Development of predictive quantitative retention-activity relationship models of alkaloids by mixed micellar liquid chromatography.

The mixed micellar liquid chromatography is a mode that uses mixed micellar system of Brij35/SDS (85 : 15) as a mobile phase under adequate experimental conditions, can simulate the resting membrane potential and the conformation of the long hydrophilic polyoxyethylene chains remains unchanged. In this article, the applications of biopartitioning micellar chromatography, using mixed micellar system to describe and estimate bioactivities of alkaloids, has been focused. The BMC(Brij35/SDS)-QRAR models of half-life time, volume of distribution, plasma clearance and area under concentration-time curve were obtained using Brij35-SDS retention data. The aim is to take a look at the capability of the mixed micellar liquid chromatography model to describe and/or estimate the bioactivity of alkaloids.

Fixed orthodontic appliance therapy and its impact on oral health-related quality of life in Chinese patients.

OBJECTIVE: To determine changes in oral health-related quality of life (OHRQoL) during fixed orthodontic appliance therapy in Chinese patients. MATERIALS AND METHODS: Two-hundred fifty Chinese orthodontic patients completed six distinct intervals of the 14-item Oral Health Impact Profile (OHIP-14, Chinese version): before treatment (T0); after the placement of the fixed appliance at 1 week (T1), 1 month (T2), 3 months (T3), and 6 months (T4); and posttreatment (T5). RESULTS: The overall response rate was 88.8% (222 of 250). Significant differences of overall OHIP-14 scores could be found between any two time points (P < .001), except for between T0 and T2 (P > .05) and between T3 and T4 (P > .05). Overall scores at T1 were significantly higher than the scores at the other intervals (P < .001), with a significant change in the scores on physical pain (P < .001), psychological discomfort (P < .001), and physical disability (P < .001). Scores at T5 were lowest among the six time points (P < .001). CONCLUSIONS: Fixed orthodontic appliance therapy did affect Chinese patients' OHRQoL. Patients were considerably compromised in terms of their overall OHRQoL until approximately 1 month after insertion. The severity of the compromised condition in terms of overall OHRQoL was greatest at 1 week with the reported impact on physical pain, psychological discomfort, and physical disability. Patients' OHRQoL was better after they completed the orthodontic treatment than before or during treatment.

Mixed micellar liquid chromatography methods: modelling quantitative retention-activity relationships of angiotensin converting enzyme inhibitors.

The capability of biopartitioning micellar chromatography (BMC), using pure Brij35 solution and mixed micellar system of Brij35-SDS (85:15) as mobile phase, to describe and estimate bioactivities of angiotensin converting enzyme inhibitors at different pH has been studied. Quantitative retention-activity relationships (QRAR) in BMC were investigated for these compounds. The obtained BMC(Brij35-SDS)-QRAR models were compared with the traditional BMC(Brij35)-QRAR, and better statistically models were obtained using Brij35-SDS retention data. The superiority of BMC(Brij35-SDS)-QRAR is due to the fact that the mixed micellar mobile phase can simulate the resting membrane potential and the conformation of the long hydrophilic polyoxyethylene chains remains unchanged.

Overoxidized polypyrrole/graphene nanocomposite with good electrochemical performance as novel electrode material for the detection of adenine and guanine.

Most conducting polymer/graphene composites have excellent electrical conductivity. However, the background currents of these composites modified electrodes are much larger. In order to improve the sensitivities of these methods, it is necessary to decrease the background signal. In this paper, porous structure films of overoxidized polypyrrole/graphene (PPyox/GR) have been electrochemically coated onto glassy carbon electrode (GCE) and successfully utilized as an efficient electrode material for the quantitive detection of adenine and guanine, two of the most important components of DNA and RNA. The permselective polymer coatings with low background current could improve the selectivity and sensitivity of microelectrodes for the electropositive purine bases. The GRs into these polymers would further improve sensitivity by increasing the electroactive surface area. The electrochemical sensor can be applied to the quantification of adenine and guanine with a linear range covering 0.06-100 µM and 0.04-100 µM, and a low detection limit of 0.02 µM and 0.01 µM, respectively. More importantly, the proposed method was applied to quantify adenine and guanine in calf thymus DNA with satisfactory results.

[The effect of aminoguanidine on osteoclast in periodontal tissues during the rotation movement of teeth in rabbits].

PURPOSE: To investigate the effect of aminoguanidine on osteoclast in periodontal tissues during experimental teeth movement in rabbits. METHODS: 36 male New Zealand white rabbits were divided randomly into two groups (18 rats in each group). The rabbits of the two groups received subperiosteal injections of aminoguanidine (as AG group) and normal saline (as NaCl group) locally at 2-day intervals respectively. Rabbits were sacrificed at 3,7,14,21,28,42 days after orthodontic force application.Immunohistochemistry and TRAP enzyme stain were used to detect the expression of iNOS and observe the osteoclasts. The data was analyzed with SPSS16.0 software package. RESULTS: Collecting osteoclasts had the same change in all groups. From the 14th day till the end of the experiment, the AG group showed a significant decrease in the number of osteoclast (P<0.05)compared with the NaCl group. AG could effectively restrain the expression of iNOS in the pressure side after 21 days.The number of osteoclast was positively correlated with the proportion of iNOS in AG group (r=0.875,P<0.05). CONCLUTIONS: AG could restrain the expression of iNOS, and affect the number of osteoclast by reducing the biosynthesis of NO in rabbits.

[The expression and modulatory role of reprogramming markers on the in vivo regeneration of dental pulp and periodontal ligament tissue after injury].

PURPOSE: The purpose of this study was to investigate the expression of reprogramming markers including Oct-4, Sox2 and c-Myc in rat dental pulp and periodontal ligament tissues undergoing tissue regeneration after injury. METHODS: Lewis rat model with dental pulp and periodontal ligament injury was created. HE staining was applied to investigate the structure of newly formed dentin-pulp complex and periodontium. The distribution of Oct-4, Sox2 and c-Myc was determined by immunofluorescent staining. RESULTS: HE staining showed that newly formed dentin-pulp complex and periodontium was constructed 4 weeks after injury. Immunofluorescent staining revealed Oct-4, Sox2 and c-Myc signal was activated in the newly formed dental pulp and periodontal ligament tissue after injury compared with the normal ones. Oct-4 and Sox2 showed similar expression pattern. CONCLUSIONS: Oct-4, Sox2 and c-Myc signaling may play an important modulatory role in the dental tissue regeneration after injury. Oct-4 and Sox2 may have operative interaction whereas c-Myc may play independent role during this process.

[The effect of first premolar extraction on vertical dimension in skeletal Class I patients].

PURPOSE: To evaluate the vertical changes in Class I patients treated with first premolar extraction and to compare these changes with those without extraction. METHODS: Each group had 25 cases.One group was treated with first premolar extraction and the other without extraction. Lateral cephalograms were taken both pretreatment and posttreatment. All the films were traced and measured. To determine the vertical dimension changes due to treatment and to compare differences between the 2 groups, paired and unpaired t tests were performed with SPSS 16.0 software package, respectively. RESULTS: There was no significant difference in FH-MP, Yaxis, S-Go, S-Go/N-Me and ANS-Me/N-Me in both group after treatment. Both groups had increase in N-Me , but the change was comparatively greater in the extraction group. The extraction group showed more vertical movement of the mandibular first molars than the non-extraction group.Both groups showed mesial movement of the maxillary first molars and central incisors,but no significant difference was found. CONCLUSIONS: Both groups have increase in linear vertical dimensions. The changes in vertical dimension is greater in the extraction group, but there is no further change in the mandibular plane angle.

[Expression of matrix extracellular phosphoglycoprotein in human dental pulp cells undergoing odontoblastic differentiation].

OBJECTIVE: To investigate the expression of matrix extracellular phosphorylated protein (MEPE) in human dental pulp cells (hDPC) undergoing odontogenic induction and explore the role of MEPE in odontoblast-like differentiation. METHODS: hDPC were isolated by enzymatic digestion and preceded to odontogenic induction for 7, 14 and 21 days respectively. hDPC before induction served as controls. The expressions of MEPE, dentin sialophosphoprotein (DSPP)/dentin sialoprotein (DSP), bone sialoprotein (BSP) and collagen type I were determined by quantitative real-time RT-PCR and Western blotting. RESULTS: The mRNA levels of MEPE, DSPP, BSP and type I collagen were increased in a time-dependent manner as hDPC were induced along odontoblastic lineage. Statistical differences were detected for MEPE and BSP mRNA expressions in induced hDPC compared with control group (P < 0.001). For DSPP and type I collagen, the mRNA levels in the induced groups were (12 943.33 + or - 3805.73) and (250.55 + or - 31.86) respectively, which were significantly higher than those in control group on days 21 (P < 0.05). Western blotting also revealed the increased expressions of MEPE, DSP, BSP and type I collagen in the induced DPC. CONCLUSIONS: hDPC showed analogously temporal expressions of MEPE, DSPP/DSP, BSP and collagen type I while differentiating along odontoblast lineage. MEPE may play an important role in the odontogenic differentiation of hDPC and may be a potential marker of odontoblast-like differentiation.

[The surface antigen expression of periodontal ligament cells and dental pulp cells in vitro].

OBJECTIVE: To investigate the expression of surface antigen of human periodontal ligament cells (PDLCs) and dental pulp cells (DPCs) and the impact of ex vivo expansion to the expression of surface antigen. To provide basis of proper surface antigen for further selection of homogenous stem cell subpopulation from PDLCs and DPCs. METHODS: PDLCs and DPCs were isolated and cultured by collagenase type I and dispase. The expression of surface antigen was analyzed by immunohistochemistry and flow cytometry. RESULTS: Positive expression of STRO-1 and CD146 were observed in PDLCs and DPCs by immunocytochemistry. Similar to DPCs, PDLCs expressed mesenchymal stem cell markers STRO-1, CD146, CD29, CD44 and CD106, and displayed negative expression for CD34 at passage 1 by flow cytometry. There were no significant difference of STRO-1, CD29 and CD44 expression level between PDLCs and DPCs (P > 0.05). PDLCs expressed significantly higher level of CD106 and significantly lower level of CD146 than DPCs (P < 0.001). The proportion of STRO-1 and CD146 positive cells decreased steadily with passages in PDLCs and DPCs. CONCLUSION: PDLCs have some similar surface antigen as DPCs, and the stem cells properties of PDLCs and DPCs decreased steadily with passages.

[A proteomic analysis of human dental pulp cells undergoing odontoblast differentiation].

OBJECTIVE: To analyze the difference in protein profiles between human dental pulp cells (DPC) and odontogenic differentiated DPC by using proteomic approach. METHODS: Human DPC were induced to odontoblast differentiation and total proteins in the cell lysates before and after induction were prepared. Proteins spots were isolated by two-dimensional gel electrophoresis. DeCyder V6.0 software was applied to gel image analysis. Differential protein spots were identified by peptide mass fingerprinting technique. RESULTS: Forty-six protein spots were determined to be differentially expressed with twenty identified protein spots. Expression changes of the identified proteins revealed the involvement of various regulation mechanisms in odontoblast differentiation, such as cell cycle, cellular energy regulation and signal transduction. CONCLUSIONS: The proteomic approach is a high throughput method to screen the candidate proteins involved in odontoblast differentiation of DPC.

[Oral health-related quality of life in patients with fixed appliances].

OBJECTIVE: To assess oral health-related quality of life in patients with fixed appliances. METHODS: Orthodontic patients were asked to complete the scale of general conditions (Chinese version, questionnaire 1) and oral health impact profile (OHIP) -14 (Chinese version, questionnaire 2). Baseline data were collected at first visit and thereafter. The subjects finished questionnaire 2 at the 1st week, 4th week, 12th week and 24th week, respectively, after the fixed appliance was bonded. Data were analyzed to evaluate the various sample groups with different personal information and clinical parameters. Results were collated and analyzed using software package SPSS version 15.0. RESULTS: The most common negative effect was physical pain [55/222 (27.8%)] and psychological discomfort [40/222 (18.0%)], mainly in the first month. The total scores at five time points were 3, 10, 7, 5 and 4, respectively. No difference was found in quality of life in patients between sixth month with fixed appliance and without appliance (P > 0.05). Age and education status affected the quality of life (P < 0.001). CONCLUSIONS: Fixed orthodontic appliance therapy affected patients' oral health-related quality of life during treatment. The quality of life in the first month of treatment was mostly compromised and was improved later.

[Multilineage differentiation of human dental pulp cells and periodontal ligament cells in vitro].

OBJECTIVE: To compare the multilineage differentiation potential of human dental pulp cells (DPC) and periodontal ligament cells (PDLC) in vitro, and to identify the stem cell characteristics. METHODS: Human DPC and PDLC were isolated by enzymatic digestion. STRO-1 expression was investigated by flow cytometry. Cells were induced to odontogenic/osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation. The multilineage differentiation capacities of DPC and PDLC were evaluated by von Kossa stain, anti-osteocalcin (OCN) and anti-dentin sialoprotein (DSP) immunocytochemistry, oil red O stain, Alcian blue stain, anti-collagen type II immunocytochemistry, and real time RT-PCR. RESULTS: Colony formation was observed in DPC and PDLC, with STRO-1 positive rate of (16.5% +/- 4.2%) and (11.6% +/- 1.1%) respectively. Multilineage differentiation was demonstrated in 100% of DPC samples in contrast to 83.3% of PDLC samples. OCN, dentin sialophosphoprotein (DSPP), peroxisome-proliferator-activated receptor gamma 2 (PPARgamma2), lipoprotein lipase (LPL) and collagen type II mRNA levels in DPC and PDLC were significantly upregulated after induction (P < 0.001). There were significant differences in the ratio of upregulation of OCN and PPARgamma2 mRNAs between DPC and PDLC (P < 0.001). CONCLUSIONS: DPC and PDLC contain similar proportion of mesenchymal stem cells and possess comparable multilineage differentiation capacities.

[Analysis of distalization of lower canine by light-segmented archwire].

OBJECTIVE: To analyze the practical effect of distalization of lower cuspiud by light-segmented archwire. METHODS: 17 cases were selected. In all cases, two lower first bicuspids were extracted and lower molars were designed as reinforced anchorage. In the first half year, lower cuspids were distalized with light-segmented archwire, and lower incisors were in the physiologic drift stage. Before the treatment, three months and six months after the treatment, cephalograms and study models were recorded respectively. The data were analyzed with SPSS 10.0. RESULTS: The distance of mesiolization of the first lower molar was 1.14 mm in half a year. The distance of distalization of the lower cuspid was 5.02 mm in half a year. No significant difference was found in LM-MP and SN-MP angle. LI-NB angle was decreased by 9.57 degrees. Crowding of lower incisors was transferred from -2.55 mm to 1.08 mm. CONCLUSION: During distalization of lower cuspid by light-segmented archwire, anchorage tooth was stable, lower cuspids were distalized effectively, and lower incisors drifted towards the ideal position automatically.