[Method of determining grisin residues in animal husbandry products]. / K metodike opredeleniia ostatochnykh kolichestv grizina v produktakh zhivotnovodstva.

The possibility of grisin binding in animal organs and tissues was studied and more accurate methods for determination of grisin in animal foods were developed. Such products as meat, milk, fat, eggs and subproducts (liver, kidneys, lungs), as well as organs and tissues of rabbits were tested. The antibiotic was added to the feed in an amount of 400 mg per head. The animals and poultry were killed 1 hour after the feeding. It was shown that grisin was partially bound in vitro and in vivo in the organs and tissues and could not be detected with the routine methods. A procedure for enzymatic hydrolysis of the homogenates with pancreatin, a proteolytic enzyme was elaborated by the authors for determination of the adsorbed or bound antibiotic. The procedure of the enzymatic hydrolysis used alone or in combination with thermal treatment provided determination of 90-100 per cent of grisin contained in the products, while the routine method of homogenization without thermal treatment revealed only 50-60 per cent (or 20-35 per cent in the liver). The use of the procedure increased the accuracy of the grisin traces determination 2.8-15.6 times as compared to the routine methods. It allowed one to obtain more correct data on the true levels of the drug in organs and tissues.

[Method of determining bacitracin residues in animal husbandry food products]. / K metodike opredeleniia ostatochnykh kolichestv batsitratsina v pishchevykh produktakh zhivotnovodstva.

Distribution of bacitracin in rabbits when given orally was studied. It was found that bacitracin was absorbed from the gastrointestinal tract, penetrated into the organs and tissues, was partially bound there and rapidly excreted with the urine and bile. The highest percentage of the antibiotic binding was registered in the bone marrow and organs of the lymphoid system. Since the binding of the antibiotic was selective (only in the organs of the lymphoid system) and its presence in the muscle tissue and subproducts (liver, kidneys, etc.) was in the trace amounts, they do not prevent the use of such products in food. Thermal treatment of such products eliminates the antibiotic activity which is also in favour of their use. Therefore, bacitracin may be widely used as a growth stimulator in cattle breeding. For detection of the bacitracin bound fraction in the organs, tissues and animal products it is recommended to use enzymatic hydrolysis of the biological substrates containing bacitracin with a 2 per cent pepsin solution prepared in phosphate buffer, pH 6.0-6.2.

[Characteristics of streptomycin distribution and binding in the body of rabbits depending on their immunobiological state]. / Osobennosti raspredeleniia is sviazyvaniia streptomitsina v organizme krolikov v zavisimosti ot ego immunobiologicheskogo sostoianiia

Some regularities of distribution and binding of streptomycin in the blood, organs and tissues of immunized rabbits werer studied. The leveles of the bound and free antibiotic in ther were determined. It was found that the immunobiological state of the rabbits had a definite effect on the distribution character and binding of streptomycin with proteins and cells in the animal organs and tissues. These changes were most pronounced in the organs and tissues of lymphoid and hematopoietic systems, the cells of which are indirect active participants of the immunity formation. As a result of proliferation of these cells the antibiotic was accumulated in higher amounts and bound more actively especially in the thymus gland and bone marrow, the central organs of the immunological reconstruction of the host. The studies are indicative of the presence of interaction between immunogenesis, distribution and binding of streptomycin in immunized animals.

[Distribution and binding of oxytetracycline in the body of immunized animals]. / Raspredelenie i sviazyvanie oksitetratsiklina v organizme immunizirovannykh zhivotnykh

Distribution and binding of oxytetracycline in immunized animals at various periods of immunogenesis (5, 10, 15, 20, 30 and 90 days after vaccination) were studied on rabbits, using dry live brucellosis vaccine, strain 19 as the antigen. The results of the study showed that immunological reconstruction of the macroorganism, its protective forces had a definite effect on the character of distribution, absorption and levels of oxytetracycline, as well as the processes of the antibiotic binding in the organism. The changes were indirect dependence on the immunogenesis periods: at the beginning of immunogenesis there was some increase in the antibiotic levels, as well as increased binding of the drug in the organs where reconstruction, activation and hyperplasia of the lymphoreticular cells occurred. During the productive phase of the antigen formation the antibiotic levels were 1,5-2 times lower, however, the processes of the antibiotic binding were more pronounced in the organs, where immunocompetent cells and antibodies were synthesized. During extinction of immunogenesis reduction of the initial antibiotic levels was recorded. Therefore, the changes directly depended on the periods of immunogenesis.

[Some patterns in the distribution of free and bound monomycin in the organs and tissues of immunized animals]. / Nekotorye zakonomernosti raspredeleniia svobodnogo i sviazannogo monomitsina v organakh i tkaniakh immunizirovannykh zhivotnykh

Distribution of unbound and bound monomycin in rabbits immunized against paratyphoid fever and colibacteriosis was studied at various stages of the immunization. The studies showed that the immunological reconstruction had a definite effect on the distribution character and the processes of the antibiotic binding in the vaccinized rabbits. The binding processes in the lymphoid cells increased, while those in the parenchimatose cells decreased. The concentration of the unbound and bound preparation in the organs and tissues at the background of the immunity was 2-3 times lower than that in the non-immunized animals. The bone marrow, where it markedly increased was an exception.