Research and application of absorbable screw in orthopedics: a clinical review comparing PDLLA screw with metal screw in patients with simple medial malleolus fracture.

OBJECTIVE: To observe the therapeutic effect of absorbable screw in medial malleolus fracture and discuss its clinical application in orthopedics. METHODS: A total of 129 patients with simple medial malleolus fracture were studied. Among them, 64 patients were treated with poly-D, L-lactic acid (PDLLA) absorbable screws, while the others were treated with metal screws. All the patients were followed up for 12-20 months (averaged 18.4 months) and the therapeutic effect was evaluated according to the American Orthopaedic Foot and Ankle Society clinical rating systems. RESULTS: In absorbable screw group, we obtained excellent and good results in 62 cases (96.88%); in steel screw group, 61 cases (93.85%) achieved excellent and good results. There was no significant difference between the two groups. CONCLUSION: In the treatment of malleolus fracture, absorbable screw can achieve the same result compared with metal screw fixation. Absorbable screw is preferred due to its advantages of safety, cleanliness and avoiding the removal procedure associated with metallic implants.

Clinical efficacy of artificial skin combined with vacuum sealing drainage in treating large-area skin defects.

OBJECTIVE: To observe the clinical efficacy of artificial skin combined with vacuum sealing drainage (VSD) in treating large-area skin defects. METHODS: Totally 18 patients with skin defects, treated with artificial skin combined with VSD from September 2008 to May 2009 in our hospital, were retrospectively analyzed in this study. There were 15 males and 3 females, aged 7-66 years, 34.3 years on average. Among them, 10 cases had skin laceration caused by traffic accidents (7 with open fractures), 1 mangled injury, 1 blast injury, 1 stump infection combined with skin defects after amputation and 5 heel ulcers. RESULTS: All skin grafts in 16 cases survived after being controlled by VSD for one time. For the rest 2 patients, one with skin avulsion on the left foot was given median thickness skin grafts after three times of VSD, the other with open fractures in the left tibia and fibula caused by a traffic accident was given free flap transplantation. Skin grafts of both patients survived, with normal color and rich blood supply. CONCLUSION: Skin grafting in conjunction with artificial skin and VSD is much more effective than traditional dressing treatment and worth wide application in clinic.

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride nanoparticle as a novel delivery system for parathyroid hormone-related protein 1-34.

Chitosan (CS) and epoxy propyl trimethyl ammonium chloride (EPTAC) were used to prepare the water-soluble N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC). HTCC and sodium tripolyphosphate (TPP) were mixed to form HTCC nanoparticles based on ionic gelation. Parathyroid hormone-related protein 1-34 (PTHrP1-34) was incorporated into the HTCC nanoparticles. The particle size and morphology of nanoparticles were determined by transmission electron microscopy (TEM). HTCC/PTHrP1-34 nanoparticles were 100-180 nm in size and their encapsulation efficiency and loading capacity were related to HTCC concentration, TPP concentration and initial concentration of PTHrP1-34. Relatively optimum encapsulation efficiency (78.4%) and loading capacity (13.7%) of PTHrP1-34 is achieved, and the in vitro release profile of PTHrP1-34 from nanoparticles has an initial burst, which is followed up by a slow release phase. These studies showed that HTCC/PTHrP1-34 nanoparticles are suitable for the treatment of osteoporosis, because of their slow-continuous-release properties, and the relevant in vivo experiments and clinical trials should be further studied.

Mitotic arrest defective protein 2 expression abnormality and its clinicopathologic significance in human osteosarcoma.

Osteosarcoma is the most common primary malignancy of bone. Overexpression of mitotic arrest defective protein 2 (MAD2) is found in many human neoplasms, but its role in the oncogenesis of osteosarcoma is an untouched topic. The objective of this research was to observe the expression of MAD2 in human osteosarcoma and explore its clinicopathologic significance. MAD2 expression was analyzed in 48 primary osteosarcoma cases (19 osteoblastic osteosarcomas, 17 chondroblastic osteosarcomas and 12 fibroblastic osteosarcomas) using immunohistochemistry. A total of 20 normal bone specimens formed a control group. MAD2 was commonly overexpressed in human osteosarcoma. Immunopositivity was higher in tumors with lower differentiation and higher clinical stage. Increased expression of MAD2 was associated with earlier metastasis and poorer survival. Our findings provide evidence that MAD2 contributes to the pathogenesis and development of human osteosarcoma, Testing may have a clinical role in predicting prognosis, selecting appropriate chemotherapeutic strategies and providing novel strategies for osteosarcoma therapy.

Purification and Characterization of a Novel 21 kD Calcium-binding Protein from Rabbit Appendix Lymphocytes.

A novel 21 kD calcium-binding protein from rabbit appendix B lymphocytes has been purified and characterized. Through heat-denaturation, using Phenyl-Sepharose and DEAE-Sepharose chromatography, we obtained 5.3 mg SDS-PAGE homogeneous CaBP(21) from 1 kg lymphocyte cells. Amino acid analysis showed the acidic amino acid content (Asp + Glu) to be 26% after HCL hydrolysis. The blocking of the N-terminus of CaBP(21) prevents the de novo Edman degradation, like most of the other calcium-binding proteins. CaBP(21) has 46% of hydrophobic amino acid (with Gly, without Trp) content, 10% of basic amino acid content and 44% of acidic and polar amino acids. Peptide mapping and SDS-PAGE combined Sephadex G-25 gel filtration proves that CaBP(21) consists of two identical or similar subunits. Ca(2+)-binding assays using Arsenazo III indicated one protein to bind 4 Ca(2+) with dissociation constant (K(d)) for Ca(2+) about 10(-5) mol/L.