The relationship between antioxidant enzymes and lipid peroxidation in senescent rat erythrocytes.

The aim of this study was to gain more complete information about the relationships between some endogenous antioxidants and the malondialdehyde (MDA) as a marker of lipid peroxidation, during D-galactose induced senescence. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and the concentrations of uric acid (UA) in plasma and MDA in erythrocyte's hemolysate, were determined in 15 D-galactose (D-gal), treated rats and compared with 15 placebo. The activity of the erythrocyte's CAT was found significantly increased due to the senescence. The ratio of the activities of antioxidant enzymes R=SOD/(GPx+CAT) was significantly decreased due to the senescence and negatively correlated with the MDA (rho=-0.524, p=0.045). The antioxidant enzymes SOD and GPx negatively correlated with the MDA, while CAT displayed no correlation. Further, the UA positively correlated with the ratio of activities of the antioxidant enzymes R=SOD/(GPx+CAT), (rho=0.564, p=0.029 for senescent rats). Obtained results may contribute to better understanding of the process of D-gal induced senescence in the erythrocytes.

Somatotype and stress hormone levels in young soccer players.

AIM: The relationship between somatotype and cortisol and adrenocorticotropic (ACTH) hormone concentrations at rest or after exercise in adolescent soccer players at different time points throughout a soccer season is not understood. Therefore, the aim of this study was to examine the relationship between somatotype and cortisol and ACTH concentrations at rest and after exercise in adolescent soccer players at different time points during a soccer season. METHODS: During the first 4 months of the soccer season, 47 soccer players (between 15-17 years of age) were tested at three different time points including at baseline, after 6 weeks, and at the end of 4 months. Testing included anaerobic threshold (AnT, km/h) and maximal speed of running (Max, km/h) were measured with Conconi protocol on treadmill. Before and after a maximal exercise Test, plasma levels of cortisol (ug/dL) and ACTH (pg/ml) were assessed by chemiluminometry enzyme amplificated method. Heath-Carter anthropometric somatotype model was used to determine 13 elements of somatotype. Descriptive statistics and multiple regression were used for statistical analysis (P<0.05). RESULTS: Body composition and AnT were not significantly different between each time point of testing. The mesomorph-ectomorph (N.=21), balanced mesomorph (N.=8) and balanced ectomorph (N.=7) were the most frequent somatotypes. There were significant decrements of cortisol plasma levels (at rest 33.4%; after test 27.46%), with insignificant changes of ACTH plasma levels, after 6 weeks of preparation phase and after finishing of half season, at rest and after maximal treadmill test. There were significant correlation between ACTH levels at rest (R=0.44; P<0.01) and some somatotypes (mesomorph endomorph, central and balanced endomorph) and ACTH levels after maximal exercise test (R=0.36; P<0.05) and balanced ectomorph and endomorph mesomorph. There were significant correlation between cortisol levels after maximal exercise test at the beginning of training process (R=0.59; P<0.01) and some somatotypes (mesomorph ectomorph, mesomorph endomorph, balanced endomorph and endomorph mesomorph) and after the finishing of training process (R=0.62; P<0.01) and some somatotypes (central, balanced ectomorph and mesomorph ectomorph). CONCLUSION: The significant decreases of cortisol plasma levels during soccer training process could indicate a stagnation of training process, accordingly with insignificant changes of AnT. The significant correlations of some somatotypes with stress hormonal responses could only suggest that the somatotype characteristics of young soccer players could be of interest in process of selection and planning of soccer training process with an essential need for more studies.

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.

In vivo study of pulp reaction to glass ionomer cements and dentin adhesives.

The aim of this study was to evaluate histopathologically the pulp tissue response of the researched materials 7 and 30 days after their application. The reaction of pulp tissue has been examined on first upper molars in 24 Wistar rats, following the previously set parameters. For that purpose, 48 class V cavities were prepared with a high-speed handpiece using a diamond burr under copious water-cooling. The cavities were divided into four groups. In the cavities from the first group we applied Fuji Lining LC, and in the secound group cavities we applied Fuji IX as a base. In the third and fourth group cavities we applied Prime and Bond and G Bong as a base. All the cavities were restored with liquid light cured composite. Seven days after the application, 3 rats from each group were killed and the restored teeth were extracted and immersed in a fixative solution, Osteomol. After removing the Osteomol, the specimens were processed according to histological procedures. The histological evaluation was made using a light microscope connected to a video camera. Thirty days after the application of the dental materials we re-did the procedure with the other restored teeth. For Fuji Lining LC and Fuji IX most of the specimens exhibited no pulpal response or slight inflammatory reaction associated with slight tissue disorganization during a seven-day period. A slight to moderate inflammatory pulpal response occurred in the specimens restored with G Bond, while Prime and Bond exhibited the strongest toxic effect on the pulp tissue. After 30 days the pulp tissue in all groups recovered and displayed a normal appearance.

The effect of various dental filling materials on artificially demineralized dentin.

The aim of this study was to determinate the influence of fluoride, released by all of the restorative materials in the process of remineralization. To achieve this, we measured the concentration of the incorporated fluoride and calcium in dentin. The research was done on 80 extracted third molars, in which we prepared first-class cavities. After the process of decalcination, we split the teeth into four differ-rent groups (with 20 in each). The teeth from each group were separated vertically, in two halves. On the experimental half we applied the examined material (Fiji IX, Fuji Lining LC, G Bond and Prime and Bond) and we used the other half as a control. Later, the specimens were put into a glass bowl together with remineralization solution and were incubated at a temperature of 37 C. The incorporated fluoride and calcium concentration was determined by a significant increase of spectrometer. After applying the specimens in a remineralization solution, we perceived that the level of incorporated Ca2+ on the teeth restored with Fuji IX and Fuji Lining LC was significantly higher compared to the level of incorporated Ca2+ on the teeth, restored with dentin materials. Based on the results from this experiment, the conclusion shows that fluoride, released from the materials and incorporated into the dentin, speeds up the process of remineralization on hard dental tissues.

Bioefficacy of budesonide loaded crosslinked polyelectrolyte microparticles in rat model of induced colitis.

A targeted delivery system for inflammatory bowel diseases, chitosan-Ca-alginate microparticles efficiently loaded with budesonide (BDS), were designed using one-step spray-drying process. They were eudragit-coated and examined for in vivo efficacy. Experimental colitis was induced by rectal instillation of 2,4,6-trinitrobenzene sulphonic acid (TNBS) into male Wistar rats. Drugs were administered by oral gavage daily for 5 days. Colon/body weight ratio, gross morphological and histological evaluation, and clinical activity score were determined as inflammatory indices. Individual clinical and histological evaluation showed that colitis severity was suppressed the most greatly in order BDS < BDS/C-Ca-A < E-BDS/C-Ca-A. Clinical activity score decreased in the same order. Statistical analyses of total score points indicate that the incorporation of BDS in microparticles had significant differences in favor of efficacy of designed delivery system with mucoadhesive and controlled release properties (one-way ANOVA, P < 0.05). The results established the prediction by previous in vitro studies.

Ghrelin signalling in guinea-pig femoral artery smooth muscle cells.

AIM: Our aim was to study the new signalling pathway of ghrelin in the guinea-pig femoral artery using the outward I(K) as a sensor. METHODS: Whole-cell patch-clamp experiments were performed on single smooth muscle cells, freshly isolated from the guinea-pig femoral artery. The contractile force of isometric preparations of the same artery was measured using a wire-myograph. RESULTS: In a Ca2+- and nicardipine-containing external solution, 1 mmol L(-1) tetraethylammonium reduced the net I(K) by 49 +/- 7%. This effect was similar and not additive to the effect of the specific BK(Ca) channel inhibitor iberiotoxin. Ghrelin (10(-7) mol L(-1)) quickly and significantly reduced the amplitudes of tetraethylammonium- and iberiotoxin-sensitive currents through BK(Ca) channels. The application of 5 x 10(-6) mol L(-1) desacyl ghrelin did not affect the amplitude of the control I(K) but it successfully prevented the ghrelin-induced I(K) decrease. The effect of ghrelin on I(K) was insensitive to selective inhibitors of cAMP-dependent protein kinase, soluble guanylyl cyclase, cGMP-dependent protein kinase or a calmodulin antagonist, but was effectively antagonized by blockers of BK(Ca) channels, phosphatidylinositol-phospholipase C, phosphatidylcholine-phospholipase C, protein kinase C, SERCA, IP(3)-induced Ca2+ release and by pertussis toxin. The ghrelin-induced increase in the force of contractions was blocked when iberiotoxin (10(-7) mol L(-1)) was present in the bath solution. CONCLUSIONS: Ghrelin reduces I(K(Ca)) in femoral artery myocytes by a mechanism that requires activation of Galpha(i/o)-proteins, phosphatidylinositol phospholipase C, phosphatidylcholine phospholipase C, protein kinase C and IP(3)-induced Ca2+ release.