RESUMO
Oocyte maturation and early embryonic development are key steps in the reproductive physiology of female mammals, and any error in this process can adversely affect reproductive development. Recent studies have shown that epigenetic modifications of histones play important roles in the regulation of oocyte meiosis and quality assurance of early embryonic development. Histone deacetylase 11 (HDAC11) is the smallest known member of the histone deacetylases (HDACs) family, and inhibition of HDAC11 activity significantly suppresses the rate of oocyte maturation, as well as the development of 8-cell and blastocyst embryos at the embryonic stage. This paper focuses on recent progress on the important role of HDAC11 in the regulation of mammalian oocyte maturation and early embryonic development, hoping to gain insights into the key roles played by epitope-modifying proteins represented by HDAC11 in the regulation of mammalian reproduction and their molecular mechanisms.
Assuntos
Desenvolvimento Embrionário , Histona Desacetilases , Oócitos , Animais , Oócitos/fisiologia , Desenvolvimento Embrionário/fisiologia , Histona Desacetilases/metabolismo , Histona Desacetilases/fisiologia , Histona Desacetilases/genética , Feminino , Humanos , Oogênese/fisiologia , Mamíferos/embriologia , Meiose/fisiologiaRESUMO
The secondary metabolites of marine fungi with rich chemical diversity and biological activity are an important and exciting target for natural product research. This study aimed to investigate the fungal community in Quanzhou Bay, Fujian, and identified 28 strains of marine fungi. A total of 28 strains of marine fungi were screened for small-scale fermentation by the OSMAC (One Strain-Many Compounds) strategy, and 77 EtOAc crude extracts were obtained and assayed for cancer cell inhibition rate. A total of six strains of marine fungi (P-WZ-2, P-WZ-3-2, P-WZ-4, P-WZ-5, P56, and P341) with significant changes in cancer cell inhibition induced by the OSMAC strategy were analysed by UPLC-QTOF-MS. The ACD/MS Structure ID Suite software was used to predict the possible structures with inhibitory effects on cancer cells. A total of 23 compounds were identified, of which 10 compounds have been reported to have potential anticancer activity or cytotoxicity. In this study, the OSMAC strategy was combined with an untargeted metabolomics approach based on UPLC-QTOF-MS to efficiently analyse the effect of changes in culture conditions on anticancer potentials and to rapidly find active substances that inhibit cancer cell growth.
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Fungos , Metabolômica , Cromatografia Líquida de Alta Pressão , Fungos/metabolismo , FermentaçãoRESUMO
In order to identify the contamination and health risks of heavy metals in agricultural soils, a total of 56 surface soil samples (0-20 cm) were collected around a Pb-Zn smelter in Yunnan Province, and six heavy metals (Pb, Cd, Zn, As, Cu, and Hg) and pH were analyzed to assess heavy metal status, ecological risk, and probabilistic health risk. The results revealed that the average contents of six heavy metals (Pb:4413.93 mg·kg-1, Cd:6.89 mg·kg-1, Zn:1672.76 mg·kg-1, As:44.45 mg·kg-1, Cu:47.61 mg·kg-1, and Hg:0.21 mg·kg-1) were higher than their background values in Yunnan Province. Cd had the highest mean geo-accumulation index (Igeo) of 0.24, the highest mean pollution index (Pi) of 30.42, and the greatest average ecological risk index (Er) of 1312.60, indicating that Cd was the primary enriched and highest-ecological risk pollutant. The mean hazard index (HI) through exposure to six HMs was 2.42E-01 and 9.36E-01 for adults and children, respectively, with 36.63% of HI values for children exceeding the risk threshold of 1. Moreover, the mean total cancer risks (TCR) were 6.98E-05 and 5.93E-04 for adults and children, respectively, with 86.85% of TCR values for children exceeding the guideline value of 1E-04. The probabilistic health risk assessment suggested that Cd and As were the main contributors for the non-carcinogenic risks and carcinogenic risks. This work will provide scientific reference for the precise risk management and effective remediation strategy of soil heavy metal pollution in this study area.
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Mercúrio , Metais Pesados , Poluentes do Solo , Criança , Adulto , Humanos , Zinco , Solo/química , Chumbo , Cádmio , Monitoramento Ambiental , Poluentes do Solo/análise , China , Metais Pesados/análise , Medição de Risco , Receptores de Antígenos de Linfócitos TRESUMO
Textile dyes and dye industrial effluents are widely known for esthetic and toxicity problems. The toxicity of three direct dyes, Direct Blending Rebine (D-BLL), Direct Blending Scarlet (D-GLN), and Direct Blending Yellow (D-3RNL), were examined by the antioxidase and lipid peroxide index. Fish (Carassius auratus) were exposed to 100mg/L test compounds or injected with 200µg/kg corresponding dyes, and then samples of liver were collected at different times (0.5, 1, 3, 5, 7, 10, 13, 17 and 22d ) for analysis of superoxide dismutase (SOD), catalase (CAT), and contents of malondialdehyde (MDA). There is an obvious difference between two poisoning conditions and results indicated injection pattern have a more sensitive response. Besides, SOD, CAT and MDA levels displayed different variation trend following the prolonged duration, implying that dye metabolism generated less toxic or more active substance. The comparison among their intensity of enzyme inhibition showed that the toxicity order is D-BLL>D-GLN>D-3RNL. Additionally, three direct dye molecules were optimized based on the quantum mechanical charge density of a solute molecule interacting with a continuum description of the solvent (SMD) of Self-consistent Reaction Field Theory (SCRF) on B3LYP/LAN2BM level and the stable configurations were obtained. Wiberg bond orders were analyzed and atom in molecule (AIM) 2000 program was employed to estimate the interaction between atoms. The possible degradation pathways and toxicities were speculated based on the computations. The calculation is consistent with the experimental results and analysis.
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Bioensaio , Corantes/toxicidade , Carpa Dourada/fisiologia , Fígado/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Ativação Enzimática/efeitos dos fármacos , Carpa Dourada/metabolismo , Fígado/enzimologia , Malondialdeído/análise , Modelos Químicos , Superóxido Dismutase/metabolismoRESUMO
Phenol oxidase plays an important role in the degradation of soil organic matter. There was no standard method to determine soil phenol oxidase activity. To fill such knowledge gap, we investigated the effects of substrate type, pH, soil storage conditions, storage time, substrate concentration, water-soil ratio, incubation time and incubation temperature on soil phenol oxidase activity in three different subtropical forest soils developed on sandstone. The pH of extraction buffers significantly affected the phenol oxidase activity. Using 2,2'-azinobis-(-3-ethylbenzo-thiazoline-6-sulfononic acid)-diammonium salt (ABTS) as substrate acquired higher oxidase activity and was applicable to wider pH range than using 3-(3,4-Dihydroxyphenyl)-L-alanine (L-DOPA) as substrate, indicating that ABTS was more suitable as a substrate for measuring phenol oxidase activity in acidic soils of subtropical forests. The storage condition significantly affected phenol oxidase activity. The phenol oxidase activity declined with time in all the three types of soil. The decreasing rate was air-dried > 4 â refrigerated > -20 â frozen > -80 â frozen, suggesting that the frozen storage method was better than others in maintaining soil phenol oxidase activity if the determination of phenol oxidase activity in fresh soil samples cannot be immediately done. Substrate concentration, water-soil ratio, and incubation time and temperature all affected the activity of soil phenol oxidase. The condition of soil: buffer ratio of 1:100, 2 mmol·L-1 concentration of ABTS with an incubation time of 4 h at 25-30 â was optimal for measuring phenol oxidase activity in acidic soils of subtropical forests, with high repeatability and sensitivity.
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Monofenol Mono-Oxigenase , Solo , China , Florestas , Microbiologia do Solo , ÁguaRESUMO
Non-muscle invasive bladder cancer (NMIBC) is a major type of bladder cancer with a high incidence worldwide, resulting in a great disease burden. Treatment and surveillance are the most important part of NIMBC management. In 2018, we issued "Treatment and surveillance for non-muscle-invasive bladder cancer in China: an evidence-based clinical practice guideline". Since then, various studies on the treatment and surveillance of NMIBC have been published. There is a need to incorporate these materials and also to take into account the relatively limited medical resources in primary medical institutions in China. Developing a version of guideline which takes these two issues into account to promote the management of NMIBC is therefore indicated. We formed a working group of clinical experts and methodologists. Through questionnaire investigation of clinicians including primary medical institutions, 24 clinically concerned issues, involving transurethral resection of bladder tumor (TURBT), intravesical chemotherapy and intravesical immunotherapy of NMIBC, and follow-up and surveillance of the NMIBC patients, were determined for this guideline. Researches and recommendations on the management of NMIBC in databases, guideline development professional societies and monographs were referred to, and the European Association of Urology was used to assess the certainty of generated recommendations. Finally, we issued 29 statements, among which 22 were strong recommendations, and 7 were weak recommendations. These recommendations cover the topics of TURBT, postoperative chemotherapy after TURBT, Bacillus Calmette-Guérin (BCG) immunotherapy after TURBT, combination treatment of BCG and chemotherapy after TURBT, treatment of carcinoma in situ, radical cystectomy, treatment of NMIBC recurrence, and follow-up and surveillance. We hope these recommendations can help promote the treatment and surveillance of NMIBC in China, especially for the primary medical institutions.
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Neoplasias da Bexiga Urinária , Administração Intravesical , Vacina BCG/uso terapêutico , Cistectomia , Humanos , Invasividade Neoplásica , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/terapiaRESUMO
OBJECTIVE: To explore the effect of endemic fluoride poisoning caused by coal burning on the oxidative stress in rat testis. METHODS: Totally 40 male SD rats were equally randomized into four groups control group, low fluorosis group, middle fluorosis group, and high fluorosis group. Rats in all three fluorosis groups were fed with corn dried by burning coal obtained from endemic fluorosis areas with high fluoride, and thus the animal models of fluorosis were established. After 120 and 180 days, all the rats were sacrificed. Testis tissues were stained with hematoxylin eosin and observed under light microscope. The malonaldehyde (MDA) content, superoxide dismutase (SOD) activity, total nitric oxide synthase (TNOS), and inducible nitric oxidase synthase (iNOS) were measured by biochemical methods in the testis tissues. The content of NaF in testis was measured by fluorine selective electrode. RESULTS: The rat fluorosis models were successfully established. The fluoride content in testis was significantly increased in all the fluorosis groups(P<0.01). Testicular structures were damaged in all of fluoride groups. The TNOS, iNOS activities, and MDA content of each fluoride group were significantly higher than that of the control group on day 120 and 180 (P<0.05 or 0.01 ). The TNOS, iNOS activities, and MDA content significantly increased in a dose dependent manner (P<0.05 or 0.01). The SOD activities significantly decreased in all the fluoride groups (P<0.05 or 0.01). CONCLUSIONS: Endemic fluoride poisoning caused by coal burning can cause disorders in the oxidative system and antioxidative system in rat testis. The oxidative stress may play an important role in the fluorides induced reproductive toxicity in male rats.
Assuntos
Intoxicação por Flúor/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Testículo/metabolismo , Animais , Carvão Mineral/toxicidade , Modelos Animais de Doenças , Intoxicação por Flúor/patologia , Masculino , Malondialdeído/metabolismo , Óxido Nítrico Sintase/metabolismo , Ratos , Ratos Sprague-Dawley , Testículo/efeitos dos fármacos , Testículo/patologiaRESUMO
OBJECTIVE: To study the influence and distribution in proximal tubule epithelial cells with the expressions of CD133 and CD34 in a rat model so as to provide a study basis for renal adult stem cell. METHODS: The kidney ischemia/reperfusion model was established by blocking the bilateral renal arteries for about 50 min and recovering the renal perfusion of blood. Then the rat kidneys were extracted at Days 3, 5 and 7 post-modeling. After a series of special treatment, immunohistochemical staining was used to show the distribution and expression intensity of KIM-1, Brdu antigen, CD34 and CD133 antigens in cells with the elapsing of time. RESULTS: As compared with control group, the KIM-1 and CD133 antigens were present in cortex renis while the CD34 and Brdu antigens were distributed in parts of medulla renis and juncture of cortex-medulla renis. The expression density value of KIM-1 and CD133 antigens rose for the first 3 days then declined afterward (40.3% ± 3.2%, 57.5% ± 3.8%, 24.3% ± 1.4%). Otherwise the expression density value of CD 34 antigen declined (56.0% ± 4.8%, 44.2% ± 2.2%, 28.8% ± 1.0%) and Brdu antigen showed an upward trend at post-operation (10.0% ± 1.1%, 36.0% ± 4.2%, 48.8% ± 5.0%). CONCLUSION: After ischemia/reperfusion injury in kidney, the expression rates of CD133 and KIM-1 antigen rise obviously in cortex renis. And the D34 and Brdu antigens show a similar trend in medulla renis. The result indicates that the phenomenon of proliferation and differentiation may appears in kidney proximal tubule and migrate from the region of medulla renis to cortex renis. The participating cells not only possess the strong proliferation and repairing ability of stem/progenitor cells, but also can expresses the CD34 and CD133 antigens. Thus it is may provide a study basis for the tissue reconstruction of nephron and research in the field of kidney adult stem cell.
Assuntos
Antígenos CD34/metabolismo , Antígenos CD/metabolismo , Glicoproteínas/metabolismo , Túbulos Renais Proximais/metabolismo , Peptídeos/metabolismo , Traumatismo por Reperfusão/metabolismo , Antígeno AC133 , Animais , Células Epiteliais/metabolismo , Feminino , Masculino , Ratos , Ratos WistarRESUMO
OBJECTIVE: To evaluate the feasibility and safety of a new laparoscopic technique for resection of a fibrous ring and extravascular stent implantation in patients with nutcracker syndrome (NCS). MATERIAL AND METHODS: We retrospectively reviewed data of 5 patients diagnosed with NCS between March 2010 and February 2016. The mean age of the patients (4 male and 1 female) was 34 years (range, 28-40 years). All 5 patients underwent laparoscopic resection of the narrow fibrous ring around the left renal venous (LRV) and for extravascular stent implantation in the LRV for management of NCS. RESULTS: The average operating time was104 minutes and the average blood loss during surgery was 59 mL. The average length of the postoperative hospital stay was 6 days (range, 4-8 days). In all 5 patients, the symptoms of macroscopic hematuria started decreasing gradually and resolved after surgery. Postoperative computed tomography showed that the blood outflow from the LRV was smooth. The ratio of the dilated segment's inner diameter to the diameter of the strictured segment decreased from 3.4 to 9.5, preoperatively to 1.1-2.0, postoperatively. The mean follow-up period was 17.6 months (range, 8-24 months).One patient's varicocele was cured and symptoms in all 5 patients resolved after surgery. None of the patients showed symptom recurrence. CONCLUSION: Laparoscopic surgery, for the placement of an extravascular stent and resection of the fibrous ring around the end of the LRV outflow to the inferior vena cava appears feasible and safe and offers an alternative minimally invasive for the management of NCS.
Assuntos
Laparoscopia , Implantação de Prótese/métodos , Síndrome do Quebra-Nozes/cirurgia , Stents , Adulto , Estudos de Viabilidade , Feminino , Humanos , Laparoscopia/efeitos adversos , Masculino , Implantação de Prótese/efeitos adversos , Estudos Retrospectivos , Procedimentos Cirúrgicos Vasculares/métodosRESUMO
Three dimensional (3D) bioprinting, which involves depositing bioinks (mixed biomaterials) layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco's Modified Eagle's Medium at 37°C for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10-5-1 × 10-3 S/cm, while stability was 66.67%. A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe EdU-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100ß immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.
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Understanding the shape of superior talar dome is essential for a better size compatibility between talar component of ankle implant and bone. The purpose of this study was to determine whether there were gender variations in (1) width (TW) and length (TL) of talus, as well as anterior width (DAW), middle width (DMW), posterior width (DPW), and length (DL) of superior talar dome; (2) differences between the DAW, DMW, and DPW; (3) the ratios between these parameters. Fifty-one cadaveric ankle specimens were included. Two observers measured all the specimens using vernier caliper. Intraclass correlation coefficients (ICCs) were used for intraobserver and interobserver reliability analysis and the reliability was thought to be good if the ICC>0.75. A two-tailed unpaired t-test or the rank-sum test was used to investigate gender variations. A single-factor ANOVA was utilized to identify the differences between the width of the superior talar dome surface and p value of <0.05 was considered significant. Intraobserver and interobserver reliability were good. Significant gender variations were found, in which TW, TL, DAW, DMW, DPW, and DL of female specimens were much smaller than those of male. The width of talar dome linearly decreased from DAW to DPW; however, the linearly decreased rate from anterior to posterior width was bigger in female. Moreover, significant differences were found in DAW/DPW, DMW/DPW, DL/DAW, DL/DMW, and DL/DPW between male and female. Based on our result, there was no difference in the 2D shape of the whole talus instead gender variation existed in the 2D shape of superior talar dome between male and female. The current 2D data could contribute to figure out more suitable size of talar component for Chinese population and might indicate a gender-specific shape of bone-implant interface, which could reduce the potential bone-component incompatibility when performing ankle replacement using standard component.
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Tálus/anatomia & histologia , Articulação do Tornozelo , Cadáver , China , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Caracteres SexuaisRESUMO
Tamoxifen citrate, as the first line of treatment for infertile men with idiopathic oligozoospermia, was proposed by the World Health Organization (WHO), and testosterone undecanoate has shown benefits in semen values. Our objective was to assess the effectiveness of treatment with tamoxifen citrate and testosterone undecanoate in infertile men with idiopathic oligozoospermia, and whether the results would be affected by polymorphisms of CYP2D6*10. A total of 230 infertile men and 147 controls were included in the study. Patients were treated with tamoxifen citrate and testosterone undecanoate. Sex hormone, sperm parameters, and incidence of spontaneous pregnancy were detected. There were no significant differences between the control and patient groups with respect to CYP2D6*10 genotype frequencies (P>0.05). The follicle-stimulation hormone (FSH), luteinizing hormone (LH), and testosterone (T) levels were raised, and sperm concentration and motility were increased at 3 months and became significant at 6 months, and they were higher in the wild-type allele (C/C) than in the heterozygous variant allele (C/T) or homozygous variant allele (T/T) subgroups (P<0.05). In addition, the percentage of normal morphology was raised at 6 months, and represented the highest percentage in the C/C subgroup (P<0.05). The incidence of spontaneous pregnancy in the C/C subgroup was higher than that in the C/T or T/T subgroups (P<0.01). This study showed that the CYP2D6*10 variant genotype demonstrated worse clinical effects in infertile men with idiopathic oligozoospermia.
Assuntos
Citocromo P-450 CYP2D6/genética , Oligospermia/tratamento farmacológico , Oligospermia/genética , Polimorfismo Genético , Tamoxifeno/administração & dosagem , Testosterona/análogos & derivados , Adulto , Substituição de Aminoácidos , Estudos de Casos e Controles , Citocromo P-450 CYP2D6/metabolismo , Quimioterapia Combinada , Feminino , Hormônio Foliculoestimulante/sangue , Frequência do Gene , Humanos , Hormônio Luteinizante/sangue , Masculino , Oligospermia/enzimologia , Polimorfismo de Nucleotídeo Único , Gravidez , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Testosterona/administração & dosagem , Testosterona/sangue , Resultado do Tratamento , Adulto JovemRESUMO
Polyhydroxylated dibenzofuran (PHODF) is an important degradation product of polychlorinated dibenzofuran (PCDF). Four types of hydrogen bonds (the one between a hydroxyl and the oxygen atom in the matrix, between hydroxyls at ortho positions, between the oxygen atom of hydroxyl at position 1 and the hydrogen atom of the matrix at position 9, and between hydroxyls at positions 1 and 9) exist in PHODFs. The energies of the hydrogen bonds were ascertained by comparing the two configurational isomers as approximately 8-11 kJ mol⻹, 16-21 kJ mol⻹, 5-8 kJ mol⻹ and 23-25 kJ mol⻹, respectively. An experiment was designed to verify the bond energies, and the entrance geometry on main paths was studied by AIM 2000 program. The most stable in each group of configurational isomers was ascertained on the basis of evaluating the effect of hydrogen bonds. Their thermodynamic properties (standard state entropy S°, standard enthalpy Δ(f)H° and standard Gibbs energy of formation Δ(f)G°) were calculated from the combination of density functional theory (DFT) at B3LYP/6-311G** level and isodesmic reactions. Octanol/water partition coefficients (log K(ow)) were calculated on line with molinspiration methodology based on group contributions. The number and position of hydroxyl substitution (N(PHOS)) can be a good indicator of these properties for all stable PHODF congeners. The configurations most likely to form are those with a hydrogen bond (Type IV). How intramolecular hydrogen bond influences ionization was also investigated and the first-order ionization constant for each stable conformation was obtained with the self-consistent reaction field (SCRF) method.
Assuntos
Benzofuranos/química , Hidrogênio/química , Radical Hidroxila/química , Oxigênio/química , Água/química , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Hidroxilação , Modelos Moleculares , Conformação Molecular , TermodinâmicaRESUMO
Polyhydroxylated dibenzo-p-dioxins (PHODDs) are important metabolic and synthetic products of polychlorinated dibenzo-p-dioxins (PCDDs). Two types of hydrogen bonds exist in PHODD molecules: one between a hydroxyl group (HO) and an oxygen atom of the ether bond, and the other between two ortho hydroxyls of a benzene ring. By fully optimized calculation with density functional theory (DFT), their bond energies were ascertained to be approximately 9-14 kJ/mol and 15-19 kJ/mol respectively by the comparison of standard Gibbs energy of formation (Δ(f)G(θ)) between different molecules, which was experimentally verified. The two types of hydrogen bonds affect the hydrophilicity and stability of the molecules. The torsional potential of hydroxyls and the orientation making the congener most stable were obtained. The octanol-water partition coefficients (logK(ow)s) were calculated based on the group contribution method, and the standard state entropy (S(θ)), standard enthalpy (Δ(f)H(θ)) of formation and Δ(f)G(θ) were obtained from the combination of DFT calculation and isodesmic reaction for the stable PHODD congeners. The number and position of hydroxyl substitution (N(PHOS)) were employed as descriptors to establish quantitative structure-property relationship (QSPR) models. Although the hydrophilicity of PHODDs increases with the number of hydroxyl groups, it is impaired by the intramolecular hydrogen bonds. The logK(ow)s of PHODDs are much smaller than those of PCDDs, and the variation trend with the number of substituents is different. In addition, the relative stability order of PHODD congeners was theoretically proposed, which is quite different from that of PCDDs. Considering the ionization in water, first-order ionization constants of PHODDs were calculated according to the results of SMD method of Self-Consistent Reaction Field Theory (SCRF), and they were influenced by the hydrogen bonds.