Biomedical subjects
Publications and source records attributed to W Steuden.
Use of lysostaphin to remove non-phagocytized, granulocyte-adherent bacteria allows more precise calculation of the percentage of the ingested as well as killed bacteria in the process of phagocytosis.
The effect of tuftsin, its synthetic analogs and arginine on phagocytosis of Staphylococcus aureus by granulocytes from leukemic children was investigated in vitro. The high stimulatory effect of tuftsin and arginine was shown. The decrease of phagocytosis of PMN from healthy subjects after preincubation with its analogs and arginine was observed, suggesting the regulatory effect of these peptides.
For determination of phagocytosis of Staphylococcus aureus 519 labeled with glycine-1-14C by guinea pig granulocytes, the third analytical program of LS 7500 counter was used. By measuring isotope radioactivity, the program enables evaluation of the percentage of a bound isotope in relation to the reference sample. In the present experiments the percentage of a bound isotope stands for the percentage of phagocytized bacteria calculated in relation to a reference sample, i.e. to radioactivity of bacteria added to the test. The program applied allows an automatic calculation of the percentage of phagocytized bacteria, the result being printed by a counter printer.
The use of a specific bacteriophage to remove non-phagocytized bacteria from the surface of phagocytic cell membrane made possible more precise determination of a number of phagocytized organisms.
Radioisotopic methods for determination of the biological activity of tuftsin was applied to study the stimulatory effect of this compound as well as of its components. This effect appeared to be dependent on the presence of two amino acids - Proline and Arginine. Administered jointly, they exert much stronger effect than separately.
The results presented in this paper revealed high or moderate activity of ten out of nineteen amino acids tested. Strong activity stimulating phagocytosis was noted in the presence of leucine, isoleucine, proline, arginine and histidine; moderate in the presence of serine, cysteine, hydroxyproline, aspartic acid and glutamic acid. Alanine, glycine, valine, threonine, phenylalanine, tyrosine, tryptophan, methionine and lysine did not stimulate phagocytic activity of PMN.
New screening system for the evaluation of preparations with potential cytostatic and immunotropic activity has been suggested. It consists in their interaction in relation to the mitogenic activity of phytohemagglutinin. A group of preparations, derivatives of 4,5-dihydro-2H-pyridazinone-3 was evaluated. It appeared that among the examined compounds there were preparations suppressing or stimulating the incorporation of 14C-thymidine to lymphocyte nuclei. Dependence between chemical structure and pharmacological activity in this group of compounds is discussed.
New screening system was used for the evaluation of preparations wih potential anti-mitotic, cytostatic and secondarily, immunodepressive activity. A group of compounds, derivatives of propionic and hydroxybutyric acids and of tetrahydrofuranone-2 was analyzed. It was showed that among them there were preparations reducing 14C-thymidine incorporation to lymphocyte nuclei. The authors pointed to the fact that in this mechanism, beside specific component, nonspecific component takes part, which results from the change of pH of the medium by the solutions of the investigated preparations. Relation between chemical structure and pharmacological activity in this group of compounds is discussed.
Activity of a group of hexahydrochromate derivatives was evaluated as compared to the mitogenic activity of phytohemagglutinin. The tested compounds displayed only slight activity although chromate derivatives are known for their antiinflammatory and anti-allergic effect. It was known that affinity to nucleic acids is indispensable for the induction of cytostatic effect of the preparations and not necessary while inducing antiinflammatory and antiallergic effect.
An isotopic method for determination of phagocytic activity is presented. The method of labeling of Staphylococcus aureus 519 with 14C is described. Effects of various parameters (e.g. time of incubation, serum dilution, number of phagocytes and bacteria used in the test on phagocytosis were studied. The effect of tuftsin and its lysine analogue on phagocytes is also described.
The speed of eliminating allogenic erythrocytes labeled with 51Cr from circulation was examined. Donor's erythrocytes with AFHR phenotype were injected to the recipient with FR phenotype. A fast elimination of allogenic erythrocytes was observed, T 1/2 = 7.6 days. The survival time of autogenic erythrocytes was T 1/2 = 18.2 days. In sera of those rabbits to whom allogenic erythrocytes had been injected, no anti-erythrocyte antibodies against the donor's hemocytes appeared.
An isotopic method for determination of phagocytic activity is presented. The method of labelling of Staphylococcus aureus 519 with 14C is described. Effects of various parameters (e.g. time of incubation, serum dilution, number of phagocytes and bacteria undergoing phagocytosis) on phagocytosis were studied. The effect of tuftsin and its lysine analogue on phagocytic granulocytes is also described.
The influence of pharmacologic stimulation and blocking of the beta-adrenergic system on appearance of PF and RF cells, and intralymphocytic levels of cAMP were investigated. Stimulation of the beta-adrenergic receptor exerted an immunosuppressive effect, reflected by the numbers of PFC and RFC and raised levels of cAMP. Inhibition of the adrenergic beta-receptor stimulated immunologic responses and lowered levels of cAMP in lymphocytes. Confirmation of a specific adrenergic mechanism was provided by the absence of an effect of stimulation after prior blocking of the receptor. The possibility of a nonspecific membrane effect of beta-adrenergic drugs is discussed.
Osmotic fragility of lymphocytes and erythrocytes isolated from the same blood sample was studied. Release of 51Cr from lymphocytes and erythrocytes under the influence of distilled water and solutions (NaC1 from 0-1% to 4% and 0-83% NH4C1) was compared.
125I-labeled Uropolin (syn. Uropolinum, Uromiro, Urografin) is bound to lymphocytes and erythrocytes if used to isolate lymphocytes in uropolin-dextran gradient. After 24-hr storage of 4 degrees C lymphocytes retained 60% of their radioactivity, and erythrocytes 87% under the same conditions.
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Using morphological and radionuclide methods the ability of engulfing and intracellular killing of Candida albicans cells by granulocytes of patients with atopic dermatitis was tested. The patients had moderately intense lesions without secondary infections. The results obtained by the morphological method, that is the percent of phagocytizing granulocytes, the percent of C. albicans cells engulfed by the granulocytes and the percent of killed C. albicans cells in the group of 25 patients and in the group of 25 controls were not statistically significantly different. The radionuclide method with 51Cr labelling of Candida albicans failed to demonstrate differences between 15 patients and 25 controls in the intracellular killing of these cells. No significant effect of the serum of healthy subjects on the functions of the granulocytes and no effect of the serum of the patients on granulocyte functions of controls were noted.