Li Shipu

Artificial bone of porous tricalcium phosphate ceramics and its preliminary clinical application

SummaryThe authors have prepared the artificial bone of porous tricalcium phosphate ceramics according to an appropriate formula and manufacturing technology. Physical and chemical testing shows that it possesses several distinguishing features: the communicating pores and macro/micropores; mean pore size, 380 μm (from 240 μm to 510 μm); porosity, 46.4 %; and compressive strength, 97.4 kg/cm2. It consists of CaO (49.09 %) and P2O5 (48.84 %). The testing of its biocompatibility shows that it is devoid of systemic or local toxicity, and free of irritation or foreign body response in tissues, and it does not result in hemolysis or mutation. The new bone readily grows into its pores with direct contact to the implanted material. 11 cases of bone defects were treated with this artificial bone with satisfactory results.

Biodegradation of tricalcium phosphate ceramics by osteoclasts

SummaryBiodegradation of tricalcium phosphate (TCP) ceramics was observed through mixed culture of osteoclasts and TCP discsin vitro in this study. Osteoclasts were isolated from newborn SD rat’s marrow of long bone and cultured on TCP discs. The culture terminated at the 48th h and 96th h respectively. Under an inverted microscope, the osteoclasts imparted round or oval body with multinuclear and many thin processes. These cells were positively stained for tartrate-resistance acid phosphatase (TRAP). Scanning electron microscope showed that many resorption lacunae on TCP disc surface and their diameters were smaller than 20 μm. Osteoclasts were located in the lacunae. At the 96th h, the resorption lacunae become larger and osteoclasts showed degeneration. It is suggested that osteoclasts possess ability to re-absorb TCP ceramics underin vitro culturing condition.

Studies on the ossification of compound transplantation of porous tcp ceramics and bone marrow

SummaryFollowing the culture of human red marrow with porous TCP ceramicsin vitro, a large amount culturing marrow cells adhered well to the surface and inner wall of TCP ceramics and spread well over the dish bottom 4 weeks after cultivation. After the compound transplantation of porous TCP ceramics with red marrow into quadriceps femoris muscle of rabbits, a huge amount of new bone and marrow formed in these sites on and in the ceramics 4 weeks after transplantation. These results showed an excellent biocompatibility between TCP ceramics and marrow and an excellent osteogenic effect in the compound transplantation. The mechanism of classification and clinical significance about the compound transplantation were discussed.

The bacterial inhibitory ability andin vivo drug release pattern of a new drug delivery system: Ciprofloxacine/tricalcium phosphate delivery capsule

SummaryThe bacterial inhibitory ability of a new drug delivery system (DDS): Ciprofloxacine/tricalcium phosphate delivery capsule (CTDC), itsin vivo drug release pattern, and the influence of ultrasonic irradiation on its drug release were investigated. It was found that CTDC had a strong and sustained inhibitory ability to some common pathogens of bone and joint infections, such as staphylococcus aureus, escherichia coli and pseudomonas aeruginosa.In vivo drug-release study in animals demonstrated a high concentration of ciprofloxacine in the bone tissue surrounding CTDC which was placed in the greater trochanter of the rabbit and continued to release ciprofloxacine for at least 5 weeks and the blood level of ciprofloxacine was low.In vivo study also showed ultrasonic irradiation could increase the amount of ciprofloxacine released from CTDC, which may be an economical, effecient and safe new method to achieve the control of drug release from DDS.

Experiments and clinical application of porous ceramic coating

SummaryA porous ceramic coating has been developed and its potential application as a means of skeletal fixation by bony ingrowth into the porous ceramic coating has been studied. Furthermore, a study of the physicochemical characteristics of the porous ceramic was carried out and a histological and mechanical evaluation of the implant interface made. Consistent bony ingrowth towards the implants was observed for a long time. A new type of hip prosthesis with porous ceramic coating, as well as the operative techniques and clinical results are presented