Angiotensin converting enzyme (ACE) inhibition has been reported to induce regression of hypertrophy in several models of hemodynamic pressure overload. The aim of the present study was to determine whether the ACE inhibitor captopril can reduce hypertrophy of the left ventricle induced by a chronic volume overload and modify collagen composition of the hypertrophied myocardium. Rabbits with four months lasting aortic insufficiency were divided into two groups: treated with captopril (20 mg/kg/day) for five weeks and treated with placebo. The respective control groups were represented by sham-operated animals. Aortic insufficiency induced a decrease of diastolic pressure, an increase of systolic and pulse pressure, hypertrophy of the left and right ventricle, and an increase of hydroxyproline content in the left ventricle without a change of hydroxyproline concentrations in either ventricle. Captopril treatment further enhanced pulse pressure by decreasing diastolic blood pressure. Hypertrophy of the left ventricle, hydroxyproline content and concentration in both ventricles were unaffected by captopril treatment. It is concluded that ACE inhibition did not reverse the left ventricular hypertrophy developed as a result of overload induced by aortic insufficiency. We suggest that mechanisms different from activation of the renin-angiotensin system may play a decisive role in the maintenance of hypertrophy in this particular model of volume hemodynamic overload., F. Šimko, V. Pelouch, J. Kyselovic., and Obsahuje bibliografii
We studied the effects of the H2S donor Na2S on the mean arterial blood pressure (MAP) and heart and breathing rates of anesthetized Wistar rats in the presence and absence of captopril. Bolus administration of Na2S (1-4 μmol/kg) into the right jugular vein transiently decreased heart and increased breathing rates; at 8-30 μmol/kg, Na2S had a biphasic effect, transiently decreasing and increasing MAP, while transiently decreasing heart rate and increasing and decreasing breathing rate. These results may indicate independent mechanisms by which H2S influences MAP and heart and breathing rates. The effect of Na2S in decreasing MAP was less pronounced in the presence of captopril (2 μmol/l), which may indicate that the renin-angiotensin system is partially involved in the Na2S effect. Captopril decreased H2S-induced NO release from S-nitrosoglutathione, which may be related to some biological activities of H2S. These results contribute to the understanding of the effects of H2S on the cardiovascular system., M. Drobná, A. Misak, T. Holland, F. Kristek, M. Grman, L. Tomasova, A. Berenyiova, S. Cacanyiova, K. Ondrias., and Obsahuje bibliografii
The aim of the study was to assess whether angiotensin converting enzyme (ACE) inhibition with captopril prevents the development of hypertension and myocardial hypertrophy and affects nitric oxide synthase (NOS) activity in rats. Animals were divided into five groups: control, two groups receiving NG-nitro-L-arginine methyl ester (L-NAME) 20 or 40 mg/kg/day, a group receiving captopril 100 mg/kg/day and a group concomitantly treated with 40 mg/kg/day L-NAME plus 100 mg/kg/day captopril. After four weeks, systolic blood pressure (SBP) significantly increased in both L-NAME groups by 30 % and 34 %, respectively. In the captopril group, SBP significantly decreased by 30 % and in the captopril plus L-NAME group SBP was not changed as compared to the controL Although left ventricular weight/body weight (LVW/BW) ratio in both L-NAME groups was significantly elevated by 19 % and 29 %, respectively, no alterations in LVW/BW ratio were found in the captopril group and captopril plus L-NAME group. In both groups receiving L-NAME, NOS activity significantly decreased by 17 % and 69 % in the heart, by 14 % and 26 % in the aorta, by 60 % and 73 % in the brain and by 13 % and 30 % in the kidney, respectively. Captopril did not influence NO synthase activity in any of the studied tissues. We conclude that captopril prevents the development of hypertension and LV hypertrophy without affecting NO formation.
The operator is required to be constantly vigilant and even more attentive when operating the device. The paper introduces a cooperation of a car simulator realized in the virtual reality (VR) environments and measurements of "human driver behavior" focused mainly on the aspects of HMI and drivers' attention decrease. In the first part a conception and a development of our VR car simulation devices are described. During the development of the car simulators many problems need to be solved. One of these problems is represented by a simplification and a partial automation of a scenery creation. The first part is dedicated to the algorithms used in our tools, which help to automate the creation of virtual scenes. The next part analyses, in greater detail, the tools themselves and the rest of this section deals with demonstration of the scenes, which were modeled using these tools. For simpler and faster generation of virtual sceneries it is suitable to store the models within a hierarchical database 3D object. Our database includes model objects from which it subsequently forms surroundings for the road virtual scenes. In the article is described how to specify the 3D model properties - their fundamental characteristic and consequent differentiation into specific categories. Sound perception cues are one of the most important ones besides the visual cues in the car simulation. The audio section of this article deals with simulating a sound of a car engine as a most significant audio stimulant for the driver. It shows the basics of the cross fading system which renders the car audio from multiple looped samples. The first part contains an analysis of car engine sound, the second part describes how to synthesize it on the computer. Validation measurements and consequent results are shown at the end of this section. The final paragraphs show examples of experiments developed for measurements of the driver's fatigue and other aspects of the driver's behavior.
This paper presents the idea of using two-dimensional geographical
data as a base for building a more realistic three-dimensional Virtual scene. The background of the geographical Information system (GIS) and its stay of art is discussed here. Then a framework architecture with description of system blocks and their functions to realize two to three dimensional transformation is defined here.
Golf is a popular sport, with increasingly large areas of urban and peri-urban land being designated for golf course development. Yet, more than half of the land area of a typical golf course is considered rough and out-of-play areas that can, if managed appropriately, provide habitats for wildlife. Using pitfall traps, 6944 carabid beetles belonging to 72 species were collected from five urban golf courses and three areas designated for golf course development around the city of Helsinki, Finland in 2007. The courses were rich in carabid species and distinct in their species assemblages. Golf courses were dominated by habitat generalists, species capable of flight and medium to large-sized species. The three courses with areas designated for further golf course development showed that the assemblages of beetles associated with these golf courses have retained many elements from the pre-existing habitats. The oldest golf course is characterised by a more evenly distributed and diverse carabid beetle assemblage, probably due to its higher habitat heterogeneity and longer successional development. However, even this golf course is dominated by generalist species, implying that golf courses may not provide suitable habitats for specialists. It is assumed that the high species richness of golf courses is attributed to the high habitat diversity of these environments, ranging from the strongly human-modified to more natural patches, which provide habitats for many generalist and open-habitat species. Golf courses may, however, with the appropriate management of out-of-play areas provide an opportunity for conserving biodiversity.
We examined the occurrence of carabid beetles (Coleoptera, Carabidae) at the edges of oak (Quercus pyrenaica) and beech (Fagus sylvatica) forests in León, NW Spain. Pitfall traps were used to collect beetles from April to October 2002, and leaf litter cover and depth were measured. Traps were placed at three distances (0, 50 and 100 m) from the edges of eight forest patches. A total of 5436 carabids belonging to 43 species were collected. We found no statistically significant edge effect at the carabid assemblage level, i.e. the number of species and individuals was not higher at the edge compared to the forest interior. However, individual species were affected by distance from the edge. Five of the 14 species analysed responded predictably to the edge, three of them statistically significantly so. Four species did not respond in the predicted direction, two of them statistically significantly so. We found a considerable difference between forest types in terms of carabid assemblage composition and response to the edge. Oak forests were species richer and beech forests had a higher number of individuals. These differences were probably due to small-scale habitat heterogeneity in the oak forest patches, caused by man, and the homogeneous structure of beech forests. Leaf litter appeared to be one possible factor influencing the distribution of some species from the interior to the edge of forests.
I review the effects of habitat fragmentation on carabid beetles (Coleoptera, Carabidae) and examine whether the taxon could be used as an indicator of fragmentation. Related to this, I study the conservation needs of carabids. The reviewed studies showed that habitat fragmentation affects carabid assemblages. Many species that require habitat types found in interiors of fragments are threatened by fragmentation. On the other hand, the species composition of small fragments of habitat (up to a few hectares) is often altered by species invading from the surroundings. Recommendations for mitigating these adverse effects include maintenance of large habitat patches and connections between them. Furthermore, landscape homogenisation should be avoided by maintaining heterogeneity of habitat types. It appears that at least in the Northern Hemisphere there is enough data about carabids for them to be fruitfully used to signal changes in land use practices. Many carabid species have been classified as threatened. Maintenance of the red-listed carabids in the landscape requires species-specific or assemblage-specific measures.