Use of regression analysis in the quantitative evaluation of the activity of biological preparations]

Use of regression analysis in the assessment of the activity of biological preparations under experimental conditions permitted not only to assess the quantitative effect (ED50) more strictly, but also to find other parameters of importance for the results of comparison, for example with the standard, i.e. in standardization. To these belong regression coefficient, parallelism of regressions, and the relative potency. By the presence of a parallelism one can judge the similarity between the activity mechanism of the active principle of the preparations being compared. Relative potency characterizes the activity of the preparation in the relative values in comparison with the standard, with a statistical evaluation of this value with the aid of the confidence interval. The authors suggest a program for Mir-2 computer facilitating the calculations in using the analystical method which is more objective than the graphic method of assessment of the linear dosage-response curve.     

On the auxin activity of glucobrassicin in biological tests

Bylo shledáno, ?e glukobrasicin p?sobí na dlou?ivý r?st úsek? koleoptile p?enice. Stimula?ní efekt glukobrasicinu m??e být sní?en p?ídavkem kinetinu. Auxinovou aktivitu glukobrasicinu nutno vzít v úvahu p?i vyhodnocování r?stových látek v rostlinách ?eledíBrassicaceae, Tovariaceae, Capparidaceae a Resedaceae.     

The effect of chemical preparations on the biological properties of the intestinal lactobacilli in experimental animals

The oral administration of the therapeutic doses of tetracycline, pefloxacin, ampicillin, cephalexin, rifampicin, sisomicin to Wistar rats for 5 days was accompanied by a decrease in the total number of lactobacilli in feces and by changes of the species spectre of these microorganisms. In those rats species, never found in intact animals, could be revealed rather frequently. All antimicrobial preparations administered in this investigation induced a decrease in the proportion of antibiotic-sensitive cultures and led to the selection of strains having multiresistance and increased antagonistic activity with respect to Pseudomonas indicator strain. The possible relationship between the markers antibiotic resistance and antagonistic activity in lactobacilli is discussed.     

Models of passive and active dendrite motoneuron pools and their differences in muscle force control

Motoneuron (MN) dendrites may be changed from a passive to an active state by increasing the levels of spinal cord neuromodulators, which activate persistent inward currents (PICs). These exert a powerful influence on MN behavior and modify the motor control both in normal and pathological conditions. Motoneuronal PICs are believed to induce nonlinear phenomena such as the genesis of extra torque and torque hysteresis in response to percutaneous electrical stimulation or tendon vibration in humans. An existing large-scale neuromuscular simulator was expanded to include MN models that have a capability to change their dynamic behaviors depending on the neuromodulation level. The simulation results indicated that the variability (standard deviation) of a maintained force depended on the level of neuromodulatory activity. A force with lower variability was obtained when the motoneuronal network was under a strong influence of PICs, suggesting a functional role in postural and precision tasks. In an additional set of simulations when PICs were active in the dendrites of the MN models, the results successfully reproduced experimental results reported from humans. Extra torque was evoked by the self-sustained discharge of spinal MNs, whereas differences in recruitment and de-recruitment levels of the MNs were the main reason behind torque and electromyogram (EMG) hysteresis. Finally, simulations were also used to study the influence of inhibitory inputs on a MN pool that was under the effect of PICs. The results showed that inhibition was of great importance in the production of a phasic force, requiring a reduced co-contraction of agonist and antagonist muscles. These results show the richness of functionally relevant behaviors that can arise from a MN pool under the action of PICs.     

Standardization of the method for estimation of ethambutol in pharmaceutical preparations and biological fluid

A simple column chromatographic method for determination of ethambutol (EMB) in pharmaceutical preparations containing EMB in combination with other anti-TB drugs is presented. The method involved extraction of EMB into an organic solvent, followed by basification and column chromatographic separation on Amberlite CG 50 (100-200 mesh) and elution with suitable eluants and estimation at a wavelength of 270 nm. The assay was linear from 25 to 400 microg/ml. The relative standard deviations of intra and inter day assays were lower than 5%. Ethambutol was recovered from human urine quantitatively and stable for a period of at least one week in urine stored at -20 degrees C.     

Use of paper discs in determining the biological activity of mycoheptin by the agar diffusion method]

Diffusion of mycoheptin from the discs into agar was studied. A procedure providing practical use of the discs for quantitative estimation of mycoheptin activity was developed. A possibility of using the discs in the assay of solutions containing significant amounts of an organic solvent was shown.     

Origin and diversification of the L-amino oxidase family in innate immune defenses of animals

L-amino acid oxidases (LAOs), because they produce hydrogen peroxide as a by-product, function in innate immune defenses of both vertebrates and mollusks. Phylogenetic analysis revealed two major subfamilies of LAOs: (1) a subfamily including LAOs from vertebrates and mainly from Terrabacteria and (2) a subfamily including LAOs from mollusks and Hydrobacteria. These subfamilies thus originated early in the history of life, implying that their innate immune functions in vertebrates and mollusks have evolved separately. Mammalian LAOs were found to belong to three separate clades: (1) LAO1, (2) LAO2, and (3) IL4I1. Phylogenetic analysis supported the hypothesis that LAO1 and LAO2 arose by a gene duplication prior to the divergence of marsupials from placental mammals, while IL4I1 duplicated from the ancestor of the LAO1 and LAO2 prior to the divergence of tetrapods from bony fishes. Mammalian IL4I1 clustered with LAOs from bony fishes, and these molecules shared a number of unique sequence features, including both amino acid replacements and a unique two-codon deletion. It is certain such unique features may be functionally important, especially three unique amino acid replacements in close proximity to the putative active site.     

Determination of sulpiride in pharmaceutical preparations and biological fluids using a Cr (III) enhanced chemiluminescence method

A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol–H₂O₂ system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol–H₂O₂–Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068–4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10^‐6 µg/mL and 2.83 × 10^‐5 µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd.     

Cellular test system for studying the biological properties of preparations with L-asparaginase activity

L-Asparaginase sensitivity and asparagin-deficiency of 5 tumor cell populations, i.e. mouse lymphoma L-1210, LI0-1, LTL, Berkitt lymphoma and human ovary cancer, line CaOv were studied. Radiometric estimation of 3H-thimidine incorporation into the cells of DNA served a criterion of cytotoxicity. "Krasnitin" (FDR) was used as L-asparaginase. The cells of leukemia L-1210, lymphosarcoma LIO-1 and line CaOv were asparagine-independent and non-sensitive to L-asparaginase. The cells of mouse lympholeukemia LTL and the cultures of Berkitt human lymphoma proved to be asparagin-dependent and highly sensitive to L-asparaginase. In concentration of 50 IU/ml the drug inhibited incorporation of 3H-thimidine in the cells of LTL and Berkitt lymphoma by 97-98 and 75-80 per cent respectively. Inhibition of 3H-thimidine incorporation in the cells of LTL and Berkitt lymphoma was more pronounced after incubation with the drug for 8 and 24 hours respectively. Two out of the 5 tumor cell populations were chosen as a result of the study. One of these 2 populations, i.e. the cells of Berkitt lymphoma was asparagin-dependent and highly sensitive to L-asparaginase, the other, i.e. the cells of line CaOv was asparagin-independent and resistant to the specific antitumor effect of the enzyme. The use of a system of these two cell lines provided estimation of the ratio of the specific cytostatic (antitumor activity) and non-specific cytostatic properties in the preparations with L-asparaginase activity.