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T P Egorova

Publications and source records attributed to T P Egorova.

At least 19 recordsLinked to original sources
PubMed1994

[Deep mycoses].

The problems of the diagnosis of deep mycoses such as candidiasis, aspergillosis and actinomycosis most frequent in this country are discussed. A classification system for deep mycoses based on the characteristics of the causative agents which is of practical value is presented. The microscopic and cultural diagnosticating of deep mycoses is described in detail. A brief information on the principles of the treatment of the mycoses is given.

Actinomycosis↗
PubMed1991

Protective ribosomal preparation from Shigella sonnei as a parenteral candidate vaccine.

A parenteral Shigella ribosomal vaccine (SRV) was investigated in animals for safety, antibody-inducing capacity, and protective activity. Ribosomal preparations from a Shigella sonnei phase I avirulent strain were obtained and shown to possess chemical, sedimentation, and other properties typical of bacterial ribosomes. No endotoxin contamination was revealed by a ketodeoxyoctonate assay, although the presence of some kind of O antigen was evidenced by serological findings and the high activity of SRV in inducing the O-antibody response and immunological memory in animals. SRV was nontoxic in mice, guinea pigs, and monkeys and induced no local reactions when injected subcutaneously in reasonable doses. Significant protection against a local Shigella infection (Sereny test) was seen in guinea pigs injected with SRV (efficiency index, about 60%) and the specificity of the protection was evident from cross-challenge experiments. The protective efficiency of SRV was especially high in rhesus monkeys challenged orally with virulent Shigella cells (89%, as calculated from the summarized data of several experiments in 71 animals). Protection in monkeys was long lasting and could be demonstrated several months after injection of SRV. An inexpensive technique can be used for the production of SRV on a large scale. The high immunogenicity of SRV is discussed in terms of the amplifying effect of the ribosome, which serves as a delivery system for polysaccharide O antigen. Further study of SRV as a candidate vaccine for humans seems justified by the data obtained.

Animals↗
PubMed1991

[The immunogenic and serological properties of the O-specific polysaccharide (L-hapten) in Shigella].

O-specific polysaccharide (L-hapten) was isolated earlier (Zh. mikrobiol. epidemiol. immunobiol., 1989, No. 11, pp. 8-11). In this paper L-hapten was shown to be unable, even at high concentrations (up to 2,000 micrograms/ml), to sensitize sheep red blood cells for passive hemagglutination by O-antibodies. At the same time classical LPS and heat-activated LPS were active at concentrations ot 32 and 8 micrograms/ml respectively. The O-antibody-neutralizing activity of L-hapten was lower than that of LPS 10(3)-10(4) times in the passive hemagglutination test and 25-50 times in competitive ELISA. The immunogenicity of isolated L-hapten was very weak: primary response in mice to the i.v. injection of 1-10 micrograms of L-hapten was similar to the effect produced by 10(-3)-10(-4) micrograms of LPS. No protective activity of L-hapten was noted in mice when the challenge dose of virulent shigellae was 16 LD50 or more, and only a weak protective effect was observed with a low challenge dose (8 LD50). The molecular basis of low serological and biological activity of L-hapten is discussed. The most probable explanation of the results obtained in this study is that L-hapten contains some nonspecific carbohydrates, inserted in or complexed with the O-side chain. Despite its low immunogenicity, L-hapten can be an important component of effective bacterial vaccines provided it is included into a suitable delivery system as is the case with Shigella ribosomal vaccine.

Animals↗
PubMed1991

[The immunogenic properties of the endotoxin protein: serum antibodies in animals and man].

Endotoxin protein or lipid A-associated protein (LAP) from Shigella sonnei was isolated and characterized earlier (Zh. mikrobiol. epidemiol. immunobiol., 1991, No. 4, pp. 47-50). In this investigation serum antibodies against LAP were studied in ELISA Anti-LAP antibodies were detected in high titers in the sera of nonimmunized mice, guinea pigs, rabbits, monkeys and healthy adults. We suppose that normal anti-LAP antibodies resulted from interaction between the immune system and environmental endotoxin. Parenteral injections of LAP to different animals induced intensive antibody response with a 100- to 1000-fold increase in the serum anti-LAP antibody level and a significant rise in the serum O-antibody level. The latter is seemingly due to the contamination of LAP with minute amounts of O-antigen (0.12% or less) and to the amplification of its immunogenicity by LAP. Both antigenic and amplifying activity of LAP was destroyed by proteinase K. The biological function of LAP and its possible use as a component of bacterial vaccines are briefly discussed.

Animals↗
PubMed1991

[Shigella endotoxin protein--its isolation and physicochemical characteristics].

The scheme of the isolation of endotoxic protein from S. sonnei 9090 is presented. The isolation procedure includes the 10-minute hot (at 68 degrees C) extraction of protein from endotoxin with 45% aqueous phenol, the precipitation of protein from phenolic extract with 9.5 volumes of 95% ethanol, the purification of protein from lipid material and pigments by multiple extraction with the mixture of chloroform and ethanol in the proportion 2:1 by volume. The yield of protein obtained with the use of this isolation scheme is about 3% of the initial endotoxin preparation. Protein preparations obtained in accordance with this scheme contain 92-95% of protein (determined by Lowry's method), 2.3-3.0% of saccharides (determined by the phenol-sulfate method) and 0.02% of hexose amine, its presence indicating that the preparations contain lipid A (or its fragments) which is firmly bound with endotoxic protein and cannot be extracted with chloroform. As shown in the passive hemagglutination inhibition test, the content of endotoxin in the preparations is less than 0.003%. Out of 7-11 bands revealed by electrophoresis in 15% polyacrylamide gel in the presence of sodium dodecyl sulfate, 3 main bands have molecular weights of 43, 38 and 18 KD. Three antigens differing in their electrophoretic mobility and diffusion rate in 1% agarose gel can be detected in the preparations by the method of immunoelectrophoresis with the use of antisera to both endotoxin and endotoxic protein.

Bacterial Proteins↗
PubMed1991

[Shigella endotoxin protein--its electrophoretic and serological properties].

The electrophoretic analysis of lipid A-associated protein (LAP), obtained from S. sonnei, in polyacrylamide gel in the presence of sodium dodecyl sulfate and urea has revealed the heterogeneity of the preparation; it has found to contain three main components with molecular weights of 43, 38 and 18 KD and some minor components with molecular weights of 49, 45 35, 30, 29, 27, 5, 21 and 14 KD. The electrophoretic mobility of the main protein components in the isolated preparation of LAP coincides with that of endotoxin components. The dissociation of proteins and lipopolysaccharide in the process of boiling the endotoxin in 2% sodium dodecyl sulfate is indicative of the noncovalent binding of these components. LAP contained in the endotoxin, in contrast to isolated LAP, is resistant to trypsin and proteinase K. The enzyme immunoassay (EIA) system with the use of LAP as a component of its solid phase has been developed, which makes it possible to carry out the quantitative determination of antibodies to this protein. The EIA system shows high sensitivity in the determination of anti-LAP IgG antibodies: in hyperimmune rabbit sera their titer is 1:250,000-1:800,000. As shown by the method of competitive EIA, the antigenic affinity of LAP of different origin corresponds to the degree of taxonomic propinquity of microorganisms: the maximal degree of cross reactions is observed between LAP obtained from S. sonnei, S. flexneri and Escherichia coli, while their affinity to Salmonella typhi is considerably less; remote microbial species (Bacterium bifidum and Sarcina marcescens) give practically no cross reactions.

Animals↗
PubMed1991

[The action of ribosomal preparations on nonspecific resistance to bacterial infection and on early tolerance to endotoxic shock].

Ribosomal preparations from Shigella flexneri and Shigella sonnei, introduced parenterally into mice, enhance their resistance to infection with the causative agents of typhoid fever and staphylococci. This effect is considerably less pronounced than that produced by the preparation of homologous lipopolysaccharide isolated by Boivin's method. After the administration of ribosomes nonspecific resistance to bacterial infective agents lasts for a short time. Ribosomal preparations do not enhance the resistance of mice to the lethal action of endotoxin.

Animals↗
PubMed1991

[The protective properties of the endotoxin protein].

The isolation and properties of endotoxin protein, or lipid A-associated protein (LAP), from Shigella sonnei were described earlier (Zh. mikrobiol. epidemiol. immunobiol., 1991, No. 4, pp. 11-17, and No. 7). In this report the data on its protective activity are presented. In experiments on mice one nanogram of LAP injected i. v. protected 50% of the animals against i. p. challenge with 40 LD50 of virulent S. sonnei. Guinea pigs injected s. c. with 10 micrograms of LAP were protected against local (keratoconjunctival) challenge with S. sonnei, the efficiency of immunization being 58%. LAP preparations containing no detectable amounts of O-antigen (less than 0.003%) were found to have a protective effect. Hyperimmune anti-LAP rabbit serum prevented local infection when incubated with S. sonnei challenge inoculum before injection into guinea pigs. Both active and passive protection induced by LAP was specific since no effect was observed in animals challenged with Shigella flexneri. In the homologous system the protective effect of anti-LAP serum was abolished by the addition of protein-free LPS. These results are compatible with the hypothesis that the protective activity of LAP depends on the presence of minute amounts of O-antigen whose immunogenic effect is greatly amplified by the protein component of the natural endotoxin complex.

Animals↗
PubMed1989

[O-specific L-hapten in the composition of Shigella sonnei].

Along with classical lipopolysaccharide (LPS), O-specific material not precipitated by ultracentrifugation has been isolated from the water-phenol extract of S. sonnei avirulent strain 9090 possessing complete antigenic properties. The purification of O-antigen contained in the supernatant fluid has been carried out by the gel filtration of the fluid, previously treated with ribonuclease, in a column packed with Sephadex G-100. The polysaccharide nature of O-antigen thus obtained, the absence of lipid A and KDO and the low content of hexoses, or core-specific saccharides of S. sonnei LPS, in this antigen make it possible to classify this material with O-components of microbial cells, described by different authors as "native protoplasmic polysaccharide" or "L-hapten" and formed by polymers of LPS O-side chains. The content of this component in S. sonnei strains under study is, on the average, 2.5% of the weight of dry microbial substance. L-hapten preparations obtained in the course of our investigations have been found to contain two O-specific antigens detected by immunoelectrophoresis and immunodiffusion, as well as by sedimentation in saccharose gradient, where they form peaks corresponding to 4.3 S and 10.8 S. This polysaccharide O-antigen is supposed to be capable of interaction with ribosomal particles and suitable for use as a component of ribosomal dysentery vaccines.

Antigens, Bacterial↗
PubMed1989

[The isolation and immunologic study of ribosomal preparations from Shigella flexneri].

S. flexneri ribosomal preparations were isolated by differential centrifugation or by fractionation with polyethylene glycol-6000. Their chemical composition and spectrophotometric properties were characteristic of ribosomes, and, as shown by the results of the serological assay, the content of O-specific component was, on the average, 1.4%. The ribosomal preparations were nontoxic for mice when injected intraperitoneally and intravenously in large doses and induced systemic O-antibody response in mice and rabbits. The parenteral administration of ribosomes to guinea pigs led to the increase of resistance to Shigella keratoconjunctivitis. The results of different tests with the use of this model greatly varied. According to the summary data of several tests, the ribosomal vaccine enhanced the resistance of the eyes from 11.3% to 48.5% and the effectiveness coefficient of immunization was 42 +/- 6. Ribosomes isolated from S. flexneri avirulent strain 2a 51.6 M (Iu. A. Belaia's vaccine) showed the same activity as those isolated from virulent strains. The results obtained in this study suggest the expediency of further experimental study of ribosomal preparations obtained from S. flexneri as potential vaccine.

Animals↗
PubMed1988

[Therapeutic effectiveness of ristomycin in the visceral form of actinomycosis (experimental research)].

Therapeutic efficacy of ristomycin in visceral actinomycosis, a severe disease difficult for diagnosis requiring long-term complex therapy was studied on 24 rabbits. The animals were divided into 4 groups. A model of thoracal actinomycosis was developed. 7 rabbits were treated with ristomycin. The other 7 rabbits were treated with ristomycin in combination with actinolysate, a specific immune preparation. 5 rabbits were treated with actinolysate alone and the other 5 rabbits received no treatment. alone and especially in combination with actinolysate was an efficient therapeutic agent for treatment of severe visceral actinomycosis. This allowed to recommend ristomycin for clinical trials in treatment of the disease.

Actinomycetales Infections↗
PubMed1988

[A protective factor of ribosomal shigellosis vaccine].

Shigella ribosomal vaccine was shown previously to possess protective properties in the keratoconjunctival test on guinea pigs and to be capable of preventing experimental infection in 90% of challenged monkeys. The presence of the O-specific component (OSC) constituting about 0.5% of the ribosomal preparation by serological activity suggested its importance for the protective effect. This was studied in experiments with two O-specific immunosorbents prepared by coupling anti-O rabbit antibodies with Staphylococcus aureus cells or with CNBr-Sepharose. Ribosomes treated with immunosorbents proved to be lacking the serologically active OSC and lost their ability to induce O-antibody response in rabbits and mice. After the removal of this component ribosomal preparations were incapable of ensuring protection from Shigella kerato-conjunctival infection. The isolated OSC was also inactive in this test. The data obtained in this investigation confirm the hypothesis stating that the protective activity of Shigella ribosomal vaccine is based on the combined action of ribosomes and O-specific factor whose nature and properties require further study.

Animals↗
PubMed1986

[Various properties and kinetics of interaction of high and low molecular weight human kininogens with human plasma kallikrein].

A relatively simple procedure for isolation and purification of human blood plasma kallikrein (HPK) by QAE-Sephadex A-50 SP-Sephadex C-50 and affinity chromatography on Sepharose 4B with immobilized soybean trypsin inhibitor with the activity yield of about 40% has been developed. The method allows for simultaneous isolation of low (LMW) and high molecular weight (HMW) kininogens from the same HPK sample. HPK preparations are homogeneous upon 7.5% polyacrylamide gel electrophoresis in the presence of 0.1% SDS; its Mr is 90,000. After treatment with beta-mercaptoethanol, HPK dissociates into two fragments with Mr of 43,000 and 37,000. HPK preparations have high specific activities of esterase (31 microM/min), amidase (78 microM/min), and kininogenase (420 micrograms equiv. bradikinin/min). The high degree of protein purification was demonstrated by titration of active centers with 4-methylumbelliferylguanidine benzoate. The values of equilibrium dissociation constants for the HPK complex with aprotinin (Ki) equal to 1 X 10(-8) M (ethyl ester of N-alpha-benzoyl-L-arginine) and 1,5 X 10(-9) M (HMW) were determined. The kinetics of HPK-induced liberation of bradikinin from purified preparations of HMW and LMW was studied. The kinetic parameters (Km, kcat and kcat/Km) of this reaction suggest a high affinity of HPK for HMW, but not for LMW. LMW does not compete with HMW for the enzyme active center. It is assumed that LMW is not a physiological substrate for HPK.

Bradykinin↗
PubMed1984

[Kininogenase activity of alpha and beta/gamma forms of bovine thrombin].

The kininogenase activity of alpha- and beta/gamma-forms of bovine thrombin with respect to the high molecular weight (HMW) and low molecular weight (LMW) human kininogens was studied. It was shown that both forms of the enzyme split of bradykinin from these kininogens. The kininogenase activity of alpha-thrombin is completely blocked by the highly specific thrombin inhibitor Nalpha-dansyl-L-arginine-p-ethylpiperidineamide, but not by the soya bean trypsin inhibitor. The alpha- and beta/gamma-forms of thrombin hydrolyze HMW (Km(app) = 4.5 and 3.3 microM, respectively) and LMW (Km(app) = 10.1 and 4.7 microM, respectively). The specific constants (kcat/Km(app) ) for thrombin with respect to the substrates differ about 7-fold, predominantly due to the high catalytic rates of HMW as compared to LMW; the kcat values are 0.18 and 0.06 min-1, respectively. alpha-Thrombin upon a long-term (over 1 hour) exposure to HMW, besides bradykinin, splits off the product inhibiting the kininogenase activity of thrombin. No differences in the specificity of the beta/gamma-form of thrombin with resect to HMW and LMW were detected.

Animals↗