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Objective To study distributions of stiffness and stress of each component in internal fixation system for long bone fractures composed of fractured bones (including callus) and bone plates,and propose a method for determining bending stiffness of fracture internal fixation implants. Methods Based on the linear bending theory and composite beam theory, the mechanical model of femoral shaft internal fracture fixing system composed of fractured bones and bone plate was constructed and verified with the finite element model based on artificial femur CT data. The relationship between stress and stiffness of the internal fixation system for long bone fractures was established. Results The three stages (slow-rapid-steady growth) for variation of fractured bone bending stiffness with callus elastic modulus obtained by calculation and analysis were consistent with the three stages of actual bone healing process, which proved accuracy of the theoretical calculation method. Changing patterns for the neutral axis position of internal fracture fixing system composed of fractured bones and bone plate were further obtained, namely, the neutral axis position was close to (away from) the central axis of bone plate when stiffness of bone plate increased (decreased). According to the stress required for fracture healing (0.72-0.80 MPa), the reasonable range for bending stiffness of bone plate was 0.99-4.20 kN·mm2. Conclusions When elastic modulus of the callus was 0.037.00 GPa, bending stiffness of the fractured bones increased rapidly, which was at the stage of bone bridge formation. When elastic modulus of the callus was above 7 GPa, the callus tended to mature. Based on the femur model in this study, when thickness of bone plate was 3.6-6.0 mm and elastic modulus of fractured bones was 3.013.5 GPa, the entire fractured bone section could be effectively stimulated. In this study, when bending stiffness of bone plate was 0.99-4.20 kN·mm2 during the generation stage of bone bridge, it was conducive to bone healing.
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Internal fixator is usually adopted in the treatment of bone fractures. In order to achieve anatomical reduction and effective fixation of fractures, the placement of internal fixators should comply with the biology force line of the bone and adapt to the specific anatomical morphological characteristics of the cortical bone. In order to investigate the distribution characteristics and formation regularity of biology force line and cortical thickness of human bone, three-dimensional model of proximal femur is established by using three-dimensional reconstruction technique in this paper. The normal physiological stress distribution of proximal femur is obtained by finite element analysis under three kinds of behavior conditions: one-legged stance, abduction and adduction. The structural topology optimization method is applied to simulate the cortex of the proximal femur under the combined action of three kinds of behavior conditions, and the anatomic morphological characteristics of the proximal femur are compared. The distribution trend of biology force line of proximal femur and the characteristics of cortex are analyzed. The results show that the biology force lines of bone structure and the morphological characteristics of cortex depend on the load of human activities. The distribution trend of biology force line is related to the direction of trabecular bone and the ridge trend and firmness of cortex when bone is loaded physiologically. The proposed analytical method provides a solution to determine the biology force line of bone and the distribution characteristics of cortex. The conclusions obtained may guide the reasonable placement of internal fixator components of fracture.
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Objective To investigate the clinical efficacy of domestic terlipressin in the treatment of type II hepatorenal syndrome (HRS -II).Methods A total of 25 HRS -II patients admitted to our hospital from November 2011 to June 2014 were recruited into the treatment group,and 28 HRS -II patients treated with dopamine before 2011 were recruited into the control group.Patients in the treatment group were randomly divided into two subgroups:one subgroup (n =12)was given terlipressin once every 8 h,and the other subgroup (n =13) was given terlipressin once every 12 h.Both groups received albumin (Alb)infusion to expand the blood volume before treatment with terlip-ressin or dopamine,and the course of treatment was 7 days.The improvement in clinical symptoms,levels of blood urea nitrogen (BUN), serum creatinine and electrolytes,urine volume,changes in liver function,and ascites disappearance in the two groups before and after treat-ment were compared.Comparison of categorical data between the two groups was made by χ2 test,and comparison of continuous data was made by t test.Results Patients in the control group showed no obvious symptom relief,but those in the treatment group had varying de-grees of improvement in clinical symptoms.Neither group had significant changes in liver function and serum sodium level after treatment. The treatment group had significantly more patients whose ascites volume had decreased from large to medium than the control group (χ2 =5.705,P 0.05),whereas the urine volume showed significant difference after the treatment (t =15.534,P 0.05).Patients treated with terlipressin had mild and tolerable adverse reactions.Conclusion The domestic terlipressin combined with albumin infusion has good clinical efficacy and mild adverse effects in treating HRS -II.Its clinical application is highly recommended.
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Objective To observe the clinical effects and safety of scalp-body acupuncture and spine-manipulation therapy on preventively treating cervical cancer patients with postoperative urinary retention. Methods A total of 160 cases of cervical cancer patients with postoperative urinary retention were randomized into treatment group and control group, 80 cases in each group. Both groups were given conventional western medical treatment including preoperative indwelling of urethral catheter, clamping of urethral catheter 5 d after operation and release of the urine every 2-3 h, and trying to remove the urethral catheter 10-12 d after operation. Additionally, the treatment group received scalp acupuncture in the foot motor sensory area, body acupuncture of bilateral Shenshu (BL23) , Pangguangshu (BL28) , Ciliao (BL32) acupoints, and spine-manipulation therapy 5 d after operation. The clinical outcomes covered the incidence of urinary retention, residual urine volume, reset rate of catheter, and the clinical effect and safety in the two groups were evaluated. Results ( 1) The therapeutic effect of the treatment group was superior to that of the control group, and then the difference was significant (P<0.05). (2) After treatment, the incidence of urinary retention, residual urine volume, reset rate of catheter and average hospitalization days were less in the treatment group than those in the control group, the differences being significant ( P<0.05). ( 3) There was no adverse reaction during the treatment course. Conclusion Scalp acupuncture in the foot motor sensory area combined with body acupuncture and spine-manipulation therapy can promote the recovery of micturation function, and have satisfactory clinical effect and high safety in preventively treating cervical cancer with postoperative urinary retention.
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Objective To investigate the effects of Yun-Pi Prescription on hemolysin antibody,and approach its mechanism of regulating immune function.Methods Forty-eight KM mice were randomly divided into high,medium and low dose of Yun-Pi Prescription groups,which were given 20,10,5 mL/kg Yun-Pi Prescription respectively,and one control group with no intervention.From the seventh day,all groups were injected with chicken red blood cell for seven days.Levels of serum hemolytic optical density were measured in all groups.Results Compared with control group,levels of serum hemolytic optical density in Yun-Pi Prescription groups increased significantly(P
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Objective: To evaluate the reliability and effects of a compound bone substitute materials Bio-oss artificial bone grafts with recombinant human bone morphogenic protein-2(rhBMP-2) filling the alveolar bone defects around heterogenous replanted teeth. Methods:3 dogs′ bilateral mandible 3rd premolars(6 sites) were extracted. The defect sites without buccal and lingual alveolar bone were prepared for the heterogenous implanted teeth and the compound of Bio-oss and rhBMP-2 filled the alveolar bone defects around. The bone regeneration was observed by naked eye, radiograph, histology and histomorphometric analysis after 2, 3 months. Results:The new alveolar bone showed osteogenesis and calcification after 2 months, and intergrated with implanted teeth root under the light microscope and X ray. The new bone trabecular thickness(Tb.Th) augmented continuously. Differences of the bone area(B.Ar) and bone perimeter(B.Pm) were statistically significant after 2nd and 3rd month(P
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[Objective] To explore the genetic mechanism of acupoint catgut embedment in inhibiting hippocampal neuron apoptosis in rats with status epileticus (SE). [Methods] Forty SD rats were randomized into 5 groups: blank control (A), model (B), dilantin (C), routine acupuncture (D) and acupoint catgut embedment (E). Rat models of SE were established by intra-abdominal injection of penicillin. With immunohistochemical method, the expressions of apoptosisrelated genes of c-jun and bcl-2 were observed in the vulnerable neurons of the hippocampus 24 hours after modeling. [Results] Compared with SE model group, the expression of c-jun was decreased and the expression of bcl-2 was increased in group C, D and E 24 hours after modeling; c-jun expression was positively related with the apoptotic index (AI) and bcl-2 expression was negatively related; the effects in group E much differed from those in model group. [Conclusion] The possible mechanism of the acupoint catgut embedment in treating epilepsy is related to the inhibition of the hippocampal neuron apoptosis by prohibiting the expression of c-jun and promoting the expression of bcl-2.