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Biomedical subjects

E A Swanson

Publications and source records attributed to E A Swanson.

At least 19 recordsLinked to original sources
PubMed2001

Transgene overexpression of alphaB crystallin confers simultaneous protection against cardiomyocyte apoptosis and necrosis during myocardial ischemia and reperfusion.

We investigated whether enhanced expression of alphaB crystallin, a stress-inducible molecular chaperone of the small heat shock family, can protect myocardial contractile apparatus against ischemia reperfusion (I/R) injury. Transgenic mice overexpressing alphaB crystallin were generated using the 0.76 kb rat alphaB crystallin cDNA cloned into a pCAGGS plasmid driven by a human cytomegalovirus expression system. Southern analysis confirmed transgene integration and Northern and Western blotting characterized expression (3.1-fold and 6.9-fold elevations in myocardial mRNA and protein levels, respectively). Extent of functional recovery over a 3 h reperfusion period following a 20 min ischemic period in transgenic and wild-type mouse hearts was assessed using an ex vivo work-performing heart preparation. The transgenic group displayed significantly higher values of DP at R45 min (29.14+/-1.9 mm Hg vs. 17.6+/-0.7 mm Hg), R60 min (31.56+/-1.7 mm Hg vs. 17.8+/-0.8 mm Hg), and R75 min (32.5+/-2.2 mm Hg vs. 16.9+/-0.9 mm Hg), and of dLVP/dt at R45 min (1740.2+/-111.5 mm Hg.s-1 vs. 548.7+/-82.2 mm Hg.s-1) and R60 min (1199.8+/-104.6 mm Hg.s-1 vs. 466.9+/-61.1 mm Hg.s-1). The transgenic group also displayed development of less oxidative stress, decreased extent of infarction, and attenuated cardiomyocyte apoptotic cell death. Transgene overexpression of alphaB crystallin was therefore successful in diminishing the independent contributory effects of both necrosis and apoptosis on I/R-induced cell death.

Actins↗
PubMed2000

Outcome indicators for direct and indirect caregiving.

Informal caregiving and outcomes for caregiving are an important part of health care and of particular importance in nursing. The purpose of this research is to report the results of a survey mailed to nursing experts for validation of the outcome labels Caregiver Role Performance: Direct Care and Caregiver Role Performance: Indirect Care and their accompanying indicators. Experts were asked to rate how important the identified indicators were for assessing those two outcomes. In addition, the respondents were asked to what extent nursing interventions influence the achievement of each identified indicator for Caregiver Role Performance: Direct Care and Caregiver Role Performance: Indirect Care. In general, the validity of the concept analysis work by the caregiver focus group was supported. Ten indicators for Caregiver Performance: Direct Care were retained, 1 was dropped that was considered most appropriate for indirect care, and 3 new indicators were added to reflect the nurse experts surveyed. For Caregiver Performance: Indirect Care, all of the indicators were retained.

Caregivers↗
PubMed1999

Overexpression of sarcoplasmic reticulum Ca(2+)-ATPase improves cardiac contractile function in hypothyroid mice.

OBJECTIVE: Prolonged cardiac contraction and relaxation in hypothyroidism are in part related to diminished expression of the gene coding for the calcium pump of the sarcoplasmic reticulum (SERCA2a). Therefore, we examined whether or not transgenic SERCA2a gene expression in mice may compensate for the cardiac effects of hypothyroidism. METHODS: SERCA2a mRNA and protein were analyzed from hearts of euthyroid and hypothyroid mice of wild-type or SERCA2a transgene status. Contractile function was studied in isolated left ventricular papillary muscles. RESULTS: We found significant decreases of SERCA2a mRNA and protein levels in hearts of hypothyroid wild-type mice in comparison with euthyroid wild-type mice (controls). Papillary muscles from hypothyroid wild-type mice showed significant increases in time to peak contraction and relaxation times compared with controls. In contrast, SERCA2a mRNA and protein levels were significantly higher in hypothyroid SERCA2a transgenic mice than in hypothyroid wild-type mice. The transgene led to a functional improvement by compensating for the prolonged contraction and relaxation of papillary muscles. CONCLUSIONS: Our murine model of hypothyroidism revealed decreases in SERCA2a gene expression accompanied by prolonged contraction and relaxation of papillary muscles, and an improvement of the contractile phenotype due to compensated SERCA2a gene expression in SERCA2a transgenic mice.

Animals↗
PubMed1999

Altered cardiac phenotype in transgenic mice carrying the delta337 threonine thyroid hormone receptor beta mutant derived from the S family.

The heart has been recognized as a major target of thyroid hormone action. Our study investigates both the regulation of cardiac-specific genes and contractile behavior of the heart in the presence of a mutant thyroid hormone receptor beta1 (T3Rbeta1-delta337T) derived from the S kindred. The mutant receptor was originally identified in a patient with generalized resistance to thyroid hormone. Cardiac expression of the mutant receptor was achieved by a transgenic approach in mice. As the genes for myosin heavy chains (MHC alpha and MHC beta) and the cardiac sarcoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA2) are known to be regulated by T3, their cardiac expression was analyzed. The messenger RNA levels for MHC alpha and SERCA2 were markedly down-regulated, MHC beta messenger RNA was up-regulated. Although T3 levels were normal in these animals, this pattern of cardiac gene expression mimics a hypothyroid phenotype. Cardiac muscle contraction was significantly prolonged in papillary muscles from transgenic mice. The electrocardiogram of transgenic mice showed a substantial prolongation of the QRS interval. Changes in cardiac gene expression, cardiac muscle contractility, and electrocardiogram are compatible with a hypothyroid cardiac phenotype despite normal T3 levels, indicating a dominant negative effect of the T3Rbeta mutant.

Animals↗
PubMed1999

Who owns the rights to a teaching tool?

Copyright issues are not always clear, especially when multiple authors and roles are involved. The following question and response analyzes one such situation involving the rights to a teaching tool developed by a faculty member.

Copyright↗
PubMed1999

Genderly speaking.

Nurse authors and editors struggle to make writing smooth, while avoiding sexist language. This experienced author suggests several strategies for writing or editing in a gender-friendly way.

Female↗
PubMed1998

Topography of diabetic macular edema with optical coherence tomography.

OBJECTIVE: This study aimed to develop a protocol to screen and monitor patients with diabetic macular thickening using optical coherence tomography (OCT), a technique for high-resolution cross-sectional imaging of the retina. DESIGN: A cross-sectional pilot study was conducted. PARTICIPANTS: A total of 182 eyes of 107 patients with diabetic retinopathy, 55 eyes from 31 patients with diabetes but no ophthalmoscopic evidence of retinopathy, and 73 eyes from 41 healthy volunteers were studied. INTERVENTION: Six optical coherence tomograms were obtained in a radial spoke pattern centered on the fovea. Retinal thickness was computed automatically from each tomogram at a total of 600 locations throughout the macula. Macular thickness was displayed geographically as a false-color topographic map and was reported numerically as averages in each of nine regions. MAIN OUTCOME MEASURES: Correlation of OCT with slit-lamp biomicroscopy, fluorescein angiography, and visual acuity was measured. RESULTS: Optical coherence tomography was able to quantify the development and resolution of both foveal and extrafoveal macular thickening. The mean +/- standard deviation foveal thickness was 174 +/- 18 microns in normal eyes, 179 +/- 17 microns in diabetic eyes without retinopathy, and 256 +/- 114 microns in eyes with nonproliferative diabetic retinopathy. Foveal thickness was highly correlated among left and right eyes of normal eyes (mean +/- standard deviation difference of 6 +/- 9 microns). Foveal thickness measured by OCT correlated with visual acuity (r2 = 0.79). A single diabetic eye with no slit-lamp evidence of retinopathy showed abnormal foveal thickening on OCT. CONCLUSIONS: Optical coherence tomography was a useful technique for quantifying macular thickness in patients with diabetic macular edema. The topographic mapping protocol provided geographic information on macular thickness that was intuitive and objective.

Adult↗
PubMed1997

Optical biopsy with optical coherence tomography: feasibility for surgical diagnostics.

BACKGROUND: Optical coherence tomography (OCT) is a recently developed compact technology which uses infrared light to perform cross-sectional imaging on a micrometer scale. Since OCT provides imaging at a resolution comparable to conventional histology and does not require direct contact with the tissue surface, a role in real-time surgical diagnostics represents a logical extension. In this work, we test the feasibility of OCT for surgical diagnostics by demonstrating imaging in tissue relevent to microsurgical intervention, a previously undescribed observation. MATERIALS AND METHODS: Over 50 sites on nervous, reproductive, and microvascular specimens from 10 patients were examined postmortem with OCT. After imaging, tissue was registered with microinjections of dye, under visible light laser guidance, followed by routine histologic processing to confirm the identity of microstructure. RESULTS: The 16 +/- 1 microm resolution allowed subsurface microstructure to be identified at unprecedented resolution. Structures identified included fascicles of peripheral nerves, the internal elastic membrane of microvessels, and the granular layer of the cerebellum. CONCLUSIONS: The ability of OCT to provide micrometer-scale definition of tissue microstructure suggests a role in surgical diagnostics. Future in vivo investigations are merited to establish its utility for morbidity reduction associated with surgical intervention.

Animals↗
PubMed1997

Argon laser retinal lesions evaluated in vivo by optical coherence tomography.

PURPOSE: To assess the in vivo evolution of argon laser retinal lesions by correlating the cross-sectional structure from sequential optical coherence tomography with histopathologic sectioning. METHODS: Argon laser lesions were created in the retinas of Macaca mulatta and evaluated by cross-section optical coherence tomography, which was compared at selected time points with corresponding histopathology. RESULTS: Argon laser lesions induced an optical coherence tomography pattern of early outer retinal relative high reflectivity with subsequent surrounding relative low reflectivity that correlated well with histopathologic findings. The in vivo optical coherence tomography images of macular laser lesions clearly demonstrated differences in pathologic response by retinal layer over time. CONCLUSION: The novel sequential imaging of rapidly evolving macular lesions with optical coherence tomography provides new insight into the patterns of acute tissue response by cross-sectional layer. This sequential imaging technique will aid in our understanding of the rapid evolution of retinal pathology and response to treatment in the research and clinical setting.

Animals↗
PubMed1997

Assessing atherosclerotic plaque morphology: comparison of optical coherence tomography and high frequency intravascular ultrasound.

BACKGROUND: OCT can image plaque microstructure at a level of resolution not previously demonstrated with other imaging techniques because it uses infrared light rather than acoustic waves. OBJECTIVES: To compare optical coherence tomography (OCT) and intravascular ultrasound (IVUS) imaging of in vitro atherosclerotic plaques. METHODS: Segments of abdominal aorta were obtained immediately before postmortem examination. Images of 20 sites from five patients were acquired with OCT (operating at an optical wavelength of 1300 nm which was delivered to the sample through an optical fibre) and a 30 MHz ultrasonic transducer. After imaging, the microstructure of the tissue was assessed by routine histological processing. RESULTS: OCT yielded superior structural information in all plaques examined. The mean (SEM) axial resolution of OCT and IVUS imaging was 16 (1) and 110 (7), respectively, as determined by the point spread function from a mirror. Furthermore, the dynamic range of OCT was 109 dB compared with 43 dB for IVUS imaging. CONCLUSIONS: OCT represents a promising new technology for intracoronary imaging because of its high resolution, broad dynamic range, and ability to be delivered through intravascular catheters.

Aorta, Abdominal↗
PubMed1997

Caregiving: concept analysis and outcomes.

More than ever before, caregiving has become a salient public policy issue. A number of recent and anticipated demographic, economic and social changes have occurred that make it imperative for researchers to critically examine the impact of caregiving on family caregivers' health, behavior, emotions, and social status. Researchers at the University of Iowa College of Nursing are working to classify standardized nursing-sensitive patient outcomes for use in language development, practice, research, and education to evaluate the effectiveness of nursing interventions and clinical nursing services. This article focuses on family caregiving and the analysis of caregiver role performance in both direct and indirect care, linking outcomes and indicators, to enable nurses to promote the health of caregivers.

Caregivers↗
PubMed1996

Optical coherence tomography for optical biopsy. Properties and demonstration of vascular pathology.

BACKGROUND: Optical coherence tomography (OCT) is an recently developed medical diagnostic technology that uses back-reflected infrared light to perform in situ micron scale tomographic imaging. In this work, we investigate the ability of OCT to perform micron scale tomographic imaging of the internal microstructure of in vitro atherosclerotic plaques. METHODS AND RESULTS: Aorta and relevant nonvascular tissue were obtained at autopsy. Two-dimensional cross-sectional imaging of the exposed surface of the arterial segments was performed in vitro with OCT. A 1300-nm wavelength, superluminescent diode light source was used that allows an axial spatial resolution of 20 microns. The signal-to-noise ratio was 109 dB. Images were displayed in gray scale or false color, Imaging was performed over 1.5 mm into heavily calcified tissue, and a high contrast was noted between lipid- and water-based constituents, making OCT attractive for intracoronary imaging. The 20-microns axial resolution of OCT allowed small structural details such as the width of intimal caps and the presence of fissures to be determined. The extent of lipid collections, which had a low backscattering intensity, also were well documented. CONCLUSIONS: OCT represents a promising new technology for imaging vascular microstructure with a level of resolution not previously achieved with the use of other imaging modalities. It does not required direct contact with the vessel wall and can be performed with a catheter integrated with a relatively inexpensive optical fiber. The high contrast among tissue constituents, high resolution, and ability to penetrate heavily calcified tissue make OCT an attractive new imaging technology for intracoronary diagnostics.

Arteriosclerosis↗
PubMed1996

Characterization of epiretinal membranes using optical coherence tomography.

OBJECTIVE: To evaluate optical coherence tomography (OCT), a novel noncontact and noninvasive imaging technique, for the diagnosis and quantitative characterization of epiretinal membranes. METHODS: Optical coherence tomography is similar to an ultrasound B-scan, except that light rather than sound is used, which enables higher resolution. Over a 2-year period, OCT was used to examine 186 eyes of 160 patients who had a diagnosis of an epiretinal membrane. Optical coherence tomograms were correlated with visual acuity, slit-lamp biomicroscopy, fluorescein angiography, and funds photography. RESULTS: Based on OCT, the epiretinal membrane was clearly separated from the retina with focal points of attachment in 49 eyes and globally adherent (no observed separation) in 125 eyes. Globally adherent membranes were associated with the following features: macular pseudohole (32 eyes), a difference in optical reflectivity between the membrane and retina (65 eyes), and/or a visible membrane tuft or edge (92 eyes). The membrane was undetectable on OCT in 12 eyes. The membrane thickness (mean +/- standard deviation) was 61 +/- 28 microns in the 169 eyes in which the thickness could be measured with OCT. Mean central macular thickness measured with OCT correlated with visual acuity (R2 = 0.73). CONCLUSION: Optical coherence tomography was able to provide a structural assessment of the macula that was useful in the preoperative and postoperative evaluation of epiretinal membrane surgery. Quantitative measurements and the assessment of membrane adherence with OCT may be useful in characterizing the surgical prognosis of eyes with an epiretinal membrane.

Aged↗
PubMed1996

Reproducibility of nerve fiber layer thickness measurements using optical coherence tomography.

PURPOSE: Optical coherence tomography (OCT) is a new technology that uses near-infrared light in an interferometer to produce approximately 10-microns resolution cross-sectional images of the tissue of interest. The authors performed repeated quantitative assessment of nerve fiber layer thickness in individuals with normal and glaucomatous eyes, and they evaluated the reproducibility of these measurements. METHODS: The authors studied 21 eyes of 21 subjects by OCT. Each subject underwent five repetitions of a series of scans on five separate occasions within a 1-month period. Each series consisted of three circular scans around the optic nerve head (diameters, 2.9, 3.4, and 4.5 mm). Each series was performed separately using internal (fixation with same eye being studied) and external (fixation with contralateral eye) fixation techniques. The eye studied and the sequence of testing were assigned randomly. RESULTS: Internal fixation (IF), in general, provides a slightly higher degree of reproducibility than external fixation (EF). Reproducibility was better in a given eye on a given visit than from visit to visit. Reproducibility as measured by intraclass correlation coefficients were as follows: circle diameter (CD), 2.9 mm, 0.51/0.57 (normal/glaucoma) (IF), 0.43/0.54 (EF); CD, 3.4 mm, 0.56/0.52 (IF), 0.43/0.61 (EF); CD, 4.5 mm, 0.53/0.43 (IF), 0.42/0.49 (EF). CONCLUSIONS: Nerve fiber layer thickness can be reproducibly measured using OCT. Internal is superior to external fixation; each circle diameter tested provides adequate reproducibility.

Aged↗
PubMed1996

Optical coherence tomography of age-related macular degeneration and choroidal neovascularization.

OBJECTIVE: The authors used optical coherence tomography (OCT), a new technique for cross-sectional imaging of the retina, to morphologically study eyes with nonexudative and exudative age-related macular degeneration (AMD). In patients with untreated exudative AMD, OCT was compared with fluorescein angiography in the identification and classification of choroidal neovascularization (CNV). METHODS: Optical coherence tomography imaging is analogous to ultrasound, except that the use of light rather than sound enables higher longitudinal resolution with a noncontact and noninvasive measurement. Optical coherence tomography was performed on 391 patients with the clinical diagnosis of AMD and was compared with conventional clinical examination to establish the cross-sectional morphology of different lesions and to develop a classification scheme for CNV. Optical coherence tomograms and fluorescein angiograms then were reviewed and correlated independently in 90 eyes of 86 patients who had exudative AMD without previous laser treatment. RESULTS: Pigmentary changes, soft drusen, and detachments of the neurosensory retina and retinal pigment epithelium all had distinct presentations on OCT. Subretinal and intraretinal fluid caused changes in retinal thickness or elevation that could be quantified directly from the images. Choroidal neovascularization was evident in the tomograms as a thickening and fragmentation of a reflective layer, which corresponded to the retinal pigment epithelium and choriocapillaris. Changes in the reflection from this layer were observed during the progression of neovascularization, and after laser photocoagulation treatment. Classic CNV consistently presented with well-defined boundaries on OCT, whereas occult CNV had a variable cross-sectional appearance. CONCLUSIONS: Optical coherence tomography was useful in quantitatively evaluating subretinal and intraretinal fluid, assessing possible subfoveal involvement of neovascularization, and in monitoring CNV before and after laser photocoagulation. Optical coherence tomography was unable to detect CNV beneath serous pigment epithelial detachments. Optical coherence tomography may have potential in accurately defining the boundaries in a subset of angiographically occult CNV.

Adult↗