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PubMedDate not supplied

[Effective scabies control system in Moscow].

The analysis using the systems approach, analogue simulation, practical conclusions of the probability theory, mathematical statistical methods, programme-oriented work organization revealed and eliminated a number of neglects that had put bounds to scabies morbidity reduction among Moscovites. In 1998, the number of the foci that dermatovenereological facilities were unaware of substantially showed a 6.9-fold decrease. Therefore, the incidence of scabies reduced by 14.6% in the city in 1998. The paper presents the guidelines developed by the authors, which will ensure that the incidence rates of scabies be 25.07 per 100,000 Moscovites by 2005. It analyzes the scabies epidemiological situation among the homeless and possible measures to promote health in this group of persons.

Animals↗
PubMed2001

Risk assessment in genetics: a semi-quantitative approach.

Public awareness of genetic predisposition to diseases such as breast cancer threatens to put severe strain on genetics services. Computer-based decision support for general practitioners (GPs) has the potential to reduce unnecessary referrals, but issues of communicating about levels of risk and uncertainty must be addressed. An argumentation logic formalism can subsume both traditional probability theory and more qualitative, reason-based approaches to communicating uncertainty, and we propose that qualitative, argument-based presentation will make uncertainty information more accessible and comprehensible to both patient and GP. We describe software that uses an argumentation approach to assess genetic risk during a GP consultation and provide referral advice along with detailed qualitative explanations for its advice. The software was evaluated in real-life GP consultations in which actors played patients concerned about genetic risk, and in use by GPs evaluating simulated cases. Significant improvement in accuracy of assessment and appropriateness of referrals was found. GPs viewed the software and the qualitative reporting approach highly favourably.

Breast Neoplasms↗
PubMed2001

The structure of networks in living systems.

It is known today there are many networks existing in living systems like signal transduction, transcriptional regulation, immanence response and like so on. These networks, like all the other networks, are based on relationships between elements. In this contribution, we propose a network model of living systems. It possesses information of connections among nodes, which stand for critical elements in a network. We formulate it as a simple model of probability theory and find interesting phenomena in it.

Computational Biology↗
PubMed2005

[Perioperative mortality. Risk factors associated with anaesthesia].

Perioperative mortality associated with anaesthesia has been closely monitored throughout half of the century. The breakthrough in anaesthesia safety occurred in the 80-ties and 90-ties of the last century, when we could witness 5-folded reduction in mortality associated with anaesthesia, i.e. from 1 death:2680 operations/anaesthetic procedures (the 50-ties of the 20 h century) to 1:10,000 (and even 20-folded reduction within the ASA 1 and 2 groups of the patients--1 death:185,000 procedures). However, the more detailed analysis showed that the perioperative mortality is significantly higher, namely 1 death: approximately 500 procedures, and in the ASA 5 group of patients 1:4.5 procedures; what is more meaningful, the numbers have not been changed since 50 years. This phenomenon supports the thesis of anaesthesia safety, however, it indicates the drawbacks within the models and scoring systems evaluating operative risk. Several available scoring scales which can predict death rate, at the same time are not able to assess the extent of the other than biological risk factors. The "extra-biological risk" (i.e. process of therapy) may in some cases increase the operative risk as a whole. The value of the operative risk, as the fraction given by predicted death rate, is located between the numbers 0 and 1 (or between survival and death in the binary model of the probability theory). Recognition of the "extrabiological risk" value depends however on the high sensitivity of the scales evaluating prediction of death rate.

Anesthesia↗
PubMedDate not supplied

[Electric shock treatment of poisoning caused by animal venoms].

Poisoning through sting or bite by venomous animals constitutes a medical emergency which is potentially fatal and not easy to resolve. In this work the Authors describe the electric shock treatment (EST) to cure poisoning by animal venoms; such method has now been used for some years for this purpose in different parts of the world (Guderian et al., 1986). The Authors describe the suitability, the effectiveness of the method, the source and the type of electric current to apply; they give usage instructions and probable theory on its working mechanism: although the latter requires a more detailed and rigorous study. They wish for the usage of EST for this purpose to spread in Italy too, although fatal poisoning is rare here, and are devising a portable instrument with the right requirements.

Animals↗
PubMedDate not supplied

[The boundary ranges of the free flight of particles of gunpowder and metals in shots from a hand firearm].

On the basis of equations of external ballistics and probability theory the largest possible distances of free (independent) flight of gunshot powder and metal particles having different forms and sizes were calculated. Experimental control of the calculated data for different types of battle and sports hand fire-arms was carried out. The correspondence of the calculated data to maximal free (independent) particle flight in blank shots was stated. In experiments with cartridges equipped with bullets the distances of free particle flight were significantly lesser (by 53-65%) which may be connected with effect of gunshot projectile on the process of particle distribution. Reversed adapted formulas and calculation variants are presented.

Firearms↗
PubMed1990

[Principles of determining reference values in hematology].

A short explanation of fundamental terminology concerning reference values is presented. Criteria for formation of a reference group are discussed and the significance of standardization of blood collection and laboratory procedures is emphasized. Interpretation of reference values is founded on the probability theory and attention is directed to non-parametric statistics.

Hematologic Tests↗
PubMed1988

A multistage model of hospital bed requirements.

This article presents a model for projecting future hospital bed requirements, based on clinical judgment and basic probability theory. Clinical judgment is used to define various categories of care, including a category for patients who are inappropriately hospitalized, for a large teaching hospital with a heavy indigent and psychiatric workload. Survey results and discharge abstract data are then used to calculate expected discharges and patient days for each clinical category. These expected discharges and patient days are converted into estimated bed requirements using a simple deterministic equation. Results of this multistage model are compared with the results obtained from exercising the simple deterministic equation alone. Because the multistage model removes patients from the hospital if they are deemed inappropriately placed, this model results in the projection of 5.1 percent fewer hospital beds than the simple deterministic equation alone.

Bed Occupancy↗
PubMedDate not supplied

[Correctness of the microdosimetric approach in radiobiology].

The application of Bernoulli model to describe the response of irradiated cell populations permits to formulate the task strictly in terms of the probability theory. The important results obtained are useful in analyzing more critically the applicability of the microdosimetric approach. The well known Kellerer-Rossi and Chadwick-Leenhouts theories were shown to have very serious contradictions in their basis.

Mathematics↗
PubMed1981

Multi-channel laboratory testing and the unexpected abnormal result: a statistical myth corrected.

Multi-channel automatic analysers generate unexpected abnormal test results impacting medical economics, policy and practice. Critics caution that many such abnormal results should be expected due simply to the statistical definition of normal limits. With a test battery of n channels the probability p that a healthy individual will be within limits on all tests, each with probability s, is usually predicted p = sn. In most clinical situations, however, the assumptions upon which this formula rests are not met and it overestimates the occurrence of abnormal results. In three screening programmes involving blood chemistry batteries on 769 patients the formula gave overestimates (p less than 0.001) of the percentage of individuals with at least one abnormal result. For a battery of eight tests 33.7 percent of patients were predicted to have abnormal results but only 20.6 percent were observed, with 14 tests 51.2 percent were predicted and only 37.1 percent observed, for 17 tests 58 percent were predicted and only 33.3 percent observed. Clinical judgment, not misapplied probability theory, should guide the physician's strategy in evaluating abnormal test results.

Adult↗
PubMed1980

Aerosol deposition in the respiratory tract of the rat. Experimental results and mathematical modelling.

The deposition fraction in the respiratory tract of rats were determined experimentally using aerosol 85Srl2 in saline. The dimensions of the particles [MMD 1.63 /+- /+- 0.47 micron, Sg = 1.29] were measured by two independent methods. Rats weighing 200 g were exposed for a period of 60 min [t] in the inhalation apparatus PIANO 3 with a generator according to Lauterbach. From the volume activity [A] of 3 - 11 Bq/litre air a depot of 35-129 kBq was formed in the animals. Spirometric values measured with a modified Jäger ergospirometer were: V = 178.8 /+- 42.9 ml, VT = = 1.18 /+- 0.24 ml. f = 163.1 /+- 28.1 cycles/min. The total amount inhaled [Q] was calculated [Q = V.A.t], the deposited amount [D] was measured by a whole body counter. THe mean deposition fraction was 0.570 /+- 0.052 and was not related either to exposure time or to aerosol activity. In view of the broad validity of the conclusions for aerosols of round-shaped particles, the mean deposition fraction was determined with the help of a mathematical model according to Landahl. The theoretical values amounted to 0.609 [from 0.522 to 0.686]. The good agreement between the mean deposition fractions estimated by two independent methods indicates that on the basis of the probability theory and dimensional analysis, the mathematical model can also be used in humans for simulation deposition as one of the basis foundations for a quantitative evaluation of inhalation risk from any kind of aerosol.

Aerosols↗
PubMed1993

Probabilistic structure calculations: a three-dimensional tRNA structure from sequence correlation data.

Algorithms based on probability theory can address issues of uncertainty directly through their representational framework and their theory for data combination. In this paper, we discuss the advantages of probabilistic formulations for molecular-structure calculations, describe one implementation of such a formulation, and show its performance on a data set derived from analysis of the statistical correlations within a set of aligned transfer RNA sequences. By assigning reasonable physical interpretations to certain statistical correlations, we are able to calculate three-dimensional structures for tRNA from a random starting structure. The constraints that we use are associated with different variances, and so their effects are not uniform, and must be reconciled by a probabilistic algorithm to yield the most likely structure. As might be predicted, the uncertainty in the position for each base is a function of both the number and strength of the constraints, and is reflected in the variances in atomic position calculated by the algorithm. For example, the hinge region in the tRNA is shown to be the most uncertain. In addition, the algorithm retains information about positional covariation that is useful for understanding the relationships between different parts of the structure. These experiments also demonstrate that we can define a single-sphere representation for each base that is useful for nucleic acid structural calculations in the same way that alpha-carbon representations are useful for protein structural calculations.

Algorithms↗
PubMedDate not supplied

Excess mortality in small dialysis centers. The result of dialyzing high-risk patients.

End Stage Renal Disease Network 12 regularly collects information describing the Medicare dialysis population within its boundaries (Iowa, Nebraska, Missouri, and Kansas). Hoping to foster a regional quality improvement program, Network 12 began calculating provider specific mortality rates in 1988. These rates were extremely variable, but small dialysis units (< or = 30 patients) generally had higher mortality rates than their larger counterparts. To determine why mortality rates were inversely proportional to the number of patients treated within the center, we undertook a more intensive statistical review of patient mortality rate within the network. Actual and expected mortality rates were derived for each Network 12 dialysis center. Forty-eight percent of dialysis centers served 30 or fewer patients (small centers), and 40% had an expected mortality rate < or = 5 deaths per year. In 1989 and 1990, the crude mortality rate for dialysis centers enrolling 30 or fewer patients exceeded that of larger dialysis centers (p = 0.02). When Standardized Mortality Ratios were analyzed, this relationship disappeared (p = 0.83). Statistical review of dialysis providers is a complex process. Adjusting mortality rates for patient characteristics known to influence survival obviated the relation of dialysis unit size to patient mortality rate within Network 12. This suggests that patients were not randomly assigned to dialysis units and that small providers enrolled a disproportionate number of high risk patients. Adjusting mortality rates for endemic patient characteristics did not reduce the extreme variability noted in small mortality rates. This uncertainty, embedded in probability theory, cannot be eliminated from the statistical analysis of small samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodialysis Units, Hospital↗
PubMed1995

The role of myometrial needle biopsies in the diagnosis of adenomyosis.

OBJECTIVE: To determine the sensitivity and specificity of myometrial needle biopsies in the diagnosis of adenomyosis uteri in vitro. DESIGN: Eight needle biopsies and 8 corresponding myometrial blocks were taken from 27 hysterectomy specimens with adenomyosis and 13 specimens with adenomyosis. Adenomyosis was graded on the basis of the depth of endometrial invasion into the myometrium: grade I, adenomyosis within the inner third of the myometrium; grade II, limited to the inner two thirds; and grade III, endometrial penetration into the outer one third of the myometrium. The sensitivity of 4 and 2 biopsies was calculated by conventional probability theory. RESULTS: Taking 8 needle biopsies from each uterus yielded sensitivities for grade I, II, and III adenomyosis of 9%, 64%, and 100% respectively, but the calculated sensitivities of two biopsies, taken at random, were only 2.3%, 20%, and 56%, respectively. There were no false-positive biopsies. CONCLUSIONS: Myometrial needle biopsy is a highly specific technique for the diagnosis of adenomyosis uteri but the sensitivity is low and dependent on the number of biopsies and the depth of adenomyosis.

Biopsy, Needle↗
PubMed1993

[Quality management in the hospital--methodological comments on quality effects of two aspects of a real case].

In this article two aspects of a clinical case, known in Germany as the Marion P. case, are adapted to fit into Donabedians systematic of factors of influence on health care quality. These aspects, case-related communication between doctors on the one hand and between doctors and directly affected persons on the other, are also viewed as specific problems of decision making. It turns out that in either situation the probability theory based medical decision analysis could have been an important contribution to improve problem transparency, i.e. medical decision analysis could have been used as a tool for quality management in hospitals.

Adult↗
PubMed1977

[Clinical and morphological correlational analysis of different forms of myocardial infarct].

On the basis of a mathematical analysis carried out by a "Minsk--220" computer, the correlation between the most essential morphological changes in the coronary arteries, the peculiarities of myocardial infarction, history and its clinical manifestations were studied in 320 myocardial infarction cases (148 males and 172 females over 50 years of age) with the distinction of 276 clinical and morphological signs. The numerical assessment of the conjugation indices of the morphological changes and the clinical-laboratory data permitted to evaluate the role of each of the examined factors in the genesis of primary and secondary myocardial infarctions, their spreading in the heart muscle, and their clinical manifestations. It has been demostrated that similar changes in the coronary arteries that create a background for a relative circulatory insufficiency are realized in different forms of myocardial infarction. Relative coronary insufficiency varies widely and becomes the leading cause of myocardial ischaemia. The effect of other factors is interpreted as modifying, and some of them--as triggering. The presented correlations analysis proves the rationale of assessing each case of myocardial infarction in terms of the probability theory of patho- and morphogenesis of ischaemic heart disease.

Aged↗
PubMed1997

[Methods of investigation in clinical cardiology. X. Studies on the evaluation of diagnostic tests in cardiology].

Diagnosis is a complex cognitive process which is characterised by uncertainty. This uncertainty can be managed through specific knowledge in conjunction with probability theory. Studies evaluating diagnostic tests are the best way of building this knowledge. Studies evaluating diagnostic tests have two essential components: the gold standard and the new test. Both components, gold standard and test, are independent measurement process that can be influenced by diverse sources of variability. The comparison between diagnostic and test is essentially a hierarchical procedure. Diagnostic tests are evaluated by their sensitivity, specificity compared to a definitive gold standard. The predictive values and the likelihood ratio test are also used. Sensitivity (the proportion of true positives) and specificity (the proportion of true negatives) are values obtained from a sample and thereby can be considered as the conditional agreement between gold standard and the new test. Kappa coefficients for sensitivity and specificity are useful tools for adjusting both indices. Sensitivity and specificity are non-poblational values, they are estimates of the true values of the study population and can be affected by random error and systematic errors (bias). Confidence intervals are useful for giving an indication of the precision of the point estimates of sensitivity and specificity. A suitable sound design is required to avoiding a biased estimate of sensitivity, likelihood ratio, and predictive values. Finally a list of potential biases is given with methods for minimising these.

Cardiology↗
PubMed1992

Cognitive-experiential self-theory and subjective probability: further evidence for two conceptual systems.

Three experiments (N = 1,331) demonstrated that research findings on suspiciousness about coincidences (Miller, Turnbull, & McFarland, 1989) can be accounted for in terms of subjective probability, as predicted by cognitive-experiential self-theory (CEST) but in contrast with the norm theory (NT) account offered by Miller et al. (1989). Ss participated in a hypothetical (Experiments 1 and 2) or real (Experiment 3) lottery game in which they chose between 2 bowls offering equivalent probabilities of winning or losing but differing with respect to absolute numbers (e.g., 1 in 10 vs. 10 in 100). Responses across 4 conditions (2 probability levels x 2 outcome types) and across the 3 experiments supported predictions derived from CEST but not those derived from NT. Results are discussed in terms of 2 conceptual systems, rational and experiential, that operate by different rules of inference.

Adult↗