Maghemite (γ-Fe2O3) nanoparticles, 12 nm in size, were prepared by co-precipitation of Fe(II) and Fe(III) chlorides with ammonium hydroxide and oxidation with hydrogen peroxide. To achieve stability and biocompatibility, obtained particles were coated with silica, to which glucose and ascorbic acid were bound by different mechanisms. The composite particles were thoroughly characterized by transmission electron microscopy, dynamic light scattering, elemental analysis, and FT-Raman and fluorescence spectroscopy to determine composition, morphology, size and its distribution, ζ-potential, and scavenging of peroxyl and hydroxyl radicals. As the particles showed promising antioxidative properties, they may have a possible application as a stable magnetically controlled scavenger of reactive oxygen species., M. Moskvin, D. Horák., and Obsahuje bibliografii
Carcinopodacarus polymorphus gen. n. et sp. n. (Acariformes: Dermationidae: Dermationinae) is described from the guira cuckoo Guira guira (Gmelin) (Cuculiformes: Cuculidae) in Brazil. The new genus differs from the closest genus, Psittophagoides Fain, 1964, by the following features: in both sexes, the anterior spines of trochanters I and II are absent (vs present in Psittophagoides), setae d2 are distinctly developed (vs only alveoli), and genual setae mGI are absent (vs present); in males, the hysteronotal shield is split transversally at the level of trochanters III (vs hysteronotal shield entire); in females, the platelets situated posterior to the propodonotal shield are absent (vs present), the metapodosomal sclerites are present (vs absent), and the adanal shields are fused anteriorly to each other (vs separated from each other). In this species, andropolymorphism is detected for the first time for the family. It involves various characters but the most impressive feature is the structure of legs III. In hetero- and mesomorphic males, these legs are strongly hypertrophied and have a distinct ventral spur on femora III; in homeomorphic males, legs III are not modified and subequal to legs IV., Fabio Akashi Hernandes, Luiz Gustavo A. Pedroso, Andre V. Bochkov., and Obsahuje bibliografii
AT1 receptor (AT1R) blockade prevents physiological cardiac hypertrophy induced by resistance training. Also, our group showed that a single bout of resistance exercise (RE) activates the AKT/mTOR which was also inhibited by AT1R blocker. Here, we investigated whether IGF1-receptor (IGF1-R) and MAPKs were also activated after a single bout of RE. Wistar rats were divided into Sedentary (Sed), Sedentary treated with losartan (Sed+LOS), Exercise (EX), and Exercise treated with losartan (EX+LOS). Cardiac tissue was obtained 5 and 30 min after 4 sets of 12 repetitions of squat exercise (80 % 1RM). We demonstrated that a single bout of RE did not induce IGF1-R tyrosine phosphorylation. ERK1/2 and P38 phosphorylation levels were elevated in the EX 5min and EX 30min groups however, only ERK1/2 was inhibited by losartan treatment (AT1R blocker). Next, we showed that β-arrestin-2 expression increased 28 % in trained animals compared to sedentary group. Altogether, our results demonstrate that AT1R, but not IGF1-R, may exert the hypertrophic cardiac stimulus RE-induced. Also, activation of AKT/mTOR and ERK1/2 pathways may occur through the
β-arrestin-dependent pathway.
Thyroid hormones are powerful modulators of heart function and susceptibility to arrhythmias via both genomic and non-genomic actions. We aimed to explore expression of electrical coupling protein connexin-43 (Cx43) in the heart of rats with altered thyroid status and impact of omega-3 polyunsaturated fatty acids (omega-3) supplementation. Adult male Lewis rats were divided into following six groups: euthyroid controls, hyperthyroid (treated with T3) and hypothyroid (treated with methimazol) with or without six-weeks lasting supplementation with omega-3 (20 mg/100 g/day). Left and right ventricles, septum and atria were used for immunoblotting of Cx43 and protein kinase C (PKC). Total expression of Cx43 and its phosphorylated forms were significantly increased in all heart regions of hypothyroid rats compared to euthyroid controls. In contrast, the total levels of Cx43 and its functional phosphorylated forms were decreased in atria and left ventricle of hyperthyroid rats. In parallel, the expression of PKC epsilon that phosphorylates Cx43, at serine 368, was increased in hypothyroid but decreased in hyperthyroid rat hearts. Omega-3 intake did not significantly affect either Cx43 or PKC epsilon alterations. In conclusion, there is an inverse relationship between expression of cardiac Cx43 and the levels of circulating thyroid hormones. It appears that increased propensity of hyperthyroid while decreased of hypothyroid individuals to malignant arrhythmias may be in part attributed to the changes in myocardial Cx43., B. Szeiffová Bačová, T. Egan Beňová, C. Viczenczová, T. Soukup, H. Rauchová, S. Pavelka, V. Knezl, M. Barančík, N. Tribulová., and Obsahuje bibliografii
Hypothermic incubation of chicken eggs leads to smaller embryos with enlarged hearts, originally described as hypertrophic. Over the years, however, accumulated evidence suggested that hyperplasia, rather than hypertrophy, is the predominant mechanism of cardiac growth during the prenatal period. We have thus set to reevaluate the hypothermia model to precise the exact cellular mechanism behind cardiac enlargement. Fertilized chicken eggs were incubated at either 37.5 °C (normothermia) or 33.5 °C from embryonic day (ED) 13 onward (hypothermia). Sampling was performed at ED17, at which point wet embryo and heart weight were recorded, and the hearts were submitted to histological examination. In agreement with previous results, the hypothermic embryos were 29% smaller and had hearts 18% larger, translating into a 67% increase in the heart to body weight ratio (P < 0.05 for all parameters). The cell size was essentially the same between control and hypothermic hearts in all regions analysed. Likewise, there was no significant relationship between the cell size and heart weight; however, in the hypothermic hearts, there was a trend showing positive correlation between cell sizes in different cardiac regions and heart weight. Proliferation rate, determined on the basis of anti-phosphohistone H3 immunofluorescence, showed an overall increase in the hypothermic group, reaching statistical significance (P = 0.02, t-test) in the right ventricle. The proliferation rate was similar among different regions of the same heart. However, the correlation between the proliferation rate and heart weight was only small (r2 = 0.007 and r2 = 0.234 for the normothermic and hypothermic group, respectively). We thus
conclude that hyperplasia is the predominant response mechanism in this volume-overload model; mechanistically, decreased heart rate at lower temperature increases the end-diastolic and stroke volume, minimizing the drop in cardiac output through the Frank-Starling mechanism. and Corresponding author: David Sedmera
Our aim was to evaluate whether endothelial overexpressing of the bradykinin B1 receptor could be associated with altered left ventricular and myocardial performance. Echocardiography and hemodynamic were employed to assess left ventricular morphology and function in Sprague Dawley transgenic rats overexpressing the endothelial bradykinin B1 receptor (Tie2B1 rats). The myocardial inotropism was evaluated on papillary muscles contracting in vitro. In Tie2B1 animals, an enlarged left ventricular cavity and lower fractional shortening coupled with a lower rate of pressure change values indicated depressed left ventricular performance. Papillary muscle mechanics revealed that both Tie2B1 and wild-type rat groups had the same contractile capacities under basal conditions;
however, in transgenic animals, there was accentuated inotropism due to post-pause potentiation. Following treatment with the Arg9-BK agonist, Tie2B1 papillary muscles displayed a reduction in myocardial inotropism. Endothelial B1 receptor overexpression has expanded the LV cavity and worsened its function. There was an exacerbated response of papillary muscle in vitro to a prolonged resting pause, and the use of a B1 receptor agonist impairs myocardial inotropism.
More than four decades passed since sigma receptors were first
mentioned. Since then, existence of at least two receptor
subtypes and their tissue distributions have been proposed.
Nowadays, it is clear, that sigma receptors are unique ubiquitous
proteins with pluripotent function, which can interact with so
many different classes of proteins. As the endoplasmic resident
proteins, they work as molecular chaperones - accompany
various proteins during their folding, ensure trafficking of the
maturated proteins between cellular organelles and regulate their
functions. In the heart, sigma receptor type 1 is more dominant.
Cardiac sigma 1 receptors regulate response to endoplasmic
reticulum stress, modulates calcium signaling in cardiomyocyte
and can affect function of voltage-gated ion channels. They
contributed in pathophysiology of cardiac hypertrophy, heart
failure and many other cardiovascular disorders. Therefore,
sigma receptors are potential novel targets for specific treatment
of cardiovascular diseases.
A topological space X has a rank 2-diagonal if there exists a diagonal sequence on X of rank 2, that is, there is a countable family {Un : n ∈ ω} of open covers of X such that for each x ∈ X, {x} = ∩ {St2 (x,Un): n ∈ ω}. We say that a space X satisfies the Discrete Countable Chain Condition (DCCC for short) if every discrete family of nonempty open subsets of X is countable. We mainly prove that if X is a DCCC normal space with a rank 2-diagonal, then the cardinality of X is at most c. Moreover, we prove that if X is a first countable DCCC normal space and has a Gδ-diagonal, then the cardinality of X is at most c.
For an uncountable monounary algebra $(A,f)$ with cardinality $\kappa $ it is proved that $(A,f)$ has exactly $2^{\kappa }$ retracts. The case when $(A,f)$ is countable is also dealt with.
The authors present the case of a young woman with newly diagnosed Takayasu’s arteritis. This woman, with arterial hypertension, was investigated for the unspecific symptoms at the beginning. Afterwards, the transthoracic echocardiography showed dysfunction of the left ventricle and the abdominal sonography showed a stenosis of the right renal artery. PET/CT scan showed chronic modification after inflammatory processes on the wall of the thoracic and abdominal aorta. This case report should be instructive to other clinicians and refers to the necessity to remember this rare disease in our country too., Lucie Horáková, Radek Pudil, Zbyněk Hrnčíř, Jaroslav Vižďa, and Literatura 8