The haemolytic action of different concentrations of HgCl2 on rat red blood cells (RBC ) was studied in vitro. The concentrations of HgCb in incubating media were 0.15, 0.25 and 0.50 mmol.l'1. The ionic strength of the media varied from 0 to 154 mmol.l1 NaCl, Isotonicity of solutions was also compensated using isotonic glucose in different concentrations (287-0 mmol.l"1). Osmolarity of solutions varied from 287 to 308 mOsm. Besides these solutions the haemolysis in Krebs-Ringer solution was also studied. Haemolysis was characterized with two maxima in all concentrations of Hg2+. The first maximum was observed at low ionic strength and the second one at high ionic strength. In relation to the increased concentrations of Hg2+, the first maximum of haemolysis progressively declined towards the higher ionic strength. In the Krebs-Ringer solutions, the increased concentration of Hg2+ was followed by reduced haemolysis. The haemolytic concentration of 0.15 mmol.l"1 was found to be optimal.
The content of phospholipids and their fatty acid composition were followed in the hearts of two inbred strains of rats: IR, resistant against the development of isoprenaline-induced myocardial lesions and IS, sensitive to their development. In the hearts of rats of the resistant strain, a lower content of phosphatidylcholine and its plasmalogen fraction was found compared to IS rats. The total amount of phospholipids was only insignificantly lower in IR rats. Greater differences were found in individual fatty acids. The most important finding concerned lower arachidonic acid and higher linoleic acid content in heart phospholipids of IR rats. These differences were exactly opposite to changes reported in the literature in animals known to have a higher resistance against myocardial damage due to various interventions. Our results do not support the hypothesis claiming the importance of changes in phospholipids and their FA composition for the resistance of the heart against the development of necrotic lesions.
The present study examined the hypothesis that the extension of noxious effect of methamphetamine (MA) on maternal behavior and postnatal development on the pups may differ in dependence with time of application. Female rats were injected with MA (5 mg/kg) or saline during first (embryonic day (ED) 1-11) or second (ED 12-22) half of gestation. Our results demonstrated that MA exposure on ED 12-22 led to decreased birth weight and weight gained during lactation period relative to rats treated on ED 1-11. Both sexes treated prenatally with MA on ED 1-11 opened eyes earlier compared to animals treated on ED 12-22. As a matter of sensorimotor development application of MA on ED 1-11 impaired the righting reflex, while MA exposure on ED 12-22 impaired the performance of beam balance test in male rats. There were no differences in maternal behavior. Therefore, it seems that MA exposure in the first half of the gestation impaired the early sensorimotor development that is under control of the brain stem, while the MA exposure in the second half of gestation affected the beam balance performance that is dependent on the function of the cerebellum., M. Malinová-Ševčíková, I. Hrebíčková, E. Macúchová, E. Nová, M. Pometlová, R. Šlamberová., and Obsahuje bibliografii
The degree of polyandry in a species is linked to other life history traits such as egg maturation, life span, and male ejaculate size and quality. The study of differences in mating strategies between closely related species can provide a better understanding of the evolution of these strategies and of sperm competition. Mating patterns of two closely related species of small ermine moths (Yponomeuta) were investigated in the laboratory. The average female age at first mating was higher in Y. cagnagellus than in Y. padellus. Both species mated more than once; however, Y. cagnagellus females were more likely to remate in a short time frame. Moreover, Y. cagnagellus had higher life time female mating frequencies than Y. padellus (viz., 3.0 versus 2.0). These differences in mating frequency were confirmed in the field by examining the presence of spermatophores (or their remains) in the bursa as well as sperm in the spermatheca of field-caught females.
Type I diabetes mellitus (DM1) is a complex disease with adverse effects on organs and tissues despite compensation by insulin treatment. The goal of our study was to study how kidney diseases change 31P MR parameters of muscle metabolism in DM1 patients with respect to gender. 51 DM1 patients (19 m/14 f without and 13 m/5 f with nephropathy) and 26 (14 m/12 f) healthy volunteers were examined using 31P magnetic resonance spectroscopy at 3T tomograph at rest, and during and after a calf muscle exercise. The exercise consisted of a six-minute plantar flexion using a pedal ergometer followed by a six-minute recovery. It is reflected by reduced relative β-ATP and increased Pi and phosphodiester signals to phosphocreatine (PCr) at rest and prolongation of the PCr recovery time after the exercise. Measurement on healthy volunteers indicated differences between males and females in pH at the rest and after the exercise only. These differences between patients groups were not significant. We have proven that nephropathy affects the metabolism in diabetic patients and our results confirm significant difference between patients with and without nephropathy. Gender differences in pH were observed only between male and female healthy volunteers., P. Sedivy, M. Dezortova, M. Drobny, Z. Vlasakova, V. Herynek, M. Hajek., and Obsahuje bibliografii
The saccadic eye movement-related potentials (SEMRPs) were recorded over various brain areas in a group of righthanders while they performed saccades to visual stimuli appearing either at regular or at irregular time intervals. The premotion positivity, motion execution component and lambda responses were of shorter latencies and lower amplitudes over the parietal areas as compared to the occipital ones. This finding did not depend on the regularity of intervals. With regular intervals, the positive wave starting before and peaking at the end of a saccade was found over the frontal eye fields. With irregular intervals, the premotion negativity was registered over the motor and frontal cortices. With saccades at regular intervals, the oculomotor components in the SEMRPs were less pronounced as compared to the irregular ones. These results are in accordance with the presumption that visual stimuli, appearing at irregular intervals, require higher attention and readiness to the oculomotor reaction, respectively, and also with the supposed role of the right hemisphere of righthanders in processing visual information.
Spontaneously hypertensive rats are the most common animal
model used to study attention deficit hyperactivity disorder
(ADHD). The present study investigated the levels of steroid
hormones in the bloodstream of hypertensive rats and its
normotensive control strain, Wistar-Kyoto rats, to check if there
are any hormonal differences between both strains at the onset
of ADHD. Plasma samples were collected from young (5-weekold) and mature (10-week-old) male hypertensive and
normotensive rats to determine the serum level of testosterone,
17β-estradiol, free estriol, progesterone, corticosterone and
cortisol using ELISA kits. The results showed statistically
significant increases in serum levels of testosterone and free
estriol in 10-week-old hypertensive and normotensive rats when
compared to 5-week-old animals. Moreover, the concentrations
of progesterone, corticosterone and cortisol were significantly
elevated in 10-week-old hypertensive rats when compared to
5-week-old animals of both strains as well as 10-week-old
normotensive rats. Hormonal differences observed between
10-week-old hypertensive and normotensive rats were also
accompanied by differences in the volumes of lateral ventricles as
well as the third ventricle and cerebral aqueduct. In conclusion,
elevated contents of progesterone, corticosterone and cortisol in
hypertensive rats may be associated not only with ADHD but also
with developing hypertension. This question needs further study.
Knowledge about the influence of latent toxoplasmosis on development and general biological condition of children is scant and thus the aim of the present study was to investigate these aspects in some detail. We compare school children in rural area seropositive and seronegative to the apicomplexan parasite Toxoplasma gondii (Nicolle et Manceaux, 1908) in terms of their developmental age, body mass and body height, physical fitness and end-of-term grades. Additionally, we evaluated the risk factors of infection with T. gondii such as the presence of cats in the household and eating raw meat products. With IFAT and ELISA tests, the prevalence of anti-Toxoplasma antibodies was 41% (190 children examined) and the rate of infection was higher in girls (44%) than in boys (36%). No significant differences were observed in morphological features and physical fitness of examined children. In girls the level of developmental age measured with electrophoretical mobility of nuclei method was significantly higher and school performance significantly lower for those infected with Toxoplasma than for uninfected; this finding was particularly intriguing. Only boys who ate raw meat products were more likely to be seropositive. The study provides some new information on gender differences in reaction to Toxoplasma infection.
The initially phytophagous caterpillars of Maculinea alcon and M. rebeli complete their development in Myrmica ant colonies as social parasites. Recent genetic studies show no differences at the species level among various populations of each butterfly taxa. Usually M. alcon and M. rebeli are identified by habitat and larval food plants (Gentianaceae) and host ant specificity is also considered to be an important feature. However most of the ecological characteristics overlap at least in some parts of their distributions. The developmental and survival characteristics of caterpillars reared by different Myrmica species were compared in laboratory experiments and in the field. Morphologically indistinguishable M. alcon and M. rebeli, which originated from Polish populations, are very similar in terms of host specificity i.e. larvae survived both with M. scabrinodis and M. sabuleti. However they showed different growth characteristics. The earlier flight period of M. rebeli, which is synchronized with the phenology of Gentiana cruciata, resulted from the quick growth of caterpillars in Myrmica nests in the pre-winter phase, when they gained about half of their final body biomass. After the end of winter they recommenced growth almost immediately. M. alcon larvae entered diapause shortly after adoption by ants and began to increase in weight significantly just one month after the onset of spring, which synchronized their development with that of their larval food plant, G. pneumonanthe. Therefore neither population group is transferable between habitats and should still be regarded, at least, as distinct conservational units.