scholarly journals Positive correlation of pigment epithelium-derived factor and total antioxidant capacity in aqueous humour of patients with uveitis and proliferative diabetic retinopathy

2007 ◽  
Vol 91 (9) ◽  
pp. 1133-1134 ◽  
Author(s):  
Y. Yoshida ◽  
S.-i. Yamagishi ◽  
T. Matsui ◽  
K. Nakamura ◽  
T. Imaizumi ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Antioxidant Capacity ◽  
Proliferative Diabetic Retinopathy ◽  
Total Antioxidant Capacity ◽  
Aqueous Humour ◽  
Pigment Epithelium ◽  
Positive Correlation ◽  
Pigment Epithelium Derived Factor ◽  
Total Antioxidant

Biochemical characterization of enzymatic browning in selected apple genotypes

2007 ◽  
Vol 87 (5) ◽  
pp. 1067-1074 ◽  
Author(s):  
A. P. K. Joshi ◽  
H. P. V. Rupasinghe ◽  
N. L. Pitts ◽  
S. Khanizadeh
Keyword(s):  
Vitamin C ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Enzymatic Browning ◽  
Strong Positive Correlation ◽  
Antioxidant Power ◽  
Whiteness Index ◽  
Positive Correlation ◽  
Polyphenol Oxidases ◽  
Total Antioxidant

Enzymatic browning in apples (Malus × domestica Borkh.) caused by polyphenol oxidases (PPO) is the major factor responsible for the deterioration of quality in processed apple products such as juice, fresh-cut slices, and chips. Selected apple genotypes with a range of low post-cut enzymatic browning were investigated to understand the biochemical mechanisms leading to enzymatic browning. Post-cut enzymatic browning, polyphenolic profiles using LC-MS/MS, PPO activity, vitamin C, total antioxidant capacity using the Ferric Reducing Antioxidant Power (FRAP) and the Oxygen Radical Absorbance Capacity (ORAC), and elemental composition were determined in two recently released cultivars [Eden™(also known as SJCA38R6A74) and SuperMac], and one new advanced line (SJCA16) and compared with two commercial cultivars (Empire and Cortland). Eden™ exhibited the least post-cut enzymatic browning as estimated by Whiteness Index. SJCA16 possessed a characteristic yellowish flesh color. Whiteness Index (WI) values were inversely related to chlorogenic acid, catechin and epicatechin contents present in apple slices. Vitamin C content showed a strong positive correlation with WI. Among the mineral elements, the content of copper had a strong positive correlation with PPO activity. Key words: Apple genotypes, enzymatic browning, polyphenoloxidase, polyphenolics, Whiteness Index, total antioxidant capacity

scholarly journals The Association between Diabetic Retinopathy and Levels of Ischemia-Modified Albumin, Total Thiol, Total Antioxidant Capacity, and Total Oxidative Stress in Serum and Aqueous Humor

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kadir Kirboga ◽  
Ayse V. Ozec ◽  
Mustafa Kosker ◽  
Ayhan Dursun ◽  
Mustafa I. Toker ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Retinopathy ◽  
Antioxidant Capacity ◽  
Aqueous Humor ◽  
Total Antioxidant Capacity ◽  
Control Group ◽  
Total Thiol ◽  
Median Serum ◽  
Total Antioxidant ◽  
Total Oxidative Stress

Purpose. To investigate the oxidant and antioxidant status of patients with type 2 diabetes mellitus and nonproliferative diabetic retinopathy (DRP).Methods. Forty-four patients who had cataract surgery were enrolled in the study. We included 22 patients with DRP in one group and 22 patients in the control group. Samples of aqueous humor and serum were taken from all patients. Serum and aqueous ischemia-modified albumin (IMA), total thiol, total antioxidant capacity (TAC), and total oxidative stress (TOS) levels were compared in two groups.Results. Median serum IMA levels were 44.80 absorbance units in the DRP group and 40.15 absorbance units in the control group (P=0.031). Median serum total thiol levels in the DRP group were significantly less than those in the control group (3051.13 and 3910.12, resp.,P=0.004). Mean TOS levels in the serum were 2.93 ± 0.19 in the DRP group and 2.61 ± 0.26 in the control group (P=0.039). The differences in mean total thiol, TAC, and TOS levels in the aqueous humor and mean TAC levels in the serum were not statistically significant.Conclusion. IMA, total thiol, and TOS levels in the serum might be useful markers in monitoring the risk of DRP development.

scholarly journals Metabolic Memory Phenomenon and Accumulation of Peroxynitrite in Retinal Capillaries

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Renu A. Kowluru ◽  
Mamta Kanwar ◽  
Alexander Kennedy
Keyword(s):  
Diabetic Retinopathy ◽  
Glycemic Control ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Metabolic Memory ◽  
Retinal Microvasculature ◽  
Total Antioxidant ◽  
Acellular Capillaries ◽  
Mnsod Activity ◽  
Retinal Capillaries

Aim. Diabetic retinopathy resists reversal after good glycemic control (GC) is reinitiated, and preexisting damage at the time of intervention is considered as the major factor in determining the outcome of the GC. This study is to investigate the role of peroxynitrite accumulation in the retinal capillaries in the failure of retinopathy to reverse after reestablishment of GC, and to determine the effect of this reversal on the activity of the enzyme responsible for scavenging mitochondrial superoxide, MnSOD.Methods. In streptozotocin-diabetic rats, 6 months of poor glycemic control (PC, glycated hemoglobin,GHb>12.0%) was followed by 6 additional months of GC (GHb about 6%). The trypsin-digested retinal microvessels were prepared for immunostaining of nitrotyrosine (a measure of peroxynitrite) and for counting the number of acellular capillaries (a measure of histopathology). The retina from the other eye was used to quantify nitrotyrosine concentration, MnSOD activity and the total antioxidant capacity.Results. Reversal of hyperglycemia after 6 months of PC had no significant effect on nitrotyrosine concentration in the retina, on the nitrotyrosine-positive retinal capillary cells and on the number of acellular capillaries; the values were similar in PC-GC and PC groups. In the same rats retinal MnSOD activity remained inhibited and the total antioxidant capacity was subnormal 6 months after cessation of PC.Conclusions. Peroxynitrite accumulation in the retinal microvasculature, the site of histopathology, fails to normalize after reversal of hyperglycemia, and superoxide remains inadequately scavenged. This failure of reversal of peroxynitrite accumulation could be, in part, responsible for the resistance of diabetic retinopathy to reverse after termination of PC.

scholarly journals Assessment of Antioxidant Status and Lipid Peroxidation in Pre-Eclampsia

2019 ◽  
pp. 1-9
Author(s):  
Patrick O. Manafa ◽  
Charles C. Onyenekwe ◽  
Anselem C. Igwe ◽  
Nancy A. Mbachu ◽  
George O. Chukwuma ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Positive Correlation ◽  
Spectrophotometric Methods ◽  
Significant Difference ◽  
Total Antioxidant ◽  
Blood Pressures

Aim: To assess the role of antioxidants and lipid peroxidation in the pathogenesis of pre-eclampsia. Study Design: This is a case-control study designed to evaluate the levels of malondialdehyde and total antioxidant capacity with glutathione peroxidase and superoxide dismutase activities in pre-eclamptic. One hundred (100) participants were randomly selected to include fifty pre-eclamptic (test), twenty-five (25) healthy pregnant normotensive women (control A) and twenty-five healthy non-pregnant normotensive women (control B). Place and Duration of Study: This study was carried out at the Holy Rosary Hospital waterside, Onitsha, Anambra state. Nigeria. The study lasted for 13 months. Methodology: One hundred women (50 pre-eclamptic, 25 pregnant normotensives and 25 non-pregnant normotensives) aged 25-40 years were recruited for this study. Blood samples were collected from the participants for the estimation of total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities using spectrophotometric methods. Blood pressures were measured using accosson sphygmomanometer. Data were analysed using analysis of variance and Pearson’s correlation coefficient at p < 0.05. Results: The TAC was significantly higher in the pregnant normotensives (p< 0.05) compared with the pre-eclamptic and non-pregnant normotensives. There was no significant difference in the MDA in pre-eclamptic compared with pregnant normotensives and non-pregnant normotensives (p>0.05). A significant difference was observed in the SOD and GPx activities in the pregnant normotensive and non-pregnant normotensives compared with pre-eclamptic. A positive correlation was observed between the blood pressures (systolic and diastolic) and the activities of TAC, SOD and GPx in pre-eclamptic. Furthermore, a positive correlation was observed between MDA levels and SBP (r = 0.019) while a negative correlation (r = -0.225) existed between MDA and DBP. Conclusion: Diminished ability of antioxidants to scavenge free radicals may affect the onset of pre-eclampsia and therefore possible prognostic tool in its management.

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