Arylsulfatase A in urine of patients with urothelial tumors

A significant increase in urine arylsulfatase A activity (p less than 0.01) was found in patients with urothelial tumors. Arylsulfatase A activity was 1.36 +/- 1.10 U/24-h urine in control specimens, 1.90 +/- 1.66 U/24-h urine in various genitourinary tract disorders, and 3.90 +/- 1.98 U/24-h urine in transitional cell carcinoma specimens. Surgical treatment of the neoplastic patients lowered the arylsulfatase A activity found in urine to within reference values. The arylsulfatase A excreted by patients with these tumors was highly sensitive to thermal inactivation while the enzyme activity in the control urines was less affected by the heat treatment. The time course of the arylsulfatase A reaction with 4-nitrocatechol sulfate was not linear in normal individuals, while it was linear in 90% of patients with urothelial tumors. This difference in the kinetic pattern of the enzyme could be used to increase the diagnostic specificity of the determination.     

The glycine receptor: pharmacological studies and mathematical modeling of the allosteric interaction between the glycine- and strychnine-binding sites

The displacement by glycine of 3H-strychnine binding to rat spinal cord membranes cannot be explained by a simple competitive interaction. Indeed, protein-modifying reagents can completely abolish the inhibition of 3H-strychnine binding by glycine and other agonists, whereas the interaction of strychnine itself and other related compounds with the binding site is unimpaired. Moreover, glycine cannot inhibit completely saturable 3H-strychnine binding, the extent of its maximum inhibitory effect depending on the ionic composition of the medium. Hill coefficients less than 1 (whose magnitude also depends on the assay medium) were obtained from glycine displacement curves. These properties are consistent with a mathematical model of two different, but mutually interacting, binding sites for strychnine and glycine on the glycine receptor. The effect of ions and protein-modifying reagents might be explained in this model as modifications of the mechanisms that mediate the allosteric interaction, and/or the affinity of glycine for the receptor. The agonists beta-alanine and taurine and the new antagonists, THAZ, iso-THAZ, and 4,5-TAZA, also seem to interact with a site different from the strychnine-binding site, probably the glycine-binding site.     

高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数

本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4～5.6%,血浓69.6～1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。