Isolated Rib Fractures in Elderly Falls: Not As Deadly As We Think.

BACKGROUND: Rib fractures in elderly patients have been associated with high morbidity and mortality; however, many of these patients had substantial mechanisms of injury, which may have contributed to these high rates. OBJECTIVE: The purpose of this study was to determine the morbidity and mortality of elderly patients with isolated rib fractures who fell from standing. METHODS: A single-institution retrospective study was conducted in a Level I trauma center using the trauma registry and a separate elderly fall from standing database. Admitted patients 65 years or older who presented with rib fractures after a fall from January 2013 to June 2017 were included. Patients with a nonthoracic Abbreviated Injury Scale score greater than 2 were excluded from the study. RESULTS: Of 129 patients with isolated rib fracture, 94% (n = 121) had comorbidities and 71% (n = 92) had two or more comorbidities. Almost half (41.9%; n = 54) were taking antiplatelet and anticoagulant medications, 78.3% (n = 101) were caused by a mechanical fall, and 7% (n = 9) were caused by syncope. Data showed 72.9% (n = 94) had three or more rib fractures. The mortality rate of patients was 3.9% (n = 5). Three patients had dementia at death, four had do-not-resuscitate order, and only two deaths were directly related to pulmonary status. Patients who developed pneumonia (14.7%; n = 19) and required mechanical ventilation for a median of 11 days (3.9%; n = 5) were fewer than those in in previous studies. CONCLUSION: The morbidity and mortality associated with rib fractures are significantly less than reported in the literature when additional injuries are excluded.

The ATP-dependent chromatin remodeling enzymes CHD6, CHD7, and CHD8 exhibit distinct nucleosome binding and remodeling activities.

Proper chromatin regulation is central to genome function and maintenance. The group III chromodomain-helicase-DNA-binding (CHD) family of ATP-dependent chromatin remodeling enzymes, comprising CHD6, CHD7, CHD8, and CHD9, has well-documented roles in transcription regulation, impacting both organism development and disease etiology. These four enzymes are similar in their constituent domains, but they fill surprisingly non-redundant roles in the cell, with deficiencies in individual enzymes leading to dissimilar disease states such as CHARGE syndrome or autism spectrum disorders. The mechanisms explaining their divergent, non-overlapping functions are unclear. In this study, we performed an in-depth biochemical analysis of purified CHD6, CHD7, and CHD8 and discovered distinct differences in chromatin remodeling specificities and activities among them. We report that CHD6 and CHD7 both bind with high affinity to short linker DNA, whereas CHD8 requires longer DNA for binding. As a result, CHD8 slides nucleosomes into positions with more flanking linker DNA than CHD7. Moreover, we found that, although CHD7 and CHD8 slide nucleosomes, CHD6 disrupts nucleosomes in a distinct non-sliding manner. The different activities of these enzymes likely lead to differences in chromatin structure and, thereby, transcriptional control, at the enhancer and promoter loci where these enzymes bind. Overall, our work provides a mechanistic basis for both the non-redundant roles and the diverse mutant disease states of these enzymes in vivo.

Direct interactions promote eviction of the Sir3 heterochromatin protein by the SWI/SNF chromatin remodeling enzyme.

Heterochromatin is a specialized chromatin structure that is central to eukaryotic transcriptional regulation and genome stability. Despite its globally repressive role, heterochromatin must also be dynamic, allowing for its repair and replication. In budding yeast, heterochromatin formation requires silent information regulators (Sirs) Sir2p, Sir3p, and Sir4p, and these Sir proteins create specialized chromatin structures at telomeres and silent mating-type loci. Previously, we found that the SWI/SNF chromatin remodeling enzyme can catalyze the ATP-dependent eviction of Sir3p from recombinant nucleosomal arrays, and this activity enhances early steps of recombinational repair in vitro. Here, we show that the ATPase subunit of SWI/SNF, Swi2p/Snf2p, interacts with the heterochromatin structural protein Sir3p. Two interaction surfaces are defined, including an interaction between the ATPase domain of Swi2p and the nucleosome binding, Bromo-Adjacent-Homology domain of Sir3p. A SWI/SNF complex harboring a Swi2p subunit that lacks this Sir3p interaction surface is unable to evict Sir3p from nucleosomes, even though its ATPase and remodeling activities are intact. In addition, we find that the interaction between Swi2p and Sir3p is key for SWI/SNF to promote resistance to replication stress in vivo and for establishment of heterochromatin at telomeres.

Single-cell analysis of mast cell degranulation induced by airway smooth muscle-secreted chemokines.

BACKGROUND: Asthma is a chronic inflammatory disease characterized by narrowed airways, bronchial hyper-responsiveness, mucus hyper-secretion, and airway remodeling. Mast cell (MC) infiltration into airway smooth muscle (ASM) is a defining feature of asthma, and ASM regulates the inflammatory response by secreting chemokines, including CXCL10 and CCL5. Single cell analysis offers a unique approach to study specific cellular signaling interactions within large and complex signaling networks such as the inflammatory microenvironment in asthma. METHODS: Carbon-fiber microelectrode amperometry was used to study the effects of ASM-secreted chemokines on mouse peritoneal MC degranulation. RESULTS: MC degranulation in response to CXCL10 and CCL5 was monitored at the single cell level. Relative to IgE-mediated degranulation, CXCL10- and CCL5-stimulated MCs released a decreased amount of serotonin per granule with fewer release events per cell. Decreased serotonin release per granule was correlated with increased spike half-width and rise-time values. CONCLUSIONS: MCs are directly activated by ASM-associated chemokines. CXCL10 and CCL5 induce less robust MC degranulation compared to IgE- and A23187-stimulation. The kinetics of MC degranulation are signaling pathway-dependent, suggesting a biophysical mechanism of regulated degranulation that incorporates control over granule trafficking, transport, and docking machinery. GENERAL SIGNIFICANCE: The biophysical mechanisms, including variations in number of exocytotic release events, serotonin released per granule, and the membrane kinetics of exocytosis that underlie MC degranulation in response to CXCL10 and CCL5 were characterized at the single cell level. These findings clarify the function of ASM-derived chemokines as instigators of MC degranulation relative to classical mechanisms of MC stimulation.

Damage Control Laparotomy Wound Incisions Can Be Closed With Low Rates of Superficial Surgical Site Infections.

Due to high rates of surgical site infections (SSIs) in damage control laparotomies (DCLs), many surgeons leave wounds to heal by secondary intention. We hypothesize that patients after DCL can have their wounds primarily closed with wicks/Penrose drains with low rates of superficial surgical site infections. A retrospective review of a prospectively maintained DCL database was performed for all patients who underwent DCL from January 2016 to June 2018. From January 2016 to June 2018, a total of 171 patients underwent DCL. After exclusions, 107 patients were reviewed to assess for SSI. 57 patients were closed with wicks/Penrose drains, 3 were closed with delayed primary closure, and 47 patients were closed completely at time of fascial closure. There were 4 (3.7%) superficial SSIs, 13 (12.1%) organ space infections, and 14 surgical site occurrences (3 of which required opening the skin). Primary closure of incisions after DCL has low superficial SSI rates.

Implementation of a Stepped Care Program to Address Emotional Recovery among Traumatic Injury Patients.

BACKGROUND: Annually, over 600,000 adults served in US trauma centers (≥20%) develop posttraumatic stress disorder (PTSD) and/or depression in the first year after injury. American College of Surgeons guidelines include screening and addressing mental health recovery in trauma centers. Yet, many trauma centers do not monitor and address mental health recovery, and it is a priority to learn how to implement evidence-informed mental health programs in trauma centers. STUDY DESIGN: This report describes our application of the Exploration, Preparation, Implementation, Sustainment model to implement the Trauma Resilience and Recovery Program (TRRP) in 3 Level I and II trauma centers to address patients' mental health needs. TRRP is a scalable and sustainable stepped model of care-one of the few in the US-that provides early intervention and direct services after traumatic injury. RESULTS: Trauma centers are well positioned to accelerate patients' mental health recovery via early identification, education, screening, and referrals to mental health agencies that provide best-practice care. We found that TRRP was acceptable to the 3 partnering trauma centers we studied. Early engagement of patient, provider, and hospital administration stakeholders enhanced buy-in during the early stages of the implementation process and promoted sustainability. Active processes to support monitoring, evaluation, and adaptation were critical. CONCLUSIONS: Our work demonstrates the feasibility of implementing and adapting TRRP, a cost-efficient and sustainable stepped care intervention, in Level I and II trauma centers. Several factors should be carefully considered by trauma centers seeking to integrate behavioral health interventions into their trauma program.

Protein re-surfacing of E. coli L-Asparaginase to evade pre-existing anti-drug antibodies and hypersensitivity responses.

The optimal use of many biotherapeutics is restricted by Anti-drug antibodies (ADAs) and hypersensitivity responses which can affect potency and ability to administer a treatment. Here we demonstrate that Re-surfacing can be utilized as a generalizable approach to engineer proteins with extensive surface residue modifications in order to avoid binding by pre-existing ADAs. This technique was applied to E. coli Asparaginase (ASN) to produce functional mutants with up to 58 substitutions resulting in direct modification of 35% of surface residues. Re-surfaced ASNs exhibited significantly reduced binding to murine, rabbit and human polyclonal ADAs, with a negative correlation observed between binding and mutational distance from the native protein. Reductions in ADA binding correlated with diminished hypersensitivity responses in an in vivo mouse model. By using computational design approaches to traverse extended distances in mutational space while maintaining function, protein Re-surfacing may provide a means to generate novel or second line therapies for life-saving drugs with limited therapeutic alternatives.

Electroanalytical eavesdropping on single cell communication.

This article reviews measurement of single cell exocytosis with microelectrodes, covering history, basic instrumentation, cell types investigated, and fundamental insight gained.

Development of Trauma Level Prediction Models Using Emergency Medical Service Vital Signs to Reduce Over- and Undertriage Rates in Penetrating Wounds and Falls of the Elderly.

Determining triage activation levels in geriatric patients who fall (GF), and patients with penetrating wounds can be difficult and inaccurate, resulting in excessive overtriage (OT) and undertriage (UT) rates. We developed trauma activation prediction models using field data to predict with greater accuracy trauma activation level and triage rates consistent with the ACS recommendations. Using data from the 2014 National Trauma Data Bank, we created binary regression equations for each type of injury (GF and penetrating wounds). The 2014 data were randomized and divided into two halves. The first half for each injury type was used to generate prediction models, whereas the second half of the 2014 data were combined with 2013 and 2015 National Trauma Data Bank data for model verification. Binary regression equations were generated from vital signs collected by EMS. A Cribari grid with ISS ≥ 15 was used to determine the appropriateness of activation level. Chi-square analysis was used to determine significant differences between OT, UT, and accuracy predictions. Using our triage models, we were able to obtain UT rates of less than 4 per cent for GF with OT rates of less than 40 per cent, UT rates less than 4.1 per cent and OT of less than 50 per cent for patients with gunshot wounds, and UT rates less than 4 per cent and OT rates less than 25 per cent for patients who had stab wounds. Our developed trauma level prediction models enable health providers to predict trauma activation levels that can result in OT and UT rates in the recommended ranges by the ACS.

Trauma Patients' Attitudes toward Organ Donation at an Urban Level I Trauma Center.

Many health-care workers (HCWs) surveyed at a trauma center believed their patients distrusted the organ allocation system. This study compares urban trauma patients' (TPs) attitudes toward organ donation with attitudes from the 2012 National Survey of Organ Donation Attitudes (NSODA). TPs presenting to the trauma clinic between September 2014 and August 2015 were surveyed. Patient responses were compared with the 2012 NSODA. One hundred and thirty-three TPs (95.0%) responded to the survey. Compared with the 2012 NSODA, groups were similar with regard to a patient's desire for OD after death (Trauma: 62.4% [Confidence interval [CI]: 53.6-70.7] vs NSODA: 59.3% [CI: 56.6-61.8]) and the belief that doctors are less likely to save their life if they are an organ donor (24.8% [CI: 17.7-33.0] vs 19.6% [CI: 18.3-21.0]). Approximately, 30 per cent of patients believed discrimination prevented minority patients from receiving transplants (27.1 [CI: 19.7-35.5] vs 30.3 [CI: 28.8-31.9]). TPs were less likely than the NSODA group to donate a family members' organs, if they did not know the family members' wishes (56.4% [CI: 47.5-65.0] vs 75.6% [CI: 68.7-71.8]); TPs were less likely to believe the United States transplant system uses a fair approach to distribute organs (47.4% [38.7-56.2] vs 64.6% [CI: 63.0-66.2]). Adjusting for race, both groups were similar in their willingness to donate a family members' organs; black TPs were less likely to believe the United States transplant system, which follows a fair approach in distributing organs (43.0% [CI: 32.4-54.2] vs 63.7% [59.7-67.6]). Despite HCWs perceptions, TPs had a positive view of OD. Educating HCWs on patient attitudes toward OD may decrease institutional barriers to OD.

Outcomes of Endoscopic Stenting for Traumatic Biliary and Pancreatic Fistulae.

The role of endoscopic retrograde cholangiopancreatography (ERCP) in the trauma patient is limited. Therefore, reporting of outcomes is sparse in the literature. The purpose of this study was to review outcomes of patients who underwent ERCP for traumatic biliopancreatic injury. We retrospectively reviewed 1550 ERCPs, from a prospectively maintained database, performed by a single surgical endoscopist consulted by the trauma surgical service for the management of traumatic fistulae. Referral was made for patients with high output (greater than 200 mL/d) and/or persistent (failure to resolve within 30 days) fistulae and traumatic biliary stricture. Primary end point was postprocedural complications. Secondary end points included patient characteristics, stents placed, and duration of stenting. Seventeen patients underwent a total of 31 ERCPs for biliary and/or pancreatic injury resulting from abdominal trauma (eight penetrating, nine blunt). Fourteen patients had ERCP after laparotomy, with a mean interval to ERCP of 74 days. In three patients, ERCP was the only intervention required. Fourteen biliary stents were placed, seven of which were metallic. Ten pancreatic stents were placed; one proximally migrated but was successfully retrieved. Four patients had both ducts simultaneously stented. The mean duration of stenting was 158 days. All fistulae resolved after stenting. There were no serious complications.

Neuropeptide-Induced Mast Cell Degranulation and Characterization of Signaling Modulation in Response to IgE Conditioning.

As tissue-resident immune cells, mast cells are frequently found in close proximity to afferent neurons and are subjected to immunoactive mediators secreted by these neurons, including substance P (SP) and calcitonin gene-related peptide (CGRP). Neurogenic inflammation is thought to play an important role in the pathophysiology of many diseases. Unraveling the cellular mechanisms at the interface between the immune response and the peripheral nervous system is important for understanding how these diseases arise and progress. In this work, mast cell degranulation following direct exposure to CGRP and SP was studied both at the bulk and single-cell levels to characterize the mouse peritoneal mast cell response to neuropeptides and compare this response to well-studied mast cell activation pathways. Results show that mast cells secrete fewer chemical messenger-filled granules with increased IgE preincubation concentrations. The biophysical characteristics of mast cell degranulation in response to SP and CGRP is in many ways similar to calcium ionophore-induced mast cell degranulation; however, neuropeptide-stimulated mast cells secrete reduced chemical messenger content per secretion event, resulting in an overall relative decrease in secreted chemical messengers.

Selective management of blunt hepatic injuries including nonoperative management is a safe and effective strategy.

BACKGROUND: The justification and preference for operative versus nonoperative management of hepatic injuries caused by blunt trauma remains ambiguous. This review assesses the outcome of operative and nonoperative management of liver injury after blunt trauma. METHODS: We retrospectively reviewed the demographics, severity of injury, severity of liver injury, associated concomitant injuries, management scheme, and outcome of patients with documented hepatic injury from 1993 to 2003. RESULTS: The overall mortality rate was 9.4%, with 3.7% caused by the liver injury itself. Fifty-nine percent (330 of 561) of liver injuries were of low severity (grades I and II), with an overall mortality rate of 6.6% caused by concomitant injuries and liver-related mortality of 0%. Forty-one percent (231 of 561) of liver injuries were high-severity injuries (grades III, IV, and V). Mortality for nonoperative management of high-severity liver injuries was 2.2%. If operative intervention was required because of hemodynamic instability or concomitant injuries then the mortality rate was significantly higher at 30%. Forty-two of the 378 (11%) liver injuries treated nonoperatively required an adjunctive procedure for successful management. CONCLUSIONS: Selective management of liver injuries presented a low liver-related mortality rate. Low-grade injuries can be managed nonoperatively with excellent results. High-grade injuries can be managed nonoperatively, if operative intervention is not required for hemodynamic instability or associated injuries, with a low mortality. In these patients, adjunctive procedures will be required selectively for successful nonoperative management of high-grade liver injuries. High-grade injuries requiring operative management because of hemodynamic instability or concomitant injuries continue to have significantly higher mortality.

Building clinical networks: a developmental evaluation framework.

BACKGROUND: Clinical networks have been designed as a cross-organisational mechanism to plan and deliver health services. With recent concerns about the effectiveness of these structures, it is timely to consider an evidence-informed approach for how they can be developed and evaluated. OBJECTIVE: To document an evaluation framework for clinical networks by drawing on the network evaluation literature and a 5-year study of clinical networks. METHOD: We searched literature in three domains: network evaluation, factors that aid or inhibit network development, and on robust methods to measure network characteristics. This material was used to build a framework required for effective developmental evaluation. RESULTS: The framework's architecture identifies three stages of clinical network development; partner selection, network design and network management. Within each stage is evidence about factors that act as facilitators and barriers to network growth. These factors can be used to measure progress via appropriate methods and tools. The framework can provide for network growth and support informed decisions about progress. CONCLUSIONS: For the first time in one place a framework incorporating rigorous methods and tools can identify factors known to affect the development of clinical networks. The target user group is internal stakeholders who need to conduct developmental evaluation to inform key decisions along their network's developmental pathway.

Solution-state conformation and stoichiometry of yeast Sir3 heterochromatin fibres.

Heterochromatin is a repressive chromatin compartment essential for maintaining genomic integrity. A hallmark of heterochromatin is the presence of specialized nonhistone proteins that alter chromatin structure to inhibit transcription and recombination. It is generally assumed that heterochromatin is highly condensed. However, surprisingly little is known about the structure of heterochromatin or its dynamics in solution. In budding yeast, formation of heterochromatin at telomeres and the homothallic silent mating type loci require the Sir3 protein. Here, we use a combination of sedimentation velocity, atomic force microscopy and nucleosomal array capture to characterize the stoichiometry and conformation of Sir3 nucleosomal arrays. The results indicate that Sir3 interacts with nucleosomal arrays with a stoichiometry of two Sir3 monomers per nucleosome. We also find that Sir3 fibres are less compact than canonical magnesium-induced 30 nm fibres. We suggest that heterochromatin proteins promote silencing by 'coating' nucleosomal arrays, stabilizing interactions between nucleosomal histones and DNA.

Time- and concentration-dependent effects of exogenous serotonin and inflammatory cytokines on mast cell function.

Mast cells play a significant role in both the innate and adaptive immune response; however, the tissue-bound nature of mast cells presents an experimental roadblock to performing physiologically relevant mast cell experiments. In this work, a heterogeneous cell culture containing primary culture murine peritoneal mast cells (MPMCs) was studied to characterize the time-dependence of mast cell response to allergen stimulation and the time- and concentration-dependence of the ability of the heterogeneous MPMC culture to uptake and degranulate exogenous serotonin using high performance liquid chromatography (HPLC) coupled to an electrochemical detector. Additionally, because mast cells play a central role in asthma, MPMCs were exposed to CXCL10 and CCL5, two important asthma-related inflammatory cytokines that have recently been shown to induce mast cell degranulation. MPMC response to both allergen exposure and cytokine exposure was evaluated for 5-HT secretion and bioactive lipid formation using ultraperformance liquid chromatography coupled to an electrospray ionization triple quadrupole mass spectrometer (UPLC-MS/MS). In this work, MPMC response was shown to be highly regulated and responsive to subtle alterations in a complex environment through time- and concentration-dependent degranulation and bioactive lipid formation. These results highlight the importance of selecting an appropriate mast cell model when studying mast cell involvement in allergic response and inflammation.

Releasing the brakes on a chromatin-remodeling enzyme.

Chromatin-remodeling enzymes use the energy from ATP hydrolysis to mobilize, disrupt or change the histone composition of nucleosomes, facilitating nearly every nuclear event. Two recent studies indicate that remodeling enzymes harness the power of an ancient constitutively active DNA translocase and that different remodeling enzymes may use specialized coupling domains that communicate the presence of nucleosomal epitopes to regulate translocase and remodeling activity.

Higher-order unfolding of satellite heterochromatin is a consistent and early event in cell senescence.

Epigenetic changes to chromatin are thought to be essential to cell senescence, which is key to tumorigenesis and aging. Although many studies focus on heterochromatin gain, this work demonstrates large-scale unraveling of peri/centromeric satellites, which occurs in all models of human and mouse senescence examined. This was not seen in cancer cells, except in a benign senescent tumor in vivo. Senescence-associated distension of satellites (SADS) occurs earlier and more consistently than heterochromatin foci formation, and SADS is not exclusive to either the p16 or p21 pathways. Because Hutchinson Guilford progeria syndrome patient cells do not form excess heterochromatin, the question remained whether or not proliferative arrest in this aging syndrome involved distinct epigenetic mechanisms. Here, we show that SADS provides a unifying event in both progeria and normal senescence. Additionally, SADS represents a novel, cytological-scale unfolding of chromatin, which is not concomitant with change to several canonical histone marks nor a result of DNA hypomethylation. Rather, SADS is likely mediated by changes to higher-order nuclear structural proteins, such as LaminB1.