Total PSA

Calculation of the percentage of free PSA compared with the total PSA ... 

Factors such as assay variations, age, and prostate gland size are known to affect cutoff values. Also, free to total PSA cutoffs are influenced by the sensitivity and specificity values chosen, the reflex range for total PSA used, differences in free PSA assays, and differences in populations studied. Different PSA values are considered due to differences in cutoffs in different assays. Studies have shown that the comparison of a chemiluminescent free PSA showed a 25 percent difference in values. These types of variations suggest a need for standardization (9,29). 

Junker, R., Brandt, B Zechel, C Assmann, G. Comparison of prostate-specific antigen (PSA) measured by four combinations of free PSA and total PSA assays. Clin. Chem. 43, 1588-1594... 

Eu3+, Tb3+, Sm3+, Dy3+ complexes have different emission wavelengths with sharp peak profiles, which are suitable for multi-component immunoassay. Several Eu-Sm two-color time-resolved immunoassays have been reported. Since the sensitivity of Sm3+ chelates is not high compared to Eu3+ and Tb3+, Eu-Sm two-color assays are used for the simultaneous determination of a low concentration component (Eu) and a relatively high concentration component (Sm) in serum the assayed combinations are lutropin and follitropin, myoglobin and carbonic dehydratase, AFP and free (3-subunit of human chorionic gonadotrophin (Hemmila et al., 1987). Use of Eu-Tb is reported by Eriksson et al. (2000) for the simultaneous determination of human serum free and total PSA. 

Ito K, Yamamoto T, Ohi M, Kurokawa K, Suzuki K, Yamanaka H, Free/total PSA ratio is a powerful predictor of future prostate cancer morbidity in men with initial PSA levels of 4.1 to lO.Ong/mL. Urology, 61 760-764, 2003. 

Prostate specific antigen (PSA) is a reliable clinical tool for diagnosing and monitoring prostate cancer. Sarkar et al. [83] developed an ampero-metric detection procedure for detecting total PSA in human serum using... 

NACB, National Academy of Clinical Biodiemistry ASCO, American Society of Clinical Oncology ACS, American Cancer Society EGTM, European Group on Tumor Markers tPSA, total PSA fPSA, free PSA NSGCT, nonseminomatous germ cell tumors,... 

The metabolic clearance rate of PSA follows a two-compartment model with initial half-lives of 1.2 and 0.75 hours for free PSA and total PSA and subsequent half-lives of 22 and 33 hours. Because of this relatively long half-life, 2 to 3 weeks may be necessary for the serum PSA to return to baseline levels after certain procedures, including transrectal biopsy, transrectal ultrasonography, transurethral resection of the prostate, and radical prostatectomy. Prostatitis and acute urinary retention can also elevate PSA concentration. Although the digital rectal examination has no clinically important effects on serum PSA levels in most patients, in some it may lead to a twofold elevation. 

The ProstAsure index, developed by Zhang, Stamey, and Chan, was designed to increase the sensitivity and specificity of cancer detection, while maintaining a reasonable false positive detection rate. The index is derived firom several values, including age, total PSA, creatine kinase isoenzymes, and prostatic acid phosphatase, which are input... 

Immunohistochemical studies demonstrated that tissue expression of hK2 showed intense staining in high-grade cancers and lymph node metastases, whereas it showed weaker staining for low-grade cancers and BPH. Serum hK2 alone or hK2 total PSA/free PSA has been shown to be... 

Haese A, Graefen M, Steuber T, et al. Human glandular kallikrein 2 levels in serum for discrimination of pathologically organ-confined from locally-advanced prostate cancer in total PSA-levels below lOng/ml. Prostate 2001 49 101. 

Partin AW, Catalona WJ, Southwick PC, et al. Analysis of percent free prostate specific antigen (PSA) for prostate cancer detection Influence of total PSA, prostate volume and age. Urology 1996 48 55-61. 

Partin AW, Piantadosi S, Subong ENP, et al. Clearance rate of serum free and total PSA following radical retropubic prostatectomy. Prostate Supp 1996 7 35-39. 

Pearson JD, Uderer AA, Metter EJ, et al. Longitudinal analysis of serial measurements of fi ee and total PSA among men with and without prostatic cancer. Urology 1996 48 4-9,... 

SokoU LJ, Chan DW, Mikolajczyk SD, et al Proenzyme PSA for the early detection of prostate dancer in the 2.5-4.0ng/mL total PSA range Preliminary analysis. Urology 2003 1 274-76. 

PSA is one of the most widely used cancer biomarkers. It is a chymotryp-sin-like serine protease that is produced by epithelial cells of the prostate gland and secreted into the prostatic fluid. Prostate-cancer invasion disrupts the epithelial membrane barrier leading to elevated serum levels of PSA. Detection of PSA in blood can therefore be useful in the diagnosis of prostate abnormalities and for evaluation of prostate cancer therapy efficacy [21]. Two different forms of PSA are immunologically detectable the free form (MW 34 kDa) and a complex with a-l-antichymotrypsin (MW 96 kDa). Diagnostic assays developed for detection of PSA (e.g., enzyme-linked immunosorbent assays) detect total PSA concentrations down to 0.1 ngmL [22,23]. 

Zhu L, Leinonen J, Zhang WM, Fiime P, Stenman UH (2003) Dual-label immunoassay for simultaneous measurement of prostate-specific antigen (PSA)-alphal-antichymotrypsin complex together with free or total PSA. Clin Chem 49 97-103... 

Dual-label TR-FRET substrates have also been used for simultaneous monitoring of the enzymes related to apoptosis caspases 1, 3, and 6 [44]. Kokko et al. utilized fluorescent terbium chelates as the donors for two different acceptors, Alexa Fluor 488 and 680, in a dual-label immtmoassay of free and total PSA [45]. Free, uncomplexed PSA were measured with TR-FRET from terbium labeled (universal) antibody to free-specific Alexa 488 labeled antibody, and the total PSA was quantified with TR-FRET from terbium to another generic antibody labeled with Alexa 680. Kupcho et al. followed nuclear receptor coactivator recruitment... 

Jaras K, Adler B, Tojo A, Mahn J, Marko-Varga G, Lilja H, Laurell T (2012) Porous silicon antibody microarrays for quantitative analysis measurement of free and total PSA in clinical plasma samples. Chn Chim Acta 414 76-84... 

Of the three major classes of polymers in use today, acrylics make up the largest volume of material at 33% of the total PSA market. Synthetic block-copolymer elastomer represents 25% of the total PSA market. Since these are almost imi-versally compounded with tackifying resins, the amount of PSA produced using block copolymers could be twice as large as the amoimt of elastomer used. Natural rubber represents 22% of the total PSA market, but is also compounded with resin to produce a PSA, and so the total amoimt of PSA produced is also larger (45). This represents a shift toward acrylics from 10 years ago when the relative... 

The total PSA research efforts in Sweden lately have been concentrated to the procedures related to analysis of external events, since it has been found out that the contribution from external initiating events could be up to 50% to the total core damage frequency. External event analyses have been proven useful and have resulted in several important plant modifications that have increased safety. 

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