The flax genome reveals orbitide diversity.

BACKGROUND: Ribosomally-synthesized cyclic peptides are widely found in plants and exhibit useful bioactivities for humans. The identification of cyclic peptide sequences and their precursor proteins is facilitated by the growing number of sequenced genomes. While previous research largely focused on the chemical diversity of these peptides across various species, there is little attention to a broader range of potential peptides that are not chemically identified. RESULTS: A pioneering study was initiated to explore the genetic diversity of linusorbs, a group of cyclic peptides uniquely occurring in cultivated flax (Linum usitatissimum). Phylogenetic analysis clustered the 5 known linusorb precursor proteins into two clades and one singleton. Preliminary tBLASTn search of the published flax genome using the whole protein sequence as query could only retrieve its homologues within the same clade. This limitation was overcome using a profile-based mining strategy. After genome reannotation, a hidden Markov Model (HMM)-based approach identified 58 repeats homologous to the linusorb-embedded repeats in 8 novel proteins, implying that they share common ancestry with the linusorb-embedded repeats. Subsequently, we developed a customized profile composed of a random linusorb-like domain (LLD) flanked by 5 conserved sites and used it for string search of the proteome, which extracted 281 LLD-containing repeats (LLDRs) in 25 proteins. Comparative analysis of different repeat categories suggested that the 5 conserved flanking sites among the non-homologous repeats have undergone convergent evolution driven by functional selection. CONCLUSIONS: The profile-based mining approach is suitable for analyzing repetitive sequences. The 25 LLDR proteins identified herein represent the potential diversity of cyclic peptides within the flax genome and lay a foundation for further studies on the functions and evolution of these protein tandem repeats.

Rationale and design of the safe and timely antithrombotic removal - ticagrelor (STAR-T) trial: A prospective, multi-center, double-blind, randomized controlled trial evaluating reductions in postoperative bleeding with intraoperative removal of ticagrelor by the drugsorb™-ATR device in patients undergoing cardiothoracic surgery within 48 hours from last ticagrelor dose.

BACKGROUND: Ticagrelor is often administered to patients with acute coronary syndromes. However, when these patients require urgent or emergent cardiothoracic (CT) surgery the presence of ticagrelor significantly increases surgical bleeding. The goal of the current trial is to evaluate the effectiveness and safety of the DrugSorb-ATR hemoadsorption device for the intraoperative removal of ticagrelor to reduce postoperative bleeding in the above patient population. The Safe and Timely Antithrombotic Removal - Ticagrelor (STAR-T) Trial is a multi-center, double-blind, randomized, controlled trial enrolling patients who require cardiothoracic surgery on cardiopulmonary bypass (CPB) within 48 hours of last ticagrelor dose. METHODS: Subjects will be randomized 1:1 to receive either the DrugSorb-ATR device or an identical sham device during CPB. The study will enroll up to 120 subjects at 20 U.S centers, and the primary outcome is the composite of fatal perioperative bleeding, moderate/severe/massive bleeding according to the Universal Definition of Perioperative Bleeding in Cardiac Surgery (UDPB), and 24 hours chest tube drainage. The components of the composite are hierarchically ranked according to clinical significance and the primary analysis will utilize the Win Ratio method. Percent change in ticagrelor levels before and after CPB (drug removal) will be the key secondary endpoint. An independent Clinical Events Committee will adjudicate all clinical endpoints including safety endpoints relating to postoperative thrombotic events. Subjects will be followed through 30 days after the index operation. CONCLUSIONS: The results from STAR-T, if positive, will potentially support FDA market approval for DrugSorb-ATR, and provide a solution to an important unmet clinical need.

Pharmacokinetic and pharmacodynamic profiles of a novel phospholipid-aspirin complex liquid formulation and low dose enteric-coated aspirin: results from a prospective, randomized, crossover study.

Low dose enteric-coated aspirin (EC-ASA) is routinely used for secondary cardiovascular event prevention. However, absorption of EC tablets is poor, which can result in subtherapeutic antiplatelet effects. Phospholipid-aspirin liquid filled capsules (PL-ASA) are a novel FDA-approved immediate-release formulation designed to reduce gastrointestinal (GI) injury by limiting direct contact with the stomach lining. We compared the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of PL-ASA versus EC-ASA at a low dose. This randomized, open-label, crossover study assessed PK and PD following a single 81-mg dose of PL-ASA versus EC-ASA under fasting conditions in 36 volunteers without cardiovascular disease between 18 and 75 years of age. Volunteers were randomly assigned 1:1 to either PL-ASA then EC-ASA or vice versa with a minimum 14-day washout. Assessments included PK parameters for acetylsalicylic acid and salicylic acid, platelet aggregation in response to arachidonic acid (AA), and serum thromboxane B2 (TxB2) assessments over 24 h. PL-ASA was rapidly absorbed. PL-ASA reached Tmax 3 h earlier (1.01 vs. 4.00 h, p < 0.0001), with almost double the Cmax (720 vs. 368 ng/mL, p < 0.0001) and overall 44% higher exposure of acetylsalicylic acid (AUC0-t: 601 vs. 416 h*ng/mL, p = 0.0013) compared with EC-ASA. Within 1 h of dosing, PL-ASA achieved significantly lower residual platelet aggregation, which persisted for the full 24 h (median AA-LTA was 47% with PL-ASA vs. 80.5% with EC-ASA; p = 0.0022 at hour-24). Treatment with PL-ASA also resulted in significantly lower serum TxB2 concentrations at each time point compared with EC-ASA (all p-values < 0.05). PL-ASA resulted in faster and more complete aspirin absorption paralleled by more prompt and potent platelet inhibition compared with EC-ASA after a single 81 mg dose. PL-ASA represents an attractive novel aspirin formulation for the secondary prevention of cardiovascular events.Clinical Trial Registration ClinicalTrials.gov identifier: NCT04811625.

Influence of Lipid Excipients on Platelet Function and the Pharmacodynamic Effects of Aspirin.

ABSTRACT: The combination of pharmaceutical lipid excipients with aspirin in a novel liquid oral formulation (Vazalore) limits gastrointestinal toxicity of aspirin. This study was performed to determine whether the lipid excipients influence the pharmacodynamic effects of aspirin and whether the excipients directly affect platelet function. The pharmacodynamic effects of aspirin were assessed over a range of concentrations designed to exert limited to maximal inhibition of cyclooxygenase-1 (COX1) necessary for thromboxane A2 production. Platelet aggregation induced by arachidonic acid and assessed with the use of light transmission aggregometry was used as a direct measure of the inhibition of COX1 by aspirin. Flow cytometry was used to assess the direct effect of excipients on platelet function. Twice the ratio of lipid excipient to aspirin used in the formulation of the novel oral agent was used. Blood was taken from 20 healthy subjects and anticoagulated with trisodium citrate (3.2%, 1:10 vol/vol). Aspirin and excipients were added in vitro and incubated for 10 minutes before performance of light transmission aggregometry and flow cytometry. The excipients did not limit the pharmacodynamic effects of aspirin. When the extent of inhibition of platelet aggregation was limited, the excipients tended to enhance pharmacodynamic effects. The excipients did not activate platelets in the absence of agonist and did not alter activation of platelets in response to adenosine diphosphate, arachidonic acid, thrombin, or convulxin (a collagen mimetic). Lipid excipients used in an oral formulation of aspirin do not impair the pharmacodynamic effects of aspirin and do not alter platelet function.

Variation in platelet expression of FcγRIIa after myocardial infarction.

FcγRIIa amplifies platelet activation and greater platelet expression of FcγRIIa identifies patients at greater risk of subsequent cardiovascular events. Thus, platelet expression of FcγRIIa may be useful to guide therapy. Because platelet function tests are impacted by preparative procedures and substantial intra-individual variability, we examined the impact of these factors on platelet expression of FcγRIIa in blood from healthy subjects and in patients after myocardial infarction (MI). Platelet expression of FcγRIIa was quantified with the use of flow cytometry. Blood was taken from healthy subjects and 114 patients after a MI in whom platelet expression of FcγRIIa was quantified before discharge and at 6 ± 1 months. Neither anticoagulants nor the antiplatelet agent cangrelor changed platelet expression of FcγRIIa. Intra-individual variation in platelet FcγRIIa expression was 8.5% ± 5% over the course of 1 month in healthy subjects. Platelet FcγRIIa expression was within 20% of the baseline value after 6 months in 71% of patients after MI. In summary, because FcγRIIa is a protein on the surface of platelets, assay conditions and antiplatelet agents do not change expression. Intra-individual variability in platelet expression of FcγRIIa is modest. Accordingly, platelet expression of FcγRIIa is a marker of increased platelet reactivity that can be reliably and repeatedly measured.Clinical Trial Registration: NCT02505217.

Surveillance and Management of Troponin Elevation after Vascular Surgery.

BACKGROUND: Postopertive troponin elevation may occur without typical or atypical cardiac symptoms and is associated with an increased 30-day morbidity and mortality. The objective of the study was to implement a quality improvement initiative of postoperative troponin surveillance algorithm aimed at intensifying medical management after vascular surgery. METHODS: We conducted a single-center study of postoperative troponin surveillance after vascular surgery (n = 201) at a tertiary care, academic medical center from January to December 2016. Troponin surveillance was performed on postoperative days 1-3 after carotid endarterectomy, endovascular aortic repair, infrainguinal bypass, open abdominal aortic aneurysm repair, peripheral vascular intervention, and suprainguinal bypass, regardless of cardiac symptoms. Patients with troponin I elevation (>0.034 ng/mL) were managed with a treatment algorithm which included single or dual antiplatelet (AP) agent, high-intensity statin therapy, smoking cessation consultation, and outpatient cardiology consultation and stress testing. Patients with troponin elevation ≥1.0 ng/mL received inpatient cardiology consultation. We assessed adherence to the protocol for intensification of best medical therapy defined as high-dose statin therapy, increase in AP therapy, and smoking cessation consultation according to the established algorithm. RESULTS: Troponin elevation was recorded in 17% (34/201) of patients and was associated with cardiac symptoms in 8 patients (24%), while 26 (76%) patients had an asymptomatic abnormal troponin on postoperative surveillance. One patient was excluded due to death immediately after SUPRA, resulting in 200 patients. Troponin elevation ≥1.0 ng/mL occurred in 11 asymptomatic patients (5.5%). Any intensification of medical therapy was instituted in 76% of patients with elevated troponin and included high-intensity statin therapy (58%), increase in AP therapy (18%), and smoking cessation consultation (66%). Once an elevated troponin level was recognized, 52% of our patients received cardiology consultation with an increased likelihood (100%) in patients with troponin ≥1 ng/mL (P < 0.001). Adherence to outpatient stress testing was 66%. Intensification of medical therapy was not significantly different between patients with abnormal troponin values, >0.034-1.0 (n = 23) versus ≥1.0 ng/mL (n = 10); statin therapy (P = 1.0), AP (P = 0.34), and smoking cessation (P = 1.0). One-year mortality was higher in patients with postoperative troponin elevation than those with normal postoperative troponin levels (12% vs. 2.4%; P = 0.03). CONCLUSIONS: Routine postoperative troponin surveillance results in intensification of statin therapy in patients with asymptomatic troponin elevation. Further study is needed to determine if this approach reduces long-term cardiovascular morbidity and mortality.

International Expert Consensus on Switching Platelet P2Y12 Receptor-Inhibiting Therapies.

Dual antiplatelet therapy with aspirin and a P2Y12 inhibitor is the treatment of choice for the prevention of atherothrombotic events in patients with acute coronary syndromes and for those undergoing percutaneous coronary interventions. The availability of different oral P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) has enabled physicians to contemplate switching among therapies because of specific clinical scenarios. The recent introduction of an intravenous P2Y12 inhibitor (cangrelor) further adds to the multitude of modalities and settings in which switching therapies may occur. In clinical practice, it is not uncommon to switch P2Y12 inhibitor, and switching may be attributed to a variety of factors. However, concerns about the safety of switching between these agents have emerged. Practice guidelines have not fully elaborated on how to switch therapies, leaving clinicians with limited guidance on when and how to switch therapies when needed. This prompted the development of this expert consensus document by key leaders from North America and Europe with expertise in basic, translational, and clinical sciences in the field of antiplatelet therapy. This expert consensus provides an overview of the pharmacology of P2Y12 inhibitors, different modalities and definitions of switching, and available literature and recommendations for switching between P2Y12 inhibitors.

Underutilization of antiplatelet and statin therapy after postoperative myocardial infarction following vascular surgery.

OBJECTIVE: The objective of this study was to investigate adherence to practice guidelines for antiplatelet and statin use after postoperative myocardial infarction (POMI) and its effect on late mortality following vascular surgery in a multicenter registry. METHODS: Antiplatelet and statin use was examined in 1749 vascular surgery procedures with POMI within the Vascular Quality Initiative (VQI) from 2005 to 2015. Our primary aim was to assess cardiac medication (CM) use at discharge, defined as (1) single antiplatelet therapy (SAPT; aspirin or P2Y12 inhibitor) or dual antiplatelet therapy (DAPT; aspirin and P2Y12 inhibitor) and (2) statin therapy. Long-term mortality in patients with POMI was analyzed on the basis of discharge CM. A proportional hazards model was developed to control for factors associated with mortality. Regional differences in CM use at discharge after POMI were compared. RESULTS: Overall discharge CM use after POMI included aspirin (81%), P2Y12 inhibitor (38%), statin therapy (76%), and combined antiplatelet and statin (74%). At discharge, 26% of patients were not receiving combined antiplatelet and statin therapy. SAPT (50%) was more common than DAPT (35%; P < .001). Patients with POMI undergoing carotid endarterectomy were more likely to be discharged on CM (80%) compared with patients undergoing infrainguinal bypass (78%), suprainguinal bypass (72%), endovascular aneurysm repair (71%), and open abdominal aortic aneurysm repair (59%; P < .001). Patients receiving SAPT or DAPT plus statin therapy had improved survival (79%) compared with those receiving noncombination or no therapy (69%) with mean follow-up of 5.5 years and 4.9 years, respectively (log-rank, P = .001). After adjustment for covariates including preoperative medications, treatment with SAPT or DAPT plus statin at discharge was associated with lower late mortality compared with noncombination or no therapy (hazard ratio, 0.72; 95% confidence interval, 0.56-0.93; P = .01). Regional variation in CM at discharge following POMI was also observed with a range of 33% to 100% (P = .05). CONCLUSIONS: Within the VQI, regional and procedure-specific variation exists in CM regimen after POMI following vascular surgery. Absence of combined antiplatelet and statin therapy at discharge after POMI was associated with higher late mortality and represents an area for quality improvement in the care of these patients.

A comparison of extraction systems for plant water stable isotope analysis.

RATIONALE: The stable isotope ratios of water (δ2 H and δ18 O values) have been widely used to trace water in plants in a variety of physiological, ecohydrological, biogeochemical and hydrological studies. In such work, the analyte must first be extracted from samples, prior to isotopic analysis. While cryogenic vacuum distillation is currently the most widely used method reported in the literature, a variety of extraction-collection-analysis methods exist. A formal inter-method comparison on plant tissues has yet to be carried out. METHODS: We performed an inter-method comparison of six plant water extraction techniques: direct vapour equilibration, microwave extraction, two unique versions of cryogenic vacuum distillation, centrifugation, and high-pressure mechanical squeezing. These methods were applied to four isotopically unique plant portions (head, stem, leaf, and root crown) of spring wheat (Triticum aestivum L.). Extracted plant water was analyzed via spectrometric (OA-ICOS) and mass-based (IRMS) analysis systems when possible. Spring wheat was grown under controlled conditions with irrigation inputs of a known isotopic composition. RESULTS: The tested methods of extraction yielded markedly different isotopic signatures. Centrifugation, microwave extraction, direct vapour equilibration, and high-pressure mechanical squeezing produced water more enriched in 2 H and 18 O content. Both cryogenic vacuum distillation systems and the high-pressure mechanical squeezing method produced water more depleted in 2 H and 18 O content, depending upon the plant portion extracted. The various methods also produced differing concentrations of co-extracted organic compounds, depending on the mode of extraction. Overall, the direct vapor equilibration method outperformed all other methods. CONCLUSIONS: Despite its popularity, cryogenic vacuum distillation was outperformed by the direct vapor equilibration method in terms of limited co-extraction of volatile organic compounds, rapid sample throughput, and near instantaneous returned stable isotope results. More research is now needed with other plant species, especially woody plants, to see how far the findings from this study could be extended.

Platelet phenotype changes associated with breast cancer and its treatment.

Platelets and their granular contents influence both angiogenesis and breast cancer progression. This study was performed to assess the effect of breast cancer and its treatment on platelet biology and the response to inhibition of the platelet P2Y12 receptor. Receptor-specific platelet activation and inhibition was studied for three platelet-associated proteins important in cancer angiogenesis and progression, vascular endothelial growth factor (VEGF), thrombospondin1 (TSP1), and transforming growth factor beta 1 (TGF-ß1). Twenty-four women with active breast cancer and 10 healthy controls not receiving antiplatelet therapy participated in the study. Ex vivo activation of platelets in whole blood was accomplished using PAR1AP, PAR4AP, convulxin, and ADP. Platelet inhibition was accomplished using the P2Y12 receptor antagonist cangrelor (the in vitro equivalent of clopidogrel). VEGF, TSP1, and TGF-ß1 were measured using standard ELISA. Platelet activation by ADP, PAR1, PAR4, and collagen receptors increased VEGF, TSP1, and TGF-ß1 secretion in patients with breast cancer. Agonist-induced release of VEGF was greater in cancer patients as compared to healthy controls (p = 0.02 for ADP, p < 0.001 for PAR1AP, PAR4AP, and convulxin) despite a decrease in the efficiency of VEGF secretion in patients with breast cancer. These differences were not observed for TSP1 and TGF-ß1 secretion. P2Y12 receptor inhibition decreased VEGF, TSP1, and TGF-ß1 secretion. In patients with cancer, cangrelor inhibited TSP1 release to a greater extent than VEGF and TGF-ß1 release. In patients with breast cancer, the magnitude of platelet inhibition achieved by cangrelor was greater than that achieved with healthy controls for all agonists and platelet proteins studied. While platelets are known to influence progression of breast cancer, our results show that breast cancer and its treatment influence the platelet phenotype by increasing the secretion of pro-angiogenic proteins following platelet activation, modulating the efficiency of platelet protein release as well as increasing the response to antiplatelet therapy.

Evolving technologies for growing, imaging and analyzing 3D root system architecture of crop plants.

A plant's ability to maintain or improve its yield under limiting conditions, such as nutrient deficiency or drought, can be strongly influenced by root system architecture (RSA), the three-dimensional distribution of the different root types in the soil. The ability to image, track and quantify these root system attributes in a dynamic fashion is a useful tool in assessing desirable genetic and physiological root traits. Recent advances in imaging technology and phenotyping software have resulted in substantive progress in describing and quantifying RSA. We have designed a hydroponic growth system which retains the three-dimensional RSA of the plant root system, while allowing for aeration, solution replenishment and the imposition of nutrient treatments, as well as high-quality imaging of the root system. The simplicity and flexibility of the system allows for modifications tailored to the RSA of different crop species and improved throughput. This paper details the recent improvements and innovations in our root growth and imaging system which allows for greater image sensitivity (detection of fine roots and other root details), higher efficiency, and a broad array of growing conditions for plants that more closely mimic those found under field conditions.

Pharmacodynamic Effects When Clopidogrel is Given Before Cangrelor Discontinuation.

OBJECTIVE: To determine whether initiation of clopidogrel before discontinuation of cangrelor would impact on the recovery of platelet reactivity. BACKGROUND: The active metabolite of clopidogrel cannot bind to P2Y12 when cangrelor occupies the receptor. Pharmacodynamic studies have shown that this interaction is avoided when clopidogrel is given at the end of the cangrelor infusion. We found that antiplatelet effects of another thienopyridine, prasugrel, were apparent when prasugrel was administered 0.5 hour before cangrelor was stopped. METHODS: Platelet function studies (light transmission aggregometry, VerifyNow, and flow cytometry) were performed on blood from patients with stable coronary artery disease who were taking aspirin when a loading dose of clopidogrel (600 mg) was given during a cangrelor infusion (0.5 and 1 hour before cangrelor was stopped). Results were compared with those obtained when clopidogrel was given immediately after cangrelor was stopped. RESULTS: Administration of clopidogrel 0.5 and 1 hour before discontinuation of the cangrelor infusion did not prevent recovery of platelet reactivity more effectively than administration at the end of the infusion. CONCLUSION: Our results support the previously established strategy of administering clopidogrel immediately after discontinuation of cangrelor. Earlier administration increases the recovery of platelet function.

Functional, structural and phylogenetic analysis of domains underlying the Al sensitivity of the aluminum-activated malate/anion transporter, TaALMT1.

Triticum aestivum aluminum-activated malate transporter (TaALMT1) is the founding member of a unique gene family of anion transporters (ALMTs) that mediate the efflux of organic acids. A small sub-group of root-localized ALMTs, including TaALMT1, is physiologically associated with in planta aluminum (Al) resistance. TaALMT1 exhibits significant enhancement of transport activity in response to extracellular Al. In this study, we integrated structure-function analyses of structurally altered TaALMT1 proteins expressed in Xenopus oocytes with phylogenic analyses of the ALMT family. Our aim is to re-examine the role of protein domains in terms of their potential involvement in the Al-dependent enhancement (i.e. Al-responsiveness) of TaALMT1 transport activity, as well as the roles of all its 43 negatively charged amino acid residues. Our results indicate that the N-domain, which is predicted to form the conductive pathway, mediates ion transport even in the absence of the C-domain. However, segments in both domains are involved in Al(3+) sensing. We identified two regions, one at the N-terminus and a hydrophobic region at the C-terminus, that jointly contribute to the Al-response phenotype. Interestingly, the characteristic motif at the N-terminus appears to be specific for Al-responsive ALMTs. Our study highlights the need to include a comprehensive phylogenetic analysis when drawing inferences from structure-function analyses, as a significant proportion of the functional changes observed for TaALMT1 are most likely the result of alterations in the overall structural integrity of ALMT family proteins rather than modifications of specific sites involved in Al(3+) sensing.

Analysis of the small RNA spf in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000.

Bacteria contain small non-coding RNAs (ncRNAs) that are typically responsible for altering transcription, translation or mRNA stability. ncRNAs are important because they often regulate virulence factors and susceptibility to various stresses. Here, the regulation of a recently described ncRNA of Pseudomonas syringae DC3000, spot 42 (now referred to as spf), was investigated. A putative RpoE binding site was identified upstream of spf in strain DC3000. RpoE is shown to regulate the expression of spf. Also, deletion of spf results in increased sensitivity to hydrogen peroxide compared with the wild-type strain, suggesting that spf plays a role in susceptibility to oxidative stress. Furthermore, expression of alg8 is shown to be influenced by spf, suggesting that this ncRNA plays a role in alginate biosynthesis. Structural and comparative genomic analyses show this ncRNA is well conserved among the pseudomonads. The findings provide new information on the regulation and role of this ncRNA in P. syringae.

How is forearm compliance affected by various circumferential dressings?

BACKGROUND: The forearm is the second most common location for extremity compartment syndrome. Compliance is a physical property that describes a material's ability to expand with an increasing internal volume. The effect of circumferential dressings on extremity pressures has been investigated in various animal models and in some nonphysiologic mechanical models, but the importance of this effect has not been fully investigated in the human upper extremity. In addition, the physical property of compliance has not been reported in the analysis of compartment volume-pressure relationships. QUESTIONS/PURPOSES: We created a physiologic cadaver model for acute compartment syndrome in the human forearm to determine (1) how much volume is required to reach the pressure threshold of 50 mm Hg in forearms, undressed and dressed with various circumferential dressings, (2) differences in forearm compliances that result from dressings, and (3) whether univalving or bivalving of those dressings adequately reduces compartment pressures. METHODS: A sealed inflatable bladder was placed deep in the volar compartment of seven fresh-frozen cadaveric forearms and overlying fascia and skin were closed. Compartment pressures were measured as saline was infused in the bladder, and compliance was calculated from pressure versus volume curves. This was repeated for each specimen using five external wraps, splints, and casts. At a baseline of 50 mm Hg, each dressing then was univalved (and bivalved, when appropriate for the material) and the decrease in compartment pressure was measured. For each of the seven cadaver forearms, one test was performed without dressings and then for each of five dressing conditions. RESULTS: Forearms in fiberglass casts accommodated only a mean of 19 mL (SD, 11 mL; 95% CI, 9-28 mL) before reaching the 50 mm Hg pressure threshold, which was much less than in undressed forearms (mean, 77 mL; SD, 25 mL; 95% CI, 55-98 mL; p < 0.001). Mean compliances were as follows: ACE™ wrap (1.75 mL/mm Hg; SD, 0.41 mL/mm Hg), Webril™ (1.54 mL/mm Hg; SD, 0.56 mL/mm Hg), Kling(®) (1.23 mL/mm Hg; SD, 0.52 mL/mm Hg), sugar tong splint (1.05 mL/mm Hg; SD, 0.52 mL/mm Hg), and fiberglass cast (0.38 mL/mm Hg; SD, 0.27 mL/mm Hg). Univalving of all circumferential wraps dropped the mean compartment pressure from the 50 mm Hg starting point: ACE™ (46%; SD, 14%), Webril™ (52%; SD, 20%), Kling(®) (70%; SD, 18%), sugar tong splint (52%; SD, 19%), and fiberglass cast (58%; SD, 7%), with p less than 0.001 for all dressings. CONCLUSIONS: We observed the compressive effect of various commonly used upper-extremity splints and wraps, finding the least amount of accommodation afforded by fiberglass casts. Univalve release resulted in reduction in forearm compartment pressures, even in fiberglass casts. CLINICAL RELEVANCE: A rigid circumferential dressing can have a dramatic effect on extremity compartment compliance. Contrary to common clinical teaching, univalving of forearm circumferential dressings effectively reduced compartment pressures, as shown in this physiologic model.

Platelet FcγRIIa expression in patients with stable coronary artery disease.

OBJECTIVES: FcÉ£RIIa amplifies platelet activation and greater expression increases platelet reactivity. In patients with myocardial infarction (MI), high platelet FcÉ£RIIa identifies patients with an approximately 4-fold greater risk of MI, stroke, and death. We compared platelet FcÉ£RIIa in 2 groups: (1) patients who had not had an MI in the previous year and were undergoing cardiac catheterization and percutaneous coronary intervention (PCI) labeled as stable coronary artery disease (CAD), and (2) previously obtained results in patients with MI (n = 197). METHODS: Patients undergoing cardiac catheterization and PCI were enrolled. FcÉ£RIIa expression was quantified with the use of flow cytometry. Comparisons were made with Mann-Whitney Rank Sum Test and Chi Squared analysis. Significance was defined as P less than .05. RESULTS: Compared to patients with MI, patients with stable CAD (n = 49) were older (70 ± 9 years vs 63 ± 12 years) and were more likely to have had prior MI (43% vs 23%), prior revascularization (62% vs 33%), diabetes (35% vs 24%), and hypertension (98% vs 66%). In patients with stable CAD, platelet FcÉ£RIIa was, on average, lower than that seen in patients with acute MI (9746 ± 4316 vs 11 479 ± 2405 molecules/platelet, P less than .001). Patients with stable CAD exhibited a range of platelet FcÉ£RIIa (~4500 to ~27 000 molecules/platelet) similar to that seen in acute MI patients (~6500 to ~30 000 molecules/platelet). CONCLUSIONS: Compared to patients with MI, patients with stable CAD had, on average, lower platelet FcÉ£RIIa. However, the range of platelet FcÉ£RIIa was similar to that seen in patients with MI. These results support future studies designed to assess the prognostic implications of platelet FcÉ£RIIa in patients with stable CAD.

New role for cardiomyocyte Bmal1 in the regulation of sex-specific heart transcriptomes.

It has been well established that cardiovascular diseases exhibit significant differences between sexes in both preclinical models and humans. In addition, there is growing recognition that disrupted circadian rhythms can contribute to the onset and progression of cardiovascular diseases. However little is known about sex differences between the cardiac circadian clock and circadian transcriptomes in mice. Here, we show that the the core clock genes are expressed in common in both sexes but the circadian transcriptome of the mouse heart is very sex-specific. Hearts from female mice expressed significantly more rhythmically expressed genes (REGs) than male hearts and the temporal pattern of REGs was distinctly different between sexes. We next used a cardiomyocyte-specific knock out of the core clock gene, Bmal1, to investigate its role in sex-specific gene expression in the heart. All sex differences in the circadian transcriptomes were significantly diminished with cardiomyocyte-specific loss of Bmal1. Surprisingly, loss of cardiomyocyte Bmal1 also resulted in a roughly 8-fold reduction in the number of all the differentially expressed genes between male and female hearts. We conclude that cardiomyocyte-specific Bmal1, and potentially the core clock mechanism, is vital in conferring sex-specific gene expression in the adult mouse heart.

Increased local cytokine production at culprit superficial femoral artery plaques.

Characterization of local inflammation at culprit superficial femoral artery (SFA) stenosis has not been studied. We hypothesized that arterial cytokine concentrations would be greater at sites of stenosis. Twenty patients with ≥50 % angiographic stenosis of the SFA had blood drawn just proximal to the lesion and from a contralateral site free of disease. A microplate immunoassay was used to determine the concentrations of 42 distinct cytokines and growth factors. Exact conditional logistic analysis was used to compare measures at the two sites with interaction terms describing clinical factors used to identify difference mediators. Interaction terms identified clinical factors that could predict cytokine levels. The concentrations of soluble CD40 ligand (sCD40L; mean 212 and 177 pg/ml, p = 0.01) and tumor necrosis factor beta (TNF-B; mean 16.6 and 15.9 pg/ml, p = 0.04) were increased immediately proximal to areas of stenosis. Factors associated with greater concentrations at sites of stenosis were bilateral ankle-brachial index ≤0.90 (p = 0.04), no statin use (p = 0.02), claudication (p = 0.03), low leukocyte count (p = 0.03), absence of limb ischemia (p = 0.04) and lack of aspirin or clopidogrel therapy (p ≤ 0.06). Greater concentrations of sCD40L and TNF-B at sites of stenosis suggest that these cytokines play a role in the pathogenesis of symptomatic SFA disease. Our results also suggest that statin, aspirin and clopidogrel therapy may attenuate localized inflammation in the SFA, though due to a small sample size and the use of multiple comparisons across groups, these findings can be viewed as hypothesis generating only. In conclusion, selected cytokines are heightened at culprit SFA lesions and inflammation may be modulated by statin and antiplatelet therapy.