Tumor-repopulating cells evade ferroptosis via PCK2-dependent phospholipid remodeling.

Whether stem-cell-like cancer cells avert ferroptosis to mediate therapy resistance remains unclear. In this study, using a soft fibrin gel culture system, we found that tumor-repopulating cells (TRCs) with stem-cell-like cancer cell characteristics resist chemotherapy and radiotherapy by decreasing ferroptosis sensitivity. Mechanistically, through quantitative mass spectrometry and lipidomic analysis, we determined that mitochondria metabolic kinase PCK2 phosphorylates and activates ACSL4 to drive ferroptosis-associated phospholipid remodeling. TRCs downregulate the PCK2 expression to confer themselves on a structural ferroptosis-resistant state. Notably, in addition to confirming the role of PCK2-pACSL4(T679) in multiple preclinical models, we discovered that higher PCK2 and pACSL4(T679) levels are correlated with better response to chemotherapy and radiotherapy as well as lower distant metastasis in nasopharyngeal carcinoma cohorts.

MYRF: A unique transmembrane transcription factor- from proteolytic self-processing to its multifaceted roles in animal development.

The Myelin Regulator Factor (MYRF) is a master regulator governing myelin formation and maintenance in the central nervous system. The conservation of MYRF across metazoans and its broad tissue expression suggest it has functions extending beyond the well-established role in myelination. Loss of MYRF results in developmental lethality in both invertebrates and vertebrates, and MYRF haploinsufficiency in humans causes MYRF-related Cardiac Urogenital Syndrome, underscoring its importance in animal development; however, these mechanisms are largely unexplored. MYRF, an unconventional transcription factor, begins embedded in the membrane and undergoes intramolecular chaperone mediated trimerization, which triggers self-cleavage, allowing its N-terminal segment with an Ig-fold DNA-binding domain to enter the nucleus for transcriptional regulation. Recent research suggests developmental regulation of cleavage, yet the mechanisms remain enigmatic. While some parts of MYRF's structure have been elucidated, others remain obscure, leaving questions about how these motifs are linked to its intricate processing and function.

A fast microbial nitrogen-assimilation technology enhances nitrogen migration and single-cell-protein production in high-ammonia piggery wastewater.

Conventional methods, such as freshwater dilution and ammonia stripping, have been widely employed for microalgae-based piggery wastewater (PW) treatment, but they cause high freshwater consumption and intensive ammonia loss, respectively. This present work developed a novel fast microbial nitrogen-assimilation technology by integrating nitrogen starvation, zeolite-based adsorption, pH control, and co-culture of microalgae-yeast for the PW treatment. Among them, the nitrogen starvation accelerated the nitrogen removal and shortened the treatment period, but it could not improve the tolerance level of microalgal cells to ammonia toxicity based on oxidative stress. Therefore, zeolite was added to reduce the initial total ammonia-nitrogen concentration to around 300 mg/L by ammonia adsorption. Slowly releasing ammonia at the later phase maintained the total ammonia-nitrogen concentration in the PW. However, the pH increase could cause lots of ammonia loss air and pollution and inhibit the desorption of ammonia from zeolite and the growth and metabolism of microalgae during the microalgae cultivation. Thus, the highest biomass yield (3.25 g/L) and nitrogen recovery ratio (40.31%) were achieved when the pH of PW was controlled at 6.0. After combining the co-cultivation of microalgae-yeast, the carbon-nitrogen co-assimilation and the alleviation of pH fluctuation further enhanced the nutrient removal and nitrogen migration to high-protein biomass. Consequently, the fast microbial nitrogen-assimilation technology can help update the industrial system for high-ammonia wastewater treatment by improving the treatment and nitrogen recovery rates.

Mechanisms of low cadmium accumulation in crops: A comprehensive overview from rhizosphere soil to edible parts.

Cadmium (Cd) is a toxic heavy metal often found in soil and agricultural products. Due to its high mobility, Cd poses a significant health risk when absorbed by crops, a crucial component of the human diet. This absorption primarily occurs through roots and leaves, leading to Cd accumulation in edible parts of the plant. Our research aimed to understand the mechanisms behind the reduced Cd accumulation in certain crop cultivars through an extensive review of the literature. Crops employ various strategies to limit Cd influx from the soil, including rhizosphere microbial fixation and altering root cell metabolism. Additional mechanisms include membrane efflux, specific transport, chelation, and detoxification, facilitated by metalloproteins such as the natural resistance-associated macrophage protein (Nramp) family, heavy metal P-type ATPases (HMA), zinc-iron permease (ZIP), and ATP-binding cassette (ABC) transporters. This paper synthesizes differences in Cd accumulation among plant varieties, presents methods for identifying cultivars with low Cd accumulation, and explores the unique molecular biology of Cd accumulation. Overall, this review provides a comprehensive resource for managing agricultural lands with lower contamination levels and supports the development of crops engineered to accumulate minimal amounts of Cd.

Degradation of triclosan by peroxydisulfate/peroxomonosulfate binary oxidants activation under thermal conditions: Efficiency and mechanism.

Peroxydisulfate (PDS) and peroxymonosulfate (PMS) could be efficiently activated by heat to generate reactive oxygen species (ROS) for the degradation of organic contaminants. However, defects including the inefficiency treatment and pH dependence of monooxidant process are prominent. In this study, synergy of heat and the PDS-PMS binary oxidant was studied for efficient triclosan (TCS) degradation and apply in rubber wastewater. Under different pH values, the degradation of TCS followed pseudo-first-order kinetics, the reaction rate constant (kobs) value of TCS in heat/PDS/PMS system increased from 1.8 to 4.4 fold and 6.8-49.1 fold when compared to heat/PDS system and heat/PMS system, respectively. Hydroxyl radicals (·OH), sulfate radicals (SO4·-) and singlet oxygen (1O2) were the major ROS for the degradation of TCS in heat/PDS/PMS system. In addition, the steady-state concentrations of ·OH/1O2 and SO4·-/·OH/1O2 increased under acidic conditions and alkaline conditions, respectively. It was concluded that the pH regulated the ROS for degradation of TCS in heat/PDS/PMS system significantly. Based on the analysis of degradation byproducts, it was inferred that the dechlorination, hydroxylation and ether bond breaking reactions occurred during the degradation of TCS. Moreover, the biological toxicity of the ten byproducts was lower than that of TCS was determined. Furthermore, the heat/PDS/PMS system is resistant to the influence of water substrates and can effectively improve the water quality of rubber wastewater. This study provides a novel perspective for efficient degradation of TCS independent of pH in the heat/PDS/PMS system and its application of rubber wastewater.

Role of acyl-coenzyme A: cholesterol transferase 1 (ACAT1) in retinal neovascularization.

BACKGROUND: We have investigated the efficacy of a new strategy to limit pathological retinal neovascularization (RNV) during ischemic retinopathy by targeting the cholesterol metabolizing enzyme acyl-coenzyme A: cholesterol transferase 1 (ACAT1). Dyslipidemia and cholesterol accumulation have been strongly implicated in promoting subretinal NV. However, little is known about the role of cholesterol metabolism in RNV. Here, we tested the effects of inhibiting ACAT1 on pathological RNV in the mouse model of oxygen-induced retinopathy (OIR). METHODS: In vivo studies used knockout mice that lack the receptor for LDL cholesterol (LDLR-/-) and wild-type mice. The wild-type mice were treated with a specific inhibitor of ACAT1, K604 (10 mg/kg, i.p) or vehicle (PBS) during OIR. In vitro studies used human microglia exposed to oxygen-glucose deprivation (OGD) and treated with the ACAT1 inhibitor (1 µM) or PBS. RESULTS: Analysis of OIR retinas showed that increased expression of inflammatory mediators and pathological RNV were associated with significant increases in expression of the LDLR, increased accumulation of neutral lipids, and formation of toxic levels of cholesterol ester (CE). Deletion of the LDLR completely blocked OIR-induced RNV and significantly reduced the AVA. The OIR-induced increase in CE formation was accompanied by significant increases in expression of ACAT1, VEGF and inflammatory factors (TREM1 and MCSF) (p < 0.05). ACAT1 was co-localized with TREM1, MCSF, and macrophage/microglia makers (F4/80 and Iba1) in areas of RNV. Treatment with K604 prevented retinal accumulation of neutral lipids and CE formation, inhibited RNV, and decreased the AVA as compared to controls (p < 0.05). The treatment also blocked upregulation of LDLR, ACAT1, TREM1, MCSF, and inflammatory cytokines but did not alter VEGF expression. K604 treatment of microglia cells also blocked the effects of OGD in increasing expression of ACAT1, TREM1, and MCSF without altering VEGF expression. CONCLUSIONS: OIR-induced RNV is closely associated with increases in lipid accumulation and CE formation along with increased expression of LDLR, ACAT1, TREM1, and MCSF. Inhibiting ACAT1 blocked these effects and limited RNV independently of alterations in VEGF expression. This pathway offers a novel strategy to limit vascular injury during ischemic retinopathy.

Male antiphonal calls and phonotaxis evoked by female courtship calls in the large odorous frog (Odorrana graminea).

Acoustic communication plays a vital role in frog reproduction. In most anuran species, long-distance sound communication is one-way from males to females; during the reproductive season, males produce species-specific advertisement calls to attract gravid females, and females are generally silent but perform phonotactic movements that lead to amplexus. One exception is the concave-eared torrent frog (Odorrana tormota). In this species, females produce courtship calls that elicit antiphonal vocalizations by males, followed by precise phonotactic movements. The large odorous frog O. graminea (previously Odorrana livida) in southern China is subject to the same environmental constraints as O. tormota, with which it is sympatric; it is unclear whether their sound communication is one-way or bidirectional. Here, we provide the first data on female O. graminea vocalizations and their functions. Using playbacks of female calls, we conducted acoustic behavioral experiments in the laboratory in response to which males emitted single- or multi-note antiphonal calls with a varying fundamental frequency. Moreover, they were attracted to female call playbacks, exhibiting precise phonotaxis. The female courtship call-male response interaction thus forms a duet between partners of a receptive pair. These results demonstrate that this unique communication system likely reflects an adaptation to an environment in which short-distance communication is at a premium given the high levels of ambient noise.

Hydrogen Peroxide/Phosphoric Acid Modification of Hydrochars for Sulfamethoxazole and Carbamazepine Adsorption: The Role of Oxygen-Containing Functional Groups.

Emerging pollutants, such as sulfonamide antibiotics and pharmaceuticals, have been widely detected in water and soils, posing serious environmental and human health concerns. Thus, it is urgent and necessary to develop a technology for removing them. In this work, a hydrothermal carbonization method was used to prepare the hydrochars (HCs) by pine sawdust with different temperatures. To improve the physicochemical properties of HCs, phosphoric acid (H3PO4) and hydrogen peroxide (H2O2) were used to modify these HCs, and they were referred to as PHCs and HHCs, respectively. The adsorption of sulfamethoxazole (SMX) and carbamazepine (CBZ) by pristine and modified HCs was investigated systematically. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicated that the H2O2/H3PO4 modification led to the formation of a disordered carbon structure and abundant pores. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy results suggested that carboxyl (-COOH) and hydroxyl (-OH) functional groups of HCs increased after modification, which is the main reason for the higher sorption of SMX and CBZ on H3PO4/H2O2-modified HCs when compared with pristine HCs. In addition, the positive correlation between -COOH/C=O and logKd of these two chemicals also suggested that oxygen-containing functional groups played a crucial role in the sorption of SMX and CBZ. The strong hydrophobic interaction and π-π interaction between CBZ and pristine/modified HCs resulted in its higher adsorption when compared with SMX. The results of this study provide a novel perspective on the investigation of adsorption mechanisms and environmental behaviors for organic contaminants by pristine and modified HCs.

Application of dental pulp stem cells in oral maxillofacial tissue engineering.

In the maxillofacial area, soft and hard tissue abnormalities are caused by trauma, tumors, infection, and other causes that expose the maxillofacial region to the surface of the human body. Patients' normal physiological function and appearance are interfered with, and their mental health is adversely impacted, reducing their overall life quality. The pursuit of appropriate medical treatments to correct these abnormalities is thus vital. Autologous stem cell regeneration technology mainly focused on tissues has lately emerged as a significant problem in the medical community. Because of the capacity of dental pulp stem cells (DPSCs) to self-renew, the use of DPSCs from the human pulp tissues of deciduous teeth or permanent teeth has gained popularity among scientists as a stem cell-based therapy option. Aside from that, they are simple to extract and have minimal immunogenicity. As a result, bone tissue engineering may be a critical component in treating maxillofacial and periodontal bone abnormalities. DPSCs activity in maxillofacial and periodontal tissue-engineered bone tissue was investigated in this research.

Analysis of Blueberry Plant Rhizosphere Bacterial Diversity and Selection of Plant Growth Promoting Rhizobacteria.

Microbial metabolites in rhizosphere soil are important to plant growth. In this study, microbial diversity in blueberry plant rhizosphere soil was characterized using high-throughput amplicon sequencing technology. There were 11 bacterial phyla and three fungal phyla dominating in the soil. In addition, inorganic-phosphate-solubilizing bacteria (iPSB) in the rhizosphere soil were isolated and evaluated by molybdenum-antimony anti-coloration method. Their silicate solubilizing, auxin production, and nitrogen fixation capabilities were also determined. Eighteen iPSB in the rhizosphere soil strains were isolated and identified as Buttiauxella, Paraburkholderia and Pseudomonas. The higher phosphorus-solubilizing capacity and auxin production in blueberry rhizosphere belonged to genus Buttiauxella sp. The strains belong to genus Paraburkholderia had the same function of dissolving both phosphorus and producing auxin, as well as silicate and nitrogen fixation. The blueberry seeds incubated with the strains had higher germination rates. The results of this study could be helpful in developing the plant growth-promoting rhizobacteria (PGPR) method for enhancing soil nutrients to blueberry plant.

Epithelial-Mesenchymal Transition-Mediated Tumor Therapeutic Resistance.

Cancer is one of the world's most burdensome diseases, with increasing prevalence and a high mortality rate threat. Tumor recurrence and metastasis due to treatment resistance are two of the primary reasons that cancers have been so difficult to treat. The epithelial-mesenchymal transition (EMT) is essential for tumor drug resistance. EMT causes tumor cells to produce mesenchymal stem cells and quickly adapt to various injuries, showing a treatment-resistant phenotype. In addition, multiple signaling pathways and regulatory mechanisms are involved in the EMT, resulting in resistance to treatment and hard eradication of the tumors. The purpose of this study is to review the link between EMT, therapeutic resistance, and the molecular process, and to offer a theoretical framework for EMT-based tumor-sensitization therapy.

Engineered 3D-Printed Polyvinyl Alcohol Scaffolds Incorporating ß-Tricalcium Phosphate and Icariin Induce Bone Regeneration in Rat Skull Defect Model.

The skull defects are challenging to self-heal, and autologous bone graft repair has numerous drawbacks. The scaffolds for the rapid and effective repair of skull defects have become an important research topic. In this study, polyvinyl alcohol (PVA)/ß-tricalcium phosphate(ß-TCP) composite scaffolds containing icariin (ICA) were prepared through direct-ink three-dimensional (3D) printing technology. ß-TCP in the composite scaffold had osteoconductive capability, and the ICA molecule had osteoinductive capacity. The ß-TCP and ICA components in the composite scaffold can enhance the capability to repair skull defects. We show that ICA exhibited a slow-release behaviour within 80 days. This behaviour helped the scaffold to continuously stimulate the formation of new bone. The results of in vitro cell compatibility experiments showed that the addition of ICA molecules contributed to the adhesion and proliferation of MC-3T3-E1 cells. The level of alkaline phosphatase secretion demonstrated that the slow release of ICA can promote the osteogenic differentiation of MC-3T3-E1 cells. The introduction of ICA molecules accelerated the in situ bone regeneration in in vivo. It is concluded that the 3D-printed PVA scaffold with ß-TCP and ICA has a wide range of potential applications in the field of skull defect treatment.

Carboxypeptidase Y Assisted Disulfide-Bond Identification with Linearized Database Search.

A disulfide bond is an important protein post-translational modification and plays a key role in regulating protein oxidation status, protein structure, and stability. Analysis of a disulfide bond using mass spectrometry is challenging because there lacks an efficient method to separate the disulfide-linked peptides from a complex protein digest, and the MS data requires sophisticated interpretation. Here, we developed a novel disulfide bond identification strategy, termed as "carboxypeptidase Y assisted disulfide-bond identification (CADI)". CADI is able to significantly reduce sample complexity by depleting ∼90% of the linear peptides while keeping the disulfide-bonded peptides. Furthermore, all CADI data can be directly analyzed by widely used protein database search engines, such as Mascot and MaxQuant. Our data show that CADI is able to sensitively identify disulfide bonds in peptides and proteins. However, CADI has not yet achieved a satisfied in-depth coverage on complex mammalian cell lysates due to the limited enzymatic activity of carboxypeptidase Y and low occurrences of disulfide bonds in a proteome. Altogether, CADI is a useful method that can get disulfide-linked peptides enriched and analyzed with regular search engines. CADI holds great potentials to deepen the analysis of disulfide bond and other types of cross-linked peptides on the proteome scale.

A bispecific nanobody targeting the dimerization interface of epidermal growth factor receptor: Evidence for tumor suppressive actions in vitro and in vivo.

Targeting the dimer interface for the epidermal growth factor receptor (EGFR) that is highly conserved in the structure and directly involved in dimerization may solve the resistance problem that plagues anti-EGFR therapy. Heavy chain single domain antibodies have promising prospects as therapeutic antibodies. A bispecific nanobody was constructed based on previously screened humanized nanobodies that target the ß-loop at the EGFR dimer interface, an anti-FcγRIIIa (CD16) of natural killer cells (NK) nanobodies and anti-human serum albumin (HSA) nanobodies. The target gene was effectively expressed and secreted while controlled by promoter GAP in Pichia pastoris X33, and the expressed product was purified with a cation exchange and nickel chelation chromatography. The bispecific nanobody specifically bound to the surfaces of EGFR-overexpressed human epidermal carcinoma A431 cells and effectively inhibited tumor cell growth both in vitro and in vivo. In the A431 cell nude mouse xenograft model, the growth inhibition effect from the bispecific nanobody was significantly increased with the assistance of peripheral blood mononuclear cells (PBMCs), which was consistent with the results obtained in vitro, suggesting that there was an antibody-dependent cell-mediated cytotoxicity (ADCC) effect. In addition, the intraperitoneal administration of bispecific nanobodies effectively reached tumor tissues in the shoulder dorsal region, but in significantly less distributed quantities than EGFR Dimer Nb77. To conclude, a bispecific nanobody targeting the EGFR dimer interface with ADCC effect was successfully constructed.

Expression profile of circular RNA and construction of circular RNA-Micro RNA network in salivary adenoid cystic carcinoma.

BACKGROUND: Circular RNAs (circRNAs) is a newly discovered type of non-coding RNA, the abnormal expression of which has been demonstrated in many types of human tumors. So they have been considered as promising candidates as diagnostic and therapeutic targets in cancer. This research aimed to screen the profile of circRNA expression in salivary adenoid cystic carcinoma (SACC). METHODS: Using the threshold of FDR < 0.05 and fold change > 2 or < 0.5, 5 up-regulated and 26 down-regulated circRNAs were identified. The reliability of sequencing was verified by the expression detection of randomly selected circRNAs via qRT-PCR. RESULTS: Moreover, the circRNA-miRNA system was established by bioinformatics approaches and successfully identified an interaction between circRNA ABCA13 and a cancer-related miRNA (miR-138-5p), which was also verified by qRT-PCR. Moreover, the predicted molecular interaction proved that circRNA ABCA13 may promote SACC through inhibition of miR-138-5p. CONCLUSIONS: Collectively, this study has offered the first report about the circRNA expression profile and circRNA-miRNA network in SACC. All of the above could benefit the exploration of novel therapeutic target in SACC treatment.

Advanced treatment of dye wastewater using a novel integrative Fenton-like/MnO2-filled upward flow biological filter bed system equipped with modified ceramsite.

The deposal of residual hydrogen peroxide (H2O2) in Fenton-like system and the requirement of oxygen in bioreactor are essential parts for the treatment of integrative Fenton-like/bioreactor. A novel low-cost integrative Fenton-like and MnO2-filled upward flow biological filter bed (Fenton-like/MBFB) equipped with the modified ceramsite was constructed to evaluate the main properties and catalytic activity of modified ceramsite, and the optimal conditions of integrative system and compare integrative and traditional systems. In this study, the Fenton-like reactor with modified ceramsite had higher catalytic ability whose Acid Orange 7 (AO7) degradation efficiency reached to 79.3% due to large surface area and high porosity, compared with that with raw ceramsite (44.3%). Furthermore, total utilization efficiency of H2O2 in integrative system (from 32.41% to 53.51%) and removal efficiencies of COD and AO7 were remarkably improved, which would effectively decrease the waste of H2O2 and the setting of regulation pool and aeration tank. Thus, the integrative system can save 0.51 CNY/m3 in construction cost and 0.21 CNY/m3 in operating cost. The average COD removal efficiency, AO7 degradation efficiency and effluent DO concentration were achieved to 64.8%, 79.5% and 9.3 mg/L respectively in integrative system were achieved in integrative system during sixty successive runs. Also, the potential degradation pathway of contaminants was also proposed according to the OH-enhanced at Fenton-like reactor due to catalyst and adsorption of modified ceramsite and the removal of microorganisms and modified ceramsite for contaminants at MBFB. This study demonstrated the feasibility of integrative Fenton-like/MBFB filled with modified ceramsite for simultaneously decreasing operational cost and complexity and enhancing removal efficiency, thus provided a one-step alternative for refractory dye wastewater.

Dispersive liquid-liquid microextraction based on a new hydrophobic deep eutectic solvent for the determination of phenolic compounds in environmental water samples.

Dispersive liquid-liquid microextraction has garnered increasing attention in sample preparation due to its rapid and efficient extraction process. In this study, a new terpineol-based hydrophobic deep eutectic solvent was firstly synthesized by mixing α-terpineol with 1-octanoic acid, and then applied to analysis of phenols from water samples by dispersive liquid-liquid microextraction combined with high-performance liquid chromatography and diode array detection. Infrared spectroscopy indicated that hydrogen bonding was responsible for the formation of deep eutectic solvent between α-terpineol and 1-octanoic acid. After optimization of several parameters, such as the type and volume of deep eutectic solvent and the disperser, pH and ionic strength of sample solution, the developed method exhibited excellent extraction performance to the phenols with the enrichment factors from 27 to 32. Good linearity was acquired ranging from 5 to 5000 µg/L, and detection of limits of the proposed method for the phenols ranged from 0.15 to 0.38 µg/L. The recoveries measured by spiked samples at three concentration levels ranged from 81.6 to 99.3%, and precision was found with intra- and inter-day relative standard deviations less than 8.7 and 9.2%, respectively. Finally, the proposed method was successfully applied to the determination of the phenols in environmental water samples.

Cardiac Rehabilitation Perceptions Among Healthcare Providers in China: A Mixed-Methods Study.

BACKGROUND: Cardiac rehabilitation (CR) in China has not been widely adopted for a variety of reasons, including healthcare provider (HCP)s' lack of awareness and beliefs. OBJECTIVE: To explore HCP's perceptions of CR in China. METHODS: An exploratory, sequential design was used in this mixed-methods study. Face-to-face semi-structured interviews were performed; this was followed by a cross-sectional survey. SETTING: The interviews were conducted in a university-affiliated hospital and a rehabilitation hospital in Shanghai. The survey was conducted in the cardiac departments of primary, secondary, or tertiary hospitals in Shanghai or Yunnan Province, China. PARTICIPANTS: Saturation was achieved upon interviewing 13 HCPs (5 doctors, and 8 nurses). A total of 610 HCPs (185 doctors [30.5%], 417 nurses [68.8%]) completed the survey. RESULTS: Analysis of the interviews revealed 4 themes: the perceived value of CR, the need for pro-CR policy, variability in CR awareness, and obstacles to CR delivery. HCP approaches to the treatment of patients with cardiac conditions did not universally include exercise training (only approximately 60% of HCPs), or all other recommended domains of secondary prevention, and assessment of the major risk factors was quite low. Familiarity with CR was moderate (48.7%). HCPs perceived that philosophies of Traditional Chinese Medicine (TCM) were highly compatible with, and could add value to, CR. HCP approaches to secondary preventive care and CR perceptions varied significantly according to their highest level of education, clinical profession, job seniority, type of hospital where they worked, whether the hospital had a CR program and the hospital's location. CONCLUSION: HCPs recognize the value of CR, particularly considering secondary preventive care practices were not comprehensive. Education is needed to improve HCPs CR awareness.

Mandibular Reconstruction Using Free Fibular Flap Graft Following Excision of Calcifying Epithelial Odontogenic Tumor.

ABSTRACT: The calcifying epithelial odontogenic tumor (CEOT) is a rare benign odontogenic tumor, which usually presents with distension of affected tissues. Radiologically, the lesions are often associated with an unerupted tooth and may have spot calcification shadows. The authors report a case of a CEOT in a 48-year-old male involving the right mandibular jaw bone and mentum soft tissues. The authors performed hemimandibulectomy and enucleation followed by reconstruction of the mandible using a vascularized free fibular flap through a digital surgical technique in order to restore the patient's facial symmetry and prepare the area for functional restorations. The case illustrates who the free fibular flap graft can be used for satisfactory mandibular reconstruction and restoration of the morphology and functions.

Insights into pH-dependent transformation of gibberellic acid in aqueous solution: Transformation pathway, mechanism and toxicity estimation.

Gibberellic acid (GA3) is widely used in agriculture and maybe transfer with groundwater flow, which is an endocrine disruptor, but few studies have focused on the transformation pathway and toxicity assessment of GA3 and its products. Here, GA3 and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight (LCMS-IT-TOF) and high-performance liquid chromatography (HPLC), respectively. The results showed that the half-life of GA3 transformation in ultrapure water was 16.1-24.6 days at pH=2.0-8.0, with the lowest half-life occurring at pH=8.0 and highest half-life occurring at pH=3.3. Isomerized gibberellic acid (Iso-GA3) and gibberellenic acid (GEA) were the main transformation products with a little hydroxy gibberellic acid (OH-GA3). In North China groundwater, the mass balance of GA3 and its products was 76.2%, including Iso-GA3 (58%), GEA (7.9%), GA3 (7.3%) and OH-GA3 (3%) after reaching transformation equilibrium. Using Gaussian 09 for chemical computation, it was found that the transformation mechanism of GA3 was dependent upon the bond energy and the stereochemical feature of its molecular structure. GA3 always isomerized from the γ-lactone ring due to the lowest bond energy between the oxygen terminus of the γ-lactone ring and A ring. While GA3 and its transformation products all had developmental toxicity, the predicated LC50 (96 hr) and LD50 of the main products of GA3 were much lower than those of GA3, indicating GA3 would be transformed into higher toxicity derivatives in water environments, posing a significant health risk to humans and the environment.