Maximum Running Speed of Captive Bar-Headed Geese Is Unaffected by Severe Hypoxia

While bar-headed geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed geese and barnacle geese (a low altitude species) during exercise in hypoxia. Bar-headed geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min�1. Barnacle geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min�1) was significantly lower than bar-headed geese. In bar-headed geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare

A dedicated haem lyase is required for the maturation of a novel bacterial cytochrome c with unconventional covalent haem binding

In bacterial c-type cytochromes, the haem cofactor is covalently attached via two cysteine residues organized in a haem c-binding motif. Here, a novel octa-haem c protein, MccA, is described that contains only seven conventional haem c-binding motifs (CXXCH), in addition to several single cysteine residues and a conserved CH signature. Mass spectrometric analysis of purified MccA from Wolinella succinogenes suggests that two of the single cysteine residues are actually part of an unprecedented CX15CH sequence involved in haem c binding. Spectroscopic characterization of MccA identified an unusual high-potential haem c with a red-shifted absorption maximum, not unlike that of certain eukaryotic cytochromes c that exceptionally bind haem via only one thioether bridge. A haem lyase gene was found to be specifically required for the maturation of MccA in W. succinogenes. Equivalent haem lyase-encoding genes belonging to either the bacterial cytochrome c biogenesis system I or II are present in the vicinity of every known mccA gene suggesting a dedicated cytochrome c maturation pathway. The results necessitate reconsideration of computer-based prediction of putative haem c-binding motifs in bacterial proteomes

The Qo site of the mitochondrial complex III is required for the transduction of hypoxic signaling via reactive oxygen species production

Mammalian cells increase transcription of genes for adaptation to hypoxia through the stabilization of hypoxia-inducible factor 1α (HIF-1α) protein. How cells transduce hypoxic signals to stabilize the HIF-1α protein remains unresolved. We demonstrate that cells deficient in the complex III subunit cytochrome b, which are respiratory incompetent, increase ROS levels and stabilize the HIF-1α protein during hypoxia. RNA interference of the complex III subunit Rieske iron sulfur protein in the cytochrome b–null cells and treatment of wild-type cells with stigmatellin abolished reactive oxygen species (ROS) generation at the Qo site of complex III. These interventions maintained hydroxylation of HIF-1α protein and prevented stabilization of HIF-1α protein during hypoxia. Antioxidants maintained hydroxylation of HIF-1α protein and prevented stabilization of HIF-1α protein during hypoxia. Exogenous hydrogen peroxide under normoxia prevented hydroxylation of HIF-1α protein and stabilized HIF-1α protein. These results provide genetic and pharmacologic evidence that the Qo site of complex III is required for the transduction of hypoxic signal by releasing ROS to stabilize the HIF-1α protein

Symptoms of anxiety and depression in school-aged children with active epilepsy: A population-based study

Children (5-15 years) with active epilepsy were screened using the parent-report (n=69) and self-report (n=48) versions of the Spence Children's Anxiety Scale (SCAS) and the self-report version of the Children's Depression Inventory (CDI) (n=48) in a population-based sample. A total of 32.2% of children (self-report) and 15.2% of children (parent-report) scored ≥1 SD above the mean on the SCAS total score. The subscales where most difficulty were reported on parent-report were Physical Injury and Separation Anxiety. There was less variation on self-report. On the CDI, 20.9% of young people scored ≥1 SD above the mean. Children reported significantly more symptoms of anxiety on the SCAS total score and three of the subscales (p<.05). There was a significant effect on the SCAS total score of respondents by seizure type interaction, suggesting higher scores on SCAS for children with generalized seizures on self- but not parent-report. Higher CDI scores were significantly associated with generalized seizures (p>.05).Symptoms of anxiety were more common based on self-report compared with parent-report. Children with generalized seizures reported more symptoms of depression and anxiety

Child and parental sleep in young children with epilepsy: A population-based case-control study

Objective: To determine the prevalence of parent‐reported sleep problems in young children with epilepsy and their parents, and to compare findings with those in a non–epilepsy‐related neurodisability (neurodevelopmental/neurological difficulties) group. Method: Parents of young children (1–7 years) with epilepsy (n = 48 [91% ascertainment]) completed the Child Sleep Habits Questionnaire (CSHQ). Parents (mothers and fathers) also completed the Pittsburgh Sleep Quality Index (PSQI) and the Iowa Fatigue Scale (IFS) in relation to their own functioning. The responses of parents of children with epilepsy were compared with parents of developmental‐, age‐, and gender‐matched children with nonepilepsy‐related neurodisability (n = 48). Results: There was not a significant difference in the proportion of children with epilepsy and the children with neurodisability scoring in the at‐risk range on the CSHQ (81% vs. 71% respectively) (p = 0.232). 62% of mothers and 44% of fathers of children with epilepsy had ‘poor quality sleep’ on the PSQI; there was not a significant difference between mothers of children with epilepsy and those of children with neurodisability (p = 0.526) or IFS (p = 0.245) total scores. However, mothers of children with epilepsy had significantly more difficulties on the productivity subscale of the IFS (p = 0.004). There were no significant differences between fathers’ scores on either measure. In the epilepsy group, child behavioral problems (p = 0.001) were independently associated with child sleep difficulties and maternal mental health problems were associated with parental sleep difficulties (p = 0.04) and fatigue (p = 0.018). Significance: Young children with epilepsy and their parents have a high rate of sleep difficulties. There is a need to develop effective interventions for this population, taking into consideration of the role of child behavioral problems and parental mental health difficulties

Linear ubiquitin assembly complex regulates lung epithelial–driven responses during influenza infection

Influenza A virus (IAV) is among the most common causes of pneumonia-related death worldwide. Pulmonary epithelial cells are the primary target for viral infection and replication and respond by releasing inflammatory mediators that recruit immune cells to mount the host response. Severe lung injury and death during IAV infection result from an exuberant host inflammatory response. The linear ubiquitin assembly complex (LUBAC), composed of SHARPIN, HOIL-1L, and HOIP, is a critical regulator of NF-κB–dependent inflammation. Using mice with lung epithelial–specific deletions of HOIL-1L or HOIP in a model of IAV infection, we provided evidence that, while a reduction in the inflammatory response was beneficial, ablation of the LUBAC-dependent lung epithelial–driven response worsened lung injury and increased mortality. Moreover, we described a mechanism for the upregulation of HOIL-1L in infected and noninfected cells triggered by the activation of type I IFN receptor and mediated by IRF1, which was maladaptive and contributed to hyperinflammation. Thus, we propose that lung epithelial LUBAC acts as a molecular rheostat that could be selectively targeted to modulate the immune response in patients with severe IAV-induced pneumonia.Fil: Brazee, Patricia L.. Northwestern University; Estados UnidosFil: Morales Nebreda, Luisa. Northwestern University; Estados UnidosFil: Magnani, Natalia Daniela. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Garcia, Joe G. N.. University of Arizona; Estados UnidosFil: Misharin, Alexander V.. Northwestern University; Estados UnidosFil: Ridge, Karen M.. Northwestern University; Estados UnidosFil: Budinger, G.R. Scott. Northwestern University; Estados UnidosFil: Iwai, Kazuhiro. Kyoto University; JapónFil: Dada, Laura Andrea. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Sznajder, Jacob I.. Northwestern University; Estados Unido

Guidelines for Perioperative Care for Liver Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations 2022.

Enhanced Recovery After Surgery (ERAS) has been widely applied in liver surgery since the publication of the first ERAS guidelines in 2016. The aim of the present article was to update the ERAS guidelines in liver surgery using a modified Delphi method based on a systematic review of the literature. A systematic literature review was performed using MEDLINE/PubMed, Embase, and the Cochrane Library. A modified Delphi method including 15 international experts was used. Consensus was judged to be reached when >80% of the experts agreed on the recommended items. Recommendations were based on the Grading of Recommendations, Assessment, Development and Evaluations system. A total of 7541 manuscripts were screened, and 240 articles were finally included. Twenty-five recommendation items were elaborated. All of them obtained consensus (>80% agreement) after 3 Delphi rounds. Nine items (36%) had a high level of evidence and 16 (64%) a strong recommendation grade. Compared to the first ERAS guidelines published, 3 novel items were introduced: prehabilitation in high-risk patients, preoperative biliary drainage in cholestatic liver, and preoperative smoking and alcohol cessation at least 4 weeks before hepatectomy. These guidelines based on the best available evidence allow standardization of the perioperative management of patients undergoing liver surgery. Specific studies on hepatectomy in cirrhotic patients following an ERAS program are still needed

Imaging cortical dynamics in GCaMP transgenic rats with a head-mounted widefield macroscope

Widefield imaging of calcium dynamics is an emerging method for mapping regional neural activity but is currently limited to restrained animals. Here we describe cScope, a head- mounted widefield macroscope developed to image large-scale cortical dynamics in rats during natural behavior. cScope provides a 7.8 by 4 mm field of view, dual illumination paths for both fluorescence and hemodynamic correction, and can be fabricated at low cost using readily attainable components. We also report the development of Thy-1 transgenic rat strains with widespread neuronal expression of the calcium indicator GCaMP6f. We combined these two technologies to image large-scale calcium dynamics in the dorsal neocortex during a visual evidence accumulation task. Quantitative analysis of task-related dynamics revealed multiple regions having neural signals that encode behavioral choice and sensory evidence. Our results provide a new transgenic resource for calcium imaging in rats and extend the domain of headmounted microscopes to larger-scale cortical dynamics.Accepted manuscrip

Dentate gyrus progenitor cell proliferation after the onset of spontaneous seizures in the tetanus toxin model of temporal lobe epilepsy.

Temporal lobe epilepsy alters adult neurogenesis. Existing experimental evidence is mainly from chronic models induced by an initial prolonged status epilepticus associated with substantial cell death. In these models, neurogenesis increases after status epilepticus. To test whether status epilepticus is necessary for this increase, we examined precursor cell proliferation and neurogenesis after the onset of spontaneous seizures in a model of temporal lobe epilepsy induced by unilateral intrahippocampal injection of tetanus toxin, which does not cause status or, in most cases, detectable neuronal loss. We found a 4.5 times increase in BrdU labeling (estimating precursor cells proliferating during the 2nd week after injection of toxin and surviving at least up to 7days) in dentate gyri of both injected and contralateral hippocampi of epileptic rats. Radiotelemetry revealed that the rats experienced 112±24 seizures, lasting 88±11s each, over a period of 8.6±1.3days from the first electrographic seizure. On the first day of seizures, their duration was a median of 103s, and the median interictal period was 23min, confirming the absence of experimentally defined status epilepticus. The total increase in cell proliferation/survival was due to significant population expansions of: radial glial-like precursor cells (type I; 7.2×), non-radial type II/III neural precursors in the dentate gyrus stem cell niche (5.6×), and doublecortin-expressing neuroblasts (5.1×). We conclude that repeated spontaneous brief temporal lobe seizures are sufficient to promote increased hippocampal neurogenesis in the absence of status epilepticus