Prostate Specific Antigen Kit Research Articles

Nonlinear hybridization chain reaction-based flow cytometric immunoassay for the detection of prostate specific antigen

Sensitive detection of biomarkers is highly desirable for disease diagnosis and postoperative examination. As a signal amplification technique, nonlinear hybridization chain reactions (NHCR) based on DNA self-assembly has been widely adopted to versatile biosensor platforms for signal output and sensitivity enhancement. Herein, we proposed a novel hairpin-free NHCR based flow cytometric immunoassay for prostate specific antigen (PSA) detection. In this study, Ab1-Ag-Ab2-streptavidin-trigger DNA complexes were formed on the magnetic beads (MBs), and each trigger DNA initiated a round of NHCR amplification to form dendritic DNA nanostructures with many fluorescent signal molecules. The robust flow cytometric fluorescent analysis was finally employed for the quantitation of target protein on the MBs. As far as we know, this is the first time to combine the hairpin-free NHCR strategy with fluorescent immunoassay on MBs to detect protein biomarkers. In addition to the high selectivity of immunoassay itself, the characteristics of isothermal, enzyme-free, and exponential amplification efficiency of hairpin-free NHCR endow this developed immunoassay with a detection limit that exceeds 100-folds that of commercially available PSA kits. Moreover, this MBs-based platform of this immunoassay is also amenable to target enrichment and removal of spontaneous NHCR signal through magnetic separation, greatly eliminating the background signal interference. With our efforts, this newly developed biosensor exhibits a detection limit of 1.92 pg/mL and shows high selectivity. It has also been successfully applied to the quantitative detection of PSA in serum samples. With these merits, this convenient biosensor platform has the potential for medical research and disease diagnosis.

Effect of Colonoscopy on Prostate-Specific Antigen; New Words about an Old Subject

Prostate Specific Antigen (PSA) is a protein currently used in conjunction with the digital rectal examination to detect and guide management of prostate cancer. There are several causes of increase in serum PSA including urological manipulations, medications, prostatic diseases, prostate cancer, prostate inflammation or infection, etc. some studies had reported cystoscopy to cause transient increases in PSA. The present study has been undertaken with an aim to find out the effect of rigid cystoscopy on serum PSA level. Methods: One hundred two men referring to clinic of urology of Imam Reza Hospital from 2008 to 2010 were included in this study. Their age ranged from 31-88 years with the mean of 65.85 years. Our inclusion criteria were having an indication for cystoscopy like BPH, erection disorder, signs related to prostate or bladder carcinoma. Patients with positive urine culture, any medication affecting PSA level, history of urinary retention, any urological manipulations a few days before and ejaculation 48-72 hours before PSA assessment were excluded from the study. Blood samples were taken before and 24 hours after cystoscopy for PSA measurement. PSA was measured by Sandwich ELISA test using PSA kit (pishtaz kit - made in Iran) containing monoclonal antibody. Results: PSA level of the study cases varied from 0.1 to 21 ng/ml. Mean PSA values before and after cystoscopy were 3.004± 3.34 and 2.92 ± 2.98 respectively indicating that after cystoscopy not only PSA value did not raise but also decreased to some extent. Conclusion: Our findings indicate that, cystoscopy has no effect on PSA value and does not lead to its elevation. It can be concluded that serum PSA after rigid cystoscopy is an accurate and reliable finding to decide about patients condition related to prostate cancer.

Prostate Specific Antigen (PSA) Screening among Apparently Healthy Men of African Descent in Sokoto, North Western, Nigeria

Background: Globally prostate cancer is the sixth leading cause of cancer-related death in men. Prostate Specific Antigen (PSA) is present in small amount in the serum of men with healthy prostates, but is often elevated in the presence of prostate cancer and other prostate-related disorders. The aim of this present study was to determine the PSA levels among healthy men of African descent resident in Sokoto, North Western Nigeria. Methods: Testing was carried out using the CTK Biotech PSA kit (CTK Biotech Inc, San Diego, USA). The Onsite PSA Rapid Test is a lateral flow chromatographic immunoassay for the qualitative detection of prostate specific antigen (PSA) in human serum or plasma at a cut-off level of 4.0 ng/mL. Original Research article

Evaluation of semen presumptive tests for use at crime scenes

The SERATEC PSA Semiquant and RSID-Semen tests are immunoassay kits that identify semen by detecting prostate-specific antigen (PSA) and semenogelin (Sg), respectively. Both kits were tested with semen, urine, blood, saliva, vaginal secretions and breast milk in order to determine their sensitivity and specificity. These results demonstrate that the SERATEC PSA kit is more sensitive than the RSID-Semen kit with a limit of detection of 200 ng/mL as opposed to 8.0 x 10(3) ng/mL. The RSID-Semen kit gave no false-positives or -negatives compared with 2.9% false-negatives with the SERATEC PSA kit. Results from postcoital samples show the RSID-Semen kit to be more effective, indicating that this kit is more suitable for semen identification in the Haven Suites. As a more robust and cost-effective kit, the SERATEC PSA test is recommended for use at crime scenes. The ability to obtain DNA profiles from the buffer of both kits demonstrates the potential benefit of these kits in a rape investigation. The use of these kits at crime scenes would provide an invaluable contribution by prioritizing samples for subsequent analysis, thereby allowing greater efficiency with investigation times.

The ratio of prostate‐specific antigen (PSA) to prostate volume (PSA density) as a parameter to improve the detection of prostate carcinoma in PSA values in the range of < 4 ng/mL

The objective of this study was to evaluate the prostate specific antigen (PSA) density (PSAD) (the quotient of PSA and prostate volume) compared with the percent free PSA (%fPSA) in different total PSA (tPSA) ranges from 2 ng/mL to 20 ng/mL. Possible cut-off levels depending on the tPSA should be established. In total, 1809 men with no pretreatment of the prostate were enrolled between 1996 and 2004. Total and free PSA were measured with the IMMULITE PSA and Free PSA kits (Diagnostic Products, Los Angeles, CA). Prostate volume was determined by transrectal ultrasound. The diagnostic validity of tPSA, %fPSA, and PSAD was evaluated by receiver operation characteristic (ROC) curve analysis. The PSAD differed significantly (P < 0.0001) between patients with prostate carcinoma and patients with benign prostatic hyperplasia in all analyzed ranges of tPSA and prostate volume. At the 90% and 95% sensitivity levels and regarding the area under the ROC curve (AUC) within the tPSA range of 2-4 ng/mL, The PSAD was significantly better than tPSA and %fPSA. Within the tPSA range of 4-10 ng/mL, the PSAD did not perform better than %fPSA. PSAD showed a better performance than %fPSA at tPSA concentrations < 4 ng/mL for detecting prostate carcinoma, with a significantly larger AUC for PSAD (0.739) compared with %fPSA (0.667). PSAD did not perform better than %fPSA when the tPSA range of 4-10 ng/mL was analyzed. Different PSAD cut-off values of 0.05 at tPSA 2-4 ng/mL, 0.1 at tPSA 4-10 ng/mL, and 0.19 at 10-20 ng/mL were necessary to reach 95% sensitivity.

Determination of the relative probability for prostate cancer to avoid unnecessary biopsy

To investigate whether using a new concept of relative probability for prostate cancer (RPpca) can increase sensitivity and specificity in detecting prostate cancer. For 217 patients with total prostate-specific antigen (PSA) level of 4-20 ng/mL, prostate volume and free to total PSA (F/T) ratio were measured. From the fitted curves between positive predictive values for prostate cancer and age, prostate volume, total PSA or the F/T ratio, each function predicting prostate cancer was determined. RPpca defined by the combined functions of age, prostate volume, total PSA and F/T ratio was calculated for each individual patient. The probability of prostate cancer was also calculated, using logistic regression analysis (LRPpca). Receiver-operating characteristic analysis was performed to elucidate the areas under the curve (AUC), sensitivities and specificities and cutoff values of the conventional and new parameters. Finally, we investigated the applicability of the above parameters in the other patient group using a different PSA assay kit (AxSYM). Although RPpca had the largest AUC in the total PSA range of 4-20 ng/mL, it did not reach statistical significance between RPpca and F/T ratio or LRPpca. The cutoff values of F/T ratio, LRPpca and RPpca were determined as 0.15, 0.12 and 0.20, respectively. Using these cutoff values in AxSYM data, RPpca had the highest sensitivity (91%) and specificity (57%). RPpca can provide more precise information to avoid unnecessary biopsy than LRPpca or F/T ratio. RPpca could be valuable to decide whether to perform prostate biopsy when using various PSA kits.

Clinical Usefulness of Serum Antip53 Antibodies for Prostate Cancer Detection:: A Comparative Study With Prostate Specific Antigen Parameters

Alterations in the p53 tumor suppressor gene located on human chromosome 17p13.1 are currently the most common genetic abnormalities associated with many different types of human malignancies. Recently serum p53 antibodies (p53-Abs) have been detected in the serum of patients with various cancers. To evaluate the clinical usefulness of serum p53-Abs we compared p53-Abs with prostate specific antigen (PSA) parameters in patients with benign prostatic disease (BPD) and prostate cancer. Serum samples were obtained from 50 patients with BPD and 103 with histologically diagnosed prostate cancer, including T1c/2N0M0 in 50, T3N0M0 in 29 and TxNxM1 in 24. The serum p53-Abs titer was assessed by enzyme-linked immunoabsorbent assay using a MESCUP Kit II (Medical and Biological Laboratories Co., Ltd., Nagoya, Japan) antip53 test. Free and total PSA was measured using an Architect (Dinabott, Chicago, Illinois) PSA kit. The clinical values of p53-Abs were compared with total PSA, PSA density (PSAD), PSA density of the transition zone (PSATZD) and the free-to-total PSA ratio using ROC curves. All patients with prostate cancer had significantly higher total PSA, PSAD, PSATZD and p53-Abs than patients with BPD. While total PSA, PSAD, PSATZD and free-to-total PSA ratios were associated with stage progression, serum p53-Abs were not related to clinical stage. The Gleason sum 5 or less group had a higher level of p53-Abs than higher Gleason sum groups. Patients with T1c cancer had significantly higher p53-Abs than those with BPD. According to ROC curve analysis to distinguish prostate cancer from BPD the p53-Abs titer had the greatest AUC in the overall patient population and in patients without digital rectal examination findings. These results suggest that p53-Abs might be helpful in the clinical decision to perform prostate biopsy. In the current study the serum p53-Abs titer had the most useful validity in discriminating between prostate cancer and BPD in the overall patient population and in patients with normal digital rectal examination.

Evaluation of prostate-specific antigen (PSA) membrane test for forensic examination of semen

Prostate-specific antigen (PSA) is a glycoprotein produced by the prostatic gland and functions to liquefy the seminal fluid. Recently several PSA membrane test kits utilizing an immunochromatographic assay are commercially available for clinical screening of PSA concentration in serum. In this study, we applied the three PSA test kits to forensic examination of semen, and evaluated the sensitivity and specificity of the PSA test kits. The specificity were the same, but SMITEST PSA Card had the highest sensitivity among the three kits. Furthermore we certified that the SMITEST PSA Card was little affected by heat or contaminants such as other body fluids, reagent of preliminary test for semen stain and spermicides, and the PSA kit was applied to 30 casework samples.

Evaluation of a rapid qualitative prostate specific antigen assay, the One Step PSATM test

Recently, highly sensitive prostate specific antigen (PSA) kits have been developed and reported to be useful for the early identification of a chemical relapse. However, if the measurement time was short and the cost low, such an assay kit should be sufficient for cancer screening when dealing with a large number of samples. The One Step PSA test uses an immunochromatographic method to qualitatively, not quantitatively, judge a positive or negative result. We confirmed the sensitivity of the kit using purified PSA. Serum specimens from 147 men with or without prostate diseases were tested using the kit. PSA concentration of each serum specimen was independently measured by a quantitative ACS-PSA2 EIA kit (Chiron, cut-off: 2.1 ng/ml).The sensitivity of this kit was determined to be 4 ng/ml. All 33 samples with a value of greater than 4 ng/ml were clearly positive. Of the 94 samples with values less than 4 ng/ml, nine were judged as positive. The remaining 85 cases were judged as completely negative. These results indicate that the sensitivity of the One Step PSA test is 100% and the specificity is 90.4%.Tests using this kit can be easily performed at outpatient clinics or elsewhere. This kit is useful for initial cancer screening, because results can be obtained within 15 min and at a cost lower than that of ordinary PSA kits.

Characterization of Monoclonal Antibodies for Prostate-specific Antigen and Development of Highly Sensitive Free Prostate-specific Antigen Assays

The recent elucidation of the importance of serological free prostate-specific antigen (PSA) in the diagnosis of prostate cancer has created a demand for immunoassays specific for free PSA. We developed and characterized 11 monoclonal antibodies with high affinities for PSA (Ka values from 1.1 x 10(8) to 1.8 x 10(10)L/mol), only 3 of which cross-react with human glandular kallikrein (hK2). Using these antibodies and PSA antibodies developed by others, in conjunction with time-resolved fluorometry, we developed ultrasensitive sandwich immunoassays specific for the free form of PSA. The analytical detection limit of these immunoassays is 0.001 microg/L. To our knowledge, this is the most sensitive free PSA assay reported to date. The free PSA immunoassays exhibit <1% cross-reactivity with PSA-alpha1-antichymotrypsin, show no cross-reactivity with hK2, and correlate well with established free PSA kits. The 11 antibodies developed by our group, in conjunction with 4 commercially available antibodies, were used to generate a putative epitope map of the PSA molecule. The highly sensitive free PSA immunoassays may be used for measuring PSA subfractions in female serum, an application currently impossible with other reported free PSA immunoassays.

Analytical performance of the Tandem®-R free PSA immunoassay measuring free prostate-specific antigen

The analytical performance of the Tandem-R free PSA assay available from Hybritech Inc. was evaluated. Comparison of recoveries of purified free (unbound) prostate-specific antigen (PSA) diluted in female serum in the Tandem-R free PSA assay and the Tandem-R (total) PSA assay demonstrated a link in calibration between the assays and an accurate determination of percent free PSA. The cross-reactivity of the assay to purified PSA-alpha 1-antichymotrypsin was determined to be < 1%. The minimum-detectable concentration was < 0.05 microgram/L. The within-run and between-day CVs were < or = 5% for samples with > 0.3 microgram/L free PSA. Dilution and recovery showed no significant deviations from linearity across the assay range. The assay was insensitive to interference from blood components. The Tandem-R free PSA kit was shown to be an accurate, precise, and reliable assay for the measurement of free PSA.

Prostate-specific antigen levels from a mass screening program using highly sensitive RIA kits.

This study was designed to evaluate the distribution of prostate-specific antigen (PSA) levels of men in a mass screening program for prostatic disease. A total of 763 men over 40 years of age underwent mass screening for prostatic disease in a Japanese prefecture using the highly sensitive Eiken kit and the Hybritech (Tandem-R) kit. The screening tests consisted of serum PSA determination, digital rectal examination, a questionnaire on symptoms, evaluation of prostate volume, and determination of the obesity rate. Serum PSA levels of all subjects were measured with both kits. The correlation between the values obtained by the Eiken kit and those of the Tandem-R kit was high (r = 0.990), but the values of the former were slightly higher than those of the latter. Serum PSA weakly correlated with age, however, when estimated within decade age brackets, the levels of PSA showed significant differences among only 1 pair of groups stratified by age. In contrast, the levels of PSA showed significant differences among 9 pairs of groups stratified by prostate volume. A highly sensitive assay kit is useful to evaluate both the distribution of PSA levels and the relationship of PSA values to age and prostate volume of men in mass screening programs for prostatic disease, since approximately 40% of the subjects who underwent the present mass screening showed PSA values under 1.0 ng/mL, which have been the the lower limit of detection of many PSA kits.

Improvement of prostate cancer screening by determination of the ratio free/total PSA in addition to PSA levels.

The measurement of prostate specific antigen (PSA) is widely used in screening programs for early detection of prostate cancer. However the specificity for cancer detection is limited because serum PSA is also elevated in patients with benign prostatic-hyperplasia (BPH) and/or prostatitis. It has been shown recently, that the ratio of free/total PSA in serum is lower in malignant prostatic disorders than in non-malignant ones and therefore might be a parameter to improve screening specificity. In a retrospective study, we tested whether free/total PSA helps to distinguish between BPH and prostatic carcinoma in men with elevated serum PSA. A total of 266 men have been identified with age-specific elevated serum PSA levels using a conventional PSA determination kit. Subsequently their disease was proven by biopsies. Free and total PSA levels in these serum samples were measured using the DELFIA PSA dual label free/total PSA kit. The mean free/total PSA of 64 patients with prostate cancer was 0.10 and was significantly (P = 0.001) different from the mean free/total PSA of 202 men who were histologically free of cancer, which was 0.17. Receiver-operating-characteristic curve (ROC) analysis showed that using a free/total PSA ratio of 0.18 as a biopsy criterion in men with an elevated PSA serum level, 37% of the negative biopsies could be eliminated while still detecting 94% of all carcinomas. These results show that the ratio of free/total PSA is a useful determination and can improve specificity of prostate cancer screening.

A pilot study of mass screening program for prostatic cancer by means of prostate specific antigen (PSA) filter paper method

Mass screening program for prostatic cancer (PC) using prostate specific antigen (PSA) filter paper method was performed in an urban area of Kyoto in 1995. In the primary study, males more than the age of 55 years were examined by PSA (Delfia PSA kit) with blood samples on a filter paper. The cut-off values were set at 4 and 10 ng/ ml. Subjects whose PSA level ranged from 4.1 to 10.0 ng/ml (gray zone) were examined by digital rectal examination (DRE), transrectal sonography (TRS) and PSA density (PSAD; more than 0.15) in the secondary study, then the suspected subjects of PC underwent 6 sextant biopsies under interventional ultrasound. Subjects whose PSA level were more than 10.1 ng/ml were biopsied directly. Of 3,749 males who took the annual health checkup system organized by the government, 2,387 males wished to submit this screening. Among them, 2,217 (92.9%) showed a negative PSA, 107 belonged to the gray zone and 43 had a PSA more than 10.1 ng/ml. Of these, 102 subjects underwent biopsy. PC was finally detected in 28 (1.2%). The positive predictive value for positive PSA and gray zone PSA was 46.3% and 8.4%, respectively. In the detected cancers, 17 cases (60.7%) belonged to Stage B, 5 (17.9%) to Stage C and 6 (21.4%) to Stage D. The results suggested that this system of mass screening program for PC combined with the annual health checkup was suitable for the future "national-level" screening.

SIGNIFICANCE AND FUTURE OF PROSTATE-SPECIFIC ANTIGEN (PSA, Tandem) IN THE MASS SCREENING FOR PROSTATE CANCER

The significance of prostate-specific antigen (PSA) measured with a Tandem PSA kit in 2230 serum samples examined by mass screening for prostate cancer was investigated.In 1985-1991, subjects were examined by digital rectal examination (DRE) and prostatic acid phosphatase (PAP), and in 1992, subjects were examined by DRE, transrectal sonography (TRUS) and PSA using an E-test TOSOH II Kit.1) The cut off value was determined between non-cancer subjects and prostate cancer patients. When the cut off value was 5.5ng/ml, the sensitivity, specificity and accuracy as a prostate marker were 73.9%, 95.3%, and 94.6%, respectively.2) The relationship between serum PSA coscentration, prostate size estimated by TRUS and age was investigated. The serum PSA was directly correlated with patient age and prostatic volume. The serum PSA concentration increased by 0.04ng/ml/year.3) The PPV (positive predictive value) of PSA (26.1%) is better than that for DRE (7.4%) or TRUS (8.1%). Thr sensitivity of PSA, DRE and TRUS is 73.9%, 49.6% and 21. 4%, respectively

血清γ-seminoprotein と prostate-specific antigen 測定値の相関性についての臨床的検討

Serum levels of prostatic acid phosphatase (PAP), gamma-seminoprotein (gamma-Sm) and prostate-specific antigen (PSA) were determined simultaneously in 57 patients with benign prostatic hyperplasia (BPH) and in 50 untreated patients with prostatic cancer (adenocarcinoma, N = 47 and non-adenocarcinoma, N = 3). The correlations between the serum levels of gamma-Sm and PSA in these patients were assessed by linear regression analysis. Some fundamental studies were added for explaining the causes of discrepancy between the serum levels of gamma-Sm and PSA. All of BPH group underwent transurethral resection of the prostate (TURP) and the sera were obtained for measurements before, immediately after and 18 hours after TURP. The gamma-Sm correlated well with the PSA in the sera obtained before (r = 0.76) and 18 hours after (r = 0.73) TURP. However, there was no correlation (r = 0.26) between them in the sera obtained immediately after TURP. In 47 untreated patients with adenocarcinoma of the prostate, no significant correlation (r = 0.19) between serum levels of gamma-Sm and PSA was observed, although there was correlation (r = 0.51) between those of PAP and PSA. When these patients were classified into two groups, M0 (stage A-C; N = 26) and M1 (stage D; N = 21), however, the serum gamma-Sm correlated with the serum PSA in M0 group (r = 0.57), but didn't in M1 group (r = 0.11). Furthermore, the differences in the means of PAP (p less than 0.05) and PSA (p less than 0.001) between M0 group and M1 group were statistically significant, although the serum gamma-Sm failed to distinguish M0 from M1. The anti-PSA antibody of "PSA Kit" reacted against the standard gamma-Sm adopted from "gamma-Sm Kit". Surprisingly, the anti-gamma-Sm antibody of "gamma-Sm Kit" also reacted against the standard PSA adopted from "PSA Kit". The gamma-Sm and PSA apparently cross-reacted each other. The quantitative analyses with serial dilution of the sera were done by using each assay in 3 patients whose serum levels of gamma-Sm were markedly different from those of PSA. The dilution curve for PAP appeared to be rectilineal, and that for PSA also appeared to be approximately rectilineal. However, the gamma-Sm assay failed to be proportional. In conclusion, the correlation between serum levels of gamma-Sm and PSA was absent in certain circumstances, when the true values of them were expected to be much higher than those determined.(ABSTRACT TRUNCATED AT 400 WORDS)

Identity of Prostate Specific Antigen and the Semen Protein P30 Purified by a Rapid Chromatography Technique

Previous investigators have reported the identity of prostate specific antigen (PSA) and the semen protein p30, but data to support these claims have not been published. We report here the rapid and continuous purification of PSA using a simple two column chromatography technique originally developed for purification of p30. Using commercial antisera to PSA and original antisera to p30 for detection, we show that the two glycoproteins have identical purification profiles by this technique which uses cation exchange chromatography and sizing chromatography. The antigens also have identical molecular weights by gel electrophoresis and gel filtration. Furthermore, both antigens correspond to the same prominent protein band in seminal plasma by sodium dodecylsulfate polyacrylamide gel electrophoresis. On commercial immunoassay for PSA, purified p30 gives a calibration curve identical to the commercial PSA kit calibrator (Pros-check™ PSA Radioimmunoassay, Yang Laboratories). We conclude that PSA and the semen protein p30 are identical and can be easily purified by a rapid continuous technique.

Evaluation of commercial immunoperoxidase kits in diagnosis of prostate carcinoma

Comparison of one commercial immunoperoxidase kit for prostate specific acid phosphatase (PSAP) and two for prostate specific antigen (PA) with an unlabelled antibody peroxidase-antiperoxidase (PAP) technique using rabbit antihuman PSAP revealed generally good reproducibility of results on formalin fixed, paraffin-embedded sections of primary and metastatic prostatic carcinoma. Frequency of positivity was 92 per cent with both our noncommercial PAP and the kit method for PSAP, and 82 per cent and 89 per cent with kits for PA. Thus, sensitivity, with the PA kits was less than with our noncommercial PAP and the kit PSAP, with less intense immunostain and occasional false negatives. Specificity was good with all three kits, and no false positive results were obtained. Commercial immunoperoxidase kits provide a relatively easy and inexpensive means for practicing pathologists in a service-oriented setting to make more precise diagnoses in cases of poorly differentiated or metastatic carcinoma of prostatic origin.