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424 result(s) for "Williamson, Rebecca"
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Preschool physics: Using the invisible property of weight in causal reasoning tasks
Causal reasoning is an important aspect of scientific thinking. Even young human children can use causal reasoning to explain observations, make predictions, and design actions to bring about specific outcomes in the physical world. Weight is an interesting type of cause because it is an invisible property. Here, we tested preschool children with causal problem-solving tasks that assessed their understanding of weight. In an experimental setting, 2- to 5-year-old children completed three different tasks in which they had to use weight to produce physical effects-an object displacement task, a balance-scale task, and a tower-building task. The results showed that the children's understanding of how to use object weight to produce specific object-to-object causal outcomes improved as a function of age, with 4- and 5-year-olds showing above-chance performance on all three tasks. The younger children's performance was more variable. The pattern of results provides theoretical insights into which aspects of weight processing are particularly difficult for preschool children and why they find it difficult.
Chimpanzees play the ultimatum game
Is the sense of fairness uniquely human? Human reactions to reward division are often studied by means of the ultimatum game, in which both partners need to agree on a distribution for both to receive rewards. Humans typically offer generous portions of the reward to their partner, a tendency our close primate relatives have thus far failed to show in experiments. Here we tested chimpanzees (Pan troglodytes) and human children on a modified ultimatum game. One individual chose between two tokens that, with their partner’s cooperation, could be exchanged for rewards. One token offered equal rewards to both players, whereas the other token favored the chooser. Both apes and children responded like humans typically do. If their partner’s cooperation was required, they split the rewards equally. However, with passive partners—a situation akin to the so-called dictator game—they preferred the selfish option. Thus, humans and chimpanzees show similar preferences regarding reward division, suggesting a long evolutionary history to the human sense of fairness.
Phosphatidylinositol-3-phosphate regulates sorting and processing of amyloid precursor protein through the endosomal system
Defects in endosomal sorting have been implicated in Alzheimer’s disease. Endosomal traffic is largely controlled by phosphatidylinositol-3-phosphate, a phosphoinositide synthesized primarily by lipid kinase Vps34. Here we show that phosphatidylinositol-3-phosphate is selectively deficient in brain tissue from humans with Alzheimer’s disease and Alzheimer’s disease mouse models. Silencing Vps34 causes an enlargement of neuronal endosomes, enhances the amyloidogenic processing of amyloid precursor protein in these organelles and reduces amyloid precursor protein sorting to intraluminal vesicles. This trafficking phenotype is recapitulated by silencing components of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, including the phosphatidylinositol-3-phosphate effector Hrs and Tsg101. Amyloid precursor protein is ubiquitinated, and interfering with this process by targeted mutagenesis alters sorting of amyloid precursor protein to the intraluminal vesicles of endosomes and enhances amyloid-beta peptide generation. In addition to establishing phosphatidylinositol-3-phosphate deficiency as a contributing factor in Alzheimer’s disease, these results clarify the mechanisms of amyloid precursor protein trafficking through the endosomal system in normal and pathological states. Endosomal sorting is regulated by phosphatidylinositol-3-phosphate and anomalies in this process are implicated in Alzheimer’s disease. Here the authors show that deficiency of phosphatidylinositol-3-phosphate in vitro enhances the pathological trafficking and processing of amyloid precursor protein.
Association of Biochemical B12 Deficiency With Metformin Therapy and Vitamin B12 Supplements: The National Health and Nutrition Examination Survey, 1999–2006
OBJECTIVE: To describe the prevalence of biochemical B12 deficiency in adults with type 2 diabetes taking metformin compared with those not taking metformin and those without diabetes, and explore whether this relationship is modified by vitamin B12 supplements. RESEARCH DESIGN AND METHODS: Analysis of data on U.S. adults ≥50 years of age with (n = 1,621) or without type 2 diabetes (n = 6,867) from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Type 2 diabetes was defined as clinical diagnosis after age 30 without initiation of insulin therapy within 1 year. Those with diabetes were classified according to their current metformin use. Biochemical B12 deficiency was defined as serum B12 concentrations ≤148 pmol/L and borderline deficiency was defined as >148 to ≤221 pmol/L. RESULTS: Biochemical B12 deficiency was present in 5.8% of those with diabetes using metformin compared with 2.4% of those not using metformin (P = 0.0026) and 3.3% of those without diabetes (P = 0.0002). Among those with diabetes, metformin use was associated with biochemical B12 deficiency (adjusted odds ratio 2.92; 95% CI 1.26–6.78). Consumption of any supplement containing B12 was not associated with a reduction in the prevalence of biochemical B12 deficiency among those with diabetes, whereas consumption of any supplement containing B12 was associated with a two-thirds reduction among those without diabetes. CONCLUSIONS: Metformin therapy is associated with a higher prevalence of biochemical B12 deficiency. The amount of B12 recommended by the Institute of Medicine (IOM) (2.4 μg/day) and the amount available in general multivitamins (6 μg) may not be enough to correct this deficiency among those with diabetes.
Blood BDNF concentrations reflect brain-tissue BDNF levels across species
Brain-derived neurotrophic factor (BDNF) is involved in synaptic plasticity, neuronal differentiation and survival of neurons. Observations of decreased serum BDNF levels in patients with neuropsychiatric disorders have highlighted the potential of BDNF as a biomarker, but so far there have been no studies directly comparing blood BDNF levels to brain BDNF levels in different species. We examined blood, serum, plasma and brain-tissue BDNF levels in three different mammalian species: rat, pig, and mouse, using an ELISA method. As a control, we included an analysis of blood and brain tissue from conditional BDNF knockout mice and their wild-type littermates. Whereas BDNF could readily be measured in rat blood, plasma and brain tissue, it was undetectable in mouse blood. In pigs, whole-blood levels of BDNF could not be measured with a commercially available ELISA kit, but pig plasma BDNF levels (mean 994±186 pg/ml) were comparable to previously reported values in humans. We demonstrated positive correlations between whole-blood BDNF levels and hippocampal BDNF levels in rats (r2=0.44, p=0.025) and between plasma BDNF and hippocampal BDNF in pigs (r2=0.41, p=0.025). Moreover, we found a significant positive correlation between frontal cortex and hippocampal BDNF levels in mice (r2=0.81, p=0.0139). Our data support the view that measures of blood and plasma BDNF levels reflect brain-tissue BDNF levels.
Self-reported late effect symptom clusters among young pediatric cancer survivors
PurposeMost survivors of childhood cancer experience subsequent chronic conditions but little is known about concurrent symptoms. This study seeks to identify late effect symptom clusters among young pediatric cancer survivors.MethodsSurvivors ≥ 18 or parents of survivors < 18 years enrolled in an institutional cohort study indicated (yes/no) if they experienced certain symptoms after treatment. The sample was randomly divided in half for exploratory factor analyses to identify symptom clusters followed by confirmatory factor analyses. Symptoms with ≥ 10% prevalence were included. Cluster structure generalizability across subgroups was examined using congruence coefficients.ResultsThe sample included 579 survivors (74% non-Hispanic white, 45% leukemia, 12.8 ± 4.5 years at survey, 5.9 ± 3.5 years since therapy). Respondents averaged three symptoms. Three clusters were identified: (1) gastrointestinal: abdominal pain, diarrhea, constipation, nausea, vomiting (Cronbach’s α = 0.74); (2) psychological: depression, anxiety, memory problems, anger management problems, sleep problems (α = 0.71); and (3) neurologic: problems walking, numbness/tingling, fatigue, back pain, chronic pain, weakness/inability to move legs (α = 0.71). Confirmatory factor analysis confirmed the three-cluster structure (standardized root mean square residual: 0.09; parsimonious goodness of fit: 0.96; Bentler-Bonett normed fit index: 0.95). The gastrointestinal and psychological clusters were generalizable across most subgroups while the neurologic cluster varied across age and race/ethnicity subgroups.ConclusionThree distinct late effect symptom clusters were identified in young childhood cancer survivors with gastrointestinal and psychological clusters remaining relatively stable across subgroups. Future studies should focus on the characteristics of patients who experience these symptoms, especially those with high symptom burden, and the synergistic impact on quality of life.
Cardiac recovery via extended cell-free delivery of extracellular vesicles secreted by cardiomyocytes derived from induced pluripotent stem cells
The ability of extracellular vesicles (EVs) to regulate a broad range of cellular processes has recently been exploited for the treatment of diseases. For example, EVs secreted by therapeutic cells injected into infarcted hearts can induce recovery through the delivery of cell-specific microRNAs. However, retention of the EVs and the therapeutic effects are short-lived. Here, we show that an engineered hydrogel patch capable of slowly releasing EVs secreted from cardiomyocytes (CMs) derived from induced pluripotent stem cells reduced arrhythmic burden, promoted ejection-fraction recovery, decreased CM apoptosis 24 h after infarction, and reduced infarct size and cell hypertrophy 4 weeks post-infarction when implanted onto infarcted rat hearts. We also show that EVs are enriched with cardiac-specific microRNAs known to modulate CM-specific processes. The extended delivery of EVs secreted from induced-pluripotent-stem-cell-derived CMs into the heart may help us to treat heart injury and to understand heart recovery. A hydrogel patch for the sustained delivery of extracellular vesicles from cardiomyocytes derived from induced pluripotent stem cells improves tissue regeneration in infarcted rat hearts.
User-centered design and enhancement of an electronic personal health record to support survivors of pediatric cancers
Purpose The objective of this article is to demonstrate how user-centered design theory and methods can be employed to develop and iteratively improve technologies to support survivors of childhood cancer. Methods Focus groups and structured interviews with young adult survivors of pediatric cancer ( N = 3), parents ( N = 11), and healthcare providers ( N = 14) were conducted to understand their needs as potential users and the contexts in which they would use an electronic personal health record (PHR) for survivors, Cancer SurvivorLink TM ( https://cancersurvivorlink.org/ ). Usability evaluations were conducted to assess the functionality of the PHR using think aloud protocol with survivors/parents ( N = 4) and focus groups with providers ( N = 12). Results Major themes identified through the needs assessment guided design of the PHR, including (1) education about the lifelong healthcare needs of pediatric cancer survivors (“Learn”), (2) secure electronic storage for healthcare documents to direct long-term follow-up care (“Store”), and (3) communication functionality to allow sharing of health documents with healthcare providers (“Share”). Usability evaluations identified challenges with the PHR design, which informed site enhancements to improve PHR usefulness and ease of use including a registration wizard and healthcare provider directory. Conclusions User-centered design methods informed iterative enhancements to an untethered, patient-controlled PHR to address usability barriers and meet the self-identified needs of survivors of childhood cancer and their providers.
Multivitamin Use and Serum Vitamin B12 Concentrations in Older-Adult Metformin Users in REGARDS, 2003-2007
Metformin, an insulin-sensitizing drug, is a first line treatment for type 2 diabetes. Long-term use of metformin has been associated with subsequent reductions in vitamin B12 concentrations. The objective of our study was to determine whether metformin use is associated with lower serum vitamin B12 concentrations in older adults, and whether concurrent use of multivitamins modifies this association. We examined 2,510 participants aged 50 years and over, participating in the national population-based Reasons for Geographic And Racial Differences in Stroke (REGARDS) Study. Multivariable linear and logistic regression models were used to assess associations between multivitamin use and serum vitamin B12 concentrations. We estimated adjusted odds ratios (aOR)s and confidence intervals (CI)s. Results were stratified by three metformin/diabetes sub-groups: 1) participants with diabetes who were metformin users; 2) participants with diabetes who were not metformin users; and 3) participants without diabetes. We found that diabetic metformin users had significantly lower geometric mean serum B12 concentrations (409 pmol/L) than the group with diabetes not taking metformin (485 pmol/L; P<0.01), and the group without diabetes (445 pmol/L; P = 0.02). The geometric mean serum B12 concentrations were greater for multivitamin users (509 pmol/L) compared to those who did not use multivitamins (376 pmol/L; p<0.01). Among the participants with diabetes who were on metformin therapy, multivitamin use was associated with geometric mean serum vitamin B12 concentrations that were 50% (or 161 pmol/L) higher, compared to those not using multivitamins. Among metformin users, multivitamin use was associated with lower prevalence of combined low and borderline vitamin B12 concentrations (aOR = 0.14; 95% CI = 0.04, 0.54) compared to those not using multivitamins. In conclusion, metformin use was associated with lower geometric mean serum vitamin B12 concentrations among diabetic older adults compared to their counterparts. Concurrent multivitamin use may potentially protect against low or borderline vitamin B12 concentrations in long-term metformin users. Additional research is needed to further examine this association as low or borderline vitamin B12 concentrations can be preventable, or treatable if detected at an early stage, in long-term metformin users.
Just culture and restorative just culture in healthcare settings: a scoping review of interventions, activities, factors and outcomes
Background Just culture and, more recently, restorative just culture interventions are increasingly recognised as nonpunitive approaches to the reporting of incidents in which healthcare professionals trust that they will receive fair treatment and support. However, despite this recognition, evidence concerning the range of interventions, implementation strategies and factors for successful outcomes supported by systematic approaches remains limited. This review sought to address this gap. Methods We searched PubMed, HBE, CINAHL, PsycINFO, Scopus, Embase and grey literature from January 2000 to December 2024. We included peer-reviewed studies or quality improvement reports of any design and used an iterative, inductive approach to thematically categorise the data supplemented with descriptive statistics. Results We analysed 36 interventions across six thematic categories, which were a mix of just culture or restorative just culture interventions or existing safety interventions used to operationalise these approaches. Barriers and enablers to implementation included system improvements and accountability, a safe and supportive culture, leadership support, engagement and participation, organisational influences and external influences. Seven outcomes were identified: knowledge and confidence, communication and engagement in incident reporting, leadership engagement and support, shift towards a just, learning and safety culture, continuous improvement in processes, impact on patient safety outcomes and organisational benefits. A challenge was found in identifying the specific activities and factors contributing to the success of the interventions. Conclusions The interventions identified in this review are reflective of just culture and restorative just culture as a growing area in terms of quality and safety and incident management practices. The results suggest a number of preexisting safety interventions that can be used to operationalise these approaches, with restorative culture adding a further step of addressing the harm to the healthcare professional, crossing the boundaries of traditional patient safety functions to include Human Resources, Organisational Development and even Union functions. This review progresses the study of just culture and restorative just culture from a traditional quality improvement approach to implementation science. However, further work is needed to refine definitions to capture the extent and progress of preexisting work in this field and to develop implementation methodologies that identify relationships between interventions, barriers, enablers, outcomes and systematic methods for implementation.