Differential sympathetic outflow to adipose depots is required for visceral fat loss in response to calorie restriction.

The sympathetic nervous system (SNS) regulates energy homeostasis in part by governing fatty acid liberation from adipose tissue. We first examined whether SNS activity toward discrete adipose depots changes in response to a weight loss diet in mice. We found that SNS activity toward each adipose depot is unique in timing, pattern of activation, and habituation with the most dramatic contrast between visceral and subcutaneous adipose depots. Sympathetic drive toward visceral epididymal adipose is more than doubled early in weight loss and then suppressed later in the diet when weight loss plateaued. Coincident with the decline in SNS activity toward visceral adipose is an increase in activity toward subcutaneous depots indicating a switch in lipolytic sources. In response to calorie restriction, SNS activity toward retroperitoneal and brown adipose depots is unaffected. Finally, pharmacological blockage of sympathetic activity on adipose tissue using the ß3-adrenergic receptor antagonist, SR59230a, suppressed loss of visceral adipose mass in response to diet. These findings indicate that SNS activity toward discrete adipose depots is dynamic and potentially hierarchical. This pattern of sympathetic activation is required for energy liberation and loss of adipose tissue in response to calorie-restricted diet.

Once versus twice daily aspirin after coronary bypass surgery: a randomized trial.

Essentials Coronary artery bypass graft (CABG) failure is associated with myocardial infarction and death. We tested whether more frequent dosing improves aspirin (ASA) response following CABG surgery. Twice-daily compared with once-daily dosing reduces ASA hyporesponsiveness after CABG surgery. The efficacy of twice-daily ASA needs to be tested in a trial powered for clinical outcomes. SUMMARY: Background Acetyl-salicylic acid (ASA) hyporesponsiveness occurs transiently after coronary artery bypass graft (CABG) surgery and may compromise the effectiveness of ASA in reducing thrombotic graft failure. A reduced response to ASA 81 mg once-daily after CABG surgery is overcome by four times daily ASA dosing. Objectives To determine whether ASA 325 mg once-daily or 162 mg twice-daily overcomes a reduced response to ASA 81 mg once-daily after CABG surgery. Methods Adults undergoing CABG surgery were randomized to ASA 81 mg once-daily, 325 mg once-daily or 162 mg twice-daily. The primary outcome was median serum thromboxane B2 (TXB2 ) level on postoperative day 4. We pooled the results with those of our earlier study to obtain better estimates of the effect of ASA 325 mg once-daily or in divided doses over 24 h. Results We randomized 68 patients undergoing CABG surgery. On postoperative day 4, patients randomized to receive ASA 81 mg once-daily had a median day 4 TXB2 level of 4.2 ng mL-1 (Q1, Q3: 1.5, 7.5 ng mL-1 ), which was higher than in those randomized to ASA 162 mg twice-daily (1.1 ng mL-1 ; Q1, Q3: 0.7, 2.7 ng mL-1 ) and similar to those randomized to ASA 325 mg once-daily (1.9 ng mL-1 ; Q1, Q3: 0.9, 4.7 ng mL-1 ). Pooled data showed that the median TXB2 level on day 4 in groups receiving ASA 162 mg twice-daily or 81 mg four times daily was 1.1 ng mL-1 compared with 2.2 ng mL-1 in those receiving ASA 325 mg once-daily. Conclusions Multiple daily dosing of ASA is more effective than ASA 81 mg once-daily or 325 mg once-daily at suppressing serum TXB2 formation after CABG surgery. A twice-daily treatment regimen needs to be tested in a clinical outcome study.

A new brain dopamine-deficient Drosophila and its pharmacological and genetic rescue.

Dopamine (DA) is a neurotransmitter with conserved behavioral roles between invertebrate and vertebrate animals. In addition to its neural functions, in insects DA is a critical substrate for cuticle pigmentation and hardening. Drosophila tyrosine hydroxylase (DTH) is the rate limiting enzyme for DA biosynthesis. Viable brain DA-deficient flies were previously generated using tissue-selective GAL4-UAS binary expression rescue of a DTH null mutation and these flies show specific behavioral impairments. To circumvent the limitations of rescue via binary expression, here we achieve rescue utilizing genomically integrated mutant DTH. As expected, our DA-deficient flies have no detectable DTH or DA in the brain, and show reduced locomotor activity. This deficit can be rescued by l-DOPA/carbidopa feeding, similar to human Parkinson's disease treatment. Genetic rescue via GAL4/UAS-DTH was also successful, although this required the generation of a new UAS-DTH1 transgene devoid of most untranslated regions, as existing UAS-DTH transgenes express in the brain without a Gal4 driver via endogenous regulatory elements. A surprising finding of our newly constructed UAS-DTH1m is that it expresses DTH at an undetectable level when regulated by dopaminergic GAL4 drivers even when fully rescuing DA, indicating that DTH immunostaining is not necessarily a valid marker for DA expression. This finding necessitated optimizing DA immunohistochemistry, showing details of DA innervation to the mushroom body and the central complex. When DA rescue is limited to specific DA neurons, DA does not diffuse beyond the DTH-expressing terminals, such that DA signaling can be limited to very specific brain regions.

Medical device-induced thrombosis: what causes it and how can we prevent it?

Blood-contacting medical devices, such as vascular grafts, stents, heart valves, and catheters, are often used to treat cardiovascular diseases. Thrombus formation is a common cause of failure of these devices. This study (i) examines the interface between devices and blood, (ii) reviews the pathogenesis of clotting on blood-contacting medical devices, (iii) describes contemporary methods to prevent thrombosis on blood-contacting medical devices, (iv) explains why some anticoagulants are better than others for prevention of thrombosis on medical devices, and (v) identifies future directions in biomaterial research for prevention of thrombosis on blood-contacting medical devices.

Active metabolite concentration of clopidogrel in patients taking different doses of aspirin: results of the interaction trial.

BACKGROUND: The CURRENT-OASIS-7 and PLATO trials suggest that the benefit of clopidogrel is influenced by the dose of aspirin. OBJECTIVE: To explore a potential pharmacokinetic interaction between aspirin and clopidogrel, and determinants of clopidogrel active metabolite (AM) levels. METHODS: In part 1, using a 2 × 2 factorial design, we randomized patients to clopidogrel 600 mg loading dose (LD) followed by 150 mg day(-1) for 6 days and 75 mg day(-1) thereafter, or clopidogrel 300 mg LD followed by 75 mg day(-1) thereafter, and compared aspirin at 325 mg or 81 mg day(-1) . In part 2, patients were given a 600-mg clopidogrel LD, and were randomly allocated to aspirin 325 mg or 81 mg day(-1) . We combine the data from the two parts. Blood samples were collected 1 h after administration of the study drug. RESULTS: We randomized 302 patients (mean age 60.4 ± 9.9 years). Clopidogrel AM levels were similar in patients randomized to aspirin 325 or 81 mg (geometric mean, 12.70 ng mL(-1) ; 95% CI, 10.96-14.72 ng mL(-1) ; and geometric mean, 12.55 ng mL(-1) ; 95% CI, 10.80-14.58 ng mL(-1) ; P = 0.91). Blood levels of clopidogrel were lower in CYP2C19*2 loss-of-function (LOF) carriers compared with non-carriers (10.72 ng mL(-1) ; 95% CI, 8.83-13.01 ng mL(-1) ; and 15.21 ng mL(-1) ; 95% CI, 13.30-17.40 ng mL(-1) , respectively; P = 0.003) whereas levels in gain of function carriers and non-carriers were similar (13.31 ng mL(-1) ; 95% CI, 11.53-15.35 ng mL(-1) ; and 14.07 ng mL(-1) ; 95% CI, 11.74-16.87 ng mL(-1) , respectively; P = 0.4). Independent baseline predictors of clopidogrel AM levels were LOF genotype, body mass index, diabetes, proton pump inhibitor use and creatinine clearance, but accounted for only 20% of the variability in levels. CONCLUSION: Aspirin dose does not predict clopidogrel AM levels 1 h post-LD. Most of the variability in clopidogrel AM levels is not explained by patient characteristics or CYP2C19 metabolizer status.

Application and feasibility of systemic lupus erythematosus reproductive health care quality indicators at a public urban rheumatology clinic.

OBJECTIVES: Quality indicators (QIs) are evidence-based processes of care designed to represent the current standard of care. Reproductive health QIs for the care of patients with systemic lupus erythematosus (SLE) have recently been developed, and examine areas such as pregnancy screening for autoantibodies, treatment of pregnancy-associated antiphospholipid syndrome, and contraceptive counseling. This study was designed to investigate our performance on these QIs and to explore potential gaps in care and demographic predictors of adherence to the QIs in a safety-net hospital. METHODS: We performed a record review of patients with a diagnosis of SLE at Denver Health Medical Center (DH) through an electronic query of existing medical records and via chart review. Data were limited to female patients between the ages of 18 and 50 who were seen between July 2006 and August 2011. RESULTS: A total of 137 female patients between the ages of 18 and 50 were identified by ICD-9 code and confirmed by chart review to have SLE. Of these, 122 patients met the updated 1997 American College of Rheumatology SLE criteria and had intact reproductive systems. Only 15 pregnancies were documented during this five-year period, and adherence to autoantibody screening was 100 percent. We did not have any patients who were pregnant and met criteria for pregnancy-associated antiphospholipid syndrome. Sixty-five patients (53%) received potentially teratogenic medications, and 30 (46%) had documented discussions about these medications' potential risk upon their initiation. Predictors of whether patients received appropriate counseling included younger age (OR 0.92, CI 0.87-0.98) and those who did not describe English as their primary language (OR 0.24, CI 0.07-0.87) in the multivariate analysis. CONCLUSIONS: We were able to detect an important gap in care regarding teratogenic medication education to SLE patients of childbearing potential in our public health academic clinic, as only one in two eligible patients had documented appropriate counseling at the initiation of a teratogenic medication.

Multiple daily doses of acetyl-salicylic acid (ASA) overcome reduced platelet response to once-daily ASA after coronary artery bypass graft surgery: a pilot randomized controlled trial.

BACKGROUND: The efficacy of ASA for prevention of graft failure following CABG surgery may be limited by incomplete platelet inhibition due to increased post-operative platelet turnover. OBJECTIVES: To determine whether acetyl-salicylic acid (ASA) 325 mg once-daily or 81 mg four-times daily overcomes the impaired response to ASA 81 mg once-daily in post-operative coronary artery bypass graft (CABG) patients. METHODS: We randomized 110 patients undergoing CABG surgery to either ASA 81 mg once-daily, 81 mg four times daily or 325 mg once-daily and compared their effects on serum thromboxane B2 (TXB2 ) suppression and arachidonate-induced platelet aggregation. RESULTS: One hundred patients were included in the final analysis. Platelet counts fell after surgery, reached a nadir on day 2, and then gradually increased. Although there was near complete suppression of TXB2 on the second or third post-operative day, TXB2 levels increased in parallel with the rise in platelet count on subsequent days. This increase was most marked in patients receiving ASA 81 mg once-daily and less evident in those receiving ASA four times daily. On post-operative day 4, (i) median TXB2 levels were lower with four times daily ASA than with either ASA 81 mg once-daily (1.1 ng/mL; Quartile(Q) Q1,Q3: 0.5, 2.4 and 13.3 ng/mL; Q1,Q3: 7.8, 30.8 ng/mL, respectively; P < 0.0001) or ASA 325 mg once-daily (3.4 ng/mL; Q1,Q3: 2.0, 8.2 ng/mL; P = 0.002), and (ii) ASA given four times daily was more effective than ASA 81 mg once-daily and 325 mg once-daily at suppressing platelet aggregation. CONCLUSIONS: Four times daily ASA is more effective than ASA 81 and 325 mg once-daily at suppressing serum TXB2 formation and platelet aggregation immediately following CABG surgery.

Real-world variability in dabigatran levels in patients with atrial fibrillation.

BACKGROUND: In clinical practice, physicians are given the choice of selecting one of two dabigatran doses based on patient characteristics, with the lower dose typically used in patients at a higher risk of bleeding. OBJECTIVES: The objectives of the study were to (i) estimate the inter- and intra-patient variability in dabigatran levels with 110 mg (DE110) and 150 mg (DE150) doses, (ii) examine the effect of physicians' dose selection on levels in DE110 and DE150 subgroups, and (iii) explore whether a single trough measurement identifies patients with extreme levels on subsequent visits. METHODS: In this prospective observational study of 100 patients with atrial fibrillation (AF), peak and trough levels of dabigatran were measured with the Hemoclot(®) assay at baseline and every 2 months thereafter (maximum four visits). RESULTS: Inter-patient variability in dabigatran levels (geometric coefficient of variation [gCV], 51-64%) was greater than intra-patient variability (gCV, 32-40%). Similar medians and distributions of levels were observed in DE110 and DE150 subgroups. Patients receiving DE110 were older, had lower renal function and weighed less than those receiving DE150. Up to 40% of patients whose trough levels were in the upper extremes, and up to 80% of patients whose trough levels were in the lower extremes at baseline, showed subsequent levels that fell in the middle quartiles. CONCLUSIONS: Our data support the practice of selecting the dabigatran dose based upon clinical characteristics because it results in similar levels of drug exposure in patients given DE110 or DE150. They do not support the concept that a single Hemoclot(®) measurement reliably identifies patients with consistently high or low values.

Comparison of the effects of apixaban and rivaroxaban on prothrombin and activated partial thromboplastin times using various reagents.

BACKGROUND: Clinical situations occur where expedient assessment of the anticoagulant activity of the direct factor Xa (FXa) inhibitors is required. Although quantitative anti-FXa (FXa) assays can be used to measure plasma levels of apixaban or rivaroxaban, turnaround is often slow and many laboratories do not perform these assays. OBJECTIVE: We compared the in vitro effects of apixaban and rivaroxaban on two readily available laboratory tests, the prothrombin time (PT) and activated partial thromboplastin time (APTT), performed with different reagents. We aimed to identify the most sensitive reagents. METHODS: Rivaroxaban or apixaban was added to human plasma at a range of concentrations covering expected peak and trough levels, and concentrations were confirmed using calibrated anti-FXa assays. Samples were assayed with six PT and seven APTT reagents using different coagulometers. RESULTS AND CONCLUSIONS: TriniCLOT PT Excel S was the only reagent to demonstrate sensitivity to apixaban. All of the PT reagents were sensitive to rivaroxaban with TriniCLOT PT Excel S and HemosIL HS PLUS being the most sensitive. Sensitivity to rivaroxaban varied among APTT reagents; four reagents exhibited the greatest responsiveness, and of these, Actin FSL was the most responsive. Commonly used coagulation tests may be useful for assessing the anticoagulant effect of rivaroxaban but not of apixaban. The reason for the different effects of apixaban and rivaroxaban on the PT and APTT is unknown.

A guide to GRADE guidelines for the readers of JTH.

More than 70 organizations worldwide have adopted the GRADE methodology for guideline development. The ninth iteration of the American Collage of Chest Physicians guidelines (AT9) adopted structural and policy changes that resulted in a greater adherence to GRADE guidance than previous iterations. The most important of these changes include minimizing the impact of financial and intellectual conflict of interest, increasing the rigor of evidence evaluation, acknowledging uncertainty in estimates of typical values and preferences, and awareness of the large variability in values and preferences. One of the consequences of the greater adherence to GRADE methodology is an increase in weak vs. strong recommendations in AT9. The result of the GRADE process highlights the desirability of higher-quality evidence both regarding the outcomes of alternative management strategies and regarding the distribution of values and preferences in patients considering those alternatives. It also encourages shared decision making in encounters between physicians and patients. Although some physicians might find the uncertainty underlying medical practice discouraging or unsettling, relative to denying or obscuring the uncertainty, acknowledging and addressing the uncertainty will lead to more credible, realistic, and useful recommendations.

Methodology for the development of antithrombotic therapy and prevention of thrombosis guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND: To develop the Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: ACCP Evidence-Based Clinical Practice Guidelines (AT9), the American College of Chest Physicians (ACCP) assembled a panel of clinical experts, information scientists, decision scientists, and systematic review and guideline methodologists. METHODS: Clinical areas were designated as articles, and a methodologist without important intellectual or financial conflicts of interest led a panel for each article. Only panel members without significant conflicts of interest participated in making recommendations. Panelists specified the population, intervention and alternative, and outcomes for each clinical question and defined criteria for eligible studies. Panelists and an independent evidence-based practice center executed systematic searches for relevant studies and evaluated the evidence, and where resources and evidence permitted, they created standardized tables that present the quality of the evidence and key results in a transparent fashion. RESULTS: One or more recommendations relate to each specific clinical question, and each recommendation is clearly linked to the underlying body of evidence. Judgments regarding the quality of evidence and strength of recommendations were based on approaches developed by the Grades of Recommendations, Assessment, Development, and Evaluation Working Group. Panel members constructed scenarios describing relevant health states and rated the disutility associated with these states based on an additional systematic review of evidence regarding patient values and preferences for antithrombotic therapy. These ratings guided value and preference decisions underlying the recommendations. Each topic panel identified questions in which resource allocation issues were particularly important and, for these issues, experts in economic analysis provided additional searches and guidance. CONCLUSIONS: AT9 methodology reflects the current science of evidence-based clinical practice guideline development, with reliance on high-quality systematic reviews, a standardized process for quality assessment of individual studies and the body of evidence, an explicit process for translating the evidence into recommendations, disclosure of financial as well as intellectual conflicts of interest followed by management of disclosed conflicts, and extensive peer review.(AU)

Reversal of the anti-platelet effects of aspirin and clopidogrel.

BACKGROUND: Guidelines recommend stopping aspirin and clopidogrel 7 to 10 days before surgery to allow time for replacement of permanently inhibited platelets by newly released uninhibited platelets. OBJECTIVES: The purpose of the present study was to determine the rate of offset of the anti-platelet effects of aspirin and clopidogrel after stopping treatment and the proportion of untreated donor platelets that are required to reverse their anti-platelet effects. METHODS: Cohort 1 consisted of 15 healthy subjects who received aspirin 81 mg day(-1) or clopidogrel 75 mg day(-1) for 7 days and underwent serial blood sampling until platelet function testing results normalized. Cohort 2 consisted of 36 healthy subjects who received aspirin 325 mg day(-1), clopidogrel 75 mg day(-1), aspirin 81 mg day(-1) plus clopidogrel 75 mg day(-1) or no treatment for 7 days and underwent a single blood sampling. RESULTS: In cohort 1, arachidonic acid (AA)-induced light transmission aggregation (LTA) returned to baseline levels in all subjects within 4 days of stopping aspirin, coinciding with the partial recovery of plasma thromboxane B(2) concentrations. ADP-induced LTA did not return to baseline levels until 10 days after stopping clopidogrel. In cohort 2, AA-induced LTA in patient treated with aspirin reached control levels after mixing with 30% untreated donor platelets whereas ADP-induced LTA in patients treated with clopidogrel reached control levels only after the addition of 90% or more donor platelets. CONCLUSIONS: Platelet aggregation recovers within 4 days of stopping aspirin but clopidogrel must be stopped for 10 days to achieve a normal aggregatory response.

Randomized controlled trial of a new portable calf compression device (Venowave) for prevention of venous thrombosis in high-risk neurosurgical patients.

BACKGROUND: Patients undergoing neurosurgical procedures are at risk of venous thromboembolism (VTE), but often have contraindications for anticoagulant prophylaxis. OBJECTIVES: To assess the efficacy and tolerability of a new, lightweight, portable, battery-powered, intermittent calf compression device, Venowave, for the prevention of VTE in neurosurgical inpatients. PATIENTS/METHODS: We performed an open randomized controlled trial comparing Venowave with control for the prevention of VTE in patients undergoing neurosurgery. The primary outcome was the composite of asymptomatic deep vein thrombosis (DVT) detected by screening venography or compression ultrasound performed on day 9 (± 2 days) and symptomatic VTE. RESULTS: We randomized 75 patients to receive Venowave devices and 75 to the control group. All patients were prescribed graduated compression stockings and physiotherapy. VTE occurred in three patients randomized to Venowave and in 14 patients randomized to control (4.0% vs. 18.7%, relative risk 0.21; 95% confidence interval 0.05-0.75, P = 0.008). Similar reductions were seen for proximal DVT (2.7% vs. 8.0%) and symptomatic VTE (0% vs. 2.7%), and the results were consistent in all subgroups examined. CONCLUSIONS: Venowave devices are effective in preventing VTE in high-risk neurosurgical patients.

Tuberculosis testing in correctional officers: a national random survey of jails in the United States.

SETTING: The correctional system in the United States is large and growing. The Centers for Disease Control and Prevention recommend baseline and annual testing of employees in correctional facilities for latent tuberculosis infection (LTBI). OBJECTIVE: To describe the extent of and factors associated with LTBI testing practices for jail correctional officers. DESIGN: A national survey of 1760 randomly selected jails was conducted. We used multivariable logistic regression models to examine factors associated with testing officers in a guideline-concordant manner and having a written policy. RESULTS: A total of 1174 (67%) surveys were returned. Only 52% of jails had a written policy on LTBI testing of officers, and 51% screened officers at least annually (guideline concordance). Large jails (OR 2.41, 95%CI 1.67-3.49) and jails in states with a high tuberculosis incidence (OR 1.67, 95%CI 1.17-2.38) and in the Midwest (OR 1.58, 95%CI 1.07-2.33) were more likely to screen in a guideline-concordant manner. CONCLUSION: Screening for LTBI among correctional officers in the United States was inconsistent. Strategies to improve LTBI testing among correctional officers are needed.

Comparison of the anticoagulant intensities of fondaparinux and enoxaparin in the Organization to Assess Strategies in Acute Ischemic Syndromes (OASIS)-5 trial.

BACKGROUND: In the OASIS-5 trial, fondaparinux reduced major bleeding with similar short-term efficacy as enoxaparin but lowered death and stroke during long-term follow-up. The mechanism of lower bleeding and improved efficacy with fondaparinux is uncertain. METHODS AND RESULTS: We compared the anti-Xa concentration (reflecting drug levels), Xa clot time (reflecting anticoagulant effect) and endogenous thrombin potential (ETP; a global test of hemostatic function) in plasma samples collected 6, 24 and 72 h after the first dose of the study drug in 48 patients randomly assigned fondaparinux 2.5 mg day(-1) and 42 patients assigned enoxaparin 1 mg kg(-1) twice daily in the OASIS-5 trial. Patients assigned to fondaparinux compared with enoxaparin had a significantly lower mean anti-Xa level [0.52 IU mL(-1) (SD 0.22 IU mL(-1)) vs. 1.2 IU mL(-1) (SD 0.45 IU mL(-1)), P<0.0001] and Xa clot time [64.9 s (SD 17.7 s) vs. 111.8 s (SD 29.6 s), P<0.0001], and significantly higher ETP area under the curve (AUC) [386.7 mA (SD 51.5 mA) vs. 206.4 mA (SD 90.6 mA), P<0.001] at 6 h, and these differences remained evident at 24 and 72 h. There was significantly less variability of the results of anti-Xa levels, Xa clot time and ETP AUC for fondaparinux compared with enoxaparin at 6 h (P<0.001 for each comparison). CONCLUSION: Fondaparinux 2.5 mg day(-1) compared with enoxaparin 1 mg kg(-1) twice daily produces less variable anticoagulant effect and lower mean anticoagulant intensity. These results most likely explain the reduced risk of bleeding seen with fondaparinux compared with enoxaparin in the OASIS-5 trial and suggest that a lower intensity of anticoagulation than used in the past may be sufficient to prevent recurrent ischemic events and death in patients with ACS who are concurrently treated with aspirin and clopidogrel.

Antithrombotic and Thrombolytic Therapy

Since publication of the seventh American College of Chest Physicians (ACCP) supplement on antithrombotic and thrombolytic therapy, the results of clinical trials have provided important new information on the management of thromboembolic disorders, and the science of developing recommendations has advanced. In the accompanying supplement, we provide the new and updated recommendations and review several important changes that we have made in our guideline development process. We again made a conscious effort to increase the participation of female authors and contributors from outside North America, the latter reflecting the widespread use and dissemination of these guidelines internationally. The grading system for the recommendations was adopted in 2006 by the ACCP for all its guidelines, is similar to the increasingly widely used Grades of Recommendation, Assessment, Development, and Evaluation approach, and is described in detail in one of the introductory chapters. While most of the evidence on which recommendations are made remains low quality in fields of pediatric thrombosis, thrombosis in pregnancy, and thrombosis in valvular heart disease, rigorous studies in other fields have resulted in new and strong evidence-based recommendations for many indications.