Biomedical subjects

E W Arfman

Publications and source records attributed to E W Arfman.

7 recordsLinked to original sources

PubMed1998

A novel monoclonal antibody 107-1A4 with high prostate specificity: generation, characterization of antigen expression, and targeting of human prostate cancer xenografts.

Monoclonal antibodies with high specificity for prostate tissue are of interest for prostate cancer research and treatment. Reactivity and specificity of a new murine monoclonal antibody, 107-1A4, was assessed by immunohistochemistry, ELISA and indirect immunofluorescence (IDIF). 107-1A4 stained all normal and malignant prostate tissue specimens while reactivity to non-prostate tissue was limited to the tubules of the normal kidney and renal cell carcinoma. Twenty two human cell lines were included in the reactivity survey; only the immunogen prostate cancer line LNCaP reacted with 107-1A4. Seminal plasma proteins PSA, PAP, PSMA, and PSP-94 were determined not to be the 107-1A4 antigen.

Journal Article↗

PubMed1998

The value of a reverse transcriptase polymerase chain reaction assay in preoperative staging and followup of patients with prostate cancer.

PURPOSE: The reverse transcriptase polymerase chain reaction (RT-PCR) assay is an extremely sensitive technique of detecting cells expressing prostate specific antigen (PSA). Controversy exists regarding the ability of peripheral blood PSA RT-PCR testing to reflect pathological staging or treatment outcome. We examine the phenomenology of RT-PCR results in patients with prostate cancer, with particular emphasis on the RT-PCR test before and after radical prostatectomy, and correlations with pathological staging and treatment outcome. MATERIALS AND METHODS: Peripheral blood was obtained from a wide variety of patients with and without prostate cancer, including before and after radical prostatectomy. After ribonucleic acid isolation, complementary deoxyribonucleic acid was generated and amplified with a hot-start technique. RT-PCR results were compared with pathological stage, Gleason score, tumor volume and disease-free status. Correlations between preoperative and postoperative RT-PCR tests were also made. RESULTS: The RT-PCR test was positive in 1 of 56 controls (1.8%) without suspicion of prostate cancer. A positive test was obtained in 12 of 65 men (18.5%) with a suspicion of prostate cancer but a negative biopsy. Before radical prostatectomy a positive test was obtained in 13 of 75 men (17.3%) with pT2 disease versus 10 of 46 (21.7%) with pT3 disease. There was no significant difference in serum PSA, Gleason score or tumor volume between the men with positive or negative results. With repetitive testing an increasing percentage of men had at least 1 positive test preoperatively. With a median followup of 8 months 6 of the 7 patients in whom radical prostatectomy failed had had negative RT-PCR before treatment. Of patients with known metastatic disease or failed primary treatment a positive test was obtained in 32 to 75%. Radical prostatectomy and prostate needle biopsy appeared to have a negligible effect on RT-PCR tests immediately following these procedures. Following radical prostatectomy results were variable but many men who are RT-PCR positive preoperatively become RT-PCR negative postoperatively. CONCLUSIONS: The PSA RT-PCR test in our laboratory cannot be used preoperatively to predict pathological stage of prostate cancer or treatment failure. Most cases that are positive preoperatively become negative postoperatively. While increasing tumor burden increases the likelihood of positive tests, there appears to be significant sampling error associated with the use of this test in the peripheral blood.

Adult↗

PubMed1997

Characterization of 10 new monoclonal antibodies against prostate-specific antigen by analysis of affinity, specificity and function in sandwich assays.

While prostate-specific antigen (PSA) is already an invaluable marker for prostate cancer, there is continuing demand for new anti-PSA antibodies with specific characteristics, e.g., high sensitivity and specificity and equimolar binding to free PSA (f-PSA) and the PSA-alpha-1-antichymotrypsin complex (PSA-ACT), as well as the ability to distinguish between these 2 immunoreactive forms of PSA. We have therefore generated and characterized 10 anti-PSA monoclonal antibodies (MAbs). Apparent dissociation constants (Kd) of MAbs were determined by direct ELISA yielding Kd-0.2-164.0 nM. Western blots suggested that 3 of the MAbs (60-1A2, 60-8A2 and 17-1A2) bind to linear epitopes. Sandwich assays identified 5 major antigenic regions as binding targets of the MAbs. Three combinations of MAbs recognize f-PSA and PSA-ACT in equimolar fashion with high sensitivity. Two of the MAb combinations are specific for f-PSA. Physical analysis of the new antibodies has allowed us to assign the MAbs to binding classes (based on their sandwiching capabilities) and to determine accurate apparent dissociation constants.

Animals↗

PubMed1997

Detection of circulating prostate cells by reverse transcriptase-polymerase chain reaction of human glandular kallikrein (hK2) and prostate-specific antigen (PSA) messages.

OBJECTIVES: To investigate the clinical value of human glandular kallikrein (hK2) reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of prostate cells in circulation and to compare the results with those obtained from prostate-specific antigen (PSA) RT-PCR. METHODS: We examined peripheral blood (PB) and bone marrow (BM) samples of 13 patients with advanced-stage prostate cancer and 63 patients with clinically localized disease for the presence of circulating prostate cells. An RT-PCR protocol with a two-step amplification cycle and hot-start conditions was used. RESULTS: The limit of detection of the PCR portion is similar for PSA and hK2 (5 to 10 copies of the plasmid containing the cDNA). The RT-PCR limit of detection is one LNCaP cell in 10(8) peripheral blood mononuclear cells (PMBC) for PSA, and one LNCaP cell in 10(7) PMBC for hK2. Of the BM samples obtained prior to radical prostatectomy, 71.4% were positive for PSA mRNA and 41.3% were positive for hK2 mRNA. In PB, the PSA positivity was 19% and hK2 positivity 12.7%. In advanced-stage patients, there were 76.9% PSA-positive samples in BM versus 38.5% hK2-positive samples; 46.2% of patients were positive in PB for PSA versus 30.8% for hK2. CONCLUSIONS: We have developed a sensitive RT-PCR protocol for detection of hK2 mRNA and evaluated the suitability of hK2 mRNA in comparison with PSA mRNA as an additional marker for detection of prostate cells in circulation. Combining results of these two tests increased the sensitivity of detection.

Humans↗

PubMed1997

Improved reverse transcriptase-polymerase chain reaction protocol with exogenous internal competitive control for prostate-specific antigen mRNA in blood and bone marrow.

The possibility of improving diagnosis of micrometastases from prostate cancer by further enhancing the detection of prostate-specific antigen-producing cells in circulation is being evaluated. We have developed a reverse transcriptase-PCR protocol with the desirable characteristics of low limit of detection, high specificity, reproducibility of response, and ease of performance. Among the procedural alterations that have contributed to these improvements are longer PCR primers, a two-step amplification cycle, and hot-start PCR. We have lowered the limit of detection to one LNCaP prostate-cancer cell in 10(8) peripheral blood mononuclear cells, and samples of blood and bone marrow from healthy donors have yielded no false positives. Because PCR procedures frequently exhibit tube-to-tube variability, we have incorporated a set of internal and external controls into the protocol-a significant advance in assuring assay reliability.

Bone Marrow↗

PubMed1988

Monoclonal antibody-targeted radiotherapy of renal cell carcinoma using a nude mouse model.

Radiation dosimetry and monoclonal antibody (MAB)-targeted radiotherapy studies were performed to evaluate the feasibility of using tumor-preferential MAB as targeting agents for internal radiotherapy of renal cell carcinoma (RCC). Two human RCC xenograft lines, TK-177G and TK-82, were established in nude mice and studied using MAB A6H as a targeting agent. This MAB has previously demonstrated excellent in vivo localization to RCC xenografts. Two doses of A6H (13 to 19 micrograms) labeled with iodine 131 (110 to 130 microCi) caused the tumor to regress or arrested the tumor growth in both xenografts. Similar doses (18 to 43 micrograms; 120 microCi) of 131I-labeled control MAB AFP-22 or of unlabeled A6H did not inhibit tumor growth. While most mice in the control groups had tumors greater than 250 mg in weight by day 43, none of the tumors in mice treated with 131I-labeled A6H grew to that size during the 3-month observation period. Sequential computerized scintigraphy was used to calculate the amount of radioisotope localized in tumor versus normal mouse tissue. Therapeutic doses of 131I-labeled A6H delivered a median calculated radiation dose of 38 cGy/microCi (range, 28 to 57) injected dose to RCC xenografts, and a median of 0.9 cGy/microCi to normal mouse tissues. These findings suggest that A6H is able to target radioisotopes highly specifically to RCC and achieve a therapeutic effect in the experimental setting.

Animals↗

PubMed1985

Monoclonal antibodies to human renal cell carcinoma: recognition of shared and restricted tissue antigens.

Monoclonal antibodies (MABs) reactive with human renal cell carcinoma (RCC) were generated following immunization of mice with either RCC homogenates, RCC cell lines, or fetal kidney homogenates. The characteristics of four highly reactive immunoglobulin G1 MABs, designated UMVA-RCC-A6H, UMVA-RCC-A36, UMVA-RCC-C5H and UMVA-RCC-D5D are presented. The screening process consisted of a cell binding enzyme-linked immunosorbent assay and immunohistological examination of tumor, normal, and fetal tissue sections. The MABs illustrated various degrees of antigen restriction: A6H identified an antigen common to RCC, some lung and colon carcinomas, the proximal renal tubules but no other normal tissues; A36 reacted with most human tumors, the renal tubules, and many other normal tissues; C5H reacted with nearly every human cancer but of the normal tissues, only the renal glomerulus shared this antigen; D5D was very restrictive, reacting with many although not all RCC and no other cancers or normal tissues with the exception of an occasional reactivity with a Bowman's capsule. Metastatic RCC and RCC xenografts expressed these antigens. None of the MABs participated in complement-mediated cytotoxicity. In immunoprecipitation studies with L-[methyl-3H]methionine and [3H]glucosamine-HCl metabolically labeled RCC cells, C5H was shown to be associated with an antigen of Mr 115,000.

Animals↗