ANTIOXIDATIVE PROPERTIES OF GEROPROTECTIVE PEPTIDES

Приведенные в работе результаты исследований об антиоксидантном действии ряда пептидных препаратов, которое наблюдается на различных уровнях, начиная от клеточного до организма в целом, свидетельствуют о важной роли низкомолекулярных пептидов в механизмах регуляции гомеостаза при старении. Антиоксидантные свойства регуляторных пептидов проявляются в экспериментах как на интактных половозрелых животных, так и особенно наглядно при старении или действии экстремальных факторов внешней среды (гипоксия, гипокинезия). Ряд исследуемых пептидов (AEDG, KE) оказывает мембраностабилизирующее действие, препятствуя осмотическому и кислотному гемолизу эритроцитов и снижая уровень содержания внеэритроцитарного гемоглобина и суммарной пероксидазной активности в плазме крови. Показано, что исследуемые пептиды способны оказывать нейропротекторный эффект путем стабилизации активности ферментов (неприлизин, инсулиндеградирующий фермент), играющих важную роль в катаболизме β-амилоида, и препятствовать его накоплению в мозге. Рассматривается участие регуляторных пептидов, обладающих антиоксидантными свойствами, на экспрессию генов, обеспечивающих стабилизацию митохондриальных мембран, функционирование электрон-транспортной цепи и активность антиоксидантных ферментов. The results of studies on the antioxidant effect of a number of peptide drugs, which is manifested at various levels, ranging from cells to the whole body, in adulthood and during aging, under the influence of extreme environmental factors, indicate the important role of low-molecular peptides in the mechanisms of regulating homeostasis during aging. The antioxidant properties of regulatory peptides are shown in experiments both on intact sexually mature animals, and especially clearly during aging or the action of extreme environmental factors (hypoxia, hypokinesia). A number of the studied substances (AEDG, KE) have a membrane-stabilizing effect, preventing osmotic and acid hemolysis of red blood cells and reducing the level of extra-erythrocyte hemoglobin and total peroxidase activity in blood plasma. It is shown that the studied peptides are able to have a neuroprotective effect by stabilizing the activity of enzymes (neprilysin, an insulin degrading enzyme) that play an important role in the catabolism of beta-amyloid, and prevent its accumulation in concentrations toxic to cells. The involvement of regulatory peptides with antioxidant properties on the expression of genes that ensure the stabilization of mitochondrial membranes, the functioning of the electron transport chain and the activity of antioxidant enzymes is considered.

Clinical and pathogenetic significance of antioxidant defense impairments in children with pseudotuberculosis

Objective. To assess the impact of changes in the content of ceruloplasmin and the activity of myeloperoxidase, superoxide dismutase, glutathione peroxidase, catalase on an increase in the severity and development of a form of pseudotuberculosis progression in children, to determine prognostic criteria for the formation of a non-smooth progression of the disease. Patients and methods. 125 children with pseudotuberculosis of various severity and progression were examined. The control group consisted of 45 children with health group II. The content of ceruloplasmin, the total peroxidase activity of blood plasma, the activity of superoxide dismutase, glutathione peroxidase, catalase, and myeloperoxidase were determined. Results. An increase in the activity of superoxide dismutase, myeloperoxidase and catalase in the acute period of pseudotuberculosis in all groups of children was determined. During the period of early convalescence an increase in the activity of superoxide dismutase, myeloperoxidase, and catalase against the background of comparable values of ceruloplasmin and glutathione peroxidase activity was observed in children with severe pseudotuberculosis. Conclusion. The results of the study prove that the mechanisms of non-smooth progression formation and an increase in the severity of pseudotuberculosis in children are mediated by an imbalance in the functioning of antiperoxides. A decrease in the activity of glutathione peroxidase due to an increase in the functioning of catalase in erythrocytes, no increase in the content of ceruloplasmin in the blood plasma during the acute period and the period of early convalescence serve as a prognostic criterion for the formation of a more severe degree and non-smooth progression of pseudotuberculosis. Key words: children, pseudotuberculosis, oxidative stress, antioxidant system

Arylesterase activity of paraoxonase 1 and intensity of oxidative processes in the blood of dialysis patients

This study aimed to investigate the arylesterase activity of paraoxonase 1 (PON-1) in patients with end-stage renal disease (ESRD) and its relationship with oxidative stress markers. Methods. We conducted a one-time prospective observational study involving 58 ESRD patients. Among them, there were 20 hemodialyses (HD) patients and 38 patients treated with peritoneal dialysis (PD). The activity of PON-1 in serum was determined spectrophotometrically by the number of phenolic complexes formed using phenylacetate. Besides, spectrophotometrically the concentrations of malondialdehyde, serum concentrations of ceruloplasmin, thiol groups and total peroxidase activity (TPA) of erythrocyte were determined. The reference group consisted of 30 conditionally healthy individuals. Results. The arylesterase activity of the PON-1 in reference group was 6.57 kU/L versus 2.25 kU/L in HD patients and 4.26 kU/L in PD patients (p ˂ 0.0001). A direct correlation was found between arylesterase activity of PON-1 and ceruloplasmin concentration (p = 0.004), and TPA (p = 0.02) in HD patients. The activity of PON-1 in the serum of PD patients was associated with high-density lipoproteins (p ˂ 0.0001). Conclusions. We observed a decrease in the arylesterase activity of PON-1 in ESRD patients compared to the control group. The lowest activity of PON-1 is determined in HD patients. Moreover, the association of the PON-1 activity with a decrease in antioxidant blood markers was found. The enzyme activity in PD patients correlated with increased blood HDL. Further studies involving a larger dialysis cohort of patients are needed to determine the pathogenetic role of PON-1 activity in the development of cardiovascular events in ESRD patients.

ALPHA–LIPOIC ACID ANTIOXIDANT EFFICIENCY IN TREATMENT OF PERITONEAL DIALYSIS PATIENTS

The aim of the study was to evaluate the effectiveness of the antioxidant alpha–lipoic acid in peritoneal dialysis (PD) patients taking into account the state of lipid peroxidation (LPO) and antioxidant protection (AOP) before and after treatment. Patients and methods. The research revealed the intensity of oxidative processes in 20 patients treated with continuous ambulatory peritoneal dialysis (CAPD) on the basis of а–lipoic acid applied parenterally in a dose of 600 mg for 2–weeks followed by a transfer to the 6 weeks of oral reception. The intensity of oxidative processes was evaluated before and after treatment through determining the content of MDA in serum (MDAs) and erythrocytes (MDAe). AOP activity was evaluated by the content of the antioxidant enzyme ceruloplasmin (CP), transferrin (Tr), SH–groups and total peroxidase activity (TPA) of red blood cells. The control group consisted of30 individuals comparable on for age and sex. Results. The effects on the study of PD patients (positive decrease of MDAs, increase in CP higher than control group, a significant increase in the content of SH–groups (p=0,04), TPA (p=0,009), Tr (p=0,002) and catalase serum) demonstrated a considerable positive dynamics of LPO /AOP influenced by the use of а–lipoic acid. Conclusions. The research opens up the prospect for further study ofLPO /AOP blood in PD patients and proves the application expediency of alpha–lipoic acid for this group. Use of the latter lowers the activity of oxidative processes significantly and restores AOP indicators substantially, which in turn minimizes the negative influence of oxidative stress on a patient’s body.

ANTIOXIDANT EFFECTOF NUCLEINAT SODIUM IN PATIENTS WITH CHRONIC KIDNEYDISEASE І–II STAGES: UNCOMPLICATED PYELONEPHRITIS

Objective: to determine the antioxidant effects of Nucleinat sodium in patients with uncomplicated recurrent pyelonephritis. Material and methods. We have analyzed the indicators of oxidant/ antioxidant (O/ A) balance in the blood of 55 patients with uncomplicated recurrent pyelonephritis. Women were randomized into 2 groups: I (n=30) consisted of patients treated with Nucleinat sodium at a dose of 0.25 mg 4 times daily for 14 days to II (n=25) included patients who used only antibacterial therapy (according to the set sensitivity identified pathogens). The control group consisted of 20 conditional healthy donors, matched for sex and age. Results. In the blood ofpatients prior to treatment were observed reduction of total peroxidase activity of red blood cells (p<0.0001), ceruloplasmin (p=0,03), SH–groups (p=0.001) and increase in serum MDA, and oxidative stress index (p<0.0001) compared with the conditionally healthy donors. Comprehensive treatment with Nucleinat sodium statistically significantly led to normalization of these parameters and decrease of urine N–acetyl–p–D– glucosaminidase and p–galactosidase (p<0,001 and p=0.04, respectively). Conclusions. For the treatment of uncomplicated recurrent pyelonephritis appropriate to apply Nucleinat sodium at a dose of 0.25 mg 4 times / day, which helps to reduce the activity of oxidative processes and the negative impact of oxidative stress on the patient, and increases of antioxidant protection.

A Method for Prediction of Graft Incompatibility in Sweet Cherry

This study was carried out on 1-year old trees of ‘0900 Ziraat’ variety grafted onto ‘Kuş kirazi’, ‘Kara idris’, ‘Sari idris’, ‘MaxMa 14’, ‘MaxMa 60’ and ‘Gisela 5’ in order to determine their compatibility. For this purpose, total peroxidase activity was determined by spectrophotomery assay. Taking ground tissue samples were planned three times as before the grafting (beginning), and then 8 and 12 months after grafting. Total peroxidase activities of rootstocks before grafting varied between 10.80 ΔAg.min. (‘Kuş kirazi’) and 7.83 ΔAg.min. (‘Kara idris’) and were found to be statistically important. The peroxidase activity of ‘0900 Ziraat’ was 11.07ΔAg.min. and the closest value occurred in Prunus avium rootstock. The most different values occurred in rootstocks of ‘Kara idris’ and ‘Gisela 5’. The results showed that peroxidase activity increased in rootstock and graft scion. This increase had higher values in heterogenetic combinations especially in ‘0900 Ziraat’/‘Gisela 5’ and ‘0900 Ziraat’/‘Kara idris’ grafts. Peroxidase activity was decreased at the 12th month for all combinations. The highest value was obtained from ‘0900 Ziraat’/‘MaxMa 14’ combinaion with 29.17 ΔAg.min. while lowest one was ‘0900 Ziraat’/‘Kuş kirazi’ with 17.39. The findings showed that peroxidase activity could be used as a parameter in early determination of graft incompatibility.

Comparison of Protein Profile and Peroxidases in Bush and Vine-type Tropical Pumpkin

Comparisons of total peroxidase activity and peroxidase isozymes as well as protein profiles among segregating, near-isogenic bush and vine phenotypes of pumpkin (Cucurbita moschata Duchesne) were investigated. Peroxidase activities of internode and leaf tissues of the bush plants were higher than those of respective vine tissues. Roots of bush plants, however, had a lower peroxidase activity than vine plants. In both bush and vine plants, peroxidase activities were lower in leaf tissues than in root and internode tissues. Electrophoretic comparisons revealed qualitative differences in peroxidase patterns in internodes between bush and vine plants. Moreover, qualitative differences between internode and root profiles were found between bush and vine plants in C. moschata. In conclusion, the results of this report revealed that a single gene conferring the bush phenotype in C. moschata might affect the relative expression of peroxidase activity, peroxidase isozymes, and protein profiles in leaf, internode, and root tissues.

Ethylene-Insensitive Tobacco Shows Differentially Altered Susceptibility to Different Pathogens

Transgenic tobacco plants (Tetr) expressing the mutant etr1-1 gene from Arabidopsis thaliana are insensitive to ethylene and develop symptoms of wilting and stem rot when grown in nonautoclaved soil. Several isolates of Fusarium, Thielaviopsis, and Pythium were recovered from stems of diseased Tetr plants. Inoculation with each of these isolates of 6-week-old plants growing in autoclaved soil caused disease in Tetr plants but not in nontransformed plants. Also, when 2-week-old seedlings were used, nontransformed tobacco appeared nonsusceptible to the Fusarium isolates, whereas Tetr seedlings did develop disease. Tetr seedlings were not susceptible to several nonhost Fusarium isolates. In contrast to results with Fusarium isolates, inoculation of 2-week-old seedlings with a Thielaviopsis isolate resulted in equal symptom development of nontransformed and Tetr tobacco. In order to explore the potential range of pathogens to which Tetr tobacco plants display enhanced susceptibility, the pathogenicity of several root and leaf pathogens was tested. Tetr plants were more susceptible to the necrotrophic fungi Botrytis cinerea and Cercospora nicotianae and the bacterium Erwinia carotovora, but only marginally more to the bacterium Ralstonia solanacearum. In contrast, the biotrophic fungus Oidium neolycopersici, the oomycete Peronospora tabacina, and Tobacco mosaic virus caused similar or less severe symptoms on Tetr plants than on nontransformed plants. Total peroxidase activity of Tetr plants was lower than that of nontransformed plants, suggesting a role for peroxidases in resistance against necrotrophic microorganisms. A comparable range of pathogens was examined on Arabidopsis and its ethylene-insensitive mutants etr1-1 and ein2-1. With the exception of one Fusarium isolate, ethylene insensitivity increased susceptibility of Arabidopsis plants to a similar spectrum of necrotizing pathogens as in tobacco. Thus, both ethylene-insensitive tobacco and Arabidopsis plants appear to be impaired in their resistance to necrotrophic pathogens.