Combinatorial mRNA binding by AUF1 and Argonaute 2 controls decay of selected target mRNAs.

The RNA-binding protein AUF1 binds AU-rich elements in 3'-untranslated regions to regulate mRNA degradation and/or translation. Many of these mRNAs are predicted microRNA targets as well. An emerging theme in post-transcriptional control of gene expression is that RNA-binding proteins and microRNAs co-regulate mRNAs. Recent experiments and bioinformatic analyses suggest this type of co-regulation may be widespread across the transcriptome. Here, we identified mRNA targets of AUF1 from a complex pool of cellular mRNAs and examined a subset of these mRNAs to explore the links between RNA binding and mRNA degradation for both AUF1 and Argonaute 2 (AGO2), which is an essential effector of microRNA-induced gene silencing. Depending on the specific mRNA examined, AUF1 and AGO2 binding is proportional/cooperative, reciprocal/competitive or independent. For most mRNAs in which AUF1 affects their decay rates, mRNA degradation requires AGO2. Thus, AUF1 and AGO2 present mRNA-specific allosteric binding relationships for co-regulation of mRNA degradation.

Using texture analyses of contrast enhanced CT to assess hepatic fibrosis.

PURPOSE: To determine the ability of texture analyses of contrast-enhanced CT images for distinguishing between varying degrees of hepatic fibrosis in patients with chronic liver disease using histopathology as the reference standard. MATERIALS AND METHODS: Following IRB approval, 83 patients who underwent contrast enhanced 64-MDCT of the abdomen and pelvis in the portal venous phase between 12/2005 and 01/2013 and who had a liver biopsy within 6 months of the CT were included. An in-house developed, MATLAB-based texture analysis program was employed to extract 41 texture features from each of 5 axial segmented volumes of liver. Using the Ishak fibrosis staging scale, histopathologic grades of hepatic fibrosis were correlated with texture parameters after stratifying patients into three analysis groups, comparing Ishak scales 0-2 with 3-6, 0-3 with 4-6, and 0-4 with 5-6. To assess the utility of texture features, receiver operating characteristic (ROC) curves were constructed and the area under the curve (AUC) was used to determine the performance of each feature in distinguishing between normal/low and higher grades of hepatic fibrosis. RESULTS: A total of 19 different texture features with 7 histogram features, one grey level co-occurrence matrix, 6 gray level run length, 1 Laws feature, and 4 gray level gradient matrix demonstrated statistically significant differences for discriminating between fibrosis groupings. The highest AUC values fell in the range of fair performance for distinguishing between different fibrosis groupings. CONCLUSION: These findings suggest that texture-based analyses of contrast-enhanced CT images offer a potential avenue toward the non-invasive assessment of liver fibrosis.

Leadership training for radiologists: a survey of opportunities and participants in MBA and MPH programs by medical students, residents, and current chairpersons.

PURPOSE: The aim of this study was to determine opportunities for students and trainees to obtain an MPH or MBA degree during either medical school or radiology residency and to determine the prevalence of such degree possession by chairpersons in radiology. METHODS: All allopathic medical schools in the United States were surveyed to chart the number of MD/MPH and MD/MBA degree programs available to students. Program directors were contacted to assess the number of MPH or MBA courses of study administratively related to their residencies. Also, an e-mail survey was sent to all members of the Society of Chairs of Academic Radiology Departments inquiring whether each chairperson had earned an additional degree. RESULTS: Currently, 81 allopathic medical schools in the United States offer MD/MPH degrees, and 52 offer MD/MBA degrees. Six residencies provide access to MPH programs, and 3 residencies provide the opportunity to pursue an MBA in conjunction with residency. Of these, only 1 MPH program and no MBA programs had trainees enrolled at present. Twenty-six percent of the chairpersons surveyed possessed advanced degrees other than MDs. CONCLUSION: There has been rapid growth in the number of MD/MPH and MD/MBA programs available to medical students. However, there is a scarcity of similar programs accessible to trainees during or just after residency training. To assist motivated radiologists interested in leading our profession, opportunities should expand both in formal degree-granting programs and through certificate-sanctioned course series to address relevant issues of leadership and management pertinent to our specialty.