[Revitalizing donor livers after cardiovascular arrest with venous oxygen persufflation].

The experimental study investigates the resuscitation of livers procured from non heart beating donors by venous systemic oxygen persufflation in a pig transplantation model. In group 1 livers were harvested from donor animals after 60 min of potassium induced cardiac arrest. Livers were then flushed and preserved in 4 degrees C cold University of Wisconsin solution for 4 hrs.

[Differential effect of preservative solutions (UW vs HTK) on mitochondrial redux status and energy metabolism during liver ischemia with oxygen persufflation].

Venous-systemic oxygen persufflation (VSOP) was performed in rat livers stored at 4 degrees C in either UW or HTK preservation solution. Since tissue anoxia is associated with a transformation of cellular NAD+ to NADH and the latter fluoresces upon UV-epiillumination, homogeneity and intensity of liver oxygenation could be analysed by intravital microscopic detection of NADH fluorescence. VSOP resulted in a significant decrease of the NADH signal, documenting effective tissue oxygenation in both UW and HTK.

[Gaseous oxygen for protection and conditioning of organs during ischemia].

During organ ischemia, oxygen (O2) is the first "substrate", which is depleted. However, during ischemic storage in hypothermia (0-4 degrees C), a sufficient oxygenation is attainable by means of gaseous O2. The results of organ preservation were (mostly) better than those obtained with other methods at the respective times.

No beneficial effects of taurine application on oxygen free radical production after hemorrhagic shock in rats.

Oxygen free radical generation contributes to the reinfusion damage after hemorrhagic shock. Taurine has been proposed to have radical scavenging properties under certain experimental conditions. Therefore the present study was undertaken to investigate if taurine would be able to attenuate adverse effects of shock/resuscitation in male rats (fasted over night).

Successful transplantation of porcine livers after warm ischemic insult in situ and cold preservation including postconditioning with gaseous oxygen.

Background: In order to reduce the shortage of viable donor livers for organ transplantation, a method has been developed that allows even predamaged livers from nonheartbeating donors to be used as transplantable organs.

Methods: Porcine livers were harvested 45 min after cardiac arrest of the nonheparinized donor, preflushed with heparinized saline solution, and subsequently rinsed with University of Wisconsin solution, to which superoxide dismutase was added as an oxygen free radical scavenger. Thereafter, the livers were persufflated with gaseous oxygen via the venous vascular system while immersed in University of Wisconsin solution at 4 degrees C for 4 to 5 hr.

Microscopic analysis of NADH fluorescence during aerobic and anaerobic liver preservation conditions: A noninvasive technique for assessment of hepatic metabolism.

Gaseous insufflation of oxygen via the venous vascular system is thought to be an useful tool for preventing anoxic tissue injury during extended time periods of ischemic preservation and for allowing for an improved recovery of organ function after transplantation. The present study aimed at the application of a noninvasive technique for monitoring effectiveness and homogeneity of gaseous areation by using an epiillumination microscopic technique for assessment of tissue nicotinamide adenine dinucleotide (NADH) fluorescence. Rat livers were flushed with and stored in University of Wisconsin solution at 4 degrees C for 48 h (n = 20).

Cellular signal level of cyclic AMP and functional integrity of the small bowel after ischemic preservation: an experimental pilot study in the rat.

The intestinal mucosa is one the tissues most sensitive to ischemia. Anoxia of the gut is known to result in an early impairment of cellular permeability and transcapillary barrier function upon reperfusion. In vitro, an increased permeability of endothelial cell monolayers could be shown to be related to a decrease in cellular content of cyclic AMP (cAMP).

Cold preservation of the small intestine with the new Celsior-solution. First experimental results.

The aim of the present study was to evaluate the potential of Celsior, a recently developed cardioplegic and heart storage solution, to protect the small bowel during ischemic storage. Small bowel segments were isolated from rats, flushed with either UW or Celsior solution, and cold-stored for 18 h at 4 degrees C in the respective solution. After ischemic storage, some preparations were freeze-clamped for analysis of tissue metabolites while other preparations were tested for structural and functional integrity by isolated perfusion in vitro using a previously validated model.

Effect of glutamine or glucagon-insulin enriched total parenteral nutrition on liver and gut in 70% hepatectomized rats with colon stenosis.

Background: Malnutrition of enterocytes is believed to facilitate the breakdown of the intestinal mucosal barrier, furthering a translocation of enteric bacteria with subsequent severe infection, which has been described after extensive hepatectomy. Glutamine and glucagon insulin are said to attenuate the malnutrition of enterocytes. To determine whether this was true, the effects on the remnant liver and the gut of total parenteral nutrition supplemented by admixtures of glutamine and/or glucagon insulin were investigated in rats subjected to massive hepatectomy and transient intestinal stasis.

Biophysical aspects of liver aeration by vascular persufflation with gaseous oxygen.

Background: Venous systemic oxygen persufflation of the liver (i.e., gaseous insufflation of oxygen via the venous vascular system) has proven to be an effective tool for preventing anoxic tissue injury during extended time periods of ischemic preservation.

Hypothermic storage alone in lung preservation for transplantation: a metabolic, light microscopic, and functional analysis after 18 hours of preservation.

Background: Current lung preservation consists of flushing of the donor organs, with successive hypothermic storage in an inflated state. Recently, hypothermic storage alone was reported to be superior in terms of functional recovery. This study was designed to investigate the metabolic, morphologic, and functional consequences of hypothermic storage alone, in experimental lung preservation.

Reduction of proteolysis by venous-systemic oxygen persufflation during rat liver preservation and improved functional outcome after transplantation.

An increase of cytosolic proteolytic activity during ischemic preservation and consecutive tissue degradation have recently been recognized as a major pathogenetic factor for liver injury during ischemia/reperfusion. In the present study, we propose a method for preventing proteolytic tissue disintegration, which results in improved recovery of the liver after transplantation. Livers were harvested from rats and stored for 24 hr at 4 degrees C in University of Wisconsin solution (group A).

Assessment of intestinal integrity after ischemic preservation by luminal and vascular perfusion in vitro.

Background: In the present study a technique for isolated perfusion of rat intestines in vitro should be tested as an evaluative tool in the assessment of intestinal alterations related to ischemia and reoxygenation.

Methods: Segments of upper jejunum (15 cm) were isolated from Wistar rats with vascular pedicle (superior mesenteric artery, SMA and portal vein). The SMA was cannulated with polyethylene tubing and flushed with 10 ml of University of Wisconsin (UW) preservation solution.

Resuscitation of cadaveric livers from non-heart-beating donors after warm ischemic insult: a novel technique tested in the rat.

Clinical liver transplantation has become the therapy of choice in end-stage liver disease, but the limited availability of suitable donor organs still impedes its widespread application. In order to increase the availability of donor organs for liver transplantation, it would be advantageous if ischemically damaged livers could be resuscitated from cadavers in which the heart has stopped beating. A method for doing this has been developed in a rat model.

No evidence for a protective effect of ascorbic acid on free radical generation and liver injury after hemorrhagic shock in rats.

Oxygen free radicals have been shown to be implicated in ischemic tissue injury, and free radical-induced reactions may also play an important role in the pathophysiology of circulatory shock. The present study was designed to investigate the potential use of ascorbic acid as an exogenous antioxidant on the liver's recovery from hemorrhagic shock in situ. Rats (fasted overnight) were subjected to 60 min of hemorrhagic shock (HS) (mean arterial pressure = 40 mmHg) under pentobarbital anesthesia, followed by retransfusion of the shed blood.

Synthesis of high energy phosphates during cold ischemic rat liver preservation with gaseous oxygen insufflation.

The depletion of biochemical energy stores during anoxic ischemic preservation is a major problem affecting the viability of the graft in transplantation medicine. After cessation of blood flow and, thus, lack of metabolic substrates and oxygen supply, a swift decrease of energy-rich phosphates can be observed in the tissue, since endergonic metabolic processes continue, but no further oxidative regeneration of biochemical energy stores will take place. We investigated the effect of a continuous gaseous oxygen supply via the venous vessels during extended ischemic preservation of rat livers in University of Wisconsin preservation solution for 48 hr.

Assessment of oxygen radicals during kidney transplantation--effect of radical scavenger.

In the present study, levels of free oxygen radicals, generated in the very early period of reperfusion during human kidney transplantation, were assessed by determination of malondialdehyde (MDA) levels using a high-pressure liquid chromatography (HPLC) method. Renal blood samples were obtained during reperfusion by intraoperative cannulation of the renal vein. Simultaneously, systemic MDA levels were determined.

Reduction in nonparenchymal cell injury and vascular endothelial dysfunction after cold preservation of the liver by gaseous oxygen.

Reintroduction of oxygen to previously anoxic tissue may result in severe cell injury (oxygen paradox) and contribute to the so-called reperfusion damage of ischemic organs. Our study investigated the influence of simple gaseous oxygen supply during ischemia on nonparenchymal cell alterations upon reperfusion of the liver. Livers from male Wistar rats were isolated, rinsed blood-free and stored for 48 h at 4 degrees C in UW-preservation solution (group 1; n = 6).

Protective effect of taurine on hypoxia and reoxygenation-induced damage of human colon cells (HT 29).

In this experimental model, taurine administered during hypoxia markedly reduced the cell damage due to O2 deficiency, and the beneficial effect outlasted the period of reoxygenation. The mechanisms for the improved survival rates are postulated to be a reduced osmoregulatory disturbance of cellular integrity, improved Ca2+ homeostasis and induction of accelerated cellular growth processes. In our simplified cell culture model the UW solution seems to be the most appropriate solution for the cold (hypoxic) preservation of human colon cells.