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Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 847 records · Page 47Linked to original sources
PubMed1990

Inhibitory effects of various 2',3'-dideoxynucleoside 5'-triphosphates on the utilization of 2'-deoxynucleoside 5'-triphosphates by terminal deoxynucleotidyltransferase from calf thymus.

Inhibitory effects of four 2',3'-dideoxynucleoside 5'-triphosphates (i.e., those of 2',3'-dideoxyadenosine, 2',3'-dideoxycytidine, 2',3'-dideoxyguanosine and 2',3'-dideoxythymidine, ddATP, ddCTP, ddGTP and ddTTP, respectively) on the utilization of 2'-deoxynucleoside 5'-triphosphates (dNTPs) by terminal deoxynucleotidyltransferase (TdT) from calf thymus were examined in comparison with those of ribonucleoside triphosphates. All four dideoxy compounds strongly inhibited the dNTP utilization by TdT. The inhibitions by these dideoxy compounds were stronger with (dA) than with heat denatured DNA as the primer. Inhibition of TdT by any of these compounds was due to competition with the natural substrate dNTP for the same substrate binding site of the enzyme. Ki values for these dideoxynucleoside triphosphates (ddNTPs) were much lower than the Km values for the corresponding dNTPs indicating a higher affinity of TdT for ddNTP than for dNTP. Among the Ki values determined with (dA) as the primer, those for ddATP (1.3 microM), ddGTP (1.3 microM) and ddCTP (2.8 microM) were lower than that for ddTTP (17.5 microM). With heat-denatured DNA, the Ki for ddATP (2.9 microM) was smaller than those for the other dideoxynucleotides (7.3-35 microM). Also, both the Km for dATP and the Ki for ATP were the lowest among those of the respective deoxynucleotide substrates and ribonucleotide inhibitors. These results indicate that TdT has a stronger affinity for the adenine base of all of the ribo-, deoxyribo-, and dideoxyribo-nucleoside triphosphates than for the other bases of these nucleotides.

Animals↗
PubMed1990

Differential inhibition by an antitumoral drug 10-[gamma-diethylaminopropylamino]-6-methyl-5H-pyrido[3',4': 4,5]pyrrolo [2,3-G]isoquinoline (BD-40), a pyrido-pyrrolo-isoquinoline derivative, of in vitro DNA synthesis catalyzed by various DNA polymerases.

The effects of BD-40, a pyrido-pyrrolo-isoquinoline analogue of ellipticines, and its 2-acetylated derivative (BD-84) and in vitro DNA synthesis catalyzed by purified preparations of various DNA polymerases were examined. The major conclusions are: (1) Both BD-40 and BD-84 strongly inhibit the DNA synthesis by DNA polymerase or reverse transcriptase with poly(rA).oligo(dT) as the template.primer. (2) Both compounds moderately inhibit the DNA synthesis by DNA polymerase alpha or E. coli DNA polymerase I with activated DNA. However, the DNA synthesis by DNA polymerase beta is resistant to inhibition by BD-40 and slightly sensitive to that by BD-84. (3) BD-84 is more inhibitory than BD-40 in DNA syntheses by various DNA polymerases except in those by DNA polymerase alpha and terminal deoxyneuclotidyltransferase to which both compounds are similarly inhibitory. (4) Kinetic analyses revealed that the observed inhibitions are due to competition between the drug or the drug-bound template.primer and the free template.primer for the same binding site of the enzyme.

Animals↗
PubMed1990

IL-6 activity in feline infectious peritonitis.

Involvement of IL-6 in the development of vasculitis and polyclonal gammopathy in feline infectious peritonitis (FIP) was investigated, by using the proliferative responses of two IL-6-dependent murine hybridoma cell clones, B3B1 and MH60.BSF-2 cells. A significant IL-6 activity was found in sera and ascitic fluids of cats with FIP, whereas no IL-6 activity was detected in sera from healthy cats. In these FIP cats, IL-6 activity in ascitic fluids was significantly higher than that in sera. Peritoneal exudate cells from FIP cats were also found to release a high level of IL-6 to the culture supernatant. The ascitic IL-6 activity was eluted into the fractions corresponding to the m.w. of 30,000 to 40,000 in gel filtration, and into the fractions at the salt concentration from 0.2 to 0.3 M NaCl in anion exchange chromatography. The level of ascitic IL-6 activity was inversely correlated to serum albumin/globulin ratio in these FIP cats. These findings indicate that IL-6 accumulated in the ascites might leaked into the systemic circulation, and be linked to systemic alterations such as enhanced synthesis of Ig and acute phase proteins.

Animals↗
PubMed1990

Differential inhibitory effects of some catechin derivatives on the activities of human immunodeficiency virus reverse transcriptase and cellular deoxyribonucleic and ribonucleic acid polymerases.

The two components of Camellia sinensis (tea plant) [i.e., (-)-epicatechin gallate and (-)-epigallocatechin gallate] were found to differentially inhibit the activities of reverse transcriptase and cellular DNA and RNA polymerases. Under the assay conditions optimized for each enzyme species, the strongest inhibition by these compounds was observed with reverse transcriptase. The concentrations of (-)-epicatechin gallate and (-)-epigallocatechin gallate required for 50% inhibition of the activity of human immunodeficiency virus (HIV) reverse transcriptase were in the range of 0.01-0.02 microgram/mL. On the other hand, neither (-)-epicatechin, (-)-epigallocatechin, nor gallic acid, the constituents of (-)-epicatechin gallate and (-)-epigallocatechin gallate, was inhibitory to the activity of HIV reverse transcriptase at concentrations up to 1 microgram/mL. The mode of inhibition of reverse transcriptase and other DNA polymerases by these compounds was competitive with respect to the template-primer, whereas the mode of inhibition of RNA polymerase was competitive with respect to the nucleotide substrate. The Ki values of HIV reverse transcriptase for (-)-epicatechin gallate and (-)-epigallocatechin gallate were determined to be 7.2 and 2.8 nM, respectively, which are smaller by 1-2 orders of magnitude than the Ki's of other DNA and RNA polymerases for these compounds.

Animals↗
PubMed1990

[Clinical results of conventional fractionation radiotherapy for glottic and supraglottic laryngeal cancers--the usefulness of hyperfractionation for these cancers].

Ninety patients with glottic and eighteen patients with supraglottic laryngeal cancer (anyN, M0) were treated by conventional fractionation radiotherapy between July, 1963 and August, 1988. Tumor control and cause specific survival were evaluated according to tumor location (glottic or supraglottic) and tumor size (T1, T2, T3, or T4). As a result, the steepness of dose-response curve for the tumor control in T1-2 glottic and T2 supraglottic tumors was more slanting upwards than that in other laryngeal tumors, and the patients whose tumors were irradiated at larger doses had a tendency to survive longer. These results suggested that T1-2 glottic and T2 supraglottic laryngeal tumors can have a good application for hyperfractionation radiotherapy which is a radiation therapy with multiple fractions per day with a small fraction size and with which tumors can receive larger radiation doses than with conventional fractionation radiotherapy. Five patients with glottic or supraglottic tumors treated by hyperfractionation radiotherapy obtained CR, and now show no recurrence. We are going to investigate the usefulness of hyperfractionation radiotherapy after treating more patients with Twice-A-Day fractionation radiotherapy.

Adult↗
PubMed1990

Acidic phospholipids directly inhibit DNA binding of mammalian DNA topoisomerase I.

Inhibition of mammalian DNA topoisomerase I by phospholipids was investigated using purified enzyme. Acidic phospholipids inhibited the DNA relaxation activity of topoisomerase I whereas neutral phospholipid, phosphatidylethanolamine, did not. Accumulation of a protein-DNA cleavable complex, an intermediate which is known to accumulate upon inhibition by a specific inhibitor camptothecin, did not occur. The filter binding assay revealed that the DNA binding activity of the enzyme was inhibited by acidic phospholipids. Moreover, direct binding of phosphatidylglycerol to topoisomerase I was demonstrated. These results indicated that the inhibitory effect of acidic phospholipids on topoisomerase I was due to the loss of the DNA binding of the enzyme as a result of direct interaction between phospholipids and the enzyme.

Animals↗
PubMed1990

Morphological changes of astroglia in the cerebellar cortex of developing mice after neonatal administration of cytosine arabinoside.

Neonatal administration of cytosine arabinoside (Ara-C) induced marked hypoplasia of the mouse cerebellum. In 17-20-day-old mice with neonatal Ara-C injections, the external granular layer was still preserved as an irregular cell laminae in the superficial part of the cerebellum, in contrast to its complete disappearance in normal animals at these stages. Immunohistochemical examination using anti-glial fibrillary acidic protein and monoclonal antibody-1D11 (Ono et al: Dev. Brain Res., 50:154-159, 1989) demonstrated malformation of a palisade-like arrangement of labeled glial fibers in the superficial part of the Ara-C treated mouse cerebellum. Furthermore, the immunoreactive astroglia were observed just beneath the pial membrane and their processes were oriented to the deeper part of the molecular layer.

Animals↗
PubMed1990

Apatite--wollastonite containing glass ceramic granule-fibrin mixture as a bone graft filler: use with low granular density.

The purpose of this study was to investigate bone formation after implantation of a mixture of apatite--wollastonite containing glass ceramic granules (A-W.GC, 220-355 microns) and fibrin glue with a low A-W.GC granular density. The fibrinogen was prepared from rat blood plasma. A mixture of A-W.GC granules and fibrin glue 1:4 in volume ratio (1:4 mixture) was implanted in the proximal metaphysis of the rat tibia, and bone formation was evaluated quantitatively by histomorphometry in undecalcified specimens. Microangiography was performed in animals sacrificed 5 days after the operation. The results were compared with those of a previous study in which a 1:1 mixture of A-W.GC granules and fibrin glue was used. With the 1:4 mixture, the A-W.GC density was 39.7% because of concentration of fibrin at packing. Good early vascularization comparable to that after implantation of the 1:1 mixture was observed. Bone formation proceeded at the same rate as after implantation of 1:1 mixture, but the level of the plateau was higher than that for the 1:1 mixture. The osteoconductive potential of the 1:4 A-W.GC-fibrin mixture was similar to that of the 1:1 mixture, and was higher than that of A-W.GC without fibrin.

Animals↗
PubMed1990

Mechanical properties of bone after implantation of apatite-wollastonite containing glass ceramic-fibrin mixture.

Mechanical properties of bone implanted with a mixture of apatite-wollastonite containing glass ceramic (A-W.GC) granules and fibrin were examined by compression testing. A 1:1 mixture of A-W.GC granules and fibrin (Group 1), 1:4 mixture of A-W.GC granules and fibrin (Group 2), and 1:1 mixture of hydroxyapatite (HA) granules and fibrin (Group 3) were implanted in the distal femoral metaphyses of rabbits. Histomorphometric analysis suggested that A-W.GC has a greater osteoconductive potential than HA. Trabeculalike structures were observed 24 weeks after the operation in all groups but were most notable in Group 2. Twenty-four weeks after the operation, in Groups 1 and 3, the compressive strength and compressive stiffness were higher than that of normal cancellous bone, and the fracture toughness was comparable with that of normal cancellous bone. In Group 2, all three values were similar to those of normal cancellous bone. Implantation of A-W.GC granules at a low density induces the formation of bone tissue which is similar to normal bone in both mechanical properties and morphology.

Animals↗
PubMed1990

Ultrastructure of Paneth cells in the intestine of various mammals.

Paneth cells in the following species were observed under an electron microscope: human, rhesus monkey, hare, guinea pig, rat, nude rat, mouse, golden hamster, and insect feeder bat. Secretory granules containing homogeneous electron-dense materials were observed in the Paneth cells of humans, monkeys, hares, guinea pigs, and bats; mouse Paneth-cell granules were bipartite (central core and peripheral halo), and the Paneth cells in rats and golden hamsters had secretory granules showing various electron densities. In humans, monkeys, and bats, immature granules near the Golgi apparatus sometimes showed bipartite substructure. The number and size of secretory granules were also diverse among various animal species. Some lysosome-like bodies were commonly observed in peri- or supranuclear regions, though the size and shape of the bodies differed from cell to cell. In apical cytoplasm, small clear vesicles (100-200 nm diameter) were more-or-less observed in all species examined, and it was especially note that rat Paneth cells contained many clear vesicles. Small dense-cored vesicles (150-200 nm diameter) were rare. It is unlikely that the various ultrastructural features of Paneth cells correlate with the phylogenetical classification.

Adult↗
PubMed1990

Mode of neuronal migration of the pontine stream in fetal mice.

The migration of immature neurons in the pontomedullary subpial region was examined in fetal mice by light and electron microscopy. Immature pontine cells were observed forming a cell strand from the ventral aspect of the fourth ventricle to the pontine flexure during the period between the 14th and 17th day of gestation. These cells were elongated and oriented parallel to the direction of migration, and displayed features of immature neurons: they contained a high concentration of ribosomal rosettes and a few cisternae of rough endoplasmic reticula, as well as Golgi apparatus, mitochondria, microtubules and centrioles. Many of the neurons extended leading processes, and these contained longitudinally-arrayed microtubules. Filopodia extending from the processes were found beneath the pia mater. Relocating cells displayed contact relationships between themselves; in the caudal part of the stream, translocating neurons were apposed to each other and fibers of various diameters, and in the rostral area of the stream, many fibers were noted, and corresponded to leading processes of relocating neurons, to which other cell bodies had close contact. From the arrangement of the immature neurons and their processes, it can be inferred that developing fibers act as guidance substrates for the translocation of embryonic pontine neurons.

Animals↗
PubMed1990

Effect of carbamylcholine on Harderian gland morphology in rats.

To determine the effect of cholinergic secretagogue on the Harderian gland of rats, several light- and electron-microscopic parameters were morphometrically assessed at different time intervals after carbamylcholine injection. In controls, two types of glandular cells (type A cells having 40-55 large vacuoles per cell profile and type B cells containing 30-38 smaller vacuoles per cell profile) and myoepithelial cells were recognized. At 5 min after injection of carbamylcholine, when rats secreted "bloody tears", many alveoli showing narrower lumina and exocytotic figures in both types of cells were observed. Some vacuoles, which were covered by thin cytoplasmic sheets, protruded into the alveolar lumina. However, there was no evidence of apocrine or holocrine secretion. At 30 min and 120 min after injection, most of the alveolar lumina were dilated, and a pronounced decrease in the number of vacuoles in the glandular cells was observed. At 300 min after injection, the secretory vacuoles in both cell types reaccumulated. Transitional forms between the two cell types were not observed. The two types of Harderian gland cells can therefore be considered independent populations rather than different secretory stages of the same cell. It appears that the secretory process of the Harderian gland of rat is affected by cholinergic stimulation of the two types of glandular cells and of myoepithelial cells.

Animals↗
PubMed1990

Molecular cloning of feline leukemia provirus genomes integrated in the feline large granular lymphoma cells.

Feline leukemia virus (FeLV) is a horizontally transmitted agent of the domestic cat which is known to be associated with wide spectrum of diseases of the hematopoietic system. In the present study, proviral DNAs of FeLV proviruses were examined in the tumor cells of natural killer cell lineage which is very rare in cats. In the chromosomal DNA of the tumor cells, 5 distinct bands corresponding to exogenous FeLV provirus genomes were detected by digestion with EcoRI which does not cut most FeLV isolates. Five clones of pLC1, pLC2, pLC3, pLC4, and pLC5 obtained from the 5 respective bands were analysed by restriction endonuclease mapping and Southern blot hybridization using gene-specific probes of FeLV. The results have clearly demonstrated that pLC4 and pLC5 contained large deletions in the pol and part of gag regions, while the full-length proviruses could be observed in pLC1 and pLC2. Furthermore, pLC3 contained part of a variant FeLV genome having an EcoRI site in its gag region. The molecular clones of defective and variant FeLV in this study may be useful for the further examination of tumorigenesis of large granular lymphoma in the cat.

Animals↗
PubMed1990

Gallbladder contractility and gallstone formation in the Richardson Ground Squirrel.

The pathogenesis of cholesterol cholelithiasis in man is probably multifactorial and the mechanism by which gallbladder stasis occurs in gallstone patients has not been studied in detail. In the present study, time-dependent changes in gallbladder motility of the Richardson Ground Squirrels were investigated. 100 of animals were examined for their contractile responses of gallbladders to CCK-OP and Ach in vitro. Also, biochemical changes of serum and bile were investigated. There were no significant differences in motility of gallbladders to CCK-OP or Ach between control and cholesterol-fed animals. The results of this study indicate that gallbladder muscle contractility remains unchanged during the dietary induction of cholesterol gallstones in the Richardson Ground Squirrel.

Acetylcholine↗
PubMed1990

The effects of nicardipine given after 10-minutes complete global cerebral ischemia on neurologic recovery in dogs.

The effect of nicardipine (NC) on neurologic recovery from ischemic insult after 10-minutes complete global cerebral ischemia was evaluated in dogs by examination of neurologic recovery score (NRS: complete recovery = 100, death = 0). Ischemia was achieved by occlusion of ascending aorta, and NC, 10 microg.kg(-1) in bolus followed by infusion of 0.33 microg.kg(-1).min(-1) for 2 hours, was administered immediately after re-establishment of circulation. The mortality at 7th day was 2/9 in the control Copyright and 1/9 in the NC group (ns). NRS on 2nd day was 52.3 +/- 6.8 in the C and 70.6 +/- 6.5 in the NC ( P < 0.05), but that on 7th day did not differ between the two groups. The numbers of dogs recovered to over 80 in NRS on the 2nd day was 1/9 in the C and 5/9 in the NC ( P < 0.05), but that on the 7th day increased to 3/9 in the C and remained at 5/9 in the NC (ns). These results suggest that NC accelerates the early neurologic recovery from ischemic damage, but influences little the final outcome.

Journal Article↗
PubMed1990

Elastic anisotropy of bivalve hinge-ligament.

Compressive stress-strain properties of an elastic ligament of a bivalve, Pseudocardium sachalinensis were investigated in the swollen state in water. The ligament is a calcified tissue, composed of calcium carbonate and insoluble protein which is rich in methionine S-oxide residue [Kikuchi, Y. and Tamiya, N., J. Biochem. (Tokyo) 89, 1975-1976 (1981)]. X-ray diffraction study showed that calcium carbonate existed only in orthorhombic aragonite form, and that all the crystal c-axes of the unit cell orientate nearly in the growing direction of the ligament. The uniaxial compression modulus for the growing direction was appreciably larger than those for the other two directions, while the anisotropy of the modulus was absent for a decalcified ligament. Thus the mechanical anisotropy of the ligament could be explained by means of the uniaxially oriented structure of aragonite crystals being dispersed in a nearly isotropic protein matrix.

Animals↗
PubMed1990

Quantitative study on osteoconduction of apatite-wollastonite containing glass ceramic granules, hydroxyapatite granules, and alumina granules.

The osteoconductive potential of apatite-wollastonite containing glass ceramic (A-W.GC), hydroxyapatite (HA), and alumina (AL) was quantitatively evaluated by implanting them as granules into rat tibiae. The amount of mature bone formed in contact with the ceramics varied depending on the ceramic materials; it reached a plateau earliest in A-W.GC and latest in AL. The bone mass at the interface showed the same results. The osteoconductive potential was suggested to be higher in bioactive ceramics than in bioinert ceramics, and to be related to the formation rate of the surface apatite layer of the bioactive ceramics.

Aluminum Oxide↗