Your browser doesn't support javascript.
loading
: 20 | 50 | 100
1 - 19 de 19
1.
Adv Mater ; : e2312300, 2024 Mar 29.
Article En | MEDLINE | ID: mdl-38552255

O3-type layered transition metal cathodes are promising energy storage materials due to their sufficient sodium reservoir. However, sluggish sodium ions kinetics and large voltage hysteresis, which are generally associated with Na+ diffusion properties and electrochemical phase transition reversibility, drastically minimize energy density, reduce energy efficiency, and hinder further commercialization of sodium-ion batteries (SIBs). Here, this work proposes a high-entropy tailoring strategy through manipulating the electronic local environment within transition metal slabs to circumvent these issues. Experimental analysis combined with theoretical calculations verify that high-entropy metal ion mixing contributes to the improved reversibility of redox reaction and O3-P3-O3 phase transition behaviors as well as the enhanced Na+ diffusivity. Consequently, the designed O3-Na0.9Ni0.2Fe0.2Co0.2Mn0.2Ti0.15Cu0.05O2 material with high-entropy characteristic could display a negligible voltage hysteresis (<0.09 V), impressive rate capability (98.6 mAh g-1 at 10 C) and long-term cycling stability (79.4% capacity retention over 2000 cycles at 5 C). This work provides insightful guidance in mitigating the voltage hysteresis and facilitating Na+ diffusion of layered oxide cathode materials to realize high-rate and high-energy SIBs.

2.
Chem Commun (Camb) ; 59(65): 9792-9802, 2023 Aug 10.
Article En | MEDLINE | ID: mdl-37527284

Hydrogen production from electrocatalytic water splitting driven by renewable energy sources provides a promising path for energy sustainability. The current water electrolysis technologies mainly use fresh water as feedstock, which will further aggravate the shortage of water resources in the world. Seawater has an innate advantage in large-scale electrolysis hydrogen production because of its abundant reserves. However, direct seawater electrolysis without any pre-treatment faces serious challenges due to the electrode side reactions and corrosion issues caused by the complex compositions of seawater. In this review, we first discuss the basic principles of seawater electrolysis. Second, the recent progress in designing efficient direct seawater electrolysis systems is discussed in detail, including catalyst design, electrolyser assembly, membrane regulation, and electrolyte engineering. In addition, the challenges and future opportunities are highlighted for the development of seawater splitting technologies toward large-scale hydrogen production.

5.
Chin Med J (Engl) ; 123(13): 1727-30, 2010 Jul.
Article En | MEDLINE | ID: mdl-20819637

BACKGROUND: The nervous system, through the vagus nerve and its neurotransmitter acetylcholine, can down-regulate the systemic inflammation in vivo, and recently, a role of brain cholinergic mechanisms in activating this cholinergic anti-inflammatory pathway has been indicated. Galanthamine is a cholinesterase inhibitor and one of the centrally acting cholinergic agents available in clinic. This study aimed to evaluate the effect of galanthamine on circulating tumor necrosis factor alpha (TNF-alpha) in rats with lipopolysaccharide-induced peritonitis and the possible role of the vagus nerve in the action of galanthamine. METHODS: Rat models of lipopolysaccharide-induced peritonitis and bilateral cervical vagotomy were produced. In the experiment 1, the rats were randomly divided into control group, peritonitis group, and peritonitis groups treated with three dosages of galanthamine. In the experiment 2, the rats were randomly divided into sham group, sham plus peritonitis group, sham plus peritonitis group treated with galanthamine, vagotomy plus peritonitis group, and vagotomy plus peritonitis group treated with galanthamine. The levels of plasma TNF-alpha were determined in every group. RESULTS: The level of circulating TNF-alpha was significantly increased in rats after intraperitoneal injection of endotoxin. Galanthamine treatment decreased the level of circulating TNF-alpha in rats with lipopolysaccharide-induced peritonitis, and there was significant difference compared with rats with lipopolysaccharide-induced peritonitis without treatment. The 3 mg/kg dosage of galanthamine had the most significant inhibition on circulating TNF-alpha level at all the three tested doses. Galanthamine obviously decreased the TNF-alpha level in rats with lipopolysaccharide-induced peritonitis with sham operation, but could not decrease the TNF-alpha level in rats with lipopolysaccharide-induced peritonitis with vagotomy. CONCLUSION: Cholinesterase inhibitor galanthamine has an inhibitory effect on TNF-alpha release in rats with lipopolysaccharide-induced peritonitis, and the vagus nerve plays a role in the process of the action of galanthamine.


Cholinesterase Inhibitors/therapeutic use , Galantamine/therapeutic use , Lipopolysaccharides/toxicity , Peritonitis/chemically induced , Peritonitis/drug therapy , Tumor Necrosis Factor-alpha/blood , Animals , Male , Peritonitis/blood , Rats , Rats, Sprague-Dawley
6.
Zhonghua Yi Xue Za Zhi ; 89(23): 1602-6, 2009 Jun 16.
Article Zh | MEDLINE | ID: mdl-19957504

OBJECTIVES: To investigate the potential risk factors of affecting progression from acute lung injury (ALI) to acute respiratory distress syndrome in severe trauma population. METHODS: Twenty potential risk factors of affecting progression of acute lung injury were examined by univariate and multivariate logistic analyses among the severe trauma patients in a retrospective study. RESULTS: All of 375 specially severe trauma patients with ALI were included for analysis. The six risk factors that affected the progression from acute lung injury to acute respiratory distress syndrome were sepsis, duration of trauma, APACHE II score, DIC, aspiration of gastric contents, and advanced age. Specific risk factors also affected different patient subpopulations at different degrees. CONCLUSION: Impact of sepsis, DIC and duration of trauma that predict progression of ALI exists throughout the entire treatment period while aspiration of gastric contents and APACHE II score might affect aggravation of ALI only during the early period; due to deterioration of pulmonary function and severely traumatic injury, advanced age is still an independent risk factor; patients with these risk factors need aggressive supportive cares as early as possible in order to prevent further aggravations.


Accidents, Traffic , Acute Lung Injury/complications , Respiratory Distress Syndrome/etiology , Adult , Aged , Female , Humans , Injury Severity Score , Male , Middle Aged , Respiratory Distress Syndrome/diagnosis , Retrospective Studies , Risk Factors
7.
Arch Orthop Trauma Surg ; 129(4): 507-13, 2009 Apr.
Article En | MEDLINE | ID: mdl-19221774

OBJECTIVE: To investigate factors that most influence urban road traffic injuries (RTI) mortality and morbidity. METHODS: The study used linked police and hospital records of RTI patients in the city of Hangzhou during the 3-year period 2004-2006. Three RTI outcome groups were included: (1) fatally injured; (2) severely injured; and (3) mildly injured persons. RESULTS: High risks for fatal road traffic accidents (RTA) were found on urban links, over weekend, during night hours, in male drivers who drove old vehicles without using seat belts, and at exceeding speeds, or with night time accidents and bad weather condition. In case of higher risk for all urban road users on urban junctions, the numbers on mildly injury cases were increasing. The highest combined risk for dying or being severely injured was found in male drivers driving at excessive speed, on urban links, and with night time accidents. CONCLUSIONS: Intensifying safety education of motor vehicle drivers, enhancing traffic management and keeping balance of "person-vehicle-road" system will greatly reduce the urban traffic accidents and casualties.


Accidents, Traffic/statistics & numerical data , Urban Population/statistics & numerical data , Accidents, Traffic/economics , Accidents, Traffic/mortality , Adult , Aged , China/epidemiology , Female , Hospitalization/economics , Humans , Injury Severity Score , Length of Stay , Male , Middle Aged , Odds Ratio , Risk Factors , Seat Belts/statistics & numerical data
8.
Chin J Traumatol ; 11(6): 368-71, 2008 Dec.
Article En | MEDLINE | ID: mdl-19032853

OBJECTIVE: To assess whether these characteristics of less misclassification and greater area under receiver operator characteristic (ROC) curve of the new injury severity score (NISS) are better than the injury severity score (ISS) as applying it to our multiple trauma patients registered into the emergency intensive care unit (EICU). METHODS: This was a retrospective review of registry data from 2 286 multiple trauma patients consecutively registered into the EICU from January 1,1997 to December 31, 2006 in the Second Affiliated Hospital, Medical School of Zhejiang University in China. Comparisons between ISS and NISS were made using misclassification rates, ROC curve analysis, and the H-L statistics by univariate and multivariate logistic progression model. RESULTS: Among the 2 286 patients, 176 (7.7%) were excluded because of deaths on arrival or patients less than 16 years of age. The study population therefore comprised 2 110 patients. Mean EICU length of stay (LOS) was 7.8 days ?2.4 days. Compared with the blunt injury group, the penetrating injury group had a higher percentage of male, lower mean EICU LOS and age. The most frequently injured body regions were extremities and head/neck, followed by thorax, face and abdomen in the blunt injury group; whereas, thorax and abdomen were more frequently seen in the penetrating injury group. The minimum misclassification rate for NISS was slightly less than ISS in all groups (4.01% versus 4.49%). However, NISS had more tendency to misclassify in the penetrating injury group. This, we noted, was attributed mainly to a higher false-positive rate (21.04% versus 15.55% for ISS, t equal to 3.310, P less than 0.001), resulting in an overall misclassification rate of 23.57% for NISS versus 18.79% for ISS (t equal to 3.290, P less than 0.001). In the whole sample, NISS presented equivalent discrimination (area under ROC curve: NISS equal to 0.938 versus ISS equal to 0.943). The H-L statistics showed poorer calibration (48.64 versus 32.11, t equal to 3.305, P less than 0.001) in the penetrating injury group. CONCLUSIONS: NISS should not replace ISS because they share similar accuracy and calibration in predicting multiple blunt trauma patients. NISS may be more sensitive but less specific than ISS in predicting mortality in certain penetrating injury patients.


Injury Severity Score , Multiple Trauma/classification , Adult , Chi-Square Distribution , Female , Humans , Intensive Care Units/statistics & numerical data , Length of Stay/statistics & numerical data , Logistic Models , Male , ROC Curve , Registries , Retrospective Studies
9.
Chin Med J (Engl) ; 121(11): 968-72, 2008 Jun 05.
Article En | MEDLINE | ID: mdl-18706242

BACKGROUND: Among the deaths due to trauma, about one half of the patients suffer from road traffic injury (RTI). Most of RTI patients complicate acute respiratory distress syndrome (ARDS) and severe multiple injuries. ARDS is a major contributor to morbidity and mortality in trauma patients. Although many injuries and conditions are believed to be associated with ARDS independent risk factors in trauma patients, their relative importance in development of the syndrome are undefined. We hypothesize that not all of the traditional risk factors impacting mortality are independently associated with patients strictly identified by traffic injury. This study aimed to sieve distinctive risk factors in our RTI population, meanwhile, we also hypothesize that there may exist significantly different risk factors in these patients. METHODS: This was a retrospective cohort study regarding RTI as a single cause for emergency intensive care unit (EICU) admission. Patients identified as severe RTI with post-traumatic ARDS were enrolled in a prospectively maintained database between May 2002 and April 2007 and observed. Twenty-three items of potential risk impacting mortality were calculated by univariate and multivariate Logistic analyses in order to find distinctive items in these severe RTI patients. RESULTS: There were 247 RTI patients with post-traumatic ARDS admitted to EICU during the study period. The unadjusted odds ratio (OR) and 95% confidence intervals (CI) of mortality were associated with six risk factors out of 23: APACHE II score, duration of trauma factor, pulmonary contusion, aspiration of gastric contents, sepsis and duration of mechanical ventilation. The adjusted ORs with 95% CI were denoted with respect to surviving beyond 96 hours EICU admission (APACHE II score, duration of trauma factor, aspiration of gastric contents), APACHE II score beyond 20 EICU admission (duration of trauma factor, sepsis, duration of mechanical ventilation) and mechanical ventilation beyond 7 days EICU admission (duration of trauma factor and sepsis). CONCLUSIONS: We have retrospectively demonstrated an adverse effect of six different risk factors out of 23 items in mortality of post-traumatic ARDS within severe RTI patients and, moreover, gained distinct outcomes in stratified patients under real emergency trauma circumstance. An impact of APACHE II score and pulmonary contusion contributing to prediction of mortality may exist in prophase after traffic injury. Sepsis is still a vital risk factor referring to systemic inflammatory response syndrome, infection, and secondary multiple organs dysfunction. Eliminating trauma factors as early as possible becomes the critical therapeutic measure. Aspiration of gastric contents could lead to incremental mortality due to severe ventilation associated pneumonia. Long-standing mechanical ventilation should be constrained on account of severe refractory complications.


Accidents, Traffic , Respiratory Distress Syndrome/mortality , Wounds and Injuries/mortality , APACHE , Adult , Aged , Cohort Studies , Female , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors
11.
Acta Pharmacol Sin ; 28(10): 1585-90, 2007 Oct.
Article En | MEDLINE | ID: mdl-17883944

AIM: To evaluate the protective effect of oral raloxifene on acute lung injury. METHODS: Thirty adult, male Sprague-Dawley rats each weighing 180-210 g were used and divided into 3 groups: the raloxifene-lipopolysaccharide (LPS)-HCl group (n=10), the LPS-raloxifene-HCl group (n=10), and the placebo group (n=10). All the rats were injected intraperitoneally (ip) with 5 mg/kg LPS, and raloxifene (30 mg/kg) was orally administered 1 h before and 14 h after LPS injection into the raloxifene-LPS-HCl and the LPS-raloxifene-HCl groups, respectively; the placebo group received nothing. Sixteen hours after LPS injection, all the animals were anesthetized and the femoral artery was cannulated. All the rats received a direct intratracheal (IT) injection of HCl (pH 1.2; 0.5 mL/kg). The mean arterial pressure (MAP) and blood gas concentrations were measured. Fifteen rats (5 in each group, respectively) underwent a micro positron emission tomography (microPET) scan of the thorax 4 h after HCl instillation. The wet/dry (W/D) weight ratio determination and histopathological examination were also performed. RESULTS: The rats in the LPS-raloxifene-HCl group had a lower [18F]fluorodeoxyglucose uptake compared with the rats in the placebo group (4.67+/-1.33 vs 9.01+/-1.58, respectively, P<0.01). The rats in the LPS-raloxifene-HCl group also had a lower histological lung injury score (8.20+/-1.23 vs 12.6+/-0.97, respectively, P<0.01) and W/D weight ratio (5.335+/-0.198 vs 5.886+/-0.257, respectively, P<0.01) compared to the placebo group. The rats in this group also showed better pulmonary gas exchange and more stable mean arterial pressure (MAP) compared to the placebo group. CONCLUSION: Raloxifene provides a significant protective effect on acute lung injury in rats induced first by LPS ip injection and then by HCl IT instillation.


Protective Agents/pharmacology , Raloxifene Hydrochloride/pharmacology , Respiratory Distress Syndrome/prevention & control , Administration, Oral , Animals , Blood Gas Analysis , Blood Pressure/drug effects , Fluorodeoxyglucose F18 , Hydrochloric Acid/administration & dosage , Hydrochloric Acid/toxicity , Hydrogen-Ion Concentration , Injections , Injections, Intraperitoneal , Lipopolysaccharides/administration & dosage , Lipopolysaccharides/toxicity , Lung/diagnostic imaging , Lung/metabolism , Lung/pathology , Male , Positron-Emission Tomography , Protective Agents/administration & dosage , Raloxifene Hydrochloride/administration & dosage , Rats , Rats, Sprague-Dawley , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/chemically induced , Selective Estrogen Receptor Modulators/administration & dosage , Selective Estrogen Receptor Modulators/pharmacology , Trachea
12.
Crit Care ; 10(4): R112, 2006.
Article En | MEDLINE | ID: mdl-16882338

INTRODUCTION: Early detection of pneumothorax in multiple trauma patients is critically important. It can be argued that the efficacy of ultrasonography (US) for detection of pneumothorax is enhanced if it is performed and interpreted directly by the clinician in charge of the patients. The aim of this study was to assess the ability of emergency department clinicians to perform bedside US to detect and assess the size of the pneumothorax in patients with multiple trauma. METHODS: Over a 14 month period, patients with multiple trauma treated in the emergency department were enrolled in this prospective study. Bedside US was performed by emergency department clinicians in charge of the patients. Portable supine chest radiography (CXR) and computed tomography (CT) were obtained within an interval of three hours. Using CT and chest drain as the gold standard, the diagnostic efficacy of US and CXR for the detection of pneumothorax, defined as rapidity and accuracy (sensitivity, specificity, positive predictive value, negative predictive value), were compared. The size of the pneumothorax (small, medium and large) determined by US was also compared to that determined by CT. RESULTS: Of 135 patients (injury severity score = 29.1 +/- 12.4) included in the study, 83 received mechanical ventilation. The time needed for diagnosis of pneumothorax was significantly shorter with US compared to CXR (2.3 +/- 2.9 versus 19.9 +/- 10.3 minutes, p < 0.001). CT and chest drain confirmed 29 cases of pneumothorax (21.5%). The diagnostic sensitivity, specificity, positive and negative predictive values and accuracy for US and radiography were 86.2% versus 27.6% (p < 0.001), 97.2% versus 100% (not significant), 89.3% versus 100% (not significant), 96.3% versus 83.5% (p = 0.002), and 94.8% versus 84.4% (p = 0.005), respectively. US was highly consistent with CT in determining the size of pneumothorax (Kappa = 0.669, p < 0.001). CONCLUSION: Bedside clinician-performed US provides a reliable tool and has the advantages of being simple and rapid and having higher sensitivity and accuracy compared to chest radiography for the detection of pneumothorax in patients with multiple trauma.


Multiple Trauma/diagnostic imaging , Pneumothorax/diagnostic imaging , Adult , Female , Humans , Male , Middle Aged , Multiple Trauma/complications , Pneumothorax/complications , Prospective Studies , Sensitivity and Specificity , Time Factors , Ultrasonography
13.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 34(5): 432-5, 446, 2005 09.
Article Zh | MEDLINE | ID: mdl-16216055

OBJECTIVE: To observe the sequential changes in biomechanical competence of the femoral neck and marrow cavity of the proximal femur in ovariectomized rats. METHODS: Bone mineral density (BMD) and biomechanical properties of the femoral neck and the structural dimension of the proximal femur were measured 0, 3, 6, 9, 12, 15, 18, 21 weeks after ovariectomy (OVX) or sham operation (Sham) in 6-month-old female SD rats. RESULTS: The BMD of femoral neck in OVX rats was significantly lower than that in Sham group 6 weeks after operation, (0.195 +/-0.028) g/mm(2) vs (0.225 +/-0.036) g/mm(2) (P=0.03). Nine weeks after operation,the failure load of femoral neck decreased about 10% in OVX group to that in Sham group, (89.6 +/-7.7)N vs (96.7 +/-7.5)N (P=0.05). The medullary cavity of proximal femur started to show difference 15 weeks after operation (3.834 +/-0.115)mm(2) vs (3.713 +/-0.114) mm(2) (P=0.03). CONCLUSION: BMD loss after ovariectomy is associated with a medullary expansion in proximal femur and biomechanical strength deterioration in femoral neck, which might be an important factor of prostheses loosening in the postmenopausal osteoporotic women.


Bone Density , Femur Neck/metabolism , Femur/metabolism , Animals , Arthroplasty, Replacement, Hip , Biomechanical Phenomena , Female , Humans , Osteoporosis, Postmenopausal , Ovariectomy , Prosthesis Failure , Random Allocation , Rats , Rats, Sprague-Dawley
14.
Chin J Traumatol ; 8(2): 111-6, 2005 Apr.
Article En | MEDLINE | ID: mdl-15769311

OBJECTIVE: To evaluate the influence of osteoporosis on the middle and late periods of fracture healing process through observing the histomorphological changes, bone mineral density and biomechanical properties in ovariectomized rats. METHODS: Eighty-four female SD rats of 4 months old were randomly divided into osteoporosis group and sham operation group, 42 in each. Rats in osteoporosis group were performed ovariectomy operation while those in sham operation group were given sham operation. A midshaft tibia fracture model was established 10 weeks after ovariectomy. Tibias were harvested 2, 4, 6, 12, 18 weeks after fracture for bone mineral density, histomorphological and biomechanical evaluation. RESULTS: Compared with the sham operation group, callus bone mineral density was 12.8%, 18.0%, 17.0% lower in osteoporosis group 6, 12, 18 weeks after fracture, respectively (P<0.05); callus failure load was 24.3%, 31.5%, 26.6%, 28.8% lower in osteoporosis group, and callus failure stress was 23.9%, 33.6%, 19.1%, 24.9% lower in osteoporosis group 4, 6, 12, 18 weeks after fracture, respectively (P<0.05). In osteoporosis group, endochondral bone formation was delayed, more osteoclast cells could be seen around the trabecula, and the new bone trabecula arranged loosely and irregularly. CONCLUSIONS: Osteoporosis influences the middle and late periods of fracture healing in the rat osteoporotic model. The impairment is considered to be the result of combined effects of prolonged endochondral calcification, high activated osteoclast cell and the deceleration of the increase in bone mineral density.


Fracture Healing , Osteoporosis/complications , Osteoporosis/physiopathology , Tibial Fractures/etiology , Tibial Fractures/physiopathology , Animals , Biomechanical Phenomena , Body Weight , Bone Density , Disease Models, Animal , Female , Osteoporosis/pathology , Ovariectomy , Rats , Rats, Sprague-Dawley , Reference Values , Tibial Fractures/pathology
15.
Chin J Traumatol ; 8(2): 121-5, 2005 Apr.
Article En | MEDLINE | ID: mdl-15769313

OBJECTIVE: To dynamically monitor the bone mineral density (BMD) and the histomorphological changes during fracture healing in a rat femoral fracture model and to explore the role of dual energy X-ray absorptiometry (DEXA) in evaluating bone fracture healing. METHODS: Sixty three-month-old female Sprague Dawley rats were used to establish right femoral fracture models. The BMD of the callus of the fractured right femur were scanned by DEXA at 2, 4, 6, 8, 10 and 12 weeks after operation, respectively. A light microscope was used to evaluate the callus of each rat at the same time. The corresponding segment of the left femur was taken as a control. RESULTS: The BMD at the fractured site increased significantly during the process of fracture healing, which shows an obvious healing trend. The callus BMDs were 29.5%, 48.3%, 85.3%, and 105.2% of the BMD of the control limb at 2, 4, 6 and 8 weeks after fracture, respectively. There was a significantly difference between the groups. A compatibility on time was found between the BMD and the histomorphological characteristics at the fractured site during the process of fracture healing. The fracture healing was almost completed at 8 weeks after fracture as assessed by its histomorphological characteristics when the callus BMD reached to 105.2% of the BMD of the control limb. The BMD of the distal metaphysis decreased until 12 weeks after fracture. CONCLUSIONS: DEXA can evaluate the mineralization of the callus during the fracture healing process accurately and quantitatively and is more sensitive than plain radiography in detecting impaired bone unions, which indicates that it may play an important role in monitoring fracture healing.


Absorptiometry, Photon , Femoral Fractures/diagnostic imaging , Femoral Fractures/physiopathology , Fracture Healing , Animals , Bone Density , Disease Models, Animal , Female , Femoral Fractures/pathology , Osteogenesis , Rats , Rats, Sprague-Dawley
16.
Zhonghua Yi Xue Za Zhi ; 84(14): 1205-9, 2004 Jul 17.
Article Zh | MEDLINE | ID: mdl-15387984

OBJECTIVE: To evaluate the influence of osteoporosis on fracture healing. METHODS: Eighty-four 4 months old female Sprague-Dawley rats were randomly divided into osteoporosis (OP) group and sham operation (SO) group, 42 in each. Rats in OP group were performed ovariectomy operation while those in SO group with sham operation. When osteoporosis formed 10 weeks after ovariectomy, midshaft tibia fracture model was established. Tibias were harvested 2 weeks (2 rats per group), 4 weeks (9 rats per group), 6 weeks (9 rats per group), 12 weeks (9 rats per group) and 18 weeks (7 rats per group) after fracture for bone mineral density (BMD), histomorphological and biomechanical evaluation. RESULTS: Compared with the SO group: (1) Callus BMD was significantly lower about 12.8%, 18.0%, 17.0% in OP group 6, 12, 18 weeks after fracture, respectively (P < 0.05). (2) Callus failure load was significantly lower about 24.3%, 31.5%, 26.6%, 28.8% in OP group, and callus failure stress was also significantly lower about 23.9%, 33.6%, 19.1%, 24.9% in OP group 4, 6, 12, 18 weeks after fracture, respectively (P < 0.05). (3) In OP group, endochondral bone formation was delayed, more osteoclast cell could be seen around the trabecula, and the new bone trabecula arranged loosely and irregularly. CONCLUSION: Osteoporosis influences the middle and late periods of fracture healing in the rat osteoporostic model. The impairment is considered to be the result of the combined effects of the prolonged endochondral calcification, high activated osteoclast cell and the deceleration of the increase in bone mineral density.


Bony Callus/physiopathology , Fracture Healing/physiology , Osteoporosis/physiopathology , Tibial Fractures/physiopathology , Animals , Bone Density , Bony Callus/pathology , Calcium, Dietary/pharmacology , Female , Osteoporosis/pathology , Ovariectomy , Random Allocation , Rats , Rats, Sprague-Dawley , Tibial Fractures/pathology
17.
Zhonghua Yi Xue Za Zhi ; 83(20): 1826-8, 2003 Oct 25.
Article Zh | MEDLINE | ID: mdl-14642093

OBJECTIVE: To dynamically observe the bone mineral density and histology changes during fracture healing at the femoral fracture site, and to study the role of monitoring fracture healing by dual energy X-ray absorptiometry (DEXA). METHODS: 60 female 3-month-old SD rats were used to establish right femoral fracture model. The fractured and contralateral unfractured femorals were scanned by Dual Energy X-ray absorptiometry in 2, 4, 6, 8, 10 and 12 weeks postoperatively. The callus of each rat was examined by light microscope at the same time. RESULTS: The value of bone mineral density at rat femoral fracture site was significantly increased post-osteotomy, showing a clear healing trend. The bone mineral density at fracture site was 29.5%, 48.3%, 85.3%, 105.2% of the value obtained of the control limb 2, 4, 6 and 8 weeks postoperatively. There was a compatibility on time between bone mineral density and histology. The BMD of distal metaphysis remained reduced until 12 weeks. CONCLUSION: The change of bone mineral density at the fracture site exhibited positive correlation with the histology of fracture healing, bone mineral density can accurately quantify the extent of mineralization of callus at the fracture site. DEXA can be used as a new technique in monitoring fracture healing.


Absorptiometry, Photon , Bone Density , Femoral Fractures/metabolism , Fracture Healing , Animals , Female , Femoral Fractures/pathology , Rats , Rats, Sprague-Dawley
18.
Chin J Traumatol ; 6(3): 160-6, 2003 Jun.
Article En | MEDLINE | ID: mdl-12749788

OBJECTIVE: To evaluate the effect of osteoporosis on fracture healing through observing the histomorphological changes, bone mineral density of callus and expression and distribution of transforming growth factor beta 1 (TGF-beta1), basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2) in ovariectomized rats. METHODS: Sixty female Sprague-Dawley rats (aged 12 weeks and weighing 235 g on average) were randomly divided into an ovariectomized (OVX) group (n=30) and a sham-operated (SO) group (n=30). Ovariectomy was performed in the OVX rats and same incision was made in the SO rats. Three months later, fracture of femoral shaft was made on all the rats. Then they were killed at different time points. Callus formation was observed with histological and immunohistochemical methods. RESULTS: A reduction in callus and bone mineral density in the healing femur and a decrease of osteoblasts expressing TGF-beta1 near the bone trabecula were observed in the OVX rats 3-4 weeks after fracture. Histomorphological analysis revealed a higher content of soft callus in the OVX rats than that in the SO rats. Immunohistochemistry results showed that no remarkable difference in expression and distribution of BMP-2 and bFGF between the OVX and SO groups was found. CONCLUSIONS: Osteoporosis influences the quantity and quality of callus during the early period of fracture healing. The effect of osteoporosis on fracture healing has no relationship with the expression of BMP-2 or bFGF. The decreased expression of TGF-beta1 in osteoblasts may cause a decrease in quality of fracture healing after osteoporosis.


Bony Callus/physiopathology , Femoral Fractures/physiopathology , Fracture Healing , Osteoporosis/physiopathology , Animals , Bone Density , Bony Callus/pathology , Disease Models, Animal , Female , Femoral Fractures/pathology , Humans , Immunohistochemistry , Osteoporosis/pathology , Ovariectomy , Rats , Rats, Sprague-Dawley , Time Factors
...