105 results on '"Snyder CS"'
Search Results
2. Bridging the gap: gerontology and social work education.
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Snyder CS, Wesley SC, Lin MB, and May JD
- Abstract
The following study was implemented to explore the potential for a four-week curriculum module in gerontological social work education to positively impact students' practice-related knowledge concerning older adults, as well as their attitudes toward elderly persons and interest in working with them. Pertinent literature was reviewed to conceptualize the building of a gerontology curriculum module that could be integrated into a pre-existing social work course. The module's design and content were reflective of its primary goal, which was to educate students about salient aspects of social work knowledge, skill, and practice with older adults utilizing experiential methods. Data analysis revealed a significant increase in students' knowledge of aging (t=12.23, df=106, p<0.01), significant decline in students' ageist attitudes (t=3.34, df=106, p<0.01), and an increased interest in working with older adults as clients (z=3.162, p<0.05). Given the pending unprecedented growth in the older adult population and the lack of gerontology education in social work programs, this study attempts to bridge this gap. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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3. Social work with Bosnian Muslim refugee children and families: a review of the literature.
- Author
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Snyder CS, May JD, Zulcic NN, and Gabbard WJ
- Abstract
More than two million Bosnian Muslims were ethnically cleansed in the Balkan region; of these, 200,000 were killed while the others were forced to flee their homes and become refugees. This article focuses on the influence of societal and cultural values coupled with wartime experiences on the transition of Bosnian refugee families to their new countries. Consideration is given to culturally competent theoretical frameworks and practice principles social workers can use to assist Bosnian Muslim children and families in their adaptation process within their resettlement communities. [ABSTRACT FROM AUTHOR]
- Published
- 2005
4. EXPERIENCE WITH THE EXPOSURE METHOD OF BURN THERAPY
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Blocker Tg, Blocker, Snyder Cs, and Lewis
- Subjects
medicine.medical_specialty ,Burn therapy ,business.industry ,Emergency medicine ,Humans ,Medicine ,Surgery ,Burns ,business - Published
- 1951
5. Usefulness of echocardiography in infants with supraventricular tachycardia.
- Author
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Snyder CS, Fenrich AL, Friedman RA, Rosenthal G, Kertesz NJ, Snyder, Christopher S, Fenrich, Arnold L, Friedman, Richard A, Rosenthal, Geoffrey, and Kertesz, Naomi J
- Published
- 2003
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6. Pediatric nonpost-operative junctional ectopic tachycardia medical management and interventional therapies.
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Collins KK, Van Hare GF, Kertesz NJ, Law IH, Bar-Cohen Y, Dubin AM, Etheridge SP, Berul CI, Avari JN, Tuzcu V, Sreeram N, Schaffer MS, Fournier A, Sanatani S, Snyder CS, Smith RT Jr, Arabia L, Hamilton R, Chun T, and Liberman L
- Published
- 2009
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7. Co-Delivery Polymeric Poly(Lactic-Co-Glycolic Acid) (PLGA) Nanoparticles to Target Cancer Stem-Like Cells.
- Author
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Snyder CS, Repetto T, Burkhard KM, Tuteja A, and Mehta G
- Subjects
- Polylactic Acid-Polyglycolic Acid Copolymer, Polyglycolic Acid, Glycols, Sunitinib pharmacology, Lactic Acid, Paclitaxel pharmacology, Cell Line, Tumor, Drug Carriers, Antineoplastic Agents pharmacology, Nanoparticles, Neoplasms drug therapy
- Abstract
Nanoparticle drug delivery has been promoted as an effective mode of delivering antineoplastic therapeutics. However, most nanoparticle designs fail to consider the multifaceted tumor microenvironment (TME) that produce pro-tumoral niches, which are often resistant to chemo- and targeted therapies. In order to target the chemoresistant cancer stem-like cells (CSCs) and their supportive TME, in this chapter we describe a nanoparticle-based targeted co-delivery that addresses the paracrine interactions between CSC and non-cancerous mesenchymal stem cells (MSCs) in the TME. Carcinoma-activated MSCs have been shown to increase the chemoresistance and metastasis of CSC. Yet their contributions to protect the CSC TME have not yet been systematically investigated in the design of nanoparticles for drug delivery. Therefore, we describe the fabrication of degradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (120-200 nm), generated with an electrospraying process that encapsulates both a conventional chemotherapeutic, paclitaxel, and a targeted tyrosine kinase inhibitor, sunitinib, to limit MSC interactions with CSC. In the 3D hetero-spheroid model that comprises both CSCs and MSCs, the delivery of sunitinib as a free drug disrupted the MSC-protected CSC stemness and migration. Therefore, this chapter describes the co-delivery of paclitaxel and sunitinib via PLGA nanoparticles as a potential targeted therapy strategy for targeting CSCs. Overall, nanoparticles can provide an effective delivery platform for targeting CSCs and their TME together. Forthcoming studies can corroborate similar combined therapies with nanoparticles to improve the killing of CSC and chemoresistant cancer cells, thereby improving treatment efficiency., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2024
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8. Initial Counseling Prior to Palliation for Hypoplastic Left Heart Syndrome: 2021 vs 2011.
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Nandi D, Culp S, Yates AR, Hoffman TM, Juraszek AL, Snyder CS, Feltes TF, and Cua CL
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- Infant, Child, Humans, Female, Male, Pulmonary Artery surgery, Heart Ventricles, Counseling, Treatment Outcome, Retrospective Studies, Hypoplastic Left Heart Syndrome surgery, Blalock-Taussig Procedure methods, Heart Transplantation, Norwood Procedures methods
- Abstract
We sought to examine current practices and changes in practice regarding initial counseling for families of patients with hypoplastic left heart syndrome (HLHS) given the evolution of options and outcomes over time. Counseling (Norwood with Blalock-Taussig-Thomas shunt (NW-BTT), NW with right ventricle to pulmonary artery conduit (NW-RVPA), hybrid palliation, heart transplantation, or non-intervention/hospice (NI)) for patients with HLHS were queried via questionnaire of pediatric care professionals in 2021 and compared to identical questionnaire from 2011. Of 322 respondents in 2021 (39% female), 299 respondents were cardiologists (92.9%), 17cardiothoracic surgeons (5.3%), and 6 were nurse practitioners (1.9%). Respondents were largely from North America (96.9%). In 2021, NW-RVPA procedure was the preferred palliation for standard risk HLHS patient (61%) and was preferred across all US regions (p < 0.001). NI was offered as an option by 71.4% of respondents for standard risk patients and was the predominant strategy for patients with end-organ dysfunction, chromosomal abnormality, and prematurity (52%, 44%, and 45%, respectively). The hybrid procedure was preferred for low birth-weight infants (51%). In comparison to the identical 2011 questionnaire (n = 200), the NW-RVPA was endorsed more in 2021 (61% vs 52%, p = 0.04). For low birth-weight infants, hybrid procedure was more recommended than in 2011 (51% vs 21%, p < 0.001). The NW-RVPA operation is the most recommended strategy throughout the US for infants with HLHS. The hybrid procedure for low birth-weight infants is increasingly recommended. NI continues to be offered even in standard risk patients with HLHS., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2023
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9. Injectable three-dimensional tumor microenvironments to study mechanobiology in ovarian cancer.
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Horst EN, Novak CM, Burkhard K, Snyder CS, Verma R, Crochran DE, Geza IA, Fermanich W, Mehta P, Schlautman DC, Tran LA, Brezenger ME, and Mehta G
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- Alginates chemistry, Biophysics, Carcinoma, Ovarian Epithelial metabolism, Collagen chemistry, Extracellular Matrix metabolism, Female, Humans, Hydrogels chemistry, Mechanotransduction, Cellular, Sepharose, Ovarian Neoplasms metabolism, Tumor Microenvironment
- Abstract
Epithelial ovarian cancers are among the most aggressive forms of gynecological malignancies. Despite the advent of poly adenosine diphosphate-ribose polymerase (PARP) and checkpoint inhibitors, improvement to patient survival has been modest. Limited in part by clinical translation, beneficial therapeutic strategies remain elusive in ovarian cancers. Although elevated levels of extracellular proteins, including collagens, proteoglycans, and glycoproteins, have been linked to chemoresistance, they are often missing from the processes of drug- development and screening. Biophysical and biochemical signaling from the extracellular matrix (ECM) determine cellular phenotype and affect both tumor progression and therapeutic response. However, many state-of-the-art tumor models fail to mimic the complexities of the tumor microenvironment (TME) and omit key signaling components. In this article, two interpenetrating network (IPN) hydrogel scaffold platforms, comprising of alginate-collagen or agarose-collagen, have been characterized for use as 3D in vitro models of epithelial ovarian cancer ECM. These highly tunable, injection mold compatible, and inexpensive IPNs replicate the critical governing physical and chemical signaling present within the ovarian TME. Additionally, an effective and cell-friendly live-cell retrieval method has been established to recover cells post-encapsulation. Lastly, functional mechanotransduction in ovarian cancers was demonstrated by increasing scaffold stiffness within the 3D in vitro ECM models. With these features, the agarose-collagen and alginate-collagen hydrogels provide a robust TME for the study of mechanobiology in epithelial cancers. STATEMENT OF SIGNIFICANCE: Ovarian cancer is the most lethal gynecologic cancer afflicting women today. Here we present the development, characterization, and validation of 3D interpenetrating platforms to shift the paradigm in standard in vitro modeling. These models help elucidate the roles of biophysical and biochemical cues in ovarian cancer progression. The agarose-collagen and alginate-collagen interpenetrating network (IPN) hydrogels are simple to fabricate, inexpensive, and can be modified to create custom mechanical stiffnesses and concentrations of bio-adhesive motifs. Given that investigations into the roles of biophysical characteristics in ovarian cancers have provided incongruent results, we believe that the IPN platforms will be critically important to uncovering molecular drivers. We also expect these platforms to be broadly applicable to studies involving mechanobiology in solid tumors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)
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- 2022
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10. Symptomatic atrial bigeminy masquerading as congenital complete heart block.
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Mejia E, Hoyt WJ, and Snyder CS
- Abstract
Newborn male with symptomatic bradycardia initially diagnosed with complete atrioventricular block. Isoproterenol drip was initiated, and the patient was scheduled for pacemaker implantation. During the hospital course, repeat electrocardiogram and Holter monitor revealed evidence of near continuous blocked atrial bigeminy with occasional aberrantly conducted premature atrial contractions. Flecainide was started, resulting in normal sinus rhythm, and the pacemaker implantation was cancelled.
- Published
- 2021
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11. Personalized models of heterogeneous 3D epithelial tumor microenvironments: Ovarian cancer as a model.
- Author
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Horst EN, Bregenzer ME, Mehta P, Snyder CS, Repetto T, Yang-Hartwich Y, and Mehta G
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- Extracellular Matrix, Female, Humans, Neoplasm Recurrence, Local, Precision Medicine, Ovarian Neoplasms, Tumor Microenvironment
- Abstract
Intractable human diseases such as cancers, are context dependent, unique to both the individual patient and to the specific tumor microenvironment. However, conventional cancer treatments are often nonspecific, targeting global similarities rather than unique drivers. This limits treatment efficacy across heterogeneous patient populations and even at different tumor locations within the same patient. Ultimately, this poor efficacy can lead to adverse clinical outcomes and the development of treatment-resistant relapse. To prevent this and improve outcomes, it is necessary to be selective when choosing a patient's optimal adjuvant treatment. In this review, we posit the use of personalized, tumor-specific models (TSM) as tools to achieve this remarkable feat. First, using ovarian cancer as a model disease, we outline the heterogeneity and complexity of both the cellular and extracellular components in the tumor microenvironment. Then we examine the advantages and disadvantages of contemporary cancer models and the rationale for personalized TSM. We discuss how to generate precision 3D models through careful and detailed analysis of patient biopsies. Finally, we provide clinically relevant applications of these versatile personalized cancer models to highlight their potential impact. These models are ideal for a myriad of fundamental cancer biology and translational studies. Importantly, these approaches can be extended to other carcinomas, facilitating the discovery of new therapeutics that more effectively target the unique aspects of each individual patient's TME. STATEMENT OF SIGNIFICANCE: In this article, we have presented the case for the application of biomaterials in developing personalized models of complex diseases such as cancers. TSM could bring about breakthroughs in the promise of precision medicine. The critical components of the diverse tumor microenvironments, that lead to treatment failures, include cellular- and extracellular matrix- heterogeneity, and biophysical signals to the cells. Therefore, we have described these dynamic components of the tumor microenvironments, and have highlighted how contemporary biomaterials can be utilized to create personalized in vitro models of cancers. We have also described the application of the TSM to predict the dynamic patterns of disease progression, and predict effective therapies that can produce durable responses, limit relapses, and treat any minimal residual disease., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2021. Published by Elsevier Ltd.)
- Published
- 2021
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12. Sudden Death in the Young: Information for the Primary Care Provider.
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Erickson CC, Salerno JC, Berger S, Campbell R, Cannon B, Christiansen J, Moffatt K, Pflaumer A, Snyder CS, Srinivasan C, Valdes SO, Vetter VL, and Zimmerman F
- Subjects
- Adolescent, Bereavement, Cardiopulmonary Resuscitation, Cardiovascular Diseases complications, Cardiovascular Diseases diagnosis, Cardiovascular Diseases genetics, Child, Family psychology, Genetic Testing, Humans, Mass Screening, Physician's Role, Physicians, Primary Care, Primary Prevention, Risk Factors, Secondary Prevention, Death, Sudden, Cardiac prevention & control, Health Policy, Primary Health Care
- Abstract
There are multiple conditions that can make children prone to having a sudden cardiac arrest (SCA) or sudden cardiac death (SCD). Efforts have been made by multiple organizations to screen children for cardiac conditions, but the emphasis has been on screening before athletic competition. This article is an update of the previous American Academy of Pediatrics policy statement of 2012 that addresses prevention of SCA and SCD. This update includes a comprehensive review of conditions that should prompt more attention and cardiology evaluation. The role of the primary care provider is of paramount importance in the evaluation of children, particularly as they enter middle school or junior high. There is discussion about whether screening should find any cardiac condition or just those that are associated with SCA and SCD. This update reviews the 4 main screening questions that are recommended, not just for athletes, but for all children. There is also discussion about how to handle post-SCA and SCD situations as well as discussion about genetic testing. It is the goal of this policy statement update to provide the primary care provider more assistance in how to screen for life-threatening conditions, regardless of athletic status., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have no potential conflicts of interest relevant to this article to disclose., (Copyright © 2021 by the American Academy of Pediatrics.)
- Published
- 2021
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13. Improving Compliance with Dyslipidemia Screening Guidelines in a Single-center U.S. Outpatient Pediatric Cardiology Clinic.
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Pradhan S, Dodgen AL, and Snyder CS
- Abstract
The development of atherosclerotic cardiovascular disease begins in childhood. The American Academy of Pediatrics (AAP) endorsed guidelines recommending universal hyperlipidemia screening of children ages 9-11 and again at 17-21 years. An AAP Periodic Survey of Fellows demonstrated less than half of pediatricians report adherence to these guidelines. This quality improvement initiative's objective was to improve compliance with AAP hyperlipidemia guidelines in an outpatient pediatric cardiology clinic at a single academic center to 80% over a 2-month time frame., Methods: We report the results of an IRB-approved chart review at a single-center outpatient pediatric cardiology practice. We defined pediatric cardiologists' compliance as documented prior lipid screening, ordering a lipid panel, or documented recommendation for follow-up screening. Two plan-do-study-act (PDSA) cycles were undertaken. The first intervention included an informational session to provide pediatric cardiologists with AAP recommendations. The second intervention involved weekly email reminders and a statement for physicians in the electronic medical record., Results: We collected data from 600 individual charts of patients seen over 35 clinic days. We received charts before the first PDSA intervention. Baseline compliance with outpatient hyperlipidemia screening was 0%. After the first PDSA cycle, the average screening rate improved to 49%. After the second PDSA cycle, the average screening rate improved to 89%, and there was a centerline shift in the data, indicating improvement., Conclusion: We improved the pediatric cardiologists' compliance with the AAP-recommended hyperlipidemia screening guidelines from 0% to 89% through 2 intervention cycles. Further efforts may be required to sustain this change., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2020 the Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2021
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14. Loss of Consciousness in the Young Child.
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Villafane J, Miller JR, Glickstein J, Johnson JN, Wagner J, Snyder CS, Filina T, Pomeroy SL, Sexson-Tejtel SK, Haxel C, Gottlieb J, Eghtesady P, and Chowdhury D
- Subjects
- Arrhythmias, Cardiac complications, Cardiomyopathies complications, Child, Child, Preschool, Diagnosis, Differential, Heart Defects, Congenital complications, Humans, Hypertension, Pulmonary complications, Male, Seizures complications, Syncope, Vasovagal complications, Unconsciousness diagnosis, Unconsciousness etiology, Syncope diagnosis, Syncope etiology
- Abstract
In the very young child (less than eight years of age), transient loss of consciousness represents a diagnostic and management dilemma for clinicians. While most commonly benign, syncope may be due to cardiac dysfunction which can be life-threatening. It can be secondary to an underlying ion channelopathy, cardiac inflammation, cardiac ischemia, congenital heart disease, cardiomyopathy, or pulmonary hypertension. Patients with genetic disorders require careful evaluation for a cardiac cause of syncope. Among the noncardiac causes, vasovagal syncope is the most common etiology. Breath-holding spells are commonly seen in this age group. Other causes of transient loss of consciousness include seizures, neurovascular pathology, head trauma, psychogenic pseudosyncope, and factitious disorder imposed on another and other forms of child abuse. A detailed social, present, past medical, and family medical history is important when evaluating loss of consciousness in the very young. Concerning characteristics of syncope include lack of prodromal symptoms, no preceding postural changes or occurring in a supine position, after exertion or a loud noise. A family history of sudden unexplained death, ion channelopathy, cardiomyopathy, or congenital deafness merits further evaluation. Due to inherent challenges in diagnosis at this age, often there is a lower threshold for referral to a specialist.
- Published
- 2021
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15. Diagnostic Accuracy and Safety of Confirm Rx™ Insertable Cardiac Monitor in Pediatric Patients.
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Yoon JG, Fares M, Hoyt W Jr, and Snyder CS
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- Adolescent, Adult, Arrhythmias, Cardiac etiology, Child, Child, Preschool, Equipment Safety, Female, Humans, Male, Retrospective Studies, Young Adult, Arrhythmias, Cardiac diagnosis, Electrocardiography, Ambulatory instrumentation, Prostheses and Implants
- Abstract
Insertable cardiac monitors (ICM) are subcutaneously implanted devices that monitor a patient's heart rate and rhythm (Rossano in Pediatrics 112(3):e228, 2003). The diagnostic accuracy and safety of the Confirm Rx
TM (Abbott, Minneapolis, MN) ICM in pediatric patients is unknown. This is a single center, retrospective, IRB-approved review of patients ≤ 21 years implanted with Confirm RxTM ICMs from 2017 to 2020. Data collected included demographics, indications, presence of P-wave and R-wave amplitude at implantation and follow-up, number/appropriateness of transmissions pre and post implementation of SharpSenseTM technology, reprogramming to improve accuracy, time from implantation to arrhythmia detection, and complications. There were 29 patients (median age: 8 years, 59% females). P-waves were identified in all patients and average R-wave amplitude was 0.85 mV (0.26-1.03 mV). There was no significant difference in R-wave amplitude based on size (BSA ≥ 1.5 m2 : 0.76 mV, < 1.5 m2 : 0.91 mV) or congenital heart disease (+CHD: 0.86 mV, -CHD: 0.85 mV). Arrhythmias identified were the following: wide complex tachycardia (1), supraventricular tachycardia (4), bradycardia/sinus pause (3), and premature ventricular contraction (1). SharpSenseTM implementation decreased the false-positive rate in device-initiated transmissions (55.4% to 0%, p < 0.00001). Average time from implantation to arrhythmia detection was 2.63 months (range: 0-8.8). A single complication of cellulitis occurred. Confirm RxTM is appropriate for implant in pediatric patients regardless of age, BSA, or CHD. Implementation of SharpSense™ technology dramatically decreased the false-positive rate. Follow-up studies could utilize additional monitoring devices to provide analysis on potential events that the Confirm RxTM ICM missed.- Published
- 2021
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16. The HAV pattern in pediatric patients with atrioventricular node reentrant tachycardia.
- Author
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Moltedo JM, Abello MS, Doiny D, Falconi E, Majdalani MG, Diaz CJ, Macias G, and Snyder CS
- Abstract
Objectives: The purpose of this study is to assess the prevalence of a His-Atrial-Ventricular (HAV) pattern, i.e. the atrial electrogram following the His bundle -HB- electrogram and preceding the ventricular one, on the catheter placed in the His position in pediatric patients during typical atrioventricular node reentry (AVNRT)., Materials and Methods: The pediatric electrophysiology databases of two separate institutions were queried for patients with a diagnosis of AVNRT. Demographic, clinical data and the electrophysiology study (EPS) information were assessed., Results: Thirty-nine consecutive patients were included. Twenty-five were female. The average age at the time of the EPS was 12 ± 3.7 years. Induction was achieved with atrial pacing in 23, with a single atrial extra stimulus in 8 and with dual atrial extra stimuli in 8. Isoproterenol was needed to induce tachycardia in 21. Tachycardia cycle length averaged 320 ± 50 ms. An HAV pattern was present in 35 (74%) of the patients, and in 100% of the patients younger than 8., Conclusions: An HAV pattern on the catheter placed in the His position, is common in pediatric patients with AVNRT, occurring in up to 74% of the patients in this population, being more common in younger patients., Competing Interests: Declaration of competing interest The authors have no conflict of interest., (Copyright © 2020 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.)
- Published
- 2020
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17. Telehealth for Pediatric Cardiology Practitioners in the Time of COVID-19.
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Chowdhury D, Hope KD, Arthur LC, Weinberger SM, Ronai C, Johnson JN, and Snyder CS
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- Betacoronavirus, COVID-19, Child, Curriculum, Forecasting, Heart Diseases diagnosis, Humans, SARS-CoV-2, Cardiology education, Cardiology trends, Coronavirus Infections, Heart Diseases therapy, Monitoring, Physiologic methods, Monitoring, Physiologic trends, Pandemics, Pediatrics education, Pediatrics trends, Pneumonia, Viral, Remote Consultation methods, Remote Consultation trends, Telemedicine methods, Telemedicine trends
- Abstract
Due to the COVID-19 pandemic, there has been an increased interest in telehealth as a means of providing care for children by a pediatric cardiologist. In this article, we provide an overview of telehealth utilization as an extension of current pediatric cardiology practices and provide some insight into the rapid shift made to quickly implement these telehealth services into our everyday practices due to COVID-19 personal distancing requirements. Our panel will review helpful tips into the selection of appropriate patient populations and specific cardiac diagnoses for telehealth that put patient and family safety concerns first. Numerous practical considerations in conducting a telehealth visit must be taken into account to ensure optimal use of this technology. The use of adapted staffing and billing models and expanded means of remote monitoring will aid in the incorporation of telehealth into more widespread pediatric cardiology practice. Future directions to sustain this platform include the refinement of telehealth care strategies, defining best practices, including telehealth in the fellowship curriculum and continuing advocacy for technology.
- Published
- 2020
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18. Carcinoma-Associated Mesenchymal Stem Cells Promote Chemoresistance in Ovarian Cancer Stem Cells via PDGF Signaling.
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Raghavan S, Snyder CS, Wang A, McLean K, Zamarin D, Buckanovich RJ, and Mehta G
- Abstract
Within the ovarian cancer tumor microenvironment, cancer stem-like cells (CSC) interact with carcinoma associated mesenchymal stem/stromal cells (CA-MSC) through multiple secreted cytokines and growth factors. These paracrine interactions have been revealed to cause enrichment of CSC and their chemoprotection; however, it is still not known if platelet-derived growth factor (PDGF) signaling is involved in facilitating these responses. In order to probe this undiscovered bidirectional communication, we created a model of ovarian malignant ascites in the three-dimensional (3D) hanging drop heterospheroid array, with CSC and CA-MSC. We hypothesized that PDGF secretion by CA-MSC increases self-renewal, migration, epithelial to mesenchymal transition (EMT) and chemoresistance in ovarian CSC. Our results indicate that PDGF signaling in the CSC-MSC heterospheroids significantly increased stemness, metastatic potential and chemoresistance of CSC. Knockdown of PDGFB in MSC resulted in abrogation of these phenotypes in the heterospheroids. Our studies also reveal a cross-talk between PDGF and Hedgehog signaling in ovarian cancer. Overall, our data suggest that when the stromal signaling via PDGF to ovarian CSC is blocked in addition to chemotherapy pressure, the tumor cells are significantly more sensitive to chemotherapy. Our results emphasize the importance of disrupting the signals from the microenvironment to the tumor cells, in order to improve response rates. These findings may lead to the development of combination therapies targeting stromal signaling (such as PDGF and Hedgehog) that can abrogate the tumorigenic, metastatic and platinum resistant phenotypes of ovarian CSC through additional investigations.
- Published
- 2020
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19. Intracardiac radiofrequency ablation in living swine guided by polarization-sensitive optical coherence tomography.
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Zhao X, Kilinc O, Blumenthal CJ, Dosluoglu D, Jenkins MW, Snyder CS, Arruda M, and Rollins AM
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- Animals, Heart Atria diagnostic imaging, Heart Atria surgery, Swine, Tomography, Optical Coherence, Catheter Ablation, Pulmonary Veins, Radiofrequency Ablation
- Abstract
Significance: Pulmonary vein isolation with catheter-based radiofrequency ablation (RFA) is carried out frequently to treat atrial fibrillation. However, RFA lesion creation is only guided by indirect information (e.g., temperature, impedance, and contact force), which may result in poor lesion quality (e.g., nontransmural) and can lead to reoccurrence or complications., Aim: The feasibility of guiding intracardiac RFA with an integrated polarization-sensitive optical coherence tomography (PSOCT)-RFA catheter in the right atria (RA) of living swine is demonstrated., Approach: In total, 12 sparse lesions were created in the RA of three living swine using an integrated PSOCT-RFA catheter with standard ablation protocol. PSOCT images were displayed in real time to guide catheter-tissue apposition. After experiments, post-processed PSOCT images were analyzed to assess lesion quality and were compared with triphenyltetrazolium chloride (TTC) lesion quality analysis., Results: Five successful lesions identified with PSOCT images were all confirmed by TTC analysis. In two ablations, PSOCT imaging detected gas bubble formation, indicating overtreatment. Unsuccessful lesions observed with PSOCT imaging were confirmed by TTC analysis., Conclusions: The results demonstrate that the PSOCT-RFA catheter provides real-time feedback to guide catheter-tissue apposition, monitor lesion quality, and possibly help avoid complications due to overtreatment, which may enable more effective and safer RFA treatment.
- Published
- 2020
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20. Ventricular tachycardia recorded in a competitive swimmer using Confirm Rx™ loop recorder.
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Yoon JG, Snyder CS, and Hoyt WJ
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- Adolescent, Athletes, Defibrillators, Implantable, Equipment Design, Female, Humans, Syncope etiology, Syncope therapy, Tachycardia, Ventricular etiology, Tachycardia, Ventricular therapy, Treatment Outcome, Electrocardiography, Ambulatory instrumentation, Swimming, Syncope diagnosis, Tachycardia, Ventricular diagnosis
- Abstract
Conventional ambulatory heart rhythm monitoring is limited in its ability to provide rapid diagnosis of arrhythmias in athletes participating in water or high-intensity sports. This case report is of a 17-year-old female competitive swimmer who underwent loop recorder implantation with Confirm Rx™ ICM 3500 (Abbott, Minneapolis, MN) to monitor for arrhythmias during swimming. The purpose of this case report is to describe the utility of implantable loop recorders in arrhythmia diagnosis and symptom evaluation in water sport athletes.
- Published
- 2020
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21. Tumor modeling maintains diverse pathology in vitro .
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Bregenzer ME, Horst EN, Mehta P, Novak CM, Repetto T, Snyder CS, and Mehta G
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Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
- Published
- 2019
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22. Wettability Engendered Templated Self-Assembly (WETS) for the Fabrication of Biocompatible, Polymer-Polyelectrolyte Janus Particles.
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Kobaku SPR, Snyder CS, Karunakaran RG, Kwon G, Wong P, Tuteja A, and Mehta G
- Abstract
Fabrication of charged, multiphasic, polymeric micro- and nanoparticles with precise control over their composition, size, and shape is critical for developing the next generation of drug carriers for combinatorial therapies and theranostics. The addition of charged polyelectrolyte multilayers on the surface of polymeric particles can significantly improve their stability, targeting efficacy, drug-release kinetics, and their ability to encapsulate different drugs within a single particle. Many of the traditional methods for multilayer functionalization of multiphasic polymeric particles are time and energy intensive which significantly limits their scalability, and therefore therapeutic potential. In this work, we combine the bulk layer-by-layer polyelectrolyte application methodology with our previously developed technique of fabricating multiphasic polymeric particles on substrates with patterned wettability to synthesize biocompatible, monodisperse, Janus polymer-polyelectrolyte particles.
- Published
- 2019
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23. Physiologic Patient Derived 3D Spheroids for Anti-neoplastic Drug Screening to Target Cancer Stem Cells.
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Bregenzer ME, Davis C, Horst EN, Mehta P, Novak CM, Raghavan S, Snyder CS, and Mehta G
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- Drug Evaluation, Preclinical, Female, High-Throughput Screening Assays, Humans, Neoplastic Stem Cells pathology, Ovarian Neoplasms pathology, Spheroids, Cellular pathology, Tumor Microenvironment drug effects, Antineoplastic Agents pharmacology, Neoplastic Stem Cells drug effects, Spheroids, Cellular drug effects
- Abstract
In this protocol, we outline the procedure for generation of tumor spheroids within 384-well hanging droplets to allow for high-throughput screening of anti-cancer therapeutics in a physiologically representative microenvironment. We outline the formation of patient derived cancer stem cell spheroids, as well as, the manipulation of these spheroids for thorough analysis following drug treatment. Specifically, we describe collection of spheroid morphology, proliferation, viability, drug toxicity, cell phenotype and cell localization data. This protocol focuses heavily on analysis techniques that are easily implemented using the 384-well hanging drop platform, making it ideal for high throughput drug screening. While we emphasize the importance of this model in ovarian cancer studies and cancer stem cell research, the 384-well platform is amenable to research of other cancer types and disease models, extending the utility of the platform to many fields. By improving the speed of personalized drug screening and the quality of screening results through easily implemented physiologically representative 3D cultures, this platform is predicted to aid in the development of new therapeutics and patient-specific treatment strategies, and thus have wide-reaching clinical impact.
- Published
- 2019
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24. Inkjet-printed micro-calibration standards for ultraquantitative Raman spectral cytometry.
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LaLone V, Fawaz MV, Morales-Mercado J, Mourão MA, Snyder CS, Kim SY, Lieberman AP, Tuteja A, Mehta G, Standiford TJ, Raghavendran K, Shedden K, Schwendeman A, Stringer KA, and Rosania GR
- Abstract
Herein we report the development of a cytometric analysis platform for measuring the contents of individual cells in absolute (picogram) scales; this study represents the first report of Raman-based quantitation of the absolute mass - or the total amount - of multiple endogenous biomolecules within single-cells. To enable ultraquantitative calibration, we engineered single-cell-sized micro-calibration standards of known composition by inkjet-printer deposition of biomolecular components in microarrays across the surface of silicon chips. We demonstrate clinical feasibility by characterizing the compositional phenotype of human skin fibroblast and porcine alveolar macrophage cell populations in the respective contexts of Niemann-Pick disease and drug-induced phospholipidosis: two types of lipid storage disorders. We envision this microanalytical platform as the foundation for many future biomedical applications, ranging from diagnostic assays to pathological analysis to advanced pharmaco/toxicokinetic research studies.
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- 2019
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25. Imaging of Atrioventricular Nodal Conduction Tissue in Porcine Hearts Using Optical Coherence Tomography.
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Kilinc OU, Zhao X, Jenkins MW, Snyder CS, and Rollins AM
- Abstract
Optical coherence tomography (OCT) employs near-infrared light to image the microstructure of different tissues. Clinically, it has been used to image the walls of coronary arteries. In research settings, one of the applications for OCT is visualizing endocardial and subendocardial structures. The present experiment sought to determine whether OCT can identify native conduction tissues in adult porcine hearts. During the study, the right atrial endocardial surfaces of excised adult porcine hearts were exposed. The triangle of Koch was imaged with the OCT system and the conduction tissue was identified. The area was then prepared for histologic examination with Masson's trichrome stain. The results of histologic preparations and OCT images were then compared. Ultimately, nine porcine hearts were examined using this methodology. OCT imaging successfully identified subendocardial structures presumed to be the compact atrioventricular node. Histologic images of the preparations delineated the different tissue types and conduction tissue was easily identified. The location of distinctive hyporeflective areas in the OCT images correlated with the location of conduction tissue in the histology images. In light of the findings of this study, it is suggested that atrioventricular nodal tissue can be identified by OCT in freshly dissected unfixed porcine hearts. OCT images distinguished the differentiated conduction tissue in close proximity with the endocardium, myofibers, and fibrous tissue, and the success of this was verified with histology. This technology may be useful for the direct visualization of the native conduction system during procedures in the operating room and electrophysiology laboratory. Further studies with perfused tissue samples and live animal experiments are needed to better assess the efficacy of this novel application., Competing Interests: The authors report no conflicts of interest for the published content. The research reported in this project was supported by the National Institutes of Health (grant no. HL129147). All procedures were reviewed and approved by the relevant Institutional Animal Care and Use Committee., (Copyright: © 2019 Innovations in Cardiac Rhythm Management.)
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- 2019
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26. Ambulatory Arrhythmia Detection with ZIO® XT Patch in Pediatric Patients: A Comparison of Devices.
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Pradhan S, Robinson JA, Shivapour JK, and Snyder CS
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- Adolescent, Child, Female, Humans, Male, Predictive Value of Tests, Retrospective Studies, Time Factors, Arrhythmias, Cardiac diagnosis, Electrocardiography, Ambulatory methods
- Abstract
Ambulatory electrocardiogram monitoring devices can be used for 24-72 h to detect arrhythmias. A new device, the ZIO® XT Patch has cardiac monitoring capabilities that can be utilized for up to 14 days. The purpose of this study is to describe duration of ZIO use by age, and to compare its time to arrhythmia detection with the Holter monitor in a pediatric population. A single-center, retrospective review of patients < 18 years of age who underwent clinical investigation with ZIO from October 2014 to February 2016 was performed. An age-matched cohort was utilized to compare ZIO to Holter monitor results. Demographic and diagnostic data, time to first arrhythmia, and arrhythmia burden were analyzed. A total of 406 ZIO were prescribed; median age 12.7 years and 50% male subjects. Median duration of ZIO monitoring significantly increased with age (p < 0.001). 499 Holter monitors were prescribed on a statistically different age group. Arrhythmia detection rates were similar between groups, 10% (n = 42) by ZIO and 9% (n = 45) by Holter (p = NS). The majority of arrhythmias (57%) detected by ZIO were after 24 h (p < 0.0001). All arrhythmias detected by Holter monitor occurred within 24 h (p < 0.0001), mean duration of wear was 24.1 h, range 0.5-48 h. The ZIO® XT Patch may be considered as an ambulatory ECG monitor to diagnose arrhythmia in pediatric patients of all ages. Increasing patient age resulted in increasing duration of ZIO monitoring. Majority of arrhythmias detected with ZIO were identified after 24 h, which would have been missed by other short-term monitors.
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- 2019
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27. Integrated cancer tissue engineering models for precision medicine.
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Bregenzer ME, Horst EN, Mehta P, Novak CM, Raghavan S, Snyder CS, and Mehta G
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- Disease Progression, Humans, Models, Biological, Precision Medicine, Tumor Microenvironment, Neoplasms pathology, Tissue Engineering methods
- Abstract
Tumors are not merely cancerous cells that undergo mindless proliferation. Rather, they are highly organized and interconnected organ systems. Tumor cells reside in complex microenvironments in which they are subjected to a variety of physical and chemical stimuli that influence cell behavior and ultimately the progression and maintenance of the tumor. As cancer bioengineers, it is our responsibility to create physiologic models that enable accurate understanding of the multi-dimensional structure, organization, and complex relationships in diverse tumor microenvironments. Such models can greatly expedite clinical discovery and translation by closely replicating the physiological conditions while maintaining high tunability and control of extrinsic factors. In this review, we discuss the current models that target key aspects of the tumor microenvironment and their role in cancer progression. In order to address sources of experimental variation and model limitations, we also make recommendations for methods to improve overall physiologic reproducibility, experimental repeatability, and rigor within the field. Improvements can be made through an enhanced emphasis on mathematical modeling, standardized in vitro model characterization, transparent reporting of methodologies, and designing experiments with physiological metrics. Taken together these considerations will enhance the relevance of in vitro tumor models, biological understanding, and accelerate treatment exploration ultimately leading to improved clinical outcomes. Moreover, the development of robust, user-friendly models that integrate important stimuli will allow for the in-depth study of tumors as they undergo progression from non-transformed primary cells to metastatic disease and facilitate translation to a wide variety of biological and clinical studies., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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28. Cor Triatriatum: A Tale of Two Membranes.
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Rozema TK, Arruda J, and Snyder CS
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- 2019
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29. Cost-effectiveness of treating infantile haemangioma with propranolol in an outpatient setting.
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Chaturvedi K, Steinberg JS, and Snyder CS
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- Adrenergic beta-Antagonists therapeutic use, Cost-Benefit Analysis, Female, Hemangioma economics, Humans, Infant, Infant, Newborn, Male, Skin Neoplasms economics, Cost of Illness, Hemangioma drug therapy, Outpatients, Propranolol therapeutic use, Skin Neoplasms drug therapy
- Abstract
Background: Infantile haemangioma is one of the most commonly known benign vascular tumours of infancy and childhood, having an incidence of 3-10%. Most lesions regress spontaneously; however, some may require treatment owing to their clinical and cosmetic effects. Propranolol has become the treatment of choice for infantile haemangioma, but treatment protocols are largely institutional based without any specific consensus guidelines. Our aim was to evaluate the cost-effectiveness of propranolol use as inpatient versus outpatient therapy., Methods: A decision tree model was created depicting alternate strategies for initiating propranolol treatment on an inpatient versus outpatient basis combined with the option of a pretreatment echocardiogram applied to both strategies. Cost analysis was assumed to be based on treatment of haemangioma in patients who were born at term, had no chronic illnesses, a non-life-threatening location of the haemangioma, and those who were not taking any other medications that could potentiate the side effects of propranolol. A sensitivity analysis was performed to evaluate the probability of side effects., Results: The average cost incurred for inpatient treatment of infantile haemangioma was approximately $2603 for a single hospital day and increased to $2843 with the addition of an echocardiogram. The expected cost of treatment in the outpatient setting was $138, which increased to $828 after the addition of an echocardiogram., Conclusion: Treating infantile haemangioma with propranolol is more cost-effective when initiated on an outpatient basis.
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- 2018
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30. Atrioventricular junctional tachycardia with exit block in an adolescent.
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Cundiff NM, Robinson JA, Cannon BC, and Snyder CS
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- 2018
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31. Confirm RX™ Cardiac Monitor Placement in a Pediatric Patient.
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Kilinc OU, Shivapour JKL, and Snyder CS
- Abstract
We present the first known report of a pediatric implantation of the Bluetooth™-enabled Confirm RX™ insertable cardiac monitor (Abbott Laboratories, Chicago, IL, USA) in a 17-year-old patient with unexplained syncopal episodes. This case illustrates the ability to obtain immediate rhythm information from a patient using a Bluetooth™-enabled device following a minimally invasive procedure., Competing Interests: The authors report no conflicts of interest for the published content., (Copyright: © 2018 Innovations in Cardiac Rhythm Management.)
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- 2018
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32. Bilateral Ductus Arteriosus and Discontinuity of the Pulmonary Branches and Pulmonary Atresia: An Unusual Anatomy Diagnosed by Echocardiography.
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Rozema TK, Ashwath R, and Snyder CS
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- 2017
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33. Tilt table testing to diagnose pseudosyncope in the pediatric population.
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Robinson JA, Shivapour JK, and Snyder CS
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- Adolescent, Child, Child, Preschool, Diagnosis, Differential, Electrocardiography, Female, Humans, Male, Reproducibility of Results, Retrospective Studies, Young Adult, Symptom Assessment methods, Syncope, Vasovagal diagnosis, Tilt-Table Test statistics & numerical data
- Abstract
Objective: Pseudosyncope can be difficult to distinguish from true syncope. Often, pediatric patients with pseudosyncope undergo multiple tests and referrals before the appropriate diagnosis is reached. The purpose is to describe the utility of the head-up tilt table test to elicit the diagnosis of pseudosyncope in the pediatric population., Design: Retrospective chart review from November 2012 to December 2015 of patients age ≤23 years referred for 30-minute, 80-degree tilt table test. Pretest probability for pseudosyncope was high if there was no response to traditional management, atypical episodes, occurrence during undesirable exercise, or prolonged episode duration. Inductive techniques were utilized to persuade patients of the likelihood of experiencing an episode during the procedure. Pseudosyncope was confirmed when a patient had normal vital signs during their event and had reflex responses to disruptive maneuvers., Results: Tilt table testing was performed on 89 patients [median age 16 years (5-23); 26% male] with the majority (60%) being negative for pseudosyncope, including 51 true negatives and 2 false-negatives. Of the 36 patients with syncope during tilt table testing, 28 were diagnosed with vasovagal syncope and 8 with pseudosyncope [median age 16 years (15-21); 38% male]. Pseudosyncope episodes were observed immediately in 2 patients. All patients with late-onset pseudosyncope required inductive techniques prior to the recorded episode., Conclusions: Pseudosyncope can be identified during tilt table testing if inductive techniques are utilized in patients with a high index of suspicion. Disruptive maneuvers are excellent adjunctive methods to confirm the diagnosis. Tilt table testing is an effective means to identify pseudosyncope and allow appropriate diagnosis and treatment., (© 2017 Wiley Periodicals, Inc.)
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- 2017
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34. Isolated Left Subclavian Artery, Complete Atrioventricular Block, and Tricuspid Atresia in a Neonate.
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Chaturvedi K, Prasad D, Ashwath R, Strainic JP, and Snyder CS
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- Atrioventricular Block diagnosis, Atrioventricular Block surgery, Cardiac Pacing, Artificial, Computed Tomography Angiography, Echocardiography, Doppler, Color, Equipment Design, Female, Fontan Procedure, Gestational Age, Heart Block diagnosis, Heart Block surgery, Humans, Infant, Newborn, Infant, Premature, Pacemaker, Artificial, Pulmonary Artery abnormalities, Pulmonary Artery diagnostic imaging, Replantation, Subclavian Artery diagnostic imaging, Subclavian Artery surgery, Treatment Outcome, Tricuspid Atresia diagnostic imaging, Tricuspid Atresia surgery, Vascular Malformations diagnostic imaging, Vascular Malformations surgery, Abnormalities, Multiple, Atrioventricular Block congenital, Heart Block congenital, Subclavian Artery abnormalities, Tricuspid Atresia complications, Vascular Malformations complications
- Abstract
Isolated left subclavian artery is one of the rarer aortic arch anomalies. It has been associated with other congenital heart diseases, typically tetralogy of Fallot, double-outlet right ventricle, and atrial and ventricular septal defects. Its significant clinical implications include a left-to-right shunt from the vertebrobasilar system, which causes pulmonary overcirculation and subclavian steal. We present an unusual case of a premature infant who was diagnosed prenatally with congenital complete atrioventricular block and tricuspid atresia and was found to have an isolated left subclavian artery postnatally. The patient underwent implantation of a permanent single-chamber epicardial pacing system. To our knowledge, this combination of lesions has not been reported-and in our case, it influenced our surgical planning.
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- 2016
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35. Autumnal Equinox.
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Halberstadt CS
- Published
- 2016
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36. Like a Garment.
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Halberstadt CS
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- 2016
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37. Imaging the Interaction of Pancreatic Cancer and Stellate Cells in the Tumor Microenvironment during Metastasis.
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Suetsugu A, Snyder CS, Moriwaki H, Saji S, Bouvet M, and Hoffman RM
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- Animals, Cell Engineering, Cell Nucleus genetics, Cell Nucleus pathology, Cytoplasm genetics, Cytoplasm pathology, Green Fluorescent Proteins genetics, Humans, Mice, Mice, Transgenic, Neoplasm Metastasis, Pancreatic Neoplasms pathology, Molecular Imaging, Pancreatic Neoplasms genetics, Pancreatic Stellate Cells pathology, Tumor Microenvironment genetics
- Abstract
Background/aim: Pancreatic stellate cells are involved in fibrosis of pancreatic cancer termed desmoplasia, which may contribute to both pancreatic cancer growth and metastasis, as well as to drug resistance. A better understanding of pancreatic cancer-cell interactions with stellate cells is therefore critical to our ability to develop effective anti-metastatic therapeutics for pancreatic cancer., Materials and Methods: The human pancreatic cancer cell line XPA-1 was engineered to express green fluorescent protein (GFP) in the nucleus and red fluorescent protein (RFP) in the cytoplasm. Pancreatic stellate cells were engineered to express RFP. The pancreatic cancer cells and stellate cells were co-cultured and their interaction was imaged in vitro. The pancreatic cancer cells and stellate cells were then co-injected in the spleen of transgenic cyan fluorescent protein (CFP) nude mice and imaged in liver, lung and diaphragm metastasis., Results: The interaction of the pancreatic cancer cells expressing GFP in the nucleus and RFP in the cytoplasm and stellate cells expressing RFP was first imaged in vitro. The intimate relationship between the two cell types could be seen. Three hours after splenic co-injection, dual-color pancreatic cancer cells and pancreatic stellate cells were found distributed in the host liver. By 28 days after splenic co-injection of the pancreatic cancer and stellate cells, liver metastases were observed in host CFP nude mice. Metastases were also observed in the lung and diaphragm. Stellate cells were observed along with the pancreatic cancer cells at all metastatic sites suggesting that stellate cells may be necessary for metastasis. With high-resolution intravital imaging afforded by the Olympus FV1000 confocal microscope, the interaction of the dual-colored pancreatic cancer cells and the RFP-expressing pancreatic stellate cells could be clearly imaged in the liver and other metastases, further suggesting that stellate cells participate in metastasis formation., Conclusion: Pancreatic cancer cells and stellate stem cells form a very close relationship and accompany each other to distant metastatic sties. Our hypothesis is that pancreatic stellate cells form a niche for metastasis of pancreatic cancer., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)
- Published
- 2015
38. T-wave reversion in pediatric patients during exercise stress testing.
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Hoyt WJ Jr, Ardoin KB, Cannon BC, and Snyder CS
- Subjects
- Adolescent, Child, Female, Humans, Male, Retrospective Studies, Electrocardiography, Exercise Test, Heart physiology
- Abstract
Objective: T-wave inversion in lateral electrocardiogram (ECG) leads (II, III, aVF, V4 -V6 ) is suspicious of cardiac pathology in pediatric patients, though many are found to have structurally normal hearts. The purpose of this study is to evaluate T-wave response during exercise stress testing (EST) in pediatric patients with structurally normal hearts and lateral-lead T-wave inversion on resting ECG., Design: An IRB-approved, retrospective review of EST databases at two centers identified patients with lateral-lead T-wave inversion on resting ECG. Inclusion criteria were normal exam and echocardiogram, absence of anginal chest pain, and age <18 years. All patients underwent treadmill or cycle ergometer EST. Data recorded included demographics, echocardiogram results, baseline ECG, EST method, peak heart rate and metabolic equivalents (METs), and heart rate and METs at T-wave reversion. T-wave reversion was considered complete if T-waves reverted in all leads, partial if reversion occurred in only some leads, and none if no reversion occurred., Results: The search identified 14 patients: nine females and five males (10 Caucasians and four African Americans) and an average age of 16 (range 12-18) years. Complete T-wave reversion occurred in 11 (79%) patients, partial in two (14%), and none in one (7%). Reversion occurred in both genders, ethnicities, and EST methods. No complications occurred during EST; no adverse outcomes occurred during 2-year follow-up., Conclusions: EST in pediatric patients with lateral-lead T-wave inversion on resting ECG and structurally and functionally normal hearts resulted in either complete or partial T-wave reversion in the vast majority of patients., (© 2014 Wiley Periodicals, Inc.)
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- 2015
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39. A dual-color genetically engineered mouse model for multispectral imaging of the pancreatic microenvironment.
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Snyder CS, Harrington AR, Kaushal S, Mose E, Lowy AM, Hoffman RM, and Bouvet M
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- Animals, Diagnostic Imaging methods, Disease Models, Animal, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Integrases genetics, Integrases metabolism, Luminescent Proteins genetics, Mice, Mice, 129 Strain, Mice, Inbred C57BL, Mice, Transgenic, Microscopy, Confocal, Pancreatic Neoplasms diagnosis, Pancreatic Neoplasms genetics, Plant Proteins genetics, Plant Proteins metabolism, Reproducibility of Results, Sensitivity and Specificity, Time Factors, Trans-Activators genetics, Trans-Activators metabolism, Red Fluorescent Protein, Luminescent Proteins metabolism, Pancreatic Neoplasms metabolism, Tumor Microenvironment
- Abstract
Objectives: To develop a mouse model for multispectral fluorescence imaging of the pancreas and pancreatic microenvironment., Methods: Cre/loxP technology was used to develop this model. We crossed mT/mG indicator mice, engineered to constitutively express a conditional tdTomato transgene that converts to green fluorescent protein (GFP) expression after exposure to Cre recombinase, with Pdx1-Cre transgenic mice. To characterize this model for studies of pancreas biology, we performed bright light and fluorescence imaging of body cavities and intact organs and confocal microscopy of pancreata from offspring of Pdx1-Cre and mT/mG crosses., Results: Pdx1-Cre-mT/mG mice demonstrated bright GFP expression within the pancreas and duodenum and intense tdTomato expression in all other organs. Green fluorescent protein expression was mosaic in Pdx1-Cre-mT/mG pancreata, with most showing extensive conversion from tdTomato to GFP expression within the epithelial-derived elements of the pancreatic parenchyma. Because both GFP and tdTomato are membrane targeted, individual cell borders were clearly outlined in confocal images of mT/mG pancreata., Conclusions: This mouse model enables multispectral fluorescence imaging of individual cells and cell processes at the microscopic level of the pancreatic microenvironment; it should prove valuable for a variety of fluorescence imaging studies, ranging from pancreatic development to pancreatic cancer biology.
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- 2013
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40. Induction of atrial fibrillation with adenosine during a transesophageal electrophysiology study to risk stratify a patient with asymptomatic ventricular preexcitation.
- Author
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Hoyt WJ Jr, Thomas PE, and Snyder CS
- Subjects
- Accessory Atrioventricular Bundle, Action Potentials, Adolescent, Asymptomatic Diseases, Atrial Fibrillation physiopathology, Cardiac Pacing, Artificial, Humans, Incidental Findings, Male, Pre-Excitation Syndromes complications, Pre-Excitation Syndromes physiopathology, Predictive Value of Tests, Refractory Period, Electrophysiological, Risk Assessment, Risk Factors, Time Factors, Adenosine, Athletes, Atrial Fibrillation diagnosis, Death, Sudden, Cardiac etiology, Electrophysiologic Techniques, Cardiac, Heart Conduction System physiopathology, Pre-Excitation Syndromes diagnosis
- Abstract
An asymptomatic adolescent male athlete was incidentally found to have ventricular preexcitation on electrocardiogram during a sports preparticipation physical. A transesophageal electrophysiology study (TEEPS) was performed after an exercise stress test failed to delineate the patient's risk of sudden cardiac death. The TEEPS was favored in this case over a transvenous electrophysiology study due to reduced invasiveness. The goal of the TEEPS was to place the patient into atrial fibrillation (AFib) and evaluate the shortest preexcited RR interval during AFib, thereby assessing the risk of his accessory pathway. Conventional pacing modalities were unable to induce AFib. During atrial burst pacing, adenosine was then administered, which successfully induced AFib. This case highlights adenosine's potential to induce atrial fibrillation during transesophageal electrophysiology studies when atrial pacing alone was unable to do so., (© 2012 Wiley Periodicals, Inc.)
- Published
- 2013
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41. The American Academy of Pediatrics Section on Cardiology Meeting.
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Snyder CS and Moodie D
- Subjects
- Humans, Societies, Medical, Biomedical Research, Cardiology, Pediatrics
- Published
- 2013
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42. Fluorescence-guided surgery of human colon cancer increases complete resection resulting in cures in an orthotopic nude mouse model.
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Metildi CA, Kaushal S, Snyder CS, Hoffman RM, and Bouvet M
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- Animals, Antigens, Neoplasm immunology, Cell Line, Tumor, Colorectal Neoplasms immunology, Colorectal Neoplasms pathology, Disease-Free Survival, Female, Fluorescent Antibody Technique, Humans, Kaplan-Meier Estimate, Mice, Mice, Nude, Secondary Prevention, Treatment Outcome, Colorectal Neoplasms surgery, Digestive System Surgical Procedures methods, Disease Models, Animal, Optical Imaging methods, Transplantation, Heterologous
- Abstract
Background: We inquired if fluorescence-guided surgery (FGS) could improve surgical outcomes in fluorescent orthotopic nude mouse models of human colon cancer., Methods: We established fluorescent orthotopic mouse models of human colon cancer expressing a fluorescent protein. Tumors were resected under bright light surgery (BLS) or FGS. Pre- and post-operative images with the OV-100 Small Animal Imaging System (Olympus Corp, Tokyo Japan) were obtained to assess the extent of surgical resection., Results: All mice with primary tumor that had undergone FGS had complete resection compared with 58% of mice in the BLS group (P = 0.001). FGS resulted in decreased recurrence compared with BLS (33% versus 62%, P = 0.049) and lengthened disease-free median survival from 9 to >36 wk. The median overall survival increased from 16 wk in the BLS group to 31 weeks in the FGS group. FGS resulted in a cure in 67% of mice (alive without evidence of tumor at >6 mo after surgery) compared with only 37% of mice that underwent BLS (P = 0.049)., Conclusions: Surgical outcomes in orthotopic nude mouse models of human colon cancer were significantly improved with FGS. The present study can be translated to the clinic by various effective methods of fluorescently labeling tumors., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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43. Atrial fibrillation induction by transesophageal electrophysiology studies in patients with asymptomatic ventricular preexcitation.
- Author
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Hoyt WJ Jr, Thomas PE, DeSena HC, Steinberg JS, Harmon DE, and Snyder CS
- Subjects
- Adolescent, Atrial Fibrillation complications, Child, Child, Preschool, Death, Sudden, Cardiac prevention & control, Electrophysiologic Techniques, Cardiac methods, Female, Humans, Male, Pre-Excitation Syndromes complications, Retrospective Studies, Risk Assessment, Atrial Fibrillation physiopathology, Pre-Excitation Syndromes physiopathology
- Abstract
Objective: Ventricular preexcitation is a conduction abnormality caused by an accessory pathway bridging the atria and ventricles. If the accessory pathway conducts rapidly during atrial fibrillation (AFib), sudden death may result. The purpose of this study was to determine the ability of transesophageal electrophysiology studies (TEEPS) to induce AFib in pediatric patients with asymptomatic ventricular preexcitation (aVPE)., Design: A retrospective review of patients with aVPE who had a TEEPS was conducted. Inclusion criteria were evidence of ventricular preexcitation on electrocardiogram; age <18 years; and no history of tachycardia, palpitations, or syncope. Data gathered included age, weight, height, form of sedation, and TEEPS results. If AFib was induced, patients were classified as at risk of sudden death if the shortest preexcited RR interval during AFib was <250 ms or no risk if ≥ 250 ms., Results: A total of 26 patients met the inclusion criteria, with average age of 11.9 years, weight of 48.9 kg, and height of 149.2 cm. During the procedure, nine patients underwent conscious sedation (34.6%), and 17 underwent general anesthesia (65.4%). AFib was induced in 23 patients (88.5%), of whom 17 (73.9%) had no risk and six (26.1%) had risk. No statistical differences were noted in age, weight, height, or form of sedation when comparisons were made between AFib induction and no AFib induction., Conclusions: TEEPS induced AFib in 88.5% of patients. Age, weight, height, and form of sedation had no effect upon AFib inducibility. TEEPS is an effective modality to induce AFib in pediatric patients with aVPE., (© 2012 Wiley Periodicals, Inc.)
- Published
- 2013
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44. Detection of colon cancer metastases with fluorescence laparoscopy in orthotopic nude mouse models.
- Author
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Menen RS, Kaushal S, Snyder CS, Talamini MA, Hoffman RM, and Bouvet M
- Subjects
- Animals, Disease Models, Animal, Female, Fluorescence, Humans, Mice, Mice, Nude, Neoplasm Transplantation, Colonic Neoplasms pathology, Laparoscopy methods
- Abstract
Objective: To improve detection of colon cancer metastases using fluorescence laparoscopy (FL)., Design: An orthotopic mouse model of human colon cancer was established by intracecal injection of HCT-116 human colon cancer cells expressing green fluorescent protein into 12 mice. One group modeled early disease and the second modeled late metastatic disease. For the early-disease model, 2 weeks after implantation, 6 mice underwent 2 modalities of laparoscopy: bright field laparoscopy (BL) and FL. The number of metastases identified within each of the 4 abdominal quadrants was recorded with both laparoscopy modalities. This process was repeated in the late-metastatic disease group 4 weeks after implantation. All animals were then humanely sacrificed and imaged using open fluorescence laparoscopy (OL) as a positive control to identify metastases., Setting: Basic science laboratory., Participants: Twelve female, 6-week-old nude mice., Interventions: Detection of tumor foci by FL compared with BL., Main Outcome Measures: Number of tumors identified in each quadrant. RESULTS Fluorescence laparoscopy enabled superior visualization of colon cancer metastases compared with BL in the early (P = .03) and late (P = .002) models of colon cancer. Compared with OL, BL was significantly inferior in the early (P = .04) and late (P < .001) groups. Fluorescence laparoscopy was not significantly different from OL in the early (P = .85) or late (P = .46) group. Thus, FL allowed identification of micrometastases that could not be distinguished from surrounding tissue using BL., Conclusions: The use of FL enables identification of metastases that could not be visualized using standard laparoscopy. This report illustrates the important clinical potential for FL in the surgical treatment of cancer.
- Published
- 2012
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45. Tumor-specific fluorescence antibody imaging enables accurate staging laparoscopy in an orthotopic model of pancreatic cancer.
- Author
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Tran Cao HS, Kaushal S, Metildi CA, Menen RS, Lee C, Snyder CS, Messer K, Pu M, Luiken GA, Talamini MA, Hoffman RM, and Bouvet M
- Subjects
- Animals, Cell Line, Tumor, Female, Fluorescent Dyes, Humans, Mice, Mice, Nude, Pancreatic Neoplasms secondary, Pancreatic Neoplasms surgery, Predictive Value of Tests, Sensitivity and Specificity, Time Factors, Antibodies, Monoclonal, Carcinoembryonic Antigen immunology, Fluorescent Antibody Technique, Laparoscopy, Neoplasm Staging methods, Pancreatic Neoplasms immunology, Pancreatic Neoplasms pathology
- Abstract
Background/aims: Laparoscopy is important in staging pancreatic cancer, but false negatives remain problematic. Making tumors fluorescent has the potential to improve the accuracy of staging laparoscopy., Methodology: Orthotopic and carcinomatosis models of pancreatic cancer were established with BxPC-3 human pancreatic cancer cells in nude mice. Alexa488-antiCEA conjugates were injected via tail vein 24 hours prior to laparoscopy. Mice were examined under bright field laparoscopic (BL) and fluorescence laparoscopic (FL) modes. Outcomes measured included time to identification of primary tumor for the orthotopic model and number of metastases identified within 2 minutes for the carcinomatosis model., Results: FL enabled more rapid and accurate identification and localization of primary tumors and metastases than BL. Using BL took statistically significantly longer time than FL (p<0.0001, fold change and 95% CI for BL vs. FL: 8.12 (4.54,14.52)). More metastatic lesions were detected and localized under FL compared to BL and with greater accuracy, with sensitivities of 96% vs. 40%, respectively, when compared to control. FL was sensitive enough to detect metastatic lesions <1mm., Conclusions: The use of fluorescence laparoscopy with tumors labeled with fluorophore-conjugated anti-CEA antibody permits rapid detection and accurate localization of primary and metastatic pancreatic cancer in an orthotopic model. The results of the present report demonstrate the future clinical potential of fluorescence laparoscopy.
- Published
- 2012
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46. Fluorescence-guided surgery allows for more complete resection of pancreatic cancer, resulting in longer disease-free survival compared with standard surgery in orthotopic mouse models.
- Author
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Metildi CA, Kaushal S, Hardamon CR, Snyder CS, Pu M, Messer KS, Talamini MA, Hoffman RM, and Bouvet M
- Subjects
- Animals, Disease Models, Animal, Disease-Free Survival, Female, Humans, Mice, Mice, Nude, Neoplasm Transplantation, Tumor Cells, Cultured, Red Fluorescent Protein, Luminescent Proteins analysis, Pancreatectomy methods, Pancreatic Neoplasms chemistry, Pancreatic Neoplasms surgery
- Abstract
Background: Negative surgical margins are vital to achieve cure and prolong survival in patients with pancreatic cancer. We inquired if fluorescence-guided surgery (FGS) could improve surgical outcomes and reduce recurrence rates in orthotopic mouse models of human pancreatic cancer., Study Design: A randomized active-control preclinical trial comparing bright light surgery (BLS) to FGS was used. Orthotopic mouse models of human pancreatic cancer were established using the BxPC-3 pancreatic cancer cell line expressing red fluorescent protein (RFP). Two weeks after orthotopic implantation, tumors were resected with BLS or FGS. Pre- and postoperative images were obtained with the OV-100 Small Animal Imaging System to assess completeness of surgical resection in real time. Postoperatively, noninvasive whole body imaging was done to assess recurrence and follow tumor progression. Six weeks postoperatively, mice were sacrificed to evaluate primary pancreatic and metastatic tumor burden at autopsy., Results: A more complete resection of pancreatic cancer was achieved using FGS compared with BLS: 98.9% vs 77.1%, p = 0.005. The majority of mice undergoing BLS (63.2%) had evidence of gross disease with no complete resections; 20% of mice undergoing FGS had complete resection and an additional 75% had only minimal residual disease (p = 0.0001). The mean postoperative tumor burden was significantly less with FGS compared with BLS: 0.08 ± 0.06 mm(2) vs 2.64 ± 0.63 mm(2), p = 0.001. The primary tumor burden at termination was significantly less with FGS compared with BLS: 19.3 ± 5.3 mm(2) vs 6.2 ± 3.6 mm(2), p = 0.048. FGS resulted in significantly longer disease-free survival than BLS (p = 0.02, hazard ratio = 0.39, 95% CI 0.17, 0.88)., Conclusions: Surgical outcomes were improved in pancreatic cancer using fluorescence-guidance. This novel approach has significant potential to improve surgical treatment of cancer., (Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
47. An LED light source and novel fluorophore combinations improve fluorescence laparoscopic detection of metastatic pancreatic cancer in orthotopic mouse models.
- Author
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Metildi CA, Kaushal S, Lee C, Hardamon CR, Snyder CS, Luiken GA, Talamini MA, Hoffman RM, and Bouvet M
- Subjects
- Animals, Equipment Design, Female, Humans, Mice, Mice, Nude, Neoplasm Transplantation, Neoplasms, Experimental secondary, Pancreatic Neoplasms secondary, Reproducibility of Results, Tumor Cells, Cultured transplantation, Fluorescence, Fluorescent Dyes, Laparoscopy methods, Lighting instrumentation, Neoplasms, Experimental diagnosis, Pancreatic Neoplasms diagnosis
- Abstract
Background: The aim of this study was to improve fluorescence laparoscopy of pancreatic cancer in an orthotopic mouse model with the use of a light-emitting diode (LED) light source and optimal fluorophore combinations., Study Design: Human pancreatic cancer models were established with fluorescent FG-RFP, MiaPaca2-GFP, BxPC-3-RFP, and BxPC-3 cancer cells implanted in 6-week-old female athymic mice. Two weeks postimplantation, diagnostic laparoscopy was performed with a Stryker L9000 LED light source or a Stryker X8000 xenon light source 24 hours after tail-vein injection of CEA antibodies conjugated with Alexa 488 or Alexa 555. Cancer lesions were detected and localized under each light mode. Intravital images were also obtained with the OV-100 Olympus and Maestro CRI Small Animal Imaging Systems, serving as a positive control. Tumors were collected for histologic analysis., Results: Fluorescence laparoscopy with a 495-nm emission filter and an LED light source enabled real-time visualization of the fluorescence-labeled tumor deposits in the peritoneal cavity. The simultaneous use of different fluorophores (Alexa 488 and Alexa 555), conjugated to antibodies, brightened the fluorescence signal, enhancing detection of submillimeter lesions without compromising background illumination. Adjustments to the LED light source permitted simultaneous detection of tumor lesions of different fluorescent colors and surrounding structures with minimal autofluorescence., Conclusions: Using an LED light source with adjustments to the red, blue, and green wavelengths, it is possible to simultaneously identify tumor metastases expressing fluorescent proteins of different wavelengths, which greatly enhanced the signal without compromising background illumination. Development of this fluorescence laparoscopy technology for clinical use can improve staging and resection of pancreatic cancer., (Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
48. Management of atrial tachycardia in the newborn with enterovirus myocarditis.
- Author
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Petroni DH, Yang SG, Kattash MM, and Snyder CS
- Abstract
Neonatal enterovirus myocarditis is a rare but serious infection that is often an underrecognized cause of cardiovascular collapse. Enterovirus myocarditis in patients with such collapse should be suspected when signs of congestive heart failure and tachyarrhythmia are present. The majority of reported electrical disturbances associated with enterovirus myocarditis are ventricular in origin, but the infection can present as atrial tachyarrhythmia. Atrial tachyarrhythmias associated with enterovirus myocarditis are difficult to manage because of their resistance to conventional antiarrhythmic therapy. We present 2 cases of neonates with atrial tachycardia associated with enterovirus myocarditis who responded to a combination of amiodarone and flecainide.
- Published
- 2012
49. Identifying arrhythmias in adults with congenital heart disease by 24-h ambulatory electrocardiography.
- Author
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Rodriguez FH, Moodie DS, Neeland M, Adams GJ, and Snyder CS
- Subjects
- Adolescent, Adult, Aged, Arrhythmias, Cardiac epidemiology, Arrhythmias, Cardiac etiology, Electrocardiography, Female, Follow-Up Studies, Heart Defects, Congenital diagnosis, Humans, Incidence, Male, Middle Aged, Reproducibility of Results, Retrospective Studies, Risk Factors, United States epidemiology, Young Adult, Arrhythmias, Cardiac diagnosis, Electrocardiography, Ambulatory methods, Heart Defects, Congenital complications
- Abstract
Adults with congenital heart disease (CHD) are at risk for the development of arrhythmias. This study aimed to assess the incidence of unsuspected arrhythmias among adults with CHD identified on electrocardiograms (ECGs) and 24-h ambulatory electrocardiographic monitoring (Holter monitoring). A review of the cardiology database at the authors' institution from July 2004 through December 2007 identified all clinic patients 18 years old or older who had a recent ECG and Holter monitoring. Data collection included diagnosis, ECG and Holter monitoring results, arrhythmias, and the presence or absence of symptoms. The review identified 140 patients. Analysis of the ECGs showed that 15% of the patients had an arrhythmia. These arrhythmias consisted of ectopy (6%), supraventricular tachycardia (SVT) (3%), pacemaker issues (2%), and previously unrecognized atrioventricular block (AVB) (1%). The majority of the patients with arrhythmias were asymptomatic (76%). Analysis of the Holter monitoring results showed that 31% of the patients had arrhythmias consisting of ectopy (17%), SVT (12%), ventricular tachycardia (7%), high-grade AVB (5%), and pacemaker issues (3%). Of the patients with arrhythmias, 80% were asymptomatic. Among the patients without arrhythmias on ECG, 26% had arrhythmias noted on Holter monitoring. Of the patients with multiple Holter monitorings performed, 34% had a new arrhythmia noted on repeat monitoring. In conclusion, arrhythmias were present in a significant number of adults with CHD, but the majority were asymptomatic. Among adults with CHD, even those with normal ECGs, arrhythmias were frequently detected on Holter monitoring. In addition, repeat Holter monitoring may identify significant arrhythmias over time.
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- 2012
- Full Text
- View/download PDF
50. Intermittent cyanosis years after a Mustard repair for dextro-transposition of the great arteries.
- Author
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Saraf A, Franklin WJ, Snyder CS, Fraser CD Jr, and Salazar JD
- Subjects
- Adult, Coronary Angiography, Cyanosis diagnosis, Cyanosis surgery, Echocardiography, Transesophageal, Female, Humans, Prosthesis-Related Infections diagnosis, Prosthesis-Related Infections etiology, Reoperation, Sick Sinus Syndrome etiology, Thrombosis diagnosis, Thrombosis etiology, Time Factors, Treatment Outcome, Cardiac Surgical Procedures adverse effects, Cyanosis etiology, Pacemaker, Artificial adverse effects, Prosthesis-Related Infections surgery, Sick Sinus Syndrome surgery, Thrombosis surgery, Transposition of Great Vessels surgery
- Abstract
A 28-year-old woman, who as an infant had undergone the Mustard atrial switch procedure for dextro-transposition of the great arteries, presented with a baffle leak and consequent intermittent cyanosis. In addition, an occlusive thrombus had formed in the systemic venous baffle after a failed attempt to remove infected pacemaker leads. Corrective surgery was successful. In addition to the case of our patient, we discuss long-term sequelae of the atrial switch procedure that present challenges in patient care.
- Published
- 2012
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