[Study of the structure and microflora of urethral tissues in urethral pain syndrome].

Urethral pain syndrome (UPS) is characterized by the occurrence of persistent or recurrent pain in the urethra in the absence of a confirmed infection and other obvious local pathological changes. The study of its pathogenetic aspects is important first of all for understanding the causes of the disease, to prescribe effective treatment, specific recommendations for the prevention and treatment of this disease are also absent. This paper presents the advanced experience of our research group on the study of the urethral state by the in vivo cross-polarization optical coherence tomography (CP OCT) method, and also the results of the microbiota analysis in the urethral tissues. The purpose of the study is to search for the risk factors for UPS and the character of changes in the urethral tissues, using the data of: 1) concomitant pathology, 2) structural changes in the urethral wall in UPS in comparison with chronic cystitis of bacterial etiology 3) studying the microbiota of urethral tissues. MATERIALS AND METHODS: The condition of the urethra was studied in 109 patients: 55 of them with UPS (group "US"), without clinical manifestations of inflammation; 41 - with chronic inflammation of the lower urinary tract of various origins (group "Inf"); in 14 patients with stones of the upper urinary tract without pyelonephritis, the urethra was taken as the norm (group "N"). All performed a clinical minimum of studies, also cystoscopy with the study of the bladder triangle, the neck of the bladder and the urethra by the method of in vivo tissue imaging - CP OCT. The device "OCT-1300U" with wavelength of 1300 nm is used. To determine the possible role of UPS disease background, the analysis of concomitant pathology preceding the development of UPS was performed. To analyze the relationship of changes in the urethral tissues with the composition of its microbiota, a PCR study of biopsies from the proximal segment of the urethra was performed in 13 patients with UPS. RESULTS: Qualitative comparison of the thickness and character of the OCT signal of the urethral wall layers observed using CP OCT in the studied groups of patients allowed us to establish that the state of the epithelium and connective tissue structures of the mucous membrane in patients with UPS is not the norm, changes are similar to those in chronic inflammation. Changes in the character of the OCT signal were recorded in all parts of the urethra, but in the middle third they are most pronounced and most critical. In UPS, there is a brightly pronounced reorganization of the connective tissue stroma components. Pronounced fibrosis of subepithelial structures (increased signal brightness in the cross-channel compared to the norm) with their thickening was recorded in 48.2% of cases, and thinning/lack of visualization of the epithelial layer was detected in 20.5%, and in chronic inflammation 55.5% and 40.6% of cases, respectively. According to the results of PCR, only one patient had significant total bacterial contamination of the biopsy (TB=104.7). In all other cases, the total bacterial mass of the biopsies was at the level of negative control. CONCLUSIONS: In patients with UPS, the presence of several concomitant, often chronic, diseases was revealed, which may be a premorbid background and one of the risk factors for the occurrence and maintenance of UPS. Pilot PCR studies of biopsies from the proximal segment of the urethra indicate that low values of bacterial contamination in the majority of patients with UPS do not exclude the possible role of bacteria in the development of the disease in some patients. The CP OCT method used in this study is currently the only one in vivo method of visualization of the urethral mucosa, which provides real-time images of structural changes in the epithelial (atrophy or hyperplasia) and connective tissue (active or latent inflammation with cellular infiltration or fibrosis) layers of the urethra, allowing better understanding of the pathogenesis of the disease and monitoring of therapy.

Effect of Surgical Technique on the Microstructure and Microcirculation of the Small Intestine Stump during Delayed Anastomosis: Multimodal OCT Data.

The aim of the study was to use multimodal optical coherence tomography (MM OCT) to evaluate microstructure and microcirculation in the proximal and distal sections of the intestine relative to the resected area in acute mesenteric ischemia. MATERIALS AND METHODS: The study was carried out using three groups of male Wistar rats weighing 270-435 g (n=18). Acute occlusive arterial ischemia of the small intestine was initiated in all animals. After 80-90 min, the ischemic non-viable part of the intestine was resected, and the operation was completed by stoma exteriorization (group 1, n=6), by applying purse-string sutures (group 2, obstructive resection, n=6), or by internal drainage of the proximal and distal ends of the small intestine (group 3, bypass, n=6). Relaparotomy and anastomosis formation were performed 2 days later.With the help of MM OCT at each stage of the surgical intervention, images were obtained from the serous membrane side: the intestinal wall microstructure (layers) was viewed using cross-polarization OCT (CP OCT) and the intramural circulation - using optical coherent angiography (OCA). The MM OCT images obtained from the terminal intestine sections immediately after resection and 2 days later (before the anastomosis formation) were compared between the experimental groups, as well as with the pre-ischemic data (norm). All resected sections of the intestine were then histologically examined. The MM OCT data were compared with the histological and intravital macroscopy data. RESULTS: As a result of studying the intestinal wall microstructure by in vivo CP OCT, it was found that during ostomy (group 1) and obstructive resection (group 2), the images showed signs of tissue edema and destructive changes in the mucous membrane that were confirmed histologically, while with bypass surgery (group 3), there were minimal changes as compared with the norm.According to the OCA data, on day 2 of ostomy in the proximal and distal segments of the intestine, there was a noticeable disappearance of small and medium blood vessels; mainly large arteries and veins could be visualized. Following obstructive resection (purse-string suturing) or bypass surgery, the most noticeable changes (a decrease in the number of visualized blood vessels) were observed in the distal part of the intestine. The L index calculated from OCA images and characterizing the total length of the intramural perfused vasculature, showed a statistically significant decrease during ostomy: 12.18 [10.40; 14.20] µm - in the proximal and 10.67 [7.98; 13.05] µm - in the distal section; for comparison, the L index before ischemia was 18.90 [17.98; 19.73] µm and 18.74 [17.46; 19.90] µm, respectively (p=0.0001). In obstructive resection (group 2), statistically significant differences in the L parameter were found only for the distal bowel section: 16.39 [12.37; 18.10] µm compared with 18.74 [17.46; 19.90] µm before ischemia (p=0.041). After bypass surgery (group 3), there were no significant deviations in the L index. CONCLUSION: By using MM OCT, we found that in treating the remaining sections of the intestine after its emergency resection for acute mesenteric ischemia, the type of surgical technique determines the tissue structure in the period before the delayed anastomosis is applied.The least pronounced and most balanced changes occur in the proximal and distal segments of the intestine when operated using the bypass technique. However, to recommend this type of surgery, the development of reliable, safe, and effective bypass instruments is needed.

Trans-Serosal Multimodal Optical Coherence Tomography for Visualization of Microstructure and Blood Circulation of the Small Intestine Wall.

The aim of the study was to evaluate the performance of trans-serosal multimodal OCT (MM OCT) in in vivo detecting of changes in microstructure and blood circulation of the small intestine wall caused by arteriovenous ischemia resulted from intestine strangulation. MATERIALS AND METHODS: In experiments on Wistar rats (n=22), we examined the small intestine wall in vivo using MM OCT; the access to the intestine was reached through laparotomy. The microvasculature and microstructure of the wall were studied before and after acute arteriovenous ischemia created by ligation of a small bowel segment. The results were then added with data obtained from histological and intravital microscopic examination. RESULTS: Trans-serous MM OCT allowed us to visualize the bowel wall to its entire thickness, distinguish between the serous-muscular and mucous-submucosal layers, and detect the villi and functioning blood vessels. The structures were best seen after a fat emulsion had been administered into the bowel lumen. In OCT images made in the optical coherent angiography (OCA) mode, large paired vessels (arteries and veins) and micro-vessels with a diameter of >15 µm could be seen. Most of the blood vessels were imaged in the depth range of 80-300 µm from the surface. Capillaries with a diameter of 7-10 µm were not seen, but they produced an overall bright background. In the OCA images reconstructed from a volume of 2.4×2.4×1.8 mm, the total length of the vascular bed before ischemia was 18.3 [16.6; 19.8] mm.Strangulation of the intestinal loop was associated with changes in the CP OCT picture: the villi-associated vertical pattern and shadows of blood vessels disappeared and the depth of tissue visualization in the cross-channel decreased. The optical equivalents of the serous-muscular layer were preserved; after 180±12 min of ischemia, their proportion in the intestinal wall thickness increased from 25 [18; 32] to 42 [31; 55]% (p=0.031). At that time-point, OCA images of the strangulated bowel loop looked all similar: a uniform dark background with isolated fragmentary large vessels and no signs of blood flow in the microvascular network. CONCLUSION: Trans-serous MM OCT provides for in vivo visualization of microstructures critical for surgical gastroenterology: the intestinal wall layers including villi and blood vessels of each layer, as confirmed by histological analysis. Destructive processes in the intestinal wall resulting from bowel ligation bring about optical changes, which can be detected using real-time MM OCT.

[The role of structural changes of the urinary bladder extracellular matrix in the occurrence of different grades of adverse events after radiation therapy].

AIM: To investigate the role of structural changes of the urinary bladder extracellular matrix in the occurrence of different grades of adverse events after radiation therapy. MATERIALS AND METHODS: The connective tissue matrix was studied using 126 images obtained from the histological sections of the bladder biopsy specimens of 12 patients classified according to the clinical presentation and the grades of late bladder toxicity according to RTOG/EORTC Late Radiation Morbidity Scoring Scheme. Control images of the normal bladder (n=23) were collected from the autopsy samples. We used nonlinear microscopy imaging method capturing the second harmonic generation (SHG) signal and two-photon excitation auto-fluorescence (TPEA). RESULTS: The findings of nonlinear microscopy of urinary bladder histological sections showed that the structural changes in the connective tissue differed depending on the grade of adverse events: grade II adverse events were associated with the preservation of the structure of collagen fibers and their compression, grade III adverse events caused pronounced disorganization of collagen fibers, blurring without a definite fiber direction. At the same time, in a normal bladder, the structure of collagen fibers was visualized; they had a spiral shape and in some areas were collected in bundles. Collagen fibers and bundles were loosely arranged and accompanied by elastic fibers. The findings suggest that the grade of urinary bladder radiation injury correlates with the data detected by nonlinear microscopy. DISCUSSION: The mosaic structure of radiation-induced alterations of the bladder tissue, even in the areas most affected by radiation (posterior bladder wall, bladder trigone, and bladder neck) indicates that patients with radiation-induced high-grade toxicity need comprehensive care designed to preserve the bladder functional reserves and capacity. The prevention of radiation-related adverse events before radiation therapy should be based on urologic care aimed to detect and treat chronic inflammatory diseases of the bladder and preserve its functional reserves. Another way to improve outcomes is to optimize the management of adverse events. CONCLUSION: The examination of bladder tissue specimens taken from different parts of the bladder carried out using nonlinear microscopy in the SHG and TPEA modes revealed that the degree of structural changes in the connective tissue matrix in the post-radiation period varies and correlates with the grades of the radiation bladder toxicity. The results of this study can be used to substantiate measures to prevent the onset of high-grade toxicity after radiation therapy of pelvic malignancies.

[The value of optical coherence tomography and morphometry in evaluating the peripancreatic adipose tissue in infected pancreatic necrosis]. / Znachenie opticheskoi kogerentnoi tomografii i morfometrii dlia otsenki sostoianiia parapankreaticheskoi zhirovoi kletchatki pri infitsirovannom pankreonekroze.

OBJECTIVE: To investigate the morphometric and optical coherence tomography (OCT) characteristics of the microstructure of retroperitoneal peripancreatic adipose tissue during passive drainage and active perfusion-aspiration drainage for infected pancreatic necrosis. MATERIAL AND METHODS: The authors analyzed 74 samples of peripancreatic adipose tissue obtained from 37 patients with passive (Group 1) and active perfusion-aspiration drainage (Group 2) of a focus of peripancreatitis. The tissues were examined with OCT, then fixed in a formalin solution and underwent histological examination, including morphometric one. RESULTS: The examined groups showed qualitative and quantitative differences in the tissue microstructure. In Group 1 samples, the proportion (median (upper quartile; lower quartile)) of interlobular connective tissue was 5.6 (3.9; 6.1)%; and that of adipocytes was 44.6 (41.2; 51.6)%. Necrotic tissue occupied 46.2 (35.6; 56.1)% of the area of specimens. The OCT images of necrotic tissue displayed a preponderance of unstructured regions with a high signal level while the parenchymal areas showed a cellular structured pattern. In Group 2 samples, the proportion of interlobular connective tissue was 16.2 (11.4; 19.7)%, and that of adipocytes was 68.5 (59.7; 71.2)%. At the same time, Group 2 exhibited necrosis - 14.4 (11.5; 19.2%) that was 3.2 times less than in Group 1. The OCT images of Group 2 samples showed a preponderance of cellular structured regions characteristic of the parenchyma, with pronounced stromal elements, which corresponded to the histological pattern. CONCLUSION: Active perfusion-aspiration drainage of peripancreatic adipose tissue versus passive drainage is associated with a smaller proportion of necrotic tissue (14.4% versus 46.2%; p≤0.05) and a larger proportion of a stromal vascular component (16.2% vs. 5.6%; p≤0.05). OCT could qualitatively distinguish viable fat tissue parenchyma from necrotic areas, without specially preparing the samples, which was confirmed by histomorphometric results.

[Urethral leiomyoma].

In urology practice, leiomyoma of the urinary bladder is considered a rare tumor. Urethral leiomyoma is even more unusual. This article is a case report of a very rare benign tumor originating from the smooth muscles of the urethra causing obstructive voiding in a woman.

In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography.

Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT). A spectral domain OCT system with a specially-designed oral imaging probe was used. Microvasculature visualization was based on temporal speckle variations of the full complex signal evaluated by high-pass filtering of 3D data along the slow scan axis. Angiographic image quantification demonstrated an increase of the vascular density and total length of capillary-like-vessels before visual signs or clinical symptoms of mucositis occur. Especially significant microvascular changes compared to their initial levels occurred when grade two and three mucositis developed. Further, microvascular reaction was seen to be dose-level dependent. OCT monitoring in radiotherapy offers a non-invasive, convenient, label-free quantifiable structural and functional volumetric imaging method suitable for longitudinal human patient studies, furnishing fundamental radiobiological insights and potentially providing useful feedback data to enable adaptive radiotherapy (ART).

Photodynamic therapy monitoring with optical coherence angiography.

Photodynamic therapy (PDT) is a promising modern approach for cancer therapy with low normal tissue toxicity. This study was focused on a vascular-targeting Chlorine E6 mediated PDT. A new angiographic imaging approach known as M-mode-like optical coherence angiography (MML-OCA) was able to sensitively detect PDT-induced microvascular alterations in the mouse ear tumour model CT26. Histological analysis showed that the main mechanisms of vascular PDT was thrombosis of blood vessels and hemorrhage, which agrees with angiographic imaging by MML-OCA. Relationship between MML-OCA-detected early microvascular damage post PDT (within 24 hours) and tumour regression/regrowth was confirmed by histology. The advantages of MML-OCA such as direct image acquisition, fast processing, robust and affordable system opto-electronics, and label-free high contrast 3D visualization of the microvasculature suggest attractive possibilities of this method in practical clinical monitoring of cancer therapies with microvascular involvement.

[Use of optical coherence tomography for prognosis of the severity of oral mucositis].

The results of oral mucosa monitoring by optical coherence tomography (OCT) in the course of radiochemotherapy of 18 cases of oropharyngeal cancer are discussed. Damage to the mucosa was mainly assessed using contrast characteristics deterioration and reduction of epithelial layer thickness. Significant variation in OCT image characteristics was identified vs. mucositis grade and prognostic criteria for individual mucosal radiosensitivity worked out intact contrast on day 1 of mucositis should be interpreted as a sign of relatively mild complication. Blurred contrast would indicate mucositis stage III-IV development. Numerical analysis of OCT image patterns confirmed the contribution of the endothelial blood vessels and connecting tissue to radiation-induced damage to the mucosa.

[Lavomax treatment of chronic cystitis].

Lavomax--a synthetic fluorenon compound and a classic oral low-molecular interferon inductor--was for the first time used in combined treatment of chronic recurrent cystitis. We compared clinico-immunological indices in the treatment of exacerbations of chronic cystitis in females given lavomax and treated without it. The course of treatment consisted of 10 tablets 0.125 g each, a prophylactic course--1 tablet a week for 6 weeks. A total of 60 females aged 19-80 years entered the trial. In women given lavomax it elevated leukocyte production of alpha and gamma interferon: on treatment day 17 interferon alpha rose to 31.25 pg/ml, gamma--to 27.29 pg/ml (double baseline level). Nine weeks since the start of the treatment the above indices lowered but stayed above normal values (25.84 and 24.4 pg/ml, 23.05 and 16.39 pg/ml, respectively). As an adjuvant, lavomax promoted faster elimination of cystitis symptoms: complaints disappeared in 50% patients while in the control group only in 17%). Eradication of the bacteria was achieved in 66.7% patients. In the controls it was 2 times less. Adjuvant use of lavomax in therapy of chronic cystitis reduced frequency of cystitis recurrences.