Depressed myocardial cross-bridge cycling kinetics in a female guinea pig model of diastolic heart failure.

Cardiac hypertrophy is associated with diastolic heart failure (DHF), a syndrome in which systolic function is preserved but cardiac filling dynamics are depressed. The molecular mechanisms underlying DHF and the potential role of altered cross-bridge cycling are poorly understood. Accordingly, chronic pressure overload was induced by surgically banding the thoracic ascending aorta (AOB) in ∼400 g female Dunkin Hartley guinea pigs (AOB); Sham-operated age-matched animals served as controls. Guinea pigs were chosen to avoid the confounding impacts of altered myosin heavy chain (MHC) isoform expression seen in other small rodent models. In vivo cardiac function was assessed by echocardiography; cardiac hypertrophy was confirmed by morphometric analysis. AOB resulted in left ventricle (LV) hypertrophy and compromised diastolic function with normal systolic function. Biochemical analysis revealed exclusive expression of ß-MHC isoform in both sham control and AOB LVs. Myofilament function was assessed in skinned multicellular preparations, skinned single myocyte fragments, and single myofibrils prepared from frozen (liquid N2) LVs. The rates of force-dependent ATP consumption (tension-cost) and force redevelopment (Ktr), as well as myofibril relaxation time (Timelin) were significantly blunted in AOB, indicating reduced cross-bridge cycling kinetics. Maximum Ca2+ activated force development was significantly reduced in AOB myocytes, while no change in myofilament Ca2+ sensitivity was observed. Our results indicate blunted cross-bridge cycle in a ß-MHC small animal DHF model. Reduced cross-bridge cycling kinetics may contribute, at least in part, to the development of DHF in larger mammals, including humans.

Improving Shared Situation Awareness for High-risk Therapies in Hospitalized Children.

BACKGROUND: High-risk therapies (HRTs), including medications and medical devices, are an important driver of preventable harm in children's hospitals. To facilitate shared situation awareness (SA) and thus targeted harm prevention, we aimed to increase the percentage of electronic health record (EHR) alerts with the correct descriptor of an HRT from 11% to 100% on a high-acuity hospital unit over a 6-month period. METHODS: The interdisciplinary team defined an HRT as a medication or device with a significant risk for harm that required heightened awareness. Our aim for interventions was to (1) educate staff on a new HRT algorithm; (2) develop a comprehensive table of HRTs, risks, and mitigation plans; (3) develop bedside signs for patients receiving HRTs; and (4) restructure unit huddles. Qualitative interviews with families, nurses, and medical teams were used to assess shared SA and inform the development and adaptation of interventions. The primary outcome metric was the percentage of EHR alerts for an HRT that contained a correct descriptor of the therapy for use by the care team and institutional safety leaders. RESULTS: The percentage of EHR alerts with a correct HRT descriptor increased from an average of 11% to 96%, with special cause variation noted on a statistical process control chart. Using qualitative interview data, we identified critical awareness gaps, including establishing a shared mental model between nursing staff and the medical team as well as engagement of families at the bedside to monitor for complications. CONCLUSIONS: Explicit, structured processes and huddles can increase HRT SA among the care team, patient, and family.

Enzymatic Mechanism for Arabinan Degradation and Transport in the Thermophilic Bacterium Caldanaerobius polysaccharolyticus.

The plant cell wall polysaccharide arabinan provides an important supply of arabinose, and unraveling arabinan-degrading strategies by microbes is important for understanding its use as a source of energy. Here, we explored the arabinan-degrading enzymes in the thermophilic bacterium Caldanaerobius polysaccharolyticus and identified a gene cluster encoding two glycoside hydrolase (GH) family 51 α-l-arabinofuranosidases (CpAbf51A, CpAbf51B), a GH43 endoarabinanase (CpAbn43A), a GH27 ß-l-arabinopyranosidase (CpAbp27A), and two GH127 ß-l-arabinofuranosidases (CpAbf127A, CpAbf127B). The genes were expressed as recombinant proteins, and the functions of the purified proteins were determined with para-nitrophenyl (pNP)-linked sugars and naturally occurring pectin structural elements as the substrates. The results demonstrated that CpAbn43A is an endoarabinanase while CpAbf51A and CpAbf51B are α-l-arabinofuranosidases that exhibit diverse substrate specificities, cleaving α-1,2, α-1,3, and α-1,5 linkages of purified arabinan-oligosaccharides. Furthermore, both CpAbf127A and CpAbf127B cleaved ß-arabinofuranose residues in complex arabinan side chains, thus providing evidence of the function of this family of enzymes on such polysaccharides. The optimal temperatures of the enzymes ranged between 60°C and 75°C, and CpAbf43A and CpAbf51A worked synergistically to release arabinose from branched and debranched arabinan. Furthermore, the hydrolytic activity on branched arabinan oligosaccharides and degradation of pectic substrates by the endoarabinanase and l-arabinofuranosidases suggested a microbe equipped with diverse activities to degrade complex arabinan in the environment. Based on our functional analyses of the genes in the arabinan degradation cluster and the substrate-binding studies on a component of the cognate transporter system, we propose a model for arabinan degradation and transport by C. polysaccharolyticusIMPORTANCE Genomic DNA sequencing and bioinformatic analysis allowed the identification of a gene cluster encoding several proteins predicted to function in arabinan degradation and transport in C. polysaccharolyticus The analysis of the recombinant proteins yielded detailed insights into the putative arabinan metabolism of this thermophilic bacterium. The use of various branched arabinan oligosaccharides provided a detailed understanding of the substrate specificities of the enzymes and allowed assignment of two new GH127 polypeptides as ß-l-arabinofuranosidases able to degrade pectic substrates, thus expanding our knowledge of this rare group of glycoside hydrolases. In addition, the enzymes showed synergistic effects for the degradation of arabinans at elevated temperatures. The enzymes characterized from the gene cluster are, therefore, of utility for arabinose production in both the biofuel and food industries.

Research-to-policy translation for prevention of disordered weight and shape control behaviors: A case example targeting dietary supplements sold for weight loss and muscle building.

New approaches to universal eating disorders prevention and interventions targeting macro-environmental change are greatly needed, and research-to-policy translation efforts hold promise for advancing both of these goals. This paper describes as a policy-translation case example an academic-community-government partnership of the Strategic Training Initiative for the Prevention of Eating Disorders, Multi-Service Eating Disorders Association, and the office of Massachusetts Representative Kay Khan, all based in Massachusetts, USA. The partnership's research-to-policy translation project focused on dietary supplements sold for weight loss and muscle building, which have been linked with serious injury and death in consumers. Youth and people of all ages with eating disorders and body dysmorphic disorder may be especially vulnerable to use these products due to deceptive promises of fast and safe weight loss and muscle gain. The research-to-policy translation project was informed by a triggers-to-action framework to establish the evidentiary base of harm to consumers, operationalize policy solutions to mitigate harm through legislation, and generate political will to support action through legislation introduced in the Massachusetts legislature to restrict sales of weight-loss and muscle-building dietary supplements. The paper concludes with lessons learned from this unique policy translation effort for the prevention of disordered weight and shape control behaviors and offers recommendations for next steps for the field to advance research and practice for universal, macro-environmentally targeted prevention.