The use of beta-tricalcium phosphate and bone marrow aspirate as a bone graft substitute in posterior lumbar interbody fusion

Purpose: Due to the disadvantages of iliac crest bone and the poor bone quality of autograft gained from decompression surgery, alternative filling materials for posterior lumbar interbody fusion cages have been developed. β-Tricalcium phosphate is widely used in cages. However, data regarding the fusion rate of β-TCP assessed by computer tomography are currently not available. Materials: A prospective clinical trial involving 34 patients (56.7 years) was performed: 26 patients were treated with single-level, five patients double-level and three patients triple-level PLIF filled with β-TCP and bone marrow aspirate perfusion, and additional posterior pedicle screw fixation. Fusion was assessed by CT and X-rays 1 year after surgery using a validated fusion scale published previously. Functional status was evaluated with the visual analogue scale and the Oswestry Disability Index before and 1 year after surgery. Results: Forty-five levels in 34 patients were evaluated by CT and X-ray with a follow-up period of at least 1 year. Clinically, the average ODI and VAS for leg and back scores improved significantly (P \u3c 0.001). CT assessment revealed solid fusion in 12 levels (26.67 %) and indeterminate fusion in 15 levels (34.09 %). Inadequate fusion (non-union) was detected in 17 levels (38.63 %). Conclusion: The technique of PLIF using β-TCP yielded a good clinical outcome 1 year after surgery, however, a high rate of pseudoarthrosis was found in this series therefore, we do not recommend β-TCP as a bone graft substitute using the PLIF technique. 2012 Springer-Verlag Berlin Heidelberg

Generation of PHB from spent sulfite liquor using halophilic microorganisms

Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB

Benchmarking glycoform-resolved affinity separation – mass spectrometry assays for studying FcγRIIIa binding

The antibody- FcγRIIIa interaction triggers key immunological responses such as antibody dependent cellular cytotoxicity (ADCC), making it highly important for therapeutic mAbs. Due to the direct glycan-glycan interaction with FcγRIIIa receptor, differences in antibody glycosylation can drastically influence the binding affinity. Understanding the differential binding of mAb glycoforms is a very important, yet challenging task due to the co-existence of multiple glycoforms in a sample. Affinity liquid chromatography (AC) and affinity capillary electrophoresis (ACE) hyphenated with mass spectrometry (MS) can provide glycoform-resolved affinity profiles of proteins based on their differences in either dissociation (AC) or equilibrium (ACE) constants. To cross-validate the affinity ranking provided by these complementary novel approaches, both techniques were benchmarked using the same FcγRIIIa constructs. Both approaches were able to assess the mAb – FcγRIIIa interaction in a glycoform selective manner and showed a clear increase in binding for fully versus hemi-fucosylated mAbs. Also, other features, such as increasing affinity with elevated galactosylation or the binding affinity for high mannose glycoforms were consistent. We further applied these approaches to assess the binding towards the F158 allotype of FcγRIIIa, which was not reported before. The FcγRIIIa F158 allotype showed a very similar profile compared to the V158 receptor with the strongest increase in binding due to afucosylation and only a slight increase in binding with additional galactosylation. Both techniques showed a decrease of the binding affinity for high mannose glycoforms for FcγRIIIa F158 compared to the V158 variant. Overall, both approaches provided very comparable results in line with orthogonal methods proving the capabilities of separation-based affinity approaches to study FcγR binding of antibody glycoforms