D-galactose induced changes in enzymatic antioxidant status in rats of different ages.

Considering the preexisting influence of the process of natural aging on antioxidant enzymes activity and the level of lipid peroxidation, the age of the rats at which D-galactose (D-gal) treatment is started could strongly impact the development of D-gal induced senescence. To evaluate this, we subjected 1, 3 and 15 months old rats to D-gal treatment in parallel with having appropriate placebos (0.9 % saline). Our results showed elevated glutathione peroxidase (GPx) activity and no significant changes in superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) activity or malondialdehyde (MDA) levels in relation to natural aging. In mature and aged senescent livers we observed positive correlation between increased ratio R=SOD/(GPx+CAT) and increased MDA concentration. MDA levels seemed to correlate positively with the age of the animals at which D-gal treatment had started. In the case of 3 and 15 months old rats there was D-gal induced decrease in SOD and GR activity, but this effect of the treatment was not observed in 1 month old rats. Our results imply that the changes in the antioxidant enzyme activities are not only under the influence of the D-gal overload, but also depend on the developmental stage of the rats. According to our results, with regard to enzymatic antioxidant capacity and the level of lipid peroxidation, the best age for induction of senescence is somewhere after the third month.

Influence of chronic chromium exposition on the processes of lipid peroxidation inflammation and platelet activation in rats.

The aim of this study was to investigate the effect of chronic treatment with chromium hexavalent (Cr VI) on the platelet activation, inflammation and lipid peroxidation in rats. Thirty male Wistar rats weighing 251 ± 18 g were randomly assigned to one control and one Cr-exposed group. 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)), interleukin 1ß (IL-1ß), tumor necrosis factor alpha (TNF-alpha) and creatinine (Crt), were measured in plasma, while 11-dehydro thromboxane B2 (11-dehydro-TXB2) in plasma andurine. Plasma levels of IL-1ß, TNF-alpha, 8-iso-PGF(2α) and Crt were significantly increased in the Cr (VI)-treated in comparison to the control group. Also, in the urine of Cr (VI)-treated rats, 11-dehydro-TXB2 was significantly increased in comparison to control rats. From the obtained data it is evident that chronic treatment with Cr (VI), accelerates arachidonic acid peroxidation in rats, which peroxidation further probably induces enhanced 11-dehydro-TXB2 excretion rate.

Age and heat exposure-dependent changes in antioxidant enzymes activities in rat's liver and brain mitochondria: role of alpha-tocopherol.

To investigate the role of mitochondrial antioxidant capacity during increased susceptibility to heat accompanied by the aging, young and aged Wistar rats were exposed on heat for 60 min. After heat exposure, hepatic and brain mitochondria were isolated. Our results revealed changes in antioxidant enzyme activities in liver and brain mitochondria from young and to a greater extent in aged rats. Our measurements of MnSOD, GPx and GR activity indicate greater reactive oxygen species production from the mitochondria of aged heat exposed in comparison to young heat exposed rats. Also in the aged rats, the effect of alpha-tocopherol treatment in the prevention of oxidative stress occurred as a result of heat exposure, is less pronounced. Taken together, our data suggest that mitochondria in aged rats are more vulnerable and less able to prevent oxidative changes that occur in response to acute heat exposure.

Diagnostic validation of ovine and caprine brucellosis using serum- and milk-ELISA.

AIM: To introduce and validate the new method of diagnosing ovine and caprine brucellosis in a rapid, accurate and inexpensive manner by using i-ELISA (serum/milk) technique. METHODS: Serum and milk samples from brucella RB and CFT negative (n=881) and positive (n=755) animals were used. Standardization of tests was through the Bommeli ELISA-BESW (Brucella Bang) standard and our Institute's (MKD) working standards (positive serum and milk based on B. melitensis antigen). RESULTS: Validation of serum/milk ELISA for detecting ovine and caprine brucellosis was completed. The specificity obtained for the serum ELISA was 99.0% for the Bommeli system (at cut-off of 30% of positivity--PP) and 99.4% for the MKD system (at cut-off 15% PP). The sensitivities of serum ELISAs at the same cut-off were 98.5% for the Bommeli and 96.6% for the MKD test. Parallel milk samples from the same animals showed a specificity of 99.5% in the Bommeli system (at cut-of 30% PP) and 99.8% in the MKD system (at cut-off 25% PP). The sensitivity of the milk ELISAs were 94.6% for the Bommeli test and 95.6% for the MKD test. CONCLUSION: The Bommeli ELISA and MKD ELISA were successfully standardized and validated as confirmatory tests for the diagnosis of B. melitensis in sheep and goat samples (milk/sera). Using our Institute's milk standard, we confirmed successful screening of brucellosis in pooled milk samples from 100 sheep and 100 goats.

Brucellosis control in small ruminants in the Republic of Macedonia.

AIM: To present the main goals and activities of the strategy for control of brucellosis caused by B. melitensis in sheep and goats in the Republic of Macedonia. METHODS: Relevant documents and reports from the Veterinary Directorate were used to present the approaches for control of the disease in small ruminants in R. Macedonia. The new strategy for control and eradication of brucellosis started its implementation in 2008 with combination of measures for test and slaughter of the sero-positive sheep and goats, mass vaccination and vaccination of young replacements. RESULTS: In 2008, a total of 596,213 animals have been tested in 5,820 flocks out of which 16,853 (2.8%) had Brucella positive results in 636 (10.9%) flocks. In 2009, a total of 543,011 sheep and goats had been tested in 5,507 flocks out of which 9,606 (1.8%) animals showed positive results in 666 (12.1%) flocks. While the number of positive flocks does not indicate great improvement, the individual number of Brucella-positive animals has decreased dramatically. The number of human cases in 2008 and 2009 were 490 and 287 respectively. Direct savings only from compensation to farmers for slaughtered animals for 2008 and 2009 are estimated to be more than 100,000,000 denars (~1.6 million Euro). CONCLUSION: RESULTS from 2009 have been evaluated and foreseen amendments will allow that the country will be systematically divided in a more detailed epidemiological fashion, i.e. division of the country into epidemiological units based on the disease status and accepted risk and implementation of appropriate measures therein.