Albumin Protein Impact on Early-Stage In Vitro Biodegradation of Magnesium Alloy (WE43).

Mg and its alloys are promising biodegradable materials for orthopedic implants and cardiovascular stents. The first interactions of protein molecules with Mg alloy surfaces have a substantial impact on their biocompatibility and biodegradation. We investigate the early-stage electrochemical, chemical, morphological, and electrical surface potential changes of alloy WE43 in either 154 mM NaCl or Hanks' simulated physiological solutions in the absence or presence of bovine serum albumin (BSA) protein. WE43 had the lowest electrochemical current noise (ECN) fluctuations, the highest noise resistance (Zn = 1774 Ω·cm2), and the highest total impedance (|Z| = 332 Ω·cm2) when immersed for 30 min in Hanks' solution. The highest ECN, lowest Zn (1430 Ω·cm2), and |Z| (49 Ω·cm2) were observed in the NaCl solution. In the solutions containing BSA, a unique dual-mode biodegradation was observed. Adding BSA to a NaCl solution increased |Z| from 49 to 97 Ω·cm2 and decreased the ECN signal of the alloy, i.e., the BSA inhibited corrosion. On the other hand, the presence of BSA in Hanks' solution increased the rate of biodegradation by decreasing both Zn and |Z| while increasing ECN. Finally, using scanning Kelvin probe force microscopy (SKPFM), we observed an adsorbed nanolayer of BSA with aggregated and fibrillar morphology only in Hanks' solution, where the electrical surface potential was 52 mV lower than that of the Mg oxide layer.

Long-term outcomes in a prospective cohort of apprentices exposed to high-molecular-weight agents.

RATIONALE: We conducted a long-term (8-yr) follow-up of 408 apprentices entering programs involving exposure to high-molecular-weight allergens. OBJECTIVES: The objectives were to assess the frequency of new and persisting sensitization, symptoms, and bronchial hyperresponsiveness in relation with job history after ending apprenticeship and to examine characteristics significantly associated with the incidence and remission of these occupational outcomes. METHODS: A respiratory symptom questionnaire, skin prick tests with work-related allergens (laboratory animals, flour, and latex), spirometry, and methacholine challenge were administered. The association between incidence or remission of these outcomes and individual characteristics at baseline and end of apprenticeship was examined. MEASUREMENTS AND MAIN RESULTS: In subjects who at any time during follow-up held a job related to their training (78%), the incidence of sensitization, rhinoconjunctival and chest symptoms, and bronchial hyperresponsiveness at follow-up was 1.3, 1.7, 0.7, and 2.0 per 100 person-years, respectively. The remission of these outcomes acquired during apprenticeship was 18.5, 9.6, 9.6, and 12.4 per 100 person-years, respectively, in subjects no longer in a job related to training. Several clinical, immunological, and functional characteristics at baseline and acquired during apprenticeship were found to be significantly associated with the incidence and remission of the outcomes. CONCLUSIONS: The incidence of sensitization, symptoms, and bronchial hyperresponsiveness was lower while at work than during the apprenticeship period. A high proportion of subjects in a job not related to training experienced remission of symptoms acquired during apprenticeship.