Zebrafish was selected as model animal, and glucocorticoid dexamethasone was used as a model compound to establish a rapid and high efficient osteopenia model. Zebrafish larvae at 4 days post fertilization (dpf) were exposed to a serial concentrations of dexamethasone solutions, and 0.5% DMSO was selected as the vehicle control group. All groups were incubated in 24-well plates (28.5 degrees C) until 9 dpf. In addition, effects of 10 micromol x L(-1) dexamethasone on preventing against osteopenia induced by etidronate disodium were also investigated. Zebrafish bones at 9 dpf were stained with alizarin red. Quantitative analysis of the stained area was performed by microscopic inspection and digital imaging methods to reflect the amount of bone mineralization. Results showed that dexamethasone group at 2.5, 10 and 25 micromol x L(-1) can decrease the staining area and the staining optical density values of zebrafish head bones when compared with the vehicle control group (0.5% DMSO), which suggested that dexamethasone can significantly reduce the zebrafish mineralized bone and the bone mineral density. Results also showed that 15 and 30 microg x mL(-1) etidronate disodium can increase the mineralized matrix of zebrafish head bone and prevent against osteopenia induced by dexamethasone. In conclusion, the study indicated that zebrafish can be an idea osteopenia model induced by dexamethasone.

Prednisolone-induced zebrafish osteoporosis model was used to explore the bone-strengthening effect of Jie-Gu-Tang (JGT). Zebrafish larvae of 5 days post fertilization (d.p.f.) were co-exposed with 25 μmol·L-1 pred-nisolone and a series of JGT solutions with a range of concentrations (0.025, 0.25, 2.5, 25 and 100 mg crude herb per liter). The 25 μmol·L-1 prednisolone was selected as the model group. Etidronate disodium (15 and 30 mg·mL-1) with 25 μmol·L-1 prednisolone was used as the positive group. And 0.5% DMSO was used as the vehicle control group. All groups were incubated in 24-well plates (28.5℃) until 10 d.p.f. Zebrafish skeleton at 10 d.p.f. was anes-thetized and fixed for staining with alizarin red. Quantitative analysis of the stained area was performed by microscop-ic inspection and digital imaging methods to reflect the amount of zebrafish head skeleton mineralization. The results showed that prednisolone group at 25 μmol·L-1 concentration can obviously decrease the staining area and the stain-ing optical density values when compared with the vehicle control group (0.5% DMSO). Compared with the model group, both etidronate disodium (15 and 30 mg·mL-1) and JGT (2.5, 25 and 100 mg crude herb per liter) can in-crease the mineralized matrix and integrated optical density (IOD) of zebrafish head skeleton significantly with dose-effect relationship. It was concluded that zebrafish osteoporosis model was successfully used in the evaluation on bone loss prevention and bone formation promotion of JGT, which provided basis for the reliability and reasonability of zebrafish model.

OBJECTIVE:To study the cardiac and skeletal toxicity of retinoic acid (RA) in Danio rerio at early life stage. METHODS:Danio rerio embryos of 24 hours post fertilization(hpf)were used as toxicity model and were exposed under medium with various concentrations of RA(0.1,1,10,25,100 μmol/L). The morphology of embryos and larvae hearts were observed 24,48 h after exposed. LC50 was calculated. Danio rerio larvae of 4 days post fertilization (dpf) were used as skeletal deformity model and were exposed with a series of RA at various concentration(0.1,1,10,25,50μmol/L). They were sacrificed 5 d later, and then Danio rerio skeleton were fixed for staining with alizarin red. The microscopic was used to observe the difference of stained skeleton area. RESULTS:RA caused significant adverse effects on hatching capabilities of Danio rerio embryos,and the ob-vious malformation features were produced during the culture process. 1-100 μmol/L RA could cause heart malformation in Danio rerio embryos and larvae,and the main heart malformation characteristics included heart linearization,pericardial edema,yolksa-cedema,hemocytes accumulation incardiac region. 100 μmol/L RA could inhibit the hatching capabilities of Danio rerio embryos, and caused lethal effects on embryos and larvae. The LC50 were 36.44,23.69 μmol/L after exposed for 24,48 h. 0.1-50 μmol/L RA induced vertebral column sclerotization of Danio rerio embryos and larvae in advance,which was positively associated with the con-centration of RA. CONCLUSIONS:RA can cause cardiac and skeletal toxicity in Danio rerio embryo and larvae,which is positive-ly associated with the concentration of RA.

Objective:To explore the effect of sub-inhibitory concentration of imipenem on the bio-activities of methicillin resistant Staphylococcus aureus(MRSA) and illuminate the inhibitory effects of carbapenem antibioty on the activity of MRSA and their mechanisms,and to provide the basis for using the carbapenem antibiotics in the treatment of MRSA infection.Methods:Five ST239 type of MRSA clinical isolates were selected and were co-cultured with 1/10 and 1/2 minimal inhibitory concentration (MIC) of imipenem for 1.5,6.0 and 12.0 h,which were divided into control group(no imipenem),1/10MIC group(1/10MIC of imipenem),and 1/2MIC group(1/2MIC of imipenem).Fluorescent quantitative real-time PCR method was used to determine the relative mRNA expression levels of virulence-related genes fibronectin A(fnbA),staphylococcal protein A(spa),α-hemolysin(Hla),leukocidin D(lek-D),leukocidin E(lek-E),and enterotoxin A in various groups;Spectrophotometry was used to detect the proliferation activity of MRSA strains in various groups in vitro.Results:After co-culture for 6.0 and 12.0 h,the proliferation activities of 5 trains of MRSA in 1/2MIC group in vitro were significantly decreased compared with control group (P<0.01).The relative mRNA expression levels of 6 virulence-related genes of 5 strains of MRSA in 1/10MIC and 1/2MIC groups were significantly decreased compared with control group(P<0.01).After co-culture for 12.0 h,the mRNA expressions of all the tested virulence-related genes were not found.Conclusion:The sub-inhibitory concentration of imipenem shows obviously inhibitory effect on the mRNA expressions of multiple virulence-related genes of ST 239 type of MRSA strains,and higher concentration of imipenem can suppress the proliferation of MRSA strains in vitro.Imipenem shows the potential value in the treatment of the severe MRSA infected patients.

Model organism zebrafish was used to study metabolism of asperosaponin VI from Dipsacus asper Wall. ex Henry for the first time. Metabolic components of asperosaponin VI after exposing to zebrafish for 24 h were identified by high performance liquid chromatography--electrospray mass spectrometry (HPLC-ESI-MS), the separation was performed with a Zorbax C18 column using a binary gradient elution of 0.05% formic acetonitrile--0.05% formic acid water. The quasi-molecular ions of compounds in both negative and positive mode were observed for molecule mass information, and the potential structures were identified by attentive study on the deglycosylation metabolites and one hydroxylation metabolite of asperosaponin VI. The results were highly in consistent with metabolism of asperosaponin VI in rat. It can be concluded that zebrafish model can wonderfully imitate current metabolic model with advantages of small amount of lower cost, far less amount compound, higher efficiency and more simple, and can reflect integrated metabolism results of in vivo method. Zebrafish metabolic model may become a novel organism model for quick predication on metabolism of even mircoamount compound, which can enrich the available models greatly.

Objective To establish the method of solvent desorption gas chromatography for determination of bromoform in workplace air.Methods Bromoform in the air was adsorbed by activated carbon tube sampling and solvent desorption using carbon disulfide,then analyed by GC with DB-FFAP capillary column.Results The linear regression equation is y=1.22x-0.81 (r=0.999 9) between 0.57～300.00 μg/ml of target concentration in the air.The detection limit was 0.17 μg/ml.The relative standard deviations of the batch and inter batch were 1.7％～3.6％,2.8％～6.3％,respectively.The sampling efficiency was 100％.The overall desorption efficiency was 95.0％.The breakthrough capacity was more than 0.61 mg (100 mg activated carbon).Conclusion The method is suitable to determine bromoform in the air of workplace.

Objective To establish the method of solvent desorption gas chromatography for determination of bromoform in workplace air.Methods Bromoform in the air was adsorbed by activated carbon tube sampling and solvent desorption using carbon disulfide,then analyed by GC with DB-FFAP capillary column.Results The linear regression equation is y=1.22x-0.81 (r=0.999 9) between 0.57～300.00 μg/ml of target concentration in the air.The detection limit was 0.17 μg/ml.The relative standard deviations of the batch and inter batch were 1.7％～3.6％,2.8％～6.3％,respectively.The sampling efficiency was 100％.The overall desorption efficiency was 95.0％.The breakthrough capacity was more than 0.61 mg (100 mg activated carbon).Conclusion The method is suitable to determine bromoform in the air of workplace.

Objective To study the effects of neonatal bilateral and unilateral early sucking on the secretion time and the amount of colostrum.Methods A total of 300 cases with normal full-term delivery and nipple condition were selected and randomly divided into two groups:bilateral early sucking group and unilateral early sucking group.Women in the two groups were assisted by a midwife within 1 h after birth to implement early suction,with women of bilateral early sucking receiving breast sucking 15 minutes on each side and unilateral early sucking group 30 minutes just on one side.Maternal lactation′s initiating time and amount of lactation of two groups after postpartum 6 hours,24 hours,48 hours and 72 hours were analyzed.Results There was no difference of lactation initiating time in bilateral early sucking group and unilateral early sucking group (P >0.05).After 6 hours,lactation in the 2 groups had no difference (P >0.05).After 24 hours,48 hours and 72 hours,number of women with sufficient lactation in bilateral early sucking group was greater than unilateral early sucking group (P <0.05).Conclusions Bilateral early sucking is more favorable than unilateral early sucking postpartum for lactation amount.