Causal Relationship between Mitochondrial Biological Function and Periodontitis: Evidence from a Mendelian Randomization Study.

A growing number of studies indicate that mitochondrial dysfunction serves as a pathological mechanism for periodontitis. Therefore, this two-sample Mendelian randomization (MR) study was carried out to explore the causal associations between mitochondrial biological function and periodontitis, because the specific nature of this causal relationship remains inconclusive in existing MR studies. Inverse variance weighting, Mendelian randomization-Egger, weighted mode, simple mode, and weighted median analyses were performed to assess the causal relationships between the exposure factors and periodontitis. The results of the present study revealed a causal association between periodontitis and medium-chain specific acyl-CoA dehydrogenase (MCAD), malonyl-CoA decarboxylase (MLYCD), glutaredoxin 2 (Grx2), oligoribonuclease (ORN), and pyruvate carboxylase (PC). Notably, MCAD and MLYCD are causally linked to periodontitis, and serve as protective factors. However, Grx2, ORN, and PC function as risk factors for periodontitis. Our study established a causal relationship between mitochondrial biological function and periodontitis, and such insights may provide a promising approach for treating periodontitis via mitochondrial regulation.

Mesenchymal stem cell-derived extracellular vesicles for treatment of bone loss within periodontitis in pre-clinical animal models: a meta-analysis.

BACKGROUND: Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) represent an effective and promising strategy for periodontitis, although studies remain pre-clinical. Herein, a meta-analysis was conducted to assess the efficacy of MSC-EVs in animal models of periodontitis. METHODS: The PubMed, Web of Science, and Embase electronic databases were searched up to Dec 2022 to retrieve preclinical studies examining the use of MSC-EVs for periodontitis treatment. Meta-analyses and sub-group analyses were performed to assess the effect of MSC-EVs on Bone Volume/Total Volume (BV/TV) or the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) in pre-clinical animal models of periodontitis. RESULTS: 11 studies published from Mar 2019 to Oct 2022 met the inclusion criteria. Overall, MSC-EVs contributed to periodontal bone regeneration in the inflammatory bone loss area due to periodontitis, as represented by a weighted mean difference (WMD) of 14.07% (95% CI = 6.73, 21.41%, p < 0.001) for BV/TV and a WMD of -0.12 mm (95% CI= -0.14, -0.11 mm, p < 0.001) for CEJ-ABC. However, sub-analysis suggested that there was no significant difference in CEJ-ABC between studies with bioactive scaffolds and studies without bioactive scaffolds (p = 0.60). CONCLUSIONS: The present study suggests that MSC-EVs may represent an attractive therapy for the treatment of inflammatory bone loss within periodontitis.

Euphatexols C - G, five new triterpenoids from the latex of Euphorbia resinifera.

Five new triterpenoids named as euphatexols C - G (1-5) were isolated from the latex of Euphorbia resinifera. Their chemical structures were determined by extensive spectroscopic analysis, including IR, HRMS, 1 D and 2 D NMR data. Compounds 1-5 showed moderate anti-inflammatory activity with IC50 values of 22.30, 48.04, 21.89, 38.15 and 41.15 µM, respectively.

[Four new lanostane triterpenoids from latex of Euphorbia resinifera].

Four new lanostane triterpenoids, 3ß-hydroxy-12α-methoxylanosta-7,9(11),24-triene(1), 3ß-hydroxy-12α-methoxy-24-methylene-lanost-7,9(11)-dien(2), 3,7-dioxo-lanosta-8,24-diene(3), and 3,7-dioxo-24-methylene-lanost-8-en(4), were isolated from the latex of Euphorbia resinifera with a variety of chromatography methods. Their structures were elucidated based on spectroscopic data and/or comparison with the data reported in previous research. Compounds 1, 2, and 4 showed moderate inhibition of LPS-induced NO production by RAW264.7, with IC_(50) of 30.4, 37.5, and 28.3 µmol·L~(-1), respectively.

Therapeutic Delivery of Polymeric Tadpole Nanostructures with High Selectivity to Triple Negative Breast Cancer Cells.

Targeted delivery of therapeutic drugs using nanoparticles to the highly aggressive triple negative breast cancer cells has the potential to reduce side effects and drug resistance. Cell entry into triple negative cells can be enhanced by incorporating cell binding receptor molecules on the surface of the nanoparticles to enhance receptor-mediated entry pathways, including clatherin or caveolae endocytosis. However, for highly aggressive cancer cells, these pathways may not be effective, with the more rapid and high volume uptake from macropinocytosis or phagocytosis being significantly more advantageous. Here we show, in the absence of attached cell binding receptor molecules, that asymmetric polymer tadpole nanostructure coated with a thermoresponsive poly(N-isopropylacrylamide) polymer with approximately 50% of this polymer in a globular conformation resulted in both high selectivity and rapid uptake into the triple breast cancer cell line MDA-MB-231. We found that the poly(N-isopropylacrylamide) surface coating in combination with the tadpole's unique shape had an almost 15-fold increase in cell uptake compared to spherical particles with the same polymer coating, and that the mode of entry was most likely through phagocytosis. Delivery of the tadpole attached with doxorubicin (a prodrug, which can be released at pHs < 6) showed a remarkable 10-fold decrease in the IC50 compared to free doxorubicin. It was further observed that cell death was primarily through late apoptosis, which may allow further protection from the body's own immune system. Our results demonstrate that by tuning the chemical composition, polymer conformation and using an asymmetric-shaped nanoparticle, both selectivity and effective delivery and release of therapeutics can be achieved, and such insights will allow the design of nanoparticles for optimal cancer outcomes.

Rational Design of Multifunctional Polymeric Nanoparticles Based on Poly(l-histidine) and d-α-Vitamin E Succinate for Reversing Tumor Multidrug Resistance.

A multifunctional nanoparticulate system composed of methoxy poly(ethylene glycol)-poly(l-histidine)-d-α-vitamin E succinate (MPEG-PLH-VES) copolymers for encapsulation of doxorubicin (DOX) was elaborated with the aim of circumventing the multidrug resistance (MDR) in breast cancer treatment. The MPEG-PLH-VES nanoparticles (NPs) were subsequently functionalized with biotin motif for targeted drug delivery. The MPEG-PLH-VES copolymer exerts no obvious effect on the P-gp expression level of MCF-7/ADR but exhibited a significant influence on the loss of mitochondrial membrane potential, the reduction of intracellular ATP level, and the inhibition of P-gp ATPase activity of MCF-7/ADR cells. The constructed MPEG-PLH-VES NPs exhibited an acidic pH-induced increase on particle size in aqueous solution. The DOX-encapsulated MPEG-PLH-VES/biotin-PEG-VES (MPEG-PLH-VES/B) NPs were characterized to possess high drug encapsulation efficiency of approximate 90%, an average particle size of approximately 130 nm, and a pH-responsive drug release profile in acidic milieu. Confocal laser scanning microscopy (CLSM) investigations revealed that the DOX-loaded NPs resulted in an effective delivery of DOX into MCF-/ADR cells and a notable carrier-facilitated escape from endolysosomal entrapment. Pertaining to the in vitro cytotoxicity evaluation, the DOX-loaded MPEG-PLH-VES/B NPs resulted in more pronounced cytotoxicity to MCF-/ADR cells compared with DOX-loaded MPEG-PLH-VES NPs and free DOX solution. In vivo imaging study in MCF-7/ADR tumor-engrafted mice exhibited that the MPEG-PLH-VES/B NPs accumulated at the tumor site more effectively than MPEG-PLH-VES NPs due to the biotin-mediated active targeting effect. In accordance with the in vitro results, DOX-loaded MPEG-PLH-VES/B NPs showed the strongest inhibitory effect against the MCF-7/ADR xenografted tumors with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The multifunctional MPEG-PLH-VES/B nanoparticulate system has been demonstrated to provide a promising strategy for efficient delivery of DOX into MCF-7/ADR cancerous cells and reversing MDR.

Selective and Sensitive Monitoring of Cerebral Antioxidants Based on the Dye-Labeled DNA/Polydopamine Conjugates.

A simple and novel method for evaluating antioxidants in complex biological fluids has been developed based on the interaction of dye-labeled single-strand DNA (ssDNA) and polydopamine (PDA). Due to the interaction between ssDNA and PDA, the fluorescence of dye-labeled ssDNA (e.g., FITC-ssDNA, as donor) can be quenched by PDA (as acceptor) to the fluorescence "off" state through Förster resonance energy transfer (FRET). However, in the presence of various antioxidants, such as glutathione (GSH), ascorbic acid (AA), cysteine (Cys), and homocysteine (Hcys), the spontaneous oxidative polymerization reaction from DA to PDA would be blocked, resulting in the freedom of FITC-ssDNA and leading to the fluorescence "on" state. The sensing system shows great sensitivity for the monitoring of antioxidants in a fluorescent "turn on" format. The new strategy also exhibits great selectivity and is free from the interferences of amino acids, metal ions and the biological species commonly existing in brain systems. Moreover, by combining the microdialysis technique, the present method has been successfully applied to monitor the dynamic changes of the striatum antioxidants in rat cerebrospinal microdialysates during the normal/ischemia/reperfusion process. This work establishes an effective platform for in vivo monitoring antioxidants in cerebral ischemia model, and promises new opportunities for the research of brain chemistry, neuroprotection, physiological, and pathological events.

[Morphological characteristics and gene expression of Chrysomya megacephala eggs in different developmental stages].

OBJECTIVE: To research the morphological characteristics and differential gene expression of Chrysomya megacephala eggs in different developmental stages. METHODS: After C. megacephala laid eggs (0 h), the eggs were collected every 2 h until eggs hatched into larvae. The morphological characteristics of C. megacephala eggs in different developmental stages were observed by stereo microscopy and scanning electron microscopy. The total RNA of the fly eggs was extracted. The expression levels of bicoid, slalom and chitin synthase genes was determined by real-time flourescence quantitative PCR. Statistic analyses were performed with SPSS 19.0. RESULTS: Under the stereomicroscope, at 0-4 h after egg laying, the morphological change of C. megacephala eggs was not obvious. At the 6th hour after egg laying, somites were formed. After 8 hours the eggs shriveled. At the 9th hour after egg laying, the eggs hatched into larvae. The scanning electron microscope images showed that the morphological change of eggs was not obvious in the first 4 hours, the end of micropyle slightly outward, the surface around the micropyle was smooth. At the 6th hour after egg laying, the end of micropyle began to sag and irregular protrusions formed around the micropyle. At the 8th hour the end of micropyle was obviously dented. After 9 hours larvae hatched from eggs. Real-time fluorescence quantitative PCR indicated that the expression levels of bicoid, slalom and chitin synthase genes from C. megacephala eggs regularly changed with the developmental stages. There was a significant difference in threshold cycle values among the three genes (P<0.05). CONCLUSION: The morphological characteristics of C. megacephala eggs change with the development stage. The levels of gene expression in different development period of C. megacephala eggs are different.

The efficacy and safety of corticotomy and periodontally accelerated osteogenic orthodontic interventions in tooth movement: an updated meta-analysis.

BACKGROUND: The surgically facilitated orthodontic strategy has been a promising strategy for orthodontic treatment recently. Therefore, the present meta-analysis was conducted to assess the available scientific evidence regarding the clinical outcomes, including the potential detrimental effects associated with these surgical procedures, with the aim of providing much more evidence-based information for clinical practice. METHODS: An electronic search of three databases (PubMed, Cochrane, and Embase) and a manual search of relevant articles published up to May 2023 were carried out. Clinical trials (≥ 10 subjects) that utilized surgically facilitated orthodontic strategies with clinical and/or radiographic outcomes were included. Meta-analyses and sub-group analyses were performed to analyze the standardized mean difference (SMD) or weighted mean difference (WMD), and confidence interval (CI) for the recorded variables. RESULTS: Nineteen studies published from Oct 2012 to May 2023 met the inclusion criteria. Based on the analysis outcomes, corticotomy treatment significantly decreased the alignment duration (WMD: -1.08 months; 95% CI = -1.65, -0.51 months, P = 0.0002), and accelerated the canine movement (WMD: 0.72 mm; 95% CI = 0.63, 0.81 mm, P < 0.00001) compared to the traditional orthodontic group. The periodontally accelerated osteogenic orthodontic (PAOO) strategy markedly reduced the total treatment duration (SMD: -1.98; 95% CI = -2.59, -1.37, P < 0.00001) and increased the bone thickness (SMD:1.07; 95% CI = 0.74, 1.41, P < 0.00001) compared to traditional orthodontic treatment. CONCLUSION: The present study suggests that facilitated orthodontic treatment in terms of corticotomy and PAOO strategy may represent attractive and effective therapeutic strategy for orthodontic patients.

Temporomandibular disorder symptoms and their association with quality of life of dental patients in Malaysia.

OBJECTIVE: To assess the prevalence of temporomandibular disorders (TMD) and their effects on quality of life (QoL) of dental patients. METHODS: A survey consisting of two validated questionnaires was distributed to dental patients registered at the University of Malaya Faculty of Dentistry. The Fonseca Anamnestic Index (FAI) evaluates the prevalence and severity of TMD, while the Oral Health Impact Profile - Temporomandibular Disorder (OHIP-TMD) appraises the effects of TMD on oral health-related QoL. RESULTS: Out of 342 patients (aged 16 to 50 years, 45% male and 55% female) enrolled in the survey, 50.9% had varying degrees of TMD. All 7 domains of OHIP-TMD showed a statistically significant correlation with TMD severity. CONCLUSION: TMD seems to be prevalent among Malaysian dental patients. Not only does TMD affect the QoL of an individual, but the more severe the degree of reported symptoms, the poorer their perceived oral health QoL.

Magnetic amino-rich hyper-crosslinked polymers for fat-rich foodstuffs pretreatment in nontargeted analysis of chemical hazards.

Nontargeted analysis for chemical hazards is highly desirable in controlling food safety to ensure human health. As the dominating interference in fat-rich foodstuffs, lipids removal is a great challenge in sample pretreatment. Herein, diverse lipids from both animal and vegetable oils are effectively removed and 565 chemical hazards with various physicochemical properties are used for method validation. These benefits are from the designed magnetic amino-rich hyper-crosslinked core-shell polymeric composites (Fe3O4@poly(MAAM-co-EGDMA)) and the application of an auto extraction system. Among them, the amino groups are the key factors for lipid removal. Theoretical calculations, isothermal titration calorimetry (ITC), and functional monomer replacement demonstrated that the mechanisms to universally capture free fatty acids (FFAs) and triglycerides (TGs) are electrostatic interaction and supplemented by hydrogen bonding. Overall, this work highlights the great application potentials of polymeric adsorbents as sample pretreatment materials for nontargeted analysis in food safety.

Comparative study of stress characteristics around the adjacent teeth tissues during insertion of mini-screws with different insertion angles: A three-dimensional finite element study.

With a limited alveolar bone position, there is a high risk that mini-screws (MS) implants could cause damage to the adjacent teeth. To reduce this damage, the position and tilt angle of the MS must be optimized. The aim of this study was to assess the effect of MS implantation angle on the stress exerted on adjacent periodontal membrane and roots. A three-dimensional finite element model containing dentition, periodontal ligament, jaw and MS were established based on the CBCT images and MS scanning data. The MS was first inserted perpendicular to the surface of the bone at specific locations and then tilted at an angle of 10° and 20° to the mesial and distal teeth, respectively. The stress distribution in the periodontal tissue of the adjacent teeth was analyzed after MS implantation at different angles.The stress on the adjacent tooth root and periodontal ligament was most uniformly distributed when the MS was inserted vertically. It changed 9.4-97.7% when the axis of MS was tilted at 10-degree and 20-degree angles from the point of vertical insertion. The stresses experienced by the periodontal ligament and the root are similar. When the horizontal angle of the MS insertion was changed, the MS was closer to the adjacent tooth, resulting in greater stress near the PDL and root. It was recommended to insert the MS vertically into the alveolar bone surface to avoid root damage due to excessive stress.

Analysis of Risk Factors Associated with Early Childhood Caries.

Objective: To identify the main factors associated with early childhood caries by analyzing the risk factors of early childhood caries, thus providing a reference for developing prevention programs to reduce the risk of early childhood caries. Methods: We selected a total of 221 children aged 3-4 years from two kindergartens in Tongzhou District, Beijing for this study. We conducted oral examination and the caries activity test (Cariostat) on children and their parents / primary caregivers, and the parents / primary caregivers additionally answered a questionnaire survey. Based on the results, we comprehensively evaluated the caries status of children and statistically analyzed the caries-related factors to identify the relevant risk factors. Results: The mean age of children in the study children was 40.08 ± 2.65 months, with a caries prevalence rate of 54.97% and a mean caries value of 4.61. Early childhood caries was correlated with the intake frequency of sugary foods, intake of sugary foods before bedtime, frequency of tooth brushing, oral health knowledge of parents, caries susceptibility, and age of starting to brush teeth. Logistic regression analysis results showed that the intake frequency of sugary foods, oral health knowledge of parents, and caries susceptibility were the factors influencing early childhood caries, especially the intake frequency of sugary foods. Conclusion: The intake frequency of sugary foods, intake of sugary foods before bedtime, frequency of brushing teeth, oral health knowledge of parents, caries susceptibility, and age of starting to brush teeth were associated with early childhood caries. Among these, the intake frequency of sugary foods, oral health knowledge of parents, and caries susceptibility, especially the intake frequency of sugary foods, were the influencing factors.

Foxtail millet MYB-like transcription factor SiMYB16 confers salt tolerance in transgenic rice by regulating phenylpropane pathway.

R2R3-MYB transcription factors play an important role in the synthesis of phenylpropanoid-derived compounds, which in turn provide salt tolerance in plant. In this study, we found that the expression of foxtail millet R2R3-MYB factor SiMYB16 can be induced by salt and drought. SiMYB16 is localized in the nucleus and acts as a transcriptional activator. Phylogenetic analysis indicates that SiMYB16 belongs to the R2R3-MYB transcription factor family subgroup 24. Transgenic rice expressing SiMYB16 (OX16) had a higher survival rate, lower malondialdehyde content, and heavier fresh weight compared with type (WT) under salt stress conditions. The transgenic plants also had a higher germination rate in salt treatment conditions and higher yield in the field compared with wild-type plants. Transcriptome analysis revealed that the up-regulated differential expression genes in the transgenic rice were mainly involved in phenylpropanoid biosynthesis, fatty acid elongation, phenylalanine metabolism, and flavonoid biosynthesis pathways. Quantitative real-time PCR analysis also showed that the genes encoding the major enzymes in the lignin and suberin biosynthesis pathways had higher expression level in SiMYB16 transgenic plants. Correspondingly, the content of flavonoid and lignin, and the activity of fatty acid synthase increased in SiMYB16 transgenic rice compared with wild-type plants under salt stress treatment. These results indicate that SiMYB16 gene can enhance plant salt tolerance by regulating the biosynthesis of lignin and suberin.

Cytotoxicity of water-soluble mPEG-SH-coated silver nanoparticles in HL-7702 cells.

Silver nanoparticles (AgNPs) are being used widely and increasingly in various products and medical supplies due to their antibacterial activity. However, little is known about the impacts of the AgNPs. Herein, The primary purpose of this study was to investigate the cytotoxic effect of AgNPs in the human liver cell line (HL-7702). The water-soluble α-Methoxy-poly (ethylene glycol)-ω-mercapto (mPEG-SH)-coated AgNPs (40 nm) were synthesized, which showed superior stabilization and uniform dispersion in culture medium. The effect of mPEG-SH-coated silver nanoparticles on cell viability, leakage of lactate dehydrogenase (LDH), oxidative stress, mitochondrial membrane potential (MMP), and cell cycle was evaluated after the cells were treated with nanoparticles. The results showed that the coated AgNPs could be taken up by cells, decreased cell viability in dose- and time-dependent manners at dosage levels between 6.25 and 100.00 µg/mL, caused membrane damage (LDH leakage), and decreased the activities of superoxide dismutase and glutathione peroxides. The level of malondialdehyde, an end product of lipid peroxidation, was also increased in AgNPs-exposed cells. Moreover, flow cytometric analysis showed that AgNP exposure decrease MMP and cause G2/M phase arrest. Thus, our data suggest that mPEG-SH-coated AgNPs have the potential toxicity that is associated with oxidative stress, apoptosis, and DNA damage.

[Preparation and pharmacokinetics of brucine hydrogel patch].

OBJECTIVE: To investigate the effect of dose on pharmacokinetic properties of brucine hydrogel patch. METHODS: The plasma concentration of brucine was determined by HPLC. Brucine hydrogel patch was prepared and its pharmaceutical characterization was investigated. After transdermal administration of different dose brucine hydrogel patch; Plasma concentration versus time profiles were determined and pharmacokinetic parameters were calculated by DAS program. RESULTS: The pharmaceutical properties of brucine hydrogel patch were satisfactory. The AUC0-1 values were 7.24 +/- 0.61, 16.02 +/- 2.34 and 54.84 +/- 26.59 microg x h/mL after administration of 30, 60 and 180 mg/kg brucine hydrogel patch, respectively. The corresponding C(max) values were 0.73 +/- 0.23, 1.45 +/- 0.28 and 4.59 +/- 1.85 microg/mL, respectively. And the corresponding T(max) values were 8.67 +/- 2.07, 11.67 +/- 2.66 and 8.33 +/- 2.65 h, respectively. CONCLUSION: The pharmacokinetic properties of brucine do not vary with the dose of brucine hydrogel patch.

Synthesis of metal-organic framework @molecularly imprinted polymer adsorbents for solid phase extraction of organophosphorus pesticides from agricultural products.

The novel core-shell structural zeolitic imidazolate framework-8 @molecularly imprinted polymers were successfully synthesized by surface imprinting technique and used as adsorbents for solid-phase extraction of organophosphorus pesticides. The obtained hybrid composites were characterized by scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared, and their adsorbing and recognition performance were evaluated by binding experiments. The results showed that zeolitic imidazolate framework-8 @molecularly imprinted polymers presented a typically core-shell structure with molecularly imprinted shell (about 50 nm) homogeneously polymerized on the surface of zeolitic imidazolate framework-8 core, and exhibited specific recognition towards organophosphorus pesticides with fast adsorption capacity. The adsorption and desorption conditions including sample loading solvent, sample pH, washing and elution solvent were optimized. Under optimum conditions, the solid-phase extraction based on zeolitic imidazolate framework-8 @molecularly imprinted polymers combined with high liquid chromatography-tandem mass spectrometry method for determining organophosphorus pesticides was established and exhibited good linearity (R2 ≥ 0.9927) in the range of 1-200 µg/L. With spiked at three different concentration levels in agricultural products (cauliflower, radish, pear, muskmelon), the recoveries ranged from 82.5% to 123.0% with relative standard deviations lower than 8.24%. The developed method was sensitive, convenient and efficient. More importantly, this study could provide a promising strategy for designing new adsorbents with extremely fast mass transfer rate for other potential trace contaminants.

Preparation of metal-organic framework @molecularly imprinted polymers for extracting strobilurin fungicides from agricultural products.

The core-shell metal-organic framework coated with molecularly imprinted polymers (ZIF-8@MIPs) were successfully synthesized by surface imprinting technique, and applied as adsorbents for solid-phase extraction of strobilurin fungicides. The obtained hybrid complex was characterized in detail, and their adsorbing and recognition performance were evaluated. The results showed that ZIF-8@MIPs presented typically core-shell structure with MIP shell (about 20 nm), and exhibited larger adsorption capacity (102.5 mg g-1) and fast adsorption ability (only 5 min). Under the optimized conditions, a sensitive, efficient and reliable method for determining six strobilurin fungicides in different agricultural products based on ZIF-8@MIPs coupling with high performance liquid chromatography-tandem mass spectrometry was established. This method showed good linearity with correlation coefficients higher than 0.9990. With spiked at three different concentration levels in agricultural products (apple, pear, banana, Chinese cabbage, cabbage, cucumber), the good recoveries (83.5-129.0%) with relative standard deviations from 0.5 to 10.2% were obtained. The limit of detections and the limit of quantifications were 0.01-1.12 ng g-1 and 0.03-3.73 ng g-1, respectively. Those results demonstrated good potential application of ZIF-8@MIPs for enriching and separating trace strobilurin fungicides in agricultural samples.

Dynamic expression and heterogeneous intracellular location of En-1 during late mouse embryonic development.

Engrailed-1 (En-1) is a transcription factor involved in the development of the midbrain/hindbrain during mouse early embryogenesis. Although En-1 is expressed from embryogenesis to adulthood, there has been no detailed description of its expression during late mouse embryonic development. Here we report the expression pattern of En-1 in the mouse embryo from E10.5 to the neonatal state. With immunohistochemistry we found that En-1 was expressed in the central nervous system (CNS) from E10.5 to the neonatal state, mostly restricted to the midbrain/hindbrain junction. Outside the CNS, En-1 is dynamically expressed in several neural crest-associated structures including the cranial mesenchyme, the mandibular arches, the vagus nerve, the dorsal root ganglia, the sympathetic ganglia, the somites, the heart and the cloaca. Additionally, we found that in the CNS, most of the En-1 was located in the nuclei, while outside the CNS, En-1 was mainly expressed in the cytoplasm. These findings provided additional evidence that En-1 may be involved in the development of neural crest cells.

[Correlation study on polymorphisms of vitamin D receptor gene in patients with periodontitis].

OBJECTIVE: To investigate the relationship between vitamin D receptor (VDR) gene polymorphisms and periodontitis. METHODS: Ninety patients with aggressive periodontitis(AgP), 34 patients with chronic periodontitis and 91 healthy controls were recruited in this study. VDR gene was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with Taq I restriction endonuclease. RESULTS: The detection frequency of Tt genotype was higher in the aggressive periodontitis patients than in the healthy controls (16.7% vs 7.7%, P>0.05). The difference between the female aggressive periodontitis patients and healthy controls (20.8% vs 4.2%, P<0.05) was statistically significant, but no difference was found between the male patients and controls (10.8% vs 11.6%, P>0.05). There was a strong association between aggressive periodontitis and Tt genotype in females (AgP patients vs healthy controls, OR=6.02). The detection frequency of Taq I ER-alpha genotypes was not statistically different between the chronic periodontitis patients and healthy controls. CONCLUSION: In female Han Chinese population, the Tt VDR genotype may be associated with aggressive periodontitis.