BACKGROUND/AIMS: Since the majority of skin diseases are known to be accompanied by structural alterations, research efforts are focused on the development of various novel diagnostic techniques capable of providing in vivo information on the skin structure. An essential parameter here is spatial resolution. In this paper we demonstrate the capabilities of optical coherence tomography (OCT) in detecting in vivo specific features of thin and thick skin. A particular focus is made on the identification of OCT patterns typical of certain pathological processes in skin, by performing parallel histological and tomographical studies. METHODS: To obtain images of the skin, we used a compact fiber OCT system developed at the Institute of Applied Physics of the Russian Academy of Sciences. A low coherence source (superluminescent diode) operated at a wavelength of 1280 nm; the output power was 0.5-2 mW. This power is low enough to conform to the ANSI safety standards for light exposure. The in-depth resolution limited by the spectral bandwidth (40-50 nm) of the probing light was approximately 20 &mgr;m. The lateral resolution determined by the probe light focusing ranged from 15 to 30 &mgr;m. In this series of experiments the maximum depth of imaging did not extend beyond 1.5 mm. Obtaining images of skin regions 2-6 mm long took 2-4 s. OCT capabilities for imaging normal skin of different localization and some skin diseases were studied in 12 healthy volunteers and 24 patients. RESULTS: OCT imaging of the skin can detect in vivo such general pathological reactions of the human body as active inflammation and necrosis. OCT is useful for in vivo diagnosis of some specific processes in the skin, including hyperkeratosis, parakeratosis and formation of intradermal cavities. OCT imaging is noninvasive and therefore allows frequent multifocal examination of skin without any adverse effects. OCT can perform monitoring of disease progress and recovery in the course of therapy. Morphometric studies, measurements of the depth and extension of skin pathology within the human body can be easily performed by OCT. CONCLUSIONS: OCT allows imaging of subsurface soft tissues with the spatial resolution of 15-20 &mgr;m, a resolution one order of magnitude higher than that provided by other clinically available noninvasive diagnostic techniques. An imaging depth of up to 1.5-2 mm, given by current OCT technology, is sufficient to examine the skin. Real time OCT imaging can provide information not only on the structure, but also on some specific features in the functional state, of tissues. OCT imaging is a noninvasive technique, i.e., OCT does not cause trauma and has no side effects since it utilizes radiation in the near infrared wavelength range at a power as low as 1 mW.

Некротизирующий саркоидный гранулематоз (НСГ) -продуктивный васкулит мелких артерий и вен с образова-нием массивных скоплений саркоидоподобных гранулем, сопровождающийся ишемическим некрозом разной сте-пени выраженности и давности. Заболевание поражает исключительно легкие. Этиология и патогенез НСГ оста-ются малоизученными из-за редкого выявления этого за-болевания, отсутствия патогномоничных лабораторных, лучевых и функциональных критериев. Согласно мирово-му опыту, основным методом диагностики НСГ остается морфологическое исследование [1][2][3][4].Термин «некротизирующий саркоидный гранулема-тоз» был впервые предложен в 1973 г. А. Liebov [5]. Автор описал 11 наблюдений пациентов, в биоптатах легких ко-торых гистологически был выявлен продуктивный васку-лит. Васкулит сопровождался наличием саркоидоподоб-ных гранулем с образованием конгломератов и некроти-ческими изменениями. При этом отсутствовала внутри-грудная лимфаденопатия, характерная для саркоидоза. У этих пациентов наступала регрессия процесса спонтан-но или после непродолжительной терапии. necrotizing sarcoid granulomatosis (nsG) belongs to productive small-vessel vasculitis with the formation of sarcoid-like granulomas, which is accompanied by ischemic necrosis of varying degrees and duration. The disease involves the lung only. The clinical symptoms of the disease are nonspecific so the latter is detected rather rarely. The main diagnostic technique is morphological examination. Immune complex inflammation develops in the vessel walls with the formation of macrophage-histiocytic granulomas that do not contain epithelioid cells. The etiology and pathogenesis of nsG remain little studied. Its differential diagnosis is mainly presented with tuberculosis, sarcoidosis, and granulomatosis with polyangiitis.

The occurrence of diffuse large B-cell lymphoma (DLBCL) in the course of Sjogren's syndrome (SS) is considered to be equally related either to the development of DLBCL de novo or to the transformation from marginal zone lymphoma (MZL). However, the question of possible clonal relationship between MZL and DLBCL in the group of SS patients remains open. Here we present the data concerning 194 patients with lymphoma complicated SS followed up at Nasonova Research Institute of Rheumatology during the last 22 years. Molecular analysis of tumor cells was performed for 6 SS patients who had developed both MZL and DLBCL. To assess clonal relationship between each of the tumor pairs immunoglobulin heavy chain (IGH) gene rearrangements were identified according BIOMED-2 protocol by means of multiplex polymerase chain reaction followed by GeneScan fragment analysis. Despite different localization MZL and DLBCL were clonally related in five tumor pairs. The median time to transformation was 11 months (range 0-78 months). MZL and DLBCL were clonally related in most cases from our cohort of SS patients. No statistically significant difference in survival between patients with DLBCL transformed from MZL and patients with de novo DLBCL was found in the cohort of SS patients investigated.

In this article, we offer a novel classification of progressive changes in the connective tissue of dermis in vulvar lichen sclerosus (VLS) relying on quantitative assessment of the second harmonic generation (SHG) signal received from formalin fixed and deparaffinized tissue sections. We formulate criteria for distinguishing four degrees of VLS development: Initial‐Mild‐Moderate‐Severe. Five quantitative characteristics (length and thickness type I Collagen fibers, Mean SHG signal intensity, Skewness and Coherence SHG signal) are used to describe the sequential degradation of connective tissue (changes in the structure, orientation, shape and density of collagen fibers) up to the formation of specific homogeneous masses. Each of the degrees has a characteristic set of quantitatively expressed features. We focus on the identification and description of early, initial changes of the dermis as the least specific. The results obtained by us and the proposed classification of the degrees of the disease can be used to objectify the dynamics of tissue changes during treatment.

Autopsy data from 80 patients who died of the COVID-19 infection were analysed. Using macro- and microscopic studies, specific features of pathological processes in various organs were identified. The obtained experimental data, along with information from literature sources, allowed conclusions to be drawn about the mechanisms of damaging internal organs and body systems, as well as assumptions to be made about individual links in the pathogenesis of COVID-19. The thanatogenesis of the disease and the main causes of death are discussed, including acute cardiopulmonary failure, acute renal failure, pulmonary thromboembolism, shock involving multiple organ failure and sepsis. The critical importance of autopsy is emphasized, which provides valuable information on the morphological substrate for this infection closely associated with possible clinical manifestations.