| 1. |
- Kakonen, S M, et al.
(författare)
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Development and evaluation of three immunofluorometric assays that measure different forms of osteocalcin in serum
- 2000
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Ingår i: Clinical Chemistry. - 0009-9147. ; 46:3, s. 332-337
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Circulating human osteocalcin (hOC) has been used as a marker of bone formation. Our aim was to validate three immunofluorometric assays (IFMAs), measuring different forms of hOC. METHODS: The two-site IFMAs were based on previously characterized monoclonal antibodies. Assay 2 recognized intact hOC, assays 4 and 9 measured the NH(2)-terminal mid-fragment and the intact hOC. In addition, assay 9 required hOC to be gamma-carboxylated. RESULTS: A 76-79% increase of serum immunoreactive hOC was found in the postmenopausal group compared with the premenopausal group with all IFMAs. With EDTA-plasma samples, the observed increases were lower (49-65%). The hOC concentration in the postmenopausal group receiving hormone replacement therapy was 42-44% lower than that in the postmenopausal control group in both serum and EDTA-plasma samples. The depressed carboxylation in warfarin-treated patients was accompanied by lower results in assay 9. The ratio of assay 9 to assay 4 totally discriminated the warfarin-treated patients from the controls. Assay 9 showed the smallest decreases in measured hOC after storage of serum or plasma for 4 weeks at 4 degrees C, followed by assay 4 and assay 2. Results from the last assay were <17% of their initial values after 4 weeks of storage. No diurnal variation was observed with assay 9 as opposed to the two other IFMAs. CONCLUSION: The three assays with their distinct specificity profiles (intact vs fragmented and carboxylated vs decarboxylated hOC) may provide valuable tools for investigating the significance of different hOC forms in various bone-related diseases.
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| 2. |
- Ylikoski, A, et al.
(författare)
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Simultaneous quantification of prostate-specific antigen and human glandular kallikrein 2 mRNA in blood samples from patients with prostate cancer and benign disease
- 2002
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Ingår i: Clinical Chemistry. - 0009-9147. ; 48:8, s. 1265-1271
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Tidskriftsartikel (refereegranskat)abstract
- Background: Detection or quantification of circulating cancer cells has been proposed as an aid in detection and monitoring of several solid tumors. We investigated the classification accuracy of prostate-specific antigen (PSA) and human glandular kallikrein 2 (hK2) mRNA copy numbers in blood for the differentiation of patients with prostate cancer (PC) and benign disease. Methods: PSA and hK2 mRNA expression was studied in blood samples from 51 men with PC and 19 men with benign disease. Among the PC patients, 10 had organ-confined disease (pT1-pT2). We used a multiplexed reverse transcription-PCR assay with two highly target-like mRNA internal standards for the simultaneous quantification of PSA and hK2 mRNA. An external calibration curve covered the range of 10(2)-10(6) mRNA copies. Results: PSA and hK2 mRNA were detected in 41 of 51 (median, 1200 copies/0.5 mL of blood) and 43 of 51 (median, 3800 copies/0.5 mL of blood) patients with PC, respectively, whereas only 1 of 19 men with benign disease was positive for both mRNAs (1500 PSA and 3100 hK2 mRNA copies/0.5 mL of blood; P < 0.0001, Mann-Whitney U-test). Of the 10 patients with organ-confined PC, only 3 with low Gleason scores (less than or equal to5) were negative for both PSA and hK2 (P = 0.02, Mann-Whitney U-test). Conclusions: The presence of PC cells in the blood circulation is an early event in PC progression, and quantitative assays for PSA and hK2 mRNA discriminate benign from PC cases. Further studies are needed to determine the diagnostic accuracy and prognostic value of the assays.
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| 3. |
- Niemela, P, et al.
(författare)
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Sensitive and specific enzymatic assay for the determination of precursor forms of prostate-specific antigen after an activation step
- 2002
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Ingår i: Clinical Chemistry. - 0009-9147. ; 48:8, s. 1257-1264
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Tidskriftsartikel (refereegranskat)abstract
- Background: The proteome of the serine protease prostate-specific antigen (PSA) and its enzymatic properties have been clarified only recently. We have developed a specific and sensitive method for the measurement of active PSA and used it to measure proPSA in blood. Methods: We used the synthetic peptide KGISSQY, which possesses a PSA-specific cleavage site, as substrate. To ascertain the specificity of the assay, we used an anti-PSA monoclonal antibody that captures known forms of PSA. An activation step enabled us to measure proPSA by converting it to mature, active PSA. Results: The detection limit of the optimized assay was 0.5 mug/L. In blood samples from patients, the activation step substantially increased the concentration of active PSA, thus showing the presence of proPSA in the samples. ProPSA was 0-79% (median, 45%) of the amount of free PSA in 15 samples with total PSA concentrations of 5.3-423 mug/L. In samples obtained from three benign prostatic hyperplasia (BPH) patients after transurethal resection of the prostate, no significant increase in activity was detected after the activation step, thus showing that proPSA was not a portion of free PSA in plasma of BPH patients. Conclusions: Proforms of PSA are a considerable fraction of free PSA in the blood of patients with increased total PSA. The approach described can be used to study the diagnostic value of proPSA and active PSA in patients with BPH and prostate cancer.
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