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Biomedical subjects

K Miyazaki

Publications and source records attributed to K Miyazaki.

At least 91 records · Page 5Linked to original sources
PubMed2001

Sole expression of laminin gamma 2 chain in invading tumor cells and its association with stromal fibrosis in lung adenocarcinomas.

Laminin-5 (LN-5), an important basement membrane (BM) protein consisting of laminin alpha3, beta3 and gamma 2 chains, has been suggested to be involved in tumor cell invasion and tissue repair. In this study, the distribution of the LN-5 subunits in atypical adenomatous hyperplasia (AAH) and different types of adenocarcinomas of the lung was examined by immunohistochemical analysis. In AAH and non-sclerosing, well-differentiated adenocarcinomas, the LN gamma 2 chain was frequently detected along with the continuous BMs. These BMs were also positive for both LN alpha3 and beta3 chains, suggesting that LN-5 had been deposited. In contrast, the cytoplasmic staining for the LN gamma 2 chain was frequently observed in tumor cells of sclerosing, well-differentiated adenocarcinomas, as well as of moderately and poorly differentiated adenocarcinomas, without any evidence of co-expression of the LN alpha3 and beta3 chains. This staining pattern of the LN gamma 2 chain was prominent in carcinoma cells invading into interstitial stroma and was associated with the formation of a central scar in the tumor tissues. These results suggest that the LN gamma 2 chain monomer could be an important indicator of progression of lung adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Nuclear entry mechanism of rat PER2 (rPER2): role of rPER2 in nuclear localization of CRY protein.

Mammalian PERIOD2 protein (PER2) is the product of a clock gene that controls circadian rhythms, because PER2-deficient mice have an arrhythmic phenotype. The nuclear entry regulation of clock gene products is a key step in proper circadian rhythm formation in both Drosophila and mammals, because the periodic transcription of clock genes is controlled by an intracellular, oscillating, negative feedback loop. The present study used deletion mutants of rat PER2 (rPER2) to identify the functional nuclear localization signal (NLS) in rPER2. The elimination of putative NLS (residues 778 to 794) from the rPER2 fragment resulted in the loss of nuclear entry activity. Adding the NLS to the cytosolic protein (bacterial alkaline phosphatase) translocates the fusion protein to the nuclei. The data indicate the presence of a functional NLS in rPER2. Furthermore, intact rPER2 was preferentially translocated from the cytoplasm to the nucleus when coexpressed with human CRY1 (hCRY1). However, rPER2 mutants lacking a carboxyl-terminal domain could not enter the nucleus even in the presence of hCRY1. In addition, coexpression of the nuclear localization domain (residues 512 to 794) lacking rPER2 and CRY1 changed the subcellular localization of CRY1 from the nucleus to the cytoplasm. In vitro protein interaction studies demonstrated that the carboxyl-terminal domain of rPER2 is essential for binding to CRY1. The data suggested that both the rPER2 NLS and carboxyl-terminal CRY binding domain are essential for nuclear entry of the rPER2-CRY1 complex.

Active Transport, Cell Nucleus↗
PubMed2001

Successful pregnancy in a woman with ovarian failure associated with mutation in the beta-subunit of luteinizing hormone.

BACKGROUND: We report a successful pregnancy in a woman with severe ovarian dysfunction and infertility associated with a variant beta-subunit of luteinizing hormone (LH). METHOD/OUTCOME: A 35-year-old woman consulted our unit for infertility. Laparoscopy and ultrasonography showed obstruction of the right tube and ovulation from the right ovary only. Human menopausal gonadotrophin (hMG) therapy was used for six subsequent cycles, but did not result in conception. Subsequently, marked elevation of follicle-stimulating hormone (FSH) and testosterone, together with polycystic ovary (PCO) were noted. The patient failed to respond to ovarian stimulation by hMG. Severe ovarian dysfunction such as premature ovarian failure (POF) was strongly suspected. Sequence analysis of the LH beta-subunit gene indicated heterozygosity for point mutations Trp(8) to Arg(8) and Ile(15) to Thr(15) in the coding sequence. LH hypersecretion resembling that seen in PCO syndrome was observed. Induction of ovulation by hMG was successful in the first cycle in which the basal LH and FSH were well controlled with gonadotrophin-releasing hormone analog following estrogen-progesterone replacement. She conceived and delivered a healthy male infant at term. CONCLUSION: Clinicians should be clinically aware of patients with immunologically anomalous LH variant who might be at risk of developing ovarian failure within a relatively short time span. Pertinent treatment should be applied without delay in such cases.

Adult↗
PubMed2001

Clinical value of thymidine kinase in patients with cervical carcinoma.

OBJECTIVE: Our purpose was to determine the clinical value of thymidine kinase (TK), which is an important pyrimidine pathway enzyme involved in salvage DNA synthesis, in patients with cervical carcinoma. METHODS: We examined TK mRNA expression by reverse transcription polymerase chain reaction in 19 tissue specimens of invasive cervical carcinoma and 9 normal cervices and related it to thymidylate synthase (TS) and thymidine phosphorylase (TP) mRNA expressions. Serum TK level was determined by radioenzymatic assay in 79 patients with invasive cervical carcinoma, 7 patients with microinvasive carcinoma, 21 patients with carcinoma in situ and 32 normal women. RESULTS: TK mRNA expression was upregulated in invasive cervical carcinoma compared with the normal cervix (p < 0.05) and significantly correlated with TS mRNA expression (p < 0.0001) but not with TP mRNA expression. The serum TK level was significantly higher in patients with invasive carcinoma than in normal women and patients with carcinoma in situ (p < 0.01 and p < 0.05). In patients with invasive cervical carcinoma, the serum TK level significantly correlated with TK mRNA expression (p < 0.05), but not with any conventional clinicopathologic factors. High serum TK levels significantly correlated with a poorer survival (p < 0.05), and multivariate analysis showed serum TK level to be an independent prognostic factor (p < 0.05). CONCLUSION: TK may play an important role in influencing the malignant behavior of cervical carcinoma, and measurement of the serum TK level may be useful in predicting survival in patients with cervical carcinoma.

Adult↗
PubMed2001

Preparation of and tissue response to DNA-lipid films.

DNA-containing films have the potential to form complexes with antibiotics or cytokines by intercalation or groove-binding. This principle can be highly relevant for regenerative wound-healing around oral implants and in periodontology. In this study, we prepared DNA-lipid films and examined tissue responses to them as an indicator of their biological properties. The lipids were synthesized from the reaction of L-alanine, n-alkyl alcohol, and p-toluenesulfonic acid. We prepared the self-standing, water-insoluble DNA-lipid films by casting the DNA-lipid complex from chloroform/ethanol solution. The DNA-lipid complexes, which had 1:1 ratios of phosphate anions to cationic lipid, were found to have a double-helical B-form structure. The DNA-lipid films were almost dissolved 3 days after subcutaneous implantation in the backs of rats. There were no inflammatory reactions or inhibition of new tissue formation. We concluded that DNA-lipid films can be prepared by simple methods, and that they do not cause an unfavorable tissue response.

Absorbable Implants↗
PubMed2001

Identification of cariostatic substances in the cacao bean husk: their anti-glucosyltransferase and antibacterial activities.

The cacao bean husk has been shown to possess two types of cariostatic substances, one showing anti-glucosyltransferase (GTF) activity and the other antibacterial activity, and to inhibit experimental dental caries in rats infected with mutans streptococci. In the present study, chromatographic purification revealed high-molecular-weight polyphenolic compounds and unsaturated fatty acids as active components. The former, which showed strong anti-GTF activity, were polymeric epicatechins with C-4beta and C-8 intermolecular bonds estimated to be 4636 in molecular weight in an acetylated form. The latter, which showed bactericidal activity against Streptococcus mutans, were determined to be oleic and linoleic acids, and demonstrated a high level of activity at a concentration of 30 microgram/mL. The cariostatic activity of the cacao bean husk is likely caused by these biologically active constituents.

Anti-Infective Agents, Local↗
PubMed2001

Involvement of mitogen-activated protein kinase in cyclic adenosine 3',5'-monophosphate-induced hormone gene expression in rat pituitary GH(3) cells.

We examined whether mitogen-activated protein (MAP) kinase was activated by stimulation of the cAMP pathway and whether MAP kinase activation was involved in synthesis of PRL and GH in GH(3) cells. Treatment of the cells with a cAMP analog, 8-(4-chlorophenylthio)cAMP (CPT-cAMP), activated MAP kinase and increased PRL at both the protein and messenger RNA levels. The protein and messenger RNA of GH were decreased by the treatment. We constructed the luciferase reporter genes after the promoters of PRL and GH and found the activation of both promoters by the CPT-cAMP treatment. We confirmed that overexpression of the catalytic subunit of cAMP-dependent protein kinase had essentially the same effects on MAP kinase activation and synthesis of PRL and GH as the CPT-cAMP treatment. Furthermore, treatment of the cells with pituitary adenylate cyclase-activating polypeptide 27 activated MAP kinase. The activation of PRL promoter by CPT-cAMP and pituitary adenylate cyclase-activating polypeptide 27 was abolished by pretreatment with PD098059 and H89. Although the increase in PRL and GH secretion by CPT-cAMP was inhibited by H89, PD098059 had no effect on secretion. These results suggest that cAMP-induced MAP kinase activation is essential for PRL gene expression, but not for secretion of PRL and GH.

Animals↗
PubMed2001

Effects of dermatan and dextran sulfates on arginine amidase activity released from isolated rabbit arteries.

We examined the levels of arginine amidase secreted from isolated rabbit arteries treated with dermatan and dextran sulfates, and the relation between the secretion of arginine amidase activity and the concentration of dermatan sulfate added to these arteries. The results showed that while dextran sulfate tended to accelerate the release of arginine amidase activity from the isolated rabbit ear artery, the induction was not significant. There was a significant increase in the level of arginine amidase released from the lower portion of isolated rabbit aorta (p<0.05), but no significant change in the upper portion of the aorta. In contrast, the addition of dermatan sulfate significantly increased the level of arginine amidase activity released from the isolated rabbit ear artery and the upper and lower portions of the aorta (p<0.05). Linear dose-response relationships were observed between the level of arginine amidase activity released from the isolated rabbit ear artery and aorta and the concentration of dermatan sulfate added.

Animals↗
PubMed2001

Males in rural Bangladeshi communities are more susceptible to chronic arsenic poisoning than females: analyses based on urinary arsenic.

Spot urine samples were collected from the inhabitants of two rural communities in northwestern Bangladesh. We compared arsenic levels in the urine samples ([As](u); n = 346) with those in water from tube wells ([As](tw); range < 1-535 microg/L; n = 86) on an individual basis. The small variation of [As](u) within subjects and highly positive correlation with [As](tw) indicate that [As](u) is a useful indicator of exposure. Analyses of [As](u) showed that creatinine correction was necessary, that [As](u) only reflected recent exposure, and that there were substantial interindividual differences for a given [As](tw) level. To evaluate the toxic effects of arsenic exposure, we constructed a system for rating skin manifestations, which revealed distinct sex-related differences. Comparison of males and females in the same households confirmed that skin manifestations were more severe in the males, and in the males of one community a dose-response relationship between [As](u) and the degree of skin manifestation was evident. The results of this study indicate that [As](u) in spot urine samples can be used as an exposure indicator for As. They suggest that there might be sex-related, and perhaps community-related, differences in the relationship between [As](u) and skin manifestations, although several confounding factors, including sunlight exposure and smoking habits, might contribute to the observed sex difference. The existence of such differences should be further confirmed and examined in other populations to identify the subpopulations sensitive to chronic arsenic toxicity.

Adult↗
PubMed2001

Myosin light chain phosphorylation is correlated with cold-induced changes in platelet shape.

Chilling induces shape changes in platelets from disks to spheres with abundant filopodia. Such changes were time-dependent and correlated well with the phosphorylation of 20-kDa myosin light chain (LC20). Both the shape changes and the phosphorylation were reversible. After the platelets had been chilled, myosin became incorporated into the Triton X-insoluble fraction. When the chilled platelets were immunocytochemically stained, anti-myosin antibody was localized with filamentous structures inside the filopodia. These results suggest that LC20 phosphorylation and subsequent interactions with actin filaments play a crucial role in the cold-induced changes in platelet shape and in the formation of filopodia.

Blood Platelets↗
PubMed2001

Expression of multidrug resistance associated transporters (MDR1, MRP1, LRP and BCRP) in porcine oocyte.

Transporters such as P-glycoprotein (MDR1), multidrug resistance protein 1 (MRP1), lung resistance-related protein (LRP) and breast cancer resistance protein (BCRP) are associated with multidrug resistance in various carcinoma cell lines. The expression of these molecules has been also characterized in human normal tissues. However, the expression of these molecules in oocyte is still unclear. In order to obtain more insight into the physiological role of these transporters, their expression in porcine oocyte were examined by reverse transcriptase-polymerase chain reaction. MDR1, MRP1 and LRP genes, but not BCRP gene were found to be expressed in porcine oocyte. After the subcloning and sequence analysis of MDR1, MRP1 and LRP genes, the high homology of these transporters were observed between porcine and human gene. These findings suggest that MDR1, MRP1 and LRP play an important physiological role(s) in an oocyte.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

p73 is highly expressed in myoepithelial cells and in carcinomas with metaplasia.

p73, a homologue of p53 gene, is expressed in several normal tissues including central nervous system, but data regarding tumors are scant. In this study, we have analyzed the status and expression of the p73 gene in primary breast tumors, as well as 4 normal salivary glands, 2 carcinomas with metaplasia and mixed tumors. We found that periductal myoepithelial cells of all of the mammary gland examined were clearly stained with the specific anti-p73 antibody. Furthermore, we found the expression of p73 in the neoplastic myoepithelial cells in carcinomas with metaplasia and in mixed tumors. The findings in the present study provide valuable information on the characteristics of myoepithelial cells.

Breast↗
PubMed2001

Exogenous expression of E-cadherin in gallbladder carcinoma cell line G-415 restores its cellular polarity and differentiation.

E-cadherin (E-cad) is critical for the development and maintenance of polarity and differentiation of epithelial cells. Our previous study revealed gallbladder (GB) cancer cell lines expressing E-cadherin could form cystic or spheroid-like structures in a 3-D matrix. This differentiated phenotype was disrupted by addition of anti-E-cad antibody. By extrapolation, we postulated that E-cad might directly regulate epithelial morphogenesis in GB carcinoma. In the present study, we introduced an expression plasmid harboring mouse E-cad cDNA (pBATEM2) into an undifferentiated GB cancer cell line (G-415) which did not express E-cad. We systemically compared differences including cell phenotype, morphogenesis, and ultrastructure between the parental G-415 cells (parental-cells) and E-cad transfected cells (E-cad-cells) under various conditions such as monolayer culture, 3-D gel culture as well as inoculation of nude mice. In contrast to parental-cells, E-cad-cells presented a typical epithelial shape with tight intercellular connections in monolayer culture. They developed round multicellular cystic structures in 3-D gel. The cysts secreted mucous substances via the apical surface into the cystic lumen, in which the substances were positively stained by alcian blue (pH 2.5). Ultrastructural sections of gel/xenograft tumor revealed re-establishment of adherens junctions and restoration of cell polarization. Immunohistochemical and immunofluorescent staining showed exogenous E-cad primarily accumulated at the extended cell-cell contact sites. Moreover, the membranous translocation of alpha-, and beta-catenin from cytoplasm was also found in 3-D matrix and xenograft tumor sections. Histopathologic examination revealed papillary adenocarcinoma features in the central region of the xenograft tumors. Our results demonstrate that exogenous expression of E-cad in undifferentiated GB cancer G-415 cells reverses differentiated characteristics in spatial growth conditions. Simultaneous translocation of alpha-, beta-catenin to membrane following functional E-cad expression may be a critical event for this process.

Adenocarcinoma, Papillary↗
PubMed2001

Effect of experimental fluoride-releasing tooth separator on acid resistance of human enamel in vitro.

This study aimed to investigate the fluoride-releasing ability of an experimental tooth separator consisting of polyurethane elastomer with tin fluoride and its effect on the acid resistance of human enamel. The tooth separator was set around an enamel slab and stored in de-ionized water for 10 days. The daily concentration of fluoride in the de-ionized water was measured. Then the enamel surface was artificially decalcified by a lactic acid buffer solution (pH 4.5) for 96 hours. The mineral density at the surface layer of the enamel was measured to evaluate the acid resistance. The fluoride release increased with the amount of fluoride in the separator, but decreased with the immersion time. Both the enamel area contacting with the separator and its surrounding area showed lower mineral loss and lesion depth compared with the controls (P < 0.05). It is suggested that the experimental tooth separator would release enough fluoride and improve the acid resistance of the enamel surface layer.

Absorptiometry, Photon↗
PubMed2001

Femoral vein valve repair with angioscopy-assisted anterior valve sinus plication. Early results.

BACKGROUND: The efficiency of angioscopy-assisted anterior valve sinus plication for primary deep venous insufficiency was evaluated. METHODS EXPERIMENTAL DESIGN: retrospective, clinical study with short follow-up. SETTING: institutional practice. PATIENTS: 15 limbs in 12 patients had class 4 or higher disease (SVS/ISCVS classification). Descending venography showed class 3 or 4 reflux in all patients. Venous refilling time (VRT) was abnormal (<15 sec) in all of the nine limbs in which photoplethysmography was conducted. The limbs were treated with angioscopy-assisted anterior valve sinus plication of the superficial femoral vein. Postoperative descending venography was performed between the first and third day after operation. Clinical evaluation and VRT measurement were repeated when the patients were discharged and checked at the outpatient office. RESULTS: Mean follow-up was 22 weeks with a range of 1 to 70 weeks. At postoperative descending venography, the reflux of the superficial femoral vein was significantly improved. At final follow-up, all patients reported greater or lesser relief of subjective symptoms. In four limbs with class 6 disease, ulcers healed and did not recur. In one limb with class 5 disease, ulcers did not recur. In the other 10 limbs with class 4 disease, a distinct clinical improvement occurred with resolution of skin changes. VRT was normal in 11 of the 12 limbs examined. CONCLUSIONS: Our preliminary experience demonstrates that angioscopy-assisted anterior valve sinus plication gives early good clinical and hemodynamic improvement in patients with primary deep venous insufficiency.

Adult↗
PubMed2001

Expression of the Endostatin gene in epithelial ovarian cancer.

Endostatin, a M(r) 20,000 COOH-terminal fragment of collagen XVIII, is currently in preclinical development as a novel antiangiogenic agent. The gene expression of this molecule in 23 normal ovaries with follicle or corpus luteum and in 64 cases of epithelial ovarian cancer (27 serous, 18 mucinous, 13 endometrioid, 4 clear cell, and 2 undifferentiated carcinomas) was analyzed by PCR of RNA after reverse transcription. Seven of the cases were of low malignant potential. With regard to staging, 23 cases had stage I disease, 5 had stage II disease, 29 had stage III disease, and 7 had stage IV disease. The level of endostatin gene expression was described in terms of the ratio of the relative yield of the endostatin gene to that of the beta2-microglobulin gene. Endostatin gene expression in ovarian cancers (median, 0.14; range, 0.02-1.11) was significantly higher than that in normal ovaries with follicle or corpus luteum (median, 0.08; range, 0.03-0.26; P = 0.009). International Federation of Gynecology and Obstetrics stage (P = 0.009) and residual tumor (P = 0.005) were significantly associated with endostatin gene expression; however, other clinicopathological features (e.g., patient age at diagnosis, histological subtype, and histological grade) were not significantly associated with endostatin gene expression. Survival data were available for all patients. Univariate Cox regression analysis showed the prognosis of the patients with high endostatin gene expression [equal to or greater than the median (> or =0.14)] to be significantly worse than that of patients with low endostatin gene expression [less than the median (<0.14); P = 0.044]. Our results with regard to the gene expression of this endogenous inhibitor of angiogenesis present a new insight to understand the biology of epithelial ovarian cancer and may lead to the development of a new therapeutic strategy for epithelial ovarian cancer.

Collagen↗