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Biomedical subjects

Eric A Cohen

Publications and source records attributed to Eric A Cohen.

At least 37 records · Page 2Linked to original sources
PubMed2004

Long-term efficacy of bivalirudin and provisional glycoprotein IIb/IIIa blockade vs heparin and planned glycoprotein IIb/IIIa blockade during percutaneous coronary revascularization: REPLACE-2 randomized trial.

CONTEXT: In the Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE)-2 trial, bivalirudin with provisional glycoprotein IIb/IIIa (Gp IIb/IIIa) inhibition was found to be noninferior to heparin plus planned Gp IIb/IIIa blockade in the prevention of acute ischemic end points and was associated with significantly less bleeding by 30 days after percutaneous coronary intervention (PCI). OBJECTIVE: To determine whether the efficacy of bivalirudin remains comparable with that of heparin plus Gp IIb/IIIa blockade over 6 months and 1 year. DESIGN, SETTING, AND PARTICIPANTS: Follow-up study to 1 year of a randomized, double-blind trial conducted among 6010 patients undergoing urgent or elective PCI at 233 community or referral hospitals in 9 countries from October 2001 through August 2002. INTERVENTIONS: Patients were randomly assigned to receive intravenously bivalirudin (0.75 mg/kg bolus, 1.75 mg/kg per hour for the duration of PCI), with provisional Gp IIb/IIIa inhibition, or to receive heparin (65 U/kg bolus), with planned Gp IIb/IIIa inhibition (abciximab or eptifibatide). Both groups received daily aspirin and a thienopyridine for at least 30 days after PCI. MAIN OUTCOME MEASURES: Incidence of death, myocardial infarction, or repeat revascularization by 6 months and death by 12 months after enrollment. RESULTS: At 6 months, death occurred in 1.4% of patients in the heparin plus Gp IIb/IIIa group and in 1.0% of patients in the bivalirudin group (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.43-1.14; P =.15). Myocardial infarction occurred in 7.4% and 8.2% of patients, respectively (HR, 1.12; 95% CI, 0.93-1.34; P =.24), and repeat revascularization was required in 11.4% and 12.1% of patients, respectively (HR, 1.06; 95% CI, 0.91-1.23; P =.45). By 1 year, death occurred in 2.46% of patients treated with heparin plus Gp IIb/IIIa blockade and in 1.89% of patients treated with bivalirudin (HR, 0.78; 95% CI, 0.55-1.11; P =.16). Nonsignificant trends toward lower 1-year mortality with bivalirudin were present in all patient subgroups analyzed and were of greatest magnitude among high-risk patients. CONCLUSION: Long-term clinical outcome with bivalirudin and provisional Gp IIb/IIIa blockade is comparable with that of heparin plus planned Gp IIb/IIIa inhibition during contemporary PCI.

Abciximab↗
PubMed2004

A late role for the association of hnRNP A2 with the HIV-1 hnRNP A2 response elements in genomic RNA, Gag, and Vpr localization.

Two cis-acting RNA trafficking sequences (heterogenous ribonucleoprotein A2 (hnRNP A2)-response elements 1 and 2 or A2RE-1 and A2RE-2) have been identified in HIV-1 vpr and gag mRNAs and were found to confer cytoplasmic RNA trafficking in a murine oligodendrocyte assay. Their activities were assessed during HIV-1 proviral gene expression in COS7 cells. Single point mutations that were shown to severely block RNA trafficking were introduced into each of the A2REs. In both cases, this resulted in a marked decrease in hnRNP A2 binding to HIV-1 genomic RNA in whole cell extracts and hnRNP A2-containing polysomes. This also resulted in an accumulation of HIV-1 genomic RNA in the nucleus and a significant reduction in genomic RNA encapsidation levels. Immunofluorescence analyses revealed altered expression patterns for pr55Gag and particularly that for Vpr. Vpr localization became almost completely nuclear and this was reflected in a significant reduction in virion-associated Vpr levels. These effects coincided with late steps of the viral replication cycle and were not seen at early time points post-transfection. Transcription, splicing, steady state RNA levels, and pr55Gag processing were not affected. On the other hand, viral replication was markedly compromised in A2RE-2 mutant viruses and this correlated with lowered genomic RNA encapsidation levels. These data reveal new insights into the virus-host interactions between hnRNP A2 and the HIV-1 A2REs and their influence on the patterns of HIV-1 gene expression and viral assembly.

Animals↗
PubMed2004

The tyrosine-based YXXØ targeting motif of murine leukemia virus envelope glycoprotein affects pathogenesis.

Retroviruses, such as human and simian immunodeficiency viruses (HIV and SIV), and murine leukemia viruses (MuLV), harbor a tyrosine-based motif in the intracytoplasmic domain of their envelope glycoprotein. This motif can act as an endocytosis signal or as a targeting signal, restricting viral budding at specific cell surface membrane domains. In the present study, proviral DNA of the ecotropic Cas-Br-E strain of MuLV was modified by substitution or deletion of the critical tyrosine residue. Mutant viruses lost basolateral targeting in polarized MDCK epithelial cells while expression level of the glycoprotein at the cell surface was not affected. This suggests that the tyrosine-based motif in MuLV does not act as an endocytosis signal. Only a small delay in the appearance of disease was observed in inoculated mice. In contrast, a striking change in the pathology was observed with enlarged thymus and lymph nodes in animals inoculated with mutant viruses.

Amino Acid Motifs↗
PubMed2004

The Canadian study of the sirolimus-eluting stent in the treatment of patients with long de novo lesions in small native coronary arteries (C-SIRIUS).

OBJECTIVES: We assessed the safety and effectiveness of the sirolimus-eluting stent (SES) in treating single de novo long lesions in small native coronary arteries compared to an identical bare metal stent (BMS). BACKGROUND: The SES was previously demonstrated to reduce restenosis significantly. However, patients with long lesions in small vessels have not been well studied and may define a group at very high risk. METHODS: The Canadian Study of the Sirolimus-Eluting Stent in the Treatment of Patients With Long De Novo Lesions in Small Native Coronary Arteries (C-SIRIUS) was a multicenter, randomized, double-blind trial comparing SES versus identical BMS. The primary end point was in-stent minimal lumen diameter (MLD) at eight months. Secondary end points included angiographic restenosis at 8 months, target lesion revascularization (TLR), and major adverse cardiac events (MACE) at 270 days. RESULTS: A total of 100 patients were enrolled at eight Canadian sites. The in-stent MLD at eight months was 2.46 +/- 0.37 mm in the SES compared with 1.49 +/- 0.75 mm in the BMS (a 65% increase, p < 0.001). Angiographic restenosis occurred in 1 of 44 SES patients (2.3%, with no in-stent restenosis) and in 23 of 44 BMS patients (52.3%, p < 0.001). At 270 days, there were two clinically driven TLRs in the SES (4%) and nine in the BMS (18%, p = 0.05). The Kaplan-Meier estimate of freedom from MACE at 270 days was 96.0% for SES patients and 81.7% for BMS patients (p = 0.029). CONCLUSIONS: Patients with long lesions in small vessels are at very high risk of restenosis. In these patients, the SES dramatically reduces the risk of restenosis at eight months, translating into an excellent clinical outcome at nine months.

Angioplasty, Balloon, Coronary↗
PubMed2004

Triple antiplatelet therapy does not increase femoral access bleeding with vascular closure devices.

BACKGROUND: The use of arteriotomy closure devices (CDs) to achieve hemostasis after femoral artery access in percutaneous coronary intervention is steadily increasing. However, the safety information with these devices in the era of triple antiplatelet therapy is limited. METHODS: We reviewed prospectively collected data from the Do Tirofiban and ReoPro Give Similar Efficacy Outcomes Trial (TARGET), where all patients received aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitor therapy. At the treating physician's discretion, manual compression (MC) or a vascular hemostasis device was selected following femoral angiography. Patients receiving MC were to have sheaths removed 2 to 6 hours postprocedure when the activated clotting time was < or = 175 seconds. RESULTS: Of 4809 patients, 4736 had femoral access, and 985 of these had a CD (Perclose 47%, Angio-Seal 43%, VasoSeal 5%, and other 5%). The MC and CD groups were similar regarding most demographic characteristics, including age, systolic blood pressure, and weight, but those with MC were more often female, diabetic, and had history of peripheral vascular disease. Patients with a CD had a lower ischemic event rate suggesting they were a lower risk cohort overall. There were no differences in major bleeding at the access site (0.4% vs 0.5%, P =.588), minor bleeding at the access site (1.9% vs. 3.1%, P =.142) or transfusions (0.8% vs 1.0%, P =.513) between the MC and CD groups, respectively. CONCLUSIONS: In contemporary percutaneous coronary intervention practice, with appropriate patient selection, a CD can be safely utilized despite aggressive polypharmacy for procedural anticoagulation.

Angioplasty, Balloon, Coronary↗
PubMed2004

Pre-procedural plasma levels of C-reactive protein and interleukin-6 do not predict late coronary angiographic restenosis after elective stenting.

AIMS: Inflammatory markers may serve as an important prognostic predictor in patients with coronary heart diseases. In patients undergoing coronary interventions, it has been shown that baseline C-reactive protein (CRP) could predict late clinical restenosis. Only a few small studies have examined the possible relationship with angiographic restenosis. In patients with stable angina pectoris,we examined whether baseline CRP and IL-6 predict late coronary angiographic restenosis after stenting. METHODS AND RESULTS: Pre-procedural plasma levels of CRP and IL-6 were measured in 216 patients with stable angina pectoris undergoing elective coronary stenting. Angiographic follow-up was performed in all patients at 6 months. Baseline CRP levels were 6.15 +/- 0.78 mg/L versus 5.24 +/- 1.17 mg/L in the patent and restenosis groups, respectively (P=0.64). IL-6 levels were 0.46 +/- 0.03 ng/L versus 0.40 +/- 0.07 ng/L in the patent and restenosis groups, respectively (P=0.50). CRP levels were obtained again at the time of angiographic follow-up and were found to be similar in both groups (2.89 +/- 0.29 mg/L versus 2.61 +/- 0.63 mg/L, P=0.72). Moreover, in a sub-group of 43 patients, serial blood samples were obtained at several time points after the procedure up to 6 months. Both CRP and IL-6 plasma levels increased significantly in response to the procedure. CRP levels peaked at 3 days (11.27 +/- 1.53 mg/L versus 4.26 +/- 0.72 mg/L at baseline, P<0.0001). IL-6 levels reached maximum values after 24 h (1.08 +/- 0.14 ng/L versus 0.53 +/- 0.08 ng/L at baseline, P<0.0001). However, in this sub-group of patients, neither peak CRP nor IL-6 levels were found to predict late angiographic restenosis. CONCLUSIONS: Coronary stenting is associated with transient increases in both CRP and IL-6 levels. However, pre-procedural CRP and IL-6 levels do not predict late coronary angiographic restenosis.

Angina Pectoris↗
PubMed2004

Low rates of angiographic and clinical restenosis with the new flexible MedStent for the treatment of single discrete coronary lesions.

The use of enhanced designs of new coronary stents continues to expand the spectrum of coronary anatomy and clinical settings amenable to nonsurgical revascularization. The objectives of this clinical trial were to demonstrate the safety and late angiographic restenosis rate of the new flexible MedStent. The study included 117 patients with stable or unstable angina pectoris and a discrete de novo lesion of a native coronary artery. Procedural success, 6-month angiographic findings, and 1-year clinical outcomes were determined. The stent was successfully deployed in all but one patient (99.1%). There were no events in any of the patients within the first 2 weeks after the procedure. At 1 year, a total of 12 patients had 16 clinical events related to the stented artery (1 death, 3 non-Q-wave MIs, 10 repeat PTCAs, and 2 CABG procedures). This represents a target vessel revascularization rate (TVR) of 10.3%. The minimal luminal diameter (MLD) at 6 months for the MedStent was 2.04 +/- 0.71 mm. The 6-month binary angiographic restenosis was 20.0% (95% CI, 12.5%-27.5%). The results of the Medstent study in discrete, de novo native coronary lesions demonstrated low incidence of clinical events as well as favorable angiographic restenosis rate.

Coronary Angiography↗
PubMed2004

Assessment of the role of the central DNA flap in human immunodeficiency virus type 1 replication by using a single-cycle replication system.

In this study, reverse transcriptase (RT)- and integrase (IN)-defective human immunodeficiency virus type 1 (HIV-1) was transcomplemented with Vpr-RT-IN fusion proteins to delineate pol sequences important for HIV-1 replication. Our results reveal that a 194-bp sequence encompassing the 3'end of the IN gene and containing the central DNA flap is necessary and sufficient for efficient HIV-1 single-cycle replication in dividing and nondividing cells. Furthermore, we show that the central DNA flap enhances HIV-1 single-round replication by five- to sevenfold, primarily by facilitating nuclear import of proviral DNA. In agreement with previous reports, our data support a functional role of the central DNA flap during the early stages of HIV-1 infection.

Cell Nucleus↗
PubMed2004

Recent advances in the understanding of HIV-1 Vpu accessory protein functions.

HIV-1 encodes a number of accessory proteins, which are not commonly found in other retroviruses. These proteins, which include Vif, Vpr, Vpu and Nef, act as multifunctional adapters capable of recruiting and modulating basic host cell processes to optimize wide-ranging aspects of viral replication. This review describes our current understanding of how the Vpu accessory protein functions to modulate HIV-1 particle release and CD4 receptor expression during HIV-1 infection and underlines the potential opportunities afforded by this viral protein for therapeutic intervention.

Amino Acid Sequence↗
PubMed2004

Role of CD4 receptor down-regulation during HIV-1 infection.

Human immunodeficiency virus has evolved several redundant mechanisms to remove its receptor, the CD4 molecule, from the cell surface. Indeed, HIV-1 encodes three proteins, Nef, Vpu and Env, that have a profound effect on CD4 trafficking and catabolism. Given this functional convergence, it is believed that cell surface CD4 regulation constitutes an important determinant of viral replication and pathogenesis in vivo. This review highlights recent progress made in our understanding of the molecular mechanisms underlying the down-regulation of the CD4 receptor by HIV-1 and describes our current comprehension of the role of CD4 down-regulation during HIV-1 infection.

CD4 Antigens↗
PubMed2004

A comparison of clinical outcomes between Canadian and American patients after nonurgent coronary stenting.

BACKGROUND: Practice patterns for percutaneous coronary interventions (PCIs) may differ between Canada and the United States. Few data are available comparing PCI outcomes between the two countries in the era of coronary stenting and adjunctive glycoprotein IIb/IIIa inhibition. METHODS: In the Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial, 2064 patients were randomly assigned to receive eptifibatide or placebo during nonurgent PCI. The 30-day and one-year rates of death, myocardial infarction (MI) and target vessel revascularization (TVR) were compared between Canadian and American patients enrolled in the ESPRIT trial. RESULTS: There were 1531 American patients and 533 Canadian patients enrolled. Americans were older and heavier, and had a higher incidence of cardiac risk factors than Canadians (P<0.05 for all variables). Canadian patients had a lower incidence of death, MI and TVR at 30 days (6.2% versus 10.4%, P=0.004) and at one year (14.8% versus 21.5%, P=0.0006). After adjusting for known baseline differences, enrollment in Canada remained a significant predictor of reduced ischemic complications at 30 days (OR=0.53, c2=9.0, P=0.003). Similar results were observed at one year. Eptifibatide was superior to placebo in both groups of patients. CONCLUSIONS: This analysis is among the first to show Canadian patients to have fewer adverse events than American patients after nonurgent PCI. This effect was independent of known baseline differences between the patients in each country. The relative treatment effect of eptifibatide in Canadian patients paralleled that observed in the main ESPRIT trial and in American patients.

Aged↗
PubMed2004

High mortality with ST elevation myocardial infarction in a nontrial setting.

BACKGROUND: Early mortality following ST elevation myocardial infarction (MI) is declining in trial and nontrial settings. Absolute rates in nontrial settings remain significantly higher than those seen in randomized controlled trials. It is unclear if this mortality difference is due to different patient characteristics or to less frequent use of reperfusion strategies. OBJECTIVES: To provide a descriptive analysis of contemporary management and outcome of ST elevation MI in a nontrial setting at a tertiary care hospital, and to compare the clinical characteristics and in-hospital mortality of patients with ST elevation MI who were or were not treated with reperfusion therapy. METHODS: A retrospective chart review of 115 patients with ST elevation MI from July 1999 to June 2000 was performed. RESULTS: Eighty-five of 109 (78%) eligible patients received reperfusion therapy--44% fibrinolysis, 27% primary percutaneous coronary intervention (PCI) and 7% rescue PCI. Twenty-two per cent of eligible patients received no form of reperfusion therapy. In-hospital mortality was higher among patients who received no reperfusion therapy than among those who had (50% versus 11%, respectively, P<0.001). Patients who did not receive reperfusion therapy were older, presented with a longer median duration of chest pain, had a higher incidence of Killip class III or IV, and had a higher mean Thrombolysis in Myocardial Infarction (TIMI) risk score; many had absolute or relative contraindications to fibrinolytic therapy, and a significant proportion presented with a duration of chest pain of 12 h to 24 h. CONCLUSIONS: Mortality in ST elevation MI is disproportionately higher among patients who receive no reperfusion therapy. Many of these patients have clinical characteristics that may affect the physician's decision to provide reperfusion therapy. Improving overall survival among patients with ST elevation MI will be contingent on optimizing the number of patients receiving reperfusion therapy.

Age Factors↗
PubMed2003

Prospective, randomized evaluation of thrombectomy prior to percutaneous intervention in diseased saphenous vein grafts and thrombus-containing coronary arteries.

OBJECTIVES: We sought to determine whether routine thrombectomy prior to stent implantation in diseased saphenous vein grafts (SVGs) and thrombus-containing native coronary arteries would reduce peri-procedural myonecrosis and subsequently enhance event-free survival. BACKGROUND: Percutaneous coronary intervention in diseased SVGs and thrombotic native coronary arteries is complicated by a high rate of peri-procedural myocardial infarction (MI). Thrombectomy prior to intervention may enhance the safety of intervention and improve early and late outcomes in these high-risk patients. METHODS: At 60 centers in the U.S. and Canada, 797 patients with 839 diseased SVGs or thrombus-containing native coronary arteries were prospectively randomized to stent implantation with versus without prior thrombectomy with the X-SIZER device (ev3, Plymouth, Minnesota). RESULTS: Peri-procedural MI occurred in 15.8% of patients assigned to the X-SIZER device compared with 16.6% of control patients (p = 0.77), although the rate of large MI (pre-specified as the development of new pathologic Q waves or creatine phosphokinase-MB isoenzyme elevation >8 x upper limits of normal) was reduced with X-SIZER device use from 9.6% to 5.5% (multivariate risk ratio 0.35 [95% confidence interval 0.18 to 0.66], p = 0.002). Major adverse cardiac events (cardiac death, MI, or repeat target vessel revascularization) occurred in 16.8% of X-SIZER patients versus 17.1% of control patients at 30 days (p = 0.92), and in 31.3% of X-SIZER patients versus 28.2% of control patients at 1 year (p = 0.35). CONCLUSIONS: Thrombectomy with the X-SIZER device prior to stent implantation in high-risk diseased SVGs and thrombus-containing native coronary arteries may reduce the extent, but not the occurrence, of myonecrosis. Early and late event-free survival, however, were not improved by routine thrombectomy with this device.

Adult↗
PubMed2003

Vpu exerts a positive effect on HIV-1 infectivity by down-modulating CD4 receptor molecules at the surface of HIV-1-producing cells.

Human immunodeficiencey virus, type 1 (HIV-1) encodes three proteins, Nef, Vpu, and gp160, that down-modulate surface expression of the CD4 receptor during viral infection. In the present study, we have investigated the role of CD4 down-modulation in the HIV-1 infection cycle, primarily from the perspective of Vpu function. We report here that, like Nef, Vpu-mediated CD4 degradation modulates positively HIV-1 infectivity. Our data reveal that accumulation of CD4 at the cell surface of Vpu-deficient HIV-1-producing cells leads to an efficient recruitment of CD4 into virions and to an impairment of viral infectivity. This CD4-mediated inhibition of viral infectivity was not observed when a CD4 mutant unable to bind Env gp120 was used or when VSV-G glycoprotein was utilized to pseudotype viruses, suggesting that an interaction between CD4 and gp120 is required for interference. Indeed, protein analysis of Vpu-defective viral particles reveals that CD4 recruitment is associated with an increased formation of gp120-CD4 complexes at the virion surface. Interestingly, we did not detect any difference at the level of total virion-associated Env glycoproteins between wild-type and Vpu-defective virus, indicating that accumulation of CD4 at the cell surface and recruitment of CD4 into Vpu-defective HIV-1 particles exert a negative effect on viral infectivity, most likely by promoting the formation of nonfunctional gp120-CD4 complexes at the virion surface. Finally, we show that both Vpu- and Nef-induced CD4 down-modulation activities are required for production of fully infectious particles in CD4+ T cell lines and primary cells, an observation that has clear implications for viral spread in vivo.

Blotting, Western↗
PubMed2003

Bivalirudin and provisional glycoprotein IIb/IIIa blockade compared with heparin and planned glycoprotein IIb/IIIa blockade during percutaneous coronary intervention: REPLACE-2 randomized trial.

CONTEXT: The direct thrombin inhibitor bivalirudin has been associated with better efficacy and less bleeding than heparin during coronary balloon angioplasty but has not been widely tested during contemporary percutaneous coronary intervention (PCI). OBJECTIVE: To determine the efficacy of bivalirudin, with glycoprotein IIb/IIIa (Gp IIb/IIIa) inhibition on a provisional basis for complications during PCI, compared with heparin plus planned Gp IIb/IIIa blockade with regard to protection from periprocedural ischemic and hemorrhagic complications. DESIGN, SETTING, AND PARTICIPANTS: The Randomized Evaluation in PCI Linking Angiomax to Reduced Clinical Events (REPLACE)-2 trial, a randomized, double-blind, active-controlled trial conducted among 6010 patients undergoing urgent or elective PCI at 233 community or referral hospitals in 9 countries from October 2001 through August 2002. INTERVENTIONS: Patients were randomly assigned to receive intravenous bivalirudin (0.75-mg/kg bolus plus 1.75 mg/kg per hour for the duration of PCI), with provisional Gp IIb/IIIa inhibition (n = 2999), or heparin (65-U/kg bolus) with planned Gp IIb/IIIa inhibition (abciximab or eptifibatide) (n = 3011). Both groups received daily aspirin and a thienopyridine for at least 30 days after PCI. MAIN OUTCOME MEASURES: The primary composite end point was 30-day incidence of death, myocardial infarction, urgent repeat revascularization, or in-hospital major bleeding; the secondary composite end point was 30-day incidence of death, myocardial infarction, or urgent repeat revascularization. RESULTS: Provisional Gp IIb/IIIa blockade was administered to 7.2% of patients in the bivalirudin group. By 30 days, the primary composite end point had occurred among 9.2% of patients in the bivalirudin group vs 10.0% of patients in the heparin-plus-Gp IIb/IIIa group (odds ratio, 0.92; 95% confidence interval, 0.77-1.09; P =.32). The secondary composite end point occurred in 7.6% of patients in the bivalirudin vs 7.1% of patients in the heparin-plus-Gp IIb/IIIa groups (odds ratio, 1.09; 95% confidence interval 0.90-1.32; P =.40). Prespecified statistical criteria for noninferiority to heparin plus Gp IIb/IIIa were satisfied for both end points. In-hospital major bleeding rates were significantly reduced by bivalirudin (2.4% vs 4.1%; P<.001). CONCLUSIONS: Bivalirudin with provisional Gp IIb/IIIa blockade is statistically not inferior to heparin plus planned Gp IIb/IIIa blockade during contemporary PCI with regard to suppression of acute ischemic end points and is associated with less bleeding.

Abciximab↗
PubMed2003

Two-step purification of His-tagged Nef protein in native condition using heparin and immobilized metal ion affinity chromatographies.

The Nef protein encoded by human immunodeficiency virus type 1 (HIV-1) has been shown to be an important factor of progression of viral growth and pathogenesis in both in vitro and in vivo. The lack of a simple procedure to purify Nef in its native conformation has limited molecular studies on Nef function. A two-step procedure that includes heparin and immobilized metal ion affinity chromatographies (IMACs) was developed to purify His-tagged Nef (His(6)-Nef) expressed in bacteria in native condition. During the elaboration of this purification procedure, we identified two closely SDS-PAGE-migrating contaminating bacterial proteins, SlyD and GCHI, that co-eluted with His(6)-Nef in IMAC in denaturing condition and developed purification steps to eliminate these contaminants in native condition. Overall, this study describes a protocol that allows rapid purification of His(6)-Nef protein expressed in bacteria in native condition and that removes metal affinity resin-binding bacterial proteins that can contaminate recombinant His-tagged protein preparation.

Chromatography, Affinity↗
PubMed2003

Ethics and equipoise: rationale for a placebo-controlled study design of platelet glycoprotein IIb/IIIa inhibition in coronary intervention.

Rarely is it straightforward to specify the design and parameters of a clinical trial investigating an alternative therapy where effective therapies already exist. If existing therapeutic interventions are highly efficacious, safe, inexpensive, and firmly entrenched, an active-control design becomes the logical first choice. Short of this absolute condition, however, the merits and realities of the scientific, clinical, corporate, and regulatory environments need to be weighed before determining the appropriate approach. A state of clinical equipoise with regard to the use of glycoprotein (GP) IIb/IIIa therapy in percutaneous coronary intervention (PCI) provided the unique opportunity to address the complexities in selecting a placebo-controlled design for the Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Trial (ESPRIT). ESPRIT investigators assessed whether a high dose of eptifibatide would improve the outcomes of patients undergoing coronary stenting. By using the example of the ESPRIT trial, we examine factors warranting the need for this trial and evaluate the process whereby the United States Food and Drug Administration (FDA) gave approval for a placebo-controlled design. Although the focus of this trial is GP IIb/IIIa inhibition therapy, the issues pertaining to the trial and how they were resolved are general enough to be applied to the design and conduct of clinical trials across a broad spectrum of illnesses and therapeutic modalities.

Angioplasty, Balloon, Coronary↗