We consider the Crow-Kimura model in case of random transitions between different fitness landscapes. The epochs (system has constant in time fitness landscape) length is given by an exponential distribution. To solve the model exactly we need a large system of functional equations. We solve the model approximately at the limits of slow or fast transitions, calculating the first-order corrections via the transition rate or its inverse. We consider the case of slow transitions and find that the mean fitness equals the average fitness for the evolution on the static fitness landscapes, minus some quantity, which we call a load. While calculating the load, we speculate about the analogy with information thermodynamics. We also look at the model with few genes and identify exact transition points to the transient phase.

INTRODUCTION. The heterogeneity of the population of patients with perforated ulcers determines the need for a targeted research of the results of their treatment, including taking into account the level of comorbidity.OBJECTIVE. To study the results and develop a predictive model of surgical treatment of perforated ulcers, taking into account the comorbid status of patients.METHODS AND MATERIALS. The results of treatment of 194 patients with perforated ulcers of the stomach and duodenum were studied. Stratification of patients was carried out taking into account the Charlson-Deyo comorbidity index. The construction of prognostic models was carried out using binary logistic regression.RESULTS. Depending on the level of comorbidity, during a posteriori comparisons, the incidence of postoperative complications in the third group (46.7%, 28/60) was statistically significantly higher compared to the first (22.8%, 13/57) and second groups (16.9%, 13/77) (χ2 = 15.908, p<0.001).In a comparative analysis, a prognostic model taking into account the comorbid status of the patient predicted the development of postoperative complications and mortality with the greatest accuracy.CONCLUSION. Taking into account the comorbid status of patients with perforated ulcer makes it possible to predict with greater accuracy the development of postoperative complications of III-V degree according to Clavien-Dindo.

Aim of the study. To assess the effect of perioperative factors on the duration of postoperative inpatient treatment of patients with perforated ulcers in conditions of different comorbidity. Material and methods. A study of the results of surgical treatment with a perforated ulcer was conducted in 194 patients. Group 1 included 57 patients (29 %) with a Charlson – Deyo comorbidity index of 0–2 points, group 2–77 patients (40 %) with a comorbidity index of 3–4 and group 3–60 patients (31 %). The Charlson – Deyo comorbidity index > 4 points. Paired and multiple linear regression were used to predict the duration of postoperative treatment. Results. The duration of the postoperative period in the first group was 9 [8–10] days, in the second group – 8 [7–9] days, in the third group – 10 [7–18] days (p < 0,001). Correlation between the level of comorbidity on the Charlson – Deyo scale straight, high closeness (ρ = 0,703), statistically significant (p < 0,001). In multivariate models for all levels of comorbidity, the significant regressor of the duration of postoperative inpatient treatment was the duration of surgery and the degree of complications according to Clavien – Dindo. In addition, in group 1, the factors were total blood bilirubin and perforation diameter, in group 3 – age, blood creatinine level and perforation diameter. Conclusion. Taking into account the comorbid status in the stratification of patients makes it possible to predict the duration of inpatient treatment of patients with perforated ulcers.

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Among the unforeseen complications of fluoroscopy, there may be cases of perforation of the stomach ulcer. Fortunately, these cases are rare. In the world literature, only 16 cases are described, one way or another related to fluoroscopy. Of course, this is an insignificant figure compared to the countless thousands of patients who pass through the hands of radiologists every day.