Holmium: yttrium-aluminum-garnet laser for endoscopic lithotripsy.

OBJECTIVES: To evaluate the holmium:yttrium-aluminum-garnet (Ho:YAG) laser for endoscopic lithotripsy on patients diagnosed with urinary tract calculi. METHODS: Thirty-eight procedures utilizing transurethral ureterolithotripsy or percutaneous nephroureteral lithotripsy were evaluated: 5 renal calculi, 31 ureteral calculi (most in the upper ureter), 1 ureteropelvic junction calculus, and 1 bladder calculus. These were mainly in cases that, after being treated with extracorporeal shock-wave lithotripsy (ESWL), were contraindicated for further ESWL. Laser parameters included energy of 0.5 to 1.0 J/pulse and pulse rate of 5 to 10 Hz. RESULTS: Composition of calculi was determined in 26 procedures. The Ho:YAG laser was effective for fragmenting all types of calculi. Patient outcome evaluated at 6 weeks after treatment showed that 33 of 38 procedures (87%) were effective. Residual calculi in 4 of the 5 unsuccessful procedures were less than 5 mm in size and judged to be able to pass spontaneously. In the remaining procedure, the calculus was passed spontaneously 3 months after treatment. No severe damage to tissues or adverse effects to the body were observed due to the Ho:YAG laser. CONCLUSIONS: On the basis of these results, we determine that this wavelength is effective for lithotripsy in addition to its previously reported usefulness for soft tissue applications, and, thus, is a cost-effective and highly useful clinical device.

An experimental model for advanced ovarian cancer.

Intraperitoneally transplanted tumors implanted and began developing with ascites in about 62% of the female rats within 4 to 6 weeks after transplantation. The tumor used in this study was an adenocarcinoma and which originated from a primary ovarian cancer in rats of the same strain (Wistar). The morphology and biological behavior of the tumor were very similar to the tumor in humans. Moreover, the preliminary results with cisplatin therapy indicate that intraperitoneal cancer corresponding to stage III or IV in the FIGO classification is a promising model for experimental therapeutic studies of common epithelial carcinoma at an advanced stage.

Characterization of transplant generations of primary rat adenocarcinoma and some chemotherapeutic observations.

Rats (Wistar) bearing subcutaneous implants of tumor fragment of DMBA-induced tumor were used in this study. Studies have been made of their proliferative characteristics, and their response to Cis-dichlorodiammine platinum (CDDP) has been measured. The transplanted tumor appears to be on homogeneous solid structure throughout all transplant generations, although the primary site is concomitant adenocarcinoma showing both glandular and solid structure. Microangiography showed that the transplanted tumor was more hypervascular than the primary tumor. Compared with the previous reports using the primary autochthonous tumor, the antitumor effect of CDDP is excellent and the histologic effect is observed in all areas of the sectioned surface. The transplanted tumor could provide a useful experimental system for the laboratory study of the chemotherapy of ovarian adenocarcinoma and the possibility of predicting ovarian adenocarcinoma seemed to be great because of the morphological similarity.

Intrasplenic grafting of 7,12-dimethylbenz (a) anthracene-treated ovarian piece.

Immediately after a direct application of a chemical carcinogen, 7,12-dimethylbenz (a) anthracene (DMBA), the ovarian piece containing DMBA was implanted into the spleen of Wistar strain rats with or without gonadectomy. Six months after these treatments, an intrasplenic neoplasm was found in four of nine gonadectomized rats and in two of ten rats without castration. The volume of the induced tumor in the former group was 1.85 cm3 in average and that in the latter was 0.25 cm3. Histologic examination indicated that all of the induced tumors were not in the sex cord-stromal category, but adenocarcinomas. No morphological differences between the tumors in the castrated group and those in the noncastrated group could be detected by light microscopy. From the difference in the volume and the incidence of the induced tumors in the two groups, it appears that the hyperstimulation of the pituitary gonadotropins in the castrated rats promoted the tumorigenic process of the induced 'epithelial' ovarian cancer caused by the DMBA application to the grafted ovarian pieces.