Moses technology in a stone simulator.

INTRODUCTION: The objective of this study was to compare fragmentation efficiency of the conventional regular mode of holmium laser to the Moses contact mode on a stone simulator. METHODS: The Lumenis® PulseTM P120 H holmium laser system, together with Moses D/F/L fibers were used to compare regular mode with Moses contact mode in a stone simulator model using flexible ureteroscopy with artificial stones. Efficiency of laser lithotripsy was measured by procedural time. Degree of stone retropulsion was also compared between regular and Moses modes using a Likert scale from 0 (no retropulsion) to 3 (maximum retropulsion). RESULTS: Using the stone simulator model, a significant reduction in stone retropulsion was noticed when comparing regular mode to the Moses contact mode (mean Grade 2.5 vs. Grade 1; p<0.01). When compared with the regular mode, the Moses contact mode was associated with significantly shorter procedural time during fragmentation (13.9 vs. 9.1 minutes; p≤0.01) and dusting (9.3 vs. 7.1 minutes; p≤0.01). In addition, when compared with the regular mode, the laser pedal was pressed significantly less often with the Moses mode during fragmentation (86 vs. 43 times; p<0.01) and dusting (50 vs. 26 times; p<0.01). Moses contact mode was associated with significantly higher percentage of lasing vs. pausing when compared with the regular mode for both fragmentation (0.8 J/10 Hz) and pulverization (0.4 J/50 Hz) settings (both p<0.05). CONCLUSIONS: Using the stone simulator setup, Moses technology was associated with more efficient laser lithotripsy (shorter operative time) due to significantly reduced stone retropulsion.

Does needle rotation improve lesion targeting?

BACKGROUND: Image-guided robots are manipulators that operate based on medical images. Perhaps the most common class of image-guided robots are robots for needle interventions. Typically, these robots actively position and/or orient a needle guide, but needle insertion is still done by the physician. While this arrangement may have safety advantages and keep the physician in control of needle insertion, actuated needle drivers can incorporate other useful features. METHODS: We first present a new needle driver that can actively insert and rotate a needle. With this device we investigate the use of needle rotation in controlled in-vitro experiments performed with a specially developed revolving needle driver. RESULTS: These experiments show that needle rotation can improve targeting and may reduce errors by as much as 70%. CONCLUSION: The new needle driver provides a unique kinematic architecture that enables insertion with a compact mechanism. Perhaps the most interesting conclusion of the study is that lesions of soft tissue organs may not be perfectly targeted with a needle without using special techniques, either manually or with a robotic device. The results of this study show that needle rotation may be an effective method of reducing targeting errors.

Effects of 6-mercaptopurine treatment on sperm production and reproductive performance: a study in male mice.

OBJECTIVE: Azathioprine and 6-mercaptopurine interact in purine metabolism and DNA synthesis, thus their potential mutagenic effects have been of concern in the management of inflammatory bowel disease (IBD), especially in patients of childbearing age. Although several clinical studies have indicated their safety in both reproduction and pregnancy, in a recent large epidemiological study concerns were raised about their adverse effects in pregnant patients with IBD, and experimental or basic data on this subject are limited. The aim of this study was to investigate sperm production, sperm quality, and reproductive outcome following prolonged 6-MP administration to male mice. MATERIAL AND METHODS: Highly inbred Balb/c adult male mice were used. 6-MP at doses of 2, 5, and 8 mg/kg (n = 9 for each group) was given daily for 51 days and the treatment group was compared with controls. After 45 days of treatment, the mice were mated with females. Following 13 days of pregnancy, the products of conception were evaluated and live fetuses were examined for gross malformations. Sperm production and morphology were examined after 51 days of 6-MP administration. RESULTS: Treatment with 6-MP at all doses did not affect sperm morphology and sperm production in the testicular tubules, as compared with controls (70% normal sperm). However, pregnancy rates were inversely related to escalating doses of 6-MP: 55%, 41%, 28%, and 16% for control, 2, 5, and 8 mg/kg groups, respectively. Resorption rates (abortions) were 21% in the control group as compared with 45-50% in all the treatment groups, but the incidence of major congenital malformations was not increased. CONCLUSIONS: Long-term 6-MP treatment in male mice did not impair sperm production and sperm morphology. However, a significantly high rate of embryonic resorption indicated occult sperm damage. Thus, normal sperm analysis does not necessarily imply that sperm damage at genetic level did not occur. It is difficult to extrapolate from these results to the clinical use of 6-MP/azathioprine in IBD patients; however, further basic genetic testing for DNA damage and clinical follow-up are warranted.