Use of an Anti-ras Ribozyme to Alter the Malignant Phenotype of a Human Bladder Cancer Cell Line:

Evaluation of fragmentation with single or multiple pulse setting of Lithoclast for renal calculi during percutaneous nephrolithotripsy and its impact on clearance

OBJECTIVES

To evaluate the impact of single or multiple pulse settings of Lithoclast to fragment renal calculi, and its effect on fragment size and clearance.

MATERIAL AND METHODS

In a prospective study 153 patients, who had been treated over a period of 35 months for renal stone disease by percutaneous nephrolithotomy, were evaluated. In 69 cases the single and in 84 cases the multiple pulse modes were used to fragment the stone intracorporeally using the pneumatic lithoclast. The 2 groups were similar with regard to patient characteristics, stone location and size.

RESULTS

Most stones were staghorn. The lithoclast was effective with good fragmentation in all cases. The mean operating and fluoroscopy times in the single and multiple pulse mode were 124.1 and 5.8, and 141.2 and 7.4 min, respectively (both differences statistically significant, p < 0.001). Immediate postoperatively residual stone fragments were seen in 16 cases with the single and 35 cases with the multiple pulse mode setting (difference statistically significant, p < 0.05). Relook procedures were required in 14 cases with the single and 22 cases with the multiple pulse setting (difference not statistically significant). No specific complication was seen related to the use of either of the two modes. On follow-up 1 patient in the multiple pulse setting developed stone recurrence after 19 months.

CONCLUSIONS

The single pulse mode was associated with controlled fragmentation of the stone, formation of larger fragments which were easier to pick up, less stone scatter, shorter operating time and less exposure to fluoroscopy. The single pulse mode was also associated with statistically less chances of postoperative residual fragments.

Hammerhead ribozymes as therapeutic agents for bladder cancer

Hammerhead ribozymes have been investigated extensively as therapeutic agents against cancer. Aberrant or overexpression of genes related to tumorigenicity or cancer growth might be the appropriate targets for ribozyme strategies. Ribozyme-mediated gene therapy should be applied to those diseases that have no successful conventional therapy such as advanced or treatment-resistant bladder cancer. Many genetic alterations have been identified in bladder cancer related to both tumorigenesis and disease progression. Mutated H-ras, fos, and erb-B2 genes have been chosen as targets for ribozymes in previous studies, and antitumor efficacy has been demonstrated by reversion of the malignant phenotypes and by inhibition of tumor growth both in vitro and in vivo. The efficiency of various delivery systems has also been evaluated. An overview of ribozyme strategies, especially for therapeutic applications against bladder cancer, is described here.