On sequential confidence estimation of parameters of stochastic dynamical systems with conditionally Gaussian noises

We consider the problem of non-asymptotical confidence estimation of linear parameters in multidimensional dynamical systems defined by general regression models with discrete time and conditionally Gaussian noises under the assumption that the number of unknown parameters does not exceed the dimension of the observed process. We develop a non-asymptotical sequential procedure for constructing a confidence region for the vector of unknown parameters with a given diameter and given confidence coefficient that uses a special rule for stopping the observations. A key role in the procedure is played by a novel property established for sequential least squares point estimates earlier proposed by the authors. With a numerical modeling example of a two-dimensional first order autoregression process with random parameters, we illustrate the possibilities for applying confidence estimates to construct adaptive predictions

Estimating the efficiency of two algorithms for segmentation of digital radiation images of test objects

A mathematical model that describes digital radiation images of test objects is presented. Two algorithms are given for automatic segmentation of digital images distorted by additive noises. The efficiency of the algorithms is estimated based on mathematical modeling

Severity evaluation of bhronic polypous rhinosinusitis based on changes of IL-1β cytokine and IL-1ra concentrations in nasal secretions

We provide the data on distribution of IL-1β and IL-1ra cytokine concentrations in nasal secretions from the patients with different forms of chronic polypous rhinosinusitis. The control group (group 1) included healthy persons. The second group consisted of patients exhibiting chronic polypous rhinosinusitis (CRS-NP), free of clinical signs of purulent inflammation in paranasal sinuses and/or bronchial asthma. The patients of group 3 were diagnosed with chronic purulent polypous rhinosinusitis (CPRS-NP). Group 4 consisted of the patients with chronic polypoid rhinosinusitis complicated by bronchial asthma (CRS-NP + BA). Cytokine concentration was determined by means of ELISA tests for all the patient groups. We have found that the local concentrations of IL-1ra and IL-1β cytokines were significantly different (p < 0.05) from the group of healthy individuals, dependent on the clinical forms of chronic polyposis. IL-1β concentrations in the group of patients with CRS-NP (No. 2) were increased 5-fold, for group of CPRS-NP patients (No. 3), these levels showed a 15.5-fold increase. In the group of patients with CRS-NP + BA (No. 4), the Il-1 levels were 13fold higher in comparison with healthy controls. The IL-1ra concentration in the group of healthy people (No. 1) was 1825.64+463.70 pg/ml. Upon development of CRS-NP (No. 2), an increase in its values up to 3646.21±263.39 pg/ml was registered. Upon development of CPRS-NP (No. 3), an increase in appropriate values up to 2305.33±282.86 pg/ml was noted, and, in cases of CRS-NP + BA, a decrease in its values to 956.15±213.02 pg/ml was observed.Meanwhile, a conflicting character was revealed for the changes in these cytokines, thus preventing their usage as an indicator of polyposis severity. At the same time, estimation of the CIL-1ra/CIL- 1β ratio in nasal secretions of the patients in groups 1, 2, 3 and 4 based on two-dimensional projection of the spatial CIL-1ra/ CIL-1β distribution provides a basis for discrimination of the patient groups. The CIL-1ra/ CIL-1β ratio as assessed for nasal secretions of patients belonging to groups 1, 2, 3, and 4 shows a general, statistically significant decrease with increasing severity of chronic polyposis (p < 0.001), thus making this parameter indiformative for intensity of the pathological process. The resulting 95% confidence intervals confirm that the cytokine ratios are promising parameter in order to estimate the efficiency of immune therapy

Study of local inflammatory response in different clinical forms of chronic polypous rhinosinusitis

Chronic rhinosinusitis (CRS) affects 5-12% of the world’s adult population. Chronic rhinosinusitis with nasal polyps (CRSwNP) accounts for 25-30% of all cases of CRS. CRSwNP-associated inflammatory process in nasal mucosa and paranasal sinuses depends on the characteristics of local immunity, including expression of a number of cytokines. The aim of this work was to investigate the parameters of local immunity in various clinical forms of CRSwNP. In this work, the concentrations of pro-inflammatory cytokines, i.e., interleukin-1β (IL-1β) and IL-8, antimicrobial function of neutrophils from the nasal cavity was evaluated, along with histological and immunohistochemical studies of polyposis tissue. The study included 4 groups of patients: a control group of practically healthy individuals, patients with CRSwNP, clinical cases with chronic purulent rhinosinusitis and nasal polyps (CPRSwNP), and patients with CRSwNP complicated by bronchial asthma (CRSwNP + BA), including the cases with asthmatic triad (CRSwNP + intolerance to NSAIDs + BA). The patients were classified on the basis of their clinical characteristics and severity of the course of the disease. Interleukin-1β (IL-1β) and IL-8 concentrations in nasal secretions were determined by enzyme-linked immunosorbent assay (ELISA). To assess functional activity of neutrophils, a lysosomal cationic test was used on the smears from mucous surface of inferior turbinate. Histological examination of the polypous tissue biopsies was performed in slices stained with Carazzi’s hematoxylin and eosin. IL-1β and IL-8 location in the polypous tissue were detected by indirect immunohistochemistry. In all groups of the patients, IL-1β and IL-8 concentrations exceeded those in the control group. The levels of IL-1β in the groups with CPRSwNP, CRSwNP + BA were significantly increased as compared with the CRSwNP group. IL-8 concentrations in the CRSwNP and CPRSwNP groups were significantly higher than in the CRSwNP + BA group. When analyzing antimicrobial function of neutrophils, the decreased average values of cytochemical coefficient were shown in CPRSwNP and CRSwNP + BA groups, compared with the control group and CRSwNP. In all clinical forms of CPMS, complex histopathological changes were observed, including leukocyte infiltration, fibrosis, edema, and collagen depositions. In addition, the integrity of epithelial layer was found to be damaged in polyposis, epithelial metaplasia is detected as well as increased mucus production. These disorders lead to a decrease in muco-ciliary clearance in nasal cavity. The most significant pathomorphological changes occur in CRSwNP + BA, especially in cases of asthmatic triad. According to immunohistochemical data, in various forms of CRSwNP, IL-1β- and IL-8-positive leukocytes, predominantly macrophages, are detected in the polypous tissue both subepithelially and in the connective tissue stroma of the polyps. Changed concentrations of pro-inflammatory cytokines in nasal secretion of the patients, altered antimicrobial activity of mucosal neutrophils, and characteristic pathomorphological disorders in polypous tissue of patients with CRSwNP are associated with severity of inflammatory process and clinical course of the disease. The results obtained are essential to understanding the mechanisms of pathogenesis in various subgroups of CRSwNP, assessing severity of the disease and efficiency of the treatment applied

Effect of immune drugs to treat acute viral nasopharyngitis

The task in treating acute nasopharyngitis (ANP) deals with reducing the disease symptoms and the risk of complications. The lack of reliable antiviral drugs makes it important to search for appropriate medicines among other pharmacotherapeutic groups.The study involves a comparative analysis of the efficiency and estimates potential: the recombinant interferon α2b and the compound containing fungal β-D-glucans used in treat ANPThe studies involved patients with ANP from 18 to 55 years old. As many as 152 people were examined including the following: 38 were practically healthy people (group 1); and 114 patients wuth ANP: 38 people (group 2) was subject to a standard therapy (vasoconstrictor nasal drops, nasal cavity irrigation using 0.1% Miramistine solution, gargling using the Furacilin solution); forty people (group 3) were administered application of intranasal interferon α2b of 105 IU, it was delivered with a spray into each nasal passage twice a day; 36 people (group 4) were administered an immunotropic drug containing β-D-glucans orally twice a day. The duration of drug administration lasted 7 days. Polymerase chain reaction (PCR) was used to identify the ANP etiological factor. Concentrations of cytokines IL-1β, IL-1ra were estimated using enzyme immunoassay (ELISA) technique. Clinical efficiency was assessed through score approach. The following symptoms were taken into account: general malaise, sore throat, character of nasal discharge, and the difficulty of nasal breathing. The results of the study were analyzed using parametric and nonparametric statistical methods. In 60.0% the nasal secretions of patients revealed RV. The distribution of cytokine concentrations in nasal secretions in group 1 indicated that the concentration of IL-1β was in the range of 20.0-25.0 pg/ml, and the concentration of IL-1ra was about 1250.0-2500.0 pg/ml. Developing ANP stimulated an increase in IL-1β concentration up to 30.0-70.0 pg/ml in nasal secretions of patients without affecting IL-1ra concentrations. On day 7 of treatment, the cytokine concentrations among the patients treated using the immunotropic drugs were the same as in the group of healthy individuals. There were no significant changes in cytokine production on day 7 in the group of patients undergoing the standard treatment. Application of proposed immunobiological medicines to ANP does not result in overproduction of proinflammatory cytokine IL-1β in nasal secretion. This confirms that these drugs are promising in the treating strategy including reduction of the risk of developing complications

ИЗУЧЕНИЕ МЕХАНИЗМОВ ФОТОИНДУЦИРОВАННОЙ ГИБЕЛИ НА МОДЕЛИ КЛЕТОК МЕЛАНОМЫ КОЖИ

The results of the experimental study of immune response of human skin malignant melanoma cells Mel 226 on photodynamic exposure are represented in the article. Photoinduced apoptosis of skin malignant melanoma was studied in vitro. The study showed that irradiation with the agent fotoditazin at dose of 0.5–2.5 µg/ml (6 and 10 min exposure 30 min before irradiation; irradiation parameters: wavelength of 662 nm, total light dose from 40 to 60 J/cm2) induced early apoptosis. The increase of the time of laser irradiation significantly accelerates the conversion of photosensitized tumor cells from early to late apoptosis.В статье представлены результаты экспериментального исследования иммунного ответа клеток меланомы кожи человека Mel 226 на фотодинамическое воздействие. Изучен фотоиндуцированный апоптоз клеток меланомы кожи in vitro. Исследования показали, что облучение с препаратом фотодитазин в концентрациях 0,5-2,5 мкг/мл (экспозиция в течение 6 и 10 мин за 30 мин до облучения; параметры облучения: длина волны 662 нм, суммарная доза облучения от 40 до 60 Дж/см2) индуцирует ранний апоптоз. Увеличение времени лазерного облучения достоверно ускоряет переход фотосенсибилизированных опухолевых клеток из ранней фазы апоп-тоза в позднюю

On sequential confidence estimation of parameters of stochastic dynamical systems with conditionally Gaussian noises

We consider the problem of non-asymptotical confidence estimation of linear parameters in multidimensional dynamical systems defined by general regression models with discrete time and conditionally Gaussian noises under the assumption that the number of unknown parameters does not exceed the dimension of the observed process. We develop a non-asymptotical sequential procedure for constructing a confidence region for the vector of unknown parameters with a given diameter and given confidence coefficient that uses a special rule for stopping the observations. A key role in the procedure is played by a novel property established for sequential least squares point estimates earlier proposed by the authors. With a numerical modeling example of a two-dimensional first order autoregression process with random parameters, we illustrate the possibilities for applying confidence estimates to construct adaptive predictions

Non-asymptotic confidence estimation of the parameters in stochastic regression models with Gaussian noises

The article considers the problem of estimating linear parameters in stochastic regression models with Gaussian noises, such as an autoregression of the first order, threshold autoregression, and some others. We propose the non-asymptotic technique for constructing a fixed-size confidence region for unknown parameters with any prescribed coverage probability. The construction makes use of some new properties of the sequential point estimates known in the literature. The results of Monte Carlo simulations for AR(1) and TAR(1) models are given. A new version of the sequential point estimate is proposed

Fixed accuracy estimation of parameters in a threshold autoregressive model

For parameters in a threshold autoregressive process, the paper proposes a sequential modification of the least squares estimates with a specific stopping rule for collecting the data for each parameter. In the case of normal residuals, these estimates are exactly normally distributed in a wide range of unknown parameters. On the base of these estimates, a fixed-size confidence ellipsoid covering true values of parameters with prescribed probability is constructed. In the i.i.d. case with unspecified error distributions, the sequential estimates are asymptotically normally distributed uniformly in parameters belonging to any compact set in the ergodicity parametric region. Small-sample behavior of the estimates is studied via simulation data

Non-asymptotic confidence estimation of the parameters in stochastic regression models with Gaussian noises

The article considers the problem of estimating linear parameters in stochastic regression models with Gaussian noises, such as an autoregression of the first order, threshold autoregression, and some others. We propose the non-asymptotic technique for constructing a fixed-size confidence region for unknown parameters with any prescribed coverage probability. The construction makes use of some new properties of the sequential point estimates known in the literature. The results of Monte Carlo simulations for AR(1) and TAR(1) models are given. A new version of the sequential point estimate is proposed