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Biomedical subjects

H C Gunn

Publications and source records attributed to H C Gunn.

12 recordsLinked to original sources

Accuracy of continuous jugular bulb venous oximetry during intracranial surgery.

We compared readings obtained from the Baxter-Edwards continuous jugular bulb venous oximetry catheter with those obtained from blood gas analysis of simultaneously drawn samples from the catheter in 12 patients undergoing neurosurgical procedures. Within the range studied (SjvO2, 42-95%), the 111 (median, nine samples per patient; range five to 17) oximetric catheter readings correlated well with hemoglobin oxygen saturation values obtained from in vitro analysis of simultaneously drawn blood samples from the catheter (y = 0.93x + 3.4, r = 0.94, p < 0.001). Fiberoptic light signal was suboptimal (signal quality index = 3 or 4) on fewer than five occasions per patient during an average surgical procedure duration of seven h, and these occurrences were generally corrected by flushing the catheter. We conclude that the Baxter-Edwards jugular bulb oximetric catheter provides an accurate measure of SjvO2 during neurosurgical procedures.

Adult

Successful treatment of autoimmunity in (NZB X NZW)F1 mice with cyclosporin and (Nva2)-cyclosporin: I. Reduction of autoantibodies.

Autoimmune (NZB X NZW)F1 mice were treated with the immunosuppressive agent, cyclosporin, and its new derivative (Nva2)-cyclosporin. Both compounds prevented the development of autoantibodies in young mice, and also reduced the levels of the autoantibodies in old mice. These findings established that autoantibodies, at least in the (NZB X NZW)F1 mice, can be controlled pharmacologically. This study supports the possibility that treatment with cyclosporin and (Nva2)-cyclosporin might be effective in the treatment of certain autoimmune diseases in man.

Age Factors

Glomerulonephritis in NZB/W mice: therapeutic effect of cyclosporine.

Female NZB/W hybrid mice spontaneously develop autoimmune glomerulonephritis (GN) at the age of 3 to 6 months. The aim of the present study was to investigate the effects of cyclosporine (CS) on proteinuria and GN in mice at various stages of the disease, e.g., 12, 24 and 48 weeks of age. A 12 week course of CS (100 mg/kg/day) either abolished or prevented the development of proteinuria depending on the disease stage. Histologically, CS prevented the further development or even reversed GN. Immunoglobulin (Ig) and complement (C') deposition in the glomeruli were also reduced in CS-treated mice. These results indicate that CS has a therapeutic effect in murine autoimmune GN.

Age Factors

Successful treatment of autoimmunity in (NZB X NZW)F1 mice with cyclosporin and (Nva2)-cyclosporin: II. Reduction of glomerulonephritis.

Autoimmune (NZB X NZW)F1 mice were treated with the immunosuppressive agent, cyclosporin, and its new derivative (Nva2)-cyclosporin. Both compounds prevented the deposition of immunocomplexes in the kidneys, and the subsequent development of glomerulonephritis and proteinuria in young mice. They also reduced established proteinuria in old mice. Therefore, we feel that both cyclosporin and (Nva2)-cyclosporin may be useful in the treatment of human glomerulonephritis where there is an autoimmune component.

Age Factors

Comparison of the pharmacological profiles of cyclosporine, (Nva2)-cyclosporine and (Val2)dihydro-cyclosporine.

The pharmacological profiles of two new derivatives of the immunosuppressive drug, cyclosporine, is presented here. (Nva2)-CS has very similar properties to CS, but lacks the nephrotoxic side-effects. This derivative appears to be a potential successor to cyclosporine. (Val2)DH-CS seems to have a different spectrum of activities. It does not suppress humoral immunity and allograft rejection, but suppresses some types of cell-mediated immune responses. This derivative may prove useful in autoimmune situations where T cells are involved in the disease process.

Animals

Murine T cell suppression demonstrable in the absence of cytotoxicity and the effect of Cyclosporin A on this system.

In vitro culture of murine spleen cells in FCS without prior immunization or allogeneic stimulation leads to the development of spontaneous cytotoxicity. This cytotoxicity is not H-2 restricted and can affect any subsequent in vitro assays using syngeneic cells, especially if those assays include prolonged culture in FCS. Studies on murine spleen cells cultured in NMS, however, led to the detection of a suppressor system that did not display cytotoxic effects. Furthermore, it was found that this suppression, in contrast to the cytotoxicity and suppression generated during culture in FCS, was not sensitive to CYA. The suppressor cell may be an effector or an inducer of suppression and is sensitive to treatment with anti-Thy-1.2 and complement. It is suggested that some in vitro suppression is really due to cytotoxicity that may be directed toward FCS determinants adsorbed onto syngeneic targets.

Animals