Signaling local non-credibility in an automatic segmentation pipeline

The advancing technology for automatic segmentation of medical images should be accompanied by techniques to inform the user of the local credibility of results. To the extent that this technology produces clinically acceptable segmentations for a significant fraction of cases, there is a risk that the clinician will assume every result is acceptable. In the less frequent case where segmentation fails, we are concerned that unless the user is alerted by the computer, she would still put the result to clinical use. By alerting the user to the location of a likely segmentation failure, we allow her to apply limited validation and editing resources where they are most needed. We propose an automated method to signal suspected non-credible regions of the segmentation, triggered by statistical outliers of the local image match function. We apply this test to m-rep segmentations of the bladder and prostate in CT images using a local image match computed by PCA on regional intensity quantile functions. We validate these results by correlating the non-credible regions with regions that have surface distance greater than 5.5mm to a reference segmentation for the bladder. A 6mm surface distance was used to validate the prostate results. Varying the outlier threshold level produced a receiver operating characteristic with area under the curve of 0.89 for the bladder and 0.92 for the prostate. Based on this preliminary result, our method has been able to predict local segmentation failures and shows potential for validation in an automatic segmentation pipeline

Reliability and Validity of the Telephone-Based eHealth Literacy Scale Among Older Adults: Cross-Sectional Survey

Background: Only a handful of studies have examined reliability and validity evidence of scores produced by the 8-item eHealth literacy Scale (eHEALS) among older adults. Older adults are generally more comfortable responding to survey items when asked by a real person rather than by completing self-administered paper-and-pencil or online questionnaires. However, no studies have explored the psychometrics of this scale when administered to older adults over the telephone. Objective: The objective of our study was to examine the reliability and internal structure of eHEALS data collected from older adults aged 50 years or older responding to items over the telephone. Methods: Respondents (N=283) completed eHEALS as part of a cross-sectional landline telephone survey. Exploratory structural equation modeling (E-SEM) analyses examined model fit of eHEALS scores with 1-, 2-, and 3-factor structures. Subsequent analyses based on the partial credit model explored the internal structure of eHEALS data. Results: Compared with 1- and 2-factor models, the 3-factor eHEALS structure showed the best global E-SEM model fit indices (root mean square error of approximation=.07; comparative fit index=1.0; Tucker-Lewis index=1.0). Nonetheless, the 3 factors were highly correlated (r range .36 to .65). Item analyses revealed that eHEALS items 2 through 5 were overfit to a minor degree (mean square infit/outfit values <1.0; t statistics less than –2.0), but the internal structure of Likert scale response options functioned as expected. Overfitting eHEALS items (2-5) displayed a similar degree of information for respondents at similar points on the latent continuum. Test information curves suggested that eHEALS may capture more information about older adults at the higher end of the latent continuum (ie, those with high eHealth literacy) than at the lower end of the continuum (ie, those with low eHealth literacy). Item reliability (value=.92) and item separation (value=11.31) estimates indicated that eHEALS responses were reliable and stable. Conclusions: Results support administering eHEALS over the telephone when surveying older adults regarding their use of the Internet for health information. eHEALS scores best captured 3 factors (or subscales) to measure eHealth literacy in older adults; however, statistically significant correlations between these 3 factors suggest an overarching unidimensional structure with 3 underlying dimensions. As older adults continue to use the Internet more frequently to find and evaluate health information, it will be important to consider modifying the original eHEALS to adequately measure societal shifts in online health information seeking among aging populations.Open Access Fundin

Does Gender Minority Professional Experience Impact Employment Discrimination? Two Résumé Experiments

We sought to examine perceived gender identity, perceived co-worker discomfort, and salary recommendations for youth counselors with transgender-related work experience. In two experiments conducted in 2016 and 2017, we randomized participants to view 1 of 2 résumés with varying work experience at a camp for transgender youth or a generic youth camp. Study 1 participants were 274 adult festivalgoers at a lesbian, gay, bisexual, and transgender pride festival. Study 2 participants were 296 employed, heterosexual adults aged 35-60 from an online survey panel. In Study 1, viewing the résumé with transgender experience resulted in a statistically significantly higher likelihood of reporting the applicant was gender minority than cisgender (adjusted odds ratio = 3.76, 95% confidence interval [1.32, 10.72],   p = .01), higher but not a statistically significant level of co-worker discomfort (aOR = 1.39, 95% CI [0.83, 2.32], p = .22), and, although not statistically significant, a $2,605 higher salary (95$604, - $5,814], p = .11). In Study 2, we found a statistically significantly greater likelihood of reporting the applicant was gender minority than cisgender (OR = 2.56, 95$1,374 higher salary (95% CI [-$1,931,$4,679], p = .41). Our results indicate the potential for stigma by association for professionals working with marginalized groups and suggest potential pathways through which employment discrimination may exacerbate existing inequities for gender minority people

Spatiotemporal regulation of ATP and Ca2+ dynamics in vertebrate rod and cone ribbon synapses

PurposeIn conventional neurons, Ca2+ enters presynaptic terminals during an action potential and its increased local concentration triggers transient exocytosis. In contrast, vertebrate photoreceptors are nonspiking neurons that maintain sustained depolarization and neurotransmitter release from ribbon synapses in darkness and produce light-dependent graded hyperpolarizing responses. Rods transmit single photon responses with high fidelity, whereas cones are less sensitive and exhibit faster response kinetics. These differences are likely due to variations in presynaptic Ca2+ dynamics. Metabolic coupling and cross-talk between mitochondria, endoplasmic reticulum (ER), plasma membrane Ca2+ ATPase (PMCA), and Na+-Ca2+ exchanger (NCX) coordinately control presynaptic ATP production and Ca2+ dynamics. The goal of our structural and functional studies was to determine the spatiotemporal regulation of ATP and Ca2+ dynamics in rod spherules and cone pedicles.MethodsCentral retina tissue from C57BL/6 mice was used. Laser scanning confocal microscopy (LSCM) experiments were conducted on fixed-frozen vertical sections. Primary antibodies were selected for their tissue/cellular specificity and ability to recognize single, multiple or all splice variants of selected isoforms. Electron microscopy (EM) and 3-D electron tomography (ET) studies used our standard procedures on thin- and thick-sectioned retinas, respectively. Calibrated fluo-3-Ca2+ imaging experiments of dark- and light-adapted rod and cone terminals in retinal slices were conducted.ResultsConfocal microscopy showed that mitochondria, ER, PMCA, and NCX1 exhibited distinct retinal lamination patterns and differential distribution in photoreceptor synapses. Antibodies for three distinct mitochondrial compartments differentially labeled retinal areas with high metabolic demand: rod and cone inner segments, previously undescribed cone juxtanuclear mitochondria and the two plexiform layers. Rod spherule membranes uniformly and intensely stained for PMCA, whereas the larger cone pedicles preferentially stained for NCX1 at their active zones and PMCA near their mitochondria. EM and ET revealed that mitochondria in rod spherules and cone pedicles differed markedly in their number, location, size, volume, and total cristae surface area, and cristae junction diameter. Rod spherules had one large ovoid mitochondrion located near its active zone, whereas cone pedicles averaged five medium-sized mitochondria clustered far from their active zones. Most spherules had one ribbon synapse, whereas pedicles contained numerous ribbon synapses. Fluo-3 imaging studies revealed that during darkness rod spherules maintained a lower [Ca2+] than cone pedicles, whereas during light adaptation pedicles rapidly lowered their [Ca2+] below that observed in spherules.ConclusionsThese findings indicate that ATP demand and mitochondrial ATP production are greater in cone pedicles than rod spherules. Rod spherules employ high affinity/low turnover PMCA and their mitochondrion to maintain a relatively low [Ca2+] in darkness, which increases their sensitivity and signal-to-noise ratio. In contrast, cone pedicles utilize low affinity/high turnover NCX to rapidly lower their high [Ca2+] during light adaptation, which increases their response kinetics. Spatiotemporal fluo-3-Ca2+ imaging results support our immunocytochemical results. The clustering of cone pedicle mitochondria likely provides increased protection from Ca2+ overload and permeability transition. In summary, these novel studies reveal that several integrated cellular and subcellular components interact to regulate ATP and Ca2+ dynamics in rod and cone synaptic terminals. These results should provide a greater understanding of in vivo photoreceptor synaptic terminal exocytosis/endocytosis, Ca2+ overload and therapies for retinal degenerations

The Otterbein Miscellany - May 1971

https://digitalcommons.otterbein.edu/miscellany/1000/thumbnail.jp

Vancomycin Dosing Practices among Critical Care Pharmacists: A Survey of Society of Critical Care Medicine Pharmacists

Introduction: Critically ill patients and their pharmacokinetics present complexities often not considered by consensus guidelines from the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Diseases Pharmacists. Prior surveys have suggested discordance between certain guideline recommendations and reported infectious disease pharmacist practice. Vancomycin dosing practices, including institutional considerations, have not previously been well described in the critically ill patient population. Objectives: To evaluate critical care pharmacists\u27 self-reported vancomycin practices in comparison to the 2009 guideline recommendations and other best practices identified by the study investigators. Methods: An online survey developed by the Research and Scholarship Committee of the Clinical Pharmacy and Pharmacology (CPP) Section of the Society of Critical Care Medicine (SCCM) was sent to pharmacist members of the SCCM CPP Section practicing in adult intensive care units in the spring of 2017. This survey queried pharmacists\u27 self-reported practices regarding vancomycin dosing and monitoring in critically ill adults. Results: Three-hundred and sixty-four responses were received for an estimated response rate of 26%. Critical care pharmacists self-reported largely following the 2009 vancomycin dosing and monitoring guidelines. The largest deviations in guideline recommendation compliance involve consistent use of a loading dose, dosing weight in obese patients, and quality improvement efforts related to systematically monitoring vancomycin-associated nephrotoxicity. Variation exists regarding pharmacist protocols and other practices of vancomycin use in critically ill patients. Conclusion: Among critical care pharmacists, reported vancomycin practices are largely consistent with the 2009 guideline recommendations. Variations in vancomycin dosing and monitoring protocols are identified, and rationale for guideline non-adherence with loading doses elucidated

Structure and mechanism of human DNA polymerase η

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase eta (Pol eta), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol eta at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol eta acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol eta orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol eta missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol eta in replicating through D loop and DNA fragile sites

A primer on quality indicators of distance education. Accepted for publication in Health Promotion Practice

Abstract: In the past decade, there has been an enormous growth of distance education courses and programs in higher education. The growth of distance education is particularly evident in the field of health education. However, the enormous potential of distance education is tempered by one overriding question: How does one ensure that distance education coursework and degrees are of high quality? To this end, the purpose of this study is twofold: to identify quality indicators of distance education and to provide implications of the identified quality indicators for health education researchers and practitioners. The results of the study reveal common benchmarks and quality indicators that all parties deem important in designing, implementing, and evaluating distance education courses and programs. Keywords: quality; quality indicators; distance education; health education; health promotion Article: In the past decade, there has been an enormous growth of distance education courses and programs in higher education Additionally, the American Association for Health Education, in concert with the Foundation for the Advancement of Health Education, is offering graduate-level courses in health education through distance education technology by partnering with university and instructional technology businesses (see www.hepnetwork .org). There are several reasons for this increased interest in distance education in higher education. Distance education programs: allow students easy access to courses, which has the potential to decrease time to graduation; provide opportunities for increased diversity and inter-nationalization in terms of attracting students from different parts of the country and world because they can access the materials for the course from anywhere; ease built environment constraints because classroom space is not needed in a distance education course; create a new market of time-and location-bound students; and increase revenue generation for the university or college. Questions, concerns, and opinions in academia regarding distance education and related instructional technology are emerging in the professional literature. Academic administrators and professors are seeking answers to questions about distance education, including how to determine quality. According to The issues surrounding quality of distance education have been discussed by stakeholders, including the federal government, state governments, accrediting associations, faculty, and even students BACKGROUND AND METHODS To generate a comprehensive list of quality indicators, a search of 10 electronic databases was conducted. The databases included EBSCO, ERIC, PsychINFO, Ovid, Gale, Medline, PubMed, Wilson, Cambridge, and CSA. Search engines such as Google Scholar were also used to identify distance education journal Web sites (e.g., American Journal of Distance Education) to access more articles and studies. Additionally, the resources available in Texas A&amp;M University libraries (e.g., books, dissertations, conferences, bulletins) were accessed to gather information on quality indicators of distance education. Key terms that were used to identify relevant studies were distance education, quality indicators, quality of distance education, Web-based courses, quality Web-based programs, quality instructional technology, quality distance courses, and literature review. Every paper that was identified through this process was taken into consideration, regardless of the year of publication. The references of these initial papers were searched for more studies that could be included in the review