Molecular orientation in thin films of bis(1,2,5-thiadiazolo)-p-quinobis(1,3-dithiole) on graphite studied by angle-resolved photoelectron spectroscopy.
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Journal Article↗
Biomedical subjects
K Kamiya
Publications and source records attributed to K Kamiya.
Molecular defect in factor IX Tokyo: substitution of valine-182 by alanine at position P2' in the second cleavage site by factor XIa resulting in impaired activation.
Utilizing polymerase chain reaction and directly sequencing the amplified exon 6 of the factor IX gene derived from a mild hemophilia Bm patient, we have identified a T to C mutation at nucleotide 20,525. This point mutation predicted a Val182 to Ala substitution in the abnormal factor IX molecule, designated as factor IX Tokyo. The patient manifested a low factor IX activity and a moderately prolonged ox-brain prothrombin time but a normal factor IX antigen level in plasma. Immunopurified factor IX derived from the patient was found to have a normal molecular weight but a reduced specific activity (23% of normal). Limited proteolysis by activated factor XI or by a snake venom-derived factor X-activating enzyme was considerably delayed, indicating the presence of structural alteration(s) most probably at or near the second enzyme-cleavage site. Once activated, however, factor IXa Tokyo was able to activate factor X normally and was inactivated by antithrombin III also in a normal fashion. The structural model of factor IXa and a docking model of factor IX and activated factor VII (factor VIIa) suggested that the Val182 to Ala substitution would not affect the local conformation of the catalytic domain. This mutation would rather loosen the fitness of the molecule into the substrate-binding pocket of factor VIIa due to a shorter side chain of the Ala substitution at the P2' position of the second cleavage site.
Adolescent↗
Increased platelet activating factor in the tracheal aspirates from neonates with patent ductus arteriosus.
We investigated platelet-activating factor (PAF) in the tracheal aspirate from 3 intubated low birth weight infants with symptomatic patent ductus arteriosus (PDA). PAF increased with the onset of symptomatic PDA and decreased to the control range soon after the ductal closure. The concentration of PAF in 26 samples taken during symptomatic PDA (median 16 pg/micrograms lipid phosphorus, range 1.4-1,200 pg/micrograms lipid phosphorus) was significantly higher than that of 31 samples from the same three patients during the periods without symptomatic PDA (median 1.9 pg/micrograms lipid phosphorus, range 0-12 pg/micrograms lipid phosphorus; P < 0.001). All 3 infants later developed chronic lung disease. These results suggest that large shunting PDA provokes PAF release to the air way of the neonate and that PAF might play a role in chronic lung disease developing after symptomatic PDA.
Ductus Arteriosus, Patent↗
Modeling of human thromboxane A2 receptor and analysis of the receptor-ligand interaction.
In order to elucidate the mode of the thromboxane A2 (TXA2) receptor-ligand interaction at the molecular level, a model for the human TXA2 receptor, a member of the G protein-coupled receptor family with seven transmembrane segments, was constructed on the basis of its amino acid sequence, which was determined recently (Hirata, M.; et al. Nature 1991, 349, 617-620). First, we made a model for the human beta 2-adrenergic receptor using its amino acid sequence and the known helix arrangement of bacteriorhodopsin. Then, a TXA2 receptor model was constructed based on the beta 2 receptor model and was used to analyze the receptor-ligand interaction. The ligand-binding pocket of the TXA2 receptor includes a serine residue from segment V, an arginine residue from segment VII, and a large hydrophobic pocket between these two residues. These results are consistent with the known properties of TXA2 and TXA2 antagonists having a hydrogen-bonding group such as hydroxyl, a carboxyl group, and a hydrophobic moiety. This model should be helpful for rational design of potent TXA2 antagonists.
Amino Acid Sequence↗
Deferoxamine reduces the reperfusion injury in isolated neonatal rabbit hearts after hypothermic preservation.
The protective action of deferoxamine, an iron chelator, against reperfusion injury following hypothermic preservation was investigated in the Langendorff-perfused hearts of neonatal rabbits. Left ventricular function and radical generation were used as parameters to evaluate functional and metabolic changes. The free radicals in coronary effluents were measured with an electron spin resonance spectroscope using a spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The hearts were preserved in cold St. Thomas solution at 4 degrees C for 6 h following cardiac arrest, then reperfused with oxygenated Krebs-Henseleit solution in a control. Deferoxamine (100 microM) was added to the perfusate just prior to reperfusion in group I, and 3 min after the start of reperfusion in group II. In the control group, the left ventricular developed pressure (LVDP) after 30-min reperfusion recovered up to 43.5 +/- 3.1% (mean +/- SD, n = 5) the preischemic value. Group I showed a significant improvement in LVDP recovery after 30-min reperfusion at 57.1 +/- 3.1% (P < 0.01 vs control), but group II did not (47.5 +/- 2.3%). When a burst of DMPO-OH signals was detected during the initial 5 min of reperfusion, the signal intensity in group I was significantly reduced to about 35-40% of the control value. Group II showed a similar intensity to the control group. Thus, we conclude that deferoxamine may exert a protective action against the dysfunction of neonatal mammalian hearts induced by preservation-reperfusion through an inhibition of iron-catalyzed radical formation.
Animals↗
Contribution of potassium accumulation in narrow extracellular spaces to the genesis of nicorandil-induced large inward tail current in guinea-pig ventricular cells.
The mechanism of nicorandil-induced large inward tail current (Itail) in single guinea-pig ventricular cells was investigated using the whole-cell patch-clamp technique. In the presence of 0.5-1.0 mM nicorandil, an activator of adenosine 5'-triphosphate (ATP)-sensitive K+ current (IKATP), a depolarization pulse causing a large outward current was followed by a large inward Itail on the repolarization step to the holding potential at -85 mV. The larger the outward current, the greater the Itail. The amplitude of Itail increased as a single exponential function (tau = 74.9 ms) as the duration of preceding depolarization was prolonged. Both the outward current and Itail were inhibited nearly completely after application of glibenclamide (1 microM), a specific blocker of IKATP. Substitution of K+ with Cs+ in both the external and internal solutions resulted in a virtual elimination of Itail. Itail was well preserved under the condition where Ca2+ entry during the preceding depolarization was largely inhibited or where external Na+ was replaced by Li+. A transient positive shift of reversal potential for the net current was observed at the peak of Itail). At 30 mM external K+ concentration, Itail was almost eliminated. From these findings, its is concluded that the Itail is a K+ current associated with an alteration of the K+ equilibrium potential (EK) following a substantial K+ efflux. This EK change is most likely explained by an accumulation of K+ in transverse tubules (T-tubules) since Itail was not induced in atrial cells in which T-tubules are poorly developed.
Adenosine Triphosphate↗
Iron responsive element-binding protein (IRE-BP) in leukemic cells: analysis using enzyme-linked immunosorbent assay and semiquantitative polymerase chain reaction.
The level of iron responsive element-binding protein (IRE-BP) in leukemic cells, which is essential for iron homeostasis and plays an important role in cell metabolism and cell growth, was measured using an enzyme-linked immunosorbent assay (ELISA). Comparing the levels in different clinical stages, the levels in CML cells in the chronic phase (mean +/- S.E., 0.270 +/- 0.110 U/mg protein, n = 9) and those in AML cells (0.150 +/- 0.104 U/mg) protein, n = 21) were significantly lower than that in normal granulocytes (0.628 +/- 0.216 U/mg protein, n = 9, p < 0.001 vs CML and AML). Analysis of IRE-BP mRNA expression in leukemic cells using semiquantitative polymerase chain reaction showed suppressed expression of mRNA as compared to normal bone marrow cells. These observations suggest that there may be dysregulation of IRE-BP expression and production in leukemic cells.
Adult↗
Protein modelling using a chimera reference protein derived from exons.
Bovine pancreatic beta-trypsin (PDB ID-code: 1TPO) which is registered in the Brookhaven Protein Data Bank (PDB) consists of four exons. The results of homology searches for each exon in the PDB showed that homologous proteins were tonin (PDB ID-code: 1TON), rat mast cell protease (PDB ID-code: 3RP2__A), kallikrein A (PDB ID-code: 2PKA__B) and kallikrein A (2PKA__B) respectively. Thus, for the three-dimensional structure prediction of 1TPO, a chimera protein was constructed from the three proteins mentioned above and the 3-D structure prediction was performed using this chimera reference protein. The modelled structure of 1TPO was energetically optimized by molecular mechanics and molecular dynamics simulation and was compared with its X-ray crystal structure registered in the PDB. The root mean square deviations (r.m.s.d.) of main chain atoms and the neighbouring active site (5 A sphere from His57, Asp102 and Ser195) between the modelled structure and the X-ray structure were 1.66 and 0.94 A respectively. Porcine pancreatic elastase (PDB ID-code: 3EST) which is registered in the PDB was used as the reference protein and the modelled structure from 3EST was also compared with the X-ray data. The r.m.s.d. of main chain atoms and that of the active site were 2.14 and 1.18 A respectively. These results clearly support the propriety of this method using the chimera reference protein.
Algorithms↗
Random process of metastasis and generation of heterogeneity in a mouse sarcoma line.
The process of metastasis was analyzed in 505-05-01 cells, an established line of a methyl-cholanthrene-induced mouse sarcoma, by tagging the cells with the pSV2neo plasmid. A dominant clone was identified which, upon transplantation together with other clones, overgrew tumors in the kidney capsule. However, when this clone was transplanted in a mouse collaterally with recessive clones, both clones grew at the same rate and metastasized to the lung at an equal frequency. This suggests that the process of metastasis in this particular sarcoma line is stochastic, the dominant population having a better chance to colonize to the lung. The dominant neomycin-resistant clone was transfected with another marker plasmid, pY3, which confers resistance to hygromycin. Results of mixed inoculation of 9 independently isolated clones revealed the hierarchy of dominance among clones. This indicated the existence of heterogeneity within the parental clone. Upon mixed inoculation with hygromycin-resistant clones, the parental clone overgrew in the tumors. This indicated that some clone had changed its phenotype to become less aggressive. Thus, the direction of phenotypic drift in vitro seems to be random in terms of behavior in vivo.
Animals↗
Granulocyte elastase alpha 1-proteinase inhibitor complex measurement in very low birthweight infants with severe intraventricular hemorrhage.
We investigated the relationship between the levels of granulocyte elastase alpha 1-proteinase inhibitor complex (E-alpha 1-PI) in plasma and severe intraventricular hemorrhage (IVH) in very low birthweight infants. The concentrations of E-alpha 1-PI and the ratio of the concentrations of E-alpha 1-PI to polymorphonuclear leucocyte counts within 24 h of birth in infants with severe IVH were significantly higher compared with those in infants without severe IVH. E-alpha 1-PI seems to be a useful indicator of IVH.
Cerebral Hemorrhage↗
Cellular and humoral immune responses to vascular components in thromboangiitis obliterans.
Cellular and humoral immune responses to vascular components were studied in 10 patients with thromboangiitis obliterans (TAO), including 3 in the mild stage of the disease and 7 in the active or severe stage. In this study the authors used the following vascular components: collagen Types I, III, IV, and V; elastin; and laminin. The cell-mediate reactivity (CMR) to these proteins was measured with an antigen-specific proliferation of peripheral mononuclear cells and evaluated by the stimulation index (SI), which is the ratio of thymidine incorporation in the presence and in the absence of antigen. The humoral immunologic response (HIR) to these vascular components was measured by an enzyme-linked immunosorbent assay (ELISA) and evaluated by the optical density (OD) index, which is the ratio of optical density (OD) in the patients' serum to that in the healthy male controls' serum. The stimulation index of collagen Types I and IV was significantly higher in patients with TAO than in healthy controls (p < 0.02). CMR to collagen Type V, elastin, and laminin was high in patients with active or severe TAO as well. However, similar statistical differences in mild TAO did not exist in the CMR. The OD index in collagen Types I, IV, and V was statistically higher in the patients than in the healthy controls (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Studies on the constituents of Turkish plants. I. Flavonol triglycosides from the fruit of Rhamnus thymifolius.
Two new flavonol glycosides have been isolated from the fruit of Turkish Rhamnus thymifolius (Rhamnaceae) and their structures were elucidated as kaempferol-3-O-alpha-L-rhamnopyranosyl(1-->3)-(4-O-acetyl)-O-alpha-L- rhamnopyranosyl-(1-->6)-O-beta-D-galactopyranoside and kaempferol-4'-O-alpha-L-rhamnopyranosyl(1-->3)-O-alpha-L-rhamnopyranosyl (1-->6)-O-beta-D-galactopyranoside based on spectral and chemical evidence.
Carbohydrate Sequence↗
[From "reactive" to "proactive". Nursing care of unconscious patients].
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Humans↗
Isolation and characterization of fibrinogenase from Candida albicans NH-1.
1. Fibrinogenase was isolated from Candida albicans NH-1 by DEAE-Cellulose, Sephadex G-75 and Sephadex G-100 column chromatographies. 2. The purified fibrinogenase gave a single band on disc polyacrylamide gel electrophoresis, isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis. 3. The enzyme preparation had a molecular weight of 13,000, isoelectric point of pH 4.2 and possessed 117 amino acid residues. 4. The purified fibrinogenase possessed capillary permeability-increasing activity. 5. The enzyme hydrolyzed fibrinogen, casein, hide powder azure, azocoll hydrolytic activities and also hydrolyzed the oxidized B chain of insulin. The cleavage sites in the oxidized B chain of insulin were identified as Asp(3)-Glu(4), Glu(13)-Ala(14), Ala(14)-Leu(15), Tyr(16)-Leu(17), Arg(22)-Gly(23), Phe(25)-Tyr(26) and Tyr(26)-Thr(27). 6. Fibrinogenase activity of this preparation was inhibited by alpha 2-macroglobulin antithrombin-III, o-phenanthroline, disodium ethylenediaminetetra acetic acid and dithiothreitol.
Amino Acid Sequence↗
[Cerebellopontine angle lipoma--case report].
Intracranial lipomas are rare. Cerebellopontine angle lipomas are extremely rare. We report a case of right cerebellopontine angle lipoma. A 47-year-old woman has been suffering from right trigeminal neuralgia for about 1 year. Neurological examination showed right 5th and 8th cranial nerve dysfunction. MRI demonstrated the high intensity mass lesion at right cerebellopontine angle. The lesion was demonstrated as negative intensity in an opposed image by using Dixon's technique. CT showed the lesion as a very low density area (-104 Hounsfield units). Subtotal removal of the tumor was performed following right suboccipital craniectomy. Pathological diagnosis was lipoma. We review the literature on this rare tumor and discuss the clinical symptoms, radiological findings and management. We suggest that the operation should be prudently performed for the case with only hearing disturbance because there is a high possibility that hearing disturbance will worsen.
Cerebellar Neoplasms↗
Effects of amiodarone and bepridil on ventricular depolarization and repolarization.
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Amiodarone↗
Effect of temporary pacing on patients with bradycardia in the acute stage following subarachnoid hemorrhage.
In nine cases of bradycardiac arrhythmia of less than 50 bpm that arose during cerebral vasospasm following aneurysmal rupture the patients were treated by temporary pacing. In patients with cerebral vasospasm, in whom autoregulation of the cerebral circulation is impaired, bradycardia aggravates the risk of decreased cerebral blood flow. This study demonstrated that temporary pacing is an effective and safe procedure in maintaining heart rate during vasospasm.
Bradycardia↗
Pulmonary surfactant apoprotein-A in neonates with different respiratory disorders.
A serial determination of pulmonary surfactant apoprotein-A (SP-A) was made on tracheal aspirates from seven intubated infants with different types of respiratory failure in the first week of life. A two-site immunoassay with monoclonal antibodies was adopted to determine the SP-A concentration. The concentrations of albumin in the same samples were also assayed, and these data were expressed as the ratio of SP-A to albumin (SP-A/albumin ratio), and evaluated against clinical data such as the arterial-alveolar oxygen tension ratio (a/APO2) or ventilatory index. In infants with respiratory distress syndrome, the SP-A/albumin ratio was initially low, and increased gradually in the first few days of life with the improvement of a/APO2 and ventilatory index. The complication of pulmonary hemorrhage due to patent ductus arteriosus (PDA) resulted in a temporary decrease in the ratio. The infant with transient tachypnea of the newborn showed higher concentration from the first day of life and, in the course of PDA without pulmonary hemorrhage, the ratio did not decrease. The cases of congenital pneumonia showed the SP-A/albumin ratio remaining low while the infection was evident. These data suggest that the SP-A/albumin ratio of the tracheal aspirate can be used for the quantitative and qualitative evaluation of endogenous pulmonary surfactant in newborn infants with different respiratory disorders.
Albumins↗