BACKGROUND: The reaction of osteoblasts is important role in the reconstruction of osteocytes, and the mechanism of bone remodeling can be known from the cytological level through analyzing the mechanical reaction of osteoblasts under different loading.OBJECTIVE: To analyze the effects of low frequency vibration on the proliferation and differentiation as well as the matrix excretion of cultured human osteoblasts.DESIGN: A comparative observation.SETTING: Department of Orthopaedics, Nanfang Hospital of Southern Medical University.MATERIALS: The experiment was carried out in the laboratory of Nanfang Hospital from January to December in 2002. Human osteoblasts were isolated from the iliac cancellous bone of adults.METHODS: The osteoblasts were cultured for 48 hours, and then treated with low frequency vibration of 0.1, 0.2, 0.5, 2 and 5 Hz. The proliferation of the osteoblasts was detected with flow cytometry, and the activity of alkaline phosphatase (ALP) and content of osteocalcin were assayed by spectrophotometric methods and radioimmunoassay respectively.MAIN OUTCOME MEASURES: ① Effects of low frequency vibration on the ALP activity and osteocalcin excretion of osteoblasts; ② Effects of low frequency vibration on the proliferation of osteoblasts detected with flow cytometry.RESULTS: ① 0.2 and 0.5 Hz vibrations could markedly increase the ALP activity of osteoblast (P ＜ 0.01), but that of 5 Hz obviously decreased the ALP activity (P ＜ 0.01). 0.1 and 2 Hz vibrations had no obvious effects on the ALP activity of osteoblasts. ② 0.2 and 0.5 Hz vibration could significantly increase number of osteoblasts at S phase from 10.4% to 12.45% and 16.12%, and the proliferative index increased from 20.14% to 26.21% and 28.75%; 0.1 and 2 Hz vibration has not obvious effects in osteoblast proliferation index; 5 Hz vibration obviously decreased the proliferative index value to 13.22% (P ＜ 0.05). 0.1 and 2 Hz vibrations had no obvious effects on the proliferative index of osteoblasts (P ＞ 0.05). ③ 0.2 and 0.5 Hz vibrations could obviously increase the amount of osteocalcin excretion to 1.87 μg/L and 2.47 μg/L(P ＜ 0.05), but 2 and 5 Hz vibrations decrease the amount of osteocalcin excretion (P ＜ 0.05), and that of 0.1 Hz had no obvious effect on amount of osteocalcin excretion (P ＞ 0.05).CONCLUSION: Low frequency vibrations of 0.2-0.5 Hz could accelerate the proliferation and differentiation as well as the excretions of active materials of osteoblasts, and it plays an instructive role for low frequency vibration to treat fracture.

Objective To evaluate the killing efficacy of chlorine-releasing agents (CRAs) with different concentrations on multidrug-resistant Acinetobacter baumannii.Methods Totally 30 clinical strains of multidrug-resistant Acinetobacter baumannii were collected from November 2008 to December 2009.Killing efficacy of CRAs on these strains was evaluated by quantitative suspension test.The one-way analysis of variance was performed.Results The log values of killing to 30 strains of multidrug-resistant Acinetobacter baumannii were all ≥5.00,when the bacteria were exposed to available chlorine concentrations 400 mg/L of CRAs for 10 min,600 mg/L for 10 min,800 mg/L for 3 min and 1000 mg/L for 1 min,respectively.And effective rates were all 100％. Furthermore,there were significant differences among different available chlorine concentrations exposed for the same time ( except 10 min) ( F =72.72,64.79 and 32.33,P =0.00),and among different exposure time in the same available chlorine concentration ( except 1000 mg/L) ( F =110.42,20.41 and 3.20,P=0.00,0.00 and 0.03).Conclusion Satisfactory killing efficacy of CRAs to multidrug-resistant Acinetobacter baumannii can be achieved with available chlorine concentration 500 mg/L to 1000 mg/L and exposure time 10 min to 30 min.

Objective To study the ultrastructural changes of hypertrophic scars and animal wound healing models induced by radionuclide 90 Sr exposure and to get the most effective dosage and time in the prevention and treatment of scars. Methods The clinical hypertrophic scars and animal wound models were exposed using 90 Sr applicator in this study. The exposure doses were 200 800 cGy and 200 4 000 cGy. Then the fibroblastic ultrastructure of the tissues from the experimental and control groups were observed with transmission electron microscope. Results Compared with the control groups, capillaries and fibroblasts obviously increased in small and medium doses (200 600 cGy) groups and fibroblastic function was activated. The fibroblasts decreased and fibroblastic function was inhibited in large dose (800 2 000 cGy) groups. Conclusions Small and medium dose of 90 Sr can accelerate wound healing, and can therefore be used in the treatment of early wounds (2 3 days after wounded) ; large dose of 90 Sr can prevent scars from hyperplasia, and can be used in the wounds of the first week after operation; 1 000 2 000 cGy 90 Sr can cure the old hypertrophic scars or keloids; It is useless that 90 Sr exposes before operation for prevention of scars.The most effective method to prevent scars from hyperplasia is large dose of 90 Sr exposure after operation.

Objective To observe the effect of metoclopramide combined with early enteral nutritional on patients with mechanical ventilation after craniocerebral operation.Methods A prospective randomized control study was conducted.56 patients with mechanical ventilation after craniocerebral operation were randomly divided into metoclopramide combined with early enteral nutritional group (observation group) and parenteral nutrition group (control group),28 in each group.The patients in the observation group received early enteral nutrition (24-48 h after operation),and intramuscular injection of metoclopramide (10mg Q8H) for 7 days.The patients in the control group received parenteral nutrition.The nutritional parameters,mechanical ventilation (MV) time,success rate of the ventilator weaning and the occurrence rate of pneumonia associated with ventilation (VAP) in one week,the incidence of adverse reaction were compared between the two groups.Results After 1 week therapy,the nutritioual parameters of the two groups showed no statistical significance(P ＞ 0.05);the observation group compared with the control group,3 、7days of blood glucose(P1 、P2) decreased significantly[(8.9 ± 1.6) mmol/L vs (11.4 ± 3.2) mmol/L,(8.2 ± 1.3) mmol/L vs (10.6 ± 2.1) mmol/L] (P1 =0.002,P2 =0.011),Mechanical ventilation (MV) time (P3) and the occurrence rate of VAP(P4) in one week also declined[(6.5 ±2.3)d vs (8.9 ±3.1)d,21.4％ vs 46.4％] (P3 =0.022,P4 =0.048),but within a week of success rate of the ventilator weaning improved (67.9％ vs 39.3％,P5 =0.032).Return rate (P6),gastrointestinal bleeding (P7) was significantly lower than those of the control group (17.9％ vs 42.9％,14.3％ vs 42.9％,P6 =0.042,P7 =0.038),but abdominal distention,diarrhea were no significant contrast (P ＞ 0.05).Conclusion Metoclopramide combined with early enteral nutritional may obviously improve the nutrition parameters,shorten the MV time,decrease the occurrence rate of VAP,not increase in side effects.

OBJECTIVE To investigate the qacA/B genes in meticillin-resistant Staphylococcus aureus(MRSA) and their significance.METHODS Totally 221 MRSA strains were clinically isolated.The genes of qacA/B were analyzed using polymerase chain reaction(PCR).RESULTS From them 101 strains were found the qacA/B genes,the positive rate of qacA/B genes was 45.7%.And 71 strains were selected for qacA PCR detection,20(28.2%) were with qacA gene and 27(38.0%) were with qacA/B gene,suggesting that the seven strains be with qacB gene.CONCLUSIONS MRSA strains have emerged the high-frequency qacA/B disinfectant resistance gene.Application of chlorhexidine and other disinfectants to prevent postoperative nosocomial infections must be reassessed.The efficacy of existing disinfectants or disinfection methods should arouse our wider attention.Disinfectant resistance gene detection technology provides a practical means for the research of the disinfectant-resistant bacteria and the clinical application of the molecular epidemiology research.

OBJECTIVE To investigate the genes of AmpC and ?-lactamases and antibiotic resistance of A.baumannii strains in elderly.METHODS The sensitivity to 13 kinds antibacterials was analyzed according to CLSI 2005′s Standard.The genes of AmpC and ?-lactamases were detected by polymerase chain reaction(PCR).RESULTS Most of the strains were A.baumannii.In 20 strains of A.baumannii,the positive strains of AmpC(chromosome) were 17(85%),that of TEM and PER 5 strains were 11 strains(55%) and 25%,respectively.CONCLUSIONS High positive percentages of AmpC(chromosome),TEM and PER genes in A.baumannii strains isolated from elderly are found.

Objective To study MRI volumetric measurement of hippocampal formation using statistic parametric mapping(SPM) software and to discuss the value of the method applied to Alzheimer's disease (AD).Methods The SPM software was used to divide the three-dimensional MRI brain image into gray matter, white matter and CSF separately.The bilateral hippocampal formations in both AD group and normal control group were delineated and the volumes were measured.The SPM method was compared with conventional method based on region of interest (ROI), which was the gold standard of volume measurement The time used in measuring the volume by these two methods were respectively recorded and compared by two independent samples' t test.Moreover, 7 physicians measured the left hippocampal formation of one same control with both of the two methods.The frequency distribution and dispersion of data acquired with the two methods were evaluated using standard deviation coefficient Results (1)The volume of the bilateral hippocampal formations with SPM method was (1.88±0.07) cm~3 and (1.93±0.08) cm~3 respectively in the AD group, while was (2.99 ±0.07) cm~3 and (3.02 ±0.06) cm~3 in the control group .The volume of bilateral hippocampal formations measured by ROI method was (1.87 ±0.06) cm~3 and (1.91 ±0.09) cm~3 in the AD group, while was (2.97 ±0.08)cm~3 and (3.00 ±0.05) cm~3 in the control group.There was no significant difference between SPM method and conventional ROI method in the AD group and the control group(t=1.500, 1.617, 1.095, 1.889,P> 0.05) .However, the time used for delineation and volume measurement was significantly different.The time used in SPM measurement was (38.1 ±2.0) min, while that in ROI measurement was (55.4 ±2.4) min (t=-25.918, P<0.01).(2)The average volumes of the left hippocampal formation with the two methods measured by the 7 physicians were (2.86±0.20) and (2.76±0.52) cm~3 respectively.The frequency distribution of hippocampal formation volume measured by SPM method and ROI method was different.The CV_(SPM) was 7% and the CV_(ROI) was 19%.Conclusions The borders of hippocampus formation in brain gray matter could be conveniently delineated by SPM software.The accuracy and repetition of measurement was improved by SPM method.The shorter time used in measurement made it possible for MRI volumetric measurement of hippocampal formation to be applied in assessment of relevant neuropsychiatric diseases.

Objective To investigate the effects of nitric-oxide synthase inhibitor on matrix metalloproteinases (MMPs) expression in osteoarthritis (OA) cartilage by Luminex analysis,and to explore the mechanism of nitric-oxide synthase inhibitor on modification of the metabolism of OA cartilage.Methods Fifteen specimens of articular cartilage taken from the patients with OA were cultured and divided in two groups.The control group was those with no intervention.L-NIL group was co-cultured with NOS inhibitor L-NIL.After 72 h cultivation,the release of NO and the activity of NOS on OA cartilage were measured by Griess reaction and spectrophotometric methods.MMPs (MMP-1,MMP-2,MMP-3,MMP-9,MMP-13) expression was measured by Luminex analysis.Comparisons between groups were performed with paired sampies t test.Results After cultured for 72 h,spectrophotometric analysis showed high concentration of NO release[(216±47) μmol/L ] and high level of active NOS [(5.7±1.3)U/ml]in supernatants of the control,1 mmol/L concentration L-NIL could evidently reduce NO release [(55±20)μmol/L,P<0.01] and NOS activity [(1.7±0.7)U/ml,P<0.01 ].Luminex analysis demonstrated high MMP-1,MMP-2,MMP-3,MMP-9,MMP-13 expression in cartilages of the control group [respectively for (10.8±5.4)ng/ml,(9.2±3.3) ng/ml,[11.6±4.2 )ng/ml,(1.27±1.07)ng/ml,(3.6±1.3)ng/ml] and 1 mmol/L concentration L-NIL could evidently inhibit MMP-1,MMP-2,MMP-3,MMP-9,MMP-13 expression [respectively for (3.6±1.8)ng/ml,(2.3±1.2)ng/ml,(3.6±1.4)ng/ml,(0.65±0.21)ng/ml,(1.8+0.5)ng/ml,P<0.05 ].Conclusion Luminex analvsis has shown that NOS inhibitor can reduce NO release and NOS activity and modify metabolism of articular cartilage by inhibiting the over-expression of MMPs.

Objective To investigate ehloramphenicol,tetracycline,rifampicin and trimethoprimsulfamethoxazole resistance and the related genes in multi-drug resistant Acinetobacter baumannii(MDR-ABA).Methods Sixty-two strains of MDR-ABA were isolated from clinical samples,and their susceptibilities to 22 antimicrobial agents were detected by Kirby-Bauer disk diffusion tests.Genes related to chloramphenicol(catB and cmlA),rifampicin(arr-2/3),tetracycline(tetA and tetB)and trimethoprimsulfamethoxazole(sull,dfrA1,dfrA5,dfrA7/17,dfrA12,dfr85)resistance and drug emux genes(tehA,emrB,emrD,emrE,smr-2,mdfA)were analyzed by PCR and verified by DNA sequencing.Results Resistant rates of these MDR-ABAs to chloramphenicol,rifampicin,tetracycline and trimethoprimsulfamethoxazole were 100.0%(62/62),100.0%(62/62),90.3%(56/62)and 82.3%(51/62)respectively,while62 strains(100.0%),46 strains(74.2%),36 strains(58.1%)and 8 strains (12.9%)were detected to carry mafA,tetB,sull and tehA genes,respectively.The lest 13 genes were all negative.tetB,sull,tehA and mafa genes(2 for each)chosen optionally from positive ones were verified by DNA sequencing and BLASTn.and all were identified as the same sequences in GenBank.Conclusions MDR-ABAs show hish resistance to chloramphenicol,tetracycline, rifampiein and trimethoprimsulfamethoxazole.Multi-drug resistant phenotypes of MDR-ABAs may be closely related to mdfA genes harboring in strains.

Objective To analyze molecular evolution of carbapenemase KPC-12 and its binding free energies with β-lactams.Methods Class A beta-lactamases were divided into 2 clusters:those with carbapenemase activities and those without.Minimum Evolution method in MEGA4.1 software was used to analyze molecular evolution of class A beta-lactamases with carbapenemase activity,including KPC-2 to KPC-13,SFC-1,SME-1,IMI-1,NMC-A,and class A beta-lactamases without carbapenemase activity,including TEM-1,SHV-1.Then,tertiary structure of KPC-12 was predicted by homology modeling as reported in SWISS-MODEL database depending on tertiary structure of KPC-2.Moreover,DOCK module in ArgusLab 4.1 software was used to perform molecular docking of KPC-12 to 10 kinds of beta-lactams substrates,and the binding free energies (△ G) were calculated.Results Molecular evolution between KPC-12 and KPC-2 was the closest.The top three decline in binding free energies of β-lactams were penicillin G sodium salt (△G =-8.45149 kcal/mol),ertapenem (△G =-8.36383 kcal/mol) and ampicillin (△G =-8.19326 kcal/mol),while the last two decline in binding free energies of β-lactams were aztreonam (△G =-6.50614 kca]/mol) and clavulanic acid (△G =-6.88533 kcal/mol).Conclusion Carbapenemase KPC-12 has high catalytic activities to penicillin G sodium salt,ertapenem and ampicillin,while has low catalytic activities to aztreonam and clavulanic acid.