Purification and characterization of pectin methylesterase isoenzymes from orange peel

Pectin methylesterase [PME] isoenzymes from Citrus sinensis [Balady orange] peel have been purified and characterized. The purification procedure included CM-cellulose, DEAE-cellulose and Sephacryl S-200 columns. PMEl, PME2 and PME4 were purified to homogeneity. The molecular weights of PMEl, PME2 and PME4 were determined using Sephacryl S-200 column and estimated to be 23,000,·47,400 and 79,500 Da, respectively. PME1, PME2 and PME4 had isoelectric points of 5.4, 5.9 and 5.6, and pH optima of 6.0, 6.0 and 5.5, respectively. Maximum PME activity was reached at 50 mM NaCl for PMEl and PME4, and 25 mM NaCl for PME2. Km values of PMEl, PME2 and PME4 using pectin with degree of esterification [DE] of 8% were 0.55, 1.0 and 3.33 mg pectin/ml, respectively. The affinity of PMEs was increased with the increasing of the DE of pectin. The time-dependent heat-inactivation curves for the three isoforms exhibited exponential behaviour and showed that PMEl was more heat resistant than PME2 and PME4. Effect of pH on enzyme stability, kinetic properties [Vmax and Keat] of isoenzymes, and effect of different metal cations on enzyme activity were investigated. A study of the inhibitory effect of ferrous sulfate [FeSO[4]] on the PME activity in freshly prepared Balady orange juice revealed that 1 mM FeSO[4] was the best concentration that maintained the homogeneity and stability of the juice

Evaluation of some biochemical parameters as atherogenic risk factors in chronic renal failure patients undergoing hemodialysis

In chronic hemodialysis [HD] patients, atherosclerotic vascular disease [AVD] is a major cause of cardiovascular morbidity and mortality. This study aimed to evaluate the possibility of using .plasma homocysteine [Hcy], nitric oxide [NO], and endothelin-1 [ET-1]; and serum proinflammatory cytokines such as interleukin-6 [lL-6] and tumor necrosis factor-alpha [TNF-alpha] as reliable parameters in the course of prediction of AVD in HD patients. Therefore, these parameters were determined in 15 HD patients with no signs of cardiovascular disease [HD group], and in 12 HD patients that had an evidence of clinically significant AVD [HD and AVD group]. Patient groups were compared with 10 age-matched healthy subjects [control group]. The concentration of Hcy, ET-1, lL-6 and NH: was significantly higher while the concentration of NO was significantly lower in HD group and HD and AVD group than in control. The level of Hcy, ET-1, lL-6 and TNF-alpha was significantly higher while the level of NO was significantly lower in HD and AVD group than in the HD group. In both patient groups, Hcy and ET-1 correlated Negatively with NO while ET-1 correlated positively with Hcy, lL-6 and TNF-alpha. Moreover, lL-6 correlated positively with TNF-a. In conclusion, hyperhomocysteinemia, low NO and high ET-1, IL-6 and NH: could be considered as risk factors for AVD in HD patients. Therefore, improvement of NO production, blockage of endothelin receptors, and reduction of proinflammatory cytokines seem to be reasonable recommended approaches of treatment in HD patients to reduce the risk of development of AVD

Bee honey and Nigella sativa inhibit nitric oxide mediated cytochrome C release and down regulation of connexin 43 induced by methylnitrosourea in hepatic tissues of Sprague Dawley rats

We investigated the protective effect of bee honey and Nigella sativa against methylnitrosourea [MNU] induced oxidative stress, apoptosis and down-regulation of the gap junction protein connexin 43 [Cx43] in hepatic tissues. Our results showed that MNU induced hepatic dysplasia and oxidative stress through decreasing reduced glutathione [GSH] level, decreasing the activities of glutathione reductase [GRase] and superoxide dismutase [SOD], enhancing glutathione peroxidase [GPx] activity and elevating nitric oxide [NO] level in liver tissues as compared to control. Apoptosis, as indicated by significant release of cytochrome c [cyto c] from mitochondria into the cytosol, was observed in MNU injected rats and was positively correlated with the elevation of N0 level. Bee honey and Nigella protected against the previous deleterious changes by significant elevation of GSH level, increasing the activities of GRase and SOD, decreasing the activity of GPx, decreasing NO level and stopping release of cyto c from mitochondria as compared to MNU injected rats. Moreover, down-regulation of Cx43 by MNU was prevented in 50% and 75% of animals that received Nigella alone or both Nigella and bee honey, respectively. These data illustrated the consequences of MNU induced hepatocellular dysplastic changes and oxidative stress and shed the light about the possible sites targeted by bee honey and Nigella in their protective effect against the earlier stages of liver carcinogenesis

Evaluation of some genetic factors influencing the phenotypic severity of beta thalassemia Egyptian patients

The objective of this study was to identify the influence of some genetic factors on the severity of Beta thalassemia. The study included 62 patients [27 Beta thalassemia major and 35 Beta thalassemia intermedia]. The patients were classified as major or intermedia on the basis of clinical examination, age of onset, rate of blood transfusion and hematological data. The search for mutations was done using polymerase chain reaction followed by reverse dot-biot technique. Severe mutations [B0] were found to cause Beta thalassemia major while milder mutations [B++] were noticed in Beta thalassemia intermedia patients. Amplification of a globin gene was successful in 57 Beta thalassemia patients. Alpha globin gene deletion was detected in 7% of the patients with a frequency of 9.4% for Beta thalassemia intermedia and 4% for the major patients. Moreover, the triple alpha arrangement [alpha-alpha-alpha 3, 7] was present in only one Beta thalassemia major Patient. The an1 polymorphism [C-T] was found in 4.8% of the Patients with a frequency of 5.7% for B thalassemia intermedia and 3.7% for the major patients. The mild phenotype of Beta thalassemia intermedia patients could be explained mainly by presence of mild B thalassemia mutations, coinheritance of a globin gene deletion and/or G gamma Xmn1 polymorphism. The search for additional genetic defects in a globin gene or other modifying factors is recommended for unexplained mild Beta thalassemia cases