Bloodstream cells phenotypically identical to human mesenchymal bone marrow stem cells circulate in large amounts under the influence of acute large skin damage: new evidence for their use in regenerative medicine

OBJECTIVES

Recent work has shown that human bone marrow contains mesenchymal stem cells (MSCs). However, little is known about their presence in peripheral blood. Since these cells are potentially responsible for tissue repair after injury, their number should be increased during these situations. To demonstrate their number during these situations, we measured MSCs in the peripheral blood of healthy donors and burn patients.

MATERIALS AND METHODS

Blood samples were obtained from 15 acute burn patients and 15 healthy donors. We performed flow cytometric analysis, using a large monoclonal antibody panel: CD44, CD45, CD14, DR, CD34, CD19, CD13, CD29, CD105, CD1a, CD90, CD38, CD25. MSC phenotype was considered positive for CD44, CD13, CD29, CD90, and CD105, and negative for the other monoclonals. The testing was performed on day 3 after injury. We correlated the results with the age, sex, and size and type of burns.

RESULTS

Cells expressing the MSC phenotype were detected in the peripheral blood of both groups. Noteworthy, compared with samples from healthy donors (0.0078 +/- 0.0044), blood obtained from burn patients showed a higher MSC percentage (0.1643 +/- 0.115; P < .001). The percentage of MSCs correlated with the size and severity of the burn. Increased values were also observed among younger patients.

CONCLUSIONS

MSCs have an important role in regenerative processes of human tissues. We found cells phenotypically identical to MSCs circulating in physiological number in normal subjects, but in significantly higher amounts during acute large burns. Therefore, they may represent a previously unrecognized circulatory component to the process of skin regeneration.

Promoting health care safety through training high reliability teams

Many organizations have been using teams as a means of achieving organizational outcomes (such as productivity and safety). Research has indicated that teams, especially those operating in complex environments, are not always effective. There is a subset of organizations in which teams operate that are able to balance effectiveness and safety despite the complexities of the environment (for example, aviation, nuclear power). These high reliability organizations (HROs) have begun to be examined as a model for those in other complex domains, such as health care, that strive to reach a status of high reliability. In this paper we analyse the components leading to the effectiveness of HROs by examining the teams that comprise them. We use a systems perspective to uncover the behavioral markers by which high reliability teams (HRTs) are able to uphold the values of their parent organizations, thereby promoting safety. Using these markers, we offer guidelines and developmental strategies that will help the healthcare community to shift more quickly to high reliability status by not focusing solely on the organizational level.

Isolation of flavanol-anthocyanin adducts by countercurrent chromatography

Pigments of the flavanol-anthocyanin (F-A+) type detected earlier in wine are synthesized using a protocol adapted from the synthesis of procyanidin dimers. The F-A+ adduct thus obtained is purified by countercurrent liquid-liquid partition, currently referred to as countercurrent chromatography (CCC). The solvent system consists of tert-butyl methyl ether-n-butanol-acetonitrile-water (2:2:1:5, acidified with 0.1% trifluoroacetyl) with the light organic phase acting as a stationary phase and the aqueous phase as the mobile phase. Four fractions are recovered and analyzed by high-performance liquid chromatography coupled to a diode-array detector and electrospray ionization mass spectrometer. The multilayer CCC method allowed the separation of pigments in three different groups. The first group consists of hydrosoluble pigments present in fraction 1; the second group consists of the F-A+ adducts [catechin-malvidin 3 glucoside (Mv3glc), along with some (catechin)2-Mv3glc]; and the third group is their anthocyanin precursor, Mv3glc.

Human mesenchymal stem cells are tolerized by mice and improve skin and spinal cord injuries

INTRODUCTION

We sought to use human mesenchymal stem cells (HMSC) for skin and spinal cord repair in mice.

MATERIALS AND METHODS

Human bone marrow obtained from a young healthy donor was used to separate and culture human mesenchymal stem cells (HMSC). Ten mice were included in each of four groups. A full-thickness skin defect was surgically performed on all mice in groups 1 and 2. A transverse complete medullar section was performed in groups 3 and 4. Groups 1 and 3 received HMSC IV infusion and local HMSC polymer implant. Groups 2 and 4 received only the IV HMSC infusion. Five control animals from each group went through the same lesions but they didn't receive treatment.

RESULTS

After local administration of HMSC into the fibrin polymer combined with the IV infusion of HMSC, there was no immune rejection; all skin defects healed without scar or retraction at a median time of 14 days. Sixty percent of the animals treated with IV infusion and polymer with HMSC simultaneously had improved neurological activities, while all control mice with spinal cord injury experiments died or perpetuated their paralysis with worsening muscular atrophy and increasing propensity to skin damage.

CONCLUSIONS

HMSC are not immunologically reactive and can trespass species defense barriers. Animals treated with these cells repaired injuries better than controls. In this way we propose that universal HMSC from donors can be cultured, expanded, and cryopreserved to be used in human organ or tissue regeneration.

Effects of a novel platelet nitric oxide donor (LA816), aspirin, clopidogrel, and combined therapy in inhibiting flow- and lesion-dependent thrombosis in the porcine ex vivo model

BACKGROUND

Acetylsalicylic acid (ASA), or aspirin, plus clopidogrel is becoming the standard antithrombotic treatment in people with coronary disease. Novel approaches such as the use of platelet-selective nitric oxide (NO) donors may provide additional protection against thrombosis. We evaluated the antithrombotic properties of a novel platelet-selective NO donor (LA816) administered alone and in combination with ASA, clopidogrel, or ASA+clopidogrel.

METHODS AND RESULTS

Thrombogenicity was measured in the porcine experimental model and assessed as platelet-thrombus formation in the ex vivo Badimon perfusion chamber. Pigs were randomly divided into 4 groups: (1) placebo control, (2) clopidogrel, (3) ASA, and (4) ASA+clopidogrel (ASA and clopidogrel were given orally, 10 mg x kg(-1) x d(-1) for 3 d). The animals were anesthetized, heparinized, and catheterized, and the Badimon perfusion chamber was placed in an extracorporeal shunt. After baseline perfusions, all animal groups received the intravenous infusion of LA816 for 2 hours. Platelet aggregation, blood pressure, and heart rate also were evaluated during the experiments. LA816, clopidogrel, and ASA+clopidogrel produced a reduction of approximately 45% on thrombus mass versus placebo control perfusions (P<0.05). Combined treatment of oral ASA+clopidogrel and intravenous LA816 produced a significant further reduction of 25% in platelet deposition (70% from placebo controls; P<0.0001). LA816 intravenous treatment did not modify blood pressure or heart rate.

CONCLUSIONS

Acute NO donation with LA816, without modifying hemodynamic parameters, provides the same inhibitory effect as that obtained with chronic treatment with clopidogrel+ASA. Moreover, LA816 provides platelet inhibitory effects in addition to those of the combined blockade of cyclooxygenase and P2y(12) receptor.

How to turn a team of experts into an expert medical team: guidance from the aviation and military communities

There is no question that interdisciplinary teams are becoming ubiquitous in healthcare. It is also true that experts do not necessarily combine to make an expert team. However when teams work well they can serve as adaptive systems that allow organisations to mitigate errors within complex domains, thereby increasing safety. The medical community has begun to recognise the importance of teams and as such has begun to implement team training interventions. Over the past 20 years the military and aviation communities have made a large investment in understanding teams and their requisite training requirements. There are many lessons that can be learned from these communities to accelerate the impact of team training within the medical community. Therefore, the purpose of the current paper is to begin to translate some of the lessons learned from the military and aviation communities into practical guidance that can be used by the medical community.

How to turn a team of experts into an expert medical team: guidance from the aviation and military communities

There is no question that interdisciplinary teams are becoming ubiquitous in healthcare. It is also true that experts do not necessarily combine to make an expert team. However when teams work well they can serve as adaptive systems that allow organisations to mitigate errors within complex domains, thereby increasing safety. The medical community has begun to recognise the importance of teams and as such has begun to implement team training interventions. Over the past 20 years the military and aviation communities have made a large investment in understanding teams and their requisite training requirements. There are many lessons that can be learned from these communities to accelerate the impact of team training within the medical community. Therefore, the purpose of the current paper is to begin to translate some of the lessons learned from the military and aviation communities into practical guidance that can be used by the medical community.

Quantitative ultrasound calcaneus measurements: normative data and precision in the spanish population

Quantitative ultrasound (QUS) assessment at the calcaneus has been found to be a safe and reliable method for evaluating skeletal status. In this study we have determined the normative QUS data in the Spanish population for the Sahara Clinical Sonometer (Hologic). Broadband ultrasound attenuation (BUA), speed of sound (SOS), quantitative ultrasound index (QUI) and estimated bone mineral density (BMD) were determined. We also studied the precision in vivo and in vitro. The short-term in vivo precision (CV) was 4.88% for BUA, 0.36% for SOS, 3.45% for QUI and 4.15% for BMD, while in vitro precision was 0.40% for SOS and 2.67% for BUA. Our results are comparable to reference population data previously published in other countries and may serve as reference normative data for both genders in Spain.

The role of trainee knowledge structures in aviation team environments

The importance of having well-developed knowledge structures to enhance complex team performance has been recently indicated in the training effectiveness literature. This work tested that proposition within an aviation team training setting. Results suggested that aviation team training improved the knowledge structures of those participants who received the training. Knowledge structure data also provided information related to the training that was not available from more traditional measures of learning. Finally, results obtained from the knowledge structure measures were consistent with performance results, suggesting that knowledge structure measures are a potentially valid predictor of performance.

Enhancing transfer of training: using role-play to foster teamwork in the cockpit

Role-plays serve a unique purpose in providing practice and feedback for aircrew team development training in the classroom. When compared with other training strategies, role-play provides targeted practice and feedback of specific behaviors at low cost, with the trade-off being the amount of fidelity it provides. This article presents guidelines for designing role-plays to elicit crew resource management (CRM) behaviors and providing feedback to trainees on their performance. Through careful design procedures, a role-play exercise can provide both targeted practice and feedback and serve a useful purpose in the overall training design of a CRM training program.

Automation, task difficulty, and aircrew performance

The effects of an automated system on team processes and performance were assessed in a laboratory simulation. Two-person crews were required to fly a complex emergency-response scenario under conditions of low and high workload. These flights were completed with or without the aid of an autopilot. The results indicated that the autopilot was effective in reducing subjective workload. However, the automation was associated with improved performance on only 1 of 4 performance measures. Furthermore, it was observed that problem-solving performance was worse in the autopilot condition during the high-workload flights. Investigation of crew process data indicated that workload savings afforded by the autopilot might have been invested in more explicit coordination. The results are discussed in terms of their implications for military aviators' performance, system design, and team training.

Analyzing team performance: in the eye of the beholder?

The effect of team-member experience was examined in relation to perceptions of importance of teamwork behaviors during an analysis of team performance. Importance ratings were collected from military aircrews (i.e., two-member teams) from three distinct types of aircraft. Results indicated that when assessing team behavior importance, less experienced team members weighted difficulty of performing team behaviors more heavily, whereas more experienced team members weighted time spent performing team behaviors more heavily. Implications for analyzing team performance, with respect to the process of conducting such analyses and the type of information collected, are discussed.

It is not how much you have but how you use it: toward a rational use of simulation to support aviation training

One of the most remarkable changes in aviation training over the past few decades is the use of simulation. The capabilities now offered by simulation have created unlimited opportunities for aviation training. In fact, aviation training is now more realistic, safe, cost-effective, and flexible than ever before. However, we believe that a number of misconceptions--or invalid assumptions--exist in the simulation community that prevent us from fully exploiting and utilizing recent scientific advances in a number of related fields in order to further enhance aviation training. These assumptions relate to the overreliance on high-fidelity simulation and to the misuse of simulation to enhance learning of complex skills. The purpose of this article is to discuss these assumptions in the hope of initiating a dialogue between behavioral scientists and engineers.

The science of training: a decade of progress

This chapter reviews the training research literature reported over the past decade. We describe the progress in five areas of research including training theory, training needs analysis, antecedent training conditions, training methods and strategies, and posttraining conditions. Our review suggests that advancements have been made that help us understand better the design and delivery of training in organizations, with respect to theory development as well as the quality and quantity of empirical research. We have new tools for analyzing requisite knowledge and skills, and for evaluating training. We know more about factors that influence training effectiveness and transfer of training. Finally, we challenge researchers to find better ways to translate the results of training research into practice.

Matrix metalloproteinase-2 in platelet adhesion to fibrinogen: interactions with nitric oxide

BACKGROUND

Matrix metalloproteinase-2 (MMP-2) has been shown to activate a non-thromboxane, non-ADP pathway of platelet aggregation. In contrast, nitric oxide (NO) is known to inhibit platelet adhesion and aggregation. Therefore, we have studied the release of MMP-2 during platelet adhesion to fibrinogen, the effects of phenanthrolione, an MMP-2 inhibitor, on adhesion and the interactions of inhibitor with a NO donor, S-nitroso-N-acetyl-D, L-penicillamine (SNAP).

MATERIAL AND METHODS

Human platelets were isolated from blood of healthy volunteers and platelet adhesion to fibrinogen-coated plates was studied by measuring thrombin-stimulated release of platelet a-granule constituent, platelet factor 4. In addition, the mode of action of phenanthroline and NO on platelets was investigated by assaying the levels of intraplatelet cyclic GMP.

RESULTS

Thrombin-stimulated platelet adhesion to fibrinogen was associated with increased release of MMP-2 from platelets. Phenanthroline (0.1-100 KM) reduced platelet adhesion to fibrinogen. The adhesion was also inhibited by SNAP (0.1-100 KM), an effect abolished by 1H-[1,2,4] oxadiazolol [4,3,-a] quinoxalin-1-one (ODQ), a selective inhibitor of the soluble guanylate cyclase. Co-administration of phenanthroline and SNAP resulted in a synergistic inhibition of platelet adhesion, an effect that was not associated with enhanced cyclic GMP generation by platelets. Furthermore, ODQ did not reverse the synergistic effect of these compounds on adhesion.

CONCLUSIONS

1. MMP-2 promotes platelet adhesion to fibrinogen. 2. Phenanthroline and NO synergize to inhibit platelet adhesion to fibrinogen acting through a cyclic GMP-independent mechanism(s).

To transfer or not to transfer? Investigating the combined effects of trainee characteristics, team leader support, and team climate

Eighty pilots participated in a study of variables influencing the transfer process. Posttraining performance was assessed in a flight simulation under 1 of 2 conditions. Those in the maximum performance condition were made aware of the skill to be assessed and the fact that their teammates were confederates, whereas those in the typical performance condition were not. The results indicated that (a) simulator ratings correlated with a measure of transfer to the cockpit for those in the typical condition only; (b) team leader support, manipulated in a pretask brief, moderated the disparity between maximum and typical performance; (c) team climate mediated the impact of support on performance in the typical condition; (d) those with a stronger predisposition toward the trained skill viewed their climate as more supportive; and (e) perceptions of team climate were better predictors of performance for those with a more external locus of control.

Team training in the skies: does crew resource management (CRM) training work?

The aviation community has invested great amounts of money and effort into crew resource management (CRM) training. Using D. L. Kirkpatrick's (1976) framework for evaluating training, we reviewed 58 published accounts of CRM training to determine its effectiveness within aviation. Results indicated that CRM training generally produced positive reactions, enhanced learning, and promoted desired behavioral changes. However, we cannot ascertain whether CRM has an effect on an organization's bottom line (i.e., safety). We discuss the state of the literature with regard to evaluation of CRM training programs and, as a result, call for the need to conduct systematic, multilevel evaluation efforts that will show the true effectiveness of CRM training. As many evaluations do not collect data across levels (as suggested by D. L. Kirkpatrick, 1976, and by G. M. Alliger, S. I. Tannenbaum, W. Bennett, Jr., & H. Traver, 1997), the impact of CRM cannot be truly determined; thus more and better evaluations are needed and should be demanded.

What determines whether observers recognize targeted behaviors in modeling displays?

Observational learning is based on a critical assumption that trainees can and do recognize critical modeled behaviors. This assumption has been virtually untested in applied settings. We studied the effects of work experience and instructions on the ability of 59 observers to recognize target behaviors in an observational learning paradigm similar to existing ones. Additionally, we investigated the effects of two key factors that were hypothesized to affect the recognition process in observational learning. The results indicated that only observers who had a minimum of work experience (i.e., intermediate and experienced observers in the study) were able to consistently recognize targeted behaviors. Additionally, recognition was influenced by the level of detail of instructions given to the participants. Finally, characteristics of the modeled behaviors greatly affected recognition: Overall, examples of negative behaviors were better recognized than were positive examples. Behaviors whose consequence was shown were also better recognized than those that were neither reinforced nor punished in the video. The results are discussed in terms of their implications for the design of observational learning as a training strategy in complex and applied social learning situations. The applications of this work include the design of training, and the training of evaluators and observers.

Does stress training generalize to novel settings?

Many high-stress task environments are complex and dynamic, and it is often difficult during training to anticipate the exact conditions that may be encountered in these settings. We conducted an empirical study to examine whether the positive effects of stress training that addressed one specific type of stressor and task would remain when trainees performed under a novel stressor or performed a novel task. Participants performed a laboratory task under stress conditions. Measures of task performance and self-reported stress were obtained at three performance trials: (a) prior to stress training, (b) after a stress training intervention targeted to that specific task environment, and (c) under novel stressor/task conditions. Results indicated that the beneficial effects of stress training were retained when participants performed under a novel stressor and performed a novel task. We discuss the implications of this study with regard to their application in the design of stress training and the transfer of learning to complex, dynamic task environments.

Teamwork in multi-person systems: a review and analysis

As the scope and complexity of modern task demands exceed the capability of individuals to perform, teams are emerging to shoulder the burgeoning requirements. Accordingly, researchers have striven to understand and enhance human performance in team settings. The purpose of this review is to summarize that research, from the theoretical underpinnings that drive it, to the identification of team-level elements of success, to the methodologies and instruments that capture and measure those characteristics. Further specified are three important avenues to creating successful teams: team selection, task design and team training. In other words, one can select the right people, provide them with a task engineered for superior performance and train them in the appropriate skills to accomplish that task. Under task design, new technologies and automation are examined that both support and impede team functioning. Finally, throughout are provided critical remarks about what is known about teamwork and what is needed to be known to move the science and practice of team performance forward. The paper concludes with the identification of team issues that require further investigation.

The mechanisms of platelet dysfunction during extracorporeal membrane oxygenation in critically ill neonates

OBJECTIVE

Although bleeding associated with thrombocytopenia often complicates extracorporeal membrane oxygenation (ECMO), the mechanisms of platelet dysfunction during ECMO remain poorly understood. We investigated the role of matrix metalloproteinase (MMP)-2, which recently has been shown to mediate a novel pathway of platelet aggregation, in the platelet dysfunction induced by ECMO.

DESIGN

Prospective longitudinal case study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Ten neonates treated with ECMO.

INTERVENTION

ECMO procedure.

MEASUREMENTS

Platelet counts and collagen-induced platelet aggregation ex vivo; plasma markers of platelet (soluble P-selectin) and endothelial (soluble E-selectin and total nitrite/nitrate) activation; plasma MMP-2 and MMP-9 activities; and concentrations of tissue inhibitors of MMPs.

MAIN RESULTS

During ECMO, time-dependent platelet activation, as evidenced by thrombocytopenia, decreased platelet aggregation, and increased plasma soluble P-selectin concentrations were found in the absence of endothelial activation, as shown by normal plasma concentrations of soluble E-selectin and nitric oxide metabolites (nitrite/nitrate). There was a time-dependent increase in plasma MMP-2 but not MMP-9 activity; tissue inhibitors of MMPs were not detected. Plasma soluble P-selectin concentrations significantly correlated with simultaneous plasma MMP-2 (r2 = .37, p < .0001) but not with MMP-9 activities. Platelet dysfunction persisted despite repeated platelet transfusions to maintain platelet counts >100 x 10(9)/L.

CONCLUSIONS

ECMO resulted in the activation of platelets but not endothelial cells. During ECMO, platelet dysfunction persisted despite platelet transfusions. MMP-2 may play a role in the development of platelet dysfunction caused by ECMO.