Membrane specific carbonic anhydrase (CAIV) expression in human tissues.

Membrane-bound carbonic anhydrase IV (CAIV) expression has been evaluated in a range of fetal and adult human tissues and in cell culture. All tissues tested showed expression of CAIV, assessed by Western blotting, with a single immunodetected band at 55 kDa. The levels varied in fetal lung and liver during development and in various zones of the fetal brain. CAIV was clearly expressed in lung, pancreatic tumour and skin cell cultures.

Donor heart preservation with a novel hyperpolarizing solution: superior protection compared with University of Wisconsin solution.

OBJECTIVES: A donor heart preservation solution was designed to use hyperpolarized arrest with the adenosine triphosphate-sensitive potassium-channel opener pinacidil. This solution contained concentrations of potassium, sodium, calcium, magnesium, lactobionate, and the buffer histidine specifically chosen to minimize intracellular calcium accumulation associated with prolonged ischemia. METHODS: Twenty-four rabbit hearts were randomly assigned to receive 1 of 3 preservation solutions in a crystalloid-perfused Langendorff model: (1) prototype solution containing a 0.5 mmol/L concentration of pinacidil, (2) prototype solution without pinacidil as control, and (3) University of Wisconsin solution. Thirty minutes of initial perfusion preceded baseline data acquisition. Data comprised left ventricle pressure-volume curves generated by inflating an intraventricular latex balloon. After cardioplegic administration, hearts underwent 4 hours of hypothermic storage, followed by 60 minutes of reperfusion and postischemic data acquisition. RESULTS: Postischemic developed pressure was better preserved by pinacidil solution (92.4% +/- 4.5%) than by the control (74.9% +/- 3.4%, P =.01) and University of Wisconsin solutions (66.7% +/- 5.1%, P =.001). Diastolic negative dP/dT was better preserved by pinacidil solution (104.4% +/- 10.2%) than by the control (80.2% +/- 4.2%, P =.034) and University of Wisconsin solutions (71.7% +/- 7.0%, P =.015). Diastolic compliance, expressed as baseline/postischemic diastolic slope ratios, was more poorly preserved by University of Wisconsin solution (0.67 +/- 0.07) than by the pinacidil (0.88 +/- 0.05, P =.041) and control solutions (0.87 +/- 0.05, P =.021). Postischemic coronary flow was higher in hearts exposed to pinacidil solution (77.8% +/- 3.0%) than in those exposed to the control (66.8% +/- 2.4%) and University of Wisconsin solutions (70.9% +/- 4.0%, P =.07). CONCLUSIONS: The superiority of the pinacidil solution in this experiment demonstrated that hyperpolarized arrest with potassium-channel openers improves donor heart preservation when administered in a novel histidine-buffered lactobionate-enriched vehicle.

Modifications in surgical implantation of the Penn State electric total artificial heart.

BACKGROUND: Two modifications of the surgical implantation protocol for the Penn State Total Artificial Heart (ETAH) were evaluated: Phrenic nerve ischemia was prevented by minimizing dissection and traction; and hemostasis was augmented and ETAH cuff anastomoses reinforced by using fibrin glue. METHODS: Thirteen Holstein calves underwent orthotopic surgical implantation of the Penn State ETAH between February 1998 and August 2000. Mean hemodynamic and laboratory chemistry variables from the first postoperative week were compared between calves receiving the original (n = 7) and modified (n = 6) protocol. RESULTS: Calves assigned to the modified protocol displayed an improvement in the Po2/FiO2 ratio compared to original (419.4 +/- 17.5 vs 336.3 +/- 35.4, respectively; p = 0.05). All additional parameters were equivalent between groups. The percent survival of animals receiving the modified protocol at 2, 4, and 12 weeks was higher than that of animals that underwent the original protocol. Original-protocol calf deaths consisting of hemothorax (n = 3), and respiratory failure (n = 1) were prevented in the modified protocol. CONCLUSIONS: Our results suggest that manipulations in surgical protocol may promote increased survival in calves implanted with the Penn State ETAH.