Biomedical subjects

R J Barren

Publications and source records attributed to R J Barren.

8 recordsLinked to original sources

PubMed1998

Method for identifying prostate cells in semen using flow cytometry.

BACKGROUND: Prostate-specific antigen (PSA) cannot differentiate benign prostatic hyperplasia (BPH), from prostatitis, or prostate cancer in the range of 4.0-10 ng/ml. An accurate cytologic or histologic assessment is necessary to confirm the proper diagnosis. The nature of a biopsy tends to make it a selective test not frequently repeated. We are reporting a technique employing semen as a source for the differential diagnosis of prostate epithelial cells. METHODS: Eleven vasectomized and nonvasectomized prostate cancer patients provided semen samples (stage T1 to T2). Two patients provided repeat samples. In addition, 15 vasectomized or nonvasectomized individuals without evidence of disease provided semen samples. Three million cells fixed with 50% ethanol were stained by an antibody (7E11.C5) to prostate-specific membrane antigen (PSMA), Hybritech Antibody (399) to PSA, and cytokeratin 8 and 18. In addition to the antibodies described, a DNA stain To-Pro 3 was used to identify 2n-4n DNA containing cells. A dual laser, Becton Dickinson FACSCaliber cytometer, was used to analyze the samples. RESULTS: All semen specimens contained diploid, cytokeratin 18-positive epithelial cells regardless of disease status. A clear difference between prostate cancer and normal prostate cell samples was observed using staining with 7E11.C5. The ratio of prostatic cells in the total epithelial cell population (PSMA:cytokeratin ratios) was calculated for each specimen. A retrospective study of sixteen semen samples from 11 prostate cancer patients had a mean PSMA:cytokeratin ratio of 0.57, whereas the samples from 15 patients without evidence of cancer had a mean PSMA:cytokeratin ratio of 0.11. This difference was significant. PSA staining was variable and inconsistent. CONCLUSIONS: This report demonstrates that human semen contains prostate cells that can be characterized and used in the clinical diagnosis of prostate cancer.

Adult↗

PubMed1997

Comparison of serum PSMA, PSA levels with results of Cytogen-356 ProstaScint scanning in prostatic cancer patients.

BACKGROUND: Stored serum from clinical trial cases undergoing ProstaScint (CYT-356) scanning were available for Prostate Specific Membrane Antigen (PSMA) assay. Prostate Specific Antigen (PSA) levels had already been determined. This provided an opportunity to see what correlations existed between the serum markers and the ProstaScint scan. A group of patients had the studies preprostatectomy, whereas another group had the studies postprostatectomy. METHODS: The scan results, serum PSA, serum PSMA, and clinical data were separately analyzed. PSMA serum levels were determined by Western blot. RESULTS: Preoperatively, radical prostatectomy patients showed a correlation between serum PSA or PSMA levels and the ProstaScint scan in the total group (n = 86), or in an untreated group (n = 38). Preoperatively, PSMA correlated with the pathological stage, whereas PSA correlated with the scan. Postoperatively, only PSMA serum levels correlated with the scan in an untreated group (n = 40). CONCLUSIONS: Preoperatively or postoperatively, Western blot PSMA serum levels predict the stage of disease or local, regional, or distant metastases, as shown by ProstaScint scan. Both the scan and the serum tests provide prognostic information and evaluate the extent of disease to a more significant degree than previously possible.

Adult↗

PubMed1997

Evaluation of PSA, free PSA, PSMA, and total and bone alkaline phosphatase levels compared to bone scans in the management of patients with metastatic prostate cancer.

BACKGROUND: Metastatic prostate cancer clinical evaluation is difficult. A revaluation of new prostate markers with regard to bone scans was performed. METHODS: Serial markers, including bone alkaline phosphatase (BAP), total alkaline phosphatase (TAP), prostate-specific antigen, total (PSA) and free (fPSA), and prostate-specific membrane antigen (PSMA), were obtained in patients under evaluation and treatment for possible or known metastatic prostate cancer. These were correlated with bone scan results (BSR). RESULTS: Seventy patients were observed from mid-October 1996-January 1997, during which time 171 serum samples were obtained and correlated with semiquantitative bone scan status. PSA and fPSA provided some correlation with BAP and BSR, but only at high levels (> 16-50 ng/ml). Receiver-operating curve (ROC) analysis demonstrated that BAP and TAP had a significant discriminating ability for positive and negative bone scans (> .78), compared to PSMA, PSA, and fPSA. However, percent BAP and TAP only correlated with BSR at a level above six lesions. As the lesions detected by BSR increased, the correlation increased. CONCLUSIONS: BAP is a valuable marker for clinical response evaluations to use in the serial follow-up of patients with metastatic prostate cancer, and correlates well with the bone scan as the number of lesions increase to > 6. PSA or fPSA show comparable results, but only at high levels (> 16-50 ng/ml).

Aged↗

PubMed1997

Monoclonal antibody 7E11.C5 staining of viable LNCaP cells.

BACKGROUND: Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein defined by the monoclonal antibody 7E11.C5. The 7E11.C5 antibody forms the basis of an in vivo diagnostic imaging agent (ProstaScint, Cyt-356) for identification of metastatic prostate cancer. The epitope on PSMA recognized by 7E11.C5 has been determined to be the first 6 amino acids from the N-terminal, expressed on the cytoplasmic side of the plasma membrane. Thus, the basis for 7E11.C5 specificity in imaging studies remains unclear. METHODS: Fluorescence-activated cell sorter (FACS) analysis of fixed and viable cultured cells was used to determine the staining intensity with FITC-labeled antibodies. RESULTS: The results indicate that FITC-labeled 7E11.C5 antibody is taken up and specifically labels viable LNCaP cells in vitro. Labeling intensity of viable cells after 2 hr of antibody incubation was similar to that of fixed cells. No labeling of cells that do not express PSMA was observed, nor was labeling observed with LNCaP cells treated with an isotype-matched irrelevant antibody. CONCLUSIONS: Uptake and labeling of PSMA by FITC-labeled 7E11.C5 in viable cells in vitro strongly suggest that this is a major basis for effectiveness of the 7E11.C5 antibody during in vivo imaging applications with 111In-labeled antibody (ProstaScint, Cyt-356).

Antibodies, Monoclonal↗

PubMed1996

Evaluation and comparison of two new prostate carcinoma markers. Free-prostate specific antigen and prostate specific membrane antigen.

BACKGROUND: Two new prostate cancer markers, free-prostate specific antigen (f-PSA) and prostate specific membrane antigen (PSMA) were recently introduced. This report summarizes a prospective two-year multicenter test of their diagnostic or prognostic capabilities. Total PSA was also measured. METHODS: There were four clinical groups studied: (1) 226 individuals from a screening project undergoing ultrasound and biopsy evaluation had markers obtained: (2) 68 patients suspected of having prostate cancer and undergoing 2 or more biopsies had the markers obtained on multiple occasions: (3) 100 patients undergoing radical prostatectomy had markers obtained pre- and post-operatively: and (4) 31 patients with metastatic prostate cancer each had multiple samples for marker assay obtained over a 2-year period. In all, 465 patients had one or more samples obtained and studied. RESULTS: Free-PSA affords little additional diagnostic advantage compared with total PSA in the screening population. The receiver operating characteristic curves for diagnostic accuracy were ranked: (1) PSA density; (2) total PSA; (3) f-PSA; and (4) PSMA, PSMA showed the best correlation with stage of the primary tumor in the screened group. In the multiple negative biopsy group, f-PSA varied from 12 to 21%. PSMA values were evaluated in all histologic categories. PSA density was > or = 0.15 in all categories. In the prostatectomy cases PSA values postoperatively were quite low in Stage II; f-PSA was of no value. Later, f-PSA was increased in association with elevated total PSA values. Mean PSMA values were above normal in all postoperative time periods except in Stage III patients at 6 months to 1 year postoperatively. PSA densities were all > or = 0.15. In patients with metastatic carcinoma, elevated PSMA values correlated best with a poor prognosis (clinical progression), as has been described. CONCLUSIONS: These data suggest that f-PSA values do not provide additional diagnostic benefit compared with total PSA in screening populations, in the presence of suspected cancer, postprostatectomy, or in metastatic disease. PSMA is of prognostic significance, especially in the presence of metastatic disease, and correlates well with the stage of disease in cancers detected in a screened population.

Antigens, Neoplasm↗

PubMed1996

Measurement of prostate-specific membrane antigen in the serum with a new antibody.

Work to date has identified prostate-specific membrane antigen (PSMA) as a membrane-bound glycoprotein with high specificity for prostatic epithelial cells. PSMA reacts with the monoclonal antibody 7E11.C5, which is present in serum, seminal fluid, and prostatic epithelial cells, and is increased in its expression in the presence of a hormone refractory state associated with prostatic cancer. This report confirms these results and further documents the presence of the monoclonal antibody 3F5.4G6, which reacts with the extracellular domain of PSMA. This region of PSMA is also an element present in a truncated version of the protein, so-called PSM'. Immune precipitation with either 7E11.C5 or 3F5.4G6 yields an isolated protein species that are reactive with the reciprocal antibody in Western blot analysis. Thus, 3F5.4G6 recognizes the same PSMA protein as does 7E11.C5, but at different epitopes on essentially opposite ends of the molecule. These two antibodies are well suited for use in a sandwich immunoassay, either one as a capture or detection antibody. Current work on this is underway. This report also confirms that 7E11.C5 Western blots for PSMA are negative with normal human brain tissue. The monoclonal antibody 9H10 does not react with 3F5.4G6 or with 7E11.C5 in studies conducted herein. Moreover, 3F5.4G6 reacts with PSMA found in the LNCaP cell line, but not DU-145 or PC3, which lack PSMA.

Amino Acid Sequence↗

PubMed1995

Comparison of prostate specific antigen, prostate specific membrane antigen, and LNCaP-based enzyme-linked immunosorbent assays in prostatic cancer patients and patients with benign prostatic enlargement.

Serum assays for prostate specific antigen (PSA; monoclonal), for prostate specific membrane antigen (PSM; Western blot), and a LNCaP/7E11.C5-based competitive enzyme-linked immunosorbent assay (ELISA) were evaluated in a small number of prostate cancer patients with localized or disseminated disease, and judged to be in clinical progression or remission based on National Prostate Cancer Project (NPCP) criteria. PSA values recognized the presence of clinical progression in localized disease (B1-C) and to a lesser degree disseminated disease (D1-D2). In contrast, to a limited degree the ELISA test recognized clinical progression mainly in disseminated disease and chiefly in stage D2. PSM values were elevated in both D1 and D2 but not in a linear fashion as observed with PSA. The ELISA and PSM results may be assessing a different clinical response to prostatic cancer than that recognized by PSA. This could reflect a developing clone of resistant prostatic cells as previously postulated. To further pursue this possibility a secondary generation of monoclonal antibodies to PSM is being developed. The ELISA levels for benign prostatic enlargement were not elevated above normal. In contrast both with PSA and PSM the assays reflected levels significantly above the normal range in benign prostatic hypertrophy (BPH).

Antibodies, Monoclonal↗

PubMed1994

Western blot assay for prostate-specific membrane antigen in serum of prostate cancer patients.

There is a need for the development of new diagnostic tools for the early detection of prostate cancer. A candidate molecule for a new screening test is a prostate-specific membrane antigen (PSM) recognized by the monoclonal antibody 7E11.C5. We carried out studies aimed at identifying PSM in the serum of normal and benign prostatic hyperplasia (BPH) donors and patients with adenocarcinoma of the prostate, in order to judge whether the development of a serum assay using this marker was feasible. By Western blotting, we found significant levels of PSM in serum samples from prostatic cancer patients, in the seminal fluid of pooled normal donors, in BPH patients, and in normal male sera. Similar to prostate-specific antigen (PSA), PSM was present in seminal plasma in higher concentrations than in serum, and PSM levels in prostatic cancer patients were significantly higher than in normal controls. These data suggest that the development of an assay utilizing the PSM and new monoclonal antibodies directed against the antigen, could provide a feasible test for prostatic cancers.

Adenocarcinoma↗