Current experience with radioimmunoassay techniques for prostatic acid phosphatase

Data are presented demonstrating that radioimmunoassay techniques for measurement of serum prostatic acid phosphatase are more sensitive than enzymatic methods in the detection of all stages of prostatic cancer. The possibility of using a solid phase RIA technique to screen for prostatic cancer is considered. Sixty-three hundred and twenty men over age 45 entering a clinical laboratory for any indication were evaluated using the RIA test for PAP. In this group 444 (7%) had elevated test values. Clinical recall and urologic review of the patients with elevated test results yielded 67 who were suspect for prostatic cancer, of whom 59 (88%) were confirmed by prostatic needle biopsy. These data suggest that the RIA for prostatic acid phosphatase as an isolated clinical procedure is not sufficiently specific to be used for screening due to the large number of false-positive results. However, the RIA-PAP test in combination with a follow-up urologic examination is quite specific and deserves further consideration as a screening method for prostatic malignancy.

Combined serum and bone marrow radioimmunoassays for prostatic acid phosphatase

Combined serum and bone marrow radioimmunoassays for prostatic acid phosphatase provide a unique means for the early diagnosis and more accurate clinical staging of prostatic cancer. The combined screening technique appears to be helpful, particularly in providing a clinical assessment of the presence or absence of early, subclinical lymphatic and bone marrow metastases. Low titer elevations of bone marrow prostatic acid phosphatase by radioimmunoassay have been observed commonly in clinically understaged C prostatic cancer with normal technetium bone scans, indicating the presence of unrecognized stage D disease with bone metastases. The combined screening method also is of distinct clinical value in the early diagnosis of prostatic cancer and in monitoring the effects of specific therapy. In therapeutically responsive patients marked suppression of serum and bone marrow prostatic acid phosphatase is observed regularly with the radioimmunochemical method under study.

A radioimmunoassay for prostatic acid phosphatase

A solid phase radioimmunoassay for human prostatic acid phosphatase has demonstrated substantially greater biochemical sensitivity than a standard enzymatic method for which p-nitrophenylphosphate was used as substrate. Preliminary data indicate that the radioimmunochemical approach can precisely classify 43% stage I-II and 94% stage III-IV prostate cancers. In contrast, the standard enzymatic methods correctly classified only 9% stage I-II and 46% stage III-IV cancers. It is clinically apparent that a radioimmunochemical approach for the measurement of human prostatic phosphatase may have distinct potential in the clinical diagnosis of prostate cancer.

Measurement of prostatic acid phosphatase in various cell lines

In the last few years, we have developed a radioimmunoassay for the measurement of human prostatic acid phosphatase. This method, which requires samples of the patient's serum, has been proved to be more accurate than the conventional enzymatic assay for the detection of early stages of carcinoma of the prostate. We used the enzymatic assay and radioimmunoassay for the quantitation of prostatic acid phosphatase in cultured prostatic cell lines. We were unable to show any difference in the concentration of prostatic acid phosphatase between prostatic and any other established cell lines.

Excessive proliferation of peripelvic fat of the kidney

Excessive proliferation of the peripelvic fat of the kidney (EPPF) is a benign process with an innocuous effect on the patient. However, this condition may assume major clinical significance by producing pyelocalyceal deformities that may be mistaken for true renal masses. Rarely, EPPF may masquerade as a renal pelvic tumor. We present the second reported case of EPPF simulating a renal pelvic tumor and review the history as well as the characteristic radiographic and sonographic features of this condition.

The natural history of papillary transitional cell carcinoma of the bladder and its treatment in an unselected population on the basis of histologic grading

Between 1950 and 1965, 365 patients were treated for transitional cancer of the bladder at our hospitals. A retrospective study was done, using clinical records and a histopathologic review to determine the long-term natural history of this population when treated conservatively. The natural history of 3 separate patient populations was discovered, based solely on the grading of the transurethrally resected fragments. Based on the grade on initial presentation these patients were divided into grades I, II and III. Of the patients 5 per cent in grade I, 16 per cent in grade II, 28 to 35 per cent in grade III not involving muscle and 83 per cent in grade III involving muscle died of bladder cancer. Ninety-seven patients (26 per cent) died of bladder cancer, 110 (31 per cent) died of other causes and 158 (43 per cent) have been alive more than 5 years (104 more than 10 years). Grade I tumors that progressed to a higher grade did so within 2 years of the initial diagnosis. Of the bladder cancer deaths 83 per cent occurred within 2 years of the initial diagnosis. Of 64 patients dying more than 5 years after presentation only 7 died of bladder cancer.

A solid phase radioimmunoassay for prostatic acid phosphatase

The sensitivity of a recently developed solid phase radioimmunoassay for human prostatic acid phosphatase was compared to that of an enzymatic method using p-nitrophenylphosphate as substrate. In 109 histologically verified untreated stages I to IV prostatic cancers and 200 men without such cancer the solid phase radioimmunoassay method demonstrated substantially greater sensitivity and specificity than the enzymatic technique. In the 109 prostatic malignancies the immunochemical method correctly classified 80 (73 per cent) versus 34 (31 per cent) for the p-nitrophenylphosphate enzymatic technique (p less than 10(-6). In 44 stages I and II cancers confined to the prostate the radioimmunoassay was abnormally elevated in 19 (43 per cent) with only 4 (9.1 per cent) enzymatic elevations (p less than 10(-3). In 65 stages III and IV extraprostatic cancers correct classifications were noted in 61 (94 per cent) of the radioimmunoassays and 30 (46 per cent) enzymatic tests (p less than 10(-6). The radioimmunoassay in 200 male controls yielded 11 (5.6 per cent) and the p-nitrophenylphosphate enzymatic test yielded 7 (3.5 per cent) falsely positive results. In 90 non-prostatic human cancer sera 85 (94.5 per cent) were correctly classified as negative by the radioimmunoassay for prostatic acid phosphatase versus 66 (73 per cent) as negative by the enzymatic method. These data are discussed in terms of the merits of a radioimmunochemical approach for the measurement of human serum prostatic acid phosphatase.

Experimental use of fluoroalkyl cyanoacrilate in ureteral anastomosis

A fluorinated tissue adhesive Fluoroalkyl Cyanoacrilate has been used in end-to-end ureteral anastomoses as an adjunct to suture material to avoid urinary extravasation in seven dogs. A similar number of dogs served as controls. The urinary tracts were evaluated grossly, radiographically, and histologically after 3 to 12 months. Better anatomical results and less inflammatory reaction and fibrosis were found in the group submitted to the tissue adhesive.

Radioimmunochemical measurement of bone marrow prostatic acid phosphatase

Human acid phosphatases are ubiquitous phosphohydrolases that are present in most respiring tissues and cells. Specifically, human prostatic acid phosphatase is a unique enzyme within a vast family of acid phosphatases concerned with catabolic processes in cellular metabolism. The majority of serum and bone marrow acid phosphatases are of non-prostatic origin and are present chiefly in erythrocytes, leukocytes, platelets and other maturing cells in the bone marrow. The specific concentration of prostatic acid phosphatase in serum and bone marrow is normally relatively low compared to non-prostatic acid phosphatases. Many falsely positive assays for total serum acid phosphatases and bone marrow acid phosphatases have been reported, particularly after traumatic marrow biopsy procedures and mishandling of blood samples in the clinical laboratory and in hematologic disease states. The disruption and lysis of whole blood and marrow cells can liberate non-specific acid phosphatases into the serum. Since standard enzymatic assays do not discriminate accurately prostatic acid phosphatase from non-prostatic acid phosphatase present in the serum spurious results can be realized. A preliminary experience with a promising radioimmunoassay for the specific measurement of prostatic acid phosphatase in bone marrow and serum is presented.

Counterimmunoelectrophoresis in determination of prostatic acid phosphatase in human serum

We evaluated counterimmunoelectrophoresis for use in measuring prostatic acid phosphatase in detection of prostatic cancer. After staining for acid phosphatase, we could detect as little as 0.3 ng of purified enzyme standard complexed with antibody by this technique. However, when serum samples were used as antigen, the method was less sensitive (1.5-2.0 ng) because some of the serum proteins migrate with the phosphatase and decrease the intensity of the stain for acid phosphatase. For this reason we could not detect the phosphatase in serum samples of normal persons; only patients with moderately (or greater) increased activity in their serum showed positive results. In contrast, by radioimmunoassay as little as 1.0 ng of the phosphatase can be detected in serum.

Counterimmunoelectrophoresis in determination of prostatic acid phosphatase in human serum

We evaluated counterimmunoelectrophoresis for use in measuring prostatic acid phosphatase in detection of prostatic cancer. After staining for acid phosphatase, we could detect as little as 0.3 ng of purified enzyme standard complexed with antibody by this technique. However, when serum samples were used as antigen, the method was less sensitive (1.5-2.0 ng) because some of the serum proteins migrate with the phosphatase and decrease the intensity of the stain for acid phosphatase. For this reason we could not detect the phosphatase in serum samples of normal persons; only patients with moderately (or greater) increased activity in their serum showed positive results. In contrast, by radioimmunoassay as little as 1.0 ng of the phosphatase can be detected in serum.

Detection of prostatic cancer by solid-phase radioimmunoassay of serum prostatic acid phosphatase

We compared our radioimmunoassay with the standard enzyme assay for prostatic acid phosphatase in the diagnosis of prostatic cancer. Serum samples from 50 controls, 113 patients with prostatic cancer, 36 with benign prostatic hyperplasia, 83 with other cancers, 20 with gastrointestinal disorders and 28 with total prostatectomies were randomized and studied by radioimmunoassay and enzyme assay. When the upper limit was set at 8.0 ng per milliliter (mean + 4 S.D.) the radioimmunoassay diagnosed prostatic cancer in 33, 79, 71 and 92 per cent of the patients with Stage I, II, III and IV disease. In contrast, the enzyme assay detected elevations of enzyme in the serum of 12, 15, 29, and 60 per cent respectively. No false-positive results were detected by either assay in normal controls but the radioimmunoassay test was positive in two patients with benign prostatic hyperplasia, in one patient after total prostatectomy, in nine with other cancers and in one of the group with gastrointestinal disorders. In contrast to the enzyme assay, the radioimmunoassay distinguished over half the cases of intracapsular prostatic cancer.

Isozymes of acid phosphatase in normal and cancerous human prostatic tissue

The supernatants of the homogenates from normal and cancerous human prostatic tissue run on polyacrylamide gel electrophoresis have 2 major electrophoretic bands when stained for prostatic acid phosphatase. The ratios of the electrophoretically distinguishable isoenzymes differ in normal and cancerous tissues. Similar distinctions between isoenzymes in normal and cancerous prostates are observed following column chromatographic separation or isoelectric focusing. The faster electrophoretic band can be separated by diethylaminoethyl cellulose column chromatography or by isoelectric focusing into at least five fractions with different electrophoretic mobilities. We could not find any differences in normal and cancerous tissues among these subfractions of the faster-moving electrophoretic band. Analysis by gel electrophoresis does not show association between these fractions after chromatographic or isoelectric separation of the prostatic acid phosphatase fractions. Quantitative, but no qualitative, differences in prostatic acid phosphatase isozymes occur in normal versus cancerous prostates.

Gamma A myeloma with hyperviscosity and obstructive uropathy

A patient with gamma A myeloma, hyperviscosity and an obstructive uropathy is described. Operation revealed a proteinaceous mass obstructing the right renal pelvis. Immunoprecipitin and immunofluorescent analysis of this mass and concentrated urine demonstrated the presence of gamma A myeloma protein, kappa light chains and albumin. This is the first description of an obstructive uropathy in multiple myeloma owing to a proteinaceous matrix containing paraprotein.

Comparison of human prostatic acid phosphatase by measurement of enzymatic activity and by radioimmunoassay

We compared results of measurement of prostatic acid phosphatase activity in serum and various tissues by enzymatic assay and radioimmunoassay. By enzymatic assay, activity in serum is lost rapidly, even at room temperature. In contrast, there was no change in antigenic activity during 48 h by radioimmunoassay. The radioimmunoassay was more specific in 12 tissues and in serum than were several enzymatic assays that make use of inhibitors of the enzyme. The enzymatic assay resulted in 26.6% (24/90) false positives from non-prostatic cancer patients. In contrast, with radioimmunoassay there were only 5.5% (5/90) false positives. We conclude that immunological detection of prostatic acid phosphatase is the more reliable technique.

Comparison of human prostatic acid phosphatase by measurement of enzymatic activity and by radioimmunoassay

We compared results of measurement of prostatic acid phosphatase activity in serum and various tissues by enzymatic assay and radioimmunoassay. By enzymatic assay, activity in serum is lost rapidly, even at room temperature. In contrast, there was no change in antigenic activity during 48 h by radioimmunoassay. The radioimmunoassay was more specific in 12 tissues and in serum than were several enzymatic assays that make use of inhibitors of the enzyme. The enzymatic assay resulted in 26.6% (24/90) false positives from non-prostatic cancer patients. In contrast, with radioimmunoassay there were only 5.5% (5/90) false positives. We conclude that immunological detection of prostatic acid phosphatase is the more reliable technique.

Production of specific antibody to purified prostatic acid phosphatase

Prostatic acid phosphatase may well be a prime antigenic protein in prostatic tissue and fluid. Extraction of the enzyme in highly purified form from prostatic fluid and benign hypertrophic prostatic tissue provides a unique antigen capable of inducing a prompt and specific antibody response in the goat and rabbit as amnifested by immunodiffusion, immunoelectrophoresis, and immunofluorescence techniques. In prostatic cancer patients with elevated serum acid phosphatase levels it is possible to detect humoral circulating PAP antigen by standard immunoelectrophoretic methods and to confirm the existence of the enzyme by radioautography, L-tartrate inhibition, and the Gomori or Burstone staining procedures. Preliminary indirect prostatic immunofluorescence studies consistently demonstrated characteristic fluorescent foci in the paranuclear areas of benign prostatic epithelial cells, the presumed area of synthesis of prostatic acid phosphatase. Consideration has been given to the possibility of the development of a radioimmunoassay for prostatic acid phosphataase utilizing a heterolologous antiserum to the enzyme extracted from human prostatic fluid.

Enhancing effect of surfactant and protein on hydrolysis of thymolphthalein monophosphate by purified prostatic acid phosphatase

Purified prostatic acid phosphatase catalyzes the hydrolysis of thymolphthalein monophosphate 10-fold faster if an optimal concentration of Brij 35 (a wetting agent) or protein (bovine serum albumin or human serum proteins) is present. Results of gel filtration, dialysis, and sucrose density-gradient centrifugation analysis suggest that the substrate must combine with detergent or protein before the enzyme can catalyze its hydrolysis.

A solid-phase radioimmunoassay for human prostatic acid phosphatase

A solid-phase technique for radioimmunoassay of human prostatic acid phosphatase (EC 3.1.3.2) is described. Human prostatic acid phosphatase was purified from prostatic fluid. Monospecific antisera to the purified acid phosphatase were produced in rabbits. Disposable polypropylene tubes were coated with antiserum and used for radioimmunoassay with 125I-acid phosphatase. The nonspecific binding was minimized by saturating the binding sites of the tubes with bovine serum albumin. The working range of the technique was 1 to 30 ng of antigen. The solid-phase radioimmunoassay is rapid, sensitive, and efficient. In preliminary clinical trials it was shown that (a) patients with advanced prostatic cancer had elevated prostatic acid phosphatase levels by both enzymatic assay and radioimmunoassay assays, and (b) patients with other cancers were in the normal range for prostatic acid phosphatase.

Endotoxin as a cause of aseptic meningitis after radionuclide cisternography

The role of pyrogens in aseptic meningitis after radionuclide cisternography was studied by means of the Limulus test, a sensitive detector of endotoxin. During a 15-month period, 39 reactions associated with cisternography were reported. Ten samples of specific lots of the radioactive drugs implicated in 20 of these reactions were tested and all reacted strongly positive to the Limulus test. The less sensitive rabbit pyrogen test was negative for these preparations when tested on a dose-per-weight basis. Our findings apparently provide clinical evidence for the observation made in animals that endotoxin is at least 1,000 times more toxic intrathecally than intravenously. The data implicate endotoxin contamination as a cause of adverse reactions to radionuclide cisternography. We conclude that the USP pyrogen test is insufficiently sensitive for intrathecal injectables and should be supplemented by the Limulus test.