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排序方式: 共有142条查询结果,搜索用时 15 毫秒
41.
A. V. Kirenskaya-Berus E. G. Lar'kina I. Yu. Kondrashin T. N. Lavrova V. V. Novototskii-Vlasov E. V. Makushkin 《Human physiology》2001,27(6):686-692
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. 相似文献
42.
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. 相似文献
43.
Parnova RG Bakhteeva VT Lavrova EA 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2001,87(12):1662-1672
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. 相似文献
44.
45.
The high‐fidelity replicative DNA polymerases, Pol ε and Pol δ, are generally thought to be poorly equipped to replicate damaged DNA. Direct and complete replication of a damaged template therefore typically requires the activity of low‐fidelity translesion synthesis (TLS) polymerases. Here we show that a yeast replisome, reconstituted with purified proteins, is inherently tolerant of the common oxidative lesion thymine glycol (Tg). Surprisingly, leading‐strand Tg was bypassed efficiently in the presence and absence of the TLS machinery. Our data reveal that following helicase–polymerase uncoupling a switch from Pol ε, the canonical leading‐strand replicase, to the lagging‐strand replicase Pol δ, facilitates rapid, efficient and error‐free lesion bypass at physiological nucleotide levels. This replicase switch mechanism also promotes bypass of the unrelated oxidative lesion, 8‐oxoguanine. We propose that replicase switching may promote continued leading‐strand synthesis whenever the replisome encounters leading‐strand damage that is bypassed more efficiently by Pol δ than by Pol ε. 相似文献
46.
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. 相似文献
47.
Parasites exert a selection pressure on their hosts and are accountable for driving diversity within gene families and immune
gene polymorphisms in a host population. The overwhelming response of regulatory T cells during infectious challenges directs
the host immune system to lose the ability to mount parasite specific T cell responses. The underlying idea of this study
is that regulatory single nucleotide polymorphism (SNPs) can cause significant changes in gene expression in functional immune
genes. We identified and investigated regulatory SNPs in the promoter region of the FOXP3 gene in a group of Gabonese individuals exposed to a variety of parasitic infections. We identified two novel and one promoter
variants in 40 individual subjects. We further validated these promoter variants for their allelic gene expression using transient
transfection assays. Two promoter variants, −794 (C/G) and the other variant −734/−540 (C/T) revealed a significant higher
expression of the reporter gene at basal level in comparison to the major allele. The identification of SNPs that modify function
in the promoter regions could provide a basis for studying parasite susceptibility in association studies. 相似文献
48.
Bachteeva V Fock E Lavrova E Nikolaeva S Gambaryan S Parnova R 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,293(1):R528-R537
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. 相似文献
49.
Cytokine-inducible SRC homology 2 domain protein (CISH) is a suppressor of cytokine signaling that controls interleukin-2
signaling pathway. We investigated the single nucleotide polymorphism (SNP) -292A>T in 473 Vietnamese hepatitis B virus (HBV)
carriers and 416 healthy controls. CISH variants at -292A>T were associated to HBV infection (Allelic: OR, 1.22 95% CI, 1–1.49; P = 0.04; Recessive: OR, 1.69 95% CI 1.23–2.54; P = 0.007). A gene dose effect for the risk allele -292T was observed (P = 0.04). The level of interleukin 2 and liver enzymes such as alanine transaminase, aspartate transaminase, total bilirubin,
and direct bilirubin were not associated to CISH polymorphism at position -292A>T This study associated the vital role of CISH SNP -292A>T variant to hepatitis B virus infection in a Vietnamese population. 相似文献
50.
A. P. Barannik N. V. Lavrova I. A. Shilov A. A. Koltunova L. A. Ozolinya L. I. Patrushev 《Russian Journal of Bioorganic Chemistry》2012,38(5):500-506
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. 相似文献