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.

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.

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.

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.

Determination of Calcium Accretion by External Measurements of 47Ca

The possibility of determining the calcium accretion rate by external measurements of the forearm activity and by plasma activity measurements was investigated. On the basis of these measurements and the Bauer kinetic model the index of accretion rate in the measured part of the forearm was determined. The values obtained were compared with the whole-body accretion rate values. It was found that the correlation coefficient for the body accretion rate reduced to 1 kg body weight was 0.961. The possibility of using the index of the accretion rate for the determination of the whole-body accretion rate is discussed as well as the advantages and disadvantages of determining the body accretion rate in this way.