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OBJECTIVE: This study aimed to provide contemporary data regarding provider perceptions of appropriate care for resuscitation and stabilization of periviable infants and institutional resources available to providers. STUDY DESIGN: A Qualtrics survey was emailed to 672 practicing neonatologists in the United States by use of public databases. Participants were asked about appropriate delivery room care for infants born at 22 to 26 weeks gestational age, factors affecting decision-making, and resources utilized regarding resuscitation. Descriptive statistics were used to analyze the dataset. RESULTS: In total, 180 responses were received, and 173 responses analyzed. Regarding preferred course of care based on gestational age, the proportion of respondents endorsing full resuscitation decreased with decreasing gestational age (25 weeks = 99%, 24 = 64%, 23 = 16%, and 22 = 4%). Deference to parental wishes correspondingly increased with decreasing gestational age (25 weeks = 1%, 24 = 35%, 23 = 82%, and 22 = 46%). Provision of comfort care was only endorsed at 22 to 23 weeks (23 weeks = 2%, 22 = 50%). Factors most impacting decision-making at 22 weeks gestational age included: outcomes based on population data (79%), parental wishes (65%), and quality of life measures (63%). Intubation with a 2.5-mm endotracheal tube (84%), surfactant administration in the delivery room (77%), and vascular access (69%) were the most supported therapies for initial stabilization. Availability of institutional resources varied; the most limited were obstetric support for cesarean delivery at the limit of viability (37%), 2.0-mm endotracheal tube (45%), small baby protocols (46%), and a consulting palliative care teams (54%). CONCLUSION: There appears to be discordance in provider attitudes surrounding preferred actions at 23 and 22 weeks. Provider attitudes regarding decision-making at the limit of viability and identified resource limitations are nonuniform. Between-hospital variations in outcomes for periviable infants may be partly attributable to lack of provider consensus and nonuniform resource availability across institutions. KEY POINTS: · Within the past decade, there has been a shift in the gray zone from 23-24 to 22-23 weeks gestation.. · Attitudes around resuscitation of infants are nonuniform despite perceived standardized approaches.. · Institutional variability in resources may contribute to variation in outcomes of periviable infants..
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Calidad de Vida , Resucitación , Actitud del Personal de Salud , Femenino , Edad Gestacional , Humanos , Lactante , Neonatólogos , EmbarazoRESUMEN
INTRODUCTION: There is the need for a device that can be used to accurately position components during total knee arthroplasty (TKA) with minimal impact on procedure time, workflow and cost. This study aimed to investigate the accuracy and time efficiency of a novel, accelerometer-based navigation system (ABN). METHODS: This prospective, single surgeon study of patients undergoing TKA for osteoarthritis over a 5 year period involved a total of 138 patients: 110 using the ABN system and 28 without. The ABN system consists of two coupled inertial pods that are secured to resection guides, providing a body-fixed 3D coordinate system for limb segments. Post-operative coronal alignment was measured from standardised long-leg AP radiographs. Deviation of the femur and tibia from the neutral coronal mechanical axis was recorded. Intra-observer repeatability was performed on three independent blinded data sets. The BMI and the surgical time (skin to skin) were recorded for all patients. RESULTS: The mean BMI was 34 in the ABN group and 33 in the control group (p = 0.92). The skin-to-skin time was also similar between the groups; 105 min in the navigation group and 100 min in the control group (p = 0.297). The use of navigation resulted in significantly fewer outliers as defined by < 3º deviation from the target angle. 3 of 110 navigated patients recorded an AP femur angle of more than 3º from the target of 90º, where 5 of 28 control patients fell outside of the ± 3º window (p = 0.009, Fig. 1). CONCLUSION: The use of the ABN system significantly improved accuracy of implant position and alignment without increasing surgical time.
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Acelerometría/métodos , Artroplastia de Reemplazo de Rodilla/métodos , Cirugía Asistida por Computador/métodos , Fémur/cirugía , Humanos , Rodilla/cirugía , Estudios Prospectivos , Tibia/cirugíaRESUMEN
BACKGROUND: The ePartogram is a tablet-based application developed to improve care for women in labor by addressing documented challenges in partograph use. The application is designed to provide real-time decision support, improve data entry, and increase access to information for appropriate labor management. This study's primary objective was to evaluate the feasibility and acceptability of ePartogram use in resource-constrained clinical settings. METHODS: The ePartogram was introduced at three facilities in Zanzibar, Tanzania. Following 3 days of training, skilled birth attendants (SBAs) were observed for 2 weeks using the ePartogram to monitor laboring women. During each observed shift, data collectors used a structured observation form to document SBA comfort, confidence, and ability to use the ePartogram. Results were analyzed by shift. Short interviews, conducted with SBAs (n = 82) after each of their first five ePartogram-monitored labors, detected differences over time. After the observation period, in-depth interviews were conducted (n = 15). A thematic analysis of interview transcripts was completed. RESULTS: Observations of 23 SBAs using the ePartogram to monitor 103 women over 84 shifts showed that the majority of SBAs (87-91%) completed each of four fundamental ePartogram tasks-registering a client, entering first and subsequent measurements, and navigating between screens-with ease or increasing ease on their first shift; this increased to 100% by the fifth shift. Nearly all SBAs (93%) demonstrated confidence and all SBAs demonstrated comfort in using the ePartogram by the fifth shift. SBAs expressed positive impressions of the ePartogram and found it efficient and easy to use, beginning with first client use. SBAs noted the helpfulness of auditory reminders (indicating that measurements were due) and visual alerts (signaling abnormal measurements). SBAs expressed confidence in their ability to interpret and act on these reminders and alerts. CONCLUSIONS: It is feasible and acceptable for SBAs to use the ePartogram to support labor management and care. With structured training and support during initial use, SBAs quickly became competent and confident in ePartogram use. Qualitative findings revealed that SBAs felt the ePartogram improved timeliness of care and supported decision-making. These findings point to the ePartogram's potential to improve quality of care in resource-constrained labor and delivery settings.
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Técnicas de Apoyo para la Decisión , Monitoreo Fetal/métodos , Trabajo de Parto/psicología , Partería/métodos , Aceptación de la Atención de Salud/psicología , Adulto , Parto Obstétrico/instrumentación , Parto Obstétrico/métodos , Estudios de Factibilidad , Femenino , Humanos , Servicios de Salud Materna , Embarazo , Investigación Cualitativa , TanzaníaRESUMEN
BACKGROUND: Patients who were incarcerated were disproportionately affected by COVID-19 compared with the general public. Furthermore, the impact of multidisciplinary rehabilitation assessments and interventions on the outcomes of patients admitted to the hospital with COVID-19 is limited. OBJECTIVE: We aimed to compare the functional outcomes of oral intake, mobility, and activity between inmates and noninmates diagnosed with COVID-19 and examine the relationships among these functional measures and discharge destination. METHODS: A retrospective analysis was performed on patients admitted to the hospital for COVID-19 at a large academic medical center. Scores on functional measures including the Functional Oral Intake Scale and Activity Measure for Postacute Care (AM-PAC) were collected and compared between inmates and noninmates. Binary logistic regression models were used to evaluate the odds of whether patients were discharged to the same place they were admitted from and whether patients were being discharged with a total oral diet with no restrictions. Independent variables were considered significant if the 95% CIs of the odds ratios (ORs) did not include 1.0. RESULTS: A total of 83 patients (inmates: n=38; noninmates: n=45) were included in the final analysis. There were no differences between inmates and noninmates in the initial (P=.39) and final Functional Oral Intake Scale scores (P=.35) or in the initial (P=.06 and P=.46), final (P=.43 and P=.79), or change scores (P=.97 and P=.45) on the AM-PAC mobility and activity subscales, respectively. When examining separate regression models using AM-PAC mobility or AM-PAC activity scores as independent variables, greater age upon admission decreased the odds (OR 0.922, 95% CI 0.875-0.972 and OR 0.918, 95% CI 0.871-0.968) of patients being discharged with a total oral diet with no restrictions. The following factors increased the odds of patients being discharged to the same place they were admitted from: being an inmate (OR 5.285, 95% CI 1.334-20.931 and OR 6.083, 95% CI 1.548-23.912), "Other" race (OR 7.596, 95% CI 1.203-47.968 and OR 8.515, 95% CI 1.311-55.291), and female sex (OR 4.671, 95% CI 1.086-20.092 and OR 4.977, 95% CI 1.146-21.615). CONCLUSIONS: The results of this study provide an opportunity to learn how functional measures may be used to better understand discharge outcomes in both inmate and noninmate patients admitted to the hospital with COVID-19 during the initial period of the pandemic.
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Neonatal opiate withdrawal syndrome (NOWS), previously known as neonatal abstinence syndrome (NAS), is a growing public health concern as opiate misuse and opioid-related overdoses, from both prescription and illicit sources, continue to rise in the USA. As more than 90% of females abusing opioids are of child-bearing age, the failure to adequately address the opioid epidemic continues to negatively impact the next generations. Accurate and timely identification of infants at risk for withdrawal from in-utero exposure is critical to ensure high-quality perinatal and neonatal care. Beginning with an evaluation of current best practices and performing a literature review, we identify the challenges to current screening processes and how these limitations limit the ability to provide appropriate care to infants at the risk of withdrawal. We first describe the limitations of the available assays for the detection of opioid and opioid metabolites across different biological sources from both the mother and the infant. We then present a discussion surrounding factors that contribute to maternal willingness to disclose use. Particularly, in light of the limitations of biological screening, any barrier to maternal disclosure further complicates effective care delivery. Barriers to disclosure include legal ramifications and state policies, provider and societal behaviors and biases, and maternal factors. Moving forward, universal prenatal screening surveys coupled with enhanced outreach and education to providers centering on the limitations of both patient report and biological sampling, as well as comprehensive and supportive services for women of reproductive age with substance use disorders, are needed to both enhance detection for NOWS and improve long-term maternal-child health.
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Síndrome de Abstinencia Neonatal , Alcaloides Opiáceos , Trastornos Relacionados con Opioides , Complicaciones del Embarazo , Analgésicos Opioides/uso terapéutico , Niño , Femenino , Humanos , Lactante , Recién Nacido , Síndrome de Abstinencia Neonatal/diagnóstico , Síndrome de Abstinencia Neonatal/epidemiología , Alcaloides Opiáceos/uso terapéutico , Tratamiento de Sustitución de Opiáceos , Trastornos Relacionados con Opioides/diagnóstico , Trastornos Relacionados con Opioides/tratamiento farmacológico , Trastornos Relacionados con Opioides/epidemiología , Atención Perinatal , Embarazo , Complicaciones del Embarazo/diagnóstico , Complicaciones del Embarazo/tratamiento farmacológico , Complicaciones del Embarazo/epidemiologíaRESUMEN
A diverse soil microbial community is involved in nitrogen cycling, and these microbes can be affected by land management practices and weed invasion. We surveyed 20 woodlands with a history of livestock grazing, with livestock recently excluded from 10 sites. We investigated whether soil nutrients were lower when grazing was excluded and higher when exotic grasses dominated the understory. Second, using quantitative real-time PCR, we investigated whether microbial nitrogen functional gene (NFG) abundance was altered with soil nutrient enrichment, livestock exclusion, and exotic grass invasion. The target genes were chiA (decomposition-ammonification), nifH (nitrogen fixation), nirK and narG (denitrification), and bacterial amoA (nitrification). Woodland soils were enriched in phosphorus and nitrogen compared to reference condition sites, but soil nutrients were not lower following livestock exclusion. Total nitrogen and nifH were negatively correlated in grazed woodlands, suggesting that aboveground herbivory reduces the capacity for belowground nitrogen fixation. Woodlands dominated by exotic grasses had higher levels of nitrate, narG, and nirK than those dominated by native grasses. We hypothesize that the increase in potential for denitrification was due to increases in soil nitrate, rather than changes in plant composition. Overall, soil physicochemistry explained more variation in NFG abundance than livestock presence or plant invasion, particularly for chiA and bacterial amoA, with significant relationships between the abundance of all five NFGs and total nitrogen or nitrate. All woodlands investigated had a history of anthropogenic disturbance and nutrification, and soil nutrient levels and the abundance of NFGs are likely to be related to long-term land management practices.
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Biodiversidad , Perfilación de la Expresión Génica , Redes y Vías Metabólicas/genética , Metagenoma , Nitrógeno/metabolismo , Microbiología del Suelo , Suelo/análisis , Animales , Animales Domésticos , Biomasa , Ecosistema , Genes , Fósforo/análisis , PlantasRESUMEN
OBJECTIVES: The incidence of neonatal opioid withdrawal syndrome (NOWS) has increased fivefold over the last 10 years. Standardized NOWS care protocols have revealed many improved patient outcomes. Our objective for this study is to describe results of a clinical practice survey of NOWS management practices designed to inform future clinical studies in the diagnosis and management of NOWS. METHODS: A cross-sectional survey was administered to medical unit directors at 32 Institutional Development Award States Pediatric Clinical Trial Network and 22 Neonatal Research Network sites in the fall of 2017. Results are presented as both the number and percentage of positive responses. Ninety-five percent Wilson confidence intervals (CIs) were generated around estimates, and χ2 and Fisher's exact tests were used to compare the association between unit type and reporting of each protocol. RESULTS: Sixty-two responses representing 54 medical centers were received. Most participating NICU and non-ICU sites reported protocols for NOWS management, including NOWS scoring (98% NICU; 86% non-ICU), pharmacologic treatment (92% NICU; 64% non-ICU), and nonpharmacologic care (79% NICU; 79% non-ICU). Standardized protocols for pharmacologic care and weaning were reported more frequently in the NICU (92% [95% CI: 80%-97%] and 94% [95% CI: 83%-98%], respectively) compared with non-ICU settings (64% [95% CI: 39%-84%] for both) (P < .05 for both comparisons). Most medical centers reported morphine as first-line therapy (82%; 95% CI: 69%-90%) and level 3 and level 4 NICUs as the location of pharmacologic treatment (83%; 95% CI: 71%-91%). CONCLUSIONS: Observed variations in care between NICUs and non-ICUs revealed opportunities for targeted interventions in training and standardized care plans in non-ICU sites.
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Protocolos Clínicos , Encuestas de Atención de la Salud/métodos , Síndrome de Abstinencia Neonatal/terapia , Analgésicos Opioides/uso terapéutico , Estudios Transversales , Encuestas de Atención de la Salud/estadística & datos numéricos , Humanos , Recién Nacido , Síndrome de Abstinencia Neonatal/tratamiento farmacológicoRESUMEN
22q11 deletion syndrome (22q11DS) is caused by an interstitial chromosomal microdeletion that encompasses about 40 genes. It is the most common of the microdeletion syndromes. The clinical phenotype, which is complex and variable, includes specific congenital defects of the cardiovascular system, craniofacies, and immune system. In early childhood, patients manifest cognitive impairment, behavioral disorders, and delays in motor development and language acquisition. Adult patients have a high risk for developing serious psychiatric disorders, especially schizophrenia, schizoaffective disorder, and bipolar disorder. The great majority of patients have an identical or near identical chromosomal deletion, and genotype-phenotype correlations have not been established. Indeed, little progress was made toward resolving the complex clinical phenotype until the deletion was successfully modeled in the mouse. In recent years, through a variety of mouse mutants that carry multigene and single gene mutations, we have learned that mutation in a single gene, Tbx1, is responsible for most of the congenital defects seen in the mouse models and in patients. We now face a greater challenge as we attempt to use the mouse to address the pathogenesis of the behavioral and psychiatric disorders associated with 22q11DS. Significant progress has already been made, and recent studies in the mouse suggest that several genes from the deleted region affect behavior and might contribute to disease burden in patients.
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Síndrome de DiGeorge/genética , Modelos Animales de Enfermedad , Proteínas de Dominio T Box/genética , Animales , Conducta Animal , Síndrome de DiGeorge/psicología , Humanos , RatonesRESUMEN
BACKGROUND: As part of needs assessment processes, our Faculty of Medicine (FOM) continuing professional development office investigated the differences between physicians who do and those who do not frequently participate in planned group learning to gain insight into their interest in new forms of continuing professional development (CPD). METHOD: We sent a 19 item questionnaire to 485 randomly selected physicians of the 1050 family physicians in Eastern Ontario. The questionnaire examined present participation and satisfaction with CPD activities and perceptions regarding the potential impact of those; and appetite for new opportunities to meet their learning needs. RESULTS: Of the 151 (31%) physicians responding, 61% reported attending at least one FOM group learning program in the past 18 months (attenders) and 39% had not (non-attenders). Non-attenders indicated less satisfaction (p = 0.04) with present opportunities and requested development in newer approaches such as support for self-learning, on-line opportunities, and simulation. CONCLUSIONS: Although there are high levels of satisfaction with the present CPD system that predominantly offers large group learning options, a substantial number of physicians expressed interest in accessing new options such as personal study and on-line resources.
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The intracellular pathogen, Legionella pneumophila, relies on numerous secreted effector proteins to manipulate host endomembrane trafficking events during pathogenesis, thereby preventing fusion of the bacteria-laden phagosome with host endolysosomal compartments, and thus escaping degradation. Upon expression in the surrogate eukaryotic model Saccharomyces cerevisiae, we find that the L. pneumophila LegC7/YlfA effector protein disrupts the delivery of both biosynthetic and endocytic cargo to the yeast vacuole. We demonstrate that the effects of LegC7 are specific to the endosome:vacuole delivery pathways; LegC7 expression does not disrupt other known vacuole-directed pathways. Deletions of the ESCRT-0 complex member, VPS27, provide resistance to the LegC7 toxicity, providing a possible target for LegC7 function in vivo. Furthermore, a single amino acid substitution in LegC7 abrogates both its toxicity and ability to alter endosomal traffic in vivo, thereby identifying a critical functional domain. LegC7 likely inhibits endosomal trafficking during L. pneumophila pathogenesis to prevent entry of the phagosome into the endosomal maturation pathway and eventual fusion with the lysosome.
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Proteínas Bacterianas/metabolismo , Endocitosis , Endosomas/metabolismo , Legionella pneumophila , Saccharomyces cerevisiae/citología , Proteínas Bacterianas/genética , Complejos de Clasificación Endosomal Requeridos para el Transporte/deficiencia , Complejos de Clasificación Endosomal Requeridos para el Transporte/genética , Eliminación de Gen , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Vacuolas/metabolismoRESUMEN
Salmonella enterica serovar Enteritidis is a common cause of salmonellosis in people in the UK. This study aimed to assess the degree of genetic diversity among animal and human isolates from UK, Wales and northern Ireland. A total of 250 isolates from humans (n = 59) and animals or their environment (n = 191), belonging to the most common phage-types, were fingerprinted by a combination of PFGE, PS ribotyping and plasmid profiling. The different techniques identified different degrees of polymorphism (PS ribotyping (52 types) > PFGE (22 types) > plasmid profiling (17 types)). A prevalent genomic clone, as well as a variety of less frequent clones are present for each of the phage-types. In most cases, the prevalent clones appeared within isolates from several animal species and from several geographical locations. The percentage of sporadic clones found in animal and human populations were very similar. There was not clear evidence of a higher degree of diversity for human or animal isolates. Some clones were found to be present in both human and animal.
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Salmonella enteritidis/genética , Animales , Tipificación de Bacteriófagos/métodos , Dermatoglifia del ADN , ADN Bacteriano/química , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Microbiología de Alimentos , Variación Genética , Humanos , Plásmidos , Ribotipificación , Infecciones por Salmonella/microbiología , Salmonella enteritidis/clasificación , Salmonella enteritidis/aislamiento & purificación , Reino UnidoRESUMEN
Chrysanthemoides monilifera ssp rotundata (L) T Norl (Bitou bush) is a serious environmental weed along the southeast coast of Australia. The herbicide glyphosate is commonly used to control C monilifera on the New South Wales coastline, but there have been few studies examining the effects of this herbicide on invertebrate communities in the field, especially on sand dunes. Control and impact sites were selected in coastal hind dunes heavily infested with C monilifera, and the impact sites were sprayed with a 1:100 v/v dilution of glyphosate-isopropyl 360 g AE litre(-1) SL (Roundup Biactive). Leaf litter invertebrates were sampled before spraying and after spraying by collecting fixed areas of leaf litter in both the control and impact sites. Samples were sorted for particular invertebrates involved in leaf litter decomposition and some of their predators. This study did not identify any significant direct or indirect effects on leaf litter invertebrate abundance or community composition in the four months following herbicide application. The litter invertebrate assemblages were highly variable on a small spatial scale, with abiotic factors more strongly regulating leaf litter invertebrate numbers than glyphosate application. These results conflict with previous studies, indicating that the detrimental indirect effects herbicide application has on non-target litter invertebrates may depend upon the application rate, the vegetation community and structure and post-spray weather.
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Asteraceae , Glicina/análogos & derivados , Glicina/toxicidad , Herbicidas/toxicidad , Invertebrados/efectos de los fármacos , Animales , Ambiente , Dinámica Poblacional , GlifosatoRESUMEN
UNLABELLED: Although heme iron is an important form of dietary iron, its intestinal absorption mechanism remains elusive. Our previous study revealed that (-)-epigallocatechin-3-gallate (EGCG) and grape seed extract (GSE) markedly inhibited intestinal heme iron absorption by reducing the basolateral iron export in Caco-2 cells. The aim of this study was to examine whether small amounts of EGCG, GSE, and green tea extract (GT) could inhibit heme iron absorption, and to test whether the inhibitory action of polyphenols could be offset by ascorbic acid. A heme-55Fe absorption study was conducted by adding various concentrations of EGCG, GSE, and GT to Caco-2 cells in the absence and presence of ascorbic acid. Polyphenolic compounds significantly inhibited heme-55Fe absorption in a dose-dependent manner. The addition of ascorbic acid did not modulate the inhibitory effect of dietary polyphenols on heme iron absorption when the cells were treated with polyphenols at a concentration of 46 mg/L. However, ascorbic acid was able to offset or reverse the inhibitory effects of polyphenolic compounds when lower concentrations of polyphenols were added (≤ 4.6 mg/L). Ascorbic acid modulated the heme iron absorption without changing the apical heme uptake, the expression of the proteins involved in heme metabolism and basolateral iron transport, and heme oxygenase activity, indicating that ascorbic acid may enhance heme iron absorption by modulating the intracellular distribution of 55Fe. These results imply that the regular consumption of dietary ascorbic acid can easily counteract the inhibitory effects of low concentrations of dietary polyphenols on heme iron absorption but cannot counteract the inhibitory actions of high concentrations of polyphenols. PRACTICAL APPLICATION: Bioactive dietary polyphenols inhibit heme iron absorption in a dose-dependent manner. The small amounts of polyphenolic compounds present in foods are capable of reducing heme iron transport across the intestinal enterocyte. However, the inhibitory effects of dietary polyphenolic compounds on heme iron absorption can be offset by ascorbic acid and can possibly be avoided by decreasing the consumption of polyphenols while simultaneously taking ascorbic acid.
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Dieta , Absorción Intestinal/efectos de los fármacos , Intestinos/citología , Hierro de la Dieta/sangre , Extractos Vegetales/farmacología , Polifenoles/farmacología , Animales , Antioxidantes/farmacología , Ácido Ascórbico/metabolismo , Transporte Biológico/efectos de los fármacos , Células CACO-2 , Catequina/análogos & derivados , Catequina/farmacología , Relación Dosis-Respuesta a Droga , Enterocitos/efectos de los fármacos , Enterocitos/metabolismo , Extracto de Semillas de Uva/farmacología , Hemo/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Intestinos/efectos de los fármacos , Hierro de la Dieta/antagonistas & inhibidores , Ratones , Té/químicaRESUMEN
About 35% of patients with 22q11 deletion syndrome (22q11DS), which includes DiGeorge and velocardiofacial syndromes, develops psychiatric disorders, mainly schizophrenia and bipolar disorder. We previously reported that mice carrying a multigene deletion (Df1) that models 22q11DS have reduced prepulse inhibition (PPI), a behavioral abnormality and schizophrenia endophenotype. Impaired PPI is associated with several psychiatric disorders, including those that occur in 22q11DS, and recently, reduced PPI was reported in children with 22q11DS. Here, we have mapped PPI deficits in a panel of mouse mutants that carry deletions that partially overlap with Df1 and have defined a PPI critical region encompassing four genes. We then used single-gene mutants to identify the causative genes. We show that PPI deficits in Df1/+ mice are caused by haploinsufficiency of two genes, Tbx1 and Gnb1l. Mutation of either gene is sufficient to cause reduced PPI. Tbx1 is a transcription factor, the mutation of which is sufficient to cause most of the physical features of 22q11DS, but the gene had not been previously associated with the behavioral/psychiatric phenotype. A likely role for Tbx1 haploinsufficiency in psychiatric disease is further suggested by the identification of a family in which the phenotypic features of 22q11DS, including psychiatric disorders, segregate with an inactivating mutation of TBX1. One family member has Asperger syndrome, an autistic spectrum disorder that is associated with reduced PPI. Thus, Tbx1 and Gnb1l are strong candidates for psychiatric disease in 22q11DS patients and candidate susceptibility genes for psychiatric disease in the wider population.
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Síndrome de DiGeorge/genética , Trastornos Mentales/genética , Proteínas de Dominio T Box , Adulto , Animales , Conducta Animal/fisiología , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Niño , Análisis Mutacional de ADN , Femenino , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Mutación , Linaje , Fenotipo , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/metabolismoRESUMEN
Bardet-Biedl syndrome (BBS) is a rare oligogenic disorder exhibiting both clinical and genetic heterogeneity. Although the BBS phenotype is variable both between and within families, the syndrome is characterized by the hallmarks of developmental and learning difficulties, post-axial polydactylia, obesity, hypogenitalism, renal abnormalities, retinal dystrophy, and several less frequently observed features. Eleven genes mutated in BBS patients have been identified, and more are expected to exist, since about 20-30% of all families cannot be explained by the known loci. To investigate the etiopathogenesis of BBS, we created a mouse null for one of the murine homologues, Bbs4, to assess the contribution of one gene to the pleiotropic murine Bbs phenotype. Bbs4 null mice, although initially runted compared to their littermates, ultimately become obese in a gender-dependent manner, females earlier and with more severity than males. Blood chemistry tests indicated abnormal lipid profiles, signs of liver dysfunction, and elevated insulin and leptin levels reminiscent of metabolic syndrome. As in patients with BBS, we found age-dependent retinal dystrophy. Behavioral assessment revealed that mutant mice displayed more anxiety-related responses and reduced social dominance. We noted the rare occurrence of birth defects, including neural tube defects and hydrometrocolpos, in the null mice. Evaluations of these null mice have uncovered phenotypic features with age-dependent penetrance and variable expressivity, partially recapitulating the human BBS phenotype.
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Síndrome de Bardet-Biedl/genética , Proteínas Asociadas a Microtúbulos/genética , Penetrancia , Envejecimiento , Animales , Ansiedad/genética , Ansiedad/patología , Síndrome de Bardet-Biedl/sangre , Síndrome de Bardet-Biedl/patología , Femenino , Insulina/sangre , Intrones , Leptina/sangre , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Mutagénesis Insercional , Obesidad/genética , Obesidad/patología , Fenotipo , Retina/patología , Predominio SocialRESUMEN
The 22q11 deletion syndrome (22q11DS; DiGeorge/velo-cardio-facial syndrome) primarily affects the structures comprising the pharyngeal arches and pouches resulting in arch artery, cardiac, parathyroid, thymus, palatal and craniofacial defects. Tbx1 haploinsufficiency is thought to account for the main structural anomalies observed in the 22q11DS. The Df1 deleted mouse provides a model for 22q11DS, the deletion reflecting Tbx1 haploinsufficiency in the context of the deletion of 21 adjacent genes. We examined the expression of genes in Df1 embryos at embryonic day (E) 10.5, a stage when the arch-artery phenotype is fully penetrant. Our aims were threefold, with our primary aim to identify differentially regulated genes. Second, we asked whether any of the genes hemizygous in Df1 were dosage compensated to wild type levels, and third we investigated whether genes immediately adjacent to the deletion were dysregulated secondary to a position effect. Utilisation of oligonulceotide arrays allowed us to achieve our aims with 9 out of 12 Df1 deleted genes passing the stringent statistical filtering applied. Several genes involved in vasculogenesis and cardiogenesis were validated by real time quantitative PCR (RTQPCR), including Connexin 45, a gene required for normal vascular development, and Dnajb9 a gene implicated in microvascular differentiation. There was no evidence of any dosage compensation of deleted genes, suggesting this phenomenon is rare, and no dysregulation of genes mapping immediately adjacent to the deletion was detected. However Crkl, another gene implicated in the 22q11DS phenotype, was found to be downregulated by microarray and RTQPCR.
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Deleción Cromosómica , Cromosomas Humanos Par 22 , Síndrome de DiGeorge/genética , Modelos Animales de Enfermedad , Animales , Análisis por Conglomerados , Síndrome de DiGeorge/embriología , Femenino , Dosificación de Gen , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Análisis por Micromatrices , Reacción en Cadena de la Polimerasa , Proteínas de Dominio T Box/genéticaRESUMEN
22q11-deletion (DiGeorge/velocardiofacial) syndrome (22q11DS) is modeled by mutation of murine transcription factor Tbx1. As part of efforts to identify transcriptional targets of Tbx1, we analyzed the transcriptome of the pharyngeal region of Df1/+;Tbx1+/- embryos at 9.5 days of embryonic development using two independent microarray platforms. In this model, embryos are null for Tbx1, with hemizygosity of genes in cis with Tbx1 on one chromosome providing a positive control for array sensitivity. Reduced mRNA levels of genes deleted from Df1 were detected on both platforms. Expression level filtering and statistical analysis identified several genes that were consistently differentially expressed between mutant and wild type embryos. Real-time quantitative PCR and in situ hybridization validated diminished expression of Pax9 and Gcm2, genes known to be required for normal thymus and parathyroid gland morphogenesis, whereas Pax1, Hoxa3, Eya1, and Foxn1, which are similarly required, were not down-regulated. Gbx2, a gene required for normal arch artery development, was down-regulated specifically in the pharyngeal endoderm and the posterior part of pharyngeal arch 1, and is a potential point of cross talk between the Tbx1 and Fgf8 controlled pathways. These experiments highlight which genes and pathways potentially affected by lack of Tbx1, and whose role may be explored further by testing for epistasis using mouse mutants.
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Región Branquial/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Ratones/embriología , Ratones/genética , Proteínas de Dominio T Box/genética , Animales , Hibridación in Situ , Ratones Mutantes , Análisis por Micromatrices , Factor de Transcripción PAX9 , Factores de Transcripción Paired Box , Reacción en Cadena de la Polimerasa , Proteínas de Dominio T Box/metabolismoRESUMEN
During embryonic life, the initially paired pharyngeal arch arteries (PAAs) follow a precisely orchestrated program of persistence and regression that leads to the formation of the mature aortic arch and great vessels. When this program fails, specific cardiovascular defects arise that may be life threatening or mild, according to the identity of the affected artery. Fourth PAA-derived cardiovascular defects occur commonly in DiGeorge syndrome and velocardiofacial syndrome (22q11DS), and in Tbx1(+/-) mice that model the 22q11DS cardiovascular phenotype. Tbx1 is expressed in pharyngeal mesoderm, endoderm and ectoderm, and, in addition, we show that it is expressed in precursors of the endothelial cells that line the PAAs, thus expanding the number of tissues in which Tbx1 is potentially required for fourth PAA development. In this study, we have used cell fate mapping and tissue-specific gene deletion, driven by six different Cre lines, to explore Tbx1 gene-dosage requirements in the embryonic pharynx for fourth PAA development. Through this approach, we have resolved the spatial requirements for Tbx1 in this process, and we show pharyngeal epithelia to be a critical tissue. We also thereby demonstrate conclusively that the role of Tbx1 in fourth PAA development is cell non-autonomous.
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Arterias/crecimiento & desarrollo , Región Branquial/irrigación sanguínea , Epitelio/fisiología , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/fisiología , Animales , Aorta Torácica , Embrión de Mamíferos , Epitelio/química , Eliminación de Gen , Dosificación de Gen , Ratones , Ratones Endogámicos , Faringe/embriologíaRESUMEN
TBX1 is thought to be a critical gene in the pathogenesis of del22q11/DiGeorge syndrome (DGS). Morphological abnormalities of the external ear and hearing impairment (conductive or sensorineural) affect the majority of patients. Here we show that homozygous mutation of the mouse homolog Tbx1 is associated with severe inner ear defects that prevent the formation of the cochlea and of the vestibulum. Consistent with phenotypic abnormalities, Tbx1 is expressed early in otocyst development in the otic epithelium and in the periotic mesenchyme. Tbx1 loss-of-function blocks inner ear development at early otocyst stage and after neurogenesis. Analysis of chimeras suggests that Tbx1 function is required in the otic epithelium cell autonomously, but abnormalities of the periotic mesenchyme indicate that the pathogenesis of the inner ear phenotype is complex. We propose a model where Tbx1 is required for expansion of a subpopulation of otic epithelial cells, which is required to form the vestibular and auditory organs. Our data suggest that Tbx1 deletion in del22q11 patients may cause not only external and middle ear defects but also sensorineural and vestibular phenotypes observed in these patients.
Asunto(s)
Oído Interno/embriología , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/metabolismo , Animales , Supervivencia Celular , Quimera , Síndrome de DiGeorge/genética , Oído Interno/patología , Células Epiteliales/citología , Femenino , Pérdida Auditiva Sensorineural/genética , Pérdida Auditiva Sensorineural/patología , Ratones , Modelos Biológicos , Morfogénesis , Mutación , FenotipoRESUMEN
TBX1 is the major candidate gene for DiGeorge syndrome (DGS). Mouse studies have shown that the Tbx1 gene is haploinsufficient, as expected for a DGS candidate gene, and that it is required for the development of pharyngeal arches and pouches, as predicted by the DGS clinical phenotype. However, a detailed analysis of the cardiovascular phenotype associated with Tbx1 mutations has not been reported. Here we show that Tbx1 deficiency causes a number of distinct vascular and heart defects, suggesting multiple roles in cardiovascular development - specifically formation and growth of the pharyngeal arch arteries, growth and septation of the outflow tract of the heart, interventricular septation, and conal alignment. Comparison of phenotype and gene expression using a Tbx1-lacZ reporter allele supports a cell-autonomous function in the growth of the pharyngeal apparatus, and a cell non-autonomous function in the growth and early remodeling of the pharyngeal arch arteries. Our data do not support a direct role of neural crest cells in the pathogenesis of the Tbx1 mutant phenotype; however, these cells, and the cranial nerves, are misdirected. We hypothesize that this is due to the lack of a guidance role from the pouch endoderm, which is missing in these mutants.