Primary mucinous adenocarcinoma of the urethra: A contemporary clinicopathologic analysis of 17 patients

Mucinous adenocarcinoma of the urethra is rare. Here we performed a contemporary clinicopathologic analysis of this entity in both male and female patients. All cases with secondary tumors involving the urethra were excluded. Clinicopathologic parameters and follow up was obtained. Seventeen patients were included in the study, 9/17 (53 %) male and 8/17 (47 %) female. The mean patient age was 68 years (range: 53-88 years). The majority (11/17, 65 %) of patients were African American, with an even greater incidence (7/8, 87 %) in female patients. In male patients, prostatic urethra was the most common part of the urethra (6/9, 67 %) where the tumor arose from. Immunohistochemical stains were performed in 11/17 (65 %) tumors and were positive for CK20 (11/11, 100 %), CDX2 (11/12, 92 %), CK7 (8/9, 88 %), GATA3 (3/8, 37 %) and negative for NKX3.1, PSA, p63, PAX8, and Beta-Catenin. In resection specimens, tumors were categorized as pT2 (3/11, 27 %), pT3 (1/11, 9 %), and pT4 (7/11, 64 %). Lymph node status was categorized as pN0 (6/9, 67 %), pN1 (1/9, 11 %), and pN2 (2/9, 22 %). Available follow up data showed 7/13 (54 %) patients developed recurrence after surgical resection and chemotherapy, of which 3/7 (43 %) died of widespread metastatic disease. It is critical for pathologists and urologic oncologists to be aware of this entity in both male and female patients in view of potential diagnostic pitfalls, prognosis, and therapeutic implications.

Primary mucinous adenocarcinoma of the urethra: A clinicopathological analysis of 35 cases

AIM

Primary mucinous adenocarcinoma of the urethra represents an extremely rare entity. We sought to characterise further these tumours' clinicopathological, immunohistochemical and molecular features.

METHODS AND RESULTS

Thirty-five cases were identified, occurring in 18 males and 17 females. The mean age at diagnosis was 65 years (28-89 years). The main presentation symptoms were haematuria and urinary outlet obstruction. Microscopic analysis revealed that all 35 tumours have stromal dissection by mucin. Ten tumours showed villoglandular dysplasia, nine showed mucinous metaplasia, two showed adenocarcinoma in situ and four showed signet ring cell features. All tumours were immunopositive for CEA, while immunonegative for nuclear β-catenin; 19 of 23 (83%) expressed high molecular weight cytokeratin; 19 of 33 (58%) CK7; 28 of 34 (82%) CK20; 32 of 35 (91%) CDX2; 22 of 27 (81%) cadherin-17 (CDH-17); 26 of 29 (90%) SATB2; and one of 31 (3%) GATA3. Mismatch repair gene products, including MLH1, PMS2, MSH2 and MSH6, were immunopositive, suggesting the MSI-low genotype of mucinous adenocarcinoma of the urethra. BRAF V600E and ALK rearrangements were not detected. During the mean follow-up of 20 months, nine patients either developed distant metastasis or succumbed to the illness.

CONCLUSION

Our study, encompassing the most extensive series of 35 cases of primary mucinous adenocarcinoma of the urethra, provides crucial insights into its precise diagnosis, management and potential targeted treatments. We found a greater CDX2, SATB2 and CDH17 sensitivity in these urethral tumours for the first time, to our knowledge. We identified characteristics such as an MSI-low profile, non-V600E BRAF mutations and an absence of ALK rearrangements.

[Effects of delivery and oophorectomy on urethral collagen: an experimental study]

OBJECTIVE

Stereological evaluation of the concentration of type I and III collagen fibers in the urethral tissue of rats subjected to simulated labor and oophorectomy. To compare the concentrations of collagen between oophorectomized and non-oophorectomized rats.

MATERIAL AND METHOD

Sixty adult Wistar rats were divided into six groups. A group made up of virgin rats was used as control group and another group was made up of oophorectomized rats. Two groups underwent vaginal distention for 30 and 120 minutes, respectively. The two other groups were subjected to the same distension periods, followed by oophorectomy. Sixty days later, euthanasia and removal of urethral tissue was carried out for stereological analysis of type I and III collagen after staining with hematoxylin and eosin and picrosirius red.

RESULTS

A decrease in estrogen levels was observed in the oophorectomized rats. There was a reduction of type III collagen in the oophorectomized control group compared to the control group when analyzed independently. No significant differences were observed among the other groups. Type I collagen decreased in all groups compared to the control group. However, in the prolonged vaginal distension and oophorectomy group, these fibers increased.

CONCLUSION

In normal rats, simulation of labor does not alter the collagen III levels. In hypoestrogenic rats, the concentration of collagen type I and III decreased, except in those undergoing prolonged labor simulation in which collagen I increased.

Expression of pleiotrophin in the prostate is androgen regulated and it functions as an autocrine regulator of mesenchyme and cancer associated fibroblasts and as a paracrine regulator of epithelia

BACKGROUND

Androgens and paracrine signaling from mesenchyme/stroma regulate development and disease of the prostate, and gene profiling studies of inductive prostate mesenchyme have identified candidate molecules such as pleiotrophin (Ptn).

METHODS

Ptn transcripts and protein were localized by in situ and immunohistochemistry and Ptn mRNA was quantitated by Northern blot and qRT-PCR. Ptn function was examined by addition of hPTN protein to rat ventral prostate organ cultures, primary human fetal prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia.

RESULTS

During development, Ptn transcripts and protein were expressed in ventral mesenchymal pad (VMP) and prostatic mesenchyme. Ptn was localized to mesenchyme surrounding ductal epithelial tips undergoing branching morphogenesis, and was located on the surface of epithelia. hPTN protein stimulated branching morphogenesis and stromal and epithelial proliferation, when added to rat VP cultures, and also stimulated growth of fetal human prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia. PTN mRNA was enriched in patient-matched normal prostate fibroblasts versus prostate cancer associated fibroblasts. PTN also showed male enriched expression in fetal human male urethra versus female, and between wt male and ARKO male mice. Transcripts for PTN were upregulated by testosterone in fetal human prostate fibroblasts and organ cultures of female rat VMP. Ptn protein was increased by testosterone in organ cultures of female rat VMP and in rat male urethra compared to female.

CONCLUSIONS

Our data suggest that in the prostate Ptn functions as a regulator of both mesenchymal and epithelial proliferation, and that androgens regulate Ptn levels.

[Clinical observation on therapeutic effect of electroacupuncture on chronic prostatitis and detection of urethral sphincter EMG]

OBJECTIVE

To observe the clinical therapeutic effect of electroacupuncture for chronic prostatitis and investigate its mechanism.

METHODS

Forty-eight cases were randomly divided into an electroacupuncture group and a western medicine group, 24 cases in each group. The electroacupuncture group was treated by electroacupuncture and Guanyuan (CV 4), Zhongji (CV 3). Ciliao (BL 32) and Huiyang (BL 35) were selected as main acupoints. The western medicine group was treated by oral administration of Sparfloxacin tablets and Prostat tablets. The scores of NIH-CPSI, changes in uroflow rate-urethral sphincter EMG and their therapeutic effects were observed.

RESULTS

The total effective rate was 87.5 % in the electroacupuncture group which, was better than 62. 5% in the western medicine group (P(<0. 05). There were significant differences in the scores of NIH-CPSI and Q(max), Q(ave), TL value before and after treatment in the electroacupuncture group (all P<0.05), and with a significant difference in the scores of NIH-CPSI and Q(max). Q(ave), TL value after treatment between the two groups (all P<0.05).

CONCLUSION

Electroacupuncture based on syndrome differentiation has better therapeutic effect on chronic prostatitis than that of routine clinical medicine.

Immunohistochemical localization of androgen receptors in the urogenital tracts of human embryos

The aim of this study was to investigate androgen receptor (AR) expression in the developing human urogenital tract. The distribution of AR was examined in paraffin-embedded tissue sections of the lower urogenital tract using 55 human embryos of 8-12 weeks of gestation. Immunohistochemistry was performed for AR detection and gender was determined by polymerized chain reaction. There were no differences in the distribution of AR in male and female embryos at any stage of gestation. AR was present only in the mesenchymal tissues of the urogenital sinus at 8 weeks whilst the epithelium was negative, but after 9 weeks the epithelium also showed progressively more positive staining. In the phallus, AR staining was prominent. There was far less staining in the epithelium of the urethral groove from 8 to 10 weeks, whilst the mesenchyme of the urethral folds showed positive staining. At 11 and 12 weeks, both the urethral groove and folds showed uniform staining. The genital tubercle, genital swelling and bulbourethral gland precusors were also positively stained, although paramesonephric ducts were negative. Staining was observed in the mesonephric duct from 9 weeks. There was an absence of staining in the rectum at all stages of gestation. The expression of AR in an epithelium may be dependent upon the mesenchyme. Mesenchymal-epithelial interactions played an important role in development, as has been described in experimental animals. AR expression could play a part in the growth of the genital organs.

The effect of labor and/or ovariectomy on rodent continence mechanism--the neuronal changes

Many women develop stress urinary incontinence (SUI) after childbirth, but the exact neuronal changes are largely unknown. This study is designed to identify the neuronal changes associated with pregnancy, delivery and ovariectomy. A total of 10 virgin and 48 pregnant rats were used. Cystometry and stress/sneeze tests were performed in the virgin once and the pregnant rats at certain time points. Postpartum the rats were equally grouped as follows: group I: delivery, group II: delivery + ballooning, group III: delivery + ovariectomy, group IV: delivery + ballooning + ovariectomy. Tissues from bladder, bladder neck, and urethra were analyzed by immunostaining for PGP 9.5, CGRP, SP, NPY, VIP, TH, n-NOS. We found complex innervation changes in the different tissue samples. Since the bladder neck and the mid-urethra play an important role in the continence mechanism the neuronal changes in these areas contribute to the observed functional changes.

Location of bladder and urethral sphincter motoneurons in the male guinea pig (Cavia porcellus)

Although the guinea pig is used widely in experimental medical research, including in studies on micturition control, the spinal origin of preganglionic parasympathetic bladder and somatic external urethral sphincter motoneurons is not known. In the male guinea pig using wheat germ agglutinin-conjugated horseradish peroxidase and dextran Alexa Fluor 488/568 tracers, preganglionic parasympathetic bladder motoneurons were observed in the ventrolateral part of the intermediolateral cell group of the first sacral segment. The external urethral sphincter motoneurons were found to be located in the ventral horn of the first sacral segment, in a cell group corresponding with the nucleus of Onuf in cat and human.

An experimental model for stricture studies in the anterior urethra of the male rabbit

In this study, an animal model was developed for the examination of urethral strictures (US). Through a resectoscope, a resection was made in the urethras of 15 male rabbits. After 30 days, the rabbits were evaluated with urethrography, impedance planimetry and either histology or the determination of collagen content. Fifteen rabbits serving as controls were evaluated in the same way. Three rabbits in the resection group and one in the control group died before evaluation. Urethrography demonstrated a stricture in the remaining 12 animals in the resection group. The urethras of the control animals were all normal. Impedance planimetry confirmed that the luminal cross sectional area (CSA) of the strictures was significantly smaller than the CSA of the corresponding part of the urethra in the control group. No difference in CSA was found 1 cm proximal to the stricture. The strictures consisted of densely woven collagen which sent tongues into the adjacent normal parts of the urethra. No difference in collagen content was found between the two groups either at the stricture site or 1 cm proximally. The described method of producing US in the rabbit model was very consistent with all operated animals developing a stricture. The model might prove valuable in evaluating new methods for the treatment of US.

Menstrual phase-dependent gene expression differences in periurethral vaginal tissue from women with stress incontinence

OBJECTIVE

The mechanical stability of the genitourinary tract is dependent on intact collagen fibers that support the bladder neck, urethra, and pelvic organs. We hypothesize that genetic differences in collagen metabolism may contribute to stress urinary incontinence. Because sex hormones have substantial influence on the female lower urinary tract throughout adult life, we investigated the gene expression of vaginal tissue of women with stress incontinence compared with women with no stress incontinence in the proliferative phase of the menstrual cycle.

STUDY DESIGN

Quantitative competitive polymerase chain reaction was used to verify that the gene expressions were similar between periurethral vaginal tissue and pelvic ligamentous tissue. Labeled complementary RNA was obtained from periurethral vaginal tissue in five pairs of age- and menstrual phase-matched, premenopausal women with and without stress urinary incontinence. The vaginal tissues were then hybridized on HuGeneFL arrays that contained probes representing 6800 full-length human genes. The Student t test and Mann-Whitney ranking were used independently to select candidates with probability values <.05. Hierarchical clustering analysis was performed on the selected candidates to assess the ability of these genes to discriminate between normal and affected individuals.

RESULTS

Tissue inhibitor of metalloproteinases-1 and estrogen receptor-alpha messenger RNA expressions were found to be similar between uterosacral ligament and periurethral vaginal tissue in six participants. Of the 90 candidate genes that were identified, 62 genes were up-regulated and 28 were down-regulated in the stress urinary incontinence group. Genes that were involved in extracellular matrix activity in the up-regulated group include transforming growth factor-beta3, laminin, and collagen type VI. Down-regulated genes that may participate in collagen metabolism include laminin-related protein, collagen XVII, serine/threonine protein kinase, type II interleukin-1 receptor, and platelet-derived growth factor-associated protein.

CONCLUSION

In this preliminary study, we identified differential gene expressions that may contribute to extracellular matrix remodeling in pelvic tissue from women with stress urinary incontinence in the proliferative phase versus continent control subjects. The alteration in expression of these candidate genes suggests that they should be targets for further investigation.

Analysis of feline urinary calculi and urethral plugs by infrared spectroscopy and scanning electron microscopy

The chemical constituents of 34 feline urinary calculi and five urethral plugs were analysed by infrared spectroscopy. The analysis revealed that 18 (52.9 per cent) of the calculi contained magnesium ammonium phosphate hexahydrate (struvite) as the major component; 10 (29.4 per cent) contained complex ammonium urates (three of them also containing calcium phosphate, mainly on the surface); three were composed of calcium phosphates and three were composed mainly of calcium oxalate mono and dihydrates. The urethral plugs were composed primarily of struvite, but also contained large amounts of organic matter. The examination of 16 selected samples by scanning electron microscopy and electron dispersive x-ray analysis revealed that their crystalline structures were similar to those of canine stones.

Histological and electrical properties of rat dorsal root ganglion neurons innervating the lower urinary tract

We investigated whether primary afferent neurons innervating different regions of the lower urinary tract have different histochemical and electrophysiological properties. Neurons in rat L6-S1 DRG were identified by axonal transport of a fluorescent dye. Neurofilament-negative C-fiber cells comprise approximately 70% of bladder and proximal urethral afferent neurons that send axons through the pelvic nerves, but comprise a smaller proportion (51%) of distal urethral neurons that send axons through the pudendal nerves. Isolectin-B4 (IB4) binding was detected in a higher percentage (49%) of C-fiber neurons innervating the distal urethra than in those innervating the bladder or proximal urethra (18-22%). Neurofilament-positive A-fiber neurons innervating the distal urethra had a larger average somal size than neurons innervating the bladder or proximal urethra. In patch-clamp recordings, the majority (70%) of bladder and proximal urethral neurons were sensitive to capsaicin and exhibited TTX-resistant, high-threshold action potentials, whereas a smaller proportion (53%) of distal urethral neurons exhibited TTX-resistant spikes. T-type Ca2+ currents were observed in 47% of distal urethral neurons with TTX-sensitive spikes, but not in TTX-sensitive bladder or proximal urethral neurons. In summary, afferent neurons innervating bladder or proximal urethra differ from those innervating distal urethra. The latter, which more closely resemble cutaneous afferent neurons, consist of a smaller number of C-fiber neurons containing a higher percentage of IB4-positive cells and a more diverse population of A-fiber neurons, some of which exhibit T-type Ca2+ channels. These differences may be related to different functions of respective target organs in the lower urinary tract.

Nitric oxide synthase in the external urethral sphincter of the sheep: immunohistochemical and functional study

PURPOSE

We studied the distribution of neuronal nitric oxide synthase (nNOS) and the effects of nitric oxide (NO) modulating drugs on contractile function of the external urethral sphincter of lambs. Gender differences were evaluated.

MATERIALS AND METHODS

Longitudinal and transverse sections of the external urethral sphincter from 10 female and 10 male lambs were studied using reduced nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry and nNOS immunocytochemistry. Isometric contractile responses to electrical field stimulation were recorded from external urethral sphincter preparations from 47 female and 45 male lambs and the effects of NO modulating drugs were evaluated.

RESULTS

We detected nNOS in the sarcolemma of some but not all striated fibers, where nNOS seems to be concentrated at the neuromuscular junction. In addition, nNOS was present in nerve fibers and intramural ganglia. The density of innervation decreased toward the distal part of the external urethral sphincter and was higher in male preparations. No significant functional effects of the NOS inhibitor NG-nitro-L-arginine (10 mM.) or the NO donors diethylamine and spermine NONOate (Sigma Chemical Co., St. Louis, Missouri) (5 mM. each) on external urethral sphincter isometric contractility were found in either gender.

CONCLUSIONS

Despite the evidence for nNOS at the sarcolemma and nerve fibers of the external urethral sphincter the physiological relevance of these immunohistochemical findings remains to be determined.

[Pharmacological analysis of neurotransmitters contributing to lower urinary tract function]

Lower urinary tract function is controlled by the autonomic nervous system, which consists of adrenergic, cholinergic, and non-adrenergic, non-cholinergic (NANC) neurons. We have measured the amount of various neurotransmitters (acetylcholine, ACh; noradrenaline, NA; adenosine triphosphate, ATP; and nitric oxide, NO) released from human and rabbit urinary tract smooth muscles by the microdialysis method coupled with HPLC. Muscle strips are isolated from human or rabbit bladder, urethra, and prostate. A microdialysis probe was inserted into each smooth muscle strip. Each muscle strip was connected to an isometric transducer, and tension development was measured. We have evaluated the changes in electrical field stimulation-induced neurotransmitter releases and functional responses in physiological and pathological conditions and the interactions between neurotransmitters or neurons. In this review, we present several of our results: 1) interactions between adrenergic and nitrergic neurons in rabbit urethra, 2) effect of NO on human bladder function, 3) effect of NO on human prostate function, and 4) effects of aging on acetylcholine and ATP releases from human bladder smooth muscles. These data may reveal physiological or pathological neurotransmitter control of lower urinary tract function and give us useful information for clinical intervention to treat lower urinary tract symptoms.

Androgens and the development of the vagina

Today it is generally held that the vagina develops from sinovaginal bulbs and that the lower third of the definitive vagina is derived from the urogenital sinus. Here we show that the entire vagina arises by downward growth of Wolffian and Müllerian ducts, that the sinovaginal bulbs are in fact the caudal ends of the Wolffian ducts, and that vaginal development is under negative control of androgens. We designed a genetic experiment in which the androgen receptor defect in the Tfm mouse was used to examine the effects of androgens. Vaginal development was studied by 3D reconstruction in androgen-treated female embryos and in complete androgen-insensitive littermates. In androgen-treated females, descent of the genital ducts was inhibited, and a vagina formed in androgen-insensitive Tfm embryos as it does in normal females. By immmunohistochemical localization of the androgen receptor in normal mouse embryos, we demonstrated that the androgen receptor was expressed in Wolffian duct and urogenital sinus-derived structures, and was entirely absent in the Müllerian duct derivatives. We conclude that the Wolffian ducts are instrumental in conveying the negative control by androgens on vaginal development. The results are discussed under evolutionary aspects at the transition from marsupial to eutherian mammals.

Evidence for a potential role of estrogen in the penis: detection of estrogen receptor-alpha and -beta messenger ribonucleic acid and protein

Body tissues are traditionally classified as estrogen targets based on both the response to the hormone and the presence of estrogen receptors (ERs). We undertook the study on expression of ERalpha and ERbeta in the penis to identify compartments/cells responsive to estrogen, using immunohistochemistry, Western blotting, in situ hybridization, and RT-PCR analyses. Expressions of ERalpha and ERbeta in the rat penis were age dependent at both mRNA and protein levels, with the most intense signals being observed during the perinatal period and declining thereafter with age. Initial signals (fetal d 17) of ERalpha were localized to the mesenchyme and subepithelial stroma and later (postnatal d 2) to the corpus spongiosus, corpus cavernosus, and urethral epithelia. ERbeta was initially detected by postnatal d 2 and was localized diffusely in corpus spongiosus and cavernosus in immature rats. In the adult, both ERs were concentrated largely to the urethral epithelia and vascular and neuronal structures. The present study provides the first evidence for ER expression in the penis. Thus, our data add the penis to the list of estrogen-responsive tissues in males and provide a base and insight for future studies aimed at investigating a functional role of estrogen in the penis, especially in development.

Effects of tamoxifen and estradiol on estrogen binding sites in the urogenital tract: an experimental study in the rabbit

The aim of the study was to investigate the effects of estradiol and tamoxifen alone and in combination on the estrogen binding site status of the urogenital tract in the rabbit. Bilaterally ovariectomized rabbits were divided into four groups of six. Whereas the control group received no treatment, the remaining rabbits were treated with estrogen or/and tamoxifen. Cytosolic and nuclear fractions were isolated from the uterus, vagina, urethra and urinary bladder and used for binding site assay, by radioligand binding. The total weight of the rabbit vagina and uterus was increased significantly by both estradiol, tamoxifen and the combination of the two. The total weight of the urethra was increased only in the combination group. The cytosol binding site was downregulated by estradiol, tamoxifen and combination in the uterus, and in the vagina. Cytosol binding site in the urethra was not detected. The combination of estrogen-tamoxifen markedly reduced the nuclear binding site in the urethra and decreased affinity of the nuclear binding sites in all three tissues. The data suggest that tamoxifen has a specific ability to modulate the transcriptional activity of the estrogen binding sites in the rabbit urogenital tract.

Co-localization of androgen receptor with estrogen receptor beta in the lower urinary tract of the male rat

PURPOSE

Androgens and estrogens influence voiding. In this study their target sites in the lower urinary tract of the male rat were identified.

MATERIALS AND METHODS

Cryosections of the bladder body, bladder neck, prostatic urethra, mid proximal urethra and prostatic autonomic ganglia of adult male rats were immunostained with specific estrogen receptor alpha, estrogen receptor beta (ERbeta) or androgen receptor (AR) antibodies. The sections were then examined under conventional, fluorescence or confocal fluorescence microscopy.

RESULTS

Co-expression of AR and ERbeta in the urothelium, bladder smooth muscle cells, proximal urethra striated muscle cells and neurons in the autonomic ganglia of the prostatic plexus suggests that estrogen and androgen have direct effects in the lower urinary tract.

CONCLUSIONS

The local interaction of AR and ERbeta in the hormonal control of voiding is an intriguing possibility.

The concept of uroselectivity

Alpha1-adrenoceptor antagonists have been shown to decrease both the voiding and storage symptoms of benign prostatic hyperplasia (BPH). Based on the assumption that these symptoms can be attributed to the consequences of the increase in outflow resistance caused by noradrenaline stimulation of stromal alpha1-adrenoceptors in the enlarged prostate, prostatic alpha1-adrenoceptors have become a target for therapeutic interventions. In some patients, alpha1-adrenoceptor antagonists in common clinical use produce intolerable side effects which may be attributed to action on non-prostatic alpha1-adrenoceptors. Therefore, attempts have been made to find alpha1-adrenoceptor antagonists that have selective effects on the prostate ('uroselective' agents), to maintain efficacy in uroflow and eliminate adverse effects. The term uroselectivity has been used in various contexts, but drugs may be discussed as uroselective from a receptor pharmacological, physiological, or clinical perspective. Provided that the alpha1-adrenoceptor subtype in the prostate, bladder neck and urethra is uniform, unique, and cannot be found in other parts of the body, drugs with selectivity for this receptor could be called uroselective. However, available evidence suggests that (1) more than one alpha1-adrenoceptor subtype can be found in the lower urinary tract, and that the main alpha1-adrenoceptor mediating contraction still remains to be definitely defined; (2) the receptor(s) is (are) most probably not unique to the lower urinary tract, and (3) alpha1-adrenoceptor sites outside the prostate (with still undefined subtypes) may contribute to the lower urinary tract symptoms of BPH. Therefore, it does not seem possible to define uroselectivity in terms of selectivity for the alpha1-adrenoceptor(s) occurring in the prostate. Several animal models have been developed where the potency order of effects of various alpha1-adrenoceptor antagonists on blood pressure and urethral pressure have been measured simultaneously. Such models can be useful when screening drugs that may be developed for therapeutic use, but they also have limitations, since side effects that may be dose limiting clinically are not always related to a decrease in blood pressure. Certainly, a drug may be said to have physiological or functional uroselectivity if it lowers outflow resistance more effectively than it affects other defined physiological functions. A clinically meaningful definition of uroselectivity can only be made in man and considers desired effects on obstruction and lower urinary tract symptoms relative to adverse effects.

Function and distribution of beta3-adrenoceptors in rat, rabbit and human urinary bladder and external urethral sphincter

1. Activation of beta-adrenoceptors causes relaxation of the urinary bladder and contraction of the external urethral sphincter, which consists of fast-contracting skeletal muscles. A beta2-adrenoceptor agonist, clenbuterol, recently has been developed as a therapeutic drug for the treatment of urinary incontinence, however beta2-adrenoceptor agonists have undesirable effects on cardiac and striated muscle function. 2. In this study, we compared the effects of the beta2-adrenoceptor agonist, clenbuterol and of a novel beta3-adrenoceptor agonist, GS332, on urinary bladder and external urethral sphincter function in rat, rabbit and human. We also determined the distribution of beta3-adrenoceptors in human urinary bladder and external urethral sphincter, using radioligand-binding techniques. 3. Clenbuterol induced marked relaxations in rat, rabbit and human urinary bladder smooth muscles and also induced marked contractions in rat periurethral striated muscles (external urethral sphincter), while GS332 induced marked relaxations in rat and human, but not in rabbit, urinary bladder smooth muscles and induced small contractions in rat periurethral striated muscles. 4. The radioligand binding studies showed presence of beta2- and beta3-adrenoceptors in human urinary bladder, external urethral sphincter and abdominal rectus muscles. The affinities of GS332 were the highest in urinary bladder and the lowest in the skeletal (abdominal rectus) muscles, while the affinities of clenbuterol were similar in urinary bladder, external urethral sphincter and the skeletal (abdominal rectus) muscles. 5. These results suggest that GS332 could, similarly clenbuterol, have a role in the treatment of urinary frequency and urinary incontinence.

Elastic fibres in the vesicourethral junction and urethra of the guinea pig: quantification with computerised image analysis

Elastic fibres, which are intimately associated with collagen, a major component of the urethra, have been assumed to contribute to the resting urethral closure pressure. The Miller stain for elastin was used to demonstrate elastic fibres in cryostat sections of guinea pig bladder base, vesicourethral junction (VUJ) and urethra. Computerised image analysis was employed to objectively quantify these fibres. Both male and female guinea pigs showed significantly greater amounts of circularly disposed elastic fibres in the VUJ than in the other 2 regions examined. This particular disposition of fibres may be responsible for imparting resiliency and plasticity to the VUJ, allowing it to distend and recoil repeatedly in response to urine outflow. Furthermore, the elastic fibres may be partly responsible for the passive occlusive force in this region. Elastic fibres in the distal urethra were not quantified because of their relative paucity. Sagittal sections of the urethra revealed a mass of longitudinally arranged elastic fibres localised almost exclusively within the mucosa, submucosa and longitudinal smooth muscle layer. Functionally, this arrangement may exist to facilitate urethral length changes that occur in micturition.

Neurotransmitters in the human urethral sphincter in the absence of voiding dysfunction

The purpose of this study was to elucidate the neuroregulation of sphincteric relaxation by investigating the density of nerves containing acetylcholine, noradrenaline, neuropeptide Y (NPY), galanin, vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) in the urethral sphincter in patients without a voiding disorder. The complete urethral sphincter (from the bladder neck to beyond the striated external sphincter) was excised from four male and four female adult cadavers and one male and one female fetus. In transverse paraffin or cryostat sections, the above transmitters were identified by histochemical methods. The striated sphincter was densely innervated by cholinergic nerves. Adrenergic nerves next to striated fibers were rare, but were present in all patients. NPY was seen rarely along striated fibers. In the smooth sphincteric component, noradrenaline-, acetylcholine-, NPY- and galanin-reactive nerves were observed frequently. Only functional studies can clarify the clinical implications of these results. Judging from NPY's scarcity in the striated sphincter no efferent function is anticipated. In the smooth component the frequent appearance of NPY, galanin and noradrenaline suggests a regulatory role for these transmitters.

In vitro ligation of ureters and urethra modulates fetal mouse bladder explants development

The compliance of the bladder which accommodates the holding and voiding of urine is influenced by the amount and type of collagen deposited as well as the packing and organization of collagen fiber bundles. During fetal development, the accumulation of urine within the bladder lumen is associated with the maturation of the bladder's wall. Fetal mouse bladders can undergo maturation as organ cultured explants in defined medium. Polarized light optics of Sirius red-stained sections of fetal mouse bladders in organ culture for 4 days showed that the ligation of both ureters and urethra promoted more orderly packing of collagen fiber bundles within the luminal edge of the lamina propria compared to unligated bladder explants. It is proposed that ligation causes differences in the development and organization of the collagen fiber bundles within the bladder wall. These differences are due to either increases in intravesical pressure, the accumulation of growth factors within the lumen or a combination of both.

Characterization, localization and distribution of alpha1 adrenoceptor subtype in male rabbit urethra

PURPOSE

The subtype specificity, localization and distribution of urethral alpha1-adrenoceptors were studied in the male rabbit urethra.

MATERIALS AND METHODS

The properties of the urethral alpha1-adrenoceptors were investigated using radioligand receptor binding and light microscopic autoradiography with [125I]iodo-2-[b-(4-hydroxyphenyl)-ethylaminomethyl]tetralone (HEAT), and immunohistochemistry with monoclonal anti-alpha smooth muscle actin and anti-alpha sarcomeric actin antibodies.

RESULTS

Saturation experiments with [125I]HEAT demonstrated the presence of significant amounts of a single high affinity binding site for alpha1 adrenoceptors in the male rabbit urethra. The pharmacological profile of the alpha1 adrenoceptors in rabbit urethra, determined by inhibition experiments with subtype selective alpha1 adrenoceptor antagonists, was characterized by the following rank order of potency of inhibition constants (Ki values): prazosin < or = WB 4101 < spiperone < 5-methylurapidil < BMY 7378. The pKi values for the rabbit urethra were correlated with the pKi values for rat spleen, submaxillary glands, and vas deferens and for those reported for cloned alpha1d receptors with correlation coefficients of 0.68, 0.929, 0.909, and 0.523, respectively.

CONCLUSIONS

The pharmacological characterization demonstrates the predominance of alpha1A or alpha1A + alpha1B adrenoceptor subtype(s) in male rabbit urethral smooth muscle. Furthermore, the autoradiographic and immunohistochemical studies show a heterogeneous distribution of alpha1 adrenoceptors along the longitudinal axis of the urethra, within the smooth muscle fibers, with the receptors being localized more densely in the proximal than in the distal urethra.

Evidence for a strychnine-sensitive mechanism and glycine receptors involved in the control of urethral sphincter activity during micturition in the cat

Micturition in the decerebrate cat is characterized by a coordinated bladder contraction and a simultaneous decrease in external urethral sphincter (EUS) efferent activity. Without the suppression of EUS activity, voiding is significantly impaired, resulting in a state sometimes referred to as bladder-sphincter dyssynergia. The aim of the present study was to determine whether glycinergic inhibition contributes to the suppression of EUS activity during micturition evoked by bladder distension or electrical stimulation of the pontine micturition center (PMC) in decerebrate cats. Using subconvulsive intravenous doses of strychnine (0.1-0.24 mg/kg), we examined changes in bladder and EUS electroneurographic (ENG) activity during micturition. Following subconvulsive doses of strychnine, tonic EUS ENG activity increased during bladder filling in five of six animals. In the presence of strychnine, it was possible to evoke reflex bladder contractions of similar duration and peak pressure to those observed before strychnine administration. However, there was an absence of suppression of EUS ENG activity during the bladder contractions in all the animals. To determine whether the changes in sphincter activity could be due to strychnine acting at glycine receptors on EUS motoneurons, sacral spinal tissue was processed for a structural protein (gephyrin) associated with the glycine receptor. Motoneurons in Onufs nucleus in S1 were identified using choline acetyltransferase immunohistochemistry and subsequently processed with a gephyrin monoclonal antibody. Abundant gephyrin labeling was evident throughout Onufs nucleus. Since Onufs nucleus is made up of EUS and other motoneuron populations, a sample of antidromically identified urethral and anal sphincter motoneurons were intracellularly labeled with tetramethylrhodamine dextran (TMR-D) and then processed with the gephyrin antibody. Using dual-beam confocal microscopy, gephyrin immunoreactivity was observed on the soma and proximal processes of individual EUS motoneurons in both male and female animals. It was concluded that a strychnine-sensitive mechanism contributes to the suppression of sphincter activity normally observed during voiding. Although glycinergic inhibition may affect several components of the circuitry responsible for micturition, it appears that the suppression of EUS motoneurons during micturition may be partly due to a direct glycinergic inhibition of the EUS motoneurons.

Different organization of collagen fibrils in stress-incontinent women of fertile age

OBJECTIVE

The objective was to test the hypothesis that stress urinary incontinence in women is correlated to changes in the paraurethral connective tissue ultrastructure and metabolism.

METHODS

Transvaginal biopsies were obtained from the paraurethral connective tissue in women of fertile age with stress urinary incontinence and in matched continent controls. All the stress-incontinent women were characterized with urodynamic investigation. In the biopsies, collagen concentration, measured as hydroxyproline, and the degree of extraction by pepsin digestion were quantified. Proteoglycan composition and concentration were analyzed using Alcian blue precipitation, followed by electrophoretic separation and quantification. Using Northern blots mRNA levels for the collagens I and III, the small proteoglycans decorin and biglycan, and the large proteoglycan versican, were quantified. Collagen organization was examined with transmission electron microscopy and the diameters of collagen fibrils were analyzed with an interactive image analysis system (IBAS, Zeiss/Kontron).

RESULTS

The biochemical and morphological analyses exposed a significant difference in the paraurethral connective tissue between stress urinary incontinent women before menopause and comparable controls. The collagen concentration was almost 30% higher and the diameters of the collagen fibrils were 30% larger in the incontinent group of women. Also the organization of the collagen fibrils differed, with considerably higher cross-linking. A higher level of mRNA for collagen I and III in the incontinent group indicates that the differences can be related to an altered collagen metabolism. No change of proteoglycan amount or composition was observed, resulting in a significantly lower proteoglycan/collagen ratio in the incontinent group of women.

CONCLUSION

Stress urinary incontinence in fertile women is associated with a change in collagen metabolism resulting in an increased concentration of collagen and larger collagen fibrils. These alterations should result in a more rigid form of extracellular matrix, suggesting a connective tissue with impaired mechanical function.

Paraurethral connective tissue in stress-incontinent women after menopause

OBJECTIVE

To study whether stress urinary incontinence after menopause is correlated to changes in the paraurethral connective tissue ultrastructure and metabolism.

METHODS

Transvaginal biopsies were obtained from the paraurethral connective tissue in stress urinary incontinent women after menopause with and without estrogen replacement therapy, and from comparable controls. All the stress-incontinent women underwent urodynamic investigation. In the specimens, collagen concentration, measured as hydroxyproline, and the degree of extractability by pepsin digestion, were quantified. Proteoglycan composition and concentration were analyzed using Alcian Blue precipitation, followed by electro-phoretic separation and quantification. Using Northern blots, mRNA levels for the collagens I and III, the small proteoglycans decorin and biglycan, and the large proteoglycan versican, were quantified. Collagen structure was examined with transmission electron microscopy, and the diameters of collagen fibrils were analyzed with an interactive image analysis system (IBAS, Zeiss/Kontron).

RESULTS

No significant difference in paraurethral connective tissue biochemistry or ultrastructure was registered between women with stress incontinence and controls. Estrogen replacement therapy resulted in a lower collagen concentration both between the controls (p = 0.02) and between the incontinent women (0.02). In the women with stress incontinence also the extractability by pepsin digestion was higher in the group with estrogen treatment (p = 0.004), indicating a decrease in cross-linking. The proteoglycan/collagen ratio was higher in the control group with estrogen treatment compared to untreated (p = 0.02), but no difference was found between estrogen treated and untreated incontinent women. The median collagen fibril diameter was 15% larger in the incontinent group of women without estrogen therapy compared to the control group and 5% larger when comparing the incontinent group on estrogen replacement therapy to the corresponding control group.

CONCLUSION

The extracellular matrix of paraurethral connective tissue in stress urinary incontinent women after menopause reacted differently to estrogen replacement therapy compared to continent controls. In contrast to incontinent women of fertile age no major changes in collagen metabolism were found in stress urinary incontinent women after menopause.

Elastic fibre system of the female canine urethra. Histochemical identification of elastic, elaunin and oxytalan fibres

The elastic system fibres of the female urethra were investigated in seven dogs of different breeds. The fibres were stained and differentiated with orcein, Verhoeff's iron hematoxylin, and pararosanilin-based aldehyde fuchsin, with and without previous oxidation. Orcein and aldehyde fuchsin revealed some subepithelial longitudinally orientated delicate fibres (elaunin fibres) and numerous coarse longitudinal fibres (elastic fibres) in the deeper subepithelial connective tissue containing the vascular plexus, as well as a network of fibres of different calibers in the periurethral connective tissue. Elastic system fibres were also found in association with the sinusoids of the vascular plexus and the urethral smooth musculature. Verhoeff's iron hematoxylin only reacted distinctly with coarse (elastic) fibres. When applied following oxidation, aldehyde fuchsin disclosed an extensive meshwork of additional delicate fibres (oxytalan fibres) in the subepithelial connective tissue adjacent to the basement membrane. Oxytalan fibres were also discernible in the sinusoidal adventitia of the vascular plexus, as well as between smooth and striated muscle fibres. Due to the predominantly longitudinal orientation of the elastic system fibres and the low urethral resistance to manual expression of urine from the bladder post mortally, when the elasticity of the urethra is still intact and the activity of other continence factors can be excluded, the elastic tissue is not judged to be a major contributory factor to urinary continence.

Immunohistochemical distribution of rabbit polyclonal antiurinary protein 1 antibody in the female (Skene's gland) and male prostate: new marker for neuroendocrine cells?

Using rabbit polyclonal antiurinary protein 1 antibody to study the female prostate (Skene's gland) and the male prostate, characteristic localizations patterns appeared in single cells and groups of cells. The majority correspond to cells positive for neuroendocrine markers. In the cytoplasm, cells positive for protein 1 were most frequently found in the epithelial lining of the female urethra, in the pars prostatica of the male urethra, and in the ducts of the female and male prostate where the lining consisted of pseudostratified columnar epithelium. Their occurrence rate was far lower among secretory and basal cells of the male and female prostate glands. The cells with protein 1 corresponded to those displaying positivity for chromogranin A, silver staining by the Grimelius and less by the Sevier-Munger method, and by neuron specific enolase. Using the Masson-Hamperl argentaffin method, positive cells were only exceptionally found. The cells positive for protein 1, and particularly chromogranin A, and characterized by Grimelius positivity, contained different amounts of neuroendocrine granules and varied in size and shape. The majority of these cells had contact with the lumen of male and female prostatic ducts (open type of neuroendocrine cells). In some cases of the male and female urethra and of the great paraurethral ducts, a remarkably high number of cells containing protein 1 corresponded to cells only containing neuron-specific enolase but not chromogranin A and other neuroendocrine markers. These cells can be considered stem cells responsible for the renewal of the uroepithelium of the urethra and prostatic ducts. Protein 1 may thus be a further, though presumably not specific marker for the identification of cells of the neuroendocrine system in the prostate of the male and female. This marker could well be used to study uroepithelium maturation. The corresponding immunohistochemical distribution of human protein 1 in neuroendocrine and other cells of the male and the female prostate provides another analogous functional and morphological parameter of prostatic tissue in both sexes and further evidence supporting the non-vestigial concept of the prostate in the female.

Ultrastructural analysis of primary human urethral epithelial cell cultures infected with Neisseria gonorrhoeae

In men with gonococcal urethritis, the urethral epithelial cell is a site of infection. To study the pathogenesis of gonorrhea in this cell type, we have developed a method to culture primary human urethral epithelial cells obtained at the time of urologic surgery. Fluorescent analysis demonstrated that 100% of the cells stained for keratin. Microscopic analyses indicated that these epithelial cells arrayed in a pattern similar to that seen in urethral epithelium. Using immunoelectron and confocal microscopy, we compared the infection process seen in primary cells with events occurring during natural infection of the same cell type in men with gonococcal urethritis. Immunoelectron microscopy studies of cells infected with Neisseria gonorrhoeae 1291 Opa+ P+ showed adherence of organisms to the epithelial cell membrane, pedestal formation with evidence of intimate association between the gonococcal and the epithelial cell membranes, and intracellular gonococci present in vacuoles. Confocal studies of primary urethral epithelial cells showed actin polymerization upon infection. Polyclonal antibodies to the asialoglycoprotein receptor (ASGP-R) demonstrated the presence of this receptor on infected cells in the primary urethral cell culture. In situ hybridization using a fluorescent-labeled probe specific to the ASGP-R mRNA demonstrated this message in uninfected and infected cells. These features were identical to those seen in urethral epithelial cells in exudates from males with gonorrhea. Infection of primary urethral cells in culture mimics events seen in natural infection and will allow detailed molecular analysis of gonococcal pathogenesis in a human epithelial cell which is commonly infected.

Urinary bladder-urethral sphincter dysfunction in mice with targeted disruption of neuronal nitric oxide synthase models idiopathic voiding disorders in humans

Idiopathic voiding disorders affect up to 10-15% of men and women. We describe bladder abnormalities in mice with targeted deletion of the gene for neuronal nitric oxide synthase which model the clinical disorders. The mice possess hypertrophic dilated bladders and dysfunctional urinary outlets which do not relax in response to electrical field stimulation or L-arginine. The mice also display increased urinary frequency.

Evidence for the presence of regional differences in the subtype specificity of muscarinic receptors in rabbit lower urinary tract

To elucidate the subtype specificity of muscarinic cholinergic receptors in mediating contractile responses in the lower urinary tract, we investigated contractile and biochemical properties of muscarinic receptors in bladder dome, bladder base and urethra of the rabbit. Isometric contractile response curves to increasing concentrations of carbachol were constructed in the absence and presence of various concentrations of subtype selective muscarinic antagonists. Bladder dome, bladder base, and urethra demonstrate different characteristics in terms of efficacy and potency with respect to carbachol-induced contractile responses. Emax values are significantly larger and ED50 values are significantly smaller in bladder dome and bladder base than in urethra. Calculation of the pA2 values, the negative logarithm of the antagonist affinity constant (KB), for a series of muscarinic antagonists, i.e., atropine (nonselective), pirenzepine (M1 selective), methoctramine (M2 selective), and 4-DAMP (M1/M3 selective) indicate that the carbachol-induced contractile response in bladder dome and bladder base is mediated through the M3 receptor subtype whereas the carbachol-induced contractile response in urethra is probably mediated through the M1 and/or M3 and possibly M2 subtypes. Muscarinic cholinergic antagonists inhibit [3H]quinulidinyl benzilate binding to bladder dome, bladder base and urethra with the following rank order of affinities: atropine > 4-DAMP > methoctramine > pirenzepine. The binding data indicate the predominance of the M2 receptor subtype in all three regions.

Neonatal estrogenization of the male mouse results in urethral dysfunction

PURPOSE

Analysis of voiding pattern, urodynamic measurements and immunohistochemical methods were performed in order to evaluate the effects of neonatal estrogenization on voiding functions of adult male mice.

MATERIALS AND METHODS

Metabolic cages were used for recording the voiding volumes and frequencies. Bladder pressure and mean flow during voiding were measured in transvesical cystometry. Location of estrogen receptors and organization of smooth muscles in lower urinary track were demonstrated using immunohistochemical staining.

RESULTS

Neonatally estrogenized (neoDES) male mice had lower voided urine volumes (the average voided urine volume and average of the three largest volumes) and higher voiding frequencies than control mice. In transvesical cystometry, the maximum bladder pressure during the high-frequency oscillation phase of voiding was significantly elevated. The average urinary flow rate was decreased.

CONCLUSIONS

Urodynamically, these findings are consistent with the concept that neonatally estrogenized mice have infravesical obstruction. The predominance of estrogen receptors in the periurethral region and changes in urethral smooth muscle cells immunocytochemically stained with alpha-actin-antibody support the concept of urethral wall musculature as a target of estrogen action.

Effects of ovariectomy on mechanical properties and collagen content in rabbit lower urinary tract smooth muscle

Fourteen female rabbits underwent ovariectomy or were sham-operated six weeks before investigation. Detrusor and urethral strips (longitudinal and circular urethral muscle fibers were studied separately) were prepared and length-tension relations studied in organ baths experiments. In addition, the specimens were examined for collagen content. Maximal active tension in the detrusor, longitudinal and circular urethral preparations, determined as the response to K+ (124mM), was reached when the length of the strips was 178 +/- 8% (n = 7), 153 +/- 9% (n = 5), and 127 +/- 5% (n = 7) of the resting length, respectively. Ovariectomy did not alter the length for development of maximal active tension. In detrusor strips, ovariectomy caused a significant increase in maximal active tension from 39 +/- 7 mN (sham-operated rabbits) to 79 +/- 11 mN (p < 0.01), despite an unchanged relative amount of smooth muscle. The maximal active tension produced in the urethra was lower (15-25 mN) than in the detrusor, and not significantly affected by ovariectomy. Approximately 40% of the dry defatted tissue weight of the detrusor consisted of collagen, whereas corresponding value in the urethra was 50-60%. Ovariectomy had no effect on tissue collagen concentrations. In conclusion, ovariectomy for six weeks did not affect the passive mechanical properties or the collagen concentration in rabbit lower urinary tract smooth muscle, but increased the responsiveness of the detrusor muscle to K+ (124 mM).

Development of peptide-containing nerves in the human fetal prostate gland

Immunohistochemical methods were used to study the developing peptidergic innervation of the human fetal prostate gland in a series of specimens ranging in gestational age from 13 to 30 wk. The overall innervation of each specimen was visualised using protein gene product 9.5 (PGP), a general nerve marker. The onset and development of specific neuropeptide-containing subpopulations were investigated using antisera to neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), bombesin (BOM), somatostatin (SOM), leu-enkephalin (l-ENK) and met-enkephalin (m-ENK). In addition the occurrence and distribution of presumptive noradrenergic nerves was studied using antisera to dopamine-beta-hydroxylase (D beta H) and tyrosine hydroxylase (TH). At 13 wk numerous branching PGP-immunoreactive (-IR) nerves were observed in the capsule of the developing prostate gland and surrounding the preprostatic urethra but the remainder of the gland was devoid of nerves. The majority of nerves in the capsule contained D beta H and TH and were presumed to be noradrenergic in type while other nerves (in decreasing numbers) contained NPY, l-ENK, SP and CGRP. Nerves associated with the preprostatic urethra did not contain any of the neuropeptides under investigation. At 17 wk the density of nerves in the capsule had increased and occasional m-ENK-, VIP- and BOM-IR nerve fibres were also observed. In addition PGP, D beta H-, TH-, NPY- and l-ENK-IR nerves occurred in association with smooth muscle bundles which at 17 wk were present in the outer part of the gland. Occasional PGP-IR nerves were also present at the base of the epithelium forming some of the prostatic glands. At 23 wk some of the subepithelial nerves showed immunoreactivity for NPY, VIP or l-ENK. At 26 wk smooth muscle bundles occurred throughout the gland and were richly innervated by PGP, D beta H and TH-IR nerves while a less dense plexus was formed by NPY- and l-ENK-IR nerves together with a few m-ENK-IR nerves. Occasional smooth muscle-associated varicose nerve fibres showed immunoreactivity for SP, CGRP, VIP or BOM although the majority of these types of nerve formed perivascular plexuses. Also at 26 wk numerous varicose nerve fibres were observed in association with the prostatic acini, the majority of such nerves containing NPY with a few showing immunoreactivity to VIP, l-ENK, SP or CGRP.(ABSTRACT TRUNCATED AT 400 WORDS)

[Effects of chronic low-frequency electrical stimulation on the external urethral sphincter of male rabbits--electrophoretic analyses of myosin light and heavy chain isoforms]

The present study investigates the effects of chronic low-frequency electrical stimulation on the external urethral sphincter (EUS) of rabbits through the biochemical analysis of the isoforms of myosin light and heavy chains. Twenty-eight adult male rabbits were used in the test. Of these, the EUS of 14 rabbits were continuously stimulated directly at 1.8 Hz, 0.8 msec, 5.0 V with an implantable electrical cardiac pacemaker for more than 10 weeks. The other 14 rabbits were used as the control group and were nurtured under the same conditions as the stimulated group but without the electrical stimulation. Upon conclusion of the stimulation program, the urethra was removed from all 28 rabbits. The portion of the urethra containing the EUS (from the middle of the prostate to the pelvic diaphragm) was cut transversely into thin serial sections and glycerinated. The glycerinated muscle fibers were then isolated under a stereomicroscope and samples for electrophoretic analysis were prepared. Two-dimensional electrophoresis according to the procedure of O'Farrell for myosin light chains and SDS-PAGE containing 40% glycerol for myosin heavy chains were carried out. The molar ratio of myosin subunits was determined by quantification through the dye elution process. The average percentages of slow myosin light chain molecules in 8 unstimulated and 8 stimulated EUS were 33.4 +/- 8.9% (mean +/- SD) and 70.1 +/- 12.8%, respectively. The average percentages of slow myosin heavy chain molecules in 6 unstimulated and 6 stimulated EUS were 17.6 +/- 5.7% and 40.2 +/- 7.1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of carbachol and norepinephrine on phosphatidyl inositol hydrolysis and cyclic AMP levels in guinea pig urinary tract

Muscarinic cholinergic and adrenergic agonist-induced changes in [3H]-phosphatidyl inositol (PI) hydrolysis and cyclic AMP (cAMP) levels were measured in guinea pig ureter, urethra and bladder dome. In the ureter, carbachol, norepinephrine and phenylephrine rapidly increased PI hydrolysis and basal cAMP levels, but did not decrease forskolin-stimulated cAMP levels. In the bladder dome, norepinephrine and phenylephrine produced a rapid but transitory increase in PI hydrolysis, but did not affect forskolin-stimulated cAMP levels. Carbachol produced a rapid and sustained increase in PI hydrolysis and also, at high concentrations, decreased forskolin-stimulated cAMP levels. In the urethra, norepinephrine and carbachol rapidly decreased forskolin-stimulated cAMP levels and later increased PI hydrolysis. Our data suggest that the predominant second messenger system in the ureter, dome, or urethra is more dependent on the tissue than on the agonist. These tissue-specific, agonist-induced rapid changes in second messenger levels may help coordinate the contraction-relaxation phenomena necessary for urinary tract function.

Non-adrenergic, non-cholinergic relaxation and levels of cyclic nucleotides in rabbit lower urinary tract

Electrical field stimulation at 12 Hz produced urethral relaxation and increased the tissue cyclic GMP content by 111 +/- 36% (n = 6, P < 0.05). Pretreatment with zaprinast (10 microM) increased the tissue cyclic GMP content in response to electrical stimulation by 160 +/- 56% (n = 7, P < 0.05). The nitric oxide synthase inhibitor NG-nitro-L-arginine (0.1 mM) and methylene blue (50 microM) inhibited electrically-induced cyclic GMP accumulation. Methylene blue only partially inhibited urethral relaxation, whereas NG-nitro-L-arginine caused complete inhibition. Electrical stimulation of urethral preparations did not affect the tissue levels of cyclic AMP. Administration of sodium nitroprusside increased the cyclic GMP content in the urethra and detrusor. Administration of isoprenaline increased the detrusor cyclic AMP content, but no change in urethral cyclic AMP levels could be detected. Cyclic GMP related drugs (sodium nitroprusside, 8-bromo-cyclic GMP) reduced urethral tone by 67-75% and detrusor tone by 13-39%. These results suggest that nerve-induced relaxation of the rabbit urethra is associated with an increase in cyclic GMP, but not cyclic AMP content. Synthesis of NO is essential for both nerve-mediated relaxation and cyclic GMP accumulation. The urethral smooth muscle tissue is more sensitive to cyclic GMP-activating drugs than the detrusor smooth muscle.

The estrogen receptor expression in the male rabbit urethra and prostate following castration

The influence of castration on estrogen receptor (ER) expression in the male rabbit prostate and urethra, was investigated immunohistochemically and biochemically in 18 mature male, rabbits 14 days after bilateral orchiectomy, and in 15 controls. Immunohistochemical scores of ER were increased significantly in the prostatic stroma and the urethral submucosa (p < 0.05 Mann-Whitney), while the increase in the urothelium was not significant. Biochemically, the ER content was 87.4 +/- 42.6 f mol/mg protein in the normal prostate, and 190.0 +/- 28.0 f mol/mg protein following castration. The corresponding values for the posterior urethra were 228.3 +/- 43.2 f mol/mg protein and 354.9 +/- 60.1 f mol/mg protein. In both cases the increase was not significant. We conclude, that ERs in the prostate and the urethra of the male rabbit can be modified by hormonal manipulation. ERs may therefore be functionally active and not rudimentary.

Human urethral epithelium: immunohistochemical demonstration of secretory IgA

Male human urethral epithelium was treated for the immunohistochemical demonstration of secretory IgA in order to verify its own possible antimicrobial properties. An intense immunoreactivity for sIgA in the entire cytoplasm and at the luminal surface of the apical epithelial cells was observed. The results suggest that sIgA play a prominent role in the local defense mechanisms of the urethra. Such mucosal defense mechanisms may be of significance in the defense of the urinary and genital tract against ascending infections.

Urinary prostate specific antigen levels after radical prostatectomy

It was recently demonstrated that urinary prostate specific antigen (PSA) is discordant with serum PSA in many patients after radical prostatectomy. This observation led to the speculation that elevated urinary PSA in the face of undetectable serum PSA may indicate early disease recurrence. We measured urinary PSA levels in 30 patients who had undergone radical prostatectomy for prostate carcinoma and 7 patients who had undergone cystoprostatectomy for bladder cancer. PSA levels of randomly collected urine samples ranged from 0.00 to 22.9 ng./ml. and 0.01 to 8.37 ng./ml., respectively. There was no correlation among urinary and serum PSA levels, pathological stage or type of operation. In 14 patients who had undergone radical prostatectomy and who had measurable levels of urinary PSA voided specimens were divided into initial stream and end stream voided samples. The PSA levels in the end stream voided samples were significantly less than the initial stream sample in 12 of the 14 patients. In men who had undergone radical prostatectomy urethral swab samples were analyzed for PSA. Of 26 patients 24 had detectable levels of urethral swab PSA (range 0.01 to 39.04 ng./ml., median 0.93 ng./ml.). Urethral swab PSA levels did not correlate with serum PSA values or pathological stage of disease. Of 7 patients who had defunctionalized urethras after radical cystoprostatectomy 5 had significantly elevated PSA in the urethral wash or swab samples (range 4.3 to 24.5 ng./ml.). Immunohistochemical analysis of urethrectomy specimens demonstrated positive staining for PSA in 3 of 4 specimens. We conclude that the major source of urinary PSA following total prostatectomy is the urethra itself rather than residual prostate tissue. Measuring serial urinary PSA appears to have limited value in monitoring patients after radical prostatectomy. Whether this urethral PSA can ever contaminate the serum levels of PSA after radical prostatectomy is currently under investigation.

Biochemical characterization and quantitation of the collagenous components of urethral stricture tissue

The collagenous composition of normal and strictured human urethral tissue was analyzed qualitatively by immunohistochemistry and quantitatively by 2-dimensional gel electrophoresis of cyanogen bromide digested tissue. Histological comparison of the normal and strictured urethral tissue showed that the normal urethral spongiosum was replaced by densely packed connective tissue fibers interspersed with fibroblasts in the strictured tissue. The immunohistochemical analysis of urethral tissue identified the presence of types I and III collagen fibers in normal spongiosum and in the connective tissue scar of strictured tissue. Estimation of the collagen type III:I ratio using scanning densitometry revealed a CB5:CB8 peptide ratio of 0.357 +/- 0.058 in the normal tissue, while the urethral stricture tissue had a CB5:CB8 ratio of 0.203 +/- 0.079 (p = 0.010). Total collagen content, as determined by hydroxyproline analysis, revealed no statistically significant differences between control and strictured tissue. Therefore, the normal urethral spongiosum was comprised of 75.1% type I collagen and 24.9% type III collagen. In contrast, the type I collagen in urethral stricture tissue was increased (83.9%), with a corresponding decrease in type III collagen (16.1%). This alteration in the ratio of collagen type III:I may explain the fibrotic noncompliant nature of urethral stricture scar tissue.

The L-arginine/nitric oxide pathway in the rabbit urethral lamina propria

A non-adrenergic, non-cholinergic (NANC)-mediated relaxation has been demonstrated in the female rabbit urethral lamina propria, both in response to electrical stimulation and after administration of acetylcholine. The present study was performed to investigate if these relaxations are mediated via the L-arginine/nitric oxide (NO) pathway. In the lamina propria of the female rabbit urethra, numerous NADPH diaphorase-positive, fine varicose nerve fibres were observed both around arteries, in and around smooth muscle bundles, and in arterial endothelium. Since NADPH diaphorase histochemistry may be a marker of NO synthase-containing neurons, this finding suggests the occurrence of NO synthase in this tissue. Isolated preparations of the rabbit urethral lamina propria, contracted by noradrenaline, produced frequency-dependent NANC relaxations in response to electrical field stimulation, and concentration-dependent NANC relaxations in response to acetylcholine. Electrically induced relaxations were possible to evoke even in preparations where acetylcholine-induced relaxation was poor or absent. Pretreatment with the NO synthase inhibitor, NG-nitro-L-arginine (L-NOARG) reduced the maximum relaxation obtained at 30 Hz to 12% of the control response. NG-nitro-D-arginine (D-NOARG) had no effect. The effects of L-NOARG were antagonized by the addition of L-arginine. Acetylcholine relaxed noradrenaline-precontracted strips by 36%; vasoactive intestinal polypeptide (VIP) reduced the contraction by 95%. L-NOARG, but not D-NOARG, abolished or reversed acetylcholine-induced relaxations, but failed to reduce the relaxations produced by VIP. The results demonstrate the occurrence of NADPH diaphorase-positive nerve fibres in the lamina propria of the female rabbit urethra.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative analysis of adrenergic alpha-1 and alpha-2 receptors in human prostatic urethral tissue

We measured the adrenergic alpha-1 and alpha-2 receptors in 3 types of prostatic tissue (prostatic urethral mucosa, prostatic adenoma and prostatic capsule) in a group of patients with benign prostatic hypertrophy (BPH) and in another group without BPH, using radioligand binding techniques. In all tissues examined, more alpha-1 and alpha-2 receptors were found in the hypertrophy group than in the other group. The increase in density of these receptors in the hypertrophy group was most marked in the prostatic adenoma. The density of alpha-1 and alpha-2 receptors was almost the same in the adenoma in both groups. The prostatic capsule and urethra in both groups contained more alpha-1 than alpha-2 receptors. Both receptors were found more in the adenoma than in the other 2 tissues in both groups. These results suggest that alpha-1 and alpha-2 receptors both play an important part in the symptoms of benign prostatic hypertrophy.

Neuropeptidergic innervation of the human male distal urethra and intrinsic external urethral sphincter

The innervation of the human male distal urethra and intrinsic external urethral sphincter was investigated by immunohistochemical techniques. The innervation density was low. In the urethra neuropeptide, and vasoactive intestinal polypeptide positive nerves were found in the muscular layer, calcitonin gene-related peptide, galanin and PHI nerves were localized in the epithelium. In the intrinsic external urethral sphincter NPY and galanin nerves were quite numerous between the striated muscle bundles, calcitonin gene-related peptide, vasoactive intestinal polypeptide and PHI were only seen occasionally as thin fibres.

Human papillomavirus genomes in male urethral cells

Sixty-four samples of urethral cells from male sexual partners of women with genital human papillomavirus (HPV) infection were analyzed for the presence of HPV types 6, 11, 16, and 18 by polymerase chain reaction (PCR) followed by slot blot hybridization. Additional samples from 37 of these subjects were analyzed for the presence of viral cytopathic effects by conventional cytology. By PCR, HPV DNA was detected in 21% (14/64) of samples. By cytology, 16% (6/37) of the samples showed cellular changes consistent with HPV infection. Polymerase chain reaction and cytology results were concordant for presence and absence of HPV in 5 and 28 cases, respectively. Three additional HPV-positive cases were obtained with PCR in the cytologically negative samples. The cytologic abnormalities were found to be associated with the presence of both low-risk HPV types and meatal acetoreactivity. On the contrary, HPV DNA positivity by PCR was unrelated to viral type and peniscopic findings. Urethral HPV infection was detected by PCR in 30% of males with visible penile lesions and in 18% of those without. These results indicate that PCR analysis of urethral samples is a helpful adjunct to cytology for the detection of HPV DNA in absence of cytologic evidence of infection.

Tachykinin NK1 receptor in the guinea-pig isolated proximal urethra: characterization by receptor selective agonists and antagonists

1. The tachykinin receptor mediating contraction of the guinea-pig isolated proximal urethra has been characterized by use of receptor selective agonists and antagonists. All experiments were performed in the presence of peptidase inhibitors (bestatin, captopril and thiorphan, 1 microM each) in order to reduce peptide degradation. 2. The natural tachykinins, substance P and neurokinin A produced a concentration-dependent contraction of rings of the proximal urethra which approached the same maximum (about 50% of the response to 80 mM KCl). Substance P (EC50 155 nM) was slightly (3.6 times) more potent than neurokinin A (EC50 560 nM). 3. The tachykinin NK1 receptor selective agonist, [Sar9]substance P sulphone (EC50 62 nM), was slightly more potent than substance P and produced the same maximal response of natural tachykinins. The NK2 receptor selective agonist, [beta Ala8] neurokinin A(4-10), was active only at microM concentrations and its maximal effect did not exceed 20% of that to substance P or neurokinin A. The NK3 receptor selective agonist, senktide, was ineffective up to 30 microM. 4. The response to [Sar9]substance P sulphone was antagonized in a competitive manner by either (+/-)-CP 96,345 (pA2 7.75, slope - 1.10) or GR 82,334 (pA2 7.31, slope - 1.26), which are selective NK1 receptor antagonists, while it was unaffected (up to 10 microM) by MEN 10,376, a selective NK2 receptor antagonist. 5. The response to 10 microM [beta Ala8]neurokinin A (4-10) was abolished by either 0.2 microM (+/-)-CP 96,345 or 1 microM GR 82,334, suggesting the involvement of NK1 receptors.6. Electrical field stimulation (5 and 10 Hz, 0.25 ms, 100 V, trains of 5 s duration) produced tetrodotoxin-sensitive phasic contractions of the urethra which were abolished by atropine plus phentolamine (3 microM each). Capsaicin (1 microM) produced a small transient contraction of the urethra which was abolished by ( )-CP 96,345 (0.1 microM). ( )-CP 96,345 did not modify the response to electrical field stimulation.7. We conclude that tachykinin NK, receptors are the main if not the only mediators of the contractile response of guinea-pig proximal urethra to peptides of this family and that this preparation is useful for assessing the affinities of various ligands for the NK, receptor. Endogenous tachykinins released from peripheral endings of capsaicin-sensitive primary afferents produce urethral contraction by activating NK, receptors.

[Quantitative analyses of alpha-adrenoceptors in human prostatic capsule, adenoma and urethra--a comparison between normal prostate and hypertrophied prostate]

The adrenergic alpha-1 and -2 receptors in the three layers of the prostate (capsule, adenoma and urethra) were measured in humans with or without benign prostatic hypertrophy to examine the differences between the hypertrophied and non-hypertrophied (normal) prostate. Both alpha-1 and -2 receptors were found to exist in similar amounts in prostatic adenoma of both hypertrophied and normal prostate groups. In the prostatic capsule and urethra of both groups alpha-1 receptors were more abundant than alpha-2 receptors. Both alpha-1 and -2 receptors in all three prostatic layers were found to be increased significantly in hypertrophied group compared to normal group. Further more the increases in alpha-1 and -2 receptors of hypertrophied group were most remarkable in prostatic adenoma. These results seems to demonstrate that not only alpha-1 but also alpha-2 receptors play some important roles in benign prostatic hypertrophy.

Immunocytochemistry of paraneurons in the female urethra of the horse, cattle, sheep, and pig

The aim of this study is to describe the presence of neuroendocrine (NE) cells (paraneurons), producing biogenic amines and/or peptidergic hormones, in the female urethra of cattle, sheep, pigs, and horses, by means of histochemical and double labeling immunofluorescent techniques. 5-Hydroxy-tryptamine-, chromogranin A-, cholecystokinin- and somatostatin-containing NE cells are present in the urethral epithelium of all the species studied, with the unique exception of the lack of somatostatin cells in the horse. Paraneurons containing 5-hydroxytryptamine colocalized with chromogranin A or cholecystokinin were also found in all subjects. Such active substances are hypothesized to play a role in the contraction of the urethral musculature, emission of urogenital fluids, and inhibition of endocrine and exocrine secretions.