Faculty Bibliography

BACKGROUND: Endothelin-1 (ET-1) interacts with specific G-protein-coupled receptors to initiate short-term (contraction) and long-term (mitogenesis) events in target cells. ET-1 is an abundant prostate secretory protein that, in its biologically active form, elicits prostatic smooth muscle contraction. The present study was designed to determine the effects of ET-1 on prostate cell growth and to examine the regulation of endogenous ET-1 activity and bioavailability. METHODS: Primary cultures of prostate secretory epithelial (PE) and prostate fibromuscular stromal (PS) cells were established from benign human prostate tissue. RESULTS: In culture, PE cells secrete immunoreactive ET-1 (38.5 +/- 1.6 pg/ml/10(6) cells/24 hr) into the conditioned medium. Levels of immunoreactive ET-1 produced by PS cells were more than 10-fold lower. Endothelin-converting enzyme-1 (ECE-1) mRNA was detected in PE cells and not in PS cells; however, big ET-1 was the predominant immunoreactive ET-1 secretory product of PE cells. The ET(B) endothelin receptor was the predominant subtype in both PE and PS cells. In PS cells, but not PE cells, ET-1 induced significant inositol phosphate accumulation and [3H]-thymidine uptake. Agonist activity was inhibited by the ET(B) receptor selective antagonist, BQ 788. Intact PE cell monolayers secrete ET-1 through the apical surface, consistent with secretion of ET-1 into the glandular lumen in vivo. CONCLUSIONS: On the basis of these findings, regulation of ET-1 activity and bioavailability appears to be tightly regulated. Such findings have important implications in the pathophysiology of prostate disease

Despite the well-characterized histology associated with benign prostatic hyperplasia, very little is known about the underlying etiology of the disease on a molecular basis. The objective of this study was to use the technique of mRNA differential display in order to identify genes differentially expressed in human transition zone prostate tissue with high stromal density, with high epithelial density, and with nonhyperplastic histology. The extracellular matrix chondroitin/dermatan sulfate proteoglycan (CDSP) mRNA was more abundantly expressed in tissue with high stromal density, consistent with earlier findings that dermatan and chondroitin 6-sulfate glycosaminoglycans are increased in hyperplastic prostates. Messenger RNA encoding the negative regulator of cell cycle progression, BTG2, was more abundantly expressed in tissue with high epithelial densities. CDSP mRNA was abundantly expressed in primary cultures of stromal cells but was undetectable in epithelial cells. BTG2 mRNA was expressed in primary cultures of both cell types, but more abundantly in epithelial cells. BTG2 mRNA, but not CDSP mRNA, was subject to significant growth cycle regulation in cultured stromal and epithelial cells, with maximum expression occurring in quiescent cells. Generation of specific antibodies to BTG2 revealed that this protein was expressed at low levels in stroma, nonhyperplastic glands, and in hyperplastic glands. Consistent with a role in cell-cycle regulation, BTG2 protein was abundantly expressed in atrophic glands and preatrophic glands.

PURPOSE: The aim of this study was to determine the expression and localization of the P2Y1 purinoceptor mRNA in rat penis and urinary bladder using reverse transcription polymerase chain reaction (RT-PCR), northern blotting and in situ hybridization (ISH). MATERIALS AND METHODS: RT-PCR: First strand cDNA was prepared from rat penis and urinary bladder dome total RNA and used for PCR with primers designed to amplify fragments of the P2Y1 purinoceptor cDNA sequence. Northern blotting: PCR products were subcloned into the pGEM-5Zf(+) plasmid vector, sequenced and random primer labeled using 32p. Labeled probe was hybridized. ISH: Digoxigenin labeled cRNA probes were synthesized by in vitro transcription. RESULTS: P2Y1 purinoceptor mRNA was detected by RT-PCR analysis in both rat penis and urinary bladder. RNA blotting using a P2Y1 purinoceptor cDNA probe revealed a single transcript of 4.2kb in both tissues. This band was the same size as that expressed by the heart, which contains high levels of P2Y1 purinoceptor (Burnstock, G.: Physiological and pathological roles of purines: an update. Drug. Dev. Res., 28: 195, 1993). By ISH, P2Y1 purinoceptor mRNA was localized in detrusor smooth muscle cells and blood vessels in urinary bladder. In penis, positive signals were detected in endothelial cells which line the lacunar space and blood vessels. No hybridization was seen in corpus cavernosum smooth muscle cells and urethra. CONCLUSION: These results indicate that mRNAs for P2Y1 purinoceptor are expressed in detrusor smooth muscle cells and blood vessels of rat urinary bladder. However, in penis, this receptor is expressed in endothelial cells which lines the lacunar space and blood vessels, but not expressed in corpus cavernosum smooth muscle cells and urethra

PURPOSE: Radical retropubic prostatectomy is often performed with preservation of the bladder neck. We examine the incidence of benign and malignant prostatic tissue at the bladder neck margin in men undergoing radical retropubic prostatectomy with preservation of the bladder neck for clinically localized prostate cancer. MATERIALS AND METHODS: The study included 100 cases of radical retropubic prostatectomy with preservation of the bladder neck performed by a single surgeon (H. L.). A 2 mm. thick circumferential specimen was excised from the bladder neck, divided into 4 quadrants (anterior, posterior, right and left) and submitted for frozen section examination. The permanent sections from these bladder neck biopsies and the entire surgical specimens were analyzed by a single pathologist (J. M.). RESULTS: The frozen section diagnosis from the bladder neck biopsies were adenocarcinoma, benign prostatic tissue and no prostatic tissue in 3, 38 and 59 cases, respectively. The permanent section diagnosis of the bladder neck biopsies was adenocarcinoma, benign prostatic tissue and no prostatic tissue in 4, 57 and 39 cases, respectively. The sensitivity specificity, and positive and negative predictive values for examination of the surgical specimen to identify benign prostatic tissue was 67, 90, 90 and 65%, respectively. The bladder neck was re-biopsied because of the findings of adenocarcinoma and benign prostatic tissue in 3 and 8 cases, respectively. The initial bladder neck biopsy resulted in pathological down staging to pT2c in only 1 case. Repeat resection of the bladder neck in all cases with 10% or less benign prostatic tissue showed no prostatic tissue, whereas 50% of the cases with more than 10% benign prostatic tissue demonstrated residual benign prostatic tissue. Serum prostate specific antigen was undetectable immediately after radical retropubic prostatectomy in all cases with benign prostatic tissue only. CONCLUSIONS: Preservation of the bladder neck during radical retropubic prostatectomy does not significantly compromise total extirpation of the malignant process. Benign prostatic tissue at the bladder neck margin is relatively common. Examination of the surgical specimen has limited sensitivity, and negative and positive predictive values for the presence of benign prostatic tissue at the bladder neck margin. The impact of benign prostatic tissue as it relates to future malignant transformation is unknown. Submitting frozen section specimens from the bladder neck is reasonable for the younger man who may be at risk from benign prostatic tissue at the bladder neck margin

PURPOSE: We determine whether smooth and skeletal muscle or nerve density is altered in the lower genitourinary or gastrointestinal tract of male human fetuses with myelomeningocele at 20 weeks of gestation. MATERIALS AND METHODS: We serially cross sectioned the lower genitourinary and gastrointestinal tracts in 7 male fetuses (mean age 20 weeks of gestation) with myelomeningocele and 4 age matched controls. Immunohistochemical staining was performed using Masson's trichrome stain and antibodies to smooth and skeletal muscle actin. S-100 protein staining for Schwann cell localization and neurofilament protein was also done. Fluorescein and rhodamine double immunolabeling was used to demonstrate the co-expression of smooth and skeletal muscle. RESULTS: Peripheral neural innervation of the bladder, prostate and rectum was markedly decreased in myelomeningocele. Masson's trichrome and smooth muscle actin staining also demonstrated that smooth muscle was less well differentiated in myelomeningocele specimens. Scant smooth muscle was present in the myelomeningocele bladder and bladder neck with an excess of collagen in an interfascicular and intrafascicular distribution. Double immunofluorescence staining revealed persistent co-expression of smooth and skeletal muscle actin by myocytes in the myelomeningocele detrusor, while in the control bladder there was only smooth muscle expression. The skeletal muscle component of structures in fetuses with myelomeningocele, including the external sphincter, was similar to that in controls. Prostatic size, ductal morphogenesis and smooth muscle were decreased compared to those in controls. CONCLUSIONS: A global defect exists in the development of smooth muscle in myelomeningocele in the lower genitourinary and gastrointestinal tracts by 20 weeks of gestation. Peripheral nerve density is decreased in smooth muscle in myelomeningocele, suggesting that an intact nervous system is important for the development of normal smooth muscle. Fetal surgery with coverage of the spinal cord in select cases may prevent progressive environmental injury to the somatic nervous system during the second half of gestation. However, achieving normal autonomic function is unlikely due to the extent of early global organ maldevelopment

OBJECTIVES: To evaluate the long-term efficacy and safety of once-daily tamsulosin (0.4 and 0.8 mg), a unique selective alpha1A-adrenoceptor antagonist in patients with benign prostatic hyperplasia (BPH). METHODS: This trial extended a 13-week, Phase III multicenter placebo-controlled, double-blind outpatient trial for an additional 40 weeks. Of 618 patients, 418 (68%) continued into the extension phase on the same double-blind medication and dose. The primary efficacy parameters were total American Urological Association (AUA) symptom score and maximum urinary flow (Qmax). RESULTS: The mean changes in AUA symptom score from baseline to end point were statistically significant in all groups (P <0.001). Significant improvements were observed in Qmax for both tamsulosin groups but not for the placebo group. The statistically significant improvements from baseline in efficacy parameters observed for each tamsulosin group at the end of the 13-week Phase III trial were maintained during the long-term extension phase. Tamsulosin at both dosages was well tolerated as maintenance therapy. Clinically significant orthostatic hypotension was not observed. Vital sign changes in either hypertensive or normotensive patients were not clinically significantly different across the three groups. CONCLUSIONS: Tamsulosin once-daily at 0.4 or 0.8 mg was shown to be effective, safe, and well tolerated in the target BPH population during long-term use

OBJECTIVES: To evaluate the efficacy and safety of two once-daily doses of tamsulosin, the first selective alpha1A-antagonist studied in clinical trials. METHODS: Patients with benign prostatic hyperplasia (BPH) were randomized to receive either tamsulosin (0.4 and 0.8 mg/day) or placebo (n = 756). Primary efficacy parameters were improvement in the total American Urological Association (AUA) symptom score and peak urinary flow (Qmax). Secondary efficacy parameters were improvement in measurements at individual double-blind visits corresponding to the primary efficacy parameters; percentage of patients with a 3-mL/s increase in Qmax; total AUA irritative, obstructive, and bother scores; individual AUA symptom scores; total, irritative, obstructive, and individual Boyarsky symptom scores; average urinary flow rate and other uroflowmetric parameters; and investigator's global assessment. RESULTS: Statistically significant improvements in all efficacy parameters were observed in tamsulosin-treated compared with placebo-treated patients. Additionally, the 0.4-mg/day dose demonstrated a rapid onset of action (4 to 8 hours) based on Qmax after the first dose of double-blind medication. A review of the safety parameters demonstrated excellent tolerance at 1 week after the initial 0.4-mg/day dose and continued tolerance during the additional 12 weeks of 0.4- and 0.8-mg/day dosing. The incidence of positive orthostatic test results in the tamsulosin groups was comparable to that observed in the placebo group. Adverse events were comparable in the 0.4-mg/day tamsulosin and placebo groups and were somewhat higher in the 0.8-mg/day tamsulosin group. CONCLUSIONS: Tamsulosin was effective, safe, and well tolerated in the target BPH population at both the 0.4- and 0.8-mg/day dose levels, without the blood pressure-lowering effects typical of nonselective alpha-adrenergic antagonists