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INTRODUCTION: Messenger ribonucleic acid (mRNA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines have been associated with myocarditis/pericarditis, especially in young males. We evaluated the risk of myocarditis/pericarditis following mRNA vaccines by brand, age, sex and dose number in Singapore. METHODS: Adverse event reports of myocarditis/pericarditis following mRNA vaccines received by the Health Sciences Authority from 30 December 2020 to 25 July 2022 were included, with a data lock on 30 September 2022. Case adjudication was done by an independent panel of cardiologists using the US Centers for Disease Control and Prevention case definition. Reporting rates were compared with expected rates using historical data from 2018 to 2020. RESULTS: Of the 152 adjudicated cases, males comprised 75.0%. The median age was 30 years. Most cases occurred after Dose 2 (49.3%). The median time to onset was 2 days. Reporting rates were highest in males aged 12-17 years for both primary series (11.5 [95% confidence interval [CI] 6.7-18.4] per 100,000 doses, post-Dose 2) and following booster doses (7.1 [95% CI 3.0-13.9] per 100,000 doses). In children aged 5-11 years, myocarditis remained very rare (0.2 per 100,000 doses). The reporting rates for Booster 1 were generally similar or lower than those for Dose 2. CONCLUSIONS: The risk of myocarditis/pericarditis with mRNA vaccines was highest in adolescent males following Dose 2, and this was higher than historically observed background rates. Most cases were clinically mild. The risk of myocarditis should be weighed against the benefits of receiving an mRNA vaccine, keeping in mind that SARS-CoV-2 infections carry substantial risks of myocarditis/pericarditis, as well as the evolving landscape of the disease.
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Listeria monocytogenes can grow under stressful conditions and contaminate various food categories. Progresss in DNA sequencing-based identification methods, such as multi-locus sequence typing (MLST) now allow for more accurate characterization of pathogens. L. monocytogenes MLST genetic diversity is reflected by the different prevalence of the "clonal complexes" (CCs) in foods or infections. Better understanding of the growth potentials of L. monocytogenes is essential for quantitative risk assessment and efficient detection across CCs genetic diversity. Using optical density measurements taken with an automated spectrophotometer, we compared the maximal growth rate and lag phase of 39 strains from 13 different CCs and various food origins, in 3 broths mimicking stresful food conditions (8 °C, aw 0.95 and pH5) and in ISO Standard enrichment broths (Half Fraser and Fraser). This is important as growth could influence risk through pathogen multiplication in food. Besides, enrichment problems could lead to a lack of detection of some CCs. Despite small differences highlighting natural intraspecific variability, our results show that growth performances of L. monocytogenes strains under the conditions tested in selective and non-selective broth do not appear to be strongly correlated to CCs and cannot explain higher CC "virulence" or prevalence.
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Listeria monocytogenes , Listeria monocytogenes/génétique , Typage par séquençage multilocus , Microbiologie alimentaire , Analyse de séquence d'ADN , Variation génétiqueRÉSUMÉ
PROBLEM: Graduate medical education programs and national organizations are becoming more involved in promoting trainee financial wellness. Current literature reports residents have poor financial knowledge, high debt levels, low concern about their finances, and deficits in financial preparedness, but there has been little published on best practices for implementing financial wellness programs for residents or measuring meaningful outcomes of such programs. APPROACH: From June 2017 to 2019, the authors invited 277 internal medicine residents from the Stony Brook University Hospital, Montefiore Medical Center, and Johns Hopkins Bayview Medical Center residency programs to participate in financial wellness programs. Each institution held at least one 90-minute financial planning session; Stony Brook also had biannual financial wellness check-ins. Participants were invited to complete a presession, an immediate postsession, and a year-end survey to assess changes in financial planning behaviors. OUTCOMES: Survey response rates were 49% (135/277) for the presession survey, 47% (130/277) for the immediate postsession survey, and 22% (61/277) for the year-end survey. Ninety-six percent (125/130) found the sessions helpful and 98% (120/123) recommended continuing the program in the future. At year-end, the most frequent completed financial planning actions prompted by the session included saving emergency funds, creating a monthly budget, consolidating loans via the Public Service Loan Forgiveness program, contributing to retirement savings, and participating in an employer's retirement plan. Residents liked that some sessions were during intern orientation before the selection of retirement plans. Postgraduate year (PGY) 1 residents were more likely to complete positive financial planning actions and to agree or strongly agree that the session prompted them to take financial planning actions than PGY-2 and PGY-3 residents. NEXT STEPS: While financial wellness programs are well received by internal medicine residents, more robust evidence is needed on curricular delivery methods and program features that promote positive financial planning behaviors.
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Gestion financière , Internat et résidence , Enseignement spécialisé en médecine , Promotion de la santé , Humains , Enquêtes et questionnairesRÉSUMÉ
Soft robots provide compliant object-machine interactions, but they exhibit insufficient material stability, which restricts them from working in harsh environments. Herein, we developed a class of soft robotic skins based on two-dimensional materials (2DMs) and gelatin hydrogels, featuring skin-like multifunctionality (stretchability, thermoregulation, threat protection, and strain sensing). The 2DM-integrated hydrogel (2DM/H) skins enabled soft robots to execute designated missions in the presence of high levels of heat and various environmental threats while maintaining mild machine temperatures. Via adopting different 2DMs (graphene oxide (GO), montmorillonite (MMT), and titanium carbide (MXene)), the 2DM/H-protected robots were able to perform soft grasping in organic liquids (GO/H) and open fire (MMT/H), and in the presence of electromagnetic radiation and biocontamination (MXene/H). Through blending MXene nanosheets into gelatin, the MXene-blended hydrogel (M-H) skin became strain sensitive, and a GO/M-H gripper exhibited the high-level integration of skin-mimicking capabilities. Finally, we incorporated 2DM/H skins onto an origami-inspired walker robot and a soft batoid-like robot to execute vision-guided searching in fire and underwater locomotion/navigation in chemical spills.
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Hydrogels , Robotique , Gélatine , PeauRÉSUMÉ
Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is initiated by binding of the viral Spike protein to host receptor angiotensin-converting enzyme 2 (ACE2), followed by fusion of viral and host membranes. Although antibodies that block this interaction are in emergency use as early coronavirus disease 2019 (COVID-19) therapies, the precise determinants of neutralization potency remain unknown. We discovered a series of antibodies that potently block ACE2 binding but exhibit divergent neutralization efficacy against the live virus. Strikingly, these neutralizing antibodies can inhibit or enhance Spike-mediated membrane fusion and formation of syncytia, which are associated with chronic tissue damage in individuals with COVID-19. As revealed by cryoelectron microscopy, multiple structures of Spike-antibody complexes have distinct binding modes that not only block ACE2 binding but also alter the Spike protein conformational cycle triggered by ACE2 binding. We show that stabilization of different Spike conformations leads to modulation of Spike-mediated membrane fusion with profound implications for COVID-19 pathology and immunity.
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Anticorps neutralisants/composition chimique , Cellules géantes/métabolisme , Glycoprotéine de spicule des coronavirus/composition chimique , Angiotensin-converting enzyme 2/composition chimique , Angiotensin-converting enzyme 2/génétique , Angiotensin-converting enzyme 2/immunologie , Angiotensin-converting enzyme 2/métabolisme , Animaux , Anticorps neutralisants/immunologie , Anticorps neutralisants/métabolisme , Complexe antigène-anticorps/composition chimique , Complexe antigène-anticorps/métabolisme , Sites de fixation , Cellules CHO , COVID-19/anatomopathologie , COVID-19/virologie , Cricetinae , Cricetulus , Cryomicroscopie électronique , Cellules géantes/cytologie , Humains , Fusion membranaire , Banque de peptides , Liaison aux protéines , Domaines protéiques , Structure quaternaire des protéines , SARS-CoV-2/isolement et purification , SARS-CoV-2/métabolisme , Glycoprotéine de spicule des coronavirus/immunologie , Glycoprotéine de spicule des coronavirus/métabolismeRÉSUMÉ
Introduction: Although studies surveying internal medicine (IM) residency program directors identify geriatric women's health as an essential curriculum topic, there are limited published women's health curricula for IM residents. Our IM residency program performed a needs assessment, which revealed that the majority of residents were unsatisfied with our current curricula and most were not confident managing geriatric women's health. We developed and assessed a structured curriculum to improve IM residents' knowledge and confidence in addressing geriatric women's health. Methods: This 2-hour interactive workshop used the jigsaw teaching method (a cooperative learning strategy where peers deliver specific content in teams) to teach 84 categorical IM residents of all PGY levels about the diagnosis and management of menopause, osteoporosis, urinary incontinence, and abnormal uterine bleeding. Participants completed a pretest and immediate posttest to assess knowledge and confidence about the targeted topics. We compared baseline and postworkshop responses using chi-square and Wilcoxon signed rank tests. Results: Seventy-four (88%) IM residents completed the pretest, and 62 (74%) completed the posttest. Mean knowledge scores improved from 51% to 69% (p < .0001). Residents who reported feeling somewhat confident or confident in addressing women's health topics increased from 14% to 44% (p < .0001). The majority were satisfied or very satisfied with the workshop (94%) and requested additional women's health education (92%). Discussion: Our results suggest that workshops using the jigsaw teaching method can effectively increase IM resident knowledge and confidence in managing geriatric women's health.
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Internat et résidence , Sujet âgé , Attitude , Programme d'études , Femelle , Humains , Formation en interne , Santé des femmesRÉSUMÉ
In vitro antibody selection against pathogens from naïve combinatorial libraries can yield various classes of antigen-specific binders that are distinct from those evolved from natural infection1-4. Also, rapid neutralizing antibody discovery can be made possible by a strategy that selects for those interfering with pathogen and host interaction5. Here we report the discovery of antibodies that neutralize SARS-CoV-2, the virus responsible for the COVID-19 pandemic, from a highly diverse naïve human Fab library. Lead antibody 5A6 blocks the receptor binding domain (RBD) of the viral spike from binding to the host receptor angiotensin converting enzyme 2 (ACE2), neutralizes SARS-CoV-2 infection of Vero E6 cells, and reduces viral replication in reconstituted human nasal and bronchial epithelium models. 5A6 has a high occupancy on the viral surface and exerts its neutralization activity via a bivalent binding mode to the tip of two neighbouring RBDs at the ACE2 interaction interface, one in the "up" and the other in the "down" position, explaining its superior neutralization capacity. Furthermore, 5A6 is insensitive to several spike mutations identified in clinical isolates, including the D614G mutant that has become dominant worldwide. Our results suggest that 5A6 could be an effective prophylactic and therapeutic treatment of COVID-19.
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BACKGROUND: Despite increasing use of telehealth, there are limited published curricula training primary care providers in utilizing telehealth to deliver complex interdisciplinary care. OBJECTIVE: To describe and evaluate a telehealth curriculum with a longitudinal objective structured clinical examination (OSCE) to improve internal medicine residents' confidence and skills in coordinating complex interdisciplinary primary care via televisits, electronic consultation, and teleconferencing. METHODS: In 2019, 56 first- and third-year residents participated in a 3-part, 5-week OSCE training them to use telehealth to manage complex primary care. Learners conducted a standardized patient (SP) televisit in session 1, coordinated care via inter-visit e-messaging, and led a simulated interdisciplinary teleconference in session 2. Surveys measured confidence before session 1 (pre), post-session 1 (post-1), and post-session 2 (post-2). SP televisit checklists and investigators' assessment of e-messages evaluated residents' telehealth skills. RESULTS: Response rates were pre 100%, post-1 95% (53 of 56), and post-2 100%. Post-intervention, more residents were "confident/very confident" in adjusting their camera (33%, 95% CI 20-45 vs 85%, 95% CI 75-95, P < .0001), e-messaging (pre 36%, 95% CI 24-49 vs post-2 80%, 95% CI 70-91, P < .0001), and coordinating interdisciplinary care (pre 35%, 95% CI 22-47 vs post-2 84%, 95% CI 74-94, P < .0001). More residents were "likely/very likely" to use telemedicine in the future (pre 56%, 95% CI 43-69, vs post-2 79%, 95% CI 68-89, P = .001). CONCLUSIONS: A longitudinal, interdisciplinary telehealth simulation is feasible and can improve residents' confidence in using telemedicine to provide complex patient care.
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Internat et résidence , Télémédecine , Compétence clinique , Programme d'études , Humains , Soins aux patients , Simulation sur patients standardisés , Soins de santé primairesRÉSUMÉ
Suboptimal immune responses to pathogens contribute to chronic infections. One way to improve immune responses is to boost Ag presentation. In this study, we investigate the potential of the tripartite motif-containing 21 (TRIM21) pathway. TRIM21 is a ubiquitously expressed cytosolic protein that recognizes the Fc region of Abs. When Abs that are bound to pathogens enter the cell as immune complexes, binding of TRIM21 to Fc initiates downstream inflammatory signaling and targets the immune complexes for proteasomal degradation. In APCs, peptides generated by proteasomes are loaded onto MHC class I molecules to stimulate CD8 T cell responses, which are crucial for effective immunity to pathogens. We hypothesized that increasing the affinity between immune complexes and TRIM21 might markedly improve CD8 T cell responses to Ags processed by the TRIM21 pathway. Using phage display technology, we engineered the human IgG1 Fc to increase its affinity for TRIM21 by 100-fold. Adenovirus immune complexes with the engineered Fc induced greater maturation of human dendritic cells (DC) than immune complexes with unmodified Fc and stimulated increased Ag-specific CD8 T cell proliferation and IFN-γ release in cocultures of DC-PBMC. Thus, by increasing the affinity between Fc and TRIM21, Ags from immune complexes undergo enhanced cross-presentation on DC, leading to greater CD8 T cell responses. Our study reveals an approach that could potentially be used in vaccines to increase cytotoxic T cell responses against Ags that are targeted or delivered by Fc-modified Abs.
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Présentation d'antigène , Cellules dendritiques/immunologie , Monocytes/immunologie , Ribonucléoprotéines/immunologie , Lymphocytes T CD8+/cytologie , Lymphocytes T CD8+/immunologie , Cellules dendritiques/cytologie , Humains , Fragments Fc des immunoglobulines/immunologie , Immunoglobuline G/immunologie , Monocytes/cytologie , Ribonucléoprotéines/génétiqueRÉSUMÉ
BACKGROUND: Residents graduate from medical school with increasing levels of debt and also may possess poor financial knowledge and practices. Prior studies have assessed resident financial knowledge and interest in financial education, yet additional information regarding their attitudes about personal finance and financial planning could be essential for the development of relevant curricula. OBJECTIVE: We assessed baseline financial attitudes and planning behaviors of internal medicine and internal medicine-pediatrics residents in 3 geographically diverse academic programs. METHODS: A modified version of the Financial Industry Regulatory Authority National Financial Capability survey was administered anonymously to residents in 3 programs in spring 2017. Outcomes included levels of educational debt, positive financial planning behaviors, perception of finances and debt, and education about personal finance. RESULTS: Response rate was 62% (184 of 298). Rates of educational debt were high, with 81% (149 of 184) of respondents reporting educational debt, and the majority owing more than $100,000. Residents' financial practices were variable, and residents could be grouped into 1 of 3 categories-concerned-engaged, concerned-unengaged, and unconcerned-unengaged-based on their engagement with debt and financial management. Residents with high debt (> $250,000) had a bimodal distribution of respondents who strongly agreed and those who strongly disagreed they were concerned about debt. CONCLUSIONS: Resident financial attitudes and practices are variable, ranging from highly engaged residents actively managing their financial wellness to unengaged residents who have low concern, despite high educational debt.
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Internat et résidence/économie , Médecins/psychologie , Soutien financier à la formation/statistiques et données numériques , Adulte , Attitude du personnel soignant , Femelle , Humains , Médecine interne/enseignement et éducation , Mâle , Pédiatrie/enseignement et éducation , Enquêtes et questionnaires , États-UnisRÉSUMÉ
The ability of Listeria monocytogenes to adhere to and persist on surfaces for months or even years may be responsible for its transmission from contaminated surfaces to food products. Hence the necessity to find effective means to prevent the establishment of L. monocytogenes in food processing environments. The aim of this study was to assess, through a fractional experimental design, the environmental factors that could affect the survival of L. monocytogenes cells on surfaces to thereby prevent the persistence of this pathogen in conditions mimicking those encountered in food processing plants: culture with smoked salmon juice or meat exudate, use of two materials with different hygiene status, biofilm of L. monocytogenes in pure-culture or dual-culture with a Pseudomonas fluorescens strain, application of a drying step after cleaning and disinfection (C&D) and comparison of two strains of L. monocytogenes. Bacterial survival was assessed by culture, qPCR to quantify total cells, and propidium monoazide coupled with qPCR to quantify viable cells and highlight viable but non-culturable (VBNC) cells. Our results showed that failure to apply C&D causes cell persistence on surfaces. Moreover, the sanitation procedure leads only to a loss of culturability and appearance of VBNC populations. However, an additional daily drying step after C&D optimises the effectiveness of these procedures to reduce culturable populations. Our results reinforce the importance to use molecular tools to monitor viable pathogens in food processing plants to avoid underestimating the amounts of cells using only methods based on cell culture.
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Biofilms/croissance et développement , Dessiccation/méthodes , Désinfection/méthodes , Contamination des aliments/prévention et contrôle , Manipulation des aliments/méthodes , Listeria monocytogenes/croissance et développement , Pseudomonas fluorescens/croissance et développement , Adhérence bactérienne , Microbiologie alimentaire , Industrie de la transformation des aliments/instrumentation , Listeria monocytogenes/physiologie , Viande/microbiologie , Pseudomonas fluorescens/physiologieRÉSUMÉ
BACKGROUND: The use of Complementary and Alternative Medicine (CAM) has been increasing over the years. A recent review of adverse event reports (AERs) associated with CAM in Singapore found a notable number of AERs submitted. The objectives of this study are to analyse hepatotoxicity cases associated with CAM in Singapore based on spontaneous adverse event reporting to the Health Sciences Authority (HSA), and to highlight safety signals for specific herbal ingredients. METHODS: AERs associated with CAM and hepatotoxicity submitted to the Vigilance and Compliance Branch (VCB) of the HSA from 2009 to 2014 were compiled. The following information was extracted and analysed: Demographic information; time to onset; hospitalisation status; outcome; type of hepatotoxicity; ingredients of CAM, and the total daily doses (TDD); concurrent western medicines and health supplements; and reporter details. RESULTS: Fifty-seven reports were eligible for analysis. Thirty-five (61.4 %) cases involved Traditional Chinese Medicine (TCM). The Roussel Uclaf Causality Assessment Method was applied in 29 (82.9 %) of these cases, and the median score was 4 (range: 1-8). Chai Hu (Radix bupleuri) was suspected in 11 (31.4 %) cases. TDDs of most ingredients were within recommended doses of the Chinese Pharmacopoeia. CONCLUSIONS: Drug-induced liver injury is still poorly understood and more objective assessments are warranted. Reporting of adverse events should be strongly advocated to facilitate future analyses and the understanding of risk-benefit profiles of CAM.
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Lésions hépatiques dues aux substances/épidémiologie , Thérapies complémentaires/effets indésirables , Thérapies complémentaires/statistiques et données numériques , Adolescent , Adulte , Enfant , Enfant d'âge préscolaire , Femelle , Humains , Nourrisson , Nouveau-né , Mâle , Adulte d'âge moyen , Études rétrospectives , Singapour/épidémiologie , Jeune adulteRÉSUMÉ
Plasma samples collected in tubes containing separator gels have replaced serum samples for most chemistry tests in many hospital and commercial laboratories. Use of plasma samples for blood tests in the dialysis population eliminates delays in sample processing while waiting for clotting to complete, laboratory technical issues associated with fibrin formation, repeat sample collection, and patient care issues caused by delay of results because of incompletely clotted specimens. Additionally, a larger volume of plasma is produced than serum for the same amount of blood collected. Plasma samples are also acceptable for most chemical tests involved in the care of patients with ESRD. This information becomes very important when United States regulatory requirements for ESRD inadvertently limit the type of sample that can be used for government reporting, quality assessment, and value-based payment initiatives. In this narrative, we summarize the renal community experience and how the subsequent resolution of the acceptability of phosphorus levels measured from serum and plasma samples may have significant implications in the country's continued development of a value-based Medicare ESRD Quality Incentive Program.
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Défaillance rénale chronique/sang , Phosphore/analyse , Plasma sanguin/composition chimique , Dialyse rénale/normes , Sérum/composition chimique , Humains , Défaillance rénale chronique/thérapie , Amélioration de la qualité , Indicateurs qualité santé , États-UnisRÉSUMÉ
Although some investigations have assessed the barriers to prostate cancer screening among African-American men, limited data are available regarding such practices in similar African-origin populations. Key informant interviews were employed to obtain a range of perspectives pertaining to the healthcare practices of African-Barbadian men and to identify factors that obstruct prostate cancer screening in Barbados, West Indies. Gender-related perceptions were identified as a major obstruction to prostate cancer screening. Additionally, concerns about privacy, taking time away from work and mistrust of the medical community were reported as themes impeding the healthcare-seeking behaviors of African-Barbadian men. System-level barriers included limitations in access to care and ineffective dissemination of health information. Findings from this study suggest that targeted efforts aimed at modifying socio-cultural perceptions may assist in improving prostate cancer screening and general healthcare-seeking practices of African-Barbadian men and others who share similar beliefs.
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Connaissances, attitudes et pratiques en santé , Acceptation des soins par les patients , Tumeurs de la prostate/diagnostic , Adulte , Sujet âgé , Barbade , Recherche participative basée sur la communauté , Femelle , Humains , Mâle , Adulte d'âge moyen , Recherche qualitativeRÉSUMÉ
BACKGROUND: To date, no study has compared the clinical characteristics, malignancy associations, and treatment of dermatomyositis in predominantly Caucasian vs. Asian populations. MATERIALS AND METHODS: This prospective study was conducted to compare clinical characteristics of dermatomyositis, its relationship to malignancy, and treatment between two tertiary medical centers in the USA and Singapore. A total of 19 newly-diagnosed patients in the USA and 15 patients in Singapore were enrolled. Dermatomyositis or amyopathic dermatomyositis were diagnosed based on clinical assessment, skin and muscle biopsies, and muscle testing. RESULTS: Ninety-five percent of patients in the USA group were of Caucasian descent, while 93% of patients in the Singapore group were of Chinese descent. Both groups were predominantly female. Pruritus was the most common initial symptom reported in both groups, while periungual erythema and Gottron's papules were the most common skin presentations. Heliotrope eruption was more common in the Singapore group, occurring in 80% of patients vs. 32% of patients in the USA group (P = 0.007). Three patients in the Singapore group developed a malignancy, with two of these patients having nasopharyngeal carcinoma. None of the USA patients developed malignancies in a follow- up period of 2-5 years. Immunosuppressive steroid sparing therapy with hydroxychloroquine was more frequently used in Singapore, while topical tacrolimus was more frequently used in the USA. CONCLUSION: The clinical presentations of dermatomyositis vary among different ethnic populations. Chinese patients with dermatomyositis have a significant risk for nasopharyngeal carcinoma.
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Carcinomes/complications , Dermatomyosite/traitement médicamenteux , Dermatomyosite/anatomopathologie , Immunosuppresseurs/usage thérapeutique , Tumeurs du rhinopharynx/complications , Hormones corticosurrénaliennes/usage thérapeutique , Adulte , Sujet âgé , Anticorps monoclonaux d'origine murine/usage thérapeutique , Asiatiques , Agents de maintien de la densité osseuse/usage thérapeutique , Composés du calcium/usage thérapeutique , Dermatomyosite/complications , Compléments alimentaires , Diphosphonates/usage thérapeutique , Érythème/étiologie , Femelle , Humains , Hydroxychloroquine/usage thérapeutique , Mâle , Méthotrexate/usage thérapeutique , Adulte d'âge moyen , Acide mycophénolique/analogues et dérivés , Acide mycophénolique/usage thérapeutique , Oxydes/usage thérapeutique , Études prospectives , Prurit/étiologie , Rituximab , Singapour , Tacrolimus/usage thérapeutique , Centres de soins tertiaires , États-Unis , Vitamine D/usage thérapeutique ,RÉSUMÉ
INTRODUCTION: Octamer-binding transcription factor 4 (Oct4) is a master regulator of early mammalian development. Its expression begins from the oocyte stage, becomes restricted to the inner cell mass of the blastocyst and eventually remains only in primordial germ cells. Unearthing the interactions of Oct4 would provide insight into how this transcription factor is central to cell fate and stem cell pluripotency. METHODS: In the present study, affinity-tagged endogenous Oct4 cell lines were established via homologous recombination gene targeting in embryonic stem (ES) cells to express tagged Oct4. This allows tagged Oct4 to be expressed without altering the total Oct4 levels from their physiological levels. RESULTS: Modified ES cells remained pluripotent. However, when modified ES cells were tested for their functionality, cells with a large tag failed to produce viable homozygous mice. Use of a smaller tag resulted in mice with normal development, viability and fertility. This indicated that the choice of tags can affect the performance of Oct4. Also, different tags produce a different repertoire of Oct4 interactors. CONCLUSIONS: Using a total of four different tags, we found 33 potential Oct4 interactors, of which 30 are novel. In addition to transcriptional regulation, the molecular function associated with these Oct4-associated proteins includes various other catalytic activities, suggesting that, aside from chromosome remodeling and transcriptional regulation, Oct4 function extends more widely to other essential cellular mechanisms. Our findings show that multiple purification approaches are needed to uncover a comprehensive Oct4 protein interaction network.
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Chromatographie d'affinité/méthodes , Facteur de transcription Oct-3/isolement et purification , Cartographie d'interactions entre protéines , Marqueurs d'affinité , Séquence d'acides aminés , Animaux , Technique de Western , Lignée cellulaire/composition chimique , Cellules souches embryonnaires/métabolisme , Gènes létaux , Spectrométrie de masse , Souris , Souris de souche-129 , Souris de lignée C57BL , Souris transgéniques , Données de séquences moléculaires , Facteur de transcription Oct-3/métabolisme , Cellules souches pluripotentes/métabolisme , Liaison aux protéines , Protéines de fusion recombinantes/métabolisme , Facteurs de transcription/isolement et purification , Facteurs de transcription/métabolisme , TransgènesRÉSUMÉ
Embryonic stem cells have the ability to differentiate into nearly all cell types. However, the molecular mechanism of its pluripotency is still unclear. Oct3/4, Sox2 and Nanog are important factors of pluripotency. Oct3/4 (hereafter referred to as Oct4), in particular, has been an irreplaceable factor in the induction of pluripotency in adult cells. Proteins interacting with Oct4 and Nanog have been identified via affinity purification and mass spectrometry. These data, together with iterative purifications of interacting proteins allowed a protein interaction network to be constructed. The network currently includes 77 transcription factors, all of which are interconnected in one network. In-depth studies of some of these transcription factors show that they all recruit the NuRD complex. Hence, transcription factor clustering and chromosomal remodeling are key mechanism used by embryonic stem cells. Studies using RNA interference suggest that more pluripotency genes are yet to be discovered via protein-protein interactions. More work is required to complete and curate the embryonic stem cell protein interaction network. Analysis of a saturated protein interaction network by system biology tools can greatly aid in the understanding of the embryonic stem cell pluripotency network.