A Protocol for Simultaneous In Vivo Imaging of Cardiac and Neuroinflammation in Dystrophin-Deficient MDX Mice Using [18F]FEPPA PET.

Duchenne muscular dystrophy (DMD) is a neuromuscular disorder caused by dystrophin loss-notably within muscles and the central neurons system. DMD presents as cognitive weakness, progressive skeletal and cardiac muscle degeneration until pre-mature death from cardiac or respiratory failure. Innovative therapies have improved life expectancy; however, this is accompanied by increased late-onset heart failure and emergent cognitive degeneration. Thus, better assessment of dystrophic heart and brain pathophysiology is needed. Chronic inflammation is strongly associated with skeletal and cardiac muscle degeneration; however, neuroinflammation's role is largely unknown in DMD despite being prevalent in other neurodegenerative diseases. Here, we present an inflammatory marker translocator protein (TSPO) positron emission tomography (PET) protocol for in vivo concomitant assessment of immune cell response in hearts and brains of a dystrophin-deficient mouse model [mdx:utrn(+/-)]. Preliminary analysis of whole-body PET imaging using the TSPO radiotracer, [18F]FEPPA in four mdx:utrn(+/-) and six wildtype mice are presented with ex vivo TSPO-immunofluorescence tissue staining. The mdx:utrn(+/-) mice showed significant elevations in heart and brain [18F]FEPPA activity, which correlated with increased ex vivo fluorescence intensity, highlighting the potential of TSPO-PET to simultaneously assess presence of cardiac and neuroinflammation in dystrophic heart and brain, as well as in several organs within a DMD model.

Formative Research: Using a Community-Based Participatory Research Approach to Develop an Oral Health Intervention for Migrant Mexican Families.

Oral health is a leading unmet health need among migrant families. This article describes the 1-year, community-based participatory research (CBPR) approach employed to plan and develop a Líder Communitario (lay community health worker)-led educational intervention for Mexican migrant adult caregivers and their families in three underserved, remote communities in North San Diego County, California. Four partner organizations collaborated, reviewed existing oral health curricula, and sought extensive input on educational topics and research design from key informants, migrant caregivers, and Líderes Communitarios. Based on community stakeholder input, partners developed a logic model and drafted educational intervention materials. Key informants ( n = 28), including several members from two community advisory boards, ranked program priorities and intervention subgroup population via online survey. Three focus groups were conducted with Líderes Communitarios ( n = 22) and three with migrant families ( n = 30) regarding the oral health program's design and content. Twelve Líderes Communitarios reviewed draft intervention materials during two focus groups to finalize the curriculum, and their recommended changes were incorporated. Formative research results indicated that community stakeholders preferred to focus on adult caregivers and their families. A 5-week educational intervention with hands on demonstrations and colorful visuals was developed, covering the following topics: bacteria and tooth decay, oral hygiene, nutrition, gum disease, and dental services. The CBPR process engaged multiple community stakeholders in all aspects of planning and developing the educational intervention.

Discovery of oxathiapiprolin, a new oomycete fungicide that targets an oxysterol binding protein.

Oxathiapiprolin is the first member of a new class of piperidinyl thiazole isoxazoline fungicides with exceptional activity against plant diseases caused by oomycete pathogens. It acts via inhibition of a novel fungal target-an oxysterol binding protein-resulting in excellent preventative, curative and residual efficacy against key diseases of grapes, potatoes and vegetables. Oxathiapiprolin is being developed globally as DuPont™ Zorvec™ disease control with first registration and sales anticipated in 2015. The discovery, synthesis, optimization and biological efficacy are presented.

Novel operative anoscope for Ferguson hemorrhoidectomy: a feasibility study and comparative cohort analysis.

BACKGROUND: Operative hemorrhoidectomy can result in pain and altered continence from excessive excision of anoderm or surrounding tissue. We assessed a novel low-profile slotted anoscope to determine if the device would promote safe dissection, lessen trauma, and reduce operative times for hemorrhoidectomy. METHODS: Patients requiring hemorrhoidectomy (June 2008 - January 2010) underwent a prospective phase-2 trial evaluating a new operating anoscope (CAD, Ethicon Endosurgery, Cincinnati, OH). Demographics and perioperative end points including bleeding, pain, fecal incontinence, stenosis, and symptom recurrence were analyzed at 4 weeks, 3 months, 6 months, and 1 year postoperatively. We compared these to patients undergoing hemorrhoidectomy (February 2010 - November 2012) with a traditional Hill-Ferguson anoscope (THF). RESULTS: 40 patients (CAD, 20 vs THF, 20) were included. Presenting symptoms were similar, whereas mean duration of symptoms was longer for CAD (41.2 ± 8.4 vs 27 ± 9.5 months; P < .05). Estimated blood loss was lower for CAD [8.3 mL (range = 2-40 mL) vs 11.3 mL THF (range = 5-35 mL; P = .87)]. Mean operative times were lower for the CAD than the THF group (15.6 ± 3.4 vs 26.1 ± 4.1 minutes; P < .05). Visual analog pain scores were non-significantly increased in the THF group at 4 weeks (P = .23). At 3 months, 6 months, and 1 year, there was no difference in continence. CONCLUSION: The CAD anoscope reduced operative times for modified Ferguson (closed) hemorrhoidectomy when compared with traditional retractors. There was no difference in incontinence or pain between groups.

Community health partnerships for chronic disease prevention among Latinos: the San Diego Prevention Research Center.

Over 20 years ago, university-community partnerships (i.e., Prevention Research Centers [PRCs]) across the United States were funded by the Centers for Disease Control and Prevention to conduct research and training in order to promote health and prevent disease in underserved populations. In 2004, the San Diego PRC (SDPRC) became the first PRC to focus on obesity prevention and control in a community of mostly Mexican Americans/Mexican immigrants. The SDPRC was also the first PRC to comprise a university-community partnership with a school of public health, a school of medicine, and a federally qualified health center. In conjunction with two additional funded community partners and involvement of a community advisory board, the SDPRC seeks to develop effective intervention strategies that ultimately lead to behavior change. Now in its second cycle of funding, the SDPRC has identified three primary principles that are important for these and similar efforts: (1) developing culturally appropriate interventions requires community engagement; (2) building the evidence in a systematic and rigorous way yields meaningful strategies for translation to practice; and (3) translating evidence-based interventions to practice involves capacity building for both researchers and community partners. This article describes these principles to help others involved in similar intervention efforts identify the best approach for promoting health in their own communities.

Characterization of the Ang/Tie2 Signaling Pathway in the Diaphragm Muscle of DMD Mice.

In Duchenne muscular dystrophy (DMD), angiogenesis appears to be attenuated. Local administration of angiopoietin 1 (Ang1) has been shown to reduce inflammation, ischemia, and fibrosis in DMD mice. Ang1 is a vital vascular stabilizing factor that activates the endothelial cell receptor Tie2, leading to downstream pro-survival PI3K/Akt pathway activation and eNOS phosphorylation. In this study, we aimed to characterize the Ang/Tie2 signaling pathway within the diaphragm muscle of mouse models of DMD. Utilizing ELISA, immunoblots, and RT-qPCR, we demonstrated that Ang1 was downregulated, while the antagonist angiopoietin 2 (Ang2) was upregulated, leading to a decreased Ang1/Ang2 ratio. This correlated with a reduction in the phosphorylated Tie2/total Tie2 ratio. Interestingly, no significant differences in Akt or eNOS phosphorylation were observed, although DMD murine models did have elevated total Akt protein concentrations. These observations suggest that Ang1/Tie2 signaling may be dysregulated in the diaphragm muscle of DMD and further investigations may lead to new therapeutic interventions for DMD.

Genetic deletion of c-Jun amino-terminal kinase 3 (JNK3) modestly increases disease severity in a mouse model of multiple sclerosis.

The c-Jun amino terminal kinases (JNKs) regulate transcription, and studies suggest they contribute to neuropathology in the EAE model of MS. To examine the role of the JNK3 isoform, we compared EAE in JNK3 null mice to wild type (WT) littermates. Although disease severity was similar in female mice, in male JNK3 null mice the day of onset and time to reach 100% incidence occurred sooner, and disease severity was increased. While glial activation in spinal cord was similar, white matter lesions were increased in JNK3 null mice. These results suggest JNK3 normally limits EAE disease in a sex-dependent manner.

Parallel development of Parkinson's-specific competencies for exercise professionals and criteria for exercise education programs.

INTRODUCTION: The Parkinson's Foundation sought to develop Parkinson's specific competencies for exercise professionals who work with people with Parkinson's (PwP). These competencies built upon exercise guidelines and professional competencies for healthy populations. The purpose of this article is to describe the development of the professional competencies, continuing education criteria, and a pilot accreditation process. METHODS: Competency development included: (1) an expert panel conducting an environmental scan, within the USA, related to exercise professional education in Parkinson's and synthesizing Parkinson's-specific exercise guidelines, (2) surveying people with Parkinson's in the USA, and (3) developing the competencies and curriculum criteria with psychometricians. A pilot accreditation process for Parkinson's exercise educational programs and continuing education courses includes an application, baseline, 6- and 12-month assessments. Activities reported here did not require ethical review. The survey was approved by NORC at the University of Chicago's Institutional Review Board (IRB). RESULTS: The environmental scan, exercise guidelines, and survey (n = 627) informed competency development. The five key condition-specific domains were: (1) foundational information on the disease and role of exercise, (2) exercise screening, (3) group and individual exercise design, (4) behavior and counseling for exercise, and (5) interprofessional communication and program development. Seven applicants were accredited as certification programs (n = 3) or continuing education courses (n = 4). DISCUSSION: The competencies, curriculum criteria, and accreditation processes support exercise professionals working with PwP. Reducing variation in the knowledge and skills of exercise professionals can improve the safe implementation and effectiveness of exercise programs, which are a critical part of integrated plan for people with Parkinson's disease (PD).

Efficacy and Feasibility of Remote Cognitive Remediation Therapy in Parkinson's Disease: A Randomized Controlled Trial.

Background: Non-motor symptoms of Parkinson's disease (PD) such as cognitive impairment are common and decrease patient quality of life and daily functioning. While no pharmacological treatments have effectively alleviated these symptoms to date, non-pharmacological approaches such as cognitive remediation therapy (CRT) and physical exercise have both been shown to improve cognitive function and quality of life in people with PD. Objective: This study aims to determine the feasibility and impact of remote CRT on cognitive function and quality of life in patients with PD participating in an organized group exercise program. Methods: Twenty-four subjects with PD recruited from Rock Steady Boxing (RSB), a non-contact group exercise program, were evaluated using standard neuropsychological and quality of life measures and randomized to the control or intervention group. The intervention group attended online CRT sessions for one hour, twice a week for 10 weeks, engaging in multi-domain cognitive exercises and group discussion. Results: Twenty-one subjects completed the study and were reevaluated. Comparing groups over time, the control group (n = 10) saw a decline in overall cognitive performance that trended towards significance (p = 0.05) and a statistically significant decrease in delayed memory (p = 0.010) and self-reported cognition (p = 0.011). Neither of these findings were seen in the intervention group (n = 11), which overwhelmingly enjoyed the CRT sessions and attested to subjective improvements in their daily lives. Conclusions: This randomized controlled pilot study suggests that remote CRT for PD patients is feasible, enjoyable, and may help slow the progression of cognitive decline. Further trials are warranted to determine the longitudinal effects of such a program.

Glucose Infusion Induced Change in Intracellular pH and Its Relationship with Tumor Glycolysis in a C6 Rat Model of Glioblastoma.

INTRODUCTION: The reliance on glycolytic metabolism is a hallmark of tumor metabolism. Excess acid and protons are produced, leading to an acidic tumor environment. Therefore, we explored the relationship between the tumor glycolytic metabolism and tissue pH by comparing 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and hyperpolarized [1-13C]pyruvate MR spectroscopy imaging (MRSI) to chemical exchange saturation transfer (CEST) MRI measurements of tumor pH. METHODS: 106 C6 glioma cells were implanted in the brains of male Wistar rats (N = 11) using stereotactic surgery. A 60-min PET acquisition after a bolus of FDG was performed at 11-13 days post implantation, and standardized uptake value (SUV) was calculated. CEST measurements were acquired the following day before and during constant infusion of glucose solution. Tumor intracellular pH (pHi) was evaluated using amine and amide concentration-independent detection (AACID) CEST MRI. The change of pHi (∆pHi) was calculated as the difference between pHi pre- and during glucose infusion. Rats were imaged immediately with hyperpolarized [1-13C]pyruvate MRSI. Regional maps of the ratio of Lac:Pyr were acquired. The correlations between SUV, Lac:Pyr ratio, and ∆pHi were evaluated using Pearson's correlation. RESULTS: A decrease of 0.14 in pHi was found after glucose infusion in tumor region. Significant correlations between tumor glycolysis measurements of Lac:Pyr and ∆pHi within the tumor (ρ = 0.83, P = 0.01) and peritumoral region (ρ = 0.76, P = 0.028) were observed. No significant correlations were found between tumor SUV and ∆pHi within the tumor (ρ = - 0.45, P = 0.17) and peritumor regions (ρ = - 0.6, P = 0.051). CONCLUSION: AACID detected the changes in pHi induced by glucose infusion. Significant correlations between tumor glycolytic measurement of Lac:Pyr and tumoral and peritumoral pHi and ∆pHi suggest the intrinsic relationship between tumor glycolytic metabolism and the tumor pH environment as well as the peritumor pH environment.

BMP action in skeletogenesis involves attenuation of retinoid signaling.

The bone morphogenetic protein (BMP) and growth and differentiation factor (GDF) signaling pathways have well-established and essential roles within the developing skeleton in coordinating the formation of cartilaginous anlagen. However, the identification of bona fide targets that underlie the action of these signaling molecules in chondrogenesis has remained elusive. We have identified the gene for the retinoic acid (RA) synthesis enzyme Aldh1a2 as a principal target of BMP signaling; prochondrogenic BMPs or GDFs lead to attenuation of Aldh1a2 expression and, consequently, to reduced activation of the retinoid signaling pathway. Consistent with this, antagonism of retinoid signaling phenocopies BMP4 action, whereas RA inhibits the chondrogenic stimulatory activity of BMP4. BMP4 also down-regulates Aldh1a2 expression in organ culture and, consistent with this, Aldh1a2 is actively excluded from the developing cartilage anlagens. Collectively, these findings provide novel insights into BMP action and demonstrate that BMP signaling governs the fate of prechondrogenic mesenchyme, at least in part, through regulation of retinoid signaling.

Use of imaging biomarkers to assess perfusion and glucose metabolism in the skeletal muscle of dystrophic mice.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease that affects 1 in 3500 boys. The disease is characterized by progressive muscle degeneration that results from mutations in or loss of the cytoskeletal protein, dystrophin, from the glycoprotein membrane complex, thus increasing the susceptibility of contractile muscle to injury. To date, disease progression is typically assessed using invasive techniques such as muscle biopsies, and while there are recent reports of the use of magnetic resonance, ultrasound and optical imaging technologies to address the issue of disease progression and monitoring therapeutic intervention in dystrophic mice, our study aims to validate the use of imaging biomarkers (muscle perfusion and metabolism) in a longitudinal assessment of skeletal muscle degeneration/regeneration in two murine models of muscular dystrophy. METHODS: Wild-type (w.t.) and dystrophic mice (weakly-affected mdx mice that are characterized by a point mutation in dystrophin; severely-affected mdx:utrn⁻/⁻ (udx) mice that lack functional dystrophin and are null for utrophin) were exercised three times a week for 30 minutes. To follow the progression of DMD, accumulation of ¹8F-FDG, a measure of glucose metabolism, in both wild-type and affected mice was measured with a small animal PET scanner (GE eXplore Vista). To assess changes in blood flow and blood volume in the hind limb skeletal muscle, mice were injected intravenously with a CT contrast agent, and imaged with a small animal CT scanner (GE eXplore Ultra). RESULTS: In hind limb skeletal muscle of both weakly-affected mdx mice and in severely-affected udx mice, we demonstrate an early, transient increase in both ¹8F-FDG uptake, and in blood flow and blood volume. Histological analysis of H&E-stained tissue collected from parallel littermates demonstrates the presence of both inflammatory infiltrate and centrally-located nuclei, a classic hallmark of myofibrillar regeneration. In both groups of affected mice, the early transient response was succeeded by a progressive decline in muscle perfusion and metabolism; this was also evidenced histologically. CONCLUSIONS: The present study demonstrates the utility of non-invasive imaging biomarkers in characterizing muscle degeneration/regeneration in murine models of DMD. These techniques may now provide a promising alternative for assessing both disease progression and the efficacy of new therapeutic treatments in patients.

Multimodality In Vivo Imaging of Perfusion and Glycolysis in a Rat Model of C6 Glioma.

PURPOSE: Chemical exchange saturation transfer MRI using an infusion of glucose (glucoCEST) is sensitive to the distribution of glucose in vivo; however, whether glucoCEST is more related to perfusion or glycolysis is still debatable. We compared glucoCEST to computed tomography perfusion (CTP), [18F] fluorodeoxyglucose positron emission tomography (FDG-PET), and hyperpolarized [1-13C] pyruvate magnetic resonance spectroscopy imaging (MRSI) in a C6 rat model of glioma to determine if glucoCEST is more strongly correlated with measurements of perfusion or glycolysis. METHODS: 106 C6 glioma cells were implanted in Wistar rat brains (n = 11). CTP (including blood volume, BV; blood flow, BF; and permeability surface area product, PS) and FDG-PET standardized uptake value (SUV) were acquired at 11 to 13 days post-surgery. GlucoCEST measurements (∆CEST) were acquired the following day on a 9.4 T MRI before and after an infusion of glucose solution. This was followed by MRSI on a 3.0 T MRI after the injection of hyperpolarized [1-13C] pyruvate to generate regional maps of the lactate:pyruvate ratio (Lac:Pyr). Pearson's correlations between glucoCEST, CTP, FDG-PET, and Lac:Pyr ratio were evaluated. RESULTS: Tumors had significantly higher SUV, BV, and PS than the contralateral brain. Tumor ∆CEST was most strongly correlated with CTP measurements of BV (ρ = 0.74, P = 0.01) and PS (ρ = 0.55, P = 0.04). No significant correlation was found between glycolysis measurements of SUV or Lac:Pyr with tumor ∆CEST. PS significantly correlated with SUV (ρ = 0.58, P = 0.005) and Lac:Pyr (ρ = 0.75, P = 0.005). BV significantly correlated with Lac:Pyr (ρ = 0.57, P = 0.02), and BF significantly correlated with SUV (ρ = 0.49, P = 0.02). CONCLUSION: This study determined that glucoCEST is more strongly correlated to measurements of perfusion than glycolysis. GlucoCEST measurements have additional confounds, such as sensitivity to changing pH, that merit additional investigation.

Fas ligand expression on T cells is sufficient to prevent prolonged airway inflammation in a murine model of asthma.

Our previous studies revealed that, in a murine model of asthma, mice that received Fas-deficient T cells developed a prolonged phase of airway inflammation, mucus production, and airway hyperreactivity that failed to resolve even 6 weeks after the last challenge. To investigate how Fas-Fas ligand (FasL) interaction occurs between T cells and other cells in vivo, Gld mice with abnormalities of the FasL signaling pathway were used. The reconstituted mice were made by transferring T cells from B6 or Gld mice to Rag(-/-) or FasL-deficient Rag(-/-) mice. We found that Rag(-/-) mice that received B6 T cells resolved the airway inflammation, whereas FasL-deficient Rag(-/-) mice that received Gld T cells developed a prolonged airway inflammation at Day 28, with decreased IFN-gamma production. Both FasL-deficient Rag(-/-) mice that received B6 T cells and Rag(-/-) mice that received Gld T cells also had completely resolved their airway inflammation by Day 28 after challenge. Interestingly, FasL-deficient Rag(-/-) mice that received Gld T cells eventually resolved airway inflammation at Day 42, with a similar level of IFN-gamma production to that of control group. These results demonstrate that FasL expression on either T cells only or non-T cells only was sufficient for the eventual resolution of airway inflammation, and the prolonged airway inflammation in FasL-deficient Rag(-/-) mice that received Gld T cells was correlated with decreased IFN-gamma production by Gld T cells.

Case Report and Literature Review: Post-Arthroscopy Pneumothorax with Anterior Decompression.

INTRODUCTION: Emergency providers should recognize that pneumothorax is a rare but serious complication of shoulder arthroscopy that may require a unique approach to decompression. CASE REPORT: We present a case of a 60-year-old female who presented to the emergency department with right-sided facial swelling, voice change, and shortness of breath three hours after an elective arthroscopic right rotator-cuff repair and was noted to have a right-sided pneumothorax. We also describe a potential novel approach to chest tube decompression that maintains shoulder adduction in patients with recently repaired rotator cuffs. CONCLUSION: Although most cases of post-arthroscopy pneumothoraces are reported in patients who received regional anesthesia or have underlying lung pathology, it can occur in lower-risk patients as was demonstrated in our case. We also suggest considering an alternative anterior approach between the midclavicular and anterior axillary lines for chest decompression in select patients when a traditional approach is less ideal due to the need to maintain shoulder immobilization postoperatively.

High-frequency ultrasound to grade disease progression in murine models of Duchenne muscular dystrophy.

OBJECTIVE: This study used high-frequency ultrasound (HFU) imaging to assess muscle damage noninvasively in a longitudinal study of 2 transgenic murine models of Duchenne muscular dystrophy (DMD): mdx, which has mutated cytoskeletal protein dystrophin; and udx, which has mutated dystrophin and lacks another cytoskeleton protein, utrophin. The mdx group was further subdivided into exercised and nonexercised subgroups to assess exercise-induced damage. METHODS: Muscle damage was assessed with HFU imaging (40 MHz) at biweekly intervals for 16 weeks. The assessment was based on the number of hyperechoic lesions, the lesion diameter, and muscle disorganization, giving a combined grade according to a 5-point scale. RESULTS: High-frequency ultrasound discriminated the severity of muscle damage between wild-type and transgenic models of DMD and between mdx and udx models. Qualitative comparisons of 3-dimensional HFU images with serial histologic sections of the skeletal muscle showed the ability of ultrasound to accurately depict changes seen in the muscle architecture in vivo. CONCLUSIONS: High-frequency ultrasound images soft tissue in mice at high contrast and spatial resolution, thereby showing that this microimaging modality has the capability to assess architectural changes in muscle fibers due to myotonic dystrophy-related diseases such as DMD.

Is there a neuropathology difference between mild cognitive impairment and dementia?

The number of studies that have investigated the neuropathology of mild cognitive impairment (MCI) is small, but growing. In this paper we have restricted our focus to the consideration of the presence and extent of postmortem findings relevant to the neuropathology of Alzheimer's disease. We have drawn from studies that have investigated the postmortem neurobiology of the brains of persons with cognitive function at the interface between unimpaired normal function and mild but definite dementia. The data derived from these studies suggest that i) the brains of persons with MCI evidence significant neuropathological and neurobiological changes relative to those without cognitive impairment; ii) in general, the neuropathological and neurobiological changes are qualitatively similar to those observed in the brains of persons with frank AD-like dementia; and iii) the neuropathological and neurobiological brain changes associated with MCI are quantitatively less than those of persons who meet criteria for dementia. Thus, the available, albeit limited, data suggests that MCI is associated with the early stages of the neurobiological and neuropathological changes that culminate in the florid lesions of AD; including the accumulation of neuritic plaques, neurofibrillary tangles, synaptic and neurotransmitter associated deficits, and significant neuronal cell death.

Infection free midline catheter implementation at a community hospital (2 years).

BACKGROUND: To reduce excess central line use and provide an option for difficult venous access patients through the introduction of a midline catheter. METHODS: Design included prospective monitoring of the implementation of a quality improvement project. The setting was a 576 bed, urban, community, nonprofit, Magnet recognized, level 3 trauma center serving primarily adult patients. Midline and peripherally inserted central catheters were inserted by a specialty nursing team; care and maintenance of all devices were provided by front line staff. RESULTS: Zero midline catheter infections were observed in the 24 months after implementation of the fixed length, power injectable device. Completion of therapy was 80%, the most frequently encountered complication was device dislodgement. CONCLUSIONS: Adoption of a vascular access nurse led midline catheter program, coupled with device selection algorithms expanded the ability to select the right device for the patient, while decreasing excess central line usage without additional increased risks to the patient.

Symptomatic Pericardial Cyst: An Atypical Case of Pleuritic Chest Pain.

Pericardial cysts were first described in 1837 as diverticula extending from the pericardium. They are rare and frequently asymptomatic. Symptomatic presentations may be similar to more common causes of chest pain or dyspnea such as acute coronary syndrome or pulmonary embolism. Emergency physicians should consider mediastinal mass, and in this case pericardial cyst, in the differential diagnosis of chest pain because of the risk for tamponade, sudden cardiac death, or other life-threatening complications. Here, we describe a novel presentation of a pericardial cyst presenting as atypical chest pain.

MagA expression attenuates iron export activity in undifferentiated multipotent P19 cells.

Magnetic resonance imaging (MRI) is a non-invasive imaging modality used in longitudinal cell tracking. Previous studies suggest that MagA, a putative iron transport protein from magnetotactic bacteria, is a useful gene-based magnetic resonance contrast agent. Hemagglutinin-tagged MagA was stably expressed in undifferentiated embryonic mouse teratocarcinoma, multipotent P19 cells to provide a suitable model for tracking these cells during differentiation. Western blot and immunocytochemistry confirmed the expression and membrane localization of MagA in P19 cells. Surprisingly, elemental iron analysis using inductively-coupled plasma mass spectrometry revealed significant iron uptake in both parental and MagA-expressing P19 cells, cultured in the presence of iron-supplemented medium. Withdrawal of this extracellular iron supplement revealed unexpected iron export activity in P19 cells, which MagA expression attenuated. The influence of iron supplementation on parental and MagA-expressing cells was not reflected by longitudinal relaxation rates. Measurement of transverse relaxation rates (R2* and R2) reflected changes in total cellular iron content but did not clearly distinguish MagA-expressing cells from the parental cell type, despite significant differences in the uptake and retention of total cellular iron. Unlike other cell types, the reversible component R2' (R2* ‒ R2) provided only a moderately strong correlation to amount of cellular iron, normalized to amount of protein. This is the first report to characterize MagA expression in a previously unrecognized iron exporting cell type. The interplay between contrast gene expression and systemic iron metabolism substantiates the potential for diverting cellular iron toward the formation of a novel iron compartment, however rudimentary when using a single magnetotactic bacterial gene expression system like magA. Since relatively few mammalian cells export iron, the P19 cell line provides a tractable model of ferroportin activity, suitable for magnetic resonance analysis of key iron-handling activities and their influence on gene-based MRI contrast.