Prostate-specific Antigen Sampling Research Articles

Label-free long-range detection of prostate cancer biomarkers based on surface-enhanced Raman scattering

In the field of prostate cancer based on surface-enhanced Raman scattering (SERS), the repeatability of detection is crucial for its practical application in clinical medicine. We propose to use a new SERS substrate based on a polymer planar waveguide in combination with microfluidic technology and utilized in the label-free detection of prostate-specific antigen (PSA) in serum. The experimental results show that the detection limit of the substrate for PSA sample solution is as low as 10 pg ml−1. Additionally, the optimal transmission length for PSA is determined to be 9 mm. Further examinations encompass repetitive testing of serum samples spiked with PSA at a concentration of 4 ng ml−1, revealing a relative standard deviation (RSD) of 5.01%. This outcome is compared with single-point detection, manifesting a notable enhancement of 9.81% in terms of RSD, signifying a marked improvement in repeatability. Notably, our method not only capitalizes on the long-range averaging effect to enhance the repeatability of Raman signals, but also circumvents sample damage resulting from direct laser irradiation.

Transperineal laser ablation (TPLA) with ultrasound/MRI fusion guidance in the treatment of localized radiotherapy-resistant prostate cancer

Objective The objective of this study was to assess the technical feasibility, safety, and efficacy of transperineal laser ablation (TPLA) guided by ultrasound/magnetic resonance (MR) fusion as a salvage treatment for refractory focal prostate cancer. Methods A total of five patients who had undergone radiation therapy (RT) for prostate carcinoma and biochemical recurrence, confirmed by both prostate-specific antigen (PSA) levels and MRI (3T mpMRI), were enrolled in this study. Focal ablation was performed using a 1064 nm diode laser. Post-ablation follow-up was conducted for a duration of 18 months, which included regular PSA sampling, 3T mpMRI, and ultrasound/MR fusion-guided biopsies systematic and targeted at the site of the focal treatment. Results The focal ablation procedure was carried out in an outpatient setting regimen with optimal clinical and biochemical outcomes. No recurrence was detected throughout the follow-up period. Conclusion TPLA focal treatment effectively manages local recurrences of RT refractory prostate cancer without side-effects or complications. Preservation of quality of life and functional outcomes, along with a >70% reduction in PSA, were achieved. Advances in knowledge Our study investigated TPLA as a salvage treatment for low-risk recurrent prostate cancer after RT, demonstrating its tolerability, feasibility, and effectiveness.

Systematic Optimisation of Microtiter Plate Lectin Assay to Improve Sialic Acid Linkage Detection.

We aimed to develop a high-throughput lectin assay with minimized background signals to investigate the interactions of lectins and sialic acid glycans, focusing on Prostate- Specific Antigen (PSA). High background signals resulting from nonspecific binding are a significant concern for microtiter plate-based Enzyme-Linked Lectin Sorbent Assays (ELISAs), as they can mask specific binding signals and cause false-positive results. In this study, we constructed an ELISA based on different washing step parameters, including the number of washing cycles, NaCl and Tween-20 concentrations, and the type of blocking agent and evaluated the effects on both specific and nonspecific binding signals. Furthermore, we performed a PSA binding assay using the optimized ELISA. The optimal washing parameters based on the highest specific binding signal proposed four cycles of washing steps using a washing buffer containing a high salt concentration (0.5 M NaCl) and mild detergent (0.05% Tween-20). The utilization of the optimized washing parameters in this assay was shown to be sufficient to obtain the optimal binding signals without the use of any blocking agent. Binding assays performed using the optimized ELISA revealed that the glycan of the PSA sample used in this study mainly consists of terminal α2,6-linked sialic acid, as strongly recognized by Sambucus nigra agglutinin (SNA) with a KD value of 12.38 nM. The ELISA reported in this study provides a simple yet sensitive assay for sialic acid linkage recognition.

Rational design of effective solid-state electrochemiluminescence platform of Gold@Polyluminol nanocomposite as an ultrasensitive immuno-probe for selective detection of prostate specific antigen

An electrodeposited gold@poly-luminol nanocomposite on glassy carbon electrode (Au@PL-NC/GCE) has been developed and demonstrated as solid-state electrochemiluminescence (ECL) immunosensor platform for prostate specific antigen (PSA) sensing. In-situ electro-generated reactive oxygen species (ROS) from oxygen reduction reaction in oxygen saturated PBS (pH 7.4) acts as sole co-reactant augmenting the signal transduction. Protein-G bio-affinity layer interfaced with Au@PL-NC/GCE (Protein-G/Au@PL-NC/GCE) to support the effective localization of Fc region of the monoclonal antibodies of PSA (mAb-PSA). As-developed ECL probe exhibit selective recognition of target analyte, PSA, enabling wide linearity of 1 fg mL−1 to 10 μg mL−1 with a calculated limit of detection (LOD) and limit of quantification (LOQ) of 0.45 fg mL−1 and 1.37 fg mL−1, respectively. The selectivity and specificity of the ECL probe was tested using human serum albumin, immunoglobulin G and mixtures of the same with target analyte. Fabricated ECL probe not only exhibit high sensitivity and specificity against commercial PSA samples but also enable clinical detection in real human serum and urine samples with acceptable recovery range from 97% to 103%. Our results suggest that the fabricated reagent-less solid-state ECL platform holds promising application in the field of prostate oncological screening and its point-of-care applications.

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.

Analytical performance of thrombospondin-1 and cathepsin D immunoassays part of a novel CE-IVD marked test as an aid in the diagnosis of prostate cancer.

The Prostate Specific Antigen (PSA) test suffers from low specificity for the diagnosis of Prostate Cancer (PCa). We originally discovered two cancer-related proteins thrombospondin-1 (THBS1) and cathepsin D (CTSD) using a mass-spectrometry-based proteomics approach. The two serum proteins were shown to improve the diagnosis of high-grade PCa. Thus, we developed quantitative ELISAs for the determination of their concentration in human serum. Here we report their analytical performance in terms of limit of detection, specificity, precision, linearity and interferences, which were determined based on CLSI guidelines. Further, we investigated the influence of pre-analytical factors on concentration measurements. For this, blood from 4–6 donors was collected in different tubes and stored at room temperature for different times prior to centrifugation at different centrifugal forces and temperatures. Stability of THBS1 and CTSD under different storage temperatures was also evaluated. Our results show that the assays are specific, linear and sensitive enough to allow measurement of clinical samples. Precision in terms of repeatability and total within-laboratory coefficient of variation (CV) are 5.5% and 8.1% for THBS1 and 4.3% and 7.2% for CTSD, respectively. Relative laboratory-to-laboratory differences were -6.3% for THBS1 and -3% for CTSD. Both THBS1 and CTSD were stable in serum samples, with 80–120% recoveries of concentrations across donors, sample preparation and storage. In conclusion, the ELISAs as part of the novel commercial in vitro diagnostic test Proclarix are suitable for the use in clinical practice. THBS1 and CTSD can be accurately measured for their intended use independent of the lot and laboratory when conditions consistent with routine practice for PSA sampling and storage are used.

Detection of prostate cancer by Raman spectroscopy: A multivariate study on patients with normal and altered PSA values

Digital rectal examination (DRE) was the primary means to detect prostate diseases. The DRE has a high variability as it is based manly in the tactile sensitivity and expertise of the examiner. The prostate-specific antigen (PSA) test was initially developed for surveillance of prostate cancer and later it was also used as a diagnosis test. Raman spectroscopy is a powerful analytical technique that can measure the chemical composition of complex biological samples, such as body fluids. Biochemical changes caused by diseases can lead to significant changes in the Raman spectra. This study aimed to identify the differences in the Raman spectra of serum samples with normal and altered PSA values and correlate these differences by using multivariate techniques (principal component analysis - PCA and partial least squares regression - PLS). A total of 321 spectra were collected from 108 subjects. Two hundred and seventy were obtained from 91 non-altered PSA samples and 51 spectra from 17 samples with altered PSA. Each spectrum acquired was standardized to the area under the curve (1-norm). Discriminating and quantitative models employing PCA and PLS were developed. The PCA analyses showed 85.7% predictive power (87.41% sensitivity and 76.47% specificity). The PLS test showed a near-perfect sensitivity (98.51%) and an intermediate specificity (62.75%). The quantitative model through PLS regression showed a good correlation between PSA values and the spectral features (r=0.605). This preliminary study suggests that Raman spectroscopy could be efficiently used for screening patients with altered PSA as well as for follow-up of the treatment of the prostate cancer by using initially the PLS to identify the possible presence of the prostate cancer and later on use de PCA to confirm the diagnosis.

Assessment of Risk for Interference by Circulating Biotin in Samples Received for High Sensitivity Troponin-T, Thyrotropin, and for Prostate Specific Antigen Testing by Immunoassays.

Biotin interference in streptavidin-based immunoassays is known and may lead to erroneous results and thus to diagnostic error. The recent increase in reports of biotin interference in immunoassay-based testing has been attributed to increased intake of biotin supplements by the public and to the high dose biotin therapy in patients with neurological and inherited disorders. Circulating biotin levels greater than 20 ng/mL are reported to exhibit interference in high sensitivity troponin T (hs-TnT), thyroid stimulating hormone (TSH), and in prostate specific antigen (PSA) among other assays when using our Cobas® 6000 immunoassay analyzer (Roche Diagnostics, IN, USA). This study aims to examine the risk for biotin interference among our patient population. Serum and plasma leftover samples from 183 different patients were collected following completion of hs-TnT (53 samples), TSH (45 samples), and PSA (85 samples) testing. Aliquots were stored frozen at -20°C until analysis. Biotin concentrations in these samples were measured using an ELISA (ALPCO, Salem, NH, USA) according to the manufacture's protocol. Samples with biotin levels of 20 ng/mL or greater were considered as high-risk samples (HRS) for biotin interference. The overall concentrations of biotin in our patients' samples ranged from 0.02 ng/mL to 11.38 ng/mL (median 0.42 ng/mL). The median and (range) biotin concentrations in hs-TnT, TSH, and PSA samples were 0.27 ng/mL (0.02 - 6.86 ng/mL), 0.39 ng/mL (0.08 - 11.38 ng/mL), and 0.47 ng/mL (0.09 - 7.73 ng/mL), respectively. Although there was no significant difference between biotin levels in samples for TSH or PSA measurement (p = 0.85), biotin in samples for PSA and for hs-TnT and in samples for TSH and hs-TnT were significantly different (p = 0.049 and 0.089), respectively. None of the samples had biotin levels greater than or equal to 20 ng/mL. Using representative samples with requests for hs-TnT, TSH, and PSA testing, where reliable performance for the selected assays at their lowest measurement range is required for clinical intervention, among our study population the risk was considered minimal as their circulating biotin levels were less than 20 ng/mL. However, educating clinicians and laboratory users regarding the potential of biotin interference is always recommended.

A fluorometric aptamer based assay for prostate specific antigen based on enzyme-assisted target recycling

Prostate specific antigen (PSA) is considered to be a well-established biomarker for prostate cancer, and the importance of PSA assay is increasing in order to improve the diagnosis and prognosis of prostate cancer. However, there are still some weaknesses with current methods of PSA detection including high-cost, heavy analyzer and complexed procedure, restricting the application of PSA assay in prevention of diseases. In this paper, we designed a novel fluorometric aptasensor for PSA assay. Inspired by the concept of enzyme-assisted target recycling (EATR), this novel aptasensor shows an excellent signal responsiveness by the exclusive recognition between aptamer and PSA, together with significant signal amplification through EATR. After systematic optimization, this method shows an excellent detective performance with a sensitive LOD at 0.043 pg mL−1(S/N = 3) and wide linear range of 0.05–150 pg mL−1. To verify the potential of practical application, a set of biomarkers that often co-exist in PSA samples and diluted human serum samples are used for selectivity and practical performances evaluation, and it turns out that this aptasensor exhibits selectivity and potential for clinical application. Specially, this method is easily performed under isothermal environment and needless of complexed preparation, making it more possible for wide application. In view of the superiority, a promising perspective can be provided by this method for practical PSA assay, further promoting the development of precise medicine and oncology.

An In-Depth Glycosylation Assay for Urinary Prostate-Specific Antigen.

The concentration of prostate-specific antigen (PSA) in serum is used as an early detection method of prostate cancer (PCa); however, it shows low sensitivity, specificity, and a poor predictive value. Initial studies suggested the glycosylation of PSA to be a promising marker for a more specific yet noninvasive PCa diagnosis. Recent studies on the molecular features of PSA glycosylation (such as antenna modification and core fucosylation) were not successful in demonstrating its potential for an improved PCa diagnosis, probably due to the lack of analytical sensitivity and specificity of the applied assays. In this study, we established for the first time a high-performance PSA Glycomics Assay (PGA), allowing differentiation of α2,6- and α2,3-sialylated isomers, the latter one being suggested to be a hallmark of aggressive types of cancer. After affinity purification from urine and tryptic digestion, PSA samples were analyzed by CE-ESI-MS (capillary electrophoresis–electrospray ionization coupled to mass spectrometry). Based on positive controls, an average interday relative standard deviation of 14% for 41 N-glycopeptides was found. The assay was further verified by analyzing PSA captured from patients’ urine samples. A total of 67 N-glycopeptides were identified from the PSA pooled from the patients. In summary, the first PGA successfully established in this study allows an in-depth relative quantitation of PSA glycoforms from urine. The PGA is a promising tool for the determination of potential glycomic biomarkers for the differentiation between aggressive PCa, indolent PCa, and benign prostate hyperplasia in larger cohort studies.

Analysis of urinary PSA glycosylation is not indicative of high-risk prostate cancer

The levels of core fucosylation and α2,3-linked sialic acid in serum Prostate Specific Antigen (PSA), using the lectins Pholiota squarrosa lectin (PhoSL) and Sambucus nigra agglutinin (SNA), can discriminate between Benign Prostatic Hyperplasia (BPH) and indolent prostate cancer (PCa) from aggressive PCa. In the present work we evaluated whether these glycosylation determinants could also be altered in urinary PSA obtained after digital rectal examination (DRE) and could also be useful for diagnosis determinations. For this purpose, α2,6-sialic acid and α1,6-fucose levels of urinary PSA from 53 patients, 18 biopsy-negative and 35 PCa patients of different aggressiveness degree, were analyzed by sandwich ELLA (Enzyme Linked Lectin Assay) using PhoSL and SNA. Changes in the levels of specific glycosylation determinants, that in serum PSA samples were indicative of PCa aggressiveness, were not found in PSA from DRE urine samples. Although urine is a simpler matrix for analyzing PSA glycosylation compared to serum, an immunopurification step was necessary to specifically detect the glycans on the PSA molecule. Those specific glycosylation determinants on urinary PSA were however not useful to improve PCa diagnosis. This could be probably due to the low proportion of PSA from the tumor in urine samples, which precludes the identification of aberrantly glycosylated PSA.

Sensitive and selective detection of prostate-specific antigen using a photonic crystal nanolaser.

The detection of low-concentration biomarkers is expected to facilitate the early diagnosis of severe diseases, including malignant tumors. Using photonic crystal nanolaser sensors, we detected prostate-specific antigen (PSA) from a concentration of 1 fM, which is difficult to detect by conventional enzyme-linked immunosorbent assay. The signal intensity and stability were improved by using a surfactant (i.e., ethanolamine). Even when a contaminant such as bovine serum albumin was mixed into the PSA sample, thereby increasing the concentration of the contaminant ten billion times, it was still possible to maintain a high level of detection.

Effect of ejaculation on Serum Prostate-Specific Antigen concentration

ABSTRACT Purpose:To evaluate the effect of ejaculation on serum prostate-specific antigen (PSA) concentrations in patients with lower urinary tract symptom (LUTS).Materials and Methods Our study includes 98 men (62 study and 36 control). After three days of sexual abstinence, blood samples were drawn for the measurement of baseline PSA levels. Then the patients were told to ejaculate. One, 5, 24 and 72 hours after ejaculation, serum total (tPSA), free (fPSA) and complexed PSA (cPSA) levels were measured. Serum PSA sampling was performed at the same intervals in the control group without ejaculation.Results The mean age in study and control groups patients were 59.03±0.99 years, 61.14±1.30 years, respectively. In the study group, changes in tPSA and fPSA levels after ejaculation were found statistically significant while changes in cPSA levels and f/tPSA ratios were not significant (p=0.016, p=0.0003, p=0.176, and p=0.173, respectively). Baseline values showed significant differences with 1st and 5th hours. No significant changes in tPSA, fPSA, cPSA levels and f/tPSA values were found in control group (p=0.223, p=0.224, p=0.444, and p=0.718, respectively). The changes in the number of patients exceeding the cutoff values after ejaculation were not statistically significant for tPSA, cPSA, and f/tPSA ratio.Conclusions In this study, ejaculation increased tPSA and fPSA concentrations but it didn’t have a significant effect on serum cPSA levels and f/tPSA ratios. However, recent ejaculation may affect the biopsy indication at least near cut off PSA values. Further studies are needed to explain the mechanisms of alterations in the concentration of PSA.

Vaginal Prostate Specific Antigen (PSA) Is a Useful Biomarker of Semen Exposure Among HIV-Infected Ugandan Women.

The practical feasibility of using prostate specific antigen (PSA) as a biomarker of semen exposure was examined among HIV-infected Ugandan women. Vaginal fluids were obtained with self-collected swabs and a qualitative rapid test (ABAcard®p30) was used to detect PSA. Trained laboratory technicians processed samples on-site and positive PSA tests were compared to self-reported unprotected vaginal sex (UVS) in the last 48h. A total of 77 women submitted 126 samples for PSA testing at up to three study visits. Of these samples, 31% (n=39/126) were PSA positive, and 64% (n=25/39) of the positive PSA samples were accompanied by self-report of no UVS at the study visit the PSA was collected. There were no reported difficulties with specimen collection, storage, or processing. These findings provide preliminary data on high levels of misreported UVS among HIV-infected Ugandan women using practically feasible methods for PSA collection and processing.

MP21-03 HOW ACCURATE IS THE PSA TEST? A PREVALENCE STUDY OF DISTURBED PSA VALUES IN A TERTIARY REFERRAL HOSPITAL

You have accessJournal of UrologyProstate Cancer: Detection & Screening III1 Apr 2016MP21-03 HOW ACCURATE IS THE PSA TEST? A PREVALENCE STUDY OF DISTURBED PSA VALUES IN A TERTIARY REFERRAL HOSPITAL Cedric Poyet, Karim Saba, Noemie Lautenbach, Lanja Saleh, Martin Umbehr, Tullio Sulser, Michael Müntener, and Arnold von Eckardstein Cedric PoyetCedric Poyet More articles by this author , Karim SabaKarim Saba More articles by this author , Noemie LautenbachNoemie Lautenbach More articles by this author , Lanja SalehLanja Saleh More articles by this author , Martin UmbehrMartin Umbehr More articles by this author , Tullio SulserTullio Sulser More articles by this author , Michael MüntenerMichael Müntener More articles by this author , and Arnold von EckardsteinArnold von Eckardstein More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.637AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Prostate specific antigen (PSA) is of paramount importance for the detection and monitoring of patients with prostate cancer. We and others have reported artifical altered PSA levels due to the presence of heterophilic antibodies (hA). Unrecognized artifical high PSA levels due to hA can lead to severe overtreatment of patients. The prevalence of altered PSA levels due to hA interference or other factors is unknown. METHODS Recoveries of all PSA samples taken consecutively in our hospital from February to May 2014 using a 3rd generation electrochemoluminescence assay (ECLIA) from Roche diagnostics were determined by diluting the patient samples with a standard serum of known PSA concentration. Samples with recoveries <80% or >130% of the expected values were retested and PSA was determined again after adding a blocking reagent for hAs (Scantibodies Laboratory, Santee, CA). RESULTS A total of 1500 serum probes were consecutively analyzed. Four out of 1500 probes (0.27%) showed reproducibly disturbed recoveries. Two samples showed falsely-elevated PSA values (Sample 1: 62.5-fold falsely-elevated; Sample 2: 1.6-fold falsely-elevated). The other two samples showed falsely-low PSA values (Sample 3: 8263-fold falsely-decreased; Sample 4: 31-fold falsely-decreased) (Table 1). After pretreatment of the patient sera with a blocking reagent for hAs, 3 out of 4 samples showed normal recoveries. Sample 3 could not be reanalyzed because of lack of original sample material and patients death. CONCLUSIONS We conclude that about 0.3% of PSA tests by the 3rd generation Roche are disturbed. Although a very rare event this interference puts a relevant amount of patients worldwide at risk of over- or underdiagnostics. Manufacturers and clinical laboratories should know the rates and kinds of interference for their PSA test used. In case of clinically implausible high or low PSA levels, clinicians should rule out sampling errors and repeat PSA tests by including determinations of recoveries, and, if pathological, absorbing hA in the serum of the patients. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e245 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Cedric Poyet More articles by this author Karim Saba More articles by this author Noemie Lautenbach More articles by this author Lanja Saleh More articles by this author Martin Umbehr More articles by this author Tullio Sulser More articles by this author Michael Müntener More articles by this author Arnold von Eckardstein More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Characterization of the Glycosylation Site of Human PSA Prompted by Missense Mutation using LC-MS/MS.

Prostate specific antigen (PSA) is currently used as a diagnostic biomarker for prostate cancer. It is a glycoprotein possessing a single glycosylation site at N69. During our previous study of PSA N69 glycosylation, additional glycopeptides were observed in the PSA sample that were not previously reported and did not match glycopeptides of impure glycoproteins existing in the sample. This extra glycosylation site of PSA is associated with a mutation in KLK3 genes. Among single nucleotide polymorphisms (SNPs) of KLKs families, the rs61752561 in KLK3 genes is an unusual missense mutation resulting in the conversion of D102 to N in PSA amino acid sequence. Accordingly, a new N-linked glycosylation site is created with an N102MS motif. Here we report the first qualitative and quantitative glycoproteomic study of PSA N102 glycosylation site by LC-MS/MS. We successfully applied tandem MS to verify the amino acid sequence possessing N102 glycosylation site and associated glycoforms of PSA samples acquired from different suppliers. Among the three PSA samples, HexNAc2Hex5 was the predominant glycoform at N102, while HexNAc4Hex5Fuc1NeuAc1 or HexNAc4Hex5Fuc1NeuAc2 was the primary glycoforms at N69. D102 is the first amino acid of "kallikrein loop", which is close to a zinc-binding site and catalytic triad. The different glycosylation of N102 relative to N69 might be influenced by the close vicinity of N102 to these functional sites and steric hindrance.

Sniffing out prostate cancer: a new clinical opportunity.

Sniffing out prostate cancer: a new clinical opportunity.

Effects of ejaculation on serum prostate-specific antigen levels

The aim of this study is to evaluate the effect of ejaculation on serum total, free and complex prostate-specific antigen (PSA) levels and their effect on biopsy decisions. Our study includes 47 men older than 45 years with symptomatic benign prostatic hyperplasia (BPH). Patients' PSA levels were under 2.5 ng/mL, and there were no known conditions to preclude ejaculation. Eight patients with similar demographic, and clinical characteristics were chosen as a control group. With three days of sexual abstinence, blood samples were drawn for the measurement of baseline PSA levels, and then the patients were told to ejaculate. One, 5, 24 and 72 hours after ejaculation, serum total, free and complexed PSA levels were measured. Serum PSA sampling was performed at the same intervals in the control group without ejaculation. The mean age of the patients was 59.13±1.38 years in the study group, and 63.75±3.13 years in the control group. The mean international prostate symptom scores (IPSS) were 11.78±1.12 and 11.63±3.32 in the study, and the control groups, respectively. The mean baseline total, free, and complexed PSA values were 1.07±0.09, 0.31±0.03, and 0.71±0.08 ng/mL, respectively. In the study group, total PSA value was found to be 1.29±0.12 ng/mL (p=0.008) at first hour after ejaculation, and this change was statistically significant when compared with baseline values. Mean total PSA level rose up to 1.28±0.13 ng/mL (p=0.05) by the 5(th) hour after ejaculation, but this change was not statistically significant relative to the baseline values. Mean free PSA level rose after the first hour postejaculation to 0.37±0.04 ng/mL (p=0.01) and after the fifth hour postejaculation to 0.37±0.04 ng/mL (p=0.002), and these changes were statistically significant relative to the baseline values. There were no statistically significant changes at the other sampled times as for the total, free or complexed PSA serum levels. When all three values were considered individually, in only 2.12% of the patients, biopsy decisions could be affected by the elevation in PSA levels. When the PSA value is borderline with respect to biopsy decisions, the effect of ejaculation on serum PSA levels may be clinically important. In these patients, ejaculation must be questioned, and repeated. PSA levels should be evaluated 24 hours after ejaculation. There were no statistically significant changes in the levels of complex PSA values. Further studies are needed to clarify the relationship between complexed PSA and ejaculation.

Hiperplasia Prostática Benigna e PSA: o efeito dominó

Após a publicação de uma recomendação contra o rastreio câncer prostático pela U.S. Preventive Services Task Force, a comunidade médica não poderá desvincular-se das particularidades relacionadas com o antígeno prostático específico (PSA). O enfoque dado às guidelines da Hiperplasia Prostática surge pela possível partilha, a determinado ponto da sua abordagem, de um trilho que cursa também com a solicitação do PSA. Os resultados de dois grandes ensaios clínicos constituem o maior corpo da evidência actual e deles sobressai que o número de homens que evitaram a morte por câncer prostático após submetidos ao rastreio foi reduzido. Há evidência de que 100-200 em 1000 homens rastreados terão um falso-positivo, a maioria dos quais será biopsada, com possíveis danos psicológicos e orgânicos. O Médico de Família deverá relembrar que não é recomendado que se ofereça esta análise, sem que primeiro discuta, juntamente com o paciente, as questões inerentes ao PSA.

1,2-Fucosylated and -N-acetylgalactosaminylated prostate-specific antigen as an efficient marker of prostatic cancer

A prostate-specific antigen (PSA) is widely used as a diagnostic marker for prostate cancer (PC) because of its high specificity. However, elevated serum PSA does not occur only in PC but also in benign prostatic hyperplasia (BPH). Since the structural changes of N-glycans during carcinogenesis are common phenomena, we investigated whether PC-specific N-glycans are linked to PSA. We first analyzed the carbohydrate structures of PSA derived from seminal fluid, serum of BPH and PC patients, and PC cell line, namely, LNCaP using eight lectin-immobilized columns and then with enzyme-linked immunosorbent assay (ELISA). The fraction of serum PSA from PC patients bound to both Fucalpha1-2Gal and betaGalNAc binding Trichosanthes japonica agglutinin-II (TJA-II) column, while that from BPH patients did not exhibit this binding ability, thereby implying that there is elevated expression of alpha1,2-fucosylation and beta-N-acetylgalactosaminylation of PSA during carcinogenesis. We then performed a real-time polymerase chain reaction (PCR) and confirmed that these structural changes were responsible for the elevated expression of fucosyltransferase I (FUT1) and beta-N-acetylgalactosaminyltransferase 4(B4GALNT4). Second, we measured TJA-II-bound PSA contents and the binding ratios of TJA-II column chromatography in serum PSA samples from 40 patients of both PC and BPH. The results indicated that both TJA-II-bound PSA content and TJA-II binding ratios (%) could be used to discriminate between PC and BPH with more than 95% probability, and TJA-II-bound PSA can be regarded as a potential marker of PC.