Domoic acid (DA) is a potent marine neurotoxine present in seafood. Intoxication by DA causes gastrointestinal symptoms like vomiting and diarrhoea and also the so-called amnesic shellfish poisoning (inflicting memory impairment and seizures). Since exposure to non-convulsive doses is relevant to the human health, we investigated the effect of low dose DA administration in adult Wistar rats. Rats were administered with DA at the dose 1.0 mg/kg and their behavior was monitored for one hour in three sessions. The first session started immediately after DA administration. The second and third session started one and two weeks later. After the third session, the histochemical analysis of the hippocampi of the animals was conducted (Fluoro-Jade B, bis-benzimide). DA increased time spent by locomotion and distance travelled in the second half of the first session and this effect was pronounced during the second and third session. Exploratory rearing was decreased by DA administration in the first half of the first session. DA influenced the grooming in biphasic manner (decrease followed by an increase of time spent by grooming). This biphasic trend was observed even two weeks after the DA administration. Histochemistry of DA treated rats did not confirm the presence of apoptotic bodies, Fluoro-Jade B positive cells were not found neither in CA1 nor CA3 area of the hippocampi. Our study revealed that a low dose of DA affect short and long-term the spontaneous behavior of rats without inducing neuronal damage., M. Schwarz, K. Jandová, I. Struk, D. Marešová, J. Pokorný, V. Riljak., and Obsahuje bibliografii
The effects of soil and water contamination by lead (Pb) and the consequences on plant growth and yield are of great concern worldwide. Limits of the Pb concentration in water have been established by governmental institutions but these differ from each other. In this study, Lactuca sativa (var. Reine de Mai) plants were exposed to low Pb(NO3)2 doses (0.05-20 mg L-1), including the recommended limit values for irrigation water by the Food and Agriculture Organization (FAO). After 28 d of exposure, lettuce plants did not present visible morphological alterations or growth impairment, but CO2 assimilation rate (PN), photochemical quenching, and effective quantum efficiency of PSII were negatively affected, while intercellular CO2 concentration, stomatal conductance, or transpiration rate were not influenced. Our results suggested that limitations on photosynthesis occurred from different reasons than due to the decrease of internal CO2 availability, alterations of photophosphorylation, and/or electron transport rate. Thus, this lettuce cultivar showed photosynthetic susceptibility to low doses of Pb, even at lower concentrations than those maximal allowed for irrigation water by FAO. Furthermore, PN seemed to be the most sensitive biomarker for evaluation of Pb susceptibility., S. Silva, G. Pinto, C. Santos., and Obsahuje bibliografii
Low temperature phosphorescence, fluorescence and transient hole buming spectra of the photosystem 2 particles isolated from the cyanobacterium Synechococcus elongatus were measured. The role of photosynthetic activity was estimated by comparison of these spectroscopic methods. A model explaining chlorophyll fluorescence changes and both phosphorescence quantum efficiency increase and transient hole bimiing efficiency decrease connected with Chemical or heat photosynthetic deactivation is presented.
a1_The effect of low-salt diet on phospholipid composition and remodeling was examined in rat colon which represents a mineralocorticoid target tissue. To elucidate this question, male Wistar rats were fed a low-salt diet and drank distilled water (LS, low-salt group) or saline instead of water (HS, high-salt group) for 12 days before the phospholipid concentration and fatty acid composition of isolated colonocytes were examined. The dietary regimens significantly influenced the plasma concentration of aldosterone which was high in LS group and almost zero in HS group. Plasma concentration of corticosterone was unchanged. When expressed in terms of cellular protein content, a significantly higher concentration of phospholipids was found in LS group, with the exception of sphingomyelin (SM) and phosphatidylserine (PS). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounted for more than 70 % of total phospholipids in both groups. A comparison of phospholipid distribution in LS and HS groups demonstrated a higher percentage of PE and a small, but significant, decrease of PC and SM in LS group. The percentage of phosphatidylinositol (PI), PS and cardiolipin (CL) were not affected by mineralocorticoid treatment. With respect to the major phospholipids (PE, PC), a higher level of n-6 polyunsaturated fatty acids (PUFA) and lower levels of monounsaturated fatty acids were detected in PC of LS group. The increase of PUFA predominantly reflected an increase in arachidonic acid by 53%. In comparison to the HS group, oleic acid content was decreased in PC and PE isolated from colonocytes of the LS group. Our data indicate that alterations in phospholipid concentration and metabolism can be detected in rats with secondary hyperaldosteronism., a2_The changes in phospholipid concentration and their fatty acid composition during fully developed effect of low dietary Na+ intake may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function., L. Mrnka, O. Nováková, F. Novák, E. Tvrzická , J. Pácha., and Obsahuje bibliografii
Consider the n×n matrix with (i, j)’th entry gcd (i, j). Its largest eigenvalue \lambda _{n} and sum of entries s_{n} satisfy \lambda _{n} > s_{n}/n. Because sn cannot be expressed algebraically as a function of n, we underestimate it in several ways. In examples, we compare the bounds so obtained with one another and with a bound from S.Hong, R.Loewy (2004). We also conjecture that \lambda _{n} > 6\Pi ^{-2}n log n for all n. If n is large enough, this follows from F.Balatoni (1969)., Jorma K. Merikoski., and Obsahuje seznam literatury
Polyunsaturated omega-3 fatty acids ( ω-3 PUFA) are important components of cell membrane a ffecting its function and their deficiency is deleterious to health. We have previously shown that spontaneously hypertensive rats (SHR) are prone to life- threatening arrhythmias that are reduced by ω-3 PUFA intake. Purpose of this study was to explore plasma and red blood cells (RBC) profile of ω-3 and ω-6 PUFA as well as to determine ω-3 index, a risk factor for sudden cardiac death, in aged SHR and the effect of ω-3 PUFA intake. Male and female 12-month-old SHR and age-matched Wi star rats fed with ω-3 PUFA (200 mg/kg BW/day/2 month) were compared with untreated rats. Composition of ω-3 PUFA: alfa linolenic acid, eicosapentaenoic acid (EPA) and docosahexaen oic acid (DHA) as well as ω-6 PUFA: linoleic acid and arachidonic acid was analyzed by gas chromatography. Results showed sex- and strain-related differences of basal ω-3 and ω-6 PUFA levels in plasma and RBC as well as in response to ω-3 PUFA intake. Comparing to Wistar rats ω-3 index, expressed as a percentage of EPA+DHA of total fatty acids, was lower in SHR and it increased due to consumption of ω-3 PUFA. Findings support our hypothesis that lower ω-3 index may be also a marker of increased propensity of the hypertensive rat heart to malignant arrhythmias., B. Bačová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Hypokalemia as a typical feature of primary aldosteronism (PA) is associated with muscle weakness and could contribute to lower cardio pulmonary fitness. The aim of this study was to describe cardiopulmonary fitness and exercise blood pressure and their determinants during a symptom-limited exercise stress test in patients with PA. We performed a cross-sectional study of patients with confirmed PA who were included before adrenal vein sampling on whom a symptom-limited exercise stress test with expired gas analysis was performed. Patients were switched to the treatment with doxazosin and verapamil at least tw o weeks befor e the study. In 27 patients (17 male) the VO 2peak was 25.4± 6.0 ml/k g/min which corresponds to 80.8 ±18.9 % of Czech national norm. Linear regression analysis shows that VO 2peak de pends on doxazosin dose (DX) (p=0.001) and kal emia (p= 0.02): VO 2peak = 4.2 - 1.0 * DX + 7.6 * Ka lemia. Patients with higher doxazosin doses had a longer history of hypertension and had used more antihypertensives before examination, thus indicating that VO 2peak also depends on the severity of hypertension. In patients with PA, lower cardiopulmonary fitness depends inversely on the severity of hypertension and o n lower plasma potassium level., V. Tuka, M. Matoulek, T. Zelinka, J. Rosa, O. Petrák, O. Mikeš, Z. Krátká, B. Štrauch, R. Holaj, J. Widimský Jr., and Obsahuje bibliografii
In this study we compared the levels of interleukin (IL)-6, IL-8, IL-10 and tumor necrosis factor-α (TNF-α) in population samples characterized by a high or low level of self-reported depression. We measured serum IL-6, IL-8, IL-10 and TNF-α in two cohorts which differed in scoring on the Zung Self-Rating Depression Scale (ZSDS). The group with a high score in ZSDS (average SDS index = 62.9) was called DEP (n=27), the group with a low score in ZSDS (average SDS index = 29.9) was called NDEP (n=16). The groups did not significantly differ in age, waist circumference and body mass index. For the assessment of serum cytokine levels multiplex immunoanalytic xMAP(LUMINEX) technology was used. We found lower IL-6 in the DEP group (medians; DEP 4.08 pg/ml vs. NDEP 6.11 pg/ml) on the border of statistical significance in multiple regression analysis (p=0.049). Serum levels of all other studied cytokines were not significantly different (medians; IL-8: DEP 2.18 pg/ml vs. NDEP 2.61 pg/ml; IL-10: DEP 2.85 pg/ml vs. NDEP 2.94 pg/ml; TNF-α: DEP 2.32 pg/ml vs. NDEP 2.30 pg/ml). These results are in contradiction to the prevailing opinion that proinflammatory cytokine levels are elevated in people with symptoms of depression. and Obsahuje bibliografii a bibliografické odkazy
Arterial sites with low wall shear stress (WSS) are more prone to the development of atherosclerotic plaques, as was observed in carotid arteries in subjects with atherosclerosis risk factors. Type 2 diabetes mellitus (DM), hypertension, hyperlipidemia and other components of the metabolic syndrome, are associated with high risk for symptomatic cerebrovascular disease. It was shown by others that untreated type 2 DM is associated with lower WSS in common carotid arteries. However, the cardiovascular risk of type 2 DM could be modified by therapy. The aim of our study was to test the hypothesis that treated type 2 DM subjects with metabolic syndrome still have lower WSS in common carotid arteries than healthy controls. We enrolled 26 compensated DM subjects with metabolic syndrome, treated by metformin, statins and ACEI for more than 6 months, and 22 aged-comparable healthy controls. Wall shear rate (WSR) was used as a measure of WSS. A linear 3-11 MHz probe was used to measure blood velocity and internal diameter in the common carotid arteries. We compared observed values of WSR adjusted for age by ANCOVA. Wall shear rate was significantly lower in DM group than in control subjects: peak (systolic) values of wall shear rate were 410±130 s-1 vs. 487±111 s-1 (p<0.005). DM subjects had significantly lower WSR, because of both thinner lumen and slower blood flow velocities. Lower WSR was accompanied by higher IMT (0.73±0.12 mm vs. 0.64±0.11 mm, p<0.001). Treated subjects with compensated type 2 DM with metabolic syndrome still have atherogenic hemodynamic profile. These findings might help to understand faster progression of atherosclerosis in diabetic subjects with metabolic syndrome despite up-to-date medication., E. Chytilová ...[et al.]., and Obsahuje seznam literatury