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OBJECTIVE: Describe the first hybrid global simulation-based comprehensive cleft care workshop, evaluate impact on participants, and compare experiences based on in-person versus virtual attendance. DESIGN: Cross-sectional survey-based evaluation. SETTING: International comprehensive cleft care workshop. PARTICIPANTS: Total of 489 participants. INTERVENTIONS: Three-day simulation-based hybrid comprehensive cleft care workshop. MAIN OUTCOME MEASURES: Participant demographic data, perceived barriers and interventions needed for global comprehensive cleft care delivery, participant workshop satisfaction, and perceived short-term impact on practice stratified by in-person versus virtual attendance. RESULTS: The workshop included 489 participants from 5 continents. The response rate was 39.9%. Participants perceived financial factors (30.3%) the most significant barrier and improvement in training (39.8%) as the most important intervention to overcome barriers facing cleft care delivery in low to middle-income countries. All participants reported a high level of satisfaction with the workshop and a strong positive perceived short-term impact on their practice. Importantly, while this was true for both in-person and virtual attendees, in-person attendees reported a significantly higher satisfaction with the workshop (28.63 ± 3.08 vs 27.63 ± 3.93; P = .04) and perceived impact on their clinical practice (22.37 ± 3.42 vs 21.02 ± 3.45 P = .01). CONCLUSION: Hybrid simulation-based educational comprehensive cleft care workshops are overall well received by participants and have a positive perceived impact on their clinical practices. In-person attendance is associated with significantly higher satisfaction and perceived impact on practice. Considering that financial and health constraints may limit live meeting attendance, future efforts will focus on making in-person and virtual attendance more comparable.
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Labio Leporino , Fisura del Paladar , Humanos , Fisura del Paladar/terapia , Labio Leporino/terapia , Estudios Transversales , Cabeza , Satisfacción PersonalRESUMEN
Objective: Improve the quality and diversity of candidates invited for the Otolaryngology-Head and Neck Surgery residency match by reducing geographical and inter-rater bias with a novel geographic distribution algorithm. Methods: Interview applicants were divided into geographic regions and assigned to reviewers. Each reviewer selected by force-ranking a pre-determined number of applicants to invite for interviews based on the percentage of applications received for each region. Our novel geographic distribution algorithm was then applied to maintain the geographic representation and underrepresented minority status of invited applicants to match the applicant pool. Results: Analysis of previous interview selection methods demonstrated a statistically significant overrepresentation of local applicants invited for interviews. In 2022, 324 domestic applications were received for the otolaryngology match, which were divided into six geographic regions. There was no significant difference in USMLE scores between regions. The implementation of our distribution algorithm during applicant selection eliminated local overrepresentation in the invited pool of applicants and maintained the representation of underrepresented minority applicants. Following the match, reviewers indicated that implementation of the geographic distribution algorithm was simple and improved the quality and diversity of the group of interviewed applicants. Conclusion: Traditional methods of scoring and inviting otolaryngology residency applicants can be confounded by regional and inter-rater biases. Employing a geographic distribution algorithm improves the quality and diversity of invited applicants, eliminates bias, and maintains the representation of underrepresented minority applicants.
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Background: The GILLS (gastroesophageal reflux, preoperative intubation, late intervention (>14 days), low birth weight (<2500 g), and syndromic diagnosis) score is a validated predictor of success for tongue-lip adhesion (TLA) in patients with Robin sequence (RS). Objective: To evaluate the application of the GILLS score to mandibular distraction osteogenesis (MDO) for airway management in patients with RS and the associated syndromes. Methods: A retrospective chart review of 21 patients diagnosed with RS and treated with MDO surgery between the years 2006 and 2016 was performed. Success was defined by tracheostomy status outcome measures. Statistical analysis of the success was completed. Results: A GILLS score limit of ≤3 had a positive predictive value of 100%, a negative predictive value of 50%, 83% sensitivity, and 100% specificity. Conclusions: These data imply that the GILLS scoring algorithm is applicable to aiding in the selection of patients with RS for MDO, including patients with known syndromes.
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Osteogénesis por Distracción , Síndrome de Pierre Robin , Algoritmos , Animales , Branquias , Humanos , Labio/cirugía , Síndrome de Pierre Robin/complicaciones , Síndrome de Pierre Robin/cirugía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Little is known about the effects of secondhand marijuana smoke on children. We aimed to determine caregiver marijuana use prevalence and evaluate any association between secondhand marijuana smoke, childhood emergency department (ED) or urgent care (UC) visitation, and several tobacco-related illnesses: otitis media, viral respiratory infections (VRIs), and asthma exacerbations. METHODS: This study was a cross-sectional, convenience sample survey of 1500 subjects presenting to a pediatric ED. The inclusion criteria were as follows: caregivers aged 21-85 years, English- or Spanish-speaking. The exclusion criteria were as follows: children who were critically ill, medically complex, over 11 years old, or using medical marijuana. RESULTS: Of 1500 caregivers, 158 (10.5%) reported smoking marijuana and 294 (19.6%) reported smoking tobacco. Using negative-binomial regression, we estimated rates of reported ED/UC visits and specific illnesses among children with marijuana exposure and those with tobacco exposure, compared to unexposed children. Caregivers who used marijuana reported an increased rate of VRIs in their children (1.31 episodes/year) compared to caregivers with no marijuana use (1.04 episodes/year) (p = 0.02). CONCLUSIONS: Our cohort did not report any difference with ED/UC visits, otitis media episodes, or asthma exacerbations, regardless of smoke exposure. However, caregivers of children with secondhand marijuana smoke exposure reported increased VRIs compared to children with no smoke exposure. IMPACT: Approximately 10% of caregivers in our study were regular users of marijuana. Prior studies have shown that secondhand tobacco smoke exposure is associated with negative health outcomes in children, including increased ED utilization and respiratory illnesses. Prior studies have shown primary marijuana use is linked to negative health outcomes in adults and adolescents, including increased ED utilization and respiratory illnesses. Our study reveals an association between secondhand marijuana smoke exposure and increased VRIs in children. Our study did not find an association between secondhand marijuana smoke exposure and increased ED or UC visitation in children.
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Asma , Cannabis , Infecciones del Sistema Respiratorio , Contaminación por Humo de Tabaco , Adolescente , Adulto , Asma/epidemiología , Niño , Estudios Transversales , Humanos , Infecciones del Sistema Respiratorio/epidemiología , Contaminación por Humo de Tabaco/efectos adversosRESUMEN
Bleeding complications due to IHs are generally limited. Secondary abscess formation after hemorrhage has not been reported. Rapid expansion of an IH should raise concern for hemorrhage in IHs that have been an involutionary phase.
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OBJECTIVE: Velopharyngeal insufficiency (VPI) is a common speech disorder in patients with a history of cleft palate (CP) or 22q11.2 deletion syndrome. Pharyngeal flap (PF) and sphincter pharyngoplasty (SP) are 2 common surgeries to treat this disorder by decreasing unwanted nasal air emission and hypernasal resonance. Because Eustachian tube dysfunction (ETD) in patients with CP may be more frequent after surgery for VPI, we examined whether ETD was associated with either type of surgery. DESIGN: Retrospective cohort study. SETTING: Children's hospital-based tertiary referral center. PATIENTS: A total of 225 children with VPI who underwent primary PF (201) or SP (24) between 2006 and 2017. OUTCOME MEASURES: We examined differences in risk of ETD according to both surgical groups and proxies for postoperative nasal obstruction. These proxies included postoperative resonance measures and development of obstructive sleep apnea (OSA). RESULTS: Both surgical groups had similar preoperative measures, except the PF group had higher hypernasality by PSA. Postoperatively, the PF group demonstrated lower hypernasal resonance by nasometry and PSA. There were no differences between PF and SP groups with regard to ETD. Proxies for postoperative nasal obstruction also were not predictive of postoperative ETD. Degree of CP and younger age were found to be risk factors for ETD. CONCLUSION: There was no significant difference in the effects of PF and SP on ETD in this study. Neither lower hypernasality nor incidence of OSA had any impact on ETD. Degree of CP and younger age were the only significant risk factors for ETD that this study identified.
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Fisura del Paladar , Trompa Auditiva , Insuficiencia Velofaríngea , Niño , Fisura del Paladar/cirugía , Trompa Auditiva/cirugía , Humanos , Faringe/cirugía , Estudios Retrospectivos , Resultado del Tratamiento , Insuficiencia Velofaríngea/cirugíaRESUMEN
OBJECTIVE: Low-dose nonselective ß blockade is an effective treatment for problematic infantile hemangioma (PIH). Screening electrocardiograms (ECG) are performed prior to the initiation of propranolol to minimize the risk of exacerbating undiagnosed heart block. How ECG results affect subsequent propranolol usage and patient management remains unclear. We examined the value of ECG prior to propranolol therapy in a quaternary pediatric hospital. METHODS: A retrospective chart review was performed on all infants who received propranolol (2 mg/kg/day divided three times daily) to treat PIH at Arkansas Children's Hospital from Sept. 2008 to Sept. 2015. All available demographic, historical, and clinical data were obtained. ECGs and echocardiographic data were reviewed and summarized. A pediatric cardiologist read all ECGs. RESULTS: A total of 333 patients (75% female) received propranolol therapy. ECG information was available for 317 (95%). Abnormal findings were present on 44/317 (13.9%) of study ECGs. The most common abnormal finding was "voltage criteria for ventricular hypertrophy" (n = 35, 76.1%). Two patients had abnormal rhythms; one had first-degree atrioventricular (AV) block, and one had occasional premature atrial contractions. Of the 31 patients who underwent echocardiograms, 20 (35%) were abnormal. 2.9% of infants with PIH treated with propranolol required a follow-up with a cardiologist. No patient was precluded from taking propranolol due to the findings on screening ECG. CONCLUSIONS: Screening ECGs prior to propranolol therapy are abnormal in nearly 14% of patients with PIH but are unlikely to preclude therapy. In the absence of prior cardiac history, this cohort offers further evidence suggesting that screening ECGs may be of limited value in determining the safety of propranolol in otherwise healthy infants with PIH.
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Our objective was to identify the percentage of marijuana-using caregivers who have been asked about their marijuana use by their child's pediatrician. Data was collected from a cross-sectional, convenience sample survey study of 1500 caregivers presenting with their children to the Children's Hospital Colorado Pediatric Emergency Department between December 2015 and July 2017. Of the 1500 caregivers surveyed, 167 (11%) reported using marijuana. When asked if their child's pediatrician had ever inquired/counseled about caregiver marijuana use, 165 marijuana-using caregivers responded; 149 caregivers (90.3%) reported "no," 9 caregivers (5.4%) reported "yes," and 7 caregivers (4.2%) reported "unsure." We concluded that of marijuana-using caregivers, only a small percentage indicated their child's pediatrician had inquired about caregiver marijuana use. This suggests pediatricians are not engaging caregivers about marijuana use and the subsequent secondhand marijuana smoke exposure for children. The continued rise of marijuana use among parents makes this research of public health importance.
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OBJECTIVES/HYPOTHESIS: To determine whether the presence of detectable upper respiratory infections (URIs) at the time of adenoidectomy/adenotonsillectomy is associated with increased morbidity, complications, and unexpected admissions. STUDY DESIGN: Prospective double-blinded cohort. METHODS: In this prospective cohort study, nasopharyngeal swabs were obtained intraoperatively from 164 pediatric patients undergoing outpatient adenoidectomy/tonsillectomy with or without pressure equalization tubes (PETs) and were analyzed with PCR for the presence of 22 known URIs, including SARS-CoV-2. Surgeons and families were blinded to the results. At the conclusion of the study, rates of detectable infection were determined and intraoperative and postoperative events (unexpected admissions, length of PACU stay, rates of laryngospasm/bronchospasm, oxygen desaturation, bradycardia, and postoperative presentation to an emergency department) were compared between infected and uninfected patients. RESULTS: Of the 164 patients (50% male, 50% female, ages 8 mo-18 y), 136 patients (82.9%) tested positive for one or more URI at the time of surgery. Forty one patients (25.0%) tested positive for three or more URIs concurrently, and 11 (6.7%) tested positive for five or more URIs concurrently. There were no significant differences in admission rates, length of PACU stay, rates of laryngospasm/bronchospasm, oxygen desaturation, bradycardia, or postoperative presentation to an emergency department between positive and negative patients. No patients tested positive for SARS-CoV-2. CONCLUSIONS: A recent positive URI test does not confer any additional intraoperative or postoperative risk in the setting of outpatient adenoidectomy/tonsillectomy in healthy patients. There is no utility in preoperative URI testing, and delaying surgery due to a recent positive URI test is not warranted in this population. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2074-E2079, 2021.
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Adenoidectomía , Microbiología del Aire , Procedimientos Quirúrgicos Ambulatorios , Infecciones del Sistema Respiratorio/microbiología , Infección de la Herida Quirúrgica/microbiología , Tonsilectomía , Adolescente , Niño , Preescolar , Estudios de Cohortes , Método Doble Ciego , Femenino , Humanos , Lactante , Masculino , Nasofaringe/microbiología , Estudios Prospectivos , Riesgo , Factores de RiesgoRESUMEN
Background: Venous malformations (VMs) are congenital vascular malformations that grow progressively and never resolve on their own. Cutaneous VMs are difficult to treat due to risk of injury and deformation. The purpose of this study was to examine the safety and efficacy of a modified neodymium-doped yttrium aluminum garnet laser (Gentle YAG) in the management of cutaneous VMs. Methods: Retrospective chart review of patients undergoing Gentle YAG therapy for cutaneous VMs and a blind prospective evaluation of photographs, performed by 10 reviewers, before and after treatment for growth, stability, improvement, or resolution of VMs. Results: Forty-five patients (18 males and 27 females) who underwent Gentle YAG therapy for a cutaneous VM were identified. Based on photographic review, Gentle YAG therapy elicited improvement in the appearance of VMs in 72% of the patients, χ2 (1, N = 45) = 25.94, p < 0.0001, with reviewers noting complete resolution in 8.2%, significant improvement in 34.5%, some improvement in 29.3%, and no growth or improvement in 20.9% of patients. Growth of the VM was noted in 7.3% of patients. Three (6.7%) patients reported complications from the treatment, which included infection, bleeding, blister, and color change. Four patients (8.9%) reported pretreatment pain, which resolved in three (75.0%) after treatment. Conclusions: Gentle YAG therapy can provide safe and effective treatment for cutaneous VMs and should be considered in the multimodal management of VMs.
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Procedimientos Quirúrgicos Dermatologicos/métodos , Láseres de Estado Sólido/uso terapéutico , Piel/irrigación sanguínea , Malformaciones Vasculares/cirugía , Venas/anomalías , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Fotograbar , Estudios Prospectivos , Estudios Retrospectivos , Método Simple Ciego , Resultado del Tratamiento , Venas/cirugía , Adulto JovenRESUMEN
ABSTRACT: The ongoing COVID-19 outbreak has created obstacles to health care delivery on a global scale. Low- and middle-income countries (LMICs), many of which already suffered from unmet surgical and medical needs, are at great risk of suffering poor health outcomes due to health care access troubles brought on by the pandemic. Craniofacial outreach programs (CFOP)-a staple for craniofacial surgeons-have historically provided essential care to LMICs. To date, there has not been literature discussing the process of resuming CFOP mission trips. Herein, we propose a roadmap to help guide future journeys, as well as summarize practical considerations.
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Anomalías Craneofaciales/cirugía , Accesibilidad a los Servicios de Salud , Seguridad del Paciente , COVID-19 , Países en Desarrollo , Humanos , Pobreza , CirujanosRESUMEN
Caudal homeobox genes are found across animals, typically linked to two other homeobox genes in what has been called the ParaHox cluster. These genes have been proposed to pattern the anterior-posterior axis of the endoderm ancestrally, but the expression of Caudal in extant groups is varied and often occurs in other germ layers. Here we examine the role of Caudal in the embryo of the mollusc Tritia (Ilyanassa) obsoleta. ToCaudal expression is initially broad, then becomes progressively restricted and is finally only in the developing hindgut (a.k.a. intestine). Knockdown of ToCaudal using morpholino oligonucleotides specifically blocks hindgut development, indicating that despite its initially broad expression, the functional role of ToCaudal is in hindgut patterning. This is the first functional characterization of Caudal in an animal with spiralian development, which is an ancient mode of embryogenesis that arose early in bilaterian animal evolution. These results are consistent with the hypothesis that the ancestral role of the ParaHox genes was anterior-posterior patterning of the endoderm.
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Tipificación del Cuerpo/genética , Regulación del Desarrollo de la Expresión Génica , Genes Homeobox , Caracoles/embriología , Caracoles/genética , Animales , Sistema Digestivo/embriología , Embrión no Mamífero/metabolismo , Técnicas de Silenciamiento del Gen , Estratos Germinativos/embriología , Estratos Germinativos/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Familia de Multigenes , Filogenia , Caracoles/metabolismoRESUMEN
Vascular malformations are generally congenital benign lesions that have multiple variations in treatment algorithms. Surgery can be used as a single modality or as an adjunct in multimodal therapy to treat these lesions. Here we discuss surgical treatment of the major vascular malformations, including lymphatic, venous, and arteriovenous malformations. We explain some of the basic principles to resection of simple and complex lesions and adjunctive therapies. These adjunct therapies include chemotherapeutic injections, embolization, and laser therapy. Surgical resection of complex lesions should only be performed by an experienced vascular anomalies surgeon. A team approach is generally necessary to provide safe and effective treatment. While surgery for these complex lesions is an option, the most important principle to adhere to when treating any of these lesions is that the treatment should be no worse than the disease.
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Anomalías Linfáticas/cirugía , Malformaciones Vasculares/cirugía , Procedimientos Quirúrgicos Vasculares , Toma de Decisiones Clínicas , Humanos , Anomalías Linfáticas/diagnóstico por imagen , Anomalías Linfáticas/fisiopatología , Selección de Paciente , Factores de Riesgo , Resultado del Tratamiento , Malformaciones Vasculares/diagnóstico por imagen , Malformaciones Vasculares/fisiopatología , Procedimientos Quirúrgicos Vasculares/efectos adversosRESUMEN
Gastropod shell morphologies are famously diverse but generally share a common geometry, the logarithmic coil. Variations on this morphology have been modeled mathematically and computationally but the developmental biology of shell morphogenesis remains poorly understood. Here we characterize the organization and growth patterns of the shell-secreting epithelium of the larval shell of the basket whelk Tritia (also known as Ilyanassa). Despite the larval shell's relative simplicity, we find a surprisingly complex organization of the shell margin in terms of rows and zones of cells. We examined cell division patterns with EdU incorporation assays and found two growth zones within the shell margin. In the more anterior aperture growth zone, we find that inferred division angles are biased to lie parallel to the shell edge, and these divisions occur more on the margin's left side. In the more posterior mantle epithelium growth zone, inferred divisions are significantly biased to the right, relative to the anterior-posterior axis. These growth zones, and the left-right asymmetries in cleavage patterns they display, can explain the major modes of shell morphogenesis at the level of cellular behavior. In a gastropod with a different coiling geometry, Planorbella sp., we find similar shell margin organization and growth zones as Tritia, but different left-right asymmetries than we observed in the helically coiled shell of Tritia These results indicate that differential growth patterns in the mantle edge epithelium contribute to shell shape in gastropod shells and identify cellular mechanisms that may vary to generate shell diversity in evolution.
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Exoesqueleto/anatomía & histología , Exoesqueleto/crecimiento & desarrollo , División Celular/fisiología , Gastrópodos/anatomía & histología , Gastrópodos/metabolismo , Animales , Epitelio/fisiologíaRESUMEN
Classified by their most prominent vessel type, congenital vascular tumors and malformations are frequently evident neonatally. Although many are identified in the first month of life, management is often delayed due to their slow expansion. Urgent interventions may be necessary in fast-growing, obstructive, destructive, or bleeding anomalies. Treatment is based on the impact on vital structures, impending aesthetic outcome, or functional risks. Frequent and fast-growing hemangiomas and lymphatic malformations are the most commonly treated neonatally. This article reviews lesions that might require early intervention, including hemangiomas, lymphatic and venous malformations, and the rare kaposiform hemangioendothelioma.
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Hemangioma/cirugía , Terapia por Láser/métodos , Ultrasonografía Prenatal/métodos , Malformaciones Vasculares/diagnóstico por imagen , Neoplasias Vasculares/cirugía , Criocirugía/métodos , Femenino , Hemangioma/diagnóstico por imagen , Hemangioma/patología , Humanos , Recién Nacido , Angiografía por Resonancia Magnética/métodos , Masculino , Pronóstico , Medición de Riesgo , Resultado del Tratamiento , Malformaciones Vasculares/cirugía , Neoplasias Vasculares/diagnóstico por imagen , Neoplasias Vasculares/patologíaAsunto(s)
Hidrocarburos/efectos adversos , Surfactantes Pulmonares/administración & dosificación , Síndrome de Dificultad Respiratoria/inducido químicamente , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Femenino , Humanos , Lactante , Neumonía/inducido químicamente , Factores de Tiempo , TráqueaRESUMEN
OBJECTIVES/HYPOTHESIS: To delineate clinical characteristics and treatment outcomes of eosinophilic esophagitis (EoE) in the youngest of children. STUDY DESIGN: Retrospective chart review. METHODS: A 7-year retrospective chart review of children with clinicopathologic diagnosis of EoE was performed with specific analysis of patients under 5 years old. EoE was defined as the presence of symptoms of esophageal dysfunction with pathologically proven eosinophilic inflammation (≥15 eosinophils per high-power field [EOS/HPF]) unresponsive to reflux therapy. Patient parameters and clinical results were systematically reviewed. RESULTS: Of 558 children diagnosed with EoE, 127 (22.8%) were younger than 5 years old (mean age 2.5 years). This subgroup presented with reflux symptoms (90.1%), vomiting (86.2%), diarrhea (55.3%), liquid dysphagia (52.0%), and constipation (50.0%), whereas food impaction (1.6%) was rare. Liquid dysphagia was present at all ages but significantly more common in younger children (P = .0101). The most common food and environmental allergens were egg whites (39.7%), cow's milk (36.5%), peanuts (34.9%), animal dander (15.1%), and weed pollen (11.1%). Patients were managed with antireflux medication (100%), elimination diet (83.5%), and steroid medication (68.5%). After treatment, 86% of parents reported symptom improvement. Mean reduction of EOS in pos-treatment biopsy was 33.5 EOS/HPF (P < .0001), and 67 patients showed histologic resolution of EoE (56.8%, P < .0001). CONCLUSIONS: Approximately one-quarter of children with EoE present under 5 years of age with multiple esophageal symptoms, comorbidities, and allergen-sensitization profiles. These patients demonstrate substantial clinicohistologic improvement following therapy. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:798-805, 2018.
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Trastornos de Deglución/etiología , Esofagitis Eosinofílica/patología , Reflujo Gastroesofágico/etiología , Preescolar , Estreñimiento/etiología , Diarrea/etiología , Esofagitis Eosinofílica/complicaciones , Esofagitis Eosinofílica/inmunología , Esófago/patología , Femenino , Hipersensibilidad a los Alimentos/inmunología , Humanos , Masculino , Estudios Retrospectivos , Vómitos/etiologíaRESUMEN
Whether errors in protein synthesis play a role in aging has been a subject of intense debate. It has been suggested that rare mistakes in protein synthesis in young organisms may result in errors in the protein synthesis machinery, eventually leading to an increasing cascade of errors as organisms age. Studies that followed generally failed to identify a dramatic increase in translation errors with aging. However, whether translation fidelity plays a role in aging remained an open question. To address this issue, we examined the relationship between translation fidelity and maximum lifespan across 17 rodent species with diverse lifespans. To measure translation fidelity, we utilized sensitive luciferase-based reporter constructs with mutations in an amino acid residue critical to luciferase activity, wherein misincorporation of amino acids at this mutated codon re-activated the luciferase. The frequency of amino acid misincorporation at the first and second codon positions showed strong negative correlation with maximum lifespan. This correlation remained significant after phylogenetic correction, indicating that translation fidelity coevolves with longevity. These results give new life to the role of protein synthesis errors in aging: Although the error rate may not significantly change with age, the basal rate of translation errors is important in defining lifespan across mammals.
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Longevidad/genética , Mutación , Biosíntesis de Proteínas , Roedores/genética , Animales , Peso Corporal , Genes Reporteros , Código Genético , Luciferasas/genética , Luciferasas/metabolismo , Filogenia , Roedores/anatomía & histología , Roedores/clasificación , Especificidad de la EspecieRESUMEN
In some animal groups, the secondary embryonic axis is patterned by a small group of cells, often called an organizer, that signals to other cells to establish the correct pattern of cell fates. The Dpp/BMP2-4 pathway plays a central role in secondary axis patterning in many animals [1-11], but it has not been examined during early axial patterning in spiralian embryogenesis. This is a deeply conserved mode of development found in mollusks, annelids, nemerteans, entoprocts, and some marine platyhelminth groups (reviewed in [12, 13]). In the spiralian embryo of the mollusk Ilyanassa, we find that the Dpp ortholog (IoDpp) is expressed most strongly on the dorsal side, in cells of the embryonic organizer and its neighbors. Phospho-smad staining indicates that the pathway is active in all lineages during organizer signaling, but activation is strongest on the dorsal side. Knockdown of IoDpp by morpholino oligos prevents the development of all structures that require organizer signaling and ventralizes the embryo. Ectopic activation of the pathway can induce eyes and external shell, which require organizer signaling. These results indicate that Dpp/BMP2-4 signaling is a key part of the spiralian organizer and suggest similarity with other metazoan organizers. However, the fact that IoDpp/BMP2-4 is inducing, rather than repressing, the neuroectoderm is a surprising difference that may be conserved among spiralians. These results connect the spiralian organizer to this general aspect of secondary axis patterning but highlight the significant variation across animals in effects of the pathway on particular cell types and tissues.