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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 523 records · Page 29Linked to original sources
PubMed1985

Synchronized diastolic coronary venous retroperfusion: results of a preclinical safety and efficacy study.

The safety and efficacy of a new clinical synchronized diastolic retroperfusion mechanical pump and autoinflatable balloon catheter was studied in 10 dogs during and after 6 hours of left anterior descending coronary artery occlusion. Eight other dogs served as the untreated control group. Infarct size measured by triphenyltetrazolium chloride, and expressed as a percent of area at risk, was significantly reduced by retroperfusion treatment (19 +/- 18 versus 58 +/- 36, p less than 0.01). Morphologic examination of the coronary sinus and cardiac veins did not demonstrate evidence of damage from synchronized retroperfusion. There was also no evidence of excess myocardial edema in either the jeopardized ischemic or normally perfused zones. There was no evidence of significant red cell hemolysis or platelet destruction from the treatment. Thus, it appears that synchronized diastolic retroperfusion is a safe and effective treatment of acute myocardial ischemia in experimental animals and warrants clinical testing.

Animals↗
PubMed1985

Comparative echocardiographic study of recovery of diastolic versus systolic function after brief periods of coronary occlusion: differential effects of intravenous nifedipine administered before and during occlusion.

The effect of intravenous nifedipine (5 micrograms/kg) on the recovery of myocardial function after occlusion of the left anterior descending coronary artery was studied in 18 closed chest dogs. Using computer-aided analysis of two-dimensional echocardiograms, systolic and diastolic function of ischemic segments in low papillary left ventricular cross sections were characterized, respectively, as holosystolic fractional area change and early diastolic velocity of luminal area change. The time required for systolic function to return to preocclusion values after a 1 minute untreated control occlusion (n = 12) was 5 to 10 minutes, and after a 2 minute occlusion (n = 6) it was 20 to 30 minutes. When nifedipine was administered during the occlusion, recovery after a 2 minute occlusion was accelerated slightly to 10 to 15 minutes. Recovery times of early diastolic function were substantially longer, and nifedipine effects were more pronounced. After a 1 or 2 minute control coronary occlusion, 60 to 75 minutes or 90 to 105 minutes were needed to return early diastolic function to normal levels. Nifedipine administered during a 1 or 2 minute coronary occlusion improved these recovery times to 10 to 15 minutes. When the dogs were treated with intravenous nifedipine before coronary occlusion, recovery after 1 or 2 minutes of acute ischemia was apparent as early as 2 minutes after reperfusion. Thus, intravenous nifedipine accelerates the recovery of myocardial function after brief periods of ischemia, and when administered before coronary occlusion, it assures very prompt recovery of function.

Animals↗
PubMed1985

Synchronized coronary venous retroperfusion: prompt improvement of left ventricular function in experimental myocardial ischemia.

The effect of synchronized coronary venous retroperfusion of arterial blood on cardiac function after experimental coronary occlusion was examined by two-dimensional echocardiography. In 18 closed chest anesthetized dogs, the proximal left anterior descending coronary artery was occluded for 6 hours with an intracoronary balloon catheter. Eight of these animals served as untreated controls. Ten were treated with synchronized retroperfusion initiated 30 minutes after occlusion, and treatment was interrupted for 5 minutes at 1 hour after occlusion for study of the rapidity of retroperfusion response. Quantitative echographic analysis yielded global ejection fraction and regional indexes of contraction in a low left ventricular short-axis section, including segmental systolic area change, systolic wall thickening and end-diastolic wall thickness. At 6 hours after occlusion, ejection fraction had decreased from 50.7 +/- 4.9% to 28.1 +/- 7.7% (mean +/- standard deviation) in control dogs, but was significantly (p less than 0.01) less depressed in treated dogs (from 55.9 +/- 5.2 to 41.8 +/- 9.3%). The ischemic zone fractional area change at 30 minutes of occlusion exhibited a marked depression in both groups, after which the dysfunction persisted in the control dogs, but was largely reversed with retroperfusion from 6.0 +/- 6.5 to 35.9 +/- 15.9% at 6 hours of occlusion (p less than 0.01). Brief interruption of retroperfusion 1 hour after occlusion reduced ischemic zone fractional area change from 33.0 +/- 14.9 to 12.2 +/- 9.5% (p less than 0.01). This depression was promptly reversed to 33.6 +/- 12.2% when retroperfusion was resumed. Segmental wall thickening followed a similar trend.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Stereochemical studies of a selenium-containing hydrogenase from Methanococcus vannielii: determination of the absolute configuration of C-5 chirally labeled dihydro-8-hydroxy-5-deazaflavin cofactor.

Reduction of 7,8-didemethyl-8-hydroxy-[5-2H]-5-deazariboflavin by the selenium-containing hydrogenase from Methanococcus vannielii gave a C-5 chirally labeled 1,5-dihydro derivative. The absolute configuration of the chiral label was shown to be (R) by comparison of the chemically degraded product with authentic samples of known absolute configurations. Therefore, the steric course of the enzymic reactions involving the 8-hydroxy-5-deazaflavin cofactor can be defined as follows: (a) reduction occurs on the si face of the 5-deazaflavin molecule; (b) oxidation proceeds by the abstraction of the pro-S hydrogen at C-5 of the 1,5-dihydro-5-deazaflavin. Thus, the selenium-containing hydrogenase and 8-hydroxy-5-deazaflavin-dependent NADP+ reductase from M. vannielii are si face specific.

Euryarchaeota↗
PubMed1985

Bile duct necrosis: complication of transcatheter hepatic arterial embolization.

Bile duct necrosis because of transcatheter hepatic arterial embolization (THAE) in two patients with hepatocellular carcinoma is reported. Preoperative THAE was performed on 29 patients, and bile duct necrosis was experienced by two of the 29 (7%). In these two patients, gelatin (Gelfoam) powder was used as the embolus. Among the 24 whose embolus was clear, four were embolized with gelatin powder. Therefore, incidence of bile duct necrosis after THAE with gelatin powder was 50%. Because of the hazards of severe complications such as bile duct necrosis, we conclude that gelatin powder should not be used except for the THAE of no more than one segment of the liver.

Bile Ducts↗
PubMed1985

Spontaneous arthritis in nude rats of Rowett hooded strain.

Spontaneous arthritis was found in 19 of 55 Rowett hooded strain rats with rnu gene. Most cases were in the male rnu/rnu (15/19) but a few occurred in the male rnu/+ (3/10) and female rnu/rnu (1/8). The lesions were first noted as reddened swelling due to exudative inflammation of periarticular soft tissues including synovial membranes in the tarsal and/or carpal joints. Most of the affected animals cured leaving slight induration but in a few male rnu/rnu ankylosis with pannus formation and exostosis developed. No sign of mycoplasmal or bacterial infection was noticed in the colony.

Age Factors↗
PubMed1985

Genome type analysis of adenovirus type 4 isolates, recently obtained from clinically different syndromes in some areas in Japan.

DNA cleavage analyses with EcoRI, HindIII and BamHI were carried out to investigate genome types of recent Ad 4 isolates obtained from acute respiratory disease (8 strains), and ocular disease (11 strains) in Japan. DNA cleavage patterns of all 19 isolates studied were identical regardless of whether they were recovered from respiratory tract or conjunctiva, but were distinct from that of the prototype strain.

Adenoviridae Infections↗
PubMed1985

Ultrasonically guided subsegmentectomy.

A new operative procedure for systematic subsegmentectomy guided by ultrasound has been described. This operation consists of operative sonography, ultrasonically guided puncture and injection of dye and hemihepatic blood occlusion. Systematic subsegmentectomy was performed upon 57 patients without operative mortality. The cumulative one year survival rate of 35 patients with hepatocellular carcinoma who underwent operation at our hospital was 80.3 per cent. The two and three year survival rates were 63.3 and 52.6 per cent, respectively.

Carcinoma, Hepatocellular↗
PubMed1985

Pharmacokinetic study of a human recombinant interferon (Re-IFN-alpha A) in cynomolgus monkeys by 2'-5' oligoadenylate synthetase assay.

We evaluated 2'-5'Oligoadenylate (2-5 A) synthetase assay for pharmacokinetic study of human interferon (IFN) in cynomolgus monkeys. The enzyme was induced in primary cultures of cynomolgus monkey kidney (PMK) cells as well as in FL cells in response to human recombinant IFN-alpha A treatment. The enzyme activity increased with IFN dose and, in parallel with the enzyme elevation, developed the antiviral state of the cells. The enzyme activity induced in the peripheral blood lymphocytes peaked at 6 to 12 hr after iv or im administration. The peak level of the enzyme activity depended on the IFN concentration of the blood and the activity rapidly decreased as serum IFN was cleared from the blood. These results indicate that human recombinant IFN-alpha A induces 2-5 A synthetase in monkey cells both in vitro and in vivo, and that the enzyme assay can be used to quantitatively monitor the host response after IFN administration.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

[Experimental study of brain lesions after combined coaxial exposure to high-peaked pulse wave form CO2 and Nd: YAG lasers on the brain].

UNLABELLED: The CO2 laser is useful for cutting and vaporization but not for coagulation and hemostasis. On the contrary, YAG laser is effective for coagulation and hemostasis but not for cutting. The purpose of this study is to examine the effect of the exposure of combined, coaxial CO2 and YAG laser on the animal brain to supplement the advantages and draw-backs of each other. To compare these results, each of non-combined pulse wave form CO2 and YAG lasers was employed separately. MATERIALS AND METHODS: The lasers in this study were pulse wave form CO2 and YAG lasers, employed separately or simultaneously using 130 YZ of Nihon Infrared Industries Company. Japanese white rabbits were anesthetized with pentobarbital. Fronto-parietal burr holes were made, the dura was removed and then Evans blue solution was injected intravenously. The lasers were employed to the cerebral cortex without great vessels using a micromanipulator attached to the operative microscope with a distance of 30 cm. The spot size was 700 mu for CO2 laser and 1200 mu for YAG laser. The first experiment was to see the effect of nine combinations of simultaneous coaxial CO2 of 2, 4 and 8 watts and YAG lasers of 10, 20 and 40 watts, 1 sec on the brain. In the second experiment, also combining two lasers, the exposure time of YAG laser was elongated from 1 or 2 seconds into 2 or 4 seconds and the arrangement of powers was the same as that of the first experiment. The lesions were thus made in 18 different conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Immunological responses to monoassociated Bifidobacterium longum and their relation to prevention of bacterial invasion.

After monoassociation of Bifidobacterium longum with germ-free BALB/c mice (nu/+, heterozygous to nu gene), B. longum was recovered (10(2)-10(4) viable units per organ) from the mesenteric lymph nodes, liver and kidneys for 2 weeks post intragastric inoculation, but not after 4 weeks and later. Cessation of bacterial translocation was not observed in monoassociated nude (nu/nu) mice. Anti-B. longum IgA antibody was detected by ELISA using B. longum cell wall antigen in bile from Week 1 and in ileac wall extract from Week 8 post-association in both nu/+ and nu/nu mice. Total IgA levels in bile, ileac wall extract and caecal contents were also elevated in both mice after monoassociation. Cell-mediated immunity measured by the footpad test and macrophage migration inhibition test using B. longum protein fraction was detected in nu/+ mice in Week 4 and later, but not in nu/nu mice. Nu/nu mice reconstituted 4 weeks prior to monoassociation with lymphocytes from flora bearing nu/+ mice developed delayed footpad reactivity and bacterial translocation stopped after 4 weeks. Cell-mediated immunity rather than IgA antibody correlated well with the cessation of translocation.

Actinomycetales Infections↗