RNA gel hybridization showed that the expression of monodehydroascorbate reductase (MDHAR) in the wild type (WT) tomato was decreased firstly and then increased under salt- and polyethylene glycol (PEG)-induced osmotic stress, and the maximum level was observed after treatment for 12 h. WT, sense transgenic and antisense transgenic tomato plants were used to analyze the antioxidative ability to cope with osmotic stresses. After salt stress, the fresh mass (FM) and height of sense transgenic lines were greater than those of antisense lines and WT plants. Under salt and PEG treatments, sense transgenic plants showed a lower level of hydrogen peroxide (H2O2) and malondialdehyde (MDA), a higher net photosynthetic rate (PN), and the maximal photochemical efficiency of PSII (Fv/Fm) compared with WT and antisense transgenic plants. Moreover, sense lines maintained higher ascorbate peroxidase (APX) activity than WT and antisense plants under salt- and PEG-induced osmotic stress. These results indicate that chloroplastic MDHAR plays an important role in alleviating photoinhibition of PSII by elevating ascorbate (AsA) level under salt- and PEG-induced osmotic stress., F. Li ... [et al.]., and Obsahuje bibliografii
BACKGROUND: Intussusception of the large bowel in adults is a very rare pathological condition. However, it has its clinical importance because intussusception is very often associated with an intraluminal lesion. CASE REPORT: We report two cases of the large bowel intussusception, ileocolic and colorectal. Both intussusceptions were associated with a malignant tumor. However, the clinical presentation was different. One of the intussusceptions was of non-transient character, while the second one resolved spontaneously before operation. Both patients underwent surgery and malignant tumors were found and removed. RESULTS: The purpose of the article is to draw attention to intussusception and emphasize that intussusception, either transient or non-transient, should be further examined. CONCLUSIONS: The intussusception may be the first and the only signal of the existence of a malignant tumor, very often colorectal carcinoma. and R. Vobořil, J. Fanta, P. Bačkovský, D. Ehrenberger, J. Vobořilová
The aim of the paper is to present transient calculations of an elastohydrodynamically lubricated (EHL) point contact. The paper focuses on the description of the numerical algorithm used to model non-smooth contacts with surface feature on one of the contacting bodies. Results of film thickness and pressure distributions of a selected surface feaure are presented. Simulations were performed and compared for two different rheology approaches (Newtonian, resp. non-Newtonian). and Obsahuje seznam literatury
Repeated postnatal caffeine treatment of rat pups led to transient developmental changes in cortical epileptic afterdischarges. To know if physiological cortical functions are also affected transcallosal evoked potentials were studied. Rat pups of the Wistar strain were injected daily with caffeine (10 or 20 mg/kg s.c.) from postnatal day (P) 7 to P11, control siblings received saline. Cortical interhemispheric responses were tested at P12, 18, 25 and in young adult rats. Amplitude of initial monosynaptic components was evaluated in averaged responses. Single pulses as well as paired and frequency (five pulses) stimulations were used. Developmental rules - highest amplitude of responses in 25-day-old rats, potentiation with paired and frequency stimulation present since P18 - were confirmed. Caffeine-treated rats exhibited transient changes: single responses were augmented in P25 if high stimulation intensity was used, paired-pulse and freque ncy responses were higher in experimental than in control anim als at P12, the opposite change was observed in 18- and more ma rkedly in 25-day-old rats. No significant changes were found in adult animals, monosynaptic transcallosal responses represent a simple and robust system. The developmental profile of described changes did not exactly correspond to changes in epileptic afterdischarges supporting the possibility that afterdischarges did not arise from early monosynaptic components of responses. In spite of transient nature of changes they can reflect delayed or more probably modified brain development., J. Tchekalarova, H. Kubová, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
The novel environment of a metabolic cage can be stressful for rodents, but few studies have attempted to quantify this stress-response. Therefore, we determined the effects on mean arterial pressure (MAP) and heart rate (HR), of placing mice of both sexes in metabolism cages for 2 days. After surgical implantation of a carotid artery catheter mice recovered individually in standard cages for 5 days. Mice then spent 2 days in metabolism cages. MAP and HR were monitored in the standard cage on Day 5 and in metabolism cages on Days 6-7. MAP increased by 18±3 and 22±4 %, while HR increased by 27±4 and 27±6 %, in males and females, respectively, during the first hours after cage switch. MAP decreased to baseline in the fourth and eighth h following metabolism cage switch in males and females, respectively. However, HR remained significantly elevated in both sexes during the entire two-day period in metabolism cages. Females had lower MAP than males both pre- and post- metabolism cage switch, but there were no sex differences in HR. These results demonstrate sustained changes in cardiovascular function when mice are housed in metabolism cages, which could potentially affect renal function., C. C. Hoppe ... [et al.]., and Obsahuje seznam literatury
To achieve a better understanding of learning and declarative memory under mild transient stress, we investigated the effect of brief hypobaric hypoxia on spatial orientation in rats. Young male Wistar rats aged 30 days were exposed for 60 min to hypobaric hypoxia, simulating an altitude of 7000 m (23 000 ft) either shortly prior to attempting or after mastering an allothetic navigation task in the Morris water maze with a submerged platform. The post-hypoxic group performed significantly better in the navigation task than the control animals (the mean difference in escape latencies was 11 seconds; P= 0.0033, two-way ANOVA with repeated measures, group × session). The experimental group also achieved a remarkably higher search efficiency (calculated as a percentage of su
ccessful trials per session), especially during the first four days following hypoxic stress (P= 0.0018). During the subsequent training, the post-hypoxic group performed better than the control animals, whilst the efficiency levels of both groups progressively converged. Spatial memory retention and recall of well-trained rats were not affected by the transient hyp
obaric hypoxia. These results indicate that brief hypobaric hypoxia enhances rats’ spatial orientation. Our findings are consistent with several studies, which also suggested that mild transient stress improves learning.
Cadmium is a heavy metal causing toxicity especially in kidney
cells. The toxicity is linked also with enhanced oxidative stress
leading to cell death. On the other hand, our recent experiments
have shown that an increase of total intracellular dehydrogenases
activity can also occur in kidney cells before declining until cell
death. The aim of the present study, therefore, was to evaluate
this transient enhancement in cell viability after cadmium
treatment. The human kidney HK-2 cell line was treated with
CdCl2 at concentrations 0-200 µM for 2-24 h and intracellular
dehydrogenase activity was tested. In addition, we measured
reactive oxygen species (ROS) production, glutathione levels,
mitochondrial membrane potential, and C-Jun-N-terminal kinase
(JNK) activation. We found that significantly increased
dehydrogenase activity could occur in cells treated with 25, 100,
and 200 µM CdCl2. Moreover, the results showed an increase in
ROS production linked with JNK activation following the
enhancement of dehydrogenase activity. Other tests detected
no relationship with the increased in intracellular dehydrogenase
activity. Hence, the transient increase in dehydrogenase activity
in HK-2 cells preceded the enhancement of ROS production and
our finding provides new evidence in cadmium kidney toxicity.
Protein kinase C (PKC) appears to play a significant role in the signal transduction of cardiac growth and development. The aim of this study was to determine changes in the total PKC activity and the expression of PKC isoforms α, δ and ε in the rat heart that was affected by pressure overload imposed at postnatal day (d) 2. Three groups of Wistar rats were employed for the experiment: rats submitted to the abdominal aortic constriction (AC), sham-operated controls (SO) and intact controls. Animals were sacrificed at d2, d3, d5 and d10. The total PKC activity was measured by the incorporation of 32P into histone IIIS and the expression of PKC was analyzed by immunoblotting in the homogenate of the left ventricular myocardium and in the cytosolic, membrane-enriched (105 × g) and nuclear-cytoskeletalmyofilament- enriched (103 × g) fractions. We observed the significant transient increase in both the total PKC activity and the expression of all isoforms at d5 (the 3rd day after the operation) in the cardiac homogenate of AC rats as compared with SO animals. Aortic constriction did not significantly affect the distribution of activity and isoform abundance among individual cellular fractions except for PKCδ, which increased significantly at d10 in the cytosolic fraction at the expense of the membraneenriched fraction. It is concluded that PKCα, PKCδ and PKCε undergo transient upregulation associated with the accelerated cardiac growth induced by pressure overload imposed in the very early postnatal period., B. Hamplová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
This paper presents a new technique for fingerprint image matching in biometric security applications, based on the hybrid of Neural Network and Delaunay Triangulation methodology. The Delaunay triangulation of the minutiae set is transformed to a set of points in the discretized space using duality. This translation results in a sampling method be acquiring which the system tolerates displacement and noise of the input image. Finally, Transiently Chaotic Associative Network (TCAN) is used to learn the obtained pattern. Experimental results show a significant improvement in the False Rejection Rate over both the traditional Delaunay Triangulation based approach and direct Neural Network application.