Role of ATP and related purines in inhibitory neurotransmission to the pig urinary bladder neck

Background and purpose:

As adenosine 5′-triphosphate (ATP) is one of the inhibitory mediators of the bladder outflow region, this study investigates the possible release of ATP or related purines in response to electrical field stimulation (EFS) and the purinoceptor(s) involved in nerve-mediated relaxations of the pig urinary bladder neck.

Experimental approach:

Urothelium-denuded and intact phenylephrine-precontracted strips were mounted in organ baths containing physiological saline solution at 37°C and gassed with 95% O₂ and 5% CO₂ for isometric force recordings.

Key results:

EFS, in the presence of atropine, guanethidine and N^G-nitro-L-arginine, and exogenous purines, produced frequency- and concentration-dependent relaxations respectively. Adenosine 5′-diphosphate (ADP) and adenosine were more potent than ATP in producing relaxation, while uridine 5′-triphosphate, uridine 5′-diphosphate and α,β-methylene ATP were less effective. The non-selective P2 antagonist suramin, and the P2Y₁ and P1 receptor blockers 2′-deoxy-N6-methyladenosine 3′,5′-bisphosphate tetrasodium and 8-(p-sulphophenyl)theophylline, respectively, inhibited the responses to EFS and ATP. The P1 agonist''s potency was: 5′-N-ethylcarboxamidoadenosine (NECA)>4-2[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzene propanoic acid hydrochloride>2-chloro-N⁶-cyclopentyladenosine>-2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-b-D-ribofuranuronamide = adenosine. 4-(-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl) phenol, an A_2A antagonist, reduced the relaxations to EFS, adenosine and NECA. In urothelium-intact samples, relaxations to EFS and purines were smaller than in urothelium-denuded preparations. Neuronal voltage-gated Na⁺ channels blockade failed to modify ATP relaxations. At basal tension, EFS- and ATP-induced contractions were resistant to desensitization or blockade of P2X₁ and P2X₃ receptors.

Conclusions and implications:

ATP is involved in the non-adrenergic, non-cholinergic, non-nitrergic inhibitory neurotransmission in the pig bladder neck, producing relaxation largely through muscle A_2A receptors after breakdown to adenosine, and P2Y₁ receptors after breakdown to ADP. Antagonists of these receptors may be useful for urinary incontinence treatment produced by intrinsic sphincteric deficiency.     

One year open-label safety and efficacy trial with rotigotine transdermal patch in moderate to severe idiopathic restless legs syndrome

BackgroundLong-term efficacy and tolerability data are not yet available for patch formulations of dopamine agonists in restless legs syndrome.MethodsEfficacy and safety of rotigotine (0.5–4 mg/24 h), formulated as a once-daily transdermal system (patch), were investigated in an open extension (SP710) of a preceding 6-week placebo-controlled trial (SP709, 341 randomized patients) in patients with idiopathic restless legs syndrome. For efficacy assessment the international RLS severity scale (IRLS), the RLS-6 scales, the clinical global impressions (CGI) and the QoL-RLS questionnaire were administered. In addition, long-term tolerability and safety were assessed.ResultsOf 310 patients who finished the controlled trial, 295 (mean age 58 ± 10 years, 66% females) with a mean IRLS score of 27.8 ± 5.9 at baseline of SP709 were included. We report results after one year of this ongoing long-term trial. Two hundred twenty patients (retention rate = 74.6%) completed the 12-month follow-up period. The mean daily dose was 2.8 ± 1.2 mg/24 h with 4 mg/24 h (40.6%) being the most frequently applied dose; 14.8% were sufficiently treated with 0.5 or 1.0 mg/24 h. The IRLS total score improved by −17.4 ± 9.9 points between baseline and end of Year 1 (p < 0.001). The other measures of severity, sleep satisfaction and quality of life supported the efficacy of rotigotine (p < 0.001 for pre-post-comparisons of all efficacy variables). The tolerability was described as “good” or “very good” by 80.3% of all patients. The most common adverse events were application site reactions (40.0%), which led to withdrawal in 13.2%. Further relatively frequent adverse events were nausea (9.5%) and fatigue (6.4%). Two drug-related serious adverse events, nausea and syncope, required hospitalization. Symptoms of augmentation were not reported by the patients.ConclusionRotigotine provided a stable, clinically relevant improvement in all efficacy measures throughout one year of maintenance therapy. The transdermal patch was safe and generally well tolerated by the majority of patients. Comparable to any transdermal therapy, application site reactions were the main treatment complication.     

Efficacy of rotigotine for treatment of moderate-to-severe restless legs syndrome: a randomised, double-blind, placebo-controlled trial

BACKGROUND: Continuous administration of a dopamine agonist could be used to treat patients with restless legs syndrome. Our aim was to investigate the efficacy of transdermal rotigotine in the treatment of idiopathic restless legs syndrome. METHODS: In this randomised, double-blind, placebo-controlled trial, 458 patients with moderate-to-severe idiopathic restless legs syndrome (average baseline International Restless Legs Syndrome Study Group severity rating scale [IRLS] sum score of 28.1) were randomly assigned to receive transdermal rotigotine 1 mg over 24 h (n=115), 2 mg over 24 h (n=112), or 3 mg over 24 h (n=114), or to receive placebo (n=117). Study medication was delivered via patches, applied once a day for 6 months. Randomisation was done with a computer-generated randomisation list, stratified by centre. Primary efficacy outcomes were absolute change from baseline to end of maintenance in IRLS sum score and in the clinical global impressions (CGI) item 1 score, assessed by analysis of covariance in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT00136045. FINDINGS: Efficacy analyses were done on 112 patients in the 1 mg group, 109 in the 2 mg group, 112 in the 3 mg group, and 114 in the placebo group. Mean change in IRLS sum score from baseline at the end of the maintenance phase was -13.7 (SE 0.9) in the 1 mg group, -16.2 (0.9) in the 2 mg group, -16.8 (0.9) in the 3 mg group, and -8.6 (0.9) in the placebo group (p<0.0001 for treatment difference vs placebo with each dose). Mean change in CGI item 1 score from baseline at the end of the maintenance phase was -2.09 (0.14) in the 1 mg group, -2.41 (0.14) in the 2 mg group, -2.55 (0.14) in the 3 mg group, and -1.34 (0.14) in the placebo group (p<0.0001 for treatment difference vs placebo with each dose). Skin reactions, mostly mild or moderate, were seen in 145 (43%) of 341 patients who received rotigotine and in two (2%) of 117 who received placebo. Ten patients had serious adverse event that were deemed to be related to rotigotine: elevation of liver enzymes (one patient), worsening of tinnitus (one patient), non-response to anticoagulation (one patient), electrocardiogram changes (one patient), and application-site reactions (six patients). No admissions to hospital were needed for the application-site reactions, and they all resolved within a short time of patch removal without any other therapeutic intervention. The rate of typical dopaminergic side-effects in patients who received rotigotine was low; no signs of augmentation were noted. INTERPRETATION: 24 h transdermal delivery of low-dose rotigotine could be used to relieve the night-time and daytime symptoms of restless legs syndrome. FUNDING: Schwarz Biosciences.     

Arterial stiffness: determinants and relationship to the metabolic syndrome

This study aimed to investigate independent determinants of arterial stiffness and evaluate the association of arterial stiffness with the presence of metabolic syndrome (MS). Demographic characteristics, hemodynamic parameters, and cardiovascular (CV) risk factors were assessed in Greek food industry employees with no history of diabetes or CV disease in order to isolate multiple correlates of arterial stiffness as assessed by pulse wave velocity (PWV). Subsequently, logistic regression analysis was performed using as end point the presence of MS, defined according to the National Cholesterol Education Program. Data from 424 participants (mean age 45.3 -/+ 15.5 years, 298 [70.3%] males, average PWV 8.5 -/+ 3.6 m/s) were analyzed. PWV was higher in men (8.8 -/+ 3.1 m/s) compared to women (7.7 -/+ 2.9 m/s, p < 0.01). Age, systolic blood pressure, and heart rate were isolated as multivariate determinants of PWV (adjusted R2 0.511 [p < 0.0001] in men and 0.538 [p < 0.0001] in women). The overall prevalence of the MS was 14.6%, being similar in both genders. Four variables were shown to be independent predictors of the presence of MS: waist circumference >102 cm (men)/88 cm (women) (OR 8.6, [95% CI 2.8, 20.6], p < 0.001), insulin resistance (homeostasis model assessment >4) (6.3, [2.1, 17.6], p < 0.001), total cholesterol >240 mg/dL (5.5, [1.7, 12.4], p < 0.01), PWV >9 m/s (4.1, [1.5, 9.9], p < 0.01). High PWV, which was found to be mostly determined by advanced age, elevated systolic BP, and accelerated heart rate, appeared to exhibit a strong independent association with the presence of MS together with adiposity and insulin resistance. This index should be considered as a useful marker for CV risk stratification.     

Influence of body mass index on prostate-specific antigen failure after androgen suppression and radiation therapy for localized prostate cancer

BACKGROUND: Increasing body mass index (BMI) is associated with shorter time to prostate-specific antigen (PSA) failure after radical prostatectomy. Whether BMI is associated with time to PSA failure was investigated in men treated with androgen suppression therapy (AST) and radiation therapy (RT) for clinically localized prostate cancer. METHODS: The observational prospective cohort study consisted of 102 men with clinically localized prostate cancer who received 70 Gy RT with 6 months of AST on a single arm of a randomized trial between December 1995 and April 2001. Height and weight data were available at baseline for 99 (97%) of the men, from which BMI was calculated. Adjusting for age (continuous) and known prognostic factors including PSA level (continuous), Gleason score, and T-category, Cox regression analyses were performed to analyze whether BMI (continuous) was associated with time to PSA failure (PSA >1.0 ng/mL and increasing >0.2 ng/mL on 2 consecutive visits). RESULTS: Median age and median BMI (interquartile range [IQR]) at baseline was 72 (69.1-74.7) years and 27.4 (24.8-30.7) kg/m,(2) respectively. In addition to an increasing PSA level (P = .006) and Gleason 8-10 cancer (P = .024), after a median follow-up (IQR) of 6.9 (5.6-8.5) years, an increasing BMI was also significantly associated with a shorter time to PSA failure (adjusted hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01-1.19; P = .026) after RT and AST. CONCLUSIONS: After adjusting for known prognostic factors, baseline BMI is significantly associated with time to PSA failure after RT and AST for men with clinically localized prostate cancer. Further study is warranted to assess the impact of an increasing BMI after AST administration on PSA failure, prostate cancer-specific, and all-cause mortality.     

合欢皮中新皂甙的结构鉴定

从合欢皮(Albizziae cortex)的95%乙醇提取物的正丁醇萃取部分中分离得到3个新的三萜皂甙,用化学方法及¹H-和¹³C-NMR,DEPT,COSY,TOCSY,HMQC-COSY,HMQC-TOCSY,HMBC,NOESY等波谱方法鉴定其结构为:I(1个三萜,9个糖,2个单萜),命名为合欢皂甙(julibroside)J₁;II(1个三萜,8个糖,2个单萜),命名为合欢皂甙J_{2;II(1个三萜,9个糖,2个单萜),命名为合欢皂甙J3。}