An Approach to Better Estimation of the Initial Velocity of Enzyme Reactions.

A new algorithm for computation of the initial velocity of enzyme reaction at the time zero is proposed. This algorithm makes it possible to reduce the systematic error of measurements to the minimum, to estimate the reaction velocity in test samples regardless of the enzyme activity levels, and to minimize the assay time. The study is illustrated by an example of salivary alpha-amylase and standard reagent kit. The algorithm should not be applied if conjugated enzyme systems are used because there is a long initial lag phase in the kinetic curve.

EXTRACELLULAR VESICLES FROM BLOOD PLASMA STUDIED BY LOW VOLTAGE SCANNING ELECTRON MICROSCOPY.

Extracellular vesicles are subspherical membranous structures secreted by cells and enriched with different types of biological molecules. The number and the molecular content of these structures depend on pathological conditions and the physiological state of the organism. Extracellular vesicles play an important role in intercellular communication and represent potential disease biomarkers. However, mechanisms of formation, functions and morphological characteristics of extracellular vesicles are still studied insufficiently. Low voltage scanning electron microscopy is a promising method to investigate extracellular vesicles, since it does not require conductive coating and therefore enables a high-resolution visualization of morphological details of nanosized objects. This paper presents the results of low voltage scanning electron microscopy study of morphology and size of objects from blood plasma fractions.

[The optimization of technique of detection of cryoglobulins in conditions of clinical diagnostic laboratory].

The technique is proposed to evaluate cryoclobulins associated with IgM and IgG on the basis of detection of immune complexes circulating in healthy individuals and patients with liver cirrhosis. It is demonstrated that in patients with liver cirrhosis content of cryoclobulins associated with IgM increases almost twice and those associated with IgG more than two and a half times as compared with healthy individuals. It is established that in healthy individuals cryoclobulins are also present in blood in small amount. The proposed approach to detection of cryoclobulins permits to minimize time of implementation of study and also discharge of reagents.

[SPECTRAL AND ACID-BASE PROPERTIES OF HEMOLYMPH PLASMA AND ITS FRACTIONS FROM GASTROPOD PULMONATE MOLLUSC ACHATINA FULICA].

The set of normal biochemical indicators of the hemolymph plasma of gastropod pulmonate mollusc Achatinafulica is described. Comparative analysis of the whole plasma and its subfractions enriched and depleted of oxygen-carrying protein hemocyanin was performed by spectrophotometry and spectrofluorimetry methods. Individual features of the absorption spectra were analyzed using fourth derivatives. The optimum method for estimating protein concentration was chosen. To characterize acid-base properties of plasma hemolymph and its sub-fractions we calculated buffer capacity, equivalence points and pK values of dominant buffer groups. It is shown that the major role in maintaining the buffer capacity of hemolymph belongs to the bicarbonate system. These results are compared with data for Helix pomatia available in literature. In the future the indicators studied in this work will be used to develop ecotoxicological criteria for the environmental assessment.

[The study of partial tension of blood oxygen and forced expiration in patients with chronic obstructive bronchitis receiving inhalation of hypertonic salt solution]. / Issledovanie partsial'nogo napriazheniia kisloroda krovi i forsirovannogo vydokha bol'nykh khronicheskim obstruktivnym bronkhitom na fone ispol'zovaniia inhaliatsii gipertonicheskogo rastvora khlorida natriia.

To ascertain side effects of aerosol therapy which implies use of concentrated hypertensive salt solution (HSS), patients with chronic obstructive bronchitis (COB) and marked obstructive ventilation disturbances on HSS inhalation treatment were examined for PaO2 and bronchial patency. It was established that HSS inhalations do not affect PaO2 in COB patients. This expands opportunities for design of aerosol technology and its practical applications.

[beta-Glucosidase of leaves and roots of the common beet Beta vulgaris]. / beta-gliukozidazy list'ev i korneplodov stolovoi svekly Beta vulgaris.

beta-Glucosidases detected in the leaves and roots of common beet, Beta vulgaris, have been demonstrated to catalyze hydrolysis of native betacyanins. A method is described for the isolation and purification of beta-glucosidase from the roots, which involves ammonium sulfate precipitation, DEAE-cellulose chromatography, and Sephadex gel filtration. Maximum activity of the enzyme is detected at 50 degrees C and pH 8.0; it retains stability within the pH range from 5.1 to 9.2. In the leaves, beta-glucosidase is chloroplast membrane-associated; solubilization of the membranes results in the enzyme inactivation.

[Antibacterial drug resistance of gram-negative agents causing urinary infections in female outpatients in Russia: results of multicenter study]. / Rezistentnost' gramotritsatel'nykh vozbuditelei infektsii mochevyvodiashchikh putei k antibakterial'nym preparatam u ambulatornykh patsientok v Rossii. Rezul'taty mnogotsentrovogo issledovaniia.

AIM: To investigate the spectrum of gram-negative agents causing acute and recurrent cystitis in outpatients and sensitivity of uropathogenic E. coli to antibacterial drugs; to compare drug resistance of uropathogenic E. coli isolated in Russia and other countries. MATERIAL AND METHODS: The spectrum of gram-negative bacteria was identified in 299 cases of acute and recurrent cystitis in Moscow, Smolensk and Novosibirsk. 271 E. coli uropathogenic strains were examined according to CA-SFM and NCCLS criteria for sensitivity to ampicilline, gentamycin, trimetoprim, co-trimoxasol, nitrofurantoine, nalidixic acid, pipemidine acid, norfloxacine, ciprofloxacine, nitroxoline. RESULTS: E. coli, K. pneumoniae, K. oxytoca, P. mirabilis, P. vulgaris caused acute and recurrent cystitis in 90.6, 6.4, 1, 1.7, 0.3% of the examinees, respectively. For Moscow relative agents were: E. coli (80.8%), K. pneumoniae (13.1%), K. oxytoca (2.3%), P. mirabilis (3.1%), P. vulgaris (0.7%). In Smolensk E. coli, K. pneumoniae, P. mirabilis were isolated in 96.3, 2.5 and 1.2%, respectively. E. coli occurred in 100% of Novosibirsk cases. Mean Russian values of the resistance to ampicilline, gentamycin, trimetoprim, co-trimoxasol, nitrofurantoin, nalidixic acid, pipemidine acid, norfloxacine, ciprofloxacine, nitroxoline were the following: 33.3, 5.9, 20.3, 18.4, 2.9, 5.5, 4.4, 2.6, 2.6 and 94.1%, respectively. Resistance to 2 and more drugs was registered in 18.4% of E. coli strains. CONCLUSION: Cystitis in women was in most cases caused by E. coli. The highest resistance among uropathogenic strains E. coli was observed to nitroxoline, ampicilline, trimetoprim and co-trimoxasole; maximal antibacterial activity against uropathogenic E. coli was shown by fluoroquinolones (norfloxacin and ciprofloxacin).

[Relationship between the structure and antioxidant activity of various betalains]. / Vzaimosviaz' mezhdu stroeniem i antiokislitel'noi aktivnost'iu nekotorykh betalainov.

Antioxidant activities of nine betalains were studied on the model of linetol peroxidation. Betaxanthins were shown to have the highest antioxidant activity. The relationship between the chemical structure and antioxidant activity of betalains was examined.

[Embovin efficacy and tolerance in the treatment of patients with intestinal nematode infections]. / Effektivnost' i perenosimost' émbovina pri lechenii bol'nykh kishechnymi nematodozami.

The efficacy and tolerance of embovin, a new anthelminthic manufactured in Russia, was studied in 60 patients with nematodiases. The results evidence its high efficacy in ankylostomiasis (100%), enterobiasis (100%), and ascariasis (90 +/- 6.4%). The drug was well tolerated in all the cases. No adverse effects on the liver, pancreas, kidneys, as well as on the peripheral blood and urine composition were detected. This recommends embovin for wide use in medical practice.

[Changes in creatine kinase activity and protein spectrum of the developing muscle culture treated with creatine phosphate]. / Sdvigi kreatinkinaznoi aktivnosti i belkovogo spektra razvivaiushcheisia myshechnoi kul'tury, obrabotannoi kreatinfosfatom.

A study was made of the influence of creatine phosphate (CP) on creatine kinase activity and the total protein status of the primary chicken myoblast culture. It has been established that the two-hour exposure of the developing culture in the presence of 2 and 4 mM CP is accompanied by the lowering of the content of water extractable protein and a considerable increase of creatine kinase activity. Meanwhile the total activity of the enzyme rises in the non-differentiated and falls in the differentiated one. Electrophoretic analysis has shown CP to produce not only quantitative but also deep qualitative changes in the myoblast protein spectrum. It is assumed that the changes revealed are nonspecific.

[Comparative enzymologic analysis of the creatine kinases from the skeletal muscles of the cod, frog and rabbit]. / Sravnitel'no-énzimologicheskii analiz kreatinkinaz iz skeletnykh myshts treski, liagushki i krolika.

Electrophoretic studies have been made of the protein composition and isozymic pattern of the creatine kinase from muscles of the cod. It was shown that this enzyme constitutes up to 40% of total water-soluble proteins of muscle tissue. Isolation and purification procedures were suggested for the creatine kinase from cod muscles which allow to obtain the enzyme with the specific activity 250-350 IU/mg. Comparative enzymic analysis of creatine kinases from muscle tissue of the cod, lake frog, and rabbit was also made. Studies were carried out on temperature dependence of the reaction, kinetic constants at temperatures 5 and 30 degrees C were determined together with other physicochemical properties of the enzymes. The revealed species specific differences are discussed in relation to the structure and function of the enzymes in lower vertebrates in vivo.

[Biological activity of thymus preparations from sheep of various ages]. / Biologicheskaia aktivnost' preparatov timusa ovets raznogo vozratsa.

Thymus active fractions from 3-year-old sheep were shown to cause immune response stimulation to sheep red blood cells in experimental immune deficiency in mice. The fraction from fetal lamb and sheep thymus was more active than that of mature animals in increasing immune rosette-formation in the lymph of central and peripheral organs of the immune deficient mice. All the preparations recovered the number of splenocytes in immune deficient mice. Therefore, thymus active fractions obtained from sheep at different stages of ontogenesis had a stimulating effect on cell proliferation and immunogenesis.

[Method of calculating the specific growth rate of microorganisms by measurements of the substrate or product concentration]. / Metod vychisleniia udel'noi skorosti rosta mikroorganizmov po izmereniiam kontsentratsii substrata ili produkta.

A procedure and formulae are proposed for calculating the specific rate of microbial growth; these are based on measuring the concentration of either a limiting substrate or a product involved in the growth of a microorganism. Only the concentrations of a substrate (S) or a product (P) are determined periodically in the course of the cultural growth whereas the biomass yield (chi) in the medium is established only after long time intervals. The proposed equations may be used for controlling the specific growth rate in large-scale processes by the concentration of a product (or a substrate) using a computer, as well as in laboratory studies of mu as a function of the conditions for growth of slowly growing microorganisms.