Iowa City Veterans Administration Medical Center

Iowa City, IA, United States

Iowa City Veterans Administration Medical Center

Iowa City, IA, United States
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Alleman B.W.,University of Iowa | Luger T.,University of Iowa | Reisinger H.S.,Iowa City Veterans Administration Medical Center | Martin R.,University of Iowa | And 3 more authors.
Journal of General Internal Medicine | Year: 2011

BACKGROUND: There are growing reports of United States (US) residents traveling overseas for medical care, but empirical data about medical tourism are limited. OBJECTIVE: To characterize the businesses and business practices of entities promoting medical tourism and the types and costs of procedures being offered. DESIGN, PARTICIPANTS, AND OUTCOMES: Between June and August 2008, we conducted a telephone survey of all businesses engaged in facilitating overseas medical travel for US residents. We collected information from each company including: the number of employees; number of patients referred overseas; medical records security processes; destinations to which patients were referred; treatments offered; treatment costs; and whether patient outcomes were collected. RESULTS: We identified 63 medical tourism companies and 45 completed our survey (71%). Companies had a meanof9.8 employees and had referred an average of 285 patients overseas (a total of approximately 13,500 patients). 35 (79%) companies reported requiring accreditation of foreign providers, 22 (50%) collected patient outcome data, but only 17 (39%) described formal medical records security policies. The most common destinations were India (23 companies, 55%), Costa Rica (14, 33%), and Thailand (12, 29%). The most common types of care included orthopedics (32 companies, 73%), cardiac care (23, 52%), and cosmetic surgery (29, 66%). 20 companies (44%) offered treatments not approved for useinthe US-most commonly stem cell therapy. Average costs for common procedures, CABG ($18,600) and knee arthroplasty ($10,800), were similar to previous reports. CONCLUSIONS: The number of Americans traveling overseas for medical care with assistance from medical tourism companies is relatively small. Attention to medical records security and patient outcomes is variable and cost-savings are dependent on US prices. That said, overseas medical care can be a reasonable alternative for price sensitive patients in need of relatively common, elective medical procedures. © 2010 Society of General Internal Medicine.

Zhang L.,University of Iowa | Lee K.,University of Iowa | Niemeijer M.,University of Iowa | Niemeijer M.,IDx LLC | And 5 more authors.
Investigative Ophthalmology and Visual Science | Year: 2012

Purpose. We developed and evaluated a fully automated 3-dimensional (3D) method for segmentation of the choroidal vessels, and quantification of choroidal vasculature thickness and choriocapillaris-equivalent thickness of the macula, and evaluated repeat variability in normal subjects using standard clinically available spectral domain optical coherence tomography (SD-OCT). Methods. A total of 24 normal subjects was imaged twice, using clinically available, 3D SD-OCT. A novel, fully-automated 3D method was used to segment and visualize the choroidal vasculature in macular scans. Local choroidal vasculature and choriocapillaris-equivalent thicknesses were determined. Re-producibility on repeat imaging was analyzed using overlapping rates, Dice coefficient, and root mean square coefficient of variation (CV) of choroidal vasculature and choriocapillaris-equivalent thicknesses. Results. For the 6×6 mm2 macula-centered region as depicted by the SD-OCT, average choroidal vasculature thickness in normal subjects was 172.1 μm (95% confidence interval [CI] 163.7-180.5 μm) and average choriocapillaris-equivalent thickness was 23.1 μm (95% CI 20.0-26.2 μm). Overlapping rates were 0.79 ± 0.07 and 0.75 ± 0.06, Dice coefficient was 0.78 ± 0.08, CV of choroidal vasculature thickness was 8.0% (95% CI 6.3%-9.4%), and of choriocapillaris-equivalent thickness was 27.9% (95% CI 21.0%-33.3%). Conclusions. Fully automated 3D segmentation and quantitative analysis of the choroidal vasculature and choriocapillaris-equiva-lent thickness demonstrated excellent reproducibility in repeat scans (CV 8.0%) and good reproducibility of choriocapillaris-equivalent thickness (CV 27.9%). Our method has the potential to improve the diagnosis and management of patients with eye diseases in which the choroid is affected. © 2012 The Association for Research in Vision and Ophthalmology, Inc.

Elkins J.M.,University of Iowa | Daniel M.,Czech Technical University | Pedersen D.R.,University of Iowa | Singh B.,University of Iowa | And 4 more authors.
Clinical Orthopaedics and Related Research | Year: 2013

Background: Obesity has reached epidemic proportions in the United States. Recently, obesity, especially morbid obesity, has been linked to increased rates of dislocation after THA. The reasons are unclear. Soft tissue engagement caused by increased thigh girth has been proposed as a possible mechanism for decreased joint stability. Questions/Purposes: We asked (1) whether thigh soft tissue impingement could decrease THA stability, and if so, at what level of BMI this effect might become evident; and (2) how THA construct factors (eg, head size, neck offset, cup abduction) might affect stability in the morbidly obese. Methods: The obesity effect was explored by augmenting a physically validated finite element model of a total hip construct previously comprising just implant hardware and periarticular (capsular) soft tissue. The model augmentation involved using anatomic and anthropometric data to include graded levels of increased thigh girth. Parametric computations were run to assess joint stability for two head sizes (28 and 36 mm), for normal versus high neck offset, and for multiple cup abduction angles. Results: Thigh soft tissue impingement lowered the resistance to dislocation for BMIs of 40 or greater. Dislocation risk increased monotonically above this threshold as a function of cup abduction angle, independent of hardware impingement events. Increased head diameter did not substantially improve joint stability. High-offset necks decreased the dislocation risk. Conclusions: Excessive obesity creates conditions that compromise stability of THAs. Given such conditions, our model suggests reduced cup abduction, high neck offset, and full-cup coverage would reduce the risks of dislocation events. © 2012 The Association of Bone and Joint Surgeons®.

Elkins J.M.,University of Iowa | Pedersen D.R.,University of Iowa | Callaghan J.J.,University of Iowa | Callaghan J.J.,Iowa City Veterans Administration Medical Center | Brown T.D.,University of Iowa
Clinical Orthopaedics and Related Research | Year: 2013

Background: Hypothesized risk factors for fracture of ceramic liners include impingement, edge-loading, and cup malpositioning. These risk factors are similar to those for generation of stripe wear. However, it is unclear whether the biomechanical conditions contributing to stripe wear generation also increase the risk for ceramic liner fracture Questions/purposes: We asked whether (1) head stripe wear propensity; and (2) cup orientation would correlate with alumina liner fracture risk for instances of normal and elevated body weight. Methods: An eXtended Finite Element Method (XFEM) model was developed to investigate these mechanisms. Liner fracture risk for 36-mm alumina bearings was studied by simulating two fracture-prone motions: stooping and squatting. Twenty-five distinct cup orientations were considered with variants of both acetabular inclination and anteversion. Four separate body mass indices were considered: normal (25 kg/m2) and three levels of obesity (33, 42, and 50 kg/m2). Material properties were modified to simulate alumina with and without the presence of dispersed microflaws. The model was validated by corroboration with two previously published ceramic liner fracture studies. Results: Of 200 XFEM simulations with flaw-free alumina, fracture occurred in eight instances, all of them involving obesity. Each of these occurred with cups in ≤ 37 inclination and in 0 anteversion. For 200 corresponding simulations with microflawed alumina, fracture propensity was greatest for cups with higher (edge loading-associated) scraping wear. Fracture risk was greatest for cups with lower inclination (average 42 for fractured cases versus 48 for nonfractured cases) and lower anteversion (9 versus 20). Conclusions: Fracture propensity for 36-mm liners was elevated for cups with decreased anteversion and/or inclination and under conditions of patient obesity. Clinical Relevance: Factors causing stripe wear, including obesity and cup malpositioning, also involve increased risk of ceramic liner fracture and merit heightened concern. © 2012 The Association of Bone and Joint Surgeons®.

Elkins J.M.,University of Iowa | Callaghan J.J.,University of Iowa | Callaghan J.J.,Iowa City Veterans Administration Medical Center | Brown T.D.,University of Iowa
Clinical Orthopaedics and Related Research | Year: 2014

Background: Large-diameter femoral heads for metal-on-metal THA hold theoretical advantages of joint stability and low bearing surface wear. However, recent reports have indicated an unacceptably high rate of wear-associated failure with large-diameter bearings, possibly due in part to increased wear at the trunnion interface. Thus, the deleterious consequences of using large heads may outweigh their theoretical advantages. Questions/purposes: We investigated (1) to what extent femoral head size influenced stability in THA for several dislocation-prone motions; and the biomechanics of wear at the trunnion interface by considering the relationship between (2) wear potential and head size and (3) wear potential and other factors, including cup orientation, type of hip motion, and assembly/impaction load. Methods: Computational simulations were executed using a previously validated nonlinear contact finite element model. Stability was determined at 36 cup orientations for five distinct dislocation challenges. Wear at the trunnion interface was calculated for three separate cup orientations subjected to gait, stooping, and sit-to-stand motions. Seven head diameters were investigated: 32 to 56 mm, in 4-mm increments. Results: Stability improved with increased diameter, although diminishing benefit was seen for sizes of greater than 40 mm. By contrast, contact stress and computed wear at the trunnion interface all increased unabatedly with increasing head size. Increased impaction forces resulted in only small decreases in trunnion wear generation. Conclusions: These data suggest that the theoretical advantages of large-diameter femoral heads have a limit. Diameters of greater than 40 mm demonstrated only modest improvement in terms of joint stability yet incurred substantial increase in wear potential at the trunnion. Clinical Relevance: Our model has potential to help investigators and designers of hip implants to better understand the optimization of trunnion design for long-term durability. © 2013 The Association of Bone and Joint Surgeons®.

Adkisson H.D.,ISTO Technologies Inc. | Martin J.A.,University of Iowa | Amendola R.L.,University of Iowa | Milliman C.,ISTO Technologies Inc. | And 7 more authors.
American Journal of Sports Medicine | Year: 2010

Background: Donor-site morbidity, limited numbers of cells, loss of phenotype during ex vivo expansion, and age-related decline in chondrogenic activity present critical obstacles to the use of autologous chondrocyte implantation for cartilage repair. Chondrocytes from juvenile cadaveric donors may represent an alternative to autologous cells. Hypothesis/Purpose: The authors hypothesized that juvenile chondrocyte would show stronger and more stable chondrogenic activity than adult cells in vitro and that juvenile cells pose little risk of immunologic incompatibility in adult hosts. Study Design: Controlled laboratory study. Methods: Cartilage samples were from juvenile (<13 years old) and adult (>13 years old) donors. The chondrogenic activity of freshly isolated human articular chondrocytes and of expanded cells after monolayer culture was measured by proteoglycan assay, gene expression analysis, and histology. Lymphocyte proliferation assays were used to assess immunogenic activity. Results: Proteoglycan content in neocartilage produced by juvenile chondrocytes was 100-fold higher than in neocartilage produced by adult cells. Collagen type II and type IX mRNA in fresh juvenile chondrocytes were 100- and 700-fold higher, respectively, than in adult chondrocytes. The distributions of collagens II and IX were similar in native juvenile cartilage and in neocartilage made by juvenile cells. Juvenile cells grew significantly faster in monolayer cultures than adult cells (P =.002) and proteoglycan levels produced in agarose culture was significantly higher in juvenile cells than in adult cells after multiple passages (P <.001). Juvenile chondrocytes did not stimulate lymphocyte proliferation. Conclusion: These results document a dramatic age-related decline in human chondrocyte chondrogenic potential and show that allogeneic juvenile chondrocytes do not stimulate an immunologic response in vivo. Clinical Relevance: Juvenile human chondrocytes have greater potential to restore articular cartilage than adult cells, and may be transplanted without the fear of rejection, suggesting a new allogeneic approach to restoring articular cartilage in older individuals. © 2010 The Author(s).

Abu Rajab M.,University of Iowa | Guerin L.,University of Iowa | Lee P.,Scripps Research Institute | Brown K.E.,University of Iowa | Brown K.E.,Iowa City Veterans Administration Medical Center
Histopathology | Year: 2014

Aims: Hepatic iron deposition unrelated to hereditary haemochromatosis is common in cirrhosis. The aim of this study was to determine whether hepatic haemosiderosis secondary to cirrhosis is associated with iron deposition in extrahepatic organs. Methods and results: Records of consecutive adult patients with cirrhosis who underwent autopsy were reviewed. Storage iron was assessed by histochemical staining of sections of liver, heart, pancreas and spleen. HFE genotyping was performed on subjects with significant liver, cardiac and/or pancreatic iron. The 104 individuals were predominantly male (63%), with a mean age of 55 years. About half (46%) had stainable hepatocyte iron, 2+ or less in most cases. In six subjects, there was heavy iron deposition (4+) in hepatocytes and biliary epithelium. All six of these cases had pancreatic iron and five also had cardiac iron. None of these subjects had an explanatory HFE genotype. Conclusions: In this series, heavy hepatocyte iron deposition secondary to cirrhosis was commonly associated with pancreatic and cardiac iron. Although this phenomenon appears to be relatively uncommon, the resulting pattern of iron deposition is similar to haemochromatosis. Patients with marked hepatic haemosiderosis secondary to cirrhosis may be at risk of developing extrahepatic complications of iron overload. © 2014 John Wiley & Sons Ltd.

Elkins J.M.,University of Iowa | Kruger K.M.,University of Iowa | Pedersen D.R.,University of Iowa | Callaghan J.J.,University of Iowa | And 2 more authors.
Journal of Orthopaedic Research | Year: 2012

While favorable tribological properties and allowance for larger femoral head sizes have made metal-on-metal (MoM) bearings an increasingly popular choice for total hip arthroplasty, concerns have mounted regarding adverse reactions to metal wear debris and ions. MoM cups differ from conventional polyethylene cups in terms of edge profile design and reductions from full hemisphericity, suggesting differences in loading at or near the cup edge, especially during subluxation events. Finite element analysis was used to investigate the effects of cup orientation and lip edge curvature on damage propensity for edge or near-edge loading during subluxation. Increased cup lip radius (resulting in reduced articular arc) had a detrimental effect upon subluxation-free hip range of motion and upon dislocation resistance. Contact stresses near the cup edge demonstrated complex relationships between edge radius and cup orientation, with peak stresses being influenced by both variables. The tendency for scraping wear at the egress site demonstrated similarly complex dependencies. These data indicate that acetabular cup design is an important determinant of edge and near-edge loading damage propensity. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc.

Elkins J.M.,University of Iowa | O'Brien M.K.,University of Iowa | Stroud N.J.,University of Iowa | Pedersen D.R.,University of Iowa | And 3 more authors.
Clinical Orthopaedics and Related Research | Year: 2011

Background: Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes: We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods: Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results: Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions: Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. © 2010 The Association of Bone and Joint Surgeons®.

Abdalla M.Y.,Hashemite University | Mathahs M.M.,Iowa City Veterans Administration Medical Center | Ahmad I.M.,Hashemite University
European Journal of Internal Medicine | Year: 2012

Hepatic nonalcoholic fatty liver disease (NAFLD) is known to exacerbate liver injury due to chronic hepatitis C infection. Heme oxygenase-1 (HO-1) is an important protective antioxidative defense enzyme that is known to be induced in response to NAFLD and other liver injuries. The aim of this study was to evaluate HO-1 expression in HCV infected human livers with concomitant NAFLD. Methods: We compared levels of HO-1 in NAFLD liver biopsies from patients with or without chronic HCV infection using immunohistochemistry, immunoblots and real time RT-PCR. We also evaluated frozen sections of liver with dihydroethidium (DHE) or dichlorofluorescein (DCF) fluorescence staining to evaluate O2- and peroxide production respectively. Results: HO-1 expression was only increased in NAFLD livers without HCV infection, while HCV infected livers showed reduced HO-1 levels, regardless whether NAFLD was present. In uninfected livers with NAFLD, HO-1 expression was primarily localized in hepatocytes containing fat and areas of injury around the central vein. However, both NAFLD with and without concomitant HCV infection showed high levels of O2- or peroxide production compared to normal human liver control samples. Conclusions: These findings support the hypothesis that NAFLD is an important process for hepatocyte oxidative stress and injury in liver diseases. They also suggest that HCV can repress HO-1 induction in vivo even when other inducers of HO-1 are present. © 2012 European Federation of Internal Medicine.

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