The objective of this study was to evaluate physical, mechanical, and biological properties of the polydioxanone (PDO) monofilament meshes and polyglycolide (PGA) polyfilament meshes in comparison with Permacol implants. In rat experimental model, a 1.5 × 2.0 cm defect in abdominal wall was reconstructed by using the Permacol surgical implant or knitted meshes produced from either PDO monofilament, or PGA multifilament. The implant sites were assessed for the tensile strength and the extents of material resorption, host inflammatory response and host tissue replacement on days 3, 10, 30, or 60 after the surgery. The PDO and PGA meshes were rapidly pervaded by the host connective tissue with elements of skeletal muscle histogenesis. The degree of adhesions was significantly higher in the Permacol group. All of the prostheses underwent resorption, which correlated with gradual decreases in the overall tensile strength of the site and the Col1a1 gene expression level. Elevated expression of Fgf2 gene maintained longer in the PDO group, and the Mmp9 gene expression level in this group was higher than in the other groups. Gene expression levels of inflammatory cytokines were higher in the Permacol group. The foreign body giant cell numbers were lower in the PDO and Permacol groups than in the PGA group. Minimal macrophage infiltration with predominance of M2 cells was observed in the PDO group. Overall, the PDO prosthesis turned out to be significantly better than the PGA or Permacol prostheses by a number of indicators of biocompatibility and efficacy. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B: 000-000, 2018.

Background: Autopsies on COVID-19 deceased patients have many limitations due to necessary epidemiologic and preventative measures. The ongoing pandemic has caused a significant strain on healthcare systems and is being extensively studied around the world. Clinical data does not always corelate with post-mortem findings. The goal of our study was to find pathognomonic factors associated with COVID-19 mortality in 100 post-mortem full body autopsies.Materials and Methods: Following necessary safety protocol, we performed 100 autopsies on patients who were diagnosed with COVID-19 related death. The macroscopic and microscopic pathologies were evaluated along with clinical and laboratory findings.Results: Extensive coagulopathic changes are seen throughout the bodies of diseased patients. Diffuse alveolar damage is pathognomonic of COVID-19 viral pneumonia, and is the leading cause of lethal outcome in younger patients. Extrapulmonary pathology is predominantly seen in the liver and spleen. Intravascular thrombosis is often widespread and signs of septic shock are often present.Conclusion: The described pathological manifestations of COVID-19 in deceased patients are an insight into the main mechanisms of SARS-CoV-2 associated lethal outcome. The disease bears no obvious bias in severity, but seems to be more severe in some patients, hinting at genetic or epigenetic factors at play.

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Objective: Serrated colorectal lesions are a group of colonic lesions with a serrated (saw-tooth) profile of the surface epithelium and crypts and peculiar molecular and genetic developmental mechanisms that are incompletely understood. These formations cause concern due to their premalignant potential. Aim: The review is dedicated to serrated lesions of the colon and appendix. We focused on modern classification, its role in carcinogenesis, and new approaches to morphological diagnosis. Methods: A literature search was performed using PubMed, Scopus, ResearchGate, Google, MEDLINE, and ScienceDirect databases to find studies of serrated colorectal lesions related cancer published between 2000 and 2020 that address epidemiological of risk factors, underlying pathophysiological mechanism and enable our review of these factors as well molecular, genetics, and structural patterns. Results: Serrated colorectal lesions take one-third of all benign neoplasms of the colon in the pathologist’s practice. The active study of serrated lesions began in the 1900s. Terminology and diagnostic criteria were changed in the updated classification in 2019. Morphological criteria, immunohistochemical and molecular profile, endoscopic and clinical characteristics are reviewed. Conclusion: Significant efforts were made to improve our understanding and diagnostic criteria of serrated polyps of the colorectum. Very little change has occurred since the original morphologic description of preneoplastic serrated lesions in the early 2000s. More research remains needed to develop more definitive immunophenotypic and molecular biomarkers to distinguish between non-neoplastic and neoplastic serrated lesions.

Objective: The molecular mechanisms of bladder cancer development and progression are not clear. Bladder cancer is an important focus for epidemiological studies and understanding clinical implications. Goal: The primary aim of prevention is achieved by limiting exposure to non-genetic risk factors such as smoking, diet, arsenic in drinking water, or aromatic amines at work or elsewhere. Current therapies for bladder cancer are affected by tumor morphology and associated acquired genetic mutations. Methods: A literature search was performed using PubMed, Scopus, ResearchGate, Google, MEDLINE, and ScienceDirect databases to find studies of bladder cancer published between 1984 and early 2020. The focus was articles that address epidemiological risk factors and underlying pathophysiological mechanism. Articles were selected that enabled our review of these factors as well as molecular and structural patterns. Results: There are multiple views of bladder cancer. The literature offers a number of novel insights regarding the development and progression of bladder cancer and possible biomarkers that may be useful in clinical and diagnostic practice. Conclusion: There are several molecular pathways associated with bladder cancer that are frequently updated. In addition, genetic subtypes of bladder tumors are not distinguished clearly that requires future more detailed analysis.

Umbilical cord-derived multipotent mesenchymal stromal cells (UC-MMSCs) are considered as a strong candidate for cell therapy of lower limb ischemia. Sustained calf muscle ischemia with aseptic inflammatory response was induced in Sprague-Dawley rats by excision of femoral and popliteal arteries. uC-MSCs were injected into the calf muscle on day 7 after surgery. The animals were sacrificed on days 3, 10, and 30 after transplantation. Animals responded to the transplantation by temporary improvement in their locomotor function as assessed by the rota-rod performance test. Measured size of the lesions was significantly smaller in the experimental group than in the control group at all time points throughout the observation. The transplantation stimulated angiogenic processes on day 10 after transplantation. Living transplanted cells were traced for up to 30 days after transplantation, during which time they migrated to the damaged area to be partially eliminated by host macrophages; none of them differentiated into endothelial or smooth muscle cells of blood vessels. Additionally, the transplantation led to the predominance of activated pro-angiogenic and anti-inflammatory M2 macrophages by inhibiting the CD68+ macrophage infiltration and stimulating the CD206+ macrophage activation at the site of injury. A single intramuscular injection of allogeneic umbilical cord-derived mesenchymal stromal cells reproducibly facilitated recovery of structural and functional properties of surgically ischemized calf muscles in a rat. No differentiation of the transplanted cells in vivo was observed. The transplantation negatively regulated inflammation and enhanced tissue repair chiefly by modulating local patterns of macrophage activation.

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The article presents a clinical case of hypersensitivity pneumonitis complicated by a viral infection in a 72-year-old woman. The introductory part provides a concise literature review on the etiology, classification, frequency, and possible complications of hypersensitivity pneumonitis. The patient’s computed tomography (CT) lung scan showed bilateral interstitial lesions. The patient was diagnosed with idiopathic pulmonary fibrosis based on the clinical manifestations and radiological findings. The autopsy revealed morphological signs of hypersensitivity pneumonitis (obliterative bronchiolitis, moderate interstitial fibrosis with honey-combing, nonspecific interstitial pneumonia, giant multinucleated cells) and viral lung damage (exudative stage of acute respiratory distress syndrome with interalveolar edema, hyaline membranes lining the alveoli, pneumocyte desquamation, and ugly giant cells). Keywords: hypersensitivity pneumonitis, exogenous allergic alveolitis, viral infection, lungs