Two new, direct, and specific methods of acid phosphatase determination. National field trial

Trial of specific antigen-mediated leukocyte adherence inhibition test in patients with chronic active hepatitis and hepatitis B carrier

In the pathogenesis of chronic active hepatitis, the importance of cell mediated immunity (CMI) has been emphasized. Leukocyte adherence inhibition (LAI) assay, which is one of the methods for analysis of the reaction of CMI, has been used to analysie the CMI of cancer patients.

The authors tried the specific antigen-mediated LAI assay in 40 patients with chronic active hepatitis, 19 patients carriers of hepatitis B virus, and in the 5 persons who have no anti-HBs in spite of receiving vaccination against HBV, and these were compared with 7 normal control subjects who had been exposed to hepatitis B virus previously.

The results were as follows: The NAI was 52.4±14 (mean ± standard deviation) in 7 normal control subjects who had been exposed to hepatitis B virus previously. The NAI was 20.6 ± 11 (mean ± standard deviation) in 40 patients with chronic active hepatitis. The value was significantly lower than that of the normal control group (P<0.001). The NAI was 49.7±17.8 (mean ± standard deviation) in 19 patients carriers of hepatitis B virus. The value was not significantly different from that of the normal control group (P>0.05). The NAI was 25.1±11 (mean ± standard deviation) in 5 persons who have no anti-HBs in spite of receiving vaccination against HBV. The value was significantly lower than that of the normal control group (P<0.05). In patients with chronic active hepatitis and hepatitis B virus carriers, we checked the LAI assay serially. The value of NAI was increased according to the improvement of clinical symptoms and normalization of transaminase, but the value of NAI was decreased according to the worsening of clinical symptoms and elevation of transaminase.

Circulating prostatic acid phosphatase-immunoglobulin complexes in Sjogren's syndrome

Elevated level of serum prostatic acid phosphatase (PAP) activity in a patient with Sjogren's syndrome was found to be due to the presence of PAP-immunoglobulin complexes in circulation. The patient did not have a prostatic malignancy. The complexes were demonstrated by counter-immunoelectrophoresis, protein A-Sepharose immunoprecipitation and agarose-gel electrophoresis. Free enzyme was not detected in serum, and the activity of the complexed enzyme was probably unaltered on binding with the immunoglobulins.

Tumor markers: value and limitations in the management of cancer patients

Sixteen tumor markers are reviewed, and measured to the ideal: produced by the tumor cell alone absent in health and in benign disease present in all patients with a given malignancy level in the blood representative of tumor mass detectable in occult disease. The only marker that approaches the ideal is human chorionic gonadotropin (HCG) in gestational trophoblastic tumors. In this malignancy, the HCG level suggests the diagnosis and stage, confirms response to therapy, and predicts relapse. The three most widely used and intensely studied tumor markers are carcinoembryonic antigen (CEA), alphafetoprotein (AFP), and HCG. CEA cannot be used in screening for cancer, but in carcinoma of the colon its elevation preoperatively increases the likelihood of advanced disease and postoperative recurrence. Postoperatively, elevated titers are often but not invariably associated with recurrent disease. AFP and HCG are useful in the management of nonseminomatous germ cell testicular tumors. Like CEA, they cannot be used for screening. They are more likely to be increased with advancing stage, and after therapy rising levels almost always mean recurrent disease. Some markers are valuable in specific circumstances, such as calcitonin in screening for familial medullary carcinoma of the thyroid. In multiple myeloma, immunoglobulins are useful in determining the tumor mass and response to therapy. In neuroblastoma, catecholamine metabolites are useful primarily in making the diagnosis. In some malignancies, the absence of effective therapy lowers the value of the marker, as for AFP in hepatoma. The remaining markers are too unreliable or too little studied to be useful in the management of an individual patient with cancer. The purpose of this paper is to provide the clinician with an understanding of the limitations of the present tumor markers that will lead to wiser use of the tests, and to provide standards to which future tumor markers should be measured.

Radioimmunoassay for prostatic acid phosphatase in early prostatic carcinoma

A radioimmunoassay procedure has been used to measure prostatic acid phosphatase in the serum of 46 patients with intracapsular carcinoma of the prostate. The results obtained did not differ significantly from those obtained in a control group of similar size. It is concluded that the radioimmunoassay procedure for measurement of prostatic acid phosphatase has no advantage over enzyme activity measurements for the detection of early prostatic carcinoma.

The stability of prostatic acid phosphatase, as measured by a capture immunoenzyme assay

A capture immunoenzyme assay (CIEA) for prostatic acid phosphatase (PAP) was developed and used to study the stability of this isoenzyme. Immunospecifically purified goat antibodies to PAP were covalently bound to special discs and used to capture the enzyme in serum samples in a weakly acidic medium during the first incubation (2 h) at 37 degrees C. The capture enzyme was then measured by its catalytic activity with p-nitrophenyl phosphate as substrate during the second incubation (1 h) at 37 degrees C. As much as 98% of the PAP in test specimens was captured and measured by this CIEA. The test results were expressed as enzymatic activity (U/l), extrapolated from a standard curve which was linear between 0.026 and 70 U/l. In test sera stored at 4 degrees C, the PAP was variably stable for 7 to 70 days, but the enzyme was quite stable in serum when stored at -20 degrees C for at least 156 days. At room temperature, when the sera were appropriately acidified, there was no loss of enzymatic activity for periods of 15 days, and in some cases, a large proportion of activity was still intact after 70 days. At 4 degrees C, as well as -20 degrees C, acidified serum and the partially purified PAP standard showed complete stability for at least 7 months. The CIEA reactivity of positive test specimens was inhibited by L(+)-tartaric acid, but not by cupric sulfate. The acid phosphatases of blood cell extracts were non-reactive in the CIEA procedure. The CIEA results of 224 serum samples from patients with and without prostate cancer correlated very well with those obtained by two direct enzymatic and two commercial RIA procedures, with correlation coefficients between 0.960 and 0.993, and diagnostic agreement between 86% and 100%.

Perspectives on serum acid phosphatase in prostatic disease. An evaluation of two methods

Acid phosphatase in serum was measured in 116 patients with prostatic disease, benign in 59 and malignant in 57 cases. Comparisons were made between radioimmunoassay (RIA) and an enzymatic method. The correlation coefficient between the respective values was 0.96 in patients with untreated prostatic cancer, indicating that no significant difference between results with the two methods was to be expected. The correlation coefficient between RIA values and cancer stage was 0.48, and between catalytic activity and cancer stage it was 0.50. The validity of the two methods consequently was equal. RIA, however, was the more sensitive method, giving elevated values in 10 of 11 patients with untreated stage III or stage IV prostatic cancer, as compared with only 4 of the same 11 in the enzymatic assay. This seeming paradox most probably was attributable to differing intrinsic properties of the methods when the upper limits of normal range were established. Neither RIA nor enzymatic analysis discriminated early prostatic cancer (stages I and II) from benign lesions.

The laboratory diagnosis of prostatic adenocarcinoma

At the close of each decade, we are reminded by medical statisticians that our longevity increases significantly. For the male, especially if he be of black race this statement has an ironic twist. Over age 70, prostatic "cancer" assumes the leadership list of "cancers" in general, supplanting lung and colo-rectal. One interesting point evolved by careful autopsy studies suggests that this incidence is found coincidentally and is not primarily responsible for the cause of death. This illustrates a different significance to other neoplasia, and offers useful opportunities to study the evolution of a neoplasm. In contrast to other "cancers" (for example pulmonary), the histological nature of the tumor is almost totally derived from the acinar lobules and designated adenocarcinoma. Neoplasia arising from the fibromuscular stroma (sarcoma) and metaplastic ductus (squamous cell carcinoma) constitute less than 1% of all prostate cancers. Histological appearances, however, are not as simple as hoped. As in many tumors the section may present a uniform well-differentiated adenocarcinoma in which the acinar structure is well maintained--yet at the opposing end of the spectrum show a fatally dedifferentiated picture whose organ origin is difficult to determine. Adding to the complication is the wide variation, far more commonly seen, of the mixed tumor with all variations presenting a composite panorama of histology. Indeed the pure type is rare. As with all neoplastic disease, early detection is critical, since opportunity for cure with the various forms of therapy from surgery through radiation to chemotherapy are increasing rapidly. The prostate gland is relatively accessible to the trained finger of the physician and later stages of the disease are palpable. However, the earliest Stage (I) is not discovered by rectal examination, hence provides an ideal opportunity for the serum tumor marker, to identify disease. Since 1938, disseminated prostatic adenocarcinoma has been associated with elevation of activity of an enzyme acid phosphatase. Although there are several isoenzymes the prostatic specific one has in the past been assayed by different spectrophotometric techniques using selective substrate and chemical inhibition. More recently various immunological methods have added a greater sensitivity and specificity to the early detection of prostatic adenocarcinoma. However is should be clearly stated that prostatic acid phosphatase is not cancer specific and can be associated with other nonmalignant lesions in the prostate gland.(ABSTRACT TRUNCATED AT 400 WORDS)

A critical evaluation of a specific radioimmunoassay for prostatic acid phosphatase

A radioimmunoassay (RIA) method for acid phosphatase detection was compared to a standard enzyme assay using sera from 210 normal volunteers and 285 patients with prostatic disease. Statistical and clinical comparisons were made between defined subgroups. All 55 normal females had RIA detectable serum acid phosphatase, implying that this assay cannot be entirely specific for enzyme of prostatic origin. Urinary catheterization did not affect acid phosphatase levels. In all stages of carcinoma there were more acid phosphatase elevations by the RIA method than enzyme method, but neither assay could differentiate intracapsular cancer from benign prostatic hyperplasia. A small number of patients with biopsy proven negative nodules had marginally elevated values, suggesting as obligation for closer follow-up. The RIA method may be superior for monitoring patients with more advanced malignancy. Additional practical advantages of the RIA include relative simplicity and elimination of the special serum handling required for the enzyme assay.

Radioimmunoassayable prostate-specific acid phosphatase in peripheral and bone marrow sera compared in diagnosis of prostatic cancer patients

Measurements of human prostate-specific acid phosphatase by radioimmunoassay in peripheral and bone marrow sera were compared. We studied 20 patients with benign prostatic hyperplasia, 27 with untreated prostatic cancer without bone metastases and 11 with metastases, in addition to 7 with cancer treated by hormonal therapy. The prostate-specific acid phosphatase concentrations in peripheral and bone marrow serum samples were equal and did not exceed the upper limit of our health-associated reference interval, 2.8 microgram. per 1. (mean plus 2 standard deviations) in patients with prostatic hyperplasia. Of 27 prostatic cancer patients without bone metastases the concentration of prostate-specific acid phosphatase was elevated in the peripheral sera of 20 and in the bone marrow sera of 21, and 21 had an extracapsular tumor (stage T3 to T4). Prostate-specific acid phosphatase concentrations were elevated in peripheral and bone marrow serum specimens of all 11 patients with metastases and bone marrow cytology studies were positive in 2. There was no difference in prostate-specific acid phosphatase concentrations in peripheral and bone marrow serum specimens from prostatic cancer patients undergoing hormonal treatment. We conclude that the use of bone marrow serum for the measurement of radioimmunoassayable prostate-specific acid phosphatase in prostatic cancer patients does not provide any further information in regard to the detection of prostatic cancer compared to the use of peripheral serum specimens. Falsely positive findings in bone marrow specimens were not observed with the method used.

Radioimmunoassay versus counterimmune electrophoresis for measurement of serum prostatic acid phosphatase

Radioimmunoassay (RIA) kits obtained from commercial sources were evaluated and compared with a standard counterimmunoelectrophoretic (CIE) assay for the measurement of prostatic acid phosphatase (PAP) in serum. None of the radioimmunoassays was found to be more sensitive than the CIE assay in detecting elevated serum PAP. Both immunoassays were somewhat more effective clinically in measuring prostatic specific acid phosphatase than an enzyme colorimetric assay. The results obtained by CIE agreed with the results obtained by RIA in 96 per cent of the tests. The number of positive results in patients with confirmed prostate adenocarcinoma increased with disease progression. The low number of positive tests in localized adenocarcinoma (Stages A and B) suggests that neither the CIE nor any RIA procedure is useful for screening unselected populations for adenocarcinoma of the prostate.

The diagnosis and detection of urogenital cancers

Previously, histologic precision in the diagnosis of urologic cancers had, for some time, remained stable. More recently, variations in classifications of testis tumors, prostate cancer, and to some degree, bladder tumors, have been introduced. Most systems have in concurrence a desire or an attempt to infer better prognostic assessment in the overall results to treatment. With the advent of additional biological markers or direct enzymatic measurements, e.g., in prostate cancer, further improvements in identifying at risk populations, responses to treatment, and possible indications for variations in treatment, have ensued. These developments alone unquestionably mark the greatest area of change in the recent decade. The extent of disease assessment prior to definitive therapy, whether by arteriography, ultrasound, CAT scanning, or an occasional lymphangiography, has also influenced or modified treatment decisions. For continuing care and follow-up, several of these noninvasive techniques are now becoming included in the more standard approaches. Noninvasive techniques have been introduced for the therapy of renal tumors such as inducing infarction of the primary tumor. Endoscopic ultrasonic techniques have been particularly useful in assessing the size of pelvic tumors and response to treatment, even in detection of unexpected multiple primaries or metastatic extensions. Overall, the precision in urologic cancer, both for diagnostic and detection purposes, has been increased with these introductions.

Cancer serum index: a useful nonspecific test as a parameter in multimodality screening and assessment of patients with cancer of the prostate

A satisfactory, simple test for screening and monitoring of patients with prostatic cancer is still being sought. We suggest the use of a nonspecific test in combination with other tests. The ratio of two serum proteins (alpha 1 acid glycoprotein [AGP] and prealbumin [PAB]), may be useful markers for a cancer serum index (CSI). By separating serum components by gradient polyacrylamide gel electrophoresis, staining and quantitating these proteins by scanning densitometry, and dividing the area of AGP by that of PAB, indices can be obtained. In a test of sera from 450 patients with prostatic cancer, other urologic problems, and normal controls, CSIs of 360 sera presently decoded were found to be: (Formula: see text). The CSI should prove highly valuable when used in combination with selected prostatic cancer tests.

A solid-phase immunoadsorbent assay for serum prostatic acid phosphatase

A solid-phase immunoadsorbent assay for serum prostatic acid phosphatase (PAP) measurement has been developed as modified from our previously reported immunofluoroassay, utilizing the specific anti-PAP antibodies conjugated to CNBr-activated Sepharose 4B. The serum prostatic acid phosphatase was bound, and separated from other acid phosphatases and serum proteins, by the solid-phase anti-PAP IgG Sepharose 4B. The enzyme activity was quantitated by measuring the enzyme hydrolytic product, alpha-naphthol, from a primary standard solution. The entire procedure could be performed within four hours. The sensitivity of this method was 0.22 I.U./l of enzyme activity or 0.88 ng of prostatic acic phosphatase protein per ml of serum. Normal range of serum prostatic acid phosphatase as determined by this assay was found to be 0.4--2.4 I.U./l of enzyme activity (or 1.60--9.60 ng of enzyme protein per ml of serum). Initial clinical evaluation showed that 19 of 25 patients with early stages of prostatic cancer and 12 of 14 patients with metastatic prostatic cancer exhibited an elevated enzyme level (overall 79%), as compared with only six and eight patients, respectively (overall 36%), by a conventional chemical method.

Counterimmunoelectrophoretic studies of serum prostatic acid phosphatase

A counterimmunoelectrophoretic (CIEP) assay for the specific determination of prostatic acid phosphatase (PAP) is described. PAP was obtained from benign human prostatic tissue and a specific antiserum to this enzyme was produced in rabbits and goats. The lowest detectable activity of PAP was at 0.3 IU/l or 4 ng./0.1 ml. This CIEP method was compared to a standard biochemical method (Roy) on a wide spectrum of prostatic and nonprostatic disease. Nonprostatic malignancies and other disorders associated with hyperacidphosphatasemia by the biochemical method were found to be nonreactive for PAP by CIEP. Patients under treatment with various stages of prostatic carcinoma showed comparable elevations by both methods (35%). In untreated patients, the CIEP was statistically most sensitive in stage A (39% by CIEP and 14% by chemical).

Clinical significance of serum and bone marrow acid phosphatase

Currently available immunochemical assays for the determination of serum prostatic acid phosphatase have improved the reliability of this biological marker in carcinoma of the prostate. Although the value of such methods for screening the general population is questionable, a certain percentage of elevated serum levels is observed in patients with localized disease. The significance of such findings is unclear at the present time. Recent evidence suggests that in elevated bone marrow acid phosphatase, using these methods is of predictive value in the future development of metastatic disease.