Epithelial sodium channels regulate cystic fibrosis transmembrane conductance regulator chloride channels in Xenopus oocytes.

The cystic fibrosis transmembrane conductance regulator (CFTR), in addition to its well defined Cl(-) channel properties, regulates other ion channels. CFTR inhibits epithelial Na(+) channel (ENaC) currents in many epithelial and nonepithelial cells. Because modulation of net NaCl reabsorption has important implications in extracellular fluid volume homeostasis and airway fluid volume and composition, we investigated whether this regulation was reciprocal by examining whether ENaC regulates CFTR. Co-expression of human (h) CFTR and mouse (m) alphabetagammaENaC in Xenopus oocytes resulted in a significant, 3.7-fold increase in whole-cell hCFTR Cl(-) conductance compared with oocytes expressing hCFTR alone. The forskolin/3-isobutyl-1-methylxanthine-stimulated whole-cell conductance in hCFTR-mENaC co-injected oocytes was amiloride-insensitive, indicating an inhibition of mENaC following hCFTR activation, and it was blocked by DPC (diphenylamine-2-carboxylic acid) and was DIDS (4, 4'-diisothiocyanatostilbene-2,2'-disulfonic acid)-insensitive. Enhanced hCFTR Cl(-) conductance was also observed when either the alpha- or beta-subunit of mENaC was co-expressed with hCFTR, but this was not seen when CFTR was co-expressed with the gamma-subunit of mENaC. Single Cl(-) channel analyses showed that both CFTR Cl(-) channel open probability and the number of CFTR Cl(-) channels detected per patch increased when hCFTR was co-expressed with alphabetagammamENaC. We conclude that in addition to acting as a regulator of ENaC, CFTR activity is regulated by ENaC.

Ultra-fast track hospital discharge using conventional cardiac surgical techniques.

BACKGROUND: Recent introduction of minimally invasive adult cardiac surgical techniques has emphasized the advantage of early hospital discharge. However, we chose an alternative approach to determine the safety, efficacy, and feasibility of ultra-fast track protocols while retaining both standard surgical exposure (median sternotomy) and conventional cardiac surgical techniques (hypothermia, cardiopulmonary bypass with cardiac arrest, and optimal myocardial protection). METHODS: From September 1995 to January 1998, a total of 258 consecutive patients underwent cardiac procedures by a single surgeon. Acceleration of clinical pathways was used to initiate earlier discharges. Stringent postdischarge follow-up was implemented. Prospectively entered data were then analyzed retrospectively. RESULTS: A variety of isolated as well as combined coronary and valve procedures were performed. Of the 258 patients operated on during this entire study period, a total of 144 patients (56%) were discharged within postoperative days 1 to 4 (ultra-fast track discharge). Over the past 12 months, this incidence increased to 70% (76 of 108 patients). Approximately 50% of these patients were operated on urgently or emergently. To date, there have been no deaths in this ultra-fast track group. There were eight brief readmissions, of which one was for rewiring of a noninfected sternal dehiscence, and the remaining were for cardiac diagnostic studies or a noncardiac problem altogether. CONCLUSIONS: Conventional cardiac operation can allow ultrafast hospital discharges while retaining the advantage of time-tested techniques and providing wider application without requiring new or additional training or equipment.

Intestinal tamponade: cardiac compression by intestinal contents.

Intrapericardial herniations represent a rare complication of abdominal or chest trauma. We describe clinical tamponade that developed in an elderly patient after manual reduction of an umbilical hernia. Echocardiography disclosed loops of bowel within the pericardium confirming the clinical diagnosis and leading to successful surgical repair.

Digital computer analysis of M-scan echocardiograms.

In the past few years, echocardiography has emerged as a useful noninvasive clinical tool in cardiac diagnosis. Conventional methods for analyzing echocardiographic data involve time consuming and tedious manual techniques for measuring various distances and computing cardiac parameters of interest. This paper describes a useful method for automating the analysis of M scan echocardiograms both for routine clinical work as well as for special research oriented ultrasonic cardiac studies. Using a GRAF/PEN digitizer interfaced to a PDP-11 minicomputer system, relevant points of the ventricular and mitral valve interfaces, R-R intervals, and time and distance calibration points are entered from hard copies of M scan echocardiograms. The computer then determines all the parameters of interest such as left ventricular (LV) diameters, LV volumes, LV mass, ejection fraction, stroke volume, cardiac output, septal and posterior wall dynamics, as well as such mitral valve (MV) parameters as opening/closing velocities, excursions, and areas subtended by both MV leaflets. The data and results are stored on disc or tape and a report of the results is immediately available from a printer for incorporation into the patient's record file.