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H Tadokoro

Publications and source records attributed to H Tadokoro.

At least 19 recordsLinked to original sources
PubMed1991

Low-frictional catheter materials by photo-induced graft polymerization.

To develop low-frictional catheters, photo-induced graft polymerization of N,N-dimethylacrylamide (DMAA) was performed on to films and tubes of ethylene-vinyl acetate copolymer (EVA) and poly(vinyl chloride) (PVC). Their surfaces became very slippery, when the materials were preirradiated with UV from a low-pressure mercury lamp, followed by graft polymerization with DMAA in the presence of small amount of riboflavin without degassing. Although no significant difference was observed in surface lubrication between the EVA film and the tube, the latter required an additional procedure for the graft polymerization, that is, removal of air trapped inside the tube. The surfaces of EVA and PVC tubes grafted with DMAA were found to exhibit frictional forces around 0.5 N against a PVC and a silicone surface under wet conditions, whereas the frictional force of the ungrafted tubes against the same substrates was 10 and 20 N for PVC and EVA, respectively.

Catheterization↗
PubMed1991

Aquatic toxicity testing for multicomponent compounds with special reference to preparation of test solution.

An adequate method of determining the toxicity of a compound consisting of multiple components, such as creosote, coal tar, and coal tar pitch, was studied for different test solution preparation methods, i.e., direct dosing without filtration, diluting the stock solution of saturated concentration, and dispersing with acetone. Killifish, Oryzias latipes, as a freshwater fish; red sea bream, Pagrus major, as a saltwater fish; and daphnia, Daphnia magna, as a representative crustacean, were used for testing. The chemical analysis of each preparation of test solution with gas chromatography revealed an entirely different profile of the components. The highest toxicity was obtained with preparation by acetone dispersion. That was followed by the preparations with direct dosing method and with the method of dilution of saturated concentration stock solution. Considering the results obtained, the direct dosing method with a suitable settling time may provide useful information enabling extrapolation of the test results to the natural environment for complex multicomponent compounds.

Acetone↗
PubMed1991

Pharmacokinetic analysis of coronary venous retroinfusion: a comparison with anterograde coronary artery drug administration using metoprolol as a tracer.

Plasma and myocardial tissue concentrations of metoprolol were studied in ischemic and nonischemic areas of 22 pigs after 90 (n = 19) and 16 (n = 3) min of left anterior descending coronary artery occlusion. Group A (n = 6) received simultaneous intravenous metoprolol (0.2 mg/kg body weight) and tritium-labeled (3H)-metoprolol (0.2 mg/kg) retrogradely into the coronary vein. In group B (n = 5), metoprolol and 3H-metoprolol were administered in the same way, but at half the volume to study the influence of derived coronary venous pressure on the myocardial concentration of drug. In group C (n = 3), metoprolol was given retrogradely and saline solution was infused into the left anterior descending artery before induced death to wash out metoprolol from the coronary veins. To rule out a possible influence of the development of myocardial necrosis on drug distribution, metoprolol was retroinfused after 1 min of arterial occlusion in three pigs (group D). In group E (n = 5), metoprolol (0.2 mg/kg) was infused anterogradely into the left anterior descending artery. Peak plasma concentration was significantly higher after intravenous infusion of metoprolol (1,188 +/- 503 nmol/liter) than after coronary venous infusion (417 +/- 155 nmol/liter; p less than 0.001). In groups A and B, the nonischemic myocardial concentration of metoprolol was 250 to 300 pmol/g, whether the drug was infused intravenously or into the coronary vein. Coronary venous retroinfusion, however, resulted in a substantial accumulation of metoprolol in the ischemic myocardium. In group A pigs, subendocardial myocardial concentration was 16,800 +/- 7,774, mid-myocardial 39,590 +/- 18,043 and subepicardial 57,143 +/- 29,030 pmol/g (mean +/- SE). The ischemic myocardial concentration in pigs from group B was somewhat less pronounced, probably secondary to a lower coronary venous pressure (15 +/- 3 mm Hg) with the lower volume of infusion (6.1 +/- 0.3 ml) in group B compared with 32 +/- 5 mm Hg with a 14 +/- 1 ml infusion in group A. Coronary artery anterograde administration resulted in myocardial ischemic and nonischemic zone drug concentrations similar to those observed after retroinfusion into the coronary vein. With both modes of administration, there was a transmyocardial gradient from a somewhat lower drug concentration in the subendocardium, toward an increasing level in the mid-myocardium, to the highest concentration in the subepicardial zone of the ischemic myocardium. Coronary venous retroinfusion resulted in pronounced drug accumulation in the ischemic myocardium. The derived coronary venous pressure during infusion influenced the concentration of drug.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Retrograde coronary venous administration of recombinant tissue-type plasminogen activator: a unique and effective approach to coronary artery thrombolysis.

Recent studies of interventional therapy by way of the coronary venous system have demonstrated that it can protect acutely ischemic myocardium. To evaluate the efficacy of coronary venous retroinfusion compared with systemic intravenous administration of recombinant tissue-type plasminogen activator (rt-PA), 14 dogs were studied with a copper coil-induced thrombus in the left anterior descending coronary artery. The rt-PA (24,000 fluorescence units/kg) was administered continuously, either intravenously (n = 8) or retrogradely (n = 6), for 30 min beginning 60 min after coronary occlusion. Thrombolysis was determined by repetitive coronary angiography. All dogs were killed 3 h after termination of rt-PA infusion and infarct size was measured by the triphenyltetrazolium chloride staining technique. Complete thrombolysis occurred in five of the six dogs in the retroinfusion group and four of the eight dogs in the systemic intravenous infusion group. Partial lysis was achieved in two dogs treated by intravenous infusion. Lysis did not occur in one dog treated with retroinfusion and in two dogs treated with intravenous infusion. Time to thrombolysis was 13.4 +/- 2.3 min in the retroinfusion group versus 27.8 +/- 4.8 min in the intravenous group (p less than 0.001). Myocardial functional recovery in the ischemic zone measured by two-dimensional echocardiography 60 min after reperfusion was significant only in the retroinfusion group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Coronary venous retroinfusion of deferoxamine reduces infarct size in pigs.

The efficacy of coronary venous retroinfusion of the iron chelator deferoxamine was studied in 24 pentobarbital-anesthetized open chest pigs with a 60 min occlusion of the left anterior descending coronary artery followed by 3 h of reperfusion. Eight retrogradely treated pigs were given 10 mg/kg body weight of deferoxamine by way of the anterior interventricular vein and eight systemically treated pigs received the same doses of deferoxamine intravenously. Drug infusions lasted for 5 min, beginning 15 min before reperfusion. Eight control pigs received systemic intravenous saline solution. Myocardial area at risk and necrotic area were assessed by the monastral blue dye and the triphenyltetrazolium chloride staining method, respectively. There were no significant differences in hemodynamics or regional myocardial function (sonomicrometry) among the groups. Infarct size expressed as percent of risk area was 73.9 +/- 13.5% in the control group, 70.6 +/- 16.4% in the systemically treated group and 48.5 +/- 21.4% (p less than 0.05) in the retrogradely treated group. In conclusion, deferoxamine significantly reduced infarct size after coronary occlusion only when given regionally by way of the coronary vein. Because there was no significant hemodynamic effect caused by deferoxamine infusion, it is suggested that this drug prevents postischemic reperfusion injury by a direct cardioprotective effect.

Animals↗
PubMed1991

Beneficial effects of coronary venous retroinfusion but not left atrial administration of superoxide dismutase on myocardial necrosis in pigs.

The efficacy of coronary venous versus left atrial administration of superoxide dismutase was studied in 24 open chest pigs which had 60 min of left anterior descending coronary artery occlusion followed by 3 h reperfusion. The pigs were randomly assigned to three treatment protocols: group A (n = 8) superoxide dismutase (5 mg kg-1) was infused into the great cardiac vein for 30 min beginning 15 min before reperfusion; group B (n = 8) superoxide dismutase (5 mg kg-1) was infused into the left atrium in a similar manner to group A; group C (n = 8) bovine serum albumin (5 mg kg-1) was infused into the great cardiac vein in the same manner as group A. Infarct size, expressed as percent of area at risk, was significantly smaller in group A (28.2 +/- 13.0%) than groups B (58.7 +/- 8.3%) and C (61.6 +/- 7.2%) (P less than 0.05). The results indicate that retroinfusion of superoxide dismutase into the great cardiac vein before reperfusion may be an effective treatment for the prevention of reperfusion injury, even in the absence of a well developed coronary collateral circulation. Antegrade (left atrial) administration of the same amount of superoxide dismutase did not decrease infarct size in pigs. The most likely explanation for this difference in efficacy is that drug delivery with left atrial administration is dependent on antegrade flow with reperfusion which is less reliable and less efficient than coronary venous retroinfusion. The latter provides a predictably high concentration of superoxide dismutase to the jeopardized myocardium during the period of ischaemia before reperfusion.

Animals↗
PubMed1991

Differences in infarct size with lidocaine as compared with bretylium tosylate in acute myocardial ischemia and reperfusion in pigs.

The effects of the antiarrhythmic drugs lidocaine and bretylium tosylate on myocardial necrosis were studied in anesthetized pigs subjected to 60-min coronary occlusion followed by 3-h reperfusion. Group A (n = 7) received lidocaine (average dose +/- SD = 1,828 +/- 515 mg) before and during coronary occlusion and after reperfusion; the other series (group B, n = 7) received bretylium tosylate (3,457 +/- 1,323 mg). Infarct size was 16.3 +/- 14.7% in the lidocaine group as compared with 68.6 +/- 12.6% (p less than 0.01) in the bretylium group. In vitro release of superoxide anion from porcine granulocytes was studied using the lucigenin-dependent chemiluminescence technique. Lidocaine significantly reduced the peak chemiluminescence response to zymosan from 3.34 +/- 0.44 without lidocaine to 2.23 +/- 0.46 (p less than 0.01) and 1.06 +/- 0.17 mV (p less than 0.001), with lidocaine concentrations of 20 and 200 micrograms/ml, respectively. Bretylium had no effect on the chemiluminescence response. Adherence of porcine granulocytes to plastic was also reduced from 332 +/- 32 cells/mm2 (no lidocaine) to 247 +/- 35 and 206 +/- 26 cells/mm2 with lidocaine concentrations of 20 and 200 micrograms/ml, respectively (p less than 0.001). Bretylium had no significant effect. Eight additional bretylium-treated pigs received either rabbit antiporcine granulocyte serum (group C, n = 4) to reduce circulating granulocytes or nonimmune serum (group D, n = 4). Infract size in the granulocyte-depleted pigs was 26.6 +/- 5.6% as compared with 51.4 +/- 5.5% in pigs that received nonimmune serum (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

More rapid thrombolysis with coronary venous retroinfusion of streptokinase compared with intravenous administration. An experimental study in canines.

The efficacy of coronary venous retroinfusion vs intravenous administration of streptokinase was compared in 20 closed chest dogs with copper coil induced thrombosis of the left anterior descending coronary artery. Streptokinase was continuously infused for 60 min (100 IU kg-1 min-1) starting 60 min after coronary artery occlusion. Time to clot lysis was determined by coronary angiography performed at 5 min intervals. Complete lysis occurred in eight out of 10 dogs receiving intravenous streptokinase and in all 10 dogs in the coronary venous group. Time to thrombolysis was significantly shorter with coronary venous retroinfusion (23 +/- 8 min) than after systemic infusion (62 +/- 26 min; P less than 0.001). Recovery of ischaemic zone left ventricular systolic function, studied by two-dimensional echocardiography, was significantly better in the animals that received retrograde streptokinase than in the group that received intravenous streptokinase (17 +/- 12% vs -2 +/- 16%; P less than 0.05). Myocardial necrosis expressed as a percentage of the risk area was 8 +/- 12% after retroinfusion of streptokinase compared with 32 +/- 25% (P less than 0.005) after intravenous administration. In conclusion, coronary venous administration of streptokinase was more effective than intravenous therapy as determined by more rapid clot lysis which resulted in improved functional recovery of the ischaemic myocardium and a significant reduction in myocardial necrosis.

Animals↗
PubMed1990

Pronounced accumulation of metoprolol in ischemic myocardium after coronary venous retroinfusion.

The myocardial availability of the beta 1-selective blocker metoprolol was compared following standard intravenous (i.v.) administration and after coronary venous retroinfusion. Thirteen open-chest farm pigs were subjected to 90-min occlusion of the left anterior descending coronary artery. In six of these pigs, metoprolol was administered as an i.v. injection while 7 pigs received the drug retrogradely into the coronary vein. The time of administration was 5 min. In both groups, metoprolol was administered after 30 min of coronary artery occlusion. Metoprolol did not influence heart rate (HR) or blood pressure (BP) whether administered i.v. or into the coronary vein. At the end of administration, plasma metoprolol was significantly higher when administered i.v. (2,955 +/- 543 nmol/L) than after coronary venous infusion (1,213 +/- 464 nmol/L; p less than 0.05). At 30 and 60 min after injection, plasma metoprolol did not differ significantly between the two groups. Myocardial tissue concentration of metoprolol in nonischemic myocardium was approximately 480 pmol/g for both groups and similar in the subendocardial, midmyocardial, and subepicardial layers of the myocardium. After i.v. administration, myocardial Metoprolol concentration in the ischemic zone was less than that in the nonischemic zone, averaging 150-300 pmol/g tissue. In contrast, coronary venous retroinfusion of metoprolol resulted in a substantial accumulation of the drug in the ischemic zone, as exemplified by a subendocardial concentration of 2,002 +/- 689; a midmyocardial concentration of 26,643 +/- 8,813 and a subepicardial concentration of 98,571 +/- 58,930 pmol/g, respectively (mean +/- SE). Coronary venous retroinfusion of metoprolol resulted in a pronounced accumulation of drug in the ischemic myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Overestimation of myocardial infarct size by histologic measurement in a model of occlusion followed by reperfusion.

We studied 32 transverse left ventricular slices of myocardium from 16 pigs after 45 to 100 minutes of coronary artery occlusion followed by 180 minutes of reperfusion. Infarct area for each slice was determined as follows: (1) grossly, by triphenyl tetrazolium chloride staining of each slice, and (2) microscopically, by complete histologic sectioning of the triphenyl tetrazolium chloride-stained surface of each slice. Planimetry of necrotic and nonnecrotic areas was performed from tracings and photographs of triphenyl tetrazolium chloride-stained slices and from actual histologic sections. When triphenyl tetrazolium chloride and histologic measurements were compared, necrotic tissue area had decreased 11.4% +/- 15.0% (2.59 +/- 1.04 vs 2.09 +/- 0.86 cm2). Nonnecrotic tissue area decreased 20.6% +/- 24.0% (8.31 +/- 3.79 vs 5.16 +/- 2.73 cm2). In this model of ischemia followed by reperfusion, with fixation and processing, viable tissue shrank almost twice as much as necrotic tissue. This differential shrinkage introduces an error resulting in overestimation of infarct size by histologic quantitation.

Animals↗
PubMed1990

[Ileocolic intussusception in a recurrent non-Hodgkin's lymphoma; report of a case].

The adult intussusception is rare. Here, we describe a case of an adult patient with ileocolic intussusception secondary to a recurrent lymphoma of the terminal ileum. The patient was a 42-year-old female, who had a history of the subtotal gastrectomy because of the primary gastric lymphoma. Eight months after the operation, she had a relapse in the abdomen and received the combination chemotherapy. She acquired the complete remission, but six months after the completion of the chemotherapy, she suffered from the right lower abdominal pain and diarrhea. Physical examination revealed a soft mass with tenderness in the right iliac fossa. Barium studies and abdominal computed tomography showed an ileocolic intussusception. At laparotomy, a 4.5 cm polypoid tumor was found in the terminal ileum and it passed through the ileocaecal valve to form an intussusception. Histologic examination disclosed the follicular lymphoma of medium-sized cell type. So far as we are aware, this is the first report of an adult patient with intussusception secondary to a lymphoma in Japan.

Adult↗
PubMed1989

Beneficial effects of coronary venous retroinfusion of superoxide dismutase and catalase on reperfusion arrhythmias, myocardial function, and infarct size in dogs.

The efficacy of coronary venous retroinfusion of superoxide dismutase and catalase was studied in anesthetized closed chest dogs with 90-min left anterior descending coronary artery (LAD) occlusion followed by 3-h reperfusion. In group A, superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) were administered by a 30-min continuous right atrial infusion beginning 15 min before reperfusion and supplemented by a bolus injection of superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) through the great cardiac vein immediately before reperfusion. The treatment in group B was similar to that in group A, except that the bolus injection was into the right atrium. In the control group (group C), saline was administered in the same manner as in group A. Infarct size, expressed as a percentage of the risk area, was significantly smaller in group A (11.3 +/- 8.9%) than in groups B (31.3 +/- 21.1%) and C (43.0 +/- 16.9%; p less than 0.05). Regional function of the ischemic zone measured by two-dimensional echocardiography exhibited significantly (p less than 0.05) greater recovery after 3-h reperfusion in group A (30.3 +/- 8.4%) versus groups B (12.5 +/- 13.7%) and C (12.1 +/- 11.7%). Moreover, there were significantly fewer postreperfusion ventricular arrhythmias in group A as compared with groups B and C. The results of this study indicate that coronary venous retroinfusion is an effective method for delivery of superoxide dismutase and catalase.

Animals↗
PubMed1989

[An undifferentiated carcinoma of the stomach--a report of 2 cases].

Two cases of an undifferentiated carcinoma of the stomach have been investigated by conventional histologic, immunohistochemical, and ultrastructural methods. The patients were a 73-year-old man and 65-year-old man. A postoperative histological examination of the resected stomach of each patient disclosed large areas of an undifferentiated carcinoma which were relatively well demarcated from areas of the adenocarcinoma. In the undifferentiated carcinomatous areas, the reticulin fiber stain was epithelial in pattern, and mucin staining proved negative. Similarly both Grimelius and Fontana-Masson staining also negative. In like manner immunostains using cytokeratin , vimentin , IgG, IgA, s-100 protein, and NSE were all negative, and an electron microscopic study showed no neurosecretory granules or mucin secretory granules. Based on these findings, the diagnosis of either a malignant lymphoma or small cell anaplastic carcinoma could be excluded, and thus an undifferentiated carcinoma was the determination.

Adenocarcinoma↗
PubMed1986

Ampicillin concentrations in human serum and periodontal membrane following a single oral administration of bacampicillin.

Ampicillin concentrations in human serum and periodontal membrane after a single oral administration of bacampicillin (500 mg) were assayed by the agar diffusion (paper disc) method. The peak times of serum and periodontal membrane were nearly identical, being approx. 90 min after administration. The peak concentrations of serum and periodontal membrane were 12.81 micrograms/ml and 6.97 micrograms/g, respectively. The concentration ratio of periodontal membrane to serum at the peak time was 0.56.

Adult↗