Calorie restriction (CR) has been shown to decrease reactive oxygen species (ROS) production an d retard aging in a variety of species. It has been proposed that alterations in membrane saturation are central to these ac tions of CR. As a step towards testing this theory, mice were assigned to 4 dietary groups (control and 3 CR groups) and fed AIN-93G diets at 95 % (control) or 60 % (CR) of ad libitum for 8 months. To manipulate membrane composition, the primary dietary fats for the CR groups were soybean oil (also used in the control diet), fish oil or lard. Skeletal muscle mitochondrial lipid composition, proton leak, and H 2 O 2 production were measured. Phospholipid fatty acid composition in CR mice was altered in a manner that reflected the n-3 and n-6 fatty acid profiles of their respective dietary lipid sources. Dietary lipid composition did not alter proton leak kinetics between the CR groups . However, the capacity of mitochondrial complex III to produce ROS was decreased in the CR lard compared to the other CR groups. The results of this study indicate that dietary lipid composition can influence ROS production in muscle mitochondria of CR mice. It remains to be determined if lard or other dietary oils can maximize the CR- induced decreases in ROS production., Y. Chen ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Influence of the pattern of effective rainfall on modeled hydrograph was investigated in the study. The modelling was performed with the U.S. Army Corps of Engineers hydrograph package HEC-HMS 3.2 and calibrated and validated on measured hydrographs of Glinscica watershed. Six different models of rainfall loss were applied and their effect on modeled hydrograph was evaluated. Peak discharge, time of peak discharge and runoff volume were compared. The best results with the lowest RMSE in the study was obtained with the SCS curve number loss method. Also synthetic hyetographs of different probability and duration were used. Three positions of the maximum rainfall intensity at 25, 50 and 75 % of the rainfall duration were applied. The results showed essential differences in simulated time to peak and also differences in peak discharge. The differences in time to peak increases considerably with the increasing of the rainfall duration. Finally, the results of constant intensity distribution of rainfall of different durations were compared with those obtained with typical rainfall distribution with the position of the maximum intensity at 50 %. Results showed considerable differences in peak discharge and time to peak by longer durations of the rainfall. and Práca obsahuje výsledky výskumu vplyvu efektívnych zrážok na modelovaný hydrograf. Odtok bol modelovaný pomocou nástroja U.S. Army Corps of Engineers hydrograph package HEC-HMS 3.2, potom kalibrovaný a verifikovaný na meraných hydrografoch povodia Glinscica. Vplyv zrážok na modelovaný hydrograf bol vypočítaný pre šesť rôznych modelov priebehu zrážok. Porovnali sme maximálne prietoky, časy ich trvania a odtečené množstvá. Najlepšie výsledky s najnižším RMSE sme získali s SCS modelom odtoku. Použili sme tiež syntetické hyetografy rozdielnej pravdepodobnosti a trvania. Použili sa tri polohy maximálnych intenzít zrážok; pre 25, 50 a 75 % ich trvania. Výsledky ukázali zásadný rozdiel v simulovaných časoch maximálneho prietoku a tiež rozdiely v maximálnych prietokoch. Rozdiely v časoch dosiahnutia maximálnych odtokov sa výrazne zvyšovali s časom trvania zrážky. Nakoniec sme porovnali výsledky výpočtov s konštantnými intenzitami rozdelenia s rôznym trvaním zrážky s tými, ktoré boli vypočítané s použitím typických rozdelení, s polohou maximálnej intenzity zrážok pri 50 % ich trvania. Výsledky ukazujú významné rozdiely v maximálnych prietokoch a v časoch ich dosiahnutia v závislosti od trvania zrážky.
Gamma irradiation with a dose of 5.7 Gy within 30 min before partial hepatectomy (PHE) caused latent damage in the intact rat liver. This was expressed in the course of proliferation induced in the liver remnant by inhibition of the regenerative process, which was indicated by a decreased mitotic index and cellularity, an increased ratio of metaphases/prophases and a high chromosomal aberration frequency. The preparation of essential phospholipids (ESSENTIALE) that was injected in a dose of 360 mg/kg (i.p.) either 24 h before irradiation or 30 min after irradiation or repeatedly before and after irradiation, markedly stimulated the process of liver regeneration after PHE in both nonirradiated and irradiated rats. It moderated all the alterations induced by irradiation, especially changes in cellularity. The most effective was the repeated administration of ESSENTIALE whereas its single administration before irradiation was more effective than that after irradiation. Our results suggest that ESSENTIALE has not only a stabilizing effect on cell membranes, but also mitigates damage of genetic material induced by irradiation.
The aim of this study was to observe the effect of folate and antioxidants alone on homocysteine levels and oxidative stress markers, and to evaluate whether their co-administration promotes their effects. One hundred patients with hyperhomocysteinemia were randomized into four equal groups, which were then treated with folate, antioxidants or
folate plus antioxidants for 2 months; group IV was a control group. Serum homocysteine, folate and oxidative stress markers were measured before the study, at the end of folate and/or antioxidants administration and 3 months later. Folate caused a significant decrease in homocysteine concentration. Antioxidants did not influence homocysteine concentration, but they improved the antioxidative defense (plasma antioxidant capacity and intraerythrocyte
glutathione were increased) and partially prevented lipid peroxidation (malondialdehyde level was slightly decreased). Supplementation with folate had a similar effect on intracellular glutathione and plasma malondialdehyde. Simultaneous administration of folate and antioxidants did not show any additive effect with the exception of a slower decrease of folate concentration after its supplementation had been discontinued. Folate may be considered as an effective antioxidant in patients with hyperhomocysteinemia; this can be a result of decreased production of free radicals due to a reduced level of homocysteine. Its antioxidative effect cannot be promoted by co-administration of antioxidants.
The haemolytic action of HgCl2 (0, 15 mmol.l'1) was studied in relation to the ionic strength and concentration of glucose and saccharose in incubating medium. Blood from 94 donors, aged 19-46 years were used in our experiments. In relation to the ionic strength the haemolytic action was characteristic with two maxima of haemolysis. The first at low ionic strength and second one at the high. Both maxima in solutions containing saccharose were significantly diminished in glucose. These facts show a negative influence of saccharose on the haemorheological properties of the erythrocyte membrane.
Adiponectin is an adipocyte-derived hormone involved in the regulation of carbohydrate and lipid metabolism. Its concentrations are decreased in patients with obesity, type 2 diabetes and atherosclerosis and are higher in females than in males. Gender differences of adiponectin levels raise the possibility that sex hormones directly regulate its serum concentrations, which may in turn influence insulin sensitivity in different phases of the menstrual cycle. To test this hypothesis we measured serum adiponectin, estradiol, progesterone, luteinizing hormone and follicle-stimulating hormone concentrations daily throughout the menstrual cycle in six healthy women. Mean adiponectin levels strongly positively correlated with serum cortisol concentrations [R=0.94286; p=0.0048 (Spearman correlation test)], but were not significantly related to other anthropometric, biochemical and hormonal characteristics of the subjects (BMI, blood
glucose, insulin, testosterone, prolactin, cholesterol, HDL cholesterol, LDL cholesterol, triglycerides concentrations, or atherogenic index). Furthermore, no significant changes of serum adiponectin levels were found throughout the menstrual cycle. We conclude that changes in sex hormones during the menstrual cycle do not affect total circulating
adiponectin levels in healthy women. Therefore, the differences in insulin sensitivity in various phases of the menstrual cycle are not due to changes of circulating adiponectin levels.
The influence of increased solar UV-B radiation on the photosynthetic characteristics in cowpea seedlings (Vigna unguiculata) grown at optimal (Mgs) and low (Mgd) Mg levels were studied. Both higher UV-B and Mgd treatments caused significant drops of photochemical activities and net CO2 uptake rates (PN). Yet the UV-B-induced decrease in the photosynthetic efficiency was lesser in Mgd seedlings. The leaf Chl a fluorescence measurements proved that after receiving an enhanced UV-B radiation these seedlings showed a significant enhancement in their variable parts. The PSM oscillation of slow fluorescence kinetics was remarkably altered by both treatments. The PN also followed a typical inhibitory pattern as seen in photochemical activities. Concentrations of several chloroplast proteins in trifoliate leaves were significantly reduced by Mgd treatment and unaffected by the other two treatments. Whereas the contents of 43-47 kDa polypeptides in primary leaves were markedly reduced with a maximal effect in Mgd seedlings, no major difference was noted for combined stress. and A. Premkumar, G. Kulandaivelu.
To further investigate the role of insulin during preimplantation embryo development, we compared the effects of insulin on the development of mouse and bovine preimplantation embryos and on cell proliferation during culture in vitro in simplex media. The influence of insulin on the development of mouse zygotes was determined during cultivation in mSOF medium, alone or supplemented with glucose. Similarly, the effects of insulin on the bovine preimplantation embryo development were studied in mSOF medium. The addition of insulin into mSOF medium enhanced significantly the number of cells per mouse blastocyst. Moreover, when mSOF medium was supplemented with insulin and 0.2 mmol.l-1 glucose, the percentage of hatched blastocysts and the mean cell number of mouse blastocysts were significantly higher. Insulin had no significant effect on the development of bovine embryos, produced by in vitro fertilization of in vitro matured oocytes. Neither the rates of developing embryos nor the mean number of cells in blastocysts were different in comparison with control embryos. Our results suggest that the in vitro development of mouse embryos could be enhanced by the addition of insulin to the culture medium and is further improved by the addition of glucose. In contrast to this our results indicate that insulin has no detectable beneficial effect on the preimplantation development of bovine embryos in mSOF medium., J. Mihalik, P. Rehák, J. Koppel., and Obsahuje bibliografii
Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1b), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1b have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1b on brain γ-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 μg IL-1β or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1β. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1b administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1b induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.
The abandonment of less productive agricultural land and the intensification of agricultural land use are the main features of the Common Agricultural Policy (CAP) that Croatia will enforce now as new member of the EU. Due to
demographic changes and the economic transition in Croatia resulting from
war in the 1990s, substantial tracts of agricultural land were abandoned. We investigated two habitat types in the protected floodplain landscape of Lonjsko polje in the continental part of the country: arable land and pastures.
Both habitats were maintained by agricultural management and suffered from partial abandonment. Land abandonment increased the susceptibility to encroachment by the invasive plant species Amorpha fruticosa. Data on bird communities were obtained during the breeding season in 2010 while there were high water levels in the floodplain. Data were collected from 63 points, and a total of 1447 individuals from 70 species were recorded during
the study. We found that the bird community structure was primarily related to the presence/abandonment of agricultural land use and the habitat type. Further, we detected that the bird community structure in the same habitat type differed by management intensity. Open habitat specialists were most influenced by land abandonment. However, the conservation value (according to the Species of European Conservation Concern value, SPEC) of grazed pastures and abandoned pastures did not differ significantly, in part because the overgrown pastures with high water levels were found to be suitable for Acrocephalus species. The shift in bird community structure between abandoned and managed arable lands were smaller than those
detected in the pastoral communities. Because land abandonment is a widespread phenomenon in Croatia, we emphasize the urgent need
for a nationwide monitoring program for farmland birds to register the resulting changes in farmland bird communities and to develop appropriate agri-environment measures to mitigate the process.