bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentrations of lipids and apolipoproteins in patients with clinically well-controlled insulin-dependent and non-insulin-dependent diabetes.
Authors: Joven J , Vilella E , Costa B , Turner P R , Richart C , Masana L 
Published: January 2020

Abstract
The triglyceride and cholesterol content of total, very-low-, intermediate-, low-, and high-density lipoproteins, and of apolipoproteins (apo) Al, All, B, Cll, Clll, and E were determined in plasma from 107 patients with clinically well-controlled diabetes and from 66 age- and weight-matched healthy normal subjects. The diabetic patients were separated into two groups: those with insulin-dependent diabetes mellitus (IDDM, type 1, n = 24) and those with non-insulin-dependent diabetes mellitus (NIDDM, type 2, n = 83). The latter group contained two subgroups: those treated by diet (type 2d, n = 42) or by insulin (type 2i, n = 41). High-density lipoprotein cholesterol was increased in IDDM patients, and decreased in NIDDM patients relative to control subjects. Mean apo Al values in IDDM patients were higher than in their respective controls and in NIDDM patients. Concentrations of apo B, Clll, and E were higher in all diabetic patients than in the healthy controls, but those of apo Cll did not differ statistically between diabetics and nondiabetics. Although total plasma cholesterol and triglyceride concentrations were apparently near normal values in patients with good glycemic control, we found a persistent increase of intermediate-density lipoproteins (remnants) in all the diabetic groups studied. This factor may be related to the perceived increased cardiovascular risk in these individuals.
A simplified strategy for testing thyroid function.
Authors: Beaman J M , Woodhead J S 
Published: January 2020

Abstract
We assessed a new strategy for thyroid-function testing that involves simultaneous measurement of free thyroxin and thyrotropin, both in singletons, with chemiluminescent assays. Using our current strategy of measuring free thyroxin as a first-line test with selected back-up testing, the results show that, of 810 patients without previous thyroid disease, 445 received back-up tests. Of these, 345 were euthyroid, whereas 63 classified as euthyroid and not selected for further testing in fact had abnormal back-up test results. Evidently the simultaneous measurement of free thyroxin and thyrotropin with the "Magic Lite" technology greatly improves diagnostic efficiency compared with this current strategy.
Concentrations of some trace elements (Se, Zn, Cu, Fe, Mg, K) in blood and heart tissue of patients with coronary heart disease.
Authors: Oster O , Dahm M , Oelert H , Prellwitz W 
Published: January 2020

Abstract
We measured Se, Zn, Fe, Cu, Mg, and K in blood and heart tissue of patients with coronary heart disease. Such patients have subnormal selenium concentrations in serum, whole blood, and (calculated per gram of hemoglobin) erythrocytes. Concentrations of zinc and copper in serum were also subnormal in these patients. Heart tissue collected from these patients during bypass surgery was analyzed for Se, Zn, Fe, Cu, Mg, and K; results are expressed in terms of wet weight and in relation to nitrogen and phosphorus content. Concentrations of these elements in blood are correlated with those in heart tissue. Selenium concentrations in serum correlated positively with those in tissue but not with those in erythrocytes. We found no association between concentrations of zinc, iron, copper, magnesium, and potassium in serum and the corresponding concentrations in heart tissue. There was a moderately positive correlation between the concentration of ferritin in serum and that of iron in tissue. We conclude that the turnover rate for selenium in tissue is similar to that in serum but greater than that for erythrocyte selenium. The concentrations of these six elements in heart tissue are partly correlated with the ejection fraction of the left ventricle.
Proficiency testing on drugs of abuse: one year's experience in Spain.
Authors: Segura J , de la Torre R , Congost M , Camí J 
Published: January 2020

Abstract
The need for external quality control for drugs-of-abuse urinalysis has long been recognized. Based on experiences in other countries, a proficiency testing program has been introduced recently in Spain. Sterile urine samples containing different concentrations of drugs and metabolites are analyzed by participating laboratories four times a year. Comprehensive educational reports reviewed by an advisory committee are released after each batch analysis. The first year's results verify (a) a beneficial influence of the program in regard to reducing errors when adequate techniques are used, (b) the need for using confirmatory techniques, and (c) the importance of experience and laboratory resources for optimizing results. The educational aspects of the program for the second year are stressing especially the in situ training of analysts and the supply of solutions of drugs and metabolites to be used as reference standards.
Simplified method for screening populations at risk for transthyretin Met30-associated familial amyloidotic polyneuropathy.
Authors: Saraiva M J , Alves I L , Costa P P 
Published: January 2020

Abstract
This simple, reliable method for detecting the transthyretin-methionine30 [TTR(Met30)] mutation, found in patients with familial amyloidotic polyneuropathy (FAP), is based on production of an extra peptide fragment when the mutant TTR is treated with cyanogen bromide (CNBr). After electrophoresis of whole serum and excision of the TTR (prealbumin) band, the TTR-containing gel is incubated with CNBr, subjected to sodium dodecyl sulfate/polyacrylamide gel electrophoresis, and stained with silver to determine whether an abnormal CNBr fragment (residues 31-127) is present. Results can be obtained within two days. Several samples can be processed simultaneously, and no unusual equipment or reagents are required. The procedure is suitable for routine diagnosis of FAP and for epidemiological studies.
Exposure to environmental tobacco smoke measured by cotinine 125I-radioimmunoassay.
Authors: Knight G J , Palomaki G E , Lea D H , Haddow J E 
Published: January 2020

Abstract
We describe a polyclonal-antiserum-based 125I-radioimmunoassay for cotinine that is suitable for measuring nonsmokers' passive exposure to tobacco smoke in the environment. The standard curve ranged from 0.25 to 12.0 micrograms/L, with an estimated lower limit of sensitivity of 0.2 microgram/L (95% B/Bo = 0.2 microgram/L; 50% B/Bo = 4.0 micrograms/L). The median within-assay CVs for patients' samples with cotinine values from 0.4 to 1.3, 1.4 to 2.4, 2.5 to 4.6, and 4.7 to 15.6 micrograms/L were 13.9%, 7.2%, 5.1%, and 5.7%, respectively. Between-assay CVs for two quality-control sera with average values of 1.53 and 3.68 micrograms/L were 14.3% and 7.8%, respectively. Analytical recoveries of cotinine from smokers' sera diluted in zero calibrant ranged from 91% to 116%. Cotinine values determined on 79 paired sera and urines from nonsmokers showed significant correlation with self-reported exposure to environmental tobacco smoke (r = 0.49, P less than 0.001 for sera; r = 0.57, P less than 0.001 for urine). The log of the values for serum and urine cotinine were also significantly correlated (r = 0.85, P less than 0.001). Evidently, polyclonal antiserum can be used to develop a cotinine assay for measuring exposure to environmental tobacco smoke that compares well with that described for monoclonal-based assays.
Thin-layer chromatography of free porphyrins for diagnosis of porphyria.
Authors: Henderson M J 
Published: January 2020

Abstract
In this simple thin-layer chromatographic (TLC) technique for evaluating porphyrin excretion, porphyrins are extracted from urine or feces, then separated on silica-gel TLC plates. The distinct porphyrin bands are observed by viewing the plates under long-wave fluorescent light. Positive screening tests can readily be confirmed or rejected, and a more comprehensive investigation confidently undertaken.
Effects of therapeutic coronary reperfusion on aspartate aminotransferase isoenzymes in sera of patients with acute myocardial infarction.
Authors: Panteghini M , Pagani F , Cuccia C 
Published: January 2020

Abstract
We examined the kinetics of the catalytic activities of aspartate aminotransferase (AST, EC 2.6.1.1) isoenzymes in serum of 28 patients with myocardial infarction who were to receive either intracoronary urokinase--reperfusion angiographically proved--or conventional therapy (control group). Cytosolic (soluble) AST (s-AST) activity in serum increased rapidly immediately after recanalization, reaching a maximum 12 h after the onset of infarction. In the control group, this peak was reached 28 h after the onset (P less than 0.001). Peak s-AST activity was similar in the two groups. Peak activity and peak time for mitochondrial AST (m-AST) were the same for the two groups of patients; intervention that affects myocardial perfusion caused only a slight additional increase in m-AST activity in the early post-infarct period. There may be advantages to measuring m-AST, which is briefly influenced by reperfusion, instead of the usual cytosolic enzymes for assessment of myocardial damage in patients with myocardial infarction treated with thrombolytic therapy.
Correlation of HbA1C, glycated serum proteins and albumin, and fructosamine with the 24-h glucose profile of insulin-dependent pregnant diabetics.
Authors: Suhonen L , Stenman U H , Koivisto V , Teramo K 
Published: January 2020

Abstract
To assess the value of various methods for long-term follow-up of diabetic patients, we compared the concentrations of fructosamine in serum with those of various glycated proteins: hemoglobin (HbA1C), total serum proteins (G-prot), and albumin (G-alb), assayed in 30 pregnant insulin-dependent diabetics every two weeks after initial determination of a 24-h blood glucose profile. HbA1C correlated best with the 24-h glucose profile during the succeeding 10-35 days (r = 0.65-0.68, P less than 0.001). G-prot and G-alb correlated nearly as well as HbA1C 10-20 days after the glucose profile (r = 0.54-0.64, P less than 0.01-0.001), but only weakly after 25-35 days. Values for fructosamine did not correlate significantly with the glucose profile 10-35 days after it (r = 0.23-0.36). Evidently the fructosamine assay is not an adequate alternative to HbA1C, G-alb, or G-prot as an index to long-term control of blood glucose in such patients.
Investigation of sex-hormone binding globulin interference in direct radioimmunoassays for testosterone and estradiol.
Authors: Masters A M , Hähnel R 
Published: January 2020

Abstract
The aim of this study was to find reasons for the interference of sex-hormone binding globulin (SHBG) in direct radioimmunoassays (RIAs) for testosterone and estradiol. 125I-labeled testosterone and estradiol were compared with 3H-labeled testosterone and estradiol for their affinity to SHBG. The 3H-labeled steroids bound far more avidly to SHBG than did the corresponding 125I-labeled steroids. The SHBG concentration in the standard matrix of two kits was significant. Finally, 3H-labeled steroids were compared with 125I-labeled steroids for their affinity to the antibody supplied with the kits. The 125I-labeled steroids bound more avidly than did the 3H-labeled steroids to the corresponding antibodies. Direct testosterone and estradiol results would be influenced according to the SHBG in the sample, as observed.
Generalized likelihood ratio concept and logistic regression analysis for multiple diagnostic categories.
Authors: Reibnegger G , Fuchs D , Hausen A , Werner E R , Werner-Felmayer G , Wachter H 
Published: January 2020

Abstract
Albert (Clin Chem 1982;28:1113-9) has proposed estimation of likelihood ratios by logistic regression analysis. The usual likelihood-ratio approach for estimation of post-test probability of disease from sensitivity and specificity data of a diagnostic test has been extended by Birkett (J Clin Epidemiol 1988; 41:491-4) for situations with more than two diagnostic categories. We suggest here a combination of these ideas, demonstrating this by a re-evaluation of previously published data on the validity of neopterin as a tool for differential diagnosis between chronic non-A, non-B hepatitis and fatty liver. Analysis of neopterin data in combination with the ratio between serum concentrations of aspartate aminotransferase and of alanine aminotransferase yielded a good discrimination between three mutually exclusive diagnostic categories, namely, fatty liver and chronic persistent and chronic aggressive non-A, non-B hepatitis. The approach is flexibly applicable to situations with different pre-test probabilities. The sum of estimated post-test probabilities deviates slightly from the sum of pre-test probabilities. This deviation is a function of the coefficients obtained in logistic regression, and an analytical expression for the deviation is given. The generalized likelihood-ratio approach appears promising in complex diagnostic situations when multiple diagnostic tests are available.
The use of GC/IR/MS for high-confidence identification of drugs.
Authors: Duncan W P , Deutsch D G 
Published: January 2020

Abstract
We describe the use of a combined gas chromatographic/infrared/mass spectrometric system to identify some common, clinically important drugs. Sensitivity for the serially configured combined system is demonstrated to be in the low nanogram range for strong infrared-absorbing compounds. Linearity for cocaine in the infrared detector was shown to have a correlation coefficient of 0.9914. Vapor-phase infrared spectra are shown to be very reproducible, which is important in identifying drugs such as the barbiturates. Finally, the two completely independent principles of infrared and mass spectral detection lend significant confidence to the correct identification of the various drugs from a single injection of sample.
Analysis of supplemented vitamin K1(20) in serum microsamples by solid-phase extraction and narrow-bone HPLC with multichannel ultraviolet detection.
Authors: Kirk E M , Fell A F 
Published: January 2020

Abstract
A sensitive method for the determination of vitamin K1(20) in serum microsamples (50 microL) has been developed, utilizing solid-phase extraction with C8 Bond-Elut columns and reversed-phase narrow-bore high-performance liquid chromatography [2.1 mm (i.d.), column] with a nonaqueous eluent. Recovery from serum (49 ng/mL) was 76% (n = 2). Peak homogeneity was assessed by photodiode array detection with absorbance ratio, spectral normalization, and transformation to the first- and second-derivative chromatograms. Calibration data at 248 nm over two ranges (20-200 ng/mL, 200-4000 ng/mL) varied linearly with concentration and were suitable for studies of vitamin K1 supplementation. By comparison with conventional columns, sensitivity was increased twofold.
The continuing need for quality assessment of cyclosporine measurement.
Authors: Johnston A , Marsden J T , Holt D W 
Published: January 2020

Abstract
The returns from the United Kingdom Cyclosporin Quality Assessment Scheme were analyzed for the period June 1987 to August 1988. During this time the number of laboratories in the Scheme increased from 102 to 124 and the proportion of laboratories using nonspecific assay methods declined, as did the proportion of them measuring cyclosporine in plasma. Seven different methods were used to measure the drug in blood, and the seven methods gave seven different results when used to measure patients' samples. The results, from lowest to highest, differed by a factor of approximately 3.4. The within-assay coefficient of variation (CV) was acceptable for all methods, but the between-assay and between-center CVs were poor. HPLC gave higher CVs than did the immunoassays.
Issues in methodology and applications for therapeutic monitoring of antidepressant drugs.
Authors: Orsulak P J , Haven M C , Burton M E , Akers L C 
Published: January 2020

Abstract
Measurement of antidepressant drugs in serum provides a useful indicator of optimal dosage and can enable the clinician, in certain circumstances, to easily adjust dosages for individual differences in drug metabolism, alterations in the concentration in serum owing to drug interactions, or failure to achieve an adequate concentration in serum because of noncompliance. Practical therapeutic monitoring of antidepressants, however, is still complicated by a lack of suitable reference methodology or established assay-performance criteria and the diversity of analytical techniques. We review here several contemporary methods of analysis for the tricyclic antidepressant drugs--including gas chromatography with a nitrogen-specific detector, HPLC, and immunoassays--that are available for toxicology screening or for quantifying the most widely monitored tricyclic drugs. We also present an overview of current laboratory issues and practical considerations facing those who analyze for antidepressant drugs.
An update on digoxin.
Authors: Stone J A , Soldin S J 
Published: January 2020

Abstract
This review deals briefly with recent developments in the therapeutic drug monitoring of digoxin. Strategies for decreasing the interference by digoxin metabolites, digoxin-like factors, and spironolactone metabolites in immunoassays of digoxin are discussed. Other issues addressed include the development of alternative methods of analysis, such as receptor assays and "high-pressure" liquid chromatography; digoxin-like factors in hypertension; drug-drug interactions; redistribution of digoxin stores in the body; and forensic considerations.
The relevance of pharmacokinetics to monitoring new antiarrhythmics.
Authors: Holt D W , Johnston A 
Published: January 2020

Abstract
The application of selective and sensitive methodology to the investigation of the pharmacokinetics of new antiarrthythmic drugs is described. The value of these data in the context of routine measurements as a guide to therapy is discussed. In particular, specific case histories that demonstrate the considerable within- and between-subject variation in pharmacokinetic parameters are cited and used to illustrate the potential benefits of drug monitoring. We conclude that studies designed to elucidate the pharmacokinetics of these drugs in a variety of clinical settings can be a valuable guide to assessing the patient groups for whom routine monitoring would be of particular benefit when the drugs are in general clinical use.
Microplate measurement of urinary albumin and creatinine.
Authors: Magnotti R A , Stephens G W , Rogers R K , Pesce A J 
Published: January 2020

Abstract
We describe microplate methods for measurement of human urinary albumin (HUA) by competitive enzyme-linked immunosorbant assay (ELISA) and creatinine with a modified commercial enzymatic kit. Incorporation of substrate mixing into the competitive ELISA changes the dynamic absorbance-concentration response, greatly simplifying calculations and improving sensitivity and accuracy. Measurement of creatinine in urine and plasma samples with a commercially available enzymatic kit modified for analysis by use of an inexpensive microplate reader produced values comparable in precision and accuracy to those obtained by an automated kinetic Jaffé method.
Use of a dual-precipitation procedure for measuring high-density lipoprotein 3 (HDL3) in normolipidemic serum.
Authors: Cloey T A , Bachorik P S 
Published: January 2020

Abstract
We compared results by a dual-precipitation method (J Lipid Res 1982;23:1206-23) for measuring high-density lipoprotein 3 (HDL3) cholesterol with those by ultracentrifugation at d 1.125, using 56 fresh and 105 frozen-stored serum samples. For both methods, HDL2-cholesterol was calculated as the difference between total HDL-cholesterol and HDL3-cholesterol. In general, for pooled serum samples, agreement was closest with ultracentrifugation when we used a dextran sulfate concentration of 5.0 mg/L to precipitate the HDL2-rich fraction, although the optimal concentration varied from 3.0 to 6.8 mg/L for different pools. For individual samples, the values for HDL3 by dual precipitation averaged 12.8% lower than by ultracentrifugation. The coefficients of correlation between the two methods were HDL3, r = 0.70; and HDL2, r = 0.92. The dual-precipitation method reflected the expected sex-related differences in HDL2-cholesterol concentration and inverse relationship with triglyceride concentration.
Evidence that the oral glucose-tolerance test does not provide a uniform stimulus to pancreatic islets in pregnancy.
Authors: de Leacy E A , Cowley D M 
Published: January 2020

Abstract
Fifty consecutive pregnant patients referred for a glucose-tolerance test were classified on the basis of increasing (n = 20) or decreasing (n = 28) hematocrit after an oral 75-g glucose load. (The hematocrit did not change in the other two patients.) Patients with increasing hematocrit, a response previously seen in patients with the dumping syndrome, showed significantly flatter increases in glucose concentrations in plasma after the load. The mean decrease in the concentration of phosphate in plasma, measured as an index of glucose uptake by cells, was significantly less (P less than 0.05) 2 h after the load in the group with flatter glucose responses, suggesting that the flat response is ascribable to poor glucose absorption rather than to an exaggerated insulin response. These results indicate that the oral glucose-tolerance test stresses the pancreatic islets differently in different pregnant subjects, owing to individual variations in the gastrointestinal handling of the glucose load. Consequently, patients may give a "normal" result who might otherwise become hyperglycemic after normal meals. We suggest that alternative screening procedures be investigated to assess pregnant patients postprandially.
Interaction of immobilized anti-salivary amylase antibody with human macroamylases: implications for use in a pancreatic amylase assay to distinguish macroamylasemia from acute pancreatitis.
Authors: Mifflin T E , Forsman R W , Bruns D E 
Published: January 2020

Abstract
We examined the ability of an immobilized antibody to salivary amylase (Clin Chem 1985;33:1283-8) to react with amylase in macroamylasemic sera. The antibody removed 50% (SD 23%) of the total amylase activity from 39 macroamylase sera, a percentage indistinguishable (P greater than 0.75) from the percentage removed from concurrently analyzed sera from healthy volunteers (49%, SD 11%). Electrophoretic analysis of 23 macroamylasemic sera revealed that the antibody removed only part of the macroamylase band(s) in 71% of the cases. We conclude that the mean isoenzyme composition of the macroamylase complexes is essentially identical to the mean isoenzyme distribution in normal sera (i.e., about half salivary and half pancreatic amylase). Further, the immobilized antibody can be used to distinguish most patients with macroamylasemia from those with acute pancreatitis, because sera from the latter contain an increased proportion (greater than 80%) of pancreatic amylase.