Double patch closure of ventricular septal defect with increased pulmonary vascular resistance

BACKGROUND: Closure of a large ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance is associated with significant morbidity and mortality. Pulmonary hypertensive episodes continue to be a major cause of postoperative morbidity and mortality. We designed a fenestrated flap valve double VSD patch in an effort to decrease the morbidity and mortality associated with the closure of a large VSD with elevated pulmonary vascular resistance. METHODS: Eighteen children (mean age, 5.7 years) with a large VSD and elevated pulmonary vascular resistance (mean, 11.4 Wood units) underwent double patch VSD closure using moderately hypothermic cardiopulmonary bypass and cardioplegic arrest. The routine VSD patch was fenestrated (4 to 6 mm) and on the left ventricular side of the patch, a second, smaller patch was attached to the fenestration along its superior margin before closure of the VSD. RESULTS: All children survived operation and were weaned from inotropic and ventilator support within 48 hours postoperatively. Postoperative pulmonary artery pressures were significantly lower than preoperative values. One child died 9 months postoperatively. CONCLUSIONS: Closure of a large VSD in children with elevated pulmonary vascular resistance can be performed with low morbidity and mortality when a flap valve double VSD patch is used.     

Effects of granisetron with doxorubicin or epirubicin on ECG intervals

Commercially available serotonin-type 3 (5-HT3) receptor antagonists (ondansetron, granisetron, and tropisetron) have shown no clinically significant adverse effects on the cardiovascular system. In the dose-ranging evaluation of dolasetron, computer-generated ECGs revealed clinically asymptomatic prolongations of ECG intervals. We performed a clinical trial in which the possible changes in ECG intervals following a single 3-mg i.v. injection of granisetron and an injection of either doxorubicin or epirubicin were registered using computerized ECG analysis in cancer patients. A total of 30 patients who were designated to receive 3 mg granisetron i.v. for the prophylaxis of emesis induced by doxorubicin or epirubicin were entered into the study. Computer-generated ECG tracings were obtained before treatment, following the injection of 3mg granisetron, and immediately after doxorubicin or epirubicin injection. The mean PR interval duration increased from 160 to 166 ms after granisetron infusion (P=0.02). Doxorubicin and epirubicin did not potentiate this change. There was no statistically significant change in cardiac rhythm, QRS duration, or QTc intervals. The observed minor changes in the PR time following i.v. injection of granisetron do not seem to be of clinical relevance.     

Clinical, neurophysiological and hemodynamic effects of a new nondepolarizing myorelaxant mivacurium in heart surgery patients]

Thirty patients aged 23 to 65 years with ASA class III operated on the heart under total intravenous anesthesia were examined after the Good Clinical Practice protocol. Mivacurium in bolus dose of 0.2 mg/kg was injected for intubation of the trachea; neuromuscular blocking (NMB) was maintained by a repeated injection of the drug in a dose of 0.15 mg/kg, after which it was infused at a rate of 1 to 10 micrograms/kg/min. Accelerometric control of neuromuscular conduction was carried out by the Organon (Belgium) TOF-Guard device. Central and peripheral hemodynamics was monitored. Side effects of the drug were recorded. Bolus injection of mivacurium in a dose of 0.2 mg/kg caused T1 suppression (90%) after 2.6 +/- 0.7 min. Maximal (97.7 +/- 4.5%) suppression was observed after 4.17 +/- 2.5 min. The conditions of intubation of the trachea after 3.9 +/- 1.8 min in the presence of 78 to 100% T1 suppression (97.7 +/- 4.5%) were considered excellent or good in 96.6% of cases. Clinically and neurophysiologically sufficient muscle relaxation after the first injection of the drug persisted for 27.7 +/- 7.3 min. Minimal rate of infusion for maintaining the NMB at 95 +/- 4% level of T1 suppression was 6.3 +/- 1.7 micrograms/kg/min. Bolus injection of mivacurium in a dose of 0.2 mg/kg for 60 sec involved a 1-3-min drop of the mean arterial pressure by 10.5% and a 10.3% decrease of heart rate. Repeated bolus injection of the drug in a dose of 0.15 mg/kg and its infusion did not change the peripheral and central hemodynamics. The most typical side effect of the drug in a dose of 0.2 mg/kg is short-term reversible reddening of the skin of the face and neck, observed in 20% of patients. The results permit us to consider mivacurium as an effective, safe, and controllable agent, which can be used in cardiosurgical patients.     

Application of free-flow electrophoresis for isolation and purification of proteins and peptides

Free-flow electrophoresis (FFE) has been applied to the separation and purification of a variety of proteins and polypeptides: bee venom, tumor necrosis factor, interleukin-1beta, interferon-gamma and superoxide dismutase. FFE at constant pH and conductivity of the carrying buffer is shown to be efficient at various separation schemes. In some cases, the method allows us to obtain proteins with a purity of more than 90% at a productivity of 20-30 mg/h. An electrophoretic apparatus with a new, multi-sectional construction of the electrophoretic chamber and a system for cross-displacement of carrying buffer in the chamber is described.     

Mechanical stimulation initiates intercellular Ca2+ signaling in intact tracheal epithelium maintained under normal gravity and simulated microgravity

We investigated mechanically induced cell-to-cell Ca2+ signaling in a preparation of rabbit tracheal epithelium close to its in vivo condition. We used confocal microscopy to analyze changes in intracellular free calcium concentration ([Ca2+]i) in intact ciliated tracheal mucosal explants loaded with the Ca2+-indicator dye, fluo-3. When a single cell in the epithelium was transiently stimulated with a microprobe, [Ca2+]i increased in the stimulated cell and then increased in surrounding cells. In the absence of extracellular Ca2+, the [Ca2+]i increases had a smaller amplitude and spread to fewer cells. Treatment of the cells with thapsigargin, in the presence of extracellular Ca2+, more markedly reduced the spread of elevated [Ca2+]i. These results suggest that the propagated [Ca2+]i increases are due to mobilization of Ca2+ from intracellular stores and, possibly, the influx of extracellular Ca2+. The mechanically stimulated [Ca2+]i increases were accompanied by propagated increases in ciliary beat frequency. Since microgravity has been shown to alter signal transduction, we investigated whether simulated microgravity affects the mechanically stimulated cell-to-cell Ca2+ signaling observed in tracheal epithelium. Tissues were maintained for 3-8 d in a rotating wall vessel which simulates microgravity conditions. Cells maintained in simulated microgravity exhibited mechanically induced [Ca2+]i increases not significantly different in magnitude, in speed of propagation, or in the number of cells involved, from tissue maintained at unit gravity. Our results suggest that intercellular Ca2+ signaling coordinates cellular activity, including ciliary beating, within the tracheal epithelium in vivo and that this function is not compromised in microgravity.