Searching for Answers When Girls Don\u27t Perform Well: Evaluating Classroom Discourse and Microculture in a Sixth Grade Science Classroom

This action research project examines the role classroom culture and discourse can play on student learning, with a focus on female students. A sixth grade science classroom was evaluated through analysis of two videotaped astronomy lessons. The classroom environment utilized qualitative methods to examine teacher and student interactions, student and student interactions, and classroom environment. The research project began in response to a previous research project which found that after completing an astronomy unit male students not only out preformed female students, but female students lost gains in several area. Findings suggested that there may be a connection between the classroom discourse and microculture and the girls’ low performance

The association of posttraumatic stress disorder and quality of life during the first year after acute coronary syndrome

Acute coronary syndrome [ACS, including unstable angina (UA) or myocardial infarction (MI)] events can be psychologically traumatic experiences for patients given their unpredictable, sudden onset and life-threatening nature [1]. Although posttraumatic stress disorder (PTSD) is commonly associated with index events of war or assault, PTSD is also associated with life-threatening illness and in particular ACS with approximately 12% of patients developing PTSD [1] and [2]. PTSD due to ACS has a multitude of consequences, including increased risk of ACS recurrence and mortality [3] and [4] in addition to PTSD itself being a debilitating psychiatric condition. Sufferers of PTSD are burdened by symptoms that include re-experiencing the traumatic event via intrusive thoughts, flashbacks, or nightmares; avoiding reminders of the index event; persistent negative alterations in cognition and mood; or physiologic hyperarousal. As such, ACS-induced PTSD is likely associated with substantial detriment in quality of life (QOL). However, few studies have measured this association, and no study has investigated it among a general ACS population or longitudinally. Rather, prior studies were composed of ACS patients only in intensive care units (ICUs) or among armed-services veterans [5], [6] and [7] or are notable for limitations such as cross-sectional designs [5] and [7]

Anomalously Diffusing and Persistently Migrating Cells in 2D and 3D Culture Environments

Appropriately chosen descriptive models of cell migration in biomaterials will allow researchers to characterize and ultimately predict the movement of cells in engineered systems for a variety of applications in tissue engineering. The persistent random walk (PRW) model accurately describes cell migration on two-dimensional (2D) substrates. However, this model inherently cannot describe subdiffusive cell movement, i.e. migration paths in which the root mean square displacement increases more slowly than the square root of the time interval. Subdiffusivity is a common characteristic of cells moving in confined environments, such as three-dimensional (3D) porous scaffolds, hydrogel networks, and in vivo tissues. We demonstrate that a generalized anomalous diffusion (AD) model, which uses a simple power law to relate the mean square displacement (MSD) to time, more accurately captures individual cell migration paths across a range of engineered 2D and 3D environments than does the more commonly used PRW model. We used the AD model parameters to distinguish cell movement profiles on substrates with different chemokinetic factors, geometries (2D vs 3D), substrate adhesivities, and compliances. Although the two models performed with equal precision for superdiffusive cells, we suggest a simple AD model, in lieu of PRW, to describe cell trajectories in populations with a significant subdiffusive fraction, such as cells in confined, 3D environments

Integrin α6 and EGFR Signaling Converge at Mechanosensitive Calpain 2

Cells sense and respond to mechanical cues from the extracellular matrix (ECM) via integrins. ECM stiffness is known to enhance integrin clustering and response to epidermal growth factor (EGF), but we lack information on when or if these mechanosensitive growth factor receptors and integrins converge intracellularly. Towards closing this knowledge gap, we combined a biomaterial platform with transcriptomics, molecular biology, and functional assays to link integrin-mediated mechanosensing and epidermal growth factor receptor (EGFR) signaling. We found that high integrin α6 expression controlled breast cancer cell adhesion and motility on soft, laminin-coated substrates, and this mimicked the response of cells to EGF stimulation. The mechanisms that drove both mechanosensitive cell adhesion and motility converged on calpain 2, an intracellular protease important for talin cleavage and focal adhesion turnover. EGF stimulation enhanced adhesion and motility on soft substrates, but required integrin α6 and calpain 2 signaling. In sum, we identified a new role for integrin α6 mechanosensing in breast cancer, wherein cell adhesion to laminin on soft substrates mimicked EGF stimulation. We identified calpain 2, downstream of both integrin α6 engagement and EGFR phosphorylation, as a common intracellular signaling node, and implicate integrin α6 and calpain 2 as potential targets to inhibit the migration of cancer cells in stiff tumor environments

Metabolic acidosis in a lactating woman induced by a deliberate ketogenic diet.

ABSTRACT: This article describes a rare case of lactation ketoacidosis in a patient who started a ketogenic diet while nursing an infant and toddler. The patient presented to the ED with a history of nausea, vomiting, and postural dizziness, and was found to have a significant metabolic acidosis and elevated lipase level. The metabolic changes induced in this patient could occur in anyone with high metabolic demands who also is on a strict ketogenic diet. The case highlights the importance of a dietary history in patients with unexplained metabolic derangements

Blood Pressure Reactivity to an Anger Provocation Interview Does Not Predict Incident Cardiovascular Disease Events: The Canadian Nova Scotia Health Survey (NSHS95) Prospective Population Study

We examined the association between blood pressure (BP) reactivity to an anger provocation interview and 10-year incident CVD events in 1,470 adults from the population-based 1995 Nova Scotia Health Survey (NSHS95). In an unadjusted model, those in the highest decile of systolic BP reactivity were more than twice as likely to have an incident CVD event compared to those in the decile with no reactivity (HR = 2.33, 95% CI = 1.15 – 4.69, P = 0.02). However, after adjusting for age and sex, and then also for Framingham risk score, body mass index, and education, this relationship was attenuated and not statistically significant. Diastolic BP reactivity was not associated with CVD incidence in any model. Individual differences in BP reactivity to a laboratory-induced, structured anger provocation interview may not play a major role in clinical CVD endpoints

Is vitamin D deficiency a risk factor for ischemic heart disease in patients with established cardiovascular disease? 10-year follow-up of the Nova Scotia Health Survey

Recent studies have reported that low serum vitamin D levels are associated with a variety of diseases, including cardiovascular disease and in particular ischemic heart disease (IHD). Possible mechanisms underlying this association include increased inflammation, reninangiotensin system upregulation, insulin resistance, altered lipid metabolism, and altered vascular smooth muscle growth and function that lead to hypertension, diabetes, dyslipidemia and atherosclerosis.[1][2] However, few longitudinal studies have explored the association between vitamin D levels and incident IHD. A nested case-control study of male health care professionals found an approximately doubled risk of incident myocardial infarction associated with lower vitamin D levels.[3] Other studies have identified trends between vitamin D levels and incident myocardial infarction but no statistically significant associations, [4][5][6] at least in part due to small sample sizes or short follow-up

E,E-farnesol Inhibits Swarming Motility in \u3cem\u3eBurkholderia cepacia\u3c/em\u3e Through Rhamnolipid Production

Burkholderia cepacia and Candida albicans both exhibit cell-to-cell communication through the use of quorum-sensing molecules (QSM) known as autoinducers. E,E-farnesol is a QSM produced by C. albicans which regulates its conversion from yeast to mycelium. Because there is a positive correlation between the presence of B. cepacia and C. albicans in the lungs of individuals with cystic fibrosis (CF), we examined whether E,E-farnesol had an effect on swarming motility in B. cepacia. Swarming motility was inhibited when B. cepacia was exposed to 250 µM of E,E-farnesol. In addition, there was a 26.8% decrease in rhamnolipid production when cells were grown in the presence of E,E-farnesol. These biosurfactants are known to regulate swarming motility. Changes in the rhamnoplipid concentrations could account for the inhibition of swarming motility observed in the presence of E,E-farnesol. The effect of E,E-farnesol on B. cepacia biofilms was also examined because these complex-community structures are detrimental to the lungs of CF patients and are quorum-sensing regulated. Crystal violet staining showed that E,E-farnesol did not significantly affect biofilm formation in B. cepacia. Further studies are needed to determine the effects of E,E-farnesol on established B. cepacia biofilms and whether it can be combined with traditional antibiotics to disrupt these structures

Comparative Study of Multicellular Tumor Spheroid Formation Methods and Implications for Drug Screening

Improved in vitro models are needed to better understand cancer progression and bridge the gap between in vitro proof-of-concept studies, in vivo validation, and clinical application. Multicellular tumor spheroids (MCTS) are a popular method for three-dimensional (3D) cell culture, because they capture some aspects of the dimensionality, cell–cell contact, and cell–matrix interactions seen in vivo. Many approaches exist to create MCTS from cell lines, and they have been used to study tumor cell invasion, growth, and how cells respond to drugs in physiologically relevant 3D microenvironments. However, there are several discrepancies in the observations made of cell behaviors when comparing between MCTS formation methods. To resolve these inconsistencies, we created and compared the behavior of breast, prostate, and ovarian cancer cells across three MCTS formation methods: in polyNIPAAM gels, in microwells, or in suspension culture. These methods formed MCTS via proliferation from single cells or passive aggregation, and therefore showed differential reliance on genes important for cell–cell or cell–matrix interactions. We also found that the MCTS formation method dictated drug sensitivity, where MCTS formed over longer periods of time via clonal growth were more resistant to treatment. Toward clinical application, we compared an ovarian cancer cell line MCTS formed in polyNIPAAM with cells from patient-derived malignant ascites. The method that relied on clonal growth (PolyNIPAAM gel) was more time and cost intensive, but yielded MCTS that were uniformly spherical, and exhibited the most reproducible drug responses. Conversely, MCTS methods that relied on aggregation were faster, but yielded MCTS with grape-like, lobular structures. These three MCTS formation methods differed in culture time requirements and complexity, and had distinct drug response profiles, suggesting the choice of MCTS formation method should be carefully chosen based on the application required

Tumor cell–organized fibronectin maintenance of a dormant breast cancer population

Tumors can undergo long periods of dormancy, with cancer cells entering a largely quiescent, nonproliferative state before reactivation and outgrowth. To understand the role of the extracellular matrix (ECM) in regulating tumor dormancy, we created an in vitro cell culture system with carefully controlled ECM substrates to observe entrance into and exit from dormancy with live imaging. We saw that cell populations capable of surviving entrance into long-term dormancy were heterogeneous, containing quiescent, cell cycle–arrested, and actively proliferating cells. Cell populations capable of entering dormancy formed an organized, fibrillar fibronectin matrix via αvβ3 and α5β1 integrin adhesion, ROCK-generated tension, and TGFβ2 stimulation, and cancer cell outgrowth after dormancy required MMP-2–mediated fibronectin degradation. We propose this approach as a useful, in vitro method to study factors important in regulating dormancy, and we used it here to elucidate a role for fibronectin deposition and MMP activation