Effect of reactive oxygen species on the erythrocyte calcium-pump function in protein-energy malnutrition

1992 ◽  
Vol 12 (6) ◽  
pp. 433-443 ◽  
Author(s):  
W. G. Okunade ◽  
O. O. Olorunsogo
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Reactive Oxygen ◽  
Heme Iron ◽  
Calcium Pump ◽  
Oxygen Species ◽  
Non Heme Iron ◽  
Normal Individuals

The presence of detectagle amounts of non-heme iron in erythrocyte ghost membranes have been postulated to lead to the initiation of membrane lipid peroxidation and the attendant perturbation of membrane functions. We have investigated the presence of non-heme iron and endogenous products of lipid peroxidation in erythrocyte membranes of normal and kwashiorkor (KWA) subjects and assessed the susceptibility of the membranes to exogenously generated reactive oxygen species. The modulation of the basal and calmodulin-stimulated calcium-pumping activity of these membranes by reactive oxygen species was also assessed. The results show the presence of significant amounts of non-heme iron and endogenous free radical reaction products in the red cell membranes of KWA subjects compared with that of normal children. Estimation of the extent of lipid peroxidation in the presence of exogenously generated reactive oxygen species further revealed that erythrocyte ghost membranes of KWA subjects are more susceptible to oxidative stress than those of normal individuals. Although both the basal and calmodulin-stimulated activities of the membrane-bound Ca2+-pump enzyme in normal and KWA subjects were inhibited by oxygen-free radicals, the erythrocyte enzyme in KWA subjects showed higher susceptibility to inhibition by oxygen free radicals than that of normal individuals. We propose that the reduced erythrocyte calcium-pump function in KWA is not unconnected with excessive generation of reactive oxygen species.

EFFECT OF REACTIVE OXYGEN SPECIES ON THE ERYTHROCYTE CALCIUM-PUMP FUNCTION IN PROTEIN-ENERGY MALNUTRITION

PEDIATRICS ◽  
1995 ◽  
Vol 95 (6) ◽  
pp. 874-874
Author(s):  
W. G. Okunade ◽  
O. O. Olorunsogo
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Oxygen Radicals ◽  
Reactive Oxygen ◽  
Normal Subjects ◽  
Calcium Pump ◽  
Free Oxygen Radicals ◽  
Oxygen Species ◽  
Free Oxygen ◽  
Pump Function

Marasmus is felt to result from a diet that is fairly equally deficient in protein and in calories. In contrast, kwashiorkor is usually explained as being caused by a diet deficient more in proteins than in calories. This explanation for kwashiorkor has been questioned by Golden and Ramdath,1 who suggested that the pathogenesis could be better explained by an imbalance between the quantity of free oxygen radicals and scavengers of those free oxygen radicals. The authors of this paper took anemia as one of the usual clinical features of kwashiorkor and attempted to verify this hypothesis by measuring "the presence of non-heme iron and endogenous products of lipid peroxidation in the erythrocyte membranes of normal and kwashiorkor subjects and assessed the susceptibility of the membranes to exogenously generated reactive oxygen species." The extent of lipid peroxidation in the erythrocytes of kwashiorkor subjects was three times that found in erythrocytes of normal subjects. The erythrocytes from kwashiorkor subjects were much more susceptible to oxidative stress than were the erythrocytes from normal subjects and the oxygen free radicals reduced the erythrocyte calcium-pump function in kwashiorkor subjects to a greater extent than in normal subjects. These findings lend support for the hypothesis of the pathogenesis of kwashiorkor proposed by Golden and Ramdath.

315 REACTIVE OXYGEN SPECIES AND OXIDATIVE STRESS IN CANINE SEMEN FRACTIONS

2010 ◽  
Vol 22 (1) ◽  
pp. 313
Author(s):  
C. F. Lucio ◽  
M. Nichi ◽  
F. M. Regazzi ◽  
T. F. Rück ◽  
L. C. G. Silva ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Free Radicals ◽  
Sperm Motility ◽  
Seminal Plasma ◽  
Pearson Correlation ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Low Concentrations ◽  
Viable Sperm

Reactive oxygen species (ROS) are physiologically produced by spermatozoa and leukocytes present in the seminal plasma. In low concentrations, ROS play an important role in sperm function because they are required for sperm fertilizing capacity, mainly during sperm capacitation and hyperactivation (Saleh RA and Agarwal A 2002 J. Androl. 23, 737-752). However, an imbalance between the formation of free radicals and the capacity for defense of the antioxidant mechanisms may lead to cell damage (Rover Jr L et al. 2001 Química Nova 24, 112-119). Spermatozoa are sensitive to lipid peroxidation due to its high content of polyunsaturated fatty acids and low concentrations of protective enzymes (Sharma RK and Agarwa LA 1996 Urology 48, 835-850). The aims of the present study were to compare ROS content among the 3 fractions of canine semen and to correlate these values with sperm variables. Semen samples were collected from 15 healthy dogs of distinct breeds aged 2 to 6 years. Sperm analysis was performed through motility, forward progressive velocity, morphology, and the percentage of viable sperm with the use of the eosin/nigrosin stain. The determination of thiobarbituric acid reactive substances (TBARS) was used to estimate the degree of lipid peroxidation in each sperm fraction. Values were compared using ANOVA and Tukey’s test for multiple comparisons at a significance level of 5%. Pearson correlation was used to calculate the relationship between sperm variables in the second fraction. Sperm motility, velocity, and percentage of viable sperm were within the normal range for canine semen: 84±2%, 3.4±0.1%, and 83 ± 2%, respectively. The sperm-rich fraction presented statistically higher concentrations of TBARS (1474.19 ± 245.78 ng mL-1) compared to the first and third fractions (579.41 ± 171.23 and 399.62 ± 58.08 ng mL-1, respectively; P < 0.05), indicating that spermatozoa and epididymal secretions are the main source of free radicals. No statistical correlation among TBARS and sperm motility and velocity were verified. However, a positive correlation was observed between the percentage of sperm proximal droplets and TBARS (r = 0.44, P = 0.7). This result suggests that a high incidence of sperm proximal droplets can enhance ROS formation in seminal plasma. Hence, canine sperm presenting delayed maturation in the epididymes produce higher concentrations of free radicals. In fact, sperm production of ROS occurs mainly by abnormal cells, especially the ones containing cytoplasm residues (Gomez E et al. 1998 Int. J. Androl. 21, 81-94). However, no protective effect of the sperm distal droplets was verified in canine semen as observed elsewhere for the bovine spermatozoa (Nichi M et al. 2007 Theriogenology 67, 334-340). In conclusion, spermatozoa and epididymal fluids are the primordial source of free radicals in canine seminal plasma, mainly when sperm proximal droplets are present.

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

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