bluuebunny/crossref_metadata_2025 huggingface dataset:
Familial and developmental abnormalities of frontal lobe function and neurochemistry in schizophrenia
Authors: Deakin J.F.W. , Simpson M.D.C. , Slater P. , Hellewell J.S.E.
Published: March 2007

Structural abnormalities of the cerebral cortex in schizophrenia have been revealed by magnetic resonance imaging, although it is not clear whether these abnormalities are diffuse or local. We predicted that changes in cortical structure would result in abnormalities in biochemical markers for the glutamate system in post mortem brain, and that the pattern of neurochemical abnormalities would be a clue to the distribution and extent of pathology. A number of studies have now reported increases in biochemical and other markers of glutamatergic cell bodies and terminals in the frontal cortex in schizophrenia. These findings are consistent with the presence of an abnormally abundant glutamatergic innervation, which may be due to an arrest in the normal developmental process of synaptic elimination. In the anterior temporal cortex and hippocampus there is evidence of an asymmetric loss of glutamate terminals, and of reduced GABA function, which may be secondary to the glutamatergic deficit. Glutamate cell body markers are spared in the temporal lobe; we argue that the loss of glutamate uptake sites may reflect the loss of an extrinsic glutamatergic innervation of the polar temporal cortex which arises from the frontal cortex. These fronto-temporal projections may be vulnerable because they arise from a cytoarchitecture which has not been stabilized by remodelling during early post natal life. There have been several therapeutic studies of drugs with actions on brain glutamate systems. Based on the glutamate deficiency theories, one approach has been to enhance glutamatergic function using agonists of the N-methyl-D-aspartate-linked glycine site. However, there are no clear therapeutic effects, and some studies report aggravation of positive symptoms. This might be expected if, as our post-mortem studies suggested, there is excess glutamatergic innervation in some brain regions in schizophrenia. There is neuropsychological evidence that frontal abnormalities in schizophrenia may be genetically determined. We found that first degree relatives of schizophrenic patients were selectively impaired in tests of frontal lobe function, whereas both frontal and temporal function is impaired in patients. We concluded that the genetic predisposition to schizophrenia involves impaired frontal lobe function. Psychotic symptoms develop only when a second process results in a loss of fronto-temporal projections and leads to temporal lobe dysfunction.
Substance dependence as a compulsive behavior
Authors: Koob George F. , Rocio M. , Carrera A. , Gold Lisa H. , Heyser Charles J. , Maldonado-Irizarry Carmen , Markou Athina , Parsons Loren H. , Roberts Amanda J. , Schulteis Gery , Stinus Luis , Walker John R. , Weissenborn Ruth , Weiss Friedbert
Published: March 2007

A compulsion to take a drug combined with a loss of control in limiting intake is the defining feature of substance dependence or addiction, and is the conceptual framework for the criteria of substance dependence or addiction outlined by the World Health Organization and the American Psychiatric Association. However, defining exactly what constitutes loss of control and compulsive drug taking at the level of animal models is a daunting task, and it is clear that no validated animal model exists for the whole syndrome of addiction. The present discussion redefines loss of control as a narrowing of the behavioral repertoire toward drug-seeking behavior and suggests that there are many sources of reinforcement that contribute to this behavioral focus on drug seeking. Evidence is presented demonstrating separate animal models for many of these sources of reinforcement as well as for most of the criteria for substance dependence. Evidence is also presented showing that the brain neurochemical systems involved in processing drug reward are altered by chronic drug exposure to contribute additional sources of reinforcement. Challenges for the future involve not only elucidation of the neurobiological substrates of the different behavioral components of addiction, but better animal models of these components with which to effect such studies.
The serotonin transporter: a primary target for antidepressant drugs
Authors: Schloss Patrick , Williams D. Clive
Published: March 2007

The serotoninergic system is known to modulate mood, emotion, sleep and appetite and thus is implicated in the control of numerous behavioural and physiological functions. Decreased serotoninergic neurotransmission has been proposed to play a key role in the aetiology of depression. The concentration of synaptic serotonin is controlled directly by its reuptake into the pre-synaptic terminal and, thus, drugs blocking serotonin transport have been successfully used for the treatment of depression. In addition to tricyclic antidepressants (TCAs; e.g. imipramine) which also block noradrenaline reuptake, highly specific serotonin reuptake inhibitors (SSRIs) such as fluoxetine and paroxetine have been developed, which are increasingly prescribed for depressed patients. The mode of action of these antidepressant drugs on their direct target, the serotonin transport protein, and possible regulatory mechanisms with respect to long-term alleviation of depression, although having been investigated both neurobiologically and clinically over the last years, are not yet understood. The cloning of the cDNA encoding the serotonin transporter has allowed a more precise characterization of this protein at the molecular level. This will show how antidepressants act at this target, thereby affecting the biochemical, pharmacological and electrophysiological properties of the serotoninergic system and give an introduction of how they might exert their therapeutic effect. This review gives an overview of the recent developments in this field, discusses mechanisms of antidepressant action on this target, and also possible interactions with other components of serotoninergic neurotransmission.
Effects of bromocriptine and haloperidol on prepulse inhibition of the acoustic startle response in man
Authors: Abduljawad K.A.J. , Langley R.W. , Bradshaw C.M. , Szabadi E.
Published: March 2007

Experiments with animals have shown that D2 dopamine (DA) receptors are involved in prepulse inhibition of the acoustic startle reflex (suppression of the reflex response evoked by a loud sound by prior presentation of a low-intensity stimulus). The present experiment attempted to extend this observation to man. Twelve healthy males (18-30 years), screened for normal hearing thresholds, participated in four sessions in which they received oral doses of placebo, bromocriptine 1.25 mg (a D2 receptor agonist), haloperidol 3 mg (a D2 receptor antagonist) and combined treatment with bromocriptine 1.25 mg+haloperidol 3 mg, according to a balanced double-blind protocol. Thirty-minute electromyographic recordings from the orbicularis oculi muscle of the right eye were carried out 120 min after ingestion of haloperidol and/or 90min after ingestion of bromocriptine. Subjects received 36 40-msec sound pulses (115 dB), separated by variable intervals (mean 25 sec); in 24 of the trials the pulse was preceded by a 40-msec prepulse (75 dB in 12 trials and 85 dB in 12 trials; prepulse-pulse interval, 120 msec). The amplitude of the startle response was not significantly altered by any of the active treatments. Under the placebo condition, both 75- and 85-dB prepulses inhibited the startle response. Bromocriptine significantly attenuated this prepulse inhibition; haloperidol also produced a small but statistically significant attenuation of prepulse inhibition. Haloperidol significantly antagonized the attenuation of prepulse inhibition produced by bromocriptine. Neither drug altered self-rated alertness, physiological finger tremor, systolic or diastolic blood pressure or salivation. Bromocriptine significantly suppressed and haloperidol significantly elevated serum prolactin levels, these changes being absent when the two drugs were given in combination. The results provide evidence for the involvement of D2 DA receptors in prepulse inhibition of the startle reflex in man.
Nicotine potentiates sulpiride-induced catalepsy in mice
Authors: Zarrindast M.R. , Haeri-Zadeh F. , Zarghi A. , Lahiji P.
Published: March 2007

The effects of nicotine on sulpiride-induced catalepsy in mice were investigated. Sulpiride (12.5-100 mg/kg) induced a low degree of catalepsy in mice which was dose dependent. Nicotine (0.0001-1 mg/kg) caused an even lower degree of catalepsy. When the drugs were co-administered a much higher cataleptogenic response was obtained. The potentiation of the effect of sulpiride by nicotine was elicited by 0.5 mg/kg or higher doses of the drug. The central nicotinic receptor antagonist mecamylamine (1-3 mg/kg) and the peripheral antagonist hexamethonium (5 and 10 mg/kg) decreased the response induced by the combination of nicotine and sulpiride. Higher doses of the cholinoceptor antagonist atropine (10 mg/kg) also reduced the catalepsy induced by the drug combination. It is concluded that nicotine potentiates sulpiride-induced catalepsy through activation of cholinergic mechanism(s) and that the central nicotinic mechanism mediates nicotine's action.
Monoaminergic synapses and schizophrenia: 45 years of neuroleptics
Authors: Bennett Max R.
Published: March 2007

In 1952 Delay and Deniker introduced the first antipsychotic, chlorpromazine, into the treatment of mental patients. They subsequently defined the word 'neuroleptic' to describe drugs as different as reserpine and chlorpromazine which seemed to have similar effects on the mental life of patients. In the 1960s the hypothesis was developed, mainly due to Carlsson, that the principal mode of action of neuroleptics was to interfere with synaptic transmission mediated by dopamine (DA) in the brain. This concept was given substantial credence with the discovery by Seeman and Snyder in the 1970s that many of the neuroleptics acted as DA receptor blockers. Subsequently two different classes of DA receptor were defined on the basis of their coupling to adenylate cyclase by Kebabian. In the 1980s molecular biology led to the cloning of five different DA receptors, and at the end of this period van Tol and his colleagues cloned the D 4 DA receptor, which has been of considerable interest in the 1990s as it is greatly elevated in the brains of schizophrenics. This historical review ends with a consideration of the possibility that in addition to DA receptors, serotonin and perhaps other transmitter receptors are involved in the aetiology of schizophrenia.
The SSRI discontinuation syndrome
Authors: Haddad Peter
Published: March 2007

A characteristic selective serotonin reuptake inhibitor (SSRI) discontinuation syndrome appears to exist. It is usually mild, commences within 1 week of stopping treatment, resolves spontaneously within 3 weeks, and consists of diverse physical and psychological symptoms, the commonest being dizziness, nausea, lethargy and headache. SSRI reinstatement leads to resolution within 48 h. A transient stage of serotonin dysregulation appears central to causation with pharmacokinetic and pharmacodynamic differences accounting for the variation in incidence between the SSRIs. Discontinuation reactions are clinically relevant due to the associated morbidity, the potential for misdiagnosis and inappropriate treatment and because they may impair future antidepressant compliance. To minimize incidence, SSRIs, like other antidepressants, should be withdrawn gradually Provisional diagnostic criteria for the SSRI discontinuation syndrome are proposed. Prospective studies are required to investigate the syndrome, particularly its effects on patient care.
The Logical Necessity of Multi-Disciplinarity: a Consistent View of the World
Authors: Kline Stephen Jay
Published: March 2007

For three hundred years two conflicting views of the world (1) have provided the overall frameworks for thought in western culture. The present paper shows neither view is sufficient for human understanding of many important systems and behaviors. A third view which appears sufficient is presented. Illustrations of the third view show increased understanding is obtained in many problems.

The sufficiency of the historic views and the route to the third view are provided through discussion of the issue of multi-disciplinarity, the question of whether it is possible to base everything we know on one discipline, or, on the contrary, if there is a logical necessity for using principles and concepts from many disciplines to achieve human understanding of the world.

The present article provides three distinct proofs of the logical necessity of multi-disciplinarity. The proofs proceed via study of: (1) the hierarchical structure of proto-typical systems in various areas of human concern; (2) the use of "integrated-control-information" by life forms and human artifacts; and (3) an extension of the theory of dimensions. The three proofs interlock, confirm, and extend each other.
Research in Sts Studies
Authors: Adams Judith , Durbin Paul , Hollander Rachelle
Published: March 2007

The challenge is there: the social problems of technology--problems related to the environment, the energy crisis, traffic problems, social engineering--so discipline-spanning in their interactions with other realms of life ... are, at bottom, problems of social and political values .... They cannot be solved, in any realistic and adequate way, without the collaboration of philosopher-generalists, broad humanists, and social science generalists working with engineers and technological experts .... The more multidisciplinary technological problems become, the more important such programs [in science, technology, and society] will turn out to be. Hans Lenk, Research in Philosophy & Technology 7 (1984): 50, 52.
Clinical Guidelines for Using Two Dichotomous Tests
Authors: Hershey John C. , Cebul Randall D. , Williams Sankey V.
Published: March 2007

Building on the threshold model developed by Pauker and Kassirer for a single test, the authors describe a decision analytic model for two tests with dichotomous outcomes. The model includes ten decision strategies that differ depending on which tests are performed, whether the tests are performed together or in sequence, and the definition of a positivity criterion used to make the treatment decision when the test results disagree. Formulas derived from the model are used to compute the preferred option as a function of disease probability and to calculate test and test-treatment thresholds. General guidelines developed from the model can be used without calculation to identify relative preferences for alternative options and to predict threshold effects. Key words: decision analytic model; tests with dichotomous outcomes. (Med Decis Making 6:68-78, 1986)
Institutional Differences in Therapeutic Decision Making in the Coronary Artery Surgery Study (CASS)
Authors: Maynard Charles , Fisher Lloyd , Alderman Edwin L. , Mock Michael B. , Ringqvist Ivar , Bourassa Martial G. , Kaiser George C. , Gillespie M.J.
Published: March 2007

This article examines institutional differences in therapeutic decision making in the Coronary Artery Surgery Study (CASS). The initial decision to use medical therapy or coronary artery bypass surgery for coronary artery disease is studied. Data from the CASS registry and a survey of CASS principal investigators were used to examine the effects of institutional characteristics, individual physician characteristics, and decision making responsibility on the recommended therapy, the actual therapy, and the ratio of the observed to expected number of surgeries. The results indicated that the experience and involvement of the surgeon in the decision making process were related to actual and recommended rates of surgery. The percentage of urgent transfers from other hospitals and the percentage of surgical referrals to outside hospitals were related to the ratio of the observed to expected numbers of surgery, an adjusted rate of surgery. A major conclusion of this study is that despite the effects of certain institutional constructs, scientific criteria in the form of clinical and angio graphic data are the most important determinants of whether a patient receives coronary artery bypass surgery.
Measures of the Value of a Diagnostic Test Derived from Stochastic Thresholds
Authors: Hartz Arthur , Centor Robert
Published: March 2007

Previous indices for measuring the potential impact of a diagnostic test on a physician's management of a given patient were derived based on a fixed threshold model. The authors adapted these indices to a stochastic threshold model. In the stochastic threshold model the physician's probability of treating the patient is a function of the patient's probability of disease. From this model the authors derived the management value index (the expected effect that the test has on the physician's probability for treating the patient) and the utility value index (the expected benefit to the patient if the diagnostic test is used). Graphs of the indices versus the patient's probability of disease may be useful in teaching appropriate use of diagnostic tests.
Decision Analysis of Treatment Options in Pyriform Sinus Carcinoma
Authors: Plante Dennis A. , Piccirillo Jay F. , Sofferman Robert A.
Published: March 2007

Decision analysis was used to evaluate the current treatment options for stage III squamous cell carcinoma of the pyriform sinus (surgery, radiation therapy, and combined surgery/ radiation therapy). Using published data, a decision tree was constructed based on quality- adjusted weeks of survival. With this model the combination of surgery and postoperative radiation therapy is preferred over either primary surgery or the combination of preoperative irradiation and surgery; primary radiation therapy is least favored. The decision is quite sensitive to the augmentation in survival that postoperative radiation therapy seems to provide over primary surgery. The decision is somewhat sensitive to the operative mortality rate and to the probability of disease-free survival following surgery. Quality of life issues emerge as important variables which need to be considered when planning treatment for patients with stage III pyriform sinus carcinoma. Key words: pyriform sinus carcinoma; hypopharyngeal carcinoma; decision analysis; quality of life. (Med Decis Making 7:74-83, 1987)
Graphic and Tabular Expressions of Bayes' Theorem
Authors: Benish William A.
Published: March 2007

Bayes' theorem, as applied to the interpretation of diagnostic tests, is reexpressed as a two- step transformation. This allows for the construction of graphic and tabular expressions of this important principle. Key words: Bayes' theorem; graph; table. (Med Decis Making 7:104-106, 1987)
Clinical Reasoning and Cognitive Processes
Authors: Hershey John C. , Baron Jonathan
Published: March 2007

Expected utility theory, and the Bayesian probability theory on which it is based, form the normative basis of most work in medical decision analysis. Recent work in the psychology of judgments and decisions indicates that people do not conform to the axioms of this theory and that these deviations occur in clinical reasoning as well as in the psychology laboratory. At issue is what to do now. The authors argue that the important next steps lie at the interface between descriptive, prescriptive, and normative accounts, all of which affect each other. They point to examples in which the simplest application of supposedly normative theory seems inappropriate, and suggest ways in which the tension between normative and de scriptive models may be resolved. Key words: decision analysis; expected utility theory; clinical reasoning; cognitive processes. (Med Decis Making 7:203-211, 1987)
Eualuating Physicians' Probabilistic Judgments
Authors: Poses Roy M. , Cebul Randall D. , Centor Robert M.
Published: March 2007

Physicians increasingly are challenged to make probabilistic judgments quantitatively. Their ability to make such judgments may be directly linked to the quality of care they provide. Many methods are available to evaluate these judgments. Graphic means of assessment include the calibration curve, covariance graph, and receiver operating characteristic (ROC) curve. Statistical tools can measure the significance of departures from ideal calibration, and measure the area under ROC curve. Modeling the calibration curve using linear or logistic regression provides another method to assess probabilistic judgments, although these may be limited by failure of the data to meet the model's assumptions. Scoring rules provide indices of overall judgmental performance, although their reliability is difficult to gauge for small sample sizes. Decompositions of scoring rules separate judgmental performance into functional components. The authors provide preliminary guidelines for choosing methods for specific research in this area. Key Words: medical judgments; probabilistic judgments; ROC curves; calibration; models. (Med Decis Making 8:233-240, 1988)
The Single-cutoff Trap
Authors: Young Mark J. , Fried Lisbeth S. , Eisenberg John M. , Hershey John C. , Williams Sankey V.
Published: March 2007

Quantitative analysis of exercise electrocardiograms has been emphasized by many inves tigators. Specific problems have been found when a single cutoff is used to define a positive or a negative test: a single cutoff does not distinguish stress electrocardiography results that are slightly positive from those that are markedly positive. This may lead clinicians to un derweigh strong evidence for or against coronary artery disease. This study evaluated cli nicians' quantitative analysis of stress electrocardiograms. Two hundred and thirty-five physicians interpreted the results of mildly positive (1.2 mm ST-segment depression) and strongly pos itive (2.2 mm ST-segment depression) stress electrocardiograms. Their posttest probability estimates were too high for a mildly positive test (0.62 ± 0.02 versus actual of 0.38; p <0.001) and too low for a strongly positive test (0.77 ± 0.01 versus actual of 0.98; p <0.001). Physicians should understand decision aids and should use multiple rather than single cutoffs to interpret the results of stress electrocardiography.
Lens Model Analysis of Hemodynamic status in the critically III
Authors: Speroff Theodore , Connors Alfred F. , Dawson Neal V.
Published: March 2007

The lens model recently has been extended to consider multiple outcomes and sequential use of clinical information. The authors have used this extended model 1) to describe the relationship between clinical information and physicians' assessments of hemodynamic sta tus, 2) to describe the empirical relationship between clinical information and physiologic measures of hemodynamic status, and 3) to compare physicians' use of information with its empirical utility. Physicians prospectively provided estimates of cardiac index and pulmonary capillary wedge pressure for 440 intensive care unit patients prior to right heart catheteri zation. The correlation between physicians' estimates and measured hemodynamic status was lower than that between clinical information and hemodynamic status (0.42 versus 0.67). Only 7% of physicians' judgment was related to subsequent ancillary testing. Empirically, subsequent ancillary testing contributed 30% to the explanation of hemodynamic status. The lens model describes limitations of physician judgment in estimating left ventricular function and helps explain how patient features relate to measured hemodynamic status. Key words: lens model; social judgment theory; physician judgment; hemodynamic status. (Med Decis Making 1989;9:243-252)
Receiver Operator characteristic (ROC) Analysis without Truth
Authors: Henkelman R. Mark , Kay Ian , Bronskill Michael J.
Published: March 2007

Receiver operator characteristic (ROC) analysis, the preferred method of evaluating diag nostic imaging tests, requires an independent assessment of the true state of disease, which can be difficult to obtain and is often of questionable accuracy. A new method of analysis is described which does not require independent truth data and which can be used when several accurate tests are being compared. This method uses correlative information to estimate the underlying model of multivariate normal distributions of disease-positive and disease-negative patients. The method is shown to give results equivalent to conventional ROC analysis in a comparison of computed tomography, radionuclide scintigraphy, and magnetic resonance imaging for liver metastasis. When independent truth is available, the method can be extended to incorporate truth data or to evaluate the consistency of the truth data with the imaging data. Key words: receiver operator characteristics; diagnostic evalu ation. (Med Decis Making 1990;10:24-29)
Reducing Sick Leave Costs by shortening Waiting Periods for Elective surgery
Authors: Nord Erik
Published: March 2007

Some sick leave of patients waiting for elective surgery could be avoided if these patients were treated with less delay. One way of achieving this is to give priority to patients on sick leave. Problems of fairness that such a policy would raise might be solved by assuring that part of the production gains stemming from avoided sick leave were used to increase treat ment capacity to benefit all patients, including those not on sick leave. Another way to reduce sick leave due to waiting time is to increase supply temporarily and reduce treatment backlog without changing priorities among patient groups. If treatment thresholds are unaffected, such a temporary increase in supply will relieve all later patients of some of their waiting and render a production gain that may exceed marginal costs. If treatment thresholds are lowered as a result of waiting time's being reduced, there will still be production gains in patients benefiting by the temporary increase in supply, but in this situation the gains may cover only part of marginal costs. Key words: waiting lists; sick leave; health economics. (Med Decis Making 1990;10:95-101)
Judicial and legislative Viewpoints on Physician Misestimation of Patient Dysutilities
Authors: Mazur Dennis J.
Published: March 2007

Appellate courts, state legislatures, and ethicists have recently (post-1972) been interested- through the evolving court doctrine of informed consent—in patient-physician joint decision making. Yet these professional groups' approaches differ markedly from that of decision analysis, failing to include an explicit role for patients' rational processing of information in informed consent. In addition, these groups charge that decision analysts are misestimating patient dysutilities. This paper examines three issues: 1) in what sense(s), if any, is decision- analytic work in individualized medical decision making misestimating patient dysutilities, 2) if this misestimation is real, whether it is an example of the normative-descriptive tensions that exist in medical decision making, and 3) in what ways do the relationships between decision-analytic and judicial decision making change when informed consent is viewed in terms of contract law as opposed to tort law. This paper argues that a key link dividing these professional groups is the differing weights given to the "value of information" by decision- analytic vs. non-decision-analytic frameworks. Key words: contract law; hazards; informed consent; legal (court, judicial) decision; malpractice; medical decision making; medical ethics; medical informed consent; medical risk; negligence; professional standards; reasonable person; tort law. (Med Decis Making 1990;10:172-180)
Using Explicit Decision Rules to Manage Issues of Justice, Risk, and Ethics in Decision Analysis
Authors: Deber Raisa B. , Goel Vivek
Published: March 2007

Concepts of justice, risk, and ethics can be merged with decision analysis by requiring the analyst to specify explicitly a decision rule or sequence of rules. Decision rules are categorized by whether they consider: 1) aspects of outcome distributions beyond central tendencies; 2) probabilities as well as utilities of outcomes; and 3) means as well as ends. This formulation suggests that distribution-based decision rules could address both risk (for an individual) and justice (for the population). Rational choice under risk if choices are one-time only (vs. repeated events) or if one branch contains unlikely but disastrous outcomes might ignore probability information. Incorporating risk attitude into decision rules rather than utilities could facilitate use of multiattribute approaches to measuring outcomes. Certain ethical concerns could be addressed by prior specification of rules for allowing particular branches. Examples, including selection of polio vaccine strategies, are discussed, and theoretical and practical implications of a decision rule approach noted. Key words: decision making; utility theory; decision analysis; ethics; risk; justice. (Med Decis Making 1990;10:181-194)
The Risk of Falling in the Elderly
Authors: Fos Peter J. , McLin Carlen L.
Published: March 2007

Accidental injury resulting from falling is the leading cause of death in the elderly population. In fact, 11 % of the nation's annual injury deaths occur in this age group. A significant number of accidental deaths occur in resident institutions. A short-term risk index was constructed and validated for the purpose of predicting the risk of a fall in an elderly institutionalized population. The risk index was developed from expert insights, using Bayesian inference. A group of experts identified major risk factors that influence the chance of a fall and provided estimates of the impacts of the identified risk factors. Identification of risk factors, elicitation of experts' insights, construction of the subjective risk index, and validation of the index are discussed. Key words: Bayesian inference; risk index; falling; elderly. (Med Decis Making 1990;10:195-200)
Psychological Androgyny and Preference for Intubation in a Nypothetical Case of End-stage Lung Disease
Authors: Yarnold Paul R. , Nightingale Stephen D. , Curry Raymond H. , Martin Gary J.
Published: March 2007

Psychological androgyny theory (PAT) was employed as a model of the interpersonal (social) and task activities required of physicians for care of their patients. According to PAT, indi viduals with a large repertoire of task and social skills ("androgynous" individuals) should be optimally adaptable to contingencies reflecting varying combinations of task and social challenges. The authors examined the relationship between androgyny and preference for intubation on a patient management problem involving end-stage lung disease for 67 general internists and internal medicine housestaff from two hosptials. Results revealed a negative relationship between androgyny and preference for intubation, suggesting that androgynous and nonandrogynous physicians respond differently to complex and difficult decision-making tasks. Indirect evidence is offered to suggest that this response reflects a general tendency to utilize fewer health care resources. Discussion focuses on the need to improve the pre cision of measurement of these latent constructs. Key words: androgyny; critical care; health care; resource use. (Med Decis Making 1990;10:215-222)
Efficacy of the Stat Serum Electrolyte Panel in the Management of Older Emergency Patients
Authors: Singal Bonita M. , Hedges Jerris R. , Succop Paul A.
Published: March 2007

The serum electrolyte panel (SEP) is commonly ordered in the workup of the emergency department (ED) patient This study was done. 1) to evaluate the efficacy of the SEP in terms of the identification of clinically significant abnormals (yield) and the impact on ther apeutic plan (impact) ; 2) to evaluate the reasons that the test was ordered; and 3) to compare the expected and realized contributions of the test to patient care Pretest and posttest questionnaires were administered to physicians managing 800 ED patients ≥ 55 years old for whom SEPs were ordered. The yield of significant abnormals was 16%. Fluid and electrolyte treatment plans were modified after the SEP results became known in 35% of cases This modification was associated with a normal SEP 48% of the time. Both the yield and the impact of the SEP were related to the reason that the test was ordered. The most common reason given was "to look for an unexpected abnormality" (50%) Physicians' expectations for the contribution of the SEP to patient care decisions were greater than the contributions realized after the results were known. However, in 115 cases, the test con tributed more than expected. Physicians predicted that 13% of the tests would contribute nothing to patient care. After the results were known, they felt that 38% had made no contribution. Physicians tend to overestimate the potential impact of the SEP but are oc casionally surprised by a result that contributes more than expected. Thus, there is consid erable pretest uncertainty about treatment decisions and normal results appear to have a substantial impact. Key words serum electrolytes; efficacy; cost containment, decision mak ing; utilization; utility. (Med Decis Making 1992;12:52-59)
Reproducibility of Predictor Variables from a Validated Clinical Rule
Authors: Heckerling Paul S. , Conant Roger C. , Tape Thomas G. , Wigton Robert S.
Published: March 2007

It has been suggested that clinical prediction rules are not reproducible, and that the most important variables frequently do not appear in replicate models. The authors studied the reproducibility of a validated rule for predicting radiographic evidence of pneumonia (ROC areas for the training and validation cohorts, 0.816 and 0.821, respectively). Two hundred replicate samples of size 250 and size 500 were generated by sampling without replacement from the original training cohort of 905 patients with a 14.6% prevalence of pneumonia. Forward selection was performed among 31 candidate variables by stepwise logistic regres sion. Using as reproducibility criteria: 1) inclusion of all five variables from the original model in the original order; 2) inclusion of all five variables in any order; 3) inclusion of the first three variables; 4) inclusion of the first two variables; 5) inclusion of the first variable; and 6) inclusion of any of the five variables: 2.5%, 13.5%, 48.5%, 85.5%, 98.0%, and 100% of replicate models of sample size 500, respectively, met the criteria, whereas 0%, 0%, 16.5%, 49.0%, 71.5%, and 97.5% of models of sample size 250 met the criteria (all comparisons by sample size p < .0001 except for criteria 1 and 6, p = 0.07). Mean ROC areas in the training and validation samples were 0.829 and 0.791 for replicate models of sample size 500, and 0.831 and 0.779 for models of sample size 250. There was no significant difference in ROC areas between training and validation cohorts for 80.5% of models of sample size 500, and for 75.3% of models of sample size 250. It is concluded that the most important predictor variables from a validated rule were included in the majority of replicate models, although the rule itself was reproduced in only a small minority of cases. In addition, the replicate models demonstrated good discriminatory power, and met statistical criteria for validation in an independent testing sample in a high percentage of cases. Key words: clinical prediction rules; replicate models; validation. (Med Decis Making 1992;12:280-285)
The Beaver Dam Health Outcomes study
Authors: Fryback Dennis G. , Dasbach Erik J. , Klein Ronald , Klein Barbara E.K. , Dorn Norma , Peterson Kathy , Martin Patrica A.
Published: March 2007

The Beaver Dam Health Outcomes Study (BDHOS) is an ongoing longitudinal cohort study of health status and health-related quality of life for a random sample of adults (age range at interview was 45 to 89 years; mean = 64.1, SD = 10.8) in a community population. In a face-to-face interview lasting approximately an hour, each participant responds to several batteries of questions. Included are a history of chronic medical conditions, current medi cations, and past surgeries; the SF-36 (a general health-status questionnaire); the Quality of Well-being index; self-rated health status on a five-point scale from "excellent" to "poor"; and evaluation of current health using the method of time tradeoffs. The authors present results from 1,356 interviews on these four principal measures, reporting mean scores by sex, by age, and for persons reporting being affected by various medical conditions. They believe data from the BDHOS will provide researchers and policy makers a reference col lection of vital statistics for health-related quality of life. Additionally, the data provide a way to compare results from studies that utilize different indices from among the four principal measures of the BDHOS. Key words: health status; quality of life (health-related); population study; cohort study. (Med Decis Making 1993;13:89-102)
Confidence Bands for Receiver Operating Characteristic Curves
Authors: Guangqin Ma  , Hall W.J.
Published: March 2007

Receiver operating characteristic (ROC) curves are mapped out by the two types of errors that are generated by varying the decision threshold used to determine which subjects will be considered abnormal. Under the conventional binormal model for the ROC curve, two- sided and one-sided simultaneous confidence bands for an entire ROC curve, or for a portion of an ROC curve, are constructed by employing Working-Hotelling-type confidence bands for simple linear regression. Pointwise confidence bands are presented for comparison. The cases in which one has only asymptotically normally distributed estimates of the parameters of the ROC curve and consistent estimates of their variance-covariance matrix are em phasized. The methods extend beyond binormal models. Key words: confidence bands for linear regression; ROC curves. (Med Decis Making 1993;13:191-197)
Measuring Preferences for Health States Worse than Death
Authors: Patrick Donald L. , Starks Helene E. , Cain Kevin C. , Uhlmann Richard F. , Pearlman Robert A.
Published: March 2007

Previous research indicates that persons assigning values to ranges of health states consider some states to be worse than death. In a study of decisions regarding life-sustaining treat ments, the authors adapted and assessed existing methods for their ability to identify and quantify preferences for health states near to or worse than death in a population of well adults and nursing home residents. The cognitive burdens involved in these decisions were also evaluated. Hypothetical health states based on six attributes of functional status were constructed to describe severe constant pain, dementia, and coma. The methods of rank order, category scaling, time tradeoff, and standard gamble were adapted to quantify states worse than death. Cognitive burden was assessed using completion rates, interviewer as sessments, respondents' self-reporting, and investigators' evaluations. For both respondent groups, all methods showed similar degrees of cognitive burden for those able to complete the tasks and were similar in their ability to identify and quantify preferences. The majority of nursing home residents, however, were unable to complete or comprehend the mea surement tasks. Most respondents evaluated their current health and severe constant pain as better than death; dementia and coma were more often considered equal to or worse than death. These results indicate that respondents can and do evaluate some health states as worse than death. The authors recommend systematic inclusion of states worse than death to describe a more complete range of preference values and routine assessment of the cognitive burdens of assessment techniques to evaluate methodologies. Keywords: health status measurement; preference weights; utility measurement; health-state prefer ences; cognitive burden. (Med Decis Making 1994;14:9-18)
A Neural Network Trained to Identify the Presence of Myocardial Infarction Bases Some Decisions on Clinical Associations That Differ from Accepted Clinical Teaching
Authors: Baxt William G.
Published: March 2007

An artificial neural network trained to identify the presence of myocardial infarction has been shown to function with a high degree of accuracy. The effects on network diagnosis of some of the clinical input variables used by this network have previously been shown to be dis tributed over two distinct maxima. Analysis of the basis for this distribution by studying the specific patterns in which these variables had significantly different impacts on network diagnosis revealed that the differential impacts were due to the contexts in which the variables whose effects were bimodally distributed were placed. These contexts were defined by the values of the other input data used by the network. In a number of instances, the clinical relationships implied by these associations were divergent from prior knowledge about factors predictive of myocardial infarction. One implication of these findings is that this network, which has been shown to perform with a high degree of diagnostic accuracy, may be doing so by identifying relationships between inputted information that are divergent from accepted teaching. Key words: neural network; clinical decisions; nonlinear association. (Med Decis Making 1994;14:217-222)
Willingness to Pay
Authors: O'Brien Bernie , Viramontes Jose Luis
Published: March 2007

The development of methods to measure willingness to pay (WTP) has renewed interest in cost-benefit analysis (CBA) for the economic evaluation of health care programs. The authors studied the construct validity and test-retest reliability of WTP as a measure of health state preferences in a survey of 102 persons (mean age 62 years; 54% male) who had chronic lung disease (forced expiratory volume <70%). Interview measurements in cluded self-reported symptoms, the oxygen-cost diagram for dyspnea, Short-Form 36 for general health status, rating scale and standard gamble for value and utility of current health state relative to death and healthy lung functioning, and WTP for a hypothetical intervention offering a 99% chance of healthy lung functioning and a 1% chance of death. WTP was elicited by a simple bidding game. To test for starting-point bias, the respondents were randomly assigned to one of five starting bids. All health status and preference measurements except WTP (controlling for income) showed significant (p < 0.05) differences between disease-severity groups (mild/moderate/severe). WTP was significantly (p = 0.01) associ ated with household income, but other health status and preference measures were not. The measure most highly correlated with WTP was standard gamble (r = -0.46). There was no association between starting bid and mean WTP adjusted for income and health status. The test-retest reliability of WTP was acceptable (r = 0.66) but lower than that for the standard gamble (r = 0.82). It is concluded that: 1) large variation in WTP responses may compromise this measure's discriminant validity; 2) there is some evidence of convergent validity for WTP with preferences measured by standard gamble; 3) there was no evidence of starting point bias; 4) the test-retest reliability of WTP is comparable to those of other preference measures. Key words: willingness to pay; health state preferences; economics. (Med Decis Making 1994;14:289-297)
Where Are the Non-visiting Patients?
Authors: Wolman Eric
Published: March 2007

In a clinical trial to increase the screening of inner-city women for breast cancer, some preliminary data suggested that about 40% of the age-eligible women who had been patients at a primary-care clinic might be expected never to visit that clinic again. The distribution of time between patients' clinic visits was modeled by fitting a distribution function to data on the "time to first visit," and indicated that the true defection rate is probably around 31 to 36%. This result, which is consistent with four related observations, suggests that most of the patients who fail to visit their clinics in a year-long interval may have become clients of other clinics. This conjecture implies massive continuing exchanges of patients among clinics, and may mean that explicit outreach by mail or phone to "non-visiting clients" will add few patient contacts to those based on spontaneous clinic visits. Key words: cancer control; community medicine; intervention studies; mass screening; models, statistical; models, the oretical; patient participation, outreach. (Med Decis Making 1994;14:345-356)
Using Real World Examples to Teach Undergraduate Consumer Behavior
Authors: Schewe Charles D.
Published: March 2007

Many approaches have been used to teach consumer behavior to undergraduate students. While many difficulties in teaching such a course exist, the approach to heavy use of published real world examples to show applications of behavioral science theories and concepts has proven very successful.
Prefab Programs for Marketing Education
Authors: Good Robert E.
Published: March 2007

Mass marketing of personal computers is a reality. These computers are starting to be used by executives. Relevant marketing education must now include how to use this new tool to help solve marketing problems.

Just as math courses don't teach marketing research, computer science courses don't teach computer-aided marketing analysis. Truly, it would be a case of 'marketing myopia' for educators to proclaim that we're not in that business.

Prefab computer programs are one educational device which can make it easier to teach and easier for students to learn computer-aided marketing analysis.
The Equivalence of Second-Order Impedance Control and Proportional Gain Explicit Force Control
Authors: Volpe Richard , Khosla Pradeep
Published: March 2007

This article discusses the essential equivalence of second-order impedance control with force feedback and proportional gain explicit force control with force feedforward. This is first done analytically by reviewing each control method and showing how they mathematically correspond for constrained manipula tor control. For stiff environments the correspondence is exact. However, even for softer environments, a similar response of the system is indicated. Next, the results of an implementation of these control schemes on the CMU DD Arm II are pre sented, confirming the predictions of the analysis. These results experimentally demonstrate that proportional gain force control and impedance control, with and without dynamics compensa tion, have equivalent response to commanded force trajectories.
Fast Computation of the C-Space of Convex 2D Algebraic Objects
Authors: Kohler Markus , Spreng Michael
Published: March 2007

Collision-free paths for a robot are commonly obtained in con figuration space. The major problem with this approach is the computation of the boundary of the configuration space ob stacles. While many results have been reported for polygonal environments, the general case of arbitrary object shape has received little attention in the literature so far. This article presents a new method for tackling this problem in the case of objects for which the boundaries consist of segments of pa rameterized algebraic curves. A fast numerical algorithm that computes the boundaries of the C-space obstacles in param eterized form is developed. The major result is that initially subdividing the segments guarantees the convergence and lim its the computational costs of the applied interval-subdivision Newton method. This makes it possible to compute the exact C-space for this more general class of objects. Finally, two examples with convex objects solved by our implementation are given.