Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated a new fully automated procedure for quantitative measurement of prostate-specific antigen (PSA) by the Microparticle Enzyme Immunoassay (MEIA) technology developed for the Abbott IMx automated immunoassay system. The performance characteristics of the Abbott IMx PSA assay (y) were evaluated and compared with those of the Hybritech Tandem-E PSA assay (x), a solid-phase two-site immunoenzymometric assay. PSA values for both assays were well correlated (r = 0.99); regression analysis yielded the equation y = 0.92x - 0.23 micrograms/L. The Abbott assay proved reliable and reproducible, as shown by the intra- and interassay coefficients of variation (2.0-3.4% and 3.1-4.7%, respectively). The assay gave a linear standard curve up to 100 micrograms/L and was very sensitive (detected PSA < 0.1 microgram/L). This analytical sensitivity was comparable with that of the Tandem-E PSA assay. Overall, the IMx PSA assay demonstrated the accuracy, precision, linearity, and intermethod correlation required for monitoring patients with prostate cancer.
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PMID:Abbott IMx evaluated for assay of prostate-specific antigen in serum. 138 93

Prostate specific acid phosphatase (PAP) (Abbott, solid-phase enzyme immunoassay) and prostate specific antigen (PSA) (Hybritech, immunoradiometric assay) were determined in 162 newly diagnosed prostatic carcinoma patients, 187 patients with benign prostatic hyperplasia (BPH) and 127 controls. The upper limit of normal in controls for PAP was 2.2 micrograms/l and for PSA 5.0 micrograms/l. In the BPH group PAP was raised in 21%, for PSA in 41%. When the cut-off level of PSA was raised to 10.0 micrograms/l, 20% of BPH patients had an increased level. PSA was superior to PAP for the detection of prostatic cancer in all stages. Of the 162 patients with prostatic carcinoma, 88 had localised diseases and 74 had metastatic spread. PSA and PAP levels increased with each advancing clinical stage. PAP was elevated in 35% of the patients with cancer confined to the prostate. PSA in 69%. (PSA level 10.0 micrograms/l: 57%). In those patients with metastatic spread PAP was elevated in 77% compared with 96% for PSA. (PSA level 10.0 micrograms/l: 92%). The combined use of PSA and PAP does not give a greater accuracy in the screening of prostate cancer when compared with the sole use of PSA. PAP was elevated in only 4 patients when PSA was normal. In the BPH group there was no proven effect of micturition, frequency or residual urine on the SPA level. However, in this group infection may cause a rise in the PSA level.
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PMID:Evaluation of prostate-specific antigen and prostatic acid phosphatase in untreated prostatic carcinoma and benign prostatic hyperplasia. 172 15

Immunohistochemical investigations of human prostate and human prostate cancer were performed using two different monoclonal antibodies for the demonstration of estrogen receptors (ER). One marked the nuclear estrogen receptor protein (ERICAR, Abbott Laboratories), whereas the other one marked an estrogen receptor-associated cytoplasmic protein (ER-D5 kit, Amersham Buchler). 12 transurethral resection specimens with benign prostatic hyperplasia and 10 prostatic carcinomas were investigated by ERICA. Only in 1 specimen was a focally ERICA-positive basal cell hyperplasia found. The ER-D5 kit yielded a constantly positive reaction of stromal cells, especially smooth muscle cells. Basal cell hyperplasia and squamous metaplasia, alterations which can occur during estrogen application, were always strongly ER-D5-positive. Eleven (13.4%) out of 82 prostate carcinomas were focally positive. The staining results with ER-D5 are in good accordance with biochemical estrogen receptor investigations which demonstrated the estrogen receptors especially in the fibromuscular stroma. Furthermore, the results show that therapeutically applied estrogens do not directly inhibit the growth of prostatic carcinoma, however, the effect is an indirect one by suppressing androgen synthesis of the testis. The different staining results with ER-D5 and ERICA can be explained by the low ER concentration of prostate, the concentration is evidently below the limits of detectability with ERICA.
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PMID:Immunohistochemical estrogen receptor demonstration in the prostate and prostate cancer. 343 7

Prostate-specific antigen (PSA) in serum is primarily complexed with alpha 1-antichymotrypsin (alpha 1-ACT). However, 12-15% of prostate cancer (PCa) patients present with the predominant form being uncomplexed (free) PSA (Lilja et al., Clin Chem 1991;37:1618-24). We report that commercial immunoassays demonstrate variations in reactivity, especially to the uncomplexed form. We fractionated and analyzed commercial controls, PSA complexes prepared in vitro, and sera from patients with PCa or benign prostatic hyperplasia, using molecular sieve chromatography and Hybritech Tandem-R, Abbott IMx, and Ciba Corning ACS PSA assays. Peak integration of PCa samples demonstrated ACS:Tandem-R ratios of 1-1.3 for PSA/alpha 1-ACT complex. In contrast, ratios of uncomplexed peaks ranged from 2 to 4, suggesting a greater reactivity of the uncomplexed form in the ACS PSA assay. Discrepancies between assays, when PSA was measured in unfractionated sera, correlated directly with the percentage of the uncomplexed form. In controls, fractionation revealed the presence of uncomplexed PSA only, with ratios of ACS:Tandem-R and IMx:Tandem-R of 3:1 and 1.8:1, respectively. Immunoblots of PCa sera detected uncomplexed PSA (approximately 30 kDa) and PSA complexes of approximately 95 kDa (PSA/alpha 1-ACT) and > 200 kDa, indicative of alpha 2-macroglobulin. Maximal recognition of all forms of PSA may be important for early detection of disease progression.
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PMID:Multiple forms of prostate-specific antigen in serum: differences in immunorecognition by monoclonal and polyclonal assays. 752 44

This paper summarises the results of a comparison of the Serono SR1, Ciba Corning ACS 180, Abbott IMx and Hybritech Tandem-R prostate-specific antigen assays. One hundred serum pools were assayed using the four methods. Linear regression analysis of the data showed that, although overall correlations were good, different assays gave different prostate-specific antigen concentrations. Tandem-R and SR1 assays gave very similar prostate-specific antigen values; in general, the ACS assay gave higher prostate-specific antigen values than the IMx assay gave lower prostate-specific antigen values than the established Tandem-R assay. Following fractionation of serum from prostate cancer patients, all immunoassays detected several immunoreactive prostate-specific antigen forms. The major immunoreactive form (> 88% of immunoreactivity) had an apparent molecular size of M(r) approximately 100,000 and is likely to be a complex of prostate-specific antigen with alpha 1-antichymotrypsin; two minor forms had apparent molecular sizes of M(r) approximately 30,000 (probably free prostate-specific antigen) and 200,000 (probably prostate-specific antigen complexed to high molecular mass anti-proteases). From this study there is no evidence that polyclonal/monoclonal antibody immunoassays are to be preferred to monoclonal/monoclonal antibody immunoassays for the determination of free prostate-specific antigen in serum.
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PMID:Measurement of prostate-specific antigen in serum using four different immunoassays. 751 58

We examined by gel filtration chromatography (Sephacryl 200) sera from 73 untreated patients with peripheral zone prostatic cancer volumes of 1 to 17 cc as well as patients with clinical stages C and D2 cancer. We also examined the sera from 40 patients who had failed radiation or hormonal therapy to determine if clonal cell selection by these 2 therapies altered the binding of prostate specific antigen (PSA) to alpha 1-antichymotrypsin. Finally, we compared sera from 10 patients with benign prostatic hyperplasia (BPH) and 14 with large transition zone-BPH cancer. Without exception, of the total serum PSA recognized by the Hybritech Tandem-R, Yang Pros-Check, Abbott IMx and Ciba Corning ACS assays, 88 to 98% were complexed with alpha 1-antichymotrypsin in all cancer patients. The 10 patients with BPH showed less complexation (73 to 84%). These studies suggest that much of the quantitative differences among assays is determined more by relative differences in recognition of the free and complex forms of PSA than by calibration differences between assays.
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PMID:Serum prostate specific antigen binding alpha 1-antichymotrypsin: influence of cancer volume, location and therapeutic selection of resistant clones. 752 8

Consistency and reproducibility of serum prostate-specific antigen (PSA) measurement are essential in the application of this analyte to early detection or screening programs. In the present investigation, we sought to compare serum PSA levels determined by the IMx assay (Abbott Laboratories, North Chicago, IL) and the Tandem E (Hybritech Inc., San Diego, CA) to determine whether there were differences. Two hundred twenty-eight random sera from our archival bank were investigated. One hundred-eight specimens were in the Tandem range of 2.0-10.0 ng/ml, and prostatic histology was known based on either systematic sector needle biopsy or transurethral resection. PSA was measured with three different lost of the IMx and Tandem assays. Over the entire range, there was a good correlation (r2 = 0.985); however, in the more useful clinical range of 2.0-10.0 ng/ml, the correlation was reduced to 0.923; in the 2.0-6.0 ng/ml range, it was further reduced to 0.852. The slope for the entire range was 0.948; however, in the 2.0- to 10.0-ng/ml range, it was 0.894; in the 2.0- to 6.0-ng/ml range, the slope was 0.815. Using PSA cutoffs of 4.0, 5.0, and 6.0 ng/ml, significant decrease in abnormal PSA values in men with cancer was observed with the IMx compared with Tandem. These data suggest that the IMx and the Tandem PSA assays are not equivalent, and in most patients a lower value is realized with the IMx assay. This bias appears to be greater in men with prostate cancer. Clinicians must be aware which assay their patients are being tested with, and laboratory technicians should run internal standards to ensure lack of significant intralot variability and consistency over time.
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PMID:Assay variability in serum prostate-specific antigen determination. 754 27

Hoffmann-La Roche has introduced a fully automated COBAS CORE EIA for the measurement of prostate specific antigen (PSA). A regular and an ultrasensitive version of the assay are available. Both versions of the COBAS CORE PSA EIA were compared with the established IMx PSA assay from Abbott. Sera from 98 apparently healthy males, 224 patients with benign prostate hyperplasia, 17 patients with prostatitis and 111 patients with prostate cancer were determined using the COBAS CORE PSA EIA in comparison with the IMx PSA assay. The sera were drawn before treatment. Sera from 26 patients were also monitored through follow-up testing. The COBAS CORE analyser allows rapid analysis of large series of samples. Intra-assay imprecision (CV) was between 1.7% and 4.9% (IMx PSA: between 2.4% and 2.7%). The coefficient of variation for inter-assay imprecision was between 3.4% and 6.5% (IMx PSA: between 3.2% and 3.3%). The analytical detection limit was determined as 0.2 microgram/l for the regular COBAS CORE PSA EIA and 0.05 microgram/l for the ultrasensitive version. A biological detection limit of 0.1 microgram/l was determined for the ultrasensitive version. Results obtained using the COBAS CORE PSA EIA and IMx PSA assays were in excellent correlation: coefficient of correlation r = 0.99 and slope = 0.92, using prostate-specific antigen values from the complete study. Only in the measuring range below 10 micrograms/l did the coefficients of correlation vary between 0.82 and 0.93.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of the COBAS CORE Immunoassay for measuring prostate-specific antigen (PSA)--multi-centre study results. The PSA Study Group. 854 40

An immunoassay's minimal detectable concentration (MDC), the smallest analyte concentration the assay can reliably measure, is one of its most important properties. Bayes' theorem is used to unify the five current mathematical MDC definitions. The unified definition has significant implications for defining positive results for screening and diagnostic tests, setting criteria for immunoassay quality control and optimal design, reliably measuring biological substances at low concentrations, and, in general, measuring small analyte concentrations with calibrated analytic methods. As an illustration, we apply the unified definition to the microparticle capture enzyme immunoassay for prostate-specific antigen (PSA) developed for the Abbott IMx automated immunoassay system. The MDC of this assay as estimated by our unifying approach is shown to be 4.1-7.1 times greater than currently reported. As a consequence, the ability of the assay to measure reliably small concentrations of PSA to detect early recurrences of prostate cancer is probably overstated.
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PMID:Defining the smallest analyte concentration an immunoassay can measure. 934 36

In this study, various analytical aspects of the determination of serum prostate-specific antigen are described as applied to the Abbott IMx PSA and the Hybritech Tandem-E PSA assays. We used mainly specimens from a prostate cancer screening study in progress. A very good comparability between the assays proved to exist in our hands. The long-run variation (16 months) was also rated as acceptable, both for the IMx and the Tandem-E method. The method of choice, Tandem-E, showed good reagent stability over this period. We found, however, a difference in accuracy (Tandem-E +/- 8% higher values) that could not be explained by comparison with Tandem-R.
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PMID:Some analytical considerations on the measurement of prostate-specific antigen. 893 5


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