Biomedical subjects

Iva Bousová

Publications and source records attributed to Iva Bousová.

3 recordsLinked to original sources

PubMed2006

Oxidative stress parameters in different systemic rheumatic diseases.

The involvement of oxidative stress in the pathogenesis of rheumatic disorders, such as systemic sclerosis (SSc) and chronic polyarthritides, has been suggested yet not thoroughly verified experimentally. We analysed 4 plasmatic parameters of oxidative stress in patients with SSc (n = 17), psoriatic arthritis (PsA) (n = 10) and rheumatoid arthritis (RA) (n = 9) compared with healthy subjects (n = 22). The biomarkers were: total antioxidant capacity (TAC) measured by ferric reducing antioxidant power (FRAP) method, hydroperoxides determined by ferrous ion oxidation in presence of xylenol orange (FOX) method and sulfhydryl and carbonyl groups assessed by spectrophotometric assays. The results showed significantly increased hydroperoxides in SSc, PsA and RA (3.97 +/- 2.25, 4.87 +/- 2.18 and 5.13 +/- 2.36 micromol L(-1), respectively) compared with the control group (2.31 +/- 1.40 micromol L(-1); P < 0.05). Sulfhydryls were significantly lower in SSc (0.466 +/- 0.081 mmol L(-1)), PsA (0.477 +/- 0.059 mmol L(-1)) and RA (0.439 +/- 0.065 mmol L(-1)) compared with the control group (0.547 +/- 0.066 mmol L(-1); P < 0.05). TAC in all three diseases showed no difference in comparison with controls. Carbonyls were significantly higher in RA than in the control group (32.1 +/- 42 vs 2.21 +/- 1.0 nmol (mg protein)(-1); P < 0.05). The obtained data indicate augmented free radical-mediated injury in these rheumatic diseases and suggest a role for the use of antioxidants in prevention and treatment of these pathologies.

Adult↗

PubMed2005

Glycation-induced inactivation of aspartate aminotransferase, effect of uric acid.

Glycation is common posttranslational modification of proteins impairing their function, which occurs during diabetes mellitus and aging. Beside extracellular glycation of long-lived proteins, intracellular modifications of short-lived proteins by more reactive sugars like fructose are possible. The process includes free oxygen radicals (glycoxidation). In an attempt to reduce glycoxidation and formation of advanced glycation products (AGE), influence of 0.2-1.2 mM uric acid as endogenous antioxidant on glycoxidation of purified pig heart aspartate aminotransferase (AST) by 50 mM and 500 mM D-fructose in vitro was studied. Uric acid at 1.2 mM concentration reduced AST activity decrease and formation of total AGE products caused by incubation in vitro of the enzyme with sugar up to 25 days at 37 degrees C. The results thus support the hypothesis that uric acid has beneficial effects in controlling protein glycoxidation. The in vitro system AST-fructose proved to be a useful tool for investigation of glycation process.

Aspartate Aminotransferases↗

PubMed2004

Determination of quality of pyridoxal-5'-phosphate enzyme preparations by spectroscopic methods.

The present study evaluates purified aspartate transaminase (AST, EC 2.6.1.1) preparations from three commercial sources. The enzyme molecule contains pyridoxal-5'-phosphate coenzyme (PLP), which provides AST characteristic absorption spectra in the wavelength range of 300-500 nm. The coenzyme bound in the active site also shows circular dichroism (CD) spectra in the same range. Besides, AST like other proteins may be modified in vitro or in vivo by reactions with other molecules, e.g. reactive sugars, and may form fluorescent products (advanced glycation end products, AGE). Spectroscopic methods were used to assess the quality of AST preparations from three different sources, Serva, Roche, and Sigma. Absorption spectra showed that the peak 360 nm characteristic of the active PLP form of AST prevailed in the Serva and Sigma preparations, while 330 nm was the major peak in the Roche preparation. CD spectra demonstrated the major maximum at 360 nm in the Serva and Roche samples, thus suggesting the predominance of the active PLP form in both preparations. The Sigma sample showed a CD profile less characteristic of AST. Fluorescence measurements revealed formation of AGE in the case of the Roche preparation, while fluorescence of the other two preparations was low. In general, the Serva sample presented the most convenient properties of purified AST among the preparations tested. The results will be used for the selection of a commercial enzyme preparation applicable in our future spectroscopic studies of glycation of AST as a model protein and in our research of the influence of antioxidants on this process.

Animals↗