The metabolic reprogramming of γ-aminobutyrate in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy. The oncometabolites have been studied in OSCC, but the mechanism of metabolic reprogramming remains unclear. To identify the potential metabolic markers to distinguish malignant oral squamous cell carcinoma (OSCC) tissue from adjacent healthy tissue and study the mechanism of metabolic reprogramming in OSCC. We compared the metabolites between cancerous and paracancerous tissues of OSCC patients by 1HNMR analysis. We established OSCC derived cell lines and analyzed their difference of RNA expression by RNA sequencing. We investigated the metabolism of γ-aminobutyrate in OSCC derived cells by real time PCR and western blotting. Our data revealed that much more γ-aminobutyrate was produced in cancerous tissues of OSCC patients. The investigation based on OSCC derived cells showed that the increase of γ-aminobutyrate was promoted by the synthesis of glutamate beyond the mitochondria. In OSCC cancerous tissue derived cells, the glutamate was catalyzed to glutamine by glutamine synthetase (GLUL), and then the generated glutamine was metabolized to glutamate by glutaminase (GLS). Finally, the glutamate produced by glutamate-glutamine-glutamate cycle was converted to γ-aminobutyrate by glutamate decarboxylase 2 (GAD2). Our study is not only benefit for understanding the pathological mechanisms of OSCC, but also has application prospects for the diagnosis of OSCC.

[TAN Bayesian network modeling of online learning decision making of dental undergraduates during the COVID-19 pandemic].

PURPOSE: To perceive the dental undergraduate's policy of coping with online learning and their decision-making laws during the COVID-19 pandemic. METHODS: For dental undergraduate students from the 2016 grade to 2018 grade of Lishui University, two prospective questionnaire surveys were conducted before the online course starting and four weeks later. SPSS Modeler18.0 software was used to screen, review, and analyze the data. TAN (tree augmented naive) Bayesian network models were utilized to analyze and predict variables. Indicators like the overall prediction accuracy, receiver operating characteristic curve (ROC curve), and area under the ROC curve(AUC value) were applied to evaluate the model's predicting performances. RESULTS: The case score of each survey was 422 and 382, and the Cronbach's α coefficients of internal consistency were 0.91 and 0.82. Among the decision-making variables in the aspect of "whether to preview online learning materials", the top-two variables were "looking forward to the semester beginning" and "the validity of the network materials". In speaking of "whether the online courses meet the offline course standards", the top-three variables were "the rhythm of lecturing on live or in recorded videos", "how many online tasks', and" the data frame and organization". The overall prediction accuracy of each constructed TAN Bayesian network model was 89.42% and 87.82%, and their AUC values were 0.75 and 0.93, respectively. CONCLUSIONS: To truly make online courses comparable to the off-line curriculum, teachers should fully understand how the students cope with their online learning at first. Then, only by perceiving and recognizing the students' expectations for education, by efficiently preparing and organizing online materials with all-round, clearly-structured, vivid, comprehensible contents and moderate difficult tasks, by well interacting with students through different websites and social media, can we truly achieve " ongoing learning with suspended class".

Phenytoin sodium-ameliorated gingival fibroblast aging is associated with autophagy.

BACKGROUND AND OBJECTIVE: Human gingival fibrolasts aging is an important cause of periodontal disease. Phenytoin sodium (phenytoin) has a side effect of gingival hyperplasia and an effect on the autophagy progress. This study investigated whether the effect of phenytoin on aging gingival fibroblast is related to the autophagy pathway. MATERIAL AND METHODS: The aging model of gingival fibroblast cell line HGF-1 was induced by hydrogen peroxide (H2 O2 ), and the treatment of phenytoin and 3-methyladenine (3-MA) was performed simultaneously. Cell viability, cell cycle, and intracellular calcium ion were measured by flow cytometry. Changes in expression of basic fibroblast growth factor (bFGF), P16INK4A , P21cip1 , and bFGF, P16INK4A , P21cip1 , LC3II, p62, and Beclin were tested by using reverse transcription polymerase chain reaction, western blot, and immunofluorescence staining. RESULTS: The results showed that aging HGF-1 proliferation was inhibited by H2 O2 , gene, protein expression of bFGF, P16INK4A , and P21cip1 were decreased, autophagy-related proteins LC3II, p62, and Becline were decreased, and the proportion of G0/G1 phase and intracellular calcium ion of cell cycle was increased. Phenytoin treatment could recovery above changes, but the effect of phenytoin could be blocked by 3-MA. CONCLUSION: We propose that phenytoin alleviates the aging of gingival fibroblasts induced by H2 O2 . This condition is related to the enhancement of autophagy pathway.

Topography-dependent antibacterial, osteogenic and anti-aging properties of pure titanium.

After nearly half a century of development under the guidance of the osseointegration theory, the major dilemmas for current implant dentistry are the implant associated infection and insufficient osseointegration. Moreover, biological aging of titanium (Ti) implants also brings great uncertainty to clinical results. In the present study, a novel nano-micro-hierarchical topography pattern is created by sandblasting and dual acid-etching on a Ti surface. The physico-chemical properties of the surfaces were characterized by scanning electron microscopy, contact angle measurement, X-ray photoelectron spectroscopy and X-ray diffraction. The effects of the hierarchical surfaces on osteoprogenitor cell growth and bacterial activities were separately evaluated. The optimized nano-micro-hierarchical Ti surface exhibits surprisingly topography-dependent antibacterial capacity via inhibiting bacterial adhesion of several species in the early stage and better osteogenesis ability than the microscaled surface. Aging studies demonstrate that, compared with the surface with a microscale structure, the nano-micro-hierarchical Ti surface has greater anti-aging ability manifested as being more capable to retain hydrophilicity and bioactivity during aging. Furthermore, the present study reveals that the biological aging of the Ti implant is attributed to two decisive factors during the aging period: the progressively thickened amorphous TiO2 layer by autoxidation and the unavoidable accumulation of hydrocarbons on the Ti implant surface.

Reduction-triggered release of paclitaxel from in situ formed biodegradable core-cross-linked micelles.

Paclitaxel-loaded reduction-responsive core-crosslinked micelles were prepared in situ in aqueous media via"click" chemistry. An amphiphilic block copolymer with multiple pendant azide groups was first synthesized through the controlled ring-opening copolymerization of ε-caprolactone (CL) and 5,5-dibromomethyl trimethylene carbonate (DBTC) in the presence of methoxy poly(ethylene glycol) (mPEG) as a macroinitiator, followed by azidation. This amphiphilic block copolymer could self-assemble into micelles and paclitaxel (PTX) could be encapsulated into the micellar core to form PTX-loaded micelles, which were core-crosslinked in situ by propargyl dithiopropionate via"click" chemistry, to develop a reduction-responsive polymeric drug delivery system. The in vitro release studies revealed the minimized release of PTX under physiological conditions, whereas a burst release of PTX was observed in response to reductive conditions. The core-crosslinked micelles displayed efficient cell-uptake and reduction-responsive drug release due to the nanoscale diameter and splitting of disulfide bonds under a reductive environment, which was confirmed by confocal laser scanning microscopy using Nile red as a fluorescent probe. This kind of polymeric nano-carrier with excellent biocompatibility and quick reduction-response opens a new avenue to intracellular anticancer drug delivery.

The construction of hierarchical structure on Ti substrate with superior osteogenic activity and intrinsic antibacterial capability.

The deficient osseointegration and implant-associated infections are pivotal issues for the long-term clinical success of endosteal Ti implants, while development of functional surfaces that can simultaneously overcome these problems remains highly challenging. This study aimed to fabricate sophisticated Ti implant surface with both osteogenic inducing activity and inherent antibacterial ability simply via tailoring surface topographical features. Micro/submciro/nano-scale structure was constructed on Ti by three cumulative subtractive methods, including sequentially conducted sandblasting as well as primary and secondary acid etching treatment. Topographical features of this hierarchical structure can be well tuned by the time of the secondary acid treatment. Ti substrate with mere micro/submicro-scale structure (MS0-Ti) served as a control to examine the influence of hierarchical structures on surface properties and biological activities. Surface analysis indicated that all hierarchically structured surfaces possessed exactly the same surface chemistry as that of MS0-Ti, and all of them showed super-amphiphilicity, high surface free energy, and high protein adsorption capability. Biological evaluations revealed surprisingly antibacterial ability and excellent osteogenic activity for samples with optimized hierarchical structure (MS30-Ti) when compared with MS0-Ti. Consequently, for the first time, a hierarchically structured Ti surface with topography-induced inherent antibacterial capability and excellent osteogenic activity was constructed.

Acid-triggered drug release from micelles based on amphiphilic oligo(ethylene glycol)-doxorubicin alternative copolymers.

We report a facile strategy to synthesize pH-sensitive amphiphilic oligo(ethylene glycol) (OEG)-doxorubicin (DOX) alternative conjugates. Poly[oligo(ethylene glycol) malicate] (POEGM) with numerous pendent hydroxyl groups was first synthesized by the direct polycondensation of oligo(ethylene glycol) (OEG) with malic acid under mild conditions. Then, benzaldehyde groups were introduced into the POEGM backbone via esterification between the pendant hydroxyl groups and 4-formylbenzoic acid. DOX moieties were finally attached to the polymeric backbone via benzoic imine linkages to obtain the OEG-DOX conjugates. Because of the high molecular weight and alternate architecture, this type of amphiphilic OEG-DOX alternative conjugates can form stable micelles in aqueous solution with a high DOX loading content (38.2 wt%) and low critical micelle concentrations (0.021 mg mL-1). Due to the pH-sensitive benzoic imine linkages between the DOX moieties and polymeric backbone, DOX could be rapidly released from the micelles at pH 5.8, whereas only a minimal amount of DOX was released at pH 7.4 under the same conditions. The cytotoxicity assay indicates that the OEG-DOX conjugates show cytotoxic effects to MCF-7 tumor cells, while the corresponding polymer material POEGM-CHO exhibits a great biocompatibility for MCF-7 tumor cells. These pH-sensitive and high drug loading nano-carriers based on the OEG-DOX alternative conjugates provide a promising platform for targeted cancer therapy.

A facile strategy to prepare redox-responsive amphiphilic PEGylated prodrug with high drug loading content and low critical micelle concentration.

A redox-responsive amphiphilic polymeric prodrug was synthesized in a facile way by polycondensation of oligo(ethylene glycol) with dicarboxylic acids including malic acid and 3,3'-dithiodipropionic acid , followed by esterification with ibuprofen, which was used as a model drug. Because of its amphiphilic nature and relatively high molecular weight, this polymeric prodrug can form stable micelles in aqueous media with a low critical micellar concentration (CMC). Free ibuprofen molecules can be steadily incorporated into the core of these micelles with a surprisingly high loading content (38.9 wt%), owing to hydrophobic interaction and π-π stacking with the ibuprofen moieties in the copolymer. The in vitro release results indicate that there was a relatively slow and sustained release of the conjugated ibuprofen moieties, while encapsulated ibuprofen molecules showed a rapid release. Furthermore, for both the conjugated ibuprofen and the encapsulated ibuprofen there was an accelerated release in the presence of 10 mM dl-dithiothreitol due to cleavage of the disulfide bonds, which lead to disassociation of the micelles. Notably, this prodrug was revealed to have excellent cell compatibilities via a cell counting kit-8 (CCK-8) assay. Confocal laser scanning microscope observations indicated that the micelles based on the polymeric prodrug can be taken up quickly by cells and present a redox-responsive drug release in cytoplasm. This kind of polymeric nanocarrier with a high drug loading content, low CMC, excellent biocompatibility and rapid response to a reductive environment may have tremendous scope in the area of controlled drug delivery.

Biomimetic ECM coatings for controlled release of rhBMP-2: construction and biological evaluation.

As we all know biochemical surface modification is promising for implantable biomedical device applications due to its ability to directly provide therapeutic molecular cues for tissue repair. However, presenting multiple molecular cues on implant surfaces in the proper way is challenging. In this study, a multi-component polyelectrolyte multilayer (PEM) coating composed of collagen type I, RGD peptide functionalized hyaluronic acid, and recombined human BMP-2 (rhBMP-2) was constructed on Ti via a layer by layer technique. Subsequently, this coating was crosslinked via disulfide bonds to form a surface gel coating with a semi-interpenetrating network. A disulfide-crosslinked RGD-containing biomimetic extracellular matrix coating that could serve as a reservoir for rhBMP-2 was thus obtained. The embedded rhBMP-2 displayed a sustained release profile and a strong resistance to the physiological environment. In vitro biological evaluation revealed that the resultant disulfide crosslinking bioactive coating could effectively modulate cellular behaviors of pre-osteoblasts such as adhesion, proliferation and differentiation. In vivo study further revealed that this coating could enhance the bone-to-implant integration characterized by the increased removal torque values.

[A survey of first molar caries among primary school students in Lishui].

PURPOSE: To elucidate school age students' oral health status in Lishui city and monitor caries tendency of their first molars. METHODS: Four hundred and forty-eight primary school students of the first and second grades were cluster sampled from the urban and suburb districts. The first molar crown caries were measured and their oral health caring measures were investigated. RESULTS: The results showed that suburb children's DMFT and first molar caries prevalence were both higher than the children in the urban district, but the time of tooth brushing was obviously lower. The results also showed the most important influencing factors of caries were tooth brushing, followed by age, districts, and gender etc. CONCLUSION: It is suggested that we should enforce the oral health care education and promotion, especially in the suburb area.