Prevalence and risk factors of voice disorder symptoms in university professors: A pilot study in Nebraska

Although many studies note positive correlations between teaching professionals and voice disorder development, much of what is known is based on reports of elementary and secondary educators, not university professors. Few studies have sought to determine voice disorder prevalence and risk for university professors even though, as professional voice users, they are likely at high risk for voice disorder development. In the present study, 408 university professors responded to questions regarding general health, voice symptomology, and engagement in behaviors associated with voice quality and health. Almost 18% of respondents reported at least 1 consistent voice disorder symptom. Of these, hoarseness was the most commonly-reported symptom. Statistically significant differences between those reporting consistent symptomology and those who did not included feelings of stress/anxiety, medicine intake, and self-reported overall general health. Findings indicate the need for expanded study of this at-risk population and investigation into their access to voice-education and intervention resources

Can Nitrogen-13 Ammonia Kinetic Modeling Define Myocardial Viability Independent of Fluorine-18 Fluorodeoxyglucose?

AbstractObjectives. The hypothesis of this study was that evaluation of myocardial flow and metabolism using nitrogen-13 (N-13) ammonia kinetic modeling with dynamic positron emission tomographic (PET) imaging could identify regions of myocardial scar and viable myocardium as defined by fluorine-18 fluorodeoxyglucose (F-18 FDG) PET.Background. Uptake of most perfusion tracers depends on both perfusion and metabolic retention in tissue. This characteristic has limited their ability to differentiate myocardial scar from viable tissue. The kinetic modeling of N-13 ammonia permits quantification of blood flow and separation of the metabolic component of its uptake, which may permit differentiation of scar from viable tissue.Methods. Sixteen patients, >3 months after myocardial infarction, underwent dynamic N-13 ammonia and F-18 FDG PET imaging. Regions of reduced and normal perfusion were defined on static N-13 ammonia images. Patients were classified into two groups (group I [ischemic viable], n = 6; group II [scar], n = 10) on the basis of percent of maximal F-18 FDG uptake in hypoperfused segments. Nitrogen-13 ammonia kinetic modeling was applied to dynamic PET data, and rate constants were determined. Flow was defined by K1; volume of distribution (VD = K1/k2) of N-13 ammonia was used as an indirect indication of metabolic retention.Results. Fluorine-18 FDG uptake was reduced in patients with scar compared with normal patients with ischemic viable zones (ischemic viable 93 ± 27% [mean ± SD]; scar 37 ± 16%, p ≤ 0.01). Using N-13 ammonia kinetic modeling, flow and VD were reduced in the hypoperfused regions of patients with scar (ischemic viable flow: 0.65 ± 0.20 ml/min per g; scar: 0.36 ± 0.16 ml/min per g, p ≤ 0.01; VD: 3.9 ± 1.3 and 2.0 ± 1.07 ml/g, respectively, p ≤ 0.01). For detection of viable myocardium in these patients, the sensitivity and specificity were 100% and 80% for N-13 ammonia PET flow >0.45 ml/min per g; 100% and 70% for VD >2.0 ml/g; and 100% and 90% for both flow > 0.45 ml/min per g and VD > 2.0 ml/g, respectively. The positive and negative predictive values for the latter approach were 86% and 100%, respectively.Conclusions. In this cohort, patients having regions with flow ≤0.45 ml/min per g or VD ≤ 2.0 ml/g had scar. Viable myocardium had both flow >0.45 ml/min per g and VD > 2.0 ml/g. Nitrogen-13 ammonia kinetic modeling permits determination of blood flow and metabolic integrity in patients with previous myocardial infarction and can help differentiate between scar and ischemic but viable myocardium.(J Am Coll Cardiol 1997;29:537–43

Estimating the development of landrace and improved maize cultivars as a function of air temperature.

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Questions That Get Answered: The Construction of Instructional Conversations on Online Asynchronous Discussion Boards

Abstract On online asynchronous discussion boards, instructor questions are considered a driving force in student engagement and learning. Yet, students can and do choose not to answer questions from instructors. In this paper, the authors report on a qualitative study in which they analyzed instructor-student interaction on an asynchronous discussion board in order to determine which instructor's questions students were more likely to answer and why. They found that students were more likely to answer those instructor questions that were authentic and exhibited uptake of students' comments. Moreover, the students' orientation to those features suggests that students actively choose to engage in -and construct -coherent instructional interactions that characterize conversation rather than recitation

Sirolimus and kidney growth in autosomal dominant polycystic kidney disease

BACKGROUND: In autosomal dominant polycystic kidney disease (ADPKD), aberrant activation of the mammalian target of rapamycin (mTOR) pathway is associated with progressive kidney enlargement. The drug sirolimus suppresses mTOR signaling. METHODS: In this 18-month, open-label, randomized, controlled trial, we sought to determine whether sirolimus halts the growth in kidney volume among patients with ADPKD. We randomly assigned 100 patients between the ages of 18 and 40 years to receive either sirolimus (target dose, 2 mg daily) or standard care. All patients had an estimated creatinine clearance of at least 70 ml per minute. Serial magnetic resonance imaging was performed to measure the volume of polycystic kidneys. The primary outcome was total kidney volume at 18 months on blinded assessment. Secondary outcomes were the glomerular filtration rate and urinary albumin excretion rate at 18 months. RESULTS: At randomization, the median total kidney volume was 907 cm(3) (interquartile range, 577 to 1330) in the sirolimus group and 1003 cm(3) (interquartile range, 574 to 1422) in the control group. The median increase over the 18-month period was 99 cm(3) (interquartile range, 43 to 173) in the sirolimus group and 97 cm(3) (interquartile range, 37 to 181) in the control group. At 18 months, the median total kidney volume in the sirolimus group was 102% of that in the control group (95% confidence interval, 99 to 105; P=0.26). The glomerular filtration rate did not differ significantly between the two groups; however, the urinary albumin excretion rate was higher in the sirolimus group. CONCLUSIONS: In adults with ADPKD and early chronic kidney disease, 18 months of treatment with sirolimus did not halt polycystic kidney growth. (ClinicalTrials.gov number, NCT00346918.

In Vivo Imaging of Vesicular Monoamine Transporters in Human Brain Using [ 11 C]Tetrabenazine and Positron Emission Tomography

The pharmacokinetics of [ 11 CJtetrabenazine, a high-affinity radioligand for the monoamine vesicular transporter, were determined in living human brain using in vivo imaging by positron emission tomography (PET). The radiotracer showed high brain uptake and rapid washout from all brain regions with relatively slower clearance from regions of highest concentrations of monoamine vesicular transporters (striatum), resulting in clear differential visualization of these structures at short intervals after injection (10–20 min). As the first human PET imaging study of a vesicular neurotransmitter transporter, these experiments demonstrate that external imaging of vesicular transporters forms a new and valuable approach to the in vivo quantification of monoaminergic neurons, with potential application to the in vivo study of neurodegenerative disorders such as Parkinson's disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65743/1/j.1471-4159.1993.tb03521.x.pd

Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1±16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1±6 HU comparing right and left coronary artery and 56±9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291±65 HU in the ascending aorta, 334±93 HU in the pulmonary trunk, and 285±66 HU and 268±67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain