OBJECTIVEThis study aims to identify the crack tip stress intensity factor of the propagation process, crack propagation path, and the changes in the shape of the crack tip by the finite element method.

METHODSThe finite element model of dentino-enamel junction was established with ANSYS software, and the length of the initial crack in the single edge was set to 0.1 mm. The lower end of the sample was fixed. The tensile load of 1 MPa with frequency of 5 Hz was applied to the upper end. The stress intensity factor, deflection angle, and changes in the shape of the crack tip in the crack propagation were calculated by ANSYS.

RESULTSThe stress intensity factor suddenly and continuously decreased in dentino-enamel junction as the crack extended. A large skewed angle appeared, and the stress on crack tip was reduced.

CONCLUSIONThe dentino-enamel junction on human teeth may resist crack propagation through stress reduction.

Dental Enamel ; Dentin ; Humans ; Stress, Mechanical ; Tooth Fractures

Objective To study the tooth germ development of mouse molar in fluorosis.Methods We established an acute fluorosis model and used HE-staining after preparing specimens of different stage of mouse first molar developing tooth germ.Results The developing molars of the control fetuses were at the bell stage of odontogenesis,whereas those of the experimental population were at cap stage.The ameloblasts became shorter and lost polarity.The arrangement of ameloblasts fell into disorder at the bell of differeiational stage and secretory stage.Conclusion The developing molars of the experimental fetuses were retarded.High-dose fluoride has a strong effect in the ameloblasts at the bell of differetiational stage and secretory stage.

Referring to the rules for agricultural seed testing (GB /T 3543-1995) issued by China, the test of sampling, seed purity, weight per 1 000 seeds, seed moisture, seed viability and germination rate had been studied for screening seed quality test methods of Pesudostellaria heterophylla. The seed quality from different collection areas was measured. The results showed that at least 6.5 g seeds should be sampled and passed through 10-mesh sieve for purity analysis. The weight of 1 000 seeds was determined by using the 500-seed method. The phenotypic observation and size measurement were used for authenticity testing. The seed moisture was determined under the higher temperature (130 ± 2) degrees C for 5 hours. The seeds were dipped into 0.2% TTC sustaining 1 hour at 40 degrees C, then the viability could be determined. The break dormancy seeds were cultured on sand at 10 degrees C. K cluster analysis was applied for the data analysis, the seed quality from different collection areas grading of P. Heterophylla was described as three grades. The seed quality of each grade should reach following requirements: for first grade seeds, germination rate ≥ 86%, 1 000-grain weight ≥ 2.59 g, purity ≥ 87%, moisture ≤ 13.1%; for second grade seeds, germination rate ≥ 70%, 1 000-grain weight ≥ 2.40 g, purity ≥ 77%, moisture ≤ 14.3%; for third grade seeds, germination rate ≥ 41%, 1 000-grain weight ≥ 2.29 g, purity ≥ 76%, moisture ≤ 15.8%. The seed testing methods for quality items of P. heterophylla had been initially established, as well as the primary P. heterophylla seed quality classification standard.
Caryophyllaceae ; chemistry ; growth & development ; Germination ; Quality Control ; Seeds ; chemistry ; growth & development ; Water ; analysis

Objective Non-traumatic and posteromedial subchondral osteonecrosis of trochlea tali (NTPSOTT) is a special type of necrosis of the talus , for which early diagnosis and treatment are particularly important .This study investigated the clinical ef-fectiveness of autogeneic cancellous bone transplantation in the treatment of NTPSOTT . Methods We retrospectively analyzed 21 cases of NTPSOTT treated by autogeneic cancellous bone transplantation and evaluated using the Clinical Rating System of the American Orthopedic Foot and Ankle Society ( AOFAS) , Visual Analogue Scale ( VAS) , and X-ray and CT examinations . Results The pa-tients were followed up for 12-26 months and all healed desirably , with the graft well integrated into the surrounding tissue , but no as-similation, collapse of the articular surface , or narrowing of the joint space .The last follow-up visit revealed significantly improved AOFAS score (90.55 ±6.73 vs 50.87 ±11.42, P=0.009) and VAS score (1.32 ±0.81 vs 6.43 ±1.66, P=0.027) as compared with the baseline . Conclusion Autogeneic cancellous bone transplantation is preferable for the treatment of NTPSOTT , which can effectively reduce the pain in the ankle , maintain the joint space , and protect the function of the ankle .

Objective To analyze differences in gene expression profile of pituitary tissue in cervical spondylosis of vertebral artery type(CSA)model rats and explore the mechanism of adrenal gland's regulation of CSA.Methods Ten SPF male Wistar rats were randomly divided into model group and blank group.The CSA model was established by compound modeling method.The total RNA was extracted from the pituitary;the gene expression profile was detected by whole gene chip,ontology(GO),and signal pathway analysis.Results Compared with the normal group,the differential genes'expression profile analysis showed that the total number of the differential genes was 321(fold change︱ ＞ 2,P＜0.05),with 203 up-regulated genes and 118 down-regulated genes.A total of 1 294 genes rich in GO function were involved in the regulation of intercellular signal activity and nerve cell function;the stress response to external stimuli;and the regulation of coagulation function,angiogenesis, endometrial system,and cell cycle;There were 145 signal transducers,including adipocytokine signaling pathway, TGF-β signal transduction,AMPK signaling pathway,PPAR signal pathway,Wnt signaling pathway,and MAPK signal transduction pathway.Conclusion The pituitary regulates CSA mainly through the inflammatory stimulation,immune regulation,regulation of vertebral artery function,and endometrial system.

OBJECTIVETo investigate the growth activity of osteoblast on a novel strontium incorporated calcium sulfate and make comparison with normal calcium sulfate material.

METHODSOsteoblast was inoculated on samples and cell proliferation was measured on the 1st, 3rd, 5th days, and the activities of ALP and osteocalcin were observed on the 5th day. And microcosmic morphology of osteoblast was observed by scanning electron microscopy(SEM).

RESULTSOsteoblast grows robustly on tested material. Cell quantity on the surface of novel material was obviously higher than normal calcium sulfate material (P < 0.05). The activity of ALP and osteocalcin on novel material was 57.8% and 40.2% higher than on normal calcium sulfate material respectively (P < 0.05). On strontium incorporated surface, osteoblast spread well. Cells were polygonal with abundant cytoplasm and the morphology was active.

CONCLUSIONStrontium incorporated calcium sulfate can sustain robust growth activity of osteoblast, which is promising to be used for bone substitute materials.

3T3 Cells ; Alkaline Phosphatase ; metabolism ; Animals ; Bone Substitutes ; chemistry ; pharmacology ; Calcium Sulfate ; chemistry ; pharmacology ; Cell Proliferation ; drug effects ; Mice ; Osteoblasts ; cytology ; drug effects ; metabolism ; Osteocalcin ; metabolism ; Strontium ; chemistry

Objective To evaluated the security of endoscopic retrograde cholangiopancreatography (ERCP) among the patients aged over 80 years. Methods 80 patients who were accepted ERCP and aged over 80 years were analgzed, to learn the diseases of patients and evaluate what the impact of ERCP. To complete ERCP in the shortest time, we observed of vital signs, abdominal symptoms and nasal biliary drainage rigorouly after the opration , and to test blood routine, serum amylase, urine amylase and biochemical indicators, detect whether secondary or aggravate other organs damage within 1 week. Results There were 11 cases (13.75%) had secondary organs damage, the percentage of with over two diseases is 51.25%, 78 cases (96.25%) accepted the ERCP, the primary success rate of lithotomy in 55 cases of common bile duct stones is 74.55%, among them there were 3 cases accepted internal drainage by cutting the nasobiliary since they can not be conducted lithotomy once more. One patient of pancreatic carcinoma complicated with duodenal stenosis was treated in implantation of biliary metal stent after accepted the dilation of bile duct , and then the stent was implanted in the narrow duodenum. One patient was died of heart failure, renal failure and respiratory failure after one week; There were no other serious complications occurred, the total incidence rate of complication was 7.50%, the average operation time was (26.64 ± 8.31) min. Conclusions The patients over 80 years old are relatively safe for ERCP, the effect is obviously, and appropriate management of perioperative can reduce the incidence of complications.

OBJECTIVETo investigate the association between CTLA-4 gene polymorphism and Henoch-Schönlein purpura (HSP) in children.

METHODSSixty children who were diagnosed with HSP were enrolled as the case group, consisting of 33 males and 27 females. Thirty healthy children were enrolled as the control group. The patients were further divided into HSP nephritis (HSPN) and non-HSPN groups (n=30 each) according to the presence or absence of nephritis. Polymerase chain reaction-restriction fragment length polymorphism was used to analyze the genotype and allele frequencies at +49 and -1722 loci.

RESULTSAA, AG, and GG genotypes were detected at +49; neither genotype nor allele frequencies showed significant differences between the case and control groups, between the HSPN and non-HSPN groups, and between male and female patients (P>0.05). TT, TC, and CC genotypes were detected at -1722; neither genotype nor allele frequencies showed significant differences between the case and control groups and between male and female patients (P>0.05). There were significant differences in CC genotype frequency and T and C allele frequencies between the HSPN and non-HSPN groups (P<0.05). Combinational analysis of +49 A/G and -1722 T/C showed no significant differences in the genotype frequency between the case and control groups and between male and female patients (P>0.05). GG-CC combination showed a significant difference between the HSPN and non-HSPN groups (P<0.05).

CONCLUSIONSCTLA-4 +49 A/G polymorphism is not associated with HSP. CC genotype and C allele of CTLA-4 -1722 and the combination of GG at +49 A/G and CC at -1722 T/C may be risk factors for HSPN.

CTLA-4 Antigen ; genetics ; Child ; Child, Preschool ; Female ; Genotype ; Humans ; Male ; Polymorphism, Genetic ; Purpura, Schoenlein-Henoch ; genetics

OBJECTIVETo design and construct the plasmids expressing short hairpin RNA (shRNA) targeting human xylosyltransferase- I (XT- I) which is the initiating enzyme in the biosynthesis of proteoglycans (PC).

METHODSShort chain oligonucleotides were designed according to the sequence of XT-I provided by GenBank. The DNA segments were gained through annealing after chemosynthesis, and were cloned into Pgenesil-1 vector. The recombinant XT- I shRNA expression vectors were identified by digestion and sequencing analysis. At last the constructed XT-I expression vectors were transfected into salivary adenoid cystic carcinoma cell line (ACC-M) by Lipofectomine 2000. The expression of green fluorescent protein (GFP) was detected by inverted fluorescent microscope and the rates of transfection were detected by flow cytometer. Semiquantitative RT-PCR was used to detect the expression of mRNA level of XT- I in transfected ACC-M cells and the protein expression of XT- I was detected by Western blot.

RESULTSThe plasmids expressing shRNA targeting XT-I gene are called WJ1, WJ2, WJ3, WJ4, WJ5 and WJ6. Successful constructions were identified by digestion and sequencing. The mean rate of transfection was 50.26%. ACC-M cells transfected with WJ1-WJ6 expressed GFP successfully. And by RT-PCR and Western blot, WJ3 showed the most powerful RNAi gene silencing of inhibitory. The inhibition rate was 72.39% of mRNA level and 70.18% of protein level respectively.

CONCLUSIONThe XT-I shRNA expression vectors were constructed successfully which lays the foundation for RNAi study on the biosynthesis of PG in salivary gland tumors.

Carcinoma, Adenoid Cystic ; Cell Line ; Genetic Vectors ; Green Fluorescent Proteins ; Humans ; Pentosyltransferases ; Plasmids ; RNA Interference ; RNA, Messenger ; RNA, Small Interfering ; Salivary Gland Neoplasms ; Transfection

Objective Tio Analyze the changes of gene expression profile of adrenal tissue in cervical spondylosis of vretebral artery type (CSA) of model rats and exploring the mechanism of adrenal gland control on CSA.Methods Wistar rats were randomly divided into model group and normal group.The CSA model was established by composite modeling method.The total RNA was extracted from the adrenal gland after the model was successfully obtained.The gene expression profile was detected by whole gene chip,Gene Ontology (GO),Kyoto Encyclopedia of Genes and Genomes(KEGG) signal pathway analysis.Results Compared with the normal group,the difference gene expression profile analysis showed that the total number of differential genes was 367 (| fold change [＞ 2,P ＜0.05),among which 236 were up-regulated and 131 were down-regulated.The enrichment of gene GO functions a total of 2843,involving the regulation of cell cycle,the regulation of stress stimulation,the regulation of fibroblast proliferation,the regulation of endothelial cell proliferation,etc.Participating in the regulation of signaling pathways about 135,including mitogen-activated protein kinase (MAPK) signal transduction pathway,phosphatidylinositol 3 kinase/protein kinase B (PI3 K/Akt) signal path,Hedgehog signal path,Wingless and Int(Wnt) signal pathway and so on.Conclusion The regulation of CSA on adrenal gland is mainly to regulate the proliferation and migration of vascular endothelial cells and vascular smooth muscle cells,adhesion molecules,fibroblasts,and the stress response to stimulation.