Prolonged storage of isolated photosystem 2 (PS2)-enriched subchloroplast particles in the frozen statě leads to a decrease of the PS2 activity and to an increase of the energy transfer between chlorophyll (Chl)-proteins of the light-harvesting chlorophyll a/b (LHC)-PS2 complex. The energy transfer was less influenced than the PS2-mediated electron transport at freeze-thaw treatment of PS2 particles. The change of these parameters was not affected by the rate of freezing. The addition of cryoprotectants such as glycerol, trehalose or saccharose in the suspension medium prior to freezing preserved fo a different extent the PS2-mediated electron transport and the energy transfer between the Chl molecules of the LHC-PS2 complex.
Treatment with pertussis toxin (PTX) which eliminates the activity of Gi proteins effectively reduces blood pressure (BP) and vascular resistance in spontaneously hypertensive rats (SHR). In this study we have compared the functional characteristics of isolated arteries from SHR with and without PTX-treatment (10 μg/kg i.v., 48 h before the experiment). Rings of thoracic aorta, superior mesenteric artery and main pulmonary artery were studied under isometric conditions to measure the reactivity of these vessels to receptor agonists and to transmural electrical stimuli. We have found that the treatment of SHR with PTX had no effect on endothelium-dependent relaxation of thoracic aorta induced by acetylcholine. In PTX-treated SHR, the maximum contraction of mesenteric artery to exogenous noradrenaline was reduced and the dose-response curve to cumulative concentration of noradrenaline was shifted to the right. Similarly, a reduction in the magnitude of neurogenic contractions elicited by electrical stimulation of perivascular nerves was observed in the mesenteric artery from PTX-treated SHR. PTX treatment of SHR also abolished the potentiating effect of angiotensin II on neurogenic contractions of the main pulmonary artery. These results indicate that PTX treatment markedly diminishes the effectiveness of adrenergic stimuli in vasculature of SHR. This could importantly affect BP regulation in genetic hypertension., A. Zemančíková, J. Török, J. Zicha, J. Kuneš., and Obsahuje bibliografii a bibliografické odkazy
Parasitic organisms inhabiting the alimentary canal should permanently resist the destructive action of host digestive enzymes. The intestinal parasites were shown to produce specific protease inhibitors protecting them from proteolysis. However, little is known about this adaptive mechanism in cestodes so far, especially for the tapeworms dwelling inside the fish intestines. Here, we explored the ability to inactivate proteolytic enzymes in the fish tapeworm Eubothrium rugosum (Batsch, 1786) (Bothriocephalidea) parasitising the intestine of wild burbot, Lota lota (Linnaeus). The assays were conducted with different concentrations of commercial trypsin and homogenate of intestinal mucosa both being the sources of proteinases. The incubation of live E. rugosum in trypsin solutions of two different concentrations caused a significant decrease in the enzyme activity. The extent of activity reduction was dependent on trypsin concentration. At the same time, the inhibitory effect of the worm incubation medium turned out to be statistically insignificant. These findings suggest partial adsorption of the enzyme to the tegument surface, with its further inactivation. In contrast to the incubation medium, the worm extract suppressed over 80% of trypsin activity and nearly half of the proteolytic activity in the mucosa homogenate. Notably, the inhibitory activity of the tapeworms hardly depended on their size characteristics. Finally, the research has demonstrated secretion of proteinase inhibitor in E. rugosum, which appears to be essential for its survival in enzymatically hostile environment., Galina I. Izvekova, Tatyana V. Frolova, Evgeny I. Izvekov., and Obsahuje bibliografii
CEFRES Platform and its new premises within the Czech Academy of Sciences were inaugurated on October 7-8, 2015. In 2015, theCAS built a brand newlibrary in order to hostCEFRES’smore than 6,000 volumes alongwith its teamand Prague’s Francophone readers. The new library was inaugurated during a ceremony in the presence of French Ambassador Jean-Pierre Asvazadourian, President of CAS Jiří Drahoš and Rector of Charles University Tomáš Zima. CEFRES (French Research Center in Humanities and Social Sciences) was founded in Prague in 1991 with the aim to restart scientific exchanges between France and Central Europe as the latter underwent major changes after the fall of communism. One of CEFRES’s tasks since then has been to build up a network of research teams between France, the Czech Republic, Hungary, Poland and Slovakia. and Luděk Svoboda.
In hemodialyzed patients hormonal disturbances are known to occur. However, melatonin levels have not been completely studied. The aim of the study was to find whether changes in calcaemia affect melatonin secretion. For this reason we followed the nocturnal serum concentrations of melatonin and parathyroid hormone (PTH) in 9 hemodialyzed patients (6 women and 3 men, aged 37-65 years) both before and 1-3 months after parathyroidectomy at 6 p.m., 9 p.m., 11 p.m., 2 a.m., 5 a.m. and 7 a.m. At 6 p.m. blood samples to evaluate the levels of calcium and phosphate were also collected. Parathyroidectomy resulted in an increase in nocturnal melatonin levels. As expected, the parathyroidectomy was followed by considerable PTH decrease. PTH showed no nocturnal variation before or after parathyroidectomy. Calcium levels significantly decreased after the operation while phosphate levels increased. In summary, in hemodialyzed patients with hyperparathyroidism, parathyroidectomy significantly increases the nocturnal secretion of melatonin. Relationships between the pineal gland and parathyroid glands have yet to be elucidated., R. Kancheva, S. Sulková, F. Švára, M. Hill, L. Kanchev, I. Žofková., and Obsahuje bibliografii a bibliografické odkazy
Critical illness induces among other events production of proinflammatory cytokines that in turn interfere with insulin signaling cascade and induce insulin resistance on a postreceptor level. Recently, local renin-angiotensin system of adipose tissue has been suggested as a possible contributor to the development of insulin resistance in patients with obesity. The aim of our study was to determine local changes of the renin-angiotensin system of subcutaneous and epicardial adipose tissue during a major cardiac surgery, which may serve as a model of an acute stress potentially affecting endocrine function of adipose tissue. Ten patients undergoing elective cardiac surgery were included into the study. Blood samples and samples of subcutaneous and epicardial adipose tissue were collected at the beginning and at the end of the surgery. Blood glucose, serum insulin and adiponectin levels were measured and mRNA for angiotensinogen, angiotensin-converting enzyme and angiotensin II type 1 receptor were determined in adipose tissue samples using RT PCR. Cardiac surgery significantly increased both insulin and blood glucose levels suggesting the development of insulin resistance, while serum adiponectin levels did not change. Expression of angiotensinogen mRNA significantly increased in epicardial adipose tissue at the end of surgery relative to baseline but remained unchanged in subcutaneous adipose tissue. Fat expression of angiotensin-converting enzyme and type 1 receptor for angiotensin II were not affected by surgery. Our study suggests that increased angiotensinogen production in epicardial adipose tissue may contribute to the development of postoperative insulin resistance., T. Roubíček, M. Dolinková, J. Bláha, D. Haluzíková, L. Bošanská, M. Mráz, J. Křemen, M. Haluzík., and Obsahuje bibliografii a bibliografické odkazy
We studied the changes in seru m fibroblast growth factor-21 (FGF-21) concentrations, its mR NA, and protein expression in skeletal muscle and adipose tissue of 15 patients undergoing cardiac surgery. Blood samples were obtained: prior to initiation of anesthesia, prior to the start of extracorporeal circulation, upon completion of the surger y, and 6, 24, 48, and 96 hours after the end of the surgery. Tissue sampling was performed at the start and end of surgery. The mean baseline serum FGF-21 concentration was 63.1 (43.03-113. 95) pg/ml and it increased during surgery with peak 6 ho urs after its end [385.5 (274.55-761.65) pg/ml, p<0.001], and return ed to baseline value [41.4 (29.15-142.83) pg/ml] 96 hours afte r the end of the surgery. Serum glucose, insulin, CRP, IL-6, IL-8, MCP-1, and TNF-alpha concentrations significantly increased during the surgery. Baseline FGF-21 mRNA expression in skeletal muscle was higher than in both adipose tissue depots and it was not affected by the surgery. Epicardial fat FGF-21 mRNA increased after surgery. Muscle FGF-21 mRNA positively correlated with blood glucose levels at the end of the surgery. Our data suggest a possible role of FGF-21 in the regulation of glucose metabolism and insulin sensitivity in surgery-related stress., T. Kotulák ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Previously, increased diameter and enhanced myogenic tone were seen after 2-week 45º head-up (HUT2) in the rat. We studied the reversibility and the effect of extended tilt on this phenomenon using two experimental groups: HUT2 plus 2-week horizontal (HUT2HOR2), and 4-week tilting (HUT4). 4-weeks in normal cages (NC4) served as control. Diameter of saphenous vein (SV) in 2-20 mm Hg pressure range, wall and media thickness, endothelial and smooth muscle cell densities, and cell proliferation were measured. The diameter of SV from HUT4 was significantly larger compared with HUT2HOR2 or NC4 within the whole pressure range both in Krebs-Ringer (870.4±21.3 vs. 778.2±24.9 and 771.6±28.1 μm at 10 mm Hg, respectively) and in Ca2+-free solution. Myogenic and norepinephrine-induced vascular tone, wall and media thickness did not differ among the three groups. Endothelial cell density decreased in HUT4 (10.7±1.2) vs. HUT2HOR2 (15.1±1.0) and NC4 (15.3±0.6), while that of smooth muscle was unchanged. No cell proliferation marker was seen. In conclusion, both increased diameter and enhanced myogenic tone of SV seen in HUT2 proved to be reversible. HUT4 resulted in increased SV diameter, similarly to HUT2, however, vascular tone was not amplified. This suggests that a prolonged orthostatic load may readjust the function of smooth muscle., G. Raffai, C. Lódi, G. Illyés, G. Nádasy, E. Monos., and Obsahuje bibliografii a bibliografické odkazy
The heavy impact of obesity on the development and progression of cardiovascular disease has sparked sustained efforts to uncover the mechanisms linking excess adiposity to vascular dysfunction. Impaired vasodilator reactivity has been recognized as an early hemodynamic abnormality in obese patients, but also increased vasoconstrictor tone importantly contributes to their vascular damage. In particular, upregulation of the endothelin (ET)-1 system, consistently reported in these patients, might accelerate atherosclerosis and its complication, given the pro-inflammatory and mitogenic properties of ET-1. In recent years, a number of gut hormones, in addition to their role as modulators of food intake, energy balance, glucose and lipid metabolism, and insulin secretion and action, have demonstrated favorable vascular actions. They increase the bioavailability of vasodilator mediators like nitric oxide, but they have also been shown to inhibit the ET-1 system. These features make gut hormones promising tools for targeting both the metabolic and cardiovascular complications of obesity, a view supported by recent large-scale clinical trials indicating that novel drugs for type 2 diabetes with cardiovascular potential may translate into clinically significant advantages. Therefore, there is real hope that better understanding of the properties of gut-derived substances might provide more effective therapies for the obesity-related cardiometabolic syndrome., F. Schinzari, M. Tesauro, C. Cardillo., and Seznam literatury