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Previous studies have reported evidence of atrio-ventricular (AV) block in the oxygen-limited Trachemys scripta heart. However, if cardiac arrhythmia occurs in live turtles during prolonged anoxia exposure remains unknown. Here, we compare the effects of prolonged anoxic submergence and subsequent reoxygenation on cardiac electrical activity through in vivo electrocardiogram (ECG) recordings of 21 °C- and 5 °C-acclimated turtles to assess the prevalence of cardiac arrhythmia. Additionally, to elucidate the influence of extracellular conditions on the prominence of cardiac arrhythmia, we exposed spontaneously contracting T. scripta right atrium and electrically coupled ventricle strip preparations to extracellular conditions that sequentially and additively approximated the shift from the normoxic to anoxic extracellular condition of warm- and cold-acclimated turtles. Cardiac arrhythmia was prominent in 21 °C anoxic turtles. Arrhythmia was qualitatively evidenced by groupings of contractions in pairs and trios and quantified by an increased coefficient of variation of the RR interval. Similarly, exposure to combined anoxia, acidosis, and hyperkalemia induced arrhythmia in vitro that was not counteracted by hypercalcemia or combined hypercalcemia and heightened adrenergic stimulation. By comparison, cold acclimation primed the turtle heart to be resilient to cardiac arrhythmia. Although cardiac irregularities were present intermittently, no change in the variation of the RR interval occurred in vivo with prolonged anoxia exposure at 5 °C. Moreover, the in vitro studies at 5 °C highlighted the importance of adrenergic stimulation in counteracting AV block. Finally, at both acclimation temperatures, cardiac arrhythmia and irregularities ceased upon reoxygenation, indicating that the T. scripta heart recovers from anoxia-induced disruptions to cardiac excitation., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Jonathan Stecyk reports financial support was provided by 10.13039/100000001National Science Foundation. Jonathan Stecyk reports financial support was provided by 10.13039/100000002National Institutes of Health. Molly Garner reports financial support was provided by 10.13039/100000002National Institutes of Health. Diarmid Hall reports financial support was provided by 10.13039/100000002National Institutes of Health., (© 2022 The Authors.)

We indirectly assessed if altered transarcolemmal Ca 2+ flux accompanies the decreased cardiac activity displayed by Trachemys scripta with anoxia exposure and cold acclimation. Turtles were first acclimated to 21 °C or 5 °C and held under normoxic (21N; 5N) or anoxic conditions (21A; 5A). We then compared the response of intrinsic heart rate (f H ) and maximal developed force of spontaneously contracting right atria (F max,RA ), and maximal developed force of isometrically-contracting ventricular strips (F max,V ), to Ni 2+ (0.1-10 mM), which respectively blocks T-type Ca 2+ channels, L-type Ca 2+ channels and the Na + -Ca 2+ -exchanger at the low, intermediate and high concentrations employed. Dose-response curves were established in simulated in vivo normoxic (Sim Norm) or simulated in vivo anoxic extracellular conditions (Sim Anx; 21A and 5A preparations). Ni 2+ decreased intrinsic f H , F max,RA and F max,V of 21N tissues in a concentration-dependent manner, but the responses were blunted in 21A tissues in Sim Norm. Similarly, dose-response curves for F max,RA and F max,V of 5N tissues were right-shifted, whereas anoxia exposure at 5 °C did not further alter the responses. The influence of Sim Anx was acclimation temperature-, cardiac chamber- and contractile parameter-dependent. Combined, the findings suggest that: (1) reduced transarcolemmal Ca 2+ flux in the cardiac pacemaker is a potential mechanism underlying the slowed intrinsic f H of anoxic turtles at 21 °C, but not 5 °C, (2) a downregulation of transarcolemmal Ca 2+ flux may aid cardiac anoxia survival at 21 °C and prime the turtle myocardium for winter anoxia and (3) confirm that altered extracellular conditions with anoxia exposure can modify turtle cardiac transarcolemmal Ca 2+ flux., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Essential metals such as copper (Cu) and zinc (Zn) are important cofactors in diverse cellular processes, while metal imbalance may impact or be altered by disease state. Cu is essential for aerobic life with significant functions in oxidation-reduction catalysis. This redox reactivity requires precise intracellular handling and molecular-to-organismal levels of homeostatic control. As the central organ of Cu homeostasis in vertebrates, the liver has long been associated with Cu storage disorders including Wilson Disease (WD) (heritable human Cu toxicosis), Idiopathic Copper Toxicosis and Endemic Tyrolean Infantile Cirrhosis. Cu imbalance is also associated with chronic liver diseases that arise from hepatitis viral infection or other liver injury. The labile redox characteristic of Cu is often discussed as a primary mechanism of Cu toxicity. However, work emerging largely from the study of WD models suggests that Cu toxicity may have specific biochemical consequences that are not directly attributable to redox activity. This work reviews Cu toxicity with a focus on the liver and proposes that Cu accumulation specifically impacts Zn-dependent processes. The prospect that Cu toxicity has specific biochemical impacts that are not entirely attributable to redox may promote further inquiry into Cu toxicity in WD and other Cu-associated disorders.

Objective: We sought to use magnetic resonance (MR) imaging (MRI) to estimate percentage of fetal thorax occupied by lung, liver, and other abdominal organs in pregnancies with congenital diaphragmatic hernia (CDH)., Study Design: This was a retrospective study of pregnancies with isolated CDH referred for MRI between August 2000 and June 2006. Four regions of interest were measured in the axial plane by an investigator blinded to neonatal outcome, and volumes were then calculated. The percentages of thorax occupied by lung, liver, and all herniated organs were then compared with neonatal outcomes., Results: Fifteen CDH fetuses underwent MRI at a median gestational age of 29 weeks. Liver herniation was found in 93%. When the liver occupied > 20% of the fetal thorax, neonatal deaths were significantly increased. Percentages of lung and other herniated organs were not associated with outcome., Conclusion: In our MR series of isolated CDH, neonatal deaths were significantly increased when > 20% of the fetal thorax was occupied by liver.

Purpose: This study was performed to provide outcome data for the development of evidenced-based management techniques for children with appendicitis in the authors' hospital., Methods: This is a retrospective analysis of 1,196 consecutive children with appendicitis over a 5-year period (1996 to 2001) at a metropolitan hospital., Results: The median age was 9 years (7 months to 18 years). The perforation rate was 38.9%, and the nonappendicitis rate was 5.6%. Predictors of perforation included age less than 8 years, Hispanic ethnicity, generalized abdominal tenderness, rebound tenderness, and increased number of bands. In perforated cases, the median length of stay was 5 days, and the complication rate was 13.5%. There was no difference in complication rates related to type or timing of antibiotics or related to the individual surgeon. There was no difference in infection rates related to type of wound management., Conclusions: Children with perforated appendicitis are treated effectively by a less expensive broad-spectrum antibiotic regimen, expeditious operation by open or laparoscopic technique, primary wound closure, and postoperative intravenous antibiotics until they are afebrile for 24 hours and have a white blood cell count of less than 12,000/mm3. This approach is to be used in our prospective, randomized analysis of children treated on or off a clinical pathway.

The effect of exposure to a cat, as a predatory stressor, was examined in male and female rats during subsequent tests of amphetamine-induced stereotypy in which cat odors were present or absent. Rats in Group C/O were given a 15-min exposure session to a male cat while they were protected in a wire cage. They were then given an IP injection of d-amphetamine (1 mg/kg) and tested 30 min later for stereotypy in the presence of cat odors (soiled cat litter). Rats in Group NC/O were given a no-cat-exposure control session, and amphetamine tested with cat odors. Groups C/NO and NC/NO were both tested without cat odors (fresh litter), with the former group having been previously exposed to a cat. During the 90-min test sessions, female rats showed significantly more stereotypy than males. More importantly, the male subjects in group C/O exhibited significantly more stereotypy than the males in the other groups, and group NC/NO males showed the least amount of stereotypy. These findings clearly indicate that amphetamine reactivity is influenced by prior exposure to a predator, the presence of predatory odors during testing, and the subject's sex.