A randomized controlled clinical trial of concentrated growth factor combined with sodium hyaluronate in the treatment of temporomandibular joint osteoarthritis.

OBJECTIVE: To investigate the effect of concentrated growth factor (CGF) combined with sodium hyaluronate (SH) on temporomandibular joint osteoarthritis (TMJOA). METHODS: Sixty patients with TMJOA who were diagnosed by cone-beam computed tomography (CBCT) between March 2020 and March 2023 at the Stomatological Hospital of Xi'an Jiaotong University were randomly divided into a control group (n = 30) and an experimental group (n = 30). The patients in the experimental group were treated with CGF + SH, and those in the control group were treated with SH only. The visual analogue scale (VAS) score indicating pain in the temporomandibular joint (TMJ) area; the Helkimo Clinical Dysfunction Index (Di); and changes in condylar CBCT at the first visit and 2 weeks, 3 months and 6 months after treatment were recorded. The CBCT data of the patients in the experimental and control groups were collected, and the three-dimensional CBCT image sequences were imported into Mimics Medical 19.0 software in DICOM format for condylar reconstruction. RESULTS: The VAS scores at 2 weeks, 3 months and 6 months after treatment were significantly lower in the experimental group than in the control group (P < 0.05), and the pain in the experimental group was significantly relieved. The Di was significantly lower in the experimental group than in the control group (P < 0.05), and the clinical function of the TMJ improved. After treatment, the CBCT score was significantly lower in the experimental group than in the control group (P < 0.05), and the condylar bone cortex was obviously repaired. Observation of the condylar bone cortex by three-dimensional reconstruction showed the same results as those obtained by CBCT. CONCLUSION: CGF combined with SH is effective in the treatment of TMJOA and can improve muscle pain, TMJ pain, Impaired TMJ function, Impaired range of movement, Pain on movement of the mandible and promote bone repair. THE REGISTRATION NUMBER (TRN): ChiCTR2400082712. THE DATE OF REGISTRATION: April 5, 2024.

Porphyromonas gingivalis promotes the progression of oral squamous cell carcinoma by activating the neutrophil chemotaxis in the tumour microenvironment.

BACKGROUND: We aimed to determine the significance of Porphyromonas gingivalis (P. gingivalis) in promoting tumour progression in the tumour microenvironment (TME) of oral squamous cell carcinoma (OSCC). METHODS: The Gene Expression Omnibus (GEO) was used to screen out the differentially expressed genes from the two datasets of GEO138206 and GSE87539. Immunohistochemistry and immunofluorescence analysis of samples, cell biological behaviour experiments, and tumour-bearing animal experiments were used to verify the results in vivo and in vitro. The mechanism was revealed at the molecular level, and rescue experiments were carried out by using inhibitors and lentiviruses. RESULTS: CXCL2 was selected by bioinformatics analysis and was found to be related to a poor prognosis in OSCC patients. Samples with P. gingivalis infection in the TME of OSCC had the strongest cell invasion and proliferation and the largest tumour volume in tumour-bearing animal experiments and exhibited JAK1/STAT3 signalling pathway activation and epithelial-mesenchymal transition (EMT). The expression of P. gingivalis, CXCL2 and TANs were independent risk factors for poor prognosis in OSCC patients. A CXCL2/CXCR2 signalling axis inhibitor significantly decreased the invasion and proliferation ability of cells and the tumour volume in mice. When lentivirus was used to block the CXCL2/CXCR2 signalling axis, the activity of the JAK1/STAT3 signalling pathway was decreased, and the phenotype of EMT was reversed. CONCLUSION: Porphyromonas gingivalis promotes OSCC progression by recruiting TANs via activation of the CXCL2/CXCR2 axis in the TME of OSCC.

Multifunctional Asymmetric Bacterial Cellulose Membrane with Enhanced Anti-Bacterial and Anti-Inflammatory Activities for Promoting Infected Wound Healing.

An asymmetric wound dressing acts as a skin-like structure serves as a protective barrier between a wound and its surroundings. It allows for the absorption of tissue fluids and the release of active substances at the wound site, thus speeding up the healing process. However, the production of such wound dressings requires the acquisition of specialized tools, expensive polymers, and solvents that contain harmful byproducts. In this study, an asymmetric bacterial cellulose (ABC) wound dressing using starch as a porogen has been developed. By incorporating silver-metal organic frameworks (Ag-MOF) and curcumin into the ABC membrane, the wound dressing gains antioxidant, reactive oxygen species (ROS) scavenging, and anti-bacterial activities. Compared to BC-based wound dressings, this dressing promotes efficient dissolution and controlled release of curcumin and silver ions. In a full-thickness skin defect model, wound dressing not only inhibits the growth of bacteria on infected wounds but also regulates the release of curcumin to reduce inflammation and promote the production of epithelium, blood vessels, and collagen. Consequently, this dressing provides superior wound treatment compared to BC-based dressing.

Modified minimally invasive surgery in reconstructing the temporomandibular joint disk by transplantation of the temporalis myofascial flap.

OBJECTIVE: The transplantation of temporalis myofascial flap (TMF) is an indispensable method to treat severe temporomandibular joint disorders with disk failure. How to select the indication and the ways of transplantation is still a challenging topic for achieving the ideal effect. We reported the new methods and follow-up results of the patients treated with pedicled TMF transplantation. METHODS: Retrospective case series was performed at Temporomandibular Joint Specialist Clinic, the First Affiliated Hospital of Xinjiang Medical University, from December 2014 to August 2022. 39 patients (50 sides) included anterior disk displacement without reduction and disk perforation who underwent discectomy and immediate reconstruction with pedicled TMF. The initial and postoperative maximum mouth opening (MMO), and pain visual analogue scale (VAS) were compared via paired t-test and Wilcoxon signed-rank sum test, respectively. RESULTS: The average of follow-up time was 30.07 months. The reconstructed temporomandibular joints basically achieved stable occlusion, good function, and satisfactory effect. The patients displayed a remarkable reduction of VAS score of pain, and improvement of the MMO compared with that before operation (P <  0.001). MR scanning revealed the grafts in joint space showed band-shaped soft tissue density of medium signal and had the clear edges, without interruption and fragment. CONCLUSION: Reconstruction of the temporomandibular joint disk by transplantation of the TMF applying modified minimally invasive surgery was a feasible method, which could improve the function of joints and prevent adhesion, without obvious complications in donor region.

Association of HMGB1 levels in synovial fluid with the severity of temporomandibular joint osteoarthritis.

BACKGROUND: HMGB1 usually serves as a damage-associated molecular pattern (DAMP) molecule (also known as alarmin) that regulates the inflammatory and immune responses via different receptors or direct uptake. Numerous studies have reported the association between HMGB1 and inflammatory diseases; however, its role in temporomandibular joint (TMJ) osteoarthritis (OA) has not been elucidated. In this retrospective study, we aimed to investigate HMGB1 levels in the synovial fluid (SF) in patients with TMJOA and TMID, their correlation with TMJOA and TMID severity, and the therapeutic effect of sodium hyaluronate (hyaluronic acid, HA) on TMJOA. METHODS: SF samples were analyzed for 30 patients with TMJ internal derangement (TMJID) and TMJOA, along with visual analog scale (VAS) scores, radiographic stages, and mandibular functional limitations. The SF levels of HMGB1, IL-1ß, IL-18, PGE2, RAGE, TLR4, and iNOS were determined via an enzyme-linked immunosorbent assay. To evaluate the therapeutic effects of HA, pre-treatment and post-treatment clinical symptoms were also compared in patients of the TMJOA group who had received an intra-articular injection of HA. RESULTS: VAS and Jaw Functional Limitation Scale (JFLS) scores were significantly higher in the TMJOA group than in the TMNID group, as were SF levels of HMGB1, TLR4, IL-1ß, IL-18, PGE2, and iNOS. The synovial HMGB1 level was positively correlated with the VAS score (r = 0.5512, p = 0.0016) and mandibular functional limitations (r = 0.4684, p = 0.0054). The cut-off value for the HMGB1 level as a diagnostic biomarker was 986.8 pg/ml. The SF level of HMGB1 yielded an area under the curve value (AUC) of 0.8344 for predicting TMJOA. HA alleviated TMJ disorders by significantly reducing the VAS score and improving the maximum extent of mouth opening in both the TMJID and TMJOA groups (p < 0.05). Moreover, patients in both the TMJID and TMJOA groups exhibited significant improvement in the JFLS score following HA treatment. CONCLUSIONS: Our results indicate that HMGB1 is a potential marker for predicting the severity of TMJOA. Intra-articular HA injection exerts a positive therapeutic effect on TMJOA; however, further investigations are warranted to validate its therapeutic effect in the late phase of visco-supplementation treatment.

A pilot investigation of condylar position and asymmetry in patients with unilateral posterior scissors-bite malocclusion based on three-dimensional reconstructive imaging technique.

OBJECTIVE: Unilateral posterior scissors-bite (uPSB) malocclusion is common clinically. This study aimed to investigate the condylar morphological alterations and condyle-fossa relationship in patients with uPSB, through cone beam computed tomography (CBCT) and three-dimensional reconstructive imaging technique. METHODS: A retrospective study was designed to comparatively analyze 95 patients with uPSB between July 2016 and December 2021. They were divided into three subgroups: 12 to 20, 21 to 30, and ≥ 31 years, according the age distribution. The morphological parameters regarding condyle, fossa, and joint space after three-dimensional reconstruction were measured and analyzed by a series of digital software. SPSS 26.0 software package was performed for statistical analysis on data sets, using paired t-test, one-way analysis of variance, Wilcoxon signed-rank sun test, Kruskal-Wallis H test, and Bonferroni correction. RESULTS: The condylar volume (CV) of scissors-bite side was greater than that of the non-scissors-bite side (CV A = 1740.68 ± 559.80 mm3 > CV N = 1662.25 ± 524.88 mm3, P = 0.027). So was the condylar superficial area (CSA) (CSA A = 818.71 ± 186.82 mm2 > CSA N = 792.63 ± 173.44 mm2, P = 0.030), and the superior joint space (SJS) [SJS A = 2.46 (1.61, 3.68) mm) > SJS N = 2.01 (1.55, 2.87) mm), P = 0.018], and the anterior joint space (AJS) (AJS A = 3.94 ± 1.46 mm > AJS N = 3.57 ± 1.30 mm, P = 0.017). The constituent ratios of the different parts of the bilateral condyles were 23% on the posterior slope, 21% on the top, 20% on the anterior slope, 19% on the lateral slope and 17% on the medial slope, respectively. CONCLUSION: Due to long-term abnormal occlusion of uPSB, the pathological bite force in temporomandibular joint would cause changes in the shape of the condyle. Among them, CV, CSA, SJS and AJS had significant changes in the scissors-bite status, which has the greatest damage to the posterior slope of the condyloid process.

Effects of osseous structure based on three-dimensional reconstructive imaging evaluation in the assessment of temporomandibular joint disc position.

OBJECTIVES: This pilot morphological study aimed to investigate the association between anterior disc displacement (ADD) and the status of the mandibular condyle and articular fossa. MATERIALS AND METHODS: Thirty-four patients were divided into a normal articular disc position group and an ADD with and without reduction group. Images reconstructed were used to determine multiple group comparisons of these three different types of disc position, and the diagnostic efficacy for the morphological parameters with significant group difference was analyzed to assess. RESULTS: The condylar volume (CV), condylar superficial area (CSA), superior joint space (SJS), and medial joint space (MJS) all exhibited obvious changes (P < 0.05). Additionally, they all had a reliable diagnostic accuracy in differentiating between normal disc position and ADD with an AUC value from 0.723 to 0.858. Among them, the CV, SJS, and MJS (P < 0.05) had a significantly positive impact on the groups by analysis of multivariate logistic ordinal regression model. CONCLUSIONS: The CV, CSA, SJS, and MJS are significantly associated with different disc displacement types. The condyle in ADD exhibited altered dimensions. These could be promising biometric markers for assessing ADD. CLINICAL RELEVANCE: The morphological changes of mandibular condyle and glenoid fossa were significantly influenced by the status of disc displacement, and condyles with disc displacement had three-dimensionally altered condylar dimensions, irrespective of age and sex.

Investigation of Morphologic Changes in Temporomandibular Joint With Anterior Disk Displacement Based on 3-Dimensional Reconstructive Imaging.

The objective of this study was to measure the association between the disk position and condylar alteration in patients diagnosed with anterior disk displacement (ADD) of temporomandibular joint (TMJ). A retrospective cross-sectional study was designed, dividing into 4 groups: normal articular disk position (NADP) of unilateral ADD patients (n=10), ADD with reduction (ADDwR, n=16), ADD without reduction (ADDwoR, n=24), and healthy volunteers (HV, n=30) based on magnetic resonance imaging and cone-beam computed tomography. After morphologic parameters were calculated from 3-dimensional reconstructive images, differences in parameters with respect to ADD status were tested with analysis of variance and Fisher least significant difference multiple comparisons were performed. Condylar volume of ADDwR, ADDwoR, NADP, and HVs were 1768.29±404.19, 1467.13±438.20, 1814.48±753.60, and 1914.66±476.48 mm, respectively, showing a significant downward trend from healthy disk to a displaced one ( P <0.05). Same trend also found in condylar superficial area, with the condylar superficial area of the ADDwR, ADDwoR, NADP, and HVs were 842.56±138.78 mm, 748.52±157.42 mm, 842.87±263.00 mm, and 892.73±164.19 mm, respectively. From NADP to ADDwR to ADDwoR, superior joint space (SJS) was declined, [SJS (NADP) (2.10±0.91 mm) > SJS (ADDwR) (1.85±0.61 mm) > SJS (ADDwoR) (1.50±0.50 mm), P =0.034]; medial joint space was significantly associated with the different disk displacement types ( P(HV-ADDwR) =0.001; P(HV-ADDwoR) =0.021; P(NADP-ADDwR) =0.022; P(ADDwR-ADDwoR) =0.001). Our findings suggest that condylar volume and superficial area, and superior and medial joint space, albeit with a small sample size, are significantly associated with different disk displacement types, detection of which might therefore be worth exploring for assessing ADD.

Enhancing bacterial cellulose production with hypoxia-inducible factors.

Komagataeibacter xylinus is an aerobic strain that produces bacterial cellulose (BC). Oxygen levels play a critical role in regulating BC synthesis in K. xylinus, and an increase in oxygen tension generally means a decrease in BC production. Fumarate nitrate reduction protein (FNR) and aerobic respiration control protein A (ArcA) are hypoxia-inducible factors, which can signal whether oxygen is present in the environment. In this study, FNR and ArcA were used to enhance the efficiency of oxygen signaling in K. xylinus, and globally regulate the transcription of the genome to cope with hypoxic conditions, with the goal of improving growth and BC production. FNR and ArcA were individually overexpressed in K. xylinus, and the engineered strains were cultivated under different oxygen tensions to explore how their overexpression affects cellular metabolism and regulation. Although FNR overexpression did not improve BC production, ArcA overexpression increased BC production by 24.0% and 37.5% as compared to the control under oxygen tensions of 15% and 40%, respectively. Transcriptome analysis showed that FNR and ArcA overexpression changed the way K. xylinus coped with oxygen tension changes, and that both FNR and ArcA overexpression enhanced the BC synthesis pathway. The results of this study provide a new perspective on the effect of oxygen signaling on growth and BC production in K. xylinus and suggest a promising strategy for enhancing BC production through metabolic engineering. KEY POINTS: • K. xylinus BC production increased after overexpression of ArcA • The young's modulus is enhanced by the ArcA overexpression • ArcA and FNR overexpression changed how cells coped with changes in oxygen tension.

Porphyromonas gingivalis Activation of Tumor-Associated Macrophages via DOK3 Promotes Recurrence of Oral Squamous Cell Carcinoma.

BACKGROUND Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, characterized by high recurrence rate resulting in poor prognosis. Porphyromonas gingivalis, most closely correlated with chronic periodontitis, is increasingly thought to play a significant role in OSCC development via influencing tumor-associated macrophages. However, its specific function remains unclear. In this study, we attempted to explore the mechanism of action of P. gingivalis in the recurrence of OSCC by bioinformatics analysis, to lay a foundation for subsequent basic experiments. MATERIAL AND METHODS The P. gingivalis-infected macrophage microarray dataset (GSE24897) and the OSCC advanced relapse patient microarray dataset (GSE87593) were retrieved from the Gene Expression Omnibus (GEO) database. Differentially-expressed genes (DEGs) were screened using R system, and the intersected DEGs were analyzed for functional enrichment, and protein-protein interaction (PPI) networks were constructed. The expression of significant DEG in GSE24897 microarray was assessed to determine its effect on macrophage immune infiltration in pan-cancer by applying the TIMER 2.0 repository. To detect the expression of DOK3 in OSCC specimens, immunohistochemical (ICH) assay was used. RESULTS A total of 106 co-expressed DEGs were upregulated and 131 were downregulation. The biological processes were mainly enriched in DNA-templated transcription terms, the cellular component enrichment was mainly enriched in the nucleus terms, and the molecular function enrichment was mainly enriched in protein-binding function terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that the DEGs were mainly enriched in the MAPK signaling pathway. Overall analysis of the PPI network showed a significant aggregation, with the top 10 hub co-expressed genes (CASP3, FYN, HNRNPA2B1, NR3C1, RELA, REL, POLR2F, RAN, RHOA, and STAT5B). DOK3 is significantly upregulated in P. gingivalis-infected macrophages, which is associated with macrophage infiltration and differentiation. There was more positive DOK3 staining in the group with P. gingivalis infection. CONCLUSIONS P. gingivalis can affect the recurrence of OSCC by increasing the expression of DOK3 in TAMs, which may be involved in activation of signaling pathways such as TNF and MAPK.

Flexible and stretchable polymer optical fibers for chronic brain and vagus nerve optogenetic stimulations in free-behaving animals.

BACKGROUND: Although electrical stimulation of the peripheral and central nervous systems has attracted much attention owing to its potential therapeutic effects on neuropsychiatric diseases, its non-cell-type-specific activation characteristics may hinder its wide clinical application. Unlike electrical methodologies, optogenetics has more recently been applied as a cell-specific approach for precise modulation of neural functions in vivo, for instance on the vagus nerve. The commonly used implantable optical waveguides are silica optical fibers, which for brain optogenetic stimulation (BOS) are usually fixed on the skull bone. However, due to the huge mismatch of mechanical properties between the stiff optical implants and deformable vagal tissues, vagus nerve optogenetic stimulation (VNOS) in free-behaving animals continues to be a great challenge. RESULTS: To resolve this issue, we developed a simplified method for the fabrication of flexible and stretchable polymer optical fibers (POFs), which show significantly improved characteristics for in vivo optogenetic applications, specifically a low Young's modulus, high stretchability, improved biocompatibility, and long-term stability. We implanted the POFs into the primary motor cortex of C57 mice after the expression of CaMKIIα-ChR2-mCherry detected frequency-dependent neuronal activity and the behavioral changes during light delivery. The viability of POFs as implantable waveguides for VNOS was verified by the increased firing rate of the fast-spiking GABAergic interneurons recorded in the left vagus nerve of VGAT-ChR2 transgenic mice. Furthermore, VNOS was carried out in free-moving rodents via chronically implanted POFs, and an inhibitory influence on the cardiac system and an anxiolytic effect on behaviors was shown. CONCLUSION: Our results demonstrate the feasibility and advantages of the use of POFs in chronic optogenetic modulations in both of the central and peripheral nervous systems, providing new information for the development of novel therapeutic strategies for the treatment of neuropsychiatric disorders.

Morphologic Analysis of Condyle among Different Disc Status in the Temporomandibular Joints by Three-dimensional Reconstructive Imaging: A Preliminary Study.

OBJECTIVES: Morphological study is a common approach in the field of anterior disc displacement (ADD) pathology; however, analysis based on three-dimensional reconstructive imaging has not been investigated. This study investigated the association between ADD and the status of the mandibular condyle and articular fossa. METHODS: Thirty-four patients were divided into three groups: normal articular disc position (NADP), anterior disc displacement with reduction (ADDwR), and anterior disc displacement without reduction (ADDwoR). Multiple grouped comparisons of three different disc statuses were performed by Kruskal-Wallis H test and variance analysis respectively. Receiver-operating characteristic curve was plotted to assess the diagnostic efficacy of the morphological parameters. Multivariate logistic regression analysis was used to investigate the interfering factors of ADD. RESULTS: The condylar volume (CV) and condylar superficial area (CSA) in the NADP, ADDwR, and ADDwoR groups exhibited obvious changes (P < 0.05). Both CV and superior joint space (SJS) presented a good diagnostic accuracy for NADP-ADDwoR [area under the curve (AUC)CV = 0.813; AUCSJS = 0.855)], and ADDwR-ADDwoR (AUCCV = 0.858; AUCSJS = 0.801). CSA presented a good diagnostic accuracy for ADDwR-ADDwoR (AUC = 0.813). A multivariate logistic ordinal regression model showed that the CV [odds ratio (OR) = 1.011; regression coefficient (RC) = 0.011, P = 0.018], SJS (OR, 8.817; RC = 2.177; P < 0.001), and medial joint space (MJS) (OR, 1.492; RC = 0.400; P = 0.047) had a significantly impact on the groups. CONCLUSION: CV, CSA, SJS, and MJS were significantly associated with the different disc status, and the condyle in ADD exhibited 3-dimensionally altered dimensions. They could be considered as promising biometric markers to assess the ADD.

The production of bacterial cellulose in Gluconacetobacter xylinus regulated by luxR overexpression of quorum sensing system.

Quorum sensing is a mechanism that facilitates cell-to-cell communication. Through signal molecular density for signal recognition, which leads to the regulation of some physiological and biochemical functions. Gluconacetobacter xylinus CGMCC 2955, which produces bacterial cellulose (BC), synthesizes the LuxR protein belonging to the LuxI/LuxR type QS system. Here, a luxR overexpression vector was transformed into G. xylinus CGMCC 2955. The overexpression of luxR increased the yield of BC by 15.6% after 16 days static culture and reduced the cell density by 15.5% after 120-h-agitated culture. The glucose was used up by G. xylinus-pMV24-luxR at 72-h-agitated fermentation, which 12 h earlier than the wild-type (WT). The total N-acylhomoserine lactones (AHL) content of the luxR-overexpressing strain and the WT strain attained 1367.9 ± 57.86 mg/L and 842.9 ± 54.22 mg/L, respectively. The C12-HSL and C14-HSL contents of G. xylinus-pMV24-luxR were 202 ± 21.66 mg/L and 409.6 ± 0.91 mg/L, which were significantly lower than that of WT. In contrast, C6-HSL showed opposite results. The difference of AHL content proved that overexpression of luxR improved the binding of AHL and showed preference for some specific AHL. The metabolic results demonstrated that upon glucose exhaustion, the consumption of gluconic acid was promoted by luxR overexpression, and the content of D- ( +)-trehalose, an antiretrograde metabolite, increased significantly. KEY POINTS: • The overexpression of luxR increased the yield of bacterial cellulose • The content of signal molecules was significantly different • Differential metabolites were involved in multiple metabolic pathways.

Tailoring bacterial cellulose structure through CRISPR interference-mediated downregulation of galU in Komagataeibacter xylinus CGMCC 2955.

Diverse applications of bacterial cellulose (BC) have different requirements in terms of its structural characteristics. culturing Komagataeibacter xylinus CGMCC 2955, BC structure changes with alterations in oxygen tension. Here, the K. xylinus CGMCC 2955 transcriptome was analyzed under different oxygen tensions. Transcriptome and genome analysis indicated that BC structure is related to the rate of BC synthesis and cell growth, and galU is an essential gene that controls the carbon metabolic flux between the BC synthesis pathway and the pentose phosphate (PP) pathway. The CRISPR interference (CRISPRi) system was utilized in K. xylinus CGMCC 2955 to control the expression levels of galU. By overexpressing galU and interfering with different sites of galU sequences using CRISPRi, we obtained strains with varying expression levels of galU (3.20-3014.84%). By testing the characteristics of BC, we found that the porosity of BC (range: 62.99-90.66%) was negative with galU expression levels. However, the crystallinity of BC (range: 56.25-85.99%) was positive with galU expression levels; galU expression levels in engineered strains were lower than those in the control strains. Herein, we propose a new method for regulating the structure of BC to provide a theoretical basis for its application in different fields.

Applications of cellulose and chitin/chitosan derivatives and composites as antibacterial materials: current state and perspectives.

The bacterial infections have always a serious problem to public health. Scientists are developing new antibacterial materials to overcome this problem. Polysaccharides are promising biopolymers due to their diverse biological functions, low toxicity, and high biodegradability. Chitin and chitosan have antibacterial properties due to their cationic nature, while cellulose/bacterial cellulose does not possess any antibacterial activity. Moreover, the insolubility of chitin in common solvents, the poor solubility of chitosan in water, and the low mechanical properties of chitosan have restricted their biomedical applications. In order to solve these problems, chemical modifications such as quaternization, carboxymethylation, cationization, or surface modification of these polymers with different antimicrobial agents, including metal and metal oxide nanoparticles, are carried out to obtain new materials with improved physiochemical and biological properties. This mini review describes the recent progress in such derivatives and composites with potential antibacterial applications.

Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry.

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

Enhanced bacterial cellulose production by Gluconacetobacter xylinus via expression of Vitreoscilla hemoglobin and oxygen tension regulation.

Oxygen plays a key role during bacterial cellulose (BC) biosynthesis by Gluconacetobacter xylinus. In this study, the Vitreoscilla hemoglobin (VHb)-encoding gene vgb, which has been widely applied to improve cell survival during hypoxia, was heterologously expressed in G. xylinus via the pBla-VHb-122 plasmid. G. xylinus and G. xylinus-vgb + were statically cultured under hypoxic (10 and 15% oxygen tension in the gaseous phase), atmospheric (21%), and oxygen-enriched conditions (40 and 80%) to investigate the effect of oxygen on cell growth and BC production. Irrespective of vgb expression, we found that cell density increased with oxygen tension (10-80%) during the exponential growth phase but plateaued to the same value in the stationary phase. In contrast, BC production was found to significantly increase at lower oxygen tensions. In addition, we found that BC production at oxygen tensions of 10 and 15% was 26.5 and 58.6% higher, respectively, in G. xylinus-vgb + than that in G. xylinus. The maximum BC yield and glucose conversion rate, of 4.3 g/L and 184.7 mg/g, respectively, were observed in G. xylinus-vgb + at an oxygen tension of 15%. Finally, BC characterization suggested that hypoxic conditions enhance BC's mass density, Young's modulus, and thermostability, with G. xylinus-vgb + synthesizing softer BC than G. xylinus under hypoxia as a result of a decreased Young's modulus. These results will facilitate the use of static culture for the production of BC.

Protective Effect of Salvia Przewalskii Extract on Puromycin-Induced Podocyte Injury.

BACKGROUND: To determine the effect of Salvia przewalskii extract (SPE) from total phenolic acids on puromycin aminonucleoside (PAN)-induced rat podocyte injury. METHODS: The rats were divided into groups that were treated with either PAN only or PAN followed by tacrolimus or SPE. We evaluated the effects of SPE on podocyte injury 5, 10, 15 and 21 days following treatment. RESULTS: (1) Proteinuria was observed starting on day 5 in all groups. The peak levels of proteinuria differed among the groups with tacrolimus and high-dose SPE, which significantly decreased proteinuria relative to the PAN and low- and medium-dose SPE groups. The proteinuria in each group decreased by day 15 and returned to a normal level by day 21. (2) H&E and PAS staining revealed no abnormality in glomerular morphology. With electron microscopy, we observed foot process effacement in the rats of all groups starting on day 5, but rats in the tacrolimus and high-dose SPE groups exhibited a lower degree. (3) IHC staining of nephrin and podocin revealed unaffected expression and better linear distributions in the high-dose SPE and tacrolimus groups. Western blot analysis confirmed that SPE could improve the expression of proteins. (4) The mRNA levels of nephrin and podocin in the tacrolimus and high-dose SPE groups were significantly higher than that in the others. CONCLUSION: In our study, we first demonstrated the ability of SPE to reduce proteinuria, preserve the morphology and structure of podocytes and retain the levels of slit diaphragm proteins on PAN-induced rat podocytes injury.

Chondromyxoid fibroma of the temporomandibular joint - a rare case.

BACKGROUND: Chondromyxoid fibroma (CMF) is a rare cartilaginous tumor, accounting for < 1% of benign bone tumors. We report a case of temporomandibular joint (TMJ)-CMF, involving the pterygopalatine space and skull base and discuss its epidemiology, clinical characteristics, and management. CASE PRESENTATION: A 56-year-old woman presented with facial asymmetry and progressive mouth opening restriction due to a mass expanding upwardly to the auriculotemporal region. Using digital techniques to determine the lesion's boundary and reconstruct the normal glenoid fossa, the temporalis myofascial flap was transplanted between the titanium mesh and condyle to reconstruct the disc after tumor resection. CONCLUSION: This case highlights the importance of identifying patients with TMJ-CMF.