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Biomedical subjects

Y Uratsuji

Publications and source records attributed to Y Uratsuji.

13 recordsLinked to original sources
PubMed2001

[The effects of milrinone on hemodynamics in patients undergoing cardiac surgery].

The phosphodiesterase inhibitor, milrinone is used to treat low cardiac output syndrome, especially after cardiac surgery. But there were few reports about the precise hemodynamic effects at separation from cardiopulmonary bypass (CPB). We examined the hemodynamic effects of milrinone in 24 patients undergoing elective coronary artery bypass graft (CABG). Patients were assigned to the milrinone group (n = 12) and the control group (n = 12). Before separation from CPB, milrinone was administered as a loading dose of 50 micrograms.kg-1 into the reservoir of CPB at rectal temperature 33.5 degrees C and simultaneously a continuous infusion of 0.5 microgram.kg-1.min-1 was started. In addition, dopamine and nitroglycerine were administered in both groups. Hemodynamic measurements were performed before CPB, just after the weaning from CPB, 15, 30, 60 minutes after the weaning from CPB. Cardiac index increased significantly (P < 0.01) in the milrinone group as compared with the control group. Systemic vascular resistance index and mean arterial pressure decreased significantly (P < 0.0001, P < 0.05, respectively) in the milrinone group as compared with the control group. There were no significant differences in heart rate, mean pulmonary arterial pressure, pulmonary artery occlusion pressure, mean right atrial pressure, stroke volume index, and pulmonary vascular resistance index between the two groups. These hemodynamic effects showed that milrinone supported cardiac performance after CPB for CABG.

Adult↗
PubMed1991

[Possible bronchospasm after administration of vecuronium].

A 62 year-old female developed bronchospasm after intravenous vecuronium administration. Vecuronium is reported to have major advantages over pancuronium due to the lack of significant histamine-releasing activity and cardiovascular side effects. However, macular rash, systemic collapse and bronchospasm have been reported before. The patient received cholecystectomy under general anesthesia. She had a history of urticaria when she had had a intravenous pyelography and showed positive skin test to antibiotic, ceftizoxime. During induction with thiopental plus vecuronium and on addition of vecuronium, bronchospasm was induced within five minutes in each time. Both episodes of bronchospasms were relieved with intravenous aminophylline and methylprednisolone. During the operation arterial blood gas samples were taken twice and showed no abnormal findings. Further blood samples were taken for complement C3, C4, plasma IgE and white blood cell counts. Skin test to vecuronium was also performed. In spite of these data, the mechanism of bronchospasm remained obscure. Careful attention should be paid to the use of vecuronium, especially for the patient who showed allergic response to some drugs.

Bronchial Spasm↗
PubMed1988

Growth-dependent subcellular redistribution of protein kinase C in cultured porcine aortic endothelial cells.

We have previously observed major differences in the phosphorylation of membrane proteins in sparse, proliferating versus confluent, quiescent pig aortic endothelial cells (EC) (Kazlauskas and DiCorleto, 1987). In the present study we examined whether EC growth state can influence the activity of a specific phosphorylating enzyme, protein kinase C (PKC) in cytosolic and membrane fractions of pig aortic EC. Levels of PKC were measured using two methods: 1) Ca2+ and phospholipid-dependent phosphorylation of exogenous histones using gamma-labeled [32P]ATP, and 2) [3H]phorbol-12,13-dibutyrate (PDBu) binding activity. The total amount of PKC activity in the quiescent versus proliferating cells was similar but the percentage of PKC activity in the membrane fraction correlated with the proliferative index of the cells: confluent, quiescent cultures exhibited a majority of PKC activity in the cytosolic fraction (67%), whereas sparse, proliferating cultures contained principally membrane-bound PKC (70%). We also examined the role of PKC in the mitogenic response of pig aortic EC to fetal calf serum. Following serum stimulation of sparse, serum-deprived pig aortic EC, PKC activity redistributed from the cytosolic to the membrane fraction in a rapid process that correlated with subsequent DNA synthesis. A potent activator of PKC, 12-O-tetradecanoylphorbol-13-acetate (TPA), induced a minimal mitogenic response in pig aortic EC when added alone but acted synergistically with low concentrations of fetal calf serum to greatly stimulate DNA synthesis. Furthermore, pig aortic EC treated with TPA for 24 h to down-regulate PKC exhibited only 25% of the serum-stimulated mitogenic activity of control cultures. These results suggest a role for PKC activation and translocation in the proliferation of pig aortic EC.

Animals↗
PubMed1986

A calcium-protease activator associated with brain microsomal-insoluble elements.

A factor which markedly activates Ca2+-dependent thiol protease (calpain) is associated with Triton X-100-insoluble materials, presumably structural elements such as cytoskeletons, of bovine brain microsomal fraction. This factor is extracted with 0.6 M KC1, and purified partially by sucrose density gradient centrifugation and hydroxyapatite column chromatography. The factor appears to be a heat-stable protein with an approximate Mr of 15 000. With casein as substrate this factor activates both calpain I and calpain II several-fold up to more than 10- fold without alteration of their affinity to Ca2+. Calmodulin is unable to substitute for this factor. A similar factor is associated with human platelet insoluble materials.

Animals↗
PubMed1985

Studies on the phosphorylation of myelin basic protein by protein kinase C and adenosine 3':5'-monophosphate-dependent protein kinase.

The substrate specificity of protein kinase C was studied and compared with that of cyclic AMP-dependent protein kinase (protein kinase A) by using bovine brain myelin basic protein as a model substrate. This basic protein was phosphorylated at multiple sites by both of these protein kinases. In this analysis, the basic protein was thoroughly phosphorylated in vitro with [gamma-32P]ATP and each protein kinase, and then digested with trypsin. The resulting radioactive phosphopeptides were isolated by gel filtration followed by high performance liquid chromatography on a reverse-phase column. Subsequent amino acid analysis and/or sequential Edman degradation of the purified phosphopeptides, together with the known primary sequence of this protein, revealed that Ser-46 and Ser-151 were specifically phosphorylated by protein kinase C, whereas Thr-34 and Ser-115 were phosphorylated preferentially by protein kinase A. Both kinases reacted with Ser-8, Ser-11, Ser-55, Ser-110, Ser-132, and Ser-161 at various reaction velocities. Contrary to protein kinase A, protein kinase C appears to react preferentially with seryl residues that are located at the amino-terminal side close to lysine or arginine. The seryl residues that are phosphorylated commonly by these two protein kinases have basic amino acids at both the amino- and carboxyl-terminal sides. These results provide some clues to understanding the rationale that these kinases may show different but sometimes similar functions depending on the structure of target phosphate acceptor proteins.

Amino Acid Sequence↗
PubMed1985

Activation of cellular protein kinase C and mode of inhibitory action of phospholipid-interacting compounds.

12-O-Tetradecanoylphorbol-13-acetate (TPA), that is intercalated into the cell membrane, binds a roughly stoichiometric amount of protein kinase C to produce a catalytically active complex with phospholipid. Local anesthetics and other phospholipid-interacting compounds such as chlorpromazine inhibit profoundly this complex formation in a manner competitive with phospholipid but not with TPA. A tiny change of the membrane phospholipid bilayer structure that is caused by TPA appears to facilitate this unique phospholipid-protein kinase C interaction.

Anesthetics, Local↗