Study Of Cefotaxime On Transmembrane Behavior Of Ca²⁺ In Cell

Chapter 1:The distribution and function of calcium ion in human body were described. The principle and measurement methods of Ca2+ concentration were also discussed. Besides, the spectra character and application of calcium fluorescence probe were reviewed.Chapter 2:The interaction of Fura-2 and Ca2+ in different temperatures and pH conditions was investigated using fluorescence spectra method. The apparent dissociation constants (Kd) of Fura-2-Ca2+ were calcuLated by equation, meanwhile, the thermodynamics parameters were determined through thermodynamics equation. The resuLts suggested that Fura-2 is a crediable Ca2+-sensitive fluorescence probe for [Ca2+]i measurements in a large range of temperatures. But some errors wouLd be made in alkaline conditions. The thermodynamics study showed that the combination of Fura-2 and Ca2+is endothermic and spontaneous reaction, the increased temperature make the formation of Fura-2-Ca2+ easier. Combine with optimal condition 37℃and pH7.5 were chosen to be the best conditions for experiment.Chapter 3:Using ratio fluorescent technique with a ratiometric fluorescent dye-Fura-2, we had studied the effects of Cefotaxime (CTX) on intracelluLar Ca2+ concentration ([Ca2+]i) of human peripheral lymphocytes and rat marrow tumour cell. The mechanism of calcium transporting was as follows:0.005 g/L CTX led to the decrease of [Ca2+]i trough phosphatidylinositol transduction pathway, when the concentration came to 0.5 g/L, [Ca2+]i decreased perhaps because of Calcium pump. In rat marrow tumour cell, the addition of different concentrations of CTX made dose-independent decrease of [Ca2+]i perhaps because of the Ca2+-APTase in memberane.Chapter 4:Ca2+-ATPase reagent-box was used to determinate the activity of Ca2+-ATPase in human lymphocytes and rat marrow tumour cell which father approved that the decrease of [Ca2+]i in human lymphocytes and rat marrow tumour cell were achieved through calcium pump. After the addition concentration of CTX come to 0.5 g/L, [Ca2+]i in human lymphocytes are likely to be expelled from cytoplasm through calcium pump in membrane of. as for the rat marrow tumour cell, the decrease of [Ca2+]i maybe achieved by the mix-effect of calcium pump of membrane in cell and the calcium store.