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Biomedical subjects

K Ono

Publications and source records attributed to K Ono.

At least 775 records · Page 43Linked to original sources
PubMed1991

Variations of the hypoxic fraction in the SCC VII tumors after single dose and during fractionated radiation therapy: assessment without anesthesia or physical restraint of mice.

Variations of the hypoxic fraction (HF) after single dose (13 Gy or 4 Gy) and during fractionated (5 fractions of 4 Gy, 1 or 2 fractions per day) radiation therapy were studied in SCC VII tumors implanted subcutaneously in the hind legs of C3H/He/Jms mice using the paired survival curve method. Whole-body irradiation was delivered to tumor-bearing mice without anesthesia or physical restraint, because both are known to increase the HF artificially. The HF decreased after a single 13 Gy dose in a biphasic fashion: extremely rapidly within 1 hr and comparatively slowly during the following 12-72 hr. On the other hand, nearly no fall of HF was observed in 24 hr following a single 4 Gy dose. Also, reoxygenation was found to occur more rapidly in the interfraction period as the number of fractions of 4 Gy increased irrespective of differences of interfraction time. However, the HF just before each radiation fraction was significantly higher than the pretreatment level for both fractionated regimens. Thus, the reoxygenation patterns observed after single low and high doses of irradiation were different from each other, and reoxygenation in each interfraction period did not always proceed in a similar manner to that after single low dose irradiation. Reoxygenation was facilitated as fractionated radiation therapy proceeded, but it was not sufficient for the HF to remain at a level comparable to that before irradiation.

Anesthesia↗
PubMed1991

A monoclonal antibody that labels Purkinje cells in the rat cerebellum.

A monoclonal antibody (MAb-1D10), generated by immunizing Balb/c mice with homogenized bovine retinal tissue, labeled the Müller cells in the bovine retina and the Purkinje cells of the rat cerebellum. In the neonatal rat cerebellum, immunoreactivity for MAb-1D10 appeared first in the ventral regions of vermis (lobuli I-III and IX-X) on the 11th postnatal day (P11), while in the dorsal vermis and cerebellar hemisphere, the immunoreactive Purkinje cells were detected on P13. Western blotting analysis disclosed that MAb-1D10 recognized bovine retinal polypeptides with mol.wt. of 48 kDa. Transplantation of the rat cerebellar primordia on 16th embryonic day demonstrated large and round cells with a linear arrangement in the grafts surviving well in the host rat striatum after 50 days of the grafting. These large cells were immunohistochemically labeled by MAb-1D10. No other cells in both the graft and the host striatum were immunoreactive to the MAb.

Animals↗
PubMed1991

Morphology of neurites from N18TG2 cell induced by protein kinase inhibitor H-7 and by cAMP.

Protein kinase inhibitor H-7 and dibutyryl (dB)-cAMP were found to induce neuritic processes in mouse neuroblastoma N18TG2 cells (36). In the present study, morphological differences between the neurites induced by H-7 and those by dB-cAMP were examined using electron microscopy (TEM and SEM) and tubulin immunohistochemistry. It was observed that: 1) The neurites induced by H-7 were relatively thin and frequently had varicosities. On the other hand, the neurites induced by dB-cAMP were thick but they had few varicosities. 2) Centrioles were frequently observed in the cells treated with dB-cAMP but were not encountered in the H-7-treated cells. 3) TEM and tubulin immunohistochemistry revealed that the main shafts of the neurites induced either by H-7 or dB-cAMP were filled with microtubules, but that the varicosities induced by H-7 contained a smaller amount of microtubules. 4) The stability to colchicine was greater in the neurites induced by H-7 than in those by dB-cAMP. From these features of the neurites, it was inferred that neurite outgrowth induced by dB-cAMP is deeply related to the formation of microtubules and that the neurites induced by H-7 were involved in other processes probably including an adhesive property of cell surfaces.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Surface blood flow and histology of human anterior cruciate ligament allografts.

We measured surface blood flow in 53 anterior cruciate ligaments (ACLs) reconstructed with allogeneic tendon grafts using laser Doppler flowmetry and examined their histology through biopsy specimens procured during second-look arthroscopy to investigate the fate of ACL allografts on a long-term basis. The age of the grafts, i.e., time from the reconstruction to the second-look arthroscopy, ranged from 6 to 89 months. Six-month grafts showed significantly higher blood flow than the other older ones from 12 to 89 months, which showed a blood flow level equivalent to normal control ACLs. Histological studies revealed that ACL allografts remodeled with time, and that they reached stability by 18 months postimplantation. These results confirmed the concepts of age-dependent remodeling of allografts and their longevity in the human knee joint.

Adult↗
PubMed1991

Differential utilization of 2',3'-dideoxyguanosine 5'-triphosphate as a substrate for various DNA polymerases.

2',3'-dideoxyguanosine 5'-triphosphate (ddGTP) was found to be an efficient substrate for DNA polymerase beta when activated DNA was used as the template.primer. Under the optimized reaction conditions with activated DNA, the rate of the incorporation of ddGTP into DNA was almost equal to that of the corresponding normal substrate dGTP. The Km value for ddGTP (1.8 microM) was smaller than that for dGTP (7.8 microM). In contrast, ddGTP was not utilized as a substrate for DNA polymerase gamma with any of the activated DNA and (dC)n.(dG)12-18 as the template primer. Other DNA polymerases such as DNA polymerase alpha, E coli DNA polymerase I and retroviral reverse transcriptase could poorly utilize ddGTP as a substrate. Some of the kinetic properties of DNA polymerase beta revealed toward ddGTP are also described. Since DNA polymerase beta plays a role in DNA repair, the present results predict possible appearance of cytotoxicity or clinical side effect(s) of 2',3'-dideoxyguanosine (ddG), known as a potent inhibitor of human immunodeficiency virus, when ddG is administered to the patients with acquired immune deficiency syndrome (AIDS) or AIDS-related complex.

DNA Polymerase I↗
PubMed1991

Preservation of ectopically induced bone in the mouse by estradiol.

The effects of estrogen on bone formation and bone resorption were examined in an experimental model of ectopic bone induction. In this experimental model, ectopic ossicles of uniform size were elicited reproducibly in three weeks by implanting pellets containing murine osteosarcoma derived bone morphogenetic protein (BMP), into the muscles of mice. Thereafter the induced ossicles showed a gradual reduction in bone mass due to negative bone balance. To estimate the effects of estrogen on bone formation and bone resorption, beta-estradiol-3-benzoate was administered exogenously to host mice from day 21 to day 41 (0.45 micrograms/g body weight, on alternate days, 10 treatments). Radiologic and histologic analysis confirmed the positive effect of estradiol on preserving bone mass over this period. Quantitative analysis showed an increase in the Ca content in ossicles after 21 days of estradiol treatment (139.1% of the baseline value on day 21). In the control group, the bone mass was reduced (47.4% of that on day 21). Bone resorption was determined by the reduction in 45Ca radioactivity from ossicles prelabeled with this radioisotope before estradiol administration. The rate of loss of the prelabeled 45Ca radioactivity was suppressed by estradiol (68.8% of prelabeled value in estradiol treated group and 87.7% in control group). The effect of exogenous estrogen on the bone forming phase of bone turnover in the ossicles was quantified by incorporation of 45Ca and 3H-proline. These bone formation parameters were increased to 2.2 and 1.9 times higher than those of the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Formation of an ipsilateral corticospinal tract after ablation of cerebral cortex in neonatal rat.

The formation of an aberrant ipsilateral corticospinal tract after unilateral cerebral cortical ablation during the neonatal period has been confirmed in the rat. The tract was chronologically studied using the antegrade horseradish peroxidase (HRP) tracing method. An aberrant ipsilateral tract is not observed 3 days after the operation. However, ipsilateral HRP positive fibers become apparent on day 7 and progressively more prominent until day 14. These results suggest that the ipsilateral corticospinal tract is composed of collateral axons originating from pyramidal neurons in the healthy ipsilateral cerebral cortex. These results also indicate that, when cerebral cortex has the damage during early postnatal life, the remaining cortical neurons which have been freed from the damage show considerable plasticity in terms of the collateral axons.

Animals↗
PubMed1991

Topical use of Xylocaine for relieving vasospasm: effect of concentration.

The spasmolytic and antispasmodic effects of Xylocaine in different concentrations were studied. Twenty-five Wistar rats were divided into five groups according to the concentrations of Xylocaine used (2 percent, 4 percent, 10 percent, 20 percent, and 40 percent). The diameters of rat femoral arteries were measured with vernier calipers under the microscope. Effects were evaluated by the percentage of the test arterial diameter compared with that of the control contralateral artery. Vasospasm of both femoral arteries was produced by administration of the fresh blood of other rats. After immersion in the blood for 10 min. Xylocaine was administered into the right femoral artery for 10 min to examine its spasmolytic effect. The effects of the concentrations shown by the percent diameter were 106 percent, 108 percent, 107 percent, 111 percent, and 106 percent, respectively. There was no significant statistical difference between each agent and its control. Thirty minutes after removal of the agent, 2 percent Xylocaine failed to maintain its spasmolytic effect, while 4 percent, 10 percent, 20 percent, and 40 percent Xylocaine did maintain it. Next, blood was again administered after vessel immersion in the agent to examine its antispasmodic effect. The effects of the concentrations were 100 percent, 114 percent, 124 percent, 152 percent, and 146 percent. There were statistically significant differences, except in the case of 2 percent Xylocaine. Twenty-percent Xylocaine demonstrated a superior antispasmodic effect. The duration of the spasmolytic effect and the antispasmodic effect were concentration-dependent, up to approximately 20 percent.

Animals↗
PubMed1991

Both induction and activation of the branched-chain 2-oxo acid dehydrogenase complex in primary-cultured rat hepatocytes by clofibrate.

Clofibrate administration to rats caused both the activation and induction of the branched-chain 2-oxo acid dehydrogenase complex in the liver; the former phenomenon occurred within the first 6 h after clofibrate administration whereas the latter occurred after 12 h. Essentially the same results were obtained with primary cultures of rat hepatocytes in the presence of 0.5 mM clofibrate, though about three-fourths of the enzyme complex in control cells (without clofibrate addition) was inactivated during a culture for 44 h, with little reduction of the enzyme amount. This was also confirmed by immunotitration analysis with antibodies raised against the purified decarboxylase and transacylase components of the enzyme complex. On the other hand, the activity of dihydrolipoamide dehydrogenase (a constituent of the complex) was little affected by clofibrate administration. The half lives of the decarboxylase and transacylase components in the primary cultures were estimated to be in the range of 22-26 h, and were unchanged in the presence of clofibrate, when determined with the use of cycloheximide and by a pulse-chase experiment. On the contrary, the rates of synthesis of these two enzyme components had increased to about 1.9-fold after 32 h cultivation in the presence of clofibrate. Thus, the increase in the synthesis of both the components resulted in induction of the complex.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1991

Histological factors contributing to favorable prognoses of soft tissue sarcomas in premenopausal patients.

The correlations of sex with various histologic factors in soft tissue sarcomas (STS) were studied in 142 adult patients over the age of 20 years. They included 63 with malignant fibrous histiocytomas, 20 with liposarcomas, 20 with synovial sarcomas, 11 with malignant Schwannomas and 28 with other forms of STS. These were divided into four groups, according to age (20-49 years and greater than or equal to 50 years) and sex. Survival rates in female patients were better than those in male patients, and the difference was significant between the 20-49 year groups (p less than 0.01). The relative frequencies in distribution of each histologic type were similar among male and female patients in both age groups. Among histological factors, mitotic counts showed a significant correlation (P less than 0.04) with sex, followed by cellularity. STS in female patients aged 20-49 years had lower mitotic counts than in patients in other groups, where it occurred with a higher frequency of low and intermediate grade tumors. The findings suggested estrogen, either directly to indirectly, to have a favorable effect on STS prognosis in premenopausal female patients.

Adult↗
PubMed1991

Thoracic myelopathy caused by ossification of the ligamentum flavum. Clinicopathologic study and surgical treatment.

The authors reviewed 14 patients with thoracic myelopathy caused by ossification of the ligamentum flavum (OLF). The predominant locality of symptomatic OLF was at the thoracolumbar junction, particularly at T10-11 followed by T11-12. At the level of the thickest OLF in each patient, there were three types of OLF from computed tomography and operative findings: a lateral type in 3 patients, diffuse in 8, and thickened nodular in 3. The diagnosis of OLF-related thoracic spinal canal stenosis was best made by enhanced computed tomography. Histologic study revealed that the developmental mode of OLF was mainly endochondral ossification. Numerous fibrocartilaginous cells were found in the increased and swollen collagen fibers forming the hypertrophic ligamentum flavum (HLF). Ossification extended along the superficial layer of HLF. The size or extension of OLF was relevant to the corresponding diathesis of spinalhyperostosis. Results of laminectomy for OLF were poor because of the high occurrence of complications early on or later deterioration. Therefore, laminoplasty is recommended as a successful procedure for OLF-related thoracic myelopathy, avoiding further local mechanical stress due to tensile force.

Female↗
PubMed1991

Os odontoideum with posterior atlantoaxial instability.

Nine patients who had os odontoideum with posterior atlantoaxial instability are reviewed. Three parameters were measured on the lateral radiographs: the distance from the os odontoideum to the spinous process of the axis in extension (Dext), the distance from the os odontoideum to the posterior arch of the atlas (Datl), and the degree of instability (Inst). Patients were classified into four groups: Group I, local symptoms (N = 3); Group II, transient myelopathy (N = 0); Group III, progressive myelopathy (N = 6); and Group IV, cerebral symptoms (N = 0). The development of cervical myelopathy was not related to degree of instability but to distance from the os to the spinous process of the axis (Dext). Dext was more than 16 mm in Group I and less than or equal to 16 mm in Group III. Five of six patients in Group III underwent myelography. Based on myelographic findings, Group III was further subdivided into two groups, Group IIIA (N = 2) and Group IIIB (N = 3), according to the following characteristics: In Group IIIA, the distance from the os to the posterior arch of the atlas was more than 13 mm, and the spinal cord was impinged between the os odontoideum and the lamina of the axis in extension and reduced in flexion. In Group IIIB, Datl was less than or equal to 13 mm, and the spinal cord was compressed at the level of the atlas during flexion and extension. Stenotic Datl of 13 mm or less specifically defined severe cervical myelopathy. Surgical treatment for cervical myelopathy in os odontoideum with posterior instability is suggested as follows: in the absence of canal stenosis of the atlas (Group IIIA), atlantoaxial fusion in a reduced position is indicated; when associated with canal stenosis of the atlas (Group IIIB), laminectomy of the atlas followed by occiput-to-C2 arthrodesis is indispensable.

Adolescent↗
PubMed1991

Cineradiographic motion analysis of atlantoaxial instability in os odontoideum.

Cineradiography was used to study six patients with os odontoideum. Atlantoaxial kinematics was analyzed with the relative motion of the atlas on the axis. In all cases, the tracing of the anterior arch was straight in the sagittal plane, whereas the posterior arch moved in two different configurations: straight and S-shaped. In cases of S-shaped configurations, the anterior translation occurred in the neutral position. Such translation could threaten the stability of the atlantoaxial complex fixed with posterior wiring because circumferential wires allow the laminas to rotate in the sagittal direction. In patients with os odontoideum, pathomechanics of the atlantoaxial joint should be examined with cineradiography in order biomechanically to determine the soundest fixation.

Adolescent↗
PubMed1991

Experimental cervical spondylosis in the mouse.

A reproducible experimental model of cervical spondylosis in mice was established by means of detachment of the posterior paravertebral muscles from the vertebrae and resection of the spinous processes along with the supraspinous and interspinous ligaments. Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degeneration, and when extended over a 6-12-month period, induced cervical spondylosis in the mice. The pathologic findings in the cervical intervertebral discs of this experimental model varied: proliferation of cartilaginous tissue and fissures in the anulus fibrosus, shrinkage of the nucleus pulposus, herniation of disc material, and osteophyte formation. The availability of this experimental model should be valuable for biochemical and biomechanical understanding of the pathogenesis of cervical spondylosis.

Animals↗
PubMed1991

Neurologic complications of surgery for cervical compression myelopathy.

Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 laminoplasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.

Cervical Vertebrae↗
PubMed1991

Electrophysiological effects of calcitonin gene-related peptide in bull-frog and guinea-pig atrial myocytes.

1. Electrophysiological effects of calcitonin gene-related peptide (CGRP) on action potentials and corresponding transmembrane currents in single myocytes from bull-frog and guinea-pig atria were studied using a whole-cell voltage-clamp method. 2. CGRP at relatively low concentrations increased the height of the action potential plateau in a dose-dependent manner in both bull-frog and guinea-pig myocytes. In addition, in bull-frog cells CGRP accelerated the early phase of repolarization, thus shortening the overall duration of the action potential. In contrast, in guinea-pig myocytes CGRP prolonged the action potential duration at all concentrations that were studied. 3. Voltage-clamp measurements demonstrated that CGRP increased transmembrane calcium current (ICa) in guinea-pig myocytes without a significant change in its voltage dependence. The ED50 value for this effect on ICa was 1.28 +/- 0.55 X 10(-8) M (n = 4). The time course of the inactivation of ICa was not affected by CGRP. 4. CGRP increased the delayed rectifier K+ current (IK) at relatively low concentrations in bull-frog atria, whereas relatively high concentrations were needed to increase IK in guinea-pig myocytes. This effect was observed even after complete inhibition of ICa. 5. CGRP had no significant effect on the inwardly rectifying background K+ current, IK1, even at very high concentrations. 6. Comparison of the time course of ICa augmentation in bull-frog and guinea-pig myocytes revealed an important difference in the effect of CGRP in these two types of cells. CGRP at maximal concentrations increased ICa transiently in bull-frog myocytes, whereas this response was sustained in guinea-pig myocytes. Isoprenaline (Iso) induced sustained increase in ICa in both species. When ICa was fully activated by Iso, CGRP at high concentrations strongly inhibited ICa in the bull-frog, whereas it had little effect on ICa in guinea-pig myocytes. 7. Intracellular application of GTP gamma S (guanosine 5'-O-(3-thiotriphosphate) 10(-4) M) greatly potentiated the CGRP effect on ICa; in contrast, GDP beta S (guanosine 5'-O-(2-thiodiphosphate), 2 x 10(-3) M) partially inhibited the CGRP-induced augmentation of ICa. Taken together, these results indicate that the stimulation of ICa by CGRP is mediated by a GTP-binding protein. 8. The observed dose-dependent changes in ICa and IK in bull-frog and guinea-pig myocytes can explain the different patterns of CGRP-induced changes in action potential shape in these two myocyte preparations.

Action Potentials↗
PubMed1991

Beta-adrenergic and muscarinic regulation of the chloride current in guinea-pig ventricular cells.

1. Single guinea-pig ventricular cells were voltage clamped using the patch clamp method combined with the pipette-perfusion technique. The voltage-dependent current systems were mostly blocked, and the background membrane conductance was measured by applying ramp pulses. 2. beta-Adrenergic effectors and related substances such as adrenaline, isoprenaline, forskolin or internal application of cyclic AMP induced a current component which showed a reversal potential near the expected Cl- equilibrium potential as well as an outward rectification in the I-V relation. It is suggested that the activation of this Cl- current was due to phosphorylation of the channel protein or related structure by the cyclic AMP-dependent protein kinase. Coincidentally with the activation of the Cl- current, the membrane capacitance of the cell decreased reversibly. 3. Acetylcholine (ACh) depressed the responses induced by beta-adrenergic stimulation and forskolin, but failed to interfere with the one induced by cyclic AMP. 4. The dose dependence of the Cl- current activation by isoprenaline or forskolin was fitted by the Hill equation, with a coefficient of 1.9 and a half-maximum concentration K 1/2 = 13 nM for isoprenaline, and with a Hill coefficient of 3 and a K 1/2 = 1.2 microM for forskolin. In the presence of 5.5 microM-ACh the dose-response relation shifted to higher doses; K 1/2 was 65 nM for isoprenaline and 3.6 microM for forskolin. 5. Washing out ACh in the presence of isoprenaline frequently caused transient overshoots of the response. When a saturating concentration of isoprenaline was used, this rebound was not observed. 6. The internal application of cyclic GMP enhanced the response of the Cl- current induced by isoprenaline or adrenaline. 7. When cyclic AMP was applied internally, the response was small in most cells. When the cell was superfused with 20 microM-IBMX (3-isobutyl-1-methylxanthine), the Cl- current was consistently induced by the application of cyclic AMP. It is suggested that phosphodiesterase activity strongly buffered the influx of cyclic AMP through the patch pipette tip. 8. We suggest that the compensatory interaction between the beta-adrenergic stimulation and the muscarinic inhibition is at the membrane level, most probably via GTP-binding proteins in activating adenylate cyclase.

Acetylcholine↗