The effect of immunomodulatory agents on reparation processes in the thymus was studied in mice injured by a single sublethal or lethal dose of ionizing radiation ranging between 6.5-9.5 Gy. Reparation of thymus weight was not influenced by pretreatment with immunomodulators. Furthermore, the morphological picture did not exhibit appreciable differences between non-protected and protected groups, except for greater proliferation of fibroblasts and macrophages in protected animals.
To investigate the significance of impaired insulin secretion on preimplantation embryo development, outbred ICR female mice received an injection of a single dose of streptozotocin 200 mg.kg-1 14-17 days before fertilization. Oocytes were collected 24-26 h after hCG injection. Morphological evaluation revealed a lower percentage of oocytes with second polar bodies from streptozotocin-treated females in comparison with controls. Furthermore, in this group the incidence of degenerated embryos significantly increased after 120 h in vitro cultivation. Insulin (5 U per 100 g b.w.) administered twice daily to streptozotocin-treated mice significantly improved the Embryonic development. Morphological analysis of oocyte maturation in streptozotocin-treated mice showed no significant differences in comparison with control mice. It could be concluded that marked changes in preimplantation embryo development were detected in outbred ICR mice after streptozotocin administration and this process was partly reversible by insulin treatment. Furthermore, it was shown that the process of fertilization was negatively influenced and that during in vitro cultivation the delayed effects of impaired insulin secretion resulted in an increase of embryo degeneration at the time following the third mitotic cleavage.
The present experiments were performed to evaluate if increased heart tissue concentration of fatty acids, specifically myristic, palmitic and palmitoleic acids that are believed to promote physiological heart growth, can attenuate the progression of unloading-induced cardiac atrophy in rats with healthy and failing hearts. Heterotopic abdominal heart transplantation (HTx) was used as a model for heart unloading. Cardiac atrophy was assessed from the ratio of the native- to-transplanted heart weight (HW). The degree of cardiac atrophy after HTx was determined on days 7, 14, 21 and 28 after HTx in recipients of either healthy or failing hearts. HTx of healthy hearts resulted in 23±3, 46±3, 48±4 and 46±4 % HW loss at the four time-points. HTx of the failing heart resulted in even greater HW losses, of 46±4, 58±3, 66±2 and 68±4 %, respectively (P<0.05). Activation of “fetal gene cardiac program” (e.g. beta myosin heavy chain gene expression) and “genes reflecting cardiac remodeling” (e.g. atrial natriuretic peptide gene expression) after HTx was greater in failing than in healthy hearts (P<0.05 each time). Exposure to isocaloric high sugar diet caused significant increases in fatty acid concentrations in healthy and in failing hearts. However, these increases were not associated with any change in the course of cardiac atrophy, similarly in healthy and post-HTx failing hearts. We conclude that increasing heart tissue concentrations of the fatty acids allegedly involved in heart growth does not attenuate the unloading-induced cardiac atrophy., M. Pokorný, I. Mrázová, J. Malý, J. Pirk, I. Netuka, Z. Vaňourková, Š. Doleželová, L. Červenková, H. Maxová, V. Melenovský, J. Šochman, J. Sadowski, L. Červenka., and Seznam literatury
Plants grown at low irradiance were fertilized with 0, 60, and 600 g m-3 NH4NO3 once every fortnight. Plants treated with high N concentrations showed an increased growth, producing longer and broader fronds with larger areas, and were darker green in colour. Nitrogen also increased the content of chlorophyll (Chl) and carotenoids per leaf area unit. Different N treatments did not affect the photosynthetic efficiency of photosystem 2, as reflected by the high values of Chl fluorescence kinetics Fv/Fm, ranging between 0.81 to 0.84, and Fv/F0 of 4.30 to 5.10. An increase in photochemical quenching (qP), accompanied by a decrease in non-photochemical quenching (qN), was observed in sporophytes fertilized with increased concentrations of NH4NO3. Nitrogen availability allowed sporophytes of Acrostichum aureum to become more established under natural conditions. and R. S. Pillai, B.-L. Ong.
Experimental activation of peritoneal macrophages by interferon gamma (IFN-γ) resulted in the inhibition of Encephalitozoon cuniculi replication. However, E. cuniculi could replicate either in a non-activated cell line of murine macrophages PMJ2-R or in IFN-γ-activated PMJ2-R cells. Moreover, activation with IFN-γ led to faster replication of E. cuniculi in these cells. Opsonisation of E. cuniculi spores with anti-E. cuniculi polyclonal antibody did not affect E. cuniculi replication in both, non-activated and activated murine macrophages. In contrast, opsonisation of E. cuniculi spores caused the most effective replication of E. cuniculi in activated PMJ2-R cells. However, production of nitric oxide by these cells was significantly more intensive than that in non-activated, infected cells, where the parasite replicated to a much lesser extent. Our results support the hypothesis that E. cuniculi uses phagocytosis for the infection of host cells. They also indicate that the mechanism by which spores of E. cuniculi are killed by macrophages is not dependent on nitric oxide and they reveal that PMJ2-R cells cannot substitute peritoneal murine macrophages in immunological studies on E. cuniculi.
The article is focused on the choice of interpolation types for toolpaths in NC programs. Interpolation type affects the interpretation of an NC program by the control system used in a CNC machine tool. It is important for a production engineer to know about the consequences of the use of various interpolation types in a specific CAM system for toolpath creation. For testing purposes, a general profile of a blade typically utilized in energy devices was used, with toolpaths for contour milling of its profile based on three interpolation types available in the CATIA CAM system (linear int., linear + circular int. and spline interpolation). The comparison of toolpaths is based on the number of blocks of the NC program, feed-rate profile measurement and measurement of machining time. For the machining and measurements, a real three-axis machine tool with the Sinumerik 840D control system has been used. and Obsahuje seznam literatury
With an increase in growth irradiance (from 15 to 100 % of full sunlight, I15 to I100), the maximum net photosynthetic rate (Pmax), compensation (CI) and saturation irradiances of A. annua increased. At full sunlight, A. annua had a high capacity of photosynthesis, while at low irradiance it maintained a relatively high Pmax with a low CI. The height and diameter growth, total and leaf biomass, and artemisinin content of A. annua decreased with the decrease in irradiance, which might be connected with lower photosynthesis at lower than at higher irradiance. Irradiances changed biomass allocations of A. annua. The leaf/total mass ratio of A. annua increased with decreasing irradiance, but the root/total mass ratio and root/above-ground mass generally increased with increasing irradiance. Thus A. annua can grow in both weak and full sunlight. However, high yield of biomass and artemisinin require cultivation in an open habitat with adequate sunshine. and M. L. Wang ... [et al.].
Photosynthetic and growth characteristics of Mosla chinensis and M. scabra were compared at three irradiances similar to shaded forest understory, forest edge, and open land. At 25 % full ambient irradiance, M. chinensis and M. scabra had similar photosynthetic characteristics, but saturation irradiance, compensation irradiance, and apparent quantum yield of M. chinensis were higher than those of M. scabra at full ambient irradiance and 70 % full ambient irradiance. At the same irradiance treatment, specific leaf area and leaf area ratio of M. chinensis were lower than those of M. scabra. Photon-saturated photosynthetic rate and water use efficiency of M. chinensis, however, were not significantly higher than those of M. scabra, and the leaf area and total biomass were lower than those of M. scabra. As a sun-acclimated plant, the not enough high photosynthetic capacity and lower biomass accumulation may cause that M. chinensis has weak capability to extend its population and hence be concomitant in the community. and J.-X. Liao ... [et al.].
The effect of sulphur deprivation and irradiance (180 and 750 µmol m-2 s-1) on plant growth and enzyme activities of carbon, nitrogen, and sulphur metabolism were studied in maize (Zea mays L. Pioneer cv. Latina) plants over a 15-d-period of growth. Increase in irradiance resulted in an enhancement of several enzyme activities and generally accelerated the development of S deficiency. ATP sulphurylase (ATPs; EC 2.7.7.4) and o-acetylserine sulphydrylase (OASs; EC 4.2.99.8) showed a particular and different pattern as both enzymes exhibited maximum activity after 10 d from the beginning of deprivation period. Hence in maize leaves the enzymes of C, N, and S metabolism were differently regulated during the leaf development by irradiance and sulphur starvation. and S. Astolfi, M. G. de Biasi, C. Passera.
Transthoracic echocardiography (TTE) has become an important modality for the assessment of cardiac structure and function in animal experiments. The acquisition of echocardiographic images in rats requires sedation/anesthesia to keep the rats immobile. Commonly used anesthetic regimens include intraperitoneal or inhalational application of various anesthetics. Several studies have compared the effects of anesthetic agents on echocardiographic parameters in rats; however, none of them examined the effects of different concentrations of inhalational anesthetics on echocardiographic parameters. Accordingly, the aim of this study was to examine the effects of different concentrations of isoflurane used for anesthesia during TTE examination in rats on basic echocardiographic parameters of left ventricular (LV) anatomy and systolic function. TTE examinations were performed in adult male Wistar rats (n=10) anesthetized with isoflurane at concentrations of 1.5-3 %. Standard echocardiograms were recorded for off-line analysis. An absence of changes in basic echocardiographic parameters of LV anatomy and systolic function was found under isoflurane anesthesia using concentrations between 1.5-2.5 %. An isoflurane concentration of 3 % caused a small, but statistically significant, increase in LV chamber dimensions without a concomitant change in heart rate or fractional shortening. For the purpose of TTE examination in the rat, our results suggest that isoflurane concentrations ≤ 2.5 % can be safely recommended., H. Říha ... [et al.]., and Obsahuje seznam literatury