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Biomedical subjects

Y Miyagi

Publications and source records attributed to Y Miyagi.

At least 91 records · Page 5Linked to original sources
PubMed1997

Governing step of metastasis visualized in vitro.

Metastasis is the ultimate life-threatening stage of cancer. The lack of accurate model systems thwarted studies of the metastatic cell's basic biology. To follow continuously the succeeding stages of metastatic colony growth, we heritably labeled cells from the human lung adenocarcinoma cell line ANIP 973 with green fluorescent protein (GFP) by transfection with GFP cDNA. Labeled cells were then injected intravenously into nude mice, where, by 7 days, they formed brilliantly fluorescing metastatic colonies on mouse lung [Chishima, T., Miyagi, Y., Wang, X., Yang, M., Tan, Y., Shimada, H., Moossa, A. R. & Hoffman, R. M. (1997) Clin. Exp. Metastasis 15, 547-552]. The seeded lung tissue was then excised and incubated in the three-dimensional sponge-gel-matrix-supported histoculture that maintained the critical features of progressive in vivo tumor colonization while allowing continuous access for measurement and manipulation. Tumor progression was continuously visualized by GFP fluorescence in the same individual cultures over a 52-day period, during which the tumors spread throughout the lung. Histoculture tumor colonization was selective for lung cancer cells to grow on lung tissue, because no growth occurred on histocultured mouse liver tissue, which was also observed in vivo. The ability to support selective organ colonization in histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis [Kuo, T.-H., Kubota, T., Watanbe, M., Furukawa, T., Teramoto, T., Ishibiki, K., Kitajima, M., Moossa, A. R., Penman, S. & Hoffman, R. M. (1995) Proc. Natl. Acad. Sci. USA 92, 12085-12089]. The results presented here provide significant, new opportunities to understand and to develop treatments that prevent and possibly reverse metastasis.

Adenocarcinoma↗
PubMed1997

Amplification of the mdm-2 gene and p53 abnormalities in uterine sarcomas.

The aim of this study is to address the role of mdm-2-gene amplification in the tumorigenesis of uterine sarcomas. Differential PCR with DNA from formalin-fixed paraffin-embedded specimens was employed in 12 patients with uterine sarcomas. We detected mdm-2-gene amplification in 4 out of 12 uterine sarcomas. The estimated copy number of the mdm-2 gene ranged from 4 to 13. Positive cases included 1 leiomyosarcoma and 3 carcinosarcomas, however, there was no correlation between mdm-2-gene amplification and clinicopathological characteristics. Over-expression of p53 protein was also immunohistochemically studied in the same series of patients: 4 out of 8 carcinosarcomas displayed p53 immunoreactivity. Taking these results together, only one carcinosarcoma was found to have both mdm-2-gene amplification and p53 over-expression. In contrast, half of the patients were found to have alterations either of mdm-2 or of p53. These findings support the notion that mdm-2-gene amplification might be an alternative mechanism for escaping from the regulatory pathway of p53 to suppress cell growth.

Adult↗
PubMed1997

Expression of trypsin in vascular endothelial cells.

Proteinases produced by vascular endothelial cells are expected to play important roles in many biological processes. Here we report that human vascular endothelial cells express trypsinogen-2 mRNA and its protein product in culture. The trypsinogen production was stimulated by a tumor promoter and associated with cell growth. In situ hybridization analysis showed that the trypsinogen gene was significantly expressed in vascular endothelial cells around gastric tumors and in patients with disseminated intravascular coagulation (DIC). These results suggest the possible roles of endothelial cell-derived trypsin in tumor angiogenesis and abnormal blood coagulation.

Cells, Cultured↗
PubMed1997

Cancer invasion and micrometastasis visualized in live tissue by green fluorescent protein expression.

We report the establishment of stable, high-level green fluorescent protein (GFP)-expressing cell lines in vitro that permit the detection and visualization of distant micrometastases when they are implanted orthotopically in nude mice. Chinese hamster ovary cells were transfected with the dicistronic expression vector containing the humanized GFP cDNA. A stable GFP-expressing clone was selected in 1.5 microM methotrexate in vitro and injected s.c. in nude mice. Stable high-level expression of GFP was maintained in the s.c. growing tumors. To use GFP expression for metastasis studies, fragments of s.c. growing tumor, which are comprised of GFP-expressing cells, were implanted by surgical orthotopic implantation in the ovary of nude mice. Subsequent micrometastases were detected in systemic organs and could be visualized by GFP fluorescence in the lung, liver, and other organs down to the single-cell level. With this fluorescent tool, we detected and visualized for the first time tumor cells at the microscopic level in fresh viable tissue in their normal host organ. Confocal microscopy further enabled us to study physiologically relevant patterns of invasion and micrometastasis.

Animals↗
PubMed1997

Advanced endometrial cancer detected at 7 months after childbirth.

It is very rare to find endometrial cancers arising within a short period following childbirth, presumably because pregnancy has a protective effect against endometrial cancer mediated by elevated secretion of progesterone. We present the case of a 30-year-old Japanese woman with stage IIIC endometrial cancer that was found 7 months after childbirth. The patient was treated with surgery followed by 6 cycles of intravenous combination chemotherapy and oral administration of medroxyprogesterone acetate. Histopathological examination of surgical specimen revealed poorly differentiated adenosquamous carcinoma of the endometrium with deep myometrial invasion, cervical stromal involvement, and pelvic and paraaortic lymph node metastases. The disease progressed rapidly and the patient died of the disease.

Adult↗
PubMed1997

Adult ganglioneuroblastoma of the anterior mediastinum.

A case of ganglioneuroblastoma occurring in the anterior mediastinum of a 79 year-old man is reported. The tumor was mainly composed of neuroblasts with occasional ganglion cells. Foci of melanin-laden cells were also identified. Immunohistochemistry revealed that the tumor cells showed both schwannian and melanocytic differentiation with immunoreactivity to anti-S100 protein and anti-HMB45 antibodies. In addition, the tumor contained several microcysts lined by squamous epithelial and one lymphoid tissue abundant in T lymphocytes, which appeared to be derived from thymic tissue. This case is unique in that neuroblastoma group tumors including ganglioneuroblastoma is uncommon in the elderly and in the thymic region, and rarely shows melanocytic differentiation. To the best of our knowledge, this case is a tumor of neuroblastoma group occurring in the eldest patient.

Aged↗
PubMed1997

Metastatic patterns of lung cancer visualized live and in process by green fluorescence protein expression.

We demonstrate here the visualization of human lung cancer metastasis live and in process in nude mice by green fluorescent protein (GFP) expression. The human lung adenocarcinoma cell line Anip 973 stably transfected with the humanized GFP-S65T cDNA was selected for very bright green fluorescence. GFP-transfected lung cancer cells were initially inoculated subcutaneously in nude mice. Five weeks after transplantation, the resulting tumor had reached over 1 cm in diameter and had very bright GFP fluorescence. Fragments of subcutaneous tumor were implanted onto the visceral pleura of the left lung of nude mice by surgical orthotopic implantation (SOI) of histologically-intact tissue via transverse thoracotomy. The ipsilateral resulting tumor was highly fluorescent due to GFP expression. GFP expression allowed the visualization of the advancing margin of the ipsilateral tumor into the fresh normal lung tissue. Lymphogenous and direct-seeding metastases in the pulmonary hilum, cervical lymph nodes, the mediastinum and contralateral pleural cavity and contralateral lung in the SOI-treated mice were brightly visualized by GFP expression in fresh tissue. GFP-transfected and untransfected tumor had similar metastatic characteristics suggesting that GFP expression had no effect on metastasis itself. The results with the GFP-transfected tumor cells, combined with the use of SOI, demonstrate a fundamental advance in the visualization and study of lung cancer metastasis in process.

Adenocarcinoma↗
PubMed1997

The mechanisms of the relaxation induced by vasoactive intestinal peptide in the porcine coronary artery.

1. This study was designed to investigate the mechanism of the relaxation induced by vasoactive intestinal peptide (VIP) in medial strips of the porcine coronary artery, by determining the effect on the cytosolic Ca2+ concentration ([Ca2+]i), the [Ca2+]i-force relation and the involvement of G-protein. 2. Front-surface fluorometry of fura-2 revealed that U46619, a thromboxane A2 analogue, and the high K(+)-depolarization induced increases in both the [Ca2+]i and force of the medial strips. At a steady state of contraction, the extent of an increase in [Ca2+]i induced by 100 nM U46619 was similar to that induced by 30 mM K(+)-depolarization. VIP concentration-dependently (1 nM-1 microM) induced transient decreases in both the [Ca2+]i and force of the medial strips precontracted with 100 nM U46619. The decreases in the [Ca2+]i and force induced by VIP during the contraction with U46619 were much greater than those with 30 mM K(+)-depolarization. 3. The VIP-induced decreases in the [Ca2+]i and force were attenuated by K+ channel blockers such as tetrabutylammonium (TBA: non-selective K+ channel blocker), charybdotoxin (large conductance Ca(2+)-activated K+ channel blocker), and 4-aminopyridine (4-AP: voltage-dependent K+ channel blocker). However, neither glibenclamide (ATP-sensitive K+ channel blocker) nor apamin (small conductance Ca(2+)-activated K+ channel blocker) had any significant inhibitory effect. 4. In the 30 mM K(+)-depolarized strips, pretreatment with thapsigargin, a specific Ca(2+)-ATPase inhibitor of the Ca2+ store sites, completely abolished the VIP-induced decrease in [Ca2+]i, but partially attenuated the VIP-induced decrease in force. 5. VIP shifted the [Ca2+]i-force relation of the U46619-induced contractions to the right in a concentration-dependent manner. In the alpha-toxin-permeabilized strips, VIP decreased the force development at a constant [Ca2+]i level (pCa = 6.5) in a GTP-dependent manner, which was antagonized by guanosine-5'-O-(beta-thiodiphosphate) (GDP beta S). 6. We thus conclude that VIP relaxes the coronary artery via three mechanisms: (1) a decrease in [Ca2+]i by inhibiting the Ca2+ influx presumably through the membrane hyperpolarization mediated by the activation of the large conductance Ca(2+)-activated (charybdotoxin-sensitive) K+ channels and voltage-dependent (4-AP-sensitive) K+ channels; (2) a decrease in [Ca2+]i by sequestrating cytosolic Ca2+ into thapsigargin-sensitive Ca2+ store sites; and (3) a decrease in the Ca(2+)-sensitivity of the contractile apparatus through the activation of G-protein.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Resting load and modulation of the myofilament Ca2+ sensitivity in rabbit cerebral arteries.

The effect of preload on myofilament Ca2+ sensitivity was examined using alpha-toxin permeabilization and fura-2 fluorometry in rabbit cerebral arteries. The [Ca2+]i-force curves shifted leftward at a high preload, with a decrease in median effective concentration of Ca2+ in the permeabilized artery. In the fura-2-loaded artery, the preload modulated the force without affecting [Ca2+]i levels during K+ depolarization, and a high preload moved the [Ca2+]i-force curve upward and to the left. It is thus concluded that the preload regulates the Ca2+ sensitivity of the myofilament and, therefore, may play a role in the regulation of cerebral arterial tonus and blood flow.

Actin Cytoskeleton↗
PubMed1997

Malignant melanoma of the uterine cervix: a case report.

We present case of a 57-year-old Japanese woman a 9 cm-size primary malignant melanoma of the uterine cervix. MRI demonstrated a low-signal T1-weighted spin echo image and hyperperfusion indicated by Gd-DTPA enhancement. The sequence analysis of the MTS1/CDK4I gene revealed no deletion or mutation. The results of cytological, pathological, and electron microscopy tests are also presented.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Trypsin inhibitor activity in commercial soybean products in Japan.

The effect of trypsin inhibitor (TI) in soybean on the prevention of cancer has been reported in animal studies. However, the actual intake of active TI in daily life is not known. In this experiment we measured TI activity in various soybean products and the effects of some factors of processing on the TI activity. Average TI activity in whole soybean was 4,819 U/100 g, and the average percentages of remaining activity in products against that of whole soybean were momen-tofu 2.5%, yose-tofu 3.4%, kinugoshi-tofu 4.3%, jyuten-tofu 7.9%, soymilk 13.0%, natto 0.7%, soy sauce 0.8% and miso 0.3%. By heating soymilk at 100 degrees C, TI activity decreased to 11% at 10 min and 5% at 20 min. After heating soymilk in a water-bath for 15 min at 75 and 100 degrees C, TI activity decreased to 35 and 12%, respectively. The TI activity of tofu was proportional to the remaining whey. The effects of chemicals used for the coagulation of soy protein and foam-removal on TI activity were little. The results suggest that soybean products retain 2.5-12.5% TI activity of the whole soybean and that humans are consuming some active TI in their daily lives.

Food Handling↗
PubMed1997

Radiation-induced DNA damage in tumors and normal tissues: IV. Influence of proliferation status and cell type on the formation of oxygen-dependent DNA damage in cultured cells.

Using a variety of techniques, several laboratories have recently demonstrated the feasibility of using radiation-induced DNA strand breaks and/or DNA-protein crosslinks (DPCs) to detect and/or quantify hypoxic cells in tumors and normal tissues. However, if strand breaks and/or DPCs are to be used to estimate the hypoxic fraction or the fractional hypoxic volume of tumors and normal tissues, their formation as a function of the oxygen concentration near the DNA must be relatively independent of the biological properties of these cells. In the present study, the shape of the oxygen dependence curves and the K(m) values for radiation-induced strand breaks and DPCs were measured by alkaline elution for proliferative (P) and quiescent (Q) cells of the mouse mammary adenocarcinoma, line 66. The sigmoidal shape of the oxygen dependence curves, the K(m) for strand breaks (approximately 0.027 mM) and the K(m) for the formation of DPCs (approximately 0.020 mM) were identical for the P and Q cells of line 66. Consequently, the proliferative status of these tumor cells had no measurable influence on the oxygen-dependent formation of radiation-induced strand breaks and DPCs. In addition, the percentage of the DNA retained on the filters after approximately 24 ml of elution without proteinase K in the lysis solution, a parameter equal to the sum of the strand breaks and DPCs that has been shown to be proportional to the percentage of hypoxic cells in the sample, was not significantly different for fully oxygenated or fully hypoxic populations from five tumor cell lines that varied in species, site of origin, proliferative status and/or properties of the proteins which are intimately associated with their DNA. These data indicate that the formation of radiation-induced strand breaks and DPCs depends predominantly on the oxygen concentration in the microenvironment around the DNA, and only minimally on the biological properties of the cells.

Adenocarcinoma↗
PubMed1997

Identification of integrin-dependent and -independent cell adhesion domains in COOH-terminal globular region of laminin-5 alpha 3 chain.

Laminin-5 is an isoform of laminin that consists of alpha 3, beta 3, and gamma 2 chains and has potent cell adhesion- and cell migration-promoting activities. In this study, five subdomains in the COOH-terminal globular (G) domain of human laminin alpha 3 chain were individually expressed in Escherichia coli, and their biological activities were investigated. Recombinant G2, G4, and G5 domains promoted adhesion to plastic plates of HT1080 fibrosarcoma cells, A431 epidermoid carcinoma cells, and ECV304 vascular endothelial cells. For the cell adhesion activity, the G2 domain required a divalent cation and heat-sensitive conformation more strongly than G4 and G5. The cell adhesion to G2 but not G4 and G5 was effectively inhibited by an anti-integrin alpha 3 antibody. A cell adhesion sequence of 22 amino acids, alpha 3G2A, that was homologous to the integrin alpha 3 beta 1-binding sequence GD-6 of laminin alpha 1 chain was identified within the G2 structure. The cell adhesion to alpha 3G2A peptide was also inhibited by the anti-integrin alpha 3 antibody. The cell adhesion to G2, alpha 3G2A, G4, and G5 was strongly inhibited by heparin, but that to native laminin-5 was inhibited less effectively. Moreover, G5 potently stimulated chemotactic migration of rat liver epithelial cells in Boyden chambers, but G2 and G4 did not. These results indicate that the G domain of laminin alpha 3 contains multiple cell binding sites with different mechanisms and different functions. The G2 domain seems to recognize integrin alpha 3 beta 1, whereas G4 and G5 may interact with heparin-like molecules on cell surface.

Animals↗
PubMed1997

Determination of hepatitis delta virus (HDV)-RNA in asymptomatic cases of HDV infection.

OBJECTIVES: To assess the frequency of hepatitis delta virus (HDV) viremia in asymptomatic cases of HDV infection and the clinical significance of the HDV viremia, we conducted a cross-sectional, community-based study. METHODS: Of 2207 examinees, 210 (9.5%) were found to be positive for hepatitis B surface antigen (HBsAg). Antibody to HDV was detected in 47 (22.4%) of the 210 examinees, and 43 of the 47 were further evaluated for serum HDV-RNA by polymerase chain reaction. RESULTS: Twenty-one (48.8%) of the 43 had detectable levels of HDV-RNA in serum, and 22 (51.2%) were negative for serum HDV-RNA. The majority (61.9%) of the HDV-RNA-positive HBsAg carriers had high levels of serum ALT. In contrast, the frequency of an abnormally high level of serum ALT was only 9.1% in the HBsAg carriers positive for HDV antibody but negative for HDV-RNA, and the frequency did not differ from that seen in the HBsAg-negative individuals. The semiquantified HDV-RNA levels did not correlate with the serum ALT levels. CONCLUSION: Seropositivity of HDV-RNA was strongly associated with liver cell damage, even in asymptomatic cases. The absence of a detectable level of serum HDV-RNA might be related to previous HDV infection.

Adult↗
PubMed1996

Regional distribution of heparin-binding epidermal growth factor-like growth factor mRNA and protein in adult rat forebrain.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a recently described member of the EGF family that binds to and stimulates phosphorylation of the EGF receptor (EGFR). In this study, we examined the cellular localization of HB-EGF gene transcripts and protein in adult rat forebrain. In situ hybridization studies showed that neurons in various regions, including cortex, hippocampus, and deep structures, express HB-EGF mRNA. Positively labeled cells were also present in white matter, which suggests that both neurons and glia express HB-EGF mRNA. Immunohistochemical studies with an antibody specific to proHB-EGF, a transmembrane form of HB-EGF, demonstrated ubiquitous immunoreactivity in neurons and glial cells in white matter. In view of the wide expression of its cognitive receptor, EGFR, in central nervous system neurons, our results suggest that HB-EGF is an endogenous ligand for EGFR in the central nervous system and may play an important role in physiological conditions.

Animals↗
PubMed1996

Vitamin E deficiency in variant angina.

BACKGROUND: Oxidative modification of LDL has been suggested to increase coronary vasoreactivity to agonists. A deficiency of vitamin E, a major antioxidant, may be related to the occurrence of coronary artery spasm. METHODS AND RESULTS: Vitamin E levels were determined with the use of high-performance liquid chromatography in normolipidemic subjects, including 29 patients with active variant angina (group 1), 13 patients with inactive stage of variant angina without anginal attacks during the past 6 months (group 2), 32 patients with a significant (>75%) organic coronary stenosis and stable effort angina (group 3), and 30 patients without coronary artery disease (group 4). Total lipid levels in blood were calculated as total cholesterol plus triglyceride levels. The plasma alpha-tocopherol levels as well as alpha-tocopherol/lipids were significantly lower in group 1 than in groups 2 through 4. Also, the plasma gamma-tocopherol levels were significantly lower in group 1 than in groups 2 through 4. The vitamin E levels were not significantly different between group 1 patients with and those without a significant organic stenosis. In group 1, both alpha- and gamma-tocopherol levels were significantly elevated after a > or = 6-month angina-free period. The alpha-tocopherol levels in the LDL fraction were significantly lower in group 1 than in group 4. Plasma alpha-tocopherol levels were significantly correlated with those in the LDL fractions. In 6 patients of group 1 still having anginal attacks while receiving calcium channel blockers, the addition of vitamin E acetate (300 mg/d) significantly elevated plasma alpha-tocopherol levels and inhibited the occurrence of angina. CONCLUSIONS: Plasma vitamin E levels were significantly lower in patients with active variant angina than in subjects without coronary spasm, suggesting an association between vitamin E deficiency and coronary artery spasm.

Angina Pectoris↗
PubMed1996

P2U purinergic activation leads to the cell cycle progression from the G1 to the S and M phases but not from the G0 to G1 phase in vascular smooth muscle cells in primary culture.

The regulation of the cell cycle by extracellular UTP was investigated in rat aortic smooth muscle cells in primary culture (VSMCs) by means of an immunocytochemical analysis of cell cycle-specific nuclear antigens. UTP induced a rise in the cytosolic Ca2+ concentration ([Ca2+]i) of VSMCs, which was desensitized by pretreatment with ATP, but not with 2-methylthioATP nor alpha, beta-methyleneATP. The incubation of serum-deprived G0 cells with platelet derived growth factor (PDGF) induced cell cycle progression into the G1 phase without any further progression into the S and M phases, while none of the nucleotides had any effect on the cell cycle of the G0 cells. The incubation of the PDGF-pretreated cells at the G1 phase with 2-methylthioATP or alpha, beta-methyleneATP had no effect on the cell cycle of G1 cells, while the incubation of the G1 cells with UTP, ATP, and ATP gamma S stimulated cell cycle progression into the S and M phases. These results thus indicate that P2U purinergic activation mediates a [Ca2+]i transient and a progression growth factor effect of nucleotides in VSMCs.

Adenosine Triphosphate↗