To observe the local microcirculation changes in primary bone lengthening for gunshot bone defect treated by external fixators, the experimental study was carried out by using canine model of gunshot bone defect of extremities. 16 mongrel dogs were randomly divided into 2 groups, external fixators were used to distract early callus in one group and plaster was used for immobilization in the other group. The local microcirculation in the two groups was measured. The results showed: (1) Different from the normal fractures, the local blood flow of gunshot fractures was reduced in the first 3 days and then increased, at the 6th week it was close to the normal level. (2) There was no significant difference in the restoration of blood flow between the groups of external fixation and plaster immobilization. It is suggested that primary bone lengthening for gunshot bone defect by external fixators has no adverse effect on the restoration of the local blood flow.

To further understand the function and biological activity of TGF ? 1, and to provide the basis for the production of biologically active TGF ? 1 protein, TGF ? 1 cDNA was cloned into procaryotic expression vectors--pBV220 and pQE30, and the monomeric form of the recombinant TGF ? 1expressed in E.coli DH5? and M15. Sephacryl S 100 HR and Ni + NTA agarose column were used to purify the TGF ? 1 protein. With digestion of the enzymes and sequencing, TGF ? 1 mature peptide gene was inserted into procaryotic expression vectors--pBV220 and pQE30. After purified, the expressed products of two plasmids in E.coli showed a single protein on SDS--PAGE, and their expression levels were about 15% and 20% of the total bacterial protein. The construction of recombinant plasmids and preparation of the monomeric protein of TGF ? 1 lay a solid foundation for further studying the function of TGF ? 1 and producing biologically active TGF ? 1 protein.

Objective To investigate the pathological changes of bone in situ lengthening for the gunshot bone defect, and to discuss the practical feasibility and biological basis of bone lengthening in the conditions of periosteum damage. Methods The 38 canines were randomly distributed into two groups and sustained the same gunshot bone defect in the mid femoral diaphysis. In one group, the femur were stabilized with Bastiani external fixator and 2 weeks later the fractured limb with fixation were lengthened 2-4 times per day at a speed of 0.5-1 mm/d until the normal length was reached. The control group only had external fixation without lengthening. 3, 6 and 12 weeks after injury, the canines were given 99mTc MDP and got radionuclide examination under SPECT (ADAC company, USA.). Pathological and X ray observation were carried out at 1, 2 ,3 ,6 and 12 weeks respectively after injury for comparison between two groups. Results The X ray measurement showed that the length of callus distraction in the bone lengthening group increased by (2.82?0.94)cm and the relative lengthening of bone is 19.3% (15.8%-21.4% ), compared with normal femur on the same X ray film. The count of radionuclide increased gradually at the region of bone defect in the lengthening group. While in the fracture ends, no significant difference was found in the development pattern through each radionuclide observation phase between two groups. The main mode of osteogenesis was endochondral ossification and the bone defect area was enriched by chondrocyte in the bone lengthening group. Conclusion There are no obvious negative influence on bone turnover and local blood flow in the bone lengthening for gunshot bone defect. The remained periosteum and bone fragment under gunshot injury may have important role in the progression of osteogenesis. The neogenetic capillary provided not only blood supply for healing of bone but also source of osteocyte for bone lengthening in the case of the periosteum and blood circulation damaged with gunshot wound.

BACKGROUND: Some researches demonstrate that jog stress at fracture part can promote formation of callus, but molecular biological mechanism of jog stress on fracture healing is still unclear.OBJECTIVE:To study the effect of jog stress at fracture site on basic fibroblast growth factor(bFGF)at broken parts.DESIGN:Randomized controlled animal study.SETTING:Department of Orthopaedics,General Hospital of the Second Artilleryman of Chinese PLA;Departments of Orthopaedics and Pharmacy,the First Affiliated Hospital of General Hospital of Chinese PLA.MATERIALS:The experiment was carried out in the Animal Laboratory,the First Affiliated Hospital of General Hospital of Chinese PLA and the 8th Laboratory,Academy of Military Medical Sciences of Chinese PLA from March 2003 to April 2004.A total of 72 healthy purebred New Zealand rabbits,of general grade,5-6 months old,weighing 2.5-3.0 kg,were provided by Animal Center of Academy of Military Medical Sciences of Chinese PLA.All rabbits were randomly divided into jog group and fixation group with 36 rabbits in each group.And then,every 6 rabbits in both groups were respectively observed at 6 time points,including 7,14,21,28,42 and 56 days.METHODS:All animals were anesthetized with ketamine and sumian xinji.Fixation needle was rotated into 3,3.5,5.5 and 6 cm below platform of tibia,respectively,and then external fixators were installed.Chuck which was located at 1.5 cm from internal cortical bone and 4.5 cm below platform of tibia crossly cut off tibia.Fracture space was 2.0 mm and 2.5 mm in the fixation group and jog group,respectively.Animals in the fixation group were fixed with unilateral external fixator to dissect replace fracture part.In addition,animals in the jog group cut off their bone,fixed,and moved 0.5 mm to axis along central staff of external fixator.Animals were able to freely walk and external fixator was slightly shaken based on body mass of animal.Furthermore,all animals were sacrificed at 7,14,21,28,42 and 56 days after operation.According to the center of fracture part,samples in 1 cm length were cut,divided and fixed for 12 hours.Quantitative analysis of bFGF and colorized intensity were detected with immunohistochemical stain and JVC imaging analytic system at 7,14,21,28,42 and 56 days after operation.MAIN OUTCOME MEASURES:①Detecting colored intensity of bFGF;②quantitative analysis of bFGF.RESULTS:A total of 72 rabbits were involved in the final analysis bFGF could express in interstitial cells,vascular endothelial cell,osteoblast,chondroblast and osteocyte plasma.At 14,21 and 28 days after operation,positive indexes of bFGF protein in the jog group were 1.98±0.14,2.04±0.12 and 2.13±0.17,respectively,which were obviously higher than those in fixation group(1.59±0.14,1.68±0.15,1.63±0.27,P＜0.05).CONCLUSION:Jog stress can increase numbers of bFGF at fracture part and promote fracture healing.

BACKGROUND: Limb ischemia reperfusion (LIR) as a stressor leads to gastric mucosal injury, and then results in the occurrence of stress ulcer.OBJECTIVE: To observe the effects of LIR on gastric mucosal injury, investigate part of the mechanism, and the role of several transient limb ischemia in the occurrence of gastric mucosal injury.DESIGN: A randomized grouping design and controlled animal experiment.SETTING: Department of Pathophysiology of North China Coal Medical College.MATERIALS: The experiment was carried out in the pathophysiological laboratory of North China Coal Medical College from January to June 2002. Fifty-four healthy adult male Wistar rats were randomly divided into three groups with 18 rats in each group. Ischemia reperfusion (I/R) group: The rats were duplicated into models according to the Rosenthal method that under superficial anesthesia with ether, the roots of both hindlimbs were ligated by wrapping with rubber strap, blood flow was blocked for 4 hours and then recovered to perfusion for 4 hours, and finally killed by bleeding from abdominal aorta. Ischemic preconditioning group: Before model establishment, blood flow of both hindlimbs was blocked for 5 minutes, and then recovered to perfusion for 5 minutes, which was repeated for four times, and the following operations were the same as those in the I/R group. Control group: The operations were the same as those in the I/R group,but both hindlimbs were ligated at relaxation without blocking the blood flow.METHODS: Sections of gastric mucosa were prepared, and then observed under light microscope and electron microscope, and the index of gastric mucosal injury was determined according to the Guth standard. The colorimetric assay was performed with 721 spectrophotometer at 650 nm, and the amount of gastric combining mucus was calculated.Meanwhile, the blood flow of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus, content of nitric oxide in plasma and gastric tissue and activity of nitric oxide synthase (NOS) in gastric mucosa were determined.MAIN OUTCOME MEASURES: Index of gastric mucosal injury, amount of gastric combining mucus, blood flow of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus, contents of nitric oxide in plasma and gastric tissue and NOS activity in gastric mucosa.RESULTS: All the 54 rats were involved in the analysis of results. ① In the I/R group, gastric mucosal injury was serious, edema, hyperemia, erosion and disintegration of gland of mucosal glands were observed, infiltration of inflammatory cells (formation of ulcer) was observed in basal and inferior mucosa. In the ischemic preconditioning group, the gastric mucosa was complete, and the damaged severity was milder than that in the I/R group; Under electron microscope, the organell structures of gastric parietal and chief cells were incomplete and destroyed. The cell injuries in the ischemic preconditioning group were milder than those in the I/R group (index of injury: 18.00±10.71, 34.00±15.01, P＜ 0.01). ② The blood flow and combining mucosal amount of gastric mucosa, contents of phospholipid and hexosamine in gastric mucus in the ischemic preconditioning group and I/R group were all obviously lower than those in the control group [(2.12±0.56), (10.84±2.56), (25.52±2.97) mL/(kg·h); (2.01±0.91), (2.79±0.73), (3.99±0.87) mg;(7.68±1.95), (9.74±1.04), (11.98±1.98) mg/g; (3.83±1.18), (5.42±0.47), (5.76±1.21) mg/g, P ＜ 0.05, 0.01], those the above indexes were all higher in the ischemic preconditioning group than in the I/R group. ③ The contents of nitric oxide in plasma and gastric tissue and NOS activity in gastric mucosa in the ischemic preconditioning group and I/R group were significantly lower than those in the control group [(250.0±5.6), (270.0±11.3), (210.0±7.4) μmol/L; (9.34±0.67), (11.34±1.00), (7.50±0.67) μ kat/g, P ＜ 0.01], those were also signficantly higher in the ischemic preconditioning group than in the I/R group.CONCLUSION: As a stressor, LIR can lead to gastric mucosal injury, and cause stress ulcer.Ischemic preconditioning can alleviate the gastric mucosal injury following LIR

AIM: To observe the degree of gastric mucosal injury following limb ischemia/reperfusion(LIR),and to investigate the mechanism of gastric mucosal injury and the influence of the series of brief ischemia/reperfusion of hind limbs of rats on gastric mucosal injury. METHODS: Referring to Rosenthal's method, the model rats which underwent 4 hours of ischemia and 4 hours of reperfusion in hind limbs were made. The indexes of gastric mucosal injury after LIR and ischemic preconditioning (IPC) + LIR were determined. The morphologic changes were observed with light microscope and transmission electron microscop respectively. The GMBF,histologic lesion score, gastric barrier mucus, phospholipids, hexosamine, nitric oxide and nitric oxide synthase in mucus were measured in different groups. RESULTS: Serious damage in gastric mucosa was observed under microscope and EM after LIR. But less serious damage was observed in the IPC group. After LIR, compared to the control group, the GMBF and the content of gastric barrier mucus, phospholipids and hexosamine in mucus decreased significantly. There was significant difference in most indexes between the control group and the IPC group, but compared to LIR group, the histologic lesion score decreased significantly and the GMBF and the content of gastric barrier mucus, phospholipids, hexosamine ,nitric oxide and nitric oxide synthase in mucus increased significantly. CONCLUSION: LIR caused the gastric mucosa injury. IPC alleviated the damage of gastric mucosa following ischemia/reperfusion in hind limbs.

AIM: To study the distribution of nitric oxide synthase (NOS) in normal lung of rats, and the changes in distribution and activity of NOS in lung of rats suffering from limb ischemia reperfusion (LIR). METHODS: Using tourniquet, the model rats undergoing ischemia reperfusion were made. Using ?-ANDPH-d histochemical method, computer analysis of image and spectrophotography, the distribution of NOS in normal lungs of rats, and the changes in distributon and activity of NOS in lung of rats suffering from limb ischemia reperfusion (LIR) were observed. RESULTS: Histochemically, in normal rats, the NOS positive staining was found in epithelial cells of respiratory duct including bronchi, alveolar duct as well as in endothelium of pulmonary vessels, and the negative staining was found in pneumonocytes. In LIR rats, the above NOS staining were significantly stronger than that in normal one, and positive staining was also found in vascular smooth muscle and pneumonocytes. Biochemically, the results showed that the values of lung NOS, NO in LIR group increased significantly compared with the normal control. CONCLUSION: NO may play an important role not only in physiology of lung but also in pathophysiology of acute lung injury following LIR. [

Objective To introduce treatment of old scaphoid fractures by internal fixation with common screws which have been modified into compression-like ones.Methods Twenty-five patients with old scaphoid fracture were admitted to our department from January,1995 to December,2002.They were 17 cases of delayed union,and eight cases of non-union and pseudoarticulation formation.All the patients were treated with open re- duction anti internal fixation by modified common cortical bone screws,some threads of which bad been erased so that they could act somewhat like compression ones.The modified screws were driven into the reduced scaphoid by simple surgical instruments to fix and compress the fracture ends.Results Nineteen cases were followed up for one to six years (mean,3 years).Fourteen cases of fracture healed,with an average healing time of 7 months.The mean extension-flexion arc of the injured wrists was between 106 degrees and 128 degrees.Three cases failed to heal,and two cases experienced deformed and sunken proximal scaphoid.Conclusions Common cortical bone screws can be easily changed into compression-like ones to treat old scaphoid fractures and result in satisfactory,clinic outcome.In addition,they are easily available,can be inserted through joint facet with limited negative effect on the joint,and play a double role of compression and fixation.

OBJECTIVETo evaluate the role of muscle fatigue in the pathogenesis of high prevalence of low back pain(LBP) in drivers who work at high altitude, in order to seek the effective measures for prevention and treatment of LBP.

METHODThe spectral electromyographic(EMG) changes during isometric contraction of erector spinalis to fatigue in 26 drivers in the field were consecutively recorded after daily driving for 5 days. The relationship between the decline of median frequency and the development of the back extensor fatigue were analyzed.

RESULTSThe decline rates of EMG median frequency of the erector spinalis on 1-5 working day [(-0.258 +/- 0.087), (-0.248 +/- 0.070), (-0.256 +/- 0.097), (-0.267 +/- 0.093), (-0.274 +/- 0.081)%/s respectively] were significantly different from that of baseline measured before work [(-0.175 +/- 0.114)%/s, P < 0.05 or P < 0.01]. A positive correlation was also found between the decline rate and the working time(r = -0.809, P < 0.05).

CONCLUSIONThe high prevalence of LBP in the drivers working at high altitude is due to acumulative fatigue of back extensor resulting from long-distance driving, lack of proper rest, decrease of muscle endurance and increase of liability to fatigue, consequently leading to the muscle dysfunction and finally LBP.

Altitude ; Automobile Driving ; Electromyography ; Humans ; Low Back Pain ; etiology ; physiopathology ; Muscle Fatigue ; physiology ; Occupational Diseases ; etiology

OBJECTIVETo investigate the epidemiological characteristics of lower back pain of truck drivers in plateau areas with an analysis of the causes and evaluated the effects of the protective measures.

METHODSThe self-reported lower back symptom was investigated by questionnaire in 1,132 male drivers in plateau areas. Vibration of the driver lumbar back was measured real time with or without wearing corset. Study the effect of the special corset for drivers and the massage on back by self-control design of big sample intervention experiments.

RESULTSThe prevalence of lower back pain of drivers in plateau areas was 86.1%. High level of its prevalence is due to many factors. Special corset for drivers and massage on back by themselves can reduce the degree of the pain.

CONCLUSIONDriving in plateau areas is a special occupational work with high level of prevalence of lower back pain which can be prevented.

Automobile Driving ; Humans ; Low Back Pain ; epidemiology ; etiology ; prevention & control ; Male ; Occupational Diseases ; etiology ; prevention & control ; Prevalence ; Surveys and Questionnaires