Peter Langenstroer

Diabetic-induced endothelial dysfunction in rat aorta: role of hydroxyl radicals

OBJECTIVE Previous studies suggest a role of superoxide anion radicals (.O2-) in impaired endothelium-dependent relaxation of diabetic blood vessels; however, the role of secondary reactive oxygen species remains unclear. In the present study, we investigated a role of various potential reactive oxygen species in diabetic endothelial dysfunction. METHODS Thoracic aortic rings from 8-week streptozotocin-induced diabetic and age-matched control rats were mounted in isolated tissue baths. Endothelium-dependent relaxation to acetylcholine (ACH) and endothelium-independent relaxation to nitroglycerin (NTG) were assessed in precontracted rings. RESULTS ACH-induced relaxation was impaired in diabetic compared to control rings and was not improved with either indomethacin or daltroban. ACH-induced relaxation in both control and diabetic rings was completely blocked with the nitric oxide synthase inhibitors, L-nitroarginine methyl ester or L-nitroarginine (L-NA). NTG-induced relaxation was insensitive to L-NA and was unaltered by diabetes. Pretreatment with superoxide dismutase (SOD) at activities which did not alter contractile tone failed to alter response to ACH in diabetic rings. Similar results were obtained using either catalase or mannitol. In contrast, the combination of SOD plus catalase or DETAPAC, an inhibitor of metal-facilitated hydroxyl radical (.OH) formation, markedly enhanced relaxation to ACH in diabetic but not in control rings. Neither the combination of SOD plus catalase nor DETAPAC altered the sensitivity or relaxation to NTG in control rings with or without endothelium. In diabetic rings with endothelium, both DETAPAC or SOD plus catalase increased sensitivity but not maximum relaxation to NTG. In diabetic rings without endothelium, relaxation and sensitivity to NTG were unaltered by either treatment. In L-NA-treated diabetic rings with endothelium, sensitivity and relaxation to NTG was unaltered by either DETAPAC or SOD plus catalase. CONCLUSION Diabetic endothelium produces increases in both .O2- and H2O2 leading to enhanced intracellular production of .OH. Thus, .OH are implicated in diabetes-induced endothelial dysfunction.

Endothelin-1 in the Human Prostate: Tissue Levels, Source of Production and Isometric Tension Studies

Endothelins mediate contractile responses in many types of vascular and nonvascular smooth muscle. The present study represents the first detailed characterization of endothelins in the human prostate. The objectives of this study were to determine the tissue levels and source of endogenous endothelin-1 (ET1) in the human prostate. The contractile effects of ET1 were also investigated using in vitro isometric tension studies. The mean tissue level of ET1 was 0.58 +/- 0.08 pg./mg. tissue wet weight. Endothelin-like activity was markedly prominent in the glandular epithelium of the human prostate, whereas minimal endothelin-like activity was observed in the prostatic stroma. Strips of human prostatic tissue were suspended in isolated tissue chambers and challenged to a concentration response of ET1. The mean EC50 and Emax for ET1 was 3.2 x 10(-8) M. and 0.12 +/- 0.02 gm. force per mm.2 cross-sectional area (CSA), respectively. Preincubation with indomethacin, terazosin, or nifedipine did not alter the concentration-dependent response to ET1. A calcium-free buffer abolished the contractile response to ET1. Thus, ET1 mediates a potent contraction of human prostatic smooth muscle that is not mediated via alpha 1 adrenergic or dihydropyridine sensitive calcium channels or prostaglandin synthesis. The presence of marked endothelin-like immunoreactivity strongly suggests a biological significance for endogenous endothelins in the human prostate.

Intermediate Results of Laparoscopic Cryoablation in 59 Patients at the Medical College of Wisconsin

PURPOSE We report our experience with LC for small renal tumors. MATERIALS AND METHODS Patients who underwent LC at our institution between February 2000 and September 2004 were included in the study. A retrospective chart review was done for perioperative and postoperative parameters as well as clinical outcomes. RESULTS A total of 65 LCs were performed in 59 patients during the period reviewed. Overall 81 renal tumors were cryoablated. Median patient age was 62 years. Median tumor size was 2.5 cm. Median operative time was 190 minutes. Median estimated blood loss was 50 ml. Median hospital stay was 2 days. Conversion to open surgery occurred in 2 patients. Nephrectomy for bleeding occurred in 1 patient. Median followup was 26.8 months. Two recurrences were identified after LC. CONCLUSIONS LC is an alterative modality to laparoscopic partial nephrectomy or open partial nephrectomy for small renal tumors. Tumor recurrence rates in the studies published to date are comparable to those of partial nephrectomy, although longer followup is needed.

Hydroxyl radicals mediate injury to endothelium-dependent relaxation in diabetic rat

The purpose of this study was to determine the radical species which mediates the toxic effects of exogenous oxygenderived free radicals on endothelial function of chronic diabetic rat aorta. Endothelium-dependent relaxation to acetylcholine was impaired in diabetic vessels. Exposure to the exogenous free radical generating system of xanthine plus xanthine oxidase selectively impaired endothelium-dependent relaxation to acetylcholine in control and diabetic aorta with relaxations essentially abolished in diabetic aorta. The loss of relaxation to acetylcholine in diabetic aorta was prevented or attenuated by pretreatment with catalase, dimethylthiourea or desferrioxamine, but not by mannitol or superoxide dismutase. These results suggest that hydroxyl radicals play an important role in the endothelial injury produced by oxygen-derived free radicals in chronic diabetic rat aorta. Furthermore, the site of the injury is likely due to intracellular generation of hydroxyl radicals.

Laparoscopic Cryoablation for Clinical Stage T1 Renal Masses: Long-term Oncologic Outcomes at the Medical College of Wisconsin

OBJECTIVE To report the long-term oncologic outcomes of laparoscopic cryoablation for clinical stage T1 renal masses at the Medical College of Wisconsin. MATERIALS AND METHODS A retrospective chart review was performed evaluating patients who underwent laparoscopic cryoablation for renal masses at the Medical College of Wisconsin between February 2000 and October 2009. RESULTS A total of 171 renal masses in 144 patients were treated by laparoscopic cryoablation during the study period. After excluding patients with <5 years follow-up and those with >clinical stage I disease, 112 renal masses treated in 92 patients remained for analysis. Mean patient age was 59.6 years (standard deviation [SD], 12.5 years). Mean lesion size was 2.3 cm (SD, 0.94 cm). Mean age adjusted Charlson comorbidity index was 4.55 (SD, 1.69). Mean follow-up was 97.9 months (SD, 24.8 months). Overall survival among all patients was 80.9%. Lesions were biopsy proven to be malignant in 70 patients (76.3%). Of those with biopsy-proven malignancy, there were 6 recurrences, 14 non-cancer-related deaths, and 1 cancer-related death, leading to an overall survival of 77.6%, progression-free survival of 91.0%, and cancer-specific survival of 98.5%. CONCLUSION We report the largest published series of laparoscopic renal cryoablation with the longest follow-up. Our series indicates that laparoscopic cryoablation is both an efficacious treatment for clinical stage T1 renal masses and provides excellent long-term oncologic outcomes.

Initial Experience With Home Therapeutic Electrical Stimulation for Continence in the Myelomeningocele Population

PURPOSE In an attempt to enhance bladder and bowel continence 29 patients underwent long duration, low intensity transcutaneous therapeutic electrical stimulation. This technology has previously been shown to be effective for inducing regenerative hypertrophy of disuse atrophied skeletal muscle, and it has been associated with improved continence in the myelomeningocele population. Our objectives were to enhance urinary and fecal continence, and evaluate the mechanisms by which therapeutic electrical stimulation influences continence. MATERIALS AND METHODS A total of 29 children with lumbar or sacral myelomeningocele underwent therapeutic electrical stimulation at home during sleep using a commercially available stimulator with a safety sensing circuit and 2 sets of electrodes placed on the skin at bedtime. Left and right side electrode placement was alternated on 6 of 7 consecutive nights. In 9 boys and 2 girls with more than 9 months of followup initial and subsequent cystometrography, urethral pressure profile, electromyography, voiding cystourethrography and renal ultrasound studies were evaluated. RESULTS In the 11 children there was no radiographic evidence of urinary tract or musculoskeletal deterioration during treatment. Mean actual bladder capacity increased from 133 to 196 ml. (p < 0.05). Mean bladder capacity, as a percent of maximum predicted bladder capacity for a normal age matched child without myelomeningocele, also significantly increased from 59 before to 76% after 9 months of therapeutic electrical stimulation (p < 0.05). No significant change was noted in urethral pressure profile. A subjective improvement in the sensation of pelvic fullness was also observed. CONCLUSIONS When administered at home by parents while the child sleeps, therapeutic electrical stimulation is safe for bladder and bowel continence in the myelomeningocele population. It seems to increase significantly bladder capacity, does not appear to change urethral pressure profile and results in a subjectively improved sensation of pelvic fullness, enhancing urinary and fecal continence. The most beneficial effect of therapeutic electrical stimulation seems to be on the bladder wall and less so on the striated pelvic floor musculature with subjective enhancement of pelvic fullness also contributing positively.

Resonance® Metallic Ureteral Stents Do Not Successfully Treat Ureteroenteric Strictures

PURPOSE To report the outcomes of patients with ureteroenteric strictures after ileal conduit urinary diversion that were managed with Resonance metallic ureteral stents. PATIENTS AND METHODS Ten ureteroenteric strictures in patients with ileal conduits that were managed with metallic ureteral stenting were retrospectively identified. Charts were examined for patient age, anastomosis type, stricture cause, stricture laterality, complications, and follow-up. RESULTS Nine of 10 (90%) cases resulted in distal stent migration. Mean time to stent migration was 21 days (range 3-60 d). CONCLUSIONS Placement of Resonance metallic stents in patients with ileal conduits is ineffective for management of ureteroenteric strictures because of the high rate of distal migration.

Effects of Short-Term Finasteride on Apoptotic Factors and Androgen Receptors in Prostate Cancer Cells

PURPOSE We explored the molecular correlates of the effect of finasteride on prostate tissue in patients undergoing radical prostatectomy. MATERIALS AND METHODS Patients undergoing radical prostatectomy for localized prostate cancer were eligible for study. After providing informed consent patients were randomized to receive 5 mg finasteride or placebo daily for at least 30 days before surgery. At surgery prostate tissue was harvested from the surgical specimen and sent for analysis. Tissue samples were analyzed for the pro-apoptotic factors caspase-3, caspase-7 and IGFBP-3. Samples were also analyzed for the tumor suppressor/proto-oncoproteins bcl-2, p53 and p21. Finally, tissues were analyzed for androgen receptor density and insulin growth factor-1. RESULTS A total of 22 study and 20 placebo samples were collected and analyzed. Negligible staining for bcl-2 or caspase-3 was noted in each group. Statistical differences were not observed for bcl-2, p53, p21 or insulin growth factor-1 between the groups. There was a statistically significant difference in caspase-7 and IGFBP-3. A mean of 77% and 99.9% of cells stained for caspase-7 in the treatment and placebo groups, respectively (p = 0.007). In 3 patients caspase-7 staining disappeared completely and it was decreased by 70% and 50% in 1 patient each. Mean intensity staining for IGFBP-3 was 1.03 in the treatment group and 1.54 in the placebo group (p = 0.005). The staining intensity of nuclear androgen receptors on benign and cancerous cells was not significantly different between the treatment and placebo groups. However, there was a significant difference in androgen receptor staining between benign and cancer cells in the 2 populations. Mean nuclear androgen receptor staining intensity in all cancer and all benign tissue samples was 119.3 and 151.8, respectively (0.001). CONCLUSIONS Finasteride administered 30 days before surgery appears to decrease the apoptotic factors caspase-7 and IGFBP-3 in cancer cells, while having little to no effect on caspase-3, insulin growth factor-1, bcl-2, p53 and p21. This short-term study may have interesting implications for interpreting Prostate Cancer Prevention Trial data on the molecular level. No differences were noted between the treatment and placebo groups in the expression of nuclear androgen receptor. However, decreased expression of androgen receptors was present in cancer cells compared to that in benign prostate cells in the 2 groups.

Bacille-Calmette Guèrin induces caspase-independent cell death in urothelial carcinoma cells together with release of the necrosis-associated chemokine high molecular group box protein 1.

To evaluate the ability of bacille‐Calmette Guèrin (BCG) to induce caspase‐independent cell death and release the necrosis‐associated chemokine high molecular group box protein 1 (HMGB1) from urothelial carcinoma (UC) cells; a correlative clinical trial determined if BCG treatment resulted in increased urinary levels of HMGB1.

Abuse of guaifenesin-containing medications generates an excess of a carboxylate salt of beta-(2-methoxyphenoxy)-lactic acid, a guaifenesin metabolite, and results in urolithiasis

OBJECTIVES Several urinary calculi were submitted to our institution for compositional analysis. The typical techniques of analysis, polarized light microscopy, electron microprobe analysis, and infrared spectroscopy proved inadequate for a definitive identification. As a result, a more detailed organic analysis was conducted to determine the exact chemical structure of the material. METHODS Infrared spectroscopy and mass spectrometric analysis were carried out on the solid material, providing information concerning the functional groups and the molecular mass of the organic constituent and its components. The stone was solubilized in deuterated solvents and analyzed by nuclear magnetic resonance spectroscopy, which resulted in a definitive chemical structure. RESULTS The spectroscopic analysis indicated that the stones were composed of a calcium salt of beta-(2-methoxyphenoxy)-lactic acid, a metabolite of the pharmaceutical guaifenesin, which is used as an expectorant. CONCLUSIONS Guaifenesin, an expectorant common in over-the-counter cold and allergy remedies, can cause urolithiasis if taken in excess. Discussions with physicians and their patients confirmed that most patients admitted to taking large doses of guaifenesin-containing medications.