Polymorphisms in glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genes in the indigenous and the nonresident population of the Kemerovo region

GSTM1 and GSTT1 gene polymorphisms were studied in Shorians, Teleuts, and Caucasians of the Kemerovo region. It has been shown that distribution of homozygous deletions in the examined groups is significantly heterogeneous. The frequency of deletion genotypes and combinations of deletion in these genes was lower in Shorians and, Teleuts than in Caucasians.     

Transcription of DNA-Methyltransferases in Endothelial Cells Exposed to Mitomycin C

Molecular Biology - DNA-methyltransferases catalyze DNA methylation in the CpG sites, which play an important role in the maintenance of genome stability. The association between DNA methylation...     

Telomeric DNA allocation in chromosomes of common shrew (Sorex araneus, eulipotyphla)

Recently, we displayed an Iberian shrew species (Sorex granarius) with telomere structures unusual for mammals. Long telomeres on the short acrocentric arms contain an average of 213 kb of telomere repeats, whereas the other chromosomal ends have only 3.8 kb (Zhdanova et al., 2005; 2007). However, it is not clear whether these telomeres are typical for all shrew species or only for S. granarius. S. granarius and common shrew Sorex araneus are sibling species. In this study, using modified Q-FISH we demonstrated that telomeres in S. araneus from various chromosomal races distinguished by their number of metacentrics contain 6.8–15.2 kb of telomeric tracts. The S. araneus telomere lengths appear to correspond to telomere lengths in the majority of both shrew species and wild mammals, whereas S. granarius has telomeres with unique or rare structures. Using DNA and RNA high-specific modified probes to telomeric repeats (PNA and LNA), we showed that interstitial telomeric sites in S. araneus chromosomes contain mainly telomeric DNA and that their localization coincide with some evolutionary breakpoints. Interstitial telomeric DNA in S. granarius chromosomes was not revealed. Thus, the distribution of telomeric DNA may be significantly different, even in closely related species whose chromosomes are composed of almost identical chromosomal arms.     

Interaction of FGF,Ihh/Pthlh,and BMP signaling integrates chondrocyte proliferation and hypertrophic differentiation

Mutations in fibroblast growth factor (FGF) receptor 3 lead to the human dwarfism syndrome achondroplasia. Using a limb culture system, we have analyzed the role of FGF signaling and its interaction with the Ihh/Pthlh and BMP pathways in regulating chondrocyte differentiation. In contrast to previous suggestions, we demonstrate that FGF signaling accelerates both the onset and the pace of hypertrophic differentiation. We furthermore found that FGF and BMP signaling act in an antagonistic relationship regulating chondrocyte proliferation, Ihh expression, and the process of hypertrophic differentiation. Importantly, BMP signaling rescues the reduced domains of proliferating and hypertrophic chondrocytes in a mouse model for achondroplasia. We propose a model in which the balance of BMP and FGF signaling adjusts the pace of the differentiation process to the proliferation rate.     

Structural and immunologic indicators of Peyer's patches in the human fetus

Histological and immunological methods were used for the investigation of the development of Peyer's patches in the ileum of 110 human fetuses of 8-29 weeks of gestation. The formation of Peyer's patches and the increased number of lymphatic follicles in them are described. Beginning from 8th-9th week of gestation T- and B-lymphocytes and their subpopulations (auto-RFC, EAC-RFC, IgM- and IgG-positive cells) can be identified in mononuclear cell suspension obtained from Peyer's patches. An increase in their number during embryogenesis and the pathways of lymphocyte migration are shown. By the moment of birth "O" cells dominant in Peyer's patches and later on E-RFC and IGM-positive cells prevail. Auto-RFC are the most scanty. The authors regard Peyer's patches as peripheral organs of immunogenesis involved in local defensive reactions and in the fetal immunogenesis system on the whole.     

BMP and Ihh/PTHrP signaling interact to coordinate chondrocyte proliferation and differentiation.

During endochondral ossification, two secreted signals, Indian hedgehog (Ihh) and parathyroid hormone-related protein (PTHrP), have been shown to form a negative feedback loop regulating the onset of hypertrophic differentiation of chondrocytes. Bone morphogenetic proteins (BMPs), another family of secreted factors regulating bone formation, have been implicated as potential interactors of the Ihh/PTHrP feedback loop. To analyze the relationship between the two signaling pathways, we used an organ culture system for limb explants of mouse and chick embryos. We manipulated chondrocyte differentiation by supplementing these cultures either with BMP2, PTHrP and Sonic hedgehog as activators or with Noggin and cyclopamine as inhibitors of the BMP and Ihh/PTHrP signaling systems. Overexpression of Ihh in the cartilage elements of transgenic mice results in an upregulation of PTHrP expression and a delayed onset of hypertrophic differentiation. Noggin treatment of limbs from these mice did not antagonize the effects of Ihh overexpression. Conversely, the promotion of chondrocyte maturation induced by cyclopamine, which blocks Ihh signaling, could not be rescued with BMP2. Thus BMP signaling does not act as a secondary signal of Ihh to induce PTHrP expression or to delay the onset of hypertrophic differentiation. Similar results were obtained using cultures of chick limbs. We further investigated the role of BMP signaling in regulating proliferation and hypertrophic differentiation of chondrocytes and identified three functions of BMP signaling in this process. First we found that maintaining a normal proliferation rate requires BMP and Ihh signaling acting in parallel. We further identified a role for BMP signaling in modulating the expression of IHH: Finally, the application of Noggin to mouse limb explants resulted in advanced differentiation of terminally hypertrophic cells, implicating BMP signaling in delaying the process of hypertrophic differentiation itself. This role of BMP signaling is independent of the Ihh/PTHrP pathway.     

A Triangulation Approach to Checking the Reliability of Estimation of Oscillatory Modes Embedded in an ECG Signal

Biophysics - Abstract—It is important to perform an analytical study of the oscillatory modes embedded in an ECG signal on individuals in certain occupations (power station operators, pilots,...     

Change in neuronal membrane permeability exposed to adenosine-3',5'-cyclophosphate]

Ionic current induced by intracellular injection of cAMP was divided into constituent parts, and the dependence of these components on membrane potential and ionic composition of extracellular medium was demonstrated. The computation shows that practically all background neurone permeability for potassium ions is cAMP-dependent.