Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 865 records · Page 48Linked to original sources

PubMed1990

Replication and plaque formation of swine hemagglutinating encephalomyelitis virus (67N) in swine cell line, SK-K culture.

Swine hemagglutinating encephalomyelitis virus (HEV), 67N strain, adapted to suckling mouse brain, grew readily in a porcine cell line, SK-K cell culture with cytopathic effect (CPE) consisting of syncytium formation and detachment of fused cells and round cells from glass surface. After further passages in SK-K cell monolayers with undiluted culture fluid, CPE developed earlier and became complete within 48 h postinoculation (p.i.). Viral specific antigen was detected in the cytoplasm of the infected SK-K cells by indirect immunofluorescence using rabbit antiserum against the mouse-passaged virus. The SK-K-passaged virus as well as the original mouse-passaged virus formed clear plaques on SK-K cell monolayers under simple overlay medium. The plaque assay system for HEV 67N was established by studying various factors influencing the plaque formation in the SK-K cell cultures. By this system more than 10(6) PFU/0.2 ml of the virus yield was detected in the fluid phase of the infected cultures at 48 h p.i. The SK-K-passaged virus caused fatal infection in 4-week-old mice by intracerebral inoculation, but was inhibited by rabbit antiserum against the mouse-passaged virus. Plaque formation and hemagglutinating activity of the virus were specifically inhibited by antisera against the mouse-passaged and SK-K-passaged 67N virus.

Animals↗

PubMed1990

Effect of recombinant human granulocyte colony-stimulating factor on granulocytopenia in mice induced by irradiation.

We report the effect of human granulocyte colony-stimulating factor (hG-CSF) on the recovery from granulocytopenia induced by irradiation. Female 9-week old C3H/He mice were used. The irradiation schedule was as follows: Group 1 and 2 received whole-body irradiation of 1 Gy and 5 Gy, respectively, on day 0; Group 3 and 4 received whole-body irradiation of 0.5 and 1.0 Gy, respectively, for 5 consecutive days; Group 5 received upper hemibody irradiation of 3 Gy for 5 consecutive days. Daily subcutaneous injections of G-CSF (3 x 10(5) Unit/mouse) or 0.3 ml of saline to each group were started from the day after the first irradiation and continued for 18 days. Mice were sampled randomly from each group, and the total number of leukocytes, erythrocytes of peripheral blood, nucleated cells in femur, and spleen weight were counted and measured, respectively, on day 0, 3, 5, 7, 9, 12, and 18. The leukocyte counts decreased with an increase in radiation doses. In Group 1 and 2 mice, G-CSF enhanced the leukocyte count more than saline. In Group 3 mice, the recovery of leukocytopenia was facilitated by G-CSF, but in Group 4 mice, G-CSF had no effect on the leukocyte count decrease or on leukocytopenia recovery. In Group 5 mice, G-CSF greatly affected leukocytopenia recovery. Increase in spleen weight paralleled the peripheral leukocyte count. Daily administration of recombinant hG-CSF accelerated the granulocytopenia recovery which was induced by irradiation, and it may be a useful therapeutic agent for treating myelosuppressive cases.

Agranulocytosis↗

PubMed1990

Retrovirus-mediated gene transfer into mouse cerebellar primary culture and its application to the neural transplantation.

To develop a procedure for the transplantation of genetically modified brain primary cells, we transplanted cultured mouse cerebellar cells infected with recombinant retroviruses into the cerebella of adult mice and examined the expression of introduced gene-products in the host cerebellum after transplantation. After infection of cultured cerebellar cells with recombinant retroviruses harboring chloramphenicol acetyltransferase (CAT) gene, we selected only virus-infected cells for transplantation by culturing the cells in medium containing G418 for 3 weeks. CAT was continuously expressed in the cultured cerebellar cells during the 3-week incubation, but by immunoblotting analysis with antiglial fibrillar acidic protein (GFAP) or antineurofilament protein (NFP) antiserum the population of cultured cerebellar cells was found to change during the incubation. Immunocytochemical analyses using anti-CAT antiserum demonstrated that the transplanted cell mass containing CAT-positive cells was detectable in the cerebellum up to 3 weeks, but not 3 months after the transplantation of G418-selected cells into the cerebella of 7-week-old mice.

Animals↗

PubMed1990

Fetal hypothalamic brain grafts to the ventromedial hypothalamic obese rats: an immunohistochemical, electrophysiological and behavioral study.

Fetal ventromedial hypothalamic (VMH) tissue was transplanted into or around the third ventricle of adult Fischer 344 rats to determine if transplanted VMH tissue could reverse the hyperphagia and obesity produced by bilateral VMH electrolytic lesions. Host VMH-lesioned rats received stereotaxic implants of 13 to 19 postcoitus fetal VMH tissue from normal Fischer pups. The results show that: 1) Fetal VMH tissue survived in the brain (mainly in the third ventricle) of VMH-lesioned rats. The optimal survival and differentiation was at the gestational age of 13 days; 2) VMH-lesioned rats containing VMH grafts tended to consume less food than the controls, but this was not statistically significant. Neural grafts that could compensate the hyperphagia and obesity produced by the VMH lesions (in comparison to the controls) were those placed into the third ventricle; 3) Electrophysiological evidence demonstrated that VMH grafts contain glucoreceptor neurons in grafts not only located in the third ventricle, but also in the thalamus; 4) Immunohistochemical evidence showed the presence of serotonin, beta-endorphin and substance P immunoreactive fibers in the grafts. These results indicated that transplants of fetal VMH tissue in the brain of bilateral VMH-lesioned adult rats may have some functional effects (depending on the location of the graft).

Action Potentials↗

PubMed1990

Differential inhibition of the activities of reverse transcriptase and various cellular DNA polymerases by a traditional Kampo drug, sho-saiko-to.

A traditional Kampo drug, Sho-saiko-to, composed of several herb extracts, differentially inhibited the activities of reverse transcriptase and human cellular DNA polymerase alpha and beta. Reverse transcriptases from murine leukemia virus and human immunodeficiency virus were inhibited by over 80% and 50%, respectively, in the presence of 100 micrograms/ml Sho-saiko-to, whereas DNA polymerase alpha was much less sensitive to inhibition by this drug than were the reverse transcriptases. DNA polymerase gamma was not inhibited by this drug at concentrations of up to 500 micrograms/ml. Only DNA polymerase beta was moderately inhibited by Sho-saiko-to. Thus, it has been shown that the inhibition by Sho-saiko-to is relatively specific for reverse transcriptase and that the drug contains as yet unidentified inhibitory substance(s) for reverse transcriptase.

Animals↗

PubMed1990

Utilization of 2',3'-dideoxyguanosine 5'-triphosphate as an inhibitor and substrate for DNA polymerase alpha.

The activity of DNA polymerase alpha was strongly inhibited by low concentrations (less than 1 microM) of 2',3'-dideoxyguanosine 5'-triphosphate (ddGTP) in the presence of Mn2+, although the incorporation of [3H]ddGTP into the product DNA was not detectable under the same reaction conditions. ddGTP competitively inhibited the incorporation of [3H]dGTP into the DNA. The Kis of DNA polymerase alpha for ddGTP were as low as 0.035 microM with activated DNA and 0.044 microM with (dC)n.(dG)12-18 as respective template.primers. By increasing [3H]ddGTP concentration (greater than 1 microM), however, it became an efficient substrate for DNA polymerase alpha. Under the assay conditions with activated DNA as the template.primer and Mg2+ as the divalent cation, the maximum incorporation rate of [3H]ddGTP reached 14.5% when compared to that of the corresponding normal substrate [3H]dGTP. These results indicate that the observed inhibition of DNA polymerase alpha activity by low concentrations of ddGTP in the presence of Mn2+ cannot be explained by the incorporation of ddGTP followed by chain termination of the growing DNA, and the results also support the previously presented hypothesis that the inhibition is caused by competition between the dideoxynucleotide inhibitor and its corresponding deoxynucleotide substrate at the same enzyme binding site. Thus ddGTP acts as an inhibitor or a substrate for DNA polymerase alpha depending on its concentration and the species of divalent cation. Some of the kinetic properties of DNA polymerase alpha connected with ddGTP are also described.

Binding, Competitive↗

PubMed1990

Dietary copper, simple sugars, and metabolic changes in pigs.

Inadequate dietary copper is known to result in undesirable metabolic changes in rats and humans. Abnormal cardiac function, leading to sudden death, is a common finding when copper deficient rats are fed a 62% fructose diet. To further study the apparent mineral-carbohydrate relationship to cardiac physiology, 3 male and 3 female swine were randomly assigned to four groups (6 pigs per group) which were fed low copper (1.5 ppm) or copper supplemented (40 ppm) diets with 20% of calories from either fructose or glucose for 10 weeks. In agreement with results from other animal studies, copper deficient swine exhibited decreased plasma ceruloplasmin, erythrocyte superoxide dismutase and plasma lysyl oxidase activities and lowered serum copper. The copper deficient fructose group had the lowest aortic lysyl oxidase activity and hematocrit when compared to the other groups. The relative heart weight in the copper deficient fructose group was 93% greater than the other three dietary groups. The livers of copper deficient fructose fed pigs were also significantly larger. Two enzymes related to cardiac and hepatic function, aspartate and alanine aminotransferase were also measured. Copper deficiency significantly lowered alanine aminotransferase but there was no dietary effect on aspartate amino-transferase. The results of this project indicate that the pig is a sensitive model for the study of cardiovascular abnormalities which occur when fructose is consumed with a low copper diet.

Journal Article↗

PubMed1990

Matrix vesicle calcification of ectopically induced osteoid tissue in 1-hydroxethylidene-1,1-bisphosphonate (HEBP)-treated mice.

The effects of 1 hydroxethylidene-1, 1-bisphosphonate (HEBP) on the mineralization of osteoid induced ectopically by a murine, osteosarcoma-derived, bone-inducing substance was examined at the ultrastructural level. Samples of Dunn osteosarcoma were chemically processed, lyophilized into pellets of uniform dimensions and protein content, and implanted into the back muscles of male, 4 week old, ddY mice. In control animals injected intraperitoneally (i.p.) with saline each day for 30 days, the pellets exhibited ectopic cartilage and bone formation in a sequential manner consistent with endochondral ossification. Daily administration of HEBP (30 mg/kg i.p. per day) to animals over the same period produced wide anastomosing strands of osteoid and haematopoietic marrow in the pellets. Electron microscopical examination revealed a tightly packed organization of collagen fibrils with many membrane bounded organelles or matrix vesicles (0.05-0.3 micron diameter) dispersed throughout this nonmineralized matrix. After withdrawal of HEBP, mineralization proceeded initially within matrix vesicles and secondarily by involvement of the surrounding collagen fibrils. In pellets retrieved at 30 days after HEBP withdrawal, most of the matrix had been mineralized and remodeled to reveal thin bony trabeculae and an overall histologic appearance similar to that seen in the control pellets. This model of ectopic bone formation permits clear visualization of the sequence of mineral nucleating events in osteoid in the absence of an established mineralizing front. The results add further support to the hypothesis that matrix vesicles are directly responsible for the initiation of mineralization in bone.

Animals↗

PubMed1990

Reorganization of the corticospinal tract following neonatal unilateral cortical ablation in rats.

The corticospinal tract in the rat after neonatal ablation of the unilateral cerebral cortex was studied morphologically and histochemically using the retrograde and antegrade horseradish peroxidase (HRP) tracing methods. The normal corticospinal tract in the lumbar cord was composed of a number of small and some large axons. In the atrophic corticospinal tract related to the ablated cerebral cortex, the small axons were decreased in number two weeks after the operation. However, new myelinated small axons appeared around day 28 and their diameters increased gradually from after day 56 to day 84. The original large axon in the atrophic corticospinal tract was much more increased in size than that in the corticospinal tract of the non-operated-on control. When HRP was injected into the left cervical cord of the adult rat whose right cerebral cortex had been ablated during the neonatal period, a considerable number of HRP-labeled neurons was seen in the healthy left cerebral cortex. When the corticospinal tract was traced antegradely by injecting HRP into the healthy left cerebral cortex, an aberrant corticospinal tract reaching into the ipsilateral dorsal funiculus was observed. These results give a morphological basis for the well known fact that children who have had brain damage during the neonatal period and early infancy have the capacity for recovery of motor function.

Animals↗

PubMed1990

Use of the micronucleus assay for the selective detection of radiosensitivity in BUdR-unincorporated cells after pulse-labelling of exponentially growing tumour cells.

To determine the radiosensitivity of non-S-phase tumour cells in vitro, survival curves of SCC VII tumour cells were obtained after a short block with hydroxyurea. Dose-response curves of micronucleus (MN) frequency appearing in non-S-phase cells were also determined by excluding S-phase cells with immunofluorescence staining to 5-bromo-2'-deoxyuridine (BUdR). Both the dose-response curves of MN frequency and survival curves were analysed by a linear-quadratic model (surviving fraction = exp (-alpha D-beta D2), MN frequency = aD+bD2+c). A good correlation between the alpha/beta and alpha/beta ratios was observed. In both BUdR-unincorporated and asynchronous cell cultures, the regression lines between the surviving fraction and micronucleus frequency were statistically identical. Therefore, it was shown that cell survival curves, which cannot be obtained directly by the routine colony-formation technique, can be calculated using the micronucleus frequency and the regression line in asynchronous cell cultures. Therefore, it should be possible to detect the response to irradiation of quiescent cells in tumours using the immunofluorescence staining to BUdR and the MN frequency assay.

Bromodeoxyuridine↗

PubMed1990

Oxalate crystal deposits in the heart in chronic renal failure: an experimental study.

The present study was undertaken to evaluate three factors which may contribute to the myocardial deposition of calcium oxalate in 5/6 nephrectomised rats: (1) increased plasma oxalate, (2) elevated plasma ionised calcium, and (3) local myocardial tissue damage. A simple increase in plasma oxalate concentrations produced by injection of sodium oxalate did not cause deposits in the heart. Increased plasma ionised calcium combined with elevated plasma oxalate for 60 days was likewise unimportant with regard to cardiac deposits. However, when local tissue damage was added by heterotopic cardiac transplantation, deposition of crystals was seen in four or five allografts damaged by rejection. In this model the rat's own heart was not affected. Although an increase in plasma oxalate values is not without significance, the present findings suggest that local tissue damage is a more important factor in the myocardial deposition of oxalate crystals in renal failure.

Animals↗

PubMed1990

Structure of an allergenic pentasaccharitol, Gp-1 beta-b6, isolated from a sea squirt antigen, Gi-rep, as a minimum structural unit responsible for its allergenicity.

An allergenic pentasaccharitol, Gp-1 beta-b6, was isolated as a minimum structural unit responsible for the allergic reaction in skin of patients with sea squirt allergy from a saccharitol fraction, Gp-1 beta-b, that had been liberated by beta-elimination from a glycopeptide in a Pronase digest of a sea squirt antigen, Gi-rep. Methylation/GC-MS and FAB-MS analyses indicated the sugar sequence of Gp-1 beta-b6 to be GalNAcl----2Fucl----(GalNAc1----) 3,4GlcNAc1----3GalNAc-ol. To analyze the structure in more detail, Gp-1 beta-b6 was labeled with p-aminobenzoic acid ethyl ester (ABEE), i.e., the reducing terminal 3-O-substituted GalNAc-ol of the saccharitol was oxidized to 2-O-substituted L-ThrNAc with equimolar periodate, and the resultant aldehyde was labeled with ABEE by reductive amination. The ABEE-labeled Gp-1 beta-b6 was subjected to sequential exoglycosidase digestion with beta-N-acetylhexosaminidase, alpha-N-acetylgalactosaminidase, and alpha-fucosidase, and the digests were chromatographed on an HPLC column of TSK gel Amide 80. From the results of the HPLC, methylation/GC-MS, and FAB-MS analyses of the digests of the labeled substrate, the structure of Gp-1 beta-b6 was determined to be GalNAc alpha 1----2Fuc alpha 1----3(GalNAc beta 1----4)GlcNAc beta 1----3GalNAc-ol. Enzymatic elimination of either the non-reducing terminal beta-GalNAc or the non-reducing terminal alpha-GalNAc led to inactivation of the allergenic pentasaccharitol. Accordingly, it is possible that the allergenic saccharitol contains two disaccharide units as the allergy-specific epitopes, one GalNAc alpha 1----2Fuc alpha 1---- and the other GlcNAc beta 1----4GLcNAc beta 1----.

Allergens↗

PubMed1990

Mechanisms of inhibition of various cellular DNA and RNA polymerases by several flavonoids.

Four flavonoids (i.e., baicalein, quercetin, quercetagetin, and myricetin), known to be inhibitors of HIV-reverse transcriptase, have been shown to be more or less inhibitory to the activities of various cellular DNA and RNA polymerases. The degree of the inhibition varied depending on the combination of the flavonoid and the enzyme species: baicalein was moderately inhibitory to DNA polymerase gamma and E. coli DNA polymerase I; quercetin was strongly inhibitory to DNA polymerase beta and E. coli RNA polymerase and moderately inhibitory to DNA polymerase I; quercetagetin was a potent inhibitor for all of DNA polymerases alpha, beta, gamma, and I and RNA polymerase; myricetin was a strong inhibitor of DNA polymerases alpha and I and RNA polymerase. However, terminal deoxynucleotidyltransferase was virtually insensitive to inhibition by these flavonoids. The inhibition by the flavonoids was due to competition with the template.primer in the case of the DNA polymerases, whereas the inhibition was due to competition with the triphosphate substrate (GTP) in the case of RNA polymerase. The Ki values of these flavonoid inhibitors for DNA and RNA polymerases was determined.

Animals↗

PubMed1990

Neuromuscular effects of respiratory and metabolic acid-base changes in vitro with and without nondepolarizing muscle relaxants.

The effects of metabolic (bicarbonate, [HCO3]) and respiratory (carbon dioxide, PCO2) acid-base changes on indirectly elicited twitch tension with and without nondepolarizing neuromuscular blocking agents were compared in a rat phrenic nerve-hemidiaphragm preparation. Ionized calcium [Ca2+] and magnesium [Mg2+] concentrations in the modified Krebs' solution were measured and kept constant. Likewise, twitch was altered when pH changes were produced by altering either PCO2 or [HCO3]. Decreasing pH either by increasing PCO2 or by decreasing [HCO3] significantly decreased (P less than 0.01) twitch, by 9.5 +/- 0.6 (SEM, n = 8) and 10.6 +/- 1.5%, respectively. Increasing pH by decreasing PCO2 or by increasing [HCO3] significantly increased (P less than 0.01) twitch, by 5.6 +/- 0.9 and 7.9 +/- 0.6%, respectively. After a partial depression of twitch by nondepolarizing neuromuscular blocking agents, the effects of PCO2 and [HCO3] changes were again assessed. Decreasing pH by increasing PCO2 or by decreasing [HCO3] intensified d-tubocurarine (dTc) (28.2 +/- 1.6 and 32.0 +/- 2.9%, respectively) and vecuronium (23.0 +/- 1.4 and 36.8 +/- 3.2%, respectively) block, whereas it reversed metocurine (1.2 +/- 2.2% NS and 2.9 +/- 1.3%, respectively) and pancuronium (8.3 +/- 1.5 and 11.5 +/- 3.0%, respectively) block. Conversely, increasing pH by decreasing PCO2 or by increasing [HCO3] antagonised dTc (12.8 +/- 2.2 and 13.6 +/- 1.8%, respectively) and vecuronium (25.3 +/- 1.7 and 25.0 +/- 3.0%, respectively) block, whereas it potentiated metocurine (4.2 +/- 0.6 and 8.0 +/- 1.1%, respectively) and pancuronium (11.0 +/- 1.2 and 17.5 +/- 2.0%, respectively) block. Except where indicated, all changes in block described above were statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Imbalance↗

PubMed1990

Motion analysis of the cervical spine in athetoid cerebral palsy. Extension-flexion motion.

Frequently instability and premature onset of spondylosis of the cervical spine are found in athetoid cerebral palsy (CP) patients. These structural abnormalities appear to be related to athetoid motion of the neck in CP. Through motion analysis, the authors aimed to clarify the abnormalities of cervical motion that could precipitate structural abnormalities. The gross characteristic feature of cervical motion in athetoid CP is "whip movement." Both velocity and acceleration during extension-flexion motion were greater than in normal subjects, especially at the upper cervical levels. Also, a sudden increase in velocity and acceleration occurred during rapid motions at certain levels, followed by a larger range of motion of the cervical spine. Such kinematic abnormalities were thought to generate a greater shearing force and bending moment exerted on the corresponding cervical articulations-discs and facets. Olisthetic instability often accompanied disc degeneration at the upper cervical levels. A large range of extension--flexion motion of the cervical spine, analogous to a cantilever, caused a repeated bending moment of extraordinary magnitude and was regarded as a precipitative factor for disc degeneration and osteophytosis common at the middle and lower levels of the disc.

Adult↗

PubMed1990

Lateral rhachotomy for thoracic spinal lesions.

Capener's "Lateral Rhachotomy" was modified by additional excision of the pedicle, articular facets, part of the lamina, and a posterior half of the vertebral bodies on one side through a transpleural approach to the thoracic spine, and a retroperitoneal approach to the lumbar spine. The aim was to excise a space-occupying lesion, which exists in front of the thoracic or lumbar spinal cord, safely. This modification enable the authors to expose more than 50% of the spinal canal, and decompress it from its anterior, lateral, and posterior compressing mass. The utmost important point of this procedure is the excision of the lesion under the direct visualization of the dura. In ossification of the posterior longitudinal ligament (OPLL), the dura is usually indented by the thick bony mass, and the lesion extends over a few segment with adhesion. Using "Modified Lateral Rhachotomy," it was possible to explore three or four vertebral levels in continuity through the same skin incision. In the present report, the authors described their "Modified Lateral Rhachotomy" procedure, and reviewed the case material.

Female↗

PubMed1990

FK506, a novel immunosuppressive agent, induces antigen-specific immunotolerance in active Heymann's nephritis and in the autologous phase of Masugi nephritis.

FK506 is a new drug which has potent immunosuppressive activity. We studied its immunosuppressive effects on active Heymann's nephritis and the autologous phase of Masugi nephritis. The induction of active Heymann's nephritis was completely suppressed by FK506 injected simultaneously with the antigen (day 1) and then daily for 14 days at a dose of 0.64 mg/kg per day or more. With a lower dosage of this agent, antibody production and immune deposits in the glomerular basement membrane occurred despite the suppression of proteinuria. Similar results were obtained in rats on other treatment schedules (1-7 days or day 8-14 days duration). Rats that were prevented from developing Heymann's nephritis or the autologous phase of nephrotoxic antiserum nephritis by FK506 treatment exhibited a suppressed immune response to a second immunization of the same antigen even 4 weeks after cessation of drug administration: however, they developed antibodies when inoculated with other antigens. Rat peripheral leucocyte counts and serum creatinin were not remarkably influenced by the administration of FK506. These results indicate that FK506 has potent immunosuppressive activity, and it is suggested that it is able to induce an antigen-specific immunotolerance.

Animals↗

PubMed1990

Natural infection of nude mice with low-virulent mouse coronavirus.

The outbreak of wasting disease of nude mice occurred in the laboratory colony of a Pharmaceutical Company. The viruses producing cytopathic effect with syncytium formation were isolated from the wasted nude mice by DBT cells, and were identified as mouse coronavirus by direct immunofluorescence. The nude mouse colony was closed and all the nude mice (about 500) were killed by the reason of disease control. At autopsy about 60% of nude mice showed necrotic hepatitis. By the virus isolation to see the source of contamination, viruses were isolated from the feces of apparently healthy mice of ICR, CDF1, DBA/2 and C3H, and from human cancer cell line stocked in liquid nitrogen. In experimental infection, the isolates produced only mild hepatitis in ICR mice treated with cortisone. By cross-neutralization test, the nude isolate reacted closely with the virus from C3H mice but not with the virus from cancer cell line. The isolates from nude and C3H mice produced experimentally wasting disease with necrotic hepatitis in nude mice. These findings suggest that wasting disease in nude mice might be caused by low-virulent mouse coronavirus shed in feces from C3H mice introduced before the outbreak of disease.

Animals↗