Minia University

About: Minia University is a education organization based out in Minya, Egypt. It is known for research contribution in the topics: Population & Medicine. The organization has 4967 authors who have published 8986 publications receiving 108384 citations.

GPCR-mediated EGF receptor transactivation regulates TRPV4 action in the vasculature.

Abstract: Background and Purpose: Transient receptor potential vanilloid-4 (TRPV4) is a calcium-permeant ion channel that is known to affect vascular function. The ability of TRPV4 to cause a vasoconstriction in blood vessels has not yet been mechanistically examined. Further in neuronal cells, TRPV4 signalling can be potentiated by GPCR activation. Thus, we studied the mechanisms underlying the vascular contractile action of TRPV4 and the GPCR-mediated potentiation of such vasoconstriction, both of which are as yet unappreciated aspects of TRPV4 function. Experimental Approach: The mechanisms of TRPV4-dependent regulation of vascular tone in isolated mouse aortae were studied using wire myography. TRPV4-dependent calcium signalling and prostanoid production was studied in cultured human umbilical vein endothelial cells (HUVECs). Key Results: In addition to the well-documented vasorelaxation response triggered by TRPV4 activation, we report here a TRPV4-triggered vasoconstriction in the mouse aorta that involves a COX-generated Tx receptor (TP) agonist that acts in a MAPK and Src kinase signalling dependent manner. This constriction is potentiated by activation of the GPCRs for angiotensin (AT(1) receptors) or proteinases (PAR1 and PAR2) via transactivation of the EGF receptor and a process involving PKC. TRPV4-dependent vascular contraction can be blocked by COX inhibitors or with TP antagonists. Further, TRPV4 activation in HUVECs stimulated Tx release as detected by an elisa. Conclusion and Implications: We conclude that the GPCR potentiation of TRPV4 action and TRPV4-dependent Tx receptor activation are important regulators of vascular function and could be therapeutically targeted in vascular diseases.

Thermal stability of some commercial natural and synthetic antioxidants and their mixtures

Abstract: The thermal stability of some commercially available antioxidants alone or in binary or ternary mixtures was investigated in order to find the optimal combination of antioxidants for food processing. The synthetic antioxidants used were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG) and tertiary-butyhydroquinone (TBHQ). Other antioxidants such as ascorbyl palmitate (AP), mixed tocopherols (TOCO) and monoacylglycerol citrate (MGC) were also employed. The effectiveness of these antioxidants and their combinations was assessed using the Rancimat test by measuring the induction period for the oxidation of sunflower oil after heating at 180C for 1 h and comparing it to the oxidation kinetics of the oil without added antioxidants. All antioxidants and their binary or ternary mixtures showed different degrees of thermal instability. TBHQ individually, among all the examined antioxidants, showed the highest thermal stability. On the other hand, AP as an antioxidant in sunflower oil exhibited low stability during heating. The thermal stability of AP could be enhanced by the addtion of BHA or BHT in binary mixtures at a ratio of 1:3 (w/w). In addition, the ternary mixture of AP, TOCO and MGC (65:25:10) in sunflower oil also showed a higher stability to thermal inactivation. However, the ternary mixture containing 0.13% AP, 0.05% TBHQ and 0.02% MGC provided the optimal protection during thermal treatment. Although a combination of 0.13% BHT, 0.05% AP and 0.02% MG was very effective synergistically at room temperature, it showed a higher susceptibility to thermal inactivation. It was

Antidiabetic Potency, Antioxidant Effects, and Mode of Actions of Citrus reticulata Fruit Peel Hydroethanolic Extract, Hesperidin, and Quercetin in Nicotinamide/Streptozotocin-Induced Wistar Diabetic Rats.

Abstract: This study is aimed at assessing the antihyperglycemic, antihyperlipidemic, and antioxidant effects of Citrus reticulata (C reticulata) fruit peel hydroethanolic extract and two flavonoids, hesperidin and quercetin, in nicotinamide (NA)/streptozotocin- (STZ-) induced type 2 diabetic rats In addition, GC-MS and HPLC-MS analyses of the extract were performed and the results indicated the presence of multiple flavonoids including hesperidin, quercetin, naringin, and polymethoxylated flavones (nobiletin and tangeretin) To achieve the aim of the study, diabetic rats with NA/STZ-induced T2DM were orally treated with C reticulata fruit peel hydroethanolic extract, hesperidin, and quercetin at a dose of 100 mg/kg bw/day for four weeks The treatments with C reticulata fruit peel extract, hesperidin, and quercetin significantly ameliorated the impaired oral glucose tolerance; the elevated serum fructosamine level; the diminished serum insulin and C-peptide levels; the altered HOMA-IR, HOMA-IS, and HOMA-β cell function; the decreased liver glycogen content; the increased liver glucose-6-phosphatase and glycogen phosphorylase activities; the deleteriously affected serum lipid profile; the elevated serum AST and ALT activities; and the raised serum creatinine and urea levels in the diabetic rats The treatments also produced remarkable improvement in the antioxidant defense system manifested by a decrease in the elevated liver lipid peroxidation and an increase in the lowered glutathione content and GPx, GST, and SOD activities Furthermore, the three treatments enhanced the mRNA expression of GLUT-4 and the insulin receptor β-subunit, but only quercetin produced a significant increase in the expression of adiponectin in adipose tissue of diabetic rats In conclusion, C reticulata fruit peel hydroethanolic extract, hesperidin, and quercetin have potent antidiabetic effects which may be mediated through their insulinotropic effects and insulin-sensitizing actions In addition, the alleviation of the antioxidant defense system by the extract, hesperidin, and naringin may have an important action to enhance the antidiabetic actions and to improve liver and kidney functions in NA/STZ-induced diabetic rats

Trichoderma populations from alkaline agricultural soil in the Nile valley, Egypt, consist of only two species

Abstract: The biodiversity of Trichoderma was studied in the Northern half of the Nile valley in Egypt. 20 strains were isolated from 9 different geographic locations, representing 19 different habitats, all with a pH between 7.3 and 8.4. Only T. harzianum (three ITS1/2 haplotypes and three RAPD-genotypes) and the anamorph of Hypocrea orientalis were found. One of the T. harzianum haplotypes (4 strains) is new. The occurrence of T. harzianum haplotypes and of H. orientalis appeared to be essentially independent of the habitat (pH, plant, soil type), and also did not correlate with biochemical properties (cellulase and chitinase activity) of the individual strains. These two taxa seem to be indigenous to the Nile valley, their presence not being influenced by the agricultural history of the soils.