Runoff infiltration, a desktop case study.

The use of sustainable drainage systems (SuDS) or best management practice is becoming increasingly common. However, rather than adopting the preferred 'treatment train' implementation, many developments opt for end-of-pipe control ponds. This paper discusses the use of SUDS in series to form treatment trains and compares their potential performance and effectiveness with end-of-pipe solutions. Land-use, site and catchment characteristics have been used alongside up-to-date guidance, Infoworks CS and MUSIC to determine whole-life-costs, land-take, water quality and quantity for different SuDS combinations. The results presented show that the use of a treatment train allows approaches differing from the traditional use of single SuDS, either source or 'end-of-pipe', to be proposed to treat and attenuate runoff. The outcome is a more flexible solution where the footprint allocated to SUDS, costs and water quality can be managed differently to fully meet stakeholder objectives.

Chronic AT1 receptor blockade and angiotensin-converting enzyme (ACE) inhibition in (CHF 146) cardiomyopathic hamsters: effects on cardiac hypertrophy and survival.

OBJECTIVE: We have reported that angiotensin II AT1 receptors are upregulated and that there are no AT2 receptors in the ventricles of cardiomyopathic hamsters. Since the upregulation was present even when no histological lesions were detectable, these results suggested that angiotensin II plays a role in the genesis/maintenance of this pathology. A survival study was conducted to compare the effects of an angiotensin II AT1 receptor antagonist, losartan (L), to those of a placebo (P). Since the angiotensin-converting enzyme (ACE) inhibitor quinapril (Q) has been shown to have beneficial effects in this animal model, a Q group was included. METHODS: Male Syrian cardiomyopathic hamsters (CHF 146, n = 360) were orally administered P, low- (30 mg/kg/day) or high-dose (100 mg/kg/day) L, or Q (100 mg/kg/day), starting at day 50 of life. Inbred control hamsters (CHF 148, n = 180) were treated with P or L (100 mg/kg/day) as controls. Animals were sacrificed at intervals to evaluate cardiac hypertrophy. Kaplan-Meier analysis was performed to assess differences in survival. RESULTS: High-dose L had no effects on the survival of control hamsters. There was an unexpected dose-dependent decrease in the survival of cardiomyopathics treated with L (low-dose, P = 0.14; high-dose, P = 0.0015) compared to an increase with Q (P = 0.0003). Cardiac hypertrophy compared to P was increased with L but significantly decreased with Q in cardiomyopathics. CONCLUSIONS: In this model, losartan did not improve survival compared to placebo and quinapril and, if anything, increased mortality. Our results suggest that AT1 receptor antagonists and ACE inhibitors are not necessarily equivalent or interchangeable in terms of their effects on cardiac hypertrophy and survival in selected progressive heart failure models.

Angiotensin II receptor expression in the conduction system and arterial duct of neonatal and adult rat hearts.

Paralleling the classic circulating system, recent evidence has demonstrated the presence of a cardiac renin-angiotensin system, as well as the synthesis of angiotensin II in the heart. Two receptors for angiotensin II have been identified and classified as AT1 and AT2. The proportions of these receptor subtypes vary with the tissues, species and stage of development. From the results of other studies, it might be generalized that the expression of angiotensin II receptors and the proportion of AT2 receptor subtype are much higher in fetal and neonatal tissues than in the same tissues from an adult. The aim of this study was to specifically evaluate the AT1/AT2 ratio in the neonatal and adult conduction systems of rat hearts by means of quantitative autoradiogrphy. In the neonatal hearts, angiotensin II binding sites were highly concentrated in the vasculature, arterial duct, and conduction system, whereas their concentrations were barely detectable in the myocardium. Incubation with selective angiotensin II receptor ligands (losartan and CGP 42112) revealed that AT2 was the major subtype in vasculature (86 +/- 3%) and conduction system (73 +/- 4%). In the adult conduction system, the total expression of angiotensin II receptors was greatly reduced meanwhile the AT1 receptors represented the major proportion of the binding sites (80 +/- 3%). Our results demonstrated that the pattern of angiotensin II receptor expression in the conduction system of the rat heart is developmentally regulated. We suggest, as others have already, that the renin-angiotensin system plays a role during the early stage of cardiac development.

Downregulation of cardiac AT1-receptor expression and angiotensin II concentrations after long-term blockade of the renin-angiotensin system in cardiomyopathic hamsters.

We monitored cardiac angiotensin II concentration and AT1-receptor density after long-term blockade of the renin-angiotensin system in inbred control hamsters treated with placebo or losartan (100 mg/kg/day) and cardiomyopathic hamsters treated with placebo, low-(30 mg/kg/day), or high-dose (100 mg/kg/day) losartan or quinapril (100 mg/kg/day). All treatments were started at age 50 days. Angiotensin II-receptor density and affinity were measured by radioligand-binding assays, and ventricular angiotensin II concentration was determined by radioimmunoassay. After 125 and 275 days of treatment, both doses of losartan significantly reduced AT1-receptor density, whereas quinapril had no effect. The administration of both drugs resulted in significant reductions in ventricular angiotensin II concentration. The prolonged administration of losartan was associated with an increase in cardiac hypertrophy, suggesting that angiotensin II signaling is not directly involved or at least does not play a major role in the remodeling process observed in cardiomyopathic hamsters.