b1_Essential hypertension is a multifactorial disorder which belongs to the main risk factors responsible for renal and cardiovascular complications. This review is focused on the experimental research of neural and vascular mechanisms involved in the high blood pressure control. The attention is paid to the abnormalities in the regulation of sympathetic nervous system activity and adrenoceptor alterations as well as the changes of membrane and intracellular processes in the vascular smooth muscle cells of spontaneously hypertensive rats. These abnormalities lead to increased vascular tone arising from altered regulation of calcium influx through L-VDCC channels, which has a crucial role for excitation-contraction coupling, as well as for so-called “calcium sensitization” mediated by the RhoA/Rho-kinase pathway. Regulation of both pathways is dependent on the complex interplay of various vasodilator and vasoconstrictor stimuli. Two major antagonistic players in th e regulation of blood pressure, i.e. sympathetic nervous system (by stimulation of adrenoceptors coupled to stimulatory and inhibitory G proteins) and nitric oxide (by cGMP signaling pathway), elicit their actions via the control of calcium influx through L-VDCC. However, L-type calcium current can also be regulated by the changes in membrane potential elicited by the activation of potassium channels, the impaired function of which was detected in hypertensive animals. The dominant role of enhanced calcium influx in the pathogenesis of high blood pressure of genetically hypertensive animals is confirmed not only by therapeutic efficacy of calcium antagonists but especially by the absence of hypertension in animals in which L-type calcium current was diminished by pertussis toxin-induced inactivation of inhibitory G proteins., b2_ there is considerable information on th e complex neural and vascular alterations in rats with established hypertension, the detailed description of their appearance during the induction of hypertension is still missing., M. Pintérová, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
Prolonged exposure to alveolar hypoxia induces physiological changes in the pulmonary vasculature that result in the development of pulmonary hypertension. A hallmark of hypoxic pulmonary hypertension is an increase in vasomotor tone. In vivo, pulmonary arterial smooth muscle cell contraction is influenced by vasoconstrictor and vasodilator factors secreted from the endothelium, lung parenchyma and in the circulation. During chronic hypoxia, production of vasoconstrictors such as endothelin-1and angiotensin II is enhanced locally in the lung, while synthesis of vasodilators may be reduced. Altered reactivity to these vasoactive agonists is another physiological consequence of chronic exposure to hypoxia. Enhanced contraction in response to endothelin-1 and angiotensin II, as well as depressed vasodilation in response to endothelium-derived vasodilators, has been documented in models of hypoxic pulmonary hypertension. Chronic hypoxia may also have direct effects on pulmonary vascular smooth muscle cells, modulating receptor population, ion channel activity or signal transduction pathways. Following prolonged hypoxic exposure, pulmonary vascular smooth muscle exhibits alterations in K+ current, membrane depolarization, elevation in resting cytosolic calcium and changes in signal transduction pathways. These changes in the electrophysiological parameters of pulmonary vascular smooth muscle cells are likely associated with an increase in basal tone. Thus, hypoxia-induced modifications in pulmonary arterial myocyte function, changes in synthesis of vasoactive factors and altered vasoresponsiveness to these agents may shift the environment in the lung to one of contraction instead of relaxation, resulting in increased pulmonary vascular resistance and elevated pulmonary arterial pressure., L. A. Shimoda, J. S. K. Sham, J. T. Sylvester., and Obsahuje bibliografii
Cities in socialist Czechoslovakia were meant to constitute the setting for an ideal socialist society. The dogmatic embracement of this objective by the ruling Communist Party eventuated in complete intolerance towards any manifestation of free-thinking of alleged opposition to socialism. Starting in the 1960s, part od Czechoslovak youth were inspired by the Western countercultural hippie movement and the Beat generation, as well as by punk subculture beginning in the 1970s. These people openly displayed their alienation from the official cultury by disrupting the established societal standards of appearance, behaviour, and leisure activities.
The multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae) may potentially exploit a range of "alternative" food sources. The nutritional value of three common non-prey food groups, i.e. fruit, fungi and pollen, is examined in this study. Development, reproduction and survival of the species were assessed in the laboratory on diets of apple, pear and raspberries and the fungi Oidium lycopersicum, Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani. When fed exclusively on these foods this ladybird failed to complete its development or reproduce. However, larval and adult survival was prolonged by 4 to 8 days and 55 to 67 days, respectively, when fruit was offered compared with only water. During a field study H. axyridis adults were collected monthly from March to October at two locations near Ghent, Belgium. Gut analysis demonstrated that, despite the continued presence of aphids, over 90% of all the adults collected contained pollen throughout the year. The pollen belonged to 53 different pollen types. Monthly average numbers of pollen grains in the gut varied from 5 to 233 grains. In contrast, there were about 35,000 grains in the guts of H. axyridis females that successfully developed and reproduced in the laboratory on diet that consisted of only pollen. This suggests that in the field in the majority of cases pollinivory mainly only provided complementary nutrients for this coccinellid. The use of alternative non-prey foods like pollen and fruit may play a role in sustaining populations of this coccinellid at times when the optimal prey is absent.
Jewish politics of the first half of the 20th century can hardly be reduced to the history of the Zionist movement. Various autonomy oriented groupings were obviously active as well, with the so-called “Bund” being one of the most prominent among them. Although the demand for Jewish national and cultural autonomy in the Diaspora, particularly in Eastern Europe, and the emphasis upon cultivation of the Yiddish culture could be seen as two characteristic features of the Bund, the very evolution of these notions attests to a rather more complex mosaic of the Bundist world outlook.
We reviewed the distribution of Robertsonian (Rb) races of Mus musculus domesticus in central and southern Italy. This Rb system is called the Apennine system and includes four races (Cittaducale, ICDE, 2n=22; Ancarano, IACR, 2n=24; Campobasso, ICBO, 2n=22; Colfiorito, ICOL, 2n=33–34) surrounded by standard populations with karyotype 2n=40. Here we evaluate the relationships between the altitudinal distribution of races, and the indoor vs. outdoor behaviour of populations, inferred from literature data on the diet of the barn owl Tyto alba. We assume that a higher prevalence of mice in owl pellets reflects a higher outdoor occurrence of mice. The IACR and ICDE races were found at higher altitudes than the standard populations, while the ICBO race is present at lower altitudes like the standard race. The standard race has indoor and outdoor populations; in all the Rb races an indoor life has been suggested by our data. This behaviour is only partly due to altitude, since the ICBO race also lives at sea level. We speculated that indoor life is an intrinsic characteristic of the ICBO race irrespective of the environment. This pattern reinforces the idea that indoor life, through its population dynamics, has played a significant role in the evolutionary history of Rb races.
The relationship between species richness of plants and animals and altitude can be either hump-shaped, a monotonic decrease or increase. In this study the altitudinal distribution of moths on one of the highest mountains in South Korea was investigated. Moths were captured using a UV-light trap from May to October in 2007 and 2008. This revealed that the relationship between the total numbers of moth species and individuals and altitude is hump-shaped. A significant relationship was also recorded between the size of the area at each altitude and moth abundance and richness. However, the evenness index yielded a consistent decrease with increase in altitude because of the dominance of few species at high altitudes. Non-metric multidimensional scaling identified two major axes for the moth assemblage on Mount Jirisan. The correlations between the axes and variables demonstrated that the first axis was strongly correlated with altitude and aspect and the second axis with forest and site location.