Telomerase activity in prostate sextant needle cores from radical prostatectomy specimens.

Human telomerase acts to maintain functioning telomeres, which are required for cellular immortality and very likely for cancer progression. Telomerase activity is present in about 85% of human cancers tested, but it has not been found in most human somatic cells and tissues. We used the Telomeric Repeat Amplification Protocol to perform telomerase activity assays on sextant needle core samples obtained from 35 freshly excised radical retropubic prostatectomy specimens. Similar assays were done on prostatic tissues obtained by means of other urologic procedures from 8 patients without prostate cancer. Telomerase activity was found in one or more specimens from 32 of 35 prostate cancer patients (91%), but was not detectable in all biopsy specimens from 7 of 8 cancer-free patients (88%). Further analysis showed that cancers more poorly differentiated, with higher Gleason scores, were always associated with a higher rate of telomerase detection and stronger telomerase activity. Moreover, comparison of telomerase activity in needle core samples with the volume of cancer in surrounding tissue as observed on corresponding histologic slides showed that stronger activity was positively correlated with a higher cancer volume. Prognostic indicators of prostate cancer and the expression of telomerase appear to be linked. The presence of telomerase activity in prostate tissue may aid in the detection of prostate cancer and produce additional prognostic information.

Effect of pyridine on the expression of cytochrome P450 isozymes in primary rat hepatocyte culture.

In vivo administration of pyridine has been shown to increase the activity and content of several forms of cytochrome P450 by transcriptional and posttranscriptional mechanisms. The effect of pyridine on CYP1A and CYP2E1 isozymes was studied in a rat hepatocyte culture model. Hepatocytes were isolated from non-induced rats and seeded onto matrigel-coated dishes and incubated in William's medium E containing 10% fetal calf serum, hormones, and essential metals. Cultures were treated with 0, 10 or 25 mM pyridine for 1-3 days and microsomes were isolated to determine catalytic activity and for immunoblot analysis, and total RNA was isolated for mRNA determinations. CYP2E1 content, CYP2E 1 mRNA, and CYP2E1 catalyzed oxidation of p-nitrophenol declined during culture to values of 3, 30 and 19% that of initial, non-cultured controls by day 3 of culture. Pyridine prevented this decline of CYP2E1 protein and activity such that 60-80% original activity remained after 3 days of culture in the presence of 25 mM pyridine. However, pyridine did not prevent the fall in CYP2E1 mRNA levels, nor did pyridine increase the content or activity of CYP2E1 above initial values of microsomes from freshly isolated hepatocytes. Pyridine increased the content of CYP1A2 and the oxidation of ethoxyresorufin 2-4 fold compared to cultures incubated without pyridine over the 3 day culture period. CYP1A1 levels, which rapidly declined, were induced and maintained in the presence of pyridine. Pyridine increased CYP1A content and activity 2-3 fold over initial values of freshly isolated hepatocytes. These increases were associated with corresponding increases in CYP1A mRNA levels. CYP1A2, but not CYP1A1, mRNA levels increased in the cultures incubated in the absence of pyridine. These results indicate that pyridine has different effects on CYP1A and CYP2E1 in this hepatocyte culture model. Pyridine appears to modulate CYP2E1 levels by posttranscriptional mechanisms as CYP2E1 activity and content were maintained in the presence of pyridine under conditions in which CYP2E1 mRNA levels declined. These mechanisms may involve increased translational efficiency of existing CYP2E1 mRNA or stabilization of CYP2E1 protein against degradation. Pyridine increased CYP1A1 and CYP1A2 content, activity and mRNA levels, either inducing CYP1A transcription or stabilizing CYP1A mRNA. Hepatocyte cultures may be a useful model to study the interaction of pyridine with P450 isozymes and their associated drug-mediated toxicity.

Endoscopic treatment of continent urinary reservoir calculi.

Formation of calculi is a late complication of continent urinary diversions. The techniques of percutaneous and transstomal treatment of these stones are described. Three patients underwent percutaneous placement of a rigid nephroscope into three different types of continent reservoirs and fragmentation of stones (2-5 cm in size) using ultrasonic lithotripsy. Preoperative CT scan of the abdomen and pelvis with oral and intrareservoir contrast was essential in finding the safest location for percutaneous access. One patient, with small stones, underwent placement of a flexible cystoscope through the continent efferent limb and Holmium laser lithotripsy. There were no instances of reservoir perforation. There was minimal blood loss, with an average operative time of 165 min. Ultrasonic lithotripsy of large stones through a percutaneous approach and Holmium laser lithotripsy for smaller stones via a flexible cystoscope placed through the efferent limb are safe and effective ways to treat calculi within continent urinary diversions.

Laparoscopic pelvic lymph node dissection combined with real-time interactive transrectal ultrasound guided transperineal radioactive seed implantation of the prostate.

Laparoscopic pelvic lymph node dissection with real-time interactive transrectal ultrasound guided transperineal radioactive seed implantation is a new method of treatment for localized carcinoma of the prostate. A total of 58 patients with clinically confined prostate cancer and negative seminal vesicle biopsies underwent staging laparoscopic pelvic lymph node dissection immediately followed by prostate implantation: 50 had 125iodine and 8 had 103palladium implants. Mean operating time was 226 minutes (range 120 to 475), mean blood loss was 57 cc (range 5 to 400) and average hospital stay was 2.2 days (range 0.5 to 8). At a mean followup of 12 months (range 6 to 24), complications included proctitis in 1.7% of the cases, dysuria in 24%, nocturia in 21% and outlet obstruction in 17%. Erectile function remained unchanged. Prostate volume decreased to 58.9% of the pretreatment value by 12 months and to 44.3% by 24 months. Mean prostate specific antigen level was 18.4 +/- 26.3 ng./ml. before treatment, 3.4 +/- 3.9 ng./ml. at 6 months, 2.3 +/- 2.3 ng./ml. at 12 months and 4.9 +/- 6.0 ng./ml. at 24 months (1.2 +/- 1.0 ng./ml. for patients with no evidence of disease). Of the patients 15.8% had local failure at 18 to 24 months as determined by positive transrectal ultrasound guided biopsy. Five of 58 patients (8.6%) had persistently elevated prostate specific antigen levels, only 1 of whom had a positive biopsy. Laparoscopic pelvic lymph node dissection with transrectal ultrasound guided implantation is a safe and promising mode of therapy for patients with localized prostate cancer.