Silver ion imprinted polymer nanobeads based on a mixed aza-thioether crown containing a 1,10-phenanthroline subunit for solid phase extraction and for voltammetric and potentiometric silver sensors

A new nano-sized silver(I) ion-imprinted polymer (IIP) was prepared via precipitation copolymerization using ethyleneglycol dimethacrylate, as a cross-linking agent in the presence of Ag+ and an aza-thioether crown containing a 1,10-phenanthroline subunit as a highly selective complexing agent. The imprint silver(I) ion was removed from the polymeric matrix using a 1.0 M HNO3 solution. The resulting powder material was characterized using IR spectroscopy and scanning electron microscopy. The SEM micrographs showed colloidal nanoparticles of about 52 nm and 75 nm in diameter and slightly irregular in shape for leached and unleached IIPs, respectively. The optimal pH for quantitative enrichment was 6.0 and maximum sorbent capacity of the prepared IIP for Ag+ was 18.08 mmol g-1. The relative standard deviation and limit of detection (LOD = 3Sb/m) for flame atomic absorption spectrometric determination of silver(I) ion, after its selective extraction by the prepared IIP nanobeads, were evaluated as 2.42% and 2.2 10-8 M, respectively. The new Ag+-IIP was also applied as a suitable sensing element to the preparation of highly selective and sensitive voltammetric and potentiometric sensors for ultra trace detection of silver(I) ion in water samples, with low limits of detection

Diabetic retinopathy pathogenesis and the ameliorating effects of melatonin; involvement of autophagy, inflammation and oxidative stress

Diabetic retinopathy (DR), a microvascular complication of diabetes mellitus (DM), remains as one of the major causes of vision loss worldwide. The release of pro-inflammatory cytokines and the adhesion of leukocytes to retinal capillaries are initial events in DR development. Inflammation, ER stress, oxidative stress and autophagy are major causative factors involved in the pathogenesis of DR. Diabetes associated hyperglycemia leads to mitochondrial electron transport chain dysfunction culminating in a rise in ROS generation. Since mitochondria are the major source of ROS production, oxidative stress induced by mitochondrial dysfunction also contributes to the development of diabetic retinopathy. Autophagy increases in the retina of diabetic patients and is regulated by ER stress, oxidative stress and inflammation-related pathways. Autophagy functions as a double-edged sword in DR. Under mild stress, autophagic activity can lead to cell survival while during severe stress, dysregulated autophagy results in massive cell death and may have a role in initiation and exacerbation of DR. Melatonin and its metabolites play protective roles against inflammation, ER stress and oxidative stress due to their direct free radical scavenger activities and indirect antioxidant activity via the stimulation antioxidant enzymes including glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. Melatonin also acts as a cell survival agent by modulating autophagy in various cell types and under different conditions through amelioration of oxidative stress, ER stress and inflammation. Herein, we review the possible effects of melatonin on diabetic retinopathy, focusing on its ability to regulate autophagy processes. © 201

Diabetic retinopathy pathogenesis and the ameliorating effects of melatonin; involvement of autophagy, inflammation and oxidative stress

Diabetic retinopathy (DR), a microvascular complication of diabetes mellitus (DM), remains as one of the major causes of vision loss worldwide. The release of pro-inflammatory cytokines and the adhesion of leukocytes to retinal capillaries are initial events in DR development. Inflammation, ER stress, oxidative stress and autophagy are major causative factors involved in the pathogenesis of DR. Diabetes associated hyperglycemia leads to mitochondrial electron transport chain dysfunction culminating in a rise in ROS generation. Since mitochondria are the major source of ROS production, oxidative stress induced by mitochondrial dysfunction also contributes to the development of diabetic retinopathy. Autophagy increases in the retina of diabetic patients and is regulated by ER stress, oxidative stress and inflammation-related pathways. Autophagy functions as a double-edged sword in DR. Under mild stress, autophagic activity can lead to cell survival while during severe stress, dysregulated autophagy results in massive cell death and may have a role in initiation and exacerbation of DR. Melatonin and its metabolites play protective roles against inflammation, ER stress and oxidative stress due to their direct free radical scavenger activities and indirect antioxidant activity via the stimulation antioxidant enzymes including glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. Melatonin also acts as a cell survival agent by modulating autophagy in various cell types and under different conditions through amelioration of oxidative stress, ER stress and inflammation. Herein, we review the possible effects of melatonin on diabetic retinopathy, focusing on its ability to regulate autophagy processes. © 201

Comparative phenotypic characterization of human colostrum and breast milk-derived stem cells

There is a diverse population of stem cells in human breast milk that can be employed for therapeutic purposes as a reservoir of cells. The current study mainly aimed to determine the nature markers expressing on stem cells. For this aim, the expression of embryonic stem cell markers, as well as the expression of endothelial, mesenchymal, neural, and hematopoietic markers were evaluated by the flow cytometry analysis in fresh colostrum, breast milk, and cultured colostrum samples. The results showed that the embryonic (OCT4, SOX2, HLA-DR), hematopoietic (CD33, CD45, CD117), neural (CD133, Nestin), and mesenchymal (CD44, SCA1) stem cell markers present in colostrum had higher expression in comparison with their counterpart markers in fresh breast milk. The expression markers of stem cells in colostrum following a 2-week culture period were significantly increased compared with their counterpart markers in colostrum before the culture process. In the culture of breastmilk, cells were not observed adherent cells and colonies. Our findings form flow cytometry and cell culture suggest that the lactation stage could be one of the factors influencing the stem cell population and, consequently, the cultivation of breastmilk cells. The present study indicates that colostrum is a tremendous source of stem cells that could be applied in cell-based research. © 2020, Japan Human Cell Society and Springer Japan KK, part of Springer Nature