The Banff working group on preimplantation biopsy was established to develop consensus criteria (best practice guidelines) for the interpretation of preimplantation kidney biopsies. Digitally scanned slides were used (i) to evaluate interobserver variability of histopathologic findings, comparing frozen sections with formalin‐fixed, paraffin‐embedded tissue of wedge and needle core biopsies, and (ii) to correlate consensus histopathologic findings with graft outcome in a cohort of biopsies from international medical centers. Intraclass correlations (ICCs) and univariable and multivariable statistical analyses were performed. Good to fair reproducibility was observed in semiquantitative scores for percentage of glomerulosclerosis, arterial intimal fibrosis and interstitial fibrosis on frozen wedge biopsies. Evaluation of frozen wedge and core biopsies was comparable for number of glomeruli, but needle biopsies showed worse ICCs for glomerulosclerosis, interstitial fibrosis and tubular atrophy. A consensus evaluation form is provided to help standardize the reporting of histopathologic lesions in donor biopsies. It should be recognized that histologic parameters may not correlate with graft outcome in studies based on organs deemed to be acceptable after careful clinical assessment. Significant limitations remain in the assessment of implantation biopsies.

Chronic iron overload has slow and insidious effects on heart, liver, and other organs. Because iron-driven oxidation of most biologic materials (such as lipids and proteins) is readily repaired, this slow progression of organ damage implies some kind of biological "memory." We hypothesized that cumulative iron-catalyzed oxidant damage to mtDNA might occur in iron overload, perhaps explaining the often lethal cardiac dysfunction. Real time PCR was used to examine the "intactness" of mttDNA in cultured H9c2 rat cardiac myocytes. After 3-5 days exposure to high iron, these cells exhibited damage to mtDNA reflected by diminished amounts of near full-length 15.9-kb PCR product with no change in the amounts of a 16.1-kb product from a nuclear gene. With the loss of intact mtDNA, cellular respiration declined and mRNAs for three electron transport chain subunits and 16 S rRNA encoded by mtDNA decreased, whereas no decrements were found in four subunits encoded by nuclear DNA. To examine the importance of the interactions of iron with metabolically generated reactive oxygen species, we compared the toxic effects of iron in wild-type and rho o cells. In wild-type cells, elevated iron caused increased production of reactive oxygen species, cytostasis, and cell death, whereas the rho o cells were unaffected. We conclude that long-term damage to cells and organs in iron-overload disorders involves interactions between iron and mitochondrial reactive oxygen species resulting in cumulative damage to mtDNA, impaired synthesis of respiratory chain subunits, and respiratory dysfunction.Patients with primary or secondary iron overload are liable to cardiac and hepatic failure, and type II diabetes. Iron is required for the activity of numerous iron-and heme-containing proteins, but "free" (i.e. redox active) iron catalyzes the formation of highly toxic reactive oxygen species (ROS) 2 that damage lipids, proteins, and DNA (1). This damage is assumed to arise from iron-catalyzed hydroxyl radical formation or, perhaps more likely, iron-centered radicals such as ferryl and perferryl (2, 3). Iron-driven oxidation events require that the metal interact with cellular oxidizing and reducing equivalents such as superoxide and hydrogen peroxide, a major source of which is "leak" of electrons from the mitochondrial electron transport chain (4 -6).The present investigations were focused on the etiology of iron-mediated cardiac damage and specifically on the question of why, in patients with chronic iron overload, damage to organs such as the heart develops over a period of years, whereas most types of iron-mediated oxidation events can be repaired within minutes or hours. We have investigated the hypothesis that cumulative damage to DNA, specifically mtDNA, is critical to the slow development of cardiac dysfunction in chronic iron overload. In partial support of this idea, earlier studies clearly show that iron does promote DNA base oxidation as well as single and double strand DNA breaks. Mitochondrial DNA may be particularly vulnerable ...

Oxygen is critical to aerobic metabolism, but excessive oxygen (hyperoxia) causes cell injury and death. An oxygen-tolerant strain of HeLa cells, which proliferates even under 80% O 2 , termed "HeLa-80," was derived from wild-type HeLa cells ("HeLa-20") by selection for resistance to stepwise increases of oxygen partial pressure. Surprisingly, antioxidant defenses and susceptibility to oxidant-mediated killing do not differ between these two strains of HeLa cells. However, under both 20 and 80% O 2 , intracellular reactive oxygen species (ROS) production is significantly (ϳ2-fold) less in HeLa-80 cells. In both cell lines the source of ROS is evidently mitochondrial. Although HeLa-80 cells consume oxygen at the same rate as HeLa-20 cells, they consume less glucose and produce less lactic acid. Most importantly, the oxygen-tolerant HeLa-80 cells have significantly higher cytochrome c oxidase activity (ϳ2-fold), which may act to deplete upstream electron-rich intermediates responsible for ROS generation. Indeed, preferential inhibition of cytochrome c oxidase by treatment with n-methyl protoporphyrin (which selectively diminishes synthesis of heme a in cytochrome c oxidase) enhances ROS production and abrogates the oxygen tolerance of the HeLa-80 cells. Thus, it appears that the remarkable oxygen tolerance of these cells derives from tighter coupling of the electron transport chain.Oxygen is crucial to aerobic metabolism, but excess oxygen or, more likely, reactive oxygen species (ROS) 1 generated under hyperoxic conditions, will cause cell injury and death. Damage to cells and tissues caused by hyperoxia is clinically important. For example, both lung damage and retrolental fibroplasia occur in premature infants given oxygen as therapy for pulmonary insufficiency. The risk of these complications is further amplified by the immaturity of cellular antioxidant defenses in premature infants (1). Similar pulmonary damage is also observed in adults who, on prolonged exposure to high partial pressures of inhaled O 2 , exhibit cough, shortness of breath, decreased vital capacity, and increased alveolar-capillary permeability (2-4).Despite decades of work, it is still not known precisely how hyperoxia causes damage to cells and tissues. Nonetheless, it is commonly believed that free radicals play a key role in the pathophysiology of oxygen toxicity and cellular damage is probably mediated by increased production of ROS (5). This excessive production of ROS likely derives from the mitochondria that, under conditions of high oxygen, exhibit increased electron leak from the electron transport chain (5-7). We have approached the question of the nature of hyperoxic cell damage using a special line of HeLa cells selected for resistance to stepwise increases in the partial pressure of O 2 . These oxygentolerant HeLa cells are able to survive and grow under 80% O 2 , a partial pressure of oxygen under which normal HeLa cells and most other mammalian cells not only stop growing but die (8).If enhanced ROS production is, in fact, a...

Background & Aims: Few studies have compared regional differences in acute pancreatitis. We analyzed data from an international registry of patients with acute pancreatitis to evaluate geographic variations in patient characteristics, management, and outcomes. Methods: We collected data from the APPRENTICE registry of patients with acute pancreatitis, which obtains information from patients in Europe (6 centers), India (3 centers), Latin America (5 centers), and North America (8 centers) using standardized questionnaires. Our final analysis included 1,612 patients with acute pancreatitis (median age, 49 years; 53% male, 62% white) enrolled from August 2015 through January 2018. Results: Biliary (45%) and alcoholic acute pancreatitis (21%) were the most common etiologies. Based on the revised Atlanta classification, 65% of patients developed mild disease, 23% moderate, and 12% severe. The mean age of patients in Europe (58 years) was older than mean age for all 4 regions (46 years) and a higher proportion of patients in Europe had comorbid conditions (73% vs 50% overall). The predominant etiology of acute pancreatitis in Latin America was biliary (78%), whereas alcohol-associated pancreatitis accounted for the highest proportion of acute pancreatitis cases in India (45%). Pain was managed with opioid analgesics in 93% of patients in North America versus 27% of patients in the other 3 regions. Cholecystectomies were performed at the time of hospital admission for most patients in Latin America (60% vs 15% overall). A higher proportion of European patients with severe acute pancreatitis died during the original hospital stay (44%) compared with the other 3 regions (15%). 8 Conclusions: We found significant variation in demographics, etiologies, management practices, and outcomes of acute pancreatitis worldwide.