Objective： To study the role of mechanical stress on osteoblast-like characteristics expressed by human periodontal ligament cells in vitro. Methods： Human periodontal ligament cells (hPDLC) were cultured by explant method. We investigated the gene expression for osteoblast-like marker proteins in periodontal ligament stimulated by cyclical mechanical force in vitro by in situ hybridization with non-radioisotopic oligonucleotide probe for alkline phosphatase (ALP) and osteocalcin (OCN). Results： Human periodontal ligament cells exhibited a stronger signal for ALP mRNA stimulated by cyclical mechanical force, and exhibited a moderately intense positive signal for OCN mRNA—OCN was a marker of differentiated osteoblast-like cells. Conclusion： These findings suggest that mechanical force plays role in differentiation from hPDLC to osteoblast-like cells.

Objective To summarize the experience of perioperative management of coronary artery bypass graft(CABG) in high-risk patients with coronary heart disease.Methods The clinical data of 164 patients underwent CABG from March 2004 to November 2005 were analyzed.Of 164 patients,151(92.05%) cases had severe coronary heart disease.Results Totally 144 artery-vessels and 353 venous-vessels were transplanted to patients.Combined operative procedures included 11 cases of ventricular aneurysm resect,5 cases of valve replacement,5 cases of valve repair,and 1 case of surgical repair of perforation of ventricular septum.Post-operative complications included 2 cases of low cardiac output,1 case of respiratory failure,1 case of renal failure,and 1 case of cerbral infarction.Two patients died and the operative mortality was 1.22%.Conclusion CABG procedure is safe in the treatment of high-risk patients with coronary heart disease.Proper preoperative and perioperative treatment can improve the curative effects significantly.

OBJECTIVETo investigate the osteoblast-like functional characteristics exhibited by human periodontal ligament cells (hPDLCs) under mechanical force.

METHODSHuman PDLCs cultured in vitro were stretched by mechanical force. Radioimmunoassay (RIA) was used to measure the expression of secreting alkaline phosphotase (ALP) and osteocalcin (OCN). The non-secreting ALP, OCN and osteopontin (OPN) in cells were determined by immunohistochemistry.

RESULTSIt exhibited increasing of ALP secreted into conditional media, and in the 24 hour period there were two peaks which appeared at the 2nd and 4th hour and the 24th hour (P < 0.01). While in the late of the 24 hours, expression of OCN in conditional media increased (P < 0.05).

CONCLUSIONMechanical force induces hPDLCs to differentiate into functional osteoblast-like cells and plays a role in bone remodeling.

Alkaline Phosphatase ; metabolism ; Cells, Cultured ; Humans ; Osteocalcin ; analysis ; Osteoclasts ; physiology ; Osteopontin ; Periodontal Ligament ; cytology ; Sialoglycoproteins ; analysis ; Stress, Mechanical

OBJECTIVETo investigate the prevalence of malocclusion in China.

METHODSBased on individual normal occlusion and Angle's classification of malocclusion, standard investigation form was made. 25,392 children of different dental ages were evaluated by orthodontic professionals.

RESULTSThe prevalence of malocclusion among Chinese children was 67.82%. The prevalence of malocclusion among children with different dental age and the proportion of the different types of malocclusions were revealed.

CONCLUSIONThe prevalence of malocclusion among Chinese children had increased from 40% to 67% over the last 40 years.

Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Male ; Malocclusion ; classification ; epidemiology ; Mass Screening ; methods ; Prevalence