CEA Vitros ECi assay compared to four commonly used methods

44TH ANNUAL CSCC-CAMB-AACC CONFERENCE

than 0.5 ␮L/minute. The differences between the two results were not clinically significant; only one patient was positive. Conclusion: Our results suggest that either the assessment of sweat rate may have been inaccurate or that the sweat rate is not very critical. Errors in assessing the sweat rate may be due to late onset of sweating, tiring of sweat glands, or a loss of volume due to dead space. Given the enormous implications of this diagnosis, it is important that standardised procedures be followed to achieve both an accurate sweat collection and analysis. 21 ANALYSIS OF URINARY PROTEINS BY SDSAGAROSE GEL ELECTROPHORESIS IN MULTIPLE MYELOMA PATIENTS Le Bricon, T. , Benlakehal, M., and Bousquet, B. Laboratoire de Biochimie A, Hoˆpital St-Louis, 75010 Paris, France Objectives: SDS-agarose gel electrophoresis is a new technique which separates proteins according to their molecular weight (1). The usefulness of this technique has not been fully established for the routine laboratory analysis of proteinuria in myeloma patients. Methods: We consecutively evaluated 95 hospitalized patients (50H/45F, 60 ⫾ 11 years, serum monoclonal fraction: 30 ⫾ 19 g/L). Electrophoresis of urinary proteins was realized using the Hydragel prote´inurie威 kit (Sebia). Screening for total urinary protein was performed with the MultistixR strips (Bayer) followed by a pyrogallol red determination (Hitachi 747, Boehringer). Results: Total proteinuria ranged from 0.04 to 19.04 g/24h and was within normal range in 33% of patients (⬍0.15 g/24h). Urinary monoclonal light chains were detected in 61% of patients; 24h excretion varied from 0.04 to 18.2 g (by densitometric scanning of the gel). Seventy % of patients had an urinary profile by SDS-agarose gel electrophoresis suggesting an impaired renal function, more frequently of the glomerular type (67%), then tubular (28%) and mixed (5%). Light chain excretion was significantly associated with higher total proteinuria (KruskalWallis, p ⬍ 0.0001), discordance between strips and red pyrogallol protein measurements (khi2, p ⬍ 0.0001) and the presence of an abnormal urinary protein profile (p ⬍ 0.01). Conclusions: Evaluation of urinary proteins by SDSagarose gelelectrophoresis allows easy follow-up of light chain excretion (disease activity, therapeutic efficacy) and renal function in myeloma patients. Reference: 1. Clin Chem 1998; 44: 1191–7. 22 PLASMA CYSTATIN C: A BETTER MARKER OF GLOMERULAR FILTRATION RATE THAN CREATININE IN KIDNEY TRANSPLANTATION Le Bricon, T.,1 Thervet, E.,2 Froissart, M.,3 Benlakehal, M.,1 Bousquet, B.,1 Legendre, C.,2 and Erlich, D.4 Laboratoire de Biochimie A1, Service de Nephrologie2, Service de Physiologie3 (Hoˆpital Broussais), Laboratoire de Biochimie B4, Hoˆpital St-Louis, Av. Claude Vellefaux, 75010 Paris, France 232

Objectives: Plasma cystatin C is a more sensitive marker of acute changes in glomerular filtration rate (GFR) than creatinine in kidney transplant recipients (1). Long-term follow-up of renal function by cystatin C has not been yet investigated. Methods: GFR was measured in 25 patients (44 ⫾ 9 years, M/F: n ⫽ 11/14) 3 months after surgery by the 51Crlabeled EDTA. Cystatin C was measured by immunonephelometry (BN100, Dade-Behring) and creatinine by the Jaffe´ reaction (Hitachi 747, Boehringer). Their accuracy to estimate GFR was calculated from the relative increase in their concentration vs. their upper normal limits and the decrease in 51Cr-EDTA clearance vs. the lower limit of 80 mL/min/1.73m2. Statistical analysis was performed by linear regression and Kruskal-Wallis test (p ⬍ 0.05). Results: 51Cr-EDTA clearance ranged from 31 to 97 mL/ min/1.73m. The reciprocal of plasma creatinine correlated with 51Cr-EDTA clearance (r ⫽ 0.784, p ⬍ 0.0001). Plasma creatinine significantly overestimated GFR by 30% (7 false negatives). The reciprocal of plasma cystatin C correlated with 51Cr-EDTA clearance (r ⫽ 0.879, p ⬍ 0.0001): GFR (mL/min/1.73m) ⫽ 78 ⫻ (1/cystatin C in mg/L) ⫹ 4. Cystatin C significantly underestimated GFR by 15% with no false negatives. Conclusions: Plasma cystatin C appears superior to creatinine for evaluation of renal function in kidney transplanted patients. GFR can be rapidly estimated from plasma cystatin C using a formula independent of age, body surface and sex of the recipient. Reference: 1. Clin Chem 1999; 45: 2243–9. 23 CEA VITROS ECI ASSAY COMPARED TO FOUR COMMONLY USED METHODS Leclerc, P.,1 Gignac, S.,1 Massé, J.,2 Fruteau de Laclos, B.,1 Nadeau, L.1 and Turcotte, G.1 Service de biochimie1, CHAU de Que´bec, 1050, ch. Sainte-Foy, Que´bec, Canada G1S 4L8 and Service de biochimie2, CHU de Que´bec, 2705, boul. Laurier, Sainte-Foy, Canada G1V 4J2 CEA is measured on the Vitros ECi Immunodiagnostic System (Ortho-Clinical Diagnostics) with an immunometric technique involving a biotinylated antibody and a horseradish peroxidase-labeled antibody conjugate. Both antibodies are mouse monoclonal anti-CEA. The conjugate bound to streptavidin-coated wells is measured by a luminescent reaction. Objective: To compare the ECi assay to four other methods: DPC Coat-A-Count IRMA, Bayer Immuno 1, Abbott Axsym and Beckman Access. Methods: We selected 80 samples (range 0 to 1400 ␮g/L) and measured (within one calibration except for IRMA) CEA levels with each method (76 samples on the Access). We used Passing & Bablok regression (ECi ⫽ y) to calculate slope and intercept, least squares regression for r and sy/x and Wilcoxon signed rank test to compare mean values for samples within the reference range (ⱕ 5 ␮g/L) (n ⫽ 24). CLINICAL BIOCHEMISTRY, VOLUME 33, APRIL 2000

POSTER ABSTRACTS

Results:

25

Method (x)

IRMA

Regression Slope Intercept sy/x r

1,09 ⫺0,14 53,8 0,97

Immuno 1

Axsym

Access

1,14 0,11 55,6 0,97

1,00 0,21 48,0 0,98

1,23 ⫺0,30 47,2 0,97

Samples ⱕ 5 ␮g/L, ECi mean ⫽ 2,47 Eci-method mean ⫺0,01 0,38 p (Wilcoxon) 0,41 0,001

0,29 0,06

0,31 0,08

Conclusions: The systematic differences observed are of little significance. But, occasionally, we observed sample related differences between the five methods that are clinically significant. When changing methods, we recommend obtaining a baseline value with the new assay for patients being serially monitored.

24 DOWN-REGULATION OF THE NORMAL EPITHELIAL CELL-SPECIFIC 1 (NES1) GENE IS ASSOCIATED WITH UNFAVORABLE OUTCOME OF PROSTATE CANCER. Luo, L. Y., and Diamandis, E. P. Dept of Laboratory Medicine and Pathobiology, University of Toronto, Dept of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada Objectives: The Normal Epithelial Cell-specific 1 (NES1) gene encodes a novel serine protease, which is a new member of the expanding human kallikrein gene family. The NES1 gene was thought to act as a tumor suppressor gene. It has been found to be down-regulated in many established breast cancer cell lines. In order to investigate the role of NES1 gene in prostate cancer, we examined its expression at the mRNA level in 20 pair of normal and cancerous prostatic tissues. Methods: The NES1 expression levels between the cancerous prostatic tissue and its adjacent normal tissue were compared with the semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Results: Comparing the NES1 expression level between the cancerous prostatic tissue and its normal adjacent part, among these 20 pair of tissues, it was up-regulated in 8 pairs, down-regulated in 8 pairs and has no change in 4 pairs. However, among those 8 pairs that are upregulated, 7 pairs are R0positive (surgical margin negative). For those 8 pairs that are down-regulated, 7 pairs are R1 positive (surgical margin positive), indicating the down-regulation of NES1 is closely associated with R1 positive (p ⬍ 0.01). Conclusion: Considering R0 positive is a tumor pathological marker that indicates good prognosis, R1 positive is an unfavorable marker, we conclude that the down-regulation of NES1 in prostate cancer is closely related to unfavorable outcome. Its role as a new prognostic marker in prostate cancer should be explored further. CLINICAL BIOCHEMISTRY, VOLUME 33, APRIL 2000

EFFECT OF ATORVASTATIN (LIPITOR™) ON VLDLAPOB AND VLDL-TRIGLYCERIDE OVERPRODUCTION IN VIVO IN AN INSULIN RESISTANT HAMSTER MODEL Mangaloglu, L., Van-Iderstine, S., Chen, B., Taghibiglou, C., Cheung, R., and Adeli, K. Department of Laboratory Medicine & Pathobiology, Hospital for Sick Children University of Toronto, Toronto, Ontario, Canada M5G 1X8 Objective: A novel animal model of insulin resistance, the fructose-fed Syrian golden hamster, was employed to investigate the effect of atorvastatin, a potent HMG-CoA reductase inhibitor, on hepatic VLDL overproduction. Methods & Results: Fructose feeding for a two week period induced significant hypertriglyceridemia and hyperinsulinemia, and the development of whole body insulin resistance. Fructose feeding also induced a significant increase in hepatic secretion of VLDL-triglyceride and VLDL-apoB. In vivo feeding experiments were also performed in which several groups of three hamsters were fed a fructose-enriched diet for 14 days to induce the state of insulin resistance, followed by a fructose-enriched diet supplemented with 40 mg/kg atorvastatin for 7 to 14 days. Feeding protocol was as follows: Day 1–14, fructose feeding; Day 15–28, fructose ⫹/⫺ atorvastatin). Fructose feeding in the first two weeks caused a significant increase in plasma total cholesterol and triglyceride in both groups. However, there was a significant decline in plasma triglyceride levels following supplementation of the fructoseenriched diet with atorvastatin. This decline was not observed in control animals receiving a fructose-enriched diet without the drug. In addition, there was an average 43% decrease in VLDL-apoB production in hepatocytes isolated from hamsters fed atorvastatin compared to the control group. Intracellular apoB turnover was also significantly increased in livers of drug treated hamsters. Conclusions: Taken together, these data suggest that the assembly and secretion of VLDL particles in hamster hepatocytes can be acutely inhibited by atorvastatin in a process involving enhanced intracellular apoB degradation. 26 INVESTIGATION OF THE ROLE OF THE NC3 REGION OF THE COL9A1 GENE IN HEREDITARY EARLY ONSET PRIMARY OSTEOARTHRITIS OF THE KNEE AND HIP Nassar, B.A.,1 Ramsey, U.1,2 Gross, M.,2 Amon, M.A.1,2 Departments of Pathology1 and Surgery2, Dalhousie University, Halifax, Nova Scotia, Canada Objective: Osteoarthritis (OA) is characterized by breakdown of hyaline cartilage resulting in increased water content of articular cartilage. Recent studies have shown that early onset OA may be due to alterations in genes encoding the collagen matrix of hyaline cartilage. Of these, mutations in the COL9A1 gene, which encodes the interrupted helical (1 (IX) subunit of the type IX collagen molecule, were shown to cause OA-like symptoms in mice. 233