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OBJECTIVE Paeoniflorin (PF) and albiflorin (AF) are the major active components of total peony glucosides(TPG)from Paeonia lactiflora Pal,which have many biological activities such as anti-inflammatory, antioxidation and anti-hypertension effects. The drug-drug pharmacokinetic interaction among PF,AF and TPG,the pharmacokinetic comparisons of AF between hypoxia and normoxia,the transport of AF cross the blood-brain barrier cell model and the transport of AF/PF/TPG cross Caco-2 cell model were investigated.METHODS A highly sensitive and rapid UPLC-MS method with multiple-reaction monitoring(MRM)scanning via electrospray ionization(ESI)source operating both in the positive and negative ionization mode was successfully developed and validated for simultaneous quantitation of PF and AF in rat plasma after an oral administration of PF,AF and TPG. RESULTS The validated and developed UPLC-MS/MS method was successfully applied to simultaneously determine the AF and PF concentration in rat plasma and investigate pharmacokinetic interactions after a single intragastrical ad-ministration of PF,AF,co-administration of PF with AF and TPG,respectively.The elimination of both PF co-administered with AF and PF in TPG were slower than those for PF alone and the distribution in the tissues was wider.The combination of PF with AF or TPG could significantly increase the values of the AUC, MRT and t1/2of the drug PF, and reduce the values of CL of PF. From a comparison of the main pharmacokinetic parameters among AF alone, AF combined with PF and AF in TPG, the values of the MRT and t1/2of AF in TPG were greater than that of AF alone,and there were statistically signifi-cant differences in these parameters(P<0.05,P<0.01).It was also noticed that AUC and Cmaxof PF in hypoxia rats were significantly decreased compared with that of normaxia rats, suggesting that there was a decreased exposure of PF in rats under hypoxia. The multiple active components in TPG may lead to DDIs between some P-gp substrates. CONCLUSION The clinical performance of total peony glucosides would be better than that of single constitute. The outcomes of the study are expected to serve as a basis for development of clinical guidelines on total peony glucosides usage.
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We observed the effect of vibration parameters on lumbar spine under different vibration conditions using finite element analysis method in our laboratory. In this study, the CT-images of L1-L5 segments were obtained. All images were used to develop 3D geometrical model using the Mimics10. 01 (Materialise, Belgium). Then it was modified using Geomagic Studio12. 0 (Raindrop Geomagic Inc. USA). Finite element (FE) mesh model was generated by Hypermesh11. 0 (Altair Engineering, Inc. USA) and Abaqus. Abaqus was used to calculate the stress distribution of L1-L5 under different vibration conditions. It was found that in a vibration cycle, tensile stress was occurred on lumbar vertebra mainly. Stress distributed evenly and stress concentration occurred on the left rear side of the upper endplate. The stress had no obvious changes under different frequencies, but the stress was higher when amplitude was greater. In conclusion, frequency and amplitude parameters have little effect on the stress distribution in vertebra. The stress magnitude is positively correlated with the amplitude.
Subject(s)
Humans , Biomechanical Phenomena , Finite Element Analysis , Lumbar Vertebrae , Physiology , VibrationABSTRACT
Objective To study dynamic characteristics of human lumbar spine using three-dimensional finite element method. Methods Finite element model of lumbar spine (L1~5) was developed and validated based on CT images, and the modal analysis was also conducted. Results A total of top 30-order modal parameters were extracted to obtain dynamic characteristics of the lumbar spine under free boundary conditions. Resonance frequencies of the model were concentrately distributed, but the amplitude of each order varied greatly. Amplitude near L5 segment was much larger, indicating L5 was easily to be injured. This lumbar modal analysis could provide a basis for its further dynamic analysis. Parameters such as natural frequency, modal shape and vibration amplitude of the lumbar spine would be helpful for both lumbar dynamic analysis and optimal design of man-machine interface mechanical equipment.
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Objective To study biomechanical effects of the lumbar spine under different traction conditions by using three-dimensional (3D) finite element method. Methods The CT images of lumbar segment L1-5 were input to the Mimics 10.01 for developing 3D geometrical model of L1-5. Then the mesh model of L1-5 was obtained using Geomagic Studio 12.0 and Hypermesh 11.0. The finite element simulation of the lumbar spine under different traction conditions was made by using Abaqus. Results Head-down titling angle was related to the nucleus pulposus stress. When the head-down tilting angle was smaller than 10°, the nucleus pulposus stress regularly changed with the swing cycle; while the head-down tilting angle exceeded 10°, the stress was decreased. In the swing mode, the annulus inner ring stress was increased to promote intervertebral retraction. Conclusions The traction mode helps to relieve the lumbar pain with the swing helping to coordinate the traction effect in each direction, which can better sort out and relieve the rear facet joint disorders. In addition, patients should be careful to select the appropriate traction force in the treatment to achieve good therapeutic effect.
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Objective To study the effect of passive motion from lower extremity on electromyography (EMG) activity of major muscles when the back under head down tilting state. Methods Thirty healthy subjects were selected. The EMGs of erector spinal and trapezius muscles were recorded and analyzed when human body was under head-down tilting at angel of 0°, 10°, 20° and 27° in static mode, respectively, in sway mode (along the axis of Z with frequencies of 120 and 140/min， respectively) and in vibration mode (along the axis of Y with frequency of 680/min) with the help of multifunctional test bed. Results In the static mode, the median frequency (MF) decreased with the increase of head-down titling angle; in the sway mode, the MF at each of 4 head-down tilting angles was smaller than that in the static mode. When the frequency was 120/min, the MF decreased with head-down tilting angle increasing, but when the frequency reached 140/min, the variation of MF became irregular. In the vibration mode, the MF increased with the increase of head-down tilting angle and was larger than that in the static mode. Conclusions In the static mode, the muscle fatigue increased with the head down tilting angle increasing; in the vibration mode, smaller head-down tilting angle should be selected to achieve better treatment effect; but in the sway mode, larger head-down tilting angle would be better, and the sway frequency should be set lower than 120/min to avoid potential damage due to excessive muscle fatigue.
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Objective To investigate the diagnostic accuracy of 13C urea breath test (13C-UBT)in the diagnosis of Helicobacter pylori (Hp) infection in patients with gastric remnant.Methods A total of 94 gastric remnant patients (gastric remnant group) and 100 non-gastric remnant patients (control group) received 13C-UBT.According to the course of the disease,the gastric remnant group were divided into group 1 (29 cases,≤5 years),group 2 (33 cases,6 to 10 years) and group 3 (32cases,＞10 years).Before surgery,the diagnosis of Hp infection was according to 13C-UBT and gastric mucosa tissue staining.After surgery,the diagnosis was according to gastric mucosa tissue staining.The applying value of 13C-UBT in gastric remnant patients was evaluated.The consistency of results between 13C-UBT and gastric mucosa tissue staining were evaluated by the Kappa test.Results In gastric remnant group,the Hp infection rate after surgery (37.2％) was obviously lower than that before operation (79.8％;x2 =35.058,P＜0.01) and that of control group (77.0％).After surgery,the Hp infection rate of patients with Billroth Ⅱ gastrectomy (24.4％) was lower than that of patients with Billroth Ⅰ gastrectomy (47.2％ ; x2 =5.133,P=0.023).Before surgery,the Hp infection rate of gastric remnant subgroups were similar (P＞0.05).With the extension of the postoperative course,the Hp infection rate gradually decreased in gastric remnant subgroups (group 1:58.6％,group 2:36.4％,group 3:18.8％; x2=7.839,P=0.021).Setting the cut-off point at 2.0‰ in the gastric remnant group and 3.5‰ in the control group,the accuracy rate of diagnosis was the highest (92.6％ and 96.0％).There was good consistency between the results of 13C-UBT and gastric mucosa tissue staining (Kappa =0.84,P＜0.01).Conclusion With suitable operation and standard,13C-UBT may be a easy,safe and effective assay applied in the gastric remnant patients.