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.

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.

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.

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.

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.

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%.

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.

Efficient Hit-Finding Approaches for Histone Methyltransferases

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 IC50 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.

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.

Effect of the green tea polyphenol epigallocatechin gallate (EGCG) on growth and IL-6 signalling pathways in malignant plasma cells

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Background: Epigallocatechin gallate (EGCG) is the predominant polyphenolic constituent of green tea leaves that possesses antitumor, antiinflammatory, and antioxidant activity. EGCG exerts its effects through potentially multiple mechanisms including inhibition of growth factor receptor signalling. The compound is currently under investigation in a phase I/II clinical trial for treatment of patients with early stage chronic lymphocytic leukemia at Mayo Clinic. The goal of our study was to examine the in vitro effects of EGCG in multiple myeloma (MM). Methods: A panel of human myeloma cell lines (n=6) including the IL-6 dependent INA-6 cell line was used to evaluate the sensitivity to EGCG. Cells were cultured for three days in the absence or presence of EGCG at concentrations between 6.25 μM and 100 μM. Cell viability was determined in a colorimetric tetrazolium (MTS) based assay and by trypanblue exclusion. For signalling experiments, INA-6 cells were IL-6 and serum starved and then treated with EGCG for two hours before IL-6 was added. Whole cell lysates were prepared and subjected to SDS-PAGE and Western blot analysis. Results: EGCG inhibited the in vitro growth of human myeloma cell lines by inducing cell death in a time and dose-dependent manner. IC50 concentrations were between 12,5 μM and 50 μM. IL-6 mediated growth of INA-6 cells was inhibited at similar doses. The addition of excess amounts of IL-6 could not protect from EGCG induced cytotoxicity. Pretreatment of INA-6 cells with EGCG resulted in a dose-dependent inhibition of IL-6 induced STAT3 tyrosine phosphorylation. In these cells, stimulation with IL-6 leads to upregulation of Mcl-1 expression. In contrast, phosphorylation of p44/p42 MAPK, which is constitutively activated in INA-6 cells, was not affected. Conclusion: EGCG has growth inhibitory activity on myeloma cells. Specific inhibition of signalling pathways that regulate expression of anti-apoptotic proteins could be one mechanism how EGCG exerts its activity. Our work provides the rationale for further studies to evaluate the effect of EGCG not only in B-CLL, but also in plasma cell tumors.

No significant financial relationships to disclose.

Osteopontin functionally activates dendritic cells and induces their differentiation toward a Th1-polarizing phenotype

Osteopontin (OPN) has been shown to have T helper 1 (Th1) cytokine functions in cell-mediated immunity. Deficiency of OPN is linked to a reduced Th1 immune response in autoimmunity, infectious disease, and delayed-type allergy. Dendritic cells (DCs) are central for the induction of T-cell-mediated immunity, when initially flexible DCs are instructed by priming signals and tissue-derived factors to adopt Th1, Th2, or regulatory T-cell-inducing phenotypes. Although OPN influences the cytokine secretion of T cells and macrophages, its effects on DC polarization remain an important missing link in the understanding of OPN functions in Th1 immunity. Here we demonstrate that OPN promotes the emigration of human DCs from the epidermis and functionally activates myeloid-type DCs, augmenting their expression of HLA-DR, costimulatory, and adhesion molecules. OPN induces their Th1-promoting tumor necrosis factor alpha (TNF-alpha) and interleukin-12 (IL-12) secretion, and enhances their allostimulatory capacity. In mixed lymphocyte reactions (MLRs), OPN stimulates IL-12 secretion by DCs, inducing elevated interferon-gamma (IFN-gamma) production by T cells. Naive Th cells stimulated by OPN-activated DCs show a Th1-polarized cytokine production. Our findings identify OPN as an important tissue-derived factor that DCs encounter when traveling from peripheral sites of activation to secondary lymphatic organs, which induces DC maturation toward a Th1-promoting phenotype.

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° 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) than in the control group ($84 958), 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.

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.

Proteolytic E-cadherin activation followed by solution NMR and X-ray crystallography

Cellular adhesion by classical cadherins depends critically on the exact proteolytic removal of their N-terminal prosequences. In this combined solution NMR and X-ray crystallographic study, the consequences of propeptide cleavage of an epithelial cadherin construct (domains 1 and 2) were followed at atomic level. At low protein concentration, the N-terminal processing induces docking of the tryptophan-2 side-chain into a binding pocket on the same molecule. At high concentration, cleavage induces dimerization (KD=0.72 mM, k(off)=0.7 s(-1)) and concomitant intermolecular exchange of the betaA-strands and the tryptophan-2 side-chains. Thus, the cleavage represents the switch from a nonadhesive to the functional form of cadherin.

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.

Soil warming and carbon-cycle feedbacks to the climate system

In a decade-long soil warming experiment in a mid-latitude hardwood forest, we documented changes in soil carbon and nitrogen cycling in order to investigate the consequences of these changes for the climate system. Here we show that whereas soil warming accelerates soil organic matter decay and carbon dioxide fluxes to the atmosphere, this response is small and short-lived for a mid-latitude forest, because of the limited size of the labile soil carbon pool. We also show that warming increases the availability of mineral nitrogen to plants. Because plant growth in many mid-latitude forests is nitrogen-limited, warming has the potential to indirectly stimulate enough carbon storage in plants to at least compensate for the carbon losses from soils. Our results challenge assumptions made in some climate models that lead to projections of large long-term releases of soil carbon in response to warming of forest ecosystems.

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.

Analysis of heterophilic and homophilic interactions of cadherins using the c-Jun/c-Fos dimerization domains

Cadherin-mediated cell-cell adhesion is initiated by cis dimerization of cadherin ectodomains at the cell surface followed by an antiparallel trans interaction of dimers on opposing cells. To resolve open questions concerning the molecular details and specificity of cis and trans interactions, ectodomains of E- and P-cadherin were analyzed by chemical cross-linking and by electron microscopy. At the high intrinsic concentration created by artificial oligomerization the N-terminal cadherin (CAD)-domain of P-cadherin are forming ring-like cis dimers. At 2 mm Ca(2+)-associated rings involving two cis dimers indicate trans contacts in electron micrographs. cis and trans interactions were further analyzed by heterodimerization of the ectodomains of E-cadherin (ECAD) and P-cadherin (PCAD) through the leucine zipper domains of c-Jun and c-Fos. ECADJun/ECADFos dimers predominantly form ring-like cis dimers at 1 mm Ca(2+) and double-ringed trans contacts above 2 mm Ca(2+). The Ca(2+)-dependent tetrameric trans contacts of ECADJun/ECADFos dimers are also detectable after chemical cross-linking. Only cis contacts but no trans interactions are observed for heterodimers of ECADFos and the Trp-2 to Ala mutant ECADW2AJun arguing for a decisive role of Trp-2 in trans but not cis interaction. Neither cis nor trans interaction was found for heterodimers of ECADJun and PCADFos suggesting that specificity for homophilic interactions already exists at the level of cis dimerization.

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.

Osteopontin is involved in the initiation of cutaneous contact hypersensitivity by inducing Langerhans and dendritic cell migration to lymph nodes

Osteopontin (OPN) is a chemotactic protein that attracts immune cells, to inflammatory sites. The sensitization phase of allergic cutaneous contact hypersensitivity (CHS) requires the migration of Langerhans cells/dendritic cells (LCs/DCs) from skin to draining lymph nodes. Characterizing OPN function for LC/DC migration we found upregulated OPN expression in hapten sensitized skin and draining lymph nodes. OPN induces chemotactic LC/DC migration, initiates their emigration from the epidermis, and attracts LCs/DCs to draining lymph nodes by interacting with CD44 and alphav integrin. Furthermore, OPN-deficient mice have a significantly reduced CHS response that correlates with an impaired ability of OPN-deficient mice to attract LCs/DCs to draining lymph nodes. In conclusion, OPN is an important factor in the initiation of CHS by guiding LCs/DCs from skin into lymphatic organs.

End-tidal carbon dioxide measurements as a prognostic indicator of outcome in cardiac arrest

PURPOSE

To evaluate the use of end-tidal carbon dioxide values in predicting survival in cardiopulmonary arrest.

BACKGROUND

The decision about when to terminate resuscitative efforts for patients with cardiopulmonary arrest is often subjective. End-tidal carbon dioxide values have been suggested as potential objective criteriafor making this decision.

METHODS

This study was a cooperative effort of the St Louis chapter of the American Association of Critical-Care Nurses and its members and involved 6 hospitals and an air evacuation service. All adult patients who had a cardiopulmonary arrest were eligiblefor the study. Once a patient with cardiac arrest was intubated, end-tidal carbon dioxide and cardiac rhythms were measured and recorded every 5 minutes for 20 minutes or until resuscitation efforts were terminated. Patients' survival at the time of the arrest, survival 24 hours after the arrest, and discharge status were followed up.

RESULTS

A total of 127 patients were enrolled in the study. All but 1 patient with end-tidal carbon dioxide values less than 10 mm Hg died before discharge. End-tidal carbon dioxide values greater than 10 mm Hg were associated with various degrees of survival. Overall survival to discharge was less than 14%, regardless of the end-tidal carbon dioxide value.

CONCLUSION

Measurements of end-tidal carbon dioxide can be used to accurately predict nonsurvival of patients with cardiopulmonary arrest. End-tidal carbon dioxide levels should be monitored during cardiopulmonary arrest and should be considered a useful prognostic value for determining the outcome of resuscitative efforts.

The role of CD44 during CD40 ligand-induced dendritic cell clustering and maturation

The interaction between CD40 on dendritic cells (DC) and its ligand CD154 has been recognized to be an important feature in the maturation of DC. Here, we were interested in the role of CD44 a surface receptor shown to mediate cell-cell adhesion and binding to Hyaluronic acid (HA). Western blot analysis of human DC stimulated for 3-12 h with CD154 revealed the rapid induction of the 85 kDa standard form of CD44 and an increased HA-binding affinity. Time-lapse video-imaging microscopy of human DC co-cultured on CD154-transfected murine fibroblasts showed that the CD44 up-regulation coincided with the rapid induction of homotypic DC clustering, which did not occur on empty vector-transfected fibroblasts. In this system, addition of anti-CD44s mAbs abrogated DC-cluster formation, thereby inhibiting further maturation, as shown by a reduced TNF-alpha production and inhibition of CD154-induced MHC class II up-regulation. However, co-incubation with HA-degrading enzymes induced no changes in the CD154-mediated DC clustering and maturation.

End-tidal carbon dioxide measurements as a prognostic indicator of outcome in cardiac arrest

PURPOSE: To evaluate the use of end-tidal carbon dioxide values in predicting survival in cardiopulmonary arrest. BACKGROUND: The decision about when to terminate resuscitative efforts for patients with cardiopulmonary arrest is often subjective. End-tidal carbon dioxide values have been suggested as potential objective criteriafor making this decision. METHODS: This study was a cooperative effort of the St Louis chapter of the American Association of Critical-Care Nurses and its members and involved 6 hospitals and an air evacuation service. All adult patients who had a cardiopulmonary arrest were eligiblefor the study. Once a patient with cardiac arrest was intubated, end-tidal carbon dioxide and cardiac rhythms were measured and recorded every 5 minutes for 20 minutes or until resuscitation efforts were terminated. Patients' survival at the time of the arrest, survival 24 hours after the arrest, and discharge status were followed up. RESULTS: A total of 127 patients were enrolled in the study. All but 1 patient with end-tidal carbon dioxide values less than 10 mm Hg died before discharge. End-tidal carbon dioxide values greater than 10 mm Hg were associated with various degrees of survival. Overall survival to discharge was less than 14%, regardless of the end-tidal carbon dioxide value. CONCLUSION: Measurements of end-tidal carbon dioxide can be used to accurately predict nonsurvival of patients with cardiopulmonary arrest. End-tidal carbon dioxide levels should be monitored during cardiopulmonary arrest and should be considered a useful prognostic value for determining the outcome of resuscitative efforts.

Recognition of E-cadherin by integrin alpha(E)beta(7): requirement for cadherin dimerization and implications for cadherin and integrin function

We have investigated the importance of dimerization of E-cadherin in the heterophilic adhesive interaction between E-cadherin and integrin alpha(E)beta(7). Dimerization of cadherin molecules in parallel alignment is known to be essential for homophilic adhesion and has been attributed to Ca(2+)-dependent interactions in the domain 1-2 junction or to cross-intercalation of Trp2 from one molecule to the other. We have disrupted either or both of these proposed mechanisms by point mutations in E-cadherin-Fc and have tested the modified proteins for alpha(E)beta(7)-mediated cell adhesion. Prevention of Trp2 intercalation had no adverse effect on integrin-mediated adhesion, whereas disruption of Ca(2+) binding permitted adhesion but with reduced efficiency. Both modifications in combination abolished recognition by alpha(E)beta(7). In EGTA, alpha(E)beta(7) adhered to wild type E-cadherin but not to the Trp2 deletion mutant. Independent evidence that the mutations prevented either or both mechanisms for dimerization is presented. The data show that dimerization is required for recognition by alpha(E)beta(7) and that it can take place by either of two mechanisms. Implications for the roles of the alpha(E) and beta(7) integrin subunits in ligand binding and for Trp2 and Ca(2+) in the assembly of cadherin complexes are discussed.

Soluble CD44 inhibits melanoma tumor growth by blocking cell surface CD44 binding to hyaluronic acid

Proteolytic cleavage of the extracellular domain of CD44 from the surface of cells has been observed recently in different cell types. In cell culture supernatants of human melanoma cell lines a 70 kDa soluble CD44 protein (solCD44) was detected at concentrations of 250-300 ng/ml. Protease inhibitor studies revealed that serine proteases and metalloproteases are involved in the cleavage of CD44 from the surface of melanoma cells. To analyse a possible function of soluble CD44 a human malignant melanoma cell line was stably transfected with cDNAs encoding either wild type soluble CD44s or mutated forms with defective HA binding properties (CD44sR41A and CD44sR150A/R154A). Soluble CD44s almost completely inhibited hyaluronic acid binding by melanoma cells, whereas soluble CD44 mutated in the HA binding domain had no effect. When cultivated on hyaluronic acid, melanoma cell proliferation was induced by 30% for both the parental and the control transfected cells. This increase in proliferation was blocked completely in solCD44s-secreting transfectants, whereas solCD44sR41A and solCD44sR150A/R154A-secreting cells again showed hyaluronic acid-induced cell proliferation. These cell lines were subcutaneously injected into MF1 nu/nu mice to compare their growth as tumors in vivo. Compared to tumors derived from parental and control transfected cells, we observed a dramatic reduction of primary tumor growth with solCD44s expressing MM cells. Transfectants expressing solCD44s mutated in the HA binding domain in contrast developed fast-growing primary tumors. These results provide strong evidence that direct solCD44 interactions with hyaluronic acid interfere competitively with processes induced by hyaluronic acid binding to surface CD44. Autocrine, or drug-induced secretion of solCD44 by human melanoma cells may thus exert potent antitumoral effects in vivo.

New technologies in the assessment of hemodynamic parameters

Pulmonary artery catheter (PAC) use has led to major advances in the assessment of hemodynamics. Since its introduction three decades ago, features have been added to the PAC to enhance its hemodynamic monitoring capabilities. In addition, newer technologies have been proposed to replace the PAC. This article discusses three features that enhance the PAC--measures of mixed venous oxyhemoglobin, right ventricular ejection fraction, and continuous cardiac output--and two newer technologies--esophageal Doppler and exhaled carbon dioxide measurements. The article describes current and future applications of hemodynamic monitoring.

CD44 is the principal mediator of hyaluronic-acid-induced melanoma cell proliferation

Interactions of the extracellular matrix component hyaluronic acid and its cellular receptors CD44 and RHAMM/IHABP have been linked to tumor progression and metastasis formation. We investigated the expression and hyaluronic-acid-dependent functions of CD44 and RHAMM/IHABP in human melanoma. Immunohistochemistry of tumor specimens at different stages of melanoma progression revealed an increased expression of CD44 and RHAMM/IHABP. High mRNA expression of CD44 was found in three highly tumorigenic melanoma cell lines compared with less tumorigenic melanoma cells or nontransformed melanocytes. RHAMM/IHABP expression was upregulated in all cell lines analyzed but not in melanocytes. In contrast to the cell surface localization of CD44, RHAMM/IHABP was detected exclusively within the cytoplasm of melanoma cells. Binding and adhesion of melanoma cells to hyaluronic acid is mainly CD44 dependent as it was inhibited to 60%--80% by an anti-CD44 monoclonal antibody whereas anti-RHAMM/IHABP sera had no effect. Culture of melanoma cells in the presence of hyaluronic acid resulted in a dose-dependent, CD44-mediated increase of melanoma cell proliferation and enhanced release of basic fibroblast growth factor and transforming growth factor beta 1. We conclude that (i) the expression of CD44 and RHAMM/IHABP is increased during melanoma progression, (ii) CD44 is the principal hyaluronic acid surface receptor on melanoma cells, and (iii) the hyaluronic-acid-induced increase of the proliferative capacity of melanoma cells is mainly dependent on CD44--hyaluronic acid interactions.

Controversies in the use of the pulmonary artery catheter

The pulmonary artery catheter (PAC) has been in use for more than 30 years. The amount and detail of hemodynamic information provided by the PAC cannot be matched by any other single technology. Whether or not this information makes a difference in the clinical outcomes of critically ill patients is uncertain, however. The Pulmonary Artery Catheter Consensus Conference scrutinized the available research data on the catheter and provided guidelines for clinicians on its use. This article summarizes the controversy and the guidelines available for use of the PAC. It notes the need for further research on patient outcomes.

Hemodynamic applications of capnography

The measurement of the pressure of exhaled carbon dioxide (PetCO2) via capnography has several useful hemodynamic applications. This article discusses integrating PetCO2 values with hemodynamic assessment. Capnography can be applied to hemodynamic assessment in three key ways: (1) identification of end-expiration during pulmonary artery and central venous pressure measurements, (2) assessment of pulmonary perfusion and alveolar deadspace, (3) assessment of cardiopulmonary resuscitative efforts. The article presents research, sample waveforms for end-expiration identification, and case examples.

Oligosaccharides of hyaluronan are potent activators of dendritic cells

The extracellular matrix component hyaluronan (HA) exists physiologically as a high m.w. polymer but is cleaved at sites of inflammation, where it will be contacted by dendritic cells (DC). To determine the effects of HA on DC, HA fragments of different size were established. Only small HA fragments of tetra- and hexasaccharide size (sHA), but not of intermediate size (m.w. 80, 000-200,000) or high m.w. HA (m.w. 1,000,000-600,000) induced immunophenotypic maturation of human monocyte-derived DC (up-regulation of HLA-DR, B7-1/2, CD83, down-regulation of CD115). Likewise, only sHA increased DC production of the cytokines IL-1beta, TNF-alpha, and IL-12 as well as their allostimulatory capacity. These effects were highly specific for sHA, because they were not induced by other glycosaminoglycans such as chondroitin sulfate or heparan sulfate or their fragmentation products. Interestingly, sHA-induced DC maturation does not involve the HA receptors CD44 or the receptor for hyaluronan-mediated motility, because DC from CD44-deficient mice and wild-type mice both responded similarly to sHA stimulation, whereas the receptor for hyaluronan-mediated motility is not detectable in DC. However, TNF-alpha is an essential mediator of sHA-induced DC maturation as shown by blocking studies with a soluble TNFR1. These findings suggest that during inflammation, interaction of DC with small HA fragments induce DC maturation.

Clinical application. Using oxygenation profiles to manage patients

Cellular oxygenation is dependent on both tissue oxygenation and pulmonary oxygenation. The use of profiles can help to make the assessment of tissue and pulmonary oxygenation more thorough. Although oxygenation profiles have limitations, an understanding of them can provide useful information to the critical care nurse. Oxygenation profiles enable the nurse to trend a patient's progress and response to nursing and medical interventions. A sophisticated assessment relies not merely on physical assessment alone but incorporates continuous mixed venous oxygenation and oxygenation profiles to assess a patient's tissue and pulmonary oxygenation status.

Capnography. A key underutilized technology

Based on the multiple applications and the potential cost savings, every ICU should have enough capnography for all intubations and probably for all mechanically ventilated patients. Of the multiple clinical applications of capnography, most attention should be focused on its use with intubation and resuscitation. Other applications, such as blood gas and ventilation-perfusion scan reduction, should be instituted after the primary areas have been implemented. While capnography modules may appear to be expensive at first glance, an analysis of their clinical application reveals they can save the hospital hundreds of thousands of dollars beyond the purchase price.

Outlier management. Influencing the highest resource-consuming areas in acute and critical care

Outliers account for a large amount of technology utilization and resources consumed in acute care, despite accounting for only a small portion of the total patient population. Most current efforts to reduce costs, such as re-engineering and downsizing, are nonspecific methods of controlling costs. Focusing efforts in high-cost areas, such as outlier management, is much more likely to improve patient care and improve the use of technology while achieving real advances in cost control. Most hospitals will have to build an infrastructure to support outlier management, which includes developing clinical staff. These processes will take time and careful planning, but they are essential for the effective management of technology utilization and outliers. The failure to employ focused efforts like outlier management will result in the superficial treatment of high costs in acute care. The benefit to employing these methods leads to the best use of technology and the improved management of a difficult patient population.

Pulse oximetry

Pulse oximetry is one of the most commonly applied technologies in acute and critical care. It has the potential to continuously monitor pulmonary function, avoid unnecessary blood gases, and alert clinicians to hypoxemic events that are not readily apparent by physical assessment. Due to these advantages, pulse oximetry has a firm place in health care. Unfortunately, pulse oximetry will not usually have a major impact on reducing hospital resources. In addition, oximetry has the potential to be misused owing to its widespread application. In order to obtain the maximum benefits from this technology, clinicians must be educated about the strengths and limitations of oximetry. If this education effectively changes clinicians' behavior, pulse oximetry will provide an excellent clinical advantage in patient assessment as well as moderate cost benefits.

Continuous mixed venous (SvO2) monitoring. Too expensive or indispensible?

Based on theoretic principles and clear literature support, SvO2 (mixed venous oxyhemoglobin) monitoring offers an important advantage over traditional hemodynamic parameters. SvO2 allows more precise understanding of the adequacy of cardiac and pulmonary function than traditional parameters. SvO2 values do not replace the need to measure individual parameters of oxygen delivery or consumption but serves as the standard for assessing the impact of each parameter on tissue oxygenation. SvO2 has the ability to reflect a threat to tissue oxygenation that is unmatched by other parameters. Its ability to give a real time indication of tissue oxygenation makes it a preferred parameter for monitoring the adequacy of hemodynamics. Its use as an end point for determining the adequacy of hemodynamics (BP, CO/CI), measurement of Qs/Qt, and prediction of potential hemodynamic instability make this parameter invaluable for the knowledgeable clinician. SvO2 catheters cost more than traditional PA catheters, a factor that has limited their acceptance as the standard PA catheter. The added cost of the SvO2 catheter has not been adequately addressed in the research literature. However, research does support SvO2 allows more rapid termination of drug therapies, may improve movement out of the ICU, and reduces the incidence of mechanical ventilator manipulation. These features increase the cost-effectiveness of SvO2 catheters. The cost-effectiveness of the catheter, like any technology, is predicated on the clinician. Clinicians++ must be educated to use SvO2 as a primary end point for treatment decisions regarding hemodynamic therapy and patient stability. If used properly, every PAC should use fiberoptic SvO2 capabilities.

Hemodynamic monitoring

Hemodynamic monitoring is one of the most exciting and potentially useful technologies in critical care. Hemodynamic monitoring, particularly the PAC, is the technology most often associated with the critical care unit. However, it is a difficult technology to master and is associated with clear (although infrequent) serious complications. It can also be associated with increased costs. With appropriate implementation, this technology can improve patient outcome and moderately reduce costs. Appropriate implementation is not easy with this technology. This type of technology should only be employed in hospitals willing to invest the education and quality monitoring to ensure its appropriate application. As a part of this infrastructure, physicians and nurses need frequent communication in terms of what is expected from this technology for each patient.