3,432 research outputs found
Torsional Stiffness of a Race Car
Torsional stiffness plays a major role in any road vehicle. To understand torsional stiffness of a vehicle and make future iterations and improvements, a proper torsional stiffness jig is required to prove accurate and useful data. This report encompasses the new and improved testing jig and potential improvement ideas for more accurate results. With real data result relating to FEA calculations, designers can be confident in the FEA changes to torsional stiffness is accurate and will yield the probably results they desired. This report shows the methodology, manufacturing process and testing procedure to use on any Baja or SAE vehicle in years to come
Care of victims of suicide bombing
history of suicide bombingSuicide bombers often target crowds. This commentary discusses the additional features required in a medical response beyond conventional mass casualty care, including forensic documentation, preservation of evidence, suspect tissue identification and viral status, victim counselling and postexposure prophylaxis. We propose a pathway for care of victims of a suicide bomb, adapting elements from protocols for child abuse, sexual assault and needle-stick exposure
Helicobacter pylori -Pulsed Dendritic Cells Induce H. pylori -Specific Immunity in Mice
Background: The growing concern over the emergence of antibiotic-resistant Helicobacter pylori infection is propelling the development of an efficacious vaccine to control this highly adaptive organism. Aim: We studied the use of a dendritic cell (DC)-based vaccine against H. pylori infection in mice. Methods: The cellular immune responses to murine bone marrow-derived DCs pulsed with phosphate-buffered saline (PBS-DC) or live H. pylori SS1 (HP-DC) were assessed in vitro and in vivo. The protective immunity against H. pylori SS1 oral challenge was compared between HP-DC or PBS-DC immunized mice. The effect of regulatory T-cell (Treg) depletion by anti-CD25 antibody on HP-DC vaccine efficacy was also evaluated. Results: HP-DC induced a Th1-dominant response in vitro. In vivo, HP-DC immunized mice were characterized by a mixed Th1/Th2 peripheral immune response. However, in the stomach, HP-DC immunized mice expressed a higher level of IFN-γ compared to PBS-DC immunized mice; no difference was found for interleukin-5 expressions in the stomach. A lower bacterial colonization post- H. pylori challenge was observed in HP-DC immunized mice compared to PBS-DC immunized mice with no significant difference in gastritis severity. H. pylori -specific Th1 response and protective immunity were further enhanced in vivo by depletion of Treg with anti-CD25 antibody. Conclusion: DC-based anti- H. pylori vaccine induced H. pylori -specific helper T-cell responses capable of limiting bacterial colonization. Our data support the critical role of effector cellular immune response in the development of H. pylori vaccine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75711/1/j.1523-5378.2008.00606.x.pd
Epidemics on dynamic networks
In many populations, the patterns of potentially infectious contacts are transients that can be described as a network with dynamic links. The relative timescales of link and contagion dynamics and the characteristics that drive their tempos can lead to important differences to the static case. Here, we propose some essential nomenclature for their analysis, and then review the relevant literature. We describe recent advances in they apply to infection processes, considering all of the methods used to record, measure and analyse them, and their implications for disease transmission. Finally, we outline some key challenges and opportunities in the field. Keywords: Social network analysis, Disease models, Network metrics, Network dat
Reduction in IL-33 expression exaggerates ischaemia/reperfusion-induced myocardial injury in mice with diabetes mellitus
Aims: The underlying mechanism(s) of vulnerability of the diabetic myocardium to ischaemia/reperfusion (I/R)-induced injury is not fully understood. Interleukin-33 (IL-33) has been reported showing the beneficial effect to the myocardium on I/R injury. The aims of this study were to test whether diabetes mellitus (DM) affects myocardial levels of IL-33 and to examine whether reduction in IL-33 is responsible for exaggerated I/R injury in the diabetic myocardium.
Methods and results: DM hearts were challenged with I/R in vivo, whereas while isolated cardiomyocytes in vitro were conditioned with high glucose (HG) followed by an anoxia/reoxygenation (A/R) challenge. Myocardial levels of IL-33 were decreased in mice with DM which was associated with increased protein kinase C βII (PKCβII) activation. Exogenous IL-33 prevented the DM-induced PKCβII activation and attenuated I/R injuries (myocardial infarction size and apoptosis). HG-conditioned myocytes incurred exaggerated apoptosis when compared with naïve myocytes after A/R which was attenuated by IL-33. HG activated PKCβII in cardiomyocytes, which was further enhanced by A/R. IL-33 prevented the PKCβII activation in myocytes with HG or HG and A/R. Inhibition of PKCβII prevented the beneficial effect of IL-33. Finally, IL-33 up-regulated diacylglycerol kinase zeta (DGK-zeta) in cardiomyocytes and reversed the down-regulation of myocardial DGK-zeta in mice with DM.
Conclusion: Our results indicate that decreased levels of IL-33 are responsible for the increased sensitivity of the myocardium to I/R in DM. Reduction in IL-33 results in a chronic activation of PKCβII. I/R further enhances PKCβII activation in the diabetic myocardium which results in exaggeration of myocardial injury
Utilization profile of the trauma intensive care unit at the Role 3 Multinational Medical Unit at Kandahar Airfield between May 1 and Oct. 15, 2009
Background: In the war against the Taliban, Canada was the lead North Atlantic Treaty Organization (NATO) nation to provide medical and surgical care to NATO soldiers, Afghanistan National Army soldiers, Afghanistan Nation Police, civilians working in and outside Kandahar Airfield and Afghanistan civilians at the Role 3 Multinational Medical Unit (R3MMU) from February 2006 to October 2009. Methods: We obtained data from the Joint Theatre Trauma Registry between May 1 and Oct. 15, 2009; 188 patients were admitted to the R3MMU intensive care unit (ICU). We analyzed the ICU data according to types and causes of trauma, mechanical ventilation prevalence, ICU medical and surgical complications, blood products utilization, length of stay in the ICU and mortality. Results: The admitting services were general surgery (35%), neurosurgery (29%), orthopedic surgery (18%) and internal medicine (3%). Improvised explosive devices (46%) and gunshot wounds (26%) were the main causes of ICU admissions. The mean injury severity score for all patients admitted to the ICU was 37, and 81% of ICU patients required mechanical ventilation for a mean duration of 3 days. The main ICU complications were coagulopathy (6.4%), aspiration pneumonia (4.3%), pneumothorax (3.7%) and wound infection (2.7%). The following blood products were most used: packed red blood cells (55%), fresh frozen plasma (54%), platelets (29%) and cryoprecipitate (23%). The average length of stay in the ICU was 4.3 days, and the survival rate was 93%. Conclusion: The high survival rate suggests that ICU care is a necessary and vital resource for a trauma hospital in a war zone
Cardiac Fibroblasts Contribute to Myocardial Dysfunction in Mice with Sepsis: The Role of NLRP3 Inflammasome Activation
Myocardial contractile dysfunction in sepsis is associated with the increased morbidity and mortality. Although the underlying mechanisms of the cardiac depression have not been fully elucidated, an exaggerated inflammatory response is believed to be responsible. Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome is an intracellular platform that is involved in the maturation and release of interleukin (IL)-1 beta. The aim of the present study is to evaluate whether sepsis activates NLRP3 inflammasome/caspase-1/IL-1 beta pathway in cardiac fibroblasts (CFs) and whether this cytokine can subsequently impact the function of cardiomyocytes (cardiac fibroblast-myocyte crosstalk). We show that treatment of CFs with lipopolysaccharide (LPS) induces upregulation of NLRP3, activation of caspase-1, as well as the maturation (activation) and release of IL-1 beta. In addition, the genetic (small interfering ribonucleic acid [siRNA]) and pharmacological (glyburide) inhibition of the NLRP3 inflammasome in CFs can block this signaling pathway. Furthermore, the inhibition of the NLRP3 inflammasome in cardiac fibroblasts ameliorated the ability of LPS-chalenged CFs to impact cardiomyocyte function as assessed by intracellular cyclic adenosine monophosphate (cAMP) responses in cardiomyocytes. Salient features of this the NLP3 inflammasome/ caspase-1 pathway were confirmed in in vivo models of endotoxemia/sepsis. We found that inhibition of the NLRP3 inflammasome attenuated myocardial dysfunction in mice with LPS and increased the survival rate in mice with feces-induced peritonitis. Our results indicate that the activation of the NLRP3 inflammasome in cardiac fibroblasts is pivotal in the induction of myocardial dysfunction in sepsis
Erythropoietin improves skeletal muscle microcirculation and tissue bioenergetics in a mouse sepsis model
Introduction: The relationship between oxygen delivery and consumption in sepsis is impaired, suggesting a microcirculatory perfusion defect. Recombinant human erythropoietin (rHuEPO) regulates erythropoiesis and also exerts complex actions promoting the maintenance of homeostasis of the organism under stress. The objective of this study was to test the hypothesis that rHuEPO could improve skeletal muscle capillary perfusion and tissue oxygenation in sepsis.
Methods: Septic mice in three experiments received rHu-EPO 400 U/kg subcutaneously 18 hours after cecal ligation and perforation (CLP). The first experiment measured the acute effects of rHuEPO on hemodynamics, blood counts, and arterial lactate level. The next two sets of experiments used intravital microscopy to observe capillary perfusion and nicotinamide adenine dinucleotide (NADH) fluorescence post-CLP after treatment with rHuEPO every 10 minutes for 40 minutes and at 6 hours. Perfused capillary density during a three-minute observation period and NADH fluorescence were measured.
Results: rHuEPO did not have any effects on blood pressure, lactate level, or blood cell numbers. CLP mice demonstrated a 22% decrease in perfused capillary density compared to the sham group (28.5 versus 36.6 capillaries per millimeter; p \u3c 0.001). Treatment of CLP mice with rHuEPO resulted in an immediate and significant increase in perfused capillaries in the CLP group at all time points compared to baseline from 28.5 to 33.6 capillaries per millimeter at 40 minutes; p \u3c 0.001. A significant increase in baseline NADH, suggesting tissue hypoxia, was noted in the CLP mice compared to the sham group (48.3 versus 43.9 fluorescence units [FU]; p = 0.03) and improved with rHuEPO from 48.3 to 44.4 FU at 40 minutes (p = 0.02). Six hours after treatment with rHuEPO, CLP mice demonstrated a higher mean perfused capillary density (39.4 versus 31.7 capillaries per millimeter; p \u3c 0.001) and a lower mean NADH fluorescence as compared to CLP+normal saline mice (49.4 versus 52.7 FU; p = 0.03).
Conclusion: rHuEPO produced an immediate increase in capillary perfusion and decrease in NADH fluorescence in skeletal muscle. Thus, it appears that rHuEPO improves tissue bioenergetics, which is sustained for at least six hours in this murine sepsis model
The Role 3 Multinational Medical Unit at Kandahar Airfield 2005–2010
In late 2005, Canadian Forces Health Services (CFHS) was tasked with the command of the NATO Role 3 Multinational Medical Unit (R3MMU) on Kandahar Airfield in southern Afghanistan. Preparations drew on past experience and planning. Eight complete hospital contingents were trained and deployed in rotation. Near-reality simulation training was undertaken with the combat brigade, including complete deployment of the field hospital in the exercise area. Standard operating procedures (SOP) were developed and applied by each rotation so successfully that they were adopted by the new command in late 2009. The Canadian period at R3MMU had the highest survival rate ever recorded for victims of war. Lessons learned are being applied among victims of the conflict and trauma. The experience of the R3MMU was used to successfully deploy a hospital as part of the earthquake relief effort in Haiti in 2010. The training protocols and SOP are being applied to disaster preparedness in Canadian civilian hospitals
Utilization profile of the Canadian-led coalition Role 2 Medical Treatment Facility in Iraq: the growing requirement for multinational interoperability.
Background: The Canadian Armed Forces deployed a Role 2 Medical Treatment Facility (R2MTF) to Iraq in November 2016 as part of Operation IMPACT. We compared the multinational interoperability required of this R2MTF with that of similar facilities previously deployed by Canada or other nations.
Methods: We reviewed data (Nov. 4, 2016, to Oct. 3, 2017) from the electronic Disease and Injury Surveillance Report and the Daily Medical Situation Report. Clinical activity was stratified by Global Burden of Diseases category, ICD-10 code, mechanism of injury, services used, encounter type, nationality and blood product usage. We reviewed the literature to identify utilization profiles for other MTFs over the last 20 years.
Results: In total, 1487 patients were assessed. Of these, 5.0% had battle injuries requiring damage-control resuscitation and/or damage-control surgery, with 55 casualties requiring medical evacuation after stabilization. Trauma and disease non-battle injuries accounted for 44% and 51% of patient encounters, respectively. Other than dental conditions, musculoskeletal disorders accounted for most presentations. Fifty-seven units of fresh frozen plasma and 64 units of packed red blood cells were used, and the walking blood bank was activated 7 times. Mass casualty activations involved coordination of health care and logistical resources from more than 12 countries. In addition to host nation military and civilian casualties, patients from 15 different countries were treated with similar frequency.
Conclusion: The experience of the Canadian R2MTF in Iraq demonstrates the importance of multinational interoperability in providing cohesive medical care in coalition surgical facilities. Multinational interoperability derives from a unique relationship between higher medical command collaboration, international training and adherence to common standards for equipment and clinical practice
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