Cell-extracellular matrix interactions regulate neural differentiation of human embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>Interactions of cells with the extracellular matrix (ECM) are critical for the establishment and maintenance of stem cell self-renewal and differentiation. However, the ECM is a complex mixture of matrix molecules; little is known about the role of ECM components in human embryonic stem cell (hESC) differentiation into neural progenitors and neurons.</p> <p>Results</p> <p>A reproducible protocol was used to generate highly homogenous neural progenitors or a mixed population of neural progenitors and neurons from hESCs. This defined adherent culture system allowed us to examine the effect of ECM molecules on neural differentiation of hESCs. hESC-derived differentiating embryoid bodies were plated on Poly-D-Lysine (PDL), PDL/fibronectin, PDL/laminin, type I collagen and Matrigel, and cultured in neural differentiation medium. We found that the five substrates instructed neural progenitors followed by neuronal differentiation to differing degrees. Glia did not appear until 4 weeks later. Neural progenitor and neuronal generation and neurite outgrowth were significantly greater on laminin and laminin-rich Matrigel substrates than on other 3 substrates. Laminin stimulated hESC-derived neural progenitor expansion and neurite outgrowth in a dose-dependent manner. The laminin-induced neural progenitor expansion was partially blocked by the antibody against integrin α6 or β1 subunit.</p> <p>Conclusion</p> <p>We defined laminin as a key ECM molecule to enhance neural progenitor generation, expansion and differentiation into neurons from hESCs. The cell-laminin interactions involve α6β1 integrin receptors implicating a possible role of laminin/α6β1 integrin signaling in directed neural differentiation of hESCs. Since laminin acts in concert with other ECM molecules <it>in vivo</it>, evaluating cellular responses to the composition of the ECM is essential to clarify further the role of cell-matrix interactions in neural derivation of hESCs.</p

Tau Causes Synapse Loss without Disrupting Calcium Homeostasis in the rTg4510 Model of Tauopathy

Neurofibrillary tangles (NFTs) of tau are one of the defining hallmarks of Alzheimer’s disease (AD), and are closely associated with neuronal degeneration. Although it has been suggested that calcium dysregulation is important to AD pathogenesis, few studies have probed the link between calcium homeostasis, synapse loss and pathological changes in tau. Here we test the hypothesis that pathological changes in tau are associated with changes in calcium by utilizing in vivo calcium imaging in adult rTg4510 mice that exhibit severe tau pathology due to over-expression of human mutant P301L tau. We observe prominent dendritic spine loss without disruptions in calcium homeostasis, indicating that tangles do not disrupt this fundamental feature of neuronal health, and that tau likely induces spine loss in a calcium-independent manner

Refining the Experimental Analysis of Academic Skills Deficits: Part I. An Investigation of Variables That Affect Generalized Oral Reading Performance

Experimental analyses for improving reading fluency deficits have rarely targeted generalized increases in academic responding. As a consequence, the variables that may help students to generalize newly learned forms of academic responding like reading are not well understood. Furthermore, experimental analyses of reading fluency interventions have not systematically examined difficulty level as a variable that may affect instructional outcomes. The experiment reported in this paper expands (a) the measurement of the dependent variables to include generalized increases across tasks (reading passages) and (b) the combination of independent variables used to produce measurable generalized increases. The results demonstrate the importance of combining reward and instructional variables (including difficulty level) to produce generalized increases and how those variables can be meaningfully investigated prior to making treatment recommendations

Refining The Experimental Analysis of Academic Skills Deficits: Part II. Use of Brief Experimental Analysis to Evaluate Reading Fluency Treatments

The technology of brief experimental analysis is just beginning to be used for identification of effective treatments for individual students who experience difficulty with oral reading fluency. In this study, the effect of a reading fluency treatment package was examined on easy and hard passages, and generalization was assessed on passages with high content overlap. The results suggest that the treatment package increased reading fluency for all 3 students. Effects were moderated by difficulty level for all 3 students. Results are discussed in terms of future refinements to the procedures, validation of the methods, and potential applications in clinical and school settings

High prevalence of fluoroquinolone-resistant UTI among US emergency department patients diagnosed with urinary tract infection, 2018–2020

Background: Uropathogen resistance, fluoroquinolone-resistance (FQR), and extended spectrum beta-lactamase (ESBL), has been observed to be emerging worldwide with prevalences above recommended thresholds for routine empirical treatment. The primary aim of our study was to determine the prevalence of FQR from a geographically diverse sample of United States emergency departments (EDs). Methods: We conducted a multi-center, observational cohort study using a network of 15 geographically diverse US EDs. All patients ≥18 years of age with the primary or secondary diagnosis of urinary tract infection (UTI) in the ED identified using International Classification of Diseases (ICD-10) diagnosis code of cystitis, pyelonephritis, or UTI from 2018 to 2020 were included. We calculated descriptive statistics for uropathogens and susceptibilities. Logistic regression analysis was used to identify antimicrobial resistance risk factors associated with FQR Escherichia coli. Results: Among 3779 patients who met inclusion criteria, median age was 62.9 years (interquartile range [IQR]: 41–77.6) and 76.3% were female. The most common diagnoses were complicated (41.2%) and uncomplicated cystitis (40.3%). E. coli was the most common pathogen (63.2%), followed by Klebsiella pneumoniae (13.2%) and Enterococcus species (5.8%). Across all sites, overall E. coli FQ-resistance prevalence was 22.1%, ranging from 10.5 to 29.7% by site. The prevalence of ESBL-producing uropathogen was 7.4%, ranging from 3.6% to 11.6% by site. Previous IV or oral antimicrobial use in the past 90-days and history of a multi-drug resistant pathogen were associated with FQ-resistant E. coli (odds ratio [OR] 2.68, 95% confidence interval [CI]: 2.04–3.51, and OR 6.93, 95% CI: 4.95–9.70, respectively). Of the patients who had FQ-resistant E. coli or an ESBL-producing uropathogen isolated, 116 (37.1%) and 61 (36.7%) did not have any documented risk factors for resistance. Conclusion: FQ-resistant E. coli is widely prevalent across US sites highlighting the need for ongoing monitoring of antimicrobial resistance and, at some locations, modification of empirical treatments