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Biomedical subjects

M I Levi

Publications and source records attributed to M I Levi.

At least 19 recordsLinked to original sources
PubMed2003

[A simple biological method for the fast identification of antibiotics].

A method used to determine the quantitative and qualitative determination of antibiotics in blood, injury discharge, in human and animal urine as well as in foodstuffs (meat, milk and products made of them) is described. It is based on using obligate, thermophilic bacteria Bacillus stearothermophilus, strains KK BKM B-213OD and BKM B-718 with an optimum growth at 55-60 degrees C. Meso- and psychrophilic bacteria cannot grow at the above temperature, therefore, the studied non-sterile material does not need any preliminary thermal treatment prior to the indicator-strain, which is highly sensitive to all widely used antibiotics, is sown in the test-culture bacterial lawn.

Animals↗
PubMed2002

[A new method for total complement activity analysis and its clinical significance].

A test system consisting of a short-term suspension culture of mobile cells (bovine semen) is suggested for evaluating the complement activity. A simple and effective rapid method for evaluating the complement activity is based on the use of this system. Clinical application of this method helps evaluate the disease severity and predict the patient's condition in various diseases.

Complement Activation↗
PubMed1989

[Filament and cellulose acetate columns for affinity chromatography].

Single-use filament columns for affinity chromatography are described. Antigenic filaments for the isolation of pure antibodies have proved to be much more effective than antibody filaments for the isolation of antigens. Nitrocellulose filter has been employed for the preparation of paper columns that may be used for the isolation of pure antibodies 8-10 times.

Antibodies↗
PubMed1989

[Isolation of high-affinity antibodies from hyperimmune serum].

A group of high-affinity antibodies has been isolated from horse hyperimmune antiplague serum with the use of antigenic immunosorbent. High-affinity antibodies have proved to be homogeneous, which is indicated by the rectilinear character of the graph of the inverse values of the free antigen concentration.

Animals↗
PubMed1989

[The use of thermal analysis in developing chemical tests of sterilization].

A number of chemicals have been examined to find out whether they can be employed to test the temperature regimens of vapor and hot-air sterilization methods. Test kits for various temperature ranges and different sterilization modes have been selected. It is advisable that stains be used in tests (except the sulfur one) to control vapor (but not hot-air) sterilization.

Hot Temperature↗
PubMed1989

[Isolation of monoclonal antibodies for the identification of strains of the causative agent of plague that do not contain a capsular antigen].

In most cases the immunological identification of Y. pestis strains is based on the use of capsular antigen as an immunological marker. However, there are Y. pestis strains without capsular antigen. For the immunological identification of such strains, homogeneous antigen with a molecular weight of 43 KD has been isolated and monoclonal antibodies to it have been obtained. The enzyme-linked immunosorbent assay, carried out with the use of these monoclonal antibodies and intended for the detection of antigen with a molecular weight of 43 KD, has been developed. The sensitivity of the assay is about 10 ng/ml.

Animals↗
PubMed1989

[A new method of determining antibody heterogenicity (among them, monoclonal) by affinity].

In this assay, cellulose antigenic immunosorbent was used as solid phase and preparations of polyclonal and monoclonal bivalent antibodies as antibodies. The new method is based on the assumption that definite relationship exists between some of free molecules and some of bound active centers of antibodies in the process of the interaction of antibodies and antigenic immunosorbent. Groups of antibodies with different affinity were detected in hyperimmune horse serum, in immune mouse serum and in the monoclonal preparation, which, on the one hand, confirms our earlier data and, on the other hand, demonstrates the possibility of using the new method for determination of antibody affinity.

Animals↗
PubMed1989

[Theoretic scheme of immunoenzyme analysis (the "sandwich" variant)].

The sandwich variant of the enzyme-linked immunosorbent assay (ELISA) is a simple serological reaction of three components, and the antigen-antibody interaction follows the law of active masses. To increase the sensitivity of ELISA with respect to the antigen, the plates should be sensitized with moderate concentrations of antibodies and the confugate should be introduced at relatively low concentrations. To increase the activity of the conjugate, the plates should be sensitized with high concentrations of antibodies, but in this case the sensitivity of ELISA will not be high.

Antibodies↗
PubMed1988

[Antigenuria in plague-infected great gerbils].

In the urine of plague-infected great gerbils Yersinia pestis capsular antigen was detected by means of diagnostic preparations, both commercial and experimental (based on monoclonal antibodies). The antigen was detected in many urine samples taken from the animals over a prolonged period. The incidence and duration of antigenuria were found to be related to the survival time of great gerbils after infection and the level of antibodies in their blood. The number of animals with antigenuria markedly exceeded the number of animals from which Y. pestis was isolated, especially at a later period after infection. Examinations of urine samples from live great gerbils trapped in natural foci appears to be a method more effective in epizootiological survey than the bacteriological analysis of the animals.

Animals↗
PubMed1988

[Immunoenzyme analysis using paper disks].

Filter paper discs have been used in the enzyme immunoassay (EIA) as solid phase instead of polystyrene plates. The use of paper discs has made it possible to achieve a multiple increase in the sensitivity of sandwich EIA, thus permitting the detection of Yersinia pestis capsular antigen at a concentration of 0.4 ng/ml. Paper discs can be used not only for the sorption of antigen and antibodies, but also for the affinity purification of preparations.

Adsorption↗
PubMed1988

[Mechanism of the interaction of chloramine with Pseudomonas aeruginosa].

The disinfecting effect of chloramine on P. aeruginosa depends on the concentration of this disinfecting agent, the concentration of P. aeruginosa and the period of exposure, with consideration for the time of attaining equilibrium between the concentration of chloramine and P. aeruginosa, affinity between the disinfectant and bacterial cells, the number of chloramine-binding sites on a bacterial cell, the admixture of organic substances, pH and other environmental characteristics. The interaction of chloramine and P. aeruginosa can be subdivided into two stages: (1) the binding of the disinfectant by bacterial cells and (2) the death of the microbes. The mathematical description of the process of disinfection requires that the main characteristics be expressed in molecular parameters and the time factor be correlated with the terms of attaining the equilibrium for free and bound chloramine. The average number of binding sites for chloramine on a bacterial cell and the affinity constant of chloramine to binding sites have been estimated.

Chloramines↗
PubMed1987

[Field trial of an immunoenzyme method using beta-lactamase as the monoclonal antibody marker for the capsular antigen of the plague microbe].

Beta-lactamase (penicillinase) has been used as a marker of monoclonal antibodies in the enzyme immunoassay made with a view to the detection of Y. pestis capsular antigen and antibodies to it. The trial of the enzyme immunoassay with the use of the beta-lactamase conjugate in laboratories and under field conditions has revealed the advantage of this assay over hemagglutination tests commonly used for this purpose.

Animals↗