Purification of recombinant HBc antigen expressed in Escherichia coli and Pichia pastoris: comparison of size-exclusion chromatography and ultracentrifugation

Hepatitis B virus core protein (HBc) is an important serology marker of hepatitis B infection and patient follow-up. It is an M, 21,000 protein, which has the intrinsic capacity to self-assemble as a capsid-like particle. The hepatitis B core protein has been expressed in Escherichia coli and Pichia pastoris (three different constructions) in order to select a HBc recombinant antigen suitable for serodiagnosis requirements with a cost effective downstream strategy. The expression and purification of the different forms of recombinant HBc have been described. For the last step, ultracentrifugation and size-exclusion chromatography were compared. The morphology of these capsids was observed using an electron microscope. Our data shows that HBc antigen is produced in large quantities in E. coli but some contaminants remained which were associated with the E. coli HBc protein after ultracentrifugation or size-exclusion chromatography. The ultracentrifugation enables a higher purity of HBc antigen to be obtained than size-exclusion chromatography but the latter enables a higher recovery rate. P. pastoris enables the expression and extraction of a highly purified HBc antigen suitable for diagnostic purposes.     

Breast reconstruction after mastectomy for breast cancer: which reconstructive surgical procedure should be retained?

Post-mastectomy breast reconstruction represents a surgical option that may improve psychosocial outcome without modifying patients' survival. Psychosocial impact of used surgical technique and moment of realization of breast reconstruction remains unclear. However, complications are negatively related to patients' satisfaction. There is no guideline for BR indications. Therefore, a review of clinical and cosmetic outcomes of different breast reconstruction modalities was necessary. It permitted to propose a shared decision-making algorithm for the choice of moment and technique of BR according to the presence of radiotherapy that appears to be the main risk factor of clinical outcome of breast reconstruction. It also disclosed some limits in information reliability about clinical outcome of particular associations of breast reconstruction and radiotherapy. Proportion of women pursuing breast reconstruction, and particularly immediate breast reconstruction, is rising. Clinical surveys assessing relation between radiotherapy and clinical and psychosocial outcome of breast reconstruction are urgently expected.     

Inhibition of von Willebrand factor-GPIb/IX/V interactions as a strategy to prevent arterial thrombosis

Although drugs exist for the primary and secondary prevention of thrombosis, more potent antiplatelet drugs with sufficiently wide therapeutic windows to avoid bleeding complications are needed. Both academic and pharmaceutical laboratories are working to develop such drugs. This chapter reviews the potential of inhibiting interactions between von Willebrand factor (vWF) and the second most abundant receptor on the platelet, the glycoprotein (GP) Ib/IX/V complex, interactions that are essential for the activation of circulating platelets, contacting a vessel wall injury. Although still at the level of preclinical testing, this area is expected to progress quickly during the next few years, also in view of the three-dimensional structural information that has recently become available and that allows a molecular understanding of vWF binding to the GPIbalpha chain of the GPIb complex.