No abstract

Oxidative stress may produce high level of reactive oxygen species (ROS) following cell exposure to endogenous and exogenous factors. Recent experiments implicate oxidative stress as playing an essential role in cytotoxicity of many materials. The aim of this study was to measure intracellular malondialdehyde (MDA), advanced oxidation protein product (AOPP) levels, and superoxide dismutase (SOD) activities of L929 fibroblasts cultured on PDLLA, polyethylene glycol (PEG), or ethylenediamine (EDA) grafted PDLLA by plasma polymerization method. Cell proliferation on these scaffolds was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The study showed that MDA, AOPP levels, and SOD activities in L929 fibroblast cells cultured on all scaffolds were significantly different compared to the control group and each other. The highest MDA (0.42 ± 0.76 nmol/mg protein), AOPP (14.99 ± 4.67 nmol/mg protein) levels, and SOD activities (7.49 ± 3.74 U/mg protein) were observed in cells cultured on non-modified scaffolds; meanwhile, the most cell proliferation was obtained in EDA-modified scaffolds (MDA 0.15 ± 0.14 nmol/mg protein, AOPP 13.12 ± 3.86 nmol/mg protein, SOD 4.82 ± 2.64 U/mg protein). According to our finding, EDA- or PEG-modified scaffolds are potentially useful as suitable biomaterials in tissue engineering.

No abstract

INTRODUCTIONDementia is a slow-onset clinical condition characterized by cognitive dysfunction, memory impairment, behavioral and personality changes, and poor judgment which later progresses to severe.1,2 The prevalence of dementia rises markedly with age, the rate is about 10% in people between 65-70 years and 20-48% in over 70 years. Alzheimer dementia (AD) and vascular dementia are the two most common types of dementia. AD accounts for 60% of all dementias. Various studies reported that vitamin B 12 (Vit B 12 ) levels were lower in individuals with dementia than in those without. 4,5 Reports indicated that, cerebral oxidative damage was due to increased oxidation of Vit B 12 generated by methylene synthase activity and the resulting disruption of homocysteine metabolism in AD.6,7 Current data is not adequate to elucidate the exact correlation between the pathogenesis of AD and Vit B 12.8,9 However low levels of Vit B 12 were reported in patients with dementia and significant improvement in cognitive functions were observed by Vit B 12 replacement therapy. 10Vit B 12 deficiency in rats and humans was associated with a decrease in epidermal growth factor (EGF) levels and an increase in tumor necrosis factor alpha (TNF-α). 11These results suggest a role for EGF and TNF- in the neuropathologic mechanisms in dementia patients. Vit B 12 is a regulator of the balance between TNF-α and EGF in the central nervous system. 12 ABSTRACT Background: It was previously reported that vitamin B 12 (Vit B 12 ) has the regulatory effects on epidermal growth factor (EGF) and tumor necrosis factor alpha (TNF-α). The role of Vit B 12 , EGF and TNF-α in the pathogenesis of alzheimer dementia has not been elucidated yet. In this study the plasma Vit B 12 , EGF and TNF-α level were examined in individuals, between 65-99 years old with and without alzheimer dementia (AD). Methods: The study group comprised 47 patients with AD and 38 cases without dementia. EGF and TNF-α were analyzed by ELISA, and Vit B 12 was analyzed by chemiluminescence method. Results: Vit B 12 and EGF levels were significantly lower (p<0.0001), whereas TNF-α levels were significantly higher (p<0.0001) in the AD group in comparison to those without AD. Conclusions: Our results suggest that Vit B 12 , EGF and TNF-α may have a role in the pathophysiology of AD.

Abstract:The role of increased oxidative stress in the development of oxidative protein damage in aging have been reported. There is an important role of oxidative stress on development of dementia. Advanced oxidation protein products (AOPPs) are novel markers of oxidative stress. The aim of this study was to compare AOPP levels in healthy aged person and aged person with dementia. AOPP levels were in the control group 83.36 ± 35.51 µmol/L, and 178.78 ± 110.50 µmol/L in the group with dementia. This elevation in the group with dementia was statistically significant (p<0.05). AOPP might be a useful novel indicator of oxidative stress in dementia.