[Determination of the low protein concentration in biological fluids. Methodological aspects (the use of mathematical analysis)]. / Metodicheskie aspekty laboratornogo opredeleniia nizkikh konsentratsii belka v biologicheskikh zhidkostiakh (opyt primeneniia matematicheskogo analiza).

We investigated the effect of albumin/globulin ratio on the analytic error of protein determination. Several methods were used: Bradford, Lowry, pyrogallol-red, biuret, and sulfosalicylic acid. Reagents used in Lowry method exhibit higher affinity to globulins, whereas reagents used in other methods have higher affinity to albumins. Although the biuret method demonstrated equal efficiency in determining concentrations of various proteins low sensitivity of this method limits its clinical applicability. For other methods there was non-linear dependence of the analytic error on protein composition in the sample. Combination of two methods for protein determination (using one calibrator) completely removes the analytic error.

[Nonpathogenic Neisseria studied for the content of histidine decarboxylase]. / Issledovanie nepatogennykh neisserii na soderzhanie gistidindekarboksilazy.

Histidine decarboxylase activity was not found in cells of nonpathogenic neisseria, obtained from bronchi of patients with infectious asthma. The absence of the histidine decarboxylase activity in nonpathogenic neisseria cells suggests that the sensitizing activity of these cells was not caused by a direct effect of histamine of bacterial origin on human branchopulmonary tissues.

[Physico-chemical properties of deamidase AG from Pseudomonas fluorescens AG possessing antitumor activity]. / Fiziko-khimicheskie svoistva dezamidazy AG iz Pseudomonas fluorescens AG, obladaiushchei protivoopukholevoi sktivnost'iu.

Homogenous deamidase AG from Pseudomonas fluorescens AG was found to be a glycoprotein with molecular weight of about 13,000 daltons. The molecule consists apparently of four similar or identic subunits with molecular weight of about 30,000 daltons. The amino acid composition, N-terminal amino acids, the amount of chymotryptic peptides, containing 14C-carboxymethyl cysteine were studied. The enzyme exhibited distinct antitumoral effect on cells of Burkitt's lymphoma, sensitive to asparaginase, but did not exhibit marked cytotoxic action on cells of human ovarium cancer CaOV line, resistant to asparaginases.

[Purification of deamidase AG (asparaginase-glutaminase) from Pseudomonas fluorescens AG and some physicochemical properties of the enzyme]. / Ochistka dezamidazy AG (asparaginazy-gliutaminazy) iz Pseudomonas fluorescens AG i nekotorye fiziko-khimicheskie svoistva fermenta

Deamidase AG (asparaginase-glutaminase) was obtained from Pseudomonas fluorescens in a crystalline apparently homogenous state. Molecular weight of the enzyme, determined by acrylamide gel electrophoresis, was equal to 128 000 daltons; by ultracentrifugation (56100 rev/min, 65 min, 20.5 degrees C) coefficient of sedimentation was shown to be 7.36 S. Optimal pH for asparaginase activity of the enzyme was at pH 8.0-9.0, for glutaminase activity--at pH 5.5-7.5.

[Protein markers in evaluation of nephroprotective effects of antihypertensive drugs in patients with arterial hypertension]. / Belkovye markery otsenki nefroprotektivnogo deistviia gipotenzivnykh sredstv u bol'nykh s arterial'noi gipertoniei.

Fifty patients with stable slight and moderate uncomplicated essential hypertension, treated by ramipril, atenolol, or isradipine, were examined. Total protein and urinary excretion of individual proteins were studied before and after treatment. Urinary concentrations of apolipoproteins A1 and B1, alpha 1-acid glycoprotein, alpha 1-antitrypsin, prealbumin, albumin, beta 2-microglobulin, transferrin, haptoglobin, IgG and IgA, and C3 and C4 complement components were measured. Index of proteinuria selectiveness was calculated for each portion of urine. All three drugs exerted a nephroprotective effect, atenolol being the most active of them. Apolipoproteins, IgG, and complement components were the most valuable for diagnosis. Their excretion correlated with the severity of arterial hypertension and efficiency of treatment. Use of protein markers helps reliably assess the renal function and monitor the treatment efficiency.

[Protein markers of diabetic retinopathy]. / Belkovye markery diabeticheskoi retinopatii.

Total and 12 individual proteins were measured in the lacrimal fluid of children and adolescents with insulin-dependent diabetes mellitus. Lacrimal excretion of proteins helps diagnose the preclinical, nonproliferative, and preproliferative stages of diabetic retinopathy and predict the course of diabetic cataract.