5,333 research outputs found
In Utero Transplantation of Placenta-Derived Mesenchymal Stromal Cells for Potential Fetal Treatment of Hemophilia A.
Hemophilia A (HA) is an X-linked recessive disorder caused by mutations in the factor VIII ( FVIII) gene leading to deficient blood coagulation. The current standard of care is frequent infusions of plasma-derived FVIII or recombinant B-domain-deleted FVIII (BDD-FVIII). While this treatment is effective, many patients eventually develop FVIII inhibitors that limit the effectiveness of the infused FVIII. As a monogenic disorder, HA is an ideal target for gene or cell-based therapy. Several studies have investigated allogeneic stem cell therapy targeting in utero or postnatal treatment of HA but have not been successful in completely correcting HA. Autologous in utero transplantation of mesenchymal stem cells is promising for treatment of HA due to the naive immune status of the fetal environment as well as its potential to prevent transplant rejection and long-term FVIII inhibitor formation. HA can be diagnosed by chorionic villus sampling performed during the first trimester (10 to 13 wk) of gestation. In this study, we used an established protocol and isolated placenta-derived mesenchymal stromal cells (PMSCs) from first trimester chorionic villus tissue and transduced them with lentiviral vector encoding the BDD-FVIII gene. We show that gene-modified PMSCs maintain their immunophenotype and multipotency, express, and secrete high levels of active FVIII. PMSCs were then transplanted at embryonic day 14.5 (E14.5) into wild-type fetuses from time-mated pregnant mice. Four days after birth, pups were checked for engraftment, and varying levels of expression of human green fluorescent protein were found in the organs tested. This study shows feasibility of the approach to obtain PMSCs from first trimester chorionic villus tissue, genetically modify them with the FVIII gene, and transplant them in utero for cell-mediated gene therapy of HA. Future studies will involve evaluation of long-term engraftment, phenotypic correction in HA mice, and prevention of FVIII inhibitor development by this approach
Beat that Word : How Listeners Integrate Beat Gesture and Focus in Multimodal Speech Discourse
Peer reviewedPublisher PD
Reactions of Chlorambucil and its main metabolite, Phenylacetic Acid Mustard, with 2’-deoxyribonucleosides and Calf Thymus DNA
Chlorambucil is an anticancer agent used in the treatment of a variety of cancers, especially in chronic lymphocytic leukemia, and autoimmune diseases. Nevertheless, chlorambucil is potentially mutagenic, teratogenic and carcinogenic.
The high antitumor activity and high toxicity of chlorambucil and its main metabolite, phenylacetic acid mustard, to normal tissues have been known for a long time. Despite this, no detailed chemical data on their reactions with biomolecules in aqueous media have been available.
The aim of the work described in this thesis was to analyze reactions of chlorambucil with 2’-deoxyribonucleosides and calf thymus DNA in aqueous buffered solution, at physiological pH, and to identify and characterize all adducts by using modern analyzing methods. Our research was also focused on the reactions of phenylacetic acid mustard with 2’-deoxynucleosides under similar conditions.
A review of the literature consisting of general background of nucleic acids, alkylating agents and ultraviolet spectroscopy used to identify the purine and pyrimidine nucleosides, as well as the results from experimental work are presented and discussed in this doctoral thesis.Siirretty Doriast
Resilience in 2020
In fall 2018, the S. D. Bechtel, Jr. Foundation, along with fellow funders and the authors of this report, set out to study what it takes for nonprofits to survive and even thrive amid disruption, and to better understand how grantmakers can help grow this resilience. "Resilience" was defined as a nonprofit's ability to respond effectively to change and adapt successfully to new and unforeseen circumstances while staying true to mission. Ultimately, seven characteristics emerged as critical to organizational resilience, presented in the resulting report, Resilience at Work. None of the stressors profiled in the original study reached the magnitude of the multiple and interconnected crises that defined 2020 – the pandemic, the uprising for Black lives and racial justice, the economic downturn, the crescendo of natural disasters. The authors wanted to know: What does it take for nonprofits to be resilient in the face of the profound and far-reaching change and uncertainty that no organization was immune from in 2020? Can nonprofits bounce back better equipped to weather future crises? To find out, the S. D. Bechtel, Jr. Foundation commissioned this update
Earnings Management through Capitalizing Operating Costs: Evidence from Accounting for Policy Acquisition Costs in the Insurance Industry
We examine whether managers of public insurers use reporting discretion in capitalizing policy acquisition costs to manage earnings, and the extent to which accounting standards that provide guidance in practice could deter insurers from managing earnings. The accounting standard, ASU 2010-26, establishes a higher threshold at which acquisition costs meet eligibility for deferral. We expect this guidance to reduce the discretion afforded to managers to categorize acquisition costs as an asset. We find empirical evidence that public insurers manage earnings through capitalizing acquisition costs before ASU 2010-26, which became effective in 2012, but not after 2012. We also find that this earnings management is achieved primarily through capitalizing discretionary rather than nondiscretionary acquisition costs. Furthermore, the capitalized acquisition costs are more significantly associated with contemporaneous stock returns and future insurance premiums in the period after ASU 2010-26, suggesting that the capitalization of acquisition costs under the ASU 2010-26 guidance is more value relevant for investors. Taken together, our empirical results indicate that public insurers manage earnings through capitalizing rather than expensing acquisition costs, and that accounting standards that limit such discretion can help reduce this pattern of earnings management and increase the value relevance of the accounting information
Resilience at Work: How Nonprofits Adapt to Disruption. How Funders Can Help.
Today and in the future, there is one thing social change leaders can be sure of: they will experience disruption, uncertainty, and significant change. Whether recovering from a hurricane, navigating global health concerns, responding to shifts in public policy, or regrouping after the departure of a top leader, nonprofits that get intentional about cultivating organizational resilience are better at anticipating and adapting to disruption.Resilience is critical for surviving these turbulent times. Nonprofit organizational resilience is the ability to respond effectively to change and adapt successfully to new and unforeseen circumstances while staying true to mission. At their best, resilient nonprofits respond to disruptions as tipping points, rather than tragedies, finding new opportunities to learn, grow, evolve, and, ultimately, better serve their communities.So, what does it take for nonprofits to survive and even thrive amid shocks? This research points to seven crucial characteristics, and surfaces principles and practices for funders who seek to boost grantee resilience
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Hypoxic Preconditioning Enhances Survival and Proangiogenic Capacity of Human First Trimester Chorionic Villus-Derived Mesenchymal Stem Cells for Fetal Tissue Engineering.
Prenatal stem cell-based regenerative therapies have progressed substantially and have been demonstrated as effective treatment options for fetal diseases that were previously deemed untreatable. Due to immunoregulatory properties, self-renewal capacity, and multilineage potential, autologous human placental chorionic villus-derived mesenchymal stromal cells (CV-MSCs) are an attractive cell source for fetal regenerative therapies. However, as a general issue for MSC transplantation, the poor survival and engraftment is a major challenge of the application of MSCs. Particularly for the fetal transplantation of CV-MSCs in the naturally hypoxic fetal environment, improving the survival and engraftment of CV-MSCs is critically important. Hypoxic preconditioning (HP) is an effective priming approach to protect stem cells from ischemic damage. In this study, we developed an optimal HP protocol to enhance the survival and proangiogenic capacity of CV-MSCs for improving clinical outcomes in fetal applications. Total cell number, DNA quantification, nuclear area test, and cell viability test showed HP significantly protected CV-MSCs from ischemic damage. Flow cytometry analysis confirmed HP did not alter the immunophenotype of CV-MSCs. Caspase-3, MTS, and Western blot analysis showed HP significantly reduced the apoptosis of CV-MSCs under ischemic stimulus via the activation of the AKT signaling pathway that was related to cell survival. ELISA results showed HP significantly enhanced the secretion of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by CV-MSCs under an ischemic stimulus. We also found that the environmental nutrition level was critical for the release of brain-derived neurotrophic factor (BDNF). The angiogenesis assay results showed HP-primed CV-MSCs could significantly enhance endothelial cell (EC) proliferation, migration, and tube formation. Consequently, HP is a promising strategy to increase the tolerance of CV-MSCs to ischemia and improve their therapeutic efficacy in fetal clinical applications
Persistent Vascular Collagen Accumulation Alters Hemodynamic Recovery from Chronic Hypoxia
Pulmonary arterial hypertension (PAH) is caused by narrowing and stiffening of the pulmonary arteries that increase pulmonary vascular impedance (PVZ). In particular, small arteries narrow and large arteries stiffen. Large pulmonary artery (PA) stiffness is the best current predictor of mortality from PAH. We have previously shown that collagen accumulation leads to extralobar PA stiffening at high strain (Ooi et al. 2010). We hypothesized that collagen accumulation would increase PVZ, including total pulmonary vascular resistance (Z0), characteristic impedance (ZC), pulse wave velocity (PWV) and index of global wave reflections (Pb/Pf), which contribute to increased right ventricular afterload. We tested this hypothesis by exposing mice unable to degrade type I collagen (Col1a1R/R) to 21 days of hypoxia (hypoxia), some of which were allowed to recover for 42 days (recovery). Littermate wild-type mice (Col1a1+/+) were used as controls. In response to hypoxia, mean PA pressure (mPAP) increased in both mouse genotypes with no changes in cardiac output (CO) or PA inner diameter (ID); as a consequence, Z0 (mPAP/CO) increased by ∼100% in both genotypes (pZC, PWV and Pb/Pf did not change. However, with recovery, ZC and PWV decreased in the Col1a1+/+ mice and remained unchanged in the Col1a1R/R mice. Z0 decreased with recovery in both genotypes. Microcomputed tomography measurements of large PAs did not show evidence of stiffness changes as a function of hypoxia exposure or genotype. We conclude that hypoxia-induced PA collagen accumulation does not affect the pulsatile components of pulmonary hemodynamics but that excessive collagen accumulation does prevent normal hemodynamic recovery, which may have important consequences for right ventricular function
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