Choong S K, Wood S, Whitfield H N
Institute of Urology and Nephrology, London, UK.
BJU Int. 2000 Sep;86(4):414-21. doi: 10.1046/j.1464-410x.2000.00861.x.
To validate an encrustation model and to quantify encrustation on currently used urological devices and polymers intended for urological use. Materials and methods An encrustation model was validated: (i) to measure the amount of calcium leaching from the glass model and from the polymer used; (ii) to determine whether the use of a single-source or pooled urine produced similar results; (iii) to determine in vitro encrustation; and (iv) to compare the results of in vivo implantation of the same materials into the bladders of rodents with the in vitro results. A test polymer (a ureteric stent, a urethral catheter or a biomaterial) and a control silicone polymer were housed separately but received human urine from the same reservoir and under the same conditions (pH 6.0 and 37 degrees C) for 5 days. The amount of calcium encrustation on each polymer was measured using atomic absorption spectroscopy. Each experiment was repeated at least four times and the results expressed as an encrustation index, defined as the ratio of encrustation of the test and reference polymers.
The amount of calcium leaching from the glass model and polymers tested was insignificant. The use of a single-source or pooled urine gave the same results in the encrustation model. The in vitro results correlated with in vivo implantation of disks into the bladders of rats. Among the commonly used ureteric stents tested, the Cook C-Flex ureteric stents encrusted least. Hydrogel-coated ureteric stents encrusted more than uncoated stents. The Bard polytetrafluoroethylene short-term urethral catheter encrusted more than the Bard hydrogel-coated long-term catheter. A plasma-activated surface modification of a synthetic biomaterial with hyaluronic acid encrusted less than silicone, a long-term biomaterial widely regarded as the 'gold standard'.
This validated encrustation model is the first to quantify encrustation on currently available ureteric stents and urethral catheters. A novel coating for a biomaterial was identified using the encrustation model, and which encrusted less than silicone.
验证一种结壳模型，并对当前使用的泌尿外科器械以及用于泌尿外科的聚合物上的结壳进行量化。材料与方法 一种结壳模型得到验证：(i) 测量从玻璃模型和所用聚合物中浸出的钙量；(ii) 确定使用单源尿液或混合尿液是否产生相似结果；(iii) 确定体外结壳情况；(iv) 将相同材料在啮齿动物膀胱内的体内植入结果与体外结果进行比较。一种测试聚合物（输尿管支架、尿道导管或生物材料）和一种对照硅酮聚合物分别放置，但在相同条件下（pH 6.0和37摄氏度）从同一储液器接收人尿液5天。使用原子吸收光谱法测量每种聚合物上的钙结壳量。每个实验至少重复四次，结果以结壳指数表示，结壳指数定义为测试聚合物与参比聚合物的结壳率之比。
从玻璃模型和测试的聚合物中浸出的钙量微不足道。在结壳模型中，使用单源尿液或混合尿液得到相同结果。体外结果与将圆盘植入大鼠膀胱的体内植入结果相关。在所测试的常用输尿管支架中，库克C-Flex输尿管支架结壳最少。水凝胶涂层输尿管支架比未涂层支架结壳更多。巴德聚四氟乙烯短期尿道导管比巴德水凝胶涂层长期导管结壳更多。用透明质酸对合成生物材料进行等离子体活化表面改性后，其结壳比硅酮少，硅酮是一种被广泛视为“金标准”的长期生物材料。
这种经过验证的结壳模型首次对目前可用的输尿管支架和尿道导管上的结壳进行了量化。使用该结壳模型确定了一种新型生物材料涂层，其结壳比硅酮少。
