Potential Use of Quantum Dots in Flow Cytometry

QDs may offer significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We have examined the possible applications of QDs for flow cytometric measurements (FCM) by studying their excitation - emission spectra and their binding to paramagnetic beads. We labelled beads with either QDs or a commonly-used fluorochrome (FITC) and studied their fluorescence intensity by FCM. Flow cytometric comparisons indicated that the minimum fluorophore concentration required for detection of QDs above autofluorescent background was 100-fold less than for FITC

Ramipril After Transcatheter Aortic Valve Implantation in Patients Without Reduced Ejection Fraction: The RASTAVI Randomized Clinical Trial

Background: Patients with aortic stenosis may continue to have an increased risk of heart failure, arrhythmias, and death after successful transcatheter aortic valve implantation. Renin-angiotensin system inhibitors may be beneficial in this setting. We aimed to explore whether ramipril improves the outcomes of patients with aortic stenosis after transcatheter aortic valve implantation. Methods and Results: PROBE (Prospective Randomized Open, Blinded Endpoint) was a multicenter trial comparing ramipril with standard care (control) following successful transcatheter aortic valve implantation in patients with left ventricular ejection fraction >40%. The primary end point was the composite of cardiac mortality, heart failure readmission, and stroke at 1-year follow-up. Secondary end points included left ventricular remodeling and fibrosis. A total of 186 patients with median age 83 years (range 79-86), 58.1% women, and EuroSCORE-II 3.75% (range 3.08-4.97) were randomized to receive either ramipril (n=94) or standard treatment (n=92). There were no significant baseline, procedural, or in-hospital differences. The primary end point occurred in 10.6% in the ramipril group versus 12% in the control group (P=0.776), with no differences in cardiac mortality (ramipril 1.1% versus control group 2.2%, P=0.619) but lower rate of heart failure readmissions in the ramipril group (3.2% versus 10.9%, P=0.040). Cardiac magnetic resonance analysis demonstrated better remodeling in the ramipril compared with the control group, with greater reduction in end-systolic and end-diastolic left ventricular volumes, but nonsignificant differences were found in the percentage of myocardial fibrosis. Conclusions: Ramipril administration after transcatheter aortic valve implantation in patients with preserved left ventricular function did not meet the primary end point but was associated with a reduction in heart failure re-admissions at 1-year follow-up

Detection of environmental microorganisms with a bead-based assay and quantum dots

Quantum dots (QDs) promise significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We examined the possible applications of QDs as markers for flow cytometric measurements. Paramagnetic beads were labelled with either QDs or some commonly-used fluorochromes and their fluorescence intensity was studied by flow cytometry after DNA capture or amplification. PCR amplicons were detected successfully when using a blue light excitation source for the QDs. Despite the low fluorescent signal of QDs compared to organic dyes found in this study, it is anticipated that the use of a UV laser instead of a blue laser would magnify the signal intensity significantly. We describe a bead-based method for identifying bacteria and archaea based on beads with an inherent fluorescent dye but applications of QDs may be reduced due to their large size relative to current fluorophores.21 page(s

New strategies for the detection of pathogens from industrial wastewater samples

As increasing water shortages continue, water re-use is posing new challenges with treated wastewater becoming a significant source of non-potable water. Rapid detection strategies that target waterborne pathogens of concern to industry are gaining importance in the assessment of water quality. Recent government initiatives recognise the need for change, with regulations now aimed at reducing water consumption per person while increasing the reuse or recycling of wastewater (Anonymous, 2003; Anonymous, 2004). However, the safe management of recycled or re-use water is a pressing concern for non-traditional sources to be acceptable by the community.6 page(s