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Th. LAVERGNE L. PRUNIER L. CUIZE P. BRUNEVAL D. VON EUW J-Y. LE HEUZEY P. PERONNEAU 《Pacing and clinical electrophysiology : PACE》1989,12(1):177-186
Closed chest ablative technique that avoid barotrauma would be attractive for ablation at thin walled cardiac structures, such as the atrial free wall or coronary sinus. Transcatheter radiofrequency (RF) currents produce tissue necrosis the size of which is dependent on the contact between the tissue and the electrode. In order to assess the effects of transvenous RF ablation of atrial free wall using a suction electrode catheter, we delivered in ten dogs, one single unmodulated RF pulse 1.2 MHz, in a unipolar mode, through the distal electrode of a lumen catheter (USCI 8F) (USCI, Billerica, MA, USA) located in the right appendage. During the pulse an 80 KPa vacuum depression was applied to the lumen of the catheter. Each pulse had a 10 seconds duration and the mean delivered power was 4.3 ± 1.4 W. Aortic pressure and electrocardiogram were monitored during the procedure. A right airial electrophysiological study was performed at the ablated site, at control, after suction application and after RF pulse delivery. The animals were sacrificed after 14 or 21 days. Atrial pacing threshold values decreased after suction application in comparison to control values after the pulse (0.42 ± 0.06 vs 0.60 ± 0.23 mA, P < 0.05) but increased after the pulse delivery (2.60 ± 1.85 mA, P < 0.01). In contrast, the atrial effective refractory period did not significantly change after suction, nor after RF pulse delivery. Aortic pressure remained unchanged throughout the procedure. Complex arrhythmias were not observed during or after RF pulse delivery. One dog died suddenly at the first day after ablation, but this death was most probably unrelated to RF ablation. Anatomic lesions had a length of 8.8 ± 3.3 mm, a width of 4.6 ± 2.5 mm and a depth of 3.6 ± 1.1 mm. They were transmural in nine of the ten dogs but without atrial wall perforation in any case. Lesions suggesting tissue volatilization were present in four dogs. These results demonstrate that low energy RF currents delivered with a suction electrode catheter can produce transmural necrosis of free wall, without risk of perforation. Such ablative technique would be of interest for ablation of right sided accessory pathways or atrial ectopic foci. Further experimental data are required in order to define the optimal energy level required to avoid tissue volatilization. 相似文献
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HÅKAN MÖRNSTAD LARS VON KNORRING LENA FORSGREN SONJA HOLMGREN 《European journal of oral sciences》1986,94(5):461-470
Abstract – In a double-blind, controlled, cross-over trial on 10 healthy volunteers, the effects of daily doses of maprotiline (75 mg) and zimelidine (100 mg) over a 14-day period were tested on saliva secretion rate and saliva composition. Based on current knowledge of salivary gland physiology and the difference in specificity between the two drugs, differences in salivary gland response could be expected. Since both drugs have anticholinergic effects which influence saliva secretion rate, the measured component concentrations had to be recalculated with regard to dependencies of secretion rate. Maprotiline, but not zimelidine, caused strong inhibition of secretion rate and accommodation ability. Maprotiline consistently caused around 50% increases in concentrations of the following saliva components: protein, amylase, fucose, hexose, sialic acid and potassium. The effects of zimelidine were less pronounced and resulted in initial increases of most organic components. 14 and 18 h after the intake of the drug these increases had disappeared and some of the components instead showed decreased concentrations. The results are consistent with current theories about facilitated serotoninergic and noradrenergic transmissions during treatment with antidepressants. 相似文献
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Fibronectin in synovial fluid and tissue in rheumatoid arthritis 总被引:10,自引:0,他引:10
TAPIO VARTIO ANTTI VAHERI ROBERT VON ESSEN HEIKKI ISOMÄKI SVANTE STENMAN 《European journal of clinical investigation》1981,11(3):207-212
Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in rheumatoid arthritis synovial fluid was immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from rheumatoid synovial fluid by affinity chromatography on gelatin--Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS--polyacrylamide gel electrophoresis. In fifty-one patients with rheumatoid arthritis and related diseases fibronectin concentrations is synovial fluid were 445 +/- 103 micrograms/ml (mean +/- SD) and within normal range, 335 +/- 52 micrograms/ml, in plasma. Immunofluorescence staining showed a prominent increase of fibronectin in the proliferating synovial connective tissue in rheumatoid arthritis as compared to normal synovial membrane. The results suggest an increased local production of fibronectin in rheumatoid synovial tissue. 相似文献
58.
Infusible platelet membrane microvesicles: a potential transfusion substitute for platelets 总被引:8,自引:0,他引:8
FC Chao ; BK Kim ; AM Houranieh ; FH Liang ; MW Konrad ; SN Swisher ; JL Tullis 《Transfusion》1996,36(6):536-542
BACKGROUND: Several substitutes for intact, viable platelets have been used for transfusion, both to people and in animal models, with varied success. Infusible platelet membrane (IPM) is prepared from human platelets. IPM retains the glycoprotein (GP)lb receptor and has platelet factor 3 activity (procoagulant activity). However, factor V, serotonin, a cytoplasmic marker enzyme (purine nucleotide phosphorylase), GPIIb/IIIa complex, and HLA class I and II antigens are all absent in IPM. STUDY DESIGN AND METHODS: IPM is prepared from outdated platelets. The platelets were disrupted by freezing and thawing; they were washed and heated to inactivate possible viral contaminants, and then the sonicated membrane microvesicle fraction was separated and lyophilized. The hemostatic activity of IPM was measured by its ability to reduce the prolonged bleeding time in thrombocytopenic rabbits. RESULTS: Administration of IPM at a dose of 2 mg per kg results in a substantial reduction in the bleeding time. In a series of 23 experiments, a median preinjection bleeding time of 15 minutes was reduced to 6 minutes within 4 hours after IPM administration. Administration of IPM did show a mild enhancement in the thrombogenicity index, as measured in the Wessler rabbit model. This enhancement is, however, not significant, as a thrombogenicity index value of up to 0.6 is clinically acceptable. CONCLUSION: IPM may have clinical potential as a substitute for platelets in the treatment of bleeding due to thrombocytopenia. 相似文献
59.
Exercise Induced Sympathetic Influences Do Not Change Interatrial Conduction Times in VDD and DDD Pacing 总被引:1,自引:0,他引:1
BRUNO ISMER GEORG H. VON KNORRE WOLFGANG VOSS WERNER GRILLE GEORG KLENKE KAMESH PULYA WALTER KOGLEK ANTON SUNTINGER HEIDRON LUESSOW 《Pacing and clinical electrophysiology : PACE》1996,19(11):1786-1790
Using telemetry, right atrial electrogram (RA), and marker channel of atrial sense events (MA ) in combination with the left atrial electrogram (LA), recorded by a filtered bipolar esophageal lead, interatrial conduction during submaximal exercise and at rest was examined in 46 DDD pacemaker patients. The RA-LA and MA -LA conduction times measured in the presence of atrial sensing (VDD) as well as the conduction time SA -LA from atrial stimulus (SA ) to LA, determined during atrial pacing (DDD) were found to be individual constants independent of exercise induced sympathetic influences. Thus, having determined an optima! mechanical interval (LA-LV)mech/opt from left atrium to ventricle by other methods, the optimal AV delay for DDD as well as for VDD operation can be calculated by the sum of the appropriate interatrial conduction time (SA -LA, respectively MA -LA) and the (LA-LV)mech/opt interval. Due to the constant SA -LA and MA -LA, the difference between these two values (AV delay correction interval) is a constant as well, which remains unchanged during exercise. Therefore, in selecting the rate responsive AV delay, only hemodynamic and not electrophysiologica] measurements need to be considered. 相似文献
60.
URS NIEDERHÅUSER LUDWIG K. VON SEGESSER THIERRY P. CARREL REAS LASKE ERWIN BAUER MARIETTE SCHÖNBEGK MARKO TURINA 《Pacing and clinical electrophysiology : PACE》1993,16(2):303-308
The long-term results after open intracardiac removal of infected pacing electrodes are presented. Methods: between 1985 and 1990 open intracardiac removal of 19 infected pacing electrodes was performed in seven patients (six male and one femalel, with a mean age of 56 years. The indications were; persisting bacteremia in three; generator pocket infection in four; endocarditis in one; and ventricular tachycardia caused by retracted electrodes in one. All electrodes were fixed in the right heart and extraction by closed methods failed. Percutaneous catheter techniques were not applied in these seven patients. In five patients two ventricular electrodes had to be removed, and in two patients a single one. A total of seven atrial electrodes were removed in six patients (one electrode each in five patients; two electrodes in one patient). All atrial and two ventricular electrodes could be removed through a pursestring suture without use of a pump oxygenator. For the removal of ten ventricular electrodes in six patients (two electrodes each in four patients; 1 electrode each in two patients) a right-sided atriotomy was necessary with cardiopulmonary bypass (CPB). Simultaneously, five new pacing systems were implanted. Results; there were no early or late mortalities. In January 1991, all seven patients are alive and in a mean New York Heart Association Class 1,3 of heart failure after a mean interval of 33 months. In all cases the infection could be controlled with a simultaneous antimicrobial chemotherapy and the postoperative period was free of major complications. Conclusion; open intracardiac removal of retained pacing electrodes with or without use of CPB is a safe procedure without major complications. It is mandatory for all infected pacing electrodes that cannot be extracted by closed methods. 相似文献