115 results on '"Collins MM"'
Search Results
2. HHEX is a transcriptional regulator of the VEGFC/FLT4/PROX1 signaling axis during vascular development
- Author
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Gauvrit, S, Villasenor, A, Strilic, B, Kitchen, P, Collins, MM, Marín-Juez, R, Guenther, S, Maischein, HM, Fukuda, N, Canham, MA, Brickman, JM, Bogue, CW, and Stainier, DYR
- Abstract
Formation of the lymphatic system requires the coordinated expression of several key regulators: vascular endothelial growth factor C (VEGFC), its receptor FLT4, and a key transcriptional effector, PROX1. Yet, how expression of these signaling components is regulated remains poorly understood. Here, using a combination of genetic and molecular approaches, we identify the transcription factor hematopoietically expressed homeobox (HHEX) as an upstream regulator of VEGFC, FLT4, and PROX1 during angiogenic sprouting and lymphatic formation in vertebrates. By analyzing zebrafish mutants, we found that hhex is necessary for sprouting angiogenesis from the posterior cardinal vein, a process required for lymphangiogenesis. Furthermore, studies of mammalian HHEX using tissue-specific genetic deletions in mouse and knockdowns in cultured human endothelial cells reveal its highly conserved function during vascular and lymphatic development. Our findings that HHEX is essential for the regulation of the VEGFC/FLT4/PROX1 axis provide insights into the molecular regulation of lymphangiogenesis.
- Published
- 2018
3. Dietary patterns in middle-aged Irish men and women defined by cluster analysis
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Villegas, R, primary, Salim, A, additional, Collins, MM, additional, Flynn, A, additional, and Perry, IJ, additional
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- 2004
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4. Human papillomavirus infection and the HPV vaccine: what are the facts?
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Conner MR and Collins MM
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- 2008
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5. Morphological assessment of the soft palate in habitual snoring using image analysis.
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Reda M, Sims AJ, Collins MM, McKee GJ, Marshall H, Kelly PJ, and Wilson JA
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- 1999
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6. Medical malpractice implications of PSA testing for early detection of prostate cancer.
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Collins MM, Fowler FJ Jr., Roberts RG, Oesterling JE, Annas GJ, and Barry MJ
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- 1997
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7. Early detection of prostate cancer. Serendipity strikes again.
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Collins MM, Ransohoff DF, Barry MJ, McNaughton Collins, M, Ransohoff, D F, and Barry, M J
- Abstract
An underappreciated characteristic of prostate cancer screening is that it may detect some prostate cancers solely by serendipity or chance. Serendipity, previously described in the detection of colonic neoplasms, could affect prostate cancer detection when a screening test result is abnormal for reasons other than the presence of prostate cancer, but prostate cancer is coincidentally detected during the subsequent evaluation of the abnormal screening result. We reviewed published articles about prostate cancer screening, searching for evidence of serendipity. We defined serendipity in digital rectal examination (DRE) screening as the discovery of a prostate cancer by the random biopsy of an area of the prostate gland other than the palpable suspicious area that prompted the biopsy. We defined serendipity in prostate-specific antigen (PSA) screening as the discovery of a prostate cancer by the random biopsy of a nonpalpable (stage T1c) prostate cancer less than 1.0 cm3 in volume, since tumors less than 1.0 cm3 are generally too small to cause elevated PSA levels. We found that serendipity may be responsible for the detection of more than one quarter of apparently DRE-detected prostate cancers and up to one quarter of apparently PSA-detected cancers. Additionally, serendipity played a larger role in the detection of smaller tumors that are common but of uncertain clinical significance. We conclude that serendipity-detected prostate cancers contribute to an overestimation of the true information value of DRE and PSA screening. Whether serendipity is advantageous in prostate cancer screening depends on the as yet uncertain outcomes for men with smaller prostate cancers. However, given our estimates of the potential magnitude of the impact of serendipity, the currently popular DRE- and PSA-based screening strategy may not be optimal. If smaller prostate cancers are important, then we are not finding enough; if they are unimportant, then we are finding too many that we may feel compelled to treat aggressively. [ABSTRACT FROM AUTHOR]
- Published
- 1997
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8. Controversies in prostate cancer screening. Analogies to the early lung cancer screening debate.
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Collins MM, Barry MJ, Collins, M M, and Barry, M J
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BONE morphogenetic proteins , *BONE regeneration , *BONE resorption , *GROWTH factors , *DENTAL implants , *LONGITUDINAL method , *MAXILLA , *PERIODONTAL disease , *RECOMBINANT proteins , *TREATMENT effectiveness - Abstract
The current debate regarding early detection and aggressive treatment of prostate cancer is fueled by the absence of controlled studies defining the risks and benefits of prostate cancer screening, and by the lack of adequately powered trials demonstrating the benefit of curative treatment for early-stage prostate cancer. Pending the results of clinical trials in 10 to 15 years, advocates of early detection of prostate cancer with digital rectal examination and prostate-specific antigen have compared prostate cancer screening with the effective strategy of breast cancer screening, implying that prostate cancer screening should similarly reduce cancer mortality. They have also cited the high burden of disease, the acceptable operating characteristics of digital rectal examination and prostate-specific antigen, a stage shift among cases detected by screening, and the theoretical curability of early-stage disease as sufficient reasons to proceed with screening. These arguments, however, are reminiscent of earlier arguments in favor of lung cancer screening with chest x-ray examination and sputum cytology, a practice ultimately proven ineffective in clinical trials. We reviewed published articles on lung and prostate cancer screening and identified many parallels. While prostate cancer screening may one day prove effective, analogies between the current prostate cancer screening controversy and the older lung cancer screening debate should inject some caution regarding widespread dissemination of prostate cancer screening without experimental evidence that such screening does more good than harm. [ABSTRACT FROM AUTHOR]
- Published
- 1996
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9. Postural stability of preoperative acoustic neuroma patients assessed by sway magnetometry: are they unsteady?
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Collins MM, Johnson IJM, Clifford E, Birchall JP, and O'Donoghue GM
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- 2003
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10. Depleting myeloid-biased haematopoietic stem cells rejuvenates aged immunity.
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Ross JB, Myers LM, Noh JJ, Collins MM, Carmody AB, Messer RJ, Dhuey E, Hasenkrug KJ, and Weissman IL
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- Animals, Female, Male, Mice, B-Lymphocytes cytology, B-Lymphocytes immunology, Inflammation immunology, Inflammation pathology, Lymphopoiesis, Myelopoiesis, Phenotype, T-Lymphocytes cytology, T-Lymphocytes immunology, Viruses immunology, Adaptive Immunity immunology, Aging immunology, Cell Lineage, Hematopoietic Stem Cells cytology, Hematopoietic Stem Cells immunology, Lymphocytes cytology, Lymphocytes immunology, Myeloid Cells cytology, Myeloid Cells immunology, Rejuvenation
- Abstract
Ageing of the immune system is characterized by decreased lymphopoiesis and adaptive immunity, and increased inflammation and myeloid pathologies
1,2 . Age-related changes in populations of self-renewing haematopoietic stem cells (HSCs) are thought to underlie these phenomena3 . During youth, HSCs with balanced output of lymphoid and myeloid cells (bal-HSCs) predominate over HSCs with myeloid-biased output (my-HSCs), thereby promoting the lymphopoiesis required for initiating adaptive immune responses, while limiting the production of myeloid cells, which can be pro-inflammatory4 . Ageing is associated with increased proportions of my-HSCs, resulting in decreased lymphopoiesis and increased myelopoiesis3,5,6 . Transfer of bal-HSCs results in abundant lymphoid and myeloid cells, a stable phenotype that is retained after secondary transfer; my-HSCs also retain their patterns of production after secondary transfer5 . The origin and potential interconversion of these two subsets is still unclear. If they are separate subsets postnatally, it might be possible to reverse the ageing phenotype by eliminating my-HSCs in aged mice. Here we demonstrate that antibody-mediated depletion of my-HSCs in aged mice restores characteristic features of a more youthful immune system, including increasing common lymphocyte progenitors, naive T cells and B cells, while decreasing age-related markers of immune decline. Depletion of my-HSCs in aged mice improves primary and secondary adaptive immune responses to viral infection. These findings may have relevance to the understanding and intervention of diseases exacerbated or caused by dominance of the haematopoietic system by my-HSCs., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2024
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11. Practical Mouse Model to Investigate Therapeutics for Staphylococcusaureus Contaminated Surgical Mesh Implants.
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Collins MM, Race B, Messer RJ, Baune C, Kobayashi SD, Long D, Williams K, Hasenkrug AM, Hasenkrug K, and Malachowa N
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- Humans, Animals, Mice, Surgical Mesh, Anti-Bacterial Agents therapeutic use, Disease Models, Animal, Herniorrhaphy methods, Surgical Wound Infection prevention & control, Methicillin-Resistant Staphylococcus aureus, Staphylococcal Infections microbiology, Daptomycin, Hernia, Ventral surgery
- Abstract
Introduction: The use of prosthetic mesh in hernia repair provides a powerful tool to increase repair longevity, decrease recurrence rates, and facilitate complex abdominal wall reconstruction. Overall infection rates with mesh are low, but for those affected there is high morbidity and economic cost. The availability of a practicable small animal model would be advantageous for the preclinical testing of prophylactics, therapeutics, and new biomaterials. To this end, we have developed a novel mouse model for implantation of methicillin-resistant Staphylococcus aureus-infected surgical mesh and provide results from antibiotic and immunotherapeutic testing., Materials and Methods: Implantation of surgical mesh between fascial planes of the mouse hind limb was used to approximate hernia repair in humans. Surgical mesh was inoculated with methicillin-resistant Staphylococcus aureus to test the efficacy of antibiotic therapy with daptomycin and/or immunotherapy to induce macrophage phagocytosis using antibody blockade of the CD47 "don't eat me" molecule. Clinical outcomes were assessed by daily ambulation scores of the animals and by enumeration of mesh-associated bacteria at predetermined end points., Results: A single prophylactic treatment with daptomycin at the time of surgery led to improved ambulation scores and undetectable levels of bacteria in seven of eight mice by 21 days postinfection. Anti-CD47, an activator of macrophage phagocytosis, was ineffective when administered alone or in combination with daptomycin treatment. Ten days of daily antibiotic therapy begun 3 days after infection was ineffective at clearing infection., Conclusions: This fast and simple model allows rapid in vivo testing of novel antimicrobials and immunomodulators to treat surgical implant infections., (Published by Elsevier Inc.)
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- 2023
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12. GORE-TEX SCLERAL-SUTURED ENVISTA INTRAOCULAR LENS DISLOCATION: THREE CASES AND AN ASSESSMENT OF EYELET TENSILE STRENGTH, FRACTURE CHARACTERISTICS, AND RISK FACTORS.
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Lippincott JK, Collins MM, and Tieu BC
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- Humans, Lens Implantation, Intraocular methods, Retrospective Studies, Tensile Strength, Flexural Strength, Vitrectomy methods, Visual Acuity, Sutures adverse effects, Suture Techniques, Risk Factors, Polytetrafluoroethylene, Lenses, Intraocular
- Abstract
Purpose: Three cases of dislocation of a Gore-Tex scleral-sutured EnVista intraocular lens are reported. The tensile strength of the lens eyelets under two suturing methods is assessed. Pursuant surgical considerations are discussed., Methods: A chart review was performed to identify cases of scleral-sutured EnVista lens dislocations. In addition, six EnVista lenses were suspended in a balanced salt solution tank, tied either with suture over haptic or simple pass technique. Eyelet tensile strength was calculated by gradual addition of weights. Eyelet fracture position and width were measured. The tensile strength of one additional EnVista lens was assessed in open air., Patients: In a retrospective, consecutive case series, three dislocated lenses were identified out of 17 surgeries from one institution. Two dislocations occurred postoperatively, and one occurred intraoperatively., Results: The EnVista eyelet demonstrated greater tensile strength tied with the simple pass method (0.27 ± 0.017 N, n = 3) than with the suture over haptic method (0.15 ± 0.016 N, n = 3; P = 0.0015). Eyelet fracture location corresponded to tensile strength. The lens in air withstood greater tensile stress., Conclusion: Stress is placed on different regions of the eyelet with each suturing method. Simple pass may withstand greater tension and decrease risk for lens fracture, but the operating surgeon must consider multiple factors when forming an operative plan.
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- 2023
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13. Early calcium and cardiac contraction defects in a model of phospholamban R9C mutation in zebrafish.
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Vicente M, Salgado-Almario J, Valiente-Gabioud AA, Collins MM, Vincent P, Domingo B, and Llopis J
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- Animals, Cardiomegaly, Cardiomyopathy, Dilated pathology, Mutation, Calcium metabolism, Calcium-Binding Proteins genetics, Myocardial Contraction, Zebrafish genetics
- Abstract
The phospholamban mutation Arg 9 to Cys (R9C) has been found to cause a dilated cardiomyopathy in humans and in transgenic mice, with ventricular dilation and premature death. Emerging evidence suggests that phospholamban R9C is a loss-of-function mutation with dominant negative effect on SERCA2a activity. We imaged calcium and cardiac contraction simultaneously in 3 and 9 days-post-fertilization (dpf) zebrafish larvae expressing plnb
R9C in the heart to unveil the early pathological pathway that triggers the disease. We generated transgenic zebrafish lines expressing phospholamban wild-type (Tg(myl7:plnbwt )) and phospholamban R9C (Tg(myl7:plnbR9C )) in the heart of zebrafish. To measure calcium and cardiac contraction in 3 and 9 dpf larvae, Tg(myl7:plnbwt ) and Tg(myl7:plnbR9C ) fish were outcrossed with a transgenic line expressing the ratiometric fluorescent calcium biosensor mCyRFP1-GCaMP6f. We found that PlnbR9C raised calcium transient amplitude, induced positive inotropy and lusitropy, and blunted the β-adrenergic response to isoproterenol in 3 dpf larvae. These effects can be attributed to enhanced SERCA2a activity induced by the PlnbR9C mutation. In contrast, Tg(myl7:plnbR9C ) larvae at 9 dpf exhibited ventricular dilation, systolic dysfunction and negative lusitropy, hallmarks of a dilated cardiomyopathy in humans. Importantly, N-acetyl-L-cysteine rescued this deleterious phenotype, suggesting that reactive oxygen species contribute to the pathological pathway. These results also imply that dysregulation of calcium homeostasis during embryo development contributes to the disease progression at later stages. Our in vivo model in zebrafish allows characterization of pathophysiological mechanisms leading to heart disease, and can be used for screening of potential therapeutical agents., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)- Published
- 2022
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14. Attitudes & practices surrounding pregnancy post heart transplant among pediatric providers.
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Collins MM, Ou Z, Millar MM, Kittleson MM, May LJ, Ploutz MS, Molina KM, Hayes KG, and Lal AK
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- Pregnancy, Adult, Child, Humans, Female, United States, Surveys and Questionnaires, Attitude, Heart Transplantation, Lung Transplantation
- Abstract
Background: Many pediatric heart transplant (HT) recipients reach adulthood and may be interested in family planning; there is little data regarding safety of pregnancy post HT and clinicians' opinions differ. Pediatric HT clinicians are instrumental in early counseling. Thus, a better understanding of pediatric HT clinicians' practices regarding family planning and how well aligned these practices are with adult transplant centers is essential., Methods: We conducted a confidential, web-based survey of pediatric HT clinicians in fall 2021. We summarized and compared answers using Fisher's exact test., Results: The survey was sent to 53 United States-based HT directors and to the International Society for Heart and Lung Transplantation and Pediatric Heart Transplant Society list serves. There were 69 respondents. The majority (77%) of respondents felt pregnancy was feasible in selected or all female HT recipients. Ten respondents reported that their institution had an established policy regarding pregnancy post HT. A majority (77%) of HT clinicians would either use a shared care model or recommend transition to their adult institution if pregnancy occurred, though 74% of respondents were either unaware of their corresponding adult institution's policy (62%) or had a counterpart adult program with a policy against pregnancy post HT (12%)., Conclusions: While many clinicians feel pregnancy is feasible in pediatric HT recipients, there remains significant practice variation. Few pediatric programs have a policy regarding pregnancy post HT. Future efforts to provide consistent messaging between adult and pediatric HT programs regarding the feasibility and care of post HT pregnancy are warranted., Competing Interests: Disclosure statement The authors have no actual or potential conflicts of interest (financial, competitive, or otherwise) to disclose. This investigation was supported by the University of Utah Study Design and Biostatistics Center with funding in part from the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through Grant 8UL1TR000105 (formerly UL1RR025764) and Award Number UL1TR002538. This content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health., (Copyright © 2022 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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15. A Smartphone App to Increase Immunizations in the Pediatric Solid Organ Transplant Population: Development and Initial Usability Study.
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Feldman AG, Moore S, Bull S, Morris MA, Wilson K, Bell C, Collins MM, Denize KM, and Kempe A
- Abstract
Background: Vaccine-preventable infections result in significant morbidity, mortality, and costs in pediatric transplant recipients. However, at the time of transplant, less than 20% of children are up-to-date for age-appropriate immunizations that could prevent these diseases. Smartphone apps have the potential to increase immunization rates through their ability to provide vaccine education, send vaccine reminders, and facilitate communication between parents and a multidisciplinary medical group., Objective: The aim of this study was to describe the development of a smartphone app, Immunize PediatricTransplant, to promote pretransplant immunization and to report on app functionality and usability when applied to the target population., Methods: We used a mixed methods study design guided by the Mobile Health Agile Development and Evaluation Lifecycle. We first completed a formative research including semistructured interviews with transplant stakeholders (12 primary care physicians, 40 parents or guardians of transplant recipients, 11 transplant nurse coordinators, and 19 transplant subspecialists) to explore the acceptability of an immunization app to be used in the pretransplant period. Based on these findings, CANImmunize Inc developed the Immunize PediatricTransplant app. We next held 2 focus group discussions with 5-6 transplant stakeholders/group (n=11; 5 parents of transplant recipients, 2 primary care physicians, 2 transplant nurse coordinators, and 2 transplant subspecialists) to receive feedback on the app. After the app modifications were made, alpha testing was conducted on the functional prototype. We then implemented beta testing with 12 stakeholders (6 parents of transplant recipients, 2 primary care doctors, 2 transplant nurse coordinators, and 2 transplant subspecialists) to refine the app through an iterative process. Finally, the stakeholders completed the user version of the Mobile Application Rating Scale (uMARS) to assess the functionality and quality of the app., Results: A new Android- and Apple-compatible app, Immunize PediatricTransplant, was developed to improve immunization delivery in the pretransplant period. The app contains information about vaccine use in the pretransplant period, houses a complete immunization record for each child, includes a communication tool for parents and care providers, and sends automated reminders to parents and care providers when immunizations are due. During usability testing, the stakeholders were able to enter a mock vaccine record containing 16 vaccines in an average of 8.1 minutes (SD 1.8) with 87% accuracy. The stakeholders rated engagement, functionality, aesthetics, and information quality of the app as 4.2/5, 4.5/5, 4.6/5, and 4.8/5, respectively. All participants reported that they would recommend this app to families and care teams with a child awaiting solid organ transplant., Conclusions: Through a systematic, user-centered, agile, iterative approach, the Immunize PediatricTransplant app was developed to improve immunization delivery in the pretransplant period. The app tested well with end users. Further testing and agile development among patients awaiting transplant are needed to understand real-world acceptability and effectiveness in improving immunization rates in children awaiting transplant., (©Amy G Feldman, Susan Moore, Sheana Bull, Megan A Morris, Kumanan Wilson, Cameron Bell, Margaret M Collins, Kathryn M Denize, Allison Kempe. Originally published in JMIR Formative Research (https://formative.jmir.org), 13.01.2022.)
- Published
- 2022
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16. Modeling Human Cardiac Arrhythmias: Insights from Zebrafish.
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Gauvrit S, Bossaer J, Lee J, and Collins MM
- Abstract
Cardiac arrhythmia, or irregular heart rhythm, is associated with morbidity and mortality and is described as one of the most important future public health challenges. Therefore, developing new models of cardiac arrhythmia is critical for understanding disease mechanisms, determining genetic underpinnings, and developing new therapeutic strategies. In the last few decades, the zebrafish has emerged as an attractive model to reproduce in vivo human cardiac pathologies, including arrhythmias. Here, we highlight the contribution of zebrafish to the field and discuss the available cardiac arrhythmia models. Further, we outline techniques to assess potential heart rhythm defects in larval and adult zebrafish. As genetic tools in zebrafish continue to bloom, this model will be crucial for functional genomics studies and to develop personalized anti-arrhythmic therapies.
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- 2022
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17. Correlation of features on OCT with visual acuity and Gass lesion type in Best vitelliform macular dystrophy.
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Coussa RG, Fortenbach CR, Critser DB, Collins MM, Tucker BA, Mullins RF, Sohn EH, Stone EM, and Han IC
- Abstract
Objective: To correlate structural features seen on optical coherence tomography (OCT) with best-corrected visual acuity (BCVA) and Gass lesion type in patients with Best vitelliform macular dystrophy (BVMD)., Methods and Analysis: This is a retrospective case series of consecutive patients with molecularly confirmed BEST1- associated BVMD. OCT scans were reviewed for lesion status and presence of subretinal pillar, focal choroidal excavation (FCE), intraretinal fluid or atrophy. Available OCT angiography images were used to evaluate for the presence of choroidal neovascularisation (CNV). These features were then correlated with BCVA and Gass lesion type., Results: 95 eyes from 48 patients (mean age 38.9 years, range 4-87) were included. The presence of a pillar (24.2%), FCE (20.0%) and atrophy (7.4%) were associated with poor BCVA (p<0.05). Gass lesion type 1 eyes were correlated with good BCVA (LogMAR <0.4) whereas type 5 eyes had poor BCVA (LogMAR >0.4). Among 65 eyes with longitudinal data (mean follow-up 5.1 years), 7 eyes (10.8%) reverted from higher to lower Gass lesion type; of these, 4 eyes (57.1%) had CNV responsive to intravitreal anti-vascular endothelial growth factor treatment., Conclusion: OCT-based structural features are readily identifiable in patients with BVMD and have prognostic importance due to their correlation with BCVA., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
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18. Cardioluminescence in Transgenic Zebrafish Larvae: A Calcium Imaging Tool to Study Drug Effects and Pathological Modeling.
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Vicente M, Salgado-Almario J, Collins MM, Martínez-Sielva A, Minoshima M, Kikuchi K, Domingo B, and Llopis J
- Abstract
Zebrafish embryos and larvae have emerged as an excellent model in cardiovascular research and are amenable to live imaging with genetically encoded biosensors to study cardiac cell behaviours, including calcium dynamics. To monitor calcium ion levels in three to five days post-fertilization larvae, we have used bioluminescence. We generated a transgenic line expressing GFP-aequorin in the heart, Tg(myl7:GA) , and optimized a reconstitution protocol to boost aequorin luminescence. The analogue diacetyl h -coelenterazine enhanced light output and signal-to-noise ratio. With this cardioluminescence model, we imaged the time-averaged calcium levels and beat-to-beat calcium oscillations continuously for hours. As a proof-of-concept of the transgenic line, changes in ventricular calcium levels were observed by Bay K8644, an L-type calcium channel activator and with the blocker nifedipine. The β-adrenergic blocker propranolol decreased calcium levels, heart rate, stroke volume, and cardiac output, suggesting that larvae have a basal adrenergic tone. Zebrafish larvae treated with terfenadine for 24 h have been proposed as a model of heart failure. Tg(myl7:GA) larvae treated with terfenadine showed bradycardia, 2:1 atrioventricular block, decreased time-averaged ventricular calcium levels but increased calcium transient amplitude, and reduced cardiac output. As alterations of calcium signalling are involved in the pathogenesis of heart failure and arrhythmia, the GFP-aequorin transgenic line provides a powerful platform for understanding calcium dynamics.
- Published
- 2021
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19. Recovery from Acute SARS-CoV-2 Infection and Development of Anamnestic Immune Responses in T Cell-Depleted Rhesus Macaques.
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Hasenkrug KJ, Feldmann F, Myers L, Santiago ML, Guo K, Barrett BS, Mickens KL, Carmody A, Okumura A, Rao D, Collins MM, Messer RJ, Lovaglio J, Shaia C, Rosenke R, van Doremalen N, Clancy C, Saturday G, Hanley P, Smith BJ, Meade-White K, Shupert WL, Hawman DW, and Feldmann H
- Subjects
- Animals, CD4-Positive T-Lymphocytes cytology, CD4-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes immunology, COVID-19 immunology, Female, Lymphocyte Depletion methods, Macaca mulatta immunology, Male, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, COVID-19 pathology, Immunologic Memory immunology, Lymphopenia immunology, SARS-CoV-2 immunology
- Abstract
Severe coronavirus disease 2019 (COVID-19) has been associated with T cell lymphopenia, but no causal effect of T cell deficiency on disease severity has been established. To investigate the specific role of T cells in recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, we studied rhesus macaques that were depleted of either CD4
+ , CD8+ , or both T cell subsets prior to infection. Peak virus loads were similar in all groups, but the resolution of virus in the T cell-depleted animals was slightly delayed compared to that in controls. The T cell-depleted groups developed virus-neutralizing antibody responses and class switched to IgG. When reinfected 6 weeks later, the T cell-depleted animals showed anamnestic immune responses characterized by rapid induction of high-titer virus-neutralizing antibodies, faster control of virus loads, and reduced clinical signs. These results indicate that while T cells play a role in the recovery of rhesus macaques from acute SARS-CoV-2 infections, their depletion does not induce severe disease, and T cells do not account for the natural resistance of rhesus macaques to severe COVID-19. Neither primed CD4+ nor CD8+ T cells appeared critical for immunoglobulin class switching, the development of immunological memory, or protection from a second infection. IMPORTANCE Patients with severe COVID-19 often have decreased numbers of T cells, a cell type important in fighting most viral infections. However, it is not known whether the loss of T cells contributes to severe COVID-19 or is a consequence of it. We studied rhesus macaques, which develop only mild COVID-19, similar to most humans. Experimental depletion of T cells slightly prolonged their clearance of virus, but there was no increase in disease severity. Furthermore, they were able to develop protection from a second infection and produced antibodies capable of neutralizing the virus. They also developed immunological memory, which allows a much stronger and more rapid response upon a second infection. These results suggest that T cells are not critical for recovery from acute SARS-CoV-2 infections in this model and point toward B cell responses and antibodies as the essential mediators of protection from re-exposure.- Published
- 2021
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20. The Accessory Gene saeP of the SaeR/S Two-Component Gene Regulatory System Impacts Staphylococcus aureus Virulence During Neutrophil Interaction.
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Collins MM, Behera RK, Pallister KB, Evans TJ, Burroughs O, Flack C, Guerra FE, Pullman W, Cone B, Dankoff JG, Nygaard TK, Brinsmade SR, and Voyich JM
- Abstract
Staphylococcus aureus ( S. aureus ) causes a range of diseases ranging from superficial skin and soft-tissue infections to invasive and life-threatening conditions (Klevens et al., 2007; Kobayashi et al., 2015). S. aureus utilizes the Sae sensory system to adapt to neutrophil challenge. Although the roles of the SaeR response regulator and its cognate sensor kinase SaeS have been demonstrated to be critical for surviving neutrophil interaction and for causing infection, the roles for the accessory proteins SaeP and SaeQ remain incompletely defined. To characterize the functional role of these proteins during innate immune interaction, we generated isogenic deletion mutants lacking these accessory genes in USA300 (USA300Δ saeP and USA300Δ saeQ ). S. aureus survival was increased following phagocytosis of USA300Δ saeP compared to USA300 by neutrophils. Additionally, secreted extracellular proteins produced by USA300Δ saeP cells caused significantly more plasma membrane damage to human neutrophils than extracellular proteins produced by USA300 cells. Deletion of saeQ resulted in a similar phenotype, but effects did not reach significance during neutrophil interaction. The enhanced cytotoxicity of USA300Δ saeP cells toward human neutrophils correlated with an increased expression of bi-component leukocidins known to target these immune cells. A saeP and saeQ double mutant (USA300Δ saePQ ) showed a significant increase in survival following neutrophil phagocytosis that was comparable to the USA300Δ saeP single mutant and increased the virulence of USA300 during murine bacteremia. These data provide evidence that SaeP modulates the Sae-mediated response of S. aureus against human neutrophils and suggest that saeP and saeQ together impact pathogenesis in vivo ., (Copyright © 2020 Collins, Behera, Pallister, Evans, Burroughs, Flack, Guerra, Pullman, Cone, Dankoff, Nygaard, Brinsmade and Voyich.)
- Published
- 2020
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21. Hhex regulates the specification and growth of the hepatopancreatic ductal system.
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Villasenor A, Gauvrit S, Collins MM, Maischein HM, and Stainier DYR
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- Animals, Animals, Genetically Modified metabolism, Body Patterning physiology, Digestive System metabolism, Embryo, Nonmammalian metabolism, Endoderm metabolism, Endothelial Cells metabolism, Gene Expression Regulation, Developmental genetics, Hepatopancreas metabolism, Homeodomain Proteins genetics, Repressor Proteins genetics, Zebrafish genetics, Zebrafish metabolism, Zebrafish Proteins genetics, Hepatopancreas embryology, Hepatopancreas growth & development, Repressor Proteins metabolism, Zebrafish Proteins metabolism
- Abstract
Significant efforts have advanced our understanding of foregut-derived organ development; however, little is known about the molecular mechanisms that underlie the formation of the hepatopancreatic ductal (HPD) system. Here, we report a role for the homeodomain transcription factor Hhex in directing HPD progenitor specification in zebrafish. Loss of Hhex function results in impaired HPD system formation. We found that Hhex specifies a distinct population of HPD progenitors that gives rise to the cystic duct, common bile duct, and extra-pancreatic duct. Since hhex is not uniquely expressed in the HPD region but is also expressed in endothelial cells and the yolk syncytial layer (YSL), we tested the role of blood vessels as well as the YSL in HPD formation. We found that blood vessels are required for HPD patterning, but not for HPD progenitor specification. In addition, we found that Hhex is required in both the endoderm and the YSL for HPD development. Our results shed light on the mechanisms directing endodermal progenitors towards the HPD fate and emphasize the tissue specific requirement of Hhex during development., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2020
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22. Early sarcomere and metabolic defects in a zebrafish pitx2c cardiac arrhythmia model.
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Collins MM, Ahlberg G, Hansen CV, Guenther S, Marín-Juez R, Sokol AM, El-Sammak H, Piesker J, Hellsten Y, Olesen MS, Stainier DYR, and Lundegaard PR
- Subjects
- Acetylcysteine pharmacology, Animals, Animals, Genetically Modified, Antioxidants pharmacology, Arrhythmias, Cardiac drug therapy, Arrhythmias, Cardiac etiology, Cardiac Conduction System Disease etiology, Cardiac Conduction System Disease genetics, Cardiomyopathies genetics, Cardiomyopathies physiopathology, Disease Models, Animal, Electrocardiography, Gene Expression Regulation, Homeodomain Proteins metabolism, Larva drug effects, Mitochondria, Heart genetics, Mitochondria, Heart metabolism, Mitochondria, Heart pathology, Sarcomeres genetics, Sarcomeres pathology, Stress, Physiological genetics, Transcription Factors metabolism, Zebrafish Proteins metabolism, Arrhythmias, Cardiac metabolism, Homeodomain Proteins genetics, Sarcomeres metabolism, Transcription Factors genetics, Zebrafish genetics, Zebrafish Proteins genetics
- Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. The major AF susceptibility locus 4q25 establishes long-range interactions with the promoter of PITX2 , a transcription factor gene with critical functions during cardiac development. While many AF-linked loci have been identified in genome-wide association studies, mechanistic understanding into how genetic variants, including those at the 4q25 locus, increase vulnerability to AF is mostly lacking. Here, we show that loss of pitx2c in zebrafish leads to adult cardiac phenotypes with substantial similarities to pathologies observed in AF patients, including arrhythmia, atrial conduction defects, sarcomere disassembly, and altered cardiac metabolism. These phenotypes are also observed in a subset of pitx2c
+/- fish, mimicking the situation in humans. Most notably, the onset of these phenotypes occurs at an early developmental stage. Detailed analyses of pitx2c loss- and gain-of-function embryonic hearts reveal changes in sarcomeric and metabolic gene expression and function that precede the onset of cardiac arrhythmia first observed at larval stages. We further find that antioxidant treatment of pitx2c-/- larvae significantly reduces the incidence and severity of cardiac arrhythmia, suggesting that metabolic dysfunction is an important driver of conduction defects. We propose that these early sarcomere and metabolic defects alter cardiac function and contribute to the electrical instability and structural remodeling observed in adult fish. Overall, these data provide insight into the mechanisms underlying the development and pathophysiology of some cardiac arrhythmias and importantly, increase our understanding of how developmental perturbations can predispose to functional defects in the adult heart., Competing Interests: The authors declare no competing interest.- Published
- 2019
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23. Development of a Molecularly Stable Gene Therapy Vector for the Treatment of RPGR -Associated X-Linked Retinitis Pigmentosa.
- Author
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Giacalone JC, Andorf JL, Zhang Q, Burnight ER, Ochoa D, Reutzel AJ, Collins MM, Sheffield VC, Mullins RF, Han IC, Stone EM, and Tucker BA
- Subjects
- Alleles, Amino Acid Substitution, Base Sequence, Dependovirus genetics, Exons, Gene Expression, Gene Order, Genetic Variation, Genetic Vectors administration & dosage, Humans, Male, Open Reading Frames, Plasmids genetics, Retinitis Pigmentosa metabolism, Retinitis Pigmentosa therapy, Sequence Analysis, DNA, Transgenes, Eye Proteins genetics, Genes, X-Linked, Genetic Therapy methods, Genetic Vectors genetics, Mutation, Retinitis Pigmentosa genetics
- Abstract
In a screen of 1,000 consecutively ascertained families, we recently found that mutations in the gene RPGR are the third most common cause of all inherited retinal disease. As the two most frequent disease-causing genes, ABCA4 and USH2A , are far too large to fit into clinically relevant adeno-associated virus (AAV) vectors, RPGR is an obvious early target for AAV-based ocular gene therapy. In generating plasmids for this application, we discovered that those containing wild-type RPGR sequence, which includes the highly repetitive low complexity region ORF15, were extremely unstable ( i.e. , they showed consistent accumulation of genomic changes during plasmid propagation). To develop a stable RPGR gene transfer vector, we used a bioinformatics approach to identify predicted regions of genomic instability within ORF15 ( i.e. , potential non-B DNA conformations). Synonymous substitutions were made in these regions to reduce the repetitiveness and increase the molecular stability while leaving the encoded amino acid sequence unchanged. The resulting construct was subsequently packaged into AAV serotype 5, and the ability to drive transcript expression and functional protein production was demonstrated via subretinal injection in rat and pull-down assays, respectively. By making synonymous substitutions within the repetitive region of RPGR , we were able to stabilize the plasmid and subsequently generate a clinical-grade gene transfer vector (IA-RPGR). Following subretinal injection in rat, we demonstrated that the augmented transcript was expressed at levels similar to wild-type constructs. By performing in vitro pull-down experiments, we were able to show that IA-RPGR protein product retained normal protein binding properties ( i.e. , analysis revealed normal binding to PDE6D, INPP5E, and RPGRIP1L). In summary, we have generated a stable RPGR gene transfer vector capable of producing functional RPGR protein, which will facilitate safety and toxicity studies required for progression to an Investigational New Drug application.
- Published
- 2019
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24. Correction: Loss of the Mia40a oxidoreductase leads to hepato-pancreatic insufficiency in zebrafish.
- Author
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Sokol AM, Uszczynska-Ratajczak B, Collins MM, Bazala M, Topf U, Lundegaard PR, Sugunan S, Guenther S, Kuenne C, Graumann J, Chan SSL, Stainier DYR, and Chacinska A
- Abstract
[This corrects the article DOI: 10.1371/journal.pgen.1007743.].
- Published
- 2019
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25. Aspartic Acid Residue 51 of SaeR Is Essential for Staphylococcus aureus Virulence.
- Author
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Nygaard TK, Borgogna TR, Sward EW, Guerra FE, Dankoff JG, Collins MM, Pallister KB, Chen L, Kreiswirth BN, and Voyich JM
- Abstract
Staphylococcus aureus is a common Gram-positive bacteria that is a major cause of human morbidity and mortality. The SaeR/S two-component sensory system of S. aureus is important for virulence gene transcription and pathogenesis. However, the influence of SaeR phosphorylation on virulence gene transcription is not clear. To determine the importance of potential SaeR phosphorylation sites for S. aureus virulence, we generated genomic alanine substitutions at conserved aspartic acid residues in the receiver domain of the SaeR response regulator in clinically significant S. aureus pulsed-field gel electrophoresis (PFGE) type USA300. Transcriptional analysis demonstrated a dramatic reduction in the transcript abundance of various toxins, adhesins, and immunomodulatory proteins for SaeR with an aspartic acid to alanine substitution at residue 51. These findings corresponded to a significant decrease in cytotoxicity against human erythrocytes and polymorphonuclear leukocytes, the ability to block human myeloperoxidase activity, and pathogenesis during murine soft-tissue infection. Analysis of SaeR sequences from over 8,000 draft S. aureus genomes revealed that aspartic acid residue 51 is 100% conserved. Collectively, these results demonstrate that aspartic acid residue 51 of SaeR is essential for S. aureus virulence and underscore a conserved target for novel antimicrobial strategies that treat infection caused by this pathogen.
- Published
- 2018
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26. Loss of the Mia40a oxidoreductase leads to hepato-pancreatic insufficiency in zebrafish.
- Author
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Sokol AM, Uszczynska-Ratajczak B, Collins MM, Bazala M, Topf U, Lundegaard PR, Sugunan S, Guenther S, Kuenne C, Graumann J, Chan SSL, Stainier DYR, and Chacinska A
- Abstract
Development and function of tissues and organs are powered by the activity of mitochondria. In humans, inherited genetic mutations that lead to progressive mitochondrial pathology often manifest during infancy and can lead to death, reflecting the indispensable nature of mitochondrial biogenesis and function. Here, we describe a zebrafish mutant for the gene mia40a (chchd4a), the life-essential homologue of the evolutionarily conserved Mia40 oxidoreductase which drives the biogenesis of cysteine-rich mitochondrial proteins. We report that mia40a mutant animals undergo progressive cellular respiration defects and develop enlarged mitochondria in skeletal muscles before their ultimate death at the larval stage. We generated a deep transcriptomic and proteomic resource that allowed us to identify abnormalities in the development and physiology of endodermal organs, in particular the liver and pancreas. We identify the acinar cells of the exocrine pancreas to be severely affected by mutations in the MIA pathway. Our data contribute to a better understanding of the molecular, cellular and organismal effects of mitochondrial deficiency, important for the accurate diagnosis and future treatment strategies of mitochondrial diseases., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2018
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27. Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol.
- Author
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Huang Z, Vlisides PE, Tarnal VC, Janke EL, Keefe KM, Collins MM, McKinney AM, Picton P, Harris RE, Mashour GA, and Hudetz AG
- Subjects
- Adult, Anesthetics, Intravenous pharmacology, Brain diagnostic imaging, Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Male, Neuroimaging, Young Adult, Brain drug effects, Brain physiology, Consciousness drug effects, Hypnotics and Sedatives pharmacology, Propofol pharmacology
- Abstract
Detecting covert consciousness in behaviorally unresponsive patients by brain imaging is of great interest, but a reproducible model and evidence from independent sources is still lacking. Here we demonstrate the possibility of using general anesthetics in a within-subjects study design to test methods or statistical paradigms of assessing covert consciousness. Using noninvasive neuroimaging in healthy volunteers, we identified a healthy study participant who was able to exhibit the specific fMRI signatures of volitional mental imagery while behaviorally unresponsive due to sedation with propofol. Our findings reveal a novel model that may accelerate the development of new approaches to reproducibly detect covert consciousness, which is difficult to achieve in patients with heterogeneous and sometimes clinically unstable neuropathology.
- Published
- 2018
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28. HHEX is a transcriptional regulator of the VEGFC/FLT4/PROX1 signaling axis during vascular development.
- Author
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Gauvrit S, Villasenor A, Strilic B, Kitchen P, Collins MM, Marín-Juez R, Guenther S, Maischein HM, Fukuda N, Canham MA, Brickman JM, Bogue CW, Jayaraman PS, and Stainier DYR
- Subjects
- Animals, Animals, Genetically Modified, Base Sequence, Blood Vessels cytology, Blood Vessels growth & development, Blood Vessels metabolism, Cell Line, Embryo, Mammalian, Embryo, Nonmammalian, Endothelial Cells cytology, Endothelial Cells metabolism, Homeodomain Proteins metabolism, Humans, Lymphatic Vessels cytology, Lymphatic Vessels metabolism, Mice, Neovascularization, Physiologic genetics, Repressor Proteins deficiency, Signal Transduction, Transcription, Genetic, Tumor Suppressor Proteins metabolism, Vascular Endothelial Growth Factor C metabolism, Vascular Endothelial Growth Factor Receptor-3 metabolism, Zebrafish, Zebrafish Proteins deficiency, Zebrafish Proteins metabolism, Gene Expression Regulation, Developmental, Homeodomain Proteins genetics, Lymphangiogenesis genetics, Repressor Proteins genetics, Tumor Suppressor Proteins genetics, Vascular Endothelial Growth Factor C genetics, Vascular Endothelial Growth Factor Receptor-3 genetics, Zebrafish Proteins genetics
- Abstract
Formation of the lymphatic system requires the coordinated expression of several key regulators: vascular endothelial growth factor C (VEGFC), its receptor FLT4, and a key transcriptional effector, PROX1. Yet, how expression of these signaling components is regulated remains poorly understood. Here, using a combination of genetic and molecular approaches, we identify the transcription factor hematopoietically expressed homeobox (HHEX) as an upstream regulator of VEGFC, FLT4, and PROX1 during angiogenic sprouting and lymphatic formation in vertebrates. By analyzing zebrafish mutants, we found that hhex is necessary for sprouting angiogenesis from the posterior cardinal vein, a process required for lymphangiogenesis. Furthermore, studies of mammalian HHEX using tissue-specific genetic deletions in mouse and knockdowns in cultured human endothelial cells reveal its highly conserved function during vascular and lymphatic development. Our findings that HHEX is essential for the regulation of the VEGFC/FLT4/PROX1 axis provide insights into the molecular regulation of lymphangiogenesis.
- Published
- 2018
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29. Pitx2c orchestrates embryonic axis extension via mesendodermal cell migration.
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Collins MM, Maischein HM, Dufourcq P, Charpentier M, Blader P, and Stainier DY
- Subjects
- Animals, Animals, Genetically Modified, Body Patterning genetics, Cell Shape, Chemokines genetics, Chemokines metabolism, Embryo, Nonmammalian, Endoderm cytology, Endoderm metabolism, Epithelial Cells cytology, Extracellular Matrix Proteins genetics, Extracellular Matrix Proteins metabolism, Gastrulation genetics, Integrins genetics, Integrins metabolism, Mutation, Notochord cytology, Notochord metabolism, Time-Lapse Imaging, Transcription Factors metabolism, Transcriptome, Zebrafish growth & development, Zebrafish metabolism, Zebrafish Proteins metabolism, Zygote cytology, Zygote growth & development, Zygote metabolism, Cell Movement genetics, Embryonic Development genetics, Epithelial Cells metabolism, Gene Expression Regulation, Developmental, Transcription Factors genetics, Zebrafish genetics, Zebrafish Proteins genetics
- Abstract
Pitx2c, a homeodomain transcription factor, is classically known for its left-right patterning role. However, an early wave of pitx2 expression occurs at the onset of gastrulation in several species, indicating a possible earlier role that remains relatively unexplored. Here we show that in zebrafish, maternal-zygotic (MZ) pitx2c mutants exhibit a shortened body axis indicative of convergence and extension (CE) defects. Live imaging reveals that MZ pitx2c mutants display less persistent mesendodermal migration during late stages of gastrulation. Transplant data indicate that Pitx2c functions cell non-autonomously to regulate this cell behavior by modulating cell shape and protrusive activity. Using transcriptomic analyses and candidate gene approaches, we identify transcriptional changes in components of the chemokine-ECM-integrin dependent mesendodermal migration network. Together, our results define pathways downstream of Pitx2c that are required during early embryogenesis and reveal novel functions for Pitx2c as a regulator of morphogenesis., Competing Interests: MC, HM, PD, MC, PB No competing interests declared, DS Senior editor, eLife, (© 2018, Collins et al.)
- Published
- 2018
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30. The Hippo pathway effector Wwtr1 regulates cardiac wall maturation in zebrafish.
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Lai JKH, Collins MM, Uribe V, Jiménez-Amilburu V, Günther S, Maischein HM, and Stainier DYR
- Subjects
- Animals, Animals, Genetically Modified, Cell Proliferation physiology, Intercellular Junctions physiology, Intracellular Signaling Peptides and Proteins genetics, Morpholinos genetics, Myosin Heavy Chains genetics, Neuregulins metabolism, Organogenesis genetics, Protein Serine-Threonine Kinases metabolism, Receptor, ErbB-2 metabolism, Serine-Threonine Kinase 3, Signal Transduction physiology, Trans-Activators metabolism, Transcriptional Coactivator with PDZ-Binding Motif Proteins, Troponin T genetics, YAP-Signaling Proteins, Zebrafish, Zebrafish Proteins genetics, Heart embryology, Heart growth & development, Intracellular Signaling Peptides and Proteins metabolism, Myocytes, Cardiac cytology, Organogenesis physiology, Zebrafish Proteins metabolism
- Abstract
Cardiac trabeculation is a highly regulated process that starts with the delamination of compact layer cardiomyocytes. The Hippo signaling pathway has been implicated in cardiac development but many questions remain. We have investigated the role of Wwtr1, a nuclear effector of the Hippo pathway, in zebrafish and find that its loss leads to reduced cardiac trabeculation. However, in mosaic animals, wwtr1
-/- cardiomyocytes contribute more frequently than wwtr1+/- cardiomyocytes to the trabecular layer of wild-type hearts. To investigate this paradox, we examined the myocardial wall at early stages and found that compact layer cardiomyocytes in wwtr1-/- hearts exhibit disorganized cortical actin structure and abnormal cell-cell junctions. Accordingly, wild-type cardiomyocytes in mosaic mutant hearts contribute less frequently to the trabecular layer than when present in mosaic wild-type hearts, indicating that wwtr1-/- hearts are not able to support trabeculation. We also found that Nrg/Erbb2 signaling, which is required for trabeculation, could promote Wwtr1 nuclear export in cardiomyocytes. Altogether, these data suggest that Wwtr1 establishes the compact wall architecture necessary for trabeculation, and that Nrg/Erbb2 signaling negatively regulates its nuclear localization and therefore its activity., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)- Published
- 2018
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31. Generation of Xeno-Free, cGMP-Compliant Patient-Specific iPSCs from Skin Biopsy.
- Author
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Wiley LA, Anfinson KR, Cranston CM, Kaalberg EE, Collins MM, Mullins RF, Stone EM, and Tucker BA
- Subjects
- Biopsy, Humans, Cell Culture Techniques methods, Cellular Reprogramming Techniques methods, Dermis metabolism, Dermis pathology, Fibroblasts metabolism, Fibroblasts pathology, Induced Pluripotent Stem Cells metabolism, Induced Pluripotent Stem Cells pathology, Retina metabolism, Retina pathology
- Abstract
This unit describes protocols for the generation of clinical-grade patient-specific induced pluripotent stem cell (iPSC)-derived retinal cells from patients with inherited retinal degenerative blindness. Specifically, we describe how, using xeno-free reagents in an ISO class 5 environment, one can isolate and culture dermal fibroblasts, generate iPSCs, and derive autologous retinal cells via 3-D differentiation. The universal methods described herein for the isolation of dermal fibroblasts and generation of iPSCs can be employed regardless of disease, tissue, or cell type of interest. © 2017 by John Wiley & Sons, Inc., (Copyright © 2017 John Wiley & Sons, Inc.)
- Published
- 2017
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32. Claudins are essential for cell shape changes and convergent extension movements during neural tube closure.
- Author
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Baumholtz AI, Simard A, Nikolopoulou E, Oosenbrug M, Collins MM, Piontek A, Krause G, Piontek J, Greene NDE, and Ryan AK
- Subjects
- Actin Cytoskeleton metabolism, Adaptor Proteins, Signal Transducing, Animals, Cell Adhesion Molecules metabolism, Cell Cycle Proteins, Chick Embryo, Claudin-3 genetics, Claudin-3 metabolism, Claudin-4 genetics, Claudin-4 metabolism, Claudins genetics, Claudins metabolism, Embryo Culture Techniques, Mice, Morphogenesis physiology, Nerve Tissue Proteins metabolism, Neural Tube Defects genetics, Signal Transduction physiology, cdc42 GTP-Binding Protein metabolism, rho GTP-Binding Proteins metabolism, rhoA GTP-Binding Protein, Cell Polarity physiology, Cell Shape physiology, Neural Plate embryology, Neural Tube embryology, Neurulation physiology, Tight Junctions physiology
- Abstract
During neural tube closure, regulated changes at the level of individual cells are translated into large-scale morphogenetic movements to facilitate conversion of the flat neural plate into a closed tube. Throughout this process, the integrity of the neural epithelium is maintained via cell interactions through intercellular junctions, including apical tight junctions. Members of the claudin family of tight junction proteins regulate paracellular permeability, apical-basal cell polarity and link the tight junction to the actin cytoskeleton. Here, we show that claudins are essential for neural tube closure: the simultaneous removal of Cldn3, -4 and -8 from tight junctions caused folate-resistant open neural tube defects. Their removal did not affect cell type differentiation, neural ectoderm patterning nor overall apical-basal polarity. However, apical accumulation of Vangl2, RhoA, and pMLC were reduced, and Par3 and Cdc42 were mislocalized at the apical cell surface. Our data showed that claudins act upstream of planar cell polarity and RhoA/ROCK signaling to regulate cell intercalation and actin-myosin contraction, which are required for convergent extension and apical constriction during neural tube closure, respectively., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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33. Two-photon polymerization for production of human iPSC-derived retinal cell grafts.
- Author
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Worthington KS, Wiley LA, Kaalberg EE, Collins MM, Mullins RF, Stone EM, and Tucker BA
- Subjects
- Humans, Porosity, Retinal Degeneration metabolism, Retinal Degeneration pathology, Induced Pluripotent Stem Cells metabolism, Membranes, Artificial, Retina metabolism, Retinal Degeneration therapy, Tissue Scaffolds chemistry
- Abstract
Recent advances in induced pluripotent stem cell (iPSC) technology have paved the way for the production of patient-specific neurons that are ideal for autologous cell replacement for treatment of neurodegenerative diseases. In the case of retinal degeneration and associated photoreceptor cell therapy, polymer scaffolds are critical for cellular survival and integration; however, prior attempts to materialize this concept have been unsuccessful in part due to the materials' inability to guide cell alignment. In this work, we used two-photon polymerization to create 180μm wide non-degradable prototype photoreceptor scaffolds with varying pore sizes, slicing distances, hatching distances and hatching types. Hatching distance and hatching type were significant factors for the error of vertical pore diameter, while slicing distance and hatching type most affected the integrity and geometry of horizontal pores. We optimized printing parameters in terms of structural integrity and printing time in order to create 1mm wide scaffolds for cell loading studies. We fabricated these larger structures directly on a porous membrane with 3µm diameter pores and seeded them with human iPSC-derived retinal progenitor cells. After two days in culture, cells nested in and extended neuronal processes parallel to the vertical pores of the scaffolds, with maximum cell loading occurring in 25μm diameter pores. These results highlight the feasibility of using this technique as part of an autologous stem cell strategy for restoring vision to patients affected with retinal degenerative diseases., Statement of Significance: Cell replacement therapy is an important goal for investigators aiming to restore neural function to those suffering from neurodegenerative disease. Cell delivery scaffolds are frequently necessary for the success of such treatments, but traditional biomaterials often fail to facilitate the neuronal orientation and close packing needed to recapitulate the in vivo environment. Here, we use two-photon polymerization to create prototype cell scaffolds with densely packed vertical pores for photoreceptor cell loading and small, interconnected horizontal pores for nutrient diffusion. This study offers a thorough characterization of how two-photon polymerization parameters affect final structural outcomes and printing time. Our findings demonstrate the feasibility of using two-photon polymerization to create scaffolds that can align neuronal cells in 3D and are large enough to be used for transplantation. In future work, these scaffolds could comprise biodegradable materials with tunable microstructure, elastic modulus and degradation time; a significant step towards a promising treatment option for those suffering from late-stage neurodegeneration, including retinal degenerative blindness., (Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2017
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34. Differential regulation of CD103 (αE integrin) expression in human dendritic cells by retinoic acid and Toll-like receptor ligands.
- Author
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Roe MM, Swain S, Sebrell TA, Sewell MA, Collins MM, Perrino BA, Smith PD, Smythies LE, and Bimczok D
- Subjects
- Antigens, CD genetics, CD4-Positive T-Lymphocytes cytology, CD4-Positive T-Lymphocytes immunology, CD4-Positive T-Lymphocytes microbiology, Cell Differentiation, Coculture Techniques, Dendritic Cells cytology, Dendritic Cells immunology, Dendritic Cells microbiology, Gastric Mucosa cytology, Gastric Mucosa drug effects, Gastric Mucosa immunology, Gastric Mucosa microbiology, Gene Expression Regulation, Helicobacter pylori growth & development, Helicobacter pylori immunology, Humans, Integrin alpha Chains genetics, Integrin beta Chains genetics, Integrins genetics, Integrins immunology, Lipopolysaccharides pharmacology, Monocytes cytology, Monocytes immunology, Monocytes microbiology, Primary Cell Culture, RNA, Messenger genetics, RNA, Messenger immunology, Signal Transduction, Toll-Like Receptor 2 agonists, Toll-Like Receptor 2 genetics, Toll-Like Receptor 2 immunology, Transforming Growth Factor beta antagonists & inhibitors, Transforming Growth Factor beta genetics, Transforming Growth Factor beta immunology, Tretinoin immunology, Tretinoin metabolism, Antigens, CD immunology, CD4-Positive T-Lymphocytes drug effects, Dendritic Cells drug effects, Integrin alpha Chains immunology, Integrin beta Chains immunology, Monocytes drug effects, Tretinoin pharmacology
- Abstract
CD103 (αE integrin) is an important dendritic cell (DC) marker that characterizes functionally distinct DC subsets in mice and humans. However, the mechanism by which CD103 expression is regulated in human DCs and the role of CD103 for DC function are not very well understood. Here, we show that retinoic acid (RA) treatment of human monocyte-derived DCs (MoDCs) increased the ability of the DCs to synthesize RA and induced MoDC expression of CD103 and β7 at the mRNA and protein level. In contrast, RA was unable to induce the expression of CD103 in primary human DCs isolated from the gastric mucosa. Inhibition of TGF-β signaling in MoDCs down-regulated RA-induced CD103 expression, indicating that TGF-β-dependent pathways contribute to the induction of CD103. Conversely, when RA-treated MoDCs were stimulated with live Helicobacter pylori , commensal bacteria, LPS, or a TLR2 agonist, the RA-induced up-regulation of CD103 and β7 integrin expression was completely abrogated. To determine whether CD103 expression impacts DC priming of CD4
+ T cells, we next investigated the ability of CD103+ and CD103─ DCs to induce mucosal homing and T cell proliferation. Surprisingly, RA treatment of DCs enhanced both α4β7 expression and proliferation in cocultured T cells, but no difference was seen between RA-treated CD103+ and CD103─ DCs. In summary, our data demonstrate that RA, bacterial products, and the tissue environment all contribute to the regulation of CD103 on human DCs and that DC induction of mucosal homing in T cells is RA dependent but not CD103 dependent., (© Society for Leukocyte Biology.)- Published
- 2017
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35. Pediatric Specialty Transport Teams Are Not Associated With Decreased 48-Hour Pediatric Intensive Care Unit Mortality: A Propensity Analysis of the VPS, LLC Database.
- Author
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Meyer MT, Mikhailov TA, Kuhn EM, Collins MM, and Scanlon MC
- Subjects
- Adolescent, Child, Child, Preschool, Databases, Factual, Female, Humans, Infant, Infant, Newborn, Male, Patient Acuity, Propensity Score, Workforce, Intensive Care Units, Pediatric statistics & numerical data, Mortality, Patient Care Team, Pediatrics, Transportation of Patients
- Abstract
Objective: The purpose of this study was to determine if pediatric specialty pediatric team (SPT) interfacility-transported children from community emergency departments to a pediatric intensive care unit (PICU) have improved 48-hour mortality., Methods: This is a multicenter, historic cohort analysis of the VPS, LLC PICU clinical database (VPS, LLC, Los Angeles, CA) for all PICU directly admitted pediatric patients ≤ 18 years of age from January 1, 2007, to March 31, 2009. Categoric variables were analyzed by the chi-square and Mann-Whitney tests for non-normally distributed continuous variables. The propensity score was determined by multiple logistic regression analysis. Nearest neighbor matching developed emergency medical services SPT pairs by similar propensity score. Multiple regression analyses of the matched pairs determined the association of SPT with 48-hour PICU mortality. P values < .05 were considered significant., Results: This study included 3,795 PICU discharges from 12 hospitals. SPT-transported children were more severely ill, younger in age, and more likely to have a respiratory diagnosis (P < .0001). Unadjusted 48-hour PICU mortality was statistically significantly higher for SPT transports (2.04% vs. 0.070%, P = .0028). Multiple regressions adjusted for propensity score, illness severity, and PICU site showed no significant difference in 48-hour PICU mortality., Conclusion: No significant difference in adjusted 48-hour PICU mortality for children transported by transport team type was discovered., (Copyright © 2016 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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36. Organ Function as a Modulator of Organ Formation: Lessons from Zebrafish.
- Author
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Collins MM and Stainier DY
- Subjects
- Animals, Heart embryology, Heart growth & development, Morphogenesis physiology, Myocytes, Cardiac cytology, Zebrafish embryology
- Abstract
Organogenesis requires an intricate balance between cell differentiation and tissue growth to generate a complex and fully functional organ. However, organogenesis is not solely driven by genetic inputs, as the development of several organ systems requires their own functionality. This theme is particularly evident in the developing heart as progression of cardiac development is accompanied by increased and altered hemodynamic forces. In the absence or disruption of these forces, heart development is abnormal, suggesting that the heart must sense these changes and respond appropriately. Here, we discuss concepts of how embryonic heart function contributes to heart development using lessons learned mostly from studies in zebrafish., (© 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
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37. Acute Pancreatitis in the Pediatric Intensive Care Unit.
- Author
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Goday PS, Wakeham M, Kuhn EM, Collins MM, and Werlin SL
- Subjects
- Adolescent, Child, Child, Preschool, Female, Humans, Length of Stay, Male, Patient Discharge, Prognosis, Respiration, Artificial, Retrospective Studies, Severity of Illness Index, Hospitalization, Intensive Care Units, Pediatric, Pancreatitis diagnosis, Pancreatitis mortality, Pancreatitis therapy
- Abstract
Aim: The aim of this study is to describe the demographics and outcomes of children with a discharge diagnosis of acute pancreatitis (AP) from the pediatric intensive care unit (PICU)., Methods: Data for this retrospective cohort study were obtained from a multisite, clinical PICU database. PICU discharges with a primary or secondary diagnosis of AP (SAP) between 2009 and 2013 from 113 centers were reviewed. We also obtained the Pediatric Index of Mortality 2 Risk of Mortality (PIM2ROM), an indicator of the severity of illness., Results: Of 360,162 PICU discharges, 2026 with a diagnosis of AP were analyzed further (0.56%)-331 had a primary diagnosis of AP, whereas 1695 had a SAP. Among children with primary AP, median PIM2ROM was 1.0% (interquartile range [IQR] 0.8%-1.4%). Fifty-five children with primary AP (16.6%) required mechanical ventilation (MV) for a median of 3.8 days (IQR 1.0-9.3). The length of stay (LOS) in PICU was a median of 2.95 days (IQR 1.53-5.90). Only 1 patient died (mortality 0.3%). Among children with secondary AP, median PIM2ROM was 1.1% (IQR 0.8%-4.0%). A total of 711 children (42.0%) with secondary AP required MV for a median of 5.8 days (IQR 1.8-14.0). PICU LOS was a median of 4.43 days (IQR 1.84-11.22). There were 115 deaths in this group (mortality 6.8%). Median PIM2ROM, PICU LOS, mortality (all P < 0.001), and length of MV (P = 0.035) were significantly greater in children with secondary AP than with primary AP., Conclusions: Unlike in adult series, children with AP rarely die. Patients with secondary AP experience more morbidity and mortality than patients with primary AP.
- Published
- 2015
- Full Text
- View/download PDF
38. Claudin-10 is required for relay of left-right patterning cues from Hensen's node to the lateral plate mesoderm.
- Author
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Collins MM, Baumholtz AI, Simard A, Gregory M, Cyr DG, and Ryan AK
- Subjects
- Actin Cytoskeleton metabolism, Animals, Chick Embryo, Claudins biosynthesis, Claudins genetics, Gene Expression, Gene Expression Regulation, Developmental, Gene Knockdown Techniques, Heart embryology, Left-Right Determination Factors biosynthesis, Morpholinos genetics, Nodal Protein biosynthesis, Organogenesis genetics, Signal Transduction genetics, Snail Family Transcription Factors, Transcription Factors biosynthesis, Zebrafish Proteins biosynthesis, Body Patterning genetics, Claudins metabolism, Mesoderm metabolism, Organizers, Embryonic metabolism, Tight Junctions metabolism
- Abstract
Species-specific symmetry-breaking events at the left-right organizer (LRO) drive an evolutionarily-conserved cascade of gene expression in the lateral plate mesoderm that is required for the asymmetric positioning of organs within the body cavity. The mechanisms underlying the transfer of the left and right laterality information from the LRO to the lateral plate mesoderm are poorly understood. Here, we investigate the role of Claudin-10, a tight junction protein, in facilitating the transfer of left-right identity from the LRO to the lateral plate mesoderm. Claudin-10 is asymmetrically expressed on the right side of the chick LRO, Hensen's node. Gain- and loss-of-function studies demonstrated that right-sided expression of Claudin-10 is essential for normal rightward heart tube looping, the first morphological asymmetry during organogenesis. Manipulation of Claudin-10 expression did not perturb asymmetric gene expression at Hensen's node, but did disrupt asymmetric gene expression in the lateral plate mesoderm. Bilateral expression of Claudin-10 at Hensen's node prevented expression of Nodal, Lefty-2 and Pitx2c in the left lateral plate mesoderm, while morpholino knockdown of Claudin-10 inhibited expression of Snail1 in the right lateral plate mesoderm. We also determined that amino acids that are predicted to affect ion selectivity and protein interactions that bridge Claudin-10 to the actin cytoskeleton were essential for its left-right patterning function. Collectively, our data demonstrate a novel role for Claudin-10 during the transmission of laterality information from Hensen's node to both the left and right sides of the embryo and demonstrate that tight junctions have a critical role during the relay of left-right patterning cues from Hensen's node to the lateral plate mesoderm., (Copyright © 2015. Published by Elsevier Inc.)
- Published
- 2015
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39. Are there conserved roles for the extracellular matrix, cilia, and junctional complexes in left-right patterning?
- Author
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Collins MM and Ryan AK
- Subjects
- Animals, Cell Adhesion, Cell Communication, Cell Polarity, Epithelium metabolism, Humans, Morphogenesis physiology, Body Patterning physiology, Cilia metabolism, Extracellular Matrix metabolism, Intercellular Junctions metabolism
- Abstract
Many different types of molecules have essential roles in patterning the left-right axis and directing asymmetric morphogenesis. In particular, the relationship between signaling molecules and transcription factors has been explored extensively. Another group of proteins implicated in left-right patterning are components of the extracellular matrix, apical junctions, and cilia. These structural molecules have the potential to participate in the conversion of morphogenetic cues from the extracellular environment into morphogenetic patterning via their interactions with the actin cytoskeleton. Although it has been relatively easy to temporally position these proteins within the hierarchy of the left-right patterning pathway, it has been more difficult to define how they mechanistically fit into these pathways. Consequently, our understanding of how these factors impart patterning information to influence the establishment of the left-right axis remains limited. In this review, we will discuss those structural molecules that have been implicated in early phases of left-right axis development., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2014
- Full Text
- View/download PDF
40. Treatment of pediatric restless legs syndrome.
- Author
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Amos LB, Grekowicz ML, Kuhn EM, Olstad JD, Collins MM, Norins NA, and D'Andrea LA
- Subjects
- Adolescent, Amines therapeutic use, Analgesics therapeutic use, Anticonvulsants therapeutic use, Antioxidants therapeutic use, Benzothiazoles therapeutic use, Child, Child, Preschool, Clonidine therapeutic use, Cyclohexanecarboxylic Acids therapeutic use, Dopamine Agonists therapeutic use, Drug Therapy, Combination methods, Female, Gabapentin, Humans, Indoles therapeutic use, Male, Melatonin therapeutic use, Mental Disorders complications, Pediatrics, Polysomnography methods, Pramipexole, Restless Legs Syndrome complications, Retrospective Studies, Sleep Wake Disorders complications, Treatment Outcome, gamma-Aminobutyric Acid therapeutic use, Iron therapeutic use, Restless Legs Syndrome drug therapy
- Abstract
Objective: The primary aim was to determine if iron supplementation effectively treats children with restless legs syndrome (RLS), the time to improvement or resolution of symptoms, and patient characteristics (family history of RLS, secondary sleep disorders, medical diagnoses, and/or mental health diagnoses) that may affect outcome. METHODS.: This was a retrospective chart review of children between 5 and 18 years old who were diagnosed with RLS at the pediatric sleep disorders clinic at Children's Hospital of Wisconsin in Milwaukee, Wisconsin. Documented RLS treatment approaches included supplemental iron, nonpharmacologic interventions, melatonin, gabapentin, clonidine, and dopamine agonists (pramipexole and ropinirole)., Results: Ninety-seven children were diagnosed with RLS; 60.8% of children were between 5 and 11 years old. Most children (65%) received iron either as monotherapy or in combination with other treatments. Approximately 80% of the children who received iron and had follow-up had improvement or resolution of their symptoms. The median baseline ferritin level was 22.7 ng/mL, and 71% of children had a ferritin level less than 30 ng/mL. The median time to improvement or resolution of symptoms was 3.8 months., Conclusions: Supplemental iron as monotherapy or in combination with other treatments is effective in treating pediatric RLS. A prospective study could help determine if the initial ferritin level and degree of change in the ferritin level impact response to iron treatment. It is also important to study the long-term outcomes in these patients.
- Published
- 2014
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41. Unhealthy days and quality of life in Irish patients with diabetes.
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Clifford EL, Collins MM, Buckley CM, Fitzgerald AP, and Perry IJ
- Subjects
- Adult, Cross-Sectional Studies, Diabetes Mellitus pathology, Female, Health Status, Humans, Ireland, Male, Middle Aged, Surveys and Questionnaires, Young Adult, Diabetes Mellitus physiopathology, Quality of Life
- Abstract
Objectives: To study the determinants of health-related quality of life (HRQoL) in Irish patients with diabetes using the Centres for Disease Controls' (CDC's) 'Unhealthy Days' summary measure and to assesses the agreement between this generic HRQoL measure and the disease-specific Audit of Diabetes Dependant Quality of Life (ADDQoL) measure., Research Design and Methods: Data were analysed from the Diabetes Quality of Life Study, a cross-sectional study of 1,456 people with diabetes in Ireland (71% response rate). Unhealthy days were assessed using the CDC's 'Unhealthy days' summary measure. Quality of life (QoL) was also assessed using the ADDQoL measure. Analyses were conducted primarily using logistic regression. The agreement between the two QoL instruments was measured using the kappa co-efficient., Results: Participants reported a median of 2 unhealthy days per month. In multivariate analyses, female gender (P = 0.001), insulin use (P = 0.030), diabetes complications (P = <0.001) were significantly associated with more unhealthy days. Older patients had fewer unhealthy days per month (P = 0.003). Agreement between the two measures of QoL (unhealthy days measure and ADDQoL) was poor, Kappa = 0.234., Conclusions: The findings highlight the determinants of HRQoL in patients with diabetes using a generic HRQoL summary measure. The 'Unhealthy Days' and the ADDQoL have poor agreement, therefore the 'Unhealthy Days' summary measure may be assessing a different construct. Nonetheless, this study demonstrates that the generic 'Unhealthy Days' summary measure can be used to detect determinants of HRQoL in patients with diabetes.
- Published
- 2013
- Full Text
- View/download PDF
42. Contained left ventricular free wall rupture: evaluation by ERNA & echocardiography.
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Collins MM, Jain D, and Grewal RS
- Subjects
- Aneurysm, False physiopathology, Aneurysm, False surgery, Angiocardiography, Cardiac Catheterization, Diastole, Heart Rupture physiopathology, Heart Rupture surgery, Heart Ventricles surgery, Humans, Male, Middle Aged, Radionuclide Imaging, Systole, Echocardiography methods, Heart Rupture diagnostic imaging, Heart Ventricles diagnostic imaging
- Published
- 2013
- Full Text
- View/download PDF
43. Claudin family members exhibit unique temporal and spatial expression boundaries in the chick embryo.
- Author
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Collins MM, Baumholtz AI, and Ryan AK
- Abstract
The claudin family of proteins are integral components of tight junctions and are responsible for determining the ion specificity and permeability of paracellular transport within epithelial and endothelial cell layers. Several members of the claudin family have been shown to be important during embryonic development and morphogenesis. However, detailed embryonic expression patterns have been described for only a few claudins. Here, we provide a phylogenetic analysis of the chicken claudins and a comprehensive analysis of their mRNA expression profiles. We found that claudin family members exhibit both overlapping and unique expression patterns throughout development. Especially striking were the distinct expression boundaries observed between neural and non-neural ectoderm, as well as within ectodermal derivatives. Claudins were also expressed in endodermally-derived tissues, including the anterior intestinal portal, pharynx, lung and pancreas and in mesodermally derived tissues such as the kidney, gonad and heart. The overlapping zones of claudin expression observed in the chick embryo may confer distinct domains of ion permeability within the early epiblast and in epithelial, mesodermal and endothelial derivatives that may ultimately influence embryonic patterning and morphogenesis during development.
- Published
- 2013
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44. Claudin-5 expression in the vasculature of the developing chick embryo.
- Author
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Collins MM, Baumholtz AI, and Ryan AK
- Subjects
- Amino Acid Sequence, Animals, Chick Embryo, Claudin-5 genetics, Cloning, Molecular, DNA, Complementary genetics, DNA, Complementary isolation & purification, Ectoderm embryology, Gene Expression Regulation, Developmental, In Situ Hybridization, Molecular Sequence Data, Organogenesis genetics, Phylogeny, Tight Junctions metabolism, Claudin-5 metabolism, Embryonic Development genetics
- Abstract
The claudin family of proteins are integral components of tight junctions and are responsible for determining the ion specificity and permeability of paracellular transport within epithelial and endothelial cell layers. Studies in human, mouse, Xenopus, and zebrafish have shown that only a limited number of claudins are expressed in endothelial cells. Here, we report the expression pattern of Claudin-5 during chick development. Between HH stage 4 and 6 Claudin-5 expression was observed exclusively in extraembryonic tissue. Claudin-5 expression was not observed in the embryo until HH stage 8, coincident with the onset of embryonic vascularization. Claudin-5 expression was maintained in the developing vasculature in the embryonic and extraembryonic tissue throughout organogenesis (HH stage 19-35), including the vasculature of the ectoderm and of organs derived from the mesoderm and endoderm lineages. These data describe a conserved expression pattern for Claudin-5 in the endothelial tight junction barrier and is the first report of the onset of Claudin-5 expression in a vertebrate embryo., (Copyright © 2012. Published by Elsevier B.V.)
- Published
- 2012
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45. Manipulating claudin expression in avian embryos.
- Author
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Collins MM and Ryan AK
- Subjects
- Animals, Chick Embryo, Electroporation methods, Immunohistochemistry methods, In Situ Hybridization methods, Microinjections methods, Claudins metabolism, Epithelial-Mesenchymal Transition physiology, Gene Expression Regulation, Developmental physiology, Morphogenesis physiology, Tight Junctions metabolism
- Abstract
Since the discovery of Claudin-1 and -2 by Tsukita and colleagues in the late 1990s [Furuse et al. J Cell Biol 141:1539-50,1998], claudin family members have been found to have critical roles in maintaining the integrity of epithelial and endothelial tight junctions [Furuse and Moriwaki Ann N Y Acad Sci 1165:58-61, 2009; Morita et al. Proc Natl Acad Sci USA 96:511-6, 1999; Tsukita and Furuse Ann N Y Acad Sci 915:129-35, 2000; Turksen and Troy J Cell Sci 117:2435-47, 2004]. The properties of distinct claudin family members in tight junction permeability and specificity have been extensively studied in vitro using cell culture models. In vivo, claudin family members are dynamically regulated during embryogenesis and alterations in their expression patterns can have detrimental effects on the formation and physiological function of the tissues in which they are expressed. The chick embryo provides an excellent system to dissect the roles of specific family members in vivo and to explore the effects of modulating claudin expression during the epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions that are associated with tissue morphogenesis and differentiation. We are using the chick embryo to understand the roles of the claudin family of tight junction proteins during gastrulation and left-right patterning during embryogenesis. Here, we describe methodologies for manipulating claudin gene expression in specific target tissues during chick embryogenesis.
- Published
- 2011
- Full Text
- View/download PDF
46. Expression patterns of hormones, signaling molecules, and transcription factors during adenohypophysis development in the chick embryo.
- Author
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Parkinson N, Collins MM, Dufresne L, and Ryan AK
- Subjects
- Animals, Body Patterning genetics, Body Patterning physiology, Cell Differentiation genetics, Cell Differentiation physiology, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gonadotrophs cytology, Gonadotrophs metabolism, Gonadotrophs physiology, Intracellular Signaling Peptides and Proteins metabolism, Lactotrophs cytology, Lactotrophs metabolism, Lactotrophs physiology, Melanotrophs cytology, Melanotrophs metabolism, Melanotrophs physiology, Models, Biological, Pituitary Gland, Anterior metabolism, Pituitary Hormones metabolism, RNA, Messenger analysis, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction, Thyrotrophs cytology, Thyrotrophs metabolism, Thyrotrophs physiology, Transcription Factors metabolism, Chick Embryo metabolism, Intracellular Signaling Peptides and Proteins genetics, Pituitary Gland, Anterior embryology, Pituitary Hormones genetics, Transcription Factors genetics
- Abstract
The chick embryo is an ideal model to study pituitary cell-type differentiation. Previous studies describing the temporal appearance of differentiated pituitary cell types in the chick embryo are contradictory. To resolve these controversies, we used RT-PCR to define the temporal onset and in situ hybridization and immunohistochemistry to define the spatial localization of hormone expression within the pituitary. RT-PCR detected low levels of Fshbeta (gonadotropes) and Pomc (corticotropes, melanotropes) mRNA at E4 and Gh (somatotropes), Prl (lactotropes), and Tshbeta (thyrotropes) mRNA at E8. For all hormones, sufficient accumulation of mRNA and/or protein to permit detection by in situ hybridization or immunohistochemistry was observed approximately 3 days later and in all cases corresponded to a notable increase in RT-PCR product. We also describe the expression patterns of signaling (Bmp2, Bmp4, Fgf8, Fgf10, Shh) and transcription factors (Pitx1, Pitx2, cLim3) known to be important for pituitary organogenesis in other model organisms.
- Published
- 2010
- Full Text
- View/download PDF
47. The ClC-3 Cl-/H+ antiporter becomes uncoupled at low extracellular pH.
- Author
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Matsuda JJ, Filali MS, Collins MM, Volk KA, and Lamb FS
- Subjects
- Animals, Aorta cytology, Cell Compartmentation physiology, Cell Line, Chloride Channels genetics, Glutamic Acid genetics, Glutamic Acid metabolism, Green Fluorescent Proteins genetics, Humans, Kidney cytology, Membrane Potentials drug effects, Membrane Potentials physiology, Mesylates pharmacology, Mice, Mice, Mutant Strains, Muscle, Smooth, Vascular cytology, Mutagenesis, Patch-Clamp Techniques, RNA, Small Interfering, Sulfhydryl Reagents pharmacology, Acids metabolism, Chloride Channels physiology, Chlorides metabolism, Hydrogen metabolism, Hydrogen-Ion Concentration
- Abstract
Adenovirus expressing ClC-3 (Ad-ClC-3) induces Cl(-)/H(+) antiport current (I(ClC-3)) in HEK293 cells. The outward rectification and time dependence of I(ClC-3) closely resemble an endogenous HEK293 cell acid-activated Cl(-) current (ICl(acid)) seen at extracellular pH
- Published
- 2010
- Full Text
- View/download PDF
48. Quality of life and quality of care in patients with diabetes experiencing different models of care.
- Author
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Collins MM, O'Sullivan T, Harkins V, and Perry IJ
- Subjects
- Adult, Cross-Sectional Studies, Diabetes Mellitus psychology, Diabetes Mellitus, Type 1 physiopathology, Diabetes Mellitus, Type 1 psychology, Diabetes Mellitus, Type 1 therapy, Diabetes Mellitus, Type 2 physiopathology, Diabetes Mellitus, Type 2 psychology, Diabetes Mellitus, Type 2 therapy, Employment, Family Practice standards, Female, Hospitalization, Humans, Male, Marital Status, Middle Aged, Primary Health Care standards, Quality Assurance, Health Care, Surveys and Questionnaires, Young Adult, Diabetes Mellitus physiopathology, Diabetes Mellitus therapy, Quality of Life
- Abstract
Objective: To study variation in quality of life and quality of care in patients with diabetes experiencing three different models of care: traditional hospital care, hospital/general practitioner (GP) shared care, and structured GP care., Research Design and Methods: A cross-sectional study involving 1,456 patients with diabetes (71% response rate) was conducted. Quality of life was assessed with the Audit of Diabetes-Dependent Quality of Life (ADDQoL) instrument and quality of care with a 10-point process-of-care report card., Results: The adjusted odds ratio (OR) for a high (upper quartile) ADDQoL score was significantly increased in the structured care relative to the traditional hospital care group (OR 1.7 [95% CI 1.2-2.5]). A significantly higher proportion of structured GP care patients reported compliance with seven or more key process-of-care measures compared with the other models of care., Conclusions: Diabetes quality of life may be enhanced when care is provided in a primary care setting without compromising quality of care.
- Published
- 2009
- Full Text
- View/download PDF
49. Self-care coping strategies in people with diabetes: a qualitative exploratory study.
- Author
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Collins MM, Bradley CP, O'Sullivan T, and Perry IJ
- Abstract
Background: The management of diabetes self-care is largely the responsibility of the patient. With more emphasis on the prevention of complications, adherence to diabetes self-care regimens can be difficult. Diabetes self-care requires the patient to make many dietary and lifestyle changes. This study will explore patient perceptions of diabetes self-care, with particular reference to the burden of self-care and coping strategies among patients., Methods: A maximum variation sample of 17 patients was selected from GP practices and diabetes clinics in Ireland to include patients with types 1 and 2 diabetes, various self-care regimens, and a range of diabetes complications. Data were collected by in-depth interviews; which were tape-recorded and transcribed. The transcripts were analysed using open and axial coding procedures to identify main categories, and were reviewed by an independent corroborator. Discussion of the results is made in the theoretical context of the health belief, health value, self-efficacy, and locus of control frameworks., Results: Patients' perceptions of their self-care varied on a spectrum, displaying differences in self-care responsibilities such as competence with dietary planning, testing blood sugar and regular exercise. Three patient types could be distinguished, which were labeled: "proactive manager," a patient who independently monitors blood glucose and adjusts his/her self-care regime to maintain metabolic control; "passive follower," a patient who follows his/her prescribed self-care regime, but does not react autonomously to changes in metabolic control; and "nonconformist," a patient who does not follow most of his/her prescribed self-care regimen., Conclusion: Patients have different diabetes self-care coping strategies which are influenced by their self-care health value and consequently may affect their diet and exercise choices, frequency of blood glucose monitoring, and compliance with prescribed medication regimens. Particular attention should be paid to the patient's self-care coping strategy, and self-care protocols should be tailored to complement the different patient types.
- Published
- 2009
- Full Text
- View/download PDF
50. Anxiety and depression symptoms in patients with diabetes.
- Author
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Collins MM, Corcoran P, and Perry IJ
- Subjects
- Adult, Aged, Comorbidity, Cross-Sectional Studies, Delivery of Health Care methods, Diabetes Mellitus, Type 1 epidemiology, Diabetes Mellitus, Type 1 therapy, Diabetes Mellitus, Type 2 epidemiology, Diabetes Mellitus, Type 2 therapy, Female, Humans, Ireland epidemiology, Male, Middle Aged, Prevalence, Psychiatric Status Rating Scales, Risk Factors, Young Adult, Anxiety Disorders epidemiology, Depressive Disorder epidemiology, Diabetes Mellitus, Type 1 psychology, Diabetes Mellitus, Type 2 psychology
- Abstract
Aims: To identify the prevalence and major determinants of anxiety and depression symptoms in patients with diabetes., Methods: A cross-sectional study of 2049 people with Types 1 and 2 diabetes, selected from patients experiencing three different models of care in Ireland: (i) traditional mixed care; (ii) hospital/general practitioner (GP) shared care; (iii) structured GP care. Anxiety and depression symptoms were assessed with the Hospital Anxiety and Depression Scale (HADS). Analyses were conducted primarily using logistic regression with adjustment for relevant confounders., Results: The overall response rate was 71% (n = 1456). Based on the HADS, there was evidence of high levels of anxiety and depression symptoms in patients with diabetes; 32.0% (95% confidence interval = 29.5-34.6%) exceeded the HADS cut-off score of 'mild to severe' anxiety and 22.4% (95% confidence interval = 20.2-24.7%) exceeded the HADS cut-off score of 'mild to severe' depression. Diabetes complications, smoking, uncertainty about glycaemic control and being an ex-drinker or a heavy drinker were risk factors for both higher anxiety and depression scores in multivariate analysis. Female gender and poor glycaemic control were risks factors associated only with higher anxiety scores. Higher socio-economic status and older age were protective factors for lower anxiety and depression scores. Type of diabetes, insulin use, marital status and models of care were not significant predictors of anxiety and depression scores., Conclusions: The prevalence of anxiety and depression symptoms in patients with diabetes is considerably higher than in general population samples. These data serve as a benchmark for the prevalence of anxiety and depression symptoms in patients with diabetes.
- Published
- 2009
- Full Text
- View/download PDF
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