Phosphorylation of extrajunctional Cx43 in ischemic-preconditioned rat hearts.

Ischemic preconditioning (IP) has been found to intensify ischemia-induced spreading of connexin 43 (Cx43) into the extrajunctional plasma membrane of the rat heart. Since ischemia is known to induce connexin dephosphorylation and plasmalemmal permeabilization, we considered whether IP might delay dephosphorylation of also extrajunctional connexin and thus impede myocyte permeabilization. Regional myocardial ischemia of both 15 and 45 min duration with and without IP, respectively, was induced in anesthetized rats.

Gene expression of the Na-Ca2+ exchanger, SERCA2a and calsequestrin after myocardial ischemia in the neonatal rabbit heart.

Background: Neonatal hearts are less susceptible to developing myocardial dysfunction after hypoxia and/or ischemia than adult hearts. Differences in intracellular calcium homeostasis may be responsible for reduced calcium overload of the immature myocardium leading to the observed protection against ischemia.

Objective: To assess differences in baseline and post-ischemic gene expression of calcium handling proteins after ischemia in neonatal and adult rabbit hearts.

Redistribution of connexin43 in regional acute ischemic myocardium: influence of ischemic preconditioning.

Connexins are known to play an essential role in the ischemic preconditioning (IP) of the heart; their functional role in this process, however, has not been clearly defined. For this reason, anesthetized rats were subjected to regional myocardial ischemia, with or without IP or reperfusion. In frozen sections of hearts, fluorescence immunohistochemical staining for connexin43 (Cx43) was performed.

Effect of lower body negative pressure and gravity on regional lung ventilation determined by EIT.

The aim of our study was to check the effect of varying blood volume in the chest and gravity on the distribution of ventilation and aeration in the lungs. The change in intrathoracic blood volume was elicited by application of lower body negative pressure (LBNP) of -50 cmH2O. The variation of gravity in terms of hypogravity (approximately 0g) and hypergravity (approximately 2g) was induced by changes in vertical acceleration achieved during parabolic flights.

Distribution of ventilation in young and elderly adults determined by electrical impedance tomography.

To determine the effect of age and posture on regional lung ventilation, eight young (26 +/- 1 years, mean +/- S.D.) and eight old (73 +/- 5 years) healthy men were studied by electrical impedance tomography in four body positions (sitting, supine, right and left lateral).

Efficacy of postoperative rewarming after cardiac surgery.

Objective: To compare the efficacy of forced-air warmers and radiant heaters on rewarming after cardiac surgery in a prospective randomized study.

Methods: Fifty male patients who had undergone coronary artery bypass graft surgery were studied. The control group (Gr.

Na(+)-channel modulation, a new principle of inotropic intervention: effects on hemodynamic and myocardial energetics in the immature rabbit heart.

Na+-channel modulators exert their positive inotropic action without affecting the adenylate-cyclase pathway by an increase in the open probability of the sarcolemmal Na+ channels. Although inotropic effects in neonatal hearts are less pronounced compared with adult hearts, the Na+-channel modulator BDF 9148 increases contractility and relaxation velocity in immature myocardium. Effects on hemodynamics and myocardial energetics are not known.

Acoustic phenomena and valve dysfunction in cardiac prostheses: data acquisition and collection via the Internet.

Background And Aim Of The Study: The study aim was to investigate whether: (i) by detection of changing acoustic sound phenomena, minimal changes in prosthetic valve function may be detected earlier than with echocardiography, invasive diagnosis or clinically; (ii) patients can record and pass on signals with a high level of reproducibility from any location via the Internet; and (iii) clinical data evaluation permits conclusions to be drawn on changes in the functional state of a prosthetic replacement valve.

Methods: Simulation studies were carried out using a mock circulation device. Aortic valve replacement (AVR) using extracorporeal circulation was performed in pigs, valve function was artificially disturbed, and valve sounds were recorded.

Extent of damage in ischemic, nonreperfused, and reperfused myocardium of anesthetized rats.

To investigate the localization of the earliest damage in ischemic and ischemic-reperfused myocardium, anesthetized rats were subjected to coronary occlusion for 15, 30, 45, or 90 min. One-half of the animals in each group had no reperfusion, whereas the other half was reperfused for 14 min. With the use of histological methods, preferentially in the periphery of the area at risk, localized zones were detected that lacked the hypoxia-specific increase in NADH fluorescence.

Distribution of lung ventilation in spontaneously breathing neonates lying in different body positions.

Objective: The aim of our study was to determine the effect of the irregular spontaneous breathing pattern and posture on the spatial distribution of ventilation in neonates free from respiratory disease by the non-invasive imaging method of electrical impedance tomography (EIT). Scanning of spontaneously breathing neonates is the prerequisite for later routine application of EIT in babies with lung pathology undergoing ventilator therapy.

Design: Prospective study.

Contribution of myoglobin-induced increases in vascular resistance to shock decompensation in experimental Crush-syndrome in anesthetized rats.

Myoglobin is known to become nephrotoxic when released in greater amounts from skeletal muscle into the general circulation during shock. The present study deals with the question as to whether a myoglobin-induced increase in vascular tone additionally contributes to the detrimental role of this protein in hypovolemic shock. Anesthetized rats were subjected to 250 mg kg x h(-1) myoglobin infused i.

Regional lung perfusion as determined by electrical impedance tomography in comparison with electron beam CT imaging.

The aim of the experiments was to check the feasibility of pulmonary perfusion imaging by functional electrical impedance tomography (EIT) and to compare the EIT findings with electron beam computed tomography (EBCT) scans. In three pigs, a Swan-Ganz catheter was positioned in a pulmonary artery branch and hypertonic saline solution or a radiographic contrast agent were administered as boli through the distal or proximal openings of the catheter. During the administration through the proximal opening, the balloon at the tip of the catheter was either deflated or inflated.

Detection of local lung air content by electrical impedance tomography compared with electron beam CT.

The aim of the study was to validate the ability of electrical impedance tomography (EIT) to detect local changes in air content, resulting from modified ventilator settings, by comparing EIT findings with electron beam computed tomography (EBCT) scans obtained under identical steady-state conditions. The experiments were carried out on six anesthetized supine pigs ventilated with five tidal volumes (VT) at three positive end-expiratory pressure (PEEP) levels. The lung air content changes were determined both by EIT (Goe-MF1 system) and EBCT (Imatron C-150XP scanner) in six regions of interest, located in the ventral, middle, and dorsal areas of each lung, with respect to the reference air content at the lowest VT and PEEP, as a change in either local electrical impedance or lung tissue density.

Effects of different inotropic interventions on myocardial function in the developing rabbit heart.

The development of the mammalian heart is characterized by substantial changes in myocardial performance. We studied the ontogeny of myocardial function with and without various inotropic interventions in the developing isolated, antegrade-perfused rabbit heart (2d, 8d, 14d, 28d, n = 96). Myocardial function was related to the protein expression of the sarcolemmal Na(+)-Ca2+ exchanger and to the sarcoplasmic Ca(2+)-ATPase.