Effectiveness of permissive weight bearing in surgically treated trauma patients with peri- and intra-articular fractures of the lower extremities: a prospective comparative multicenter cohort study.

PURPOSE: The aim of the present study was to investigate the effectiveness of a novel approach involving permissive weight bearing (PWB) in surgically treated trauma patients with peri- and intra-articular fractures of the lower extremities. METHODS: Prospective comparative multicenter cohort study in one level 1 trauma center and five level 2 trauma centers. Surgically treated trauma patients with peri- and intra-articular fractures of the lower extremities were included. Permissive weight bearing (PWB) in comparison to restricted weight bearing (RWB) was assessed over a 26-week post-surgery follow-up period. Patients' self-perceived outcome levels regarding activities of daily living (ADL), quality of life (QoL), pain and weight bearing compliance were used. RESULTS: This study included 106 trauma patients (N = 53 in both the PWB and RWB groups). Significantly better ADL and QoL were found in the PWB group compared to the RWB group at 2-, 6-, 12- and 26-weeks post-surgery. There were no significant differences in postoperative complication rates between the PWB and RWB groups. CONCLUSION: PWB is effective and is associated with a significantly reduced time to full weight bearing, and a significantly better outcome regarding ADL and QoL compared to patients who followed RWB regimen. Moreover, no significant differences in complication rates were found between the PWB and RWB groups. LEVEL OF EVIDENCE: Level II. REGISTRATION: This study is registered in the Dutch Trial Register (NTR6077). Date of registration: 01-09-2016.

Elucidating the Structure and Composition of Individual Bimetallic Nanoparticles in Supported Catalysts by Atom Probe Tomography.

Understanding and controlling the structure and composition of nanoparticles in supported metal catalysts are crucial to improve chemical processes. For this, atom probe tomography (APT) is a unique tool, as it allows for spatially resolved three-dimensional chemical imaging of materials with sub-nanometer resolution. However, thus far APT has not been applied for mesoporous oxide-supported metal catalyst materials, due to the size and number of pores resulting in sample fracture during experiments. To overcome these issues, we developed a high-pressure resin impregnation strategy and showcased the applicability to high-porous supported Pd-Ni-based catalyst materials, which are active in CO2 hydrogenation. Within the reconstructed volume of 3 × 105 nm3, we identified over 400 Pd-Ni clusters, with compositions ranging from 0 to 16 atom % Pd and a size distribution of 2.6 ± 1.6 nm. These results illustrate that APT is capable of quantitatively assessing the size, composition, and metal distribution for a large number of nanoparticles at the sub-nm scale in industrial catalysts. Furthermore, we showcase that metal segregation occurred predominately between nanoparticles, shedding light on the mechanism of metal segregation. We envision that the presented methodology expands the capabilities of APT to investigate porous functional nanomaterials, including but not limited to solid catalysts.

Arginine Availability in Reamed Intramedullary Aspirate as Predictor of Outcome in Nonunion Healing.

Fracture healing and nonunion development are influenced by a range of biological factors. Adequate amino acid concentrations, especially arginine, are known to be important during normal bone healing. We hypothesize that bone arginine availability in autologous bone marrow grafting, when using the reamer-irrigator-aspirator (RIA) procedure, is a marker of bone healing capacity in patients treated for nonunion. Seventeen patients treated for atrophic long bone nonunion by autologous bone grafting by the RIA procedure were included and divided into two groups, successful treatment of nonunion and unsuccessful, and were compared with control patients after normal fracture healing. Reamed bone marrow aspirate from a site distant to the nonunion was obtained and the amino acids and enzymes relevant to arginine metabolism were measured. Arginine and ornithine concentrations were higher in patients with successful bone healing after RIA in comparison with unsuccessful healing. Ornithine concentrations and arginase-1 expression were lower in all nonunion patients compared to control patients, while citrulline concentrations were increased. Nitric oxide synthase 2 (Nos2) expression was significantly increased in all RIA-treated patients, and higher in patients with a successful outcome when compared with an unsuccessful outcome. The results indicate an influence of the arginine-nitric oxide metabolism in collected bone marrow, on the outcome of nonunion treatment, with indications for a prolonged inflammatory response in patients with unsuccessful bone grafting therapy. The determination of arginine concentrations and Nos2 expression could be used as a predictor for the successful treatment of autologous bone grafting in nonunion treatment.

Intercellular delivery of therapeutic oligonucleotides.

One promising approach to cancer therapeutics is to induce changes in gene expression that either reduce cancer cell proliferation or induce cancer cell death. Therefore, delivering oligonucleotides (siRNA/miRNA) that target specific genes or gene programs might have a potential therapeutic benefit. The aim of this study was to examine the potential of cell-based delivery of oligonucleotides to cancer cells via two naturally occurring intercellular pathways: gap junctions and vesicular/exosomal traffic. We utilized human mesenchymal stem cells (hMSCs) as delivery cells and chose to deliver in vitro two synthetic oligonucleotides, AllStars HS Cell Death siRNA and miR-16 mimic, as toxic (therapeutic) oligonucleotides targeting three cancer cell lines: prostate (PC3), pancreatic (PANC1) and cervical (HeLa). Both oligonucleotides dramatically reduced cell proliferation and/or induced cell death when transfected directly into target cells and delivery hMSCs. The delivery and target cells we chose express gap junction connexin 43 (Cx43) endogenously (PC3, PANC1, hMSC) or via stable transfection (HeLaCx43). Co-culture of hMSCs (transfected with either toxic oligonucleotide) with any of Cx43 expressing cancer cells induced target cell death (~20% surviving) or senescence (~85% proliferation reduction) over 96 hours. We eliminated gap junction-mediated delivery by using connexin deficient HeLaWT cells or knocking out endogenous Cx43 in PANC1 and PC3 cells via CRISPR/Cas9. Subsequently, all Cx43 deficient target cells co-cultured with the same toxic oligonucleotide loaded hMSCs proliferated, albeit at significantly slower rates, with cell number increasing on average ~2.2-fold (30% of control cells) over 96 hours. Our results show that both gap junction and vesicular/exosomal intercellular delivery pathways from hMSCs to target cancer cells deliver oligonucleotides and function to either induce cell death or significantly reduce their proliferation. Thus, hMSC-based cellular delivery is an effective method of delivering synthetic oligonucleotides that can significantly reduce tumor cell growth and should be further investigated as a possible approach to cancer therapy.

Lens Connexin Channels Show Differential Permeability to Signaling Molecules.

Gap junction channels mediate the direct intercellular passage of small ions as well as larger solutes such as second messengers. A family of proteins called connexins make up the subunits of gap junction channels in chordate animals. Each individual connexin forms channels that exhibit distinct permeability to molecules that influence cellular signaling, such as calcium ions, cyclic nucleotides, or inositol phosphates. In this review, we examine the permeability of connexin channels containing Cx43, Cx46, and Cx50 to signaling molecules and attempt to relate the observed differences in permeability to possible in vivo consequences that were revealed by studies of transgenic animals where these connexin genes have been manipulated. Taken together, these data suggest that differences in the permeability of individual connexin channels to larger solutes like 3',5'-cyclic adenosine monophosphate (cAMP) and inositol 1,4,5-trisphosphate (IP3) could play a role in regulating epithelial cell division, differentiation, and homeostasis in organs like the ocular lens.

A study of the outward background current conductance gK1, the pacemaker current conductance gf, and the gap junction conductance gj as determinants of biological pacing in single cells and in a two-cell syncytium using the dynamic clamp.

We previously demonstrated that a two-cell syncytium, composed of a ventricular myocyte and an mHCN2 expressing cell, recapitulated most properties of in vivo biological pacing induced by mHCN2-transfected hMSCs in the canine ventricle. Here, we use the two-cell syncytium, employing dynamic clamp, to study the roles of gf (pacemaker conductance), gK1 (background K+ conductance), and gj (intercellular coupling conductance) in biological pacing. We studied gf and gK1 in single HEK293 cells expressing cardiac sodium current channel Nav1.5 (SCN5A). At fixed gf, increasing gK1 hyperpolarized the cell and initiated pacing. As gK1 increased, rate increased, then decreased, finally ceasing at membrane potentials near EK. At fixed gK1, increasing gf depolarized the cell and initiated pacing. With increasing gf, rate increased reaching a plateau, then decreased, ceasing at a depolarized membrane potential. We studied gj via virtual coupling with two non-adjacent cells, a driver (HEK293 cell) in which gK1 and gf were injected without SCN5A and a follower (HEK293 cell), expressing SCN5A. At the chosen values of gK1 and gf oscillations initiated in the driver, when gj was increased synchronized pacing began, which then decreased by about 35% as gj approached 20 nS. Virtual uncoupling yielded similar insights into gj. We also studied subthreshold oscillations in physically and virtually coupled cells. When coupling was insufficient to induce pacing, passive spread of the oscillations occurred in the follower. These results show a non-monotonic relationship between gK1, gf, gj, and pacing. Further, oscillations can be generated by gK1 and gf in the absence of SCN5A.

Lens Connexin Channels Have Differential Permeability to the Second Messenger cAMP.

Purpose: Gap junction channels exhibit connexin specific biophysical properties, including the selective intercellular passage of larger solutes, such as second messengers. Here, we have examined the cyclic nucleotide permeability of the lens connexins, which could influence events like epithelial cell division and differentiation. Methods: We compared the cAMP permeability through channels composed of Cx43, Cx46, or Cx50 using simultaneous measurements of junctional conductance and intercellular transfer. For cAMP detection, the recipient cells were transfected with a cAMP sensor gene, the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH). cAMP was introduced via patch pipette into the cell of the pair that did not express SpIH. SpIH-derived currents were recorded from the other cell of a pair that expressed SpIH. cAMP permeability was also directly visualized in transfected cells using a chemically modified fluorescent form of the molecule. Results: cAMP transfer was observed for homotypic Cx43 channels over a wide range of junctional conductance. Homotypic Cx46 channels also transferred cAMP, but permeability was reduced compared with Cx43. In contrast, homotypic Cx50 channels exhibited extremely low permeability to cAMP, when compared with either Cx43, or Cx46. Conclusions: These data show that channels made from Cx43 and Cx46 result in the intercellular delivery of cAMP in sufficient quantity to activate cyclic nucleotide-modulated channels. The data also suggest that the greatly reduced cAMP permeability of Cx50 channels could play a role in the regulation of cell division in the lens.

Evidence-based rehabilitation therapy following surgery for (peri-)articular fractures: A systematic review.

OBJECTIVE: To assess the availability of explicitly reported protocols describing post-surgery rehabilitation of (peri-)articular fractures of the proximal humerus, acetabulum and/or tibial plateau, and to critically review any scientific evidence on the effectiveness of these protocols. DATA SOURCES: MEDLINE (PubMed), Cochrane databases, CINAHL, PEDro and Embase (Ovid) were searched to November 2018. Furthermore, stakeholder internet sites, clinical guidelines and standard textbooks were searched. STUDY SELECTION: Screening was performed independently by 2 researchers based on a priori defined eligibility criteria. DATA SYNTHESIS: Five papers addressed post-surgical rehabilitation of proximal humerus fractures, 1 paper that of acetabulum fractures. No eligible information was found on stakeholder sites or in standard textbooks. Overall, the main focus of the protocols identified was on the International Classification of Functioning, Disability and Health (ICF) Body Functions and Structures level. In general, little information about therapy dosage was reported. None of the protocols provided scientific evidence on which the content of described rehabilitation programmes was based. CONCLUSION: This review reveals a paucity of explicitly formulated protocols focussing on post-surgical rehabilitation of common (peri-)articular fractures targeting patient-centred care at all ICF levels. There is a need for more scientific evidence on which to base protocols regarding common (peri-)articular fracture rehabilitation.

Redesigning an International Orthopaedic CME Course: The Effects on Participant Engagement over 5 Years.

The time required to observe changes in participant evaluation of continuing medical education (CME) courses in surgical fields is unclear. We investigated the time required to observe changes in participant evaluation of an orthopaedic course after educational redesign using aggregate course-level data obtained from 1359 participants who attended one of 23 AO Davos Courses over a 5-year period between 2007 and 2011. Participants evaluated courses using two previously validated, 5-point Likert scales based on content and faculty performance, and we compared results between groups that underwent educational redesign incorporating serial needs assessment, problem-based learning, and faculty training initiatives (Masters Course), and those that did not (Non-Masters Course). Average scores for the usefulness and relevancy of a course and faculty performance were significantly higher for redesigned courses (p < 0.0001) and evaluations were significantly improved for both groups after faculty training was formalised in 2009 (p < 0.001). In summary, educational redesign incorporating serial needs assessment, problem-based learning, and faculty training initiatives were associated with improvement in participant evaluation, but these changes required 4-5 years to become evident.

The level of sense of coherence among Swedish nursing staff.

AIM: To explore the level of sense of coherence among Swedish nursing staff. DESIGN: An explorative quantitative study design was adopted using a short form for measuring sense of coherence. METHODS: Data were collected in January 2018 from nurses working in full-time positions at two hospitals in Western Sweden. A total of 93 nurses completed the 13 item questionnaire measuring sense of coherence. Descriptive statistics were applied to obtain means and standard deviations. Spearman's rank correlation was used to describe strength of association between sense of coherence and socio-demographic categories. Between-group differences were defined using the nonparametric tests of Mann Whitney U test and Kruskal-Wallis test. RESULTS: The internal consistency of the SOC-13 was low. An inter-item-correlation test indicated that two items decreased the internal consistency of the scale. The level of the three dimensions of sense of coherence varied; manageability was weakest and decreased the total sense of coherence. The meaningfulness dimension was as strongest. CONCLUSION: On a national level, nurses reported weaker sense of coherence (SOC) than the general population, but stronger in an international comparison of nurses. They found their work difficult to manage, but meaningful. IMPACT: On a national level, the nurses reported weaker SOC than the general population, but stronger in an international comparison of nurses. Findings from this study will have an impact on how nurses can manage work related stress in terms of sense of coherence. There will also be an impact on nurses' well-being, which in a long run benefits patients.

Prehospital assessment of suspected stroke and TIA: An observational study.

BACKGROUND: Symptoms related to stroke diverge and may mimic many other conditions. AIMS: To evaluate clinical findings among patients with a clinical suspicion of stroke in a prehospital setting and find independent predictors of a final diagnosis of stroke or transient ischemic attack (TIA). METHODS: An observational multicenter study includes nine emergency hospitals in western Sweden. All patients transported to hospital by ambulance and in whom a suspicion of stroke was raised by the emergency medical service clinician before hospital admission during a four-month period were included. RESULTS: Of 1081 patients, a diagnosis of stroke was confirmed at hospital in 680 patients (63%), while 69 (6%) were diagnosed as TIA and 332 patients (31%) received other final diagnoses. In a multiple logistic regression analysis, factors independently associated with a final diagnosis of stroke or TIA were increasing age, odds ratio (OR) per year: 1.02, P = 0.007, a history of myocardial infarction (OR: 1.77, P = 0.01), facial droop (OR: 2.81, P < 0.0001), arm weakness (OR: 2.61, P < 0.0001), speech disturbance (OR: 1.92, P < 0.0001), and high systolic blood pressure (OR: 1.50, P = 0.02), while low oxygen saturation was significantly associated with other diagnoses (OR: 0.41, P = 0.007). More than half of all patients among patients with both stroke/TIA and other final diagnoses died during the five-year follow-up. CONCLUSIONS: Seven factors including the three symptoms included in the Face Arm Speech Test were significantly associated with a final diagnosis of stroke or TIA in a prehospital assessment of patients with a suspected stroke.

Cost-effectiveness of an integrated 'fast track' rehabilitation service for multi-trauma patients: A non-randomized clinical trial in the Netherlands.

BACKGROUND: Multidisciplinary rehabilitation has been recommended for multi-trauma patients, but there is only low-quality evidence to support its use with these patients. This study examined whether a Supported Fast track multi-Trauma Rehabilitation Service (Fast Track) was cost-effective compared to conventional trauma rehabilitation service (Care As Usual) in patients with multi-trauma from a societal perspective with a one-year follow-up. METHODS: An economic evaluation alongside a prospective, multi-center, non-randomized, controlled clinical study, was conducted in the Netherlands. The primary outcome measure was the Functional Independence Measure (FIM). Generic Quality of Life and Quality Adjusted Life Years (QALYs) of the patients were derived using the Short-form 36 Health Status Questionnaire. Incremental Cost-Effectiveness Ratios (ICERs) were stated in terms of costs per unit of FIM improvement and costs per QALY. To investigate the uncertainty around the ICERs, non-parametric bootstrapping was used. RESULTS: In total, 132 patients participated, 65 Fast Track patients and 67 Care As Usual patients. Mean total costs per person were €18,918 higher in the Fast Track group than in the Care As Usual group. Average incremental effects on the FIM were 3.7 points (in favor of the Fast Track group) and the incremental (extra) bootstrapped costs were €19,033, resulting in an ICER for cost per FIM improvement of €5,177. Care As Usual dominated Fast Track in cost per QALY as it gave both higher QALYs and lower costs. All sensitivity analyses attested to the robustness of our results. CONCLUSIONS: This study demonstrated that a multidisciplinary rehabilitation program for multi-trauma patients according to the supported fast track principle is promising but cost-effectiveness evidence remains inconclusive. In terms of functional outcome, Fast Track was more expensive but yielded also more effects compared to the Care As Usual group. Looking at the costs per QALYs, unfavorable ICERs were found. Given the lack of a willingness-to-pay threshold for functional recovery and the relatively short time horizon, it is not possible to draw firm conclusions about the first. TRIAL REGISTRATION: (Current Controlled Trials register: ISRCTN68246661).

A protocol for permissive weight-bearing during allied health therapy in surgically treated fractures of the pelvis and lower extremities.

OBJECTIVE: To optimize rapid clinical recovery and restoration of function and functionality, permissive weight-bearing has been designed as a new aftercare mobilization regimen, within the upper boundary of the therapeutic bandwidth, yet safe enough to avoid overloading. The aim of the present paper is to describe a comprehensive protocol for permissive weight-bearing during allied health therapy and to report on the time to full weight-bearing, as well as the number of complications, in patients with surgically treated fractures of the pelvis and lower extremities undergoing permissive weight-bearing. PATIENTS AND METHODS: This study included surgically treated trauma patients with (peri)- or intra-articular fractures of the pelvis and lower extremities. A standardized permissive weight-bearing protocol was used for all patients. Time to full weight-bearing and number of complications were recorded. RESULTS: This study included 150 patients, 69% male, with a median age of 48 years (interquartile range (IQR) 33.0, 57.0). The median time to full weight bearing was 12.0 weeks (IQR 6.8, 19.2). The complication rate during rehabilitation was 10%. CONCLUSION: The permissive weight-bearing protocol, as described, might be beneficial and has potential to be implemented in trauma patients with surgically treated (peri)- or intra-articular fractures of the pelvis and lower extremities.

Beware of the force of the horse: mechanisms and severity of equestrian-related injuries.

BACKGROUND: Equestrian-related injuries (ERIs) are relatively severe compared with injuries in other popular sports. Previous studies on epidemiology of ERIs vary widely and mainly focus on incidence instead of severity of the injury. PURPOSE: The aim of this study was to determine incidence, mechanisms and severity of ERIs in two Dutch hospitals (level 1 and level 2 trauma centers) over a 5-year period. PATIENTS AND METHODS: All patients with ERIs who visited the emergency departments of VieCuri Medical Centre in Venlo and Maastricht University Medical Centre+ in Maastricht, The Netherlands, between July 2010 and June 2015 were retrospectively included. Clinical data were extracted from medical records. RESULTS: Most ERIs occurred in mounted riders (646 events; 68%); 94.9% of which involved a fall. Being kicked (42.5%) or trapped (30.1%) was the most common cause of injury in unmounted riders. Most frequently injured body parts were the upper extremities (43.8%) in mounted riders and lower extremities (40.5%) in the unmounted group. A relatively high percentage of facial injuries (9.7%) were found in the unmounted group. Seventeen per cent of all ERIs required admission. The median Injury Severity Score was 5 in the admitted population and 1 in the total population. CONCLUSION: Horseback riding is a risky activity. Prior studies particularly studied admitted patients in level 1 trauma centers outside of Europe and demonstrated a high risk of significant injury. However, our study demonstrates that these studies in selected groups might have overestimated the severity of ERIs in the general population.

Patient-reported quality of life and pain after permissive weight bearing in surgically treated trauma patients with tibial plateau fractures: a retrospective cohort study.

INTRODUCTION: A Dutch survey among orthopedic surgeons and trauma surgeons showed that almost 90% of the surgeons do not follow protocols regarding the weight bearing aftercare for tibial plateau fractures. Clinical studies comparing permissive weight bearing (PWB) versus restricted weight bearing (RWB) after surgically treated tibial plateau fractures are not available. The aim of this study was to inventory potential differences in quality of life and pain, and number of complications in patients with surgically treated tibial plateau fractures who followed a PWB regime, relative to those that followed a RWB regime. MATERIALS AND METHODS: This retrospective cohort study included surgically treated trauma patients with tibial plateau fractures, who underwent rehabilitation according to PWB or RWB between 2005 and 2015. Data such as demographics, patient-reported quality of life and pain, and patient outcome were collected. RESULTS: This cohort study included 91 patients with a tibial plateau fracture (31 and 60 patients in the PWB and RWB groups respectively). No significant between-group differences in either age or gender were found. However, a significant difference in fracture type was found between groups, (p = 0.04). No significant differences were found in either patient-reported SF-12 or VAS scores between the PWB group and RWB group. Time to full weight bearing was significantly shorter in the PWB than in the RWB group, i.e., 14.7 versus 20.7 weeks, (p = 0.02). No significant differences were found regarding postoperative complications between the PWB and the RWB groups, i.e., 6.5% versus 10.0%, respectively. CONCLUSION: PWB after surgically treated tibial plateau fractures is safe and is related to a significantly reduced time to full weight bearing with no significant differences in patient-reported quality of life and pain or complication rates.

The role of the Fracture Liaison Service (FLS) in subsequent fracture prevention in the extreme elderly.

BACKGROUND: Several guidelines recommend a bone and fall-related osteoporosis risk assessment in all patients with fracture and age > 50 years. In practice, however, there is no consensus whether screening > 85 years is useful. AIM: To evaluate the subsequent fracture risk in all patient > 85 years, comparing the two populations of Fracture Liaison Service (FLS) attenders and non-attenders. METHODS: All patients > 85 years that presented at the FLS with a non-vertebral fracture were included in the study during a 5-year period (September 2004 and December 2009). Excluded were pathologic fractures, death < 30 days, or patients on osteoporosis treatment. in patients that attended the FLS, assessment of bone mineral density and fall-risk factors were screened. In both the attenders and non-attenders groups, mortality and subsequent fracture rates were scored during a follow-up of 2 years. RESULTS: 282 patients fulfilled inclusion criteria for screening, of which 160 (57%) patients did not attend the FLS. 122 patients were screened for osteoporosis and fall-related risk of whom 72 were diagnosed with osteoporosis. Subsequent fracture risk in both groups was 19%. Medical treatment was started in 51 patients, of which 15 patients developed a subsequent fracture. Cox-regression analysis indicated a significantly lower mortality rate, but not a diminished subsequent fracture rate in the FLS screened population compared to the non-attenders. CONCLUSION: The advantage of a FLS in reducing subsequent fracture risk in patients > 85 years seems to be limited. In practice a large proportion of these patients are not screened.

Malnutrition and Fracture Healing: Are Specific Deficiencies in Amino Acids Important in Nonunion Development?

With the increasing incidence of fractures now, and in the future, the absolute number of bone-healing complications such as nonunion development will also increase. Next to fracture-dependent factors such as large bone loss volumes and inadequate stabilization, the nutritional state of these patients is a major influential factor for the fracture repair process. In this review, we will focus on the influence of protein/amino acid malnutrition and its influence on fracture healing. Mainly, the arginine-citrulline-nitric oxide metabolism is of importance since it can affect fracture healing via several precursors of collagen formation, and through nitric oxide synthases it has influences on the bio-molecular inflammatory responses and the local capillary growth and circulation.

Intercellular communication via gap junction channels between chondrocytes and bone cells.

Cell-to-cell communication between bone, cartilage and the synovial membrane is not fully understood and it is only attributed to the diffusion of substances through the extracellular space or synovial fluid. In this study, we found for the first time that primary bone cells (BCs) including osteocytes, synovial cells (SCs) and chondrocytes (CHs) are able to establish cellular contacts and to couple through gap junction (GJ) channels with connexin43 (Cx43) being dominant. Transwell co-culture and identification by mass spectrometry revealed the exchange of essential amino acids, peptides and proteins including calnexin, calreticulin or CD44 antigen between contacting SCs, BCs and CHs. These results reveal that CHs, SCs and BCs are able to establish intercellular connections and to communicate through GJ channels, which provide a selective signalling route by the direct exchange of potent signalling molecules and metabolites.

Prehospital identification of factors associated with death during one-year follow-up after acute stroke.

OBJECTIVES: In acute stroke, the risk of death and neurological sequelae are obvious threats. The aim of the study was to evaluate the association between various clinical factors identified by the emergency medical service (EMS) system before arriving at hospital and the risk of death during the subsequent year among patients with a confirmed stroke. MATERIAL AND METHODS: All patients with a diagnosis of stroke as the primary diagnosis admitted to a hospital in western Sweden (1.6 million inhabitants) during a four-month period were included. There were no exclusion criteria. RESULTS: In all, 1,028 patients with a confirmed diagnosis of stroke who used the EMS were included in the analyses. Among these patients, 360 (35%) died during the following year. Factors that were independently associated with an increased risk of death were as follows: (1) high age, per year OR 1.07; 95% CI 1.05-1.09; (2) a history of heart failure, OR 2.08; 95% CI 1.26-3.42; (3) an oxygen saturation of <90%, OR 8.05; 95% CI 3.33-22.64; and (4) a decreased level of consciousness, OR 2.19; 95% CI 1.61-3.03. CONCLUSIONS: Among patients with a stroke, four factors identified before arrival at hospital were associated with a risk of death during the following year. They were reflected in the patients' age, previous clinical history, respiratory function, and the function of the central nervous system.

Effect of Shallow and Deep SCUBA Dives on Heart Rate Variability.

Prolonged and high pressure diving may lead to various physiological changes including significant alterations of autonomic nervous system (ANS) activity that may be associated with altered physical performance, decompression sickness, or central nervous system oxygen toxicity. Ideally, researchers could elucidate ANS function before, during, and after dives that are most associated with altered function and adverse outcomes. However, we have a limited understanding of the activities of the ANS especially during deeper prolonged SCUBA diving because there has never been a convenient way to collect physiological data during deep dives. This work is one of the first studies which was able to collect electrocardiogram (ECG) data from SCUBA divers at various depths (33, 66, 99, 150, and 200 ftsw; equivalent to 10.05, 20.10, 30.17, 45.72, and 60.96 m of salt water, respectively) breathing different gas mixtures (air, nitrox and trimix). The aim of this study was to shed light on cardiac ANS behavior during dives, including deep dives. With the aid of dry suits, a Holter monitor that could handle the pressure of a 200 ft. dive, and a novel algorithm that can provide a useful assessment of the ANS from the ECG signal, we investigated the effects of SCUBA dives with different time durations, depths and gas mixtures on the ANS. Principal dynamic mode (PDM) analysis of the ECG, which has been shown to provide accurate separation of the sympathetic and parasympathetic dynamics, was employed to assess the difference of ANS behavior between baseline and diving conditions of varying depths and gas mixtures consisting of air, nitrox and trimix. For all depths and gas mixtures, we found consistent dominance in the parasympathetic activity and a concomitant increase of the parasympathetic dynamics with increasing diving duration and depth. For 33 and 66 ft. dives, we consistently found significant decreases in heart rates (HR) and concomitant increases in parasympathetic activities as estimated via the PDM and root mean square of successive differences (RMSSD) for all time intervals (from the first 5 min to the last 30 min) at the bottom depth when compared to the baseline depth at sea level. The sympathetic dynamics did not change with dive duration or gas mixtures, but at the 150 and 200 ft. dives, we found a significant increase in the sympathetic dynamics in addition to the elevated parasympathetic dynamics when compared to baseline The power spectral density (PSD) measures such as the low frequency (LF), high frequency (HF) and its ratio, and approximate entropy (ApEn) indices were not as consistent when compared to PDM-derived parasympathetic dynamics and RMSSD index.