Reference intervals for prostate-specific antigen.
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Biomedical subjects
Publications and source records attributed to B Seamonds.
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Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) have been evaluated in patients with prostate cancer, benign prostatic hypertrophy (BPH), and prostatitis. PSA has proved to be diagnostically more sensitive than PAP for the detection of prostate cancer: 95.0 per cent vs 60.0 per cent for 40 newly diagnosed cancer cases, and 97.1 per cent vs 65.7 per cent for 35 relapsed cases. This also holds true for those patients with early-stage disease: 71.4 per cent vs 0 per cent for 7 Stage A1 cases. The specificities of PSA and PAP are comparable, 96.8 per cent vs 98.9 per cent, respectively. PSA is also more sensitive for monitoring therapy, since it usually rises before PAP and always precedes clinical signs of relapse. Although PSA may be elevated more frequently than PAP in some patients with BPH and prostatitis, it is postulated that these patients with elevated serum PSA and normal serum PAP may fall into a high-risk sub-population which may have early prostate cancer or precancerous conditions not easily detectable by current clinical and diagnostic techniques. Our data suggest PSA is a sensitive useful tumor marker for the diagnosis and management of prostate cancer. In addition, PAP, in combination with PSA, may serve as a useful adjunct for differential diagnosis and confirmation of advanced stage prostate cancer.
The effect of the gastric alkaline tide on serum-ionized calcium levels was determined in human subjects. Gastric acid seretion was stimulated by a standard steak meal, human synthetic gastrin, and betazole hydrochloride. Ionized calcium levels fell to a similar extent after each stimulus. The mean decrease in calcium ion concentration in all experiments was 5.4% of the basal concentration. The fall in serum calcium ion concentration was highly correlated with the rise in serum pH. We speculate that increased formation of calcium bicarbonate complex in the serum as well as increased binding of ionized calcium by serum protein accounts for the surprisingly large effect of the alkaline tide on serumionized calcium levels.
Oxygen and carbon monoxide kinetics of Glycera dibranchiata monomeric hemoglobin have been studied using laser photolysis, air flash, and stopped flow techniques. The reactions of this hemoglobin with both ligands were found to be more rapid than the corresponding reactions involving myoglobin and were also biphasic in nature, the rate constants being approximately an order of magnitude different for the fast and slow phases in each case. No pH or hemoglobin concentration dependence of the pseudo-first order rate constants was apparent between pH 6 and 9 and in the concentration range of 1.25 to 40 muM heme. Both fast and slow pseudo-first order oxygen combination rate constants varied linearly with oxygen concentration between 16 and 1300 muM. A first order slow relaxation was also noted which was linearly dependent on heme concentration and inversely dependent on oxygen concentration. This reaction has been shown to be due to a replacement of oxygen by carbon monoxide. The presence of this reaction is a result of the high affinity of Glycera monomer for carbon monoxide as shown by the partition coefficient Mr = approximately 20,000 ana an equilibrium dissociation constant of the order L = 1.1 X 10(-9) M.