2,662 research outputs found
Morphogenesis: Pharyngeal Arch Development in Ambystoma tigrinum
This study examines pharyngeal arch (PA) development in the eastern tiger salamander (Ambystoma tigrinum) during transformation. The PA is a series of six arches that give structure to the gills and is involved in feeding and moving water across the pharyngeal and branchial chambers. Proper remodeling of the PA during transformation is essential to ensure proper respiratory functioning and feeding in terrestrial salamanders. Salamander carcasses were obtained from salamanders that died before, during, or after transformation to a terrestrial state. The carcasses were cleared and stained with alcian blue (cartilage identification) and alizarin red (bone identification) to evaluate PA remodeling during transformation. The majority of salamanders exhibited abnormal PA remodeling. Based on current findings, we hypothesize that the abnormal ossification may be in part due to a changed morphogenesis process.https://openriver.winona.edu/urc2019/1115/thumbnail.jp
The MicroRNA, miRâ18a, Regulates NeuroD and Photoreceptor Differentiation in the Retina of Zebrafish
During embryonic retinal development, six types of retinal neurons are generated from multipotent progenitors in a strict spatiotemporal pattern. This pattern requires cell cycle exit (i.e. neurogenesis) and differentiation to be precisely regulated in a lineageâspecific manner. In zebrafish, the bHLH transcription factor NeuroD governs photoreceptor genesis through Notch signaling but also governs photoreceptor differentiation though distinct mechanisms that are currently unknown. Also unknown are the mechanisms that regulate NeuroD and the spatiotemporal pattern of photoreceptor development. Members of the miRâ17â92 microRNA cluster regulate CNS neurogenesis, and a member of this cluster, miRâ18a, is predicted to target neuroD mRNA. The purpose of this study was to determine if, in the developing zebrafish retina, miRâ18a regulates NeuroD and if it plays a role in photoreceptor development. Quantitative RTâPCR showed that, of the three miRâ18 family members (miRâ18a, b, and c), miRâ18a expression most closely parallels neuroD expression. Morpholino oligonucleotides and CRISPR/Cas9 gene editing were used for miRâ18a lossâofâfunction (LOF) and both resulted in larvae with more mature photoreceptors at 70 hpf without affecting cell proliferation. Western blot showed that miRâ18a LOF increases NeuroD protein levels and in vitro dual luciferase assay showed that miRâ18a directly interacts with the 3âČ UTR of neuroD. Finally, tgif1 mutants have increased miRâ18a expression, less NeuroD protein and fewer mature photoreceptors, and the photoreceptor deficiency is rescued by miRâ18a knockdown. Together, these results show that, independent of neurogenesis, miRâ18a regulates the timing of photoreceptor differentiation and indicate that this occurs through postâtranscriptional regulation of NeuroD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147840/1/dneu22666.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147840/2/dneu22666_am.pd
Controlling Schools: How School Resource Officersâ Roles Map Onto Schoolsâ Behavior Management Strategies
School resource officer (SRO) behavior varies across schools, but little is known about what shapes their behavior. Social ecological theories state that features of communities shapes individual behavior, including police officers. This may similarly apply to SROs. This study uses the 2015 to 2016 School Survey on Crime and Safety to test the extent to which three aspects of a schoolâs context related to behavior management (i.e., security measures, disciplinary environment, and restorative practices) shape SROsâ involvement in three roles: law enforcement, teacher, and mentor. Using a generalized structural equation model to examine the relationships between school context and SRO roles, consistent with ecological theories, we find that school context shapes SRO roles. Implications and future research are further discussed
Bayesian random threshold estimation in a Cox proportional hazards cure model
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102705/1/sim5964.pd
Extinction of an instrumental response: a cognitive behavioral assay in Fmr1 knockout mice
Fragile X (FX) is the most common genetic cause of intellectual disability and autism. Previous studies have shown that partial inhibition of metabotropic glutamate receptor signaling is sufficient to correct behavioral phenotypes in a mouse model of FX, including audiogenic seizures, open-field hyperactivity and social behavior. These phenotypes model well the epilepsy (15%), hyperactivity (20%) and autism (30%) that are comorbid with FX in human patients. Identifying reliable and robust mouse phenotypes to model cognitive impairments is critical considering the 90% comorbidity of FX and intellectual disability. Recent work characterized a five-choice visuospatial discrimination assay testing cognitive flexibility, in which FX model mice show impairments associated with decreases in synaptic proteins in prefrontal cortex (PFC). In this study, we sought to determine whether instrumental extinction, another process requiring PFC, is altered in FX model mice, and whether downregulation of metabotropic glutamate receptor signaling pathways is sufficient to correct both visuospatial discrimination and extinction phenotypes. We report that instrumental extinction is consistently exaggerated in FX model mice. However, neither the extinction phenotype nor the visuospatial discrimination phenotype is corrected by approaches targeting metabotropic glutamate receptor signaling. This work describes a novel behavioral extinction assay to model impaired cognition in mouse models of neurodevelopmental disorders, provides evidence that extinction is exaggerated in the FX mouse model and suggests possible limitations of metabotropic glutamate receptor-based pharmacotherapy.FRAXA Research FoundationAutism Science FoundationNational Institute of Mental Health (U.S.) (Training Grant 2T32MH074249)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant 5RO1HD046903
Awareness of moderate-to-vigorous physical activity: can information on guidelines prevent overestimation?
Background: Mass-media campaigns such as Change4Life use messaging to promote physical activity guidelines. Raising knowledge of MVPA guidelines within UK adults is a main goal of current mass media campaigns aimed at increasing engagement in MVPA. As this may help to inform accurate perceptions of adults' own MVPA level it is an important area of investigation. Subjective norms, health status and normal walking intensity may also influence adult's awareness of their own MVPA behaviour. The aim of this study was to examine the hypothesis that greater knowledge of MVPA guidelines, supportive subjective norms, lower self-reported health status and intensity of typical walking pace are associated with accurate awareness of MVPA engagement within a sample of UK adults. Methods: A cross-sectional study of UK adults was conducted. UK adults who subscribed to the National Academic Mailing List Service (JISCMail) were sent an invitation to complete an online survey. 1,724 UK adults completed the online survey which included items on minutes spent in MVPA, awareness of MVPA using constructs highlighted by the precaution adoption process model, subjective norms, knowledge of guidelines, health status and demographics. Results: The sample was 70% female, 57% aged under 45, 93% White and 69% in full-time employment. 62% reported their health to be above average, while 62% demonstrated accurate awareness of their own physical activity level, only 18% correctly reported the MVPA guidelines and 51% reported high subjective norms towards MVPA. Logistic regression analyses identified high subjective norms (OR = 1.84, CI: 1.29, 2.63, p = .001), average or below average health status (OR = .71, CI: .53 .97, p = .001), and a self-reported regular walking pace of moderate-to-vigorous (OR = 1.31, CI: 1.05, 1.63, p = .02) to be associated with accurate MVPA awareness. Knowledge of MVPA guidelines was not associated with MVPA awareness. Conclusions: Mass media campaigns, such as Change4Life, inform the general public of MVPA guidelines. Campaign messages may be more influential targeting subjective norms instead of knowledge of guidelines, thereby raising awareness of personal MVPA behaviour amongst inactive adults and increasing motivation to engage in more MVPA
Antipsychotic Polypharmacy-Related Cardiovascular Morbidity and Mortality: A Comprehensive Review
Schizophrenia is a psychotic disorder that exists at the more extreme end of a spectrum of diseases, and significantly affects daily functioning. Cardiovascular adverse effects of antipsychotic medications are well known, and include changes in blood pressure and arrhythmias. Sudden cardiac death is the leading cause of death worldwide, and antipsychotic medications are associated with numerous cardiac side effects. A possible link exists between antipsychotic medications and sudden cardiac death. Common prescribing patterns that may influence cardiovascular events include the use of multiple antipsychotics and/or additional drugs commonly prescribed to patients on antipsychotics. The results of this review reflect an association between antipsychotic drugs and increased risk of ventricular arrhythmias and sudden cardiac death by iatrogenic prolongation of the QTc interval. QTc prolongation and sudden cardiac death exist in patients taking antipsychotic monotherapy. The risk increases for the concomitant use of specific drugs that prolong the QTc interval, such as opioids, antibiotics, and illicit drugs. However, evidence suggests that QTc intervals may not adequately predict sudden cardiac death. In considering the findings of this narrative review, we conclude that it is unclear whether there is a precise association between antipsychotic polypharmacy and sudden cardiac death with QTc interval changes. The present narrative review warrants further research on this important potential association
Sixteen years of Collaborative Learning through Active Sense-making in Physics (CLASP) at UC Davis
This paper describes our large reformed introductory physics course at UC
Davis, which bioscience students have been taking since 1996. The central
feature of this course is a focus on sense-making by the students during the
five hours per week discussion/labs in which the students take part in
activities emphasizing peer-peer discussions, argumentation, and presentations
of ideas. The course differs in many fundamental ways from traditionally taught
introductory physics courses. After discussing the unique features of CLASP and
its implementation at UC Davis, various student outcome measures are presented
showing increased performance by students who took the CLASP course compared to
students who took a traditionally taught introductory physics course. Measures
we use include upper-division GPAs, MCAT scores, FCI gains, and MPEX-II scores.Comment: Also submitted to American Journal of Physic
Complications of Open Approaches to the Skull Base in the Endoscopic Era
Objective It is important to characterize the developing complication profile of the open approach as it becomes reserved for more complex disease during the endoscopic era. Our objective was to characterize complication rates of current open skull base surgery
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