BACKGROUND: One of the basic functions of bone is its adaptation to mechanical loading environment. Bone cells are the mechanosensitive cells in bone tissue. However, the mechanisms by which mechanical signals are transduced to chemical signals that influence bone growth and metabolism remain unidentified.OBJECTIVE: To understand the mechanotransduction pathways in osteoblasts and osteocytes, and to provide a theoretical basis for further study. METHODS: PubMed database was retrieved by computer with key words of osteoblast, osteocyte, bone cells, mechanical stress. According to inclusion criteria, 69 articles were included to summarize the transduction of mechanical signals of bone cells. RESULTS AND CONCLUSION: One of the basic functions of bone is its adaptation to mechanical loading environment. Bone cells are mechanosensitive cells. However, how the transduction of mechanical signals of cells realizes and how regulates skeleton remain poorly understood. Studies confirmed that due to the construction features and cell location of skeleton, osteoblasts and osteocytes are the most important mechanosensitive cells in bone tissue. The process of mechanotransduction can be divided into four distinct steps: ① mechanocoupling; ② biochemical coupling; ③ signal transmission; ④ effector response of bone cells. Through these four steps, the loads acting on the bones are transduced into biochemical signals, and then change the function of bone cells, finally induce the changes of bone structures to adapt the mechanical environment. The regulatory mechanisms of mechanical signals in bone marrow mesenchymal stem cells require further investigation.

Osteoblasts are the most important mechanoreceptive and osteogenic cells.The loss of bone in microgravity is mainly due to the dysfunction of osteoblasts.Research on osteoblast cytology under simulated weightlessness has made great progress in recent years.Current experiments are focusing on the changes in the cellular proliferation,differentiation,apoptosis, function and signal transduction in osteoblasts.This paper reviews the progress of the studies in this field.

Animals ; Antioxidants ; therapeutic use ; Coronary Disease ; drug therapy ; Drugs, Chinese Herbal ; therapeutic use ; Free Radical Scavengers ; therapeutic use ; Humans ; Pancreatitis ; drug therapy ; Phytotherapy ; Salvia miltiorrhiza ; chemistry

Ginseng is a typical adaptogen which has resistance to various stresses. This effect is related to the hypothalamic-pituitary-adrenal (HPA) axis. As the main active ingredients, saponin has the similar structure to steroids. The regulation characteristics of ginseng saponin on the HPA axis are narrated from the aspects of total saponin and saponin monomers in this paper after the introduction of adaptation definition and HPA axis regulation mechanisms. Pharmacological effects of ginseng saponin and the regulation effect of HPA axis are summarized finally.
Adaptation, Physiological ; Adrenocorticotropic Hormone ; secretion ; Animals ; Corticosterone ; secretion ; Ginsenosides ; isolation & purification ; pharmacology ; Humans ; Hypothalamo-Hypophyseal System ; drug effects ; secretion ; Panax ; chemistry ; Pituitary-Adrenal System ; drug effects ; secretion

Objective: To investigate the effect of paeonol (Pae) on the proliferation of human ovarian cancer cell line A2780s in vitro. Methods: Inhibitory effects of Pae with different concentrations on A2780s cells were detected by MTT assay. The cell cycle distribution and the apoptosis rate of A2780s cells were determined by flow cytometry (FCM). Results: The proliferation of A2780s cells was significantly inhibited after treatment with Pae (7.81-250.00 mg/L) in a concentration- and time-dependent manner. FCM results showed that the proportion of cells in S phase was increased while which in G0/G1 phase and G2/M phase were decreased after treatment with Pae (31.25-250.00 mg/L) for 48 h. The apoptosis rate of A2780s cells induced by Pae was increased in a concentration-dependent manner. Conclusion: Pae can inhibit the proliferation and induce the apoptosis of human ovarian cancer cells.

Objective To evaluate peak rotation in the endocardium(endo)and epicardium(epi)and peak mural torsion in patients with anterior wall acute myocardial infarction(AMI)before and after revascularization by speckle tracking imaging(STI).Methods The study comprised 20 normal controls and 21 consecutive xpatients with a first-episode anterior wall AMI with stenosis of the left anterior descending artery.All patients underwent Successful percutaneous coronary intervention within 12h onset of AMI.During one month, two patients were ruled OUt because one died of heart failure and the other suffered from persistent atrial fibrillation.Conventional echocardiography and STI were performed in normal controls and AMI patients before and one month after revascularization.Results In the left ventricle(LV)apical and basal level,peak endo-and epi-rotation and peak mural torsion in AMI patients were significantly reduced relative to those of normal control group(all P<0.01).One month after revascularization,there were significant changes in these three variables,especially in peak endorotation(P<0.01).Peak apical endo-rotation positively correlated with LV ejection fraction(LVEF)(r=0.717,P<0.01)and inversely correlated with LV end-diastolic volume(EDV)(r=-0.694,P<0.05).However,tight relations were not found among other variables at the two planes.Conclusions Peak endo-and epi-rotation and peak mural torsion can make the sensitive assessment of abnormal myocardial contractile performancein AMI patients using STI.

BACKGROUND: The role of mechanical stress in the functional regulation of osteoblasts becomes an emphasis in osseous biomechanical researches recently. There are few reports on whether fluid shear stress can induce the expression of core-binding factor α1 (Cbfα1) or not and what is its rule.OBJECTIVE: To investigate the effects of fluid shear stress (FSS) on the gene expression of Cbfα1 in human osteosarcoma cells.DESIGN: A controlled observation experiment.SETTING: Department of Aerospace Biodynamics, Faculty of Aerospace Medicine, Fourth Military Medical University of Chinese PLA.MATERIALS: Subjects were human osteosarcoma cells (MG-63) METHODS: This study was carried out at the Department of Aerospace Biodynamics, Faculty of Aerospace Medicine, Fourth Military Medical University of Chinese PLA from November 2004 to April 2005. ①After cultured for 60 hours, MG-63 were treated with 0.5 Pa (0.5 Pa stress treated group ) or 1.5 Pa (1.5 Pa stress treated group ) FSS in a flow chamber for 15, 30, 60minutes, respectively. Cover glass was put in the Petri dish containing culture medium at the same time, serving as the control group of FSS treated group. ②The total RNA in cells was isolated. Reverse transcription polymerase chain reaction analysis was made to examine the gene expression of Cbfα1 mRNA. The ratio of Cbfα1 mRNA and GAPDH mRNA was calculated.MAIN OUTCOME MEASURES: The mRNA expressions of Cbfα1 at different FSS and different time.RESULTS: ① Compared with control group, Cbfα1 mRNA expression increased significantly at 30 and 60 minutes with the treatment of FSS.Within certain time range (15 to 60 minutes), Cbfα1 mRNA expression was strengthened with the elongation of time and the increase of stress level. ②The Cbfα1 mRNA expression at 30 and 60 minutes were significantly increased in 1.5 Pa stress treated group in comparison with 0.5 Pa stress treated group (P＜0.01).CONCLUSION: FSS can significantly increase the gene expression of Cbfα1 in human osteosarcoma cells.

BACKGROUND: The mRNA expression of α1 chain of type I collagen (COL- Iα1)in rat osteosarcoma (ROS17/2.8) induced by bone morphogenetic protein-2(BMP-2)was reduced under simulated weightlessness. The protein kinase MEK1 in the signal pathway of mitogen-activated protein kinase (MAPK) plays an important role in the expression of COL- I αl mRNA regulated by BMP-2. But there was no report on the kinase activity of MEK1 under simulated weightlessness.OBJECTIVE: To investigate the effects of simulated weightlessness on the activity of MEK1 induced by BMP-2 in ROS17/2.8 cells.DESIGN: A non-randomly control study was conducted.SETTING: Department of Aerospace Biodynamics, Fourth Military Medical University of Chinese PLAMATERIALS: Rat osteosarcoma osteoblast-like cell METHODS: This experiment was conducted at the Laboratory of Aerospace cells and Molecular Biology Laboratory , Institute of Space Medico-Engineering between August 2002 and January 2003. ROS17/2.8 cells were cultured in 1 G control and rotating clinostat simulated weightlessness for 24 hours, 48 hours and 72 hours. The cells were divided into 7 groups as follows: Group 1 was blank control group in which ROS17/2.8 cells were cultured in 1 G condition without BMP2; Group 2, cells were cultured in 1 G for 24 hours;Group 3,in weightlessness for 24 hours; Group 4, in 1 G for 48 hours; Group 5, in weightlessness for 48 hours;Group 6,in 1 G for 72 hours;Group 7,in weightlessness for 72 hours. Cells in Group 2 to Group 7 were all cultured with BMP-2. BMP-2 (500 mg/L) was added into the medium 1 hou before the culture ended. Then the total protein of cells was extracted and the kinase activity of MEK1 was detected by means of Western Blotting.MAIN OUTCOME MEASURES: The content of total ERK1/2 and phosphated-ERK1/2 (p-ERK1/2) protein in the cells RESULTS: ①Total ERK1/2 expression induced by BMP-2 in ROS17/2.8 cells under simulated weightlessness: The total ERK1/2 expression induced by BMP-2 in cells in all the groups showed no significant differences ② Phosphated-ERK1/2 expression induced by BMP-2 in ROS17/2.8 .cells under simulated weightlessness: There was little protein of p-ERK1/2 in ROS17/2.8 cells in Group 1 cultured without BMP-2 in 1 G for 24 hours. The content of p-ERK1/2 in ROS17/2.8 cells in Group 2 cultured with BMP-2 in 1 G for 24 hours was much more than that in Group 1 (P ＜ 0.01). The level of p-ERK1/2 was much lower in simulated weightlessness groups than that in 1 G control groups at the same time point. In other words, the content of p-ERK1/2 in Groups 3, 5 and 7 was respectively lower than that in Groups 2, 4 and 6 (P ＜ 0.01).The expression of p-ERK1/2 showed-a tendency of gradually decreasing in Groups 3, 5 and 7 with the prolongation of time of simulated weightlessness(P ＜ 0.01 ).CONCLUSION: The kinase activity of MEK1 in MAPK signal pathway induced by BMP-2 is reduced under simulated weightlessness.

0.05).3.Thirty-three point three percent of animals from parental strain group were found fibrillations potentials and the po-sitive sharp waves in gastrocnemius electromyogram,no obvious abnormal waves were found in animals from both waaF mutant and control group.Conclusions The ganglioside-like epitope in LOS of CJ is critical antigen in inducing GM1-IgG antibody and in inducing conduction block of peripheral nerve,therefore,provide a support for the molecular mimicry theory as a pathogenesis in the axonal GBS following CJ infection.

Objective To evaluate the expression of interleukin-6 (IL-6) on peripheral blood and adenoid in children with chronic rhinosinusitis (CRS) and adenoidal hypertrophy ,to investigate the mechanism of IL-6 on the occurrence and development of CRS .Methods A total of 216 cases of hypertrophic adenoids were collected ,including 95 CRS children with hypertrophic adenoid (CRS group) ,70 children with allergic rhinitis and hypertrophic adenoid (AR group)and 51 children with hypertrophic adenoid (control group) .The plasma IL-6 concentrations were detected by ELISA ,and the expression and distribution of IL-6 in adenoid tissue was detected by immunohistochemistry .Results The plasma IL-6 level in CRS group was (49 .8 ± 8 .3)pg/mL ,significantly higher than that of in control group (33 .6 ± 6 .9)pg/mL and in AR group (35 .9 ± 5 .6)pg/mL ,differences had statistic significance ( P< 0 .05) .However ,there was no statistically significant difference between AR group and control group .Meanwhile ,the presence of IL-6 in adenoid tissue was mainly seen in inflammation cells and fibroblasts while less in mesenchymal cells ,there were statistical differences between CRS group and control group/AR group (P< 0 .05) ,but no statistical difference between AP group and control group(P> 0 .05) .Conclusion Among children with CRS ,expression of IL-6 whether in peri-plasma or in focal tissue was higher than those without CRS ,demonstrating that IL-6 may play an important role in the pathogenesis and developemnt of CRS in chil-dren .