Clinical outcomes of a prospective randomized comparison of bioreactance monitoring versus pulse-contour analysis in a stroke-volume based goal-directed fluid resuscitation protocol in brain-dead organ donors.

Eighty percent of brain-dead (BD) organ donors develop hypotension and are frequently hypovolemic. Fluid resuscitation in a BD donor is controversial. We have previously published our 4-h goal-directed stroke volume (SV)-based fluid resuscitation protocol which significantly decreased time on vasopressors and increased transplanting four or more organs. The SV was measured by pulse-contour analysis (PCA) or an esophageal doppler monitor, both of which are invasive. Thoracic bioreactance (BR) is a non-invasive portable technology that measures SV but has not been studied in BD donors. We performed a randomized prospective comparative study of BR versus PCA technology in our fluid resuscitation protocol in BD donors. Eighty-four donors (53.1%) were randomized to BR and 74 donors to PCA (46.8%). The two groups were well matched based on 24 demographic, social, and initial laboratory factors, without any significant differences between them. There was no difference in the intravenous fluid infused over the 4-h study period [BR 2271 ± 823 vs. PCA 2230 ± 962 mL; p = .77]. There was no difference in the time to wean off vasopressors [BR 108.8 ± 61.8 vs. PCA 150.0 ± 68 min p = .07], nor in the number of donors off vasopressors at the end of the protocol [BR 16 (28.6%) vs. PCA 15 (29.4%); p = .92]. There was no difference in the total number of organs transplanted per donor [BR 3.25 ± 1.77 vs. PCA 3.22 ± 1.75; p = .90], nor in any individual organ transplanted. BR was equivalent to PCA in clinical outcomes and provides a simple, non-invasive, portable technology to monitor fluid resuscitation in organ donors.

A stroke volume-based fluid resuscitation protocol decreases vasopressor support and may increase organ yield in brain-dead donors.

Brain-dead donors are frequently hypovolemic and hypotensive requiring vasopressor support. We studied a stroke volume-based fluid resuscitation and vasopressor weaning protocol prospectively on 64 hypotensive donors, with a recent control cohort of 30 hypotensive donors treated without a protocol. Stroke volume was measured every 30 minutes for 4 hours by pulse contour analysis or esophageal Doppler. A 500 mL saline fluid bolus was infused over 30 minutes and repeated if the stroke volume increased by 10%. No fluid was infused if the stroke volume did not increase by 10%. Vasopressors were weaned every 10 minutes if the mean arterial pressure was greater than 65 mm Hg. The protocol group received 1937 ± 906 mL fluid compared to 1323 ± 919 mL in the control group (P = .003). Mean time on vasopressors was decreased from 957.6 ± 586.2 to 176.3 ± 82.2 minutes (P<.001). Donors in the protocol group were more likely to donate four or more organs than donors in the control group (OR = 4.114, 95% Confidence Interval (CI) = 1.003-16.876). While more organs were transplanted per donor in the protocol group (3.39 ± 1.52) than in the control group (2.93 ± 1.44) (P = .268), the difference did not reach statistical significance. A goal-directed fluid resuscitation protocol decreased organ ischemia and may increase organs transplanted.

Impact of shoulder internal rotation on ulnar nerve excursion and strain in embalmed cadavers. A pilot study.

DESIGN: Laboratory study, repeated-measures design. OBJECTIVE: To determine if the substitution of shoulder internal rotation for external rotation during the upper limb neurodynamic test (ULNT3) evokes a comparable ulnar nerve excursion and strain in embalmed cadavers. Shoulder external rotation is a primary movement component of the ULNT3. It has been suggested that shoulder internal rotation may provide a similar load to the nervous system. There are no data to either support or negate this claim. METHODS: Excursion and strain were measured in the ulnar nerve of six embalmed cadavers during the traditional ULNT3 and an experimental maneuver using shoulder internal rotation. RESULTS: The total means±SD of excursion for the traditional and experimental maneuvers were 2·11±0·89 and 2·09±0·92 mm, respectively. The total means±SD of strain for the traditional and experimental maneuvers were 5·274±2·223 and 5·241±2·308%, respectively. A very strong correlation (r = 0·98) was shown to exist between maneuvers and this relationship was determined to be significant (P = 0·001). DISCUSSION: The results of this study provide evidence that there is no appreciable difference in excursion or strain when substituting shoulder internal rotation for external rotation during the ULNT3. Patients who exhibit limitation of shoulder external rotation mobility may benefit from this substitution when presenting with signs of ulnar nerve pathodynamics. Further research involving patients will be needed to assess the validity of the experimental maneuver for clinical application.

Ultrafast growth of wadsleyite in shock-produced melts and its implications for early solar system impact processes.

We observed micrometer-sized grains of wadsleyite, a high-pressure phase of (Mg,Fe)(2)SiO(4,) in the recovery products of a shock experiment. We infer these grains crystallized from shock-generated melt over a time interval of <1 micros, the maximum time over which our experiment reached and sustained pressure sufficient to stabilize this phase. This rapid crystal growth rate (approximately 1 m/s) suggests that, contrary to the conclusions of previous studies of the occurrence of high-pressure phases in shock-melt veins in strongly shocked meteorites, the growth of high-pressure phases from the melt during shock events is not diffusion-controlled. Another process, such as microturbulent transport, must be active in the crystal growth process. This result implies that the times necessary to crystallize the high-pressure phases in shocked meteorites may correspond to shock pressure durations achieved on impacts between objects 1-5 m in diameter and not, as previously inferred, approximately 1-5 km in diameter. These results may also provide another pathway for syntheses, via shock recovery, of some high-value, high-pressure phases.

A comparative study of fragment screening methods on the p38α kinase: new methods, new insights.

The stress-activated kinase p38α was used to evaluate a fragment-based drug discovery approach using the BioFocus fragment library. Compounds were screened by surface plasmon resonance (SPR) on a Biacore(™) T100 against p38α and two selectivity targets. A sub-set of our library was the focus of detailed follow-up analyses that included hit confirmation, affinity determination on 24 confirmed, selective hits and competition assays of these hits with respect to a known ATP binding site inhibitor. In addition, functional activity against p38α was assessed in a biochemical assay using a mobility shift platform (LC3000, Caliper LifeSciences). A selection of fragments was also evaluated using fluorescence lifetime (FLEXYTE(™)) and microscale thermophoresis (Nanotemper) technologies. A good correlation between the data for the different assays was found. Crystal structures were solved for four of the small molecules complexed to p38α. Interestingly, as determined both by X-ray analysis and SPR competition experiments, three of the complexes involved the fragment at the ATP binding site, while the fourth compound bound in a distal site that may offer potential as a novel drug target site. A first round of optimization around the remotely bound fragment has led to the identification of a series of triazole-containing compounds. This approach could form the basis for developing novel and active p38α inhibitors. More broadly, it illustrates the power of combining a range of biophysical and biochemical techniques to the discovery of fragments that facilitate the development of novel modulators of kinase and other drug targets.

Sepsis.

This article provides an overview of the history of the sepsis definitions as well as an overview of the current understanding of the pathogenesis of sepsis. The evolution of the treatment bundles is also presented.

Survey of Nurses' Experiences Applying The Joint Commission's Medication Management Titration Standards.

BACKGROUND: Critical care nurses titrate continuous infusions of medications to achieve clinical end points. In 2017, The Joint Commission (TJC) placed restrictions on titration practice, decreasing nurses' autonomous decision-making. OBJECTIVES: To describe the practice and perceptions of nurses regarding the 2017 TJC accreditation/regulatory standards for titration of continuous medication infusions. METHODS: A survey of nurses' experiences titrating continuous medication infusions was developed, validated, and distributed electronically to members of the American Association of Critical-Care Nurses. RESULTS: The content validity index for the survey was 1.0 for relevance and 0.95 for clarity. A total of 781 nurses completed the survey; 625 (80%) perceived titration standards to cause delays in patient care, and 726 (93%) experienced moral distress (mean [SD], 4.97 [2.67]; scale, 0-10). Among respondents, 33% could not comply with titration orders, 68% reported suboptimal care resulting from pressure to comply with orders, 70% deviated from orders to meet patient needs, and 84% requested revised orders to ensure compliance. Suboptimal care and delays in care significantly and strongly (regression coefficients ≥0.69) predicted moral distress. CONCLUSIONS: Critical care nurses perceive TJC medication titration standards to adversely impact patient care and contribute to moral distress. The improved 2020 updates to the standards do not address delays and inability to comply with orders, leading to moral distress. Advocacy is indicated in order to mitigate unintended consequences of TJC medication management titration standards.

Oligosaccharides of Hyaluronan activate dendritic cells via toll-like receptor 4.

Low molecular weight fragmentation products of the polysaccharide of Hyaluronic acid (sHA) produced during inflammation have been shown to be potent activators of immunocompetent cells such as dendritic cells (DCs) and macrophages. Here we report that sHA induces maturation of DCs via the Toll-like receptor (TLR)-4, a receptor complex associated with innate immunity and host defense against bacterial infection. Bone marrow-derived DCs from C3H/HeJ and C57BL/10ScCr mice carrying mutant TLR-4 alleles were nonresponsive to sHA-induced phenotypic and functional maturation. Conversely, DCs from TLR-2-deficient mice were still susceptible to sHA. In accordance, addition of an anti-TLR-4 mAb to human monocyte-derived DCs blocked sHA-induced tumor necrosis factor alpha production. Western blot analysis revealed that sHA treatment resulted in distinct phosphorylation of p38/p42/44 MAP-kinases and nuclear translocation of nuclear factor (NF)-kappa B, all components of the TLR-4 signaling pathway. Blockade of this pathway by specific inhibitors completely abrogated the sHA-induced DC maturation. Finally, intravenous injection of sHA-induced DC emigration from the skin and their phenotypic and functional maturation in the spleen, again depending on the expression of TLR-4. In conclusion, this is the first report that polysaccharide degradation products of the extracellular matrix produced during inflammation might serve as an endogenous ligand for the TLR-4 complex on DCs.

Narrative History of the Swan-Ganz Catheter: Development, Education, Controversies, and Clinician Acumen.

The year 2020 marks the 50th anniversary of the landmark publication on the bedside clinical use of a flow-directed catheter. The catheter, now known as the Swan-Ganz catheter, truly revolutionized practice and care of the critically ill. Use of the catheter proliferated nearly without rigorous validation or evidence base until a moratorium was called in regard to its use. This article describes the history of the development of the Swan-Ganz catheter, its uses, and its near downfall. The authors, both involved in educating clinicians in the use of the pulmonary artery catheter, hope that telling this story shares tribal knowledge and lessons learned with newer generations of nurses who did not experience the explosion of development and knowledge in the area of hemodynamic monitoring. Partly because of advances in technology, and the catheter's application for heart failure in particular, use of the pulmonary catheter is being resurrected.

Challenges in Sepsis Care: New Sepsis Definitions and Fluid Resuscitation Beyond the Central Venous Pressure.

There are two important recent changes in sepsis care. The first key change is the 2016 Sepsis-3 definitions from the recent consensus workgroup with new sepsis and septic shock definitions. Useful tools for assessing patients that have a greater risk of mortality include Sequential Organ Failure Assessment (SOFA) in intensive care units and quick SOFA outside intensive care units. The second change involves management of fluid resuscitation and measures of volume responsiveness. Measures such as blood pressure and central venous pressure are not reliable. Fluid challenges and responsiveness should be based on stroke volume change of greater than 10%.

Homoassociation of VE-cadherin follows a mechanism common to "classical" cadherins.

Vascular endothelial cadherin (VE-cadherin/cadherin5) is specifically expressed in adherens junctions of endothelial cells and exerts important functions in cell-cell adhesion as well as signal transduction. To analyze the mechanism of VE-cadherin homoassociation, the ectodomains CAD1-5 were connected by linker sequences to the N terminus of the coiled-coil domain of cartilage matrix protein (CMP). The chimera VECADCMP were expressed in mammalian cells. The trimeric coiled-coil domain leads to high intrinsic domain concentrations and multivalency promoting self-association. Ca(2+)-dependent homophilic association of VECADCMP was detected in solid phase assays and cross-linking experiments. A striking analogy to homoassociation of type I ("classical") cadherins like E, N or P-cadherin was observed when interactions in VECADCMP and between these trimeric proteins were analyzed by electron microscopy. Ca(2+)-dependent ring-like and double ring-like arrangements suggest interactions between domains 1 and 2 of the ectodomains, which may be correlated with lateral and adhesive contacts in the adhesion process. Association to complexes composed of two VECADCMP molecules was also demonstrated by chemical cross-linking. No indication for an antiparallel association of VECAD ectodomains to hexameric complexes as proposed by Legrand et al. was found. Instead the data suggest that homoassociation of VE-cadherin follows the conserved mechanism of type I cadherins.

Calcium-dependent homoassociation of E-cadherin by NMR spectroscopy: changes in mobility, conformation and mapping of contact regions.

Cadherins are calcium-dependent cell surface proteins that mediate homophilic cellular adhesion. The calcium-induced oligomerization of the N-terminal two domains of epithelial cadherin (ECAD12) was followed by NMR spectroscopy in solution over a large range of protein (10 microM-5 mM) and calcium (0-5 mM) concentrations. Several spectrally distinct states could be distinguished that correspond to a calcium-free monomeric form, a calcium-bound monomeric form, and to calcium-bound higher oligomeric forms. Chemical shift changes between these different states define calcium-binding residues as well as oligomerization contacts. Information about the relative orientation and mobility of the ECAD12 domains in the various states was obtained from weak alignment and 15N relaxation experiments. The data indicate that the calcium-free ECAD12 monomer adopts a flexible, kinked conformation that occludes the dimer interface observed in the ECAD12 crystal structure. In contrast, the calcium-bound monomer is already in a straight, non-flexible conformation where this interface is accessible. This mechanism provides a rational for the calcium-induced adhesiveness. Oligomerization induces chemical shift changes in an area of domain CAD1 that is centered at residue Trp-2. These shift changes extend to almost the entire surface of domain CAD1 at high (5 mM) protein concentrations. Smaller additional clusters of shift perturbations are observed around residue A80 in CAD1 and K160 in CAD2. According to weak alignment and relaxation data, the symmetry of a predominantly dimeric solution aggregate at 0.6 mM ECAD12 differs from the approximate C2-symmetry of the crystalline dimer.

Stroke volume optimization: the new hemodynamic algorithm.

Critical care practices have evolved to rely more on physical assessments for monitoring cardiac output and evaluating fluid volume status because these assessments are less invasive and more convenient to use than is a pulmonary artery catheter. Despite this trend, level of consciousness, central venous pressure, urine output, heart rate, and blood pressure remain assessments that are slow to be changed, potentially misleading, and often manifested as late indications of decreased cardiac output. The hemodynamic optimization strategy called stroke volume optimization might provide a proactive guide for clinicians to optimize a patient's status before late indications of a worsening condition occur. The evidence supporting use of the stroke volume optimization algorithm to treat hypovolemia is increasing. Many of the cardiac output monitor technologies today measure stroke volume, as well as the parameters that comprise stroke volume: preload, afterload, and contractility.

Effect of kinetic therapy on pulmonary complications.

BACKGROUND: Optimal turning of critically ill patients is not well established. Kinetic therapy (systematic mechanical rotation of patients with 40 degree turns) may improve pulmonary function more than the improvement in function achieved via the standard of care (turning patients every 2 hours). OBJECTIVE: To determine (1) if patients receiving mechanical ventilation who tolerate kinetic therapy have better pulmonary function than do patients treated with standard turning and (2) the cost-effectiveness of kinetic therapy. METHODS: A prospective, randomized, multicenter study including 234 medical, surgical, and trauma patients (137 control patients, 97 patients receiving kinetic therapy). RESULTS: Kinetic therapy significantly decreased the occurrence of ventilator-associated pneumonia and lobar atelectasis. The risk of pneumonia developing was lower (P = .002) in patients receiving kinetic therapy than in the control patients. The risk of lobar atelectasis developing was decreased (P = .02) for the patients receiving kinetic therapy. Lengths of stay in the intensive care unit and in the hospital did not differ between the groups. Charges for intensive care were less in the kinetic therapy group (81,700 dollars) than in the control group (84,958 dollars), but not significantly less. Twenty-one patients did not tolerate kinetic therapy and were not included in the analysis. CONCLUSION: Kinetic therapy helps prevent ventilator-associated pneumonia and lobar atelectasis in critically ill patients. Costs to rent the bed may be offset by the potential cost reduction associated with kinetic therapy.

Efficient hit-finding approaches for histone methyltransferases: the key parameters.

For many novel epigenetics targets the chemical ligand space and structural information were limited until recently and are still largely unknown for some targets. Hit-finding campaigns are therefore dependent on large and chemically diverse libraries. In the specific case of the histone methyltransferase G9a, the authors have been able to apply an efficient process of intelligent selection of compounds for primary screening, rather than screening the full diverse deck of 900 000 compounds to identify hit compounds. A number of different virtual screening methods have been applied for the compound selection, and the results have been analyzed in the context of their individual success rates. For the primary screening of 2112 compounds, a FlashPlate assay format and full-length histone H3.1 substrate were employed. Validation of hit compounds was performed using the orthogonal fluorescence lifetime technology. Rated by purity and IC(50) value, 18 compounds (0.9% of compound screening deck) were finally considered validated primary G9a hits. The hit-finding approach has led to novel chemotypes being identified, which can facilitate hit-to-lead projects. This study demonstrates the power of virtual screening technologies for novel, therapeutically relevant epigenetics protein targets.

Time-of-flight mass spectrometry of mineral volatilization: toward direct composition analysis of shocked mineral vapor.

We have developed an orthogonal-acceleration time-of-flight mass spectrometer to study the volatiles produced when a mineral's shock-compressed state is isentropically released, as occurs when a shock wave, driven into the mineral by an impact, reflects upon reaching a free surface. The instrument is designed to use a gun or explosive-launched projectile as the source of the shock wave, impact onto a flange separating a poor vacuum and the high vacuum (10(-7) Torr) interior of the mass spectrometer, and transmission of the shock wave through the flange to a mineral sample mounted on the high-vacuum side of the flange. The device extracts and analyzes the neutrals and ions produced from the shocked mineral prior to the possible occurrence of collateral instrument damage from the shock-inducing impact. The instrument has been tested using laser ablation of various mineral surfaces, and the resulting spectra are presented. Mass spectra are compared with theoretical distributions of molecular species, and with expected distributions from laser desorption.

Insights into the low adhesive capacity of human T-cadherin from the NMR structure of Its N-terminal extracellular domain.

T-cadherin is unique among the family of type I cadherins, because it lacks transmembrane and cytosolic domains, and attaches to the membrane via a glycophosphoinositol anchor. The N-terminal cadherin repeat of T-cadherin (Tcad1) is approximately 30% identical to E-, N-, and other classical cadherins. However, it lacks many amino acids crucial for their adhesive function of classical cadherins. Among others, Trp-2, which is the key residue forming the canonical strand-exchange dimer, is replaced by an isoleucine. Here, we report the NMR structure of the first cadherin repeat of T-cadherin (Tcad1). Tcad1, as other cadherin domains, adopts a beta-barrel structure with a Greek key folding topology. However, Tcad1 is monomeric in the absence and presence of calcium. Accordingly, lle-2 binds into a hydrophobic pocket on the same protomer and participates in an N-terminal beta-sheet. Specific amino acid replacements compared to classical cadherins reduce the size of the binding pocket for residue 2 and alter the backbone conformation and flexibility around residues 5 and 15 as well as many electrostatic interactions. These modifications apparently stabilize the monomeric form and make it less susceptible to a conformational switch upon calcium binding. The absence of a tendency for homoassociation observed by NMR is consistent with electron microscopy and solid-phase binding data of the full T-cadherin ectodomain (Tcad1-5). The apparent low adhesiveness of T-cadherin suggests that it is likely to be involved in reversible and dynamic cellular adhesion-deadhesion processes, which are consistent with its role in cell growth and migration.