583 research outputs found

    Copyright Ownership Of Scholarly Works Created By University Faculty And Posted On School-Provided Web Pages

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    This article will discuss the issue of copyright ownership to a scholarly work that is written by a university faculty member. The analysis will include a general discussion of copyright law, including the work for hire doctrine, the development and applicability of the common law exception to the work for hire doctrine for academic writings, whether a university professor publishing a scholarly article is within the scope of employment, web page publishing issues for professors who want to put their papers online and a discussion of the most practical strategies for professors who want to claim copyright ownership to their scholarly works

    Myocardial mechanics in young adult patients with diabetes mellitus: Effects altered load, inotropic state and dynamic exercise

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    AbstractThe disease entity “diabetic cardiomyopathy” has been extensively described in young patients with diabetes in the absence of ischemic, hypertensive or valvular heart disease. The most convincing data have been a 30% to 40% incidence of decreased radionuclide angiographic left ventricular ejection fraction response to dynamic exercise. In the current study, the hypothesis was tested that this abnormal ejection fraction response was due to alterations in ventricular loading conditions or cardiac autonomic innervation (extrinsic factors), or both, rather than to abnormalities in intrinsic ventricular systolic fiber function (contractility).Twenty normotensive patients with diabetes (mean age 30 ± 5 years, mean duration 15 ± 6 years) and 20 age-matched normal subjects were studied. All patients with diabetes had a normal treadmill exercise tolerance test without evidence of myocardial ischemia. By radionuclide angiography, all normal subjects increased ejection fraction with exercise (62 ± 4% to 69 ± 6%; p < 0.001). In contrast, 11(55%) of 20 patients with diabetes maintained or increased ejection fraction with exercise (group 1; 62 ± 4% to 69 ± 6%; p < 0.001) and 9 (45%) of 20 showed an exercise-induced decrease (group 2; 73 ± 4% to 66 ± 6%; p < 0.001). No difference in the incidence of microangiopathy, as noted by funduscopic examination, was present between the diabetic groups. Despite the abnormal ejection fraction response to exercise in the group 2 patients with diabetes, all patients with diabetes had a nor response to afterload manipulation, normal baseline ventricular contractility as assessed by load- and heart rate-independent end-systolic indexes and normal contractile reserve as assessed with dobutamine challenge.Autonomic dysfunction did not explain the disparate results between the group 2 patients' radionuclide angiographic data and their load-independent tests of ventricular contractility and reserve. In addition, the high ejection fraction at rest in group 2 patients (73±4% versus 62 ± 4% for normal subjects; p < 0.001) was not related to the abnormal tests of autonomic function. Thus, when left ventricular systolic performance was assessed by load- and rate-independent indexes, there was no evidence for cardiomyopathy in young adult patients with diabetes who have normal blood nressure and no ischemie heart disease

    Left Ventricular Function by Pressure‐Volume Loop Analysis before and after Percutaneous Repair of Large Atrial Septal Defects

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    Aim The intent of the present study was to evaluate changes in ventricular function with percutaneous closure of atrial septal defect (ASD), as it is associated with alterations in ventricular loading and function. Transcatheter occlusion of ASD imparts acute changes in volume loading of the left ventricle (LV) that obscures measurement of ventricular function by load‐dependent indices. To differentiate between changes in ventricular loading and function, load‐independent indices of ventricular function must be utilized . Methods During transcatheter occlusion of ASD, subjects underwent measurement of LV pressure and volume by the conductance catheter method. Load‐dependent indices of ventricular function included: systolic and diastolic pressures, +dP/dt max , and −dP/dt max . Load‐independent indices included: elastance and tau, the preload‐independent time constant ofisovolumic relaxation. To obtain elastance, afterload was augmented by phenylephrine bolus pre‐ and post‐device occlusion . Results In total, 29 patients (age 2–79 years) underwent ASD device occlusion (device size 12–38 mm, median 28 mm). Load‐dependent indices were obtained in all, and satisfactory pressure‐volume loops in 11. At baseline, LV end‐diastolic pressure was 5–23 mmHg (13 ± 5 mmHg) and tau was 31 ± 6 ms. Postclosure of the ASD, LV systolic and diastolic pressures rose by 10 ± 11 mmHg and 5 ± 3 mmHg, respectively (P < 0.05), and +dP/dt max rose from 1,288 ± 313 mmHg/sec to 1,415 ± 465 mmHg/sec (P < 0.05), but −dP/dt max was unchanged. Elastance significantly improved (9.4 ± 8.3 mmHg/mL vs. 13.0 ± 7.3 mmHg/mL, P < 0.05) and tau was unchanged . Conclusions Transcatheter occlusion of ASD is associated with acute improvement in load‐independent indices of systolic function in this cohort, without significant worsening of the preload‐independent index of diastolic function . (J Interven Cardiol 2014;27:204–211)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106889/1/joic334.pd

    Effect of abrupt mitral regurgitation after balloon valvuloplasty on myocardial load and performance

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    AbstractThe concept that mitral regurgitation masks myocardial dysfunction by reducing afterload and augmenting ejection performance has not been well established in humans. The effect of abruptly produced mitral regurgitation on left ventricular loading and performance was therefore evaluated in five patients who developed this complication after an otherwise successful percutaneous balloon mitral valvuloplasty. Mitral valve area by Gorlin formula calculated with forward flow increased from 0.92 ± 0.14 to 2.75 ± 0.82 cm2. Mean left atrial pressure did not decrease (19 ± 4 to 19 ± 6 mm Hg). The size of the left atrial Vwave relative to mean left atrial pressure (peak V— mean left atrial pressure) increased from 7 ± 4 to 19 ± 6 mm Hg. Angiographic mitral regurgitation increased from 0+ or 1 + to >3+ in each patient and regurgitant fraction increased from 0.23 ± 0.11 to 0.55 ± 0.99 (p < 0.01).End-diastolic volume increased modestly from 148 ± 15 to 159 ± 15 ml (p = NS). Heart rate increased from 54 ± 5 to 71 ± 8 heats/min (p < 0.05), which may have prevented further increases in preload by shortening the filling period. End-systolic stress decreased by 32% from 277 ± 34 to 188 ± 52 kdyn/cm2(p < 0.01) as a result of a 25% decrease in end-systolic pressure from 121 ± 8 to 91 ± 7 mm Hg and a 16% decrease in end-systolic volume from 67 ± 13 to 56 ± 8 ml (p = NS). Contractility estimated from the preload-corrected ejection fraction-afterload relation decreased in one of the five patients and did not increase in the others despite an increase in heart rate, possibly as a result of myocardial depression from the balloon procedure itself. Nevertheless, the decrease in end-systolic volume could not be attributed to a net increase in contractility. The result of the changes in loading was an increase in ejection fraction from 0.55 ± 0.05 to 0.65 ± 0.04 (p < 0.05).Thus, abruptly produced mitral regurgitation increases ejection performance by reducing afterload without increasing contractility. This should be taken into consideration when anticipating the results of valve replacement for acute or subacute mitral regurgitation

    Application of end-systolic pressure-volume and pressure-wall thickness relations in conscious dogs

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    The usefulness of end-systolic measures of ventricular function was compared with that of standard contractility indexes in conscious dogs. End-systolic relations between left ventricular pressure and volume and between pressure and wall thickness were analyzed in dogs previously instrumented with ultrasonic crystals. Progressive angiotensin infusions were used to generate computer-averaged pressure-volume and pressure-wall thickness loops. Both relations were linear in every study and highly reproducible.With low and high dose dobutamine, the end-systolic pressure-volume relations were significantly displaced, with increased slope and inconsistent changes in intercept. This relation was more useful than the ejection fraction for detecting contractility increases at different afterloads, but it showed no advantage over maximal left ventricular dP/dt at all ranges of preload and after-load. The end-systolic pressure-volume relations were insensitive for detecting mild decreases in inotropic state produced by propranolol, and maximal dP/dt was superior for detecting such mild acutely reduced contractility. The end-systolic pressure-wall thickness relations showed displacement with dobutamine, although slope and intercept changes were not significant; these relations did not detect mild decreases in contractility produced by propranolol.It is concluded that the end-systolic pressure-volume relation and a simplified end-systolic measure using pressure and wall thickness provide sensitive, load-independent and reproducible approaches for defining acute increases in left ventricular contractility in conscious animals. Maximal dP/dt was equally effective for defining these increases in contractility and more sensitive for detecting slight acute decreases in contractility

    B-type natriuretic peptide as a marker for cardiac dysfunction in anthracycline-treated children

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    Background Anthracyclines (AC) are useful antineoplastic agents, whose utility is limited by progressive cardiotoxicity. Our purpose was to evaluate plasma B-type natriuretic peptide (BNP), as a screening test for detecting late cardiac dysfunction in AC-treated children and to determine the prevalence of late cardiac dysfunction at low cumulative AC doses. Materials and Methods This was a prospective study in which patients who had completed AC therapy at least 1 year earlier, underwent a detailed echocardiogram and a simultaneous BNP level. Cardiac dysfunction was defined as any one of the following: shortening fraction (FS) 60 g·cm −2 , abnormal VCFc: ESWS ratio or decreased mitral inflow velocity (E/A) ratios, compared to age-specific norms. Results The cohort (n = 63) included 37 males with a median age of 13.1 years (range, 6.5–26.5 years). Cardiac dysfunction was found in 26 (41%) patients and in 40% of patients who received cumulative doses <150 mg·m −2 . ESWS was the most common abnormality. Mean BNP levels in the subset with abnormal function were significantly higher than the normal group (23.4 ± 25.3 vs. 14.2 ± 8.9 pg·ml −1 , P  = 0.02). Conclusions Plasma BNP was significantly elevated in AC-treated patients with late cardiac dysfunction, although there was considerable overlap of levels between groups with and without cardiac dysfunction. BNP may need further evaluation as a serial index of cardiac function in this population. Cardiac dysfunction was observed in a significant proportion of patients, even at low cumulative AC doses. Pediatr Blood Cancer 2007;49:812–816. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57395/1/21100_ftp.pd
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