A rapid and efficient method for the extraction and identification of menaquinones from Actinomycetes in wet biomass.

BACKGROUND: Menaquinones are constituents of prokaryote cell membranes where they play important functions during electron transport. Menaquinone profiles are strongly recommended for species classification when proposing a new Actinomycetes taxon. Presently, the most widely used methods to determine menaquinones are based on freeze-dried cells. Taxonomic research in our lab has revealed that menaquinone concentrations are low for some species of the genus Microbacterium, leading to difficulties in identifying menaquinones. RESULTS: Menaquinones extracted using the novel lysozyme-chloroform-methanol (LCM) method were comparable in quality to those obtained using the Collins method, the most widely used method. All tested strains extracted via the LCM method showed higher concentrations of menaquinones than those extracted via the Collins method. For some Microbacterium strains, the LCM method exhibited higher sensitivity than the Collins method, and more trace menaquinones were detected with the LCM method than the Collins method. In addition, LCM method is faster than the Collins method because it uses wet cells. CONCLUSION: The LCM method is a simple, rapid and efficient technique for the extraction and identification of menaquinones from Actinomycetes.

Hypertonic saccharide solution delays pyroptosis in murine macrophages regardless of the membrane binding of gasdermin D N-terminal.

Pyroptosis is a type of programmed lytic cell death that could be activated by either the canonical or noncanonical inflammasome pathway. In this study, we aimed to examine the effect of hypertonic solution on noncanonical pyroptosis in macrophage. We found that although hypertonic solution had a general inhibitory effect on noncanonical pyroptosis, the underlying mechanism varied by the solute causing hypertonicity. Specifically, hypertonic NaCl or KCl solution inhibited the cleavage of gasdermin D, the pore-forming protein in pyroptosis, whereas hypertonic saccharide solution did not affect the cleavage or membrane binding of gasdermin D. In this case, nevertheless, pyroptosis was still inhibited as evidenced by the preserved mitochondria activity and cell membrane permeability.

Hypertonic Mannitol for the Prevention of Intradialytic Hypotension: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: Intradialytic hypotension (IDH) is a common complication at the initiation of hemodialysis (HD) therapy, is associated with greater mortality, and may be related to relatively rapid shifts in plasma osmolality. This study sought to evaluate the effect of an intervention to minimize intradialytic changes in plasma osmolality on the occurrence of IDH. STUDY DESIGN: Double-blind, single-center, randomized, controlled trial. SETTING & PARTICIPANTS: Individuals requiring initiation of HD for acute or chronic kidney disease. INTERVENTION: Mannitol, 0.25g/kg/h, versus a similar volume of 0.9% saline solution during the first 3 HD sessions. OUTCOMES: The primary end point was average decline in systolic blood pressure (SBP). The secondary end point was the proportion of total sessions complicated by IDH (defined as a decrease ≥ 20mm Hg from the pre-HD SBP). Exploratory end points included biomarkers of cardiac and kidney injury. RESULTS: 52 patients were randomly assigned and contributed to 156 study visits. There were no significant differences in average SBP decline between the mannitol and placebo groups (15±11 vs 19±16mm Hg; P = 0.3). The proportion of total sessions complicated by IDH was lower in the mannitol group compared to placebo (25% vs 43%), with a nominally lower risk for developing an episode of IDH (OR, 0.38; 95% CI, 0.14-1.00), though this finding was of borderline statistical significance (P = 0.05). There were no consistent differences in cardiac and kidney injury biomarker levels between treatment groups. LIMITATIONS: Modest sample size and number of events. CONCLUSIONS: In this pilot randomized controlled trial studying patients requiring initiation of HD, we found no difference in absolute SBP decline between those who received mannitol and those who received saline solution. However, there were fewer overall IDH events and a nominally lower risk for dialysis sessions being complicated by IDH in the mannitol group. A larger multicenter randomized controlled trial is warranted. FUNDING: Government funding to an author (Dr Mc Causland is supported by National Institute of Diabetes and Digestive and Kidney Diseases grant K23DK102511). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01520207.

Low osmolality and shear stress during liposuction impair cell viability in autologous fat grafting.

BACKGROUND: Liposuction and subsequent autologous fat grafting have become essential techniques for fat augmentation in plastic surgery. However, standard harvesting techniques that ensure the survival of adipocytes and stromal vascular fraction (SVF) cells and thus preserve the transplanted fat volume are lacking. In particular, the effect of different parameters of the tumescent solution has not been studied in this context. We hypothesized that the osmolality of the tumescent solution could have a significant effect on the survival of adipocytes and SVF cells. METHODS: We developed two distinct in vitro models based on freshly harvested excision fat from patients undergoing surgical treatment. First, we investigated the effect of osmolality by incubating excision fat in different tumescent solutions and analyzed the total cell survival and the differentiation potential of SVF cells. Vital whole-mount staining, isolation yield of SVF cells, clonogenicity, and osteogenic and adipogenic differentiation capacities were analyzed. Second, we addressed the additional effect of mechanical stress by simulating a liposuction on pieces of excision fat after incubation with the tumescent solutions. RESULTS: Osmolality of the tumescent solution by itself did not have a significant effect on adipocyte and SVF viability or SVF differentiation. However, when osmolality was combined with liposuction, a significant trend toward lower viability and more lipid droplets with lower osmolality was observed. Especially, SVF viability was significantly lower after liposuction with a hypotonic (150 mOsm/kg) solution. CONCLUSION: This study demonstrates the considerable effect of osmolality during liposuction and may lead to the development of "cell-protective" tumescent solutions.

Optimizing Irreversible Electroporation Ablation with a Bipolar Electrode.

PURPOSE: To optimize single-insertion bipolar irreversible electroporation (IRE) by characterizing effects of electric parameters and controlling tissue electric properties in a porcine model. MATERIALS AND METHODS: Single-insertion electrode bipolar IRE was performed in 28 in vivo pig livers (78 ablations). First, effects of voltage (2,700-3,000 V), number of pulses, repeated cycles (1-6 cycles), and pulse width (70-100 µs) were studied. Next, electric conductivity was altered by instillation of hypertonic and hypotonic fluids. Finally, effects of thermal stabilization were assessed using internal electrode cooling. Treatment effect was evaluated 2-3 hours after IRE. Dimensions were compared and subjected to statistical analysis. RESULTS: Delivering 3,000 V at 70 µs for a single 90-pulse cycle yielded 3.8 cm ± 0.4 × 2.0 cm ± 0.3 of ablation. Applying 6 cycles of energy increased ablation to 4.5 cm ± 0.4 × 2.6 cm ± 0.3 (P < .001). Further increasing pulse lengths to 100 µs (6 cycles) increased ablation to 5.0 cm ± 0.4 × 2.9 cm ± 0.3 (P < .001) but resulted in electric spikes and system crashes in 40%-50% of cases. Increasing tissue electric conductivity via hypertonic solution instillation in surrounding tissues increased frequency of generator crashes, whereas continuous instillation of distilled water eliminated this arcing phenomenon but reduced ablation to 2.3 cm ± 0.1. Controlled instillation of distilled water when electric arcing was suspected from audible popping produced ablations of 5.3 cm ± 0.6 × 3.1 cm ±0.3 without crashes. Finally, 3.1 cm ± 0.1 short-axis ablation was achieved without system crashes with internal electrode perfusion at 37°C versus 2.3 cm ± 0.1 with 4°C-10°C perfusion (P < .001). CONCLUSIONS: Bipolar IRE ablation zones can be increased with repetitive high voltage and greater pulse widths accompanied by either judicious instillation of hypotonic fluids or internal electrode perfusion to minimize unwanted electric arcing.

Protective effects of hydrogen-rich saline against N-methyl-N-nitrosourea-induced photoreceptor degeneration.

The N-methyl-N-nitrosourea (MNU)-treated rat is typically used as an animal model of chemically-induced retinitis pigmentosa (RP). Reactive oxygen species (ROS) have been recognized as the crucial contributor to the retinal photoreceptor apoptosis seen in MNU-treated rats. In the present study, we explored the therapeutic effects of hydrogen-rich saline (HRS), a selective ROS scavenger, on MNU-induced photoreceptor degeneration. Intraperitoneal (IP) administration of HRS ameliorated MNU-induced photoreceptor degeneration in terms of morphology and function: Sharply decreased thickness of the retinal outer nuclear layer (ONL) and flattened photopic and scotopic electroretinogram (ERG) waveforms, typically seen in response to MNU treatment, were substantially rescued in rats cotreated with MNU and HRS (MNU + HRS). Moreover, the terminal deoxyuridine triphosphate nick-end labeling (TUNEL) assay revealed a smaller number of apoptotic photoreceptors in the MNU + HRS group compared that in the MNU group. Compared to MNU-treated rats, retinal malondialdehyde (MDA) content in MNU + HRS rats significantly decreased while superoxide dismutase (SOD) activity significantly increased. Morphological and multi-electrode array (MEA) analyses revealed more efficient preservation of the architecture and field potential waveforms in particularly the peripheral regions of the retinas within the MNU + HRS group, compared to that in the MNU group. However, this enhanced protection of structure and function in the peripheral retina is unlikely the result of site-dependent variation in the efficacy of HRS; rather, it is most likely due to reduced susceptibility of peripheral photoreceptors to MNU-induced degeneration. Inner retinal neuron function in the MNU + HRS rats was better preserved, with fewer apoptotic photoreceptors in the ONL. Collectively, these results support the rationale for future clinical evaluation of HRS as a therapeutic agent for human RP.

Meta-analysis of high- versus low-chloride content in perioperative and critical care fluid resuscitation.

BACKGROUND: The objective of this systematic review and meta-analysis was to assess the relationship between the chloride content of intravenous resuscitation fluids and patient outcomes in the perioperative or intensive care setting. METHODS: Systematic searches were performed of PubMed/MEDLINE, Embase and Cochrane Library (CENTRAL) databases in accordance with PRISMA guidelines. Randomized clinical trials, controlled clinical trials and observational studies were included if they compared outcomes in acutely ill or surgical patients receiving either high-chloride (ion concentration greater than 111 mmol/l up to and including 154 mmol/l) or lower-chloride (concentration 111 mmol/l or less) crystalloids for resuscitation. Endpoints examined were mortality, measures of kidney function, serum chloride, hyperchloraemia/metabolic acidosis, blood transfusion volume, mechanical ventilation time, and length of hospital and intensive care unit stay. Risk ratios (RRs), mean differences (MDs) or standardized mean differences (SMDs) and confidence intervals were calculated using fixed-effect modelling. RESULTS: The search identified 21 studies involving 6253 patients. High-chloride fluids did not affect mortality but were associated with a significantly higher risk of acute kidney injury (RR 1.64, 95 per cent c.i. 1.27 to 2.13; P < 0.001) and hyperchloraemia/metabolic acidosis (RR 2.87, 1.95 to 4.21; P < 0.001). High-chloride fluids were also associated with greater serum chloride (MD 3.70 (95 per cent c.i. 3.36 to 4.04) mmol/l; P < 0.001), blood transfusion volume (SMD 0.35, 0.07 to 0.63; P = 0.014) and mechanical ventilation time (SMD 0.15, 0.08 to 0.23; P < 0.001). Sensitivity analyses excluding heavily weighted studies resulted in non-statistically significant effects for acute kidney injury and mechanical ventilation time. CONCLUSION: A weak but significant association between higher chloride content fluids and unfavourable outcomes was found, but mortality was unaffected by chloride content.

Evaluation of liver preservation solutions by using rats transgenic for luciferase.

INTRODUCTION: The solution in which graft tissue is stored (that is, preservation solution) is an important component of liver transplantation technology. Its protective effect is induced by substances in the solution, including radical scavengers, buffers, and energy-giving substances. New preservation solutions have proven to be effective in preventing organ damage during cold ischemia and in extending the time limits for storage. AIM: This study determined the relationship between luminescence intensity and content of adenosine triphosphate (ATP) in liver tissue and proposes a new ex vivo screening system that uses Lewis rats transgenic for luciferase for evaluating the effectiveness of preservation solutions. METHODS: Samples (diameter, 2 mm) of liver were obtained from transgenic rats. The viability of these tissues after storage for as long as 6 hours in University of Wisconsin (UW) solution, extracellular trehalose solution of Kyoto, Euro-Collins (EC) solution, histidine-tryptophan-ketoflutarate solution, low potassium dextran solution, or normal saline was assessed by determining ATP content and luminescence intensity. RESULTS: Luminescence had a linear relationship (R = 0.88) with ATP levels. Regardless of the preservation solution used, the luminescence intensities of the liver tissue chips decreased linearly with time especially through a short span of time (0 to 2 hours; R(2) = 0.58-1.0). The luminescence of liver chip tissues maintained long term (2 to 6 hours) in UW solution tended to be higher than those of tissues stored in other solutions (P < .05; 6 hours). On the basis of luminescence intensity, EC might be preferable to the other solutions tested for ultra-short-term storage (0.5 to 2 hours). CONCLUSION: Our model, which combines the use of the bioimaging system and Lewis rats transgenic for luciferase, effectively assessed the viability of liver tissue samples. We believe that this ex vivo screening system will be an effective tool for evaluating preservation solutions for liver grafts.

Marine therapy and its healing properties.

This study demonstrates the effects of Quinton's isotonic and hypertonic solution on mononuclear cells of peripheral blood. This involved assessing cell viability, morphology, number and size of aggregated cells; possible effects on cellular proliferation; effects on cellular proliferation in different lymphocyte populations; effect on hemoglobin released into the medium.

Characteristics of fluids used for intravascular volume replacement.

In this review, the relative merits of the different fluid solutions used for fluid replacement will be discussed. Differences in chemical composition may have important implications on volume expansion capacities but also on organ function. Among crystalloids, differences in electrolyte composition, and in particular chloride load, alter acid base status but may also affect other aspects of organ function. Large observational cohorts suggest that chloride load may be associated with a poor outcome. Colloids provide greater expansion capacities than crystalloids. When colloids are indicated, albumin should be preferred as it is the only one that has been proved to be safe in a large randomized trial. Cumulative evidence suggests that starches, even of the new generations, are associated with development of acute kidney injury. Hypertonic solutions may represent an interesting option in some groups of patients but more research is needed in this field.

Allogeneic human tissue-engineered blood vessel.

BACKGROUND: Arterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease; however, there is no available synthetic small-diameter vascular graft. METHODS: Tissue-engineered vessels were grown from human smooth muscle cells that were seeded on a biodegradable scaffold using a biomimetic perfusion system. The human tissue-engineered vessels (hTEV) were decellularized by a two-step process using a combination of detergents and hypertonic solutions. The mechanical characteristics were assessed by suture retention strength and burst pressure. The decellularized hTEV were implanted as aortic interpositional grafts in nude rats to evaluate in vivo performance as an arterial graft over a 6-week period. RESULTS: The human tissue-engineered structure formed a vessel composed of smooth muscle cells and the extracellular matrix proteins, including collagen. After decellularization, the collagen matrix remained intact while the cellular components were removed. The mechanical strength of the hTEV after decellularization was similar to human vein in vitro, with a burst pressure of 1,567 ± 384 mm Hg (n = 3) versus 1,680 ± 307 mm Hg for human saphenous vein. The hTEVs had a high patency rate (four of five grafts) without evidence of rupture or aneurysm over a 6-week period as an aortic interpositional graft in a nude rat model. Histologic analysis showed a thin neointima with a confluent endothelium and a subendothelial layer of smooth muscle cells on the explanted tissue-engineered vessels. Transmission electron microscopy on the explanted tissue demonstrated elastin formation in the neointima and intact residual collagen fibers from the tissue-engineered vessel. CONCLUSIONS: The hTEV had a high patency rate and remained mechanically stable as an aortic interpositional graft in a nude rat. The vessel supported the growth of a neointima with endothelial cells and smooth muscle cells. The host remodeling suggested the engineered matrix had a positive effect to create a regenerated vascular graft.

Short-term immunossupressive treatment of the donor does not prevent ischemia-reperfusion kidney damage in the rat.

INTRODUCTION: Ischemia-reperfusion (IR) kidney damage is an important factor for allograft survival in kidney transplantation. Recently it has been shown that immune factors from donor-derived cells are important in IR injury. The aim of this article was to evaluate the impact of short-term immunosuppressive treatment of the donor over a time frame relevant to cadaveric transplantation on IR damage to the rat kidney. METHODS: Male Sprague-Dawley rats served as donors and recipients. Three experimental groups were evaluated according to the donor treatment (n = 6); control (no treatment); sirolimus (1 mg/kg orally) or FTY720 (1 mg/kg intravenously) at 6 or 1 hours prior to left nephrectomy. Kidneys were flushed with cold Euro-Collins solution and after 2 hours transplanted using microsurgical techniques concomittant with a left nephrectomy. After 48 hours (day 0), we removed the right kidney. Serum creatinine (SCr) was determined daily thereafter as well as differential leukocyte counts prior to donor nephrectomy and sirolimus plasma levels thereafter. RESULTS: No difference was observed in SCr on day 1: control (3.97 ± 0.73 mg/dL), sirolimus (4.02 ± 1.44 mg/dL) and FTY 720 (3.27 ± 1.79 mg/dL; P = NS), or thereafter. Mortality was 50% in each group. Animals receiving FTY 720 showed a significant reduction in lymphocyte count (8.0 ± 3.1 to 1.1 ± 0.3 (P < .01). Sirolimus levels were 9.3 ± 1.5 ng/mL. CONCLUSION: We concluded that immunosuppressive treament of the donor within a time frame relevant to cadaveric kidney transplantation did not offer a benefit in terms of preventing IR injury.

Cryobiological properties of immature zebrafish oocytes assessed by their ability to be fertilized and develop into hatching embryos.

As a step to develop a cryopreservation method for zebrafish oocytes, we investigated the cryobiological properties of immature oocytes at stage III by examining their ability to mature and to develop into hatching embryos after fertilization. When oocytes were chilled at -5°C for 30min, the maturation rate decreased, but the rates of fertilization and hatching were not significantly different from those of controls. When oocytes were exposed to hypotonic solutions for 60min at 25°C, the rates of maturation, fertilization, and hatching decreased in a solution with 0.16Osm/kg or below. When oocytes were exposed to hypertonic solutions (containing sucrose) at 25°C for 30min, the maturation rate decreased in solution with 0.51Osm/kg, whereas the hatching rate decreased with lower osmolality (0.40Osm/kg). In an experiment on the toxicity of cryoprotectants (∼10%, at 25°C), it was found that glycerol and ethylene glycol were toxic both by the assessment of maturation and hatching. Propylene glycol, DMSO and methanol were less toxic by the assessment of maturation, but were found to be toxic by the assessment of hatching. Methanol was the least toxic, but it was less effective to make a solution vitrify than propylene glycol. Therefore, a portion of methanol was replaced with propylene glycol. The replacement increased the toxicity, but could be effective to reduce chilling injury at -5°C. These results clarified the sensitivity of immature oocytes to various cryobiological properties accurately, which will be useful for realizing cryopreservation of zebrafish oocytes.

Measurement of the membrane elasticity of red blood cell with osmotic pressure by optical tweezers.

Cells have to undergo many changes in osmotic pressure during their long-term preservation, and will have injuries before they return to their normal states. Mechanics of a cell with deformation, either small or large, is usually used to describe the change of the cell quantitatively. However, there are few reports on the deformation of cells subjected to the change of osmotic pressures during preservation. Here, we report our study of the elasticity of the human red blood cells under osmotic pressures using optical tweezers. We find that the deformation characteristics of erythrocytes are strongly dependent on the osmotic pressure. We also find the RBCs will become stiff with increasing osmotic pressure, suggesting a potential reason for membrane injury during preservation.

[Correction of intracranial hypertension syndrome using hyperosmolar solutions in patients with severe brain damage (multicenter randomized clinical study)].

The paper presents the results of a muticenter study of the effect of 3 hyperosmolar solutions (15% mannitol solution, 10% sodium chloride solution, and the combined solution HyperHAES containing 7.2% sodium chloride and hydroxyethyl starch 200/0.5) on the value of intracranial pressure (ICP) (invasive ICP monitoring) and systemic hemodynamic parameters (PiCCOplus) in 94 clinical cases of intracranial hypertension (ICP more than 20 mm Hg) in 25 patients with acute cerebral pathology (severe brain injury, aneurysmatic subarachnoid hemorrhage). Intravenous infusion of the solutions was found to induce a reduction in ICP; however, this was most pronounced (by 30-40%) and longer (up to 4 hours) when HyperHAES solution was used. This solution produced not only an osmotic, but also hemodynamic effect.

Ionic determinants of pH of acidic compartments under hypertonic conditions in trout hepatocytes.

Exposure of trout hepatocytes to hypertonicity induced a decrease in acridine orange (AO) fluorescence, indicating a corresponding decrease in pH inside the lumen of acidic compartments (pH(L)). Pre-exposure of cells to the specific V-ATPase inhibitor bafilomycin A1 (0.3 micromol l(-1)) increased AO fluorescence - unmasking H(+) leaks under steady-state conditions - and partially removed the hypertonicity-induced pH(L) decrease. The sustainability of the luminal acidification, but not the acidification itself, appeared to depend on a low K(+) and a high Cl(-) conductance under hypertonic conditions. Increasing K(+) conductance using the specific ionophore valinomycin (10 micromol l(-1)) or removal of extracellular Cl(-) after an instant drop in AO fluorescence resulted in a reversal of luminal acidity. The alkalinization measured under hypertonic conditions in the absence of Cl(-) was largely attenuated when cells were bathed in HCO(3)(-)-free medium, signifying the possible presence of Cl(-)/HCO(3)(-) exchange. Under steady-state conditions, while a slight and brief pH(L) increase was measured upon exposure of cells to valinomycin, Cl(-) removal, unexpectedly, induced a decrease in pH(L), indicating a role for extracellular Cl(-) in limiting luminal acidification. This was confirmed by the substantial pH(L) decrease measured upon exposure of cells to the anion exchanger inhibitor SITS (0.5 mmol l(-1)). Furthermore, hypertonicity-induced acidification was still noticeable in the presence of SITS. On the other hand, the hypertonicity-induced acidification was significantly reduced in the absence of extracellular Na(+) or Ca(2+). However, BAPTA-AM induced an increase in steady-state pH(L) that was independent of V-ATPase inhibition. Moreover, the BAPTA-induced alkalinization was still apparent after depletion of intracellular Ca(2+) using the Ca(2+) ionophore A23187 in Ca(2+)-free medium. We conclude that pH(L) of trout hepatocytes is sensitive to hypertonicity and ionic determinants of hypertonicity. Thus, changes in pH(L) should be considered when studying pH adaptations to hypertonic stress.

Erythrocyte storage in hypertonic (SAGM) or isotonic (PAGGSM) conservation medium: influence on cell properties.

BACKGROUND AND OBJECTIVES: Prolonged red blood cell (RBC) storage may be associated with increased post-transfusion morbidity and mortality. A contributing factor is RBC storage lesions. We analysed the role of additive conservation solutions, either hypertonic or isotonic, on such cell properties. MATERIALS AND METHODS: After blood donation in citrate-phosphate-dextrose as an anticoagulant, 10 RBC units were stored with saline-adenine-glucose-mannitol (SAGM; 376 mOsm/l) and 10 units with phosphate-adenine-glucose-guanosin-saline-mannitol (PAGGSM; 285 mOsm/l). Measurements were made on days 1 and 42 of storage. RESULTS: The mean cellular volume measured by centrifuged microhaematocrit increased from 87.6 +/- 3.1 fl to 100.7 +/- 4.3 fl in PAGGSM and to 92.2 +/- 2.5 fl in SAGM (P < 0.001) on day 1, after 42 days it was 95.8 +/- 4.0 fl and 93.8 +/- 3.9 fl, respectively. Spontaneous haemolysis and osmotic fragility were lower after storage in PAGGSM. Both additives showed a similar degree of echinocytosis, decreased RBC aggregability and deformability, and increased RBC suspension viscosity after storage. CONCLUSIONS: The isotonic PAGGSM prevented the initial RBC swelling caused by citrate-phosphate-dextrose less than hypertonic SAGM, but reduced the spontaneous haemolysis rate and osmotic fragility after 42 days of storage. All other parameters, such as echinocytosis, decreased RBC deformability and aggregability, and increased blood viscosity was similar for both additive solutions and remained a major problem of blood banking.

Protection of mitochondria during cold storage of liver and following transplantation: comparison of the two solutions, University of Wisconsin and Eurocollins.

Injury to allografts during ischaemia/reperfusion contribute to the development of graft failure following transplantation with significant morbidity and mortality to patients. The development of University of Wisconsin solution has significantly improved the quality of graft preservation and transplant outcome relative to formerly used solutions such as Eurocollins. The aim of this study was to further characterize mitochondrial structural and functional alterations occurring in rat livers following cold storage and transplantation. Mitochondrial impairment after prolonged storage in Eurocollins included decreased cyt. c+c1, cyt. b and cyt. a+a3 concentration and dramatic falls in the activities of the respiratory chain enzymes ubiquinol-cyt. c oxidoreductase and cytochrome oxidase. Under the same conditions the highest hydroperoxide but lowest vitamin E concentrations were also found. Although both the Eurocollins and University of Wisconsin preservation solutions have limitations in preventing oxidative injuries following cold storage and reperfusion, our data indicate that mitochondrial impairment was higher in Eurocollins- than in University of Wisconsin-stored livers. Further improvements are necessary in maintaining the stability of mitochondria in order to optimize preservations solutions used in transplantations.