PubMed Health⌕ Search

Biomedical subjects

D W Mercer

Publications and source records attributed to D W Mercer.

At least 55 records · Page 3Linked to original sources
PubMed1986

Microcomputer-assisted interpretative reporting of sequential cardiac profile data.

The authors have developed a microcomputer-based system for interpretative reporting of sequential cardiac profile data, which consists of creatine kinase and lactate dehydrogenase isoenzyme levels. Patient demographic data and test results (total creatine kinase [CK], MB isoenzyme of CK [CK-MB], lactate dehydrogenase isoenzyme 1 [LD-1], and lactate dehydrogenase isoenzyme 2 [LD-2]) are entered manually through the keyboard. Percent MB and LD ratio are calculated. The test results are compared with normal range values, and an interpretative report is generated, including all pertinent demographic information and graphic display of up to 36 previous CK and LD isoenzyme determinations. Interpretative statements are printed beneath the graphic display after analysis of previous test results. The combination of graphic data display and interpretations based on prior data provides useful and accurate information to the cardiologist. Significant discrepancies between computer-assisted and pathologist interpretation were not encountered.

Clinical Enzyme Tests↗
PubMed1985

Multiple markers of malignancy in sera of patients with colorectal carcinoma: preliminary clinical studies.

Eleven potential biochemical markers were measured in serum from 33 patients with malignant and 13 with benign colorectal disease: four isoenzymes (creatine kinase-BB, homoarginine-sensitive alkaline phosphatase, salivary-type amylase, and macro-creatine kinase type 2), five specific proteins (ferritin, alpha 1-acid glycoprotein, C-reactive protein, alpha 1-antitrypsin, and ceruloplasmin), one oncofetal antigen (carcinoembryonic antigen, CEA), and one hormone (beta human choriogonadotropin). The sensitivity of individual markers for the detection of early-stage malignancy (n = 11) ranged from 0% to 64% (CEA 18%); for late-stage colon malignancy (n = 12) from 8% to 83% (CEA 83%). Specificity in patients (n = 10) with benign intestinal disease ranged from 80% to 100% (CEA 100%). The five most-sensitive markers--C-reactive protein, alpha 1-glycoprotein, CEA, macrocreatine kinase type 2, and homoarginine-sensitive alkaline phosphatase--were selected for use as a "colon panel." In retrospective comparison, use of the colon panel instead of CEA alone increased sensitivity by 17% and 64% for late-and early-stage cancer, respectively; specificity, however, decreased by 30%, but should improve with serial testing.

Adult↗
PubMed1978

Multiple forms of acid phosphatase activity in Gaucher's disease.

Although the primary genetic defect in all individuals with Gaucher's disease is a deficiency in glucocerebrosidase activity, the finding of marked elevations in splenic and serum acid phosphatase activity is almost as consistent a finding. Gaucher spleen and serum contain at least two forms of acid phosphatase that can be readily separated by chromatography on columns containing the cation exchange resin Sulphopropyl Sephadex. The major species of acid phosphatase (designated SP-I) contained in Triton X-100 (1% v/v) extracts of Gaucher spleen accounts for 65%--95% of the total activity and has the following properties: (1) it does not bind to the cation exchange column; (2) it exhibitis a pH optimum of 4.5--5.0; (3) it is inhibited by sodium fluoride (15 mM), L(+)-tartaric acid (20 mM), and beta-mercaptoethanol (2.1 M), and (4) it is resistant to inhibition by sodium dithionite (10 mM). The minor acid phosphatase activity (designated SP-II) present in extracts of Gaucher spleen has properties similar to those of the major species of acid phosphatase activity contained in serum from patients with Gaucher's disease: (1) it binds firmly to cation exchange columns (eluted by 0.5 M sodium chloride); (2) it exhibits a pH optimum of 5.0--6.0; (3) it is inhibited by sodium fluoride and sodium dithionite; and (4) it is resistant to inhibition by beta-mercaptoethanol (2.1 M) and L(+)-tartaric acid (20 mM). In addition, a second form of acid phosphatase that is tartrate resistant was found to be elevated in Gaucher serum. This form of serum acid phosphatase did not bind to Sulphopropyl Sephadex, was found to be significantly resistant to beta-mercaptoethanol (2.1 M), and was only partially inhibited by sodium dithionite (10 mM). The findings reported here indicate that at least three distinct forms of acid phosphatase activity are elevated in Gaucher's disease. Furthermore, the minor acid phosphatase activity contained in spleen homogenates has properties very similar to those of the major acid phosphatase activity observed to be present in serum of patients with Gaucher's disease. These data indicate that simple spleen spillage cannot account for the increased levels of serum acid phosphatase in patients with Gaucher's disease.

Acid Phosphatase↗
PubMed1978

Lactic dehydrogenase isoenzyme determination in the diagnosis of acute myocardial infarction.

Lactic dehydrogenase (LD) isoenzymes were determined by a rapid, simple technique and their utility in the diagnosis of acute myocardial infarction (AMI) was evaluated. LD isoenzymes were separated by ion-exchange column chromatography using DEAE-Sephadex. The cardiac fractions (LD-1 and LD-2) were measured separately on an Abbott ABA-100 analyzer and ratio of LD isoenzyme 1 to LD isoenzyme 2 (LD1:2) calculated. Daily serum samples were obtained from 100 patients selected only for a history of chest pain of abrupt onset. In 47 patients whose diagnosis was acute myocardial infarction (AMI), confirmed by typical clinical presentation and typical rise in cardiac-specific creatine kinase isoenzyme (MB(, peak LD1:2 ranged from 0.77 to 2.26. In 44 patients without AMI, peak LD1:2 ranged from 0.25 to 0.76. In two patients with electrocardiographic changes chest pain occurred two and five days previously; there was no rise in MB, but LD1:2 was elevated. Four patients with small AMI had no rise in LD1:2. Three more patients (one with active hemolysis) had false positive results. Thus, there was a sensitivity of 96% and a specificity of 97% when the cut-off point was LD1:2 = 0.76. LD1:2 is not quite as sensitive or specific as MD, but the ratio allows for the diagnosis of infarction in cases where MB has already returned to normal.

Acute Disease↗
PubMed1978

Improved column method for separating lactate dehydrogenase isoenzymes 1 and 2.

Lactate dehydrogenase (LD) isoenzymes 1 and 2 in human serum were separated on a column of diethylaminoethyl-Sephadex. Samples layered on mini-columns were eluted with buffered sodium chloride (100, 150, and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was evaluated by electrophoresis on polyacrylamide gel. Results for column-fractionated LD-1 and LD-2 were expressed in two ways: LD-1/LD-2 ratios and total LD-1 + LD-2 activities. The former is a more specific indicator of myocardial infarction than the latter. Sera from 10 patients with acute myocardial infarction (increased creatine kinease isoenzyme MB activity) exhibited ratios in the range of 0.92 to 1.56, ratios for 10 patients without heart disease (normal creatine kinase MB) ranged from 0.33 to 0.69.

Chromatography, Ion Exchange↗
PubMed1977

Acid phosphatase isoenzymes in Gaucher's disease.

Acid phosphatase (EC 3.1.3.2) isoenzyme profiles of extracts of splenic tissue and serum from patients with Gaucher's disease were measured by a mini-column ion-exchange chromatographic method [Clin. Chem., 23, 000 (1977)]. Diagnosis of Gaucher's disease in the five patients studied was confirmed by demonstrating decreased (2.3 to 4.1% of normal) glucocerebrosidase activity in the spleen. With p-nitrophenyl phosphate as substrate, increased acid phosphatase activity (three-to eight-fold normal) was demonstrated in spleen tissue from Gaucher;s disease patients; isoenzyme profiles by the ion-exchange column technique showed acid phosphatase isoenzyme 5 to be the predominant isoenzyme. Comparison of acid phosphatase isoenzyme profiles from patients with Gaucher's disease and prostatic carcinoma revealed distinct differences in the activities of isoenzymes 2 and 5. The isoenzyme-5 measurement thus appears to provide a diagnostic test for Gaucher's disease that can be done reapidly and easily in the routine clinical chemistry laboratory.

Acid Phosphatase↗
PubMed1977

Separation of tissue and serum acid phosphatase isoenzymes by ion-exchange column chromatography.

I describe a simple, rapid ion-exchange column-chromatographic technique for separating the acid phosphatase (EC 3.1.3.2) isoenzymes in human serum and tissue. Extracts of platelets, spleen, liver, erythrocytes, and prostate were used to determine optimum conditions for separating these isoenzymes. Samples layered on mini-colunms of DEAE-Sephadex A-50 were eluted stepwise with sodium chloride (100, 200, and 300 mmol/liter, buffered with tris (hydroxymethyl)aminomethane). Activity in column effluents was measured with p-nitrophenol phosphate as substrate, and their isoenzyme content was assessed by electrophoresis on polyacrylamide gel. Comparision of activity patterns so derived for various tissues revealed prostatic tissue to be a rich source of acid phosphatase isoenzyme 2 activity. Evaluation of sera from six patients with prostatic cancer revealed isoenzyme patterns with prominent amount of isoenzyme 2 (3.8 to 27.6 U/liter). sera from 10 healthy laboratory technicians contained isoenzyme 2 in the range of 0.3-0.5 U/liter. Samples from two patients with abnormally high activity owing to nonprostatic conditions (Gaucher's disease and carcinoma of lung) exhibited less than 2 U of isoenzyme 2 per liter and acid phosphatase isoenzymes 3-5 that were 50- to 100-fold the normal range. Quantification of isoenzyme 2 by DEAE-Sephadex column chromatography as described appears to provide a more sensitive and specific approach to diagnosis of prostatic cancer.

Acid Phosphatase↗
PubMed1975

Cardiac specific creatine phosphokinase isoenzyme in the diagnosis of acute myocardial infarction.

The specific and sensitivity of serum creatine phosphokinase cardiac specific isoenzyme (MB) in the diagnosis of acute myocardial infarction (AMI) was evaluated. An ion-exchange chromatographic technique was used to isolate MB. Sera layered on mini-columns of DEAE-Sephadex were eluted with Tris-buffered sodium chloride. Quantification of isolated MB was performed by creatine phosphokinase (CPK) assay (Rosalki method) of column effluents. MB was expressed as a percentage of the simultaneously determined total serum CPK; MB was determined in 100 consecutive admissions to the Coronary Care Unit. Acute myocardial infarction was diagnosed by accepted criteria. In 47 patients with proven AMI, including three with normal total CPK, peak MB was greater than 4% of total CPK. In 49 patients without AMI, including 15 with elevated total CPK (due to trauma, injections, cardioversion), peak MB was less than 2% of total CPK. MB was elevated, but did not peak in four patients without AMI but with chronic atrial fibrillation. Isolation and quantification of MB by this technique is rapidly and easily performed and provides a specific and extremely sensitive tool for the diagnosis of AMI.

Atrial Fibrillation↗
PubMed1975

Detection of cardiac-specific creatine kinase isoenzyme in sera with normal or slightly increased total creatine kinase activity.

We describe a spectrophotometric kinetic assay for detecting creatine kinase MB isoenzyme activity in the 1 to 10 U/liter range. The MB isoenzyme was isolated [Clin. Chem. 20, 36 (1974)] and assayed (Rosalki method) with an Abbott ABA-100. Good reproducibility was demonstrated for MB isoenzyme activities near 1 U/liter (CV = 2.6%). Sera with normal or slightly increased total creatine kinase activity were evaluated. Sera of 14 patients with acute myocardial infarction contained, per liter, 84 to 236 U of total creatine kinase activity and 4.6 to 28.0 U of isoenzyme MB activity; corresponding ranges for sera from healthy lab technicians and patients with noncardiac disease were 36 to 277 and 0 to 2.6 U. MB isoenzyme activity for infarction patients rose and fell sharply within three days after the infarction. Atypical time-course patterns, MB isoenzyme activity remaining abnormally great for five days, were observed in serum from patients with prolonged atrial fibrillation and congestive heart failure or cardiomyopathy; the BB isoenzyme (1 to 5 U/liter) was also detected in sera of such patients but was absent in sera from infarcation patients. Quantification of column-isolated MB by the assay described is rapid, easy, specific, and extremely sensitive for measuring MB in the 1 to 10 U/liter range.

Chromatography, DEAE-Cellulose↗
PubMed1975

Simultaneous separation of serum creatine kinase and lactate dehydrogenase isoenzymes by ion-exchange column chromatography.

Lactate dehydrogenase isoenzymes were partially separated by use of a previously described column technique for creatine kinase [Clin. Chem. 20, 36 (1974)]. Extracts of lactate dehydrogenase-rich tissues were used to evaluate column resolution. Samples layered on mini-columns containing DEAE-Sephadex were eluted with Tris-buffered sodium chloride (100 and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was assessed by electrophoresis on polyacrylamide gel. Dehydrogenase isoenzymes 3, 4, and 5 were separated from isoenzymes 1 and 2, and the separation was tissue-specific and reproducible. The electrophoretic technique for isoenzymes 3, 4, and 5 gave values about 20% lower than did the column technique. Sera from 15 healthy laboratory technicians contained total lactate dehydrogenase, isoenzymes 1 and 2, and isoenzymes 3, 4, and 5 in the ranges 94 to 152, 34 to 64, and 38 to 75 U/liter, respectively. Activities of sera from 15 patients with acute myocardial infarction (total lactate dehydrogenase) ranged from 212 to 800 U/liter and lactate dehydrogenase isoenzymes 1 and 2 ranged from 138 to 628 U/liter. Lactate dehydrogenase and creatine kinase isoenzymes were rapidly and easily measured after being simultaneously separated. The procedure is specific and sensitive for following the post-infarct time course of changes in isoenzyme activities.

Chromatography, DEAE-Cellulose↗
PubMed1973

Protein digestion in human intestine as reflected in luminal, mucosal, and plasma amino acid concentrations after meals.

Normal human volunteers were intubated with either aspiration tubes or a biopsy capsule placed in the small intestine. The subjects were then fed a test meal containing 50 g of purified bovine serum albumin which served as the model dietary protein. Electrophoretic analysis of intestinal fluids showed that for at least 4 h the fed albumin was detectable in jejunal and ileal fluids. On separate occasions, subjects were fed the same meal without the protein. No protein was detected in intestinal fluids when the protein-free meal was fed. After the protein-rich meal, total concentrations of measured free and peptide amino acids rose from 3.21 to 29.29, and 15.94 to 117.97 mumol/ml, respectively, (P values < 0.02) in the jejunum. Similarly, total concentrations of measured free and peptide amino acids rose from 5.45 to 19.74, and 13.59 to 65.39, respectively, (P values < 0.05) in the ileum. In contrast, concentrations of free and peptide amino acids in intestinal fluids did not increase after the protein-free meal. While intracellular concentrations of amino acids in the jejunal mucosa did not show significant changes, plasma concentrations of each individual free amino acid were increased after the protein-rich meal and were either decreased or unaltered after the protein-free meal. The amino acid composition of the fed protein was reflected in the increases in intraluminal and plasma concentrations of individual amino acids after the protein-rich meal. It is concluded that after the ingestion of a test meal containing a substantial amount of protein which is within the usual range of dietary intake; (a) the exogenous protein is the principal source of the increased free and peptide amino acids in the intraluminal contents and in the plasma; (b) there are greater amounts of amino acids present as small peptides than in the free form in the gut lumen; (c) the ingested protein can be recovered as late as 4 h both in the jejunum and in the ileum.

Adult↗