Jon Cartledge

Nitric oxide-mediated corpus cavernosal smooth muscle relaxation is impaired in ageing and diabetes

Objective To examine nitric‐oxide (NO)‐mediated relaxation in cavernosal smooth muscle in a rat model of diabetes, as previous experiments showed that HbA1c (an isoform of glycosylated haemoglobin and a marker of long‐term diabetic control) impaired NO‐mediated relaxation of normal corpus cavernosal tissue through the generation of superoxide anions.

Advanced glycation end-products are responsible for the impairment of corpus cavernosal smooth muscle relaxation seen in diabetes.

Objective To determine if advanced glycation end‐products (AGEs) are responsible for the lower neuronal and endothelial‐derived nitric oxide (NO)‐mediated relaxation of corpus cavernosum in tissue in diabetic rats than in control rats.

Radiofrequency ablation (RFA) of renal cell carcinoma (RCC): experience in 200 tumours

To evaluate our clinical experience with percutaneous image‐guided radiofrequency ablation (RFA) of 200 renal tumours in a large tertiary referral university institution.

Impairment of corpus cavernosal smooth muscle relaxation by glycosylated human haemoglobin.

Objective To examine the effect of HbA1c, an isoform of glycosylated haemoglobin (GHb, a product of non‐enzymatic reactions between elevated blood glucose and haemoglobin), on nitric oxide‐mediated corpus cavernosal smooth muscle relaxation, and to categorize the mechanisms involved.

A randomized double‐blind placebo‐controlled crossover trial of the efficacy of l‐arginine in the treatment of interstitial cystitis

Objectives To determine, in a double‐blind placebo‐controlled crossover study, whether l‐arginine improves the symptoms of interstitial cystitis (IC), a chronic condition in which nitric oxide (NO) may be important, as previous open pilot studies suggested that l‐arginine reduced the pain and frequency associated with IC.

Initial Experience with the Resonance Metallic Stent for Antegrade Ureteric Stenting

Background and purposeWe describe our initial experience with a new metallic ureteric stent which has been designed to provide long-term urinary drainage in patients with malignant ureteric strictures. The aim is to achieve longer primary patency rates than conventional polyurethane ureteric stents, where encrustation and compression by malignant masses limit primary patency. The Resonance metallic double-pigtail ureteric stent (Cook, Ireland) is constructed from coiled wire spirals of a corrosion-resistant alloy designed to minimize tissue in-growth and resist encrustation, and the manufacturer recommends interval stent change at 12 months.MethodsSeventeen Resonance stents were inserted via an antegrade approach into 15 patients between December 2004 and March 2006. The causes of ureteric obstruction were malignancies of the bladder (n = 4), colon (n = 3), gynecologic (n = 5), and others (n = 3).ResultsOne patient had the stent changed after 12 months, and 3 patients had their stents changed at 6 months. These stents were draining adequately with minimal encrustation. Four patients are still alive with functioning stents in situ for 2–10 months. Seven patients died with functioning stents in place (follow-up periods of 1 week to 8 months). Three stents failed from the outset due to bulky pelvic malignancy resulting in high intravesical pressure, as occurs with conventional plastic stents.ConclusionOur initial experience with the Resonance metallic ureteric stent indicates that it may provide adequate long-term urinary drainage (up to 12 months) in patients with malignant ureteric obstruction but without significantly bulky pelvic disease. This obviates the need for regular stent changes and would offer significant benefit for these patients with limited life expectancy.

The role of nitric oxide in penile erection

The functional state of the penis, flaccid or erect is governed by smooth muscle tone. Sympathetic contractile factors maintain flaccidity whilst parasympathetic factors induce smooth muscle relaxation and erection. It is generally accepted that nitric oxide (NO) is the principal agent responsible for relaxation of penile smooth muscle. NO is derived from two principal sources: directly from non-adrenergic non-cholinergic parasympathetic nerves and indirectly from the endothelium lining cavernosal sinusoids and blood vessels in response to cholinergic stimulation. The generation of NO from L-arginine is catalysed by nitric oxide synthase (NOS). There has been controversy over the relative prevalence of endothelial or neuronal NOS within the penis of different animal species. This review examines the role of NO in the penis in detail. Established and new treatments for erectile dysfunction whose effects are mediated via manipulation of the NO pathway are also described.

Challenge of percutaneous nephrolithotomy in patients with spinal neuropathy

Objective:  To assess the technical difficulties, associated complications and stone clearance rates in patients with spinal neuropathy undergoing percutaneous nephrolithotomy.

Differences in side-effect duration and related bother levels between phosphodiesterase type 5 inhibitors

To assess whether the longer half‐life of tadalafil is associated with longer lasting or more severe side‐effects than the other phosphodiesterase type 5 inhibitors (PDE‐5Is), as clinical trials have shown that the efficacy and safety of the three available are similar, but tadalafil has a half‐life four times longer than the other two drugs.

The efficacy of a range of contact media as coupling agents in extracorporeal shockwave lithotripsy.

Objective To determine if the nature of the coupling agent normally used between the lithotripter and the patient affects the stone fragmentation rate during extracorporeal shock wave lithotripsy.