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Biomedical subjects

H Ohshima

Publications and source records attributed to H Ohshima.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Coronary artery bypass grafting under the excellent heart exposure provided by the use of the coronary artery exposing tape].

We have used the coronary artery exposing tape devised by Akio Matsuura in 93 patients undergoing coronary artery bypass grafting. We could perform graft anastomosis more easily and safely by the use of this tape than by the conventional simple compression method of the heart with the gauzes. The heart was lifted anteriorly with the rotation by the tape pulled to the left side or to the caudal side. The right coronary artery branches were exposed excellently by the simple traction of the tape to the caudal side. The circumflex coronary artery branches were well exposed by one tape pulled to the left side and another tape to the right side over the heart with the counterclockwise rotation of the heart. In these procedures no complication was encountered in association with the traction of this tape.

Adult↗
PubMed1998

[Morphological basis on periodontal Ruffini endings].

The periodontal ligament has a rich sensory nerve supply which serves as a sensory apparatus in addition to tooth support. The periodontal ligament contains nociceptors and low-threshold mechanoreceptors. Stimuli applied to teeth evoke various oral reflexes, which make smooth mastication possible via the periodontal mechanoreceptors. Recent morphological and physiological studies have revealed that Ruffini endings, categorized as low-threshold slowly adapting type II (SA II), are essential mechanoreceptors in the periodontal ligament. The periodontal Ruffini endings are ultrastructurally characterized by expanded axon terminals filled with a number of mitochondria and terminal or lamellar Schwann cells. The axon terminals of the periodontal Ruffini endings have finger-like projections, i.e. axonal spines, extending into the surrounding tissue to detect the deformation of collagen fibers. As histochemical marker enzymes for the periodontal Ruffini endings, the axon terminals and terminal Schwann cells are reactive for cytochrome oxidase activity and both acid phosphatase activity and non-specific cholinesterase activity, respectively. Many experimental studies also have revealed that periodontal Ruffini endings have high potential for neuroplasticity, confirmed by intense immunoreactivity for p75-NGFR and GAP-43. Mechanical stimuli due to tooth eruption and occlusion might be a prerequisite for the differentiation and maturation of the periodontal Ruffini endings. Further investigations are needed for clarifying the involvement of growth factors and the molecular mechanism of the development and regeneration processes of the Ruffini endings.

Animals↗
PubMed1998

[The long-term anterior chest wound pain after the cardiac surgery].

We discussed on the long-term anterior chest wound pain after the cardiac surgery by using a questionnaire. The risk of the left anterior chest wound pain was high significantly in the cases using the left internal thoracic artery compared with other cases. Participation of the division of the left upper pericardium and the adjacent soft tissue was highly suggested as the cause of this pain.

Adolescent↗
PubMed1998

[Coronary artery bypass grafting performed by the simple and convenient graft supporter].

We have experienced a simple, safe and convenient technique for supporting the arterial or saphenous vein graft in the coronary artery bypass grafting. This graft supporter is made of cotton cloth with a 50 percent polyester mix. The supporter is twenty centimeters long and two centimeters wide. This supporter provides the complete fixation of the graft without the holding by the co-operater. Therefore the supporter allows very easy, safe and accurate graft anastomosis with the native coronary artery or the ascendinbg aorta. No complication was encountered in association with this procedure in 127 operations.

Coronary Artery Bypass↗
PubMed1998

[The long-term anterior chest median wound keloid after the cardiac surgery].

We discussed on the long-term anterior chest median wound keloid after the cardiac surgery by using a questionnaire. The risk of the anterior chest median wound keloid was high significantly in the cases using the bilateral internal thoracic artery compared with the cases using no internal thoracic artery. Participation of the decreased blood supply was highly suggested as the cause of this keloid formation.

Adolescent↗
PubMed1998

Left ventricular free wall rupture following mitral valve replacement.

During a 10-year period, 110 patients underwent mitral valve replacement (MVR). We experienced three left ventricular ruptures among these patients. Two had a type I immediate rupture, and one had a type III delayed rupture. Two patients (type I, III) survived after repair of the rupture. It was possible to control bleeding by manual compression with oxidized cellulose, collagen mat and fibrin glue with or without external mattress sutures. Following the repair, an intra-aortic balloon pump and sedative agents were used in both patients. In the other patient with a type I early rupture, control of bleeding was attempted by external direct suture using Teflon felt. The bleeding was controlled by this repair and the use of a left ventricular assist device, but the patient died of a brain infarction 5 days after the operation. The manual compression technique using oxidized cellulose, collagen mat and fibrin glue may be useful for minor lacerations, and for reinforcing repairs. The intra-aortic balloon pump and continuous sedation are useful for unloading the ventricle and reducing the tension on repairs.

Aged↗
PubMed1997

Dynamic Electrophoretic Mobility of Spherical Colloidal Particles in Concentrated Suspensions

A theory for the dynamic electrophoretic mobility &mgr; of spherical colloidal particles in concentrated suspensions in an oscillating electric field is proposed on the basis of Kuwabara's cell model. The dynamic mobility depends on the frequency omega of the applied electric field and the particle volume fraction phi as well as on the reduced particle radius kappaa (where kappa is the Debye-Hückel parameter and a is the particle radius) and the zeta potential zeta. A mobility formula which involves numerical integration is obtained for particles with zero permittivity and low zeta. It is found that the mobility magnitude decreases with decreasing kappaa as in the static case (omega = 0) and as in the single particle case (phi --> 0) and that it decreases with increasing omega as in the single particle case. However, the phi dependence of the mobility magnitude is much more complicated. Namely, for small kappaa the mobility magnitude decreases with increasing phi as in the static case. For large kappaa it increases with increasing phi. For moderate kappaa and not very low omega the mobility magnitude may exhibit a maximum. In all cases the omega dependence of the mobility magnitude becomes less as phi increases, that is, the dynamic mobility at any omega approaches the static mobility as phi increases. An accurate mobility formula without involving numerical integration applicable for all kappaa at zero particle permittivity and low zeta is also derived. This formula is applicable even for high zeta at kappaa --> infinity unless the dynamic relaxation effect becomes appreciable. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Facet joint asymmetry as a radiologic feature of lumbar intervertebral disc herniation in children and adolescents.

STUDY DESIGN: This study compared the incidence of facet joint asymmetry between adult and juvenile patients with lumbar intervertebral disc herniation. OBJECTIVES: To determine the different distribution of the facet joint asymmetry between the adult and juvenile patients. SUMMARY OF BACKGROUND DATA: As early as 1967, it was suggested that asymmetry of the facet joints is correlated with the development of disc herniation. There have been numerous arguments for and against Farfan's hypothesis, however, most studies were carried out on adult patients, and this hypothesis has not been verified in juvenile patients. METHODS: The study group consisted of 29 levels of 25 patients aged 12-20 years (juvenile group) and 50 levels of 33 patients aged 30-49 years (adult group) who underwent posterior discectomy. The shape of facet joints, the facet joint angle, and the moment arm angle and length were measured for each facet joint using computed tomography. Facet joint asymmetry was defined as the difference in facet joint shape or a difference of more than 10 degrees in facet joint angles between the right and left sides. The incidence of facet joint asymmetry and the relationships among the facet joint asymmetry and the location, type of disc herniation, and disc degeneration were examined in juvenile and adult groups. RESULTS: The overall incidence of facet joint asymmetry was significantly higher in the juvenile group (12 levels, 41%) than in the adult group (four levels, 8%; P < 0.01). There were no significant relationships among the facet joint asymmetry, the location, type of disc herniation, and disc degeneration. CONCLUSIONS: This study revealed that the frequency of facet joint asymmetry in the juvenile group was five times higher than that in the adult group. This result indicates that facet joint asymmetry is a radiologic feature of lumbar intervertebral disc herniation in children and adolescents.

Adolescent↗
PubMed1997

Nitric oxide induces conformational and functional modifications of wild-type p53 tumor suppressor protein.

Incubation in vitro of recombinant wild-type murine p53 protein with S-nitroso-N-acetyl-DL-penicillamine [a nitric oxide (NO)-releasing compound] has resulted in a change of p53 conformation and also in a significant decrease of its specific DNA binding activity. Similarly, upon treatment with S-nitroso-N-acetyl-DL-penicillamine (2-5 mM) or S-nitroso-glutathione (1-2 mM), human breast cancer cells (MCF-7), which express wild-type p53, rapidly accumulated p53 protein in the nuclei. This p53 protein, however, possessed a significantly decreased activity of specific DNA binding. On the other hand, lower concentrations of NO donors (0.25-0.5 mM) stimulated p53 accumulation as well as its DNA binding activity. These results suggest that excess NO produced in inflamed tissues could play a role in carcinogenesis by impairing the tumor suppressor function of p53.

Breast Neoplasms↗
PubMed1997

Suppressive effects of tranilast on the expression of inducible cyclooxygenase (COX2) in interleukin-1beta-stimulated fibroblasts.

We investigated the effects of tranilast on inducible cyclooxygenase (COX2)-mediated prostaglandin E2 (PGE2) production and enzyme induction in interleukin-lbeta (IL-1beta)-stimulated cultured dermal fibroblasts. IL-1beta enhanced PGE2 production in cultured fibroblasts. Tranilast did not affect constitutive cyclooxygenase (COX1) or COX2 activity in non-stimulated or IL-lbeta-stimulated fibroblasts. However, the COX2 expression induced by IL-1beta was inhibited by tranilast. This result, that IL-1beta-induced COX2 expression was suppressed by tranilast, was confirmed by immunohistochemical analysis. Thus, it is possible for tranilast to regulate PGE2 production by inhibiting COX2 induction.

Anti-Allergic Agents↗
PubMed1997

Nitric oxide synergistically enhances DNA strand breakage induced by polyhydroxyaromatic compounds, but inhibits that induced by the Fenton reaction.

Reactive oxygen and nitrogen species play an important role in many human diseases including cancer. We have found that incubation of pBR322 plasmid DNA with a nitric oxide (NO)-releasing compound such as diethylamine NONOate and a polyhydroxyaromatic compound such as catechol, 1,4-hydroquinone, or pyrogallol caused synergistic induction of single-strand breakage, whereas either compound alone induced much less breakage. Phenol, resorcinol, or guaiacol (O-methylcatechol) did not exhibit this synergistic effect of DNA damage with NO. The strand breakage induced by NO with pyrogallol was prevented by excess superoxide dismutase, carboxy-PTIO (an NO-trapping agent), or anti-oxidants (urate, ascorbate). Possible mechanisms for the induction of this synergistic effect of NO and polyhydroxyaromatic compounds on the strand breakage are proposed, including involvement of peroxynitrite formed from NO and O2.- derived from autooxidation of polyhydroxyaromatics. This pathway for generation of reactive species from NO and catechol-type compounds (e.g., L-dopa, catechol-estrogen) may be important in many pathological conditions, because both compounds are concurrently formed or present in vivo. On the other hand, NO dose-dependently inhibited the strand breakage mediated by 1,4-hydroquinone plus Cu2+ or Fenton reaction (H2O2, iron or copper). This inhibition could be due to formation of a complex between NO and a metal ion, inhibiting generation of reactive species from H2O2. Our results can account for contrasting activities of NO reported in relation to tissue injury. NO can play both detrimental and beneficial roles in DNA damage, depending on the type and amounts of reactive oxygen species and metal ions concurrently present.

Catechols↗
PubMed1997

Effects of hydrostatic pressure on matrix synthesis and matrix metalloproteinase production in the human lumbar intervertebral disc.

STUDY DESIGN: This study is a unique in vitro study on the effects of hydrostatic pressure on human intervertebral disc metabolism. OBJECTIVE: To investigate the effects of hydrostatic pressure on matrix synthesis and matrix metalloproteinase production in the human lumbar intervertebral disc. SUMMARY OF BACKGROUND DATA: Mechanical stress and hydrostatic pressures influence proteoglycan and protein synthesis rates in bovine articular cartilage and coccygeal discs. However, the mechanism of matrix synthesis regulation of the intervertebral disc under mechanical stress has not been elucidated. METHODS: Twenty-eight human lumbar intervertebral discs obtained from surgery and from cadavers at autopsy were used. Each tissue fraction was charged with medium in a plastic syringe and placed in a water-filled hydrostatic pressure-control vessel. The hydrostatic pressures applied were 1 (control), 3, and 30 atm (atm = atmospheres) for 2 hours. The proteoglycan and protein synthesis rates were determined by radioisotope incorporation. The production of matrix metalloproteinase-3 and tissue inhibitor of metalloproteinases-1 were measured by a one-step enzyme immunoassay method using monoclonal antibodies. RESULTS: Three atm pressure stimulated proteoglycan synthesis rates in the nucleus pulposus and inner anulus (n = 14 in each tissue). Compared with the control group, 30 atm pressure significantly inhibited proteoglycan synthesis in the inner anulus (P = 0.011). In the nucleus pulposus, matrix metalloproteinase-3 production was stimulated at a pressure of 30 atm relative to 3 atm (P = 0.014, n = 16 in each tissue). The highest tissue inhibitor of metalloproteinases-1 production showed highest values at 3 atm pressure in the inner anulus (n = 16 in each tissue). CONCLUSION: The results suggest that hydrostatic pressure influences intervertebral disc cell metabolism. A physiologic level of hydrostatic pressure (3 atm) may act as an anabolic factor for stimulation of proteoglycan synthesis and tissue inhibitor of metalloproteinases-1 production. This may be essential for maintaining the matrix of the disc. If the pressure was 30 atm or more or 1 atm or less, a catabolic effect will be predominant, with reduction of proteoglycan synthesis rate and increase of matrix metalloproteinase-3 production. Abnormal hydrostatic pressure, therefore, may accelerate disc degeneration.

Cadaver↗
PubMed1997

Dynamic Electrophoretic Mobility of a Cylindrical Colloidal Particle

Accurate approximate formulas are obtained for the dynamic electrophoretic mobility of a cylindrical hard colloidal particle in an oscillating electric field for two cases where the cylinder is in a transverse field or in a tangential field. These formulas, expressed in terms of Hankel functions and modified Bessel functions, are suitable for numerical calculation for all kappaa (kappa is the Debye-Huckel parameter and a is the particle radius) at zero particle permittivity and low zeta potentials. The dynamic mobility in a tangential field is shown to depend on kappaa in contrast to the static case, where it is independent of kappaa. The dynamic mobility of a cylinder averaged over a random distribution of orientation of the cylinder axis is roughly equal to the mobility of a sphere with a radius of 1.5 times the cylinder radius.

Journal Article↗
PubMed1997

Electrophoretic Mobility of a Polyelectrolyte-Adsorbed Particle: Effect of Segment Density Distribution

Varoqui's theory [Nouv. J. Chim. 6, 187 (1982)] for the electrophoretic mobility of a charged colloidal particle adsorbed by neutral polymers with an exponential distribution of the polymer segments is extended to the case where adsorbed polymers are charged. An analytic mobility expression is derived on the basis of the linearized Poisson-Boltzmann equation. Comparison is made with the case of particles coated with a polyelectrolyte layer of fixed thickness with uniform segment distribution.

Journal Article↗
PubMed1997

DNA damage induced by peroxynitrite: subsequent biological effects.

Nitric oxide (NO) and superoxide rapidly react to yield peroxynitrite. Peroxynitrite is a potent oxidant which reacts with proteins, lipids, and DNA. The present paper overviews the various DNA modifications induced by exposure to peroxynitrite or NO and superoxide concurrently, with special reference to the formation of 8-nitroguanine and 8-oxoguanine as well as the induction of DNA single strand breakage. In addition, we review the secondary processes that may follow the process of DNA damage, such as activation of the nuclear enzyme, poly(ADP-ribose) synthetase, apoptosis, and carcinogenesis.

Animals↗
PubMed1997

Lateral origin of the right internal thoracic artery: report of a case.

We report herein the unusual case of a patient in whom postoperative angiography following coronary artery bypass grafting (CABG) revealed a lateral origin of the right internal thoracic artery (ITA) and a normal origin of the left ITA, both of which were demonstrated to be patent and did not follow a tortuous course. The CABG had involved revascularization of the left anterior descending artery (LAD) with the right ITA, and the obtuse marginal artery with the left ITA. The patient had an uneventful postoperative course and developed no respiratory symptoms.

Coronary Angiography↗
PubMed1997

Synergistic induction of DNA strand breakage caused by nitric oxide together with catecholamine: implications for neurodegenerative disease.

Oxidative damage in neuronal cells and DNA has been implicated in the pathogenesis of various neurodegenerative diseases. We have demonstrated that DNA strand breakage is induced synergistically when plasmid DNA is incubated in the presence of both an NO-releasing compound (diethylamine NONOate, spermine NONOate, sodium nitroprusside) and a catecholamine (e.g., L-DOPA, dopamine, etc.). Either an NO-releasing compound or a catecholamine alone induced much fewer strand breaks. Tyrosine and tyramine as well as O-methylated derivatives of DOPA and dopamines did not exert this synergistic effect in the presence of NO. The DNA strand breakage induced by NO plus dopamine was inhibited by carboxy-PTIO (a trapping agent of NO and possibly other radicals), superoxide dismutase, and antioxidants such as N-acetylcysteine and ascorbate but not by HO. scavengers such as dimethyl sulfoxide, ethanol, and D-mannitol. These results suggest that the free HO. is not involved; rather a new oxidant(s) formed by the reaction between NO and catecholamine could be responsible for causing the DNA strand breakage. We propose that one of the responsible compounds is peroxynitrite (ONOO-), which is a strong oxidant and nitrating agent formed by the reaction between NO and O2.-. NO has been shown to oxidize catecholamines to form quinone derivatives, which lead to the generation of O2.- by the quinone/hydroquinone redox system. O2.- then reacts rapidly with NO to form peroxynitrite. However, it is also possible that other compounds such as NOx generated from catecholamines and NO may cause DNA damage. Our results implicate a synergistic interaction of catecholamines formed in dopaminergic neurons and NO formed by microglia or astrocytes or the two compounds produced within the same neuronal cells to produce a potent oxidant(s) which could cause damage in cells and DNA, thus playing an important role in the pathogenesis of various neurodegenerative diseases.

Antioxidants↗