Increase In Prostate-specific Antigen Concentration Research Articles

Association between serum urea nitrogen levels and prostate-specific antigens (NHANES 2003–2010)

BackgroundIncreasing evidence suggests that serum urea nitrogen may be a risk factor for prostate cancer (PCa) and influence serum prostate-specific antigen (PSA) concentrations, but direct evidence of a relationship between PSA and serum urea nitrogen levels in the general population is still lacking. The aim of this study was to demonstrate the relationship between serum urea nitrogen levels and prostate-specific antigen (PSA) and prostate cancer.MethodsWe conducted a cross-sectional study using the National Health and Nutrition Examination Survey (NHANES, 2003–2010) database. We performed a multifactorial regression analysis of the association between serum urea nitrogen levels and PSA and PCa, followed by subgroup analyses.ResultsA total of 5256 subjects were included in this study, and after adjusting for demographic, biological, and immunologic variables, we found that there was a threshold for blood urea nitrogen concentration below which every 1 ng/mL increase in serum urea nitrogen was associated with a 0.0325 ng/mL increase in PSA concentration (log2 transformed) (95% CI: 0.0064, 0.0586), and the P trend was was less than 0.05 and the difference was statistically significant. Sensitivity analyses using the generalized additive model (GAM) showed a linear relationship between serum urea nitrogen and serum PSA concentrations when blood urea nitrogen concentrations ranged from 0 ng/ml to 6.78 ng/ml.ConclusionSerum urea nitrogen was independently and positively correlated with serum PSA concentration when the concentration of serum urea nitrogen ranged from 0 ng/ml to 6.78 ng/ml.

Potential-resolved ratiometric electrochemiluminescence detection for prostate-specific antigen based on CdS nanocrystals modified on carbon nanotubes and luminol functionalized nanocomposites.

A ratiometric electrochemiluminescence (ECL) aptamer-based sensing platform was fabricated for prostate-specific antigen (PSA) determination. Activated CdS nanocrystals/multi-walled carbon nanotubes (CdS/MCNTs) and luminol-Pt/PAMAM nanocomposites (L-Pt/PAMAM NCs) were synthesized and used as cathodic and anodic ECL emitters, respectively. Amino group-modified aptamers were assembled on carboxylated magnetic beads, followed by hybridization with probe DNA functionalized L-Pt/PAMAM NCs. In the presence of PSA, the aptamer would bind specifically to the target PSA, thereby releasing L-Pt/PAMAM NCs. After magnetic separation, the separated L-Pt/PAMAM NCs would hybridize with capture DNA on CdS/MCNTs coated on glassy carbon electrode. This binding would lead to a decrease in cathodic ECL signal of CdS/MCNTs, due to the efficient energy transfer from CdS/MCNTs to L-Pt/PAMAM NCs. Meanwhile, L-Pt/PAMAM brought the anodic ECL signal from luminol. With the increase of PSA concentration, the ECL emission from luminol increased and the ECL emission from CdS/MCNTs decreased. The ratio of ECL intensity of luminol at 0.55V and CdS/MCNTs at - 1.25V could be used to quantify the concentration of PSA. This method enables sensitive and reliable detection of PSA over a wide range from 0.05 to 200ngmL-1, and the detection limit is 0.02ngmL-1.

Effects of cycling and rowing on serum concentrations of prostate-specific antigen: A randomized study of 101 male subjects.

To determine the effects if cycling and rowing on serum prostate-specific antigen (PSA) levels. Male volunteers (n = 101), aged 20-80 (mean, 49.9) years were randomized to exercise at the first or second study visit. They performed 1 h of either cycling or rowing on a stationary machine. To determine exercise-induced effects on the PSA level, serum total PSA (tPSA) and free PSA (fPSA) concentrations were evaluated before and after exercise and another sampling was performed at the second study visit. Pre-exercise and postexercise tPSA and fPSA concentrations were compared using the Wilcoxon matched-pairs test. The results were analyzed using the Mann-Whitney U-test. A significant (p < 0.001) average increase in tPSA after exercise (1.14 ± 1.11 ng/ml to 1.24 ± 1.26 ng/ml [mean, +8.8%]) was observed after both cycling and rowing, without significant differences between the sports (p = 0.54). The exercise-induced increase in PSA concentration affected participants aged ≥50 years (difference, 0.16 ± 0.37; p < 0.001), but not those aged <50 years (difference, 0.01 ± 0.06; p = 0.23). The effect size was clinically irrelevant in all except two outliers, in whom a distinct increase of PSA level by averages of 1.80 ng/ml (+55%) for tPSA and 1.25 ng/ml (+227%) for fPSA following cycling was observed. Rowing and cycling generally do not have a clinically relevant effect on PSA levels. However, outliers exist. Our findings do not support abstaining from exercise during the days approaching PSA sampling.

A chemiluminescent dual-aptasensor capable of simultaneously quantifying prostate specific antigen and vascular endothelial growth factor

An aptasensor with guanine chemiluminescence detection was developed for the early diagnosis of prostate cancer with the simultaneous quantifications of prostate specific antigen (PSA) and vascular endothelial growth factor (VEGF). A PSA DNA aptamer conjugated with Texas Red emits red light in guanine chemiluminescence reaction, whereas a VEGF DNA aptamer conjugated with 6-FAM emits green light. The PSA and VEGF aptamers immobilized on the surface of paramagnetic beads mixed with a sample were incubated for 30 min. After the incubation, PSA and VEGF bound with PSA and VEGF aptamers were simultaneously quantified for 20 s using guanine chemiluminescence detections operated with two photomultiplier tubes and two optical filters capable of selectively collecting green or red light. With the increase of PSA concentration, the strength of the red light emitted from Texas Red dropped exponentially, whereas with the increase of VEGF concentration, the green light emitted from 6-FAM was enhanced. The limits of detection were as low as 0.6 ng/ml for PSA and 0.4 ng/ml for VEGF. We confirmed that the dual-aptasensor can be applied as an advanced and new medical device capable of simultaneously quantifying PSA and VEGF to early diagnose prostate cancer with good accuracy, precision, and reproducibility.

PSA spikes not always cause for alarm

A study from the Schiffl er Cancer Center, Wheeling, WV, USA investigated prostate-specifi c antigen (PSA) spikes in 164 patients who underwent brachytherapy with iodine-125 (I) or palladium-103 (Pd) as part of an ongoing prospective ran domised trial (Int J Radiat Oncol Biol Phys, published online June 1, 2007; DOI:10.1016/ j.ijrobp.2007.01.066). 61 patients also received short-course androgen depr iv ation treat ment. Bio chemical disease-free survival was defi ned as a PSA concentration ≤0·40 ng/ml after nadir, and a PSA spike was defi ned as an increase of ≥0·2 ng/ml, followed by a lasting decline to prespike concentrations. 44 patients (27%) developed a PSA spike. In patients receiving androgen deprivation treat ment, spike incid ence was comparable between the I (28·1%) and Pd (20·7%) groups; however, in the hormone-naive patients, spike incidence was 45·7% in the I group and 14% in the Pd group. Spike incidence was also greater in patients aged <65 years (38·5% vs 16·3%). Patients who undergo brachytherapy are thought to develop a transient increase in PSA concen tration, which can be wrongly interpreted as a sign of cancer recurrence. Study investigator Gregory Merrick says: “It is imperative that urologists and radiation oncologists are cognizant of this phenomenon to minimise unnecessary diagnostic and therapeutic intervention”. Nelson Stone (Mount Sinai School of Medicine, New York, USA) adds: “Patients with a PSA spike need to be observed before any additional treatment is considered. I recently had a patient [whose PSA concentration] spiked, and his primary urologist told him his treatment had failed and he would most likely die soon. Within a year, his PSA had fallen to an undetectable level. We do not know the reason why younger men are more likely to [have a PSA spike] after brachytherapy”. Merrick is hopeful that their results will lead to better management of patients with prostate cancer.

Prostate-specific antigen as predictor of prostate cancer in black men and white men.

The increasing incidence of prostate cancer creates complex issues in health care management and cost containment. There is a need to evaluate serial measurements of prostate-specific antigen (PSA) as a marker for long-term risk of clinically important prostate cancer (stages B through D). We used a nested case-control design within a retrospective cohort study to evaluate serial PSA concentrations in relation to subsequent prostate cancer diagnoses. Participants included 40 black and 96 white men with subsequent diagnoses of prostate cancer and 84 black and 100 white men without such diagnoses (control subjects) in a multiphasic health screening program conducted by the Kaiser Permanente Medical Care Program of Northern California. Serial serum samples were collected 1.5-23 years before prostate cancer diagnosis. Median serum PSA concentrations, specific for age and subsequent cancer status, were similar in blacks and whites. Concentrations in control subjects increased exponentially with age, with a doubling time of 24.9 years. Concentrations in men with stage A cancer were similar to those in control subjects. Until about 13 years before diagnosis, PSA in men with subsequent cancer stages B through D increased exponentially with age, with a doubling time similar to that of control subjects. Thereafter, the PSA concentrations increased exponentially, with a doubling time of 4.3 years. Rapid increase in PSA concentration started about 1.5 years earlier for men with stage D cancer than for men with stage B or C cancer. The single PSA measurement drawn closest to diagnosis was a more sensitive marker of stages B through D cancer within the next 7 years than was any index of change that also took account of earlier PSA readings. These data suggest that 1) age-specific PSA concentrations are similar in black men and white men and 2) current PSA concentration, specific for age, outperforms changes in past concentrations in identifying the man who will develop stage B, C, or D cancer within 7 years, albeit at the cost of a slightly higher rate of false-positive results. This interpretation needs confirmation in other data containing many serial PSA measurements within a few years of diagnosis.

Prostate Specific Antigen—a Screening Test for Prostatic Cancer?

A series of 287 patients referred by their family doctors with symptoms of bladder outflow obstruction were asked to attend the hospital for "pre-clinic" screening for carcinoma of prostate (CaP). Blood samples were collected from 211 patients and analysed for serum prostate specific antigen (PSA) and prostatic acid phosphatase (PAP). Thirty-six patients had a serum PSA greater than 10 micrograms/l and 7 had PAP levels greater than 5 iu/l. In no instance was the PAP elevated without an associated increase in PSA concentration. Patients with raised markers underwent further investigations which included prostatic biopsy and/or resection; 17 patients were proved to have carcinoma of the prostate, 9 of whom had distant metastases. The specificity of PSA for detecting prostate cancer in this study was 90% with a sensitivity of 89.5%, in contrast to values for PAP of 100% and 36.8%. The routine use of PAP as a marker for prostatic cancer should be abandoned. The use of PSA as a screening test in a group of patients with prostatism appears justified, but with a positive predictive value of only 47%, its use in a mass unselected screening programme is not recommended.