Advances on BTB protein ubiquitination mediated plant development and stress response / 生物工程学报

The BTB (broad-complex, tramtrack, and bric-à-brac) domain is a highly conserved protein interaction motif in eukaryotes. They are widely involved in transcriptional regulation, protein degradation and other processes. Recently, an increasing number of studies have shown that these genes play important roles in plant growth and development, biotic and abiotic stress processes. Here, we summarize the advances of these proteins ubiquitination-mediated development and abiotic stress responses in plants based on the protein structure, which may facilitate the study of this type of gene in plants.

Related factors of abnormal body posture among urban primary school students in Yinchuan / 中国学校卫生

Objective@#To investigate the incidence and influencing factors of abnormal body posture among urban primary school students in Yinchuan City, and to provide evidence for the prevention and treatment of abnormal body posture.@*Methods@#A multi stage stratified cluster random sampling method was adopted to select 1 947 urban primary school students aged 7-12 years from 9 schools in Yinchuan City. Body Style(Model.S-8.0) instrument was used to screen abnormal body posture and questionnaire was designed to investigate related factors.@*Results@#The comprehensive body posture score of urban primary school students in Yinchuan City was(22.07±2.87), and the detection rate of abnormal posturing was 71.29%；which varied significantly by gender, age, body mass index (BMI)( χ 2=9.84, 13.47, 6.46, P <0.05). Specially, the rate of girls (73.54%) was higher than that of boys( 69.07 %); the abnormal rate of children aged 7-8(68.24%) was lower than that of 9-10(72.17%) and 11-12(73.54%); obese children (74.91%) was higher than that of overweight (72.64%) and normal weight children(70.28%). The high and low shoulders (40.73%), pelvis forward (39.39%) and X/O legs (38.57%) were the most common indicators of abnormal posture; the composition of the overall body posture abnormalities was higher in mild (54.32%) than moderate (37.82%) and severe (7.85%).Multivariate Logistic regression analysis showed that girls( OR =1.23), being older(9-10 years old OR =1.89, 11-12 years old OR = 2.48 ), overweight ( OR =1.39) and obesity( OR =2.34), occasionally participate in physical exercise ( OR =2.96), exercise duration <30 minutes daily ( OR =2.77), video duration ≥2 h daily ( OR =2.84), almost no dairy products ( OR =1.79), almost no food Fish consumption ( OR =1.77), almost no vegetables ( OR =2.14), drinking carbonated beverages daily ( OR =2.97), and sleeping time <6 h daily ( OR =2.56) were the related factors of body posture development of urban primary school students( P <0.05).@*Conclusion@#The abnormal body posture of urban primary school students in Yinchuan City is prevalent, which is related to the timely length of physical exercise, nutrition, video screen and sleep duration, and should be paid enough attention.

Physical activity of middle school students in January 2023 in Ningxia / 中国学校卫生

Objective@#To investigate physical activity status and associated factors of middle school students in Ningxia in January 2023, and to provide references for the better development of physical activity among middle school students.@*Methods@#In February 1-7,2023, a convenient sampling method was used to select 6 593 middle school students in 5 prefectural cities of Ningxia. Online questionnaires were used to investigate physical activity and its influencing factors in the previous month.@*Results@#The detection rates of sedentary behavior, light physical activity, moderate physical activity and vigorous physical activity was 92.25%, 4.66%, 2.72% and 0.38%, respectively. Multivariate Logistic regression analysis showed that being female, older age, overweight, obesity, COVID-19 infection, low to moderate family support, low to moderate level knowledge of physical activity, insufficient physical activity skills, insufficient physical activity equipment, long distance (>2.5 km or above) were associated with less physical activity ( OR=1.22, 2.47, 1.89, 1.39, 2.32, 1.20, 2.61, 1.85, 1.45, 1.23, 1.26, 1.11, 2.05, 1.77, 1.14, 1.43, P <0.05).@*Conclusion@#The poor physical activity performance of middle school students in Ningxia is related to BMI, COVID-19 infection, physical activity knowledge and skills, distance from activity places, etc. The influencing factors should be actively controlled to promote students physical health.

Research on the coordinated development of ecosystem services and well-being in agricultural and pastoral areas.

Payment for Ecosystem Services (PES) has been widely accepted as a policy tool for promoting ecological and social progress. However, PES development and implementation in traditional agricultural and pastoral areas are often more challenging than in other areas. The contradiction between ecological protection and people's livelihood development in traditional agricultural and pastoral areas is related to developing country's sustainable development strategy. Based on this, we evaluate the PES (ERCCP: the Ecological Relocation and Capital Compensation Program) program in Tianzhu County, as a case study to investigated the impact of ERCCP on the local natural and social ecosystems on a 20-year scale. The results of indicated that ERCCP has achieved "win-win" gains of restoring environment and promoting socioeconomic development: in the 10 years since ERCCP was implemented, the area of forest land and grassland increased significantly, increasing by 1135.6 ha and 919.62 ha, respectively. 57.5% of farmland was converted to grassland and 30.8% to forest, respectively. In addition, 92.2% and 7.5% of bare land were replaced by grassland and forest, respectively, indicating a gradual recovery of green land during this period. We also analyzed the effects of ERCCP on social systems, and found that the change of agro-pastoralists' attitude towards ERCCP promoted the transfer of labor force from the primary industry to the tertiary industry, accelerated the development of urbanization, and made the poor population completely out of poverty by 2020. In addition, we predict that the income level of households, the PES return on investment of local governments, and the value of regional ecosystem services will increase significantly after 2025. In this context, We establish a theoretical model to explain the win-win plan for the coordinated development of ecosystem services and regional well-being to explore the sustainability of PES and provided a typical case for the similar research area in the world, especially in the areas with the ecological fragility and poverty problems.

Simultaneous determination of 25 components in Bawei xiaobopi capsules by HPLC-QqQ-MS / 中国药房

OBJECTIVE To esta blish the method for simultaneous determination of 25 components （such as berberine ， magnoflorine and hydroxysafflor yellow A ）in Bawei xiaobopi capsules. METHODS High-performance liquid chromatography- tandem triple quadrupole mass spectrometry （HPLC-QqQ-MS）method was adopted. The determination was performed on WondaSil C18-WR column with mobile phase consisted of 0.1％ formic acid solution-methanol （gradient elution ）at the flow rate of 0.5 mL/min. The column temperature was 25 ℃，and sample size was 5 μL. Electrospray ionization source was scanned in positive and negative ion mode at the same time ，with multiple reaction monitoring. The capillary voltage was 4 000 V（+）and 2 500 V（－）. The drying gas flow rate was 11 L/min with the temperature of 300 ℃. The pressure was 15 psi. RESULTS Totally 25 components of Bawei xiaobopi capsules had good linear relationship within a certain range ，such as magnolflorine ，jatrorrhizine，berberine， palmatine，bufotenine，bufotenidine，piperine，glycyrrhizic acid ，ferulic acid ，ferulic acid 4-O-β-D-glucopyranoside，hydroxysafflor yellow A ，chlorogenic acid ，gallic acid ，chebulagic acid ，corilagin，ellagic acid ，liquiritigenin，liquiritin，rutin，quercetin， glycocholic acid ，cholic acid ，glycochenodeoxycholic acid ，glycodeoxycholic acid ，ursodeoxycholic acid （r≥0.999 0）. The limits of quantitation were 0.62-554.50 ng/mL；the limits of detection were 0.18-166.30 ng/mL.RSDs of precision ，repeatability and stability（24 h）tests were all lower than 3.00％. The recovery rates were 80％-115％（all RSDs lower than 3.00％，n＝6）. The contents of above 25 components were 16.94-20.82，3.78-5.17，9.11-11.43，0.24-0.30，0.20-0.39，0.74-1.16，0.79-0.89，3.26-3.35， 0.48-0.66，11.96-13.35，2.30-3.12，0.19-0.21，6.07-8.83，10.42-10.48，1.43-1.64，4.17-4.76，0.14-0.15，0.46-0.52，0.04，0.01， 0.59-0.63，0.20-0.23，0.02，0.15-0.16，0.01 mg/g，respectively. CONCLUSIONS Established method is simple ，sensitive and stable，and can be used for content determination of 25 components in Bawei xiaobopi capsules simultaneously.

Mechanism of Bushen Zhuyun Prescription on Improving Luteal Function of Brown Norway Rats Based on MAPKs Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the possible mechanism of Bushen Zhuyun prescription （BSZYP） to reduce the level of ovarian apoptosis in Brown Norway （BN） rats with luteal phase deficiency （LPD）. MethodFifty SPF female BN rats were randomly divided into a model group， a dydrogesterone group （0.002 g·kg-1）， and a low （4.5 g·kg-1）， a medium （9 g·kg-1）， and a high-dose （18 g·kg-1） BSZYP groups， with ten rats in each group. The rats were administrated with corresponding drugs by gavage， once a day for three estrus cycle. Western blot was used to detected the protein expression levels of c-Jun NH2 terminal kinase （JNK）， extracellular signal-regulated kinase （ERK）， phosphorylated-ERK （p-ERK）， phosphorylated-JNK （p-JNK）， p38 mitogen-activated protein kinase （p38 MAPK）， phosphorylated-p38 MAPK （p-p38 MAPK ）， B-cell lymphoma （Bcl-2）， and Bcl-2 associated X protein （Bax） in ovary. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression levels of ERK， JNK， p38 MAPK， Bax， and Bcl-2 in ovary. Enzyme-linked immunosorbent assay （ELISA） was used to detect the serum progesterone （P） and estradiol （E2） levels. Hematoxylin-eosin （HE） staining was used to observe the ovarian tissue morphology. ResultCompared with the model group， the recovery of estrus cycle of rats in all BSZYP groups had statistical significance after 1-circle administration （P<0.05）. The ovarian tissue morphology in the low-dose BSZYP group was improved， and that in the medium and high-dose BSZYP groups was significantly improved with clear follicle， less vesicular follicle and atretic follicle， and more granular layers. The number of luteum， especially the fresh luteum， in the medium and high-dose groups was increased with smooth edge and large volume. The mRNA expression level of Bcl-2 was increased in all-dose BSZYP groups， while the mRNA expression level of Bax was significantly decreased in all-dose BSZYP group （P<0.05， P<0.01）. The mRNA expression levels of JNK and p38 MAPK were significantly decreased in the high-dose BSZYP group （P<0.01）， and the mRNA expression levels of ERK were increased in the low and medium-dose BSZYP groups （P<0.05）. The protein expression level of Bcl-2 was significantly increased in the medium and high-dose BSZYP groups （P<0.01）， and the protein expression level of Bax was significantly decreased in the all-dose BSZYP groups （P<0.01）. No significant difference was observed in the protein expressions of JNK， ERK， and p38 MAPK in the BSZYP groups. The protein expression levels of p-ERK in the ovarian tissues of rats were significantly inoreased in the medium and high-dose BSZYP group （P<0.01）， p-JNK， and p-p38 MAPK in the ovarian tissues of rats were significantly decreased in the medium and high-dose BSZYP group （P<0.01）. The level of E2 was increased in all-dose BSZYP groups （P<0.05， P<0.01）， and the level of P in the medium-dose BSZYP group was increased （P<0.05）. ConclusionBSZYP improved the serum sex hormones， restored the estrous cycle， reduced atretic follicle and vesiculation， and maintained luteal morphology and function of BN rats， so as to improve luteal function and treat luteal phase deficiency. The mechanism of BSZYP may be related to reduce the level of ovarian tissue apoptosis in BN rats by regulating MAPKs signaling pathway.

[Effects of warming on radial growth of Picea crassifolia in the eastern Qilian Mountains, China]. / 升温对祁连山东部青海云杉径向生长的影响.

Tree-rings of Picea crassifolia from high (3000 m), middle (2750 m) and low (2500 m) altitudes were collected from the Xiying River basin in the eastern Qilian Mountains, with the standard chronology being established using dendrochronological methods. Results of the correlation analysis between tree-ring width index and temperature and precipitation during different periods showed that radial growth of P. crassifolia at different altitudes responded differently to climate warming in the eastern Qilian Mountains. Water and heat availability were the main limiting factors for the radial growth of P. crassifolia in the eastern part of Qilian Mountains. The growth limiting factors at different altitudes were generally the same. Before the prominent warming (1961-1986), radial growth of P. crassifolia at the three sampling altitudes was significantly negatively correlated with mean maximum temperature in July-August of the previous year and August of the current year, and significantly positively correlated with the relative humidity in June of the current year. After the prominent warming period (1986-2014), tree growth at high, middle, and low altitudes remained significantly negatively correlated with air temperature, changed from non-significantly negative to significantly positive correlation with relative humidity in February of the current year, and changed from significantly positive to non-significantly negative correlation with precipitation and relative humidity in June. Warming caused a slowing growth of P. crassifolia tree-ring at all altitudes, with the highest altitude being the most sensitive. Drought stress caused by climate warming might be the main reason for the changes of radial growth of P. crassifolia.

Urinary calcium and gross movements levels among Hui nationality children in rural area of Ningxia with establised card household / 中国学校卫生

Objective@#To investigate the urinary calcium and gross motor levels among Hui nationality children aged 3-6 years in rural Areas of Ningxia with establised card household, and to provide evidence for the improvement of urinary calcium and gross motor levels in this group.@*Methods@#Using convenient sampling method, 24 rural kindergartens in 8 poor counties in Ningxia were selected, and 358 registered Hui children were investigated and tested for urinary calcium and gross motor levels. Morning Urinary calcium was tested by using test kit. Gross Motor Development Test Scale version 3 (TGMD-3) was used to assess gross motor development in children.@*Results@#Calcium deficiency in boys and girls accounted for 23.6% and 38.6% respectively, the difference was statistically significant(χ2=6.83, P<0.01). In each age groups, the number of boys and girls with calcium deficiency was relatively high, in the corresponding total number of children, and the younger age group was obvious, and the proportion of girls was higher. In terms of the level of coarse movements, the overall scores of mobile movements, ball movements and movement development showed that the scores increased with age(F=4.39, 4.20, 4.13, 4.60, 4.80, 4.77, P<0.05). In terms of mobile action level, boys were higher than girls in 4 age groups(3.5, 4, 4.5 and 5.5 year-old groups), while in other age groups were lower than girls. In all age groups, both boys and girls showed higher mobility scores than ball skills. In terms of ball skills, the scores of girls aged 3 and boys aged 3.5-6 were higher than those of girls. In terms of overall performance, boys were higher than girls in most of age groups. In the 3-3.5 years old and 4-6 age groups, 26.6% and 56.4%, 5.3% and 11.4% of children showed delays in mobile and ball skills.No correlation between urinary calcium and gross motor level was found in the normal group and the delayed group(r=0.33, 0.37, P>0.05).@*Conclusion@#Among those 3-6 year old Hui children with established card household in Ningxia rural areas, uneven development of urine calcium and gross movements are noticed. There are a large proportion of children with calcium deficiency and gross movements development delay, active measures should be developed and be carrtied out.

[Relationship between radial growth of Abies georgei and climate factors at different altitudes on the eastern slope of Yulong Snow Mountain, China.] / çŽ‰é¾™é›ªå±±ä¸œå¡ä¸åŒæµ·æ‹”é•¿è‹žå†·æ‰å¾„å‘ç”Ÿé•¿ä¸Žæ°”å€™å› å­çš„å ³ç³».

Based on dendrochronological methods, we established residual chronologies (RES) of Abies georgei at low, middle and high altitudes with ring width data on the eastern slope of Yulong Snow Mountain. We examined the relationship between the radial growth and climate factors (temperature and precipitation) by response function analysis and redundancy analysis (RDA) to identify the key climatic factors driving the radial growth of A. georgei. The results showed that the responses of radial growth of A. georgei to climates were consistent at three altitudes, which was jointly controlled by temperature and precipitation. This consistency was related to the steep terrain of Yulong Snow Mountain, the high-altitude distribution, and shallow root characteristics of A. georgei. At all three altitudes, tree growth showed significantly positive correlation with mean temperature of the current July, mean temperature of the previous November, and precipitation of the current January, but negative correlation with precipitation of the current June. The comprehensive application of response function analysis and redundancy analysis could accurately reveal the relationship between tree growth and climatic factors along environmental gradients. Our results provided a scientific basis for climatic reconstruction and forest management in the area.

Effects of tributyrin supplementation on ruminal microbial protein yield, fermentation characteristics and nutrients degradability in adult Small Tail ewes.

Two trials were conducted to assess the effects of tributyrin (TB) supplementation on ruminal microbial protein yield and fermentation characteristics in adult sheep. In an in vitro trial, substrate was made to offer TB at 0, 2, 4, 6, and 8 g/kg on a dry matter (DM) basis and incubated for 48 hr. In an in vivo trial, 45 adult ewes were randomly assigned by initial body weight (55 ± 5 kg) to five treatments of nine animals over an 18-day period. Total mixed ration was made to offer TB to ewes at 0, 2, 4, 6, and 8 g/kg on a DM basis. The in vitro trial showed that TB enhanced apparent degradation of DM (p = .009), crude protein (p < .001), neutral detergent fiber (p = .007) and acid detergent fiber (p = .010) and increased methanogenesis (p < .001), respectively. The in vivo trial showed that TB decreased DM intake (p < .001) and enhanced rumen microbial N synthesis (p < .001), respectively. Both in vitro and in vivo trials showed that TB increased total volatile fatty acid concentration and enhanced fibrolytic enzyme activity. The results indicated that TB might exert positive effects on microbial protein yield and fermentation in the rumen.

miR-21/Sprouty1 function axis regulates the osteogenic differentiation of bone marrow mesenchymal stem cells after postmenopausal osteoporosis / 中国组织工程研究

BACKGROUND:Osteogenic differentiation is a complex process involving transcriptional and post-transcriptional regulation by multiple signaling pathways, and the specific mechanisms remain unclear. It is of great significance to study the role of critical miRNAs in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in the treatment of osteoporosis and bone defects. OBJECTIVE: To explore the regulatory ability of miR-21/Sprouty1 function axis in the osteogenic differentiation of BMSCs in patients with postmenopausal osteoporosis. METHODS:BMSCs were isolated from healthy people (H-hBMSCs) and patients with postmenopausal osteoporosis (PMOP-hBMSCs), and their osteogenic ability was compared. Expression of miR-21 and Spry1 at gene and protein levels was detected by real-time RT-PCR and western blot assay, respectively. miR-21 expression was upregulated via transfection in PMOP-hBMSCs, and the osteogenic ability and Spry1 expression of the cells were detected, while real-time RT-PCR and western blot were used to detect the expression of osteogenic marker genes, Runx2 and Osterix. RESULTS AND CONCLUSION:Compared with H-hBMSCs, PMOP-hBMSCs osteogenic ability was weakened significantly, miR-21 expression decreased, and Spry1 expression increased, indicating an inhibition to the miR-21-Spry1 function axis. Through the transfection of miR-21 and down-regulation of Spry1, the expression levels of Runx2 and Osterix were increased, and PMOP-hBMSCs osteogenic ability was partially restored.

A cone-beam CT study on alveolar bone morphology in anterior teeth area of adult skeletal Class Ⅱ mal-occlusion subjects with different vertical skeletal types / 实用口腔医学杂志

Objective:To study the alveolar bone morphology in the anterior teeth area of the skeletal Class Ⅱ malocclusion subjects with different vertical skeletal types.Methods:64 patients with skeletal Class Ⅱ malocclusion and 15 subjects with normal occlusion were included.The alveolar bone structure of the anterior teeth were observed using CBCT.Results:The labial and lingual alveolar bone height and the alveolar bone thickness of the incisors of the patients were much lower than those of the normal controls.The height of labial and lingual alveolar bone and the alveolar bone thickness of anterior teeth in high-angle subgroup were lower than those in low-angle subgroup.Conclusion:The thickness of the anterior teeth alveolar bone of skeletal Class Ⅱ malocclusion is low,espe-cially in the high-angle group.

Indirect co-culture with endothelial progenitor cells improves proliferation and apoptosis of bone marrow mesenchymal stem cells of osteoporosis rats / 中国组织工程研究

BACKGROUND:Previous studies have found that estrogen deficiency causes a reduction in the activity of bone marrow mesenchymal stem cel s (BMSCs). OBJECTIVE:To explore the effect of endothelial progenitor cel s (EPCs) on the BMSCs proliferation and apoptosis ability of osteoporosis rats. METHODS:Healthy female Sprague-Dawley rats, 6 weeks old, were enrol ed and subjected to bilateral ovariectomy to make osteoporosis models. BMSCs and EPCs were isolated using density gradient centrifugation combined with adhesion method, and identified with surface markers, cel proliferation and immunocytochemistry in vitro. We used Transwel inserts to establish EPCs and OVX-BMSCs indirect co-culture system. Control groups were OVX-BMSCs group and sham-BMSCs group in which rats were only subjected to remove the equal amount of fat tissues around the ovary. Flow cytometry was applied to detect BMSCs proliferation and apoptosis ability. RESULTS AND CONCLUSION:Compared with the control groups, the results of flow cytometry test showed that the proportion of OVX-BMSCs at S phase was significantly increased at 3 days of indirect co-culture with EPCs and the apoptosis rate was significanty reduced at 10 days of indirect co-culture with EPCs (both P<0.05). These results suggest that EPCs can promote the proliferation but inhibit the apoptosis of OVX-BMSCs.

Bone marrow mesenchymal stem cells combined with endothelial progenitor cells for repair of alveolar bone defect in ovariectomized rats / 中国组织工程研究

BACKGROUND:Numerous studies have demonstrated that estrogen can regulate the proliferation and migration of endothelial progenitor cel s (EPCs), while EPCs can also promote the function and activity of bone marrow mesenchymal stem cel s (BMSCs) in vitro. OBJECTIVE:To evaluate the ability of the BMSCs and EPCs which construct the composite cel sheet in the repair of alveolar bone defect in ovariectomized rats. METHODS:BMSCs/EPCs composite sheet, EPCs sheet and BMSCs sheet were respectively implanted into the defects of the alveolar bone in ovariectomized rats. Rats with no implantation served as control group. Repaired alveolar bone was assessed by gross examination, histological observation and micro-CT scan at 2, 4, 8 weeks after operation. RESULTS AND CONCLUSION:BMSCs/EPCs composite sheet has greater osteogensis activity and bone repair capacity than BMSCs or EPCs sheet alone.

[Effect of wound to growth of larva of host to Ophiocordyceps sinensis during artificial breeding].

To clear the effect of the wound to the growth of the larva of the host to the Ophiocordyceps sinensis, the wounds of same severity at the same position were made artificially to the larva and which were artificial fed at the same environment and condition. The results indicated that, over the winter, the survival rate of the wounded of the infection larva was lower than that of the healthy larva, but the weight had no significant difference between the wounded and the healthy larva. The survival rate of the wounded of the no infection larva was lower than that of the healthy larva, but except with black skin, the wounded larva with offwhite and dusty red had no influence on the variety of the weight. In summery, wound had no advantage to the survival rate, but had no influence to the weight. The result had provided theoretical basis to the reforming of the system of the artificial culture O. sinensis.

Retrospective analysis of craniofacial features in patients with cleidocranial dysplasia / 实用口腔医学杂志

Objective:To investigate the craniofacial features in patients with cleidocranial dysplasia (CCD).Methods:The facial features,cervical vertebral bone age and skeletal abnormalities of 8 patients with CCD were studied by analyzing facial photos,cephalo-metric and panoramic radiographs.Results:4 patients were in the early growth stage and the other 4 in the late period of development. The bossing forehead and inclined eye fissure were observed in all patients,but underdevelopment of midfaces were not obviously pres-ented in younger patients.Morphological abnormalities of craniofacial bones,such as ascending ramus,coronoid process,nasal bones and disappearence of gonial angle were observed in all patients.Conclusion:Some craniofacial malformations in patients with CCD may be presented earlier than underdeveloped midface,which can be helpful for early diagnosis of CCD.

Histological changes of pure titanium micro-implant under inflammatory stimulation and orthodontic force as well as bone remodeling / 中国组织工程研究

BACKGROUND:Implant stability is mainly influenced by peri-implant inflammatory stimulation. OBJECTIVE:To build a beagle model of peri-implantitis under orthodontic force and to observe the bone remodeling of the Beagle dog model. METHODS: Micro-implants were randomly implanted into the maxilary interradicular region at the center of the mesial and distal roots of bilateral P2, P3, P4 and M1 of Beagle dogs. One side served as a loaded micro-implant with peri-implantitis under 100 g of orthodontic force at 1, 2, 3, 4 weeks of peri-implantitis, and the force lasted for 1 month. After that, the animals were kiled to prepare specimens with micro-implants. Bone-to-implant contacts were calculated and histological changes of the bone interface under continuous orthodontic force at different stages of peri-implantitis were observed under light microscope. RESULTS AND CONCLUSION:There were a large number of inflammatory cels after micro-implants were implanted with silk thread ligation to the cervical part. Over time, inflammatory cels were gradualy diffused to the tip of micro-implant, and there were a great quantity of colagenous fibers, osteocytes and active bone remodeling. When the inflammation was diffused to the tip of micro-implant after 2 weeks of peri-implantitis, woven bones composed of newly formed trabeculae appeared, and imflammatory cels dispersed. The medulary cavity was irregular after colagen fibrils absorption, and there were 3-4 layers of osteoblasts in the bone lacunae, with active bone formation. These findings indicate that the Beagle model of pure titanium peri-implantitis under orthodontic force was successfuly built in the experiment, and bone formation became active at 2 weeks after modeling.

A three-dimensional finite element study on the temporomandibular joint based on individual occlusal contact / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To develope a three-dimensional finite element model based on the individual occlusal contact data to analyze the influence of occlusal contact on the stress distribution in the temporomandibular joint (TMJ).</p><p><b>METHODS</b>CT, cone-beam CT (CBCT), MRI and 3D scanner were used to create a three-dimensional finite element model of the stomatognathic system, which reflected the accurate morphological characteristics of the occlusal surface. The contact area was marked on the occlusal surface of the teeth based on the individual occlusal contact data obtained during the maximal volunteer clenching (MVC). Two occlusal contact conditions including normal occlusion and unilateral posterior crossbite (UPC) were constructed. The models were fixed on the contact areas to simulate the MVC condition in order to analyze the stress distribution in the TMJ.</p><p><b>RESULTS</b>The stress distribution of the TMJ was approximately symmetrical in normal occlusion, but the stress values were somewhat different. No significant difference was found in stress distribution between UPC and normal occlusion, but the values were significantly higher on the crossbite side. The maximum values of von Mises stress were 10.35, 3.82, 3.59 MPa, on condylar process, articular disk, articular fossa of the crossbite side, respectively while on the corresponding side of the normal occlusion maximum values were 7.32, 3.18, 2.84 MPa, respectively.</p><p><b>CONCLUSIONS</b>The stress distribution of the TMJ in three-dimensional finite element model which indicated the personal occlusal contact was highly sensitive to the change of the occlusal contact. The abnormal occlusal contact caused by the UPC could lead to the stress concentration of the TMJ on the crossbite side.</p>

Effects of human bone marrow cells-derived extracellular matrix on the proliferation of human periodontal ligament stem cells / 中国组织工程研究

BACKGROUND:Human bone marrow cells-derived extracellular matrix can promote proliferation of human periodontal ligament stem cells and maintain stem cellproperties. OBJECTIVE:To preliminarily investigate the effect of human bone marrow cells-derived extracellular matrix on the proliferation of human periodontal ligament stem cells. METHODS:Human periodontal ligament stem cells and bone marrow cells were separately derived from human periodontal tissue and jaw bone marrow, and human bone marrow cells-derived extracellular matrix was prepared. Human periodontal ligament stem cells were cultured and purified using limited dilution cloning method, and transmission electron microscope was used for ultrastructure observation. Human periodontal ligament stem cells at passage 2 were cultured with human bone marrow cells-derived extracellular matrix and normal culture medium (control group). The cellcounting kit-8 and flow cytometry were used to determine the proliferation potential of human periodontal ligament stem cells cultured on human bone marrow cells-derived extracellular matrix. RESULTS AND CONCLUSION:Compared with the control group, human periodontal ligament stem cells cultured on human bone marrow cells-derived extracellular matrix had a superior capacity of proliferation (P<0.05), and the cells met their morphological and biological characteristics, and grew in good conditions. Human bone marrow cells-derived extracellular matrix is a promising matrix for large-scale expanding human periodontal ligament stem cells for future use in stem cel-based therapy.

Construction of endothelial progenitor cells/bone marrow mesenchymal stem cells composite sheets / 中国组织工程研究

BACKGROUND:Many studies have showed that enough blood supply is an essential condition of bone repair and regeneration. OBJECTIVE:To construct the endothelial progenitor cells/bone marrow mesenchymal stem cells (EPCs/BMSCs) composite sheet. METHODS:After isolation and culture, EPCs and BMSCs were co-cultured directly to form EPCs/BMSCs sheet by cellsheet-inducing medium. After 10 days of induction, the sheet was investigated by gross observation, inverted microscope and hematoxylin-eosin staining. The distribution and communication of EPCs and BMSCs during the process of cellsheet induction were observed after the fluorescence labeling separately. Alkaline phosphatase assay and alizarin red staining were applied to examine the ability of osteogenic differentiation of EPCs/BMSCs sheet. RESULTS AND CONCLUSION:EPCs/BMSCs sheet was harvested after 10-day induction. Cel-cellcontact between EPCs and BMSCs could be observed during the process of the cellsheet preparation. The harvested sheet was composed of multiple layers of cells and cel-produced extracellular matrix. Alkaline phosphatase assay and alizarin red staining both demonstrated that EPCs/BMSCs sheet had good osteogenic differentiation ability. These results suggested that EPCs/BMSCs sheet can be constructed successful y, and the sheet has strong osteogenic differentiation capability in vitro, providing the foundation for the repair of bone defects.