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Pig Heart (pig + heart)
Selected AbstractsLack of Effect of Conduction Direction on Action Potential Durations in Anisotropic Ventricular Strips of Pig HeartJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2002GUILLERMO BERTRAN B.Sc. Anisotropy and Repolarization.Introduction: The influence of activation sequence on the rate of rise of the depolarization phase of action potentials in atrial or ventricular muscles has been well established. However, whether myocardial fiber orientation is important in modulating the repolarization process is unclear. Methods and Results: We examined the influence of activation sequence on the repolarization phase of action potentials in epicardial tissues from the right and left ventricles of domestic pigs. Whereas cells from the right ventricle exhibited direction-dependent differences in action potential duration at 30%, 50%, and 90% of full repolarization (190.6 ± 31.1 msec vs 181.8 ± 32.8 msec, 240.3 ± 23.5 msec vs 236.7 ± 25.4 msec, and 291.3 ± 23.7 msec vs 287.4 ± 25.1 msec for longitudinal and transverse propagation, respectively; P < 0.001), a similar duration of repolarization during both directions of propagation was observed in cells from the left ventricle at 50% and 90% of full repolarization (241.4 ± 39.4 msec and 285.5 ± 39.5 msec vs 240.4 ± 38.9 msec and 284.9 ± 39.6 msec for longitudinal and transverse propagation respectively; P = NS). A slight but significant difference was found at 30% of full repolarization in cells from the left ventricle (190.4 ± 39.0 msec vs 187.0 ± 38.0 msec for longitudinal and transverse propagation, respectively; P < 0.05). In the left ventricle, the duration of repolarization did not change as the distance between the recording site and stimulation site increased. Conclusion: The direction of wavefront propagation with respect to fiber orientation may not play an important role in modulating the duration of repolarization in epicardial cells from the left ventricle. [source] Correlation of Biochemical and Hematological Changes with Graft Failure Following Pig Heart and Kidney Transplantation in BaboonsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2003Christoph Knosalla We have explored biochemical and hematologic parameters that might indicate acute humoral xenograft rejection (AHXR) following pig organ transplantation in baboons. Baboons (n = 15) received an immunosuppressive regimen, and underwent a miniature swine or hDAF kidney (Group 1, n = 6) or heart (Group 2, n = 7) transplantation. Control baboons (Group 3, n = 2) received the immunosuppressive regimen without organ transplantation. Blood chemistry and hematologic parameters were measured daily. Baboon and porcine cytomegalovirus were monitored. In Groups 1 and 2, organ grafts survived for up to 29 days. A plasma fibrinogen of <80 mg/dL on 2 consecutive days, and a serum lactate dehydrogenase of >600 U/L and aspartate transaminase of >300 U/L, were associated with the development of AHXR in both heart and kidney grafts. In Group 1, a decrease in platelet count of >150 000/,L within 3 days, or a count of <50 000/,L, were associated with AHXR. In Group 2, a creatine phosphokinase of >500 U/L was associated with graft failure. In Group 3, no abnormalities were observed. The possibility that porcine CMV may play a role in graft injury could not be excluded. Noninvasive parameters were identified that have predictive potential for AHXR. Monitoring of these might enable therapeutic intervention to reverse rejection. [source] Acute cardiovascular effects of tacrolimus in the isolated guinea pig heartJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2005Y. OZKANLAR First page of article [source] Ex vivo hypothermic recirculatory adenoviral gene transfer to the transplanted pig heartTHE JOURNAL OF GENE MEDICINE, Issue 7 2006Keiji Oi Abstract Background To facilitate the application of adenoviral gene therapy in clinical heart transplantation, we developed an ex vivo hypothermic recirculatory adenoviral gene transfer method to the transplanted pig heart. Methods Experimental animals were assigned into three groups; controls, 1 × 108 plaque-forming units (pfu)/ml group and 1 × 109 pfu/ml group. During the 30 min gene transfer perfusion, 200 ml of University of Wisconsin solution containing the adenoviral vector was recirculated through the coronary vessels. The myocardial temperature was maintained below 4 °C and the perfusion pressure was adjusted at 50 mmHg. Results Cardiac myocyte transduction efficiencies in the 1 × 108 pfu/ml group were 0.04% and 0.07%, whereas transduction efficiencies in the 1 × 109 pfu/ml group were widely distributed from 0.45% to 22.62%. The gene transduction efficiency increased with the virus titer. Additionally, no difference in the transduction efficiency was observed between different segments of the left ventricle. The current gene transfer method at 1 × 109 pfu/ml of adenovirus titer enabled homogeneous gene transduction into the transplanted pig heart up to a maximum of 22.62%. Conclusions This model can be applied to a large isolated heart and will greatly facilitate the investigation of gene therapy in large animal models of heart transplantation. Copyright © 2006 John Wiley & Sons, Ltd. [source] The high-resolution structure of pig heart succinyl-CoA:3-oxoacid coenzyme A transferaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2010Shu-Fen Coker The enzyme succinyl-CoA:3-oxoacid coenzyme A transferase (SCOT) participates in the metabolism of ketone bodies in extrahepatic tissues. It catalyses the transfer of coenzyme A (CoA) from succinyl-CoA to acetoacetate with a classical ping-pong mechanism. There is biochemical evidence that the enzyme undergoes conformational changes during the reaction, but no domain movements have been reported in the available crystal structures. Here, a structure of pig heart SCOT refined at 1.5,Å resolution is presented, showing that one of the four enzyme subunits in the crystallographic asymmetric unit has a molecule of glycerol bound in the active site; the glycerol molecule is hydrogen bonded to the conserved catalytic glutamate residue and is likely to occupy the cosubstrate-binding site. The binding of glycerol is associated with a substantial relative movement (a 13° rotation) of two previously undefined domains that close around the substrate-binding site. The binding orientation of one of the cosubstrates, acetoacetate, is suggested based on the glycerol binding and the possibility that this dynamic domain movement is of functional importance is discussed. [source] Crystallization and preliminary X-ray analysis of the full-size cubic core of pig 2-oxoglutarate dehydrogenase complexACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2002Kaoru Suzuki The full-length (untruncated) dihydrolipoamide succinyltransferase from pig heart was crystallized by the hanging-drop vapour-diffusion method. X-ray diffraction patterns indicate that the crystal belongs to space group I432, with unit-cell parameter a = 189.9,Å. The crystal structure has been preliminarily solved at 7,Å resolution by the molecular-replacement method. The unit cell contains two cubic cores, in each of which 24 subunits of E2 are associated according to crystallographic 432 symmetry. At the corners of each cubic core, the catalytic domains of E2s form a trimer through tight interactions around the crystallographic threefold axes. In the electron-density maps, many small broad peaks are observed in regions expected to contain the remaining N-terminal domains (the E1/E3-binding domain and the lipoyl domain), suggesting flexibility of these domains relative to the core. The architecture of the cubic core is similar to that of the other truncated E2s. In the unit cell, however, the core,core contact occurs in a different direction from that found for the truncated proteins. [source] Pacing During Ventricular Fibrillation: Factors Influencing the Ability to CaptureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2001JONATHAN C. NEWTON M.S. Pacing During Ventricular Fibrillation.Introduction: Recent studies showed that pacing atrial and ventricular fibrillation (VF) is possible. The studies presented here determined which parameters influence the efficacy of a pacing train to capture fibrillating ventricular myocardium. Electrode type, current strength, order of pacing trains, polarity, and VF morphology preceding the pacing trains were investigated. Methods and Results: A 504-electrode recording plaque sutured to the right ventricle of pig hearts was used to record the activations of VF and those resulting from the pacing stimulation. Capture of VF by pacing was determined by observing an animated display of the first temporal derivative of the electrograms. A series of electrodes in a line captured the heart more frequently during VF than did a point electrode. Increasing the current strength to 10× diastolic pacing threshold increased the incidence of capture, but increasing this strength further did not. The second or third train of 40 stimuli had greater capture rates than did the first train during the same VF episode. Anodal and cathodal unipolar, and bipolar stimulation were equally efficacious in capturing VF. VF activation during the 1-second interval preceding pacing was more organized for pacing trains that captured than those that did not. The highest incidence of capture, 46% to 61% of pacing trains, occurred with a line of electrodes at 10× diastolic pacing threshold delivered by the second or third train. Conclusion: The probability of a pacing train capturing fibrillating myocardium can be influenced by the pacing protocol parameters. [source] Tissue edema does not change gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced T1 relaxation times of viable myocardium,,JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2005Gang Li MD Abstract Purpose To determine whether tissue edema changes gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced T1 relaxation times of the viable myocardium. Materials and Methods A total of 16 isolated pig hearts were divided into four groups (N = 4/group) and perfused in a Langendorff apparatus. Gd-DTPA was injected into the aortic perfusion line. Tissue edema was then induced by two hours of simultaneous arterial/venous perfusion (SAVP). Myocardial water content and T1 relaxation times were monitored throughout SAVP. The volumes of the extracellular and intracellular compartments were assessed using 31P MRS-detectable markers, phenylphosphonic acid (PPA) and dimethyl methylphosphonate (DMMP). Results Tissue water content in both viable and infarcted myocardium increased significantly during two-hour SAVP. However, Gd-DTPA-enhanced T1 relaxation times of the viable myocardium remained relatively unchanged. Infarcted myocardium, on the other hand, exhibited significant T1 shortening during SAVP. Furthermore, SAVP resulted in significant expansions of both extracellular and intracellular compartments, but the ratio of the volumes of the two compartments remained relatively constant. Conclusion Tissue edema in the viable myocardium does not increase the relative distribution volume of the contrast agent. As a result, edema does not change Gd-DTPA-enhanced T1 relaxation times of the viable myocardium. J. Magn. Reson. Imaging 2005;21:744,751. Published 2005 Wiley-Liss, Inc. [source] Acute effects of escalating doses of amiodarone in isolated guinea pig heartsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2002S. BICER Bicer, S., Patchell, J. S., Hamlin, D. M., Hamlin, R. L. Acute effects of escalating doses of amiodarone in isolated guinea pig hearts. J. vet Pharmacol. Therap.25, 221,226. Cardiac effects of escalating concentrations of amiodarone were determined on isolated perfused guinea pig hearts (Langendorff preparations). Spontaneously beating hearts were instrumented for the measurement of RR, PQ, QRS, QT and QTc durations (from a bipolar electrogram), and dP/dtmax and dP/dtmin from an isovolumetric left ventricular pressure curve. Ten hearts were exposed to escalating concentrations of amiodarone (10,7, 10,6, 10,5 and 10,4 M) in dimethyl sulfoxide (DMSO)/Krebs,Henseleit or to DMSO/Krebs,Henseleit (vehicle). Measurements were collected during the last minute of a 15-min concentration. Means of all parameters were compared by ANOVA with repeated measures design. When compared with vehicle, amiodarone prolonged QT and QTc durations at concentrations >10,6 M. The apparent lengthening of RR, PQ and QRS at concentrations >10,6 M did not achieve statistical significance. Similarly, the apparent decreases in dP/dtmax and dP/dtmin at concentrations >10,6 M did not achieve statistical significance. The putative therapeutic concentration of amiodarone is between 2 and 4 × 10,6 M. In this study, at a concentration of 10,6 M, only RR and dP/dtmin tended to change, but they were not different from vehicle. Thus, amiodarone in this preparation has little potential for cardiac toxicity at therapeutic concentrations. [source] The Three-Dimensional Arrangement of the Myocytes Aggregated Together Within the Mammalian Ventricular MyocardiumTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2009Morten Smerup A 3-D helical arrangement of aggregates of myocytes in a pig's heart revealed by diffusion tensor MRI. See Smerup et al., on page 1, of this issue. [source] | |||||||||||||