(Bio-)remediation of VCHC contaminants in a Technosol under unsaturated conditions.

The remediation of dense non-aqueous phase liquids has always been a concern of both public and scientific interest groups. In this research work a modified physical concept of (bio)remediation of a volatile chlorinated hydrocarbon (VCHC) contamination was elaborated under laboratory conditions and modeled with HYDRUS-2D. In field dechlorination is influenced by both physicochemical and hydraulic properties of the substrate, e.g. texture, pore size distribution, pore liquid characteristics, e.g. viscosity, pH, surface tension, and dependent on the degree of saturation of the vadose zone. Undisturbed soil cores (100 cm³) were sampled from a Spolic Technosol. Considering hydraulic properties and functions, unsaturated percolation was performed with vertically and horizontally structured samples. VCHC concentrations were calculated prior, during, and after each percolation cycle. According to laboratory findings, microemulsion showed the most efficient results with regard to flow behavior in the unsaturated porous media and its accessibility for bacteria as nutrient. The efficiency of VCHC remediation could be increased by the application of a modified pump-and-treat system: the injection of bacteria Dehalococcoides ethanogenes with microemulsion, and extraction at a constant matric potential level of -6 kPa. Achieved data was used for HYDRUS-2D simulations, modeling in situ conditions, demonstrating the practical relevance (field scale) of performed unsaturated percolation (core scale), and in order to exclude capillary barrier effects.

Cyclosporine effect on anti-CD3 monoclonal antibody-stimulated mitogenesis, phorbol ester comitogenesis, and PGE2 production.

Human peripheral blood mononuclear cells (H-PBMC) from 10 healthy donors were stimulated to proliferate with phytohemagglutinin lectin (PHA), anti-CD3 monoclonal antibody (mAb), and anti-CD3 mAb plus phorbol 12, myristate 13 acetate (TPA), a protein kinase C (PKC) agonist. Anti-CD3 mAb-mediated mitogenesis was 35-75% of that observed with PHA. When TPA was added to a dose of mAb that by itself did not cause mitogenesis, proliferation equal to 50-90% of the maximally mitogenic dose occurred. TPA did not enhance proliferation with maximally mitogenic doses of antibody. Dimethyl-prostaglandin E2, dibutyryl cyclic AMP, and forskolin (an adenyl cyclase agonist) inhibited PHA, anti-CD3, and anti-CD3/PMA-mediated mitogenesis. Cyclosporine (CSA) inhibited anti-CD3 and anti-CD3/TPA mitogenesis in a dose-dependent fashion. While CSA inhibited anti-CD3 and anti-CD3/TPA mitogenic signals, it did not affect PGE2 production by anti-CD3 mAb-stimulated H-PBMC. In the presence of CSA, PGE2 production in PHA-stimulated H-PBMC was increased. PGE2 inhibits lymphocyte proliferation via a cyclic AMP-mediated mechanism and may enhance maturation of suppressor cells. CSA inhibits anti-CD3 mAb and anti-CD3/TPA proliferative signals in H-PBMC yet has no effect or may even enhance production of suppressive PGE2. The maturation of antigen-specific suppressor cells elicited by CSA may involve active down-regulation of CD3 receptor and PKC-dependent events while PGE2 production continues.

The effect of verapamil on cellular uptake, organ distribution, and pharmacology of cyclosporine.

Verapamil has been shown to potentiate cyclosporine's effect in inhibiting lectin-stimulated proliferation of murine and human lymphocytes, and in prolonging graft survival in experimental heterotopic cardiac transplantation in rats. A series of experiments were designed to determine whether verapamil's effect occurred by increasing cyclosporine uptake or decreasing cyclosporine's clearance by lymphocytes utilizing human peripheral blood lymphocytes and radiolabeled cyclosporine. Verapamil had no effect. The distribution of radiolabeled cyclosporine was also studied in mice that had been given verapamil (10 mg/kg) 1 hr prior to cyclosporine injection. No significant changes in organ distribution occurred. Lectin-stimulated release of intracellular ionized calcium was studied using a flurometric technique (Quin-2 and Fura-2). Neither cyclosporine nor verapamil had any effect on either lectin-stimulated or phorbol ester-stimulated release of intracellular ionized calcium. Phorbol ester and subproliferative doses of lectin were used to determine the effect of cyclosporine and verapamil on protein kinase C-mediated lymphocyte activation. Cyclosporine inhibited phorbol ester stimulated proliferation and verapamil potentiated this inhibition. Verapamil does not change cell or organ uptake of cyclosporine, and it does not affect the initial increase in intracellular ionized calcium that occurs with lymphocyte activation. Verapamil potentiates cyclosporine in inhibiting protein kinase C-mediated events in lymphocyte activation.