| 1. |
- Christensson, A, et al.
(författare)
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Serum prostate specific antigen complexed to alpha 1-antichymotrypsin as an indicator of prostate cancer
- 1993
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Ingår i: Journal of Urology. - 1527-3792. ; 150:1, s. 100-105
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Tidskriftsartikel (refereegranskat)abstract
- Prostate specific antigen (PSA) in serum has recently been shown to occur in complex with alpha 1-antichymotrypsin and as an approximately 30 kDa. noncomplexed molecular form. We characterized PSA by 3 different assays in samples from 144 patients with benign prostatic hyperplasia (BPH) and 121 with carcinoma of the prostate. One of these noncompetitive assays measured total PSA by detecting PSA complexed to serine proteinase inhibitors and the noncomplexed molecular form, a second measured only PSA in complex with alpha 1-antichymotrypsin, whereas a third detected the noncomplexed form. PSA in complex with alpha 1-antichymotrypsin was the predominant form in all patient sera. Noncomplexed PSA constituted a minor fraction that was significantly smaller in patients with untreated prostate cancer than in those with BPH (p < 0.0001). The proportion of noncomplexed PSA does not correlate to the serum concentration of PSA or that of alpha 1-antichymotrypsin. In men with a serum PSA concentration of less than 10 micrograms./l. the combination of assays measuring total PSA immunoreactivity, the noncomplexed molecular form and PSA in complex with alpha 1-antichymotrypsin may facilitate discrimination between prostate cancer and BPH.
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| 2. |
- Lilja, H, et al.
(författare)
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Prostate-specific antigen in serum occurs predominantly in complex with alpha 1-antichymotrypsin
- 1991
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 37:9, s. 25-1618
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Tidskriftsartikel (refereegranskat)abstract
- Immunologic measurements of the serum concentration of prostate-specific antigen (PSA), an abundant prostatic-secreted serine proteinase, are frequently used to monitor patients with prostate cancer, though it has not been ascertained whether this immunoreactivity represents a PSA zymogen, the active proteinase, or PSA complexed to extracellular proteinase inhibitors. To characterize the PSA immunoreactivity in serum, we used monoclonal antibodies produced against PSA and a polyclonal rabbit IgG against alpha 1-antichymotrypsin in the design of three noncompetitive PSA assays: assay T, which detected PSA both when present as the active proteinase and when complexed to alpha 1-antichymotrypsin; assay F, which recognized the active proteinase but most poorly detected PSA complexed to alpha 1-antichymotrypsin; and assay C, which was specific for PSA complexed to alpha 1-antichymotrypsin. We used the three assays to measure PSA immunoreactivity in 64 patients' sera and in the effluent after gel chromatography of sera from four patients. This identified an 80- to 90-kDa complex between PSA and alpha 1-antichymotrypsin as the predominant fraction of the PSA immunoreactivity in blood plasma; an immunoreactive 25- to 40-kDa compound was the minor fraction.
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| 3. |
- Andersson, Mats, et al.
(författare)
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Simulated design and manufacturing of a circular press joint
- 1994
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Ingår i: Journal of Design and Manufacturing. - 0962-4694. ; 4, s. 245-252
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Tidskriftsartikel (refereegranskat)abstract
- Interest in using the press-joining method for joining of thin sheets has increased during recent year, especially in the car industry. This is mostly a result of the economic advantages and the ability to join coated or unweldable sheets. With increased knowledge about those parameters that affect the press-joining process, the possibility of reducing or avoiding unwanted deviations in production is improving. In this paper the finite clement method is used to analyze circular press joint. Though some of the results are only partially complete, they are very promising and can be a basis for further work. The analysis shows that it is possible to use the finite element method to simulate the press-joining process. Reasonable computation time is achieved by using a FE solver with an explicit iteration technique. The influences of material, tool conditioning and friction are discussed in the paper.
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| 4. |
- Lilja, Hans, et al.
(författare)
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Prostate specific antigen predominantly forms a complex with alpha1‐antichymotrypsin in blood. Implications for procedures to measure prostate specific antigen in serum
- 1992
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Ingår i: Cancer. - 0008-543X. ; 70:S1, s. 230-234
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Tidskriftsartikel (refereegranskat)abstract
- Background. Prostate specific antigen (PSA) is a zymogen of a 33‐kilodalton (kD) serine proteinase with extensive similarity to glandular kallikreins. The mechanism responsible for converting the zymogen into active proteinase has not been defined, but active PSA may be irreversibly inactivated in vitro by two of the major proteinase inhibitors in blood: alpha1‐antichymotrypsin and alpha2‐macroglobulin. Methods. Procedures have been designed to characterize the different molecular forms of PSA in serum. One assay detects PSA epitopes available on both PSA binding to serine proteinase inhibitors and PSA not binding to a proteinase inhibitor. A second assay only detects PSA in complex with alpha1‐antichymotrypsin. A third assay mainly detects PSA not binding to a proteinase inhibitor. Results. In serum samples, an 80‐kD to 90‐kD species of PSA in complex with alpha1‐antichymotrypsin is the predominant molecular form and a minor molecular form of serum PSA was an approximately 30‐kD fraction not binding to a proteinase inhibitor. Conclusions. The benefits of detecting different molecular forms of serum PSA should be investigated regarding possibilities to facilitate differential diagnosis of carcinoma of the prostate (CAP) and benign prostatic hyperplasia (BPH).
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| 5. |
- Stamey, T. A., et al.
(författare)
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Tumor markers. Consensus Conference on Diagnosis and Prognostic Parameters in Localized Prostate Cancer. Stockholm, Sweden, May 12-13, 1993
- 1994
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Ingår i: Scandinavian Journal of Urology and Nephrology, Supplement. - 0300-8886. ; :162, s. 73-87
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Tidskriftsartikel (refereegranskat)abstract
- This chapter mainly deals with biochemical aspects on prostate specific antigen (PSA) and its clinical value. To a limited extent, also other tumor markers, which might be of importance in the evaluation of patients with prostate cancer are discussed. In serum, PSA exists in a free form or bound to antichymotrypsin. Interestingly, only 10% of PSA secreted from cancer cells seems to exist in a free form, as compared to 30% of PSA secreted from cells in benign prostatic hyperplasia (BPH). PSA seems to be closely, but not absolutely, related to tumor grade and stage. The mean value of PSA in patients with tumors dominated by Gleason grades 3 or below, was 10 ng/ml, compared to 29 ng/ml in those with higher grades. Patients with PSA values of 50 ng/ml or above almost exclusively had tumor of Gleason grades 4 or 5, and this limit usually reflected a generalized disease. Patients with PSA-values below 10 ng/ml almost exclusively had tumors confined to the prostate gland. In countries where screening for prostate cancer is believed in, it is important to understand that normal cut-off values are related to patient's age. The upper normal limit of males below 50 years of age should be set at 2.5 ng/ml, as compared to 6.5 ng/ml for men over 70 years of age. To improve the value of PSA determination and for scientific purposes, the standardization of the assay is urgently needed and under way. Prostate acid phosphatase (PAP) has in most centres been replaced by PSA. An elevated PAP value, as measured by the enzymatic method, invariably indicates a generalized disease and could thus be used as a complementary informative assay to PSA. Other markers have been used mainly to achieve additional prognostic information. In a multivariate analysis, the non-specific tumor marker neopterin, which reflects the host response to tumor antigens, was closely related to short-term prognosis. Neopterin was followed by thymidine kinase, a protein reflecting the cell turn-over and tumor grade. Also PSA at diagnosis seemed to add some prognostic information, whereas other markers did not.
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