ABSTRACT
@#：【Objective】To provide basic experimental basis for quantitative detection and analysis of antibiotic susceptibilityandheteroresistancein Mycobacterium tuberculosis byflowcytometry，weinvestigatedtheperformanceof propidiumiodide（PI）and6-carboxyfluoresceindiacetae（6-cFDA）inidentifyingdeadorlivingMycobacterium tubercu⁃ losis.【Methods】PIand6-cFDAwereusedtostain10strainsofpureculturedliving Mycobacterium tuberculosis suspen⁃ sion with turbidity of 1 McClell and the corresponding suspension with turbidity of 1 McClell heated at 85℃ for 30 minutes，respectively.Themeanfluorescenceintensity（MFI）wasmeasuredbyflowcytometry.TheMFIboundaryvalue fordistinguishingdeadandlivingMycobacterium tuberculosisweredeterminedaccordingtoreceiveroperatingcharacteristic （ROC）curves.Thesameexperimentswerecarriedoutwithother10strainsofliving Mycobacterium tuberculosis suspen⁃sionand10dead Mycobacterium tuberculosis suspension，andtheMFIthresholdwasusedtodeterminetheviabilityof bacteria.【Results】（1）IntheexperimentofdeterminingMFIboundaryvalue，theMFIof10strainsofdeadbacteria suspensionstainedwithPIwasnon-normaldistribution，themedianvaluewas2459，andtheMFIof10strainsofliving bacteriasuspensionstainedwithPIwasnormaldistribution，themeanvaluewas426±180.TheMFIboundaryvalueof deadbacteriastainedwithPIwas1329.TheMFIof10strainsofdeadbacteriaand10strainsoflivingbacteriasuspen⁃ sionstainedwith6-cFDAwasnormaldistribution，andthemeanvaluewas49±4and7144±4511，respectively.The MFIthresholdof6-cFDAstainingforlivingbacteriawas1021.（2）TheMFIthresholdsforidentifyingdeadbacteriaby PIstainingandtheMFIthresholdsforidentifyinglivingbacteriaby6-cFDAstainingwereusedtodetect10otherliving bacterialsuspensionsand10deadbacterialsuspensions.Theaccuracy，sensitivity，specificity，Yondeindex，positive predictivevalueandnegativepredictivevaluewere95%and100%，1.00and1.00，0.90and1.00，0.90and1.00，0.91 and1.00，1.00and1.00，respectively.【Conclusions】PIstainingcandetectdeadMycobacterium tuberculosisand6-cFDA stainingcandetectliving Mycobacterium tuberculosis.Identificationof Mycobacterium tuberculosis activitybasedonPIand 6-cFDAstainingwillhavebroadapplicationprospects.
ABSTRACT
OBJECTIVE To evaluate the decontamination capability of hydrogel polymer coated ZnO nanoparticles (ZnO NP-gel) against soman. METHODS ZnO NP was synthetized using chemical precipitation method and modified with 4-pentenoic acid,and then polymerized with comonomers to obtain ZnO NP-gel. The transmission electron microscope (TEM), scanning electron microscope (SEM) and particle size instrument were used to observe the internal structure,micromorphology,particle size and zeta potential of these materials. An infrared spectroscope (IR) was used to analyze their chemical bond structure,while X-ray diffraction (XRD) was used to analyze the diffraction pattern.The content of soman was determined by benzidine chromogenic reaction. ZnO NP(1 g·L-1), ZnO NP-gel (1 g·L-1) and distilled water were mixed with soman(52.2 mg·L-1),stood for 30 min,and then filtered before filtrate was subcutaneously injected into mice (40 μL·g-1) to observe the symptoms of poisoning and death. RESULTS SEM and TEM showed that ZnO NP-gel had a block structure, the zeta potential of which was (-7.89 ± 0.04) mV. The results of IR indlicated that ZnO NP-gel had stronger absorption peaks at 754 and 618 cm-1, and XRD revealed that these materials had a sharp peak at 2θ=8.06738°. The decontamination efficiency of ZnO NP-gel was higher than that of ZnO NP group at the same concen?tration (n=3, P<0.05), and the time for decontamination of 50% soman was shortened by four times. The mice were injected subcutaneously with the soman solution treated with ZnO NP-gel, which caused no convulsion or death. CONCLUSION ZnO NP-gel can perform the double function of fast adsorption and catalysis of soman,and the decontamination ability of which could be improved through polymer modification.
ABSTRACT
OBJECTIVE To improve the poor water solubility and evaluating poor acitivity of etoposide (VP-16) by preparing VP-16 nanoparticle suspension (VP-16 NP) and its penetration through the blood-brain barrier (BBB).METHODS VP-16 NP was prepared with the anti-solution exchange method.The shape structure and diameter were observed with transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and dynamic light scattering (DLS), respectively. The drug release profiles of the VP-16 powder and VP-16 NP were measured.The effect of VP-16 NP on the growth of KB cells was observed via MTT assay. In addition, primary brain microvascular endothelial cells from 1stto 2nd generation of SD rats at two weeks of age were used to construct an in vitro BBB model.The classic 4 h leak test,trans-epithelial electrical resistance (TEER) test and fluorescein disodium salt(FLU)perme?ability test were conducted to verify whether the in vitro BBB model was successfully established.RESULTS VP-16 NP was a solid sphere with a size of 140 nm detected by TEM,SEM and DLS.The cumulative release rate of VP-16 NP was 3 times that of VP-16 powder. The results of MTT colorimetric assay showed that VP-16 powder had no inhibitory effect on KB cells,while VP-16 NP could effectively inhibit KB cells. In the 4 h leakage experiment, the top and bottom chambers of the Transwell cell model could maintain a liquid surface distance of >0.5 cm,indicating that the in vitro BBB model was initially formed.The effective resistance value of the TEER experiment was 223 Ω·cm2,indicating that the in vitro BBB model was basically established. In FLU permeability experiments, the permeability coefficients were respectively (0.33±0.04)×10-3,(0.42±0.07)×10-3,and (0.52±0.06)×10-3cm·min-1at 15,30 and 60 min, indicating that the model had low permeability.The above three experiments suggested that the BBB in vitro model was successfully constructed. On this basis, the in vitro BBB model was used to evaluate the penetration of VP-16 NP at a permeability coefficient of (1.87±0.03)×10-3cm·min-1at 30 min,showing high permeability.VP-16 NP showed better penetration of BBB.CONCLUSION VP-16 NP is success?fully prepared,which increases the release rate of the drug,enhances the killing effect of the cells,and shows good penetration through the in vitro BBB model evaluation.