Lecithin:retinol acyltransferase (LRAT) is the major enzyme responsible for retinol esterification in the mammalian body. LRAT exhibits specific activity in the cells with active retinol metabolism where it converts retinols into retinyl esters, which represents the major storage form of retinol. Besides hepatic stellate cells in the liver, LRAT appears to have a key physiologic role in several other tissues. In this study, we generated a transgenic reporter mouse expressing green fluorescence protein (EGFP) under the control of region containing -1166 bps from promoter upstream from the putative transcriptional start site and 262 bps downstream of this start. Transgenic reporter mice exhibited specific expression in eyes and testes. In eyes, expression of EGFP-reporter is found in lens and lens epithelium and fibers from embryo to adulthood. In testes, LRAT-EGFP reporter is expressed both in Sertoli and in spermatocytes marking initiation of spermatogenesis in prepubertal mice. Our data show that the examined LRAT regulatory region is sufficient to achieve strong and selective expression in the eye and testes but not in liver and other organs., D. Prukova, Z. Ileninova, B. Antosova, P. Kasparek, M. Gregor, R. Sedlacek., and Obsahuje bibliografii
The novel environment of a metabolic cage can be stressful for rodents, but few studies have attempted to quantify this stress-response. Therefore, we determined the effects on mean arterial pressure (MAP) and heart rate (HR), of placing mice of both sexes in metabolism cages for 2 days. After surgical implantation of a carotid artery catheter mice recovered individually in standard cages for 5 days. Mice then spent 2 days in metabolism cages. MAP and HR were monitored in the standard cage on Day 5 and in metabolism cages on Days 6-7. MAP increased by 18±3 and 22±4 %, while HR increased by 27±4 and 27±6 %, in males and females, respectively, during the first hours after cage switch. MAP decreased to baseline in the fourth and eighth h following metabolism cage switch in males and females, respectively. However, HR remained significantly elevated in both sexes during the entire two-day period in metabolism cages. Females had lower MAP than males both pre- and post- metabolism cage switch, but there were no sex differences in HR. These results demonstrate sustained changes in cardiovascular function when mice are housed in metabolism cages, which could potentially affect renal function., C. C. Hoppe ... [et al.]., and Obsahuje seznam literatury
Tumor necrosis factor a (TNFa) was found to be significantly increased in skeletal muscles and retroperitoneal fat of obese insulin-resistant Koletsky rats as compared to control Wistar rats. This increase was accompanied by a depression of insulin receptor protein tyrosine kinase (PTK) activity. Neither the insulin-binding capacity nor insulin receptor affinity were related to this TNFa increase in these tissues. In the liver, no significant changes of TNFa content and only a lowering of insulin-binding capacity were found. It is concluded that an increased TNFa content in muscles and fat (but not in the liver) contributes to insulin resistance by lowering insulin receptor protein tyrosine kinase activity, while other insulin receptor characteristics (insulin-binding capacity and affinity of insulin receptors to the hormone) do not seem to be influenced by this factor., A. Hřebíček, M. Rypka, Z. Chmela, J. Veselý, M. Kantorová, V. Golda., and Obsahuje bibliografii
Endogenous regulators, such as angiotensin-II (AngII), endothelin-1 (ET-1) and urotensin-II (U-II) are released from various cell types and their plasma levels are elevated in several cardiovascular diseases. The present study evaluated a potential crosstalk between these systems by investigating if the myocardial effects of U-II are modulated by AngII or ET-1. Effects of U-II (10-8 , 10 -7 , 10 -6 M) were tested in rabbit papillary muscles in the absence and in the presence of losartan (selective AT1 receptor antagonist), PD-145065 ( nonselective ET-1 receptors antagonist), losartan plus PD-145065, AngII or ET-1. U-II promoted concentration-dependent negative inotropic and lusitropic effects that were abolished in all experimental conditions. Also, U-II increased resting muscle length up to 1.008±0.002 L/Lmax. Correcting it to its initial value resulted in a 19.5±3.5 % decrease of resting tension, indicating increased muscle distensibility. This effect on muscle length was completely abolished in the presence of losartan and significantly attenuated by PD-145065 or losartan plus PD-145065. This effect was increased in the presence of AngII, resulting in a 27.5±3.9 % decrease of resting tension, but was unaffected by the presence of ET-1. This study demonstrated an interaction of the U-II system with the AngII and ET-1 systems in terms of regulation of systolic and diastolic function., A. P. Fontes-Sousa ... [et al.]., and Obsahuje seznam literatury
This study appears from an experiment previously carried out in New Zealand white rabbits. Allogenic mesenchymal stem cells (MSCs) were transplanted into an iatrogenically-created defect in the lateral section of the distal physis of the left femur in 10 miniature pigs. The right femur with the same defect served as a control. To transfer MSCs, a freshly prepared porous scaffold was used, based on collagen and chitosan, constituting a compact tube into which MSCs were implanted. The pigs were euthanized four months after the transplantation. On average, the left femur with transplanted MSCs grew more in length (0.56±0.14 cm) compared with right femurs with physeal defect without transplanted MSCs (0.14 ± 0.3 cm). The average angular (valgus) deformity of the left femur had an angle point of 0.78°, following measurement and X-ray examination, whereas in the right femur without transplantation it was 3.7°. The initial results indicate that preventive transplantation of MSCs into a physeal defect may prevent valgus deformity formation and probably also reduce disorders of the longitudinal bone growth. This part of our experiment is significant in the effort to advance MSCs application in human medicine by using pig as a model, which is the next step after experimenting on rabbits., L. Plánka ... [et al.]., and Obsahuje seznam literatury
Electrogastrography (EGG) is a non-invasive method for the assessment of gastric myoelectrical activity. Porcine EGG is comparable with human one. The purpose of this study was to evaluate the effect of atropine and neostigmine on the EGG in experimental pigs. Adult female pigs were administrated atropine (1.5 mg i.m., n=6) and neostigmine (0.5 mg i.m., n=6) after the baseline EGG, followed by a 90-min trial recording (MMS, Enschede, the Netherlands). Running spectral analysis was used for the evaluation. The results were expressed as dominant frequency of slow waves and EGG power (areas of amplitudes). Neostigmine increased continuously the dominant frequency and decreased significantly the EGG power. Atropine did not change the dominant frequency significantly. However, atropine increased significantly the EGG power (areas of amplitudes) from basal values to the maximum at the 10-20-min interval. After that period, the areas of amplitudes decreased significantly to the lowest values at the 60-90-min interval. In conclusion, cholinergic and anticholinergic agents affect differently EGG in experimental pigs., J. Květina, I. Tachecí, M. Pavlík, M. Kopáčová, S. Rejchrt, T. Douda, M. Kuneš, J. Bureš., and Obsahuje bibliografii
The purpose of this study was to determine the production of metalloproteinases (MMP) 2 and 9 following UV-B irradiation in human corneal epithelial cells and fibroblasts. Epithelial cells and fibroblasts were separated from human donor corneas and exposed to UV-B lamp irradiation for 20, 40, 80 and 120 s. Media samples were collected at 8, 24, 48 and 72 h and gelatinase A and B production was assayed by the ELISA test. Statistical significance of production was assessed by the paired t-test. Increased production of MMP-2 was found in human corneal fibroblasts in response to UV-B irradiation. A statistically significant production of MMP-2 was not observed in human corneal epithelial cells following UV-B exposure. We did not detect any increase in MMP-9 after irradiation in either epithelial cells or fibroblasts. MMP-2 is produced by the corneal fibroblasts in the acute phase after UV-B irradiation. MMP-9 is not released in vitro following UV-B irradiation damage and therefore does not directly participate in the pathophysiology of acute photokeratitis., I. Kozák, D. Klisenbauer, T. Juhás., and Obsahuje bibliografii
This study investigated the value of oxygen (O2) pulse curves obtained during cardiopulmonary exercise testing (CPET) for the diagnosis of coronary artery disease (CAD). Forty patients with known coronary anatomy (35.0 % normal, 27.0 % single-vessel and 38.0 % multivessel CAD) underwent CPET with radiotracer injection at peak exercise, followed by myocardial scintigraphy. O2 pulse curves were classified as: A-normal, B-probably normal (normal slope with low peak value); C-probably abnormal (flat, with low peak value); or D- definitely abnormal (descending slope). Sensitivity, specificity, positive and negative predictive values of the O2 pulse curve pattern (A or B vs. C or D) for the diagnosis of CAD were, respectively, 38.5 %, 81.3 %, 76.9 %, and 44.8 %. The concordance rate between the abnormal O2 pulse curve pattern and ischemia in myocardial scintigraphy was 38.1 %. Age and the extent of scintigraphic perfusion defect, but not the abnormal O2 pulse curve patterns (B or C or both combined) were independently associated with CAD. In conclusion, the O2 pulse curve pattern has low diagnostic performance for the diagnosis of obstructive CAD, and the abnormal curve pattern was not associated with myocardial ischemia defined by scintigraphy., A. De Lorenzo, C. L. Da Silva, F. C. Castro Souza, R. De Souza Leão Lima., and Obsahuje bibliografii
The purpose of this study was to determine the role of lipotoxicity in vascular smooth muscle (VSM). C1-BODIPY 500/510 C12 used to assess the ability of VSM A7r5 cells to transport long-chain fatty acids showed that lipid transport did not appear to limit metabolism. Thin layer chromatography revealed that storage of transported fatty acid occurred primarily as mono- and diglycerides and fatty acids but not as triglycerides. We used lipid-induced apoptosis as a measure of lipotoxicity and found that 1.5 mM palmitate (6.8:1) bound to albumin resulted in a 15-fold increase in the number of apoptotic cells compared to the control at 24 hours. This apoptosis did not seem to be due to an increase in reactive oxygen species (ROS) since VSM cells incubated in palmitate showed less ROS production than cells incubated in albumin only. Similar exposure to oleate did not significantly increase the number of apoptotic cells compared to the control. Oleate actually significantly attenuated the apoptosis induced by palmitate, suggesting that unsaturated fatty acids have a protective effect on cells undergoing palmitate-induced apoptosis. These results suggest that vascular smooth muscle is vulnerable to lipotoxicity and that this lipotoxicity may play a role in the development of atherosclerosis., H. M. Mattern, C. D. Hardin., and Obsahuje bibliografii a bibliografické odkazy