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Biomedical subjects

Y Ohara

Publications and source records attributed to Y Ohara.

At least 19 recordsLinked to original sources
PubMed2004

Rapid determination of bovine lactoferrin in dairy products by an automated quantitative agglutination assay based on latex beads coated with F(ab')2 fragments.

UNLABELLED: This study evaluated an automated immunoassay for bovine lactoferrin (LF) in dairy products based on latex beads coated with F(ab')2 fragments. METHODS: F(ab')2 fragments were obtained by pepsin digestion of rabbit anti-bovine LF (IgG fraction) and polystyrene latex beads were coated with the F(ab')2 fragments. We used the beads to develop a rapid and homogeneous light scatter immunoassay employing an autoanalyzer (the Automated Latex assay). The Automated Latex assay was easy to perform and could rapidly determine bovine lactoferrin in lactoferrin-supplemented products. It was sensitive enough for testing products and showed good precision.

Animals↗
PubMed2004

[Surgery for acute aortic dissection concomitant with preceding axillofemoral bypass to prevent malperfusion of visceral organs and limb ischemia].

A 52-year-old man was admitted with sudden onset of epigastralgia. Abdominal X-ray showed dilated intestine and computed tomography (CT) revealed extended type A aortic dissection. Marked abdominal distention and weak pulse of right femoral artery were recognized so malperfusion of visceral organs due to narrowing true lumen compressed by thrombosed false lumen was suggested. In the operation, right axillo-right femoral bypass was established preceding to median sternotomy. This graft was used as an arterial perfusion site of cardiopulmonary bypass, and replacement of the ascending aorta was performed under hypothermic circulatory arrest and retrograde cerebral perfusion. Sign of malperfusion of visceral organs was showed for several days after the operation but it disappeared without further intervention. Axillofemoral inflow of cardiopulmonary bypass may be effective procedure in these cases.

Anastomosis, Surgical↗
PubMed2001

Association of L* protein of Theiler's murine encephalomyelitis virus with microtubules in infected cells.

We used an antibody raised against a synthetic peptide corresponding to amino acid residues 70-88 for characterizing the L* protein of Theiler's murine encephalomyelitis virus (TMEV), which is only synthesized in DA subgroup strains from an alternative AUG and is out of frame with the viral polyprotein; evidence suggests that L* protein is critical to viral persistence, demyelination, and growth in murine macrophage cell lines. It was synthesized with kinetics similar to that of other viral proteins, although less in amount. After synthesis, it remained stable in the cytoplasm and was not incorporated into virions. Immunofluorescent staining and immunoblotting of microtubule preparations demonstrated that it is associated with microtubules. Expression of L* protein also demonstrated that the 5' one third of the coding region may be responsible for the association. The association of L* protein with microtubules may be important in the disease-inducing and in vitro characters of L* protein.

Animals↗
PubMed2001

Nucleotide sequence, structural organization, and functional characterization of the small recombinant plasmid pOM1 that is specific for Francisella tularensis.

pOM1 is a recombinant 4442-bp plasmid that includes the replicon of the Francisella novicida-like strain F6168 cryptic plasmid pFNL10 and the tetracycline resistance gene (tetC) of plasmid pBR328. pOM1 can stably replicate and is maintained in Francisella tularensis biovars tularensis, palaearctica, and palaearctica var. japonica. The replicon of pOM1 includes the ori region and the repA gene. The ori region, located upstream of the repA gene includes two sets of 31- and 13-bp direct repeats (DR), with AT-rich regions preceding each of the DRs. Two putative promoters of the repA gene were found connected with the DR regions. A 40-kDa protein was encoded by the repA gene and found essential for replication. Expression of the tetC gene is regulated by an Escherichia coli sigma(70)-like promoter and is dependent on the F. tularensis strain and its environment.

Bacterial Proteins↗
PubMed2001

Genetic organization of the Francisella plasmid pFNL10.

We report here the molecular characterization of pFNL10, a 3990-bp cryptic plasmid of Francisella novicida-like F6168. The plasmid was maintained in F. novicida Utah 112 and F. tularensis LVS strains. We sequenced the entire plasmid and found six open reading frames (ORFs)-ORF1, ORF2, ORF3, ORF4, ORF5, and ORFm. ORF3, ORF4, ORF5, and ORFm are located on the same strand, and we designated it the plus strand. ORF1 and ORF2 are on the complementary strand. The ORFs appear to be arranged in two operons, one comprising ORF5 and ORF4 and the other ORF1 and ORF2. There exist two distinct promoters similar to the Escherichia coli sigma(70) promoter, one 5' to ORF1-ORF2 operon and the other 5' to ORF5-ORF4 operon. We found that in both promoters the transcriptional start is an adenosine. ORF3 is positioned in tandem with ORF5-ORF4, but has its own transcriptional start, a thymidine. However, sequence analysis revealed no recognizable promoter in physical proximity to ORF3. Sequence analysis revealed transcriptional terminators immediately downstream of the two operons. Experimental results showed that the ORF1-ORF2 terminator is authentic. But we could not definitively confirm the ORF5-ORF4 terminator. Two sets of direct repeats, one 31 and the other 13 bp, characteristic of ori are positioned between the two promoters. ORF1 encodes a protein that bears homology to the replication initiation protein RepA of various bacteria, and disruption of this ORF indeed blocked pFNL10 replication. In contrast, ORF2 disruption caused formation of plasmid multimers, suggesting aberrant replication. Our analysis also suggests that pFNL10 replicates by the theta mode. The ORF5-ORF4 operon resembles the phd-doc operon of Escherichia coli bacteriophage P1, but the significance of this similarity is unclear.

Amino Acid Sequence↗
PubMed2001

Thymol derivatives from Eupatorium fortunei.

Sixteen new thymol derivatives have been isolated from Eupatorium fortunei and their structures determined based on spectroscopic data. They were classified into three groups (i-iii) depending on the oxidation levels: (i) one oxygen function at the 9-position, (ii) two oxygen functions at the 8- and 9-positions, and (iii) three oxygen functions at the 8-, 9-, and 10-positions. The hydroxyl groups are acylated with tigloyl, angeloyl, acetyl, isobutyryl, 3-methyl-2-butenoyl, or 2-methylbutyryl moieties. The compounds having chiral centers showed no specific rotation and exist as racemic mixtures.

Chromatography, High Pressure Liquid↗
PubMed2000

Human brain capillary endothelium: 2-arachidonoglycerol (endocannabinoid) interacts with endothelin-1.

In brain, the regulatory mechanism of the endothelial reactivity to nitric oxide and endothelin-1 may involve Ca(2+), cytoskeleton, and vasodilator-stimulated phosphoprotein changes mediated by the cGMP/cGMP kinase system.(1) Endothelium of human brain capillaries or microvessels is used to examine the interplay of endothelin-1 with the putative vasorelaxant 2-arachidonoyl glycerol, an endogenous cannabimimetic derivative of arachidonic acid. This study demonstrates that 2-arachidonoyl glycerol counteracts Ca(2+) mobilization and cytoskeleton rearrangement induced by endothelin-1. This event is independent of nitric oxide, cyclooxygenase, and lipoxygenase and is mediated in part by cannabimimetic CB1 receptor, G protein, phosphoinositol signal transduction pathway, and Ca(2+)-activated K(+) channels. The induced rearrangements of cellular cytoskeleton (actin or vimentin) are partly prevented by inhibition of protein kinase C or high levels of potassium chloride. The 2-arachidonoyl glycerol-induced phosphorylation of vasodilator-stimulated phosphoprotein is mediated by cAMP. These findings suggest that 2-arachidonoyl glycerol may contribute to the regulation of cerebral capillary and microvascular function.

Actins↗
PubMed2000

Adrenergic mediation of TNF alpha-stimulated ICAM-1 expression on human brain microvascular endothelial cells.

Adrenergic innervation derived from locus ceruleus has been implicated in regulating BBB permeability and inflammatory responses associated with neurological disorders. This report demonstrates that adrenergic agents attenuate the tumor necrosis factor-alpha (TNF alpha)-induced expression of intercellular adhesion molecule-1 (ICAM-1) on cerebral microvascular endothelial cells (HBMEC) derived from human brains. HBMEC were incubated with isoproterenol (1-10 microM) alone or in the presence of propranolol (10 microM) for 30 min followed by the addition of various concentrations of TNF alpha. ICAM-1 expression on cultured HBMEC was dose-dependently upregulated by TNF alpha. Incubation with isoproterenol significantly reduced levels of ICAM-1 expression indicating the possible involvement of adrenergic agents on ICAM-1 expression. Treatment with propranolol (beta 1/beta 2-adrenergic antagonist) and butoxamine (beta 2-adrenergic antagonist), but not atenolol (beta 1-adrenergic antagonist) reversed this inhibitory effect. Isoproterenol also dose-dependently stimulated cAMP production (assayed by RIA) by HBMEC; propranolol treatment abolished this effect. These data show that the beta 2-adrenergic receptor/cAMP pathway may be partly involved in TNF alpha-stimulated ICAM-1 expression and indicate the possible involvement of adrenergic mediation of capillary function including BBB integrity.

Adrenergic Fibers↗
PubMed2000

Sarpogrelate reduces mechanical hemolysis in patients with heart valve prostheses.

OBJECTIVE: We evaluate the clinical efficacy of sarpogrelate, an antiplatelet drug that improves red blood cell deformability, to reduce the intravascular hemolysis problems suffered frequently by patients implanted with heart valve prostheses. SUBJECTS: Subjects were 34 patients undergoing mechanical heart valve replacement and having serum lactate dehydrogenase concentrations 20% above the maximum normal range. METHOD: Sarpogrelate was given daily, 100 mg orally for the first 6 months and 200 mg thereafter. RESULTS: Average serum lactate dehydrogenase decreased significantly from 423 +/- 108 IU/l, to 391 +/- 83 IU/l with the 100 mg dose, and to 361 +/- 86 IU/l with the 200 mg dose. The percentage of reticulocytes decreased from 15.5 +/- 5.3/1000 to 15.3 +/- 5.7/1000 at the 100 mg dose and 13.1 +/- 4.0/1000 at the 200 mg dose. Serum iron concentrations increased significantly from 63.2 +/- 24.8 micrograms/dl to 76.2 +/- 16.2 micrograms/dl at the 100 mg dose, and to 70.9 +/- 26.2 micrograms/dl with the 200 mg dose. CONCLUSION: Sarpogrelate is a useful drug for patients with implanted heart valve prostheses and subsequent high serum lactate dehydrogenase because it works as an antiplatelet drug and reduces mechanical hemolysis.

Adult↗
PubMed2000

Theoretical analysis of right gastroepiploic artery grafting to right coronary artery.

BACKGROUND: The right gastroepiploic artery (GEA) has been used as the second reliable arterial graft for coronary artery bypass grafting (CABG). However, concern regarding the flow competition with the recipient coronary artery has remained. METHODS: An application of in situ GEA grafting to the right coronary artery (RCA) was studied by using a theoretical model. The theoretical model of CABG was given variables; ie, the diameters and the lengths of both in situ GEA and proximal segment of the RCA, and the degree of proximal stenosis in the RCA. According to the range of these variables obtained from clinical data, the ratio of the GEA flow to the flow of the RCA distal to the anastomosis was calculated. RESULTS: Main factors to determine the flows in the two parallel paths were the inner diameters of both vessels, and the degree of the proximal stenosis. When the inner diameters of the GEA were 0.5 mm larger than that of the RCA, the GEA carried more than 50% of the total flow of the RCA distal to the anastomosis despite a moderate stenosis in the RCA. When the inner diameter of the GEA was equal to, or 0.5 mm smaller than, that of the RCA, the GEA flow was dominated by the native RCA flow unless the proximal stenosis was critical. CONCLUSIONS: If the inner diameter of the GEA is 0.5 mm larger than that of the RCA, CABG with the GEA can be applied more widely. If not, the application would basically be limited.

Coronary Artery Bypass↗
PubMed2000

Clinical results of implantation of an endovascular covered stent-graft via midsternotomy for distal aortic arch aneurysm.

UNLABELLED: We have been implanting endovascular stent grafts (EVG) via midsternotomy for distal aortic arch surgery since February 1997. The early clinical results are evaluated. METHODS: There were 11 true aneurysms (8 fusiform, 3 saccular) and one chronic type B dissection. The average age was 68 yr (63-81). EVGs were PTFE-covered two-8 bend Z stents in the first eight cases and made with the same stents and ultrathin woven Dacron grafts in the last four cases. RESULTS: Total arch replacement and aortocoronary bypass grafting were combined in one and two patients, respectively. The average retrograde cerebral perfusion time was 42+/-8 min. The cardiopulmonary bypass time averaged 211+/-26 min. All patients awoke early after operation (4.5+/-1.2 h). All but one case was extubated within 24h. There was no operative mortality, but paraplegia and cerebral infarction were complicated in one case each. Their maximum diameter (73.9+/-21.2mm) decreased significantly after operation (68.7+/-20.1mm) and one year thereafter (63.1+/-16.0 mm). True aneurysms were thrombosed completely. A chronic type B dissection revealed impending rupture due to false lumen infection one year after operation. The whole descending aorta replacement was performed but the patient died 6 months thereafter due to cerebro-vascular complication. CONCLUSION: Implantation of EVGs reduces operative invasion for distal arch surgery. This procedure should improve mortality, while long-term results have not been clarified.

Aged↗
PubMed2000

Maintenance of blood heparin concentration rather than activated clotting time better preserves the coagulation system in hypothermic cardiopulmonary bypass.

In cardiopulmonary bypass (CPB), despite heparin regimens in which the activated clotting time (ACT) is kept at more than 400 s, there is biochemical evidence of thrombin generation indicating activation of the coagulation system and increased fibrinolytic activity. Therefore, to reduce the coagulant activation has been one of the main issues in the improvement of CPB. The purpose of this study was to compare the heparin concentration with the ACT and to evaluate the effect of keeping higher heparin concentration on the coagulation and fibrinolytic systems during hypothermic CPB, employing moderate hypothermia (MHT) or deep hypothermic circulatory arrest (DHT). Heparin was either administered to maintain an ACT >400 s (ACT group) or to maintain a whole blood heparin concentration of 3 mg/kg (heparin group). At the lowest core temperature during CPB, the ACT and the heparinase ACT (unrelated to heparin concentration) were increased the most whereas the whole blood heparin concentration was less than half the initial concentration in both ACT groups of MHT and DHT. The thrombin-antithrombin III (TAT) content just after CPB in both MHT and DHT was significantly lower in the heparin group than in the ACT group. In conclusion, ACT does not reflect the whole blood heparin concentration during hypothermic CPB. Furthermore, maintenance of the higher heparin concentration during hypothermic CPB may suppress the activation of the coagulation system via thrombin inhibition. That effect was more remarkable in deep hypothermic CPB. Therefore, we believe that anticoagulation management during hypothermic CPB should be based on the maintenance of the higher blood heparin concentration.

Aged↗
PubMed2000

L* protein of Theiler's murine encephalomyelitis virus is required for virus growth in a murine macrophage-like cell line.

We sought to confirm the importance of L* protein for growth of Theiler's murine encephalomyelitis virus (TMEV) in a macrophage-like cell line, J774-1. The protein is out of frame with the polyprotein and synthesized in DA but not GDVII subgroup strains of TMEV. A recombinant virus, DANCL*/GD, which substitutes the DA 5' noncoding and L* coding regions for the corresponding regions of GDVII and synthesizes L* protein, grew with little restriction in J774-1 cells. In contrast, another recombinant virus, DANCL*-1/GD, which has an ACG rather than an AUG as the starting codon of L* protein at nucleotide 1079, resulting in no synthesis of L* protein, did not grow well. No significant difference between the rates of adsorption to J774-1 cells of these viruses was observed. RNase protection assay demonstrated that DANCL*/GD viral RNA significantly increased, whereas only a minimal increase was observed for DANCL*-1/GD. The present study suggests that L* protein is required for virus growth in macrophages.

Amino Acid Sequence↗
PubMed2000

Repair of leaking postinfarction ventricular septal defect under circulatory arrest via left thoracotomy.

We treated a 60-year-old woman for postinfarction ventricular septal defect (VSD) and closed it by the infarction exclusion method. Postoperatively she was complicated by Candida sternal mediastinitis and residual shunt of VSD. After her sternal infection came under control we repaired the leaking VSD via left thoracotomy under hypothermic circulatory arrest. She recovered well and repair of the leaking VSD under circulatory arrest via left thoracotomy seemed to be a safe and promising alternative for VSD repair.

Blood Vessel Prosthesis Implantation↗
PubMed1999

First systematic chiral syntheses of two pairs of enantiomers with 3,5-dihydroxyheptenoic acid chain, associated with a potent synthetic statin NK-104.

First systematic chiral syntheses of two pairs of enantiomers with 3,5-dihydroxyheptenoic acid chain, associated with a potent synthetic statin NK-104 are reported. A pair of syn diol isomers (NK-104 and its enantiomer) was obtained efficiently by diastereomeric resolution. The synthesis of a pair of anti diol isomers (3-epimer and 5-epimer) was accomplished effectively by the asymmetric aldol reaction followed by anti stereoselective reduction as key steps. Their purity determinations were effected by chiral HPLC analysis.

Heptanoic Acids↗
PubMed1999

Theiler's murine encephalomyelitis virus (TMEV) subgroup strain-specific infection in neural and non-neural cell lines.

GDVII subgroup strains of Theiler's murine encephalomyelitis virus (TMEV) are highly virulent and produce acute polioencephalomyelitis in mice. Neither viral persistence nor demyelination is demonstrated in the few surviving mice. In contrast, DA subgroup strains are less virulent and establish a persistent central nervous system infection which results in demyelinating disease. We previously reported a subgroup-specific infection in a macrophage-like cell line, J774-1 cells; i.e., GDVII strain does not replicate in J774-1 cells, whereas the DA strain actively replicates in these cells. In addition, this subgroup-specific virus growth is shown to be related to the presence of L* protein, a 17 kDa protein translated out-of-frame of the viral polyprotein from an AUG located 13 nucleotides downstream from the polyprotein's AUG. The present paper demonstrated that this subgroup-specific infection is observed in murine monocyte/macrophage lineage cell lines, but not in other murine cell lines including neural cells. An RNase protection assay also suggested that L* protein-related virus growth is regulated at the step of viral RNA replication. As macrophages are reported to be the major cell harboring virus during the chronic demyelinating stage, the activity of L* protein with respect to virus growth in macrophages may be a key factor in clarifying the mechanism(s) of TMEV persistence, which is probably a trigger to spinal cord demyelination.

Animals↗
PubMed1999

Expression of lymphotoxin gene inserted into Theiler's murine encephalomyelitis virus.

Theiler's murine encephalomyelitis virus (TMEV) belongs to the Picornaviridae genus. DA subgroup strains of this virus induce early, non-fatal polioencephalomyelitis followed by demyelination in the spinal cord, with virus persistence. We investigated the use of DA strain as a vector for the introduction of a foreign gene into the central nervous system. Human lymphotoxin (LT) gene was inserted in the L region, the most upstream part of the polyprotein coding region of DA genome. Expression of LT was demonstrated by an immunoblot and an enzyme-linked immunosorbent assay on BHK-21 cells that were infected with the recombinant virus. In addition, the expressed LT showed cytotoxicity against L-929 cells.

Animals↗