Critical care involves the care of the sickest patients in the hospital. Critically ill patients have usually been through a significant insult to their body (such as trauma, infection, burn) and have developed organ failure and require life-support. Critical Care is the largest theme bringing together clinicians and scientists from diverse backgrounds and includes collaborative research from hospitals throughout north-west London. Investigations range from evaluating biological mechanisms of organ failure through to the development of innovative technologies which allow the short-term and long-term support and recovery of organs.
Many people are exposed to the environment of an Intensive care unit (ICU) either personally or through a family member. It is often a life-changing event and our work aims to reduce this impact facilitating post-ICU recovery.
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Journal articlePatel BV, Tatham KC, Wilson MR, et al., 2015,
The lung has a unique structure consisting of three functionally different compartments (alveolar, interstitial, and vascular) situated in an extreme proximity. Current methods to localize lung leukocytes using bronchoalveolar lavage and/or lung perfusion have significant limitations for determination of location and phenotype of leukocytes. Here we present a novel method using in vivo antibody labelling to enable accurate compartmental localization/quantification and phenotyping of mouse lung leukocytes. Anesthetized C57BL/6 mice received combined in vivo intravenous and intratracheal labelling with fluorophore-conjugated anti-CD45 antibodies, and lung single cell suspensions were analyzed by flow cytometry. The combined in vivo intravenous and intratracheal CD45 labelling enabled robust separation of the alveolar, interstitial, and vascular compartments of the lung. In naive mice, the alveolar compartment consisted predominantly of resident alveolar macrophages. The interstitial compartment, gated by events negative for both intratracheal and intravenous CD45 staining, showed two conventional dendritic cell populations, as well as a Ly6C(lo) monocyte population. Expression levels of MHCII on these interstitial monocytes were much higher than the vascular Ly6C(lo) monocyte populations. In mice exposed to acid-aspiration induced lung injury, this protocol also clearly distinguished the three lung compartments showing the dynamic trafficking of neutrophils and exudative monocytes across the lung compartments during inflammation and resolution. This simple in vivo dual labelling technique substantially increases the accuracy and depth of lung flow cytometric analysis, facilitates a more comprehensive examination of lung leukocyte pools, and enables the investigation of previously poorly defined 'interstitial' leukocyte populations during models of inflammatory lung diseases.
Journal articleWandrag L, Brett SJ, Frost G, et al., 2015,
Journal articleHerrmann IK, Bertazzo S, O'Callaghan D, et al., 2015,
Differentiating sepsis from non-infectious systemic inflammation based on microvesicle-bacteria aggregation, Nanoscale, Vol: 7, Pages: 13511-13520, ISSN: 2040-3364
Sepsis is a severe medical condition and a leading cause of hospital mortality. Prompt diagnosis and early treatment has a significant, positive impact on patient outcome. However, sepsis is not always easy to diagnose, especially in critically ill patients. Here, we present a conceptionally new approach for the rapid diagnostic differentiation of sepsis from non-septic intensive care unit patients. Using advanced microscopy and spectroscopy techniques, we measure infection-specific changes in the activity of nano-sized cell-derived microvesicles to bind bacteria. We report on the use of a point-of-care-compatible microfluidic chip to measure microvesicle-bacteria aggregation and demonstrate rapid (≤1.5 hour) and reliable diagnostic differentiation of bacterial infection from non-infectious inflammation in a double-blind pilot study. Our study demonstrates the potential of microvesicle activities for sepsis diagnosis and introduces microvesicle-bacteria aggregation as a potentially useful parameter for making early clinical management decisions.
Journal articleO'Callaghan DJ, O'Dea KP, Scott AJ, et al., 2015,
Monocyte Tumor Necrosis Factor-α-Converting Enzyme Catalytic Activity and Substrate Shedding in Sepsis and Noninfectious Systemic Inflammation., Critical Care Medicine, Vol: 43, Pages: 1375-1385, ISSN: 1530-0293
OBJECTIVES: To determine the effect of severe sepsis on monocyte tumor necrosis factor-α-converting enzyme baseline and inducible activity profiles. DESIGN: Observational clinical study. SETTING: Mixed surgical/medical teaching hospital ICU. PATIENTS: Sixteen patients with severe sepsis, 15 healthy volunteers, and eight critically ill patients with noninfectious systemic inflammatory response syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Monocyte expression of human leukocyte antigen-D-related peptide, sol-tumor necrosis factor production, tumor necrosis factor-α-converting enzyme expression and catalytic activity, tumor necrosis factor receptor 1 and 2 expression, and shedding at 48-hour intervals from day 0 to day 4, as well as p38-mitogen activated protein kinase expression. Compared with healthy volunteers, both sepsis and systemic inflammatory response syndrome patients' monocytes expressed reduced levels of human leukocyte antigen-D-related peptide and released less sol-tumor necrosis factor on in vitro lipopolysaccharide stimulation, consistent with the term monocyte deactivation. However, patients with sepsis had substantially elevated levels of basal tumor necrosis factor-α-converting enzyme activity that were refractory to lipopolysaccharide stimulation and this was accompanied by similar changes in p38-mitogen activated protein kinase signaling. In patients with systemic inflammatory response syndrome, monocyte basal tumor necrosis factor-α-converting enzyme, and its induction by lipopolysaccharide, appeared similar to healthy controls. Changes in basal tumor necrosis factor-α-converting enzyme activity at day 0 for sepsis patients correlated with Acute Physiology and Chronic Health Evaluation II score and the attenuated tumor necrosis factor-α-converting enzyme response to lipopolysaccharide was associated with increased mortality. Similar changes in monocyte tumor necrosis factor-α-converting enz
Journal articleFletcher ME, Boshier PR, Wakabayashi K, et al., 2015,
Influence of glutathione-S-transferase (GST) inhibition on lung epithelial cell injury: role of oxidative stress and metabolism, AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY, Vol: 308, Pages: L1274-L1285, ISSN: 1040-0605
Oxidant-mediated tissue injury is key to the pathogenesis of acute lung injury. Glutathione-S-transferases (GSTs) are important detoxifying enzymes that catalyze the conjugation of glutathione with toxic oxidant compounds and are associated with acute and chronic inflammatory lung diseases. We hypothesized that attenuation of cellular GST enzymes would augment intracellular oxidative and metabolic stress and induce lung cell injury. Treatment of murine lung epithelial cells with GST inhibitors, ethacrynic acid (EA), and caffeic acid compromised lung epithelial cell viability in a concentration-dependent manner. These inhibitors also potentiated cell injury induced by hydrogen peroxide (H2O2), tert-butyl-hydroperoxide, and hypoxia and reoxygenation (HR). SiRNA-mediated attenuation of GST-π but not GST-μ expression reduced cell viability and significantly enhanced stress (H2O2/HR)-induced injury. GST inhibitors also induced intracellular oxidative stress (measured by dihydrorhodamine 123 and dichlorofluorescein fluorescence), caused alterations in overall intracellular redox status (as evidenced by NAD+/NADH ratios), and increased protein carbonyl formation. Furthermore, the antioxidant N-acetylcysteine completely prevented EA-induced oxidative stress and cytotoxicity. Whereas EA had no effect on mitochondrial energetics, it significantly altered cellular metabolic profile. To explore the physiological impact of these cellular events, we used an ex vivo mouse-isolated perfused lung model. Supplementation of perfusate with EA markedly affected lung mechanics and significantly increased lung permeability. The results of our combined genetic, pharmacological, and metabolic studies on multiple platforms suggest the importance of GST enzymes, specifically GST-π, in the cellular and whole lung response to acute oxidative and metabolic stress. These may have important clinical implications.
Journal articleMoore AC, Stacey MJ, Bailey KG, et al., 2015,
BACKGROUND: Heat illness is a preventable disorder in military populations. Measures that protect vulnerable individuals and contribute to effective Immediate Treatment may reduce the impact of heat illness, but depend upon adequate understanding and awareness among Commanders and their troops. OBJECTIVE: To assess risk factors for heat illness in British soldiers deployed to the hot Collective Training Environment (CTE) and to explore awareness of Immediate Treatment responses. METHODS: An anonymous questionnaire was distributed to British soldiers deployed in the hot CTEs of Kenya and Canada. Responses were analysed to determine the prevalence of individual (Intrinsic) and Command-practice (Extrinsic) risk factors for heat illness and the self-reported awareness of key Immediate Treatment priorities (recognition, first aid and casualty evacuation). RESULTS: The prevalence of Intrinsic risk factors was relatively low in comparison with Extrinsic risk factors. The majority of respondents were aware of key Immediate Treatment responses. The most frequently reported factors in each domain were increased risk by body composition scoring, inadequate time for heat acclimatisation and insufficient briefing about casualty evacuation. CONCLUSIONS: Novel data on the distribution and scale of risk factors for heat illness are presented. A collective approach to risk reduction by the accumulation of 'marginal gains' is proposed for the UK military. This should focus on limiting Intrinsic risk factors before deployment, reducing Extrinsic factors during training and promoting timely Immediate Treatment responses within the hot CTE.
Journal articleHernandez-Silveira M, Ahmed K, Ang SS, et al., 2015,
Assessment of the feasibility of an ultra-low power, wireless digital patch for the continuous ambulatory monitoring of vital signs., BMJ Open, Vol: 5, Pages: e006606-e006606, ISSN: 2044-6055
BACKGROUND AND OBJECTIVES: Vital signs are usually recorded at 4-8 h intervals in hospital patients, and deterioration between measurements can have serious consequences. The primary study objective was to assess agreement between a new ultra-low power, wireless and wearable surveillance system for continuous ambulatory monitoring of vital signs and a widely used clinical vital signs monitor. The secondary objective was to examine the system's ability to automatically identify and reject invalid physiological data. SETTING: Single hospital centre. PARTICIPANTS: Heart and respiratory rate were recorded over 2 h in 20 patients undergoing elective surgery and a second group of 41 patients with comorbid conditions, in the general ward. OUTCOME MEASURES: Primary outcome measures were limits of agreement and bias. The secondary outcome measure was proportion of data rejected. RESULTS: The digital patch provided reliable heart rate values in the majority of patients (about 80%) with normal sinus rhythm, and in the presence of abnormal ECG recordings (excluding aperiodic arrhythmias such as atrial fibrillation). The mean difference between systems was less than ±1 bpm in all patient groups studied. Although respiratory data were more frequently rejected as invalid because of the high sensitivity of impedance pneumography to motion artefacts, valid rates were reported for 50% of recordings with a mean difference of less than ±1 brpm compared with the bedside monitor. Correlation between systems was statistically significant (p<0.0001) for heart and respiratory rate, apart from respiratory rate in patients with atrial fibrillation (p=0.02). CONCLUSIONS: Overall agreement between digital patch and clinical monitor was satisfactory, as was the efficacy of the system for automatic rejection of invalid data. Wireless monitoring technologies, such as the one tested, may offer clinical value when implemented as part of wider hospital systems that integrate and supp
Journal articleWoods SJ, Waite AAC, O'Dea KP, et al., 2015,
Journal articlePetrie J, Easton S, Naik V, et al., 2015,
Journal articleRautanen A, Mills TC, Gordon AC, et al., 2015,
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