Antecedents of eating disorders and muscle dysmorphia in a non-clinical sample.

Muscle Dysmorphia (MD) has recently been conceptualized as the male form of Eating Disorders (ED); although, it is not currently classified as an ED. The current study compares etiological models of MD symptomatology and ED symptomatology. It was hypothesized that sociocultural influences on appearance (SIA) would predict body dissatisfaction (BD), and that this relationship would be mediated by self-esteem (SE) and perfectionism (P); that BD would predict negative affect (NA); and that NA would predict MD and ED symptomatology. Two-hundred-forty-seven female and 101 male college students at a midsouth university completed the study. All participants completed measures assessing each of the constructs, and multiple regression analyses were conducted to test each model's fit. In both models, most predictor paths were significant. These results suggest similarity in symptomatology and etiological models between ED and MD.

Object-oriented biomedical system modelling--the language.

The paper describes a new object-oriented biomedical continuous system modelling language (OOBSML). It is fully object-oriented and supports model inheritance, encapsulation, and model component instantiation and behaviour polymorphism. Besides the traditional differential and algebraic equation expressions the language includes also formal expressions for documenting models and defining model quantity types and quantity units. It supports explicit definition of model input-, output- and state quantities, model components and component connections. The OOBSML model compiler produces self-contained, independent, executable model components that can be instantiated and used within other OOBSML models and/or stored within model and model component libraries. In this way complex models can be structured as multilevel, multi-component model hierarchies. Technically the model components produced by the OOBSML compiler are executable computer code objects based on distributed object and object request broker technology. This paper includes both the language tutorial and the formal language syntax and semantic description.

Object-oriented biomedical system modeling--the rationale.

A short tutorial and a rationale for Object-Oriented Biomedical (Continuous) System Modelling (OOBSM) are given. The paper investigates and defines what is needed in order to make the work with complex bio-medical and pathophysiological models easier, less error prone and conceptually clearer than is possible by using the existing modelling techniques. It also contains a specification of what is required in order to make such models and corresponding knowledge communicable among different research groups and in order to use such models as components in even more complex models. The work shows that hitherto available continuous system modelling languages and tools are less suitable for the construction of complex, interdisciplinary, multilevel, hierarchical models and model components and that those modelling languages do not allow for easy exchange and communication of the model knowledge between different research groups and sites. It concludes that object-oriented and distributed objects methodologies are both feasible and suitable for such modelling.

Iodine-131 therapy in sporadic nontoxic goiter.

UNLABELLED: The effect of radioiodine in the treatment of nontoxic goiter is seldom evaluated quantitatively. The aim of this study was threefold: (a) to assess the effect of 131I on goiter volume, (b) to establish a relationship between CT volume reduction and the amount of radioactivity taken up by the thyroid and (b) to assess the precision of scintigraphic thyroid volume measurements. METHODS: In 27 patients with sporadic nontoxic goiter, the thyroid volume was estimated from a [99mTc]pertechnetate scintigram. Two different models (cylinder model and surface model) were applied. The 131I dosage varied between 507 and 3700 MBq. In all patients, noncontrast CT scanning of the neck was performed before therapy and 1 yr after therapy. RESULTS: The mean CT thyroid volume before therapy was 194 +/- 138 ml. A reduction was obtained in all patients and averaged 34% +/- 17%. The volume reduction measured by CT correlated well with the amount of 131I in the thyroid (r = 0.70). In thyroids larger than 200 ml, both scintigraphic volume estimation methods were imprecise. For smaller volumes, the surface model was superior. Hypothyroidism developed in 14% of the patients. No other side effects occurred. CONCLUSION: Iodine-131 therapy for volume reduction in nontoxic goiter is a safe and effective treatment. For scintigraphic estimation of thyroid gland volumes smaller than 200 ml, the surface model is preferred.

KBSIM/FLUIDTHERAPY: a system for optimized design of fluid resuscitation in trauma.

An application of the KBSIM (Knowledge-Based SIMulation) system to the improved design of fluid resuscitation is described. The system integrates knowledge from three domains, viz. the pathophysiology of traumatized patients represented in a quantitative biodynamic model, the heuristics of fluid resuscitation of such patients as represented in 'production rules', and some 'metaknowledge' reflected in the design of a multi-window user interface. This technique of combining numerical simulation with symbolic reasoning has obvious advantages during the design process and in training, by giving the user a possibility to evaluate his measures by direct feedback from the system. This feature of the system to assist in evaluation of alternative resuscitation procedures should also be useful as a means for decision support.

KBSIM: a system for interactive knowledge-based simulation.

The KBSIM system integrates quantitative simulation with symbolic reasoning techniques, under the control of a user interface management system, using a relational database management system for data storage and interprocess communication. The system stores and processes knowledge from three distinct knowledge domains, viz. (i) knowledge about the processes of the system under investigation, expressed in terms of a Continuous System Simulation Language (CSSL); (ii) heuristic knowledge on how to reach the goals of the simulation experiment, expressed in terms of a Rule Description Language (RDL); and (iii) knowledge about the requirements of the intended users, expressed in terms of a User Interface Description Language (UIDL). The user works in an interactive environment controlling the simulation course with use of a mouse and a large screen containing a set of 'live' charts and forms. The user is assisted by an embedded 'expert system' module continuously watching both the system's behavior and the user's action, and producing alerts, alarms, comments and advice. The system was developed on a Hewlett-Packard 9000/350 workstation under the HP-Unix and HP-Windows operating systems, using the MIMER database management system, and Fortran, Prolog/Lisp and C as implementation languages. The KBSIM system has great potentials for supporting problem solving, design of working procedures and teaching related to management of highly dynamic systems.

Prediction of myocardial infarct size from early serum myoglobin observations.

Different possibilities to predict infarct size were analysed. The basic method was the fitting of a mathematical model to serial serum myoglobin concentration values from the very early phase of infarction. Correlation was performed with infarct size estimated from the complete serum curves of 53 patients. An observation period up to and including the serum peak value (on the average 6.8 h after onset) was required in order to give a well-determined value of infarct size. A correlation coefficient of r = 0.85 (n = 38) was then obtained. The serum peak concentration value of myoglobin correlated even better (r = 0.89). The initial slope of the serum curve (obtained on the average 4.3 h after onset of symptoms) also correlated well to infarct size (r = 0.80; n = 53). In conclusion, estimation of infarct size appears to be as good with the serum peak value of myoglobin as with model-based parameters. The most useful measure for early prediction of infarct size could be the initial slope of the serum curve.

Size estimation of acute myocardial infarction from serial serum myoglobin observations with due consideration of individual differences in basic kinetics.

Thirty-three consecutive patients suffering from acute myocardial infarction were studied. Serial serum myoglobin and CK-MB measurements were made, and in seven patients individual kinetic constants for myoglobin were available from previous single injection studies. A two-compartment model for myoglobin kinetics was used for infarct size estimation. Given values for the basic kinetic constants (elimination rate constant, exchange rate constants, and distribution volume), the adjustment of a flexible, parameterized 'blood-appearance rate-function', phi AMI (mg X h-1), allowed estimation of start-time (t0), peak-time (tpeak) and end-time (tend) of myoglobin inflow into blood from the infarct area, in addition to the total cumulative release (A), which was used as a measure of infarct size. Use of patient-mean values for the kinetic constants caused a mean difference in estimated 'infarct size' of 34% (n = 7). Individual estimation of the elimination rate constant from the 'final slope' of the serum myoglobin curve could neither be recommended from a theoretical point of view nor from the practical outcome of numerical calculations; the 'true' elimination rate constant is underestimated by a factor of about 10 on average. Good correlation was found between our myoglobin estimates of 'infarct size' (using patient-mean kinetic constants), and independent estimates from serial serum CK-MB data, as calculated by the use of the method by Sobel et al.. Large inter-individual variations were found in the estimated infarct parameters, a circumstance which is of special interest in evaluation of therapeutic intervention studies on AMI-patients, and in infarct size prediction calculations.

Diagnosis, size estimation and prediction of acute myocardial infarction from S-myoglobin observations. A system analysis to assess the influence of various sources of variability.

Three different ways of using S-myoglobin observations for early diagnosis of acute myocardial infarction have been investigated by computer simulation techniques, viz. classification based on (i) single determination in relation to a decision limit, (ii) the peak serum concentration value, (iii) estimated or predicted value of infarct size from serial serum concentration determinations. The results of the in numero experiments indicate that it is possible to define optimal conditions with regard to time, period and frequency of observation, as well as to assess requirements on pre-analytical/analytical variation. The optimal time for a single observation should be about 10-12 h after onset of symptoms. The influence of pre-analytical/analytical variation is not very critical in this connection and the quality requirements are achievable in the clinical chemical laboratory today (total CV about 0.10). The peak serum value has good diagnostic power, but does not provide a good index of infarct size, no matter how good the analytical quality may be. It should be possible to predict infarct size from early serial S-myoglobin observations. A coefficient of pre-analytical/analytical variation below 0.05 is then required in addition to frequent blood specimen collection from admission up to peak time of the serum concentration curve.