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Biomedical subjects

Y Iwata

Publications and source records attributed to Y Iwata.

At least 109 records · Page 6Linked to original sources
PubMed1996

Expression of a dystrophin-sarcoglycan complex in serum-deprived BC3H1 cells and involvement of alpha-sarcoglycan in substrate attachment.

Dystrophin and alpha- and gamma-sarcoglycans were newly expressed in BC3H1 cells during differentiation induced by serum withdrawal. These proteins formed a tight complex with other dystophin-associated proteins (DAPs), as detected by immunoprecipitation with anti-dystrophin antibody. Integrins beta 1 and beta 3, vinculin, and focal adhesion kinase were also detected in the same immunoprecipitate. In a cell adhesion assay, differentiated BC3H1 cells attached more efficiently to type I collagen-coated dishes than nondifferentiated cells and loss of alpha-sarcoglycan induced by antisense ODN in differentiated cells resulted in significant inhibition of cell adhesion. Thus dystrophin and DAPs, at least partly, form a complex with the focal adhesion proteins in differentiated BC3H1 cells and alpha-sarcoglycan seems to modulate the function of the focal adhesion complex in these cells.

Animals↗
PubMed1996

The effects of N-methyl-D-aspartate (NMDA) and its competitive antagonist, 3-(2-carboxypiperazine-4-yl)propyl-1-phosphonic acid (CPP), injected into caudate-putamen on kindled amygdaloid seizures in rats.

N-methyl-D-aspartate (NMDA) is an agonist of NMDA receptors and 3-(2-carboxypiperazine-4-yl)propyl-1-phosphonic acid (CPP) is an NMDA receptor antagonist. NMDA (1 or 2 nmol per side) or CPP (2.5 or 10 nmol per side) was injected into the bilateral caudate-putamen of amygdaloid-kindled rats. In addition, CPP (10 nmol) was ipsilaterally or contralaterally injected into the unilateral caudate-putamen. Either 20 min after NMDA or 60 min after CPP, the kindled amygdala was stimulated at the generalized seizure triggering threshold. In a few animals tested, injection of NMDA into the bilateral caudate-putamen produced transient spiking activity, with no clinical manifestations. This feature began about 5 min after the injection and lasted about 10 s. When these animals were excluded from the statistical analysis, NMDA in the caudate-putamen showed a weak and non-significant anticonvulsant action. Injection of CPP into the bilateral caudate-putamen caused no ictal change, but markedly suppressed the kindled seizures. Injection of CPP into the unilateral caudate-putamen, regardless of the site, did not cause any ictal change, or affect the stimulation of the amygdala. These findings suggest that: (1) NMDA receptors in the caudate-putamen facilitate the development of kindled amygdaloid seizures; (2) activation of NMDA receptors in the bilateral, but not in the unilateral, caudate-putamen is required for the generalization and expression of kindled amygdaloid seizures.

Amygdala↗
PubMed1996

Inhibition of mucosal lipid hyperoxidation by green tea extract in 1,2-dimethylhydrazine-induced rat colonic carcinogenesis.

Phosphatidylcholine hydroperoxide (PCOOH) measured using a chemiluminescence detector to examine colonic mucosal lipid hyperoxidation increased after injection of 1,2-dimethylhydrazine and green tea extract (GTE), which we previously showed inhibited carcinogenesis and oxidative DNA damage in the gastrointestinal tract. Therefore, the hyperoxidation of membrane phospholipids reflected well the degree of DNA damage and carcinogenic alteration, and may be a useful intermediate biomarker for initiation of carcinogenesis.

1,2-Dimethylhydrazine↗
PubMed1996

Inhibitory effects and toxicity of green tea polyphenols for gastrointestinal carcinogenesis.

BACKGROUND: Recently, and epidemiologic study showed a lower risk of gastrointestinal carcinogenesis in green tea drinkers. An experiment on two-stage skin carcinogenesis in mice showed that (-)-epigallocatechin gallate (EGCG), one of the main constituents of green tea, inhibited tumor formation. METHODS: The inhibitory effects of EGCG and green tea extract (GTE) on N-ethyl-N'-nitro-N-nitroguanidine (ENNG)-induced duodenal carcinogenesis in the mouse, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced carcinogenesis of the glandular stomach in the rat, and azoxymethane-induced colon carcinogenesis in the rat were examined. The toxicity of GTE was assessed experimentally and GTE was applied clinically in normal volunteers to determine the effective dose and to assess its harmful effects. RESULTS: EGCG and GRE inhibited chemical carcinogenesis of the gastrointestinal tract in rodents. Judging from the epidemiologic and experimental findings, it was determined that 1 g per day of GTE might be an effective dose. GTE was not toxic and no harmful effect was found during its clinical use. CONCLUSIONS: These findings suggest that EGCG and GTE are useful in preventing gastrointestinal carcinogenesis, and the clinical usefulness of GTE, which has no harmful effects and is inexpensive, should be studied further.

Animals↗
PubMed1996

Anticonvulsant action of metabotropic glutamate receptor agonists in kindled amygdala of rats.

1S,3R-1-Aminocyclopentane-1,3-dicarboxylate (1S,3R-ACPD) and L-2-amino-4-phosphonobutyrate (L-AP4) are selective agonists of metabotropic glutamate receptors (mGluRs). 1S,3R-ACPD (200 nmol) injected into the amygdala (AM) of non-kindled rats produced immediate and transient seizures, characterized by immobility, searching, and wet-dog shakes. However, this ictal response was not observed in AM-kindled rats. Intra-AM injection of 1S,3R-ACPD (40 or 200 nmol) or L-AP4 (200 nmol) resulted in a delayed and marked suppression of kindled seizures, 3 days after 40 nmol of 1S,3R-ACPD, 1 day after 200 nmol of 1S,3R-ACPD, and from 1 to 3 days after 200 nmol of L-AP4. These and the previous findings suggest that: (1) the excitatory action of 1S,3R-ACPD in the AM, which may be mediated by the postsynaptic mGluRs, is reduced after completion of kindling; (2) 1S,3R-ACPD and L-AP4 exert anti-convulsant action in the AM, presumably by activating the presynaptic as well as postsynaptic mGluRs.

Aminobutyrates↗
PubMed1996

Dystrophin-glycoprotein complex purified from hamster cardiac muscle. Comparison of the complexes from cardiac and skeletal muscles of hamster and rabbit.

The dystrophin-glycoprotein complex was isolated from hamster ventricular muscle by a method involving homogenization of muscle directly in the presence of 1% digitonin, followed by chromatography on succinylated wheat germ agglutinin agarose, Diethyl aminoethyl (DEAE) cellulose, and/or immunoaffinity agarose. Protein yield of the DEAE cellulose-purified dystrophin-glycoprotein complex was 120 +/- 30 (n = 3) micrograms per 5 g hamster ventricular muscle. The cardiac dystrophin-glycoprotein complex, unlike the skeletal muscle counterpart, could not be solubilized from a microsomal fraction with digitonin or some other detergents. By sodium dodecyl sulfate gel electrophoresis, protein composition of the dystrophin-glycoprotein complexes from hamster cardiac muscle was found to be significantly different from that of rabbit skeletal muscle which has been extensively studied. This difference mainly arises from the species difference, because in hamster the cardiac and skeletal muscle complexes exhibited essentially the same protein composition. In rabbit, on the other hand, there are differences between the cardiac and skeletal complexes in the relative abundance of 60 and 64 kDa proteins and in the apparent M(r) of alpha-dystroglycan. We found that the content of the dystrophin-glycoprotein complex, estimated by quantitative immunoblot assay, is at least 5 times more abundant in cardiac than in skeletal muscle in hamster and rabbit.

Animals↗
PubMed1996

Reconstruction of the 3D coordinates of alpha-carbon atoms of proteins from a pair of stereographic figures.

In an attempt to promptly use the experimentally determined structures of proteins in modeling studies, we have developed the program ReconstC alpha to generate the 3D coordinates of alpha-carbon atoms from a pair of stereographic figures. Calculations of the 3D coordinates were performed by estimating the stereo parameters systematically. Geometrical features of C alpha traces were used to evaluate the integrity of the calculated structure. The program was applied to four kinds of protein structures to examine the performance. It was found that the root-mean-square deviation of atomic positions between constructed and reference crystal structures ranged from 0.36 to 0.78 A. The range represents a reasonable accuracy and its automatic feature suggests that our approach would be expedient for providing initial structures for protein modeling studies.

Crystallography, X-Ray↗
PubMed1996

Hydrophilicity of quinolones is not an exclusive factor for decreased activity in efflux-mediated resistant mutants of Staphylococcus aureus.

The elevated expression of the norA gene is responsible for efflux-mediated resistance to quinolones in Staphylococcus aureus (E.Y.W. Ng, M. Trucksis, and D.C. Hooper, Antimicrob. Agents Chemother. 38:1345-1355, 1994). For S. aureus transformed with a plasmid containing the cloned norA gene, SA113(pTUS20) (H. Yoshida, M. Bogaki, S. Nakamura, K. Ubukata, and M. Konno, J. Bacteriol. 172:6942-6949, 1990), and an overexpressed mutant, SA-1199B (G.W. Kaatz, S.M. Seo, and C.A. Ruble, J. Infect. Dis. 163:1080-1086, 1991), the MICs of norfloxacin increased 16 and 64 times compared with its MICs for the recipient and wild-type strains, SA113 and SA-1199, respectively. MICs of CS-940, however, increased only two and eight times, even though these two fluoroquinolones are similarly hydrophilic (apparent logPs of approximately -1). No good correlation was found, among 15 developed and developing quinolones, between the increment ratio in MICs and hydrophobicity (r = 0.61). Analysis of the quantitative structure-activity relationship among 40 fluoroquinolones revealed that the MIC increment ratio was significantly correlated with the bulkiness of the C-7 substituent and bulkiness and hydrophobicity of the C-8 substituent of fluoroquinolones (r = 0.87) and not with its molecular hydrophobicity (r = 0.47). Cellular accumulation of norfloxacin in SA-1199B was significantly lower than that in SA-1199, and it was increased by addition of carbonyl cyanide m-chlorophenyl hydrazone. On the other hand, accumulations of CS-940 in these strains were nearly identical, and they were not affected by addition of the protonophore.

Anti-Infective Agents↗
PubMed1996

Small-vessel radiography in situ with monochromatic synchrotron radiation.

PURPOSE: To evaluate the usefulness of a radiographic system with monochromatic synchrotron radiation to depict small vessels and peripheral secretory ducts. MATERIALS AND METHODS: Radiography of various organs was tested in 14 anesthetized dogs and pancreatography was performed in an excised human pancreas by using the following system: monochromatic synchrotron radiation with an energy level just above the k absorption edge of iodine as an x-ray source and a high-definition TV system with a high-light-sensitivity image pick-up tube camera coupled with a fluorescent screen as a detector. RESULTS: This system allowed depiction of small vessels (diameter < 50-100 microns) of the heart (penetrating transmural artery), brain (perforating arteries that arise directly in the circle of Willis), and intestinal organs (vasa recta and their submucosal communications) and of small branches (down to the fifth order) of the pancreatic duct. CONCLUSION: The synchrotron radiation system may be useful for evaluating microcirculatory disorders and early-stage malignant tumors in various human organs.

Adult↗
PubMed1996

Distinct distribution of protein disulfide isomerase family proteins in rat tissues.

We investigated the distribution of protein disulfide isomerase (PDI) family proteins PDI, ERp72, and ERp61 in rat tissues and compared their localization by immunohistochemical double staining. The extent of their expression was diverse in different cell types, although they were ubiquitously distributed in a wide variety of cell types. Prominent staining for all three proteins was detected in thyroid follicular epithelia, tracheal mucous gland cells and chondrocytes, and chief cells and mucous neck cells of the stomach. Hepatocytes, neuronal cells in brain and spinal cord, and pancreatic acinar cells were also consistently and uniformly stained, but with low intensity. On the other hand, distinct differences were observed for the expression of the three proteins in plasma cells, pancreatic islet cells, goblet cells, and Paneth's cells of intestines, seminiferous epithelia, and salivary gland ductal epithelia. The similarities and differences in the distribution of the three proteins provide helpful clues to their biological functions.

Amino Acid Sequence↗
PubMed1996

C-Myc and Bcl-2 protein expression during the induction of apoptosis and differentiation in TNF alpha-treated HL-60 cells.

We examined c-Myc and Bcl-2 protein expressions during the induction of apoptosis and differentiation in TNF alpha-treated HL-60 cells using a two-color flow cytometric method. We found that c-Myc protein was rapidly down-regulated in the apoptotic cells while Bcl-2 protein was expressed at relatively high levels. Concomitantly with terminal differentiation Bcl-2 protein was down-regulated in differentiating cells as well as c-Myc protein. We also showed that c-myc antisense oligonucleotides could induce apoptosis in HL-60 cells whereas bcl-2 antisense did not induce apoptosis during the early time of treatment. These results suggest that the down-regulation of c-Myc protein expression is a primary event to induce apoptosis and neither consistent expression of c-Myc protein nor rapid down-regulation of Bcl-2 protein is necessary for the initial processing of apoptosis in HL-60 cells. Furthermore, concomitant down-regulation of c-Myc and Bcl-2 is closely associated with terminal differentiation and apoptotic cell death of HL-60 cells treated with TNF alpha.

Apoptosis↗
PubMed1996

Evaluation of antitumor activities of hyaluronate binding antitumor drugs: synthesis, characterization and antitumor activity.

To enhance the selective delivery of antitumor drugs into regional lymph nodes and cancerous tissues via a hyaluronate (HA) receptor (CD44), we synthesized HA-mitomycin C complex and HA-epirubicin complex. To investigate the specific distribution of HA into regional lymph nodes and to evaluate the HA receptor on lewis lung carcinoma cells, we also synthesized 14C-labelled HA and fluorescent HA (FR-HA). The metabolic studies of 14C-HA and HA-epirubicin complex were performed in rats. The specific distribution of both compounds to the lymph nodes were observed after sc treatment. Internalization mechanisms of HA into carcinoma cells (lewis lung carcinoma) via HA receptor was investigated using fluorescent HA (FR-HA) in vitro. Internalization of FR-HA following binding to the cell surfaces was observed. HA-Mitomycin C (MMC) exhibited potent anti-metastatic effects against lewis lung carcinoma implanted in mice at an extremely low dose (0.01 mg/kg) whereas free MMC had no effects.

Animals↗
PubMed1996

[Particle Induced X-ray Emission (PIXE) for analysis of trace elements in biological materials].

Outline of Particle Induced X-ray Emission (PIXE) and its application to biomedical samples are described. Charged particles from cyclotron or van de Graaff generator bombards analytical samples and semiconductor detector measures energy and intensity of induced characteristic x-ray. Simultaneous determination for 22Na to 92U is possible by PIXE. 100 nA of 3 MeV protons bombards biomedical samples and detection limits for almost all trace essential elements are sub microgram/g. Only 1 mg of biomedical sample is necessary for determination of trace elements and no chemical procedure is necessary for preparation of analytical sample. PIXE is powerful tool for determination of essential elements and applied for diagnosis for several diseases.

Animals↗
PubMed1996

Hepatic embolization through extrahepatic collateral pathways after hepatic arterial embolization for the hepatocellular carcinoma.

Extrahepatic collateral pathways developing after repeated transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC) make therapeutic arterial embolization for recurrent lesions extremely difficult. TAE was performed through the collateral pathways using a sophisticated micro-catheter with good trackability and pushability and a coaxial system. Twenty-three TAEs were undertaken through the collateral pathways in 13 patients with recurrent HCC who had extrahepatic collateral pathways after the previous hepatic arterial TAE. There were 69 extrahepatic collateral pathways, with partially obstructed hepatic arteries. On the average, three feeding arteries were seen in the liver. The main extrahepatic collateral pathways were the inferior phrenic artery and epicholedocal artery, 18 vessels and 29 vessels, respectively, accounting for about 80% of the total collateral pathways. TAEs were successful in all cases and the number of embolized vessels was 2.1 on average. The average time of the first collateral TAE after the initial conventional hepatic arterial TAE was 2.3 years. Excellent prognosis was observed with a one-year survival rate of 77% and 3-year survival rate of 38% after the collateral TAE. We consider that collateral TAE for recurrent HCC with obstruction of the hepatic artery is the procedure of choice, is technically feasible, and provides better prognosis for the patients.

Adult↗
PubMed1995

Liposome-entrapped phenytoin locally suppresses amygdaloid epileptogenic focus created by db-cAMP/EDTA in rats.

Status epilepticus was induced in rats by injecting a combination of dibutyryl-cAMP (db-cAMP) and ethylenediaminetetraacetic acid (EDTA) into the amygdala (AM), and the effect of phenytoin (PHT), entrapped in liposomes (PHT-L) and given intravenously at 40 mg/kg, on the spiking activity of the AM epileptogenic focus was examined. Electroencephalograms were recorded from the db-cAMP/EDTA-injected AM and the bilateral sensorimotor cortices. One dose of PHT-L, given 30 min after intra-AM db-cAMP, produced immediate and transient seizure suppression, but did not suppress the sequential spiking activity, which lasted for more than 5 h. In contrast, two doses of PHT-L, given 30 and 60 min after intra-AM db-cAMP/EDTA, produced delayed and local suppression of AM discharges, and immediate and transient seizure suppression was also observed. The AM discharges began to be suppressed about 100 min after the second injection of PHT-L injection, with no overt change occurring in cortical spiking activity. This was followed by total seizure suppression about 170 min after the second PHT-L injection. This effect was not observed after one or two injections of PHT alone. When horseradish peroxidase (HRP), to which the blood-brain barrier is impermeable, was entrapped in liposomes (HRP-L) and given intravenously 30 min after intra-AM db-cAMP/EDTA, an accumulation of HRP was found in the db-cAMP/EDTA-injected AM in 2 of the 5 animals tested. With 2 doses of HRP-L given 30 and 60 min after intra-AM db-cAMP/EDTA, the local augmentation of HRP in the AM was found in all 5 of the 5 animals tested. Our findings suggest that: (1) the AM epileptogenic focus created by db-cAMP/EDTA has a high affinity for liposomes, and this factor participates in the local suppression of AM discharges by PHT-L, and (2) two injections of PHT-L are required for the AM to gather an effective amount of PHT-L.

Amygdala↗
PubMed1995

[A case of pulmonary hyalinizing granuloma with its occupational history of dust exposure].

Multiple pulmonary nodules were found in a patient who had an occupational history of coal mining for eleven years and road construction for fifteen years. An open lung biopsy was performed, because nodules had increased in size compared to previous ones and a trasbronchial biopsy was not diagnostic. The nodules were composed of dense concentric lamellar collagenous structures with a serpentine pattern surrounded by an infiltration of histiocytes, lymphocytes and plasma cells with Russel bodies. These findings are compatible with pulmonary hyalinizing granuloma (PHG) named by Liebow A. A. The etiopathogenetic mechanism and the difference between PHG and silicotic nodule is discussed.

Aged↗
PubMed1995

Pulmonary oncocytoma: report of a case in conjunction with an immunohistochemical and ultrastructural study.

An intra-pulmonary mass in a 51 year old Japanese woman was incidentally discovered in the right middle lobe. The resected tumor was grossly well-demarcated, solid, light yellowish white in color and measured 3.0 x 2.0 x 1.5 cm in size. It was composed of a diffuse proliferation of large polygonal cells with an abundant, granular cytoplasm, and round to irregular nuclei with prominent nucleoli. Smaller eosinophilic cells with hyperchromatic nuclei and larger vacuolated cells were also observed. However, no mucin production was detected. There were neither argyrophilic nor argentaffin cells, and no serotonin-positive cells. They showed an immunoreactivity to cytokeratin and vimentin but not to alpha-actin. On electron microscopy, abundant microvilli, which have never been previously described in pulmonary oncocytomas, were observed. Occasional desmosomes and myelin figures as well as numerous mitochondria were also seen. No neurosecretory granules were present. These findings suggested that this tumor might have an epithelial origin from the bronchial serous gland with subsequent cellular degeneration.

Adenoma, Oxyphilic↗