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Biomedical subjects

S Popovic

Publications and source records attributed to S Popovic.

17 recordsLinked to original sources
PubMed2006

In vitro assay for the quantitative measurement of apoptotic lymphocytes phagocytosis by peripheral blood monocytes.

Currently used assays for the quantification of apoptotic cells uptake by phagocytes have several methodological problems. Our assay overcomes some of these problems. As a source of apoptotic cells we used peripheral blood lymphocytes obtained from the patients with chronic lymphoblast leukaemia. Apoptosis was induced by incubating cells with cycloheximide for up to 24 h. The assay was performed in suspension of peripheral blood mononuclear cells. For the visualisation of the phagocytes and phagocyted cells and discrimination of phagocyted from bound apoptotic cells we used Acridine orange/Ethidium bromide double staining. Here we offer a simple test which enables reliable measurement and it can show the difference of phagocytic potential between different individuals.

Apoptosis↗
PubMed2005

Human fetal islet transplantation in type 1 diabetics: comparison of immunological effects between multiple implantation regimens.

Previous studies have suggested that the multiple transplants might be equally metabolically efficient to a single regimen for human adult islets. The aim of this study was to compare immunological and metabolic parameters after each of the two regimens of human fetal islets (HFI). Group A single transplants (n = 9) had 180 +/- 20 x 1000 HFI equivalents (IEQs) implanted via a single intramuscular injection. In group B multiple transplants (n = 8) islets were implanted by three consecutive injections of 60 +/- 10 x 1000 IEQs at 7-day intervals. We analyzed the immunological parameters of CD4/CD8 T lymphocyte ratios; islet cell antibodies (ICAs) and insulin antibodies (IAs). We estimated insulin secreting capacity (ISC) as the metabolic parameter. We observed that the CD4+/CD8+ T-cell ratio increased, peaking on day 90, in similar fashion in both groups: day -1: A = 1.18 +/- 0.03 versus B = 1.19 +/- 0.04; on day 90: A = 1.79 +/- 0.09, versus B = 1.75 +/- 0.08 (P = NS) immediately before the decrease in C-peptide levels. Thereafter the ratios rapidly decreased without statistical differences. The levels of ICAs did not change. The levels of IAs, which were increased before transplant, then decreased without statistical differences between the groups. The values of ISC increased after transplant and then decreased similar to the T-cell ratio. Our results demonstrated that regimens of multiple and single HFIs did not show differences in the kinetics of the immunological response presumably mediating graft destruction. The CD4/CD8 ratio increased as the C-peptide level decreased, peaking on day 90 at the time of a decrease in C-peptide. These results may be useful for clinical studies of HFIs for type 1 diabetic patients.

CD4-CD8 Ratio↗
PubMed1999

Solid State Transitions of Asymmetric Catanionic Surfactants.

A series of asymmetric surfactants were prepared from cationic surfactant, hexadecyltrimethylammonium bromide, and anionic surfactant, sodium alkyl sulfate (the number of carbon atoms per chain being 10, 12, or 14). The influence of the alkyl chain asymmetry on the thermal properties of formed hexadecyltrimethylammonium alkyl sulfates was investigated by means of polarizing microscopy, differential scanning calorimetry, and X-ray diffraction. Asymmetric catanionic surfactants exhibited a complex polymorphism and thermotropic mesomorphism from the stable crystalline form to the isotropic phase. On heating, successive phase transitions (several solid crystalline-solid crystalline, solid crystalline-liquid crystalline, and liquid crystalline-isotropic liquid) were observed. The number of polymorphs, in all of the bilayered structure, depended on the asymmetry between the lengths of surfactant tails. The basic lamellar thickness varied linearly with the increase of alkyl sulfate chain length. An increase of the basic lamellar thickness with temperature was determined. Polarizing microscopy revealed a characteristic texture of the smectic phase. On cooling, all compounds underwent reversibly the isotropic liquid-liquid crystalline transitions, while crystallization from melted samples was kinetically controlled. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Differential effects of in vivo cadmium administration on lymphocytes and granulocytes in rats.

Effect of in vivo administration of 0.5, 1 or 2 mg cadmium/kg body mass on peripheral blood polymorphonuclear leukocyte and splenic lymphocyte functional state and viability was examined in rats. Decreased proliferative capacity in vitro of splenic lymphocytes to T-cell mitogen concanavalin A was noted at all administered cadmium dosages. No changes in cell viability, except at the highest cadmium dose, were noted in lymphocyte cultures. Increase in some of the aspects of granulocyte function including spontaneous adhesion and activation was seen and was accompanied by increase in granulocyte survival ex vivo. Rise in cytokine inflammatory mediators which might influence lymphocyte and neutrophil functions was noted also. Differential effects of cadmium on these 2 cell types might be considered when studying in vivo cadmium toxicity.

Animals↗
PubMed1988

Development of autoimmunity in MRL/lpr mice and the effects of drugs on this murine disease.

MRL/lpr mice spontaneously develop a systemic Lupus erythematosus (SLE)-like disease with a wide range of clinical and serological characteristics that mimic not only human SLE but other autoimmune disorders. such as Sjögren's syndrome, and rheumatoid arthritis (RA). Unlike other murine SLE-like disorders, these mice have circulating rheumatoid factor (RF) and develop histological changes in their joints. Therapy of this disease with cyclophosphamide (CY), cyclosporin A, prednisolone, or leflunomide (HWA 486) resulted in very differing effects. Treating these mice with HWA 486 or cyclophosphamide (CY) resulted in a decrease in the amount of autoantibodies, and immune complex deposits on the glomeruli. HWA 486 therapy led to restoration of the depressed immune response of MRL/lpr mice. In the established disease, prednisolone (Pr), cyclosporin A (CSA), and HWA 486 could inhibit the proteinuria and return the urine-protein values to normal levels, but, unlike HWA 486, neither PR nor CSA could extend the longevity of these animals. The MRL/lpr mouse should prove to be very useful as a model for SLE, RA, and for discovering novel drugs to combat such disorders.

Animals↗
PubMed1987

The use of the murine chronic graft vs host (CGVH) disease, a model for systemic lupus erythematosus (SLE), for drug discovery.

Studies were conducted to evaluate the use of a murine SLE-like disease for the discovery of novel drugs: This disease is the result of a chronic form of a graft vs host (GVH) reaction. Using prednisolone (Pr), cyclophosphamide (Cy), indomethacin (Indo), and the isoxazol derivative, HWA 486, we found that only Indo was ineffective in inhibiting the SLE symptoms. Interestingly, HWA 486, which did not display any immunosuppressive activity, restored the suppressed T-cell response to the same level as found in healthy mice. We feel that this murine model of SLE could be of value for discovering substances with novel antirheumatic, and/or immunomodulating activities.

Animals↗
PubMed1976

[Effectiveness of oxyclozanide in cattle naturally invaded by Liorchis scotiae trematoda].

The paper reports on the results of the clinical tests for the effectiveness of oxyclozanide pure substance (produced by ICI, U.K.) in cattle naturally invaded by the paramphistomata Liorchis scotiae. Helminthological dissection, performed 21 days after a single application of 15 mg oxyclozanide per 1 kg 1. w., revealed 87.5% intenseffectiveness on sexually mature paramphistomata on 85% intenseffectiveness on juvenile paramphistomata. The extenseffectiveness of the chemical was equal to zero. The coprological examinations performed for the three weeks in one-week intervals after therapy showed a decline in the number of produced eggs. The animals were given the medicated feed containing oxyclozanide only after preceding starvation. The chemical did not produce any unfavourable side effects or signs.

Animals↗