210 research outputs found
Mutations in FKBP10 Cause Recessive Osteogenesis Imperfecta and Bruck Syndrome
Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by bone fragility and alteration in synthesis and posttranslational modification of type I collagen. Autosomal dominant OI is caused by mutations in the genes (COL1A1 or COL1A2) encoding the chains of type I collagen. Bruck syndrome is a recessive disorder featuring congenital contractures in addition to bone fragility; Bruck syndrome type 2 is caused by mutations in PLOD2 encoding collagen lysyl hydroxylase, whereas Bruck syndrome type 1 has been mapped to chromosome 17, with evidence suggesting region 17p12, but the gene has remained elusive so far. Recently, the molecular spectrum of OI has been expanded with the description of the basis of a unique posttranslational modification of type I procollagen, that is, 3-prolyl-hydroxylation. Three proteins, cartilage-associated protein (CRTAP), prolyl-3-hydroxylase-1 (P3H1, encoded by the LEPRE1 gene), and the prolyl cis-trans isomerase cyclophilin-B (PPIB), form a complex that is required for fibrillar collagen 3-prolyl-hydroxylation, and mutations in each gene have been shown to cause recessive forms of OI. Since then, an additional putative collagen chaperone complex, composed of FKBP10 (also known as FKBP65) and SERPINH1 (also known as HSP47), also has been shown to be mutated in recessive OI. Here we describe five families with OI-like bone fragility in association with congenital contractures who all had FKBP10 mutations. Therefore, we conclude that FKBP10 mutations are a cause of recessive osteogenesis imperfecta and Bruck syndrome, possibly Bruck syndrome Type 1 since the location on chromosome 17 has not been definitely localized. © 2011 American Society for Bone and Mineral Research
Young Adult Brain Capital: A New Opportunity for Dementia Prevention
The potential for future prevention of Alzheimer's disease and related dementias (ADRD) through healthy lifestyle change is spurring a positive brain health movement. However, most ADRD research continues to focus on mid- and later life. We lack evidence regarding risk exposure and protective factors in young adulthood, i.e., 18-39 years. Brain capital is an emerging framework that represents the combination of education, knowledge, skills, and optimal brain health that people accumulate over their lives. Building on this framework, we present a new model that focuses on optimizing brain health in young adulthood; namely, young adult brain capital. Increasing focus on younger populations is critical for developing citizens who are emotionally intelligent, resilient and can anticipate and cope with rapid changes in the world. By understanding the values that are key drivers and motivators for young adults, we can empower the next generation to become active agents in optimizing their brain health and reducing their risk for future ADRD
Horizontal gene transfer dynamics and distribution of fitness effects during microbial in silico evolution
<p>Abstract</p> <p>Background</p> <p>Horizontal gene transfer (HGT) is a process that facilitates the transfer of genetic material between organisms that are not directly related, and thus can affect both the rate of evolution and emergence of traits. Recent phylogenetic studies reveal HGT events are likely ubiquitous in the Tree of Life. However, our knowledge of HGT's role in evolution and biological organization is very limited, mainly due to the lack of ancestral evolutionary signatures and the difficulty to observe complex evolutionary dynamics in a laboratory setting. Here, we utilize a multi-scale microbial evolution model to comprehensively study the effect of HGT on the evolution of complex traits and organization of gene regulatory networks.</p> <p>Results</p> <p>Large-scale simulations reveal a distinct signature of the Distribution of Fitness Effect (DFE) for HGT events: during evolution, while mutation fitness effects become more negative and neutral, HGT events result in a balanced effect distribution. In either case, lethal events are significantly decreased during evolution (33.0% to 3.2%), a clear indication of mutational robustness. Interestingly, evolution was accelerated when populations were exposed to correlated environments of increasing complexity, especially in the presence of HGT, a phenomenon that warrants further investigation. High HGT rates were found to be disruptive, while the average transferred fragment size was linked to functional module size in the underlying biological network. Network analysis reveals that HGT results in larger regulatory networks, but with the same sparsity level as those evolved in its absence. Observed phenotypic variability and co-existing solutions were traced to individual gain/loss of function events, while subsequent re-wiring after fragment integration was necessary for complex traits to emerge.</p
The Role of Bile in the Regulation of Exocrine Pancreatic Secretion
As early as 1926 Mellanby (1) was able to show that introduction of bile into the duodenum of anesthetized cats produces a copious flow of pancreatic juice. In conscious dogs, Ivy & Lueth (2) reported, bile is only a weak stimulant of pancreatic secretion. Diversion of bile from the duodenum, however, did not influence pancreatic volume secretion stimulated by a meal (3,4). Moreover, Thomas & Crider (5) observed that bile not only failed to stimulate the secretion of pancreatic juice but also abolished the pancreatic response to intraduodenally administered peptone or soap
International Consensus Recommendations for the Treatment of Pediatric NMDAR Antibody Encephalitis.
OBJECTIVE: To create an international consensus treatment recommendation for pediatric NMDA receptor antibody encephalitis (NMDARE). METHODS: After selection of a panel of 27 experts with representation from all continents, a 2-step Delphi method was adopted to develop consensus on relevant treatment regimens and statements, along with key definitions in pediatric NMDARE (disease severity, failure to improve, and relapse). Finally, an online face-to-face meeting was held to reach consensus (defined as ≥75% agreement). RESULTS: Corticosteroids are recommended in all children with NMDARE (pulsed IV preferred), with additional IV immunoglobulin or plasma exchange in severe patients. Prolonged first-line immunotherapy can be offered for up to 3-12 months (oral corticosteroids or monthly IV corticosteroids/immunoglobulin), dependent on disease severity. Second-line treatments are recommended for cases refractory to first-line therapies (rituximab preferred over cyclophosphamide) and should be considered about 2 weeks after first-line initiation. Further immunotherapies for refractory disease 1-3 months after second-line initiation include another second-line treatment (such as cyclophosphamide) and escalation to tocilizumab. Maintenance immune suppression beyond 6 months (such as rituximab redosing or mycophenolate mofetil) is generally not required, except for patients with a more severe course or prolonged impairments and hospitalization. For patients with relapsing disease, second-line and prolonged maintenance therapy should be considered. The treatment of NMDARE following herpes simplex encephalitis should be similar to idiopathic NMDARE. Broad guidance is provided for the total treatment duration (first line, second line, and maintenance), which is dictated by the severity and clinical course (i.e., median 3, 9 and 18 months in the best, average, and worst responders, respectively). Recommendations on the timing of oncologic searches are provided. CONCLUSION: These international consensus recommendations for the management of pediatric NMDARE aim to standardize the treatment and provide practical guidance for clinicians, rather than absolute rules. A similar recommendation could be applicable to adult patients
Pervasive Adaptive Protein Evolution Apparent in Diversity Patterns around Amino Acid Substitutions in Drosophila simulans
In Drosophila, multiple lines of evidence converge in suggesting that beneficial substitutions to the genome may be common. All suffer from confounding factors, however, such that the interpretation of the evidence—in particular, conclusions about the rate and strength of beneficial substitutions—remains tentative. Here, we use genome-wide polymorphism data in D. simulans and sequenced genomes of its close relatives to construct a readily interpretable characterization of the effects of positive selection: the shape of average neutral diversity around amino acid substitutions. As expected under recurrent selective sweeps, we find a trough in diversity levels around amino acid but not around synonymous substitutions, a distinctive pattern that is not expected under alternative models. This characterization is richer than previous approaches, which relied on limited summaries of the data (e.g., the slope of a scatter plot), and relates to underlying selection parameters in a straightforward way, allowing us to make more reliable inferences about the prevalence and strength of adaptation. Specifically, we develop a coalescent-based model for the shape of the entire curve and use it to infer adaptive parameters by maximum likelihood. Our inference suggests that ∼13% of amino acid substitutions cause selective sweeps. Interestingly, it reveals two classes of beneficial fixations: a minority (approximately 3%) that appears to have had large selective effects and accounts for most of the reduction in diversity, and the remaining 10%, which seem to have had very weak selective effects. These estimates therefore help to reconcile the apparent conflict among previously published estimates of the strength of selection. More generally, our findings provide unequivocal evidence for strongly beneficial substitutions in Drosophila and illustrate how the rapidly accumulating genome-wide data can be leveraged to address enduring questions about the genetic basis of adaptation
The Brain Health Diplomat's Toolkit: supporting brain health diplomacy leaders in Latin America and the Caribbean.
Maintaining and improving brain health, one of the most critical global challenges of this century, necessitates innovative, interdisciplinary, and collaborative strategies to address the growing challenges in Latin America and the Caribbean. This paper introduces Brain Health Diplomacy (BHD) as a pioneering approach to bridge disciplinary and geographic boundaries and mobilize resources to promote equitable brain health outcomes in the region. Our framework provides a toolkit for emerging brain health leaders, equipping them with essential concepts and practical resources to apply in their professional work and collaborations. By providing case studies, we highlight the importance of culturally sensitive, region-specific interventions to address unique needs of vulnerable populations. By encouraging dialogue, ideation, and cross-sector discussions, we aspire to develop new research, policy, and programmatic avenues. The novel BHD approach has the potential to revolutionize brain health across the region and beyond, ultimately contributing to a more equitable global cognitive health landscape
Index finger movement imitation by human neonates: motivation, learning, and left-hand preference
Imitation of a fine motor movement, index finger protrusion, was examined in 39 neonates using an ethologically based objective coding system. Results confirmed that imitation of finger movements exists, and infants demonstrated "learning" as imitation developed through an incomplete imitation stage. Neonatal imitation was more frequently left-handed, an early sign of laterality in motivation to be investigated further. The existence of index finger imitation in human neonates indicates that volitional control of individuated finger movements develops much earlier than previously thought. The differential increase of index finger protrusion movements during the imitation periods suggests that this behavior is not an automatic response triggered by general arousal but instead is a true indicator of purposeful neonatal imitation
Exploring the tensions of being and becoming a medical educator
BackgroundPrevious studies have identified tensions medical faculty encounter in their roles but not specifically those with a qualification in medical education. It is likely that those with postgraduate qualifications may face additional tensions (i.e., internal or external conflicts or concerns) from differentiation by others, greater responsibilities and translational work against the status quo. This study explores the complex and multi-faceted tensions of educators with qualifications in medical education at various stages in their career.MethodsThe data described were collected in 2013–14 as part of a larger, three-phase mixed-methods research study employing a constructivist grounded theory analytic approach to understand identity formation among medical educators. The over-arching theoretical framework for the study was Communities of Practice. Thirty-six educators who had undertaken or were undertaking a postgraduate qualification in medical education took part in semi-structured interviews.ResultsParticipants expressed multiple tensions associated with both becoming and being a healthcare educator. Educational roles had to be juggled with clinical work, challenging their work-life balance. Medical education was regarded as having lower prestige, and therefore pay, than other healthcare career tracks. Medical education is a vast speciality, making it difficult as a generalist to keep up-to-date in all its areas. Interestingly, the graduates with extensive experience in education reported no fears, rather asserting that the qualification gave them job variety.ConclusionThis is the first detailed study exploring the tensions of educators with postgraduate qualifications in medical education. It complements and extends the findings of the previous studies by identifying tensions common as well as specific to active students and graduates. These tensions may lead to detachment, cynicism and a weak sense of identity among healthcare educators. Postgraduate programmes in medical education can help their students identify these tensions in becoming and develop coping strategies. Separate career routes, specific job descriptions and academic workload models for medical educators are recommended to further the professionalisation of medical education
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