Reactions of Metal Carbides to Produce Carbon

Calcium carbide was historically used to reduce potassium metal from potassium fluoride as described in a 1922 patent. This was prior to the discovery of electrolytic synthesis, which replaced the carbide process in less than five years. A byproduct of this process was elemental carbon. This carbon was unanalyzed at the time. The object of this research was to analyze carbon produced in reactions similar to this and to determine if this reaction could be carried out under milder conditions. It was found that the reaction is part of a family of reactions, and would proceed with a number of other salts, including zinc chloride, stannous chloride, and stannous fluoride. The carbon produced via molten salt reactions was irregular, and primarily amorphous. The reactions could take place in a solvent at room temperature. Carbon produced via solvent-phase reactions was more orderly and primarily graphitic. Finally, the reactions could take place in a galvanic cell, separating the reactions into two half reactions. This configuration had numerous benefits: reaction rates could be measured via current, metallic byproducts are produced in a separate cell from carbon simplifying purification, and morphology of carbon was more regular. Almost no amorphous carbon was produced in this configuration. The carbon produced in solvent-phase reactions, both simple solvent-phase and galvanic cell, showed unusual morphology. Highly ordered, hexagonal crystals were found throughout all solvent-phase reaction products. These crystals were shown to be highly ordered via Raman spectroscopy. Future work should be focused on synthesizing carbides to reduce contaminant concentration, synthesizing commercially unavailable carbides, and attempts to isolate and exfoliate hexagonal crystals to graphene

Thymoglobulin Induction Dosing Strategies in a Low-Risk Kidney Transplant Population: Three or Four Days?

The optimal dose and duration of rabbit antithymocyte globulin (rATG) induction has not been defined. Methods. We compared the safety and efficacy of 2 dosing strategies, rATG 1.5 mg/kg for 4 days (n = 59) versus 2 mg/kg for 3 days (n = 59), in a retrospective, cohort study. Results. Two-year rejection-free survival was 95% in each group (P = .983). Renal function and infection rates were similar. The incidence of leucopenia was similar, although the 2 mg/kg group was more likely to be thrombocytopenic on day 2 (4% versus 28%, P = .04). Length of stay tended to be longer for the 1.5 mg/kg group (6.0 ± 3.7 versus 5.1 ± 1.9 days P = .104). A cost savings of $920 per patient for rATG were seen in the 2 mg/kg group (P = .122). Conclusions. Shorter, more intense dosing of rATG is safe and effective. The 3-day dose strategy resulted in a clinically shorter length of stay and may result in cost savings

Should heart, lung, and liver transplant recipients receive immunosuppression induction for kidney transplantation?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74619/1/j.1399-0012.2009.00973.x.pd

Late Plasma Cell Depletion After Thymoglobulin Induction in Kidney Transplant Recipients

Objectives: Induction therapy with rabbit antithymocyte globulin is frequently used in kidney transplant recipients and contributes to regulating the humoral alloantibody response. However, the effect of rabbit antithymocyte globulin on B-cell subpopulations, including plasma cells, has not been previously studied in humans in vivo. Materials and methods: We prospectively studied a cohort of 39 adult kidney transplant recipients. Twenty patients received rabbit antithymocyte globulin as induction therapy. Peripheral blood samples were obtained pretransplant and at 6 and 12 months posttransplant. T and B cells were acquired by flow cytometry. Results: Total lymphocytes and CD3 and CD4 cells significantly decreased at 6 and 12 months only in patients who received rabbit antithymocyte globulin. In contrast, the CD19 population did not change after rabbit antithymocyte globulin induction. One-year circulating plasma cells remained significantly lower than pretransplant levels in patients who received rabbit antithymocyte globulin. We observed sig-nificant differences in plasma cell numbers at 12 months after transplant between patients who received rabbit antithymocyte globulin and those patients who did not receive it (median of 5 and interquartile range of 3-17 vs median of 25 and interquartile range of 12-35; P = .001). Conclusions: Rabbit antithymocyte globulin induction leads to a late reduction in the number of circulating plasma cells at 1 year after kidney transplant. This effect can contribute to down-regulation of the humoral alloantibody response

Targeting of Natural Killer Cells by Rabbit Antithymocyte Globulin and Campath-1H: Similar Effects Independent of Specificity

T cell depleting strategies are an integral part of immunosuppressive regimens widely used in the hematological and solid organ transplant setting. Although it is known to induce lymphocytopenia, little is known about the effects of the polyclonal rabbit antithymocyte globulin (rATG) or the monoclonal anti-CD52 antibody alemtuzumab on Natural Killer (NK) cells in detail. Here, we demonstrate that induction therapy with rATG following kidney/pancreas transplantation results in a rapid depletion of NK cells. Treatment of NK cells with rATG and alemtuzumab in vitro leads to impairment of cytotoxicity and induction of apoptosis even at a 10-fold lower concentration (0.1 µg/ml) compared with T and B cells. By generating Fc-parts of rATG and alemtuzumab we illustrate that their ligation to FcγRIII (CD16) is sufficient for the significant induction of degranulation, apoptosis and inflammatory cytokine release (FasL, TNFα and IFNγ) exclusively in CD3−CD56dim NK cells whereas application of rATG and alemtuzumab F(ab) fragments abolishes these effects. These findings are of general importance as our data suggest that NK cells are also mediators of the clinically relevant cytokine release syndrome and that their targeting by therapeutic antibodies should be considered as they are functionally relevant for the effective clearance of opportunistic viral infections and anti-tumor activity posttransplantation