[Repair of humeral fracture and non-union with transfer of vascularized periosteal flap]

OBJECTIVE

To study the results of humeral fracture and non-union repaired by vascularized periosteal flap transfer.

METHODS

The clinical data of humeral fracture and non-union in 23 cases were analysized retrospectively since 1995. Among them, minuted or several segmental fracture in 12 cases, non-union in 11 cases, and following injury of radial nerve in 7 cases. The operative method was open reduction, inner or external fixation with vascularized periosteal flap transfer.

RESULTS

The period of follow-up was 6 months to 2 years. The repair result of all patients was excellent and good, but elbow joint motion in 2 cases of non-union was not satisfactory. The periosteal flap had good osteogenic ability. The period of bone union was 2 to 5 months in humeral fracture and non-union. And function of radial nerve was recovery.

CONCLUSION

Transfer of distal humeral periosteal flap pedicled with radial collateral vessels is a better method for humeral fracture and non-union.

Mechanism of platelet aggregation induced by a monoclonal antibody requiring Fc portion

A monoclonal antibody designated Apt4, which is IgG1, was produced by fusion of mouse myeloma cells to spleen cells from a BALB/c mouse immunized with normal human platelets. Apt4 whole IgG caused the aggregation of both platelet rich plasma (PRP) and washed platelets from normal subjects and a patient with Bernard Soulier syndrome but not those from two patients with the Type 1 Glanzmann's thrombasthenia. No aggregation was observed when Apt4 F(ab')2 fragments were used. Immunofluorescence study showed that both whole IgG and F(ab')2 fragments of Apt4 bound to fresh or formalin fixed platelets from normal subjects and a patient with Bernard Soulier syndrome but not to those from two patients with Glanzmann's thrombasthenia. Aggregation induced by Apt4 IgG was inhibited by EDTA (10 mM), PGE1 (1 mM), 2-deoxy-D-glucose/antimycin (1.4 uM), and apyrase (20 units/ml). Preincubation of normal PRP with monoclonal anti-GPIIb/IIIa or anti-GPIb antibodies completely or partially inhibited the Apt4-induced aggregation, whereas anti-GPIIIa antibodies have no effects on this activation. Monoclonal ant-Fc gamma RII antibody (IV.3) inhibited Apt4 induced aggregation. Immunoprecipitation of 125I-labeled platelet membrane lysate by Apt4 IgG showed two protein bands with a molecular weight of 145,000 and 95,000 daltons respectively under non-reducing condition, which are corresponding to GPIIb and GPIIIa. In conclusion, Apt4 antibody binds to GPIIb/IIIa complex and induces aggregation, requiring energy metabolism, calcium, ADP release and Fc portion of IgG to interact with Fc receptor, but independent of thromboxane A2 formation.