Peroxynitrite-induced mitochondrial and endonuclease-mediated nuclear DNA damage in acetaminophen hepatotoxicity

Intracellular sources of peroxynitrite formation and potential targets for this powerful oxidant and nitrating agent have not been identified after acetaminophen (AAP) overdose. Therefore, we tested the hypothesis that peroxynitrite generated in mitochondria may be responsible for mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damage. C3Heb/FeJ mice were treated with 300 mg/kg AAP and monitored for up to 12 h. Loss of mtDNA (assayed by slot blot hybridization) and substantial nDNA fragmentation (evaluated by anti-histone enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and agarose gel electrophoresis) were observed as early as 3 h after AAP overdose. Analysis of nitrotyrosine protein adducts in subcellular fractions established that peroxynitrite was generated predominantly in mitochondria beginning at 1 h after AAP injection. Delayed treatment with a bolus dose of glutathione (GSH) accelerated the recovery of mitochondrial glutathione, which then effectively scavenged peroxynitrite. However, mtDNA loss was only partially prevented. Despite the absence of nitrotyrosine adducts in the nucleus after AAP overdose, nDNA damage was almost completely eliminated with GSH administration. A direct comparison of nDNA damage after AAP overdose with nDNA fragmentation during tumor necrosis factor receptor-mediated apoptosis showed similar DNA ladders on agarose gels but quantitatively different results in three other assays. We conclude that peroxynitrite may be partially responsible for mtDNA loss but is not directly involved in nDNA damage. In contrast, nDNA fragmentation after AAP overdose is not caused by caspase-activated DNase but most likely by other intracellular DNase(s), whose activation is dependent on the mitochondrial oxidant stress and peroxynitrite formation.     

Loss of SMARCE1 expression is a specific diagnostic marker of clear cell meningioma: a comprehensive immunophenotypical and molecular analysis

Clear cell meningioma (CCM) is a rare grade II histopathological subtype that usually occurs in young patients and displays high recurrence rate. Germline SMARCE1 mutations have been described in hereditary forms of this disease and more recently in small syndromic and sporadic CCM series. The diagnostic value of SMARCE1 in distinguishing between CCM and other meningioma variants has not been yet established. The aim of our study was to investigate the status of SMARCE1 in a series of CCMs and its morphological mimickers. We compared the performance of an anti‐SMARCE1 antibody and the molecular analysis of the SMARCE1 gene in a retrospective multicenter series of CCMs. All CCMs lossed SMARCE1 immunoexpression. Bi‐allelic inactivating events were found by NGS‐based sequencing in all of these cases, except for one, which was incompletely explored, but had a wild‐type sequence. We then validated the anti‐SMARCE1 antibody specificity by analyzing additional 305 pediatric and adult meningiomas of various subtypes and 15 non‐meningioma clear cell tumors by SMARCE1 immunohistochemistry. A nuclear immunostaining was preserved in all other meningioma variants, as well as non‐meningioma clear cell tumors. In conclusion, our series showed, for the first time, that SMARCE1 immunostaining is a highly sensitive biomarker for CCM, useful as a routine diagnostic biomarker.     

Identification of Ventricular Tachycardia of Epicardial Origin from Unipolar Potentials Obtained at the Endocardial Surface: Is It Feasible?

VT late after myocardial infarction usually originates from the endocardial surface; subepicardial substrates are also possible. The identification of these atypical locations with endocardial mapping remains unresolved even with new mapping technologies. This study compared isopotential maps, signal morphology, and activation patterns around left endocardial breakthroughs recorded in VTs originating from the subepicardium or subendocardium after remote myocardial infarction. These results were extracted from a database of 111 tachycardias obtained at surgery in 34 patients. Mapping was performed with a 128-unipolar electrode system using an epicardial mesh and a left ventricular endocardial balloon. Subepicardial (n = 7) and subendocardial VTs (n = 10) were defined as complete superficial reentry and/or as tachycardias with a > or = 25-ms delay between the earliest activity and the breakthrough of activation on the opposite surface. A positive potential distribution covering the area of initial endocardial activity was observed in a single subepicardial VT but in none of the subendocardial ones (P = NS). R waves were observed on the earliest endocardial unipolar signals in two subepicardial VTs and five subendocardial VTs (P = NS). The area covered by the first 5-ms or 10-ms isochrone at the endocardial level was larger in subepicardial VTs than in subendocardial VTs but the difference was not significant. In conclusion, despite a wider endocardial area of early activity in VTs of subepicardial origin, no reliable criteria can be proposed to identify these tachycardias from mapping data restricted to the endocardial surface. This is probably due to highly nonuniform anisotropic propagation around the scarred tissue.     

Phase III randomized study comparing 5 or 10 microg per kg per day of filgrastim for mobilization of peripheral blood progenitor cells with chemotherapy,followed by intensification and autologous transplantation in patients with nonmyeloid malignancies

BACKGROUND: It is not known whether increasing the dose of filgrastim after mobilizing chemotherapy improves collection of peripheral blood progenitor cells (PBPC) and leads to faster hematopoietic engraftment after autologous transplantation. STUDY DESIGN AND METHODS: A randomized, open-label, multicenter trial was carried out in patients with breast cancer, multiple myeloma, and lymphoma, in which patients were randomized to receive 5 or 10 microg per kg per day of filgrastim after standard chemotherapy to mobilize PBPCs. After high-dose chemotherapy, the components from the first two leukapheresis procedures were returned, and all patients received 5 microg per kg day of filgrastim after transplantation. RESULTS: A total of 131 patients were randomized, of whom 128 were mobilized (Group A, 5 microg/kg, n = 66; Group B, 10 microg/kg, n = 62) and 112 were transplanted. Only six patients were not transplanted because of insufficient CD34+ cell numbers. The median number of CD34+ cells collected in the first two leukapheresis procedures tended to be higher in Group B than in Group A (12.0 vs. 7.2 x 10(6)/kg, NS), but after transplantation there was no significant difference in median times to platelet (9 days in both groups) or neutrophil (8 days in both groups) engraftment or the number of platelet transfusions (three in both groups). A subsequent subgroup analysis separating patients transplanted after first- or second-line chemotherapy also showed no measurable impact of filgrastim dose on the median CD34+ cell yield or on platelet engraftment in either subgroup. CONCLUSION: PBPC mobilization with chemotherapy and 5 microg per kg of filgrastim is very efficient, and 10 microg per kg of filgrastim does not provide additional clinical benefit.     

Phenotype in girls and women with Turner syndrome: Association between dysmorphic features,karyotype and cardio-aortic malformations

Introduction

Turner syndrome (TS) is a genetic disorder characterized by the (partial) absence or a structural aberration of the second sex chromosome and is associated with a variety of phenotypes with specific physical features and cardio-aortic malformations. The objective of this study was to gain a better insight into the differences in dysmorphic features between girls and women with TS and to explore the association between these features, karyotype and cardio-aortic malformations.

Crossover Sexual Offenses

Crossover sexual offenses are defined as those in which victims are from multiple age, gender, and relationship categories. This study investigates admissions of crossover sexual offending from sex offenders participating in treatment who received polygraph testing. For 223 incarcerated and 266 paroled sexual offenders, sexual offenses were recorded from criminal history records and admissions during treatment coupled with polygraph testing. The majority of incarcerated offenders admitted to sexually assaulting both children and adults from multiple relationship types. In addition, there was a substantial increase in offenders admitting to sexually assaulting victims from both genders. In a group of incarcerated offenders who sexually assaulted children, the majority of offenders admitted to sexually assaulting both relatives and nonrelatives, and there was a substantial increase in the offenders admitting to assaulting both male and female children. Although similar trends were observed for the sample of parolees, the rates were far less dramatic. Parolees appeared to have greater levels of denial, had participated in fewer treatment sessions, and perceived greater supervision restrictions as a result of admitting additional offenses. These findings support previous research indicating that many sexual offenders do not exclusively offend against a preferred victim type.     

Building trophic specializations that result in substantial niche partitioning within a young adaptive radiation

Dietary partitioning often accompanies the increased morphological diversity seen during adaptive radiations within aquatic systems. While such niche partitioning would be expected in older radiations, it is unclear how significant morphological divergence occurs within a shorter time period. Here we show how differential growth in key elements of the feeding mechanism can bring about pronounced functional differences among closely related species. An incredibly young adaptive radiation of three Cyprinodon species residing within hypersaline lakes in San Salvador Island, Bahamas, has recently been described. Characterized by distinct head shapes, gut content analyses revealed three discrete feeding modes in these species: basal detritivory as well as derived durophagy and lepidophagy (scale‐feeding). We dissected, cleared and stained, and micro‐CT scanned species to assess functionally relevant differences in craniofacial musculoskeletal elements. The widespread feeding mode previously described for cyprinodontiforms, in which the force of the bite may be secondary to the requisite dexterity needed to pick at food items, is modified within both the scale specialist and the durophagous species. While the scale specialist has greatly emphasized maxillary retraction, using it to overcome the poor mechanical advantage associated with scale‐eating, the durophage has instead stabilized the maxilla. In all species the bulk of the adductor musculature is composed of AM A1. However, the combined masses of both adductor mandibulae (AM) A1 and A3 in the scale specialist were five times that of the other species, showing the importance of growth in functional divergence. The scale specialist combines plesiomorphic jaw mechanisms with both a hypertrophied AM A1 and a slightly modified maxillary anatomy (with substantial functional implications) to generate a bite that is both strong and allows a wide range of motion in the upper jaw, two attributes that normally tradeoff mechanically. Thus, a significant feeding innovation (scale‐eating, rarely seen in fishes) may evolve based largely on allometric changes in ancestral structures. Alternatively, the durophage shows reduced growth with foreshortened jaws that are stabilized by an immobile maxilla. Overall, scale specialists showed the most divergent morphology, suggesting that selection for scale‐biting might be stronger or act on a greater number of traits than selection for either detritivory or durophagy. The scale specialist has colonized an adaptive peak that few lineages have climbed. Thus, heterochronic changes in growth can quickly produce functionally relevant change among closely related species.     

Larval Echinococcus multilocularis infection reduces dextran sulphate sodium‐induced colitis in mice by attenuating T helper type 1/type 17‐mediated immune reactions

The tumour‐like growth of larval Echinococcus multilocularis tissue (causing alveolar echinococcosis, AE) is directly linked to the nature/orientation of the periparasitic host immune‐mediated processes. Parasite‐mediated immune suppression is a hallmark triggering infection outcome in both chronic human and murine AE. So far, little is known about secondary systemic immune effects of this pathogen on other concomitant diseases, e.g. endogenous gut inflammation. We examined the influence of E. multilocularis infection on murine dextran sodium sulphate (DSS) ‐induced colitis. At 3 months after E. multilocularis infection (chronic stage), the mice were challenged with 3% DSS in the drinking water for 5 days plus subsequently with tap water (alone) for another 4 days. After necropsy, fixed tissues/organs were sectioned and stained with haematoxylin & eosin for assessing inflammatory reactions. Cytokine levels were measured by flow cytometry and quantitative RT‐PCR. Colitis severity was assessed (by board‐certified veterinary pathologists) regarding (i) colon length, (ii) weight loss and (iii) a semi‐quantitative score of morphological changes. The histopathological analysis of the colon showed a significant reduction of DSS‐induced gut inflammation by concomitant E. multilocularis infection, which correlated with down‐regulation of T helper type 1 (Th1)/Th17 T‐cell responses in the colon tissue. Echinococcus multilocularis infection markedly reduced the severity of DSS‐induced gut inflammation upon down‐regulation of Th1/Th17 cytokine expression and attenuation of CD11b⁺ cell activation. In conclusion, E. multilocularis infection remarkably reduces DSS‐induced colitis in mice by attenuating Th1/Th17‐mediated immune reactions.     

Erythromycin and early enteral nutrition in mechanically ventilated patients

OBJECTIVE: To determine whether erythromycin facilitates early enteral nutrition in mechanically ventilated, critically ill patients. DESIGN: Prospective, randomized, placebo-controlled, single-blind trial. SETTING: General intensive care unit in a university-affiliated general hospital. PATIENTS: Forty consecutive critically ill patients receiving invasive mechanical ventilation and early nasogastric feeding. INTERVENTIONS: Patients were assigned randomly to intravenous erythromycin (250 mg/6 hrs; n = 20) or a placebo (intravenous 5% dextrose, 50 mL/6 hrs; n = 20) for 5 days. The first erythromycin or 5% dextrose injection was given at 8 am on the day after intubation. One hour later, a daily 18-hr enteral nutrition regimen via a 14-Fr gastric tube was started. Residual gastric volume was aspirated and measured every day at 9 am, 3 pm, 9 pm, and 3 am. Enteral nutrition was discontinued if residual gastric volume exceeded 250 mL or the patient vomited. MEASUREMENTS AND MAIN RESULTS: On the first day, residual gastric volume was smaller in the erythromycin than in the placebo group (3 pm, 15 +/- 7 mL vs. 52 +/- 14 mL, p <.05; 9 pm, 29 +/- 15 mL vs. 100 +/- 20 mL, p <.001; 3 am, 11 +/- 4 mL vs. 54 +/- 13 mL, p <.05). With erythromycin, residual gastric volume at 9 pm was smaller on the second day (33 +/- 11 mL vs. 83 +/- 19 mL, p <.01) and residual gastric volume at 3 pm was smaller on the third day (39 +/- 15 mL vs. 88 +/- 19 mL, p <.05) than with placebo. On the fourth and fifth days, the differences in residual gastric volume were not significant. Enteral nutrition was discontinued before the end of the 5-day period in seven of the 20 erythromycin patients and 14 of the 20 placebo patients (p <.001). CONCLUSION: In critically ill patients receiving invasive mechanical ventilation, erythromycin promotes gastric emptying and improves the chances of successful early enteral nutrition.