Background: New monoclonal antibody-based assays for serum-free light chains (FLC) have become available. Methods: In a clinical study with 541 patients, the new N Latex FLC assays were compared with the Freelite ™ FLC assays and immunofi xation electrophoresis (IF). Results:Comparison of the different FLC kappa ( κ ) assays showed a slope of 0.99 with a deviation of 5.0 % , r s = 0.92, for FLC lambda ( λ ) a slope of 1.22, deviation 13.8 % , r s = 0.90 and for the κ / λ ratio a slope of 0.72, deviation -4.6 % , r s = 0.72. The concordance for the FLC κ assays was 91 % , for FLC λ 85 % and κ / λ ratio 95 % . The clinical sensitivity and specifi city of the κ / λ ratios in the study were comparable: 60 % and 99 % for the N Latex FLC assay and 61 % and 97 % for the Freelite ™ assay. In IF-FLC positive samples, the N Latex FLC κ / λ ratio scored 20/23 (87 % ) samples outside the reference range and Freelite ™ 21/23 (91 % ). For IF-FLC negative samples, N Latex FLC assay κ / λ ratio scored 338/350 (97 % ) within the reference range and Freelite ™ scored 332/350 (95 % ). Conclusions:The concordance scores and the clinical sensitivity and specifi city of the new N Latex FLC assays and Freelite ™ assays appeared comparable, but there are some differences in measurement of concentrations between the methods.

Semisynthetic, covalent streptavidin-DNA adducts are versatile molecular connectors for the fabrication of both nano- and microstructured protein arrays by use of DNA hybridization. In this study, the hybridization characteristics of six adduct species, each containing a different DNA sequence of 21 or 24 bases, have been compared. First, the adducts were conjugated to biotinylated alkaline phosphatase, and their binding to immobilized oligomer complements of similar lengths was quantified in a microplate assay. The binding efficiency observed varied to a great extent with the specific sequence of the oligonucleotide attached, and could not be predicted from affiliated thermodynamic data of duplex stability. To further elucidate the hybridization properties, the hybridization rate constants of association and dissociation (kassn and kdissn) have been determined for both unconjugated oligonucleotides and protein adducts, using a surface plasmon resonance biosensor. The kassn values observed for the oligonucleotides are in the range of 9 x 10(3) to 2 x 10(5) M[-1] s(-1) and correlate with structural properties of the probe strands. Up to 3-fold decreased kassn values were obtained for the corresponding protein adducts. Likewise, values were observed for kdissn ranging from 1.4 x 10(-4) to 1.9 x 10(-5) s[-1] for the oligonucleotides. The dissociation of the analogous protein conjugates was reduced by up to 5-fold. The extent of this decrease correlates with the formation of homodimeric or intramolecular aggregation of probe strands. A mechanistic model for explaining these data is based on attractive intramolecular interaction between the nucleic acid and protein moiety.

These findings demonstrate that the N Latex FLC κ/λ ratio in patients with renal failure did not differ from the reference limits for healthy controls.

PH is associated with a lower acute-phase and total IGF-I response and a higher HGF and IL-6 response compared with laparotomy. HGF and CRP responses had an influence on the prognosis.