Perinatal hypoxic-ischemic insult (HII) is one of the main devastating causes of morbidity and mortality in newborns. HII induces brain injury which evolves to neurological sequelae later in life. Hypothermia is the only therapeutic approach available capable of diminishing brain impairment after HII. Finding a novel therapeutic method to reduce the severity of brain injury and its consequences is critical in neonatology. The present paper aimed to evaluate the effect of sulforaphane (SFN) pre-treatment on glucose metabolism, neurodegeneration, and functional outcome at the acute, sub-acute, and sub-chronic time intervals in the experimental model of perinatal hypoxic-ischemic insult in rats. To estimate the effect of SFN on brain glucose uptake we have performed 18F-deoxyglucose (FDG) μCT/PET. The activity of FDG was determined in the hippocampus and sensorimotor cortex. Neurodegeneration was assessed by histological analysis of Nissl-stained brain sections. To investigate functional outcomes a battery of behavioral tests was employed. We have shown that although SFN possesses a protective effect on glucose uptake in the ischemic hippocampus 24 h and 1 week after HII, no effect has been observed in the motor cortex. We have further shown that the ischemic hippocampal formation tends to be thinner in HIE and SFN treatment tends to reverse this pattern. We have observed subtle chronic movement deficit after HII detected by ladder rung walking test with no protective effect of SFN. SFN should be thus considered as a potent neuroprotective drug with the capability to interfere with pathophysiological processes triggered by perinatal hypoxicischemic insult.
The recovery of total DNA content and recovery of total cytochrome c oxidase activity in the rat liver after partial hepatectomy is accelerated by triiodothyronine applied in three doses, two before and one immediately after liver resection. Triiodothyronine-treated animals already have higher cytochrome c oxidase activity before resection. The recovery of the tissue oxidative capacity after partial hepatectomy is more rapid in triiodothyronine-treated animals. These data indicate that hormonal activation of the liver regeneration process is involved.
We investigated the role of serotonin in cognitive activation of the frontal cortex. The serotonergic system was affected by the administration of an amino acids mixture without tryptophan (tryptophan depletion). In a placebo-controlled double-blind cross-over study with 20 healthy volunteers, we tested the hypothesis that a tryptophan (serotonin)
decrease affects the activation of prefrontal cortex by the Stroop test. Cognitive brain activation was evaluated by functional magnetic resonance imaging (fMRI). Tryptophan depletion decreased the plasma tryptophan level up to 90 % for five hours after the tryptophan-free drink had been consumed when compared with the same mixture with tryptophan (p ≤
0.0001). Tryptophan depletion did not affect the Stroop test performance. We compared fMRI activation in both conditions (tryptophan depletion and placebo) with plasma tryptophan levels as the covariates. The tryptophan
depletion increased the activation (fMRI signal) in the bilateral mediofrontal cortex, anterior cingulate and left dorsolateral prefrontal cortex. The present findings allow the postulate that serotonergic medial forebrain and cingulum bundle pathways play a role in the activity of cortical structures involved in Stroop test processing.
The effect of various photoperiods on circadian rhythms of chosen parameters was investigated in laboratory rats. SPF male Wistar rats were adapted for six weeks to artificial light-dark cycles (LD 8 : 16, 12 : 12, 16 : 8). The light was switched on at 07.00 h in all regimens. The rats were killed at 3-hour intervals within 24 h, the serum concentration of corticosterone, insulin,glucose, food and water intake was determined. The external and computative acrophases of corticosterone varied in every photoperiod being dependent on the duration of light, the mesor values decreased in LD 16 : 8 in comparison with other photoperiods. The external acrophase of insulin was located 4 h after light onset in LD 8 : 16 and 12 : 12, in LD 16 : 8 one hour before light onset. The mesor values were approximately equal in all photoperiods. The circadian rhythms of glucose were similar in all regimens. Circadian variation of food and water consumption culminated at the same time in all regimens, the amount of food consumed in light increased with the light duration. Various photoperiods remarkably influenced circadian oscillations of corticosterone and in part food and water intake which could be considered as photoperiodic traits.
Chronic kidney disease (CKD) is associated with increased concentration of intracellular calcium, which is pathological and may lead to irreversible damage of cell functions and structures. The aim of our study was to investigate the impact of 6 months vitamin D3 supplementation (14 000 IU/week) on free cytosolic calcium concentration ([Ca2+]i) and on the plasma membrane calcium ATPase (PMCA) activity of patients with CKD stage 2-3. PMCA activity of patients was also compared to that of healthy volunteers. Vitamin D3 supplementation of CKD patients resulted in the decrease of [Ca2+]i (119.79±5.87 nmol/l vs. 105.36± 3.59 nmol/l, n=14, P<0.001), whereas PMCA activity of CKD patients (38.75±22.89 nmol Pi/mg/h) remained unchanged after vitamin D3 supplementation (40.96±17.74 nmol Pi/mg/h, n=14). PMCA activity of early stage CKD patients before supplementation of vitamin D3, was reduced by 34 % (42.01±20.64 nmol Pi/mg/h) in comparison to healthy volunteers (63.68±20.32 nmol Pi/mg/h, n=28, P<0.001). These results indicate that vitamin D3 supplementation had a lowering effect on [Ca2+]i and negligible effect on PMCA activity in CKD patients., M. Morvová Jr., I. Lajdová, V. Spustová, M. Zvarík, L. Šikurová., and Obsahuje bibliografii
Neuroprotective effects of estrogens and progesterone have been widely studied in various experimental models. The present study was designed to compare possible neuroprotective effects of 17alpha-estradiol, 17beta-estradiol, and progesterone on oxidative stress in rats subjecte d to global cerebral ischemia. Global cerebral ischemia was induced in ovariectomized female rats by four vessel occlusion for 10 min. Following 72 h of reperfusion, levels of malondialdehyde (MDA, oxidative stress marker), and reduced glutathione (GSH, major endogenous antioxidant) were assessed in hippocampus, striatum and cortex of rats treated with either 17alpha-estradiol, 17beta-estradiol, progesterone or estradiol + progesterone beforehand. Steroid administration ameliorated ischemia-induced decrease in GSH and increase in MDA levels. Our data offers additional evidence that estrogens and progesterone or combination of two exert a remarkable neuroprotective effect reducing oxidative stress., V. H. Ozacmak, H. Sayan., and Obsahuje seznam literatury
The effects of /¿-adrenergic agonists isoprenaline, fenoterol and clenbuterol on the activity of adenylyl cyclase from ciliary processes and on intraocular pressure were examined in pigmented rabbits. Isoprenaline, fenoterol and clenbuterol stimulated adenylyl cyclase activity in vitro, but clenbuterol behaved as a partial agonist. Preincubation of ciliary processes with any of these three drugs led to the heterologous desensitization of adenylyl cyclase to the stimulatory effects of beta-adrenergic agonists or vasoactive intestinal peptide (VIP). This desensitization was dose-dependent and was expressed mainly as a decrease of the highest effects of stimulatory drugs. The exact mechanism of this phenomenon is not yet known. After topical administration, all three tested /¿-adrenergic agonists decreased intraocular pressure with approximately the same intensity. The relationship between ocular hypotensive effects of /¿-adrenergic agonists and their effects on adenylyl cyclase of ciliary processes is discussed. It is concluded that ocular hypotensive effects of adrenergic agonists and other drugs stimulating adenylyl cyclase cannot be explained simply by stimulation or desensitization of adenylyl cyclase of ciliary processes.
In cardiac surgical patients we investigated the effects of cardiopulmonary bypass (CPB) with a hollow fiber membrane oxygenator on blood clotting measured by thromboelastography (TEG). We found only a minimal change in the strength of blood clot described either by the TEG parameter MA (maximum amplitude) or by the shear modulus G calculated from MA. After CPB there was also a significant tendency towards hypercoagulation as defined by shortened parameters R, K and increased ?-angle. After comparison with published data obtained in cardiac surgical patients using a bubble oxygenator we conclude that currently used extracorporeal technology exerts a less negative influence on blood clotting than had been conceived previously., M. Horáček, K. Cvachovec., and Obsahuje bibliografii
The effects of condensed tannins (CTs) extracted from five species of plants on egg hatching and larval development of Teladorsagia circumcincta (Stadelmann, 1894) (syn. Ostertagia circumcincta) were evaluated using in vitro bioassays. The extracts of CTs were obtained from Lotus pedunculatus (LP), Lotus corniculatus (LC), Dorycnium pentaphyllum (DP), Dorycnium rectum (DR) and Rumex obtusifolius (RO). The results of egg hatching assay showed that about 53%, 68%, 51%, 60% and 46% of the eggs hatched when in vitro incubations contained 900 mg/ml of CTs from LP, LC, DP, DR and RO, respectively (P< 0.001 relative to control incubation), while in control incubations (no CT added) 87% of the eggs hatched. In the larval development assay, development was allowed to proceed for 7 days, by which time 89% of the hatched larvae in control wells (no CTs) had reached the infective third stage (L3). In incubations containing 200 mg CT from LP, LC, DP, DR and RO/ml, about 8%, 15%, 14%, 8% and 4% of the eggs attained full development to L3 larvae, respectively (P< 0.001 relative to control incubation). Only 1% of the eggs were able to develop to L3 larvae in incubations containing 400 mg CT extracted from LC/ml, whilst in the incubations containing the same concentration of other CTs the eggs were not able to develop to L3 larvae. It seems that CTs are not only slowing down the larval development but also kill the undeveloped larvae. At 400 mg/ml, for example, CT from LP, LC, DP, DR and RO killed 67%, 48%, 68%, 93% and 91% of first-stage (L1) and second-stage (L2) larvae, respectively. This study shows that CTs are able to disrupt the life cycle of nematodes.