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 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 ）
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.
Objective To evaluate the clinical efficacy of oral calcium dobesilate(CaD) on diabetic optic neuropathy (DON).Methods The clinical data of 235 eyes of 235 patients with DON diagnosed by examination of ocular fundus were retrospectively analyzed.The patients were divided into 3 groups according to the subtypes of DON: anterior ischemic optic neuropathy(AION)group(71 eyes of 71 patients), papilloedema group (71 eyes of 71 patients),and neovascularization of disc (NVD) group (93 eyes of 93 patients).The patients in each groups were randomly subdivided into CaD treating group and control group, in which the patients underwent oral administraion of CaD at a dose of 500 mg twice per day or Vit.E at a dose of 10 mg twice per day,respectively.The course of therapy was 6 months and consecutive 2 courses were performed with the 3-4 days interval between the courses; the courses lasted for 6 months.Several parameters (VFD/V),EA/d,NA/d,LA/d) were semiquantitative analyzed 2,4,6,8 months after initial treatment. Repeated ANOVA measures and t test were used as statistical methods.Results In CaD group,VFD/V (0.25plusmn;0.10),EA/d (0.94plusmn;0.53), and LA/d(1.83plusmn;1.12) 2 months after initial treatment was obviously better than the results before the treatment (0.49plusmn;0.13,1.57plusmn;0.71,3.42plusmn;1.88)(P＜0.001), respectively.VFD/V,EA/d and LA/d in CaD group 2,4,6,and 8 months after initial treatment significantly differed from which in the control group (P＜0.01). There was significant difference of VED/V,EA/d,and LA/d between the CaD and control group during the follow-up period (P＜0.01).At each time point in the followup period, there was no significant difference of NA/d among groups and between the treating and control group (P＞0.05).Conclusion Oral administration of CaD can rapidly and remarkably decrease the extent of visual field defect,relieve optic disc edema and lessen the leakage of NVD.
OBJECTIVE: To study chondrogenesis of calcium alginate-chondrocytes predetermined shapes. METHODS: Chondrocytes isolated from ears of rabbit by type II collagenase digestion, and then were mixed with 1.5% solidium alginate solution. The suspension was gelled to create three spatial shapes as triangle, circle and quadrilateral by immersed into 2.5% CaCl2 for 90 minutes, and then was implanted into the subcutaneous pocket on the dorsum of the rabbit. Samples were harvested at 6 and 12 weeks after implantation. RESULTS: Gross examination of excised specimens at 6 and 12 weeks after implantation revealed the presence of new cartilage of approximately the same dimensions as the original construct. Histologic evaluation using hematoxylin and eosin stains confirmed the presence of cartilage nodules at 6 weeks after implantation. After 12 weeks, mature cartilage was observed and histologic analysis confirmed the presence of well formed cartilaginous matrix. CONCLUSION: Predetermined shapes neocartilage can be regenerated using calcium alginate as a carrier of chondrocytes in the bodies of immune animals.
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.
Mechanical signal transduction are crucial for chondrocyte in response to mechanical cues during the growth, development and osteoarthritis (OA) of articular cartilage. Extracellular matrix (ECM) turnover regulates the matrix mechanical microenvironment of chondrocytes. Thus, understanding the mechanotransduction mechanisms during chondrocyte sensing the matrix mechanical microenvironment can develop effective targeted therapy for OA. In recent decades, growing evidences are rapidly advancing our understanding of the mechanical force-dependent cartilage remodeling and injury responses mediated by TRPV4 and PIEZOs. In this review, we highlighted the mechanosensing mechanism mediated by TRPV4 and PIEZOs during chondrocytes sensing mechanical microenvironment of the ECM. Additionally, the latest progress in the regulation of OA by inflammatory signals mediated by TRPV4 and PIEZOs was also introduced. These recent insights provide the potential mechanotheraputic strategies to target these channels and prevent cartilage degeneration associated with OA. This review will shed light on the pathogenesis of articular cartilage, searching clinical targeted therapies, and designing cell-induced biomaterials.
Transcranial magneto-acoustic electrical stimulation (TMAES) is a novel method of brain nerve regulation and research, which uses induction current generated by the coupling of ultrasound and magnetic field to regulate neural electrical activity in different brain regions. As the second special envoy of nerve signal, calcium plays a key role in nerve signal transmission. In order to investigate the effect of TMAES on prefrontal cortex electrical activity, 15 mice were divided into control group, ultrasound stimulation (TUS) group and TMAES group. The TMAES group received 2.6 W/cm2 and 0.3 T of magnetic induction intensity, the TUS group received only ultrasound stimulation, and the control group received no ultrasound and magnetic field for one week. The calcium ion concentration in the prefrontal cortex of mice was recorded in real time by optical fiber photometric detection technology. The new object recognition experiment was conducted to compare the behavioral differences and the time-frequency distribution of calcium signal in each group. The results showed that the mean value of calcium transient signal in the TMAES group was (4.84 ± 0.11)% within 10 s after the stimulation, which was higher than that in the TUS group (4.40 ± 0.10)% and the control group (4.22 ± 0.08)%, and the waveform of calcium transient signal was slower, suggesting that calcium metabolism was faster. The main energy band of the TMAES group was 0?20 Hz, that of the TUS group was 0?12 Hz and that of the control group was 0?8 Hz. The cognitive index was 0.71 in the TMAES group, 0.63 in the TUS group, and 0.58 in the control group, indicating that both ultrasonic and magneto-acoustic stimulation could improve the cognitive ability of mice, but the effect of the TMAES group was better than that of the TUS group. These results suggest that TMAES can change the calcium homeostasis of prefrontal cortex nerve clusters, regulate the discharge activity of prefrontal nerve clusters, and promote cognitive function. The results of this study provide data support and reference for further exploration of the deep neural mechanism of TMAES.
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 methods of promoting the injectability of calcium phosphate cement.Methods Evaluation methods of bone cements, injectability and methods of promoting injectability were reviewed by extensive investigating of latest literatures.Results It was very important to improve the injectability of calcium phosphate cement. Commonly used methods to evaluate the injectability included testing injectability coefficient, pushing force and injection pressure.Injectability of calcium phosphatecement were promoted by increasing liquid/solid ratio, modulating the componentof solid or liquid phase, and adding various additives.Conclusion Promoting the injectability of calcium phosphate cement is the clinical requirement.
