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M C Wang

Publications and source records attributed to M C Wang.

At least 127 records · Page 7Linked to original sources
PubMed1981

Expression of prostatic acid phosphatase in human prostate cancer.

By a specific immunochemical measurement, the activity of prostatic acid phosphatase (PAP) in prostate cancer was found to be about 25%, on average, based on micrograms DNA or per cell, of that in normal prostate or benign prostatic hypertrophy (BPH). The reduction of PAP in prostate cancer was further revealed by a decrease in PAP protein. The 125I-labeled anti-PAP IgG specifically bound to nascent peptides on PAP-synthesizing polysomes showed no qualitative differences among cancerous prostate, normal prostate and BPH. However, the quantitative binding of 125I-labeled anti-PAP IgG to polysomes of cancerous prostate was half that of normal prostate of BPH. These data suggest that a significant amount of PAP and its synthesizing polysomes was reduced in prostate cancer as a result of PAP gene suppression.

Acid Phosphatase↗
PubMed1981

A simplified radioimmunoassay for plasma 11-deoxycortisol.

A simple, specific, accurate, precise and sensitive radioimmunoassay procedure developed for plasma 11-deoxycortisol is described. 1. The assay employs an anti-11-deoxycortisol serum generated against 11-deoxycortisol-3-(0-carboxymethyl) oxime coupled to bovine serum albumin, crystalline 11-deoxycortisol as standard, and [3H] 11-deoxycortisol as the radioactive ligand. 2. Cross-reactivity studies performed with structurally related steroids indicated cross reactivities with 17 alpha-hydroxyprogesterone, deoxycorticosterone and progesterone of 2.0%, 1.3% and 0.4% respectively; cortisone, corticosterone, cortisol, testosterone, less than 0.1%; and estrone, 17-beta-estradiol, estriol, and metyrapone less than 0.001%. Due to the high specificity of the anti-11-deoxycortisol serum, the method is simplified by the lack of need for chromatographic purification of the organic solvent extract of the plasma prior to the radioimmunoassay. The procedure was validated by comparing values for plasma 11-deoxycortisol with and without preliminary purification by chromatography on Sephadex LH-20 columns (y = 0.99 R/-x + 4.0, r = .98). Pretreatment of the plasma with n-hexane was found to eliminate interferences from high concentrations of 17 alpha-hydroxyprogesterone or progesterone. 3. Parallel dose-response curves were demonstrated between dilutions of plasma with elevated 11-deoxycortisol concentrations and the standard reference preparation. A non-specific binding less than 4% of the total [3H] 11-deoxycortisol was routinely observed. The detection limit of the assay was approximately 10 pg of 11-deoxycortisol which corresponds to a plasma concentration of approximately 0.7 micrograms/L 4. The analytical recovery of 11-deoxycortisol added to human plasma varied from 88 to 108%, with a mean recovery of 100%. The inter-assay variation was determined by assaying (n = 30) three different quality control pools. The following data were obtained: x 1 = 3.8 +/- 0.6 micrograms/L (CV = 15.8%); x 2 = 18.5 +/- 2.0 micrograms/L (CV = 10.8%); x 3 = 43.0 +/- 3.7 micrograms/dl (CV = 8.6%).

17-Hydroxycorticosteroids↗
PubMed1981

Prostate antigen: a marker for human prostate epithelial cells.

Specificity of a previously reported prostate antigen (PA) was assessed by several immunologic procedures. This antigen, restricted in distribution to the prostate gland, was detected within ductal epithelial cells. Continuous established cell lines LNCaP and PC-3 of malignant prostate origin retained the expression of PA. Tumor cells released the antigen in vitro into the culture fluid and also in vivo into the circulation of nude mice preinoculated with LNCaP cells. Prostate cells in culture also specifically accreted immunoglobulin fragments of PA antiserum.

Animals↗
PubMed1981

Use of human prostate-specific antigen in monitoring prostate cancer.

The newly reported human prostate-specific antigen (PA) is a specific histiotypic product of human prostate. With the use of a sensitive enzyme immunoassay, the circulating PA in prostatic cancer patients has been evaluated clinically. In 96 patients with advanced stage of disease (D2) and receiving chemotherapies, the pretreatment serum PA levels were found to be of prognostic value with regard to the patient survival. Ten patients with metastatic prostate cancer were monitored for more than 32 weeks by 183 serial PA values and were found generally to respond to the treatment. Additionally, in another group of 32 patients who underwent curative therapies for localized prostate cancer, 161 serum samples were evaluated during periods of 12 to 114 weeks (average 56 weeks). Of these patients, five developed metastases during follow-up, and all were shown to exhibit increasingly elevated PA values, either corresponding to or preceding the clinical diagnosis of disease recurrence. These results suggest that PA is a new marker with potential value to merit further clinical study.

Antigens, Neoplasm↗
PubMed1980

Fundamental biochemical and immunological aspects of prostatic acid phosphatase.

Prostatic acid phosphatase (PAP) was purified from human malignant prostate tissue by means of ammonium sulfate fractionation followed by sequential chromatographies of ion exchange, affinity column, and gel filtration. PAP has a molecular weight of 100,000 and consists of two subunits of 50,000. Owing, in part, to sialic acid contents in the molecule, PAP has multiple isoelectric points (pIs) at 4.2-5.5. In 0.2 M citrate, PAP has the highest affinity (Km 9.2 x 10(-5) M) in hydrolyzing alpha-naphthyl phosphate among the phosphomonoesters. Tartrate and heat at 37 degrees C for 2 hours almost completely inhibit PAP enzymic activity. By immunoprecipitate technique, anti-PAP heteroantiserum exhibited a distinct immunologic characteristics. Further, PAP possessed different antibody-binding site from enzyme hydrolytic site.

Acid Phosphatase↗
PubMed1980

Development and validation of a choriogonadotropin beta-subunit radioimmunoassay for serum choriogonadotropin using commercially available components.

A sensitive, specific, accurate and precise radioimmunoassay procedure developed for the beta-subunit of serum choriogonadotropin (hCGbeta) is described. 1. The assay employs an anti-hCGbeta (rabbit) serum generated against hCGbeta, highly purified intact choriogonadotropin (hCG) as standard, and [125I]hCG as the radioactive ligand. The antibody-bound hCG was separated from the free hormone by the addition of goat anti-rabbit gamma-globulin. 2. The detection limit of the assay was approximately 75 microIU hCG which corresponds to a serum concentration of approximately 0.75 mIU/mL. 3. Cross reactivity studies performed with human luteinizing hormone (hLH) and human thyroid-stimulating hormone (hTSH) indicated minimal interferences from these structurally similar glycoproteins. Parallel dose-response curves were demonstrated between dilutions of sera with elevated hCG concentrations and the standard reference preparation. A non-specific binding of less than 2.5% of the total [125I]hCG was routinely observed. 4. The analytical recovery of hCG added to human sera varied from 94 to 110%, with a mean recovery of 101%. 5. The inter-assay variation was determined by assaying (n=30) 3 different quality control pools. The following data were obtained: X1=4.6 +/- 0.5 mIU/mL (CV=10.9%); X2=8.1 +/- 0.9 mIU/mL (CV=11.1%); and X3=36.8 +/- 2.8 mIU/mL (CV=7.6%). 6. The clinical data collected from subjects with trophoblastic disease agreed with previously published studies. All of the reagents are available commercially.

Chorionic Gonadotropin↗
PubMed1980

Quantitation of prostate-specific antigen in serum by a sensitive enzyme immunoassay.

A sensitive sandwich-type enzyme immunoassay has been developed for quantitation of a human prostate-specific antigen (PA). With this method, PA at a concentration as low as 0.10 ng/ml can be detected. The assay was reproducible as within and between assays yielded a coefficient of variation of 5.7% and 4.6%, respectively. Only human prostate tissues (n = 31) were shown to contain PA. No PA was detected in other human normal or tumor tissues (n = 13). PA was not detectable in sera from normal females (n = 17) or female cancer patients (n = 25). A mean +/- S.D. of 0.47 +/- 0.661 ng/ml (ranging from less than 0.10 to 2.6) ws obtained from a group of 51 normal males. Sera from male patients with nonprostatic cancer contained a similar range of PA as that of normal males. Patients with prostate cancer (371 of 442) and benign prostatic hypertrophy (13 of 19) were shown to have elevated levels of circulating PA. Although no quantitative difference in PA levels was found between the benign prostatic hypertrophy group and Stage A of prostatic cancer, patients with Stages C and D prostatic cancer exhibited significantly elevated levels of PA qualitatively and quantitatively. These results therefore indicate that PA is a histiotypic product of the prostate and may be of use as an adjunctive tool in diagnostic procedures of prostate cancer.

Antigens↗
PubMed1980

A prostate antigen in sera of prostatic cancer patients.

A prostate antigen has been detected by a rocket immunoelectrophoresis technique in 17 of 219 sera obtained from patients with advanced prostatic cancer. Sera from 175 patients with nonprostatic cancers, including those with late-stage disease of the breast, lung, colon, rectum, stomach, and pancreas, were antigen negative as were 20 samples each from normal adults and age-matched males. Antigen in sera showed immunological identity with antigen in prostate tissue as determined by immunoprecipitation peak enhancement experiments. Using antibody affinity chromatography and radioimmunoprecipitation techniques, the antigen in sera was purified and subjected to sodium dodecyl sulfate electrophoresis; it exhibited a molecular weight of approximately 36,000, similar to that of antigen isolated from prostatic tissue.

Acid Phosphatase↗
PubMed1980

Quantitative counterimmunoelectrophoresis assay for prostatic acid phosphatase.

We developed two quantitative counterimmunoelectrophoretic (CIEP) assays to detect serum prostatic acid phosphatase (PAP). The assays were designated counterimmunoelectrophoresis-colorimetric (CIE-C) and counterimmunoelectrophoresis-densitometric (CIE-D). One unique feature of these assays was the use of a primary standard for the quantitation of PAP. The sensitivities of the assays were 0.08 and 0.04 IU per liter for CIE-C and CIE-D, respectively. Precision coefficients of variation and recovery studies for four levels of PAP over a 3-month period have shown the reliability of these newly modified assays. PAP activity in sera from patients with early stages of prostatic cancer which was demonstrated to be normal by conventional chemical methods was found to be elevated by the conbined methods in a substantial number.

Acid Phosphatase↗
PubMed1979

Evaluation of serum digoxin and serum cortisol by radioimmunoassay with the Concept-4.

The solid-phase radioimmunoassay procedures for serum digoxin and cortisol with the Concept-4 were evaluated for specificity, correlation with other radioimmunoassay procedures, parallelism, recovery, carryover, and precision. 1. The detection limits of the digoxin and cortisol assays were 10 pg/tube and 40 pg/tube, respectively. These detections correspond to serum concentrations of 0.25 micrograms/liter and 20 micrograms/liter, respectively, for digoxin and cortisol. 2. Specificity of the digoxin assay was characterized by a 18.3% cross reaction with digitoxin. The anti-cortisol with 11-deoxycortisol, cross reaction with 11-deoxycortisol. 3. The values obtained with the Concept-4 for both procedures demonstrated acceptable correlations with other existing RIA procedures. 4. Dilution studies conducted to determine the parallelism of the 2 assays indicated that both assays demonstrated excellent proportionality between the volume of specimen and the quantity of analyte measured. 5. Analytical recoveries of digoxin and cortisol added to the individual assays average 95% and 101%, respectively. 6. Carryover studies indicated a routine sample-to-sample interaction of less than 0.05% for both assays. 7. The digoxin assay routinely demonstrated intra- and inter-assay variations of less than 7.4% and less than 10.0%, respectively. The precision data for cortisol indicated intra- and inter-assay variations of less than 6.7% and less than 9.1%, respectively.

Chemistry, Clinical↗
PubMed1979

Non-chromatographic radioimmunoassay procedure for urinary aldosterone.

We describe a sensitive, specific, and simple procedure for measuring aldosterone in human urine, which requires no chromatographic purification before quantification by radioimmunoassay but does include hydrolysis and extraction steps. Rabbit anti-aldosterone serum is sued, generated against aldosterone-18,21-dihemisuccinate coupled to human serum albumin. The antibody cross reacted little with other structurally related steroids that are in human urine. Our procedure was validated by comparing values for urinary aldosterone in human urine, with and without preliminary purification by chromatography on either paper (y = 0.92x + 2.9; r = 0.99; p less than 0.01) or (Sephadex LH-20) column (y = 0.98x + 0.6; r = 0.99; p less than 0.01). Values by our procedure also correlated well (y = 1.03x - 0.8; r = 0.99; p less than 0.01) with those obtained with use of a validated commercial "kit" for urinary aldosterine. All reagents for the proposed method are available commercially.

Adult↗
PubMed1979

Purification of a human prostate specific antigen.

Rabbit antiserum raised against the crude extract of normal human prostatic tissue contained antibodies to a prostatic tissue-specific antigen as shown by immunoprecipitation techniques. Using this antiserum a prostate antigen was detected in normal, benign hypertrophic, and malignant prostatic tissues, but not in other human tissues. The prostate antigen was purified to homogeneity from prostatic tissues and showed a single protein band on analytical polyacrylamide gel electrophoresis and isoelectric focusing. This report thus presents the first demonstration of the purification of a prostate-specific antigen that does not represent prostatic acid phosphatase.

Antigens↗
PubMed1978

Isoenzymes of human prostate acid phosphatase.

The isoenzymes of human prostatic acid phosphatase have been studied by an isoelectric focusing technique. Purified acid phosphatase from malignant prostates contained eight isoenzymes with pI 4.4--5.3. The sera from patients with prostate cancer were shown to have similar acid phosphatase isoenzyme patterns at pI 4.0--5.5; as the serum enzyme activities increased, the pI of isoenzymes shifted to more acidic pH. These isoenzyme patterns of sera from patients with prostate cancer were different from those of patients with Gaucher's disease or from acid phosphatase of human erythrocytes, both of which exhibited only one enzyme band around pI 5.0 and 6.0, respectively. Treatment of serum sample of prostate cancer with neuraminidase did not result in a single enzyme band but alter the pI of isoenzymes, which shifted to a higher pH region. The significance of acid phosphatase activities and its isoenzyme patterns in prostate cancer merits further investigation.

Acid Phosphatase↗