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Active Control (active + control)
Selected AbstractsActive Control of Epithelial Cell-Density Gradients Grown Along the Channel of an Organic Electrochemical TransistorADVANCED MATERIALS, Issue 43 2009Maria H. Bolin Complex patterning of the extracellular matrix, cells, and tissues under in situ electronic control is the aim of the technique presented here. The distribution of epithelial cells along the channel of an organic electrochemical transistor is shown to be actively controlled by the gate and drain voltages, as electrochemical gradients are formed along the transistor channel when the device is biased.. [source] Active control of FGM shells subjected to a temperature gradient via piezoelectric sensor/actuator patchesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2002K. M. Liew Abstract A generic static and dynamic finite element formulation is derived for the modelling and control of piezoelectric shell laminates under coupled displacement, temperature and electric potential fields. The base shell is of functionally graded material (FGM) type, which consists of combined ceramic,metal materials with different mixing ratios of the ceramic and metal constituents. A multi-input,multi-output (MIMO) system is applied to provide active feedback control of the laminated shell using self-monitoring sensors and self-controlling actuators through a close loop. Numerical studies clearly show the influence of the positional configurations of sensor/actuator pairs on the effectiveness of static and dynamic control for the shell laminates. The effects of the constituent volume fractions on the static and dynamic responses of the shell laminate are also elucidated. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effect of tabs on impinging heat transferHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2001Munehiko Hiwada Abstract The present work experimentally investigates the effect of vortex generators, in the form of small tabs projecting normally into the flow at the nozzle exit, on the fluid flow and heat transfer characteristics of an axisymmetric impinging air jet in the subcritical Reynolds number range. With this comes the expectation of a large eddy structure variation and the possibility of active control. Local heat transfer and static pressure were measured on a target plate for a round air jet issuing from a circular nozzle with rectangular tabs whose numbers and lengths changed at a constant nozzle-to-plate gap (L/d = 8) and jet Reynolds number (Re = 34,000). The main results are the following: When two tabs were set at the exit of the circular nozzle, Cpw and Nu profiles flatten in the direction of the tab setting. In the case of three tabs, however, among both Cpw and Nu profiles a concentric profile is found, as well as in the case without any tabs. © 2001 Scripta Technica, Heat Trans Asian Res, 30(7): 561,570, 2001 [source] Lack of effects between rupatadine 10,mg and placebo on actual driving performance of healthy volunteersHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 5 2007Eric Vuurman Abstract Introduction Rupatadine fumarate is a potent, selective, histamine H1 -receptor antagonist and PAF inhibitor with demonstrated efficacy for the relief of allergic rhinitis. Rupatadine does not easily cross the blood,brain barrier and is believed to be non-sedating at therapeutic doses. Consequently, rupatadine should show no impairment on car driving. Objective This study compared the acute effects of rupatadine, relative to placebo and hydroxyzine (as an active control), on healthy subjects' driving performance. Methods Twenty subjects received a single dose of rupatadine 10,mg, hydroxyzine 50,mg, or placebo in each period of this randomized, double-blind, three-way crossover study. Two hours postdosing, subjects operated a specially instrumented vehicle in tests designed to measure their driving ability. Before and after the driving tests ratings of sedation were recorded. Results There was no significant difference between rupatadine and placebo in the primary outcome variable: standard deviation of lateral position (SDLP); however, hydroxyzine treatment significantly increased SDLP (p,<,0.001 for both comparisons). Objective (Stanford sleepiness scale) and subjective sedation ratings (Visual Analogue Scales) showed similar results: subjects reported negative effects after hydroxyzine but not after rupatadine. Conclusion Rupatadine 10,mg is not sedating and does not impair driving performance. Copyright © 2007 John Wiley & Sons, Ltd. [source] Practical implementation of multichannel adaptive filters based on FTF and AP algorithms for active controlINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2-3 2005Alberto González Abstract In this paper, multichannel affine projection (AP) algorithms and fast transversal filters (FTF) are introduced for active noise control. A comparative practical study of the mentioned algorithms with the filtered-X LMS (F-XLMS) and the recursive least squares (RLS) is presented for multichannel systems. This study is based on simulations using real data and is mainly focused on: their computational cost and memory load, their convergence properties, their stability and their ability to create quiet zones around listener ears. Simulations show that algorithms based on FTF exhibit a good trade-off between computational cost and convergence speed. On the other hand, those based on RLS are slightly faster but they present higher computational load and stability problems in their practical implementation. It has also been observed that algorithms based on low order AP algorithms present less computational cost than the FTF-based ones but a slightly slower convergence speed. Therefore these algorithms show a desirable behaviour and versatility for practical applications. Finally, results obtained in a real-time multichannel system validate the use of AP algorithms in practical applications as an alternative to the classical multichannel F-XLMS since they provide meaningful attenuation levels, lower convergence time and similar computational cost. Additionally, as simulations indicated, AP algorithm performance can be easily improved increasing its projection order and using fast versions. Copyright © 2004 John Wiley & Sons, Ltd. [source] Peeling Back the Layers: Controlled Erosion and Triggered Disassembly of Multilayered Polyelectrolyte Thin Films,ADVANCED MATERIALS, Issue 23 2007M. Lynn Abstract Methods for the layer-by-layer deposition of oppositely charged polymers on surfaces can be used to assemble thin multilayered films using a broad range of natural, synthetic, and biologically relevant materials. These methods also permit precise, nanometer-scale control over the compositions and internal structures of multicomponent assemblies. Provided that the individual components of these materials are selected or designed appropriately, these methods provide tantalizing new opportunities to design thin films and coatings that provide spatial, temporal, or active control over the release of one or several different agents from surfaces. The last two years have seen a significant increase in reports describing the development of new chemical, physical, and biomolecular approaches to the controlled erosion, triggered disassembly, or general deconstruction of multilayered polymer films. In this Progress Report, we highlight recent work from our laboratory and several other groups toward the design of ultrathin multilayered assemblies that i),permit broad, tunable, and sophisticated control over film erosion, and ii),provide new opportunities for the localized release of macromolecular therapeutics, such as DNA and proteins, from surfaces. [source] Cost-Effectiveness of Preventive Occupational Therapy for Independent-Living Older AdultsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2002Joel Hay PhD OBJECTIVES: To evaluate the cost-effectiveness of a 9-month preventive occupational therapy (OT) program in the Well-Elderly Study: a randomized trial in independent-living older adults that found significant health, function, and quality of life benefits attributable to preventive OT. DESIGN: A randomized trial. SETTING: Two government-subsidized apartment complexes. PARTICIPANTS: One hundred sixty-three culturally diverse volunteers aged 60 and older. INTERVENTION: An OT group, a social activity group (active control), and a nontreatment group (passive control). MEASUREMENTS: Use of healthcare services was determined by telephone interview during and after the treatment phase. A conversion algorithm was applied to the RAND 36-item Short Form Health Survey to derive a preference-based health-related quality of life index, quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio for preventive OT relative to the combined control group. RESULTS: Costs for the 9-month OT program averaged $548 per subject. Postintervention healthcare costs were lower for the OT group ($967) than for the active control group ($1,726), the passive control group ($3,334), or a combination of the control groups ($2,593). The quality of life index showed a 4.5% QALY differential (OT vs combined control), P < .001. The cost per QALY estimates for the OT group was $10,666 (95% confidence interval = $6,747,$25,430). For the passive and active control groups, the corresponding costs per QALY were $13,784 and $7,820, respectively. CONCLUSION: In this study, preventive OT demonstrated cost-effectiveness in conjunction with a trend toward decreased medical expenditures. [source] Item Selection in Computerized Adaptive Testing: Should More Discriminating Items be Used First?JOURNAL OF EDUCATIONAL MEASUREMENT, Issue 3 2001Kit-Tai Hau During computerized adaptive testing (CAT), items are selected continuously according to the test-taker's estimated ability. The traditional method of attaining the highest efficiency in ability estimation is to select items of maximum Fisher information at the currently estimated ability. Test security has become a problem because high-discrimination items are more likely to be selected and become overexposed. So, there seems to be a tradeoff between high efficiency in ability estimations and balanced usage of items. This series of four studies with simulated data addressed the dilemma by focusing on the notion of whether more or less discriminating items should be used first in CAT. The first study demonstrated that the common maximum information method with Sympson and Hetter (1985) control resulted in the use of more discriminating items first. The remaining studies showed that using items in the reverse order (i.e., less discriminating items first), as described in Chang and Ying's (1999) stratified method had potential advantages: (a) a more balanced item usage and (b) a relatively stable resultant item pool structure with easy and inexpensive management. This stratified method may have ability-estimation efficiency better than or close to that of other methods, particularly for operational item pools when retired items cannot be totally replenished with similar highly discriminating items. It is argued that the judicious selection of items, as in the stratified method, is a more active control of item exposure, which can successfully even out the usage of all items. [source] Development of the swimbladder and its innervation in the zebrafish, Danio rerioJOURNAL OF MORPHOLOGY, Issue 11 2007G.N. Robertson Abstract Many teleosts including zebrafish, Danio rerio, actively regulate buoyancy with a gas-filled swimbladder, the volume of which is controlled by autonomic reflexes acting on vascular, muscular, and secretory effectors. In this study, we investigated the morphological development of the zebrafish swimbladder together with its effectors and innervation. The swimbladder first formed as a single chamber, which inflated at 1,3 days posthatching (dph), 3.5,4 mm body length. Lateral nerves were already present as demonstrated by the antibody zn-12, and blood vessels had formed in parallel on the cranial aspect to supply blood to anastomotic capillary loops as demonstrated by Tie-2 antibody staining. Neuropeptide Y-(NPY-) like immunoreactive (LIR) fibers appeared early in the single-chambered stage, and vasoactive intestinal polypeptide (VIP)-LIR fibers and cell bodies developed by 10 dph (5 mm). By 18 dph (6 mm), the anterior chamber formed by evagination from the cranial end of the original chamber; both chambers then enlarged with the ductus communicans forming a constriction between them. The parallel blood vessels developed into an arteriovenous rete on the cranial aspect of the posterior chamber and this region was innervated by zn-12-reactive fibers. Tyrosine hydroxylase- (TH-), NPY-, and VIP-LIR fibers also innervated this area and the lateral posterior chamber. Innervation of the early anterior chamber was also demonstrated by VIP-LIR fibers. By 25,30 dph (8,9 mm), a band of smooth muscle formed in the lateral wall of the posterior chamber. Although gas in the swimbladder increased buoyancy of young larvae just after first inflation, our results suggest that active control of the swimbladder may not occur until after the formation of the two chambers and subsequent development and maturation of vasculature, musculature and innervation of these structures at about 28,30 dph. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Chlorophenol dehalogenation in a magnetically stabilized fluidized bed reactorAICHE JOURNAL, Issue 3 2006Lisa J. Graham Abstract Aromatic halocarbons are often present in contaminated aquifers, surface waters, wastewater streams, soils, and hazardous wastes. The dehalogenation of p-chlorophenol as a model compound in both the aqueous phase and in slurries of contaminated solids using a magnetically stabilized fluidized bed (MSFB) reactor is discussed. Composite palladium-iron (Pd/Fe) media are employed as both catalyst and sacrificial reactant for the reductive dechlorination of p-chlorophenol. Calcium alginate beads impregnated with Pd/Fe granules are fluidized in a recirculating aqueous stream containing either dissolved p-chlorophenol or a slurry of soil contaminated with this chlorocarbon. Magnetic stabilization of the fluidized bed allows substantially higher rates of mass transfer than would otherwise be achievable, and allows circulation of contaminated solids while fluidization media are retained. Anoxic conditions are sustained under a nitrogen purge and the solution pH of 5.8 is maintained by active control to minimize surface fouling by hydroxides, and to minimize mass-transfer resistances resulting from the surface accumulation of hydrogen bubbles. A model of this process is described and the resulting predictions are compared to the experimentally derived data. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Novel tobramycin inhalation powder in cystic fibrosis subjects: Pharmacokinetics and safetyPEDIATRIC PULMONOLOGY, Issue 4 2007David E. Geller MD Abstract Aerosolized antibiotics are associated with a high treatment burden that can result in non-adherence to chronic therapy. We evaluated the pharmacokinetics (PK) and safety of tobramycin inhalation powder (TIP), a novel dry-powder formulation designed to deliver a high payload of tobramycin topically to the lungs for management of chronic Pseudomonas aeruginosa infections. This was a multi-center, open-label, sequential-cohort, single-dose, dose-escalation study using the standard 300 mg dose of tobramycin solution for inhalation (TSI) as an active control. Subjects were randomized to TIP or TSI in a 3:1 ratio in each of five cohorts. Measurements included serum and sputum tobramycin concentrations, administration time, serum chemistries, acute change in lung function, and adverse events (AEs). Out of 90 randomized subjects, 86 had data for safety analysis; and 84 had data for PK analysis. Serum tobramycin PK profiles were similar for TIP and TSI. Four capsules of 28 mg TIP (total tobramycin dose 112 mg) produced comparable systemic exposure to 300 mg TSI, in less than one-third the administration time. The most common AEs associated with TIP were cough (20%) and dysgeusia (17%). TIP allows for faster and more efficient pulmonary delivery of tobramycin than TSI and has a safety profile that supports continued clinical investigation. The increased rate of local respiratory tract irritation noted with TIP is not unexpected with a high-payload powder formulation. The development of dry powder inhaled antibiotics may represent an important advance in the treatment of chronic lung infections. Pediatr Pulmonol. 2007; 42:307,313. © 2007 Wiley-Liss, Inc. [source] Detection of Left Ventricle Function From a Magnetically Levitated Impeller BehaviorARTIFICIAL ORGANS, Issue 5 2006Hideo Hoshi Abstract:, The magnetically levitated (Mag-Lev) centrifugal rotary blood pump (CRBP) with two-degrees-of-freedom active control is promising for safe and long-term support of circulation. In this study, Mag-Lev CRBP controllability and impeller behavior were studied in the simulated heart failure circulatory model. A pneumatically driven pulsatile blood pump (Medos VAD [ventricular assist device]-54 mL) was used to simulate the left ventricle (LV). The Mag-Lev CRBP was placed between the LV apex and aortic compliance tank simulating LV assistance. The impeller behavior in five axes (x, y, z, ,, and ,) was continuously monitored using five eddy current sensors. The signals of the x - and y -axes were used for feedback active control, while the behaviors of the other three axes were passively controlled by the permanent magnets. In the static mock circuit, the impeller movement was controlled to within ±10,±20 µm in the x- and y -axes, while in the pulsatile circuit, LV pulsation was modulated in the impeller movement with the amplitude being 2,22 µm. The amplitude of impeller movement measured at 1800 rpm with the simulated failing heart (peak LV pressure [LVP] = 70 mm Hg, mean aortic pressure [AoPmean] = 55 ± 20 mm Hg, aortic flow = 2.7 L/min) was 12.6 µm, while it increased to 19.2 µm with the recovered heart (peak LVP = 122 mm Hg, AoPmean = 100 ± 20 mm Hg, aortic flow = 3.9 L/min). The impeller repeated the reciprocating movement from the center of the pump toward the outlet port with LV pulsation. Angular rotation (,, ,) was around ±0.002 rad without z -axis displacement. Power requirements ranged from 0.6 to 0.9 W. Five-axis impeller behavior and Mag-Lev controller stability were demonstrated in the pulsatile mock circuit. Noncontact drive and low power requirements were shown despite the effects of LV pulsation. The impeller position signals in the x - and y -axes reflected LV function. The Mag-Lev CRBP is effective not only for noncontact low power control of the impeller, but also for diagnosis of cardiac function noninvasively. [source] Challenges and regulatory experiences with non-inferiority trial design without placebo armBIOMETRICAL JOURNAL, Issue 2 2009H. M. James Hung Abstract For a non-inferiority trial without a placebo arm, the direct comparison between the test treatment and the selected positive control is in principle the only basis for statistical inference. Therefore, evaluating the test treatment relative to the non-existent placebo presents extreme challenges and requires some kind of bridging from the past to the present with no current placebo data. For such inference based partly on an indirect bridging manipulation, fixed margin method and synthesis method are the two widely discussed methods in the recent literature. There are major differences in statistical inference paradigm between the two methods. The fixed margin method employs the historical data that assess the performances of the active control versus a placebo to guide the selection of the non-inferiority margin. Such guidance is not part of the ultimate statistical inference in the non-inferiority trial. In contrast, the synthesis method connects the historical data to the non-inferiority trial data for making broader inferences relating the test treatment to the non-existent current placebo. On the other hand, the type I error rate associated with the direct comparison between the test treatment and the active control cannot shed any light on the appropriateness of the indirect inference for faring the test treatment against the non-existent placebo. This work explores an approach for assessing the impact of potential bias due to violation of a key statistical assumption to guide determination of the non-inferiority margin. [source] Re-Formulating Non-inferiority Trials as Superiority Trials: The Case of Binary OutcomesBIOMETRICAL JOURNAL, Issue 1 2009Valerie L. Durkalski Abstract Non-inferiority trials are conducted for a variety of reasons including to show that a new treatment has a negligible reduction in efficacy or safety when compared to the current standard treatment, or a more complex setting of showing that a new treatment has a negligible reduction in efficacy when compared to the current standard yet is superior in terms of other treatment characteristics. The latter reason for conducting a non-inferiority trial presents the challenge of deciding on a balance between a suitable reduction in efficacy, known as the non-inferiority margin, in return for a gain in other important treatment characteristics/findings. It would be ideal to alleviate the dilemma on the choice of margin in this setting by reverting to a traditional superiority trial design where a single p -value for superiority of both the most important endpoint (efficacy) and the most important finding (treatment characteristic) is provided. We discuss how this can be done using the information-preserving composite endpoint (IPCE) approach and consider binary outcome cases in which the combination of efficacy and treatment characteristics, but not one itself, paints a clear picture that the novel treatment is superior to the active control (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Some Remarks About the Analysis of Active Control StudiesBIOMETRICAL JOURNAL, Issue 5 2005John Lawrence Abstract In an active-controlled trial, the experimental treatment can be declared to be non-inferior to the control if the confidence interval for the difference excludes a fixed pre-specified margin. Recently, some articles have discussed an alternative method where the data from the current study and placebo-controlled studies for the active control are combined together into a single test statistic to test whether a fixed fraction of the effect of the active control is preserved. It has been shown that, conditional on nuisance parameters from the active-controlled study, a fixed margin can be defined that will be operationally equivalent to this latter method. In this article, we will discuss statistical properties associated with these approaches. Specifically, the interim monitoring boundaries and level of evidence will be considered. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Sequential Tests for Noninferiority and SuperiorityBIOMETRICS, Issue 1 2003W. Brannath Summary. The problem of simultaneous sequential tests for noninferiority and superiority of a treatment, as compared to an active control, is considered in terms of continuous hierarchical families of one-sided null hypotheses, in the framework of group sequential and adaptive two-stage designs. The crucial point is that the decision boundaries for the individual null hypotheses may vary over the parameter space. This allows one to construct designs where, e.g., a rigid stopping criterion is chosen, rejecting or accepting all individual null hypotheses simultaneously. Another possibility is to use monitoring type stopping boundaries, which leave some flexibility to the experimenter: he can decide, at the interim analysis, whether he is satisfied with the noninferiority margin achieved at this stage, or wants to go for more at the second stage. In the case where he proceeds to the second stage, he may perform midtrial design modifications (e.g., reassess the sample size). The proposed approach allows one to "spend," e.g., less of , for an early proof of noninferiority than for an early proof of superiority, and is illustrated by typical examples. [source] Microfluidic biolector,microfluidic bioprocess control in microtiter platesBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010Matthias Funke Abstract In industrial-scale biotechnological processes, the active control of the pH-value combined with the controlled feeding of substrate solutions (fed-batch) is the standard strategy to cultivate both prokaryotic and eukaryotic cells. On the contrary, for small-scale cultivations, much simpler batch experiments with no process control are performed. This lack of process control often hinders researchers to scale-up and scale-down fermentation experiments, because the microbial metabolism and thereby the growth and production kinetics drastically changes depending on the cultivation strategy applied. While small-scale batches are typically performed highly parallel and in high throughput, large-scale cultivations demand sophisticated equipment for process control which is in most cases costly and difficult to handle. Currently, there is no technical system on the market that realizes simple process control in high throughput. The novel concept of a microfermentation system described in this work combines a fiber-optic online-monitoring device for microtiter plates (MTPs),the BioLector technology,together with microfluidic control of cultivation processes in volumes below 1,mL. In the microfluidic chip, a micropump is integrated to realize distinct substrate flow rates during fed-batch cultivation in microscale. Hence, a cultivation system with several distinct advantages could be established: (1) high information output on a microscale; (2) many experiments can be performed in parallel and be automated using MTPs; (3) this system is user-friendly and can easily be transferred to a disposable single-use system. This article elucidates this new concept and illustrates applications in fermentations of Escherichia coli under pH-controlled and fed-batch conditions in shaken MTPs. Biotechnol. Bioeng. 2010;107: 497,505. © 2010 Wiley Periodicals, Inc. [source] Spatial Reasoning With External Visualizations: What Matters Is What You See, Not Whether You InteractCOGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 7 2008Madeleine Keehner Abstract Three experiments examined the effects of interactive visualizations and spatial abilities on a task requiring participants to infer and draw cross sections of a three-dimensional (3D) object. The experiments manipulated whether participants could interactively control a virtual 3D visualization of the object while performing the task, and compared participants who were allowed interactive control of the visualization to those who were not allowed control. In Experiment 1, interactivity produced better performance than passive viewing, but the advantage of interactivity disappeared in Experiment 2 when visual input for the two conditions in a yoked design was equalized. In Experiments 2 and 3, differences in how interactive participants manipulated the visualization were large and related to performance. In Experiment 3, non-interactive participants who watched optimal movements of the display performed as well as interactive participants who manipulated the visualization effectively and better than interactive participants who manipulated the visualization ineffectively. Spatial ability made an independent contribution to performance on the spatial reasoning task, but did not predict patterns of interactive behavior. These experiments indicate that providing participants with active control of a computer visualization does not necessarily enhance task performance, whereas seeing the most task-relevant information does, and this is true regardless of whether the task-relevant information is obtained actively or passively. [source] The prevalence of mental health problems in Ethiopian child laborersTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 9 2006Daniel Fekadu Background:, Child labor refers to a state when a child is involved in exploitative economical activities that are mentally, physically, and socially hazardous. There are no prevalence studies on the magnitude of psychiatric disorders among child laborers. Methods:, A cross-sectional population survey was conducted in Addis Ababa using the Diagnostic Interview for Children and Adolescents (DICA). Subjects were a random sample of 528 child laborers aged between 5 and 15 years and comprising child domestics, street-workers and private enterprise workers. These were compared with 472 non-economically active controls. Results:, The aggregate prevalence of any DSM-III-R childhood emotional and behavioral disorders was found to be 16.5%, with 20.1% and 12.5% among child laborers and controls respectively, OR = 1.89 (95% CI, 1.34,2.67, p < .01). Internalizing disorders such as mood disorders were significantly higher among the laborers than the non-laborers, OR = 6.65 (95% CI, 2.20,22.52, p = .0001). Anxiety disorder was seen over twofold among child laborers while psychosocial stressors were one and half times more likely among the study subjects than controls. When all factors were taken into account, child labor status was the only significant factor in determining DSM-III-R diagnosis. Conclusion:, In this study childhood emotional and behavioral disorders are found to be more common among child laborers than among non-laborers. We recommend a larger study to look into childhood disorders and risk factors in child labor. As part of the concerted effort, government, NGOs, and the public should at least view child labor as a menace in a child's development, with risk of psychosocial difficulties. [source] Doxazosin for treating lower urinary tract symptoms compatible with benign prostatic obstruction: a systematic review of efficacy and adverse effectsBJU INTERNATIONAL, Issue 9 2004Roderick MacDonald The first paper in this section is a systematic review of the efficacy and adverse effects of doxazosin for treating LUTS compatible with benign prostatic obstruction. The criteria for inclusion were met by 13 studies involving 6033 men. The authors found evidence that doxazosin was effective and well tolerated in patients with LUTS. Combined therapy was superior to doxazosin alone in reducing the risk of clinical progression and other long-term complications of this condition. Authors from the UK reviewed the long-term results they achieved with an endourethral stent for treating BPH; quite a large proportion of patients had either died from unrelated causes or had had the stent removed. They stressed the necessity for careful case selection, but showed that it was a safe treatment for BPH in poor-risk patients. OBJECTIVE To evaluate the efficacy and adverse effects of doxazosin for treating lower urinary tract symptoms (LUTS) compatible with benign prostatic obstruction (BPO). METHODS Randomized controlled trials were included in the meta-analysis if: the study duration was ,,1 month; the study involved men with symptomatic BPO; and doxazosin was compared with placebo or active controls. Study and patient characteristics and outcome data were extracted in duplicate onto standardized forms using a prospectively developed protocol. RESULTS Thirteen studies involving 6033 men with (mean age 64 years) met the inclusion criteria; 10 were placebo-controlled, including two with combined doxazosin/finasteride therapy and finasteride monotherapy arms. Three trials were a comparison with other ,-blockers. The study duration was 1,54 months. The mean baseline symptom scores and peak urinary flow (PUF) rates were indicative of moderate BPO. Doxazosin gave significant improvements in LUTS, assessed by symptom scores, vs placebo and finasteride in the short- to long-term. Two long-term studies (1 and 4 years) reported mean changes from baseline for the International Prostate Symptom Score of ,,8.3 and ,,6.6 points (,49% and ,,39%) for doxazosin and ,,5.7 and ,,4.9 points (,33% and ,,29%) for placebo, respectively. Doxazosin significantly increased PUF rates vs placebo. In pooled results from three studies, the weighted mean difference in the mean change from baseline vs placebo was 1.6 mL/s (95% confidence interval 1.2,2.1). Efficacy was comparable with other ,1,blockers. In the long-term (>4 years) doxazosin was no better then finasteride in improving PUF. Combined doxazosin and finasteride significantly reduced the risk of overall clinical progression of BPO vs each drug separately in men followed for >4 years. Absolute risk reductions vs placebo were 11.3%, 6.9% and 6.4% for combined therapy, doxazosin and finasteride, respectively (P < 0.001). Improvements in symptom scores and PUF were also significantly greater with combined than monotherapy, and the former reduced the need for invasive treatment for BPO and the risk of long-term urinary retention, although the absolute reductions in risk vs placebo were small (<4%). Dizziness and fatigue were significantly more common with doxazosin than placebo (11% vs 7%, and 6% vs 3%, respectively). Adverse events reported for combined therapy were similar to those with each monotherapy. CONCLUSION The evidence indicates that doxazosin is effective and generally well tolerated for improving LUTS and PUF in men with symptomatic BPO. Combined therapy was better than doxazosin alone in reducing the risk of clinical progression of BPO and other long-term complications related to BPO. [source] Terazosin for treating symptomatic benign prostatic obstruction: a systematic review of efficacy and adverse effectsBJU INTERNATIONAL, Issue 3 2002T.J. Wilt Objective To systematically review and evaluate the effectiveness and adverse effects of the ,-antagonist, terazosin, for treating urinary symptoms associated with benign prostatic obstruction (BPO). Methods Studies were sought and included in the review if they were randomized trials of at least 1 month duration, involved men with symptomatic BPO and compared terazosin with placebo or active controls. The study, patient characteristics and outcome data were extracted in duplicate onto standardized forms using a prospectively developed protocol. Results Seventeen studies involving 5151 men met the inclusion criteria, i.e. placebo-controlled (10), ,-blockers (seven), finasteride alone or combined with terazosin and placebo (one), and microwave therapy (one). The study duration was 4,52 weeks; the mean age of the men was 65 years and 82% were white. Baseline urological symptom scale scores and flow rates showed that men had moderate BPO. Efficacy outcomes were rarely reported in a way that allowed for data pooling, but indicated that terazosin improved symptom scores and flow rates more than did placebo or finasteride, and similarly to other ,-antagonists. The pooled mean percentage improvement for the Boyarsky symptom score was 37% for terazosin and 15% for placebo (four studies). The mean percentage improvement for the American Urological Association symptom score was 38%, compared with 17% and 20% for placebo and finasteride, respectively (two studies). The pooled mean improvement in the International Prostate Symptom Score of 40% was similar to that with tamsulosin (43%). Peak urinary flow rates improved more with terazosin (22%) than with placebo (11%) and finasteride (15%), but did not differ significantly from the other ,-antagonists. The percentage of men discontinuing terazosin was comparable with those receiving placebo and finasteride, but greater than with other ,-antagonists. Adverse effects were greater than with placebo and included dizziness, asthenia, headache and postural hypotension. Conclusions The available evidence indicates that terazosin improves the symptoms and flow rates associated with BPO; it was more effective than placebo or finasteride and similar to other ,-antagonists. Adverse effects were generally mild but more frequent than with other ,-antagonists and associated with a two- to four-fold increase in treatment discontinuation. [source] | ||||||||||||||||||||||