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R M Loor

Publications and source records attributed to R M Loor.

11 recordsLinked to original sources
PubMed1982

Multiple marker evaluation in human prostate cancer with the use of tissue-specific antigens.

Serum prostate-specific antigen and prostatic acid phosphatase were simultaneously evaluated in 22 healthy males, 29 patients with benign prostatic hypertrophy, and 192 patients with prostate cancers at various stages as well as in 30 patients with cancers other than prostate cancer. Both markers were quantitated by specific sandwich-type, enzyme-linked, immunosorbent assays with the use of specific antiserum reagents. Serum assays revealed a discordance between these two markers; thus expressions of these two biochemically and immunologically distinct prostate-specific proteins may reflect different aspects in the biology of prostate cancer. A combination test with the use of 7.5 ng of prostate antigen and 15.5 ng of prostatic acid phosphatase/ml of serum, respectively, as cutoff values resulted in a positive detection rate of 58% for prostate cancers of stages A (7/12) and B (21/36) each, 68% for prostate cancer of stage C (19/28), 92% for prostate cancer of stage D (106/116), and only 10% for benign prostatic hypertrophy (3/29). None of 52 other cancers or healthy controls was registered as positive. This study demonstrates that a multiple marker test of tissue-specific antigens can be of an additive value in the immunodiagnosis of cancer and may be a logical and effective approach at this time, in light of the unavailability of human tumor-specific markers.

Acid Phosphatase↗
PubMed1981

Isolation, characterization and clinical evaluation of a pancreas cancer-associated antigen.

A pancreas cancer-associated antigen (PCAA) was identified and isolated from ascites fluid of human pancreatic cancer. Purified PCAA was homogeneous as determined by polyacrylamide gel electrophoresis. PCAA was a glycoprotein with a molecular weight of approximately 1,000,000 and consisted of 20% carbohydrates and 80% peptides, had an isoelectric point of 4.7, and migrated to alpha 2-beta region. It possessed a sedimentation coefficient of 14S and appeared to be a fibrous or fibroglobular protein. Immunoreactivity of PCAA was sensitive to proteolytic enzymes, perchloric acid, KSCN, glycine-HCl at pH 2.5, urea and lithium diiodosalicylate; and insensitive to neuraminidase or beta-glucosidase. Immunohistochemical technique revealed that PCAA was located in the cytoplasm of ductal epithelial cells of malignant pancreas. Using heteroantiserum raised against purified PCAA, horseradish peroxidase and CNBr-activated Sepharose 4B, an enzyme-immunoassay (EIA) for circulating PCAA has been developed. From a group of 40 healthy blood donors, an upper limit of 16.2 micrograms of PCAA/ml of serum has been tentatively determined. An elevated PCAA was shown in 67% (29/43) of patients with pancreas cancer, as well as in 30% (11/36) of lung cancer patients, 27% (10/37) of colonic cancer patients, and in 16% (6/36) of breast cancer patients. The reactive antigen in sera of these cancers was shown to be immunologically identical. PCAA also was detected in extracts of various human tissues, particularly pancreatic tumors, colonic tumors, and in a normal colon. Further, PCAA exhibited heterogeneity in molecular weight, isoelectric point, and electrophoretic mobility.

Animals↗