The study was designed to prove the hypothesis that lipopolysaccharide (LPS)-induced fever elicits the changes in surfactant specific proteins, potentially related to thermal tachypnea. In adult rats fever was induced by intraperitoneal administration of LPS at a dose 100 μg/kg of body weight; control group received saline. Respiratory parameters, arterial blood gases and pH and colonic body temperature (BT) were recorded. Five hours later, surfactant proteins (SP) A, B, C and D were evaluated in bronchoalveolar lavage fluid (BALF) and lung tissue (LT). LPS evoked monophasic thermic response (at 300 min 38.7±0.2 vs. 36.4±0.3 °C, P<0.05) and an increase in minute ventilation due to changes in breathing rate and tidal volume. LPS-instilled animals had higher levels of SP-A and SP-D in LT (P<0.05 and 0.01), and higher SP-D in BALF (P<0.01) than controls. SP-B increased in LT and SP-C in BALF of animals with LPS (both P0.05 vs. controls). The changes in all surfactant specific proteins are present in LPS-induced fever. Alterations of proteins related to local immune mechanisms (SP-A, SP-D) are probably a part of general inflammatory response to pyrogen. Changes in proteins related to surface activity (SP-B and SP-C) might reflect the effort of the body to stabilize the lungs in thermal challenge., M. Kolomaznik, I. Zila, J. Kopincova, D. Mokra, A. Calkovska., and Obsahuje bibliografii
The role of cortico-tectal pathways in auditory signal processing was studied in anesthetized rats by comparing the extracellular single unit activity in the inferior colliculus (IC) before and after functional ablation of the auditory cortex (AC) by tetrodotoxin (TTX). The responses of several IC neurons to sound stimuli were simultaneously recorded with a 16-channel electrode probe introduced into the IC. Click-evoked middle latency responses (MLR) recorded from the AC were suppressed for several hours after TTX injection. During AC inactivation the firing rate of IC neurons increased (40 % of neurons), decreased (44 %) or did not change (16 %) in comparison with control conditions. In several IC neurons, TTX injection resulted in alterations in the shape of the rate-level functions. Response thresholds, tuning properties and the type of discharge pattern of IC neurons were not altered during AC inactivation. However, in one-third of the neurons, the initial part of the response was less altered than the later, sustained part. In two-thirds of neuronal pairs, functional decortication resulted in a change in the cross-correlation coefficient. The results reveal the complex changes that appear in IC neuronal activity after functional ablation of the ipsilateral auditory cortex., J. Popelář, F. C. Nwabueze-Ogbo, J. Syka., and Obsahuje bibliografii
Oxidative stress may be caused by an increased rate of ATP resynthesis during physical exercise. The aim of this study was to compare changes in the prooxidant-antioxidant state of blood plasma between men and women after maximal-intensity exercise, and to assess the relationship between these changes and the value of the maximal oxygen uptake (VO2max) as well as between these changes and the value of post-exercise disruptions in acid-base balance. Study participants comprised 10 women (20.7±0.5 years) and 10 men (22.3±0.5 years) who were physically active but did no t engage in competitive sports training. VO2max was determined via treadmill incremental test (VO2max relative to body mass: 44.48±1.21 ml/kg/min and 59.16±1.55 ml/kg/min for women and men, respectively). The level of acid-base balance indicators (ABB), lactate concentration (La-), the level of total oxidative status (TOS), the level of total antioxidative capacity (TAC), an d uric acid (UA) concentration were measured before and after the test. An oxidative stress indicator (OSI) was also calculated. Men showed a significant post-exercise increase in the level of TOS and OSI, while women showed a significant post-exercise increase in the level of TAC. Post-exercise changes in UA concentration were insignificant. Post-exercise changes in TOC in men depended on the absolute values of VO2max , on VO2max/LBM, and on post-exercise changes in La- concentration., M. Wiecek, M. Maciejczyk, J. Szymura, Z. Szygula., and Obsahuje bibliografii
In this study, we investigated the effects of Nw -nitro-L-arginine (L-NNA) on arterial blood pressure (BP), plasma noradrenaline (NA) and adrenaline (A) levels and angiotensin-converting enzyme (ACE) activity. L-NNA was applied with tap water (1 mg/ml) from the 3rd to the 8th week of age (group L-NNA1). In Experiment 1, long-term L-NNA application increased BP compared to the control group (group C1) (L-NNA1 = 131.4 ± 6.3, n=6; C1= 82.7 ± 4.7 mm Hg, n=7) but decreased plasma noradrenaline and adrenaline levels and ACE activity (NA levels: C1 = 15.5 ± 0.8, n=7; L-NNA1= 8,6 ± 0.5 ng/ml, n=7; A levels: C1 = 15.5 ± 0.8, n=7; L-NNA1 = 6.0 ± 0.5 ng/ml, n=7; ACE activities: C1= 87.3 ± 3.1, n=6; L-NNA1 = 46.2 ± 1.9 U/l, n=5). On the other hand, in Experiment 2 (carried out under the same conditions and in age-matched chickens), blood pressure, plasma noradrenaline levels and ACE activity were found to differ in the control group (C2) (BP=141.4 ± 15.5 mm Hg, n=7; NA =1.1 ± 0.4 ng/ml, n=7; ACE = 57.2 ± 5.3 U/l, n=7) as compared to C1, while plasma adrenaline levels were similar. In this series, long-term L-NNA application (group L-NNA2) did not change the BP, but surprisingly increased noradrenaline and ACE values (values of L-NNA2: BP = 165.7 ± 15.6 mm Hg, n=7; NA = 9.3 ± 1.3 ng/ml, n=8; ACE = 149.4 ± 16 U/l, n=8) while decreasing plasma adrenaline levels. L-arginine addition to L-NNA treatment completely reversed plasma noradrenaline and ACE activity values. These results indicate the modulatory activity of an L-arginine-NO pathway on adrenaline release as well as on the renin-angiotensin system in chickens., H. E. Aksulu, I. Bingöl, F. Karatas, H. Sagmanligil, B. Üstündag., and Obsahuje bibliografii
Hypoxic pulmonary vasoconstriction (HPV) occurs in smooth muscle cells (SMC) from small pulmonary arteries (SPA) and is accompanied by increases in free cytoplasmic calcium ([Ca2+]i) and cytoplasmic pH (pHi). SMC from large pulmonary arteries (LPA) relax during hypoxia, and [Ca2+]i and pHi decrease. Increases in pHi and [Ca2+]i in cat SPA SMC during hypoxia and the augmentation of hypoxic pulmonary vasoconstriction by alkalosis seen in isolated arteries and lungs suggest that cellular mechanisms, which regulate inward and outward movement of Ca2+ and H+, may participate in the generation of HPV. SMC transport systems that regulate pHi include the Na+-H+ transporter which regulates intracellular Na+ and H+ and aids in recovery from acid loads, and the Na+-dependent and Na+-independent Cl-/HCO3- transporters which regulate intracellular chloride. The Na+-dependent Cl-/HCO3- transporter also aids in recovery from acidosis in the presence of CO2 and HCO3-. The Na+-independent Cl-/HCO3- transporter aids in recovery from cellular alkalosis. The Na+-H+ transporter was present in SMC from SPA and LPA of the cat, but it seemed to have little if any role in regulating pHi in the presence of CO2 and HCO3-. Inhibiting the Cl-/HCO3- transporters reversed the normal direction of pHi change during hypoxia, suggesting a role for these transporters in the hypoxic response. Future studies to determine the interaction between pHi, [Ca2+]i and HPV should ascertain whether pHi and [Ca2+]i changes are linked and how they may interact to promote or inhibit SMC contraction., J. A. Madden, P. A. Keller, J. G. Kleinman., and Obsahuje bibliografii
The role of the cortico-tectal pathways in the processing of auditory signals was investigated by recording the click-evoked responses and extracellular multiple unit activity in the inferior colliculus (IC) after functional ablation of the auditory cortex (AC) by local intracortical application of a sodium channel blocker, tetrodotoxin (TTX). Click-evoked IC responses (IC-ER) and multiple unit activity in response to tone bursts were recorded with implanted electrodes in the IC of rats lightly anaesthetized with xylazine. Neural activity was recorded before and after the application of TTX into the ipsilateral auditory cortex (AC) through three implanted cannulas in a total dose of 30 ng. The functional status of the AC was monitored by recording click-evoked middle latency responses from a ball electrode implanted on the AC. During inactivation of the AC, IC-ER amplitudes were either increased (48 % of the cases), decreased (32 % of the cases) or not evidently changed (20 % of the cases). Corresponding effects were observed in the firing rate of IC neurons. Functional ablation of the AC also resulted in a significant prolongation of the latencies of individual waves of the IC-ER. However, the discharge pattern of the multiple unit responses, response thresholds and tuning were not altered during AC inactivation. IC neural activity recovered within several hours, and maximally during 2 days. The results reveal principles of the interaction of cortico-tectal pathways with IC neuronal activity., F. C. Nwabueze-Ogbo, J. Popelář, J. Syka., and Obsahuje bibliografii
Postnatal heart development is characterized by critical periods of heart remodeling. In order to characterize the changes in the lipophilic fraction induced by free radicals, fatty acids and t heir oxidized products, lipofuscin -like pigments (LFP), were investigated. Fatty acids were analyz ed by gas chromatography and LFP were studied by fluorescence techniques. A fluorophore characterized by spectral methods was further resolved by HPLC. Major changes in the composition of fatty acids occurred immediately after birth and then during maturation. Fluorescence of LFP changed markedly on postnatal days 1, 4, 8, and 14, and differed from the adult animals. LFP comprise several fluorophores that were present since fetal state till adulthood. No new major fluorophores were formed during development, just the abundances of individual fluorophores have been modulated which produced changes in the shape of the spectral arrays. HPLC resolved the fluorophore with excitation maximum at 360 nm and emission maximum at 410 nm. New chromatographically distinct species appeared immediately on postnatal day 1, and then on days 30 and 60. Consumption of polyunsaturated fatty acids immediately after birth and subseque nt formation of LFP suggests that oxidative stress is involved in normal heart development., J. Wilhelm, J. Ivica, Z. Veselská, J. Uhlík, L. Vajner., and Obsahuje bibliografii
Nitric oxide (NO) may play a role in the pathophysiology of excitotoxicity. It is also possible that increase in Ca2+ overload and NO-mediated events are involved in neuronal loss during excitotoxicity. Using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, we have investigated the effects of melatonin on NADPH-d positive hippocampal neurons after kainic acid (KA) induced excitotoxicity in female rats of Wistar strain. Cytosolic Ca2+ (free calcium) in all the respective experimental groups was also studied. Kainic acid was administered, with a single dose of 10 mg/kg/bw (body weight) to the animals. KA treated rats were given melatonin at a dose of 20 mg/kg/bw (for 14 day). On the last day of treatment, animals were transcardially perfused with 4 % paraformaldehyde under deep thiopental anaesthesia. Cryostat sections (20 µm) were cut and stained for NADPH-d positive neurons. KA exposed animals showed a significantly increased number of NADPH-d positive neurons in the dorsal and ventral blade of the dentate gyrus (DG), hilus, CA1 and CA3 area of hippocampus, with a parallel increase in intracellular free Ca2+ ion concentration, as compared to the control group. KA + melatonin-treated animal groups showed reduced number of NADPH-d positive neurons in DG, hilus, CA1 and CA3 areas and a decline in cytosolic Ca2+ concentration, as compared to KA treated group. Our study suggests that the enhanced levels of cytosolic Ca2+ and nitric oxide (NO) play an important role in kainate induced excitotoxicity. Inhibition of NO production may be another means whereby melatonin can reduce oxidative damage and seems to play important role in neuroprotection., A. Jain, ... [et al.]., and Obsahuje seznam literatury
Free radicals and proinflammatory cytokines from phagocytes have been implicated in the pathogenesis of endotoxic shock, a disease with high mortality caused by Gram-negative bacterial endotoxin. In the present study, male BALB/c and Swiss mice received intraperitoneally lipopolysaccharide (LPS) at 100 mg/kg and 150 mg/kg, respectively, that led to a lethal endotoxic shock (100 % of mortality before 30 h). Swiss mice injected with 100 mg/kg, that did not show lethal endotoxic shock, were also studied. Peritoneal macrophages were obtained from animals at 2, 4, 12 or 24 h after injection of LPS or saline (control) solutions. Superoxide anion and tumor necrosis factor (TNFα) production were determined in these cells as well as other functions such as adherence capacity, chemotaxis and phagocytosis. The increase in superoxide anion production after endotoxin injection was higher in cells from mice with lethal shock than in those with non-lethal shock. However, the enhancement of TNFα production was similar in all cases, although in Swiss mice the highest levels of TNFα were observed at 1.5 h after endotoxin injection, while in BALB/c mice they occurred at 2 h after LPS injection. This oxidative stress was also revealed by the other functions analyzed, since adherence to substrate and phagocytosis were stimulated and chemotaxis was decreased after endotoxin injection as compared to controls, the differences being even more significant in animals with lethal shock. These data suggest that these changes, mainly the increased production of free radicals even more than the TNFα release, could be involved in mouse mortality caused by LPS., V. M. Víctor, M. de la Fuente., and Obsahuje bibliografii
Quantitative and qualitative changes of serum proteins, apart from glycation, have not been sufficiently studied in streptozotocin-induced diabetic rats (D), the most common experimental model for diabetes. Thus, we decided to analyze the serum of diabetic rats by concanavalin A-blotting in comparison with rats with acute inflammation induced by fermented yeast (Y), in which characteristic alterations of serum proteins have been described. Two months after the streptozotocin treatment, the blood glucose levels were highly elevated (456± 24 vs. 124± 10 mg/dl, p<0.001, n=12), the body weight was significantly lower than normal (279± 10 vs. 392± 6 g, p<0.001, n=12), and serum proteins appeared to be highly glycated (p<0.001) when analyzed by the fructosamine assay, without any significant change in the total serum protein concentration. Analysis by concanavalin A-blotting, revealed a significant decrease of a1-inhibitor-3 (a1-I3, p<0.05) and an increase of the b chain of haptoglobin (b-Hp, p<0.05) in both D and Y rats (n=3) compared with control animals. However, acute inflammation caused a marked rise of two prominent acute phase proteins, a2-macroglobulin and hemopexin, which did not change appreciably in diabetic rats. Further work will be necessary to evaluate the physiopathological significance of these phenomena which could result from changes of both concentration and glycosylation of the aforementioned proteins., L. Saso, P. Tommasino, G. Italiano, E. Grippa, M.G. Leone, M.T. Gatto, B. Silvestrini., and Obsahuje bibliografii