Combustion-related organic species in temporally resolved urban airborne particulate matter

Accurate characterization of the chemical composition of particulate matter (PM) is essential for improved understanding of source attribution and resultant health impacts. To explore this, we conducted ambient monitoring of a suite of 15 combustion-related organic species in temporally resolved PM_2.5 samples during an ongoing animal exposure study in a near source environment in Detroit, MI. All of the 15 species detected were above the method detection limit in 8 h samples. This study focused on two molecular classes: polycyclic aromatic hydrocarbons (PAHs) and hopanes measured in samples. Of the 12 PAHs studied, benzo[b]fluoranthene (169 pg m^?3), benzo[g,h,i]perylene (124 pg m^?3), and benzo[e]pyrene (118 pg m^?3) exhibited the three highest mean concentrations while 17α(H),21β(H)-hopane (189 pg m^?3) and 17α(H),21β(H)-30-norhopane (145 pg m^?3) had the highest mean concentrations of the three hopanes analyzed in samples. Ratios of individual compound concentrations to total compound concentrations (∑15 compounds) showed the greatest daily variation for 17α(H),21β(H)-hopane (11–28%) and 17α(H),21β(H)-30-norhopane (8–20%). Diagnostic PAH concentration ratios ([IP]/[IP + BP] (range 0.30–0.45), [BaP]/[BaP + BeP] (range 0.26–0.44), [BaP]/[BP] (range 0.41–0.82), [Bb]/[Bk] (range 2.07–2.66)) in samples reflected impacts from a mixture of combustion sources consistent with greater prevalence of petroleum combustion source emissions (gasoline, diesel, kerosene, and crude oil) compared to coal or wood combustion emissions impacts at this urban site. Results from this study demonstrate that short-duration sampling for organic speciation provides temporally relevant exposure information.     

Clinical predictors and outcomes of patients with left ventricular thrombus following ST-segment elevation myocardial infarction

We aimed to characterize the independent predictors of LVT following STEMI and the association with outcomes. The clinical predictors of left ventricular thrombus (LVT) formation after ST-segment elevation myocardial infarction (STEMI) are not well-defined in the contemporary era. We performed a retrospective analysis of STEMI patients at Duke from 2000 to 2011 who had a transthoracic echocardiogram within 90 days post-STEMI and compared patients with and without LVT (LVT+ vs. LVT?). Univariate Cox proportional hazards regression models of baseline characteristics were examined and significant variables were used in a multivariable model to assess adjusted relationships with LVT. A multivariable Cox PH survival model with covariate adjustments was used for assessment of LVT and long-term mortality. Of all eligible patients, 1734 patients met inclusion criteria and 4.3 % (N = 74) had a LVT. LVT+ patients tended to have a history of heart failure (HF) and higher initial troponin compared to LVT- patients. After adjustment, higher heart rate, non-white race, HF severity, and presence of left anterior descending artery (LAD) disease were independent predictors of LVT. There was a trend toward an association between LVT and increased all-cause mortality (HR 1.36; 95 % CI 0.84–2.21, P = 0.22), however this was not statistically significant. LVT was seen in over 4 % of this contemporary post-STEMI population. Several baseline characteristics were independently associated with LVT: Heart rate, HF severity, LAD disease, and non-white race. Prospective studies are warranted to determine whether anticoagulation in patients at increased risk for LVT improves outcomes.     

Recovery and outcomes after the acute respiratory distress syndrome (ARDS) in patients and their family caregivers

Outcomes after acute respiratory distress syndrome (ARDS) are similar to those of other survivors of critical illness and largely affect the nerve, muscle, and central nervous system but also include a constellation of varied physical devastations ranging from contractures and frozen joints to tooth loss and cosmesis. Compromised quality of life is related to a spectrum of impairment of physical, social, emotional, and neurocognitive function and to a much lesser extent discrete pulmonary disability. Intensive care unit-acquired weakness (ICUAW) is ubiquitous and includes contributions from both critical illness polyneuropathy and myopathy, and recovery from these lesions may be incomplete at 5 years after ICU discharge. Cognitive impairment in ARDS survivors ranges from 70 to 100 % at hospital discharge, 46 to 80 % at 1 year, and 20 % at 5 years, and mood disorders including depression and post-traumatic stress disorder (PTSD) are also sustained and prevalent. Robust multidisciplinary and longitudinal interventions that improve these outcomes are still uncertain and data in our literature are conflicting. Studies are needed in family members of ARDS survivors to better understand long-term outcomes of the post-ICU family syndrome and to evaluate how it affects patient recovery.     

Erythrocyte compression index is impaired in patients with residual vein obstruction

Defective clot contraction has been postulated to contribute to thrombosis. We aimed to evaluate the association of residual vein obstruction (RVO) with erythrocyte compression within the whole-blood clot. We studied 32 patients with venous thromboembolism (VTE) taking vitamin K antagonists (VKAs) for at least 3 months (median time in therapeutic range 60%), including 12 (37.5%) with RVO, and 32 age- and sex-matched controls. In all study participants we evaluated whole blood clot retraction, expressed as the erythrocyte compression index (ECI), defined as a ratio of mean polyhedrocyte area to mean native erythrocyte area, along with clot area covered by polyhedrocytes, plasma clot permeability (Ks), clot lysis time (CLT), and thrombin generation. In both groups higher ECI, indicating impaired clot contraction, increased with older age, higher body mass index, red blood cell distribution width, and lower platelet count (all p?<?0.05), but not with red blood cell count. In VTE patients ECI was 15.8% higher than in controls (median 63.6 vs. 54.9%, p?=?0.021). Subjects with RVO had 20% higher ECI and 155% lower clot area covered by polyhedrocytes. RVO patients had also prolonged CLT by 41%, but not Ks, and elevated peak thrombin generation by 33%, as compared to those without RVO (all p?<?0.05). This study is the first to show impaired compression of erythrocytes in RVO patients despite VKA anticoagulation. Altered ECI coexisted with hypolysability and increased thrombin generation. ECI might be useful in the diagnostic process of RVO or post-thrombotic syndrome and can help optimize the anticoagulant therapy.