Objective To investigate the clinical application of self-settingcalcium phosphate cement (CPC) in bone defect repair of extremities. Methods From May 1998 to January 2000, 32 cases of bone defect, in 36 sites, were repairedand reviewed, aged from 4 to 59 years old (24.7 years old on average), with bone defect 2 to 125 cm2 in size (13.1 cm2 on average). The causes of the bone defect werefracture, bone cyst, iliac bone harvesting, fibrous dysplasia, enchondroma and bone tuberculosis, which involved femur, iliac, tibia, humerus, phalanx, fibula, calcaneus, talus and acetabulum. All of the cases were followed up for 1 to 23 months, 15.3 months on average, before radiographic examination. Results All operations were successful and no general response was observed in all of the cases. X-ray examination showed an integrity interface between CPC and bone. And CT showed no gap existed. There was no increase of serum calcium and phosphate levels. Conclusion CPC is applicable in the low- or non-weight-bearing site of the extremities.
The aim of this experiment was to study the osteogenesis in vivo of allogenic osteoblast combined culture with calcium phosphate composites. The osteoblasts were obtained by enzymatic digestion of periosteum from fibula subcultured to 13 generations, the cells were combined culture with hydroxyapatite and biphasic calcium phosphate. Subseguently, the composite was implanted into rabbits subcutaneously or intramuscularly. The blank material was implanted in the contralateral side as control. Four weeks later, all animals were sacrificed. All the implants were examined by gross observation, histological examination and EDXA. The results showed: 1. obvious ingrowth of connective tissue with very little inflammatory reaction; 2. new bone formation in the composites with deposit of Ca and P on the surface of osteoblast, but none in the blank materials; 3. no significant difference of new bone formation between the different sites of implantation or different materials, but those implanted intramuscularly had lamellae form of new bone while those implanted subcutaneously had only mineralization of extracellular matrix. The conclusion were: 1. the composites are biocompatible with prior osteogenesis property; 2. periosteal-derived allogenic osteoblasts obatined by enzymatic digestion could survive following implantation with bioactivity; 3. rich blood supply might be advantageous to new bone formation and its maturation.
Objective To study the effect and mechanism of the apoptosis of hypertrophic scar fibroblasts (HSF) induced by artesunate(Art). Methods HSFs were isolated and cultured from human earlobe scars by the tissue adherence method. The 3th to 5th generation cells were harvested and divided into two groups. HSF was cultured with normal medium in control group and with medium containing60, 120 and 240 mg/L (5 ml)Art in experimental group. Apoptosis and cell cycle were identified by light microscopy, electronmicroscopy and flow cytometry. Then, HSF was cultured with normal medium in control group and with medium containing 30, 60 and 120 mg/L Art in experimental group. The changes of intracellular calcium concentration were observed. Results The primary HSF was fusiform in shape and adherent. The vimentin positive expression was analyzed by immunocytochemistry. Art could induce apoptosis of HSF in the range of 60-240 mg/L under inverted microscope. The effect was dose and timedependent. Clumping of nuclear chromatin showed margination in the experimentalgroup. And the disaggregation of the nucleolus were observed under electronmicroscopy. There were significant differences in the proportion of HSF apoptosis and HSF at G0-G1,S, G2-M stages between the two groups(P＜0.05). Apoptotic peak was shown in experimental group by flow cytometry. The peak became more evident asArt concentration increased. The intracellular calcium concentration elevated markedly in HSF with 30-120 mg/L Art treatment for 24 hours, showing significant differences between the two groups (P＜0.05). Conclusion The Art facilitates HSF cells apoptosis in vitro by the change of cell cycle. It is suggested that intracellular calcium variation may be one of the mechanisms of HSF apoptosis induced by Art.
OBJECTIVE:To observe the effect of dexamethasone to intracellular free Ca2+ of frozen RPE cells. METHODS:The cultured human RPE cells were frozen for 30s at --70deg;C. The RPE cells were loaded with Fura-2/AM and analyzed using a digital imaging microscopy system,the effect of dexamethasone to intracellular free Ca2+ was measured at a serial concentration of 40, 60,100,150,200mu;g/ml. RESULTS:The concentration of intracellular free Ca in frozen human RPE cells was increased to 18.6%~29.8% by dexamethasone at concenlration of 40mu;g/ml~60mu;g/ml,while was decreased to 28.4%~35.2% at 150mu;g/ml~200mu;g/ml. CONCLUSIONS:Effect of dexamethasone showed two aspects of effect to frozen cultured human RPE ceils,that it was inhibitor at high concentration and stimulator at low concentration （Chin J Ocul Fundus Dis,1997,13: 86-88）
Objective To study the mechanism of compound of calcium phosphate(TCP) and platelet-rich plasma(PRP) in the treatment of femoral head necrosis.Methods The left femoral heads of 48 New Zealand white rabbits were frozen by liquid nitrogen as to make themodel of femoral head necrosis.Twenty-four rabbits were randomly chosen as theexperimental group and their femoral heads were filled with TCP/PRP. The other 24 rabbits were used as the control group and their femoral heads were filled only with TCP. They were sacrificed at 2, 4,8,12 weeks after operation. The specimens were examined with X-ray and histological study.Results At 2 weeks after operation,there was no significant difference in femoral headdensity between the two groups. Four weeks after operation, femoral head density decreased in both groups, while it decreased more in the control group. At 8,12 weeks after operation, the density of the femoral heads in both groups increased, and it was higher in the experimental group. Histology examination showed thatthere was no difference between the two groups 2 weeks after operation. The head became flat at 4 weeks. Control group had more defects. At 4,8,12 weeks, more repairs were observed in the experimental group than that in the control group. The amount and maturity of osteogenesis in experimental group were much more greaterthan those in control group．Bone histomorphometry showed that the volum of thetrabecular was larger in the experimental group (36.65%±7.22%,38.29%±4.28%，39.24%±3.42%) than that of control group(P＜0.05). Conclusion TCP/PRP does not only provide osteoblasts scaffold, butalso promotes bone formation and the head repair. TCP/PRP is a good biomaterialfor the treatment of femur head necrosis.
Objective To search the most suitable concentration of calcium in the medium for the basement membrane reconstruction in tissue engineering skin in vitro. Methods Composite chitosan tissue engineering skin was prepared according to previous studies. Four groups were included according to the concentrationof calcium (1.00, 1.45, 1.65 and 1.95 mmol/L respectively). After 7 days and 15 days of culture, the histological manifestation of basement membrane in tissue engineering skin was observed by hematoxylin amp; eosin staining and PAS staining, and collagen Ⅳ of basement membrane was detected immunohistochemicallyatthe dermalepidermal junction. Results This tissue engineering skin shared some histological features of normal skin, including a welldifferentiated stratifiedepidermis and a dense dermis. The epithelium in the group of 1.95 mmol/L calcium differentiated better than those in other groups. PAS staining showing a regularly red dying strap domain at the dermal-epidermal junction. Collagen Ⅳ was positively stained immunohistochemically at the dermalepidermal junction inthe tissue engineering skin. Conclusion The above results suggest that the medium with 1.95 mmol/L calcium should be suitable for the growth of composite chitosan tissue engineering skin and the reconstruction of basement membrane.
To introduce a rat model of the conversion of acute edematous pancreatitis (AEP) to necrotizing pancreatitis (ANP). One hundred and seven Sprague-Dawley rats were randomized in three experimental groups as follows: sham operation control group and AEP group and ANP group. AEP was induced by pancreatic duct ligation and exocrine stimulation, ANP was induced same as AEP，but with a large dose of dextran-110 (500mg/kg) intravenously. The serum concentration of amylase increased significantly in AEP group and ANP group. Cytosolic free Ca2+ concentration in isolated pancreatic acinar cells increased consistently after induction of ANP. Homorrhage, parenchymal necrosis and calcium deposits in acinar cells were observed in pancreas in ANP group. Ultrastructural examination showed desquamation and necrosis of the endothelium of the pancreatic capillary in ANP group. These results suggest that ischemia may induce the conversion of AEP to ANP via acinar cell Ca2+ overloading. The rat model would seem to be a suitable animal model for studying aggravating mechanism of acute pancreatitis.
Objective To investigate the biomechanical influence ofvertebroplasty using autosolidification calcium phosphate cement (CPC) on thoracolumbar osteoporotic fractures. Methods Four cadaver specimens with osteoporosiswere applied to make spine unit. There were 2 females and 2 males, whose average age was 69 years.All underwent flexion-axial loading to result in vertebral body fracture. Following reduction, the middle fractured vertebral body were strengthened by the method of vertebroplasty, using CPC. Before fracture and after vertebroplasty, all were conducted biomechanical test. Results After being packed- CPC to the space in the fractured vertebral body, the strength andstiffness in vertebroplastic group (2 285±34 N，427±10 N/mm) were significantly higher than that in osteoporotic group (1 954±46 N，349±18 N/mm) (Plt;0.05). The vertebral height changing in vertebroplastic group(5.35±0.60 mm) were significantly lower than that in osteoporotic group (5.60±0.70 mm) (Plt;0.05). And the fractured body increases its strength and stiffnessby 16.92% and 22.31% respectively in comparison with its initial situation. Conclusion After being injected CPC into bone trabecular interspaces, the fractured vertebral bodies can restore its strength and stiffness markedly.
Purpose To examine the change of optic disc blood flow in primary open angle glaucoma(POAG) patients after cold provocation test and nifedipine administration． Methods Using Heidelberg retinal flowmetry (HRF),the blood flow of optic disc of glaucoma patients and normal control subjects were measured under basal condition, after cold provocation test,and after nifedipine administration. Results The mean optic disc blood volume and flow of POAG patients reduced from 27.1 and 545.4 to 22.3 and 452.4 after cold provocation test (Plt;0.05),and increased to 29.0 and 579.5 after nifedipine adminstration(Plt;0.05).The changes of mean optic disc blood flow of patients with a history of cold extremities show statistic significance compared with whom without such history (Plt;0.05)). Conclusion The changes of blood flow of optic disc in POAG patients may be influenced by cold stimuli and administration of nifedipine,and the history of cold extremities might be connected with the change of optic disc blood flow in POAG patients. (Chin J Ocul Fundus Dis,2000,16:85-87)
PURPOSE:To approach the establishment of t be optimal method for determining the intracellular free Ca2+ concentration[Ca2+]i of dissociated newborn rabbit retina cells by using fluorescent indicator-Fura-2/AM. METHODS:Trypsin was employed to prepare the retlna cell suspensions which were then loaded with Fura-2/AM followed by fluorescence determination. RESULTS:The cellular viability rate of retina cell suspensiotls prepared by 0.05% trypsin 10 minutes at 37deg;C was over 90%. Loading the retina cell suspensions with Fura-2/AM 40 minutes at 37deg;C and then measurlng the fluorescent intensity of the suspensions within 30 minutes were proved to be the optimum. CONCLUSIONS:The resting [Ca2+]i of retina cell suspension was (223plusmn;27)nmol/L whlch was within the expected range of [Ca2+]i level. 25mmoI/L and S0mmol/L K+ increased the [Ca2+Ji 59% and 148% respectively. These results indicate that the preparation of retina cell suspensions and the method of [Ca2+Ji determination are reliable and feasible. （Chin J Ocul Fundus Dis,1996,12: 108-110 ）