Neurophysiologial Study of the Hemispheric Organization of the EEG Spectrum in Mental Infantilism in Adolescents

Sixteen adolescents between 15 to 17 years of age with mental infantilism syndrome participated in the study. The data were compared with the control group including 10 mentally and neurologically healthy young subjects, secondary-school students in the 10th or 11th grades. The EEG was recorded monopolarly from 12 leads in the states of quiet wakefulness (closed eyes), on general activation (open eyes), when performing cognitive hemispheric-specialized tests, and when exposed to aversive sound stimulation. The studies showed that EEG spectral parameters could be regarded as the objective criteria of mental infantilism. In the baseline, the patients demonstrated the EEG characteristics typical of the earlier ontogenesis stage, i.e., a generalized increase in the spectral powers of -, ₁-, ₂-, and ₁-ranges and a decrease in the interhemispheric coherence in the frontal temporal region. When performing cognitive hemispheric-specialized tests, infantile patients were characterized by the insufficient differentiation of reactions to functional loads in terms of the frequency ranges, topography, and lateralization of changes, with the predominance of shifts in the ₂-range that is directly connected with nonspecific aspects of activation. On the presentation of sound stimulation, only the patients' group demonstrated an increase in the power of slow EEG ranges and interhemispheric coherence in the frontal temporal area. The results demonstrate the delayed formation of hemispheric specialization with a more retarded maturation of the nervous networks of the left hemisphere and the dysfunction of the frontal temporal regions of the brain.     

Comparison of imaginal diets of various Syrphidae (Diptera) species

The full amount and species composition of pollen from intestines of 11 species of Syrphidae (Arctophila fulva, Eristalis arbustorum, E. nemorum, E. pertinax, Helophilus pendulus, Myiatropa florea, Rhingia campestris, Sericomyia silentis, Syrphus baltheatus, S. ribessii and S. vitripennis), collected at the some place (Torma, Jogeva distr., Estonia) and at the some time (18-20 July 1989) have been studied. Maximum number of pollen grains is different fly species varied from 67,800 (Rh. campestris) up to 240,700 (S. silentis) grains, and average number from 25,560 (Rh. campestris) up to 115,880 (E. pertinax) grains. Maximum volume of pollen in different fly species varied from 1.5 (S. ribesii) up to 23.6 (S. baltheatus) mm3, and average volume from 0.36 up to 7.0 mm3 (the same species). The difference in a imaginal diets of Syrphidae are found, and the degree of difference does not correlate with a degree taxonomic affinity of species. The difference in strategy of a feeding behavior of two Syrphus species, that have similar diet, are marked: in intestines of 80% specimens of S. ribesii we found pollen grains of less that 7 plant species, whereas intestines of more than 88% specimens of S. vitripennis contained more than 8 species of grains. Distinction in alimentary preferences of different species of files can not be explained neither particularities of their morphology, nor their color preferences.     

Various effects of prostaglandin E2 on reabsorption of water and urea in the amphibia osmosis-regulating epithelium

Principal similarities between molecular pathways providing the enhancement of water and urea reabsorption under the action of argininvasotocin (AVT) in amphibian urinary bladder suggest that prostaglandin E2 (PGE2) could be a negative regulator of urea transport. To analyse this hypothesis, the role of PGE2 in regulation of urea transport was studied in isolated frog (Rana temporaria L.) urinary bladder. The urea permeability (Pu) was determined from the rate of efflux of (14) Curea from mucosal to serosal solution in isoosmotic conditions. The water permeability was measured in separate experiments in presence of an osmotic gradient. In contrast to water permeability, we were unable to demonstrate any inhibitory effect of 10-1000 nM PGE2 on AVT-stimulated urea transport using a variety of protocols. It was found that basolateral PGE2 exposure (10 nM-1 microM) caused an increase in Pu with no effect on osmotic water flow. The PGE2 effect was markedly inhibited by phloretin, a specific inhibitor of urea transporter. Sulprostone, an EP1/EP3 prostaglandin E2 receptor agonist, had no effect on Pu suggesting the contribution of EP2/EP4 receptor subtypes. In presence of osmotic water flow, the AVT-induced urea transport was significantly higher. This water flow-dependent urea permeability was inhibited by PGE2 although the inhibitory effect was less pronounced in comparison to the action of PGE2 on osmotic water flow. On the basis of these results we can make a conclusion that PGE2 has different role in regulation of water and urea transport in the frog urinary bladder. PGE2 could be considered as a stimulator of urea transport and an inhibitor of osmotic water flow activated by the AVT. The ability of PGE2 to regulate various types of cAMP-dependent transport by different mechanisms seems to be based on the presence of multiple basolateral PGE2 receptor subtypes in amphibian osmosis-regulatory epithelium.     

A morphological description of the brown shanny Stichaeus fuscus Miki et Maruyama, 1986 (Perciformes: Stichaeidae)

Findings of the brown shanny Stichaeus fuscus Miki et Maruyama, 1986 in waters of Russia are reported for the first time. The morphology of S. fuscus is studied in detail based on representative material; the taxonomic characters of this species are revised. A key to the species of the genus Stichaeus is given.     

Associations of Forest Type,Parasitism and Body Condition of Two European Passerines,Fringilla coelebs and Sylvia atricapilla

Human-induced forest modification can alter parasite-host interactions and might change the persistence of host populations. We captured individuals of two widespread European passerines (Fringilla coelebs and Sylvia atricapilla) in southwestern Germany to disentangle the associations of forest types and parasitism by haemosporidian parasites on the body condition of birds. We compared parasite prevalence and parasite intensity, fluctuating asymmetries, leukocyte numbers, and the heterophil to lymphocyte ratio (H/L-ratio) among individuals from beech, mixed-deciduous and spruce forest stands. Based on the biology of bird species, we expected to find fewer infected individuals in beech or mixed-deciduous than in spruce forest stands. We found the highest parasite prevalence and intensity in beech forests for F. coelebs. Although, we found the highest prevalence in spruce forests for S. atricapilla, the highest intensity was detected in beech forests, partially supporting our hypothesis. Other body condition or health status metrics, such as the heterophil to lymphocyte ratio (H/L-ratio), revealed only slight differences between bird populations inhabiting the three different forest types, with the highest values in spruce for F. coelebs and in mixed-deciduous forests for S. atricapilla. A comparison of parasitized versus non-parasitized individuals suggests that parasite infection increased the immune response of a bird, which was detectable as high H/L-ratio. Higher infections with blood parasites for S. atricapilla in spruce forest indicate that this forest type might be a less suitable habitat than beech and mixed-deciduous forests, whereas beech forests seem to be a suboptimal habitat regarding parasitism for F. coelebs.     

Prostaglandin E2 inhibits vasotocin-induced osmotic water permeability in the frog urinary bladder by EP1-receptor-mediated activation of NO/cGMP pathway

PGE(2) is a well-known inhibitor of the antidiuretic hormone-induced increase of osmotic water permeability (OWP) in different osmoregulatory epithelia; however, the mechanisms underlying this effect of PGE(2) are not completely understood. Here, we report that, in the frog Rana temporaria urinary bladder, EP(1)-receptor-mediated inhibition of arginine-vasotocin (AVT)-induced OWP by PGE(2) is attributed to increased generation of nitric oxide (NO) in epithelial cells. It was shown that the inhibitory effect of 17-phenyl-trinor-PGE(2) (17-ph-PGE(2)), an EP(1) agonist, on AVT-induced OWP was significantly reduced in the presence of 7-nitroindazole (7-NI), a neuronal NO synthase (nNOS) inhibitor. NO synthase (NOS) activity in both lysed and intact epithelial cells measured as a rate of conversion of l-[(3)H]arginine to l-[(3)H]citrulline was Ca(2+) dependent and inhibited by 7-NI. PGE(2) and 17-ph-PGE(2), but not M&B-28767 (EP(3) agonist) or butaprost (EP(2) agonist), stimulated NOS activity in epithelial cells. The above effect of PGE(2) was abolished in the presence of SC-19220, an EP(1) antagonist. 7-NI reduced the stimulatory effect of 17-ph-PGE(2) on NOS activity. 17-ph-PGE(2) increased intracellular Ca(2+) concentration and cGMP in epithelial cells. Western blot analysis revealed an nNOS expression in epithelial cells. These results show that the inhibitory effect of PGE(2) on AVT-induced OWP in the frog urinary bladder is based at least partly on EP(1)-receptor-mediated activation of the NO/cGMP pathway, suggesting a novel cross talk between AVT, PGE(2), and nNOS that may be important in the regulation of water transport.     

Unique polymorphism of the CYP21A2 gene encoding 21-hydroxylase in female patients with the signs of hyperandrogenism

Hyperandrogenism is a pathological condition characterized by a high level of male sex hormones (andogens) in a female organism. One of the main causes of hyperandrogenism is the autosomal recessive disease, congenital adrenal hyperplasia (CAH). More than 90% of all cases of this disease arise due to a mutation-induced decrease in the activity of the enzyme steroid-21-hydroxylase encoded by the CYP21A2 gene. In the present work, the sequencing of the full-size CYP21A2 gene from 16 female patients with well-pronounced signs of hyperandrogenism was performed; preliminarily the patients were tested for the presence in the CYP21A2 gene of nine most widespread mutations causing CAH (seven point mutations and 8-bp and ??30-kb deletions). The preliminary examination of the patients revealed no genotype that could lead to the development of the pathological phenotype. During the sequencing, 26 single nucleotide polymorphisms (SNP) were identified in the gene of which 25 were described in the literature (database dbSNP, NCBI). The gene of each patient had a unique combination of polymorphisms inherent only in this very woman. The novel SNP was localized in the 3??-terminal part of exon 8 and represented a synonymous C ?? T substitution. The SNPs were not uniformly distributed along the gene, but were arranged in clusters in the vicinity of the initiation and termination codons and near the boundaries of introns 2, 6, and 8. It was assumed that clinically neutral SNPs in unique combinations can, by themselves, affect either the spatial structure of CYP21A2 mRNA or the efficiency of pre-mRNA splicing and decrease the level of gene expression, which may lead to the development of the pathological phenotype in the patients.     

Increased secretion of lignolytic enzymes by the Lentinus tigrinus fungus after addition of butanol and toluene in submerged cultivation

We studied the effects of butanol and toluene on secretion of lignolytic enzymes by the Lentinus tigrinus fungus during submerged cultivation. Addition of butanol and toluene during the trophophase was followed by an increase in laccase and peroxidase activity of the culture and change in the composition of phospholipids and fatty acids. The ratio of phosphatidylcholine and phosphatidic acid decreased, while the amount of lysophosphatidylcholine, phosphatidylethanolamine, phosphoinositides, phosphatidylserine, and unsaturated fatty acids decreased. These changes resulted in an increase in the unsaturation index.     

Stochastic analysis of the GAL genetic switch in Saccharomyces cerevisiae: Modeling and experiments reveal hierarchy in glucose repression

Background

Most mathematical models of biochemical pathways consider either signalling events that take place within a single cell in isolation, or an 'average' cell which is considered to be representative of a cell population. Likewise, experimental measurements are often averaged over populations consisting of hundreds of thousands of cells. This approach ignores the fact that even within a genetically-homogeneous population, local conditions may influence cell signalling and result in phenotypic heterogeneity. We have developed a multi-scale computational model that accounts for emergent heterogeneity arising from the influences of intercellular signalling on individual cells within a population. Our approach was to develop an ODE model of juxtacrine EGFR-ligand activation of the MAPK intracellular pathway and to couple this to an agent-based representation of individual cells in an expanding epithelial cell culture population. This multi-scale, multi-paradigm approach has enabled us to simulate Extracellular signal-regulated kinase (Erk) activation in a population of cells and to examine the consequences of interpretation at a single cell or population-based level using virtual assays.

Results

A model consisting of a single pair of interacting agents predicted very different Erk activation (phosphorylation) profiles, depending on the formation rate and stability of intercellular contacts, with the slow formation of stable contacts resulting in low but sustained activation of Erk, and transient contacts resulting in a transient Erk signal. Extension of this model to a population consisting of hundreds to thousands of interacting virtual cells revealed that the activated Erk profile measured across the entire cell population was very different and may appear to contradict individual cell findings, reflecting heterogeneity in population density across the culture. This prediction was supported by immunolabelling of an epithelial cell population grown in vitro, which confirmed heterogeneity of Erk activation.

Conclusion

These results illustrate that mean experimental data obtained from analysing entire cell populations is an oversimplification, and should not be extrapolated to deduce the signal:response paradigm of individual cells. This multi-scale, multi-paradigm approach to biological simulation provides an important conceptual tool in addressing how information may be integrated over multiple scales to predict the behaviour of a biological system.