136 research outputs found

    The Increase of the Micoporosity and CO2 Adsorption Capacity of the Commercial Activated Carbon CWZ-22 by KOH Treatment

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    The chemical modification of CWZ-22—commercial activated carbon (AC) with KOH‐ to enhance CO2 adsorption was examined. The effect of different impregnation ratios KOH:CWZ-22 from 1 to 4 was studied. The ACs were characterized by CO2 and N2 sorption, Fourier transform infrared (FTIR), SEM, and XRD methods

    CHOP Mediates Endoplasmic Reticulum Stress-Induced Apoptosis in Gimap5-Deficient T Cells

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    Gimap5 (GTPase of the immunity-associated protein 5) has been linked to the regulation of T cell survival, and polymorphisms in the human GIMAP5 gene associate with autoimmune disorders. The BioBreeding diabetes-prone (BBDP) rat has a mutation in the Gimap5 gene that leads to spontaneous apoptosis of peripheral T cells by an unknown mechanism. Because Gimap5 localizes to the endoplasmic reticulum (ER), we hypothesized that absence of functional Gimap5 protein initiates T cell death through disruptions in ER homeostasis. We observed increases in ER stress-associated chaperones in T cells but not thymocytes or B cells from Gimap5−/− BBDP rats. We then discovered that ER stress-induced apoptotic signaling through C/EBP-homologous protein (CHOP) occurs in Gimap5−/− T cells. Knockdown of CHOP by siRNA protected Gimap5−/− T cells from ER stress-induced apoptosis, thereby identifying a role for this cellular pathway in the T cell lymphopenia of the BBDP rat. These findings indicate a direct relationship between Gimap5 and the maintenance of ER homeostasis in the survival of T cells

    A role for NPY-NPY2R signaling in albuminuric kidney disease

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    Albuminuria is an independent risk factor for the progression to end-stage kidney failure, cardiovascular morbidity, and premature death. As such, discovering signaling pathways that modulate albuminuria is desirable. Here, we studied the transcriptomes of podocytes, key cells in the prevention of albuminuria, under diabetic conditions. We found that Neuropeptide Y (NPY) was significantly down-regulated in insulin-resistant vs. insulin-sensitive mouse podocytes and in human glomeruli of patients with early and late-stage diabetic nephropathy, as well as other nondiabetic glomerular diseases. This contrasts with the increased plasma and urinary levels of NPY that are observed in such conditions. Studying NPY-knockout mice, we found that NPY deficiency in vivo surprisingly reduced the level of albuminuria and podocyte injury in models of both diabetic and nondiabetic kidney disease. In vitro, podocyte NPY signaling occurred via the NPY2 receptor (NPY2R), stimulating PI3K, MAPK, and NFAT activation. Additional unbiased proteomic analysis revealed that glomerular NPY-NPY2R signaling predicted nephrotoxicity, modulated RNA processing, and inhibited cell migration. Furthermore, pharmacologically inhibiting the NPY2R in vivo significantly reduced albuminuria in adriamycin-treated glomerulosclerotic mice. Our findings suggest a pathogenic role of excessive NPY-NPY2R signaling in the glomerulus and that inhibiting NPY-NPY2R signaling in albuminuric kidney disease has therapeutic potential. Chronic kidney disease (CKD) is a major global healthcare concern, affecting over 10% of the general population, and frequently occurs secondary to other systemic disorders including diabetes, obesity, hypertension, and the metabolic syndrome. A common early hallmark of CKD is albuminuria, which not only reflects damage to the glomerular filtration barrier (GFB) in the kidney but also is an important independent risk factor for the progression to end-stage renal failure and cardiovascular disease (1⇓–3). Thus, strategies to prevent albuminuria have important therapeutic potential, particularly in the early stages of CKD progression. Podocytes are highly specialized epithelial cells of the glomerulus, lining the urinary side of the filtration barrier. Owing to their complex, dynamic structures and their ability to secrete (and adapt to) a number of growth factors, these cells have a central role in filtration barrier maintenance (4). As such, podocyte damage is a key driver of albuminuria and glomerular disease in numerous settings and occurs early in the pathogenesis of many albuminuric conditions (5⇓⇓⇓–9). While it is well-established that podocyte damage is a major cause of albuminuria (8), the pathways and molecules involved in podocyte injury are incompletely understood. We (10, 11) and others (12, 13) have highlighted the importance of podocyte insulin responses in maintaining glomerular function, and it is now evident that circulating factors associated with common systemic disorders, including diabetes, obesity, and the metabolic syndrome, can directly induce podocyte insulin resistance (14⇓⇓–17) and associated damage (15, 18). In this study, we analyzed the transcriptomes of insulin-sensitive and insulin-resistant podocytes with the aim of identifying molecules that are differentially regulated in podocyte damage, which may play a role in albuminuric kidney disease. This unbiased transcriptome analysis revealed that Neuropeptide Y (Npy) was the most highly down-regulated transcript in insulin-resistant vs. insulin-sensitive podocytes. Analysis of patient cohorts also revealed a significant reduction in glomerular NPY expression in both early and late-stage diabetic nephropathy (DN), as well as in several other human albuminuric conditions. This contrasts with the increased plasma and urinary levels of NPY that are observed in diabetes and CKD (19⇓⇓–22). This prompted us to further investigate the potential role of NPY (and NPY signaling) in the podocyte and glomerulus

    Antimicrobial activity and rutin identification of honey produced by the stingless bee Melipona compressipes manaosensis and commercial honey

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    Background: Honey has been identified as a potential alternative to the widespread use of antibiotics, which are of significant concern considering the emergence of resistant bacteria. In this context, this study aimed to evaluate the antimicrobial activity of honey samples produced by a stingless bee species and by Apis sp. against pathogenic bacteria, as well as to identify the presence of phenolic compounds.Methods: Honey samples from the stingless bee M. compressipes manaosensis were collected twice, during the dry and rainy seasons. Three commercial honey samples from Apis sp. were also included in this study. Two different assays were performed to evaluate the antibacterial potential of the honey samples: agar-well diffusion and broth macrodilution. Liquid-liquid extraction was used to assess phenolic compounds from honey. HPLC analysis was performed in order to identify rutin and apigenin on honey samples. Chromatograms were recorded at 340 and 290 nm.Results: Two honey samples were identified as having the highest antimicrobial activity using the agar diffusion method. Honey produced by Melipona compressipes manaosensis inhibited the growth of Staphylococcus aureus, Escherichia coli (0157: H7), Proteus vulgaris, Shigella sonnei and Klebsiella sp. A sample of honey produced by Apis sp. also inhibited the growth of Salmonella paratyphi. The macrodilution technique presented greater sensitivity for the antibacterial testing, since all honey samples showed activity. Flavonoid rutin was identified in the honey sample produced by the stingless bee.Conclusions: Honey samples tested in this work showed antibacterial activity against Gram-positive and Gram-negative bacteria. The results reported herein highlight the potential of using honey to control bacterial growth. © 2013 Pimentel et al.; licensee BioMed Central Ltd
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