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Y Sawa

Publications and source records attributed to Y Sawa.

At least 199 records · Page 11Linked to original sources
PubMed1994

Purification and characterization of an acid phosphatase from Mycoplasma fermentans.

An acid phosphatase associated with the cell membranes of Mycoplasma fermentans was released from the membranes with Triton X-100, then purified by ion-exchange chromatography on DEAE-Sephacel and CM-Sepharose, followed by affinity chromatography on Con A-Sepharose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed a single band with a molecular mass of 31.2 kilodaltons. The enzyme activity toward p-nitrophenyl phosphate was enhanced remarkably by Cu2+, Co2+ and Mg2+, but the activity was not inhibited by EDTA. The enzyme dephosphorylated O-phospho-L-tyrosine as well as p-nitrophenyl phosphate, but not O-phospho-L-threonine, O-phospho-L-serine, glucose-1-phosphate, phosphoryl choline and adenosine triphosphate. The level of the O-phospho-L-tyrosine phosphatase activity was the highest in Mycoplasma faucium and the second highest in Mycoplasma fermentans of all tested human mycoplasmas.

Acid Phosphatase↗
PubMed1994

Purification and characterization of membrane protein (90 kDa) from Mycoplasma salivarium, which binds immunoglobulin (Ig) G Fc fragment.

A 90 kDa protein of Mycoplasma salivarium was released from cell membranes of the organism with Triton X-100 and purified by ion-exchange chromatography and chromatofocusing. The protein was eluted at pH 5.5 by chromatofocusing. The protein was shown to react with the Fc fragments of IgG from human and nine different animal species and did not distinguish between IgG from different species, while protein A, tested for comparative purposes, displayed a strong specificity for human and swine IgG. Furthermore, the protein reacted with antigen specific goat IgG (specific for gamma chains of human IgG), sheep red blood cells (SRBC) sensitized with rabbit antiserum to SRBC, that is, the Fc part of rabbit IgG, and concanavalin A as well. These findings may suggest that the protein is a lectin which binds the carbohydrate moiety of the Fc part of IgG.

Animals↗
PubMed1994

Neointima formation after vascular stent implantation. Spatial and chronological distribution of smooth muscle cell proliferation and phenotypic modulation.

Intravascular stents have proved useful as angioplasty devices, but intimal hyperplasia after stent implantation remains an unsolved problem. In the present study, we analyzed the spatial and chronological distribution of proliferation and phenotypes of smooth muscle cells (SMCs) in rabbit aortas during the process of neointima formation after stent implantation (Gianturco's Z type) by immunohistochemistry for proliferating cell nuclear antigen (PCNA) and myosin heavy chain isoforms (SM1, SM2, and SMemb). Stent implantation induced regional injury in the arterial wall. Medial SMCs then began to proliferate adjacent to the injured SMCs, maximally on day 4 (PCNA index in the media: 3.9 +/- 3.4% [mean +/- SD]), and were modulated to the embryonic phenotype (SMemb-positive and SM2-negative). They migrated into the intima and proliferated most frequently on day 7 (PCNA index in the intima: 20.3 +/- 5.5%) and subsequently led to fibrocellular neointima formation at 2 weeks and later. At 1 month after implantation and later, SMC proliferation was rare, and the phenotype of intimal SMCs was gradually returning to the adult type (SMemb-negative and SM2-positive). Thus, this stent implantation model demonstrates that the regional effect on arterial wall by stenting leads to neointima formation through transient and regional proliferation and migration of SMCs and their phenotypic modulations.

Animals↗
PubMed1994

Replication of filamentous cyanobacterial plasmids, pPF1 from Phormidium foveolarum and pPB1 from Plectonema boryanum.

Single-stranded plasmid DNA of pPF1 from Phormidium foveolarum that was specifically degraded by S1 nuclease was detected by Southern hybridization. This is also the case of the homologous plasmid pPB1 from Plectonema boryanum. These observations suggest that such small cryptic plasmids as pPF1 and pPB1, both from Gram-negative and filamentous cyanobacteria, replicate by a rolling circle mechanism in their living cells.

Base Sequence↗
PubMed1994

Monitoring of hepatic venous oxygen saturation for predicting acute liver dysfunction after Fontan operations.

Acute liver dysfunction after Fontan operations may result from inadequate hepatic perfusion along with low cardiac output and high central venous pressure. We monitored hepatic venous oxygen saturation in 15 patients after Fontan operations to determine whether oxygen saturation predicts the occurrence and severity of acute liver dysfunction. We measured oxygen saturation from hepatic venous blood samples every 4 to 5 hours for at least 24 hours after the operation and used the mean hepatic venous oxygen saturation value for the first 24 hours after the operation to analyze the relationship between oxygen saturation and hepatic function. As indices of hepatic function, we measured serum alanine aminotransferase, total bilirubin, blood lactate (arterial, hepatic venous, and the difference between them), and the arterial ketone body ratio (the ratio of aceto-acetate to beta-hydroxybutyrate). For alanine aminotransferase and bilirubin, we used the maximal values during the first week in the analysis, and for blood lactate and ketone body ratio, we used the mean values for the first 24 hours after the operation. Significant broken-line regression relationship existed between mean hepatic venous oxygen saturation and hepatic function indices (alanine aminotransferase, total bilirubin, and blood lactate). The interpretation of these relationships is that hepatic indices are constant above the critical mean hepatic venous oxygen saturation values but are correlated with mean hepatic venous oxygen saturation below critical points in the range of 21% to 26%. Thus a hepatic venous oxygen saturation value below about 25% during the first 24 hours after a Fontan operation predicts the occurrence and the severity of acute liver dysfunction. We suggest that monitoring hepatic venous oxygen saturation is useful for management of critically ill patients after Fontan operations.

Adolescent↗
PubMed1994

[Ultrastructural assessment of postoperative lung injury--the effect of bronchial blood flow during cardiopulmonary bypass].

On the basis of the hypothesis that pulmonary blood flow during cardiopulmonary bypass (CPB) is related to postoperative pulmonary dysfunction, we divided following two groups in 17 patients with congenital cardiac disease; A group: bronchial blood flow (BF) during CPB < 10%, B group: BF during CPB > 25%. Lung specimens taken immediately after CPB were reviewed for ultrastructural changes using semi-quantitative grading of epithelial cell injury, endothelial cell injury, and measuring thickness of basement membrane (BMT) as the index of interstitial edema. And postoperative pulmonary function using AaDO2 were assessed. Ultrastructural grading of epithelial cell injury, BMT, and AaDO2 of A group (BP < 10) were higher than those of B group (BP > 25%). These results indicate that pulmonary blood flow during CPB somewhat may reduce pulmonary impairment for CPB.

Bronchi↗
PubMed1994

Platelet-activating factor plays an important role in reperfusion injury in myocardium. Efficacy of platelet-activating factor receptor antagonist (CV-3988) as compared with leukocyte-depleted reperfusion.

Although platelet-activating factor has been implicated in the pathogenesis of neutrophil-induced reperfusion injury, it has other mechanisms of direct deleterious hemodynamic effect. In this study we evaluated the definitive role of platelet-activating factor in myocardial reperfusion injury. Porcine hearts that underwent 60 minutes of normothermic ischemia with cardioplegia and 60 minutes of reperfusion under cardiopulmonary bypass were divided into three groups according to the methods of 15 minutes of controlled reperfusion: whole blood reperfusion group (n = 6), leukocyte-depleted reperfusion group (n = 6), and platelet-activating factor receptor antagonist (CV-3988) group (n = 6). At 60 minutes of reperfusion, the percentage of recovery of maximum slope of the pressure-volume relationship measured with intraventricular balloon, malondialdehyde value in coronary sinus blood, tissue adenosine triphosphate, and percentage of spontaneous defibrillation were evaluated. The receptor antagonist group showed significantly better recovery of maximum slope of the pressure-volume relationship than did the whole blood reperfusion group. Moreover, the receptor antagonist group showed significantly less release of malondialdehyde in the coronary sinus, higher values of adenosine triphosphate in the myocardium, and a higher percentage of spontaneous defibrillation than did the whole blood reperfusion group. On the other hand, the leukocyte-depleted reperfusion group showed no significant differences of maximum slope of the pressure-volume relationship, malondialdehyde, adenosine triphosphate, or spontaneous defibrillation as compared with the whole blood group. These results suggest that platelet-activating factor receptor antagonist attenuated severe damage in whole blood reperfusion of the myocardium as compared with leukocyte-depleted reperfusion, which also suggests that platelet-activating factor may play a more important role in myocardial reperfusion injury than do neutrophils.

Animals↗
PubMed1994

Evaluation of leukocyte-depleted terminal blood cardioplegic solution in patients undergoing elective and emergency coronary artery bypass grafting.

Leukocyte depletion at reperfusion may have a role in myocardial protection when combined with terminal cardioplegia. We applied this method in a selected group of 68 patients with coronary artery bypass grafting either for elective surgical procedures (n = 38) or emergency surgical procedures with the use of a preoperative intraaortic balloon pump (n = 30) because of developing acute myocardial infarction. Basic cold potassium crystalloid cardioplegic solution was used. During delivery of leukocyte-depleted terminal cardioplegic solution, warm arterial blood delivered from cardiopulmonary bypass was passed through a leukocyte removal filter, mixed with potassium crystalloid cardioplegic solution, and administered to the aortic root for the first 10 minutes of reperfusion. Patients were randomized into three groups for reperfusion: whole blood, terminal cardioplegic solution, and leukocyte-depleted terminal cardioplegic solution reperfusion groups. In elective coronary artery bypass grafting, no significant difference was found in the clinical data. However, in emergency coronary artery bypass grafting, the leukocyte-depleted terminal cardioplegic solution group (n = 10) showed significantly lower peak creatine kinase MB levels (leukocyte-depleted terminal cardioplegic solution versus terminal cardioplegic solution versus whole blood: 27 +/- 11, 56 +/- 13, 74 +/- 18, respectively; p < 0.05) and maximum dopamine doses required at the weaning of cardiopulmonary bypass (6.3 +/- 1.1 versus 11.2 +/- 3.3 versus 9.2 +/- 2.2; p < 0.05) than did the terminal cardioplegic solution (n = 10) and whole blood groups (n = 10). Moreover, the leukocyte-depleted terminal cardioplegic solution group showed significantly lower difference of malondialdehyde between arterial and coronary sinus blood (0.15 +/- 0.09 versus 0.36 +/- 0.06 versus 0.06 +/- 0.12 nmol/ml, p < 0.05) than did the terminal cardioplegic solution or whole blood groups. These results showed that leukocyte-depleted terminal blood cardioplegic solution may have a role in attenuating reperfusion injury in patients with critical conditions such as preoperative myocardial ischemic injury.

Adult↗
PubMed1994

[Invasive thymoma].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1994

Experimental study of the reversibility of sinusoidal capillarization.

This study investigated the reversibility of sinusoidal capillarization in fibrotic rat liver induced by thioacetamide (TAA; 200 mg/kg body weight three times a week). Six weeks later, collagen fibers and hepatic lobular disarrangement were observed on light microscopy and basement membrane formation was noted in the space of Disse. Sinusoidal endothelial fenestrations (SEFs) were decreased in size and number (defenestration), and factor VIII-related antigen was observed in the cytoplasm. We also clarified the phenotypic reversibility of the sinusoidal endothelial cells. After 4 months following discontinuation of TAA exposure, the diameters and numbers of SEFs were increased. Six months later, the basement membrane in the space of Disse disappeared (as assessed by electron microscopy) and 12 months later, factor VIII-related antigen also disappeared. These results indicate that phenotypical changes in the sinusoidal endothelial cells and sinusoidal capillarization in hepatic fibrosis may be reversed.

Animals↗
PubMed1993

Hemodynamic characterization in experimental liver cirrhosis induced by thioacetamide administration.

Systemic and splanchnic hemodynamics in experimental liver cirrhosis in rats induced by thioacetamide were evaluated by the radioactive microsphere method. Cardiac output and regional blood flow were measured in conscious and anesthetized control and cirrhotic rats. The conscious thioacetamide-treated rats had hyperdynamic circulation with an increased cardiac index (300 +/- 10 vs 258 +/- 3 ml/min/kg body weight, P < 0.001) and increased portal venous inflow compared with the controls (64.60 +/- 2.4 vs 48.39 +/- 0.88 ml/min/kg body weight, P < 0.001). Under pentobarbital anesthesia, the hyperdynamic circulation of the cirrhotic rats was maintained, with an increased cardiac index (276 +/- 7 vs 229 +/- 5 ml/min/kg body weight, P < 0.001) and increased protal venous inflow compared with the controls (72.47 +/- 3.0 vs 54.08 +/- 1.2 ml/min/kg body weight, P < 0.001). Portal pressure, portal venous resistance, and portal systemic shunting increased significantly while splanchnic arterial resistance decreased significantly in cirrhotic rats. Thioacetamide-induced cirrhosis is a useful model for the hemodynamic study of portal hypertension and remains useful in hemodynamic studies in the basal state under pentobarbital anesthesia.

Anesthesia, General↗
PubMed1993

Effect of a somatostatin analogue (SMS 201-995) on hemodynamics and glucagon secretion in cirrhotic rats.

The effects of somatostatin analogue, SMS 201-995, on systemic and splanchnic hemodynamics and glucagon secretion were investigated in control and cirrhotic rats induced by thioacetamide administration. Hemodynamics were measured using the radioactive microsphere method. Immunoreactive glucagon (IRG) was determined in the portal vein and femoral artery and the splanchnic output (OP) of IRG was calculated. In control rats, SMS 201-995 induced a decrease of 5.6% in portal venous inflow and a 25.8% decrease in OP of IRG. In cirrhotic rats, SMS 201-995 produced a 14% decrease in portal pressure, a 13.6% decrease in portal venous inflow, and a 57.8% decrease in OP of IRG. In systemic hemodynamics no significant changes were noted following SMS 201-995 administration in the control or cirrhotic rats. The ratio of cirrhotic rats to the controls in the rate of decrease in portal venous inflow was similar to that in the percentage of decrease in OP of IRG. We conclude that SMS 201-995 is useful for the treatment of portal hypertension because of its effect of reducing portal pressure with mild changes in systemic hemodynamics. We suspect that the decrease in portal venous inflow by SMS 201-995 is mainly due to a reduction in the release of glucagon, a vasodilatory gastrointestinal hormone.

Animals↗
PubMed1993

Structural organization of a cryptic plasmid, pMA1, from Microcystis aeruginosa f. aeruginosa Kützing.

The 2287-bp cryptic plasmid, pMA1, from Microcystis aeruginosa f. aeruginosa Kützing, a unicellular cyanobacterium originally derived from Kasumigaura lake, was completely sequenced and analyzed. The predicted amino acid sequence (253 residues) of an open reading frame had identities of 47%, 48%, and 53% with replication-associated proteins of Bacillus amyloliquefaciens's plasmid, pFTB14, B. subtilis BAA1's pBAA1, and B. coagulans's pBC1, respectively, when conservative amino acid substitutions were included. Such high-level identities were also shown with rep proteins and ori regions in a group of Gram-positive bacterial plasmids such as Lactococci and Staphylococci that are known to replicate via single-stranded intermediates. The pMA1 does hybridize with a plasmid, pUS1-3, derived from another unicellular cyanobacterium, Synechocystis sp. PCC 6803. Novel features of pMA1 are discussed.

Amino Acid Sequence↗
PubMed1993

[Changes in monoamine and monoamine metabolites in the nucleus accumbens and locomotor activity caused by p-chloroamphetamine: studies with intracerebral dialysis in freely moving rats].

The effect of i. p. administration of p-chloroamphetamine (PCA) (2mg/kg) on the dopamine (DA), serotonin (5-HT), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) was estimated in freely moving rats by intracerebral dialysis in the nucleus accumbens. Locomotor activity was measured simultaneously by the Animex. After PCA administration, locomotor activity increased significantly in hours 1-2. DA concentration was elevated statistically for 1-2 hours after PCA treatment. And the change of locomotor activity and DA levels were correlated. 5-HT was slightly elevated for 1-2 hours after PCA treatment, although this was not statistical significance through the whole experimental period. These results suggest that an increase in locomotor activity induced by PCA may be explained by activation of the dopaminergic systems in the nucleus accumbens. DOPAC, HVA and 5-HIAA were suppressed significantly during 1-6th. These results suggest that suppression of DOPAC, HVA and 5-HIAA induced by PCA may be explained by PCA's pharmacological effect such as inhibition of monoamineoxidase.

Animals↗