Ayla Özcan

Subclinical mastitis causes alterations in nitric oxide, total oxidant and antioxidant capacity in cow milk.

The aim of this study was to investigate total antioxidant (TAC), and oxidant capacity (TOC) and nitric oxide (NO) levels in milk of cows with subclinical mastitis. Brown Swiss and Holstein breed cows were screened with California Mastitis Test (CMT) to determine mammary glands with subclinical mastitis. Moreover, somatic cell counts (SCC) were determined electronically in all milk samples. Mammary quarters were classified as healthy (n=25) or subclinical mastitis (n=35) based on CMT scores and somatic cell count (SCC: < or =200,000/ml or >200,000/ml) in milk. Nitric oxide, TOC and SCC levels were significantly higher (p<0.001, p<0.005 and p<0.001, respectively) in milk from mammary quarters with subclinical mastitis compared to those from healthy mammary quarters. In conclusion, subclinical mastitis results in higher NO concentrations, TOC and SCC, and NO and TOC were positively correlated with SCC. Moreover, alterations in NO levels and TOC in milk could be used as an alternative diagnostic tool to screen for subclinical mastitis.

Oleuropein ameliorates arsenic induced oxidative stress in mice.

The objective of this study is to investigate the potential preventive effect of oleuropein in an experimental arsenic toxicity in mice. For this purpose, mice were exposed to 5mg/kg/day sodium arsenite (NaAsO2) in drinking water and treated with 30mg/kg/day oleuropein for 15 days. At the end of the experiment, animals were sacrificed and selected organs were processed for biochemical and histopahtological investigations. Blood, liver, kidney and brain malondialdehyde (MDA) and nitric oxide (NO) levels were determined by colorimetric methods. Protein carbonyl content is measured by a commercial kit. Liver morphology and immunoreactivity for inducible NOS (iNOS) and endothelial NOS (eNOS) was evaluated microscopically. Level of NO was determined to decrease in blood and tissues whereas MDA increased in arsenic given mice. Tissue protein carbonyl content also increased in this group. Immunoreactivity for iNOS and eNOS was noted to increase with arsenic treatment. Oleuropein treatment had significant effects in normalizing the MDA and NO levels as well as protein carbonyl content. Immunohistochemical staining also showed reduction of the expression of iNOS and eNOS in liver. The results indicate that oleuropein ameliorates oxidative tissue damage by scavenging free radicals.

Biochemistry of Reactive Oxygen and Nitrogen Species

Reactive species or free radicals include reactive oxygen and nitrogen species that are called reactive oxygen nitrogen species. Reactive oxygen species are formed as a natural by-product of the normal metabolism of oxygen and have significant roles in cell signaling and homeostasis. The reactive oxygen species are generated as a byproduct of biochemical reactions, in mitochondria, peroxisomes, cytochrome P450, and other cellular components. When oxygen homeostasis is not maintained, oxidative stress is increased in the cellular environment. Superoxide, hydrogen peroxide and hydroxyl radicals are normal metabolic by-products which are generated continuously by the mitochondria in growing cells. Microsomal cyto‐ chrome P450 enzymes, flavoprotein oxidases and peroxisomal enzymes are other significant intracellular sources of reactive oxygen species.

Reduced Glutathione, Malondialdehyde, β-Carotene and Retinol Levels in Lambs Fed with Various Amounts of Oak Leaves

Çal şmada, farkl miktarlarda tüketilen meşe yaprağ n n (Quercus hartwissiana), polietilen glikol (PEG) varl ğ nda ya da yokluğunda, redükte glutatyon (GSH), malondialdehit (MDA), β-karoten ve retinol gibi oksidan/antioksidan sistemde rolü olan parametrelere etkisinin olup olmad ğ n n araşt r lmas amaçlanm şt r. Çal şmada materyal olarak canl ağ rl k ortalamas 33.0±0.7 kg olan 42 kuzu kullan ld . Her grupta 6 kuzu olacak şekilde 7 gruba ayr ld . Deneme boyunca bireysel kafeslerinde bar nd r lan hayvanlara kuru madde baz nda 272 g konsantre yem ve değişik miktarlarda kuru ot verildi. Grup 1: Standart rasyon (Kontrol), Grup 2: 185 g meşe yaprağ ve 0 g PEG; Grup 3: 185 g meşe yaprağ +10 g PEG; Grup 4: 185 g meşe yaprağ + 20 g PEG; Grup 5: 370 g meşe yaprağ ; Grup 6: 370 g meşe yaprağ + 20 g PEG; Grup 7: 370 meşe yaprağ + 40 g PEG verilerek beslendi. Tüm hayvanlardan denemeye başlan ld ğ gün (kontrol), 30. ve 60. günlerinde kan numuneleri topland . Tam kanda GSH, plazmada MDA, β-karoten ve retinol düzeyleri kolorimetrik olarak saptand . Kaba yem kaynağ olarak kat lan meşe yaprağ n n PEG varl ğ nda ya da yokluğunda lipid peroksidasyonun belirteci olan MDA, antioksidan özelliğe sahip GSH, retinol ve β-karoten düzeylerinde istatistik olarak önemli bir farka neden olmad ğ tespit edildi. Gruplar günlere göre mukayese edildiğinde sadece Grup 4’teki 60. gün MDA düzeyinin diğerlerine göre istatistik olarak düşük (P<0.05) olduğu bulundu. Bu sonuçlara bak larak meşe yaprağ n n antioksidatif parametreler yönünden olumlu ya da olumsuz bir etkisinin olmad ğ sonucuna var ld .