Another Agent (another + agent)

Distribution by Scientific Domains

Selected Abstracts


Jonathan Dinerstein
The ability for a given agent to adapt on-line to better interact with another agent is a difficult and important problem. This problem becomes even more difficult when the agent to interact with is a human, because humans learn quickly and behave nondeterministically. In this paper, we present a novel method whereby an agent can incrementally learn to predict the actions of another agent (even a human), and thereby can learn to better interact with that agent. We take a case-based approach, where the behavior of the other agent is learned in the form of state,action pairs. We generalize these cases either through continuous k -nearest neighbor, or a modified bounded minimax search. Through our case studies, our technique is empirically shown to require little storage, learn very quickly, and be fast and robust in practice. It can accurately predict actions several steps into the future. Our case studies include interactive virtual environments involving mixtures of synthetic agents and humans, with cooperative and/or competitive relationships. [source]

Synergistic Combinations of Anticonvulsant Agents: What Is the Evidence from Animal Experiments?

EPILEPSIA, Issue 3 2007
Danil M. Jonker
Summary:,Purpose: Combination therapy is often used in the treatment of seizures refractory to monotherapy. At the same time, the pharmacodynamic mechanisms that determine the combined efficacy of antiepileptic drugs (AEDs) are unknown, and this prevents a rational use of these drug combinations. We critically evaluate the existing evidence for pharmacodynamic synergism between AEDs from preclinical studies in animal models of epilepsy to identify useful combinations of mechanisms and to determine whether study outcome depends on the various research methods that are in use. Methods: Published articles were included if the studies were placebo-controlled, in vivo, or ex vivo animal studies investigating marketed or experimental AEDs. The animal models that were used in these studies, the primary molecular targets of the tested drugs, and the methods of interpretation were recorded. The potential association of these factors with the study outcome (synergism: yes or no) was assessed through logistic regression analysis. Results: In total, 107 studies were identified, in which 536 interaction experiments were conducted. In 54% of these experiments, the possibility of a pharmacokinetic interaction was not investigated. The majority of studies were conducted in the maximal electroshock model, and other established models were the pentylenetetrazole model, amygdala kindling, and the DBA/2 model. By far the most widely used method for interpretation of the results was evaluation of the effect of a threshold dose of one agent on the median effective dose (ED50) of another agent. Experiments relying on this method found synergism significantly more often compared with experiments relying on other methods (p < 0.001). Furthermore, experiments including antagonists of the AMPA receptor were more likely to find synergism in comparison with all other experiments (p < 0.001). Conclusions: Intensive preclinical research into the effects of AED combinations has not led to an understanding of the pharmacodynamic properties of AED combinations. Specifically, the majority of the preclinical studies are not adequately designed to distinguish between additive, synergistic, and antagonistic interactions. Quantitative pharmacokinetic,pharmacodynamic studies of selectively acting AEDs in a battery of animal models are necessary for the development of truly synergistic drug combinations. [source]

Eletriptan in Migraine Patients Reporting Unsatisfactory Response to Rizatriptan

HEADACHE, Issue 7 2006
Jerome Goldstein MD
Objective.,The objective of this open-label study was to evaluate the efficacy of switching patients who had a previous unsatisfactory response to rizatriptan to eletriptan 40 mg. Background.,The characteristics of individual migraine patients can vary tremendously and can have a significant impact on treatment outcomes. In addition, clinical experience has demonstrated that the triptans are not identical or interchangeable and that patients who respond poorly or who are dissatisfied with one agent can derive benefit by being switched to another agent within the triptan class. Methods.,Patients were eligible if they met International Headache Society criteria for migraine, with a frequency of 1 to 6 migraine attacks per month, and had documented "unsatisfactory treatment response" to rizatriptan within the past year (54% on the melt formulation; 46% on tablets). Reasons for dissatisfaction with rizatriptan (>1 could be cited) included inadequate (84%) or slow onset (50%) of pain relief, high recurrence rate (69%), and lack of improvement in associated symptoms (60%). One hundred twenty-three patients were eligible for treatment. Patients were instructed to take eletriptan 40 mg as soon as they were certain that their headache was a migraine, regardless of level of pain severity (8% treated headaches that were mild). Results.,Headache response at 2 hours (first-attack data) was 64%. Absence of nausea (from baseline to 2 hours) increased from 50% to 78%, absence of photophobia from 30% to 72%, and absence of phonophobia from 39% to 77%. Functional response at 2 hours was 63%, with 41% of patients reporting normal functioning. Treatment with eletriptan 40 mg was associated with a 27% to 40% reduction in migraine attack-related functional impairment, as measured by the PQ-7. Recurrence rates were 36.6%. Overall, 72% of patients rated eletriptan as a "good-to-excellent" treatment, and 78% reported overall satisfaction with the degree of headache relief. Conclusion.,The results of this study suggest that eletriptan is an efficacious treatment option for patients who are dissatisfied with their response to rizatriptan. [source]

Medical management of left-sided ulcerative colitis and ulcerative proctitis: Critical evaluation of therapeutic trials

Miguel Regueiro MD
Abstract Background: The goal of this work was to critically evaluate the published studies on the treatment of ulcerative proctitis (UP) and left-sided ulcerative colitis (L-UC). The results of this review provided the content for the accompanying treatment guidelines, Clinical Guidelines for the Medical Management of Left-sided Ulcerative Colitis and Ulcerative Proctitis: Summary Statement. Methods: All English language articles published between 1995 and September 2005 were identified through a comprehensive literature search using OVID and PubMed. The quality of the data supporting or rejecting the use of specific therapies was categorized by a data quality grading scale. An "A+" grade was assigned to treatment supported by multiple high-quality randomized controlled trials with consistent results, whereas a "D" grade was given to therapy supported only by expert opinion. The therapeutic efficacy of a treatment was defined by its success in treating UP and L-UC compared with placebo. A medication was ranked as "excellent" if it was specifically studied for UP and L-UC and had consistently positive results compared with placebo or another agent. Quality and efficacy scores were agreed on by author consensus. Results: For the acute treatment of UP or L-UC, the rectally administered corticosteroids and mesalazine (5-ASA), either alone or in combination with oral 5-ASAs, are the most effective therapy: evidence quality, A+; efficacy, excellent. Only rectally administered 5-ASA received an A+/excellent rating for maintenance of remission. Infliximab received an A+ grade for induction and maintenance of remission but only a "good" rating because the studies were performed in all UC, not specifically UP or L-UC. Conclusions: This critical evaluation of treatment provides a "report card" on medications available for the management of patients with UP and L-UC. The guidelines should provide a useful reference and supplement for physicians treating UC patients. [source]

Efficacy and safety of thalidomide in children and young adults with intractable inflammatory bowel disease: long-term results

Summary Background Anti-tumour necrosis factor- , antibodies are useful for the treatment of refractory Crohn's disease and ulcerative colitis. Thalidomide is another agent with tumour necrosis factor- , suppressive properties. Aim To investigate the long-term efficacy and safety of thalidomide in a group of children and young adults with refractory inflammatory bowel disease. Methods Twenty-eight patients with refractory moderate-severe inflammatory bowel disease (19 Crohn's disease, 9 ulcerative colitis) received thalidomide 1.5,2.5 mg/kg/day. Patients were assessed at baseline, at weeks 2, 4, 8 and 12, and then every 12 weeks by patient's diary, physical examinations, laboratory analyses and scoring on activity indexes. Primary outcomes were: (i) efficacy in inducing remission; and (ii) efficacy in maintaining remission. Results Remission was achieved with thalidomide in 21 of 28 (75%) patients (17 with Crohn's disease, 4 with ulcerative colitis). Mean duration of remission was 34.5 months. Sixteen of 20 (80%) patients suspended steroids. Reversible neuropathy occurred in seven of 28 (25%) patients, but only with cumulative doses over 28 g. Other side effects requiring thalidomide suspension were vertigo/somnolence (one of 28), and agitation/hallucinations (one of 28). Conclusions Thalidomide seems to be effective in inducing long-term remission in children and adolescents with intractable inflammatory bowel disease. Neuropathy is the main adverse effect, but appears to be cumulative dose-dependent, thus allowing long-term remission before drug suspension. [source]

Midazolam as a sole sedative for computed tomography imaging in pediatric patients

Summary Objective:, To evaluate the efficacy and adverse effects of i.v. midazolam as a sole agent for sedation in children for computed tomography (CT) imaging. Materials and Methods:, Prospective clinical trial in which 516 children under ASA classification II,IV (273 boys and 243 girls) in the age group of 6 months to 6 years for elective CT scan were enrolled over a 17-month period. Patients were administered i.v. midazolam 0.2 mgkg,1 and further boluses of 0.1 mgkg,1 (total 0.5 mgkg,1) if required. Measurements included induction time, efficacy, side effects, complications, and degree of sedation. Sedation was graded on the basis of Ramsay sedation score (RSS) as over sedated (RSS 5,6), adequately sedated (AS, RSS 3,4), under sedated (RSS 1,2), or failed if the procedure could not be completed or another agent had to be administered. Results:, Of the 516 procedures, 483 brains, 16 chests, and 17 abdomens were scanned with a mean duration of 4.75 1.75 min with a mean dose of 0.212 mgkg,1 of i.v. midazolam. Four hundred and sixty-five (90.12%) patients were AS in 5.9 0.7 min while 40 (7.75%) patients required additional boluses. Of these 40 patients, 24 (4.65%) required a single bolus, 12 (2.32%) required two boluses, whereas the remaining four (0.78%) required three boluses. In 11 (2.13%; P < 0.0001) patients, the scan could not be completed satisfactorily. Side effects were seen in 46 (9.11%) patients in the form of desaturation, hiccups (seven patients, 1.38%), and agitation (four patients, 0.79%). Desaturation (SpO2 90,95%) was seen in 35 (6.93%) patients, which was corrected by topical application of oxygen. None of the patients exhibited any complications such as pulmonary aspiration or need to maintain airway. The patients were kept under observation for 1 h after the procedure. Conclusion:, The level of sedation achieved in children with midazolam 0.2 mgkg,1 is adequate for imaging with minimal side effects, no airway complications, and fast recovery. It can be recommended as the sole agent for sedation in pediatric patients for CT imaging. [source]

Moral Cognitivism and Character

Craig Taylor
It may seem to follow from Peter Winch's claim in ,The Universalizability of Moral Judgements' that a certain class of first-person moral judgments are not universalizable that such judgments cannot be given a cognitivist interpretation. But Winch's argument does not involve the denial of moral cognitivism and in this paper I show how such judgements may be cognitively determined yet not universalizable. Drawing on an example from James Joyce's The Dead, I suggest that in the kind of situation Winch envisages where we properly return a different moral judgement to another agent it may be that we accept their judgement is right for them because we recognise that it is determined by values that, simply because of the particular people we are, we could never know or understand in just the same way. [source]

Contradiction as a form of Contractual Incompleteness,

Dana Heller
A simple model is presented, in which contradictory instructions are viewed as a type of contract incompleteness. The model provides a complexity-based rationale for contradictory instructions. If there are complexity bounds on the contract, there may be an incentive to introduce contradictions, leaving for another agent the task of interpreting them. The optimal amount of contradictions depends on the complexity bound, the conflict of interests with the interpreter and the institutional constraints on his interpretations. In particular, a higher complexity bound may result in a larger amount of contradictions. [source]