[Glucose isomerase activity in suspension of Arthrobacter nicotianae cells and adsorption immobilization of the microorganisms on inorganic carriers].

Kinetics of monosaccharide isomerization has been studied in suspensions of intact, non-growing Arthrobacter nicotianae cells. Under the conditions of the study, glucose and fructose were isomerized at the same maximum rate of 700 micromol/min per 1 g dried cells, which increased with temperature (the dependence was linear at 60-80 degrees C). The proposed means of adsorption immobilization of A. nicotianae cells involve inorganic carriers differing in macrostructure, chemical nature, and surface characteristics. Biocatalysts obtained by adsorbing the cells of A. nicotianae on carbon-containing foam ceramics in the coarse of submerged cultivation were relatively stable and retained original activity (catalysis of monosaccharide isomerization) throughout 14 h of use at 70 degrees C. Maximum glucose isomerase activity (2 micromol/min per 1 g) was observed with biocatalysts prepared by adsorption of non-growing A. nicotianae cells to the macroporous carbon-mineral carrier Sapropel and subsequent drying of the cell suspension together with the carrier.

[Catalytic properties of glucoamylase immobilized on the synthetic carbon material Sibunit].

Glucoamylase (commercial preparation Glucavamorin) was immobilized by sorption on a carbon support Sibunit. Starch saccharification by the resulting biocatalyst (dextrin hydrolysis) was studied. Investigation of the effect of adsorptional immobilization on kinetic parameters of glucoamylase, including the rate constant of thermal inactivation, showed that immobilization of Glucavamorin on Sibunit resulted in a thousandfold increase in glucoamylase stability in comparison with the dissolved enzyme. Presence of the substrate (dextrins) in the reaction mixture had a considerable stabilizing effect. Increase in dextrin concentration increases the thermostability of the immobilized enzyme. The overall factor of glucoamylase stabilization adsorbed on Sibunit with the presence of 53% dextrin solutions in comparison with the dissolved enzyme approximated 10(5). The biocatalyst for starch saccharification made on the base of Subunit-adsorbed Glucavamorin had a high operational stability. Its half-inactivation time at 60 degrees C exceeded 30 days.

[Effect of cyclosporin on tumor xenotransplantation under the renal capsule in mice]. / Effekt tsiklosporina na ksenotransplantatsiiu opukholei pod kapsulu pochki u myshei.

Stimulating effect of cyclosporine on growth and invasiveness of tumor xenographts was studied on a model of rat solid sarcoma M-1 transplanted under the kidney capsule in mice. Cyclosporine was administered subcutaneously in a dose of 25 or 75 mg/kg on days 1-7. The stimulating effect of cyclosporine was directly associated with the immunodepressant dose and accompanied by a decrease in the thymus weight. With using cyclosporine the model of xenographts under the kidney capsule can be of value in screening cytostatics and immunomodulators.

[Pharmacokinetic validation of the antitumor efficacy of aclarubicin administered by various routes in CBF1 mice with Ca 755 carcinoma]. / Farmakokineticheskoe obosnovanie protivoopukholevoiéffektivnosti aklarubitsina pri razlichnykh sposobakh primeneniia u myshei linii CBF1 s kartsinomoi Ca 775.

Aclarubicin was established to be more active against murine mammary gland carcinoma Ca 755 after its intravenous injection as compared to oral administration. Pharmacokinetics of aclarubicin and its biologically active metabolites MA 144 N1, MA 144 T1 and MA 144 M1 was studied by HPLC in the tumour tissues. Not only quantitative but also qualitative differences in the ratios of the unchanged antibiotic and its metabolites in tumour Ca 755 were detected after aclarubicin administration by these methods. Diverse therapeutic activity was shown to be due to these differences.

[Experimental antimetastatic activity of aclarubicin]. / Antimetastaticheskaia aktivnost' aklarubitsina v éksperimente.

Marked antimetastatic activity of aclarubicin, an anthracycline antibiotic, was demonstrated on models of spontaneous and artificial metastases of murine tumors such as Lewis lung carcinoma and melanoma B16. The activity depended on the antibiotic dose and administration regimen. The highest antitumor effect of aclarubicin was observed when the antibiotic was used at the earliest periods after intravenous injection of the tumor cells (the model of artificial metastases) or after amputation of the limb with the tumor (spontaneous metastases). Aclarubicin was active after administration by any of the routes used: intravenous, intraperitoneal and oral, the latter by its efficiency being not inferior to the parenteral administration. When used intravenously aclarubicin showed activity similar to that of adriamycin. However, after oral administration only aclarubicin had antimetastatic action.

[Pharmacokinetic study of aclarubicin. The distribution of the preparation and its biologically active metabolites in rat tissues]. / Farmakokineticheskoe izuchenie aklarubitsina. Raspredelenie preparata i ego biologicheski aktivnykh metabolitov v tkaniakh krys.

Tissue pharmacokinetics of aclarubicin and its active metabolites was studied with high performance liquid chromatography. The drug was administered to rats intravenously in single doses of 5 and 10 mg/kg and orally in a single dose of 10 mg/kg. With both the administration routes the highest concentrations of the drug and its metabolites were attained in the lymph nodes. Then followed the spleen and lungs. The lowest content of the drug was detected in the heart. The total values of the areas under the concentration/time curves for aclarubicin and its metabolites in the tissues of the heart, lungs, lymph nodes and spleen after oral administration were respectively 2, 3, 4 and 7 times lower than those after the drug intravenous administration in the same dose. The concentrations of the active metabolites MA144N1 and MA144T1 exceeded those of aclarubicin and were detected in the tissues within a longer period as compared to the unchanged drug. With repeated administration preferential accumulation of the metabolites in the tissues and their increased contribution to the aclarubicin antitumor effect could be suspected.

[Effect of the antibiotic variamycin on the growth of a rabbit brain tumor]. / Vliianie antibiotika variamitsina na rost opukholi golovnogo mozga krolika.

The effect of variamycin, an antibiotic of the group of aureolic acid on development of dedifferentiated astrocytoma of the brain was studied on rabbits. The antibiotic was administered intraperitoneally in a dose of 0.1 mg/kg daily for 6 days. The interval between the 6-day courses was 7 days. The results were estimated by changes in duration of the latent period of the tumor development in comparison to those in the controls. One course of the treatment with variamycin started late after the tumor transplantation, i. e. on the 18th day, resulted in an increase in the latent period duration by 25.7 per cent. Starting of the treatment with the antibiotic on the 6th day after the tumor transplantation resulted in an increase in the latent period duration by up to 69 or 74 per cent with the use of 2 or 3 treatment courses, respectively. The histological examination revealed pronounced dystrophic changes or complete resorption of the tumor tissue due to variamycin effect.

[Experimental study of the antitumor anthracycline antibiotic aclarubicin (aclacinomycin A)]. / Eksperimental'noe izuchenie protivoopukholevogo antratsiklinovogo antibiotika aklarubitsina (aklatsinomitsina A).

Aclarubicin (ACR) has a selective inhibitory effect on the synthesis of RNA in the cells. The time of the antibiotic contact with the cells is an important factor in realization of its cytotoxic activity. As compared to adriamycin, ACR has a low specific activity in lymphoid leukemia P388, melanoma B16 and lung cancer LL. The therapeutic efficacy of ACR depended on the scheme of its use: in treatment of rapidly proliferating tumors such as P388 the highest effect is attained with the daily use of the antibiotic for 9 days, in treatment of slowly developing melanoma B16 the results were more satisfactory with intermittent use of the drug on days 1, 5 and 9 after the strain transplantation. The new antibiotic was highly effective on its use either intravenously or orally.

[Pharmacokinetics of the new antitumor antibiotic reumycin in an experiment: the prediction of the human pharmacokinetic profiles]. / Farmakokinetika novogo protivoopukholevogo antibiotika reumitsina v éksperimente: prognozirovanie farmakokineticheskikh profilei u cheloveka.

The reumycin pharmacokinetics was studied with HPLC on Wistar rats after intravenous injection of the antibiotic in single doses of 2.5, 5 and 10 mg/kg and after its oral administration in single doses of 5 and 10 mg/kg. It was shown that the reumycin pharmacokinetics within the above dose ranges was nonlinear and within every dose could be described by a two-compartmental model. Its nonlinear nature might be associated with saturated binding of the antibiotic by the blood serum proteins. The absolute extent of the reumycin bioavailability after oral administration was 50 per cent. The variability of the reumycin cumulative renal excretion was due to bimodality of distribution of the parameter in the animals. Renal excretion of the intact antibiotic decreased from 35 to 20 per cent with increasing of the dose. The value of the reumycin half-life in humans was predicted (41-46 hours) with the pharmacokinetic animal scale-up.

[Action of aureolic acid and dactinomycin group antibiotics on human brain tumors in culture]. / Izuchenie deistviia antibiotikov gruppy aureolovoi kisloty i daktinomitsina na opukholi golovnogo mozga cheloveka v kul'ture.

The cytotoxic effect of antitumour antibiotics, such as dactinomycin, mithramycin, variamycin and olivomycin on the cells of the human brain tumours (multiform glyoblastoma, arachnoidendotelioma and astrocytoma) grown by the method of the primary plasmic culture was studied. Dactinomycin was superior to the antibiotics of the aureolic acid group in the rate and level of the cytotoxic effect on the tumour cells: 76 per cent of the above tumours were sensitive to dactinomycin, 56 per cent to mithramycin and 52 per cent to variamycin and olivomycin. Among the total number of the tumours sensitive to the drugs the number of the highly sensitive tumours amounted to 57.9 per cent for dactinomycin and 30.8--38.5 per cent for the antibiotics of the aureolic acid group. Definite differences in the efficiency of the antibiotics of the aureolic acid group with respect to different types of the brain tumours were observed.

[Antitumor activity of fatty acid derivatives isolated from protozoa]. / Protivoopukholevaia aktivnost' proizvodnykh zhirnykh kislot, vydelennykh iz prosteishikh.

Water-soluble monoethers of sucrose and fatty acids were obtained from Trypanosoma lewisi and Astasia longa. The maximum tolerated dose of the preparations on their single intraperitoneal administration was more than 25 g/kg. The doses of 10--40 mg/kg were used repeatedly in therapy. Carcinoma 755, Lewis carcinoma, sarcoma 45, sarcoma 37 and sarcoma 180 were sensitive to the preparations. The preparations were inactive against experimental leukemia.

[Results of determining the sensitivity of hypernephroid cancer to cytostatic agents in vitro and clinically]. / Rezul'taty opredeleniia chuvstvitel'nosti gipernefomoidnogo raka k tsitostaticheskim sredstvam in vitro i v klinike.

Sensitivity of the cells of 57 human hypernephromas was determined with respect to 8 drugs, i.e. tiodipin, fluorbenzotef, mithramycin, cyclophosphan, tiotef, rubomycin, 5-fluoruracyl and olivomycin with the help of the method of primary plasma cultures. Because of the changes introduced earlier into the estimative concentrations used in vitro, coincidence of the results of the sensitivity determined in vitro with the results obtained during the treatment of the same patients in clinics, significantly increased (up to 90 per cent).

[Results of a study of the pharmacokinetics of actinomycete RNAase in the bodies of white rats]. / Rezul'taty izucheniia farmakokinetiki aktinomitsetnoi RNK-azy v organizme belykh krys.

The pharmacokinetics of RNA-ase from Act. rimosus was studied on albino rats. The enzyme activity in the biological tests was determined spectrophotometrically by the increase of the acid-soluble products formed as a result of RNA-ase effect on RNA. The preparation was rapidly absorbed into the blood and organs, the maximum levels in the blood and organs being observed 30 minutes and 1 hour after the preparation administration. The preparation levels in the organs with the exception of the liver and kidneys were rather low. The highest levels observed in the kidneys and liver were 19.6 and 3.37 per cent respectively on the RNA-ase amount administered. Within the first 3 hours of the enzyme administration insignificant amounts of the substance were registered in the urine. Penetration of RNA-ase through the hemato-encephalic barrier was low.

[Results of an experimental study of the antitumor activity of 1-asparaginase from E. coli and Erw. carotovora]. / Rezul'taty éksperimental'nogo izucheniia protivoopukholevoi aktivnosti 1-asparaginazy iz E. coli i Erw. carotovora

The antitumour activity of the preparations of L-asparaginase from E. coli and Erw. carotovora with respect to lymphadenosis L-5178 and Yorker's carcinosarcoma (ascitic cariants) has been established. No difference in antitumour efficacy of the preparation of L-asparaginase obtained from E. coli and Erw. carotovora was noted.

[Role of the individual sensitivity to various cytostatic agents in children with neuroblastomas]. / O roli opredeleniia individual'noi chuvstvitel'nosti neiroblastom detei k razlichnym tsitostaticheskim sredstvam

Primary plasmic cultures of 33 tumors of the sympathic nervous system of children (27 neuroblastomas and 6 ganglioneuromas) were used for determination of their individual sensitivity to vincristin, vinblastin, dactinomycin, mithramycin, olivomycin, cyclophosphant bruneomycin and adriamycin. Most of the tumors were sensitive to vincristin, rubomycin an adriamycin. The data obtained in vitro and in the clinic were compared with respect to 12 cases (treatment with vincristin, combination of olivomycin with cyclophosphan, vincristin with rubomycin or cyclophosphan). Coinsidence of the results was observed in 8 cases. The method of primary plasmic cultures may be successfully used for determination of individual sensitivity of children with neuroblastomas to various cytostatics.

[C14-variamycin content in normal and tumorous brain tissues of white rats]. / Soderzhanie C14-variamitsina v normal'noi i opukholevoi tkaniakh golovnogo mozga belykh krys

Penetration of variamycin, a new antitumor antibiotic into the normal and tumor tissues of the brain of rats with multiform glioblastoma was investigated. The content of the C14-labeled antibiotic was determined radiometrically. The radioactive label penetrated into the normal and tumor tissues of the brain during the first hours after the drug administration. The level of the radioactivity in the tumor tissue was higher than that in the normal brain tissue during the whole period of the study. The greatest deviation in the contents of the radioactive label in the tumor and normal tissues was observed 2 and 3 hours after administration of the labeled antibiotic, i. e. 4.3 and 3.6 times respectively.

[Study of the distribution of C14-variamycin and C14-mitramycim after intravenous administration to mice]. / Izuchenie raspredeleniia C14-variamitsina i C14-mitramitsina posle vnutrivennogo vvedeniia mysham

Distribution of antitumor antibiotics, i.e. C14-variamycin and C14-mitramycin in the organs of albino mice after their intravenous administration in single doses was studied. Similarity in the distribution dynamics of both the antibiotics with respect to the animal organs was found. However, the level of variamycin as compared to that of mitramycin was much higher in the liver and especially the spleen. In the experiments with variamycin the radioactivity of the kidney tissue decreased more rapidly than in the experiments with mitramycin. Chromatographic analysis of the urine of the mice treated with C14-variamycin was performed. The labeled Variamycin was detected in the animal urine within 48 hours from the moment of the antibiotic administration. Its portion in the total amount of the radioactive products in the urine was 30 to 40% at various stages of the study.