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Biomedical subjects

Y Ono

Publications and source records attributed to Y Ono.

At least 433 records · Page 24Linked to original sources
PubMed1996

Dopamine D2, D3 and D4 receptor and transporter gene polymorphisms and mood disorders.

Disturbances in dopaminergic systems have been implicated in the etiology of mood disorders. Although genetic factors also play an important role, no major gene has been identified. We conducted an association study using the dopamine D2, D3 and D4 receptor, and transporter gene polymorphisms, comparing 101 mood-disorder patients (52 bipolar and 49 unipolar) and 100 controls. Our results suggest that there is a significant association between the dopamine D4 receptor gene and mood disorders, especially major depression, but no association between the other polymorphisms and mood disorders. Further investigations are needed to clarify the clinical significance of this association in the pathophysiology of mood disorders.

Adult↗
PubMed1996

Activation of RAC-protein kinase by heat shock and hyperosmolarity stress through a pathway independent of phosphatidylinositol 3-kinase.

RAC protein kinase (RAC-PK), a serine/threonine protein kinase containing a pleckstrin homology (PH) domain, was activated by cellular stress such as heat shock and hyperosmolarity. Wortmannin, which is known as a potent inhibitor of phosphatidylinositol 3-kinase and normally inhibits growth factor-induced activation of RAC-PK, did not suppress heat-shock induced activation of RAC-PK, indicating that this stress-induced activation of the kinase is not mediated by phosphatidylinositol 3-kinase. The PH domain was indispensable for stress-induced activation of RAC PK. In heat-treated cells, PKC delta, a member of the protein kinase C family, was found to associate with the PH domain of RAC-PK. This PKC subspecies was phosphorylated in vitro by RAC-PK. The results suggest that RAC-PK may play a role in the cellular response to stress through its PH domain.

3T3 Cells↗
PubMed1996

An iron dioxygenase from Alcaligenes faecalis catalyzing the oxidation of pyruvic oxime to nitrite.

An enzyme which participated in the oxidation of hydroxylamine to nitrite from was partially purified Alcaligenes faecalis, and some of its properties were studied. The enzyme oxidized aerobically pyruvic oxime to nitrite in the presence of hydroxylamine or ascorbate. As molecular oxygen equimolar to nitrite formed was consumed in the enzymatic oxidation of pyruvic oxime to nitrite, the enzyme was thought to be a dioxygenase. It was an iron protein, and a reducing reagent was required to keep the iron in the ferrous state for the action of the enzyme.

Alcaligenes↗
PubMed1996

Characterization of the interaction between RhoA and the amino-terminal region of PKN.

The yeast two-hybrid system and in vitro binding assay were carried out to characterize the interaction between PKN and a small GTP-binding protein, RhoA. It was revealed that the region corresponding to the amino acid residues 33-111 in the amino-terminal region of PKN was sufficient to confer the ability to associate with RhoA. Each synthetic peptide fragment corresponding to the amino acid residues 74-93 and 94-113 of PKN inhibited the interaction between PKN and RhoA in the in vitro binding assay, suggesting that this region is important in the association with RhoA. The endogenous and the GAP-stimulated GTPase activity of RhoA was inhibited by the interaction with PKN, suggesting the presence of a regulatory mechanism that sustains the GTP-bound active form of RhoA.

Binding Sites↗
PubMed1996

PKN associates and phosphorylates the head-rod domain of neurofilament protein.

PKN is a fatty acid-activated serine/threonine kinase that has a catalytic domain highly homologous to that of protein kinase C in the carboxyl terminus and a unique regulatory region in the amino terminus. Recently, we reported that the small GTP-binding protein Rho binds to the amino-terminal region of PKN and activates PKN in a GTP-dependent manner, and we suggested that PKN is located on the downstream of Rho in the signal transduction pathway (Amano, M., Mukai, H., Ono, Y., Chihara, K., Matsui, T., Hamajima, Y., Okawa, K., Iwamatsu, A., and Kaibuchi, K. (1996) Science 271, 648-650; Watanabe, G., Saito, Y., Madaule, P., Ishizaki, T., Fujisawa, K., Morii, N., Mukai, H., Ono, Y. Kakizuka, A., and Narumiya, S. (1996) Science 271, 645-648). To identify other components of the PKN pathway such as substrates and regulatory proteins of PKN, the yeast two-hybrid strategy was employed. By this screening, a clone encoding the neurofilament L protein, a subunit of neuron-specific intermediate filament, was isolated. The amino-terminal regulatory region of PKN was shown to associate with the head-rod domains of other subunits of neurofilament (neurofilament proteins M and H) as well as neurofilament L protein in yeast cells. The direct binding between PKN and each subunit of neurofilament was confirmed by using the in vitro translated amino-terminal region of PKN and glutathione S-transferase fusion protein containing the head-rod domain of each subunit of neurofilament. PKN purified from rat testis phosphorylated each subunit of the native neurofilament purified from bovine spinal cord and the bacterially synthesized head-rod domain of each subunit of neurofilament. Polymerization of neurofilament L protein in vitro was inhibited by phosphorylation of neurofilament L protein by PKN. The identification and characterization of the novel interaction with PKN may contribute toward the elucidation of mechanisms regulating the function of neurofilament.

Binding Sites↗
PubMed1996

Toxic effects of hexane derivatives on cultured rat Schwann cells.

The cytotoxic effects of the following five hexane-related compounds were examined on Schwann cell DNA synthesis: 2,5-hexanedione (2,5-HD), 2-hexanol (2-OH), 2-hexanone (MnBK), 2,5-dimethylfuran (DF) and gamma-valerolactone (VL). Schwann cells were isolated from the sciatic nerves of neonatal Sprague-Dawley rats and cultured. [(3)H]-thymidine incorporation into Schwann cell nuclei was measured by scintillation spectrometry and autoradiography when hexane derivatives were added to the culture medium. All of the hexane-related compounds suppressed [(3)H]-thymidine incorporation in a concentration-dependent manner. DF was the most cytotoxic for the inhibition of Schwann cell DNA synthesis among the compounds. The finding suggests that DF-mediated cytotoxicity should be taken into account as a possible additional mechanism of hexane intoxication, especially in the impairment of mitotic cells.

Animals↗
PubMed1996

The role of the unique motifs in the amino-terminal region of PKN on its enzymatic activity.

The yeast two-hybrid system and in vitro binding assay were carried out to characterize the interaction between the amino-terminal and carboxyl-terminal region of PKN. It was revealed that the amino-terminal region containing the regulatory domain associated with the carboxyl-terminal catalytic region. A synthetic peptide, corresponding to the amino acid residues of PKN from 39 to 53, with substitution of isoleucine46 with serine was shown to become a potent substrate for PKN, and its wild type synthetic peptide inhibited the phosphorylation by PKN. These results suggest that the amino-terminal region of PKN contains the pseudosubstrate sequence and acts as an autoinhibitory region.

Amino Acid Sequence↗
PubMed1996

Determination of isonicotinic acid in the presence of isoniazid and acetylisoniazid. Studies on isonicotinic acid formation from isoniazid in isolated rat hepatocytes.

In comparison with the hepatocytes obtained from intact rats and rats pretreated with phenobarbital or 3-methylchoranthrene, the amount of isonicotinic acid (INA) formed from isoniazid (INH) increased substantially after incubation at 37 degrees C using the pretreated hepatocytes. This suggests an oxidative pathway for INA formation from INH, apart from hydrolysis. In order to explore the exact mechanism of INA formation in the hepatocytes, an HPLC assay for INA in the presence of INH and acetylisoniazid was developed. In this assay, INA was extracted after the preparation of an ion pair with tetra-n-butylammonium hydroxide, and analysed using an ODS column and a mobile phase consisting of 0.067 M potassium dihydrogenphosphate solution-methanol (96:4, v/v). The method is simple, accurate and especially suitable for INA determination after incubation of INH in isolated rat hepatocytes.

Animals↗
PubMed1996

Protein kinase N (PKN) and PKN-related protein rhophilin as targets of small GTPase Rho.

The Rho guanosine 5'-triphosphatase (GTPase) cycles between the active guanosine triphosphate (GTP)-bound form and the inactive guanosine diphosphate-bound form and regulates cell adhesion and cytokinesis, but how it exerts these actions is unknown. The yeast two-hybrid system was used to clone a complementary DNA for a protein (designated Rhophilin) that specifically bound to GTP-Rho. The Rho-binding domain of this protein has 40 percent identity with a putative regulatory domain of a protein kinase, PKN. PKN itself bound to GTP-Rho and was activated by this binding both in vitro and in vivo. This study indicates that a serine-threonine protein kinase is a Rho effector and presents an amino acid sequence motif for binding to GTP-Rho that may be shared by a family of Rho target proteins.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Identification of a putative target for Rho as the serine-threonine kinase protein kinase N.

Rho, a Ras-like small guanosine triphosphatase, has been implicated in cytoskeletal responses to extracellular signals such as lysophosphatidic acid (LPA) to form stress fibers and focal contacts. The form of RhoA bound to guanosine triphosphate directly bound to and activated a serine-threonine kinase, protein kinase N (PKN). Activated RhoA formed a complex with PKN and activated it in COS-7 cells. PKN was phosphorylated in Swiss 3T3 cells stimulated with LPA, and this phosphorylation was blocked by treatment of cells with botulinum C3 exoenzyme. Activation of Rho may be linked directly to a serine-threonine kinase pathway.

3T3 Cells↗
PubMed1996

CDKN2/p16 or RB alterations occur in the majority of glioblastomas and are inversely correlated.

p16 is involved in a cell cycle regulatory cascade that includes cyclin-dependent kinase 4 (cdk4), cyclin D1, and pRb (retinoblastoma). Alterations of each of these components have been described in primary human glioblastoma multiforme (GBM) or in GBM cell lines. Because perturbation of any component in this pathway may have similar oncogenic effects, we studied the relationship between abnormalities of CDKN2/p16 and RB, the two commonly involved tumor suppressor genes, in 55 astrocytic gliomas (42 GBMs, 8 anaplastic astrocytomas, and 5 astrocytomas). By using comparative multiplex PCR, homozygous deletions of the CDKN2/p16 gene were detected in 24 GBMs (57%) and in 2 anaplastic astrocytomas. Two additional GBMs and one anaplastic astrocytoma had allelic loss of chromosome 9p, as assessed by microsatellite polymorphisms flanking the CDKN2/p16 region. Single-strand conformation polymorphism and DNA sequencing analysis of all three coding exons of CDKN2/p16 revealed a frameshift mutation (four-bp deletion) in one of the three GBMs that had lost the remaining 9p allele. Allelic loss of chromosome 13q at the RB gene, RB gene mutations, or loss of pRb expression was noted in 14 GBMs (33%) and 2 anaplastic astrocytomas. Thirty-six of 42 GBMs (86%) had alterations of either CDKN2/p16 (n = 22), RB (n = 10), or both (n = 4); these two genetic changes, however, were relatively exclusive (P = 0.003). Furthermore, of the six GBMs without either CDKN2/p16 or RB gene abnormalities, one case had CDK4 gene amplification. These data indicate that the vast majority of GBMs probably have inactivation of the p16-cdk4/cyclin D1-pRb pathway. The findings also provide corroborative evidence that CDKN2/p16 and RB are the critical glioma tumor suppressor genes on chromosomes 9p and 13q, respectively.

Base Sequence↗
PubMed1996

Hopelessness in a community population in Japan.

The Japanese version of the Beck Hopelessness Scale was administered to a total of 154 community residents. The internal consistency (KR-20) was .86. The mean BHS score was 8.6 (SD = 3.9), approximately one standard deviation higher than the reported mean for an Irish general population. The BHS scores were found to be significantly correlated with the age and the number of people living together. Significant negative correlations were found with subjective physical fitness, self-confidence, satisfaction with accommodation and marital state, and adjustment in the work place. The mean BHS score was significantly higher among those individuals who had experienced early maternal or paternal death than those who had not.

Adult↗
PubMed1996

Collateral vessels assessed by myocardial contrast echocardiography in patients with coronary artery lesions after Kawasaki disease.

Using myocardial contrast echocardiography (MCE), coronary arteriography, and thallium-201 myocardial imaging (TMI), we examined the characteristics and the role of collateral vessels in 35 patients with coronary artery lesions after Kawasaki disease. The male/female ratio was 25:10. The patients' ages are examination ranged from 1.0 to 20.3 years (mean, 10.8 years). The age at onset of Kawasaki disease ranged from 0.3 to 11.6 years (mean, 2.6 years). The coronary artery lesions were: dilated lesions without coexistent stenotic lesions in 5 patients (14%), localized stenosis with less than 50% narrowing in 5 patients (14%), localized stenosis with 50% or more narrowing in 4 patients (11%), and obstructive lesions, such as occlusion and/or segmental stenosis, in 21 patients (60%). In the group with no stenotic lesions and the group with less than 50% localized stenosis, the perfusion area of the right coronary artery was 32.6 +/- 8.4% and that of the left coronary artery was 76.3 +/- 7.9%. The total perfusion area of the right and the left coronary arteries was 108.9 +/- 2.6%, which value was inversely correlated with age at examination (r = 0.716, P = 0.020). In the group more than 50% localized stenosis, an increase in overlap areas detected by MCE, where a perfusion defect was seen on TMI, was not found, except in 1 patient with 99% stenosis. In the patients with obstructive lesions development of collateral channels was better in the perfusion area of the occluded right coronary artery than in that of the occluded left coronary artery, and well developed collateral channels were significantly correlated with good wall motion. We conclude that overlapping perfusion occurs in younger rather than in older children without stenotic coronary systems, and this may contribute to the food development of collateral circulation in infants and young children with coronary artery lesions after Kawasaki disease.

Adolescent↗
PubMed1996

Homozygous deletions of the CDKN2/p16 gene in dural hemangiopericytomas.

While most authors currently classify dural-based hemangiopericytoma (HPC) as a distinct entity rather than as a subtype of meningioma, the histogenesis of HPC has long been debated. We have recently shown that meningiomas contain frequent mutations of the neurofibromatosis 2 gene, while HPCs do not, suggesting that HPC is genetically distinct from meningioma. In the present study, we evaluated a series of 31 dural HPCs (including 3 pairs of primary and recurrent tumor) and 26 meningiomas for alterations in the cell-cycle regulatory genes CDKN2/p16 and p53. Homozygous deletions of the CDKN2/p16 gene were detected using a comparative multiplex polymerase chain reaction assay in 7 of 28 primary HPCs (25%), but in only one of 26 meningiomas (P = 0.03). Among the HPCs with recurrence, 1 pair of 3 had a homozygous CDKN2/p16 deletion. The 1 meningioma with a CDKN2/p16 deletion was a meningothelial meningioma, without atypical or malignant features. Single-strand conformational polymorphism analysis of all three exons of CDKN2/p16 and exons 5-8 of p53 revealed no mutations in either HPCs or meningiomas. These results illustrate that homozygous deletions of CDKN2/p16 occur in HPCs and suggest that alterations of the p16-mediated cell-cycle regulatory pathway may underlie the formation or progression of some HPCs. The data also provide further genetic evidence that HPC is not a subtype of meningioma.

Gene Deletion↗
PubMed1996

The Epstein-Barr virus (EBV) alters the B cell glycolipid which is recognized by the human monoclonal antibody to i-blood group antigen.

To analyze the differentiation-related glycolipids, we have recently developed human monoclonal anti-i antibodies (mAbs) using a combination of EBV-transformation and bovine i-active glycolipid (NeuAc alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4Glc beta 1-->1Cer)-containing liposome immune lysis assay (LILA). Using complement cytolysis with these mAbs, we found the occurrence of a surface antigen (Ag) in the EBV-negative but not in the EBV-positive cell lines. The fresh EBV infection reveals that the suppressed expression of the antigen was a result of the EBV infection. The Ag recognized with these mAbs appeared to have a very low density on the B cell lines. Unexpectedly, thin layer chromatogram (TLC)-immunostaining using the mAbs revealed that the major immunoreactive substance in the EBV-negative B cell lines was an extremely minor glycolipid that was distinct from the i-active glycolipid however, this was not the case in the EBV-positive B cell lines.

Antibodies, Monoclonal↗
PubMed1996

Oxidative stress triggers tyrosine phosphorylation in B cells through a redox- and inflammatory cytokine-sensitive mechanism.

Exposure to oxidants such as hydrogen peroxide (H2O2) and gamma-ray irradiation has been recently shown to trigger tyrosine phosphorylation in B cells as does cross-linking surface immunoglobulin (sIg) by antigens or anti-immunoglobulins. We studied the mechanism by which H2O2 induced tyrosine phosphorylation in B cells and compared it with the mechanism utilized by sIg. Both anti-immunoglobulin M (anti-IgM) and H2O2 induced tyrosine phosphorylation through protein tyrosine kinase (PTK) activation. However, the tyrosine phosphorylation caused by H2O2 but not that induced by anti-IgM, was modulated by agents affecting cellular thiols and glutathione contents including dithiothreitol, 2-mercaptoethanol, and buthionine sulphoximine. Moreover, the tyrosine phosphorylation caused by the oxidant but not that induced by anti-IgM was markedly augmented by two inflammatory cytokines, tumour necrosis factor-alpha and interleukin-1 alpha, although these agents by themselves did not stimulate PTK activity nor induce tyrosine phosphorylation. These findings demonstrate that oxidative stress but not surface IgM (sIgM) ligation triggers tyrosine phosphorylation through a mechanism that is sensitive to cellular thiols and these inflammatory cytokines.

Antibodies, Anti-Idiotypic↗
PubMed1996

Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion.

A laboratory study was undertaken to determine the postural and physical characteristics and subjective stress during dynamic lifting of a usual load (10 kg) compared with during isometric lifting. The authors also aimed to clarify the effects of asymmetric lifting on these parameters. The subjects were thirteen male college students. They were asked to lift a box weighing 10 kg. They performed sixteen different lifting tasks from the floor to a height of 71 cm, involving a combination of three independent factors: two lifting modes (isometric lifting and dynamic lifting), four lifting angles in relation to the sagittal plane (sagittal plane, right 45 degree, right 90 degree and left 90 degree planes) and two lifting postures (squat and stoop). For each lifting task, strengths or forces and ground reaction forces were measured. At the end of each task, the authors asked the subjects to rate their perceived exertion (RPE) during lifting at ten sites of the body. Angle factor had a significant effect on isometric strengths and dynamic peak forces. Isometric strengths during the maximum 3 s were highest in lifting in the right 45 degree plane, followed by that in the sagittal plane, while those in the right 90 degree and left 90 degree planes were the lowest. However, peak forces in dynamic lifting were the highest in the lifting in the sagittal plane, followed by that in the right 45 degree plane, while those in the right 90 degree and left 90 degree planes were the lowest. Postural factor had a significant effect on height at peak force, which is higher in squat lifting than in stoop lifting. RPEs for the left arm, the backs and the right whole body in isometric lifting were significantly higher than in dynamic lifting of 10 kg. There were remarkably high RPEs for the ipsilateral thigh to the box in right 90 degree and left 90 degree planes during both isometric and dynamic liftings. Locations of the resultant force consisting of three component forces on the force plate were closer to the foot on the same side as the box in asymmetric lifting. Thus, some similarities and differences were found between isometric lifting and dynamic liftings regarding the indexes of strength used in this experiment. The authors consider that the subjects used the foot nearer to the box as a fulcrum during asymmetric lifting. Dynamic measurement using the 10 kg weight is less stressful than the conventional isometric measurement. It was possible to obtain the height data at peak force and time-based changes in the force and the box location during lifting only through dynamic lifting measurement. The results provide new knowledge about the biomechanical features of dynamic lifting tasks.

Adolescent↗