Dodecafluoropentane Emulsion in Acute Ischemic Stroke: A Phase Ib/II Randomized and Controlled Dose-Escalation Trial.

PURPOSE: This randomized, placebo-controlled, double-blind, dose-escalation acute ischemic stroke trial was designed to demonstrate maximum tolerated dose, characterize adverse events (AEs), and explore clinical outcomes when intravenous dodecafluoropentane emulsion (DDFPe) was used as neuroprotection. METHODS: Acute ischemic stroke patients (n = 24) with National Institutes of Health Stroke Scale (NIHSS) score of 2-20 were randomized to either 3 doses of intravenous DDFPe or placebo, 1 every 90 minutes, starting within 12 hours of symptom onset. Doses were given without affecting standard stroke care. Each of the 3 dose cohorts included 8 patients, with 2 receiving placebo and 6 receiving DDFPe. Primary outcomes were serious adverse events (SAEs), AEs, NIHSS score, and modified Rankin Score (mRS). RESULTS: No dose-limiting toxicities were encountered, and no maximum tolerated dose was defined. One unrelated delayed death occurred in a DDFPe patient, and another occurred in the placebo group. Group SAEs and AEs were similar in incidence and severity. Early initiation of DDFPe treatment resulted in better NIHSS score response than late initiation (P = .03). Thirty- and 90-day mRS after high-dose therapy suggested clinical improvement (P = .01 and P = .03, respectively). However, the significance of differences in clinical outcomes was limited by small patient numbers and differences in stroke severity between cohorts. CONCLUSIONS: Intravenous DDFPe appears to be safe at all doses tested. Clinical improvements in NIHSS score and mRS were significant but compromised by small sample size.

U.S. Physician-Scientist Workforce in the 21st Century: Recommendations to Attract and Sustain the Pipeline.

The U.S. physician-scientist (PS) workforce is invaluable to the nation's biomedical research effort. It is through biomedical research that certain diseases have been eliminated, cures for others have been discovered, and medical procedures and therapies that save lives have been developed. Yet, the U.S. PS workforce has both declined and aged over the last several years. The resulting decreased inflow and outflow to the PS pipeline renders the system vulnerable to collapsing suddenly as the senior workforce retires. In November 2015, the Alliance for Academic Internal Medicine hosted a consensus conference on the PS workforce to address issues impacting academic medical schools, with input from early-career PSs based on their individual experiences and concerns. One of the goals of the conference was to identify current impediments in attracting and supporting PSs and to develop a new set of recommendations for sustaining the PS workforce in 2016 and beyond. This Perspective reports on the opportunities and factors identified at the conference and presents five recommendations designed to increase entry into the PS pipeline and nine recommendations designed to decrease attrition from the PS workflow.

Recruiting Faculty Leaders at U.S. Medical Schools: A Process Without Improvement?

Recruiting faculty leaders to work in colleges of medicine is a ubiquitous, time-consuming, costly activity. Little quantitative information is available about contemporary leadership recruiting processes and outcomes. In this article, the authors examine current recruiting methods and outcomes in colleges of medicine and compare academic search approaches with the approaches often employed in intellectual-capital-rich industries.In 2015, the authors surveyed chairs of internal medicine at U.S. medical schools regarding their recruiting practices and outcomes-specifically their selection methods, the duration of searches, the recruitment of women and minorities underrepresented in medicine (URM), and their satisfaction with search outcomes.The authors found that department chairs were extensively engaged in numerous searches for leaders. The recruitment process most commonly required 7 to 12 months from initiation to signed contract. Interestingly, longer searches (19+ months) were much more frequently associated with a recruitment outcome that chairs viewed as unsatisfactory or very unsatisfactory. Most leadership searches produced very few women and URM finalists. The biggest perceived hurdles to successful recruitment were the need to relocate the candidate and family and the shortage of good candidates.The process of recruiting leaders in academic medicine has changed little in more than 25 years. Process improvement is important and should entail carefully structured search processes, including both an overhaul of search committees and further emphasis on leadership development within the college of medicine. The authors propose specific steps to enhance recruitment of members of URM groups and women to leadership positions in academic medicine.

Cigarette Smoking-Associated Alterations in Serotonin/Adrenalin Signaling Pathways of Platelets.

BACKGROUND: Cigarette smoking plays a major role in cardiovascular diseases. The acute effects of cigarette smoking produce central nervous system-mediated activation of the sympathetic nervous system. The overactive sympathetic nervous system stimulates the secretion of serotonin (5-HT) and catecholamine into blood at supraphysiological levels. The correlation between these pathological conditions induced by smoking and the increased risk of thrombosis has not been thoroughly investigated. The goal of our study was to explore cigarette smoking-associated changes in platelet biology mediated by elevated 5-HT and catecholamine levels in blood plasma. METHODS AND RESULTS: Using blood samples collected from healthy nonsmokers and smokers (15 minutes after smoking), we determined that cigarette smoking increased the plasma 5-HT/catecholamine concentration by several fold and the percent aggregation of platelets 2-fold. Liquid chromatography-tandem mass spectrometry analysis of proteins eluted from platelet plasma membranes of smokers and nonsmokers demonstrated that GTPase-activating proteins and proteins participating in the actin cytoskeletal network were differentially and significantly elevated in smokers' platelet membranes compared with those of nonsmokers. Interestingly, Matrix-assisted laser desorption/ionization-mass spectrometry analyses of the glycans eluted from platelet plasma membranes of the smokers demonstrated that the level and structures of glycans are different from the nonsmokers' platelet surface glycans. Pharmacological blockade of 5-HT or catecholamine receptors counteracted the 5-HT/catecholamine-mediated aggregation and altered the level and composition of glycan on platelet surfaces. CONCLUSIONS: Based on our findings, we propose that smoking-associated 5-HT/catecholamine signaling accelerates the trafficking dynamics of platelets, and this remodels the surface proteins and glycans and predisposes platelets to hyperactive levels. Smokers' platelets also had correspondingly higher resting concentrations of intracellular calcium and transglutaminase activity. These findings suggest a link among smoking, platelet 5-HT, catecholamine signaling, and their downstream effectors-including phospholipase C and inositol-1,4,5-triphosphate pathways-resulting in an increased tonic level of platelet activation in smokers.

Platelet function testing to predict hyporesponsiveness to clopidogrel in patients with chest pain seen in the emergency department.

BACKGROUND: A dual antiplatelet regimen has been shown to reduce the risk of major adverse cardiovascular events after percutaneous coronary intervention. However, there is little information available on inhibition of platelet aggregation in patients with a prior coronary stent presenting with chest pain. This study evaluated the prevalence of hyporesponsiveness to clopidogrel and factors associated with this in patients presenting to our emergency department with chest pain who had previously undergone coronary stent placement and were prescribed dual antiplatelet therapy. METHODS: Responsiveness to clopidogrel was evaluated in a cohort of 533 consecutive stented patients presenting to the emergency department with chest pain. P2Y12 reaction units (PRU) and percent P2Y12 inhibition with clopidogrel were measured in all patients. Of 533 patients, 221 (41.6%) had PRU ≥ 230. A multivariate logistic regression model was used to determine the relationship between hyporesponsiveness to clopidogrel (defined as PRU ≥ 230) and several potential risk factors, ie, gender, age, race, type 1 or type 2 diabetes, hypertension, smoking, chronic renal failure, and obesity. RESULTS: There was a greater risk of hyporesponsiveness in African Americans than in non-African American patients (adjusted odds ratio [OR] = 2.165), in patients with type 2 diabetes than in those without (adjusted OR = 2.109), and in women than in men (adjusted OR = 1.813), as well as a greater risk of hyporesponsiveness with increasing age (adjusted OR = 1.167 per decade). CONCLUSION: There was a high prevalence of hyporesponsiveness to clopidogrel in patients presenting with chest pain and a prior coronary stent. Non-insulin-dependent diabetes mellitus and African American race were the strongest predictors of hyporesponsiveness to clopidogrel, followed by gender and age.

Innovative P-wave detection for discrimination between ventricular and supraventricular tachycardia in single-chamber ICDs: is the P-wave invisible during tachycardia?

AIMS: Differentiation between supraventricular tachycardia (SVT) and ventricular tachycardia (VT) remains a substantial clinical challenge in patients with single-chamber implantable cardioverter-defibrillators (ICDs) due to absence of visible P waves. Innovative optimization of intrathoracic electrogram (EGM) configuration will facilitate P-wave detection and rhythm differentiation during tachycardia. METHODS AND RESULTS: Innovative optimization of EGM configuration was originally performed to improve patient care. In this retrospective cohort study, we examined our database for records of 140 consecutive patients undergoing single-chamber ICD implantation. During the follow-ups of 61 included patients with optimized EGM configuration, 27 patients were identified to have VT and/or SVT. EGMs in the Can (generator) to superior vena cava (Can-SVC) configuration were compared with those conventionally from the Can to right ventricular coil (Can-RV coil) source in the same patients. In Can-SVC EGMs, the ratio of P/QRS amplitude was 14-fold higher (0.57 ± 0.08 vs. 0.04 ± 0.00, P < 0.001) compared with those in Can-RV coil EGMs during sinus rhythm. With Can-SVC configuration, the odds of atrioventricular dissociation detection in patients with VT was increased 15-fold (61.9% vs. 9.5% with Can-RV coil; odds ratio, 15.4; 95% confidence interval, 2.8 to 84.7; P = 0.0009). In patients with SVT, P-waves or retrograde P-waves were markedly more identifiable in Can-SVC configuration compared with Can-RV coil (odds ratio, 40; 95% confidence interval, 3.6 to 447.1; P = 0.0010). CONCLUSION: P-wave recognition by optimizing EGM configuration provides a novel diagnostic tool for differentiation between VT and SVT in single-chamber ICDs. A potential discrimination algorithm would provide a cost-effective approach to improving the qualitative outcomes.

Evolving role of platelet function testing in coronary artery interventions.

The substantial reduction in ischemic events provided by the dual antiplatelet regimen with aspirin and clopidogrel is well documented in patients with acute coronary syndrome and patients undergoing percutaneous coronary intervention. Recently the variable response to the antiplatelet agents has received considerable attention after several "boxed warnings" on clopidogrel. This led to intense controversy on pharmacokinetic, pharmacodynamic, and pharmacogenomic issues of antiplatelet drugs, especially clopidogrel. Research use of platelet function testing has been successfully validated in identifying new antiplatelet drugs like prasugrel and ticagrelor. These platelet function assays are no longer regarded just as a laboratory phenomenon but rather as tools that have been shown to predict mortality in several clinical trials. It is believed that suboptimal response to an antiplatelet regimen (pharmacodynamic effect) may be associated with cardiovascular, cerebrovascular, and peripheral arterial events. There has been intense controversy about this variable response of antiplatelet drugs and the role of platelet function testing to guide antiplatelet therapy. While the importance of routine platelet function testing may be uncertain, it may be useful in high-risk patients such as those with diabetes mellitus, diffuse three vessels coronary artery disease, left main stenosis, diffuse atherosclerotic disease, and those with chronic renal failure undergoing percutaneous coronary intervention. It could also be useful in patients with suspected pharmacodynamic interaction with other drugs to assure the adequacy of platelet inhibition. While we wait for definitive trials, a predictive prognostic algorithm is necessary to individualize antiplatelet therapy with P2Y12 inhibitors based on platelet function assays and genetic testing.

Stroke prevention and treatment.

The decline in stroke incidence and mortality in the U.S. over the past 20 years is reaching a plateau, and the number of strokes may actually start to increase as the population ages. However, recent clinical trials have demonstrated that there are numerous opportunities to improve stroke prevention strategies and also opportunities to effectively intervene in and treat acute strokes. For patients with diabetes and for those with prior strokes or transient ischemic attacks, it has become evident that aggressive low-density lipoprotein lowering with statin medications will decrease the risk for total and fatal strokes. Optimal anticoagulation and antiplatelet therapy for primary and secondary stroke prevention in atrial fibrillation is being carefully defined. With numerous novel factor Xa and direct thrombin inhibitor drugs completing phase III clinical trials, it is likely that additional oral anticoagulant drugs will be clinically available for stroke prevention soon. Additionally, a major clinical trial is nearing completion that may resolve the role of carotid stenting and carotid endarterectomy in primary and secondary stroke prevention. There are recent notable advances in the acute treatment of stroke. It is likely that the time window for thrombolysis for appropriate patients with strokes will be increased from 3 to 4.5 h, permitting the inclusion of more patients in this treatment approach. There is ongoing investigation of intra-arterial thrombolysis and of acute intra-arterial thrombus extraction for treatment of selected patients with strokes. Unlike the progress in treatment of ischemic strokes, treatment of hemorrhagic stroke is progressing more slowly.

Modification of cardiovascular ion channels by gene therapy.

Delivery of genes to the heart and vasculature for therapeutic purposes is an exciting strategy that is approaching clinical reality. Abnormalities of expression or function of ion channels is central to many cardiovascular diseases and gene delivery to modify ion channels is an appealing alternative to traditional therapy with small-molecule drugs. Potential therapeutic targets include hypertrophy and heart failure, atrioventricular node modification in atrial fibrillation, ventricular tachycardia and hypertension. Numerous approaches for gene delivery are under development, including use of tissue-specific promoters in viral vectors. For other applications, such as development of biological pacemakers, cells can be transduced with pacemaker genes in vitro, and then the cells implanted within the heart. There are short-term hurdles to therapeutic gene delivery to modify cardiovascular ion channels, but in the intermediate and longer term, the outlook is promising.

Delivery of ion channel genes to treat cardiovascular diseases.

Modifying ion channel expression and function in the heart and vasculature are potentially useful, novel approaches to managing cardiac hypertrophy, atrial fibrillation and hypertension. Calcium channels play a pivotal role in the heart and vasculature in controlling muscle contraction as well as other aspects of calcium-dependent signaling. The present investigation reports development of mutated L-type calcium channel beta subunits that are delivered by an adenoviral vector to vascular smooth muscle tissue. Wild type subunits serve a chaperone function for the pore-forming alpha(1C) subunit of the calcium channel, localize to the cell membrane and enhance calcium current. Conversely, mutated subunits function as dominant negative, defective chaperone molecules that disrupt targeting to the cell membrane and decrease calcium current. The dominant negative genes can be delivered in vitro and ex vivo, and have the potential to decrease arterial tone and lower blood pressure in vivo.

Statin therapy for stroke prevention.

BACKGROUND AND PURPOSE: Statins are widely used to reduce the risk of stroke in patients with coronary artery disease (CAD), but less so in patients without CAD. We reviewed recent trials for new evidence for the reduction in risk of stroke. SUMMARY OF REVIEW: In patients with CAD, moderate-intensity statin treatment has been associated with reductions in risk of stroke, with no increase in hemorrhagic stroke. Additionally, in the TNT trial, intensive lipid lowering provided further stroke risk reduction compared with moderate lipid lowering in patients with stable CAD. Evidence is now available that statin therapy also reduces stroke risk in patients without CAD but at high cardiovascular risk, or with diabetes mellitus. The SPARCL trial showed that intensive statin therapy started within 6 months after a cerebrovascular event significantly reduced stroke risk and stroke severity. Low cholesterol levels have been associated with increased risk of hemorrhagic stroke, but although an increased risk of hemorrhagic stroke was observed in patients with prior hemorrhagic stroke in SPARCL, this was not related to low-density lipoprotein cholesterol levels. Clinical trials have recruited few patients with both coronary and cerebrovascular disease, but these patients are also expected to experience significant cardiovascular benefit with statin therapy. CONCLUSIONS: Trial data show that statins reduce the risk of stroke, in addition to providing cardiovascular benefits. Consequently, physicians should consider statin therapy in all patients at high risk of stroke.

Design of mutant beta2 subunits as decoy molecules to reduce the expression of functional Ca2+ channels in cardiac cells.

Calcium influx through long-lasting ("L-type") Ca(2+) channels (Ca(V)) drives excitation-contraction in the normal heart. Dysregulation of this process contributes to Ca(2+) overload, and interventions that reduce expression of the pore-forming alpha(1) subunit may alleviate cytosolic Ca(2+) excess. As a molecular approach to disrupt the assembly of Ca(V)1.2 (alpha(1C)) channels at the cell membrane, we targeted the Ca(2+) channel beta(2) subunit, an intracellular chaperone that interacts with alpha(1C) via its beta interaction domain (BID) to promote Ca(V)1.2 channel expression. Recombinant adenovirus expressing either the full beta(2) subunit (Full-beta(2)) or truncated beta(2) subunit constructs lacking either the C terminus, N terminus, or both (N-BID, C-BID, and BID, respectively) fused to green fluorescent protein were developed as potential decoys and overexpressed in HL-1 cells. Fluorescence microscopy revealed that the localization of Full-beta(2) at the surface membrane was associated with increased Ca(2+) current mainly attributed to Ca(V)1.2 channels. In contrast, truncated N-BID and C-BID constructs showed punctate intracellular expression, and BID showed a diffuse cytosolic distribution. Total expression of the alpha(1C) protein of Ca(V)1.2 channels was similar between groups, but HL-1 cells overexpressing C-BID and BID exhibited reduced Ca(2+) current. C-BID and BID also attenuated Ca(2+) current associated with another L-type Ca(2+) channel, Ca(V)1.3, but they did not reduce transient Ca(2+) currents attributed to Ca(V)3 channels. These results suggest that beta(2) subunit mutants lacking the N terminus may preferentially disrupt the proper localization of L-type Ca(2+) channels in the cell membrane. Cardiac-specific delivery of these decoy molecules in vivo may represent a gene-based treatment for pathologies involving Ca(2+) overload.

Cardiac troponin-I: a predictor of prognosis in subarachnoid hemorrhage.

BACKGROUND: Release of cardiac biomarkers is reported in patients with subarachnoid hemorrhage (SAH). Data addressing the impact of cardiac injury on outcome in these patients is sparse. This study was conducted to ascertain the association of elevation of serum cardiac Troponin-I (cTnI) with mortality and neurological outcome in patients with SAH. METHODS: Medical records of all patients admitted with a diagnosis of SAH and at least one measured cTnI were reviewed. Demographic and clinical variables including admission neurological status were collected. Conservative and non-parametric statistics were used to assess association between cTnI and death or neurological outcome at discharge. RESULTS: The study group comprised of 83 patients with a mean age of 59 years. There was a female (60%) and African-American (60%) preponderance. At admission, the median Glasgow Coma Scale (GCS) was 9, and 47% had a severe Hunt-Hess grade (HHG) of > or =4. Elevation of cTnI was found in 31 (37%) patients and was associated with worse baseline Fisher grade (p=0.01) and neurological status: GCS score (p=0.006) and HHG (p=0.007). Patients with abnormal cTnI were more likely to die (55% vs.27%; odds ratio 1.3-8.4, p = 0.01) and had a worse GCS score (p = 0.008) and HHG (p = 0.004) on discharge. On multivariate analysis, peak cTnI (p = 0.04) and admission GCS score of <12 (p = 0.02) were independent predictors of death at discharge. CONCLUSION: Patients with subarachnoid hemorrhage and elevated cTnI are found to have worse neurological status at admission. These patients have a worse neurological outcome and in-hospital mortality.

Inefficient glycosylation leads to high steady-state levels of actively degrading cardiac triadin-1.

In junctional sarcoplasmic reticulum, binding to cardiac triadin-1 provides a mechanism by which the Ca(2+)-release channel/ryanodine receptor may link with calsequestrin to regulate Ca(2+) release. Calsequestrin and triadin-1 both contain N-linked glycans, but about half of triadin-1 in the heart remains unglycosylated. To investigate mechanisms for this incomplete glycosylation, we overexpressed triadin-1 as a series of glycoform variants in non-muscle cell lines and neonatal heart cells using plasmid and adenoviral vectors. We showed that the characteristic incomplete glycosylation stemmed from properties of the glycosylation sequence that are conserved among triadin splice variants, including the close proximity of Asn(75) to the sarcoplasmic reticulum inner membrane. Although triadin-1 appeared by SDS-PAGE analysis as a 35/40-kDa doublet in all cells, variations occurred in the relative levels of the two glycoforms depending on the cell type and whether overexpression involved a plasmid or adenoviral vector. Treatment of triadin-1 with the proteasome inhibitor MG-132 led to striking changes in the relative levels of triadin-1 that indicated active breakdown of unglycosylated, but not glycosylated, triadin-1. Besides substantial increases in the relative levels of unglycosylated triadin-1, proteasome inhibition led to an accumulation of two new modified forms of triadin-1 that were seen with triadin-1 only when it is not glycosylated on Asn(75). Effects of tunicamycin and endoglycosidase H confirmed that these novel isoforms represent two alternative N-linked glycosylation sites, indicating that an alternative topology occurs infrequently leading to yet other glycoforms with short half-lives.

Detection of carotid stenosis in African Americans with ischemic heart disease.

OBJECTIVES: This study was conducted to define the frequency of internal carotid stenosis in African American patients with ischemic heart disease (IHD). METHODS: We recruited 101 African American patients with IHD from a university medical center for carotid duplex examination. RESULTS: The frequency of >30%, >50%, and >70% stenosis was 21%, 11%, and 5%, respectively. Age >60 years (21% vs 3%, P < .01) and diabetes mellitus (22% vs 5%, P < .01) were predictors of unilateral stenosis of >50% and remained significant on multivariate testing. CONCLUSION: African American patients with established IHD have higher rates of extracranial carotid stenosis than community dwelling African American subjects and comparable rates with other populations.