From coding sequence to non-protein coding region: advances in cleft lip and palate genetic mechanism researches / 中华口腔医学杂志

With the continuous development of bioinformatics technology and precision medicine, genetic mechanism investigations of genetic diseases including cleft lip and palate (CLP) have been getting more and more attention. Researchers have focused on the coding sequence of the genome and successfully found many CLP causative mutations, but there still remain some unsolved questions. In recent years, researchers′ vision has gradually shifted to non-protein coding region of the genome. This article reviews several coding sequence mutations, non-protein coding variants and their genetic mechanisms discovered in CLP researches.

Experimental Research on Friction between Domestic Brackets and Archwires / 中国医科大学学报

Objective To study the friction between brackets and archwires and the influential factors. Methods To test the friction of six combinations of canine bracket and stainless steel archwire, and to calculate the critical contact angles for each combination. Results The friction maintains stability with slight changes when the contact angle is smaller than the critical contact angle. The friction increases linearly when the contact angle is larger than the critical contact angle. The friction of different combinations of bracket-archwire are different and the critical contact angles are also different. Conclusion The critical contact angle influences the friction between bracket and archwire significantly. The critical contact angle is relevant to both the structure of the bracket and the size of the archwire.

Machine Learning Models for Genetic Risk Assessment of Infants with Non-syndromic Orofacial Cleft / 基因组蛋白质组与生物信息学报·英文版

The isolated type of orofacial cleft, termed non-syndromic cleft lip with or without cleft palate (NSCL/P), is the second most common birth defect in China, with Asians having the highest incidence in the world. NSCL/P involves multiple genes and complex interactions between genetic and environmental factors, imposing difficulty for the genetic assessment of the unborn fetus carrying multiple NSCL/P-susceptible variants. Although genome-wide association studies (GWAS) have uncovered dozens of single nucleotide polymorphism (SNP) loci in different ethnic populations, the genetic diagnostic effectiveness of these SNPs requires further experimental validation in Chinese populations before a diagnostic panel or a predictive model covering multiple SNPs can be built. In this study, we collected blood samples from control and NSCL/P infants in Han and Uyghur Chinese populations to validate the diagnostic effectiveness of 43 candidate SNPs previously detected using GWAS. We then built predictive models with the validated SNPs using different machine learning algorithms and evaluated their prediction performance. Our results showed that logistic regression had the best performance for risk assessment according to the area under curve. Notably, defective variants in MTHFR and RBP4, two genes involved in folic acid and vitamin A biosynthesis, were found to have high contributions to NSCL/P incidence based on feature importance evaluation with logistic regression. This is consistent with the notion that folic acid and vitamin A are both essential nutritional supplements for pregnant women to reduce the risk of conceiving an NSCL/P baby. Moreover, we observed a lower predictive power in Uyghur than in Han cases, likely due to differences in genetic background between these two ethnic populations. Thus, our study highlights the urgency to generate the HapMap for Uyghur population and perform resequencing-based screening of Uyghur-specific NSCL/P markers.

Salivary exosomal PSMA7: a promising biomarker of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an intestinal immune-dysfunctional disease worldwide whose prevalence increasing in Asia including China. It is a chronic disease of the gastrointestinal tract with unknown cause. Exosomes are small vesicles in various body fluids. They have diameters of 40-120 nm, and one of their functions is long-distance transfer of various substances. In this study, we investigated the contents of salivary exosomes in patients with IBD and in healthy controls to explore a new biomarker in patients with IBD. In this study, whole saliva was obtained from patients with IBD (ulcerative colitis (UC), n = 37; Crohn's disease (CD), n = 11) and apparently healthy individuals (HC, n = 10). Salivary exosomes were extracted from samples, and the proteins within the exosomes were identified by liquid chromatograph-mass spectrometer (LC-MS/MS). The results showed that more than 2000 proteins were detected in salivary exosomes from patients with IBD. Through gene ontology analysis, we found that proteasome subunit alpha type 7 (PSMA7) showed especially marked differences between patients with IBD and the healthy controls, in that its expression level was much higher in the CD and UC groups. This exosomal protein is related to proteasome activity and inflammatory responses. So we conclude that in this research, salivary exosomal PSMA7 was present at high levels in salivary exosomes from subjects with IBD. It can be a very promising biomarker to release the patients from the pain of colonoscopy.

NELL-1:a novel highly efficient and specific growth factor / 北京大学学报(医学版)

SUMMARY Regenerationofbonetissue,aswellasothertissues,requiresinvolvementandinteraction of cells,scaffolds and relevant growth factors,among which growth factors play a crucial role in maintai-ning the stability of microenvironment.Nel-like-type 1 molecule (NELL-1 ),a novel growth factor in tis-sue engineering,has been studied intensively in recent years.Researches mainly covered gene and pro-tein structure and their expression profiling,biological function,molecular mechanisms and disease rele-vance.NELL-1 expressed in embryonic tissue is essential for growth and development of bone tissue. NELL-1 presents excellent abilities of inducing bone and cartilage regeneration,especially with high spe-cificity to chondrocyte lineage.Compared with classic osteogenic growth factor bone morphogenetic pro-tein 2 (BMP-2),the process of osteogenesis interacted with NELL-1 exhibits stronger specificity,higher bone density and fewerside effects.Furthermore,a recent study shows synergistic effects of NELL-1 and BMP-2.NELL-1 enhances the osteogenic reaction induced by BMP-2 of cells and notably declines in-flammation response caused by BMP-2.This review evaluates the current research progress of the function and application of NELL-1 by the systematic method of evidence-based medicine.

A new three-dimensional scale in the evaluation of the secondary alveolar bone grafting / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To propose a new three-dimensional method or grading scale in the evaluation of the secondary alveolar bone grafting, thus modifying the Bergland grading scale.</p><p><b>METHODS</b>A total of 40 patients (26 male, 14 female) with unilateral cleft lip and palate (UCLP), who underwent secondary alveolar bone grafting at least 3 months ago, were enrolled. Regional cone-beam CT (CBCT) scans were taken to evaluate the height and thickness of the postoperative bone bridges. A new three-dimensional grafting scale was established, including four grades respectively in alveolar height and thickness.</p><p><b>RESULTS</b>According to the new three-dimensional scale in this study, 15 grafted sites were rated grade T-I or T-II in the alveolar thickness among 18 sites of grade H-I in height, and 10 among 15 of grade H-II in height. Therefore, 25 grafted sites were considered as clinical success in the alveolar thickness (grade T-I or T-II) among 33 sites with clinical success in alveolar height (grade H-I and H-II). There were 24% of 33 sites with clinical success in height, which were considered as clinical failure in the alveolar thickness.</p><p><b>CONCLUSIONS</b>It is necessary to establish a new three-dimensional method or grading scale for evaluating the secondary alveolar bone grafting. The three-dimensional scale can take comprehensive view of the bone-grafted alveolar clefts and thus modify the Bergland grading scale.</p>

Accuracy and repeatability of computer aided cervical vertebra landmarking in cephalogram / 华中科技大学学报（医学）（英德文版）

The accuracy and repeatability of computer aided cervical vertebra landmarking (CACVL) were investigated in cephalogram. 120 adolescents (60 boys, 60 girls) aged from 9.1 to 17.2 years old were randomly selected. Twenty-seven landmarks from the second to fifth cervical vertebrae on the lateral cephalogram were identified. In this study, the system of CACVL was developed and used to identify and calculate the landmarks by fast marching method and parabolic curve fitting. The accuracy and repeatability in CACVL group were compared with those in two manual landmarking groups [orthodontic experts (OE) group and orthodontic novices (ON) group]. The results showed that, as for the accuracy, there was no significant difference between CACVL group and OE group no matter in x-axis or y-axis (P>0.05), but there was significant difference between CACVL group and ON group, as well as OE group and ON group in both axes (P<0.05). As for the repeatability, CACVL group was more reliable than OE group and ON group in both axes. It is concluded that CACVL has the same or higher accuracy, better repeatability and less workload than manual landmarking methods. It's reliable for cervical parameters identification on the lateral cephalogram and cervical vertebral maturation prediction in orthodontic practice and research.

Development and preliminary application of orthodontic friction dynamic testing apparatus / 北京大学学报(医学版)

Objective:To design and assemble an orthodontic friction prototype testing apparatus and evaluate its performance.Methods: Simulating progressive tooth tipping movement,results of the opera-ting friction trials are reported at different archwire-bracket angulation.Results: An orthodontic friction testing apparatus was designed and developed,by which the complexity of tooth movements observed with in vivo sliding mechanics was simulated and a series of in vitro friction experiments were conducted.This friction testing apparatus enables previously unattainable testing of the orthodontic archwire-bracket-ligation interface.In the passive configuration or the active configuration with second-order angulation,the friction in sliding mechanics was measured.Conclusion: The apparatus presented has the ability to allow for a high standard of basic hypothesis testing,product development and performance evaluation with relative ease.Furthermore,it will be the prototype of a computer-controlled multifunctional friction testing device in the near future.

Craniofacial characters for Angle's class Ⅱ malocclusion using Procrusts superimposition and multivariate statistics / 北京大学学报(医学版)

Objective:Cluster and discriminant analysis of the morphological characters of Angle's Class Ⅱ malocclusion was performed using Procrusts standardization.The classification of craniofacial morphology with the help of morphometry and multivariate statistics was also discussed.Methods: A total of 894 class Ⅱ patients were collected from the orthodontic department,Peking University School and Hospital of Stomatology during 1997-2000.Using Procrusts standardization and cluster analysis,the samples were divided into different groups,discrimination equations were then established.Results: The samples were divided into 11 subdivisions by Procrusts superimposition and cluster analysis.Three discrimination equations were established.The accuracy rate of cross-validated grouped cases was 80.17%.Conclusion: Procrusts standardization had certain advantages in morphological classification;cluster analysis could be used in classification of Angle class Ⅱ malocclusion;For different types,the differentiate rate was not the same;the discrimination equations was the foundation for future research.

Bone morphogenetic protein-4 regulates embryonic tongue morphogenesis / 北京大学学报(医学版)

Objective:To analyze the effect of Bone morphogenesis 4 and its antagonist Noggin on morphogenesis of tongue.Methods: Dissected rats to get embryonic day 13(E13) tongues;fed E13 tongues in standard medium,BMP4(0.03 mg/L,0.3 mg/L,1 mg/L),and the antgonist Noggin(1 mg/L,3 mg/L,10 mg/L) medium;cultured for 3 days;fixed samples,observed tongues with scanning electronic microscope(SEM);measured the whole tongue length,anterior 1/8,1/4 width and middle width of cultured tongues and analyzed data with SPSS 10.0.To further study the effects of BMP4 on epithelial and mesenchymal cell proliferation,Affi-gel blue gel beads were applied.Beads were soaked in PBS and BMP4(667 mg/L),and implanted in the E13 embryonic tongues;then after cultured in standard medium for 3 days,tongues were embedded in O.C.T.and cut into 12 ?m series sections.Ki67 was detected by immunohistochemical method.Results:(1)Whole length of tongues changed greatly(P

History and development of Chinese Orthodontics / 北京大学学报(医学版)

Orthodontics in China has experienced two important stages. At its early stage from 1950 s to 1970 s orthodontics was a division of prosthodontic department in China. There were 3 top professors in this field, who got partly training at one time or another in USA and returned to China working in Beijing Medical College, the Fourth Military Medical University and Shanghai Second Medical College. Among them, Professor Mao of Beijing Medical College was regarded as the father of Chinese Orthodontics. Removable appliance was the main tool at that stage and Prof.Mao brought forward Mao’s Classification of Malocclusion which is still used in China. The rapid developing stage began in the 1980 s when China opened its door to the world. More and more orthodontists got further training abroad and brought back advanced techniques since then. Up to now, we have already had more than one thousand of orthodontic specialists and established its own organization——the Chinese Orthodontic Society (COS), which holds domestic orthodontic meetings and organize its members to attend international meetings. Right now, almost all advanced techniques in diagnosis and treatment are adopted in China, including 3D imaging, self-ligating bracket appliance, and implant anchorage. Chinese orthodontists have started to present or publish papers in international meetings and journals and more than tiat, started to develop new app-liances, such as Driving-Force Straight Wire Appliance, which has shown advantages in treating skeletal Class Ⅲ malocclusion.

Comparative study on ordinary coordinates and standardized coordinates converted by general procrusts analyzation method in cluster analysis and discrimination analysis of AngleⅠ malocclusion / 北京大学学报(医学版)

Objective: To classify the AngleⅠ malocclusion subgroups using lateral radiographic films according to their ordinary coordinates and standardized coordinates converted by general procrusts analysis (GPA), and to compare the two kinds of classifications and their valne in diagnosis of malocclusion. Methods: 946 pretreatment lateral radiographic films of patients with Angle'I malocclusion were chosen and their ordinary coordinates were acquired via soft ware. The ordinary coordinates were then converted into standardized coordinates by GPA. All of the films were classified by cluster analysis and discrimination analysis applying the upper two kinds of coordinates respectively. Results: (1) Twenty one subgroups were identified according to the ordinary coordinates of the chosen films with the total differentiate rate of 92.7% and leave-one-out differentiate rate of 68.4% (Classification A). Correspondingly, 20 subgroups were identified according to the standardized coordinates with the two differentiate rates of 87.8% and 71.9% (Classification B). (2) If the ordinary coordinates were discriminated by Classification B, the total differentiate rate and leave-one-out differentiate rate were 79.8% and 60.2 % respectively. If the standardized coordinates were discriminated by Classification A, the two differentiate rates were 79.8% and 60.2 % respectively. (3) There were some subgroups having the similar form in Classification A and their difference mainly arose from the difference of the patient age, while there were no such subgroups like that in Classification B. (4)The proportion of the largest subgroup in total subjects is 15.9% and there were 8 subgroups having the number of subjects over 40 in Classification A, whilethe corresponding proportion and number of subgroups were 74.7% and 2 in Classification B.(5)Classification A and Classification B were both suitable to classify a new subject, but Classification B was required to standalize all of the subjects onc again, which was very complex, while Classification A was more simplified. Conclusion: Classification A and Classification B are interelated. GPA could concentrate the subjects in cluster analysis, which reduces some influence of the age to the classification, but the process to classify a new subject is very complex. Thus if quick diagnosis is needed in clinics, Classification A should be recommended, but the influence of the age should be noted.

A system for quantitatively measurement of alveolar bone density and the evaluation of its precision and validity / 北京大学学报(医学版)

Objective:To establish a system for quantitatively measuring alveolar bone density and to test its precision and validity. Methods: With the aid of computer technique, the system measured the average gray level intensity of regions of interest (ROIs) on standardized exposed direct digital periapical radiograph. To correct the variation resulting from exposure condition, an aluminum stepwedge was exposed simultaneously. By referring the image of aluminum stepwedge on each radiograph the equivalent aluminum thickness(EAT)and corrected gray level intensity(CGL)of the ROIs could be calculated as indicators of alveolar bone density. Nineteen specimens containing different amounts of hydroxy-phosphorite were radiographed. The precision of the system was tested by repeatedly measuring 2 of the specimens. The set of specimens was exposed under two different exposure time in order to test the system's validity to correct the gray level difference caused by different exposure time. Results: After repeated measurement of specimens, we found the Relative Standard Deviation(RSD) of EAT and CGL was between 0.83%-2.15%; At the level of 95%, if the difference of EAT between the two ROIs was larger than 0.05 mm or the difference of CGL was larger than 3, the content of hydroxy-phosphorite in them was different; The two sets of data during different exposure time were processed with Wilcoxon Signed Ranks Test, and the result showed effective correction of the variation caused by different exposure time. Conclusion:The precision and validity of the quantitative alveolar bone density measuring system are acceptable. The system can be used to compare alveolar bone density longitudinally and cross-sectionally.

Preliminary study of treatment mechanism and stability in deep overbite malocclusion with hyperdivergent and hypodivergent skeletal pattern / 北京大学学报(医学版)

40? or 40?)comprised 10 cases and the hypodivergent group (MP-SN

Cephalometric comparison of hard-tissue morphology between extraction and non-extraction orthodontic treatment in borderline cases / 北京大学学报(医学版)

Objective:To compare hard tissue morphology by cephalometric measurements between extraction and non extraction orthodontic treatment in borderline cases. Methods: The samples consisted of 33 cases selected as borderline cases by 5 orthodontic specialists. They were divided into 21 extraction cases (including 13 four first premolar extraction cases and 8 second premolar extraction cases) and 12 nonextraction cases by checking patients’ treatment records. Conventional cephalometric analysis was made to compare hard tissue structures before and after orthodontic treatment and the same comparison was made between two different extraction patterns. Results: No statistical difference was found on pretreatment hard tissue morphology between extraction and non extraction groups divided from borderline cases. The SNB angle of the four first premolars extraction group was smaller than that of the four second premolars extraction group by (4.0?1.3)?( P

Three-dimensional measurement of tooth inclination in cases with successful treatment / 北京大学学报(医学版)

Objective:This study aimed to observe the differences of tooth inclinations among post treatment good cases of different malocclusions and untreated normal occlusions in order to give references on clinical adjusting of tooth inclinations. Methods:157 post treatment good cases were chosen and tooth inclinations were measured on post treatment casts using YM 2115 three dimensional measurement instrument. The measurement results were compared with those of untreated normal occlusions. Results:The inclination values of upper and lower incisors of Class Ⅰ groups are most close to those of untreated normal occlusions, which of upper central and lateral incisors are 9.6? and 8.7?, and of lower central and lateral incisors are 1.1? and-1.1?. In Class Ⅱ groups, lower incisors are markedly proclined (5.6? and 2.1?) and upper incisors are similar with untreated normal occlusions. In Class Ⅲ groups, upper incisors are markedly proclined (15.2? and 12.1?) and lower incisors are markedly retroclined (-3.7? and-4.9?). Conclusion:In order to achieve normal overjet and overbite, it is necessary to adjust the inclinations of upper and lower incisors when treated Class Ⅱ and Class Ⅲ malocclusions only by the method of orthodontic treatment.

Dentoalveolar compensation for vertical craniofacial pattern after orthodontic treatment / 实用口腔医学杂志

Objective: To investigate dentoalveolar compensation for vertical craniofacial pattern after orthodontic treatment. Methods:157 post-treatment cases with normal incisor relationships and various vertical craniofacial patterns were studied. Computerized post-treatment cephalometric analysis was performed to evaluate vertical craniofacial pattern and dentoalveolar parameters. Incisor torques were measured from study models. Correlation analysis was performed between skeletal and dental measurements.Results:①There was negative correlation between post-treatment upper central incisor torque and MP-SN angle(P

Difference in dental arch form between Angle Ⅱ division 1 and normal occlusion assessed by Euclidean distance matrix analysis / 实用口腔医学杂志

Objective: To evaluate differences in dental arch forms between the subjects with Angle II division 1(AngleⅡ1 ) and those with normal occlusion. Methods:60 AngleⅡ1 patients and 60 normal occlusion subjects aged 13-17 years old were selected. Fourteen landmarks, corresponding to the cusp tips and incisor edges, were identified on the upper and lower dental casts of all subjects by YM-21115 three dimension measuring machine. Arch form differences between AngleⅡ1 and normal occlusion subjects were assessed by Euclidean distance matrix analysis (EDMA). Results:(1) In both sexes, the upper arch of AngleⅡ1 subjects was larger than that of normal occlusion (1.8% for females and 2.7% for males); and arch shape difference was also significantly different(P

Effect of changes in the anterior arch dimension on precision of Bolton analysis / 实用口腔医学杂志

Objective:To investigate whether the changes of anterior arch dimension have an impact on the precision of Bolton analysis. Methods:A mathematic-geometric model was used to evaluate the data. Results:The ideal anterior tooth size ratio may need adjustments, depending on the dimensions in radii of the upper and lower anterior dental arches. The ideal ratio is lower for dental arches with a high anterior curvature. There is a deficiency in the upper arch, a flatter anterior segment may compensate for some of the discrepancy and vice versa. Conclusion:An ideal Bolton value may not guarantee an ideal occlusion. Anterior tooth size ratio is not precise in predicting the anterior inter relationship post-treatment.

Facial growth in vertical dimension of Chinese adolescents from 13 to 15 years old with normal occlusion in Beijing / 实用口腔医学杂志

Objective:To observed the longitudinal changes of the facial growth in vertical dimension in the Chinese adolescents with normal occlusion from 13 to 15 years old.Methods:The subjects were from Beijing area and consisted of 9 males and 14 females aged 12.5-13.5 years with Class I skeletal and dental pattern and without previous orthodontic treatment. Serial 2-year- annual cephalometric radiographs were taken and digitalized. Descriptive statistics for the absolute and incremental changes of the skeletal cephalometric measurements were conducted.Results:Significant gender differences in the changes of facial growth in vertical dimension from 13 to 15 years old were observed. Most of the skeletal measurements in males showed greater value than those in females. The number of the measurements which showed gender difference increased with age. The annual incremental changes of TAFH, TPFH, LAFH, U6-PP in males and those of TPFH and RH in females from 13 to 14 years old were greater than those from 14 to 15 years, However, the average increment of L6-MP in males and that of UI-PP, LI-MP, U6-PP and OB in females from 13 to 14 years old were smaller than those from 14 to 15 years old. There was no significant gender difference in TAFH/TPFH from 13 to 15 years of age. Gender difference from 14 to 15 years old was found in the growth of dental-alveolar height. The main dento-alveolar height changes happened in lower incisors and lower molars in males and in the region of upper molars and upper incisor in females.Conclusion:The skeletal facial growth in vertical dimension from 13 to 14 year old falls into the accelerating period. After 14 years old, the growth velocity is slowed down. There are significant gender differences in the skeletal changes of facial growth in vertical dimension from 13 to 15 years old. From 14 to 15 years old, the gender differences are mainly found in the growth of the dento-alveolar height.