mazEF, which is a toxin-antitoxin system located in bacterial chromosome, can mediate programmed cell death induced by various stressful conditions. In this review, the genetic structure, physiological and biochemical function of mazEF system were outlined, cellular signals and the regulation of cell factors involved in the process of cell death were introduced, and the controversy on the theory of mazEF-mediated programmed cell death was discussed. Based on the present results, It is pointed out that some questions about bacterial programmed cell death should be taken into more consideration.

In the Jinsong district of Beijing,345 patients with dyslipidemia were selected for study.Health management was implemented for one year,during which time,monitoring,analysis,and evaluation of the health of individuals and groups was conducted; health advice and guidance were given with regard to health risk factors.After the one-year intervention,the average daily dietary intake of salt,oil,and meat was reduced by 2,4,and 18 g,respectively,and the average daily intake of vegetables increased by 45 g.The average levels of body mass index,systolic blood pressure,diastolic blood pressure,total cholesterol,triglycerides,and low-density lipoprotein cholesterol were reduced by 0.47 kg/m2,3.0 mm Hg ( 1 mm Hg =0.133 kPa),1.6 mm Hg,0.76 mmol/L,0.83 mmol/L,and 0.42 mmol/L,respectively,while the average level of high-density lipoprotein cholesterol increased by 0.05 mmol/L.All the differences were significant.

Objective To investigate comparability between Sysmex different hematology analyzers.The consistency of all he-matology analyzers with the same fresh sample.Methods Selected Sysmex XE-2100 as reference instrument which attend external quality assessment.Fresh high,medium and low blood were detected in Sysmex XS-800i,Sysmex XT-4000i and Sys-mex XT-1800i,compared results of WBC,RBC,HGB,HCT,MCV and PLT.Results The bias of XS-800i and XE-2100 was WBC 2.85%,RBC 1.44%,HGB 0.75%,HCT 2.11% and PLT 5.53%.The bias of XT-4000i and XE-2100 was WBC 1.26%,RBC 0.95%,HGB 0.68%,HCT 1.35% and PLT 2.68%.The bias of XT-1800i and XE-2100 was WBC 5.21%, RBC 1.96%,HGB 1.60%,HCT 1.96% and PLT 4.95%.It had good compatability.All various parameters was in the al-lowed range.Conclusion Should maintenance and compare the hematology analyzers periodically,found the problem then calibration instruments in time,ensure the consistency of measurement results between different instruments and guarantee accuracy of the results.

Objective: To analyse correlation of bispectral index,spectral edge frequency of electroencephalogram with midazolam-induced sedation. Method: 30ASA grade Ⅰ-Ⅱ adult patients, undergoing elective surgery under regional anesthesia were randomly devided into three groups according to intravenous bolus doses of midazolam,i, e. group Ⅰ:0.05mg?kg~(-1),group Ⅱ:0.1mg?kg~(-1),group Ⅲ:0.2mg?kg~(-1). After an intravenous bolus dose of mida zolam was administered,both bispectral index (BIS), 95% spectral edge freguency (SEF) of electroencephalogram were monitored and their correlation with midazolam induced sedation was analysed. Result: Both BIS and 95% SEF-correlated with midazolam-induced sedation significantly (r= 0.86,0.73, P

Background It is widely appreciated that many animal cells rely on the mechanism of regulatory volume decrease (RVD) after swell under the hypotonic environment,which involved in some processes of cellular physiology.But the RVD of lens epithelial cells(LECs) still is being further researched.Objective Present study was to clarify the possible mechanisms and influencing factors in the RVD of LECs.Methods Human LECs line (HLE B-3)were cultured and passaged in DMEM/F12 containing 10％ fetal bovine serum(FBS),and before volume measurement,cells were stuck to the base of a perfusion chamber,Ringer solution osmolality was decreased from 15％Hypo to 45％ Hypo,and the cells stimulated by 45％ Hypo Ringer solution were used as the control group.Some experiments were performed in the presence of high extracellular K+ concentration,chloride or potassium channel inhibitor,experiments were also carried out in the nominal absence of Ca2+,Cl-or HCO-3 to test the effect of a decrease in intracellular concentration of these ions on the cell volume response.The volume changes of living cells were measured by lag-time microphotograph acquisition and analysis system (IPP6.0).Results Time course of cell volume change after hypotonic shock in HLE B-3 cells was observed.The cell swelling was followed by a gradual volume recovery,indicating the presence of RVD was influenced by the hypotonic stress.Under the stimulation of 45 ％Hypo Ringer solution,the rates of RVD were (59.1 ±7.8)％.RVD was correlated positively to the maximum cell volume (r =0.99,P＜0.05)in S shape,and RVD changes were sensitive to alter maximum cell volume in the range of 115％-135％.RVD reduced to (16.5 ± 1.6) ％,(14.7 ± 2.3) ％,respectively after acted by potassium channel inhibitor,TEA(10 mmol/L)and BaCl2(5 mmol/L)as well as chloride channel inhibitor,NPPB(100 μmol/L)and DIDS(100 μmol/L),with significant differences in comparison with the control group(all P＜0.01).RVD decreased by(5.8±1.6)％ and(2.7±0.8)％ in high concentration of K+ in extracellular fluid and the absence of Cl-(P＜0.01).RVD was significantly inhibited under the absence of Ca2+.When the 45％ Ringer solution was pH6.8,the process of RVD delayed.The rate of RVD in the first ten minutes was (0.86±0.24)％/min,showing a significant decline in comparison with (3.24±0.84) ％ / min of pH 7.4 (P ＜0.05).Conclusions HLE B-3 have RVD ability under the hypotonic stress stimulation.A certain intracellular Ca2+ concentration is the premise of RVD activation,and Cl efflux and K+ efflux are the key mechanism of RVD of HLE B-3.Acidic environment of hypotonic solution delays the occurrence of RVD.

BACKGROUND: Carotid-femoral pulse wave velocity in hemodialysis patients is influenced by multiple factors.OBJECTIVE: To explore the carotid-femoral pulse wave velocity (PWVcf) changes and related factors in maintenance hemodialysis (MHD) patients.DESIGN, TIME AND SETTING: Non-randomized control experiment was performed at the Third Hospital of Peking University from January to August 2006.PARTICIPANTS: A total of 66 MHD patients were selected from Third Hospital of Peking University.METHODS: General clinical conditions, biochemical indexes, PWVcf and subjective nutritional state were evaluated. MHD patients were divided into two groups according to the state of nutrition evaluated with SGA: non-malnutrition (n=49), malnutrition group (n=17). The PWVcf of two groups was compared, and one-way and multiple regression analyses were performed to explore PWVcf-relatest factors.MAIN OUTCOME MEASURES: PWVcf, blood albumin and parathyroid hormone.RESULTS: PWVcf was significantly positively correlated with age (r= 0.284, P< 0.05), systolic blood pressure (r= 0.468, P<0. 001), and pulse pressure (r=0.451, P< 0.001), while negatively correlated with prealbumin (r=0.318, P< 0. 05),plasma-albumin (r=0.263, P< 0.05), parathyroid hormone (r=0.167, P< 0.05), serum creatinine (r=0.347, P= 0.004)and transferring (r=0.284, P < 0.05) before dialysis. Multiple regression analysis demonstrated that pulse pressure and parathyroid hormone were independently related with PWVcf. The PWVcf was significantly increased in malnutrition group compared with non-malnutrition group (P < 0.05). CONCLUSION: Pulse pressure is the major clinical determinants of arterial stiffness in patients with MHD independent of conventional risk factors for cardiovascular disease; Malnutrition and atherosclerosis are common complications of MHD,showing close relationship. The PWVcf was significantly increased in malnutrition patients.

Warfarin is a well-accepted drug used for preventing thromboembolic diseases. It is important to monitor the dosage of warfarin. Prothrombin time is one of the screening tests of extrinsic coagulation path,which is the first choice to monitor the oral use of warfarin. Standardized prothrombin time, namely international normalized ratio ( INR ) is used to adjust warfarin dosage in clinical practice. Many herbal medicines and foods may enhance the effect of warfarin therapy,and some of them may weaken this effect,which can result in severe clinical complications.

BACKGROUND:Although the traditional surgical treatment can improve the symptoms of patients with senile osteoporotic vertebral fracture, the treatment easily produces bone graft fusion failure and pseudoarticulation formation and affects clinical effects. OBJECTIVE:To investigate biomechanical properties of anterior cervical pedicle screw and the effects on osteoporotic vertebral stability. METHODS:A total of 16 fresh cadaver cervical specimens contained 64 motion segments (C3-4, C4-5, C5-6 and C6-7). The 64 segments by the way of implantation were randomly divided into ordinary anterior locking screw fixation group and lower anterior vertebral pedicle screw system group (32 segments per group). The mechanical properties were determined on the biomechanical testing machine for each group. RESULTS AND CONCLUSION:(1) Biomechanics:Compared with the ordinary anterior locking screw fixation group, the maximum pul-out strength, screw path length, postoperative vertebral column height, the maximum surface strain, strain maximum and the range of maximum values were increased in the lower anterior vertebral pedicle screw system group (P<0.05). (2) Results suggest that compared with the ordinary anterior locking screw fixation group, lower cervical anterior pedicle screw required larger extraction force and was more stable for osteoporotic vertebrae.

BACKGROUND:From the point of view of human anatomy, the load of the spine is more. When the body moves, the range of activities, and activity are relatively large. After screws were implanted in the spine, if biomechanical properties and stability are not up to the standard, it easily leads to lack of grip force of screw and screw loosening so as to increase the incidence of complications after treatment.
OBJECTIVE:To compare biomechanical properties and stability of the spine after insertion of pedicle screw and cervical vertebral screw into the spine.
METHODS:100 vertebrae under human cervical spine specimens were analyzed and randomly divided into cervical vertebral screw fixation group and pedicle screw fixation group. Cervical vertebral screws and pedicle screws were implanted in lower cervical spine specimens. Electro Force 3510 material testing machine was used to test axial pul-out force, axial pul-out strength after the fatigue loading, and fixed stability. The biomechanical properties and stability were compared after two kinds of screws were implanted in the spine.
RESULTS AND CONCLUSION:(1) Instantaneous pul out force and immediate pul out stiffness were significantly higher in the pedicle screw fixation group than in the cervical vertebral screw fixation group (P<0.05). (2) Fatigue pul-out strength and fatigue pul-out stiffness did not have significant differences in both groups, but statistical analysis showed significant differences (P<0.05). Fatigue pul-out strength and fatigue pul-out stiffness were significantly higher in the pedicle screw fixation group than in the cervical vertebral screw fixation group. (3) These results suggested that pedicle screw fixation after implantation in the spine provides sufficient fixation stability, has better fatigue resistance, elevates instantaneous pul-out force and fatigue pul-out strength, and presents strong stability.

BACKGROUND:Silk fibroin, as an inorganic mineralization template, can induce hydroxyapatite crystal growth, and combined with nano-hydroxyapatite can simulate the inorganic and organic components of natural bone, which is expected to become the most ideal bone graft material. OBJECTIVE:To prepare the silk fibroin/nano-hydroxyapatite composite material and investigate its treatment outcomes in spinal fusion. METHODS:Silk fibroin/nano-hydroxyapatite composite was synthesized by the co precipitation method with silk fibroin and calcium phosphate as raw materials, to simulate the structure and composition of the bone tissue. The crystal phase composition and microstructure of the composite scaffold were analyzed by X-ray diffraction and transmission electron microscope. Osteoblasts were seeded onto the composite, and the cel adhesion and proliferation were observed under inverted microscope. The lumbar posterolateral spinal fusion models were established in the New Zealand rabbits, fol owed by treated with autologous bone graft (control group) and composite (composite group), respectively. The gross, radiological and histological observations of bone fusion were compared between groups. RESULTS AND CONCLUSION:Silk fibroin/nano-hydroxyapatite composite appeared to be fascicular under electron microscope, the length was 200-500 nm and width was 20-30 nm. And the hydroxyapatite was about 200 nm in length and 50 nm in width. X-ray diffraction showed that the bottom of diffraction peak was wide, and the peak was not sharp. Transmission electron microscope found that cel s adhered wel onto the composite scaffold at 2 days. Scanning electron microscope showed that the polygonal, oval or conical cel s covered most of the composite scaffold holes, presented obvious mitotic phase at 5 days. The third generation of MC3T3-E cel s tended to rise at first 3 days, and then decreased. The fusion site of L5-6 transverse process was strong, and non-bony fusion occurred. At the same time, numerous new bones were visible in the composite group. Hematoxylin-eosin staining showed a large number of cel aggregation, abundant osteoblasts surrounding cartilage, and the bone tissues were in a regular arrangement in the composite group. Moreover, irregular trabecular bone with medul ary cavity was found in the composite material. These results suggest that the silk fibroin/nano-hydroxyapatite composite with the similar structure and composition of natural bone can achieve satisfactory fusion effect in the rabbit lumbar posterolateral fusion.