Analysis of data on leukocyte surface markers for recognition of leukemia/lymphoma phenotype pattern.

OBJECTIVE: This study was designed to test the algorithm for the recognition of leukemia/lymphoma pattern, based on cell immunophenotype assessed using specific monoclonal antibodies and measured using flow cytometry. DESIGN AND METHOD: Analysis was performed by comparing phenotyping data with reference data, followed by scoring of such comparisons. Output of the recognition was designed as a report list of possible diagnoses (defined as objects in the informatic system). Reference data were compiled from the respective literature. RESULTS: From 57 blood and bone marrow samples tested in this study, accurate recognition of the real diagnosis (object) appeared on the first four places of the report list in 54 (94.7%) samples. CONCLUSION: The list of the objects recognized by the use of algorithm appeared to be helpful in making a differential diagnosis, occasionally pointing to the states that the physician had not in mind at the start of the analysis.

Medical decision making based on inductive learning method.

Medical decision making based on inductive learning has been studied in order to collect experience necessary for practical use of such methods in clinical and epidemiological work. The decision trees have been constructed by using the modified Quinlan's approach based on choosing relevant attributes according to their informativity. An inductive learning software tool, ASSISTANT Professional, has been used for experimenting. The variability in results has been studied under varying learning conditions. Two sets of data have been chosen for learning experiments: from a study on rheumatoid factors in patients with rheumatoid arthritis, and from an epidemiological investigation of aging. The results of this study indicate the necessity to determine inductive learning parameters for each particular problem. The pruning procedure is always recommended as it eliminates redundant elements in the tree. In problems with greater number of attributes, however, pruning itself is not guaranteeing satisfactory solutions. Interventions like the change of the minimal weight threshold might improve the situation. If these precautions are met, the method of inductive learning seems to be a useful guide in practical clinical and epidemiological decisions.

An algorithm for leukaemia immunophenotype pattern recognition.

Since leukaemia-specific leucocyte antigen has not been identified to date, the immunological diagnosis of leukaemia is achieved through the application of a wide set of monoclonal antibodies specific for surface markers on leukaemic cells. Thus, the interpretation of leukaemia immunophenotype seems to be a mathematically determined comparison of 'what we found' and 'what we know' about it. The objective of this study was to establish an algorithm for transformation of empirical rules into mathematical values to achieve proper decisions. Recognition of leukaemia phenotype was performed by comparison of phenotyping data with reference data, followed by scoring of such comparisons. Systematic scoring resulted in the formation of new numerical variables allocated to each state, whereas a most significant variable was described as a complex measure of compatibility. A system of recognized states was described by mathematical variables measuring the confidence of information systems, i.e. maximal, total and relative entropy. The entire algorithm was derived by matrix algebra and coded in a high-level program language. The list of the states recognized appeared to be especially helpful in differential diagnosis, occasionally pointing to states that had not been in the scientist's mind at the start of the analysis.

A microcomputer method for continuous system simulation in health care.

A method for continuous system simulation in biomedicine and health care intended for use with personal computers is described. The method is applicable to multistate deterministic models and based on the use of standard spreadsheet programs used with such computers. It includes features such as model implementation, changes of simulation parameters, execution of simulation experiments as well as tabular and graphic presentation of simulation results. The method can be used for simulation of systems in epidemiology, health-care organization and other biomedical fields where deterministic models are suitable tools for studying phenomena connected with live systems.

[Computer-assisted teaching in medical education--development of methods and supplemental materials]. / Ucenje pomocu racunala u medicinskoj edukaciji--razvoj metoda i nastavnih materijala.

A review of the elementary types of materials for the computer assisted learning (CAI--Computer Assisted Instruction) is given in this paper. It shows our initial experiences in creating the computer educational materials of the patient management simulation type, destinated for the primary care physicians. A computer simulation program "First Aid in Traffic Accident" is described as an example. A typical structure of these materials is shown. The materials had been developed using the own authoring system, a computer program which enables the teachers and other experts to create the computer educational materials independently, with the minimal help of the professional computer experts.

A study of rheumatoid factors in juvenile rheumatoid arthritis (chronic polyarthritis) by the photometric latex test.

The photometric latex test (PLT) for the detection of rheumatoid factors (RF), developed and clinically evaluated in adult rheumatoid arthritis, was applied in a study of juvenile rheumatoid arthritis (JRA). A total of 40 individuals with JRA, 27 with other collagen diseases and 24 in a control group were examined. The incidence of seropositives by PLT was 50% in JRA, 33% in collagen diseases and 17% in controls. The percentage of JRA was significantly higher than in the controls, and also higher than values in the literature claiming that only about 20% of JRA patients are seropositive. These findings were discussed concerning the diagnostic capability of PLT as compared with other serologic tests for RF. The increase in PLT titer values was found to indicate an aggravation of the inflammatory process and could help estimate the clinical stage of the disease. A follow-up of patient titer values could be of great diagnostic value. The data on serum immunoglobulins and complement fractions levels could not confirm the findings on a significant increase in JRA patients, but following of "level profiles" of each patient could add to the estimation of patient's clinical status. In cases of seropositives when other laboratory parameters did not indicate a clear transition from the chronic active to acute stage of disease, the only parameter which often showed such a transition is the RF titer determined by PLT testing, which could be of importance for a timely change of the therapy.

The photometric latex test for rheumatoid factors in patients with rheumatoid arthritis. II. Clinical evaluation.

The photometric latex test (PLT) for the detection of rheumatoid factors has been clinically evaluated. PLT titers have been closely studied in relation to clinical and laboratory parameters by means of parametric and nonparametric statistical methods. An analysis of the sensitized sheep cell test (SSC) titers has also been undertaken. The subjects comprised 377 patients with rheumatoid arthritis (RA) and 120 controls. The medical data recorded included sex, age, diagnosis, anatomical stage, functional class, duration and course of the disease, presence of the American Rheumatism Association (ARA) criteria, blood sedimentation rate, red and white blood counts, haemoglobin concentration, total protein content, serum protein levels, and SSC and PLT titers. A multivariate stepwise regression analysis with eight normally distributed variables was made. In accordance with previous findings, a significant correlation was shown to exist between the serum protein levels and the development of the RA when the anatomical stage, functional class and course of the disease were used as parameters of disease activity. In the RA patients there was also correlation between the serologic titers and the serum protein levels, and the anatomical stage, functional class and course of the disease, and the sedimentation rate, thus showing that titers can also serve as a measure of the inflammatory process. There was a significant correlation between the number of ARA criteria and the titers in the RA patients but not in the controls. The course of the disease correlated with the serum titers and other inflammatory parameters, a finding showing that the course of the disease is an important diagnostic parameter with possible prognostic value. Correlation was also demonstrated between the white blood count and the titers. It is concluded that the sedimentation rate, albumin and gamma-globulin levels, and PLT titer are the best parameters of disease activity. The titer values are not only of diagnostic importance but have prognostic value as regards the severity of the disease.

The photometric latex test for rheumatoid factors in patients with rheumatoid arthritis. I. correlation with other serologic tests.

The photometric latex test (PLT) for the detection of rheumatoid factors (RF) has been correlated with the sensitized sheep cell test (SSC) and the latex slide test (LST). A total of 377 sera from patients with rheumatoid arthritis (RA) and 120 sera from control subjects were examined. When the PLT was carried out on the native sera at a lower buffer ionic strength (0.05 M), agglutination was noted in over 99% of cases, indicating interaction of complement with human immunoglobulin bound to the latex particle surface. Although thermal inactivation eliminated most of the complement agglutination, an increase in ionic strength (0.5 M) was found to be essential for measuring only RF agglutination. The serologic data were analysed statistically by computer. A highly significant correlation was found between all serologic tests and RA sera, but there was no such correlation with the control sera. The specificity of all tests was generally over 90% and did not vary significantly, but the sensitivity varied from 52.0% to 71.1%, confirming that about one-third of all RA patients are seronegative. The tests were analysed for their total diagnostic capability. The PLT with native sera at higher ionic strenght proved to be the most sensitive, but with thermally inactivated sera it had a better diagnostic capacity. The SSC test appeared to be less sensitive and of lower diagnostic validity. Rapid LST tests were clearly inferior to PLT tests. The PLT can be used as a reliable and straightforward serologic method of diagnosis in RA, especially when carried out at a higher ionic strength and with thermally inactivated sera. It should be given preference over other serologic tests for RF and could well become standard practice in rheumatologic serology as a substitute for the SSC test.