This section contains papers from Japan, Austria, the UK, and joint papers from France, Denmark, Switzerland, Australia and the USA. A wide variety of lower urinary tract topics is covered, from BPH to overactive bladder and urodynamic stress incontinence. OBJECTIVE To verify the efficacy and safety of the new α1A‐adrenoceptor‐selective antagonist silodosin compared with tamsulosin and placebo in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). PATIENTS AND METHODS This randomized, double‐blind, placebo‐controlled study was conducted at 88 centres in Japan. Men aged ≥50 years with an International Prostate Symptom Score (IPSS) of ≥8, a quality‐of‐life (QoL) score of ≥3, a maximum urinary flow rate (Qmax) of <15 mL/s, a prostate volume of ≥20 mL and a postvoid residual urine volume of <100 mL were eligible for enrolment. Patients were randomized to receive silodosin 4 mg twice daily, tamsulosin 0.2 mg once daily, or placebo, for 12 weeks. The primary endpoint was the change in IPSS from baseline. Safety was assessed by adverse events, physical examination, vital signs and laboratory tests. RESULTS In all, 457 patients were randomized (silodosin 176, tamsulosin 192 and placebo 89). The change in the total IPSS from baseline in the silodosin, tamsulosin and placebo groups was −8.3, −6.8 and −5.3, respectively. There was a significant decrease in the IPSS vs placebo in the silodosin group from 1 week. In the early‐stage comparison, silodosin showed a significant decrease in IPSS vs tamsulosin at 2 weeks. The change in QoL from baseline was −1.7, −1.4 and −1.1 in the silodosin, tamsulosin and placebo groups, respectively; silodosin showed a significant improvement in the QoL score vs placebo. In the subgroup of patients with severe symptoms (IPSS ≥20) silodosin also gave a significantly better improvement than placebo (−12.4 vs −8.7). The incidence rates of adverse events and drug‐related adverse events were, respectively, 88.6%, 82.3% and 71.6% and 69.7%, 47.4% and 36.4%, respectively. The most common adverse event in the silodosin group was abnormal ejaculation, which occurred more often in the silodosin than in the tamsulosin group (22.3% vs 1.6%). However, only five men (2.9%) discontinued treatment for abnormal ejaculation. CONCLUSION Silodosin was generally effective in the absence of obtrusive side‐effects. This study suggests that silodosin is clinically useful for treating LUTS associated with BPH.

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1 There are at least three cxl-adrenoceptor subtypes, cxla, alb and ald, in human tissues. Using an RNase protection assay, we have now determined the amount of each subtype mRNA in human prostatic tissue, for both benign prostatic hypertrophy (BPH) and non-BPH. In all tissue samples examined, the predominant subtype mRNA was ala. The total abundance of al-adrenoceptor mRNA in BPH samples was over six times that in non-BPH samples. This increase was mostly accounted for by ala, which was almost nine times as abundant in BPH samples as in non-BPH samples. The abundance of alb was almost the same between BPH and non-BPH samples, and the abundance of ald in BPH samples was about three times that in non-BPH samples. The ratio of the numbers of the subtype mRNAs, ala: alb: ald, was 85:1:14 in BPH samples and 63 :6:31 in non-BPH samples. 2 In situ hybridization studies showed no significant differences in the tissue localization of Lxladrenoceptor subtype mRNAs between BPH and non-BPH samples. atla and acld were clearly detected in the interstitium of the prostate, where axla was stained more intensely than Lxld, and the positive sites were primarily smooth muscle cells. In contrast, alb staining was very faint. 3 This increase in mRNA abundance may be directly related to the contraction of prostatic tissue that leads to obstruction of the urinary tract in BPH patients. Specifically, our data suggest that increased expression of the Lxla subtype may be primarily responsible for the contraction of the prostate.

1 Two restriction fragment length polymorphisms of the human ala-adrenoceptor gene digested with PstI restriction enzyme exist; the nucleotide change causes the substitution of C residue for T at nucleotide 1441, thereby Arg492 to Cys492 transition, which might confer an additional putative palmitoylation site in the carboxy-terminal segment of the Xla-adrenoceptor. In the present study, we compared their pharmacological properties and examined whether this aa-adrenoceptor polymorphism is associated with benign prostatic hypertrophy (BPH).2 The frequency of ala-adrenoceptor polymorphism was not differently distributed between patients with benign prostatic hypertrophy (BPH) and normal subjects in Japan; thus, the relative frequencies of the C and T alleles were 0.90: 0.10 in normal male subjects (n=45) and 0.87: 0.13 in BPH patients (n=222), respectively. However, the frequency distribution of this polymorphism was significantly different between the Japanese and U.S. populations; thus, C and T alleles were 0.34 and 0.66 in U.S. populations.