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PubMed1997

Carbon monoxide-induced relaxation and distribution of haem oxygenase isoenzymes in the pig urethra and lower oesophagogastric junction.

1. The distribution of the carbon monoxide (CO) producing enzymes haem oxygenase (HO)-1 and -2 was studied by immunohistochemistry in the pig's lower urinary tract, including bladder extramural arteries, and the oesophagogastric junction (OGJ). In isolated smooth muscle from the urethra and the OGJ, the mechanisms for CO-induced relaxations were characterized by measurement of cyclic nucleotide levels and by responses to the guanylate cyclase inhibitor methylene blue and some K+ channel inhibitors. 2. HO-2 immunoreactivity was observed in coarse nerve trunks within the smooth muscle of the urethra and OGJ, and in nerve cell bodies of the enteric plexuses of the OGJ. Furthermore, the vascular endothelium of the intramural vessels of the urethra, bladder and OGJ, and the extramural vessels of the bladder, displayed HO-2 immunoreactivity. Two different antisera against HO-1 were used, but only one displayed immunoreactivity in neuronal structures. HO-1 immunoreactivity, as displayed by this antiserum, was seen in nerve cells, coarse nerve trunks and varicose nerve fibres in the smooth muscle of the urethra and OGJ. Some HO-2 and/or HO-1 (as displayed by both HO-1 antisera) immunoreactive cells with a non-neuronal appearance were observed within the smooth muscle of the OGJ, bladder and urethra. 3. In the urethral preparations, exogenously applied CO (72 microM) evoked a relaxation amounting to 76 +/- 6%. The relaxation was associated with an increase in cyclic GMP, but not cyclic AMP, content. CO-evoked relaxations were not significantly reduced by treatment with methylene blue, or by inhibitors of voltage-dependent (4-aminopyridine), high (iberiotoxin, charybdotoxin) and low (apamin) conductance Ca(2+)-activated, and ATP-sensitive (glibenclamide) K+ channels. Bladder strips, and ring preparations from the extramural arteries of the bladder, did not respond to exogenously administered CO (12-72 microM). 4. In the OGJ, exogenously applied CO evoked a relaxation of 86 +/- 6%, which was associated with an increase in cyclic GMP, but not cyclic AMP, content. Treatment with 30 microM methylene blue raised the spontaneously developed muscle tone, and reduced the maximum relaxation evoked by CO to 33 +/- 9%. Addition of 4-aminopyridine, apamin, glibenclamide, iberiotoxin, charybdotoxin or glibenclamide had no effect on the relaxations. 4-aminopyridine (0.1-1 mM), iberiotoxin (0.1 microM) and charybdotoxin (0.1 microM) increased the spontaneously developed tone, and a combination of charybdotoxin and apamin reduced CO-induced (24 microM CO) relaxations. 5. The present findings demonstrate the presence of HO in both neuronal and non-neuronal cells in the pig OGJ and lower urinary tract. CO produces relaxation of the smooth muscle in the OGJ and urethra, associated with a small increase in cyclic GMP concentration in both regions. Relaxations evoked by CO in the urethra do not seem to involve voltage-dependent, low and high conductance, or ATP-dependent K+ channels. However, in the OGJ relaxations evoked by CO can be attenuated by methylene blue and a combination of charybdotoxin and apamin.

Animals↗
PubMed2001

Fluorescence urethroscopy following instillation of 5-aminolevulinic acid: a new procedure for detecting clinical and subclinical HPV lesions of the urethra.

OBJECTIVE: To report early clinical experience with intraurethral instillation of 5-aminolevulinic acid (ALA) for the detection of clinical lesions (condyloma acuminata) and subclinical human papillomavirus (HPV) lesions of the urethra, not visible by conventional endoscopy. SUBJECTS AND SETTING: Eighty-four men with clinical diagnosis of condyloma acuminata were examined for urethral HPV lesions at the Department of Urology, Ludwig Maximilian University, Munich, Germany. METHODS: The anogenital areas of the patients were thoroughly examined using a magnifying glass before and after application of 5% acetic acid. Conventional as well as fluorescence urethroscopy were performed 1 h after topical application of 0.1% ALA for 15 min. A sensitive colour charge-coupled device camera for fluorescence video inspection was used with spectral analysis. Biopsies were taken for histological examination and HPV detection by polymerase chain reaction (PCR). RESULTS: Forty-three of 84 men attending our clinic for condyloma acuminata had clinical HPV lesions of the urethra. Condylomas of the proximal urethra were found by conventional endoscopy in eight patients. Fluorescence urethroscopy detected additional subclinical lesions in 13 men. All lesions were HPV infections of the urethra confirmed histologically or by PCR. In nine of these subclinical urethra lesions low-risk HPV types (HPV6, 11, 34) were found. Four lesions were associated with high-risk types (HPV18, 31,52,58). CONCLUSIONS: Fluorescence urethroscopy is a promising diagnostic procedure for detecting subtle clinical and subclinical HPV lesions of the urethra, that are normally not visualized by conventional endoscopy. Generally, urethroscopy is recommended in all cases of externally visible condylomas of the urethra after therapy.

Adolescent↗
PubMed2001

Three-dimensional ultrasound of the female urethra: comparing transvaginal and transrectal scanning.

OBJECTIVES: To compare transvaginal and transrectal three-dimensional ultrasound in determining the morphology and measurements of the female urethra. DESIGN: Sixty-five women who had not had surgery for incontinence or pelvic floor descent had transvaginal and transrectal sonography using a 7.5-MHz mechanical sector endoprobe with three-dimensional facilities. The multiplanar display of the scanned volumes allowed detailed morphologic assessment of the urethra and the measurement of distances and volumes. Statistical endpoints were: sagittal urethral diameter, maximum rhabdosphincter length and thickness, maximum thickness of the smooth muscle complex, and the volumes of the rhabdosphincter and the smooth muscle complex. Values were compared between the two approaches using Student's t-test and Bland-Altman analysis. RESULTS: Both vaginal and rectal scans were feasible. However, significant differences between the two approaches were found for the sagittal diameter of the urethra (8.4 +/- 1.9 mm on vaginal vs. 11.5 +/- 2.2 mm on rectal scans, P < 0.01) and the transverse diameter of the urethra's smooth muscle complex (11.2 +/- 0.3 mm on vaginal vs. 8.6 +/- 0.2 mm on rectal scans, P < 0.001). No other variables showed significant differences. Compression of the urethra and displacement under the symphysis pubis were observed when the ultrasound probe was applied vaginally. Bland-Altman analysis showed acceptable variability for differences of distances but considerable variability for the differences of volumes. CONCLUSION: The female urethra can be examined both vaginally and rectally by three-dimensional ultrasound. A transvaginally applied probe seems to have a compression effect on the urethra.

Adult↗
PubMed2003

Structure of the pelvic and penile urethra--relationship with the ducts of the sex accessory glands of the Mongolian gerbil (Meriones unguiculatus).

The urethra is the main place of entry for sexually transmitted pathogens. However, there is little literature on the morphology of the urogenital system, principally the urethra and ducts of the sex accessory glands. The Mongolian gerbil is an insectivorous, herbivorous and monogamous rodent with nocturnal habits; it has been used successfully as a laboratory animal since the 1960s. Therefore, the objective of the present paper was to describe the structure and ultrastructure of the urethra and its relations to the ducts of the accessory sex glands of the Mongolian gerbil (Meriones unguiculatus), contributing to the understanding of the reproductive biology of the rodent and aiming to provide data for future experimental studies. Conventional techniques of light and scanning electron microscopy were utilized. The urethra and ducts of the accessory sex glands are similar to those of the albino rat and the mouse. However, there is variation in drainage type among accessory sex glands for the inner urethra. The ducts of the seminal vesicle, the ductus deferens, drain their contents independently into the ampullary duct that opens in the urethra. The ducts of the prostate, coagulating and bulbourethral glands drain their contents independently into the urethra.

Animals↗
PubMed2001

Model of counter-current transfer from vagina to urethra in postmenopausal women.

BACKGROUND: Low-dose vaginal oestrogens are effective in treating post-menopausal urogenital atrophy without inducing endometrial proliferation. We aimed to assess whether this dichotomic effect could be the result of a preferential vagina-to-urethra transfer via a counter-current transfer of oestrogens from vagina to the arterial blood supplying the urethra. Due to the impossibility of obtaining blood samples from urethral arteries, and since the nature of counter-current exchange of substances is similar to the transfer of heat, we investigated cold transfer throughout the anterior vaginal wall to the vesical trigone and urethra. METHODS: Plastic tubes filled with cold saline were inserted into the vagina of 30 menopausal women. Temperatures were recorded at the vesical trigone and at three different urethral sites. Comparisons were performed 2 and 4.5 min after starting of cooling, and 4.5 min after removal of tubes. RESULTS: The urethra cooled significantly more than the bladder. Urethral cooling was not homogeneous; distal sites of the urethra cooled significantly more than proximal site and bladder despite a larger distance to the vaginal cooling device. CONCLUSIONS: Distribution of cold from the vagina to the urethra is not the result of simple diffusion and mechanisms of preferential distribution may exist from the vagina to the middle and low part of the urethra.

Administration, Intravaginal↗
PubMed2001

Urethra is more sensitive to ischemia than bladder: evidence from an in vitro rat study.

PURPOSE: Experimental studies have demonstrated that ischemia may induce significant bladder dysfunction. Because multiple causes leading to bladder ischemia also decrease urethral perfusion, we assessed the effect of in vitro ischemia on the contractile responses of the rat bladder and urethra. We evaluated the hypothesis that neurogenic dysfunction in urethral ischemic injury occurs before myogenic dysfunction is present. We also compared contractile responses of the rat bladder and urethra to in vitro ischemia followed by reoxygenation. MATERIALS AND METHODS: Isolated strips of rat bladder detrusor muscle and prostatic urethra were incubated in normal physiological medium and stimulated electrically and chemically. In vitro ischemia was produced by incubating tissue in ischemic medium for 30 or 60 minutes. The maximal tension and maximal rate of tension generated were analyzed digitally before ischemia and after ischemia followed by reoxygenation. RESULTS: We demonstrated that after 30 minutes of ischemia followed by reperfusion the maximal rate of tension generated decreased significantly only in the urethra and only in response to field stimulation. After 60 minutes of ischemia the decrease in urethral contractile responses was greater than the decrease in bladder contractile responses. Ischemia 60 minutes in duration caused a significant decrease in the maximal rate of tension generated as well as maximal tension in the urethra and bladder but only in response to field stimulation. CONCLUSIONS: This experiment demonstrates that the urethra is more sensitive to ischemic injury than the bladder. Our finding may explain the development and symptoms of urinary incontinence secondary to sphincteric damage before bladder dysfunction is present. We also demonstrated that in the bladder and urethra the response to field (neurogenic) stimulation is the most sensitive form of stimulation to ischemia.

Animals↗
PubMed1993

Human papillomavirus DNA in urine samples compared with that in simultaneously collected urethra and cervix samples.

A polymerase chain reaction was used to evaluate the occurrence of human papillomavirus (HPV) DNA in urine samples compared with that in urethra and cervix samples simultaneously collected with brushes. Of 138 presumably healthy military conscripts, 12 (8%) had HPV DNA-positive urethra samples and 8 (5%) had HPV DNA-positive urine samples. Both the urine and urethra cell samples of five men were positive, with identical types found in the paired specimens. Seven had HPV DNA-positive urethra samples only, and three had HPV DNA-positive urine samples only. Five of 7 urethra samples from males and 11 of 12 urethra samples from females, who were among patients consulting a clinic for adolescents, were positive for HPV DNA. Among those patients whose urethras were positive for HPV DNA, the corresponding urine samples of 3 of the 5 men and all the 11 women were also positive, with one or two HPV types being in common within the paired samples. Among female patients referred to a colposcopy clinic, 49% (241 of 489) of the cervical cell samples and 38% (187 of 489) of the urine specimens were found to be HPV DNA positive. Of the patients whose cervixes were positive for HPV DNA, 65% (158 of 241) of the simultaneously collected urine samples were also positive for HPV DNA. On the other hand, 84% (158 of 187) of the patients with HPV DNA in their urine also had HPV DNA in their cervical samples. Although not all individuals with genital HPV infections could be identified as HPV positive by analysis of urine samples, at least in epidemiological surveys in which invasive samples are difficult to obtain, such as from children, analysis of urine could be an alternative means of identifying HPV DNA.

Adolescent↗
PubMed2006

Ex vivo biomechanical properties of the female urethra in a rat model of birth trauma.

Stress urinary incontinence (SUI) is the involuntary release of urine during sudden increases in abdominal pressures. SUI is common in women after vaginal delivery or pelvic trauma and may alter the biomechanical properties of the urethra. Thus we hypothesize that injury due to vaginal distension (VD) decreases urethral basal tone and passive stiffness. This study aimed to assess the biomechanical properties of the urethra after VD in the baseline state, where basal muscle tone and extracellular matrix (ECM) are present, and in the passive state, where inactive muscle and ECM are present. Female rat urethras were isolated in a rat model of acute SUI induced by simulated birth trauma. Our established ex vivo system was utilized, wherein we applied intraluminal static pressures ranging from 0 to 20 mmHg. Outer diameter was measured via a laser micrometer. Measurements were recorded via computer. Urethral thickness was assessed histologically. Stress-strain responses of the urethra were altered by VD. Quantification of biomechanical parameters indicated that VD decreased baseline stiffness. The passive peak incremental elastic modulus of the distal segment in VD urethras was less than for controls (1.84 +/- 0.67 vs. 1.19 +/- 0.70 x 10(6) dyne/cm(2), respectively; P = 0.016). An increase was noted in passive low-pressure compliance values in proximal VD urethras compared with controls (9.44 +/- 2.43 vs. 4.62 +/- 0.60 mmHg(-1), respectively; P = 0.04). Biomechanical analyses suggest that VD alters urethral basal tone, proximal urethral compliance, and distal stiffness. Lack of basal smooth muscle tone, in combination with these changes in the proximal and distal urethra, may contribute to SUI induced by VD.

Animals↗
PubMed1989

Pharmacological comparison of the isolated whole urethra model to urethral strip methodology.

Urethral strips provide a sensitive method for quantitative pharmacology; however, it is not clear if the physiological response of the whole urethra to pharmacological agents can be extrapolated from these data. The intent of this study was to investigate whether the linear contraction of strips is consistent with the ability of the intact urethra to alter resistance to flow. To measure the effect of drugs on the ability of the intact urethra to alter resistance to flow in the absence of endogenous influences, we developed an in vitro whole rabbit urethra model. We characterized the effect of norepinephrine in the absence and presence of alpha-adrenergic antagonists (prazosin, yohimbine, and LY253352) on intraurethral pressure which was measured during constant saline infusion using a Statham pressure transducer. We compared this to the contractile function of urethral strips. The pA2 values for alpha-adrenergic antagonists, LY253352, prazosin, and yohimbine were 8.17 +/- 1.5, 6.49 +/- 1.2, and 5.58 +/- 0.9, respectively, as determined in the whole urethra. The pA2 values for these antagonists determined in urethral strips were as follows: LY253352 8.72 +/- 1.2; prazosin 7.52 +/- 1.5, and yohimbine 5.6 +/- 0.84. Pharmacologically, the whole urethra model and isolated strips appeared to respond similarly to alpha-adrenergic agonists and antagonists, and thus both models would be suitable for pharmacological studies on the normal urethra.

Animals↗
PubMed1995

Estrogen receptors in the human male bladder, prostatic urethra, and prostate. An immunohistochemical and biochemical study.

The distribution and quantity of estrogen receptors (ERs) in the human male bladder, prostatic urethra and the prostate were studied in eight males with recurrent papillomas of the bladder or monosymptomatic hematuria (median age 61 years), 14 men undergoing transurethral resection due to benign prostatic hyperplasia (median age 70 years), and nine men undergoing cystectomy due to malignant tumour of the bladder (median age 70 years). In the first group of patients, biopsies for immunohistochemical examination were obtained from the bladder vault, bottom, both side-walls, the trigone area, and the mid-portion of the prostatic urethra, and in the second group from three locations of the prostatic urethra (bladder neck, mid-portion and veramontanum). In the third group, tissue specimens were taken from the vault of the bladder, prostatic urethra, and the prostate, for immunohistochemical as well as biochemical analysis. In the first group, ERs were found in three out of eight specimens of the prostatic urethra, and in one of these, ERs were confined to periurethral glands. ERs could not be demonstrated in any of the bladder-biopsies. In the second group, ERs were not found in the bladder neck, but were seen in four preparations from the veramontanum and in two from the midportion of the urethra. ERs were located in the urothelium and periurethral glands. In the third group, ERs were seen immunohistochemically in the prostatic urethra (two cases) and the prostatic stromal tissue (two cases). ERs could be demonstrated in the bladder neither by immunohistochemistry nor biochemically.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

The expression of receptors for estrogen and epithelial growth factor in the male rabbit prostate and prostatic urethra following castration.

In the lower urinary tract of the male rabbit, estrogen receptors (ERs) are restricted to the urethra and the prostatic stroma. At present, the function of ERs in these tissues is not known. Epithelial growth factor (EGF) stimulates proliferation of epidermal and epithelial tissues, and several animal studies have indicated that EGF is regulated by estrogen. On this background, we have studied the effect of castration on the expression of ERs and EGF receptors in the rabbit prostatic urethra and prostate. Twelve male rabbits were studied fourteen days after castration, and eight normal rabbits were included as controls. In the control group, ERs were found in the urothelial lining and lamina propria of the prostatic urethra, and in the prostatic stroma. EGF receptors were demonstrated in the epithelial lining of the prostatic urethra and the glandular epithelium of the prostate. Following castration, the expression of ERs, assessed as the increase in the number of positively stained specimens, increased significantly in the lamina propria of the prostatic urethra and the prostatic stroma. EGF receptor expression increased significantly in the epithelial lining of the prostatic urethra. In the prostate, the increase was not significant. The results give no support to the view that ERs play role in the regulation of EGF receptors in the rabbit prostatic urethra nor the prostate.

Animals↗
PubMed1994

[Significance of transrectal ultrasonography in surgery for stress urinary incontinence and cystocele. Assessment of the bladder neck suspension by measuring posterior urethrovesical angle and angle of inclination of the upper urethra].

We treated 42 females (26 with genuine stress urinary incontinence, 13 with incontinence and cystocele, and 3 with cystocele) with bladder neck suspension using transrectal ultrasonography during operation. The optimum tightness of suspension was decided by adjusting the posterior urethrovesical angle to about 90 degrees in 26 patients with genuine stress urinary incontinence accompanied with flattened posterior urethrovesical angles and by adjusting the angle of inclination of the upper urethra to about 10 degrees in 16 patients with cystocele accompanied with rotationally descended urethra. Urinary continence was achieved in 35 of 39 patients presenting with urinary incontinence. Three patients with cystocele without urinary incontinence remained dry after the operation. The average of maximum urinary flow rate significantly increased after operation. The angles of inclination of the upper urethra measured on the ultrasonogram during operation corresponded well with those measured on the post-operative lateral urethrocystogram. In 26 patients without cystocele, the angles of inclination of the upper urethra and the posterior urethrovesical angles were correlated significantly on the pre-operative urethrocystograms. Roentgenographic changes in pre- and post-operative urethrocystograms showed concomitant restoration in the angles of inclination of the upper urethra and in the posterior urethrovesical angles as well as significant elevation of the bladder neck. Present results indicate that the angles of inclination of the upper urethra measured by transrectal ultrasonography during operation as well as the posterior urethrovesical angles are useful and reliable to decide the optimum tightness of bladder neck suspension for the patients with stress urinary incontinence accompanied with rotationally descended urethra.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

Dynamic transurethral sonography and 3-dimensional reconstruction of the rhabdosphincter and urethra: initial experience in continent and incontinent women.

OBJECTIVE: The purpose of this study was to evaluate the female urethra and the striated urinary sphincter, the rhabdosphincter (RS), by means of dynamic transurethral sonography and sonographic 3-dimensional (3D) reconstructions. METHODS: In 15 female patients with urinary stress incontinence (mean age, 67.5 years) and 5 continent women (mean age, 48.3 years), morphologic characteristics and function of the RS and urethra were examined with a 10-MHz transurethral ultrasound transducer. With the help of a mechanical pullback system, the transducer was slowly retracted to scan the whole urethra and the RS from the bladder neck to the urethral orifice. Subsequently, 3D reconstructions of the urethra using an integrated computer system were performed. The RS as well as the length of the urethra were investigated under contracted and noncontracted conditions to measure contractility of the RS and dynamic changes of the lower urinary tract. RESULTS: Partial or complete loss of RS function was detected in patients with stress incontinence. The findings on sonography were found to correlate well with the grade of incontinence. Furthermore, under contraction of the RS, a median increase in urethral length was observed. In incontinent patients, the increase in the urethral length was statistically significantly less (P = .04), which was related to the reduced contractility of the RS. CONCLUSIONS: Dynamic transurethral sonography with subsequent 3D reconstructions allows for assessment of function and morphologic characteristics of the RS and urethra. Normal contraction of the RS results in an elongation of the urethra.

Adolescent↗
PubMed2002

The antimicrobial defense mechanism of the female urethra: a reassessment.

PURPOSE: This review of the literature and study of the cytology of the urethra were done to define the potential role of the female urethra as a staging site for urinary tract infection and examine the evidence for a urethral defense mechanism. MATERIALS AND METHODS: We re-analyzed data on the quantitative microbiology of the female urethra published 3 decades ago, reviewed the literature on the initiation of ascending urinary tract infections, the cytology and anatomy of the urethra, and performed studies of the morphology of urethral cells in boys and girls, men, menstruating and menopausal women, and women with acute cystitis. We also considered clues about the urethral microenvironment provided by gonococcal cervicitis and urethritis. RESULTS: We found strong statistical evidence that the female urethra has a powerful antimicrobial defense mechanism, which appears to differ in women with and without recurrent urinary tract infections. We corroborated the findings of previous investigators that the female urethra is lined by cells identical to those of the vagina that respond similarly to estrogens. We found immature basal and parabasal cells in children, and a modest inflammatory response to urinary tract infection. CONCLUSIONS: The female urethra may provide a favorable environment for colonization by uropathogens but it is protected by a powerful defense mechanism. This mechanism may be explained by the shedding of uropathogens bound to exfoliating urethral cells, trapping of bacteria by mucus secreted by the paraurethral glands, intermittent washout by urine, local production of Ig, cytokines and defensins and mobilization of leukocytes.

Adult↗
PubMed2003

[Single stage reconstructive operations of the male urethra].

UNLABELLED: The male urethra with its anatomic and tissue characteristics demands a differential approach in its reconstruction. The single stage operations, with using of a different plastic material as a treatment of some diseases of the male urethra (hypospadias, strictures), are already quite common to the urological practice. The authors are offering a retrospective analysis to the reconstructive operations of the male urethra with using a plastic material from the preputium and the skin of the penis. MATERIALS AND METHODS: For a period of 10 years 94 patients were followed ont: hypospadias--51 (53.9%); strictures--27 (28.7%); fistulas--16 (18%). Were described different operative techniques, but in all patients were used a one stage act. In patients with hypospadias we used five different techniques according to the sort of hypospadias. In patients with strictures we used three methods: with preputial flap; with circular flap from the dorsum of the penis and with a parallel longitudinal to the urethra flap from the ventral surface of the penis. RESULTS: From the first group of patients we had 17 (33.3%) with anterior hypospadias, 28 (54.9%) with middle, and 6 (11.8%) with posterior hypospadias. We achieved a full correction of the penis in 96.1% of the cases. We marked postoperative fistulas in 7 (13.7%) patients. In the second group of patients we marked 4 (14.8%) cases with postoperative Fistulas; restrictures in 2 (7.4%) cases and diverticul of the urethra in 1 (3.8%) case. In the third group fistulas were formed after urethroplasty in 11 (68.7%) cases and traumas and uroflegmons in 5 (31.3%) cases. We marked refistulisation in 5 cases. CONCLUSIONS: The urethroplasty with pedicular skin flaps from the preputium and the skin of the penis is a method of choice in patients with anterior strictures of the urethra. The single stage reconstructive operations of the male urethra are quite effective and promising.

Adolescent↗
PubMed1981

[Canine urethra as a model for experimental studies on urethral strictures (author's transl)].

Of all commonly used laboratory animals, the dog seems especially suited for transurethral experiments on the urethra when using normally available urological instruments. Because of its particular anatomy only the pelvic portion of the urethra in male dogs is available for study. In animals weighing at least 20 kg this segment is wide enough to permit insertion of instruments of up to F 24 size. Anatomically, this segment corresponds to the proximal segment of the bulbous portion of the urethra in man, i.e. there is no corpus cavernosum urethrae surrounding the urethra. Experiments in this segment require a perineal urethrostomy, the construction of which is associated with a high complication rate. The pelvic urethra of the male dog does not differ structurally from that of the female dog. Experiments on the female canine urethra can therefore be performed equally well and with less complications. Urethral strictures can be simply and effectively created by circular transurethral electrocoagulation of the urethral wall. With extensive urethral wall coagulation, temporary complete urinary retention may be observed postoperatively, which is due to extensive edema of the affected area.

Animals↗
PubMed1996

Functional characterization of alpha-1-adrenoceptor subtypes in the prostatic urethra and trigone of male rabbit.

The effects of alpha-1-adrenoceptor antagonists on the concentration-response curves (CRC) to phenylephrine and oxymetazoline have been studied in prostatic urethra and trigone of male adult rabbits (28 wk old). WB4101 and phentolamine, at low concentrations which should preferentially antagonize the alpha-1A-adrenoceptor subtype, did not modify the oxymetazoline-induced contraction of both prostatic urethra and trigone, suggesting that alpha-1A-adrenoceptors are not activated under these conditions. In urethra, pretreatment with 50 microM chloroethylclonidine (CEC), significantly reduced the maximal contraction to both agonists to 60 and 70% of control, respectively. In trigone, CEC decreased the maximum contraction to phenylephrine, but not to oxymetazoline, by 50%. In addition, CEC shifted to the right the CRC to both agonists. These results suggest the presence of an alpha-1B-adrenoceptor in both rabbit urethra and trigone. Exposure to prazosin (0.01-1 microM) significantly shifted to the right the CRC to phenylephrine (pA2 or affinity values without CEC treatment: 7.77 and 7.96 in urethra and trigone respectively; with CEC pretreatment: 7.49 and 7.42, respectively). When oxymetazoline was used as an agonist and in the presence of CEC, prazosin was unexpectedly weak in urethra with an affinity value of 6.70, although the antagonist potency was not modified in trigone (affinity 7.38). These values suggest that alpha-1-adrenoceptor agonists contract rabbit urethra and trigone through activation of alpha-1-adrenoceptors displaying low affinity for prazosin. Whether this receptor coincides with the alpha-1L- or alpha-1N-subtype remains to be clarified.

Adrenergic Agonists↗
PubMed2002

Hydrodissection technique to preserve the thin distal urethra when correcting chordee without hypospadias.

PURPOSE: We introduce a hydrodissection technique to preserve the thin distal urethra when treating chordee without hypospadias. MATERIALS AND METHODS: A total of 18 patients with chordee but without hypospadias were surgically treated in 3 years, including 7 (38.9%) with a segment of thin distal urethra. A hydrodissection technique was used to preserve the thin distal urethra in 6 patients with a mean age plus or minus SD of 9.0 +/- 3.6 years. Artificial erection was induced after circumcision and penile skin degloving. Tunica albuginea plication to correct residual chordee was needed in only 1 patient. The thin distal urethra was covered by preputial subcutaneous tissue in 3 cases and by Y to I spongioplasty in 3. RESULTS: All 6 thin distal urethras were preserved. The thin distal urethra was a mean of 23.3 +/- 3.9 mm. long and mean followup was 17.8 months. Postoperatively penile cosmesis was excellent in all patients and urinary flow was normal. CONCLUSIONS: Using the hydrodissection technique to preserve the thin distal urethra simplifies the operation of correcting chordee without hypospadias by avoiding additional urethroplasty and tunica albuginea plication for residual chordee.

Adolescent↗