Anatomic limitations of prostatic urethra in using cylindrical stents

The use of metal stents for the relief of prostate obstruction in the elderly has increased in popularity since 1980. The finding that fine metal wire stents become covered with prostatic epithelium led to the recent use of stents that can be left in place permanently. Because the prostatic urethra does not always conform to the cylindrical shape of these stents, and because the bladder neck/urethral angle is not a right angle and may not be circular in outline, problems may occur with positioning and subsequent inadequate epithelial covering. Three-dimensional imaging of the prostatic urethra using transrectal ultrasound scanning during voiding may give additional help in defining the variety of possible shapes of this area, but more work on the compliance of prostate tissue and the shape of the prostatic urethral lumen is essential in order to improve stent design and reduce the risks and complications of these useful devices.

An increase of neuropeptide Y but not nitric oxide synthase-immunoreactive nerves in the bladder neck from male patients with bladder neck dyssynergia

PURPOSE

To determine the distribution of neuropeptides in male patients with bladder neck dyssynergia and benign prostatic hyperplasia.

MATERIALS AND METHODS

Bladder neck tissue, obtained from male patients with bladder neck dyssynergia (BND) and control patients with benign prostatic hyperplasia (BPH), was studied immunohistochemically for protein gene product 9.5 (a general neuronal marker), vasoactive intestinal polypeptide, neuropeptide Y, calcitonin gene-related peptide, substance P, growth associated protein 43 and nitric oxide synthase.

RESULTS

In the bladder neck from control patients, the greatest density of nerves contained protein gene product 9.5, followed in decreasing order by neuropeptide Y; vasoactive intestinal polypeptide; calcitonin gene-related peptide; nitric oxide synthase; substance P and serotonin. The neuropeptides were found in the smooth muscle and were also associated with blood vessels. In patients with BND there was a statistically significant increase (P < 0.05) in the density of protein gene product 9.5- and neuropeptide Y-immunoreactive nerves in the smooth muscle and the base of the mucosa but not in blood vessels in the bladder neck, while the density of the other neuropeptides studied, nitric oxide synthase and serotonin did not significantly change from that of control tissue. Growth associated protein 43-immunoreactive nerves were absent from the bladder neck from both groups of patients.

CONCLUSION

It is suggested that the increase in density of protein gene product 9.5- and neuropeptide Y-immunoreactive nerves, part of the sympathetic contractile system of the bladder neck, may exacerbate bladder outlet obstruction and thus play a role in the pathogenesis of BND.

A method of measuring fluid balance during transurethral resection of the prostate

OBJECTIVE

To design a practical system for non-invasively monitoring fluid balance during transurethral resection of the prostate (TURP) and other endoscopic procedures.

MATERIALS AND METHODS

Load cell transducers are incorporated into a platform placed under the operating table. Output is passed to a digital weighmeter and then to a portable computer. The raw data is filtered using software written by the authors (CAL) and the output displayed both numerically and graphically on the computer screen. The device was tested under laboratory conditions and then assessed in the clinical setting.

RESULTS

The device proved stable in both the laboratory and clinical settings. Examples of the common patterns generated during TURP are presented. The prototype has been used routinely in our practice to warn the surgeon and anaesthetist of fluid overload and has been used to monitor fluid balance in several studies.

CONCLUSIONS

This instrument provides a practical method of monitoring total fluid balance during TURP. It can be used with either general or regional anaesthesia and provides information not otherwise available. It provides an early warning of significant changes in total fluid balance, particularly irrigant fluid absorption. Use of this device serves to prevent development of the TUR syndrome, a potentially fatal complication of endoscopic surgery. Our ultimate aim is to produce a refined version that is simple, compact and cheap enough to be used routinely in all urological theatres. The cost of a single episode of intensive care for a patient developing iatrogenic complications from irrigant absorption would offset the cost of such a device.

Precautions and complications in the use of the urolume wallstent

The Urolume Wallstent was first used to treat urethral strictures in 1987. Its place in the treatment of urethral strictures is now well established and we have used it successfully in over 100 patients. Recent interest in alternative methods of treating benign prostatic hyperplasia (BPH) has led to the use of this and other stents in patients with symptomatic BPH who are a poor surgical risk. Over 270 patients have been treated by us with the Urolume Wallstent with satisfactory results. More recently we have also used this stent as an alternative to transurethral resection of the prostate in fat patients. Although the Urolume Wallstent is easy to use and clinically effective, complications can arise if proper care is not taken during its insertion. As the stent has become more widely used more problems and difficulties have been experienced. We discuss these and describe the precautions which should be taken in the use of this device in order to achieve the best results.

Cardiovascular performance and core temperature during transurethral prostatectomy

Hemodynamic performance and core temperature were recorded during transurethral prostatectomy in 52 patients who were stratified according to cardiac symptom score and then randomized to undergo standard (31) or isothermic (21) transurethral prostatectomy. During the standard procedure ambient temperature (21C) irrigant was used, while during isothermic prostatectomy warmed irrigant at 38C was used to prevent heat loss from the bladder, and a warming blanket and humidifying filter were used to decrease cutaneous and respiratory heat loss. Core temperature decreased by a mean of 0.8C (95% confidence interval -0.9 to -0.7) during standard transurethral prostatectomy and by 0.27C (-0.4 to -0.15) during the isothermic procedure. The standard prostatectomy group showed a significant hemodynamic response consisting of increased mean arterial pressure (p < 0.0002), increased index of systemic vascular resistance (p < 0.0001), bradycardia (p < 0.02), and decreased Doppler indexes of stroke volume (p < 0.005) and cardiac output (p < 0.001). The isothermic transurethral prostatectomy group was hemodynamically stable. These differences between the groups suggest that rapid central cooling exerted a significant effect on perioperative hemodynamic performance during transurethral prostatectomy.

Three-dimensional imaging of the prostatic urethra--an exciting new tool

OBJECTIVE

To evaluate the technique of three-dimensional (3-D) ultrasound imaging of the urethra and its application in both research and clinical practice.

PATIENTS AND TECHNIQUE

The study involved 23 patients: 10 with benign prostatic hyperplasia, four with urethral strictures, three post-insertion of prostatic stents, one with bladder neck dyssynergia, three post-transurethral resection of the prostate, and two with non-urological conditions. A transrectal ultrasound scan was initially performed to acquire a series of images of the urethra. These images were then reconstructed into a 3-D format.

RESULTS

The 3-D image of the urethra could be rotated on screen and viewed from any angle. The image could also be sliced at any plane to reveal the sectional view.

CONCLUSION

This new tool represents a major advance in imaging techniques and promises to provide new knowledge in understanding the hydrodynamics of the lower urinary tract. The precise geometry of the 3-D urethra will also help in the design of new stents.

A three month double-blind study of doxazosin as treatment for benign prostatic bladder outlet obstruction

OBJECTIVE

To evaluate the efficacy and tolerability of doxazosin in the treatment of bladder outflow obstruction resulting from benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

One-hundred and thirty-five patients with symptomatic urodynamically confirmed obstructive BPH were treated for 12 weeks with either doxazosin (67 patients) or placebo (68 patients) after an initial 2 week baseline evaluation. The main outcome measures were urodynamic and symptomatic evaluation for efficacy. Blood pressure and adverse events were monitored.

RESULTS

Data were obtained in 122 patients (60 doxazosin, 62 placebo). Doxazosin produced increases in both mean and maximum urinary flow rates of 1.01 ml/s and 3.2 ml/s respectively, compared with 0.21 ml/s and 2.2 ml/s on placebo. The increase in mean flow rate was statistically significant (P = 0.04), while that for maximum flow rate approached significance (P = 0.09). The maximum subtracted voiding pressure was substantially reduced (P = 0.007) and 19 of 53 (36%) patients had an increase in maximum flow rate of 50% or more compared with 9 of 54 (17%) on placebo (P = 0.024). Twelve weeks' therapy with doxazosin resulted in significant improvements (compared with placebo) in: hesitancy (doxazosin 26 of 46, placebo 11 of 43; P = 0.003), impaired urinary stream (doxazosin 31 of 55, placebo 16 of 48; P = 0.019) nocturia (doxazosin 22 of 56, placebo 10 of 54; P = 0.017) and urgency (doxazosin 27 of 45, placebo 16 of 42; P = 0.041). Frequency improved with doxazosin therapy (doxazosin 26 of 59, placebo 15 of 55; P = 0.062). Adverse events, most frequently dizziness and headache, were usually mild and transient and led to a discontinuation of doxazosin therapy in one patient. No clinically significant changes in sexual function or blood pressure were seen.

CONCLUSION

Doxazosin was well-tolerated and produced both urodynamic and symptomatic improvement in men with BPH, thereby providing a satisfactory alternative to existing drugs with the additional benefit of once daily dosage.

Renal adenocarcinoma in young adults

Renal adenocarcinoma is rare in young people. The prognosis of the condition would appear to be better in young people justifying a radical treatment rationale even in cases of advanced disease. This report describes a series of patients under the age of 30 with renal adenocarcinoma and a review of the literature. The possible mechanisms for the apparent improved survival of patients in this age group is discussed.

Comparative study of selective alpha 1-adrenoceptor blockade versus surgery in the treatment of prostatic obstruction

Alternative treatments for benign prostatic hyperplasia (BPH) are the source of much discussion at present. Pharmacotherapy has been demonstrated to have an increasing role in the management of BPH. This study contrasts the efficacy of the selective alpha antagonist prazosin as compared with placebo and the subsequent improvements seen following surgical treatment. Whilst selective alpha blockade has undoubted therapeutic efficacy the improvement in symptom scores and the objective urodynamic measure of the flow rate are not as marked as those seen following surgery.

The urolume, a permanently implanted prostatic stent for patients at high risk for surgery. Results from 5 collaborative centres

Ninety-six men considered unfit for prostatic surgery underwent the insertion of a permanently implanted super alloy mesh stent (Urolume) at 5 European centres. Ninety were able to void immediately, 2 required a second stent to enable them to void and 4 voided after a period of suprapubic catheter drainage. Seven patients required the subsequent insertion of a further stent to cover the prostatic urethra completely and in 8 cases the stent was removed. Objective and symptomatic evidence of relief of bladder outflow obstruction was shown throughout the period of study. Severe irritative symptoms were seen in the majority of patients for periods of up to 3 months and resulted in removal of the stent in 3. At 12 months, 15 of 27 patients who underwent cystoscopy had complete epithelialisation of the stent and in 11 cases there was more than 70% epithelialisation. Fourteen patients developed encrustation on exposed parts of the stent during follow-up. This was associated with the development of a urinary infection in 9. The positioning of the stent in subsequent studies has been altered to overcome this problem.

The prostatron transurethral microwave device in the treatment of bladder outflow obstruction due to benign prostatic hyperplasia

There is currently considerable interest in the development of non-surgical means of managing bladder outflow obstruction due to benign prostatic hyperplasia (BPH). We report the results of a 1-year follow-up of 140 men (mean age 67.2 years) presenting with symptoms of bladder outflow obstruction treated for 1 h in a single session by the Prostatron transurethral thermotherapy system. Symptom scores, using a system modified from Boyarsky, fell from baseline values of 23.7 to 11.6. Maximum urinary flow values increased from a mean of 10.1 to 12.4 ml/s. Although residual urine volumes decreased slightly, this was not statistically significant. A self-administered postal questionnaire returned by 114 patients 1 year after Prostatron treatment, and by 87 patients of similar age who had undergone transurethral resection of the prostate (TURP) in the same institution, revealed that patient satisfaction regarding the outcome of each procedure was higher for TURP than thermotherapy. However, more patients suffered sexual dysfunction after TURP than after microwave treatment. It was concluded that although treatment with the Prostatron device produces subjective and objective improvement in a proportion of patients with BPH, more work needs to be done to improve the overall results and to pre-identify patients who experience little or no benefit from this therapy.

Does residual urine predispose to urinary tract infection?

The relationship between the presence of post-micturition residual urine and urinary tract infection is unclear. We have performed a retrospective analysis of 342 studies on bladder emptying and compared the incidence of bacterial infection and pyuria in patients with residual urinary volumes of more or less than 100 ml. In patients with a residual volume > 100 ml 49/219 studies showed evidence of pyuria and 28/198 studies of patients whose residual urine was less than 100 ml showed evidence of infection. In cases where the residuals were > 100 ml 33/123 had evidence of pyuria and 19/109 infection. There was no significant increase in the rate of infection in patients with large residual urinary volumes, suggesting that there is no definite correlation between post-micturition residues and urinary tract infection.

A 12-week placebo-controlled double-blind study of prazosin in the treatment of prostatic obstruction due to benign prostatic hyperplasia

A series of 93 normotensive patients with benign prostatic hyperplasia and maximum urinary flow rates < 15 ml/s, treated at 2 hospital centres using an identical protocol, was randomly assigned to receive a 12-week course of treatment with prazosin or placebo in a double-blind parallel group trial. A total of 75 patients completed the study and were suitable for the final analysis. Prazosin was administered orally in doses of 0.5 mg and then 1 mg twice daily for 4 days and 2 mg twice daily for the remainder of the trial. Patients on treatment with prazosin exhibited a significantly increased maximum urinary flow rate as compared with placebo, with a significant reduction in maximum voiding detrusor pressure. Prazosin therapy did not produce a significant effect on either frequency or standard parameters of detrusor instability. A double-blind overall assessment of drug efficacy and tolerance significantly favoured prazosin therapy. A total of 30 patients receiving prazosin and 28 receiving placebo reported varied adverse effects. Eighteen patients were excluded from the final analysis, 10 being withdrawn because of adverse effects, 7 on treatment with prazosin and 3 in the placebo group. In long-term usage oral prazosin was well tolerated and appeared to improve obstructed voiding in patients with benign prostatic hyperplasia.

Haemodynamic evidence for cardiac stress during transurethral prostatectomy

OBJECTIVE

To compare haemodynamic performance during transurethral prostatectomy and non-endoscopic control procedures similar in duration and surgical trauma.

DESIGN

Controlled comparative study.

SETTING

London teaching hospital.

PATIENTS

33 men aged 50-85 years in American Society of Anesthesiologists risk groups I and II undergoing transurethral prostatectomy (20), herniorrhaphy (eight), or testicular exploration (five).

MAIN OUTCOME MEASURES

Percentage change from baseline in mean arterial pressure, heart rate, Doppler indices of stroke volume and cardiac output, and index of systemic vascular resistance, and change from baseline in core temperature.

RESULTS

In the control group mean arterial pressure fell to 11% (95% confidence interval -17% to -5%) below baseline at two minutes into surgery and remained below baseline; there were no other overall changes in haemodynamic variables and the core temperature was stable. During transurethral prostatectomy mean arterial pressure increased by 16% (5% to 27%) at the two minute recording and remained raised throughout. Bradycardia reached -7% (-14% to 1%) by the end of the procedure. Doppler indices of stroke volume fell progressively to 15% (-24% to -6%) below baseline at the end of the procedure, and the index of cardiac output fell to 21% (-32% to -10%) below baseline by the end of the procedure. The index of systemic vascular resistance was increased by 28% (17% to 38%) at two minutes, and by 46.8% (28% to 66%) at the end of the procedure. Core temperature fell by a mean of 0.8 (-1.0 to -0.6) degrees C. Significant differences existed between the two groups in summary measures of mean arterial pressure (p less than 0.05), Doppler indices of stroke volume (p less than 0.005) and cardiac output (p less than 0.005), index of systemic vascular resistance (p less than 0.0005), and core temperature (p less than 0.0001).

CONCLUSIONS

Important haemodynamic disturbances were identified during routine apparently uneventful transurethral prostatectomy but not during control procedures. These responses may be related to the rapid central cooling observed during transurethral prostatectomy and require further study.

Stricture disease: radiology of urethral stents

Self-expanding metal stents are emerging as an effective alternative treatment in the management of urethral obstruction. The radiologic studies of 33 men with anterior urethral strictures (subprostatic, n = 11; bulbar, n = 22) that had recurred despite repeated optical urethrotomy and dilation were reported. In all patients, the stricture was successfully treated with stent insertion. Urethrography performed 1 month later in 19 patients showed an irregular intrastent lumen of varying degrees due to a hyperplastic urothelial reaction confirmed at endoscopy the same day. Available follow-up urethrograms in seven patients at 3 months showed that the hyperplasia was settling, and by 6 months, the intrastent lumen was smooth and of good caliber. Urethrography revealed postoperative structures in 14 patients. Strictures seen at 1 month (n = 6) were due to initial stent misplacement and were treated with the insertion of a second stent. Strictures seen 3 months after insertion (n = 4) occurred within the stent lumen and were considered to be significant at endoscopy in only one patient. Strictures that developed 6-12 months after stent insertion (n = 4) were not within the stent and were considered to represent genuine new strictures.

Haemodynamic evidence for per-operative cardiac stress during transurethral prostatectomy. Preliminary communication

Haemodynamic changes were measured during routine transurethral prostatectomy (TURP). The heart rate and stroke volume fell progressively over the first 30 min of surgery, resulting in a steady reduction in cardiac output. There was a significant increase in left ventricular afterload from commencement of the procedure. These findings demonstrate that haemodynamic responses, which are not detectable using conventional methods of monitoring, occur during TURP. Increased left ventricular afterload indicates increased myocardial work and oxygen demand which could result in myocardial ischaemia. This may contribute to the increased cardiovascular morbidity and mortality which have been reported to occur after TURP. The possible underlying mechanisms are discussed.

European experience with the urethral Wallstent for urethral strictures

We describe the use of the urethral Wallstent in 71 patients with urethral strictures. The stainless steel stent is self expanding when released from its endoscopic introducer. The results over a 3-year period have been good with only mild discomfort and slight urethral leakage for up to 3 months. Migration, infection and encrustation have not been a problem and serial endoscopic review shows healing to be variable but complete in up to 12 months. It is considered that this simple endoscopic technique offers a simple, safe and effective alternative to multiple dilatations, urethrotomies and urethroplasty procedures in patients with bulbar urethral strictures.

Double-blind, placebo-controlled, cross-over study of flavoxate in the treatment of idiopathic detrusor instability

Detrusor instability occurs in approximately 10% of the adult population, producing troublesome symptoms. The pharmacotherapy currently available is usually only partially effective and cannot be adequately evaluated except under "blind" conditions because of the significant component attributable to placebo effects. The results of the present study revealed no advantage resulting from treatment with flavoxate, as assessed both subjectively and objectively. We suggest that this therapy does not appear to be beneficial in the medical management of detrusor instability.

Nerve fibre proliferation in interstitial cystitis

The aetiology of pain in interstitial cystitis is not understood, although it has been reported to be due to release of mediators from mast cell granules. Cystolysis and intravesical instillation of dimethyl sulphoxide have been shown to relieve pain in this condition. We have studied the nerve population within the bladder wall using immunohistochemical stains for protein gene product 9.5. A group of 18 cases of chronic interstitial cystitis and 12 controls; neuropathic bladder (n = 1), chronic bacterial cystitis (n = 3), systemic lupus erythematosus cystitis (n = 2) and normals (n = 6), were investigated. There were significantly more nerve fibres within the sub-urothelial and detrusor muscle layers in chronic interstitial cystitis than there were in normals. Patients with chronic cystitis of other aetiology did not have a significant increase in nerve fibre density within the bladder wall suggesting a specific association between nerve fibre proliferation and interstitial cystitis. Cystolysis is shown to deplete selectively the submucosal nerve plexuses without altering the nerve density within detrusor muscle. This finding explains the desensitisation of the bladder without impairment of detrusor function after this procedure.

Permanent external striated sphincter stents in patients with spinal injuries

Nine patients with complete quadriplegia underwent external striated sphincter stenting with the Wallstent in place of an external striated sphincterotomy. Although suprapubic catheters were placed to provide an outlet should problems develop with the stent, they were successfully removed within 6 weeks in all but 1 patient. Complete bladder emptying with reduced voiding pressures was achieved, together with a significant reduction in the duration of hyper-reflexic contractions. Epithelialisation of the stent was almost complete within 3 months and intermittent catheterisation or endoscopy (and resection) is possible through the stent. Although this is a preliminary report of this new technique, it is hoped that sphincter stenting will provide a rapid, safe and effective method of treating high pressure hyper-reflexia and detrusor sphincter dyssynergia in quadriplegic patients.

Permanently implanted urethral stent for prostatic obstruction in the unfit patient. Preliminary report

We describe the use of a new urethral stent implanted into 12 patients with prostatic outflow obstruction. All were in a high risk group for surgery and 11 were treated successfully, with a follow-up of 1 to 11 months (median 9). The majority of patients were satisfied with the procedure, which provided a quick, safe and effective alternative to conventional surgical treatment. The stent, woven from fine stainless steel in the form of a tubular mesh, was inserted via a delivery device using combined ultrasound and endoscopic control under local anaesthesia. The procedure was well tolerated, the stent becoming covered with epithelium by 6 to 8 months following insertion, yet allowing easy removal within the first 4 to 6 weeks should the need arise. This technique provides a useful alternative to conventional surgical treatment in the high risk patient.

Bladder calculus formation as a complication of the Stamey procedure

Three cases of bladder stone due to a migrated Stamey suture and cuff are reported. In each case peroperative cystoscopy confirmed that the sutures were extravesical. The Stamey cuff subsequently formed a nidus for intravesical stone formation. The mechanism of migration of the cuff, the radiological findings and the operative technique are discussed.

Pre-operative localisation in primary hyperparathyroidism

One hundred and seventy-three patients operated on for primary hyperparathyroidism over a four year period by one experienced surgeon are reviewed. An overall success rate of 98.8% was achieved with information from pre-operative localisation using ultrasound and parathyroid venography with sampling. Parathyroid ultrasound was heavily dependent on the experience of the operator. An experienced ultrasonologist detected 63% of solitary adenomas and correctly localised the site of 82%. Glands were not detected if they were of small size or in an inaccessible site. He identified all those enlarged glands over 0.36 grams in weight that were lying in the usual site. In contrast, inexperienced ultrasonologists had a detection rate of 20%. Parathyroid venography with sampling detected a single site of excess hormone production in the neck of 79% of patients with a single adenoma, and correctly localised the site in 75% of these. The side was correctly predicted for 63% of glands, the level was correctly predicted for 56% and both side and level localisations were correct in 44%. Multi-gland disease was correctly suggested by the experienced ultrasonologist in 56% of cases and by parathyroid venography with sampling in 31% cases.

A twelve-week placebo-controlled study of prazosin in the treatment of prostatic obstruction

Fifty-eight normotensive patients with benign prostatic hyperplasia and maximum urinary flow rates of less than 15 ml/s were randomly assigned to receive a 12-week course of treatment with prazosin or placebo in a double-blind parallel group trial. Prazosin was administered orally in doses of 0.5 mg and then 1 mg twice daily for 4 days each and 2 mg twice daily for the remainder of the trial. Patients on treatment with prazosin had an increased urinary flow rate as compared to placebo with a significant reduction in maximum voiding detrusor pressure and maximum detrusor pressure at peak urinary flow. Although a significant effect on frequency was not demonstrated, standard parameters of detrusor instability were reduced. Investigators' double-blind overall assessment of efficacy significantly favoured the prazosin treatment. Twelve patients were excluded from the final analysis, 8 being withdrawn because of adverse effects, 5 on treatment with prazosin and 3 in the placebo group. Oral prazosin appears to be safe and effective in the long-term treatment of patients with benign prostatic hyperplasia.

Asymptomatic bladder neck incompetence in nulliparous females

This study investigated 29 nulliparous women using the technique of transvaginal ultrasound to assess whether their bladder necks were open or closed at rest. The patients comprised 2 groups: 4 reported occasional episodes of stress incontinence, all of whom had closed bladder necks; the remaining 25 patients were totally asymptomatic. Overall a 21% incidence of an open bladder neck was recorded. It is likely that the true incidence of open bladder necks in young nulliparous women is higher than this, since none of these patients had troublesome stress incontinence. Since women with open bladder necks are more likely to develop stress incontinence if the integrity of the distal sphincter mechanism is compromised by neural damage, antenatal recognition of this problem should provide a contraindication to traumatic vaginal delivery and may in the future reduce the incidence of symptomatic stress incontinence in the population.

Autoradiographic analysis of alpha-adrenoceptors and muscarinic cholinergic receptors in the hyperplastic human prostate

Radioligand receptor binding and autoradiography were used to characterize, localize and compare alpha-1 and alpha-2 adrenoceptors and muscarinic cholinergic receptor populations in human benign prostatic hyperplastic tissue. The binding of selective alpha-1 and alpha-2 ligands, [3H]-prazosin and [3H]-UK 14,304, to homogenates of human central and peripheral prostate was saturable and of high affinity. Scatchard analysis produced an equilibrium dissociation constant (KD) of 0.51 +/- 0.10 nM for alpha-1 adrenoceptors, and 2.34 +/- 0.40 nM for alpha-2 adrenoceptors. The mean densities, Bmax, of alpha-1 and alpha-2 adrenoceptors identified in the human adenomatous prostate were 65.9 +/- 12.9 and 36.1 +/- 7.0 fmoles/mg. protein respectively. Receptor autoradiography was used to examine the distribution of muscarinic cholinergic receptors [( 3H]-QNB), alpha-1 adrenoceptors [( 3H]-prazosin]), and alpha-2 adrenoceptors [( 3H]-rauwolscine) on consecutive sections of benign hyperplastic prostatic tissue. Although both subtypes of adrenoceptor were seen in the stromal component of the hyperplastic prostate, there was a substantial predominance of alpha-1 adrenoceptors. A densitometric computer-assisted analysis was performed on the autoradiographic slides to determine the mean ratio of specific alpha-1: alpha-2 adrenoceptors in the stromal compartment of the hyperplastic tissue. The ratio, expressed as % grain occupancy/unit area, was 3.9 +/- 0.75, which is in agreement with a functional alpha-1 adrenoceptor predominance shown in previous studies. Although sparsely distributed in the stroma, a dense alpha-2 adrenoceptor population was seen in association with blood vessels, and in close proximity to the base of some of the [3H]-QNB-labelled prostatic glandular epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

A new treatment for urethral strictures: a permanently implanted urethral stent

We describe a new urethral stent, originally developed for endovascular use, that we have implanted into 8 patients with urethral strictures. The stent is woven in the form of a tubular mesh from surgical grade stainless steel wire and is self-expanding when released from its small diameter delivery catheter. All patients have been treated successfully with a good caliber urethra visible on urethrography and direct endoscopy, and with improved urine flow rates. Mean followup of these patients is 8 months (range 6 months to 1 year). Urethroscopy had demonstrated complete epithelial covering of the implant at 4 to 6 months. Although the followup is short it seems that this simple technique may offer a lasting treatment for many urethral strictures.

Characterisation of human prostatic adrenoceptors using pharmacology receptor binding and localisation

Benign prostatic enlargement is a common cause of bladder outlet obstruction. Recent work has demonstrated the important role played by the sympathetic nervous system in the control of prostatic muscle tone. Although isometric muscle strip studies and clinical trials have highlighted the influence of alpha-1 adrenoceptors, radioisotope ligand binding studies have demonstrated a relatively increased density of alpha-2 adrenoceptors in the muscle within prostatic tissue, the significance of which is as yet unexplained. Forty patients entered a study using pharmacological muscle strip experiments, radioligand binding assays and receptor autoradiography. Pharmacological data from these studies confirmed that contraction of prostatic muscle is mediated predominantly by alpha-1 adrenoceptor stimulation, with no evidence of significant alpha-2 adrenoceptor or cholinergic mediated effects. Radioligand binding studies confirmed that there is a higher concentration of alpha-1 binding sites as contrasted to alpha-2 within normal prostate, but that this relationship approaches equity in adenomatous prostate. Autoradiographic localisation demonstrated that alpha-1 adrenoceptor binding is predominant within prostatic stroma with only a small component of alpha-2 adrenoceptors in this compartment. This comprehensive study supports the suggestion that prostatic muscular contraction is controlled by the influence of the sympathetic nervous system acting via alpha-1 adrenoceptors. These findings support the therapeutic use of specific alpha-1 adrenoceptor blockade in the management of benign prostatic hyperplasia.

Contemporary flow meters: an assessment of their accuracy and reliability

The accuracy, reliability and cost effectiveness of 5 currently marketed flow meters have been assessed. The mechanics of each meter is briefly described in relation to its accuracy and robustness. The merits and faults of the meters are discussed and the important features of flow measurements that need to be taken into account when making diagnostic interpretations are emphasised.

A new stent for the treatment of urethral strictures. Preliminary report

We describe a new urethral stent which was implanted into 12 patients with urethral strictures. The stent is woven in the form of a tubular mesh from fine stainless steel wire and is self-expanding when released from its small diameter delivery catheter. All patients have been treated successfully, with a good calibre urethra visible on urethrography and direct endoscopy and with improved urine flow rates. The mean follow-up of these patients was 7 months (range 2-13). Urethroscopy demonstrated complete epithelial covering of the implant in 4 to 6 months. Although the follow-up period was short, it seems that this simple technique may offer a lasting treatment for many urethral strictures. A longer follow-up will be necessary to exclude late complications.

Bonney's blue cystitis: a warning

The instillation of diluted Bonney's blue into the bladder during gynaecological operations has been quite common practice over the last 50 years. Bonney's blue is composed of a 1:1 mixture of brilliant green and crystal violet dissolved in ethanol (90%) or industrial methylated spirit. Before insertion into the bladder this solution must be diluted with water to a 0.5% solution. Failure to do this will result in a severe inflammatory reaction within the bladder. The degree of resultant damage depends upon the duration of exposure. Persistent pain is a feature of this condition, although the other symptoms (frequency and urgency) may settle in time. Two cases of chemical cystitis resulting from the use of undiluted Bonney's blue are described to illustrate the possible consequences. Both patients were awarded 6-figure sums as compensation.

The black thyroid: an unusual finding during neck exploration

Black thyroid discolouration has been reported in post-mortem examinations on patients who have previously taken minocycline. The discovery of this phenomenon during neck exploration and a review of the possible mechanism of black thyroid discolouration are discussed in this paper.

Role of subcutaneous apomorphine in parkinsonian voiding dysfunction

Ten patients with Parkinson's disease and urinary symptoms underwent urodynamic assessments before and after subcutaneous administration of the dopamine receptor agonist apomorphine. Voiding efficiency improved after apomorphine injection, with an increase in mean and maximum flow rates in nine patients and reduction in post-micturition residual volume in six. Although the effect on detrusor behaviour was variable, subcutaneous apomorphine may be of use in both the assessment and treatment of voiding dysfunction in patients with Parkinson's disease.

Rigid versus flexible cystoscopy. A controlled trial of patient tolerance

The cost-efficiency and time-saving associated with out-patient flexible cystoscopy have propagated its use nationwide. However, only minimal attention has been paid to the feelings of patients exposed to this physically and emotionally invasive technique. We studied 53 consecutive patients attending for check cystoscopy at the time of their first flexible cystoscopy. Acting as their own historical controls, their feelings about rigid cystoscopy under general anaesthesia and subsequent flexible cystoscopy under local anaesthesia were assessed: 6/53 (11%) preferred rigid cystoscopy under general anaesthesia. The only significant association with their dislike of flexible cystoscopy, was their desire to stay in hospital overnight. It was concluded that with careful counselling and attention to individual needs, the preference for flexible cystoscopy over rigid cystoscopy under general anaesthesia can approach 100%.

Hyperparathyroidism after neck irradiation

A retrospective review of 1550 cases of hyperparathyroidism (HPT) treated surgically over a 30-year period reveals a past history of exposure to neck irradiation in 10 cases (0.7 per cent). The indication for radiotherapy was benign disease in nine and papillary thyroid carcinoma in one case. The mean interval between radiation exposure and the detection of HPT was 32 years (range 3-63 years). Patients treated with radioactive iodine alone developed HPT after a mean of 5 years while the interval for those treated with external beam therapy alone was a mean of 44 years. The parathyroid histology was adenoma in six cases, carcinoma in three cases and nodular hyperplasia in one case. All patients had coincident benign thyroid disease apart from one that had previously had papillary carcinoma and another with follicular carcinoma. Neck irradiation has been shown to confer an increased risk of HPT due to parathyroid adenoma and carcinoma. Radiotherapy for benign disease has generally been abandoned and these cases demonstrate a further contra-indication for the use of neck irradiation.

A new treatment for urethral strictures

A urethral stent, originally developed for endovascular use, was implanted into eight patients with urethral strictures after experimental studies in the canine urethra. The stent is woven in the form of a tubular mesh from surgical grade stainless steel wire and is self-expanding when released from its small-diameter delivery catheter. At follow-up 6 months to 1 year postoperatively (mean 8 months) all had a good calibre urethra. Urethroscopy showed complete epithelial covering of the implant at 4-6 months.

A percutaneous perineal approach for cystoscopy in male dogs

A percutaneous perineal approach is presented as a further technique for rigid cystoscopy in male dogs. The anatomy of the urethra in the male dog prevents rigid cystoscopy by non-surgical means but a fine flexible fibrescope may be used. Perineal urethrotomy and prepubic percutaneous puncture techniques using rigid endoscopes have been described; however, both have possible serious complications. This new procedure allows access for visual examination, biopsy and resection as necessary and appears to have few adverse sequelae.

Prazosin in the treatment of prostatic obstruction. A placebo-controlled study

Eighty patients with prostatic obstruction were entered into a double-blind parallel study of prazosin versus placebo. There were 25 withdrawals or exclusions, leaving 55 patients for analysis. Mean maximum flow rates increased significantly more in patients treated with prazosin than in those treated with placebo (P less than 0.005), but there was no significant reduction in maximum voiding pressure. The mean number of voids, recorded on diary cards, was reduced from an initial 10.0/24 h by 2.1 in the final week, a significantly greater reduction than in the placebo group (P less than 0.01). However, there were no statistically significant changes in the filling cystometrograms. When patients were classified as responders or non-responders in terms of bladder filling, urine flow, bladder emptying, weekly average of voids/24 h and nocturia, the proportion of patients responding to prazosin was significantly greater in all categories except bladder filling and emptying. It was concluded that prazosin at a dose of 2 mg bd is a safe and effective treatment for prostatic obstruction and may be used in patients awaiting surgery and those who are unfit for operation.

Bladder muscle biopsy and urethral sphincter EMG in patients with bladder dysfunction after pelvic surgery

Eleven patients who suffered persistent bladder dysfunction after pelvic surgery have been investigated by needle urethral sphincter electromyography (EMG) and bladder muscle biopsy, and the results compared with those obtained in a series of controls. Individual motor units recorded from the urethral sphincter in patients who had undergone pelvic surgery were strikingly abnormal, suggesting the presence of reinnervation, and the density of detrusor innervation was significantly reduced. However, since reduction in the density of detrusor innervation may occur in circumstances other than peripheral nerve injury, we conclude that urethral sphincter EMG provides the most effective means of assessing damage to vesico-urethral innervation as a result of previous pelvic surgery.

Steroid 5 alpha-reductase deficiency and posterior urethral valves

Posterior urethral valves were seen in a 2-year-old boy who also had steroid 5 alpha-reductase deficiency. This combination has not been reported before and has relevance for the physiology of sexual differentiation.

Micturition disturbance in Parkinson's disease

Ten men with longstanding idiopathic Parkinson's disease (IPD) were investigated by urodynamic and electromyographic methods. The urodynamic studies were repeated after stopping anti-Parkinsonian medication for several hours. All patients showed a difference between the two studies, but the changes were unpredictable. Three patients who had high residual urine volumes in both studies were thought to have prostatic obstruction. EMG analysis showed no evidence of a lower motor neurone lesion affecting the striated urethral sphincter. It was concluded that micturition difficulty in the patient with IPD is due to detrusor hyperreflexia, influenced by the basal ganglia, which is not associated with impaired striated urethral sphincter activity.

16 alpha-Iodo-testosterone: chemical synthesis and evaluation as a potential radiopharmaceutical

The chemical synthesis and characterization, including 1H NMR, of 16 alpha-iodo-androstenedione and 16 alpha-iodo-testosterone are described. Each has been synthesized with 125I and tested in rats in vivo for accumulation in androgen dependent tissues over a 24 hr time course. Neither compound was accumulated in prostate against the blood gradient of normal or 24 hr castrate animals. The metabolism, subcellular distribution and binding of 16 alpha-[125I]iodo-testosterone to protein in prostate has also been examined. By comparison with data obtained after the administration of [3H]testosterone we conclude that the failure of this iodinated androgen to accumulate in androgen dependent tissues arises because of its low binding affinity for receptor protein.