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The purpose of the review is to acquaint general practitioners, therapists, gastroenterologists with the possibilities of diagnosing functional disorders of the gastrointestinal tract associated with constipation, as well as to draw attention to the need for additional examination methods for a comprehensive assessment of functional disorders of the gastrointestinal tract in patients with constipation on pathogenesis.Functional constipation is an urgent problem today due to its prevalence among different age groups, a negative impact on the quality of life, as well as the variability of the clinical forms of diseases associated with this symptom. The modern diagnostic algorithm for chronic constipation consists of several stages, including the identification of signs of the disease, according to the Rome criteria of the IV revision (2016), the identification of symptoms of “red flags” and laboratory and instrumental research. It should be borne in mind that functional constipation is often based on the pathology of the anorectal zone, which is an important factor in the diagnosis and development of further therapeutic strategies. The article provides an overview of modern and promising methods for diagnosing functional disorders of defecation, taking into account functional disorders of the anorectal zone associated with constipation.Functional methods such as anorectal manometry, rectal sensory test and balloon expulsion test are the most studied and obligatory tests for an objective assessment of the sensorimotor function of the anorectal zone. In Russia, these methods are used very little, which requires extensive familiarization of practitioners with the advantages of these techniques. Knowledge and application of the presented examination algorithms will help the clinician to increase the overall diagnostic efficiency and apply the most justified tactics of managing patients with functional pathology of the digestive system associated with constipation.

The literature review gives the present-day views of the definition, etiology, pathogenesis, diagnosis, and treatment of microscopic colitis (MC). In the present view, MC is an inflammatory bowel disease of unknown etiology, which is characterized by chronic watery diarrhea, no macroscopic signs of large bowel involvement in the presence of specific pathomorphological changes. There are two major forms of MC, which are similar in its clinical picture, yet, heterogeneous in histological criteria: collagenous colitis (CC) and lymphocytic colitis (LC). As of now, the prevalence of MC is about 100 cases per 100,000 population, which is similar with that in other inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease. MC generally prevails in women aged over 50 years. The etiology and pathogenesis of MC have not fully investigated. Watery diarrhea is as a predominant pathognomonic symptom in all the patients with MC. The major histological criterion for the diagnosis of CC is subepithelial collagen lining thickening (more than 10 pm) and that for LC is higher intraepithelial lymphocyte counts (more than 20 intraepithelial lymphocytes/100 epitheliocytes). The topical glucocorticosteroid budesonide is currently the only agent, the efficacy of which has been proven in both inducing and maintaining remission in patients with MC in many clinical trials.В обзоре литературе представлены современные взгляды на дефиницию, этиологию, патогенез, диагностику и лечение микроскопического колита (МК). По современным представлениям МК - это воспалительное заболевание кишечника неизвестной этиологии, характеризующееся хронической водянистой диареей, отсутствием макроскопических признаков поражения толстой кишки при наличии специфических патоморфологических изменений. Выделяют две основные формы МК, сходные по клинической картине, однако различные по гистологическим критериям: коллагенозный колит (КК) и лимфоцитарный колит (ЛК). В настоящее время распространенность МК составляет около 100 случаев на 100 000 населения, что сопоставимо с другими воспалительными заболеваниями кишечника, такими как язвенный колит и болезнь Крона. МК преобладает у женщин, как правило, в возрасте старше 50 лет. Этиология и патогенез МК до конца не изучены. У всех пациентов, страдающих МК, доминирующим патогномоничным симптомом служит водянистая диарея. Основным гистологическим критерием диагностики КК является утолщение субэпителиальной коллагеновой выстилки (более 10 мкм), а для ЛК - повышенное количество интраэпителиальных лимфоцитов (более 20 интраэпителиальных лимфоцитов/100 эпителиоцитов). В настоящее время топический глюкокортикостероид будесонид является единственным препаратом, эффективность которого как для индукции, так и для поддержания ремиссии МК доказана во многих клинических исследованиях.

The paper analyzes an evidence base for the pharmacotherapy of irritable bowel syndrome (IBS) A large number of randomized placebo-controlled trials (RPCTs) systematized in a number of meta-analyses suggest that monotherapy regimens with spasmolytics, antidepressants, dietary fibers, polyethylene glycol, rifaximin, probiotics, and mesalamine are effective. Only some RPCTs evaluate the efficiency of combined pharmacotherapy versus placebo for IBS. Since the basis for the pathophysiology of the latter is motility and functional disorders, visceral hypersensitivity, and, probably, impaired microbiota, we anticipate that the need to use combined approaches to treating the majority of patients with IBS, by covering a few components of its pathogenesis, is relevant. Thus, to choose pharmacotherapy for IBS in each specific case is a challenge as this is determined by the form of IBS, the availability of an approved medicine on the domestic market, the indications for use, possible long-term use, high safety, and efficacy evidence drawn from RPCTs.Представлен анализ доказательной базы по фармакотерапии синдрома раздраженного кишечника (СРК). Большое число рандомизированных плацебо-контролируемых исследований (РКИ), систематизированных в ряд метаанализов, свидетельствуют об эффективности монорежимов лечения - спазмолитической терапии, антидепрессантов, пищевых волокон, полиэтиленгликоля, рифаксимина, пробиотиков и месалазина. Только отдельные РКИ оценивают эффективность комбинированной фармакотерапии СРК по сравнению с плацебо. Поскольку основа патофизиологии СРК - нарушение моторики и функции, висцеральная гиперчувствительность и, вероятно, нарушение микробиоты, мы предполагаем, что для большинства больных СРК актуальна необходимость комбинированных подходов в лечении с охватом нескольких звеньев патогенеза СРК. Таким образом, выбор фармакотерапии СРК в каждом конкретном случае является сложным решением, поскольку определяется формой СРК, доступностью апробированного лекарственного средства на внутреннем рынке, наличием показаний к применению, возможности длительного применения, высокой безопасности и свидетельств эффективности согласно результатам РКИ.

UDC 535.21:678.067 In studying the reaction of laser radiation with composite materials, it is important to determine the absorption factors, threshold of decomposition, and loss of mass of the materials investigated. A theoretical model which allows estimating these values for some composite materials based on a polyethylene matrix with different powdered fillers (Table 1) with a particle diameter of 1-20 #m is described in the present article. The results of the calculations are compared with the experimental data obtained in [1, 2]. The experimental values of the factors ,Uexpt and Rexpt from [1], obtained for radiation intensities of I 0 < 0.01 MW/cm 2 for a neodymium laser with a pulse duration of 2 msec, are reported in Table 1. Macroscopic decomposition of the materials begins, the reflection factor R decreases, the absorption factor ~ increases (by tens of times for some materials), and a crater forms on the irradiated surface of the samples with a further increase in I o. The dependences of the depth of the craters formed and specific loss of mass on the intensity of the laser radiation are reported in [2]. The proposed model of decomposition of composite material is based on the experimental data which show that absorption of radiation in the bulk of the Samples studied basically takes place on filler particles, whose heating causes decomposition of the surrounding polyethylene matrix. In this case, it is possible to estimate the dimensional absorption factor in the Bouguer--Lambert law in terms of the section cr (m 2) of absorption of light by the particles and their concentration N (m -3) in the material: = oN. (1)