Lectin affinity electrophoresis of serum alkaline phosphatase in metastasized breast cancer.

The use of serum alkaline phosphatase (ALP) isoenzymes as markers of breast cancer metastases and treatment efficacy has received little attention. Twenty-six breast cancer women (56+/-13 years, all post-menopausal) were prospectively evaluated during their first and third course of chemotherapy (4-week interval). Serum samples were analyzed for ALP isoenzymes (bone, liver, and intestine) using a lectin affinity electrophoresis kit (Hydragel 15 ISO-PAL, Sebia) adapted on a semi-automated Hydrasys system (Sebia). Results were compared with imaging techniques for the presence of metastases; bone ALP isoenzyme (B-ALP) results were compared with C-Terminal degradation products of type I collagen (S-CTX) (CrossLaps, IDS Nordic). Serum B-ALP, but not S-CTX, confirmed the presence of bone metastases (BM) (n=15) with 67/100% sensitivity/specificity (using a 69 UI/L ROC cut-off); ROC AUC was 0.806 (P=0.0004) (NS for S-CTX). Chemotherapy reduced serum B-ALP by 24% over 4 weeks (P=0.0012); there was no change for S-CTX. There was no specific clinical pattern for other ALP isoenzymes (liver and intestine). In conclusion, serum B-ALP, but not S-CTX, could help confirm the presence of BM in breast cancer patients.

Evaluation of renal function in intensive care: plasma cystatin C vs. creatinine and derived glomerular filtration rate estimates.

Plasma cystatin C, a new marker of glomerular filtration rate (GFR), was prospectively evaluated in surgical intensive care. Cystatin C was measured (immunonephelometry, Dade-Behring) in 10 patients selected to cover a full range of GFR (phase I) and in 28 unselected consecutive patients followed for 5 days post-admission (phase II). Results were compared with (51)Cr-EDTA clearance (phase I only), plasma creatinine (kinetic Jaffe, Roche), 24-h or estimated by Cockcroft and Gault (CG) creatinine clearance (CrCl), and modified diet in renal disease (MDRD)-estimated GFR. In phase I, the highest correlation with(51)Cr-EDTA clearance (22-198 mL/min) was noted for CG CrCl (r(2): 0.883, p<0.001). During phase II follow-up, 24-h CrCl could not be calculated in 25% of daily evaluations. Cystatin C correlated with creatinine (0.856, p<0.0001) and CG CrCl with MDRD GFR (0.926, p<0.0001) in renal failure (10-78 mL/min, n=60). There was a +40% (p<0.001) median difference between cystatin C and creatinine (as a % of upper normal cut-off). Sensitivity/specificity to detect a <80 mL/min CG CrCl was 88/97% for cystatin C vs. 48/100% for creatinine (laboratory cut-off). In patients with normal and stable renal function (n=14), day-to-day intra-individual variation was 7.4% for cystatin C (vs. 10.6% for creatinine). In intensive care unit surgical adult patients, CG CrCl provides an easy and cost-effective estimate of GFR. Superior to creatinine, plasma cystatin C can be measured in selected patients where CG CrCl is known to be inaccurate.

Automated multicapillary electrophoresis for analysis of human serum proteins.

BACKGROUND: We evaluated a new, automated multicapillary zone electrophoresis (CE) instrument (Capillarys), 4.51 software version; Sebia) for human serum protein analysis. METHODS: With the Capillarys beta1-beta2+ reagent set, proteins were separated at 7 kV for 4 min in 15.5 cm x 25 micro m fused-silica capillaries (n = 8) at 35.5 degrees C in a pH 10 buffer with online detection at 200 nm. Serum samples with different electrophoretic patterns (n = 265) or potential interference (n = 69) were analyzed and compared with agarose gel electrophoresis (AGE; Hydrasys)-Hyrys, Hydragel protein(e) 15/30 reagent set; Sebia). RESULTS: CVs were <3.5% for albumin, <11% for alpha(1)-globulin, <4.1% for alpha(2)-globulin, <7.4% for beta-globulin, and <5.8% for gamma-globulin (3 control levels); measured throughput was 60 samples/h. In patients without paraprotein (n = 116), the median differences between CE and AGE were -5.4 g/L for albumin, 4.0 g/L for alpha(1)-globulin, 0.7 g/L for alpha(2)-globulin, 0.6 g/L for beta-globulin (P <0.001 for all fractions), and -0.1 g/L for gamma-globulin (not significant). More samples had at least one gamma-migrating peak detected by CE (n = 135 vs 130; paraprotein detection limit, approximately 0.5-0.7 g/L), but fewer were quantified (n = 84 vs 91) because of gamma- to beta-migration shifts. There was a 1.2 g/L median difference between CE and AGE for gamma-migrating paraprotein quantification (n = 69; P <0.001). Several ultraviolet-absorbing substances (lipid emulsion, hemoglobin) or molecules (contrast agent, gelatin-based plasma substitute) induced CE artifacts. CONCLUSIONS: The Capillarys instrument is a reliable CE system for serum protein analysis, combining advantages of full automation (ease of use, bar-code identification, computer-assisted correction of alpha(1)-globulins) with high analytical performances and throughput.