BACKGROUND:Impact mechanics properties of thoracic vertebra cancellous bone should be understood in treating osteoporosis,bone remodeling,bone reconstruction,as well as fixator selection for thoracic vertebral fracture.Most of previous studies concerning youth and the elderly bodies alone,reports regarding impact of thoracic vertebra cancellous bone mechanical properties are few.OBJECTIVE:To perform impact experiment to the normal people youth and the elderly fresh corpse thoracic vertebra cancellous bone to survey the impact mechanical properties,and to definite whether the impact mechanical properties of thoracic vertebra trabecular bone have difference between youth and the elderly people.METHODS:Experimental samples were from 4 normal fresh corpse,aged 20,25,70 and 75 years,were provided by Department of Anatomy,Norman Bethune Medical University.Spinal column thoracic vertebra T_(3-12) specimen were obtained from corpse within 1 hours and cut into 40 mm×6 mm×6 mm pieces,with 20 test pieces in each group.The impact experiment was performed using energy liberation method at room temperature under 28 ℃.After experiment,the impact energy was displayed automatic on testing machine,and the impact toughness was calculated by mechanical formula,and the morphology of fracture surface was observed.RESULTS AND CONCLUSION:The impact energy and impact toughness of the youth group was obviously greater than that of the elderly group (P＜0.05).Majority of the fracture surfaces were comminuted,minority were transverse or oblique fracture.The macroscopic observation showed that trabecular arranged compact in the thoracic vertebra cancellous bone of the youth group,which was sparse arrangement and presented with senile osteoporosis in the elderly group.It demonstrated that the impact mechanics properties of thoracic vertebra cancellous bone are different between the youth and elderly groups,and osteoporosis changes impact mechanics properties in the elderly people.

The stress fracture is often resulted from forced march, heel-and-toe walking race, trudge over a longdistance etc. The stress fracture in metatarsal bone is very common. After analysis of bearing-force onmetatarsal bone, the feet are simplified as weight-bearing-cantilever beam structure, while the metatarsalbone as lever units which support the bending cantilever. 16 metatarsal bones were taken from freshcadavers of normal Chinese adults. TYPE 2H cantilever stress teeting machine was used for the experiment.This study analyzes the injury mechanism of stress fracture theoretically, the defines limit of stress fractureof the metatarsal bone, and makes biomechanical analysis for the fracture types. This experiment providesthe data and materials for prevention and diagnosis of stress fracture and the possibility of methods andpaths for stress fracture experiment of the biomaterials.

BACKGROUND:Thoracic or lumbar spine fracture and dislocation mainly treated by internal/external fixation devices with surgical methods.Fixation methods in treating spine fracture and dislocation is an important subject for scholars.OBJECTIVE:To quantitative analyze the treatment of spinal fracture and dislocation using pedicle screw and plate fixation,and to provide mechanical parameters for clinical application.METHODS:Shimadzu electronic universal testing machine was used to simulate L_1 lumbar fracture and dislocation treated by plate fixation and pedicle screw fixations,specimens were underwent flexion,extension,compression,as well as torsion tests,with speed of 5 mm/min.The torsion test was performed on the torsion machine with speed of 0.05 (°) / s.All the experimental data were analyzed by statistical analysis and paired t test.RESULTS AND CONCLUSION:The results demonstrated that the outcomes of compression test had no significant differences between 2 groups (P>0.05).The left and right torsion angle of the pedicle screw fixation group was smaller than that of the plate fixation group (P<0.05),and the flexion and extension displacements was smaller in the pedicle screw fixation group than in the plate fixation group (P<0.05).It suggested that plate fixation is worse than pedicle screw fixation,while pedicle screw fixation is conductive to bone healing,thus,pedicle screw fixation is a better internal fixation device.

Objective To investigate the effects of icariin, a major active component of traditional Chinese herb Epimedium on schizo-phrenia animal model. Methods MK-801, a N-methyl-D-aspartate (NMDA) receptor antagonist, was intraperitoneally injected into mice to establish a schizophrenia animal model. The open field behavior test infrared detection system was used to measure the mobility of mice in order to find the best optimal dose. 40 mice were randomly divided in to control group, model group, risperidone group and icariin group with 10 mice in each group. The risperidone group and the icariin group were given 0.1 mg/kg risperidone and 50 mg/kg icariin respectively. All groups were injected with 0.6 mg/kg MK-801 0.1 ml intraperitoneally, except the control group. The total distance and the central dis-tance within 210 minutes were tested. Results The total distance and the central distance were significantly longer in the model group than in the control group (P<0.001), and were shorter in the risperidone group than in the control group (P<0.05). The total distance was shorter in the icariin group than in the model group, but there was no significant difference (P=0.065); and the central distance was shorter (P=0.037). There was no significant difference in both total distance and the central distance between the risperidone group and the icariin group (P>0.05). Conclusion Icariin may improve the positive and negative symptoms of schizophrenia mice, which may be beneficial to schizo-phrenia therapy.

Objective To establish acute hepatotoxic model induced by Amanita exitialis and to study the characteristics of acute toxic liver failure induced by mushrooms containing peptide toxins,in hope for providing some help to experimental research on poisoning induced by mushrooms containing peptide toxins.Methods UPLC-MS/MS (Ultra performance liquid chromatography-tandem mass spectrometry) method was used to detect peptide toxins in Amanita exitialis.To establish acute toxic liver hepatic failure model,the beagles were fed with 60 mg/kg of lyophilized powder of Amanita exitialis fungus which encapsulated in starch capsules.Toxic sighs were observed,coagulation function,hepatic and renal function,liver histopathological morphology,peptide toxin concentration in plasma and urine were detected during the experiment.Results Total peptide toxins in Amanita exitialis was (3 482.6 ± 124.94) mg/ kg.All the beagles had toxic signs including vomiting and diarrhea in 12-48 h after ingestion.On 24 h after ingestion,the beagles' ALT,AST,TBIL,ALP,PT and APTT levels increased obviously.On 36 h after ingestion,the beagles' ALT,AST,PT and APTT values reached their peaks (ALT:283.2 ± 112.9 Kallmann unit;AST:223.9 ±93.8 Kallmann units;PT:132.9 ± 152.6 s;APTT:131.4 ± 153.9 s).On 48 h after ingestion,the beagles' TBIL and ALP levels reached their peaks (TBIL:23.3 ± 14.6 mol/L;ALP:274.5 ± 115.5 U/L).The beagles' TBIL,TP and APTT returned to normal 1 week after ingestion,their ALT,AST and ALP levels returned to normal 3 weeks after ingestion.Three dogs died during 24-72 h after ingestion.Liver histopathological morphology study showed hemorrhagic necrosis of hepatocytes.Peptide toxins can be detected in plasma within 24 h after ingestion.Peptide toxins can be detected in urine within 96 h after ingestion.Conclusion Amanita peptide toxins can cause hemorrhagic necrosis of liver cells and lead to acute liver failure.This model is consistent with clinical pathophysiological process of acute toxic liver failure induced by mushrooms containing peptide toxins,and it can be applied to the study of diagnosis and treatment of poisoning induced by mushrooms containing peptide toxins.

We have researched the viscoelastic properties of the cancellous bones of the os calcaneus, os lunatum and os capitalum. The compressing stress relaxation experiment and the creep experiment in the vertical, horizontal and 45 degree directions on the os calcaneus were performed. The data and curve of the compressing stress relaxation and creep were obtained. By masing regression analysis we worked out the compressing reduced stress relaxation and creep functions and curves. The results show that the quantities of compressing stress relaxation and creep of the calcaneus in the vertical direction are larger than those in the other two directions. The initial quantities of creep of the os capitalum are larger than those of the os lunatum, and there are no significant different between the quantities of stress relaxation of the cancellous bones of the os lunatum and os capitalum.
Adult ; Calcaneus ; physiology ; Elasticity ; Humans ; Linear Models ; Lunate Bone ; physiology ; Male ; Models, Biological ; Regression Analysis ; Skull ; physiology ; Stress, Mechanical ; Weight-Bearing ; physiology

The biomechanical properties of eight human corneas from four normal Chinese fresh corpses were investigated by use of one dimension tensile test, tensile stress relaxation and creep test. The destructive load, stretchy ratio, spreading stress, spreading strain and elastic modulus were determined. Also obtained were the stress relaxation and creep data and curves. After reduction of data, the reduced stress relaxation and creep data and curves were worked out. The regression method was used to get the regression coefficient. The least square method was employed to fit the data of stress and strain; then the stress-strain formula was expressed and the curves of human cornea were plotted. The constitutive equation is K (lambda,t) = G(t) T(e) (lambda) and some conclusions are drawn.
Biomechanical Phenomena ; Cornea ; physiology ; Elastic Modulus ; Humans ; Stress, Mechanical

OBJECTIVETo investigate the clinical efficacy of ligation of intersphincteric fistula tract (LIFT) in the treatment of simple anal fistula, including transphincteric anal fistula and insphincteric anal fistula.

METHODSClinical data of 52 patients with anal fistula receiving surgery treatment in Beijing Anorectal Hospital from January to October 2014 were analyzed retrospectively. Adoption of surgical procedure was based on rectal endoluminal ultrasound and patients' decision. Patients were divided into LIFT group and seton group. The two groups were compared in terms of operation time, blood loss, postoperative pain score, incidence of urinary retention, wound healing time, cure rate, recurrence, and the anal incontinence score.

RESULTSThere were 52 patients in the entire cohort including 28 cases of transphincteric anal fistula (14 cases of LIFT and seton placement groups) and 24 cases of intersphincteric anal fistula (12 case of LIFT and seton placement). The operation time was shorter in seton placement group in patients with two simple anal fistula [(23.9±5.0) min vs. (46.3±7.7) min, P<0.05]. LIFT postoperative pain score [(1.6±0.6) vs. (6.1±1.3)], wound healing time [(7.9±2.0) days vs. (30.0±5.1) days], postoperative hospital stay [(10.3±3.1) days vs. (20.7±7.1) days], and anal incontinence scores [(1.1±0.4) vs. (4.9±1.1)] were better than that of anal fistula seton (all P<0.05). There was no statistically significant difference in intraoperatie blood loss [(23.1±4.7) ml vs. (23.3±4.7) ml, P>0.05]. The cure rate of intersphincteric anal fistula was 83.3%(10/12) in LIFT group, and 100%(12/12) in the seton group. The cure rate of transphincteric anal fistula was 78.6% (11/14) in LIFT and 92.9%(13/14) in anal fistula seton group. There was no statistically significant difference (P>0.05).

CONCLUSIONIn the treatment of transphincteric fistula tract and intersphincteric fistula tract, LIFT procedures should be considered.

Digestive System Surgical Procedures ; Fecal Incontinence ; Humans ; Length of Stay ; Ligation ; Operative Time ; Pain, Postoperative ; Postoperative Period ; Rectal Fistula ; Recurrence ; Retrospective Studies ; Wound Healing

Objective:To investigate the variations of bromadiolone concentration in blood and its metabolism in rabbits after oral administration of bromadiolone, and to provide reference for the study of bromadiolone metabolism.Methods:Designed absolute alcohol (1 g/kg) reagent control group, high dose (0.3 mg/kg) and low dose group (0.05 mg/kg) , there were 6 rabbits in each group. Blood samples were collected from the rabbit central auricular artery at regular intervals as 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 24 h, 36 h, 48 h, 72 h, 168 h, 336 h, 504 h after oral administration. The samples were centrifuged within 1 h. Prothrombin time (PT) , activated partial thromboplastin time (APTT) and concentrations of bromadiolone in plasma were tested. Metabolic kinetics data was analyzed by DAS 3.0.2 software.Results:Bromadiolone had no significant effect on the body weight of the experimental rabbits during the experimental period ( P>0.05) . PT and APTT were significantly abnormal in different dose groups, but for occurrence of exception, PT was earlier than APTT. The concentration of bromadiolone in plasma reached the peak value 12 h after gavage in both high-dose and low-dose groups. The absorption time of t1/2Ka in high-dose group was 4.34 h, the clearance time of t1/2 was 81.52 h, the absorption time of t1/2Ka in low-dose group was 6.90 h, and the elimination time of t1/2 was 56.38 h. The atrioventricular model of bromadidone was three compartment model in rabbits. Conclusion:Bromadiolone can be absorbed rapidly by oral administration, but its metabolism is slow. The change of bromadiolone in vivo accords with the three compartment model.

Objective:To investigate the variations of bromadiolone concentration in blood and its metabolism in rabbits after oral administration of bromadiolone, and to provide reference for the study of bromadiolone metabolism.Methods:Designed absolute alcohol (1 g/kg) reagent control group, high dose (0.3 mg/kg) and low dose group (0.05 mg/kg) , there were 6 rabbits in each group. Blood samples were collected from the rabbit central auricular artery at regular intervals as 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 24 h, 36 h, 48 h, 72 h, 168 h, 336 h, 504 h after oral administration. The samples were centrifuged within 1 h. Prothrombin time (PT) , activated partial thromboplastin time (APTT) and concentrations of bromadiolone in plasma were tested. Metabolic kinetics data was analyzed by DAS 3.0.2 software.Results:Bromadiolone had no significant effect on the body weight of the experimental rabbits during the experimental period ( P>0.05) . PT and APTT were significantly abnormal in different dose groups, but for occurrence of exception, PT was earlier than APTT. The concentration of bromadiolone in plasma reached the peak value 12 h after gavage in both high-dose and low-dose groups. The absorption time of t1/2Ka in high-dose group was 4.34 h, the clearance time of t1/2 was 81.52 h, the absorption time of t1/2Ka in low-dose group was 6.90 h, and the elimination time of t1/2 was 56.38 h. The atrioventricular model of bromadidone was three compartment model in rabbits. Conclusion:Bromadiolone can be absorbed rapidly by oral administration, but its metabolism is slow. The change of bromadiolone in vivo accords with the three compartment model.