Expression, Purification, and Biochemical Characterization of Human Afamin.

Afamin is an 87 kDa glycoprotein with five predicted N-glycosylation sites. Afamin's glycan abundance contributes to conformational and chemical inhomogeneity presenting great challenges for molecular structure determination. For the purpose of studying the structure of afamin, various forms of recombinantly expressed human afamin (rhAFM) with different glycosylation patterns were thus created. Wild-type rhAFM and various hypoglycosylated forms were expressed in CHO, CHO-Lec1, and HEK293T cells. Fully nonglycosylated rhAFM was obtained by transfection of point-mutated cDNA to delete all N-glycosylation sites of afamin. Wild-type and hypo/nonglycosylated rhAFM were purified from cell culture supernatants by immobilized metal ion affinity and size exclusion chromatography. Glycan analysis of purified proteins demonstrated differences in micro- and macro-heterogeneity of glycosylation enabling the comparison between hypoglycosylated, wild-type rhAFM, and native plasma afamin. Because antibody fragments can work as artificial chaperones by stabilizing the structure of proteins and consequently enhance the chance for successful crystallization, we incubated a Fab fragment of the monoclonal anti-afamin antibody N14 with human afamin and obtained a stoichiometric complex. Subsequent results showed sufficient expression of various partially or nonglycosylated forms of rhAFM in HEK293T and CHO cells and revealed that glycosylation is not necessary for expression and secretion.

What is in a name? Oral and maxillofacial surgeon versus oral surgeon.

PURPOSE: In 1975, the American Society of Oral Surgeons officially changed its name to the American Association of Oral and Maxillofacial Surgeons. This change was intended to address the specialty's expanding surgical scope. However, today, many health care professionals continue to use the term oral surgeon. This study was undertaken to determine if students' perception of the oral and maxillofacial surgeon's (OMS) surgical scope would change when oral and maxillofacial surgeon was used instead of oral surgeon. MATERIAL AND METHODS: This cross-sectional study surveyed undergraduate and dental students' choice of specialist to treat 21 different conditions. The independent variable was the specialty term (oral and maxillofacial surgeon vs oral surgeon). The dependent variables were specialists chosen for the procedure (ear, nose, and throat surgeon; plastic surgeon; OMS or oral surgeon; periodontist; other). The test of proportions (z test) with the Yates correction was performed for data analysis. RESULTS: Of the 280 senior dental students who were surveyed, 258 surveys were included in the study. Dental students' perception of the OMS's surgical scope increased significantly from 51% to 55% when oral and maxillofacial surgeon was used instead of oral surgeon. Of the 530 undergraduate upper division science students who were surveyed, 488 surveys were included in the study. Undergraduate upper division science students' perception of the OMS's surgical scope increased significantly from 23% to 31% when oral and maxillofacial surgeon was used as an option instead of oral surgeon. CONCLUSION: The use of oral and maxillofacial surgeon increased students' perception of the OMS's surgical scope. This study also suggested that students were not fully aware of the magnitude of the OMS's scope of practice. The current dichotomy and inconsistent use of the specialty's official term adds to the confusion and to misunderstanding. Therefore, OMSs should universally refer to themselves as oral and maxillofacial surgeons and help educate others of their scope.