Prehospital fibrinolysis with timely coronary angiography resulted in effective reperfusion in patients with early STEMI who could not undergo primary PCI within 1 hour after the first medical contact. However, fibrinolysis was associated with a slightly increased risk of intracranial bleeding. (Funded by Boehringer Ingelheim; ClinicalTrials.gov number, NCT00623623.).
In order to investigate the relationship between lipid structure and liposome-mediated gene transfer, we have studied biophysical parameters and transfection properties of monocationic DOTAP analogs, systematically modified in their non-polar hydrocarbon chains. Stability, size and (by means of anisotropy profiles) membrane fluidity of liposomes and lipoplexes were determined, and lipofection efficiency was tested in a luciferase reporter gene assay. DOTAP analogs were used as single components or combined with a helper lipid, either DOPE or cholesterol. Stability of liposomes was a precondition for formation of temporarily stable lipoplexes. Addition of DOPE or cholesterol improved liposome and lipoplex stability. Transfection efficiencies of lipoplexes based on pure DOTAP analogs could be correlated with stability data and membrane fluidity at transfection temperature. Inclusion of DOPE led to rather uniform transfection and anisotropy profiles, corresponding to lipoplex stability. Cholesterol-containing lipoplexes were generally stable, showing high transfection efficiency at low relative fluidity. Our results demonstrate that the efficiency of gene transfer mediated by monocationic lipids is greatly influenced by lipoplex biophysics due to lipid composition. The measurement of fluorescence anisotropy is an appropriate method to characterize membrane fluidity within a defined system of liposomes or lipoplexes and may be helpful to elucidate structure-activity relationships.
G uidelines recommend a primary percutaneous coronary intervention (pPCI) as the preferred reperfusion modality in patients presenting with ST-segment-elevation myocardial infarction (STEMI).1,2 Because most STEMI patients initially present to hospitals without PCI facilities, performing a pPCI in a timely fashion constitutes a significant logistic challenge in many healthcare systems across the world. Despite Background-In the Strategic Reperfusion Early After Myocardial Infarction (STREAM) trial, a pharmaco-invasive (PI) strategy was compared with primary percutaneous coronary intervention (pPCI) in ST-segment-elevation myocardial infarction patients presenting within 3 hours after symptom onset but unable to undergo pPCI within 1 hour. At 30 days, the PI approach was associated with a nominally but nonstatistically significant lower incidence of the composite primary end point of death, shock, congestive heart failure, and reinfarction when compared with pPCI. The aim of the present study was to determine the effect of these strategies on 1-year mortality. Methods and Results-Vital status at 1 year was available in 936 of 944 (99.2%) and 941 of 948 (99.3%) patients in the PI and pPCI arm, respectively. At 1 year, all-cause mortality rates (6.7% versus 5.9%) were similar for PI and pPCItreated patients (P=0.49; risk ratio, 1.13; 95% confidence interval, 0.79-1.62). Cardiac mortality rates were similar as well (4.0% versus 4.1%, P=0.93; risk ratio, 0.98; 95% confidence interval, 0.62-1.54). Overall, only 34 patients died between day 30 and 1 year, 20 in the PI arm and 14 in the pPCI arm, of whom 20 died of noncardiac reasons (13 in the PI and 7 in the pPCI arm). There was no significant difference in 1-year all-cause mortality between the 2 groups among the prespecified key subgroups. Conclusions-At 1 year, mortality rates in the PI and pPCI arms were similar in ST-segment-elevation myocardial infarction patients presenting within 3 hours after symptom onset and unable to undergo pPCI within 1 hour. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00623623.
Lipofection, the transfer of genetic material into cells by means of cationic lipids, is of growing interest for in vitro and in vivo approaches. In order to identify ideal lipofection reagents in a HTS, we have developed an automated lipofection method for the transfer of reporter genes into cells and for determination of the lipofection results. The method has specifically been designed and optimized for 96-well microtiter plates and can successfully be carried out by a pipetting robot with accessory equipment. It consists of two separate parts: (1) pretransfection (preparation of liposomes, formation of lipoplexes, and lipoplex transfer to the cells) and (2) posttransfection (determination of the reporter enzyme activity and the protein content of the transfected cells). Individual steps of the lipofection method were specifically optimized - for example, lipoplex formation and incubation time as well as cell lysis, cell cultivating, and the reporter gene assay. The HTS method facilitates characterization of the transfection properties (efficiency and cytotoxicity) of large numbers of (cationic) lipids in various adherent cell types.
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