OBJECTIVE To establish a liquid chromatography massspectrometry(LC-MS/MS)method for quantitatively determining the concentration of cepharanthine in rat plasma and tissue samples after intravenous injection of cepharanthine hydrochloride.METHODS ①The LC-MS/MS method was adopted.A Phenomenex C18(3.0 mm×50 mm,2.6 μm)column was employed with a mobile phase consisting of 0.05%formic acid-2 mmol·L-1 ammonium acetate-water solution and 0.1%formic acid-acetonitrile solution under gradient elution at a flow rate of 0.6 mL·min-1.The determination was performed using positive ion multiple reaction monitoring mode assays:cepharanthine(m/z:607.3→365.1)and buspirone(IS)(m/z:386.4→122.2).② Blood samples were collected from 6 SD rats at different time points following a single iv administration of cepharanthine to determine the concentration of the drug.The main pharmacokinetic parameters were calculated using a non-compartmental model.③72 SD rats were subjected to tissue distribution experiments after a single and multiple iv administra-tion of cepharanthine,and tissue samples were collected at six different time points(n=6)for the quanti-fication of drug concentrations.④ The whole blood plasma distribution ratio(Rb/p)of cepharanthine hydrochloride(7.5 mg·kg-1)in 3 SD rats was determined 2 h after iv administration.⑤The protein binding of cepharanthine to rat plasma and lung tissue homogenates was determined by equilibrium dialysis before the concentration of the free drug within the lungs was calculated.RESULTS ① An LC-MS/MS method for quantitatively determining cepharanthine in rat plasma and tissue homogenates was devel-oped,which demonstrated an excellent linear relationship(r2>0.999)within the concentration range of 2 to 1000 μg·L-1,with a lower limit of quantification at 2 μg·L-1.The obtained results met all the require-ments for accurate quantitative detection.②The main pharmacokinetic parameters of cepharanthine in rats following a single iv administration were as follows:C0=(686.91±238.43)μg·L-1,t1/2=(29.70±6.29)h,Vz=(62.70±7.93)L·kg-1,Vss=(62.55±11.28)L·kg-1,CL=(1.50±0.23)L·h-1·kg-1 and AUC(0-t)=(4.52±0.61)h·mg·L-1.③ Concentrations in tissues exceeded those in plasma after both a single and multiple iv administration,with the highest levels in the lung.The values of AUC(0-t)in lungs were(2 547.35±156.56)and(4 481.35±479.21)h·mg·L-1 after a single and multiple iv administration,respectively.④ The content of cepharanthine in blood cells was higher than that in plasma,and Rb/p was 3.5±0.8.⑤ After correction by the protein-binding rate,the minimum concentration of free drugs in the lungs(95.04 μg·L-1)exceeded the reported antiviral activity threshold against coronaviruses(EC50=60.67 μg·L-1).CONCLUSION An LC-MS/MS method has been established to rapidly and sensitively determine the concentration of cepharanthine in rat plasma and tissues.Following intravenous administration of ceph-aranthine hydrochloride,the pulmonary exposure level of the drug is significantly higher in plasma and other tissues,providing data for evaluating its in vivo pharmacological activities.

OBJECTIVE To establish a liquid chromatography massspectrometry(LC-MS/MS)method for quantitatively determining the concentration of cepharanthine in rat plasma and tissue samples after intravenous injection of cepharanthine hydrochloride.METHODS ①The LC-MS/MS method was adopted.A Phenomenex C18(3.0 mm×50 mm,2.6 μm)column was employed with a mobile phase consisting of 0.05%formic acid-2 mmol·L-1 ammonium acetate-water solution and 0.1%formic acid-acetonitrile solution under gradient elution at a flow rate of 0.6 mL·min-1.The determination was performed using positive ion multiple reaction monitoring mode assays:cepharanthine(m/z:607.3→365.1)and buspirone(IS)(m/z:386.4→122.2).② Blood samples were collected from 6 SD rats at different time points following a single iv administration of cepharanthine to determine the concentration of the drug.The main pharmacokinetic parameters were calculated using a non-compartmental model.③72 SD rats were subjected to tissue distribution experiments after a single and multiple iv administra-tion of cepharanthine,and tissue samples were collected at six different time points(n=6)for the quanti-fication of drug concentrations.④ The whole blood plasma distribution ratio(Rb/p)of cepharanthine hydrochloride(7.5 mg·kg-1)in 3 SD rats was determined 2 h after iv administration.⑤The protein binding of cepharanthine to rat plasma and lung tissue homogenates was determined by equilibrium dialysis before the concentration of the free drug within the lungs was calculated.RESULTS ① An LC-MS/MS method for quantitatively determining cepharanthine in rat plasma and tissue homogenates was devel-oped,which demonstrated an excellent linear relationship(r2>0.999)within the concentration range of 2 to 1000 μg·L-1,with a lower limit of quantification at 2 μg·L-1.The obtained results met all the require-ments for accurate quantitative detection.②The main pharmacokinetic parameters of cepharanthine in rats following a single iv administration were as follows:C0=(686.91±238.43)μg·L-1,t1/2=(29.70±6.29)h,Vz=(62.70±7.93)L·kg-1,Vss=(62.55±11.28)L·kg-1,CL=(1.50±0.23)L·h-1·kg-1 and AUC(0-t)=(4.52±0.61)h·mg·L-1.③ Concentrations in tissues exceeded those in plasma after both a single and multiple iv administration,with the highest levels in the lung.The values of AUC(0-t)in lungs were(2 547.35±156.56)and(4 481.35±479.21)h·mg·L-1 after a single and multiple iv administration,respectively.④ The content of cepharanthine in blood cells was higher than that in plasma,and Rb/p was 3.5±0.8.⑤ After correction by the protein-binding rate,the minimum concentration of free drugs in the lungs(95.04 μg·L-1)exceeded the reported antiviral activity threshold against coronaviruses(EC50=60.67 μg·L-1).CONCLUSION An LC-MS/MS method has been established to rapidly and sensitively determine the concentration of cepharanthine in rat plasma and tissues.Following intravenous administration of ceph-aranthine hydrochloride,the pulmonary exposure level of the drug is significantly higher in plasma and other tissues,providing data for evaluating its in vivo pharmacological activities.

Objective: To study the effects of the palatal spur and chincup in the early treatment of anterior open bite in patients with Angle class Ⅰ malocclusion. Methods: Electronic search was conducted to find studies about the effects of the palatal spur and chincup in the early treatment of anterior open bite in patients with Angle class Ⅰ malocclusion. Data extraction and risk of bias assessment of included studies were conducted. RevMan5. 3 software was used fore Meta-analysis. Results: 6 clinical trials were qualified to the Meta-analysis. Compared to the control group, there was no significant change of skeletal measurments after treatment (P＞ 0. 05), and no significant change in dental measurments in chincup group (P＞ 0. 05) . While overbite, U1-PP (mm) and L1-MP (mm) were increased (P ＜ 0. 05), U1-NA (°) and L1-NB (°) decreased (P ＜ 0. 05) in the 3 groups of fixed palatal crib, bonded spur associated with the chincup and the removable palatal spur associated with the chincup. Conclusion: Chincup is not effective in the early treatment of the anterior open bite in patients with Angle class I malocclusion. But chincup combined with palatal spur or crib and have a positive effect on the closure of open bite through the palatal clination and extraction of the anterior teeth without influence of molar intrusion and skeletal change.

BACKGROUND: Schwann cells play an important role in axonal growth and myelin sheath formation of the peripheral nerve. Whether Schwann cells play the same role in the spinal cord had attracted considerable attention. Microencapsulation technology as an effective immune isolation technique can effectively keep Schwann cell activity to play the repair effect of Schwann cell in the spinal cord.OBJECTIVE: To observe the changes of myelin sheath in the injured transection of rats after transplantation of the alginic acid microencapsulated Schwann cells.DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed at the Basic Medical School of Nanchang University from March 2005 to February 2008.MATERIALS: Sciatic nerve trunk was obtained from adult rabbits to harvest Schwann cells in vitro using repeatedly differential velocity adherent technique, and to prepare Schwann cell suspension and microencapsulated Schwann cell suspension.METHODS: A total of 146 adult Sprague Dawley rats were used to establish models of right hemi-transection damage at T_(10) level and randomly assigned to four groups: simple injury group (n=44), cell transplantation group (n=44), microencapsulated cell transplantation group (n=44) and normal control group (n=14). At 1, 3, 7,14 and 28 days following surgery, 8 rats were selected from each group at each time point (2 from the normal control group) for perfusion and fixation. Spinal cord tissue was collected to make paraffin section, and then subjected to hematoxylin-eosin staining and Loyez myelin staining. In addition, 2 rats were selected from each group at 2 and 8 weeks. The spinal cord tissue was fixed, embedded in Epon816, stained using uranyl acetate and aluminum citrate, and then observed using an electron microscope.MAIN OUTCOME MEASURES: Neuron number and survival were observed surrounding the damaged region. Structural changes in the myelin sheath from spinal cord white substance at the damage site were measured.RESULTS: At 1 and 3 days following spinal cord injury, spinal neurons were degenerated and necrotic at damaged site, with reduced number of myelin sheath, loose structure, but above-mentioned was rare in the cell transplantation and microencapsulated cell transplantation groups. At 7 days, the reduced number of myelin sheath, with damaged structure was seen. The microencapsulated cell transplantation group was light. At 14 days, number of neurons was increased, with increased cell body, especially in the microencapsulated cell transplantation group. At 28 days, neurons gradually recovered, myelin sheath was gradually complete, with increased number in the microencapsulated cell transplantation group. There were significant differences compared with the simple injury and cell transplantation groups (P < 0.01). At 8 weeks, abundant myelin sheath was repaired, with new myelin sheath in the microencapsulated cell transplantation group.CONCLUSION: Microcapsule has immune isolation effects. Microencapsulated rabbit Schwann cells can promote the repair of rat spinal cord neurons and axonal myelinization.