Biomedical subjects

Y Funahashi

Publications and source records attributed to Y Funahashi.

16 recordsLinked to original sources

PubMed2001

Effect of E7010 on liver metastasis and life span of syngeneic C57BL/6 mice bearing orthotopically transplanted murine Colon 38 tumor.

PURPOSE: E7010 is an orally active sulfonamide antitumor agent showing good activity against various subcutaneously inoculated rodent tumors and human tumor xenografts. The purpose of this study was to evaluate the effect of E7010 on liver metastasis and life span of mice bearing orthotopically transplanted murine Colon 38 tumor. METHODS: Orthotopic transplantation of murine Colon 38 tumor as intact tissue yielded hepatic metastasis with a high incidence in about 1 month in C57BL/6 mice, and the mice died in about 2 months with cachexia. In this model, the maximum tolerated dose of E7010 (100 mg/kg per day) was administered orally on various schedules, including for 14 days or daily until death, starting at 14 days after transplantation, or for 8 days from 21 days after transplantation. RESULTS: E7010 showed tumor growth inhibition (T/C=40%) at the orthotopic site similar to that at the subcutaneous site (T/C = 32%) when administered from 14 days after transplantation. When E7010 was started from 21 days after transplantation, it significantly decreased the number of hepatic metastases (control 17.1+/-20.8, E7010 2.6+/-5.3), although inhibition of tumor growth at the orthotopic site was only moderate (T/ C=60%). The administration of E7010 until death produced a significant increase in life span (control 49.8+/-8.9 days, E7010 62.5+/-6.1 days). Although the tumor weight of the E7010-treated group on the day of death was similar to that of the untreated group (control 1.166+/-0.507 g, E7010 1.211+/-0.632 g), there were significantly fewer liver metastases in the E7010-treated group (control 41.3+/-31.1, E7010 2.0+/-2.0). CONCLUSION: E7010 suppressed tumor growth at both primary and metastatic sites and increased life span in an orthotopic transplantation model of murine Colon 38 tumor in syngeneic C57BL/6 mice. Hepatic metastasis was inhibited more effectively than the growth of the primary tumor.

Aminophenols↗

PubMed2000

Luminacins: a family of capillary tube formation inhibitors from Streptomyces sp. I. Taxomony, fermentation, isolation, physico-chemical properties and structure elucidation.

A new family of capillary tube formation inhibitors, designated luminacins, has been discovered in the fermentation broth of a soil bacterium. The strain was identified as Streptomyces sp. Mer-VD1207 from taxonomic studies. By means of a series of chromatographic procedures, fourteen structurally related components, luminacins A1, A2, B1, B2, C1, C2, D, E1, E2, E3, F, G1, G2, and H, were isolated, and their structures were elucidated on the basis of spectroscopic analyses.

Angiogenesis Inhibitors↗

PubMed2000

Luminacins: a family of capillary tube formation inhibitors from Streptomyces sp. II. Biological activities.

Twelve of the fourteen isolated components of the luminacin family were assayed for activity to inhibit capillary tube formation in vitro. Seven of them showed potent activity with IC50 values of less than 0.1 microg/ml in a rat aorta matrix culture model. Luminacin D, the strongest inhibitor, inhibited both endothelial cell proliferation and capillary tube formation. Morphological observation suggested that luminacin D inhibited the rearrangement of endothelial cells in the initial stage of tube formation. Luminacins and their derivatives are good candidates for application as angiogenesis inhibitors with a novel mechanism of action.

Angiogenesis Inhibitors↗

PubMed1999

Rapid development of hepatic metastasis with high incidence following orthotopic transplantation of murine colon 38 carcinoma as intact tissue in syngeneic C57BL/6 mice.

BACKGROUND AND OBJECTIVES: Orthotopic transplantation of human colon tumors was a useful method for producing hepatic metastasis in mice. In many cases, however, it took about 3 months for evaluation. We examined an in vivo model of hepatic metastasis for only 4 weeks by conducting orthotopic transplantation of murine Colon 38 tumor using intact tissue in syngeneic mice and determined the efficacy of chemotherapeutic agents against hepatic metastasis. METHODS: Twenty milligrams of tumor tissues were prepared from subcutaneously (s.c.) growing Colon 38 tumor and orthotopically transplanted on the cecum in C57BL/6 mice. Mice were autopsied about 4 weeks after transplantation. Metastases to various organs were detected macroscopically or histochemically and tumor invasion into the cecum was observed histochemically. In experimental chemotherapy, mice bearing orthotopically transplanted Colon 38 tumor were separated into three equal groups and were either treated with fluorouracil or cisplatin (CDDP), or untreated. Four weeks after transplantation, activities of both agents against local tumor growth and hepatic metastasis were evaluated. RESULTS: Macroscopic metastases to various organs including the liver, the lung, and the peritoneum were developed during days 28 to 32 after inoculation. The frequency of hepatic metastasis was 96% (N = 23). Histological examination indicated that the local tumor invaded various layers of the cecum and metastasized to the liver and lung hematogenously. In experimental chemotherapy with fluorouracil and CDDP, only fluorouracil decreased the incidence of mice with hepatic metastasis (2/8 cases), compared with vehicle treatment (7/8 cases) and the number of metastatic nodules in the liver (P = 0.016), although the inhibition against local growth of CDDP in T/C [45%; mean tumor weight of the test group (T) compared with that of the control group (C)] was similar to that of fluorouracil (53%). CONCLUSIONS: This model, with its rapid development of hepatic metastasis in high frequency, should be useful as a screening assay to find anti-metastatic agents for colorectal carcinoma.

Adenocarcinoma↗

PubMed1999

[Effects of gadobenate dimeglumine on MRI of mouse liver metastasis model constructed by orthotopic transplantation of highly metastatic murine colon carcinoma (C38-OT7): comparison with gadopentetate dimeglumine].

Twelve mice with metastatic liver tumors were divided into two groups of six, with one group administered contrast medium at 0.1 mmol/kg, and the other at 0.2 mmol/kg. Contrast medium, gadobenate dimeglumine (GD) or gadopentetate dimeglumine (GP), was administered at 0.1 or 0.2 mmol/kg via the tail vein to each animal in each group. Using a Signa Horizon 1.5-Tesla MRI unit, spin-echo transverse and coronal T1-weighted sections were obtained every 15 minutes until 2 hours after administration. The numbers of liver tumors detected on films were counted before and after the administration of contrast medium, and the liver/tumor contrast-to-noise ratio (CNR) was calculated. After the completion of MRI, livers were removed, and the number of metastatic nodules on the liver surface were counted as the number of tumors. Liver/tumor CNR rose after administration in both of the GD groups. In the GP group, liver/tumor CNR remained almost constant throughout the observation period. Relative to the number of tumors detected at optical microscopy, approximately 80% and 100% of tumors were detected at MRI after the administration of GD at 0.1 and 0.2 mmol/kg, respectively. On the other hand, approximately similar numbers of tumors were detected at MRI before and after the administration of GP. These results suggest that GD administered by intravenous injection was transported promptly to the liver, increased liver/tumor CNR, and enhanced detection performance for metastatic liver tumor.

Animals↗

PubMed1999

Establishment of a quantitative mouse dorsal air sac model and its application to evaluate a new angiogenesis inhibitor.

We have developed an improved mouse dorsal air sac model for quantifying in vivo tumor-induced angiogenesis. In our improved model, tumor angiogenesis is determined by measuring the blood volume in an area of skin held in contact with a tumor cell-containing chamber, using 51Cr-labeled red blood cells (RBC). The blood volume induced by murine B16-BL6 melanoma cells increased linearly with the cell number in the range from 2 x 10(5) to 5 x 10(6). Ten of 11 human tumor cell lines examined induced a significant increment in blood volume. For three representative human tumor cell lines (A549, WiDr. and HT1080 cells) that showed different angiogenic potencies, the levels of vascular endothelial growth factor (VEGF) produced by the tumor cells cultured under conditions of hypoxia and high cell density were correlated with the degree of in vivo angiogenesis. Using the improved model, it was confirmed that TNP-470, a well-known inhibitor, and borrelidin, an antibiotic from Streptomyces rochei, significantly inhibited the WiDr cell-induced angiogenesis. Borrelidin also inhibited spontaneous lung metastasis of B16-BL6 melanoma at the same dose that inhibited angiogenesis. Our results suggest that the improved mouse dorsal air sac model can be used for simple and quantitative measurement of tumor-induced angiogenesis and its inhibition.

Angiogenesis Inhibitors↗

PubMed1998

Bcl-2 prevents apoptotic mitochondrial dysfunction by regulating proton flux.

We and others have recently shown that loss of the mitochondrial membrane potential (Deltapsi) precedes apoptosis and chemical-hypoxia-induced necrosis and is prevented by Bcl-2. In this report, we examine the biochemical mechanism used by Bcl-2 to prevent Deltapsi loss, as determined with mitochondria isolated from a cell line overexpressing human Bcl-2 or from livers of Bcl-2 transgenic mice. Although Bcl-2 had no effect on the respiration rate of isolated mitochondria, it prevented both Deltapsi loss and the permeability transition (PT) induced by various reagents, including Ca2+, H2O2, and tert-butyl hydroperoxide. Even under conditions that did not allow PT, Bcl-2 maintained Deltapsi, suggesting that the functional target of Bcl-2 is regulation of Deltapsi but not PT. Bcl-2 also maintained Deltapsi in the presence of the protonophore SF6847, which induces proton influx, suggesting that Bcl-2 regulates ion transport to maintain Deltapsi. Although treatment with SF6847 in the absence of Ca2+ caused massive H+ influx in control mitochondria, the presence of Bcl-2 induced H+ efflux after transient H+ influx. In this case, Bcl-2 did not enhance K+ efflux. Furthermore, Bcl-2 enhanced H+ efflux but not K+ flux after treatment of mitochondria with Ca2+ or tert-butyl hydroperoxide. These results suggest that Bcl-2 maintains Deltapsi by enhancing H+ efflux in the presence of Deltapsi-loss-inducing stimuli.

Animals↗

PubMed1997

Involvement of caspase-4(-like) protease in Fas-mediated apoptotic pathway.

Proteases of the caspase family, especially caspase-1 (ICE)(-like), caspase-3 (CPP32/Yama/apopain)(-like) and caspase-8 (MACH/FLICE/Mch5) proteases, are implicated in Fas (APO-1/CD95)-mediated apoptosis. Here, we show that the caspase-4 (TX/ICH-2/ICE(rel)II)(-like) protease, another member of the caspase family, is also involved in Fas-mediated apoptosis, based upon the observations: (i) caspase-4 is processed in response to an agonistic anti-Fas antibody treatment, (ii) overexpression of a mutant caspase-4 with active site mutations in both p20 and p10 subunits delays Fas-mediated apoptosis, (iii) microinjected anti-caspase-4 antibodies inhibit Fas-mediated apoptosis. Together with our observations that the mutant caspase-4 inhibits the Fas-mediated activation of caspase-3(-like) proteases and purified caspase-4 cleaves pro-caspase-3 to generate a subunit of active form, these results suggest that Fas-mediated apoptosis is driven by a caspase cascade in which the caspase-4(-like) protease transmits a death signal from caspase-8 to caspase-3(-like) proteases probably through directly cleaving pro-caspase-3(-like) proteases.

Antibodies↗

PubMed1997

The role of retinal bipolar cell in early vision: an implication with analogue networks and regularization theory.

A linear analogue network model is proposed to describe the neuronal circuit of the outer retina consisting of cones, horizontal cells, and bipolar cells. The model reflects previous physiological findings on the spatial response properties of these neurons to dim illumination and is expressed by physiological mechanisms, i.e., membrane conductances, gap-junctional conductances, and strengths of chemical synaptic interactions. Using the model, we characterized the spatial filtering properties of the bipolar cell receptive field with the standard regularization theory, in which the early vision problems are attributed to minimization of a cost function. The cost function accompanying the present characterization is derived from the linear analogue network model, and one can gain intuitive insights on how physiological mechanisms contribute to the spatial filtering properties of the bipolar cell receptive field. We also elucidated a quantitative relation between the Laplacian of Gaussian operator and the bipolar cell receptive field. From the computational point of view, the dopaminergic modulation of the gap-junctional conductance between horizontal cells is inferred to be a suitable neural adaptation mechanism for transition between photopic and mesopic vision.

Animals↗

PubMed1997

Targeted expression of ced-3 and Ice induces programmed cell death in Drosophila.

CED-3 is a cysteine protease required for programmed cell death in the nematode, Caenorhabditis elegans, and shares a sequence similarity with mammalian ICE (interleukin-1beta converting enzyme) family proteases. Both CED-3 and ICE family proteases can induce programmed cell death in mammalian cells. Structural and functional similarities between CED-3 and ICE family proteases indicate that the mechanism of cell death is evolutionarily conserved, suggesting the presence of a similar mechanism involving CED-3/ICE-like proteases in Drosophila. Here we determined whether CED-3 or ICE functions to induce programmed cell death in Drosophila. We have generated transformant lines in which ced-3 or Ice is ectopically expressed using the GAL4-UAS system. Expression of CED-3 and ICE can elicit cell death in Drosophila and the cell death was blocked by coexpressing the p35 gene which encodes a viral inhibitor of CED-3/ICE proteases. Results support the idea that the mechanism of programmed cell death controlled by CED-3/ICE is conserved among widely divergent animal species including Drosophila, and the system described provides a tool to dissect cell death mechanism downstream of CED-3/ICE proteases.

Journal Article↗

PubMed1997

Caspase-4 and caspase-5, members of the ICE/CED-3 family of cysteine proteases, are CrmA-inhibitable proteases.

Proteases of the caspase family are implicated in mammalian apoptosis and constitute a protease cascade. We characterized caspase-4 (TX/ICH-2/ICErelII) and caspase-5 (ICErelIII/TY), which are most closely related to caspase-1 (ICE) among the caspase family. Although overexpression of caspase-4 and caspase-5 induced apoptosis, confirming previous observations, this apoptosis was not inhibited by a caspase-1-specific tetrapeptide inhibitor (Ac-YVAD-CHO), suggesting that caspase-4 and caspase-5 have different substrate specificities from caspase-1 and also that caspase-4- and caspase-5-induced apoptosis is not mediated by caspase-1. CrmA, a cowpox virus-derived caspase-1 inhibitor that prevents apoptosis induced by various stimuli, was cleaved by caspase-4 and caspase-5, and inhibited their proteolytic activity as assessed by cleavage of pro-caspase-3 (pro-CPP32/Yama/apopain). Thus, caspase-4 and caspase-5 are CrmA-inhibitable proteases like caspase-1 and might be involved in apoptosis.

Journal Article↗

PubMed1997

Borrelidin is an angiogenesis inhibitor; disruption of angiogenic capillary vessels in a rat aorta matrix culture model.

Borrelidin, an antibiotic from Streptomyces rochei, was found to be an angiogenesis inhibitor in a rat aorta matrix culture model which forms capillary vessels in vitro. Borrelidin strongly inhibited capillary tube formation with a 50%-inhibitory concentration value of 0.8 nM, and decreased the number of capillary tubes within 24 hours when added after maturation of tube formation. Borrelidin remarkably disrupted capillary tubes in a dose-dependent manner, by inducing apoptosis of the tube-forming cells.

Animals↗

PubMed1995

Computational studies on the interaction between red cone and H1 horizontal cell.

We propose an equivalent circuit model of a discrete formulation to describe the interaction between the red cone syncytium and the H1 horizontal cell syncytium in lower vertebrate retinas. Analytical solutions of the model provide intuitive understandings of spatio-temporal properties of light-induced responses in reference to membrane impedance, strength of chemical synapse and coupling resistance connecting neighbouring cells. Physiologically plausible values of these parameters are estimated using the solutions. Quantitative studies are made to elucidate the function of (1) the negative feedback from the H1 horizontal cell to the red cone, and (2) the resistance increase of H1 horizontal cell coupling by dopamine.

Animals↗

PubMed1994

In vivo tumor growth inhibition produced by a novel sulfonamide, E7010, against rodent and human tumors.

The search for compounds active against solid tumors has led us to the discovery of a novel sulfonamide, E7010 (N-[2-[(4-hydroxyphenyl)amino]-3-pyridinyl]-4- methoxybenzenesulfonamide), which inhibits tubulin polymerization. When administered orally, E7010 showed good antitumor activity against various rodent tumors and human tumor xenografts. In tests on mouse tumor, E7010, administered in doses of 25-100 mg/kg daily for 8 days, inhibited the growth of colon 38 carcinoma inoculated s.c. in mice by 60-99%. E7010 was active against s.c. inoculated M5076 fibrosarcoma (75% tumor growth inhibition), s.c. inoculated Lewis lung carcinoma (84% increase in life span), and i.p. inoculated P388 leukemia (118% increase in life span). In a test on rat tumor, E7010 inhibited the growth of SST-2 mammary carcinoma inoculated s.c. in rats by 84%. In tests on s.c. inoculated human tumor xenografts, E7010, when administered orally, showed a broad spectrum of activity. E7010 inhibited the growth of: four kinds of gastric cancer, H-81, H-111, SC-2, and SC-6 by 60-78%; three kinds of colon cancer, H-143, COLO320DM, and WiDr by 58-83%; three kinds of lung cancer, LC-376, LC-6, and LX-1 by 63-82%; and two kinds of breast cancer, H-31 and MX-1 by 79-87%. In studies on drug-resistant P388 leukemia, E7010 was effective against vincristine-resistant P388, cisplatin-resistant P388, and 5-fluorouracil-resistant P388 sublines in mice. Because of its good activity against rodent tumors and human tumor xenografts, E7010 is currently undergoing Phase I clinical trials.

Aminophenols↗

PubMed1991

An investigation on rheumatoid factor of different immunoglobulin classes in hepatitis B virus carriers.

Rheumatoid factor (RF) is known to be present very frequently in HB virus carriers. When RF was assayed in 140 asymptomatic carriers by agglutination method, 20.0% were found to be positive, whereas 2.7% in the controls (p less than 0.01). ELISA for detection of RF isotypes showed RF in carriers to be almost IgMRF only. IgMRF showed a tendency to react more readily to human IgG rather than to rabbit IgG. The incidence of IgMRF positivity was higher among anti-HBe antibody-positive carriers than among anti-HBe antibody negative ones, but the difference between the two populations was not significant. However, the incidence of IgMRF positivity in the group showing hepatic dysfunctions was found to be significantly higher than in the group with normal hepatic functions.

Agglutination Tests↗

PubMed1990

Analysis of PI (phosphatidylinositol)-anchoring antigens in a patient of paroxysmal nocturnal hemoglobinuria (PNH) reveals deficiency of 1F5 antigen (CD59), a new complement-regulatory factor.

FACS analysis together with PIPLC treatment was applied to PI-anchoring antigens such as DAF (decay-accerelating factor, CD55), 1F5 antigen (CD59), CD14 and CD16 on the cell surfaces of blood cells from a normal adult and a male patient with paroxysmal nocturnal hemoglubinuria (PNH). Through the extensive analysis, this patient proved to be completely defective in 1F5 antigen, a newly found complement-regulatory protein, on all the blood cells tested. In normal blood cells such as lymphocytes, monocytes and granulocytes, 1F5 antigen was expressed as one of PI-anchoring proteins. In contrast to most of PNH patients, this patient reserved DAF, CD14 and CD16 at normal levels in his erythrocytes, monocytes and granulocytes. Also, there were no significant differences between the normal adult and the patient in the activities of erythrocyte acetylcholinesterase and granulocyte alkaline phosphatase which were also known to be PI-anchoring enzymes. Thus, deficiency of 1F5 antigen must be deeply related to the clinical symptoms of PNH in this patient.

Adult↗