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Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 307 records · Page 17Linked to original sources
PubMed1998

Response of quiescent and total tumor cells in solid tumors to neutrons with various cadmium ratios.

PURPOSE: Response of quiescent (Q) and total tumor cells in solid tumors to neutron irradiation with three different cadmium (Cd) ratios was examined. The role of Q cells in tumor control was also discussed. METHODS AND MATERIALS: C3H/He mice bearing SCC VII tumors received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days using implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty minutes after intraperitoneal injection of sodium borocaptate-10B (BSH), or 3 h after oral administration of dl-p-boronophenylalanine-10B (BPA), the tumors were irradiated with neutrons, or those without 10B-compounds were irradiated with gamma rays. This neutron irradiation was performed using neutrons with three different cadmium (Cd) ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (a cytokinesis-blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in total (P + Q) tumor cells was determined from tumors that were not pretreated with BrdU. The sensitivity to neutrons was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). RESULTS: Without 10B-compounds, the MN frequency in Q cells was lower than that in the total cell population. The sensitivity difference between total and Q cells was reduced by neutron irradiation. Relative biological effectiveness (RBE) of neutrons compared with gamma rays was larger in Q cells than in total cells, and the RBE values for low-Cd-ratio neutrons tended to be larger than those for high-Cd-ratio neutrons. With 10B-compounds, MN frequency for each cell population was increased, especially for total cells. This increase in MN frequency was marked when high-Cd-ratio neutrons were used. BPA increased the MN frequency for total tumor cells more than BSH. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that in BSH-treated Q cells. This tendency was clearly observed in high-Cd-ratio neutrons. CONCLUSION: From the viewpoint of enhancing the Q-cell sensitivity, tumors should be irradiated with high-Cd-ratio neutrons after BSH administration. However, normal tissue reaction remains to be examined because of its low tumor-to-normal tissue and tumor-to-blood biodistribution ratios.

Animals↗
PubMed1998

Cytokine gene expression after myocardial infarction in rat hearts: possible implication in left ventricular remodeling.

BACKGROUND: A large transmural myocardial infarction may initiate structural and geometric changes in the left ventricle that are commonly referred to as remodeling. Progressive, adverse remodeling of the myocardium may lead to ventricular dilatation and congestive heart failure. Recent studies have highlighted the effects of some cytokines on immune-mediated myocyte injury, postischemic myocardial inflammation, and cardiac function. However, studies of the involvement of cytokines in remodeling of the heart are few. METHODS AND RESULTS: In a rat model of myocardial infarction, progressive dilatation of the left ventricular cavity and lack of appropriate hypertrophy of the surviving myocardium were confirmed by transthoracic echocardiography. The relative expression of mRNA for tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 in the infarcted and noninfarcted myocardium of these rats, as well as in a group of sham-operated animals, was assessed by the technique of quantitative polymerase chain reaction amplification. In the infarcted region, TNF-alpha, IL-1beta, and IL-6 gene expression peaked at 1 week after infarction and decreased rapidly thereafter. In contrast, at 20 weeks after infarction, the gene expression levels of these cytokines remained significantly higher in the noninfarcted than in the infarcted zone or in the myocardium of sham-operated animals. Furthermore, the levels of these cytokines in the noninfarcted region correlated with the left ventricular end-diastolic diameter measured at 8 and 20 weeks after infarction. Among these cytokines, IL-1beta expression was highest, and its level correlated well with collagen deposition in the noninfarcted myocardium at 8 and 20 weeks after surgery. At 20 weeks after infarction, immunohistochemical analysis revealed the presence of IL-1beta in macrophages, endothelial cells, and vascular smooth muscle cells in the noninfarcted region, whereas no such immunoreactivity was found in the myocardium of sham-operated animals. CONCLUSIONS: These findings suggest the possible involvement of cytokines during the remodeling process of the noninfarcted left ventricular myocardium.

Animals↗
PubMed1998

Morphological analysis of the early stages of oligodendrocyte development in the vertebrate central nervous system.

Oligodendrocytes are responsible for myelin formation in the vertebrate central nervous system. While in vitro analysis have provided critical information on the cellular properties of oligodendrocyte precursors, they provide limited information on the morphological development of these cells in the intact CNS. Recent studies have begun to provide insights into when and where oligodendrocyte precursors arise in the neural tube. In the chick CNS, the monoclonal antibody O4 selectively labels oligodendrocyte lineage cells both in vitro and in vivo and here we discuss the characteristics of O4+ oligodendrocyte precursors during development of the chick CNS. The earliest oligodendrocytes initially develop in restricted locations in the CNS. In the spinal cord, for example, oligodendrocyte precursors arise in the ventral ventricular zone dorsal to the floor plate. These early oligodendrocyte precursors are integral components of the lining of the central canal and have an embryonic neuroepithelial cell morphology, suggesting that commitment to the oligodendrocyte lineage occurs in the ventricular zone. With maturation these early oligodendrocyte precursors lose their ventricular connection, adopt a uni- or-bipolar morphology, and migrate throughout the CNS. When these cells reach presumptive white matter, they stop migrating, become multiprocessed, and differentiate into immature oligodendrocytes. The maturation of these newly formed oligodendrocytes results in the upregulation of expression of a variety of myelin specific genes such as MBP and PLP and the subsequent elaboration of the myelin organelle. In the developing optic nerve, the onset of myelination occurs several days after oligodendrocyte precursors populate the nerve, suggesting that additional signals are required to induce myelin formation.

Animals↗
PubMed1998

Molecular basis of bovine red-cell protein 4.2 polymorphism in Japanese black cattle.

Cattle were divided into three groups according to the red cell-protein 4.2 (P4.2) phenotypes P4.2(76), P4.2(75) and P4. 2(76/75), whose red cells contained Mr 76000 (P4.2/76), 75000 (P4. 2/75) and both 76000 and 75000 isoforms respectively. To elucidate the molecular basis that underlies the diversity of P4.2, the gene structures of bovine P4.2/76 and P4.2/75 were investigated. Two P4.2 cDNA clones were isolated from bone-marrow cDNAs of the animal with the P4.2(76/75) phenotype. These were identical in size (2.2 kb), encoding major erythroid P4.2 with 687 amino acids, but were different in three nucleotides, resulting in changes of amino acids at the 599th, 601st and 627th residues. Analysis of genomic DNA from the three phenotypes demonstrated that these two clones were derived from gene transcripts by which P4.2/76 and/or P4.2/75 were produced. In vitro transcription and translation of P4.2/76 and P4.2/75 cDNAs indeed generated P4.2/76 and P4.2/75 identical in size to the red-cell proteins. These findings demonstrated that polymorphism of the P4.2 gene at codons 599, 601 and 627 of P4.2 cDNA was the cause of the molecular diversity of bovine red-cell P4.2. Although distinct electrophoretic mobilities suggested a structural difference in the two isoforms, this polymorphism appeared to have little effect at least on P4.2 association with band 3, since no significant difference was observed in the amount of P4.2 relative to total membrane proteins despite the phenotype difference for P4.2.

Amino Acid Sequence↗
PubMed1998

Hyperthermia enhances thermal-neutron-induced cell death of human glioblastoma cell lines at low concentrations of 10B.

PURPOSE: To examine the ability of pre- vs. post-irradiation hyperthermia to enhance the effectiveness of thermal neutrons to kill human glioblastoma cells. METHODS AND MATERIALS: Human glioblastoma cell lines, T98G, A7, A172, and U 87MG, were exposed to thermal neutrons from the Kyoto University Research (KUR) reactor or to 60Co gamma-rays. Hyperthermia was tested before and after irradiation of T98G (44 degrees C, 15 min) and A7 cells (44 degrees C, 40 min), and with different concentrations (0-30 ppm) of 10B-boric acid. The biological end point of all experiments was cell survival measured by a colony formation assay. RESULTS: The relative biological effectiveness (RBE) values of thermal neutrons for these cell lines compared with 60Co gamma-rays were 1.8-2.0 at their D(0) values. When T98G and A7 cells were heated after thermal neutron irradiation, there was a synergistic effect at low 10B concentrations (up to 5 ppm for T98G and up to 10 ppm for A7 cells). With high concentrations of boron (10-30 ppm for T98G and 20-30 ppm for A7 cells), hyperthermia and neutron irradiation interact additively rather than synergistically. There was no enhancement when cells were heated before thermal neutron irradiation. These results suggest that the radiosensitizing effect of hyperthermia may be attributed to partial inhibition of the repair of the potentially lethal damage caused by neutron irradiation.

Boron↗
PubMed1998

Four conductance levels of cloned cardiac L-type Ca2+ channel alpha1 and alpha1/beta subunits.

Formation of single channel subconductance is one of the unique characteristics of the L-type Ca2+ channel. Although alpha1 subunit exhibits a primary function of the channel, it remains uncertain whether alpha1 subunit alone is able to produce subconductance. We tested this by studying single channel currents of cloned cardiac alpha1 subunit expressed in Chinese hamster fibroblast cells, with/without coexpression of cardiac beta subunit. The alpha1 subunit exhibited four distinct levels of conductance (22.7, 14.3, 6.2 and 3.2 pS). Coexpression of beta subunit significantly increased the number of openings in all four levels of conductance without changing the conductance values.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Immediate increase in circulating hepatocyte growth factor/scatter factor by heparin.

Circulating levels of hepatocyte growth factor (HGF)/scatter factor have been recently found to be increased in the early phase of myocardial infarction, and it has been hypothesized that HGF plays a role in angiogenesis and collateral vessel growth. Heparin has also been shown to enhance angiogenesis and to improve collateral blood flow. This study was designed to study the effect of heparin on the release of HGF. In an experimental study, heparin was given to rats intravenously and plasma was collected for measurements of HGF by enzyme-linked immunosorbent assay. A dose-dependent increase in circulating HGF was measured with peak levels occurring 10 min after injection of 300 units/kg of heparin (15.4+/-2.0 ng/ml after v 0. 17+/-0.14 ng/ml before injection,P<0.0001). In a subsequent clinical study, 12 patients received 3000 units of heparin during cardiac catheterization. Circulating HGF increased steeply within 3 min of the injection. Comparable changes in plasma concentrations were measured in samples obtained from femoral vein (8.7+/-3.5 after v 0. 33+/-0.07 before injection P<0.05) or artery (10.5+/-3.2 ng/mlv 0. 27+/-0.05 P<0.01), pulmonary artery (9.1+/-2.0 ng/mlv 0.36+/-0.06 ng/ml,P=0.07 ) or right atrium (8.5+/-1.6 ng/mlv 0.42+/-0.11,P<0.01). This study suggests that heparin-induced effects such as the promotion of angiogenesis may be at least partly due to the release of HGF.

Angina Pectoris↗
PubMed1998

A serological survey of human coronavirus in pigs of the Tohoku District of Japan.

A total of 2496 swine sera from 60 farms in the Tohoku District of Japan was examined for hemagglutination inhibiting (HI) antibodies to human coronavirus (HCV), swine hemagglutinating encephalomyelitis virus (HEV) and bovine coronavirus (BCV). HI antibodies to HCV OC43 strain and HEV 67N strain were highly prevalent with positivity rates of 91.4 and 82.1%, respectively, while the BCV Kakegawa strain was 44.2% positive. Farm D in Miyagi Prefecture showed the highest antibody titers to HCV OC43 strain with geometric mean titers (GMT) of 1:200. These results suggest that pigs might be infected with HCV or an antigenetically related virus as well as HEV.

Animals↗
PubMed1998

Defatted, gas-sterilised cortical bone allograft for posterior lumbar interbody vertebral fusion.

In posterior lumbar interbody vertebral fusion operations, variously sized, rectangular shaped, defatted, freeze-dried, gas-sterilised cortical bone allografts were used in combination with cancellous bone autografts from excised posterior elements. Single-level fusion, with or without internal fixation, was undertaken in 38 patients aged 50 years or less with disc herniation or a failed discectomy (the younger group) and in 33 women aged 60 years or more with degenerative spondylolisthesis (the older group). Of the various observable indicators of union, changes in the allograft-host interface alone proved to be of practical use. The incidence of nonunion in patients managed with pedicle screws, with a hook and rod system or without internal fixation was 0 of 8 patients; 1 of 14 patients; and 3 of 16 patients, respectively, in the younger group, and 0 of 11 patients; 0 of 8 patients; and 2 of 14 patients, respectively, in the older group. Of the six patients with nonunion, three had persistent low back pain and only two had mobility of the fused segment which was evident on lateral radiographs during flexion and extension. No patient had graft collapse. The decrease in the height of the intervertebral space, chiefly due to settlement of the allograft into the vertebral bodies, in the younger and older groups averaged 1.1 and 1.6 mm, respectively. We concluded that this simplified technique is mechanically sound and effective in maintaining the height of the intervertebral space. Even when the graft failed to unite, fibrous union could be obtained without graft collapse. Combination with a simple internal fixator, such as a compression rod, facilitates bone union.

Adult↗
PubMed1998

Does potassium ion concentration affect lung preservation?

To evaluate the influence of potassium ion concentration in an organ preservation solution on lung preservation, four types of solutions were produced. These preservation solutions consisted of sodium and potassium ions on the cation and phosphate ions on the anion with glucose. Contents of solutions were: (1) 155 mmol/l Na+, 0 mmol/l K+; (2) 150 mmol/l Na+, 5 mmol/l K+; (3) 20 mmol/l Na+, 135 mmol/l K+; and (4) 0 mmol/l Na+, 155 mmol/l K+. All four solutions possessed the same osmolarity, the same pH in the same temperature, and the same buffer action. Lungs were preserved at 7 degrees C in these solutions for 24 h and evaluated in a rat lung perfusion system with perfluorochemical emulsion. Pressure-limited perfusions with pressure-limited ventilation were carried out for 20 min before and after preservation. Thereafter, the recovery ratios of pulmonary arterial flow (Q), tidal volume (VT), oxygen tension of the pulmonary venous effluent (PPVO2), and wet-to-dry ratios were compared. The recovery ratios of Q were better in low, but not zero, potassium solutions, whereas wet-to-dry ratios were kept lower in high potassium solutions. No difference in pulmonary compliance or gas exchange was observed against a great change in potassium ion concentration. Therefore, the potassium ion concentration did not play a major role in lung preservation.

Animals↗
PubMed1998

Successful resection of a glomus tumor arising from the lower trachea: report of a case.

Tracheal glomus tumors are extremely rare. We present herein the case of a 43-year-old man with hoarseness who was found to have a glomus tumor arising from the lower trachea. Bronchoscopy and chest computed tomography revealed a polypoid mass in the membranous portion of the trachea just above the carina. The patient underwent successful tracheal sleeve resection and reconstruction. A pathologic diagnosis of a glomus tumor with clear surgical margins was subsequently confirmed, and the patient is well 20 months postoperatively with an intact anastomosis.

Adult↗
PubMed1998

Mitochondrial function in Babesia microti and Babesia rodhaini.

The role of mitochondria in the energy metabolism of Babesia microti and Babesia rodhaini was investigated. A variety of mitochondrial inhibitors showed greater sensitivity to B. microti than to B. rodhaini. Additionally, alpha-glycerophosphate- and succinate-cytochrome c reductase activities in the crude mitochondrial fraction from B. microti were substantially higher than those from B. rodhaini. Our results suggest that the mitochondria of these parasites possess a series of "classical" apparati for energy production and their relative functional role may be quantitatively greater in B. microti when compared with B. rodhaini.

ATP Synthetase Complexes↗
PubMed1998

Mechanism of preservation of myocardial calcium channel function by pyruvate cardioplegic solution.

We evaluated the effects of adding pyruvate to a cardioplegic solution on the preservation of the dihydropyridine-sensitive calcium (Ca2+) current responses to beta-adrenergic stimulation in rabbit cardiac myocytes by measurement of single-channel open probability. Single ventricular myocytes were isolated and stored in St. Thomas' solution with or without pyruvate at 4 degrees C for 2, 6, 12, or 24 hours, and cell-attached single Ca2+ channel currents recordings were made at 20 degrees to 22 degrees C after each storage period. When 0.1 micromol/L isoproterenol (ISO) was applied to the cells, the percent mean open probability of the Ca2+ channels tested in freshly isolated cells was 181% +/- 27% (n = 12) of control values. These responses decreased with an increasing duration of the hypothermic storage and were only 112% +/- 22% (n = 5) of control values after 24 hours of storage in the absence of pyruvate. Conversely, the responses were significantly preserved, to as much as 143% +/- 17% (n = 7), in the presence of 10 mmol/L pyruvate in the storage solution. The application of forskolin to stimulate adenylate cyclase or a membrane-permeable cyclic adenosine monophosphate mimicked the effects of ISO when the myocytes were stored with pyruvate. Pyruvate did not alter the open-channel kinetics or single-channel conductance and lacked any apparent direct effect on the Ca2+ channel activity. We suggest that pyruvate added to the hypothermic storage solution preserves the high-energy phosphates in myocytes that are responsible for Ca2+ channel phosphorylation via beta-adrenergic stimulation. (J Lab

Animals↗
PubMed1998

Alkyl peroxyl radical-scavenging activity of catechins.

Alkyl peroxyl radical (ROO.) generated from the reaction between 20 mM t-butyl hydroperoxide (t-BuOOH) and 200 microM hematin could kill E. coli. The minimum concentrations of catechins sufficient to rescue the bacteria treated with ROO. were found to be 70 microM for (-)-epicatechingallate, 100 microM for (-)-epicatechin and 125 microM for (+)-catechin. These values were comparable with the value of alpha-tocopherol, a typical ROO. scavenger. On the other hand, L-ascorbate and beta-carotene revealed about one tenth the scavenging activity of catechins. No scavenging activity was found for superoxide dismutase even at 86 mM. These facts indicate that catechins have high ROO. scavenging activity.

Catechin↗
PubMed1998

Physical properties of CH61, a newly developed root canal sealer.

This study was performed to evaluate the physical properties (sealing, flow, radio-opacity, working time, and solubility) of a newly developed root canal sealer, CH61. It was compared with Canals, Sealapex, and AH26, which are typical commercially available root canal sealers. The sealing ability was evaluated by dye penetration. The flow was evaluated by two methods. One was flow in the vertical dimension, and the other was disk diameter. Radio-opacity, working time, and solubility were performed in accordance with the standards of the International Organization for Standardization. No dye penetration after immersion for 24 h was noted. In CH61, and there were significant differences between the values for CH61 and Canals, Sealapex, or AH26 (p < 0.001). For flow, the results differed from method to method. The radio-opacity decreased in the following order: AH26, Canals, CH61, and Sealapex. The solubility was the lowest for CH61. This study showed that CH61 had excellent sealing properties and low solubility.

Bismuth↗
PubMed1998

The role of microglia and tumor-primed lymphocytes in the interaction between T lymphocytes and brain endothelial cells.

We investigated the role of IFN-gamma activated microglia in the passage of T lymphocytes across a monolayer of brain endothelial cells (EC) in vitro. Microglia isolated from Fisher 344 (F344) newborn rats were stimulated with IFN-gamma (100 U/ml) for 48 h. T lymphocytes primed with glioma cells were 51Cr-labeled, and added to the monolayer of F344 brain EC. In the adhesion assay, when EC were cultured in medium containing the supernatant of reactive microglia before the assay was carried out, the number of T lymphocytes adhering was increased. In addition, this adhesion was blocked by the addition of anti-ICAM-1 mAb to the EC. In the migration assay, performed using the double chamber system, when reactive microglia adhered to the other side of EC, the number of T lymphocytes migrating to the underwell was also increased. When T lymphocytes were primed to tumor cells in vivo, both their adhesion and migration were enhanced. These results suggest that some soluble factors from reactive microglia are capable of enhancing the expression of ICAM-1 on the brain EC. As a consequence, large numbers of tumor-primed T lymphocytes can adhere to EC and migrate across the EC monolayer.

Animals↗
PubMed1998

Baicalin, an inhibitor of HIV-1 production in vitro.

The flavonoid baicalin markedly inhibits replication of human immunodeficiency virus type 1 (HIV-1) in a concentration-dependent manner in normal peripheral blood mononuclear cells (PBMC) stimulated with phytohemagglutinin (PHA) in vitro. The effect was more pronounced when the cells were pretreated with baicalin. Furthermore, baicalin inhibits HIV-1 replication in PHA-stimulated PBMC from asymptomatic HIV-1-seropositive carriers. The 50% inhibitory concentration for HIV-1 replication was approximately 0.5 microg/ml. At the concentration of 2 microg/ml of baicalin, copy numbers of HIV-1 proviral DNA were approximately 50 times less than in untreated controls. In a cell-free infection system, baicalin inhibited the activity of HIV-1 reverse transcriptase (RT), but not the activity of human DNA polymerases alpha and gamma (DNA polymerase beta was slightly inhibited), suggesting that the anti-HIV-1 effect of baicalin may at least partly be due to inhibition of HIV-1 RT.

Anti-HIV Agents↗