High sensitivity to autoxidation in neonatal calf erythrocytes: possible mechanism of accelerated cell aging

Corpuscular oxidation in newborn crossbred calves naturally infected with Theileria annulata

Erythrocytic lipid peroxidation has been implicated as a cause of anemia in Theileria annulata infection in cattle. The present study aimed to evaluate oxidative damage of membrane lipids and proteins in addition to hemoglobin (Hb) as three criterions of erythrocyte oxidation and their relation to erythrocyte deformability and anemia of newborn crossbred calves (Friesian × Egyptian Balady breed) naturally infected with T. annulata. Twenty-five T. annulata-infected calves (aged 20-30 days) along with 15 age matched healthy controls were used. Percentage of parasitemia varied from 12% to 63% (34.76 ± 3.05%). In comparison to controls, infected calves showed increased levels (P<0.001) of lipid peroxidation (malondialdehyde; MDA, 52%) and protein oxidation (protein carbonyls; PCs, 132%) in erythrocyte membrane as well as increased values of Hb oxidation (methemoglobin; MetHb, 186%), corpuscular osmotic fragility (15.1%) and hemolysis (free Hb; 195.5%). Parasitemia was positively correlated with MDA (r=0.41, P=0.039), PCs (r=0.45, P=0.023) and MetHb (r=0.40, P=0.042). Also, percent of erythrocytic deformability (echinocytosis) was positively correlated with MDA (r=0.49, P=0.013) and PCs (r=0.63, P<0.001). On the other hand, erythrocytic packed cell volume was negatively correlated with MDA (r=-0.44, P=0.028), PCs (r=-0.72, P<0.001) and MetHb (r=-0.42, P=0.037). In conclusion, T. annulata infection is associated with a parasitic burden-dependant oxidative damage to the erythrocyte membrane protein and lipid contents in addition to Hb. This oxidative damage is linked to the morphological changes of the erythrocyte and may act as mechanisms contribute to pathogenesis of anemia in T. annulata infection in newborn calves.

Sulfation of a polysaccharide produced by a marine filamentous fungus Phoma herbarum YS4108 alters its antioxidant properties in vitro

Free radicals and other reactive oxygen species (ROS) are generated by all aerobic cells and are widely believed to play a significant role in aging as well as a number of degenerative or pathological diseases. This study compared the free radical-scavenging properties and antioxidant activity of YCP, a polysaccharide from the mycelium of a marine filamentous fungus Phoma herbarum YS 4108 and its two chemically sulfated derivatives YCP-S1 and YCP-S2. Sulfation, which masks hydroxyl groups of YCP polysaccharide molecule, could introduce new antioxidant activity, such as superoxide and hydroxyl radicals scavenging activity, metal chelating action, lipid peroxidation and linoleic acid oxidation inhibition capability. Furthermore, sulfated YCP was more potent than YCP at protecting erythrocytes against oxidative damage hemolysis. The current data suggest for the first time that sulfation of polysaccharide significantly increases its antioxidant activity and the chemical modification of polysaccharides may allow the preparation of derivatives with new properties and a variety of applications.

Influence of plasma total antioxidant ability on lipid and protein oxidation products in plasma and erythrocyte ghost obtained from developing and adult rats pretreated with two vitamin K formulations

Ferric reducing ability of plasma (FRAP), as an index of total antioxidant capacity of plasma was found to be enhanced significantly (p < 0.05) in suckling rats pretreated either with vitamin K1 (28, 56 or 84 mg/kg/3 days) or menadione (vitamin K3) at a dose of 15 mg/kg b.w./3 days. The effect of vitamin K1 on FRAP was dose-dependent and it was inversely related to the formation of lipid peroxidation products in plasma as judged by thiobarbituric acid reacting substances (TBARS). Lack of influence of the drugs on FRAP in adults was corroborated with elevation in the levels of plasma TBARS. Possible role of FRAP on the rate of lipid peroxidation and protein oxidation (protein carbonyls) on erythrocyte membrane was also investigated following isolation of erythrocyte ghost from control and treated rats. Vitamin K1 as well as menadione failed to change the levels of protein carbonyls in erythrocyte ghost obtained from both the age groups. Analysis of major erythrocyte membrane proteins, using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) substantiated these results. In spite of higher antioxidant capacity of plasma and erythrocytes obtained from young rats, the rate of lipid peroxidation in erythrocyte ghost preparation was also high in this age group (p < 0.05). These results suggest that the drug-related induction in FRAP occurs only in immature animals as a part of protective mechanism against lipid peroxidation products generated in plasma.

Experimental gerontology in Hungary

Gerontological research has some past and sporadically also some highlights in Hungary, but its present state can be easily deduced from the following data. During the last 12 years and more, well over 10,000 Hungarian scientific papers have been published in well-recognized national or international journals. Altogether approximately 1% of them have been classified as gerontological publications from Hungary. This low figure shows that gerontology has low priority and--unfortunately low support--in Hungary. This statement does not intend to downgrade Hungarian gerontologists, however points out that the Hungarian trends are not far from those of European or world wide interest in aging. Despite the recognition that we have to accept the inevitable fact that industrial societies will have (they already have) an aging population with all the social and medical problems arising, the focus of interest is wide from this significant and interesting (sub)population, which is neglected (sometimes even despised); yet everybody is absolutely eager to join this club. The average of the Hungarian research achievements and publication activities are among the better European achievements. There are some highlights and new trends even initiated by some outstanding Hungarian scientists, yet the overall weight of gerontology research is still an orphan in the Hungarian scientific life. We deal in this short and far from complete summary almost exclusively with experimental gerontology. We have to apologize if we have not included everybody, who also contributed even significantly to this field because the time for the preparation of this overview was short.