174 research outputs found

    Effects of Dexamethasone on Mesenchymal Stromal Cell Chondrogenesis and Aggrecanase Activity: Comparison of Agarose and Self-Assembling Peptide Scaffolds

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    Objective: Dexamethasone (Dex) is a synthetic glucocorticoid that has pro-anabolic and anticatabolic effects in cartilage tissue engineering systems, though the mechanisms by which these effects are mediated are not well understood. We tested the hypothesis that the addition of Dex to chondrogenic medium would affect matrix production and aggrecanase activity of human and bovine bone marrow stromal cells (BMSCs) cultured in self-assembling peptide and agarose hydrogels. Design: We cultured young bovine and adult human BMSCs in (RADA)[subscript 4] self-assembling peptide and agarose hydrogels in medium containing TGF-β1±Dex and analyzed extracellular matrix composition, aggrecan cleavage products, and the effects of the glucocorticoid receptor antagonist RU-486 on proteoglycan content, synthesis, and catabolic processing. Results: Dex improved proteoglycan synthesis and retention in agarose hydrogels seeded with young bovine cells but decreased proteoglycan accumulation in peptide scaffolds. These effects were mediated by the glucocorticoid receptor. Adult human BMSCs showed minimal matrix accumulation in agarose, but accumulated ~50% as much proteoglycan and collagen as young bovine BMSCs in peptide hydrogels. Dex reduced aggrecanase activity in (RADA)[subscript 4] and agarose hydrogels, as measured by anti-NITEGE Western blotting, for both bovine and human BMSC-seeded gels. Conclusions: The effects of Dex on matrix production are dependent on cell source and hydrogel identity. This is the first report of Dex reducing aggrecanase activity in a tissue engineering culture system.National Science Foundation (U.S.). Graduate Research FellowshipNational Institutes of Health (U.S.) (Grant EB003805

    Delivering Heparin-Binding Insulin-Like Growth Factor 1 with Self-Assembling Peptide Hydrogels

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    Heparin-binding insulin-like growth factor 1 (HB-IGF-1) is a fusion protein of IGF-1 with the HB domain of heparin-binding epidermal growth factor-like growth factor. A single dose of HB-IGF-1 has been shown to bind specifically to cartilage and to promote sustained upregulation of proteoglycan synthesis in cartilage explants. Achieving strong integration between native cartilage and tissue-engineered cartilage remains challenging. We hypothesize that if a growth factor delivered by the tissue engineering scaffold could stimulate enhanced matrix synthesis by both the cells within the scaffold and the adjacent native cartilage, integration could be enhanced. In this work, we investigated methods for adsorbing HB-IGF-1 to self-assembling peptide hydrogels to deliver the growth factor to encapsulated chondrocytes and cartilage explants cultured with growth factor-loaded hydrogels. We tested multiple methods for adsorbing HB-IGF-1 in self-assembling peptide hydrogels, including adsorption prior to peptide assembly, following peptide assembly, and with/without heparan sulfate (HS, a potential linker between peptide molecules and HB-IGF-1). We found that HB-IGF-1 and HS were retained in the peptide for all tested conditions. A subset of these conditions was then studied for their ability to stimulate increased matrix production by gel-encapsulated chondrocytes and by chondrocytes within adjacent native cartilage. Adsorbing HB-IGF-1 or IGF-1 prior to peptide assembly was found to stimulate increased sulfated glycosaminoglycan per DNA and hydroxyproline content of chondrocyte-seeded hydrogels compared with basal controls at day 10. Cartilage explants cultured adjacent to functionalized hydrogels had increased proteoglycan synthesis at day 10 when HB-IGF-1 was adsorbed, but not IGF-1. We conclude that delivery of HB-IGF-1 to focal defects in cartilage using self-assembling peptide hydrogels is a promising technique that could aid cartilage repair via enhanced matrix production and integration with native tissue.National Science Foundation (U.S.). Graduate Research Fellowship ProgramNational Institutes of Health (U.S.) (Grant EB003805)National Institutes of Health (U.S.) (Grant AR060331)Whitaker Health Sciences Fund FellowshipMassachusetts Life Sciences CenterBiomeasure, Inc

    How Do Patients Understand Questions about Lower Urinary Tract Symptoms?:A Qualitative Study of Problems in Completing Urological Questionnaires

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    Lower urinary tract symptoms are common complaints in ageing people. For a urological evaluation of such complaints in men, the International Prostate Symptom Score (IPSS) is used worldwide. Previous quantitative studies have revealed serious problems in completing this questionnaire. In order to gain insight into the nature and causes of these problems, we conducted a qualitative study. Not only the purely verbal IPSS was studied but also two alternatives, including pictograms: the Visual Prostate Symptom Score (VPSS) and the Score Visuel Prostatique en Image (SVPI). Men aged 40 years and over with an inadequate level of health literacy (IHL; n = 18) or an adequate level of health literacy (AHL; n = 47) participated. Each participant filled out one of the three questionnaires while thinking aloud. The analysis of their utterances revealed problems in both health literacy groups with form-filling tasks and subtasks for all three questionnaires. Most noticeable were the problems with the IPSS; the terminology and layout of this form led to difficulties. In the VPSS and SVPI, the pictograms sometimes raised problems. As in previous research on form-filling behavior, an overestimation by form designers of form fillers' knowledge and skills seems to be an important explanation for the problems observed

    The Interplay of RecA-related Proteins and the MND1–HOP2 Complex during Meiosis in Arabidopsis thaliana

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    During meiosis, homologous chromosomes recognize each other, align, and exchange genetic information. This process requires the action of RecA-related proteins Rad51 and Dmc1 to catalyze DNA strand exchanges. The Mnd1–Hop2 complex has been shown to assist in Dmc1-dependent processes. Furthermore, higher eukaryotes possess additional RecA-related proteins, like XRCC3, which are involved in meiotic recombination. However, little is known about the functional interplay between these proteins during meiosis. We investigated the functional relationship between AtMND1, AtDMC1, AtRAD51, and AtXRCC3 during meiosis in Arabidopsis thaliana. We demonstrate the localization of AtMND1 to meiotic chromosomes, even in the absence of recombination, and show that AtMND1 loading depends exclusively on AHP2, the Arabidopsis Hop2 homolog. We provide evidence of genetic interaction between AtMND1, AtDMC1, AtRAD51, and AtXRCC3. In vitro assays suggest that this functional link is due to direct interaction of the AtMND1–AHP2 complex with AtRAD51 and AtDMC1. We show that AtDMC1 foci accumulate in the Atmnd1 mutant, but are reduced in number in Atrad51 and Atxrcc3 mutants. This study provides the first insights into the functional differences of AtRAD51 and AtXRCC3 during meiosis, demonstrating that AtXRCC3 is dispensable for AtDMC1 focus formation in an Atmnd1 mutant background, whereas AtRAD51 is not. These results clarify the functional interactions between key players in the strand exchange processes during meiotic recombination. Furthermore, they highlight a direct interaction between MND1 and RAD51 and show a functional divergence between RAD51 and XRCC3

    Dissection of the Influenza A Virus Endocytic Routes Reveals Macropinocytosis as an Alternative Entry Pathway

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    Influenza A virus (IAV) enters host cells upon binding of its hemagglutinin glycoprotein to sialylated host cell receptors. Whereas dynamin-dependent, clathrin-mediated endocytosis (CME) is generally considered as the IAV infection pathway, some observations suggest the occurrence of an as yet uncharacterized alternative entry route. By manipulating entry parameters we established experimental conditions that allow the separate analysis of dynamin-dependent and -independent entry of IAV. Whereas entry of IAV in phosphate-buffered saline could be completely inhibited by dynasore, a specific inhibitor of dynamin, a dynasore-insensitive entry pathway became functional in the presence of fetal calf serum. This finding was confirmed with the use of small interfering RNAs targeting dynamin-2. In the presence of serum, both IAV entry pathways were operational. Under these conditions entry could be fully blocked by combined treatment with dynasore and the amiloride derivative EIPA, the hallmark inhibitor of macropinocytosis, whereas either drug alone had no effect. The sensitivity of the dynamin-independent entry pathway to inhibitors or dominant-negative mutants affecting actomyosin dynamics as well as to a number of specific inhibitors of growth factor receptor tyrosine kinases and downstream effectors thereof all point to the involvement of macropinocytosis in IAV entry. Consistently, IAV particles and soluble FITC-dextran were shown to co-localize in cells in the same vesicles. Thus, in addition to the classical dynamin-dependent, clathrin-mediated endocytosis pathway, IAV enters host cells by a dynamin-independent route that has all the characteristics of macropinocytosis

    Health state utility and health-related quality of life measures in patients with advanced ovarian cancer

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    Purpose: Measuring health-related quality of life (HRQoL) in ovarian cancer patients is critical to understand the impact of disease and treatment. Preference-based HRQoL measures, called health state utilities, are used specifically in health economic evaluations. Real-world patient-reported data on HRQoL and health state utilities over the long-term course of ovarian cancer are limited. This study aims to determine HRQoL and health state utilities in different health states of ovarian cancer. Methods: This cross-sectional, multicenter study included patients with stage III-IV ovarian cancer in six health states: at diagnosis, during chemotherapy, after cytoreductive surgery (CRS), after chemotherapy, in remission, and at first recurrence. HRQoL was measured using the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire C30, and the ovarian cancer-specific module OV28. Health state utilities were assessed using the EuroQol five-dimension five-level (EQ-5D-5L) questionnaire. Descriptive analyses were performed for each health state. Results: Two hundred thirty-two patients participated, resulting in 319 questionnaires. Median age was 66 years. The lowest HRQoL was observed during chemotherapy and shortly after CRS. Physical and role functioning were most affected and the highest symptom prevalence was observed in the fatigue, nausea, pain, dyspnea, gastrointestinal, neuropathy, attitude, and sexuality domains. Patients in remission had the best HRQoL. Mean utility values ranged from 0.709 (±0.253) at diagnosis to 0.804 (±0.185) after chemotherapy.Conclusions: This study provides clinicians with a valuable resource to aid in patient counseling and clinical decision-making. The utilities, in particular, are crucial for researchers conducting economic analyses to inform policy decisions.</p

    Nuclear immobilization of DsRed1 tagged proteins: A novel tool for studying DNA–protein interactions?

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    AbstractDsRed1 is a red fluorescent protein that can be used as a fusion partner with other proteins to determine their subcellular localization, similarly to the popular green fluorescent proteins (GFP). Here, we report that fusion of DsRed1 to estrogen receptor α (ERα) renders the transcription factor immobile within the nucleus. Furthermore, we show that the immobilization is dependent on DNA interaction and that the binding to the DNA can be direct as well as indirect for DsRed to immobilize with its fusion partners. This observation could provide a new tool to be used for the identification of target genes containing low affinity binding sites for several transcription factors including ERα. In addition, it could be employed for studies on protein–DNA interactions as well as protein–protein interactions during protein complex formation on chromatin in the event of transcription initiation and regulation

    Is There Any Interaction Between Sex and Renal Function Change During Hospital Stay in Patients Hospitalized With Acute Heart Failure?

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    Background: Renal dysfunction is a strong predictor of outcomes in patients with acute heart failure (AHF). However. less is known about how sex may influence the prognostic import of renal function in AHF. Methods and Results: In a post hoc analysis of the ASCEND-HF trial including 5377 patients with AHF (33% female), patients were categorized into 3 groups based on the changes in renal function during their hospital stay. Worsening. stable, and improving renal functions were defined as a >= 20% decrease, a = 20% increase in the estimated glomentlar filtration rate, respectively. The primary outcome was the composite of 30-day all-cause mortality or HF rehospitalization. The median baseline and discharge estimated glomerular filtration rate were 58.4 and 56.9 mL/min/l.73 m(2), respectively. Worsening, stable, and improving renal function was observed in 31.9%, 63.2, and 4.9% of patients. respectively. Worsening renal function was associated with adverse outcomes at 30 days (adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.22-1.76). This association existed in both males and females (aHR 1.42 and aHR 1.56, respectively, both P < .01). There was an interaction between renal function changes and sex (P = .025), because improving renal function was associated with better outcomes in men(aHR 0.29, 95% CI 0.13 0.66) as compared with women (aHR 1.18, 95% CI 0.59 2.35). There was no interaction between the ejection fraction and renal function in association with subsequent outcomes. Conclusions: Irrespective of sex, worsening renal function was associated with poorer outcomes at 30 days in patients with AHF. More studies are warranted to further delineate the possible sex differences in this setting

    Diagnostic accuracy of depression questionnaires in adult patients with diabetes: a systematic review and meta-analysis

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    Importance Comorbid depression is common among patients with diabetes and has severe health consequences, but often remains unrecognized. Several questionnaires are used to screen for depression. A systematic review and meta-analysis regarding the diagnostic accuracy of depression questionnaires in adults with diabetes is unavailable. Objective To conduct a systematic review and meta-analysis to evaluate the diagnostic accuracy of depression questionnaires in adults with type 1 or type 2 diabetes. Data sources PubMed, Embase and PsycINFO were searched from inception to 28 February 2018. Study selection Studies were included when the diagnostic accuracy of depression questionnaires was assessed in a diabetes population and the reference standard was a clinical interview. Data extraction and synthesis Data extraction was performed by one reviewer and checked by another. Two reviewers independently conducted the quality assessment (QUADAS-2). Diagnostic accuracy was pooled in bivariate random effects models. This study is reported according to PRISMA-DTA and is registered with PROSPERO (CRD42018092950). Main Outcome(s) and measure(s) Diagnostic accuracy, expressed as sensitivity and specificity, of depression questionnaires in an adult diabetes population. Results A total 6,097 peer-reviewed articles were screened. Twenty-one studies (N= 5,703 patients) met the inclusion criteria for the systematic review. Twelve different depression questionnaires were identified, of which the CES-D (n=6 studies) and PHQ-9 (n=7 studies) were the most frequently evaluated. Risk of bias was unclear for multiple domains in the majority of studies. In the meta-analyses, five (N= 1,228) studies of the CES-D (≥16), five (N= 1,642) of the PHQ-9 (≥10) and four (N=822) of the algorithm of the PHQ-9 were included in the pooled analysis. The CES-D (≥16) had a pooled sensitivity of 85.0% (95%CI, 71.3-92.8%) and a specificity of 71.6% (95%CI, 62.5-79.2%); the PHQ-9 (≥10) had a sensitivity of 81.5% (95%CI, 57.1-93.5%) and a specificity of 79.7% (95%CI, 62.1-90.4%). The algorithm for the PHQ-9 had a sensitivity of 60.9% (95%CI, 52.3-50 90.8%) and a specificity of 64.0% (95%CI, 53.0-93.9%). Conclusions and relevance This review indicates that the CES-D had the highest sensitivity, whereas the PHQ-9 had the highest specificity, although confidence intervals were wide and overlapping. The algorithm for the PHQ-9 had the lowest sensitivity and specificity. Given the variance in results and suboptimal reporting of studies, further high quality studies are needed to confirm the diagnostic accuracy of these depression questionnaires in patients with diabetes

    Cyclooxygenase inhibitors use is associated with reduced risk of esophageal adenocarcinoma in patients with Barrett's esophagus: A meta-analysis

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    Background: Esophageal adenocarcinoma (EAC) has high mortality and is increasing in incidence. Barrett's esophagus (BE) increases the risk for EAC. Studies have reported inconsistent findings on the association between use of cyclooxygenase (COX) inhibitors and the risk of neoplastic progression in BE patients. Therefore, we performed a meta-analysis to investigate this association. Methods: A meta-analysis was undertaken among a total of 9 observational studies using fixed- and random-effects models, comprising 5446 participants; 605 had EAC or high-grade dysplasia (HGD). Results: Overall, COX inhibitors use was associated with a reduced risk of EAC/HGD among BE patients (relative risk (RR)=0.64, 95% confidence interval (CI)=0.53-0.77). Aspirin use also reduced the risk of EAC/HGD (RR=0.63, 95% CI=0.43-0.94), as well as non-aspirin COX inhibitors (RR=0.50, 95% CI=0.32-0.78). The chemopreventive effect seemed to be independent of duration response. Conclusions: Cyclooxygenase inhibitors use is associated with a reduced risk of developing EAC in patients with BE. Both low-dose aspirin and non-aspirin COX inhibitors are associated with a reduced risk of neoplasia. More well-designed randomised controlled trials are needed to increase our understanding of the chemopreventive effect of COX inhibitors
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