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Biomedical subjects

G M Aleshina

Publications and source records attributed to G M Aleshina.

At least 19 recordsLinked to original sources
PubMed2006

alpha-Defensins from blood leukocytes of the monkey Papio hamadryas.

Three antimicrobial peptides named PHD1-3 (Papio hamadryas defensin) have been isolated from hamadryas baboon blood leukocytes using preparative electrophoresis and reverse-phase HPLC. The primary structures of these peptides have been determined by automated Edman degradation and mass-spectrometry. The results suggest that the peptides belong to the alpha-defensin family. Structural homology analysis reveals that among alpha-defensins from other animal species, PHD3 is the most closely related to RMAD5 (rhesus macaque alpha-defensin) (90% homology) from rhesus macaque leukocytes and also highly similar to human alpha-defensin HD5 (60% homology), which is produced by intestinal Paneth cells. The homology of PHD3 with human neutrophil alpha-defensin HNP1 (human natural peptide) was 30%. The primary structures of PHD1 and PHD2 are most similar to RED1 (rhesus enteral defensin), one of six enteral alpha-defensins of rhesus monkeys. PHD1-3 have been shown to be active against the Gram-positive bacteria Listeria monocytogenes and Staphylococcus aureus, the Gram-negative bacterium Escherichia coli, and the fungus Candida albicans, similarly to the human HNP1 defensin.

Amino Acid Sequence↗
PubMed2006

[Cardial fibrosis and the functional activity of leukocytes in patients with essential arterial hypertension].

The study revealed an increase in the serum levels of TGF-beta1 and the N-terminal peptide procollagen type III in patients with essential arterial hypertension (EAH), as well as an association between this increase and the duration of the disease, mean day arterial pressure profile, and left ventricular hypertrophy. An increased leukocyte functional activity is associated with disturbances in left ventricular diastolic function and an increase in TGF-beta1 serum concentration in EAH. The authors conclude that leukocytes participate in the development of myocardial hypertrophy and cardial fibrosis through the secretion of pro-inflammatory cytokines and peptide growth factors within the process of their activation.

Adult↗
PubMed2005

[Immunological parameters and mycobacterial biological properties in infiltrative pulmonary tuberculosis].

Thirty-one patients with infiltrative pulmonary tuberculosis were clinically and immunologically examined. A relationship was found between the definite immunological parameters and the biological properties of mycobacteria. The higher viability of mycobacteria and the increase in the drug resistance have been shown to be associated with the decreased activity of lymphocytes and the suppressed production of interleukin-2, which suggests a decrease in the activity of type 1 T helper cells and a significant increase in the synthesis of tuberculosis antibodies with the lower serum concentrations of circulating immune complexes. This is an informative indicator of a severe specific process, as previously established. Moreover, the authors show certain differences in the changes of immunological parameters in patients with infiltrative pulmonary tuberculosis with varying mycobacterial properties. Thus, the results of the performed study make investigators pay a particular attention to the immunopathogenetic value of the biological properties of Mycobacterium tuberculosis.

Adult↗
PubMed2003

[Parameters of acquired immunity and cation proteins of neutrophilic granulocytes in pulmonary tuberculosis].

Clinical and immunological studies of 61 patients with pulmonary tuberculosis have indicated that the status of acquired and congenital (natural) immunity assessed by the intra- and extracellular levels of cation proteins of neutrophilic granulocytes is different in different clinical forms of pulmonary tuberculosis. The found correlations suggest that there is a relationship between the factors of acquired and congenital immunity and that cytokines are involved in the regulation of specific inflammation. More active degranulation of azurophilic granules of neutrophils occurs due to myeloperoxidase. Unlike other forms, fibrocavernous pulmonary tuberculosis shows a negative correlation between intra- and extracellular content of cation proteins. The findings make it possible to use the parameters of congenital immunity for more detailed characterization of an immune response in tuberculosis, which may be essential in developing new pathogenetic therapy regimens.

Adult↗
PubMed2002

[Achievements and problems in studies of antibiotic peptides of an organic origin].

The paper contains the original data of the authors and literature survey in the field of studies of the structure and functions of antibiotic peptides. Physical-and-chemical as well as structural properties of a new subfamily of defensins, i.e. minidefensins (theta-defensins), are described in detail. Mechanisms of the antibiotic action of defensins and bactenecins as well as their role in regulating the body immune reactions are discussed.

Anti-Bacterial Agents↗
PubMed2000

[Cytotoxic and mitogenic effect of antimicrobial peptides from neutrophils on cultured cells].

Cytotoxic and mitogenic activities of human and rabbit defensines (HNP and NP-2, resp.) and pig antimicrobial peptides from leukocytes (PR-39, prophenin PF-2 and protegrin PG-2) were studied. The above peptides were added to serum-free cell culture medium of the target cell lines K562, L929 and Hep22a. Cytotoxicity was estimated within 1, 3, 6, 24 and 48 h of cell incubation with the tested peptides in concentrations 1, 10, 25 or 100 micrograms/ml. All the examined peptides exhibited a distinct time- and concentration-dependent cytotoxicity. Moreover, by contrast to pig peptides, defensines could induce proliferation in cell subpopulations from cell lines L929 amd Hep22a, or L929 (defensines HNP and NP-2, resp.), keeping resistance to their cytotoxic action.

Animals↗
PubMed1998

[An assessment of the immune status of the mucosal membranes in chronic rhinosinusitis].

The authors studied immune status of upper respiratory tracts mucosa in patients with different forms of chronic rhinosinusitis (purulent, polypous, vasomotor) in comparison to control subjects. An original complex of laboratory diagnostic techniques is proposed which can assess functional condition of the defense barriers of the upper respiratory tract mucosa in chronic inflammation, estimate impairment of specific and nonspecific resistance. This facilitates choice of optimal scheme of pathogenetic therapy of chronic inflammation in the upper respiratory tracts.

Antibody Formation↗
PubMed1995

Prophenin-1, an exceptionally proline-rich antimicrobial peptide from porcine leukocytes.

We purified and characterized an unusual antimicrobial peptide, prophenin-1 (PF-1), from porcine leukocytes. The peptide had a mass of 8,683 and contained 79 residues, including 42 (53.2%) prolines and 15 (19.0%) phenylalanines. Its N-terminal 60 residues consisted of three perfect and three nearly perfect repeats of a decamer, FPPPNFPGPR. Prophenin-1 was encoded on a cathelin-containing precursor and showed substantially more activity against E. coli, a Gram-negative bacterium, than against Listeria monocytogenes, a Gram-positive organism, in vitro.

Amino Acid Sequence↗
PubMed1995

[Thermodynamic parameters of complex formation of blood plasma fibronectin and myeloperoxidase].

Previous studies have demonstrated that fibronectin immobilized on BrCN-activated agarose forms a complex with soluble myeloperoxidase. The affinity of such interaction increases after preliminary absorption of fibronectin on a column with immobilized gelatin, one of its natural ligands. The thermodynamic characteristics of the myeloperoxidase interaction with fibronectin-gelatin-agarose have been established. The role of fibronectin-myeloperoxidase interaction in the inflammation focus is discussed in terms of the mode of the phagocyte loading with the enzyme and as a way of protecting intrinsic body tissues from injury by oxidants generated by extracellular myeloperoxidase.

Chromatography, Affinity↗
PubMed1994

Gallinacins: cysteine-rich antimicrobial peptides of chicken leukocytes.

We purified three homologous antimicrobial peptides ('gallinacins') from chicken leukocytes, examined their antimicrobial activity in vitro, and established their primary sequences by a combination of gas phase microsequencing and on-line LC-ESI-MS analysis of endo- and exoprotease peptide digests. The peptides contained 36-39 amino acid residues, were relatively cationic due to their numerous lysine and arginine residues, and each contained 3 intramolecular cystine disulfide bonds. Gallinacins showed primary sequence homology to the recently delineated beta-defensin family, heretofore found only in the respiratory epithelial cells and neutrophils of cattle, suggesting that beta-defensins originated at least 250 million years ago, before avian and mammalian lineages diverged. The 9 invariant residues (6 cysteines, 2 glycines and 1 proline) common to avian gallinacins and bovine beta-defensins are likely to constitute the essential primary structural motif of this ancient family of host-defense peptides.

Amino Acid Sequence↗
PubMed1994

[Hospital respiratory infections in children].

Acute respiratory superinfections (ARS) induced by secondary nosocomial respiratory pathogens and characterized by the subsequent generalization of the process have been reported as one of the main contributions to pediatric inpatient mortality. The recurrent infections were observed in all types of hospitals; they might be induced by the whole group of respiratory pathogens, but adeno-, coronaviral and pneumococcal ones are predominating. The ARS clinical picture showed various patterns determined both by the etiology of basic and recurrent infection and by a child's immunity. There was a correlation between the severity of ARS and the level of specific immunoglobulins, especially of secretory origin.

Acute Disease↗
PubMed1993

Protegrins: leukocyte antimicrobial peptides that combine features of corticostatic defensins and tachyplesins.

Porcine leukocytes contained three homologous peptides, PG-1, 2 and 3, that manifested potent microbicidal activity against Escherichia coli, Listeria monocytogenes and Candida albicans in vitro. The peptides ('protegrins') were composed of 16 (PG-2) or 18 amino acid residues, and, like tachyplesins (broad-spectrum antibiotic peptides of horseshoe crab hemocytes), they contained two intramolecular cystine disulfide bonds. Considerably smaller than defensins, protegrins nevertheless showed substantial homology to them, especially to the 'corticostatic' rabbit defensin, NP-3a. The relatively simple structure of protegrins should provide useful prototypes for constructing congeners with selectively enhanced host defense activities.

Amino Acid Sequence↗
PubMed1988

[Degree of structural homology of lactoferrins from milk and neutrophilic granulocytes].

Some physico-chemical properties of human and pig lactoferrins from milk and neutrophilic granulocytes were compared. It was shown that the lactoferrins from different cell and tissue sources of the same species (humans or pigs) are identical in terms of electrophoretic mobility, molecular weight, iron-binding capacity, absorbance spectra, amino acid and sugar compositions and peptide maps. Human and pig lactoferrins show a high degree of structural homology (approximately 50%), but are immunochemically different.

Amino Acids↗
PubMedDate not supplied

[Myeloperoxidase in the human placenta at preterm labor].

In the present study the level of myeloperoxidase in the human placenta at premature was investigated. Mycloperoxidase content did not depend on its localization in placenta and decreased at premature labour. It is suggested that the decrease in the myeloperoxidase content in placenta results in the weakening of antimicrobial barrier in the system mother-placenta-fetus and plays an important role in pathogenesis of premature delivery at later term.

Female↗
PubMedDate not supplied

[Cationic antimicrobial peptides as molecular immunity factors: multi-functionality].

Cationic antimicrobial peptides (AMP) of mammals (defensins, cathelicidins, protegrins and many others) are regarded as important components of congenital immunity. AMP are multifunctional molecules, capable of killing microorganisms directly by acting as endogenic, natural antibiotics ("immediate immunity"); in addition, they may take part in congenital and adaptive immune reactions (immunoregulation) and function as signal molecules, involved into tissue reparation, inflammation (including sepsis), blood coagulation and other important processes in the body. The molecular mechanisms of the direct antimicrobial action of AMP are considered. In addition to antimicrobial and immunoregulating action, AMP have influence on immunoneuroendocrine interactions, taking part in the pathogenesis of stress reactions (corticostatic action), as well as play the role of regulatory peptides of adaptogenic action. The many-sided character of the action of AMP opens prospects to the creation of new medicinal remedies on their basis. Such requirements are met by the Russian preparation "Superlymph" (a complex of natural cytokines), containing protegrin-like AMP.

Adaptation, Physiological↗