosis, 16 as cerebral embolism, 10 as cerebral hemorrhage, 7 as subarachnoid hemorrhage, and 13 as unclassified cerebral infarction. The frequency of each type except TIA was 39.5% cerebral thrombosis, 21.1% cerebral embolism, 13.2% cerebral hemorrhage, and 9.2% subarachnoid hemorrhage. In all cases, hypertension was observed in 62.1%, and past history of cerebrovascular accident was observed in 29.5%. The cerebral embolism group was older than the other groups and one-half of this group had atrial fibrillation. Peak incidence differed by type of illness, TIA and cerebral embolism occurred uniformly throughout the year, but subarachnoid hemorrhage and cerebral thrombosis in the spring. The relationship of cerebrovascular accident to crisis, especially potentiation by cerebral thrombosis was evaluated in light of climatic factors.

Aged↗
PubMed1995

[Precancerous lesion in colorectal cancer].

Precancerous lesion in colorectal cancer was reviewed in terms of the evolution of the adenomacarcinoma sequence. K-ras codon 12 point mutation frequencies, examined in 157 adenomas, were observed in polypoid adenomas (67%) and flat adenomas (21%). Among flat adenomas, completely flat or depressed ones showed especially low mutation frequency (8%). K-ras mutation frequencies, examined in 70 invasive carcinomas, were observed in polypoid carcinomas (64%) and nonpolypoid ones (13%). From the results, it is suggested that polypoid adenomas develop into polypoid carcinomas and flat adenomas into non-polypoid carcinomas.

Adenoma↗
PubMed1994

Autocrine factor enhancing the secretion of M(r) 95,000 gelatinase (matrix metalloproteinase 9) in serum-free medium conditioned with murine metastatic colon carcinoma cells.

We previously reported that murine tumor cells with a high spontaneous metastatic potential to the lung secrete higher amounts of M(r) 95,000 gelatinase (matrix metalloproteinase 9, MMP9) than do poorly metastatic cells. The present study, conducted to clarify the mechanisms underlying the increase in MMP9, revealed an autocrine factor that enhances the secretion of M(r) 95,000 gelatinase (MMP9). The secretion of MMP9 by highly metastatic colon carcinoma LuM1 cells, detected by zymography, was augmented 10-fold when cultured in medium supplemented with serum-free medium conditioned with LuM1 cells. Because the secretion of M(r) 60,000 gelatinase (MMP2), as well as total protein, by the same cells was not affected under these conditions, the augmentation appears specific for MMP9. The steady-state level of MMP9 mRNA was elevated in LuM1 cells cultured in the presence of the supernatant. The amount of the factor in the culture medium increased with time in culture, indicating that it was produced by the LuM1 cells. It was found to be heat stable but sensitive to trypsin digestion. Conditioned medium from poorly metastatic NM11 cells did not stimulate the secretion of gelatinases by NM11 cells, suggesting that autocrine stimulation of MMP9 secretion is a characteristic of metastatic cells. This factor could account for the augmented secretion of MMP9 by murine tumor cells with spontaneous metastatic potential to the lung.

Animals↗
PubMed1994

Ischemia-induced changes in catecholamine release and their mechanisms: a study using cultured bovine adrenal chromaffin cells.

Ischemia-induced changes in neurotransmitter release and their mechanisms were examined using cultured bovine adrenal chromaffin cells. When the cells were incubated in glucose-free media equilibrated with 0% O2/100% N2 (ischemia), ATP content decreased and reached the minimum level within 40 min. Control incubation was done in media equilibrated with 21% O2 in N2. After 10-min incubation under ischemic conditions, basal catecholamine (CA) release was elevated and the elevation persisted up to 90 min. High K(+)-evoked CA release was transiently enhanced at 10 min, but after that, it decreased to reach the minimum level at 60 min. At 10 min, cytosolic free Ca2+ concentration ([Ca2+]i) and 45Ca2+ uptake of the resting cells (basal values) and high K(+)-evoked increases in these two parameters were unchanged, but CA release from permeabilized cells in response to Ca2+ in media was augmented. After 60-min incubation under ischemic conditions, basal [Ca2+]i was elevated: the elevation was observed even in the absence of extracellular Ca2+. In contrast, high K(+)-evoked increases in [Ca2+]i and in 45Ca2+ uptake were suppressed, but basal 45Ca2+ uptake into intact cells and CA release from permeabilized cells were unchanged. These results suggest that in an early phase (10 min) of ischemia, both basal and stimulation-evoked CA release are augmented because of increased sensitivity of exocytotic machinery to Ca2+. In the late phase (60 min), basal CA release is augmented because of an increase in basal [Ca2+]i, which is due to accumulation of Ca2+ derived from intracellular Ca2+ pools: stimulation-evoked CA release is suppressed because of inhibition of stimulation-evoked increase in [Ca2+]i, which is due to functional disturbance of voltage-dependent Ca2+ channels.

Adenosine Triphosphate↗
PubMed1994

Gelatinases and metalloproteinase inhibitor secreted by murine colonic carcinoma cells with differing metastatic potential.

Gelatinase activity and inhibitory activity against collagenase were measured in serum-free medium conditioned by murine colonic carcinoma cells with different spontaneous metastatic potentials to the lung. The medium conditioned with poorly metastatic NM11 cells gave higher inhibitory activity than that conditioned with highly metastatic LuM1 cells, while the level of secreted gelatinases in the same medium was lower in NM11 medium than in LuM1 case. Northern analysis showed the higher gene expression of both tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 in NM11 cells than in LuM1 cells, suggesting that both TIMPs are responsible for the increase of inhibitory activity in NM11 conditioned medium. Examination of the balance of gelatinases and inhibitor revealed that the amount of inhibitor exceeded that of gelatinases in the medium conditioned with NM11 cells. In contrast, the medium conditioned with LuM1 cells contained excess amounts of gelatinases. The results indicated a close correlation between the balance of gelatinases and inhibitors and the metastatic behavior of murine tumor cells.

Animals↗
PubMed1994

Overexpression of the Saccharomyces cerevisiae MET17/MET25 gene in Escherichia coli and comparative characterization of the product with O-acetylserine.O-acetylhomoserine sulfhydrylase of the yeast.

The Saccharomyces cerevisiae MET17/MET25 gene encoding O-acetyl-L-serine (OAS).O-acetyl-L-homoserine (OAH) sulfhydrylase (EC 4.2.99.10) was overexpressed in Escherichia coli and the gene product was purified to homogeneity, using three steps, with a recovery of 28% from the total cell extract. The gene product has been compared with OAS.OAH sulfhydrylase purified from the yeast cells. These two protein preparations were indistinguishable with respect to their behavior in polyacrylamide gel electrophoresis, both with and without sodium dodecyl sulfate, their specificity for substrate amino acids, Michaelis constant (Km) value for OAH, sensitivity to carbonyl reagents, absorption spectrum, isoelectric point, behavior in HPLC (both ion-exchange chromatography and gel filtration), sensitivity to heat treatment, susceptibility to trypsin digestion, and their N-terminal amino acid sequence. The results obtained imply that the gene product is properly processed in E. coli, and the technique developed in this study to overexpress the gene in bacterial cells provides us with a large amount of the purified preparation of the enzyme. In contrast to a previous report we found that cystathionine gamma-lyase of S.

Amino Acid Sequence↗
PubMed1994

Autofluorescence in onset of gastric mucosal injury induced by hemorrhagic shock in rats.

In an attempt to clarify whether gastric mucosal autofluorescence can help us to recognize gastric lesions at the onset of their formation, we investigated the fluorescence generated from the gastric mucosa of rats under ischemia-reperfusion stress. Red-colored fluorescence appeared and began to increase within 5 min after reperfusion. Such an increase in fluorescence did not occur in the gastric mucosa under prolonged ischemia without reperfusion. The epifluorescence microscopy of mucosal cryosections revealed that fluorescence was present even when only superficial mucosal damage occurred. Spectrofluorometric and high-performance liquid chromatographic analysis of the fluorescent mucosa extract identified the fluorescent substances as porphyrins. These findings suggested that fluorescent porphyrins are generated in the mucosal layer during the introductory phase of mucosal lesion formation induced by ischemia-reperfusion stress.

Animals↗
PubMed1994

Different pattern of zymography between human gynecologic normal and malignant tissues.

OBJECTIVE: Our purpose was to evaluate type IV collagenase in ovarian and endometrial cancer tissues. STUDY DESIGN: Tissue specimens were obtained from patients with ovarian and endometrial cancer and uterine myoma. Gelatinase activity was detected by zymography and quantitated by densitometer. RESULTS: Four dominant gelatinases were detected in ovarian and endometrial cancer tissues: 200, 130, 92, and 72 kd gelatinase. Other forms observed were 83 kd gelatinase, which is an active form of 92 kd gelatinase, and 66 kd gelatinase, which is an active form of 72 kd gelatinase. Densitometric analysis showed that the 92 kd/72 kd ratio in ovarian cancer tissues was significantly higher than in normal ovarian tissues (p < 0.05) and that the 66 kd/72 kd ratio was higher in ovarian cancer tissues (p = 0.07). Both ratios in endometrial cancer tissues were significantly higher than in normal endometrial tissues (p < 0.05). CONCLUSION: Gelatinase activity was remarkably higher in ovarian and endometrial cancer tissues. Especially, 92, 83, and 66 kd gelatinases were clearly detected in cancer tissues, suggesting that these gelatinases were related to the malignant phenotype, because degradation of the components of the basement membrane such as type IV collagen is necessary for cancer cells to metastasize.

Adult↗
PubMed1994

Lower incidence of K-ras codon 12 mutation in flat colorectal adenomas than in polypoid adenomas.

In order to clarify genetic changes in flat adenomas, K-ras codon 12 point mutations were examined in 56 flat adenomas, 81 polypoid adenomas and 42 cancers of colon and rectum. The mutation frequency in flat adenomas was 23% (13/56), significantly lower than that in polypoid adenomas (67%: 54/81) and cancers (76%: 32/42). Even mildly dysplastic adenomas or small (less than 5 mm) adenomas showed higher mutation incidence in polypoid type (62%, 57%) than in flat type (23%, 19%). Among flat adenomas, flat elevated lesions exhibited relatively higher mutation frequency than completely flat or depressed ones. As for cancers, 14 tumors (33%) contained mutations only in a minor tumor cell population, indicating that these mutations occur at a late stage of tumorigenesis. These results suggest that the adenoma-carcinoma sequence through flat adenomas may be different from that through polypoid adenomas, and genetic changes may be heterogeneous in colorectal carcinogenesis.

Adenoma↗