Retrospective study of the impact of fellowship training on two quality and safety measures in uterine artery embolization.

RATIONALE AND OBJECTIVES: To measure the impact of 1-year interventional fellowship training on fluoroscopic time and contrast media utilization in uterine artery embolization (UAE). MATERIALS AND METHODS: Retrospective single institution analysis of 323 consecutive UAEs performed by 12 interventional fellows using a standardized protocol. Fluoroscopy time and contrast media volume were recorded for each patient and correlated with stage of fellowship training. Preprocedure uterine volume (using MRI or ultrasound) was used as a measure of procedural complexity. Regression analysis was conducted per trainee factoring in duration of training, procedure number, supervising radiologist, uterine volume, and outcome variables of fluoroscopy time and contrast media volume. RESULTS: Median number of patients treated per trainee was 27 (range, 16-43) with mean fluoroscopic time 24.5 minutes (range, 4-90 min) and mean contrast volume 190 mL (range, 50-320 mL). Increasing uterine volume had no significant effect (P > .05) on fluoroscopic time but significantly increased (P < .001) contrast media volume. Significant training effect was identified with decrease in fluoroscopic time (P < .001) and decrease in contrast volume (P = .02) over training. Over the course of a 1-year fellowship, these summed to a decrease of 12 minutes in UAE fluoroscopy time and 17 mL less contrast. CONCLUSION: A significant (P < .05) training effect that is clinically relevant was demonstrated over the course of a yearlong interventional radiology fellowship program in performance of a standardized protocol for UAE. This data supports fellowship training as a basis for UAE credentialing and privileging.

Upregulation and expression patterns of the angiogenic transcription factor ets-1 in Alzheimer's disease brain.

Immunohistochemical staining has been used to determine expression patterns of the angiogenic transcription factor, Ets-1, in the brains of Alzheimer's disease (AD) individuals. Brain tissue from non-demented controls showed little expression of Ets-1 whereas in AD brain tissue, Ets-1 was ubiquitously expressed in cortex and hippocampus. Double immunostaining with von Willerbrand factor demonstrated prominent Ets-1 intravascular immunoreactivity (ir) in AD cortical microvessels. In addition, Ets-1 also exhibited extravascular expression characterized by a diffuse pattern of Ets-1 ir in AD brain. Double staining also showed Ets-1 colocalization in microvasculature with the potent angiogenic agent, vascular endothelial growth factor (VEGF). Cell-associated tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine with pro-angiogenic activity, was primarily associated with diffuse extravascular Ets-1 ir. Clusters of HLA-DR positive microglia, resident immune cells of brain which release TNF-α, were also localized with diffuse Ets-1. Intravascular Ets-1 ir was maximally co-localized with soluble amyloid-ß peptide (Aß), Aß1-40, in microvasculature whereas diffuse extravascular Ets-1 ir appeared in proximity to Aß plaques in brain parenchyma. Similar overall results were obtained for patterns of Ets-1 staining in AD hippocampal tissue. This work provides novel findings on expression of the angiogenic transcription factor, Ets-1, in vascular remodeling and its association with pro-angiogenic factors, reactive microglia, and Aß deposition in AD brain.

A fluorescence resonance energy transfer-based binding assay for characterizing kinase inhibitors: important role for C-terminal biotin tagging of the kinase.

Novel biochemical strategies are needed to identify the next generation of protein kinase inhibitors. One promising new assay format is a competition binding approach that employs time-resolved fluorescence resonance energy transfer (TR-FRET). In this assay, a FRET donor is bound to the kinase via a purification tag, whereas a FRET acceptor is bound via a tracer-labeled inhibitor. Displacement of the tracer by an unlabeled inhibitor eliminates FRET between the fluorophores and provides a readout on binding. Although promising, this technique has so far been limited in applicability in part by a lack of signal strength is some cases and also by an inability to predict whether a particular tagging strategy will show robust FRET. In this work, we sought to better understand the factors that give rise to a strong FRET signal in this assay. We determined the magnitude of FRET for several tyrosine kinases using different purification tags (biotin, glutathione S-transferase [GST], and His) placed at either the N terminus or C terminus of the kinase. It was observed that coupling the FRET acceptor to the kinase C terminus using a biotin/streptavidin interaction resulted in the greatest increase in FRET. Specifically, for multiple kinases, the signal/background ratio was at least 3-fold better using C-terminal biotinylation compared with tagging at the N terminus using a His/anti-His antibody or GST/anti-GST antibody interaction. In one case, the FRET signal using C-terminal biotin tagging was more than 150-fold over background. This strong FRET signal facilitated development of improved inhibitor binding assays that required only tens of picomolar enzyme or tracer-labeled inhibitor. Together, these results indicate that C-terminal biotinylation is a promising tagging strategy for developing an optimal FRET-based competition binding assay for tyrosine kinases.