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Y Okada

Publications and source records attributed to Y Okada.

At least 577 records · Page 32Linked to original sources

Expression and tissue localization of membrane-types 1, 2, and 3 matrix metalloproteinases in human invasive breast carcinomas.

Activation of the zymogen of matrix metalloproteinase 2 (proMMP-2, progelatinase A) possibly is one of the key steps in invasion and metastasis of various human carcinomas. Three different membrane-type MMPs (MT-MMPs), MT1-, MT2-, and MT3-MMPs are thought to be activators of proMMP-2 in the tissues. MT4-MMP is structurally different from the other three enzymes, and its function as proMMP-2 activator is uncertain. In the present study of human invasive breast carcinomas, we examined a correlation between the expression of MT1-, MT2-, and MT3-MMPs, immunolocalization of MT1- and MT2-MMPs, and proMMP-2 activation. Northern blot analysis demonstrated the predominant expression of MT1-MMP mRNA in carcinoma tissues (20 of 20 cases), whereas MT2-MMP was detected in only 25% of the cases (5 of 20 cases), and no detectable expression of MT3-MMP was observed. The expression levels of MT1-MMP but not MT2-MMP correlated well with the presence of lymph node and distant metastases, clinical stages, and size of tumors. Immunohistochemically, MT1-MMP was localized predominantly in the carcinoma cells in all of the samples (32 of 32 cases). Immunostaining of MT2-MMP in the carcinoma cells was observed in only 38% of the cases (12 of 32 cases). Immunoblot analysis of tumor homogenates confirmed the presence of these MT-MMPs. Activation of proMMP-2 was significantly higher in the carcinoma samples with lymph node or distant metastasis compared to carcinoma without metastasis, normal control, or fibrocystic disease (P < 0.05). An increase in the activation ratio of proMMP-2 correlated directly with the expression of MT1-MMP but not MT2-MMP, as measured by either Northern blot analysis or immunostaining. These results suggest that MT1-MMP may play a key role in human breast carcinoma invasion and metastasis by being predominantly responsible for activation of proMMP-2.

Adult↗

Effects of hypothermia on the neuronal activity, [Ca2+]i accumulation and ATP levels during oxygen and/or glucose deprivation in hippocampal slices of guinea pigs.

The protective effects of mild hypothermia (33 and 29 degrees C) on the neuronal activity, intracellular Ca2+ accumulation and ATP levels during deprivation of oxygen and/or glucose were investigated using guinea pig hippocampal slices. During oxygen and glucose deprivation and oxygen deprivation only, mild hypothermia had only minor effects on the maintenance of neuronal activity and ATP levels, but it suppressed Ca2+ accumulation and drastically improved the reversibility of neuronal activity. During glucose deprivation only, mild hypothermia could maintain the neuronal activity as well as ATP levels.

Adenosine Triphosphate↗

Protein kinase C-independent correlation between P-glycoprotein expression and volume sensitivity of Cl- channel.

The possible correlation between P-glycoprotein (PGP) and volume-sensitive Cl- channel was examined in a pair of cell lines: a subline of the human epidermoid KB cell (KB-3-1) and the corresponding MDR1-transfected cell line (KB-G2). Western blot analysis and indirect immunofluorescence studies indicated that KB-G2, but not KB-3-1, exhibits the PGP expression. Patch-clamp whole-cell recordings showed that osmotic swelling activates Cl- currents not only in PGP-expressing but also in PGP-lacking cells. The amplitude of the maximal current was indistinguishable between both cells. Activation of protein kinase C (PKC) or loading with a PKC inhibitor failed to affect the swelling-induced activation of the Cl- currents in both cells. The relation between whole-cell Cl- currents and cell size measured simultaneously showed that volume sensitivity of the Cl- channel was augmented by the PGP expression irrespective of the activity of PKC on the plasma membrane. A similar increase in volume sensitivity of the Cl- channel was also induced by the expression of the ATP hydrolysis-deficient PGP mutant, K433M. We conclude that P-glycoprotein does not represent the volume-sensitive Cl- channel but that its expression modulates volume sensitivity of the Cl- channel in a manner independent of its ATPase activity or of the protein kinase C activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Doxorubicin sensitizes human bladder carcinoma cells to Fas-mediated cytotoxicity.

BACKGROUND: The resistance of bladder carcinoma to anticancer chemotherapeutic agents remains a major problem. Hence, several immunotherapeutic approaches have been developed to treat the drug-resistant cancer cells. Fas antigen (Fas) and Fas ligand participate in cytotoxicity mediated by T lymphocytes and natural killer cells. Like Fas ligand, anti-Fas monoclonal antibody (MoAb) induces apoptosis of the cells expressing Fas. This study examined whether bladder carcinoma cells are sensitive to cytotoxicity mediated by anti-Fas MoAb and whether anticancer agents synergize with anti-Fas MoAb in cytotoxicity. METHODS: Cytotoxicity was determined by a 1-day microculture tetrazolium dye assay. Synergy was assessed by isobolographic analysis. RESULTS: The T24 human bladder carcinoma cell line constitutively expressed the Fas on the cell surface; however, T24 line was resistant to anti-Fas MoAb. Treatment of T24 cells with anti-Fas MoAb in combination with mitomycin C, methotrexate, or 5-fluorouracil did not overcome their resistance to these agents. However, treatment of T24 cells with a combination of anti-Fas MoAb and doxorubicin resulted in a synergistic cytotoxic effect. In addition, the doxorubicin-resistant T24 cells were sensitive to treatment with a combination of anti-Fas MoAb and doxorubicin. Synergy was also achieved in three other bladder carcinoma cell lines and four freshly derived human bladder carcinoma cells. Treatment with anti-Fas MoAb in combination with epirubicin or pirarubicin also resulted in a synergistic cytotoxic effect on T24 cells. The mechanisms of synergy were examined. Anti-Fas MoAb did not affect the intracellular accumulation of doxorubicin, the expression of P-glycoprotein, or the expression of the antioxidant glutathione S-transferase-pi mRNA. However, treatment with doxorubicin enhanced the expression of Fas on T24 cells. CONCLUSIONS: This study demonstrated that treatment of bladder carcinoma cells with doxorubicin sensitized the cells to lysis by anti-Fas MoAb. The synergistic effect obtained with established doxorubicin-resistant bladder carcinoma cells and freshly isolated bladder carcinoma cells suggests that drug-resistant bladder carcinoma cells can be sensitized by doxorubicin to Fas- and Fas ligant-mediated cytotoxicity by lymphocytes. Furthermore, the sensitization required low concentrations of doxorubicin, thus supporting the in vivo application of a combination of chemotherapy and immunotherapy in the treatment of drug-resistant and/or immunotherapy-resistant bladder carcinoma.

Antibiotics, Antineoplastic↗

Degradation of decorin by matrix metalloproteinases: identification of the cleavage sites, kinetic analyses and transforming growth factor-beta1 release.

Decorin (DCN) is a ubiquitous proteoglycan comprised of a core protein attached to a single dermatan/chondroitin sulphate glycosaminoglycan chain. It may play a role in regulation of collagen fibrillogenesis and function as a reservoir of transforming growth factor beta (TGF-beta) in the extracellular milieu. We have examined the susceptibility of DCN to five different matrix metalloproteinases (MMPs): MMP-1 (tissue collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin 1), MMP-7 (matrilysin) and MMP-9 (gelatinase B). MMP-2 and MMP-3 digest DCN into seven major fragments in a similar pattern. The N-terminal sequence of the two fragments generated by MMP-2 and MMP-3 is Leu211-Lys-Gly-Leu-Asn, but that of the others is Asp1-Glu-Ala-Ser-Gly. MMP-7 cleaves DCN into three major fragments which have the N-termini Asp1-Glu-Ala-Ser-Gly, Glu2-Ala-Ser-Gly-Ile and Leu244-His-Leu-Asp-Asn. Activities of MMP-1 and MMP-9 against DCN are negligible. The values of Km for the MMPs capable of degrading DCN are very similar (10-12 microM), but the kcat/Km value for MMP-7 (30.5 microM-1.h-1) is 4.5-fold higher than those for MMP-2 and MMP-3. Incubation of a DCN-TGF-beta1 complex with MMP-2, -3 or -7 results in release of TGF-beta1 from the complex. These data indicate proteolytic degradation of DCN by MMP-2, MMP-3 and MMP-7, and suggest the possibility that, under pathophysiological conditions, the digestion by the MMPs may induce tissue reactions mediated by TGF-beta1 released from DCN in the connective tissues.

Amino Acid Sequence↗

Identification of the replication region of the Lactobacillus acidophilus plasmid pLA106.

The complete nucleotide sequence of plasmid pLA106 (2862 bp) from Lactobacillus acidophilus TK8912 was determined. Based on this sequence, the location of the genes for mobilization-plasmid recombination protein (mob), replication origin (ori), transcriptional repressor protein (repA) and replication initiation protein (repB) were predicted. Deletion analysis showed that the 1.4-kb PstI-EcoRV fragment carrying the ori, repA and repB genes is able to replicate in Lactobacillus and Escherichia coli cells. The plasmid pLA106 appears to have most features of the pLS1/pE194 plasmid family.

Amino Acid Sequence↗

Expression of platelet-derived endothelial cell growth factor in bladder carcinoma.

BACKGROUND: Angiogenesis is a prerequisite to cancer growth and metastasis and is induced by a variety of angiogenic factors, including platelet-derived endothelial cell growth factor (PDECGF). The authors investigated the expression of PDECGF in 58 initial primary bladder carcinomas. METHODS: The expression of PDECGF in bladder carcinoma and normal bladder tissue was examined by high performance liquid chromatography and enzyme-linked immunoadsorbent assay. RESULTS: The level of PDECGF expression was fourfold higher in bladder carcinoma compared with normal bladder tissue. The expression of PDECGF in invasive bladder carcinoma was fourfold higher than that in superficial carcinomas. In addition, the expression of PDECGF in T1 bladder carcinoma was twofold higher than that in Ta carcinomas. PDECGF expression level correlated with a higher grade of bladder carcinoma. Patients with Ta bladder carcinoma with low PDECGF expression had a longer postoperative tumor free period than those with high expression in the 3-year follow-up. CONCLUSIONS: The current study demonstrated that the level of PDECGF expression correlated with both stage progression and a higher grade of bladder carcinoma, and that elevated PDECGF expression predicted early recurrence in Ta bladder carcinoma. These results suggest that elevated PDECGF expression might be associated with a greater possibility of recurrence and disease progression.

Adult↗

HLA-DRB1*0101 and *0405 as protective alleles in Japanese patients with renal cell carcinoma.

A variety of malignancies have been linked to major histocompatibility complex genes, including the DRB1 alleles. The association of certain DRB1 antigens with renal cell carcinoma (RCC) has been both claimed and disclaimed. To determine whether HLA-DRB1 genotypes are associated with RCC, we used the modified PCR-RFLP method for the high-resolution HLA-DRB1 genotyping of 96 Japanese RCC patients. There were no significantly frequent HLA-DRB1 alleles, whereas the DRB1*0101 and *0405 alleles had significantly lower frequencies [P = 0.004, relative risk (RR) = 0.2 and P = 0.002, RR = 0.4) in the RCC patients than in the healthy Japanese controls (n = 1216). Moreover, patients with the HLA-DRB1 *0101 or *0405 allele tended to be in earlier stages and to have less aggressive tumors than patients with neither of these alleles. The corresponding serotyping subclassification, however, showed a significantly lower frequency only for DRB1-DR1 (P = 0.01, RR = 0.3). High-resolution genotyping is essential because the polymorphism of the peptide-binding domain of major histocompatibility complex class II molecules is more precisely determined by genotypes than serotypes. In addition, inherent technical difficulties and potential typing errors render serotyping inefficient. Our data suggest that HLA-DRB1*0101 and *0405 are protective alleles for both RCC development and tumor progression.

Adult↗

Membrane type 1 matrix metalloproteinase digests interstitial collagens and other extracellular matrix macromolecules.

Membrane type 1 matrix metalloproteinase (MT1-MMP) is expressed on cancer cell membranes and activates the zymogen of MMP-2 (gelatinase A). We have recently isolated MT1-MMP complexed with tissue inhibitor of metalloproteinases 2 (TIMP-2) and demonstrated that MT1-MMP exhibits gelatinolytic activity by gelatin zymography (Imai, K., Ohuchi, E., Aoki, T., Nomura, H., Fujii, Y., Sato, H., Seiki, M., and Okada, Y. (1996) Cancer Res. 56, 2707-2710). In the present study, we have further purified to homogeneity a deletion mutant of MT1-MMP lacking the transmembrane domain (DeltaMT1) and native MT1-MMP secreted from a human breast carcinoma cell line (MDA-MB-231 cells) and examined their substrate specificities. Both proteinases are active, without any treatment for activation, and digest type I (guinea pig), II (bovine), and III (human) collagens into characteristic 3/4 and 1/4 fragments. The cleavage sites of type I collagen are the Gly775-Ile776 bond for alpha1(I) chains and the Gly775-Leu776 and Gly781-Ile782 bonds for alpha2(I) chains. DeltaMT1 hydrolyzes type I collagen 6.5- or 4-fold more preferentially than type II or III collagen, whereas MMP-1 (tissue collagenase) digests type III collagen more efficiently than the other two collagens. Quantitative analyses of the activity of DeltaMT1 and MMP-1 indicate that DeltaMT1 is 5-7.1-fold less efficient at cleaving type I collagen. On the other hand, gelatinolytic activity of DeltaMT1 is 8-fold higher than that of MMP-1. DeltaMT1 also digests cartilage proteoglycan, fibronectin, vitronectin and laminin-1 as well as alpha1-proteinase inhibitor and alpha2-macroglobulin. The activity of DeltaMT1 on type I collagen is synergistically increased with co-incubation with MMP-2. These results indicate that MT1-MMP is an extracellular matrix-degrading enzyme sharing the substrate specificity with interstitial collagenases, and suggest that MT1-MMP plays a dual role in pathophysiological digestion of extracellular matrix through direct cleavage of the substrates and activation of proMMP-2.

Collagen↗

L-arginine ameliorates recirculation and metabolic derangement in brain ischemia in hypertensive rats.

The effects of L-arginine (a precursor of nitric oxide, NO) on cerebral blood flow (CBF), cerebrovascular resistance (CVR) and metabolites in the ischemic brain were examined in spontaneously hypertensive rats with bilateral carotid artery occlusion for 30 min followed by 60 min-recirculation. The administration of L-arginine (300 mg/kg, i.v.) increased the CBF by an average of 11 ml x 100 g-1 x min-1 (P < 0.05 vs. at rest), and N(omega)-nitro-L-arginine (L-NNA, an inhibitor of NO synthase, 5 mg/kg, i.v.) reduced the CBF by 5-6 ml x 100 g-1.min-1 with increase in the mean arterial pressure by 26 mmHg. During ischemia the CBF significantly decreased to below 8% of the resting values in all rats. The largest blood flow in postischemic hyperemia was 171 +/- 9% of the resting CBF in the rats with L-arginine (P < 0.05 vs. L-NNA and saline), followed by 126 +/- 5 with saline and 109 +/- 3 with L-NNA. The CVR at 60 min of recirculation was 3.291 +/- 0.144 mmHg . ml-1. 100 g-1 .min-1 in the rats with saline, remained low level of 2.711 +/- 0.124 with L-arginine (P < 0.01 vs. L-NNA and P < 0.05 vs. saline) and in contrast, significantly increased to 5.732 +/- 0.184 with L-NNA (P < 0.01 vs. L-arginine and saline, respectively). Tissue lactate with saline increased 2.3-fold at 60 min of recirculation, whereas the increase was inhibited to 1.4-fold after L-arginine treatment (P < 0.01 vs. L-NNA) and in contrast, significantly increased 5.7-fold with L-NNA. The ATP and glucose levels were better preserved in the rats with L-arginine than in those with L-NNA or saline. These findings support that the enhanced postischemic hyperemia is beneficial to the ischemic brain and the administration of L-arginine may be potentially useful for the treatment of acute stroke.

Animals↗

Enhancement of cartilage matrix protein synthesis in arthritic cartilage.

OBJECTIVE: To investigate whether the synthesis of cartilage matrix protein (CMP) is enhanced in arthritic cartilage. METHODS: The content of CMP in human and pig cartilage was determined by immunoblotting, and CMP-producing chondrocytes in osteoarthritic (OA) and rheumatoid arthritic (RA) joints were immunostained. RESULTS: CMP was undetectable in the condylar cartilage and disc of pigs, whereas it was abundant in the rib and tracheal cartilage of the same animals. By immunohistochemical analysis, CMP was localized in only a few chondrocytes (5%) in normal human joints, whereas numerous chondrocytes (>60%) were immunostained in RA joints. The number of CMP-producing cells was also increased in OA cartilage (>40%). Immunoblotting analyses confirmed that the CMP content in the cartilage from OA and RA patients was much higher than that in normal cartilage. CONCLUSION: These findings demonstrate that articular chondrocytes can synthesize CMP, although it is suppressed under physiologic conditions. The results also suggest that articular chondrocytes express CMP in response to arthritic stimuli.

Adult↗

Deposition of extracellular matrix on silicone intraocular lens implants in rabbits.

PURPOSE: To examine the deposition of extracellular matrix on silicone intraocular lenses (IOLs) implanted experimentally into rabbit eyes by electron microscopy and to determine the immunolocalization of extracellular matrix components, including collagen types and cellular fibronectin, on these IOLs. METHODS: We performed phacoemulsification and aspiration of the crystalline lens and implanted a foldable silicone IOL in the capsular bag of one eye of each of 26 adult albino rabbits under general anesthesia. After 8 weeks the animals were killed and the eyes were enucleated. The silicone IOLs were processed for electron microscopy and for immunohistochemical detection of collagen types I, III, and IV and cellular fibronectin. RESULTS: Electron microscopy revealed deposition of a presumed cell matrix complex on the optic portion of all silicone IOLs, as well as the adhesion of presumed macrophages and foreign-body giant cells. Cellular deposits showed immunoreactivity for cellular fibronectin. Fibrous or membranous deposits exhibited immunoreactivity for cellular fibronectin and collagen types I and III. A few type IV collagen-immunoreactive deposits were also seen. CONCLUSION: Deposits of extracellular matrix components were observed on silicone IOLs. These deposits may form the scaffolding for the adhesion and proliferation of cells. These matrix components appeared to be the products of cells adhering to the surfaces of IOLs, including lens epithelial cells, macrophages and foreign-body giant cells, indicating that the process of granulation was incomplete.

Animals↗

Differential effects of the serotonin receptors on cultured rat cerebral cortical neurons.

Effects of serotonin (5-HT) on cerebral cortical neurons were examined by patch clamp techniques. 5-HT produced a variety of responses such as outward (19/73 patches/neurons), slow inward (15/73 patches/neurons), fast inward (8/73 patches/neurons), and mixed currents (initially fast inward deflection followed by an outward response: 2.73 patches/neurons), with a latency of 12 sec, 15 sec, 0 sec, and 0 sec respectively, at a holding potential of -60 mV in whole-cell patches. The fast inward currents were again evoked by a selective 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide hydrochloride (CPBG). In the cell-attached patch clamp configuration, 5-HT inside the patch pipette elicited single channel currents with slope conductances of 42 pS and 132 pS (4/42 patches/neurons). CPBG inside the patch pipette evoked inward single channel currents with a lower slope conductance of 41 pS (3/23 patches/neurons). In contrast, application of 5-HT or a 5-HT2 receptor agonist, alpha-methyl-5-hydroxytryptamine-maleate, outside the patch pipette induced outward single channel currents with a major slope conductance of 140 pS (8/30 patches/neurons) or 135 pS (6/20 patches neurons), respectively. These results indicate that the outward and fast inward currents may be mediated respectively by the 5-HT2 receptor, which is coupled to a G-protein, and by the 5-HT3 receptor, which contains the non-selective cation channel, and that the mixed type may be caused by both the 5-HT2 and 5-HT3 receptors.

Animals↗

Volumetric quantification of brain development using MRI.

We devised a three-dimensional method for estimation of cerebral development and myelination which measures cerebral volume using MRI. Accuracy of the system was estimated using cadaver brains. The mean percentage error in the calculated volumes compared with the real volumes was 2.33%, range 0.00-5.33%. We applied the method to the volume of both cerebral hemispheres (CH), basal ganglia, thalamus and internal capsule (BT), and myelinated white matter (WM) in 44 neurologically normal individuals (4 months to 28 years of age), 13 patients with spastic motor disturbances (2-25 years of age), and 9 patients with athetotic motor disturbances (2-23 years of age). In the neurologically normal cases, the volumes of CH, BT and WM increased with age; the volume of MW more slowly than that of CH. In cases with spastic motor disturbances, the volumes of CH, BT and WM were between -1.4 and 3.5 SD, -1.0 and -3.5 SD, and 0.0 and -5.2 SD respectively, of those of neurologically-normal cases. On the other hand, 7 of the 9 cases with athetotic motor disturbances were within 2 SD of the volume of CH in neurologically normal cases. Our method for direct measurement of cerebral volume based on serial MRI should be useful for the accurate assessment of brain development and quantitative analysis of delayed myelination.

Adolescent↗

Diffusive sampling and biological monitoring of 2-bromopropane.

The possibilities to apply personal ambient air monitoring by diffusive sampling and biological exposure monitoring by urinalysis for 2-bromopropane or its metabolites were explored. The abilities of carbon cloth to adsorb 2-bromopropane was examined by experimental vapor exposure followed by solvent extraction and FID-GC. Urine from factory workers and rats exposed to 2-bromopropane were analyzed for 2-bromopropane, acetone and isopropyl alcohol by FID-GC, and for bromide ion by ECD-GC after chemical methylation. Carbon cloth adsorbed 2-bromopropane in a manner linearly related to exposures up to 1500 mg/m3 and to 8 h. The adsorption could quantitatively detect a 15 min peak exposure at 3,000 mg/m3. In rat experiments, analyses of urine samples collected over a 4-h period after termination of a 4-h exposure to 2-bromopropane at 500, 1,000 or 1,500 mg/m3 showed that acetone and bromide ion were excreted dose-dependently. Essentially, no 2-bromopropane or isopropyl alcohol was detected. When the analytical methods were applied to urine samples from 5 male workers exposed to 2-bromopropane at a low level (3 mg/m3 as a geometric mean), acetone and bromide ion levels were within respective normal ranges in four cases, but were higher than the upper limits of the normal ranges in the fifth case of a foreman who probably had the highest exposure. Thus, diffusive sampling is applicable to monitor exposure to 2-bromopropane. Urinalysis for acetone and bromide ion in combination appears to be a promising selective tool for biological monitoring of occupational exposure to 2-bromopropane.

Air Pollutants↗

Monitoring of occupational exposure to 1-butanol by diffusive sampling and urinalysis.

OBJECTIVES: To investigate the possibility of applying diffusive air sampling and urinalysis (for mother compound and metabolites) to the monitoring of exposure of factory workers to 1-butanol. METHODS: The performance of carbon cloth in adsorbing 1-butanol vapor in air was studied by experimental exposure of the cloth to 1-butanol at 50, 100, 200 or 400 ppm for up to 10 h. 1-Butanol in the exposed cloth was extracted with carbon disulfide and this was followed by gas-chromatographic (GC) analysis. Urine samples were collected from factory workers occupationally exposed to 1-butanol and from rats exposed experimentally to 1-butanol vapour (up to 200 ppm). The urine samples were analyzed by GC without any pretreatment, or after treatment with hydrochloric acid or hydrolase preparation. RESULTS: The performance of the carbon cloth was such that it adsorbed 1-butanol in proportion to the concentration (up to 400 ppm) and the duration (up to 10 h) of exposure, and responded quantitatively to a 15-min exposure up to 400 ppm. The amount of 1-butanol (after enzymic or acid hydrolysis) in post-exposure urine samples from rats was proportional to the exposure intensity. The proportion of free 1-butanol in total 1-butanol (i.e., free+conjugated) in urine was higher after 100 or 200 ppm exposure (35-40%) than after 50 ppm exposure (about 8%). There was a significant increase in total 1-butanol concentration (but not in free 1-butanol) in shift-end urine samples of workers exposed to 1-butanol at concentrations up to 3 ppm. CONCLUSIONS: Diffusive sampling with carbon cloth as an adsorbent can be applied to ambient air monitoring of exposure to 1-butanol. Urinalysis for 1-butanol after hydrolysis is sensitive enough to detect occupational 1-butanol vapour exposure at 3 ppm.

1-Butanol↗