bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of D1 and α1 receptors in the enhanced locomotor response to dopamine D2-like receptor stimulation induced by repeated electroconvulsive shock
Authors: D'Aquila Paolo S. , Collu Maria , Gessa Gian Luigi , Serra Gino
Published: March 2007

We previously reported that, in rats chronically treated with the antidepressant drug imipramine, the enhanced locomotor response to the D2-like receptor agonist quinpirole became less sensitive to the inhibitory effect of the D1 receptor antagonist SCH 23390 and more sensitive to the inhibitory effect of the α1 receptor antagonist prazosin. In this study, we show that in electroconvulsive shock-treated rats these antagonists behave in the opposite manner to that observed in imipramine-treated rats, with SCH 23390 being highly effective and prazosin ineffective in antagonizing the locomotor response to quinpirole. The possibility that these differences may reflect some of the clinical characteristics of these antidepressant treatments is discussed.
Behavioural effects of selective serotonin reuptake inhibitors following direct micro injection into the left red nucleus of the rat
Authors: Faherty Ciaran J. , Earley Bernadette , Leonard Brian E.
Published: March 2007

The behavioural effects of selective serotonin reuptake inhibitors (paroxetine, sertraline, citalopram, fluvoxamine, fluoxetine) and reference compounds (N,N'-di( o-tolyl)guanidine, haloperidol, 3-(3-hydroxyphenyl)- N-(1-propyl)piperidine and chlorpromazine) were studied for their ability to produce dystonia and torticollis following direct micro injection into the left red nucleus of the rat, an area of the brain containing a high density of σ2 receptors but relatively devoid of biogenic amine receptors. Each animal was monitored for abnormalities in posture and movement for a period of 30 min and then sacrificed 40 min following drug administation. Only fluvoxamine (100 nmol) and fluoxetine (100 nmol) elicited acute dystonic behaviour (1- 5 min). The onset of dystonia was accompanied by facial spasticity, vacuous chewing movements and grooming behaviour which reflected the extent of dystonia. The dystonic behaviour following the direct intrarubal injection of fluvoxamine and fluoxetine suggest the possible activation of σ2 receptors while citalopram, sertraline and paroxetine were without effect. The results of this study support the role of σ2 receptors in the regulation and control of movement and co-ordination and provides preliminary evidence to suggest the in vivo activity of σ receptors by fluoxetine and fluvoxamine.
The nature of interactions involving prefrontal and striatal dopamine systems
Authors: Wilkinson L.S.
Published: March 2007

A number of converging lines of evidence from work in rodents suggest that dopamine (DA) function in the prefrontal cortex (PFC) and striatal terminal fields may be linked, possibly in an 'inverse' manner, whereby a change in prefrontal dopamine transmission in one direction occasions an opposite change in dopamine function in striatal territories. The present article considers the possible functional importance of this concept in the light of recent neuroanatomical data and new data from our own laboratory indicating that, at the neurochemical level, the basic finding of an inverse relationship between dopamine function in prefrontal and striatal regions also holds good in the non-human primate. The main conclusion is that the simple idea of an inverse relationship between prefrontal and striatal dopamine systems emphasizing presynaptic release mechanisms is unlikely to underlie, solely, the full repertoire of functional interactions. Whilst there is evidence consistent with dynamic interactions between prefrontal and striatal dopamine release under some circumstances, specifically, during the early phases of aversive learning, a complete account of possible interactions between prefrontal and striatal dopamine systems requires consideration of additional factors. Such factors include: (1) the precise nature of the psychological function investigated, (2) the possibility of acute, localized changes in striatal postsynaptic function secondary to changes in presynaptic function and (3) the possibility of manipulations of prefrontal cortex leading to adaptive changes in striatal function, at a diffuse, neural systems level.
Noradrenergic mechanisms in the prefrontal cortex
Authors: Nutt D.J. , Lalies M.D. , Lione L.A. , Hudson A.L.
Published: March 2007

There is growing evidence that noradrenergic inputs to the prefrontal cortex (PFC) play an important role in regulating its function. This paper reviews the pharmacological control of noradrenaline (NA) release in this region, with particular reference to our studies using brain microdialysis, and also describes how NA levels are modulated by antidepressant and antipsychotic drugs. The suggestion that atypical antipsychotics such as clozapine and risperidone may produce clinical benefits by their ability to increase NA release is discussed. Finally, a new class of drugs, which show selectivity for imidazoline receptors is described. These compounds are shown to similarly increase extracellular NA in the PFC. Their potential utility as clinical treatments is discussed.
Differences and variability in plasma noradrenaline between depressive and anxiety disorders
Authors: Kelly C.B. , Cooper S.J.
Published: March 2007

Plasma noradrenaline (NA) levels were compared between two groups of patients with major depressive disorder (melancholic/psychotic and non-melancholic), patients with general anxiety disorders and healthy controls. The melancholic/psychotic depressed group had the highest plasma NA levels. This only reached statistical significance with respect to the control group. Within the depressed group, there was no association between plasma NA levels and age, weight loss, ratings of depression, anxiety or plasma cortisol levels. Variance of plasma NA was greatest in the melancholic/psychotic depressed group. A review of previous studies shows an association between raised plasma NA, depressive illness and alterations in NA variance. This association may be limited to melancholic/psychotic depressed patients. The above findings support a dysregulated noradrenergic system in depressive illness.
The nitric oxide synthesis inhibitor L-NAME produces anxiogenic-like effects in the rat elevated plus-maze test, but not in the social interaction test
Authors: Vale A.L. , Green S. , Montgomery A.M.J. , Shafi S.
Published: March 2007

The effects of the nitric oxide synthase inhibitor, Nw-nitro-L-arginine methyl ester (L-NAME) were investigated in two animal models of anxiety: the elevated plus-maze and the social interaction test. In the elevated plus- maze, L-NAME (12.5-50 mg/kg) had an anxiogenic-like profile as indicated by dose-dependent reductions in the time spent on the open arms, open arm entries, the percentage of open arm entries and head dips, but there was no significant effect on the number of stretch attend postures. In contrast, L-NAME (12.5-50 mg/kg) failed to modify time spent in social interaction but did reduce a measure of vertical activity The differential effects of L-NAME in the two anxiety paradigms are discussed.
STS Perspective: Theology Not Ecology
Authors: Bahro Rudolf
Published: March 2007

Rudolf Bahro Once a loyal supporter of the East German Communist Party, Rudolf Bahro was arrested in 1977 after the publication of his book, The Alternative in Eastern Europe, in which he called for a Gorbachev-style perestroika a decade too early.

Released from prison in 1979 as a result of public- opinion pressure in the West, Bahro emigrated to West Germany where he became a founding theorist of the Green Party. His most recent book is entitled The Logic of Salvation.

NPQ Editor Nathan Gardels recently spoke with Bahro in the Eifel Mountain hamlet of Niederstadtfeldt where Bahro now makes his home.
A Chart Audit Study of the Referral of Obese Patients to Endocrinologists
Authors: Ravitch Michael M. , Rovner David R. , Jennett Penny A. , Rothert Marilyn L. , Holmes Margaret M. , Holzman Gerald B. , Elstein Arthur S.
Published: March 2007

The aim of this study was to identify factors in primary care physicians' decisions to refer obese patients to an endocrine clinic. Charts of 83 referred obese patients were compared with randomly selected charts of 300 obese adults in the general ambula tory clinic files. The referral rate is estimated at 1% of obese patients in the clinical center and 0.25% of obese persons in the Lansing area. Referral of obese patients appears to depend primarily on degree of obesity and secondarily on suspicion of endocrine disease. Considerations limiting the usefulness of patient charts for studies of physicians' decision making are discussed. (Med Decis Making 3:69-79, 1983)
Risk-Benefit Considerations in the Management of Polymyalgia Rheumatica
Authors: Chang Rowland W. , Fineberg Harvey V.
Published: March 2007

Management of the polymyalgia rheumatica syndrome (PMR) is controversial. Grat ifying symptomatic response usually occurs after treatment with nonsteroidal anti inflammatory drugs or low doses of corticosteroids. However, some PMR patients are at risk of sudden blindness from an associated disease, giant cell arteritis (GCA). Blindness can be prevented by using higher and more toxic doses of corticosteroids. Temporal artery biopsy can be an aid in diagnosis, though it is not a completely sen sitive test for GCA.

This study employs decision analysis and derived risk-benefit ratios (equivalent to utility ratios) to evaluate five possible PMR management strategies. The incremental risk-benefit analysis provides a means for weighing intangible trade-offs without a formal utility analysis. Given base case assumptions derived from the literature, empirical treatment with high-dose steroids cannot be justified for PMR patients who have no cranial arteritic symptoms, because the acceptable risk-benefit ratio associated with this strategy is more than 90 cases of severe medication side effects per case of monocular blindness averted. (Med Decis Making 3:459-475, 1983)
The Decision Concerning Coronary Angiography in Patients with Chest Pain
Authors: Doubilet Peter , McNeil Barbara J. , Weinstein Milton C.
Published: March 2007

We examined the decision whether to perform coronary angiography (followed by bypass surgery if appropriate findings are present) in middle-aged men who have chest pain and have undergone exercise tolerance testing (ETT). We developed a model of this decision that combines data from a variety of sources and selects the optimal strategy based on health out come and, if desired, monetary cost. The analysis supports the following conclusions: (1) for patients with nonspecific chest pain or atypical angina, the ETT provides useful infor mation concerning the decision, furthermore, the number of millimeters of ST-segment depression above which angiography should be performed depends on coronary risk factors and pain severity. (2) A normal ETT is insufficient evidence to exclude coronary angiogra phy for patients with typical angina, provided that one is willing to expend resources for health benefits at levels comparable to those for other accepted medical practices. (3) If monetary considerations are excluded, the preceding statement concerning ETT and angiography also holds for patients with atypical angina and for those with nonspecific pain and advanced risk factors. These last two conclusions suggest that ETT is not useful in guid ing management decisions concerning coronary angiography in patients at high enough risk of coronary artery disease on the basis of symptoms and risk profile. (Med Decis Making 5:293-309, 1986)
The Superiority of Sequential Over Simultaneous Testing
Authors: Doubilet Peter M. , Cain Kevin C.
Published: March 2007

Diagnostic tests are typically used to help the physician select among available management options. When two or more tests are available, using them sequentially is potentially more efficient than simultaneously performing multiple tests, in that the former approach may allow the physician to perform fewer tests. In particular, we demonstrate that if two common conditions are met, any simultaneous strategy involving at least as many tests as management options can be replaced by a sequential strategy with the same outcome and a smaller expected number of tests. It follows that, in many clinical situations in which the benefits of performing fewer tests outweigh the costs that may result from delaying diagnosis, simultaneous strategies cannot be optimal. This result can decrease the number of diagnostic strategies that the physician or decision analyst needs to consider. (Med Decis Making 5:447-451, 1985)
Physicians' Estimates of the Probability of Myocardial Infarction in Emergency Boom Patients with chest Pain
Authors: Tierney William M. , Fitzgerald John , McHenry Ross , Roth Bruce J. , Psaty Bruce , Stump David L. , Anderson F. Kim
Published: March 2007

To evaluate the ability of emergency room physicians to estimate the probability of myocardial infarction in patients with acute chest pain, the authors gathered historical, physical, and electrocardiographic information from 492 patients at the time of their presentation. The physicians admitted 30% of them to intensive care: 53 of the 61 patients with infarctions (sensitivity = 87%) and 96 of the 431 without infarctions (specificity = 78%). Overall, 36% of those admitted had infarctions. The physicians' numeric estimate of the probability of infarction was a good univariate discriminator of infarction, as demonstrated by Receiver Operator Characteristics analysis, and, as indicated by their actual operating point, they seemed to maximize the accuracy of patient classification rather than sensitivity or specificity. Logistic regression analysis identified the physicians' probability estimate as the strongest multivariate predictor of infarction, considering all other clinical information available. Key words: probability; prediction; myocardial infarction. (Med Decis Making 6:12-17, 1986)
Threshold Analysis of Decision Tables
Authors: Glasziou Paul , Hilden Jörgen
Published: March 2007

When a decision table is used to find a maximum expected utility testing strategy, it is based on a given prior probability distribution of diseases. In the two-disease situation, a threshold analysis over all prior probabilities can be done using threshold transformations of the points of indifference between treatments. This results in a set of prior probability intervals each with its own unique decision rule. The Boolean expression for the table indicates the ac ceptable testing strategies. A decision table analysis may then be extended to include invasive or costly investigations. The technique represents a saving in time and effort com pared with standard decision tree approaches, especially where investigative recommen dations are to be made for a broad range of prior probabilities, e.g., where initial symptoms and signs are considered before the investigations.
The Importance of considering single Testing When Two Tests Are Available
Authors: Hershey John C. , Cebul Randall D. , Williams Sankey V.
Published: March 2007

When considering two dichotomous tests in combination for reaching a treatment decision, the choice between single and multiple testing depends, in part, on the pretest probability of disease. The authors show that two tests are never preferred to a single test for all disease probabilities, regardless of whether the two tests are performed in parallel or in series. Key words: decision analytic model; tests with dichotomous outcomes; parallel testing; series testing. (Med Decis Making 7:212-219, 1987)
How Did the Acute Ischemic Heart Disease Predictiue Instrument Reduce Unnecessary Coronary Care Unit Admissions?
Authors: McNutt Robert A. , Selker Harry P.
Published: March 2007

The use of the acute ischemic heart disease predictive instrument reduced coronary care unit (CCU) admissions for patients without acute ischemic heart disease by 30%. One hypothesis holds that it reinforced physicians' correctly low estimates of the probability of acute ischemia, supporting a decision against CCU admission, another that it lowered phy sicians' over-high probability estimates for acute ischemia so that CCU admission was felt to be unnecessary. The authors asked 86 physicians to estimate the probability of acute ischemia for each of three study cases and to decide on CCU admission. For the low- probability case, the mean of physicians' probability estimates for acute ischemia was 46%, vs. the predictive instrument's calculated probability of 19% (p < 0.00001), a 142% over- estimation by the physicians. For the medium-probability case, the mean of physicians' estimates was 54%, vs. the calculated probability of 58% (not significant). For the high- probability case, the mean of physicians' estimates was 82%, vs. the calculated probability of 78% (not significant). All cases for which physicians considered not admitting to the CCU corresponded to their probability estimates of acute ischemia's being in a threshold range of approximately 10 to 30%. These results support the hypothesis that the mechanism by which the predictive instrument reduces unnecessary CCU admissions is by downward correction of physicians' overly-high suspicions of acute cardiac ischemia into a threshold range for which CCU admission is considered unnecessary. Key words: cardiac ischemia; coronary care; probability threshold. (Med Decis Making 8:90-94, 1988)
Strategies for Screening for Colorectal Carcinoma
Authors: England William L. , Halls Juanita J. , Hunt Vernon B.
Published: March 2007

Four tests commonly used in screening strategies to detect colorectal cancer were examined from a cost-effectiveness perspective. Thirteen combinations of the tests were evaluated. Evaluating a positive fecal occult blood test with a double-contrast barium enema study, followed, if necessary, by colonoscopy, is the most cost-effective strategy for individuals at average risk. An alternative screening strategy for higher-risk individuals or for populations in which the frequency of adenomatous polyps is higher is to follow a positive fecal occult blood test directly with colonoscopy. Sensitivity analysis demonstrated that the superior cost- effectiveness of these two strategies compared with the other 11 modeled strategies is almost independent for reasonable alterations in test cost and for the sensitivities and spec ificities of the procecures. The major contributing factor to the diagnostic cost is the frequency of adenomatous polyps. The major contributing factor to the marginal cost per year of extended life is the frequency of cancer.
Characterizing Physicians' Perceptions of Ambiguity
Authors: Curley Shawn P. , Young Mark J. , Yates J. Frank
Published: March 2007

Ambiguity, typically characterized as imprecision in judged probabilities, is distinguishable from that uncertainty typically measured using probabilities. It reflects the inadequacy of a point probability judgment and the assumptions upon which it is based. Ambiguity influences both patients' and physicians' decisions, but it is unknown how decision makers conceptualize ambiguity. Toward this goal, properties of three ambiguity indicators were examined: a confidence rating, a plausible range, and an interquartile range. Board-certified internists and fourth-year medical students evaluated simulated cases of suspected coronary artery disease. Their judgments provided insights into the three ambiguity indicators. The distri bution-based interquartile range was largely redundant with the plausible range, and was least adequate. The confidence rating was not equivalent to the plausible range, and ap peared to best reflect the construct of ambiguity as it has been defined. Key words: ambiguity; probability judgments; decision making. (Med Decis Making 1989;9:116-124)
The Reliability of Probability Analysis in the Prediction of Coronary Artery Disease in Two Hospitals
Authors: Guppy Kern H. , Detrano Robert , Abbassi Nabil , Janosi Andras , Sandhu Sarbjit , Froelicher Victor
Published: March 2007

To assess the accuracy of the Bayesian computer program CADENZA for the prediction of coronary artery disease, the authors examined the probabilities generated by the application of this program to the clinical and noninvasive test results of 303 patients in a private referral center and 199 patients in a veterans' hospital. These probabilities were compared with those produced by applying a six-variable discriminant function derived by logistic regression at the private referral center. Two statistical approaches were employed in evaluating the relative performances of the Bayesian program and the discriminant function. The first of these involved the sorting of patients in both test groups into ascending deciles of probability and comparing expected probability with observed angiographic disease prevalence in each decile. The second involved the calculation and comparison of a standardized reliability measure. The lafter was significantly lower for the discriminant function both at the private hospital (0.200 for the discriminant function versus -17.5 ± 1.96 for the Bayesian program) and at the veterans' hospital ( - 0.8 ± 1.96 for the discriminant function versus -11.3 for Bayesian program). This suggests that the discriminant function is significantly superior to the Bayesian algorithm CADENZA for predicting coronary artery disease probabilities in subjects who have relatively high pretest disease probabilities.
The High Cost and Low Efficacy of Weekly Viral Cultures for Pregnant Women with Recurrent Genital Herpes
Authors: Binkin Nancy J. , Koplan Jeffrey P.
Published: March 2007

The use of weekly cultures to prevent neonatal infection among infants of pregnant women who have histories of genital herpes has been controversial since a decision analysis study in 1983 suggested that this strategy was not cost-effective and would avert relatively few cases of neonatal herpes simplex virus infection. Using more recent and better data, the authors reanalyzed this approach to reducing neonatal herpes infection. The reanalysis revealed that a national screening program would prevent only 1.8 cases of neonatal herpes in the United States annually, at a cost of more than 37 million dollars per case averted. The program would cost nearly 7 million dollars per quality-adjusted life year gained when only infant deaths are taken into consideration. When maternal deaths from excess cesarean deliveries are taken into account, over 44 million dollars would be spent for every quality- adjusted life-year gained. On the basis of the strategy's limited benefits and low cost- effectiveness, the authors support the American College of Obstetrics and Gynecology's position of abandoning the recommendation for weekly prenatal herpes cultures. Key words: herpes; neonatal; screening; cost-effectiveness. (Med Decis Making 1989;9:225-230)
Domain Knowledge and Hypothesis Genenation in Diagnostic Reasoning
Authors: Joseph Guy-Marie , Patel Vimla L.
Published: March 2007

The role of domain knowledge in the process of hypothesis generation during diagnostic reasoning was examined. Subjects were given a clinical case presented one segment at a time on a microcomputer. They were prompted to think aloud after presentation of each segment of the clinical case. A combination of discourse and protocol analysis techniques was used to investigate the problem solving process in two groups of experts working on an endocrine problem. The groups consisted of high-domain-knowledge subjects (HDK), endocrinologists, and low-domain-knowledge subjects (LDK), cardiologists. The results showed no significant differences between the groups in terms of selection of relevant and critical cues from the case. However, specific differences were found in the links or relations between the cues, with the HDK subjects using more relations to connect important information. The HDK subjects generated accurate diagnostic hypotheses early in the problem encounter and spent the rest of the time confirming the hypotheses by explaining the given cues. The LDK subjects also generated accurate diagnostic hypotheses but were unable to discriminate between and eliminate alternative hypotheses. A two-stage problem solving process and its relationship to domain specific knowledge are proposed. Key words: medical problem solving; hypothesis generation; psychological processes; expert reasoning. (Med Decis Making 1990;10:31-46)
Targeting Assessments of Magnetic Resonance Imaging in suspected Multiple sclerosis
Authors: Mooney Cathleen , Mushlin Alvin I. , Phelps Charles E.
Published: March 2007

Decision-analytic methods can be valuable for targeting research in technology assessment. They can indicate whether further evaluation of a technology is warranted, and if so, which variables are key determinants of its clinical utility and cost-effectiveness. This approach was tested on a salient issue—whether magnetic resonance imaging (MR) should be used in evaluating patients with mild neurologic symptoms who might have multiple sclerosis (MS). The authors developed a decision-analytic model to assess the expected utility and costs associated with immediately using MR in this situation, compared with waiting for further symptoms to emerge before testing. Sensitivity analyses demonstrated that priorities for technology assessment research include estimating the value of information to patients in resolving uncertainty, evaluating the impact on patients of being labeled with a diagnosis of MS, and measuring the test characteristics of MR. Key words: cost-benefit analysis; multiple sclerosis; magnetic resonance imaging; decision analysis; Markov models. (Med Decis Making 1990;10:77-94)
Enhancing and Evaluating Diagnostic Accuracy
Authors: Swets John A. , Getty David J. , Pickett Ronald M. , D'Orsi Carl J. , Seltzer Steven E. , McNeil Barbara J.
Published: March 2007

Techniques that may enhance diagnostic accuracy in clinical settings were tested in the context of mammography. Statistical information about the relevant features among those visible in a mammogram and about their relative importances in the diagnosis of breast cancer was the basis of two decision aids for radiologists: a checklist that guides the ra diologist in assigning a scale value to each significant feature of the images of a particular case, and a computer program that merges those scale values optimally to estimate a probability of malignancy. A test set of approximately 150 proven cases (including normals and benign and malignant lesions) was interpreted by six radiologists, first in their usual manner and later with the decision aids. The enhancing effect of these feature-analytic techniques was analyzed across subsets of cases that were restricted progressively to more and more difficult cases, where difficulty was defined in terms of the radiologists' judgments in the standard reading condition. Accuracy in both standard and enhanced conditions de creased regularly and substantially as case difficulty increased, but differentially, such that the enhancement effect grew regularly and substantially. For the most difficult case sets, the observed increases in accuracy translated into an increase of about 0.15 in sensitivity (true-positive proportion) for a selected specificity (true-negative proportion) of 0.85 or a similar increase in specificity for a selected sensitivity of 0.85. That measured accuracy can depend on case-set difficulty to different degrees for two diagnostic approaches has general implications for evaluation in clinical medicine. Comparative, as well as absolute, assess ments of diagnostic performances—for example, of alternative imaging techniques—may be distorted by inadequate treatments of this experimental variable. Subset analysis, as defined and illustrated here, can be useful in alleviating the problem. Key words: computer- aided diagnosis; expert systems; technology assessment; quality assurance; diagnostic ac curacy; ROC analysis; feature analysis; cognitive processes; perception. (Med Decis Making 1991;11:9-18)
The Impact of a Rapid Screen for Streptococcal Pharyngitis on Clinical Decision Making in the Emergency Department
Authors: Hedges Jerris R. , Singal Bonita M. , Estep Jennifer L.
Published: March 2007

The impact of a rapid streptococcal screening test (RSS) on clinical decision making in the management of patients with acute pharyngitis was evaluated. Physicians managing 95 ambulatory patients with the complaint of sore throat were asked to estimate the probability of group A β-hemolytic streptococcal pharyngitis (GRABS) in each patient and whether they intended to treat with antibiotics both before and after the results of the RSS were known. Simultaneous throat cultures were obtained for 80 patients at the discretion of the treating physicians. Regression analysis revealed that the RSS result was an important independent predictor for the posttest decision to treat with antibiotics and for the estimated probability of disease. The mean absolute log-likelihood ratio was used to quantify the effect of the RSS on diagnostic certainty; a greater contribution to diagnostic certainty occurred when the RSS was positive. Physicians would have prescribed an antibiotic 49 times without the benefit of the RSS and prescribed an antibiotic 48 times given the RSS result. Without the RSS, the treatment decision contradicted the throat culture result in 25 cases. With the RSS, this occurred in 26 cases. The RSS, while influencing decision making, especially when positive, did not decrease the use of antibiotics.
Cost - Effectiveness of Prophylactic AZT Following Neediestick Injury in Health Care Workers
Authors: Ramsey Scott D. , Nettleman Mary D.
Published: March 2007

In response to health care workers' concerns about contracting infection with the human immunodeficiency virus (HIV) in the workplace, several institutions now offer prophylactic azido-deoxythymidine (AZT) for needlesticks sustained while exposed to HIV-infected pa tients. The authors designed a model to evaluate the cost-effectiveness of AZT prophylaxis. If AZT were 100% effective, prophylaxis would cost $2,388 per life-year gained and $66,876 per life saved using a societal perspective. For each $100 increase in the cost of AZT, the cost per life-year saved increased $1,190. Reducing the efficacy of AZT to 75, 50, and 25% raised the costs per life-year gained to $3,184, $4,775, and $9,551, respectively If AZT were given for all needlesticks without regard to the HIV status of the source, the costs of prophylaxis would rise substantially. It is concluded that AZT, if moderately effective, can be cost-effective as a prophylactic agent but only if used in instances where the source is known to have an HIV infection. Key words. human immunodeficiency virus, azido-deoxy thymidine ; cost-effectiveness; needlesticks. (Med Decis Making 1992;12:142-148)
Comparing Methods of Learning Clinical Prediction from Case Simulations
Authors: Tape Thomas G. , Kripal Jerry , Wigton Robert S.
Published: March 2007

Feedback to physicians about how they use information in making judgments can improve the quality of their judgments, but questions remain about which types of feedback are most effective. The authors conducted a controlled study of feedback in 60 medical students learning to predict the risk of cardiovascular death based on the presence or absence of five risk factors. After a pretest of 40 cases abstracted from patient records, the students worked through 173 computer-simulated cases and a posttest of 40 patient cases. The students received no feedback, probability feedback (correct probability of cardiac death for each case), cognitive feedback (the correct cue weights compared with their own weights derived from the previous set of cases), or both types of feedback. Students who received probability feedback markedly improved both base rate calibration and discrimination. Those who received only cognitive feedback showed no improvement over control on any of the measures of learning. All subjects were highly consistent in their weightings. The superiority of probability feedback differed from previous findings that cognitive feedback was essential for mastery of multiple-cue-probability learning tasks. The information on cue-outcome relationships given by cognitive feedback may be more useful when these relationships are complex and the combining rule is not known, while the precise outcome information provided by probabilistic feedback is more useful when the combining rule is known and the cue- outcome relationships are straightforward. Thus, the optimal method of learning depends on the nature of the task. Key words: risk factors; computer simulations; heart disease. (Med Decis Making 1992;12:213-221)
Treatment of Chronic Nonvalvular Atrial Fibrillation in the Elderly
Authors: Naglie I. Gary , Detsky Allan S.
Published: March 2007

The objective of the study was to determine the preferred treatment strategy for elderly patients with chronic nonvalvular atrial fibrillation (CNVAF). A Markov decision-analytic model was used to compare three treatment strategies for CNVAF: 1) warfarin; 2) aspirin; and 3) no treatment. Five-year quality-adjusted life years (QALYs) were calculated for male and female cohorts aged 70 and 75 years. In the baseline analysis (effectiveness of warfarin = 0.70, effectiveness of aspirin = 0.45, utility of warfarin = 0.99, and utility of aspirin = 0.999) the quality-adjusted survival rates for 70-year-old males were 4.03 QALYs on warfarin, 4.02 QALYs on aspirin, and 3.95 QALYs on no treatment. Results were similar for all age and sex cohorts. Sensitivity analyses revealed that the results were very sensitive to the effec tiveness of aspirin and the disutility of warfarin. The authors conclude that the optimal strategy for the treatment of CNVAF in elderly patients varies with the disutility assigned to warfarin therapy and the effectiveness value for aspirin therapy. Key words: chronic atrial fibrillation; elderly; anticoagulation; warfarin; aspirin; decision analysis; Markov analysis; quality of life. (Med Decis Making 1992;12:239-249)
Birthweight-adjusted Mortality Rates for Assessing the Effectiueness of Neonatal Intensive Care
Authors: Horbar Jeffrey D.
Published: March 2007

Mortality rates for very-low-birthweight infants vary significantly among different neonatal intensive care units (NICUs). Computational models and computer simulation are used to predict the performance of an algorithm for identifying individual NICUs within a network that have greater than 110% of the expected birthweight-adjusted mortality risk. The algorithm maintains high sensitivity and specificity with as few as three moderately heterogeneous risk categories when applied to large health care networks; the model parameters were based on preliminary data from a real NICU network. The performance of the algorithm depends on the number of admissions at the individual NICU. A NICU with a center-specific risk 130% of the network average would be correctly identified as an outlier 50% of the time if it had 35 admissions, 59% of the time if it had 70 admissions, and 77% of the time if it had 280 admissions. A NICU with average risk would be incorrectly identified as an outlier 16%, 12%, or 2% of the time if it had 35, 70, or 280 admissions, respectively. Severity-of-illness casemix adjustment did not improve these results. It is concluded that the sensitivity and specificity of the algorithm in determining which facilities have higher-than-expected mortality will be less in typical NICU networks than in large health care networks that treat adult patients. It is unlikely that severity-of-illness adjustments will overcome the problem of the small numbers of admissions at individual NICUs. Key words: neonate; mortality; birthweight; risk-adjust ment simulation; healthcare outcomes; casemix correction. (Med Decis Making 1992;12:259- 264)
Factored Stochastic Trees
Authors: Hazen Gordon B.
Published: March 2007

The stochastic tree is a continuous-time version of a Markov-cycle tree, useful for constructing and solving medical decision models in which risks of mortality and morbidity may extend over time. Stochastic trees have advantages over Markov-cycle trees in graphic display and computational solution. Like the decision tree or Markov-cycle tree, stochastic tree models of complex medical decision problems can be too large for convenient graphic formulation and display. This paper introduces the notion of factoring a large stochastic tree into simpler components, each of which may be easily displayed. It also shows how the rollback solution procedure for unfactored stochastic trees may be conveniently adapted to solve factored trees. These concepts are illustrated using published examples from the medical literature. Key words: stochastic trees; DEALE models; decision analysis; Markov-cycle trees; temporal medical decision modeling. (Med Decis Making 1993;13:227-236)
Cost - Effectiueness of Streptokinase for Acute Myocardial Infarction
Authors: Midgette Andre S. , Wong John B. , Beshansky Joni R. , Porath Avi , Fleming Craig , Pauker Stephen G.
Published: March 2007

Objective: To determine the effects of infarct location and of the likelihood of infarction on the cost-effectiveness of intravenous streptokinase (IVSK) for suspected acute myocardial infarction (AMI). Design: A meta-analysis of short-term survival was combined with a simple decision tree to determine marginal cost-effectiveness ratios for different infarct locations and different likelihoods of AMI (pMI). Setting: Six randomized trials comparing IVSK with conservative treatment. Patients: 31,940 patients with onset of symptoms of AMI from four to 24 hours earlier and, with the exception of one trial, electrocardiographic abnormalities. Patients with contraindications to thrombolytic treatment such as uncontrolled hypertension were excluded. Main results: If AMI is certain, treatment with IVSK has marginal cost- effectiveness ratios for each additional life saved of $9,900, $56,600, and $28,400, respec tively, for patients with anterior, inferior, and other locations of AMI. If pMI is 50%, treatment with IVSK has marginal cost-effectiveness ratios for each additional life saved of $22,700, $131,800, and $63,100, respectively, for patients with anterior, inferior, and other locations of AMI. Conclusions: The marginal cost-effectiveness ratio for IVSK therapy of inferior infarction is six times that for anterior infarction and rises steeply as the presence of AMI becomes less certain. Assuming society is willing to pay $250,000 per life saved, IVSK therapy should be given if the chance of acute anterior infarction exceeds 7%, if the chance of inferior infarction exceeds 32%, or if the chance of infarction in other locations exceeds 17%. In patients with suspected acute myocardial infarction, IVSK saves lives and is a reasonable use of societal resources. Key words: thrombolytic therapy; acute myocardial infarction; cost-effectiveness. (Med Decis Making 1994;14:108-117)
Ruling Out or Ruling In Disease with the Most sensitiue or Specific Diagnostic Test
Authors: Boyko Edward J.
Published: March 2007

Previous publications have advocated that clinicians choose the most sensitive diagnostic test to rule out disease and the most specific diagnostic test to rule in disease. This paper critically examines the validity of these recommendations. First, the author finds that following these recommendations does not lead to the highest disease probability for a positive test result (thereby best ruling in disease) or the lowest disease probability for a negative test result (thereby best ruling out disease). In general, the ability of a diagnostic test to lead to the highest (rule in) or lowest (rule out) disease probability should be judged based on likelihood ratios. Next, by comparing expected utilities, the author considers whether the most specific test leads to the best clinical outcome when a rule-in strategy is clinically advisable, i.e., when the costs of false-positive results are high, and whether the most sensitive test leads to the best clinical outcome when a rule-out strategy is clinically advisable, i.e., when the costs of false-negative results are high. The author again demonstrates that the greatest clinical utility is not always achieved by using the most specific test in a rule-in decision or the most sensitive test in a rule-out decision. Tradeoffs between sensitivity, specificity, disease probability, and utilities of correct and incorrect disease classifications by the diagnostic test must be simultaneously captured to determine which strategy maxi mizes clinical utility. Key words: diagnostic tests; utilities. (Med Decis Making 1994;14:175- 179)
The Diagnostic Value of Scoring Models for Organic and Non-organic Gastrointestinal Disease, Including the Irritable-bowel Syndrome
Authors: Starmans Richard , Muris Jean W.M. , Fijten Gerda H. , Schouten Hubert J.A. , Pop Peter , Knottnerus J. Andre
Published: March 2007

Scoring models based on history and physical examination have been developed to dis criminate patients with non-organic gastrointestinal disease from those who have organic disease. The application of these models may lead to more efficient diagnosis and prevent somatization. Although the models have high diagnostic accuracy in the population in which they have been developed, their value in other populations has not been established. In this study previously developed models were tested in validation populations defined by the original selection criteria from the studies in which the models were developed and in un selected general practice and outpatient populations. The diagnostic performances of the models are expressed in terms of odds ratio and sensitivity and specificity for the classification of patients as having organic and non-organic disease. The diagnostic performances of all the models were rather low in the validation populations. Relatively few elements of the models had independent diagnostic value. In addition, the correlation between the scoring models, expressed in Cohen's kappa, was extremely low. The diagnostic values of the scoring models were not reproduced in comparable and unselected populations. Therefore, it is concluded that the diagnostic value of such a model has little external validity. Key words: scoring models; gastrointestinal disease; validation; diagnosis; predictive validity. (Med Decis Making 1994;14:208—216)
The Influence of Education and Experience on Ethical Attitudes in Neonatal Intensive Care
Authors: Beausoleil Janet L. , Zalneraitis Edwin L. , Gregorio David I. , Healey Joseph M.
Published: March 2007

A cross-sectional survey of medical students, pediatrics residents, and neonatologists at tempted to identify the combined influence of education and experience on ethical attitudes regarding the management of infants weighing less than 750 g at birth. Of the 120 people surveyed, 94 (78%) returned usable surveys. All groups rated quality of life the most important criterion in treatment decisions. Conversely, cost was rated least important by each group. In addition, cost was rated relatively more important by the clinical medical students than by the preclinical students, residents, or neonatologists. The neonatologist was rated the most important decision maker by the neonatologists and the residents. The parents were rated most important by both groups of students. Severe mental retardation was regarded as an unacceptable quality of life by 82% of the neonatologists, 63% of the residents, 61% of the clinical students, and 48% of the preclinical students. Severe cerebral palsy was considered an unacceptable quality of life by 73% of the neonatologists, 63% of the residents, 50% of the clinical students, and only 32% of the preclinical students. Finally, the anticipated long-term outcome of extremely-low-birth-weight infants was viewed more positively by the neonatologists than by the other groups surveyed. Key words: neonatal intensive care; neonatology; extremely-low-birth-weight infants; ethics; attitudes; education. (Med Decis Making 1994;14:403-408)
A Classroom Experiential Exercise for Studying Physical Distribution Decision-Making
Authors: Morgan Fred W. , Nelson Paul T.
Published: March 2007

Experiential exercises present students with the opportunity to make business decisions within the classroom setting. Well- designed exercises provide a transition between simply reading the textbook and actually experiencing the situation on-the-job. The instructor can utilize the experiential exercise to illus trate course concepts with greater clarity and meaningfulness. This article includes a description of an experiential game for simulating physical distribution decisions. The rules for using the game are described, and some suggestions for potential users are also discussed.
Real-Time Vehicle Trajectory Supervision on the Highway
Authors: Chapuis R. , Potelle A. , Brame J.L. , Chausse F.
Published: March 2007

This article presents a method for real-time control of vehicle trajectory on a highway based on an on-board vision system using a single camera. The system has been designed to avoid damage (e.g., due to a sleepy driver). The method is based on the real-time extraction of the lateral vehicle location, which is used to determine the vehicle trajectory. Furthermore, the system is able to correct possible bad road tracking in order to have a complete autonomy. The whole system has been im plemented on a single TMS320C50 DSP-based card. Reliable results have been obtained on the highway over several hun dreds of kilometers at low and high speeds reaching more than 130 km/hr.
Ethnographic Situation' and Ethnic Movements
Authors: Albert Bruce
Published: March 2007

■ This paper analyses the changes induced in the political, ethical and epistemological parameters of classical anthropological fieldwork by the world wide emergence of indigenous political movements and related support NGOs. It looks first at the links between post-war development policies and the rise of these indigenous and indigenist organizations. It then introduces a general dis cussion about the relationships between ethno-political struggles, anthropologi cal advocacy, ethnographic research and 'participant observation'. It finally examines the conditions of intellectual independence of an engaged anthro pology and the possible heuristic potentialities of its new field perspective of 'observant participation'.
Transcending Disciplinary Boundaries
Authors: Giri Ananta Kumar
Published: March 2007

■ Modern modes of inquiry into the human condition have been charac terized by a disciplinary mode - we make sense of the world through particular, specialized and bounded disciplines. But if the rigid boundaries between disci plines have characterized the triumphant moment of the modern world, the recent moment has shown us a different picture where the rigid boundaries between disciplines are slowly breaking down and where we find more fluidity and permeability. This article provides a glimpse of this permeability. It describes a few creative experimenters of our times who, in their works, embody a trans- disciplinary conversation and create new kinds of knowledge; knowledge which stands at the alchemical meeting point of several disciplines. Building upon these experiments, this article argues that transcending disciplinary boundaries is not possible unless we understand the limitations of the discourse and institutions of modernity. Since the rigidification of boundaries of knowledge in the contem porary world owes a lot to the logic of modernity, transcending these boundaries on the way to creating knowledge and a new mode of relationship must necess arily involve critiques of modernity and discover ways out of it. This article strives to illustrate this by pointing to the limitation of the very phrase 'interdisciplinary research' to capture the simultaneous process of transcendence and immanence that is involved in this alternative process of knowledge.