Hydrogels catalyzed by horseradish peroxidase (HRP) serve as an efficient and effective platform for biomedical applications due to their mild reaction conditions for cells, fast and adjustable gelation rate in physiological conditions, and an abundance of substrates as water-soluble biocompatible polymers. In this review, we highlight the tunable characteristics and use of the HRP-catalyzed hydrogels and provide a brief overview of various substrates employed in the HRP system for different biomedical applications of the resultant hydrogels. In addition, we discuss and summarize the biocompatibility, possible functionalization, and biofabrication process. Finally, the future prospective of the HRP crosslinking system is highlighted with biomedical applications.

BackgroundSinusitis is an inflammation of the paranasal sinuses that can be caused by anatomic variations of the nasal cavity and paranasal sinuses. In this study we aimed to find the relationship between sinusitis and septal deviation (SeD) and concha bullosa.MethodsTwo trained resident of ENT evaluated sinus CT scans of 463 cases presenting with nasal obstruction or chronic sinusitis symptoms from April 2011 to December 2011. CT scans were checked for the presence of conchae bullosa and the degree of septal deviation. The severity of sinusitis was evaluated according to the Lund Mackay criteria. The frequency of patients with different degrees of SeD and different grades of chronic sinusitis were studied.ResultsOf 463 cases, 47% had septal deviation. Concha bullosa was seen in 16.8% of the patients in the left side and 27.6% of them in the right side. There was no significant relationship between the presence of concha bullosa and the severity of sinusitis. Also the P value of analytical tests between the severity of sinusitis, osteomeatal involvement and the degree of septal deviation was not significant. Analysis of the relationship between the presence of SeD (either to right or left) and the severity of sinusitis in different sinuses revealed no significant P value.ConclusionsBy this study, the relationship between concha bullosa in osteomeatal complex and the severity of sinusitis was not cleared. No relationship was found between the severity of sinusitis, osteomeatal involvement and the degree of septal deviation. Also SeD (either to right or left) was not found to be associated with the severity of sinusitis in different sinuses.

IntroductionInitial methods which used human tissues as reconstruction materials caused different problems including rejection, limited shapes and infection. In 1970s, PHDPE (Medpor®) was introduced by its exclusive advantageous including no donor site morbidity, easily shaped and the minimal foreign body reaction. Hereby, we report our experience of using Medpor® in facial reconstruction especially in frontal reconstruction and orbital rim with a large sample size.MethodsThis study was a prospective cohort study. Surgical techniques included using Medpor® in reconstruction of lamina papiracea (LP) (15 patients), frontal bone (15 patients), orbital rim (18 patients) and open rhinoplasty (8 patients). All interventions on LP were performed by endoscopic procedures. All frontal operations were carried out by bicoronal incision. In orbital defects, we used subciliary incision.ResultsFrom all 56 patients, 1 case had primitive neuroectodermal tumor (PNET) of maxillary sinus. In that case, reconstruction of inferior orbital rim was not successful and extrusion was occurred after radiotherapy. In rhinoplasty and other experiences no extrusion or infection were detected within the next 1 to 3 years of follow up. There were not any palpable and visible irregularities under the skin in our experiences.ConclusionsIn this study the patients did not experience any complications during the follow up periods and the satisfaction was remarkable. Gathering these data gives rise to future review studies which can provide more organized evidences for replacing classic reconstructive methods by the presented material.

The importance of tissue engineering has been established as a promising approach in treating neurodegenerative diseases. The purpose of the current study is to determine the effect of fibrin hydrogel on the differentiation of iPSC into oligodendrocyte. For this purpose, iPSCs transduced by miR‐338 expressing lentiviruses. They were treated with basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and platelet‐derived growth factor (PDGF)‐AA. The process was traced by a 6‐day treatment in a mitogen‐free medium. At the end of the process, multipolar preoligodendrocytes appeared. In comparison to tissue culture plate (TCP), MTT assay demonstrated a significant increase in the viability of cells cultured in fibrin hydrogel. SEM analysis showed cells with elongated morphology and intertwined intercellular interactions. An immunofluorescent assay confirmed the expression of oligodendrocyte markers Olig2 and O4. In comparison to TCP, real‐time PCR data indicated a significant increase in the expression of some markers such as Olig2, MBP, Sox10, and PDGFRα on cells encapsulated in fibrin hydrogel. Overall, the results suggest that fibrin hydrogel improves viability of cells and promotes the differentiation of iPSCs into preoligodendrocytes. Hence, it can be used as an appropriate option in the tissue engineering in order to treat neurodegenerative diseases. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:192–200, 2020.

Regeneration of peripheral nerve defects remained a remarkable clinical challenge. Engineered nerve conduits represent a promising strategy to improve functional recovery in peripheral nerve injury repair. However, nerve conduits require additional factors such as neurotrophic factors to create a more conducive microenvironment for nerve regeneration. Neurotrophic factors have well-demonstrated abilities to improve neurite outgrowth, making them great candidates for repairing of defected nerves. To this end, we examined the beneficial effects of repairing the transected rat sciatic nerve by loading of nerve growth factor (NGF) in nerve conduits. The PCL/Collagen/NBG conduits were interposed into the 10 mm right sciatic nerve defects. Twenty-four rats were randomly allocated into four groups: 1- nerve autograft group, 2- a nongrafted group with gap 10-mm, 3- conduit group and 4- the conduits loaded with NGF. Motor and sensory functional recovery, the evoked muscle action potential, and motor distal latency showed significant improvement in rats treated with NGF. The histology and immunohistochemistry studies revealed less fibrosis and a high level of expression of CD31 and NF-200 protein at the crush site in the Conduit + NGF group. In conclusion, the PCL/Collagen/NBG conduit loaded with NGF, which exhibited nanometer-scale features, neurotrophic activity, favorable mechanical properties and biocompatibility could improve sciatic nerve regeneration in rats.

BackgroundChronic Rhinosinusitis (CRS) is a persistent inflammatory disease affecting paranasal sinuses. CRS is categorized into two distinct subgroups defined as CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Although several immune cells are involved in the CRS pathogenesis, the role of T cells is not fully understood. The objective of the present study was to evaluate the frequency of CD4+ and CD8+ T cells and macrophages in the sinonasal mucosa of CRS patients, as well as to investigate the specific transcription factors for Th1, Th2, Th17, and Treg cells.MethodsIn this study, 15 healthy controls, 12 CRSsNP, and 23 CRSwNP patients participated. CD4+, CD8+, and CD68+ cells were investigated in the sinonasal tissues using immunohistochemistry. The expression of transcription factors related to Th subsets (T-bet, GATA3, Ror-γt, and FoxP3) was evaluated using real-time PCR. Furthermore, CRSwNP patients were defined as eosinophilic when eosinophils consisted of more than 10% of total inflammatory cells. The Kruskal–Wallis, Mann–Whitney, and Spearman tests were used in statistical analyses.ResultsThe median (range) age of the studied groups was: 32 (14–67) for CRSwNP, 28 (10–43) for CRSsNP, and 27 (17–44) for controls. The number of eosinophils in CRSwNP patients was higher than two other groups, whereas neutrophils were elevated in both CRSwNP and CRSsNP groups in comparison to controls. The frequency of CD4+ and CD8+ T cells, macrophages, and total inflammatory cells were significantly increased in CRSwNP and CRSsNP patients compared with controls. The mRNA expression of GATA3 was increased in CRSwNP patients while mRNA expression of Ror-γt was elevated in CRSsNP patients. No significant difference was observed in T-bet mRNA expression among three groups. Both CRSwNP and CRSsNP patients showed decreased FoxP3 mRNA expression in comparison to controls.ConclusionThe frequency of CD4+ and CD8+ T cells was elevated in CRS patients. In addition, we demonstrated Th2 dominance in CRSwNP patients and Th17 dominance in CRSsNP patients, implicating different mechanisms may underlie the disease. Better CRS classification and targeted therapeutic strategies may be achievable by determining the pattern of infiltrating inflammatory cells. Therefore, further experimental investigations on T cells are needed.

: Coronavirus disease 2019, known as COVID-19, was first identified in Wuhan, China, in December 2019 and became a pandemic on Mar 11, according to the World Health Organization report. In the epidemic of COVID-19, many patients admitted to hospitals for other reasons may be silent carriers of COVID-19 and have the risk of infecting medical personnel. Thus, meticulous personal protection measures should be considered in suspicious patients, especially when close contact with the patient’s airway is anticipated. We introduce two airway trauma patients suspected of COVID-19 who required emergency tracheostomy. Patient one was a 29-year-old man who suffered facial trauma following a car accident. A chest CT scan showed peripheral ground-glass opacities suggestive for COVID-19. The second patient was a young elevator mechanic who experienced maxillofacial trauma after an elevator crash. The methods of anesthesia and airway protection and safety precautions are described.

Transtympanic injections of N-acetylcysteineas a safe and inexpensive antioxidant agent seem to be an effective otoprotective strategy for the prevention of cisplatin-induced ototoxicity and for increasing the quality of life, especially in children.