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Biomedical subjects

E V Ignat'eva

Publications and source records attributed to E V Ignat'eva.

At least 19 recordsLinked to original sources
PubMed2000

[Induction of apoptosis in murine myeloma cells NS0/1, transfected with the gene for the basic heat shock protein HSP70i].

Murine myelomas are rare cell variants deficient in inducible isoform of Hsp70 that protects cells from injury. In these cells Hsp70 is absent and is not induced under stress conditions. In this study myeloma cells NS0/1 were transfected with hsp70, and their susceptibility to apoptosis was challenged by serum deprivation or hydrogen peroxide. Expression of Hsp70 in NS0/1 cells made them more resistant to apoptosis in serum-free medium but did not affect their response to hydrogen peroxide. Hsp70 involvement in the protection of myeloma cells from apoptosis caused by different agents is discussed.

Animals↗
PubMed1991

The possible involvement of glucocorticoids in the development of genetically determined autoimmune pathology in NZB mice.

The total blood corticosterone concentration, the reactivity of the adrenal glands to exogenous adrenocorticotrophic hormone, and the binding capacity of corticosteroid-binding globulin (CBG), were determined in male NZB mice that spontaneously develop an autoimmune disease. The appearance of antibodies to endogenous erythrocytes was also monitored. This study was performed on animals of the following age groups: (1) 2-3-month-old animals prior to the appearance of autoantibodies; (2) 6-7-month-old animals in the period when the disease developed; and (3) 10-12-month-old animals, i.e. the period when the autoimmune disease developed. It was demonstrated that in the 10-12-month-old mice there was a sharp decrease in the total corticosterone level in the plasma (from 152 +/- 32 to about 20 micrograms l-1), and the reactivity of the adrenal glands to exogenous corticotrophin decreased (from 400% to 120%). However, the binding capacity of CBG increased with age which led to a decrease in the pool of active corticosterone in the blood. The increase in this capacity was especially pronounced in affected 10-12-month-old animals. (The number of binding sites increased from 0.64 +/- 0.05 to 0.8 +/- 0.03 microM and the values of the association constant for the binding of corticosterone to CBG increased from 0.29 +/- 0.05 to 0.91 +/- 0.07 microM-1). The combination of the above-mentioned changes suggests that there is a direct correlation between the decrease in the glucocorticoid background in the NZB mice and in the appearance of autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1990

[Effects of taktivin on corticosterone production by a suspension of mouse adrenal gland cells].

The influence of the thymic hormone, not imported preparation, taktivin, on the corticosterone production by the mouse (females, BALB/c) isolated adrenocortical cells was investigated. Taktivin (0.08 and 2 micrograms/ml) reliably decreased corticosterone production by the intact cells. After stimulation of the cells by the adrenocorticotropin, the suppressive effect of the thymic hormone was expressed more strongly. On the background of ACTH (1.6 microIU/ml) taktivin (0.00064-0.4 microgram/ml) decreased corticosterone production to a basal level. When the cells were stimulated by ACTH (1600 microIU/ml) taktivin (0.000125-2 micrograms/ml) decreased corticosterone production to a marked degree. These facts witness the important role of taktivin polypeptide components in realization of cooperation between the immune and endocrine systems.

Adjuvants, Immunologic↗
PubMed1988

[Effects of thymosin (fraction 5) on the endocrine function of the testis in mice].

The influence of the thymic hormone thymosin (fraction 5) on the hormonal function of testes form 2 months old BALB/c mice was investigated. It was shown that after 3 and 24 hours after thymosin administration there is a considerable decrease of plasma testosterone level as compared with the level of control animals, which were injected with BSA. 24 hours after administration of thymosin the in vitro production of testosterone by the testes was decreased essentially as compared with the control. Thymosin, injected together with indomethacin, inhibitor of prostaglandin synthesis, does not influence the hormonal activity of the testes. So, it was ascertained that thymic hormone thymosin participates in the regulation of the testes hormonal function. It is supposed that it's action on the gonads may be carried out through prostaglandins.

Animals↗
PubMedDate not supplied

[GeneExpress: an integrator for databases and computer systems accessible by the Internet and intended for studying eukaryotic gene expression].

We have developed GeneExpress that is the WWW-oriented integrator for the databases and systems supporting the investigation of gene expression. The total number of the Web-based resources integrated is 30. The database GeneNet on molecular events forming gene networks was assigned its integrative core. To navigate all these WWW-available resources, the SRS, HTML, and Java viewers were developed, http:@wwwmgs.bionet.nsc.ru/systems/GeneExpress/.

Database Management Systems↗
PubMedDate not supplied

[Gene networks].

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

[A generalized chemical-kinetic method for modeling gene networks].

Development of methods for mathematical simulation of biological systems and building specific simulations is an important trend of bioinformatics development. Here we describe the method of generalized chemokinetic simulation generating flexible and adequate simulations of various biological systems. Adequate simulations of complex nonlinear gene networks--control system of cholesterol by synthesis in the cell and erythrocyte differentiation and maturation--are given as the examples. The simulations were expressed in terms of unit processes--biochemical reactions. Optimal sets of parameters were determined and the systems were numerically simulated under various conditions. The simulations allow us to study possible functional conditions of these gene networks, calculate consequences of mutations, and define optimal strategies for their correction including therapeutic ones. Graphical user interface for these simulations is available at http://wwwmgs.bionet.nsc.ru/systems/MGL/GeneNet/.

Algorithms↗
PubMedDate not supplied

[Regulation of eukaryotic gene transcription: description in the TRRD database].

The structure of the Transcription Regulatory Regions Database (TRRD) and the principles of considering transcription regulation of eukaryotic genes in TRRD are concerned. Formal description of the structural and functional organization of the regulatory gene regions is illustrated with examples. By now, TRRD is based on 3500 original works and contains data on transcription regulation of more than 1100 genes known to possess more than 5000 transcription factor-binding sites and about 1600 regulatory elements (promoters, enhancers, silencers). TRRD is available at http://www.bionet.nsc.ru/trrd/.

Base Sequence↗
PubMedDate not supplied

[Comparative analysis of methods for recognizing potential transcription factor binding sites].

A complex approach to recognize transcription factor binding sites (TFBS) has been developed based on four methods: (i) weight matrix, (ii) information content, (iii) multidimensional alignment, and (iv) pairwise alignment with the most similar representative of known sites. It has been shown that no method optimal for all kinds of sites occurs among the considered methods, so in each case, the appropriate way of recognition should be chosen. The approach proposed allows one to minimize the errors of TFBS recognition. The program available through the Internet (http://www.sgi.sscc.ru/mgs/programs/multalig/) has been created to search for the potential TFBS in nucleotide sequences set by the user.

Base Sequence↗
PubMedDate not supplied

[Recognition of the potential SF-1 binding sites by SiteGA method, their experimental verification and search for new SF-1 target genes].

The SF-1 (Steroidogenic Factor-1) is a transcription factor known as a key regulator of the steroidogenic gene expression. SF-1 is required for the development and functioning at all levels of the hypothalamic-pituitary-gonadal and adrenal axis. Also it plays an essential role in sex determination. SF-1 is a member of the nuclear receptor superfamily and it activates gene expression by binding to DNA in a monomeric form. Here, we report the results of potential SF-1 binding sites identification by using the SiteGA recognition method. The SiteGA method was implemented using a genetic algorithm (GA) involving a iterative discriminant analyses of local dinucleotide context characteristics. These characteristics were compiled not only over the core binding sites region but over its flanks as well. Developed SiteGA method is characterized by considerably better recognition accuracy when compared to that for the weight matrix method. The experimental tests demonstrated that 83% of the sites recognized by the SiteGA method in the regulatory regions of steroidogenic genes, indeed, interact with the SF-1 factor. We also estimated the density of predicted sites in regulatory region of genes, the members of different functional groups and developed the criterion to search for new SF-1 target genes in genome sequences.

Algorithms↗
PubMedDate not supplied

[Method SiteGA for the recognition of transcription factor binding sites].

A new approach, SiteGA, for the prediction of functional transcription factor binding sites has been developed. The approach is based on the detection of locally positioned dinucleotides by the genetic algorithm and discriminant analysis. The approach has been applied to recognize transcription factor binding sites involved in the regulation of immune responses and cell growth (AP-1, IRF1, ISGF3, NFkappaB, STAT1), obesity and lipid metabolism (HNF4, PPAR, SREBP), and the expression of steroidogenesis genes (SF-1). SiteGA is far superior in accuracy to the traditionally used method of position weight matrices. The approach was implemented in the web tool, SiteGA http://wwwmgs2. bionet.nsc.ru/mgs/programs/sitega.

Algorithms↗
PubMedDate not supplied

[The effect of thymosin (fraction 5) and taktivin on adrenocortical function in mice].

A study was made of the effect of the thymic factors thymosin (fraction 5) and tactivin on adrenocortical function of BALB/C mature mice. A single administration of thymosin at a dose of 1 micrograms/mouse causes a rise of the blood level of corticosterone in 3 h. Dexamethasone, a blocker of ACTH secretion, stops the thymosin effect. Thymosin does not influence adrenocortical production of corticosterone in vitro. A marked tendency to a decrease in the blood level of corticosterone is clearly observed 3 h after tactivin administration at doses of 0.1, 0.5 and 2.5 micrograms/mouse. Tactivin added to the adrenal glands in vitro causes dose-dependent suppression of corticosterone specific production. A conclusion is that both factors act in opposite directions on adrenal functioning, and their influence on the glands is mediated differently.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Effect of thymosin (fraction 5) on the development of functional activity of the adrenals and gonads in genetically athymic mice].

The paper is concerned with the effect of thymosin, a hormone secreted by the thymus (fraction 5), on the development of adrenocortical and sex gland functions in genetically athymic mice (nude mutation). Multiple administration of thymosin to mice in the 1st month of their life (0.1 microgram/mouse twice a week) caused the suppression of corticosterone production by the adrenal glands in adult mice aged 2 mos., a considerable rise of the blood level of testosterone in male mice and the reduction of the specific production of estradiol by the ovaries in females. A thymosin-mediated role in the interaction between the immune and endocrine systems in the period of development of their functions was discussed.

Adrenal Glands↗