bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoreactive pancreatic phospholipase A2 and catalytically active phospholipases A2 in serum from patients with acute pancreatitis.
Authors: Eskola J U , Nevalainen T J , Kortesuo P 
Published: January 2020

Abstract
Measuring the content of immunoreactive pancreatic phospholipase A2 (PLA2; EC 3.1.1.4) and the catalytic activity of PLA2 in serum samples from five patients with acute pancreatitis, we found no correlation between these two measurements overall. To test the specificity of the method for catalytic PLA2, we measured PLA2 activity in serum samples before and after immunoadsorption with an antiserum to human pancreatic PLA2. The results suggest the presence of at least two immunologically distinct PLA2 enzyme proteins in sera from these patients. One of the enzymes is pancreatic in origin and may exist in active, inactive, or inhibited form. The activity profile of the second PLA2 enzyme in serum during acute pancreatitis differs from that for other common pancreatic enzymes. In the present experiment, the catalytic activity was not removed by treatment with the anti-human pancreatic PLA2 antiserum. The source of this second PLA2 activity is unknown. Some samples contained increased activities of both PLA2 forms.
Opioid peptide profile in human pituitary.
Authors: Desiderio D M , Fridland G H , Francisco J T , Sacks H , Robertson J T , Cezayirli R C , Killmar J , Lahren C 
Published: January 2020

Abstract
The comprehensive metabolic profile of endogenous opioid peptides is established here for human pituitary for the first time. Sixteen human pituitaries, obtained postmortem, were analyzed individually by gradient reversed-phase high-performance liquid chromatography together with a radio-receptor assay with [3H]etorphine as ligand. This combination was used to detect opioid receptor activity. The 16 assay profiles were sufficiently consistent for a composite of them to serve as a comparative basis for other studies on the pathophysiology of the human pituitary. To demonstrate one selected comparison, we present data on a distinctively different profile of opioid receptor activity in the pituitary of one patient who died from a drug overdose.
Revised calibration of the Reflotron cholesterol assay evaluated.
Authors: Boerma G J , van Gorp I , Liem T L , Leijnse B , Bellm J , Carstensen C A 
Published: January 2020

Abstract
We evaluated the Boehringer Mannheim (B.M.) Reflotron Total Cholesterol "dry-chemistry" method after its recalibration in 1987. Reports in the literature up to 1986-1987 of a negative bias (up to -10%) in the method prompted a revision of the factory-set calibration of the Reflotron. For this, B.M. prepared a new set of calibrators with 12 different concentrations of cholesterol. We checked in two ways whether accuracy had been achieved: (a) The values assigned to the calibrators by B.M. were checked with the manual Abell-Kendall Reference Method (MAK) performed in an official Reference Center. These were shown to be correct. (b) Concurrently, a direct comparison was made by analyzing 200 fresh samples of human serum. Reflotron cholesterol values obtained for these samples proved to be accurate, meeting the current World Health Organization/Centers for Disease Control criterion of maximum bias less than or equal to 5%. Orthogonal regression analysis yielded the following correlation: Reflotron = 0.985 MAK + 0.238 mmol/L (y = ax + b). Reflotron mean = 6.26 mmol/L; MAK mean = 6.09 mmol/L. SDa = 0.015 mmol/L; SDb = 0.120 mmol/L, and r = 0.989.
A review on the methodology for assessing diagnostic tests.
Authors: Linnet K 
Published: January 2020

Abstract
Evaluation of diagnostic tests by the following principles are reviewed: error rates, scores based on posterior probabilities, and the excess loss considered in a decision theoretic context. Error rates or the complementary non-error rates, specificity and sensitivity, are simple measures which provide a rough indication of the discriminative value. In clinical practice, where a test serves as a decision support together with other information, conversion of test results to posterior probabilities is recommended. An aggregate score of these probabilities expresses the value of the test. Finally, in simple, well-defined cases--for example, screening situations, where the prevalence of disease and the relative consequences of false-positive and -negative classifications can be estimated--a Bayesian decision analysis is appropriate. The optimal discrimination limit is selected, and the total loss is minimized. The likelihood ratio LR(x) plays a central role in probability calculations and in the decision analysis. An example illustrates application of the procedures.
Particle counting immunoassay of S100 protein in serum. Possible relevance in tumors and ischemic disorders of the central nervous system.
Authors: Fagnart O C , Sindic C J , Laterre C 
Published: January 2020

Abstract
S100 protein (S100) was assayed by particle counting immunoassay in serum samples from 50 healthy individuals, 325 patients with various neurological disorders, and 20 patients with malignant melanoma. The detection limit for this protein was 0.3 microgram/L. We detected none in healthy individuals or in 50 patients with multiple sclerosis, 23 with dementia, or 20 with meningitis. S100 was detectable in serum of only a few patients with meningoradiculitis (2/20), peripheral neuropathy (2/30), encephalitis (1/14), Guillain-Barré syndrome (1/25), or AIDS (2/20). In contrast, we observed high concentrations in 29 of 75 patients with tumors of the central nervous system, especially in meningioma (6/9), glioblastoma (9/23), and neurinoma (5/5). Values for S100 were mainly abnormally high (greater than 0.3 microgram/L) in serum from patients with cerebrovascular disorders (43/48) or with metastases of melanoma (9/11).
Rendering the "poppy-seed defense" defenseless: identification of 6-monoacetylmorphine in urine by gas chromatography/mass spectroscopy.
Authors: Mulé S J , Casella G A 
Published: January 2020

Abstract
We report a sensitive, rapid, quantitative gas chromatographic/mass spectroscopic method for measuring the 6-monoacetylmorphine (6-MAM) metabolite of heroin in 0.5 mL of human urine. After a simple liquid-liquid extraction and derivatization, the trimethylsilyl derivative of 6-MAM is identified from its retention time (total ion current) and by selected ion monitoring. The limit of detection was 10 micrograms/L, corresponding to 0.2 ng of trimethylsilyl-6-MAM injected into the gas chromatograph/mass spectrometer. The presence of 6-MAM in urine is indicative of heroin. 6-MAM is not present in poppy seeds or in urine after the ingestion of products containing poppy seed.
Reference values for nucleosides and nucleobases in cerebrospinal fluid of children.
Authors: Gerrits G P , Haagen A A , De Abreu R A , Monnens L A , Gabreëls F J , Trijbels F J , Theeuwes A L , van Baal J M 
Published: January 2020

Abstract
Disturbances in the metabolism of purines and pyrimidines in neurologically affected patients can be reflected by aberrant concentrations of nucleosides and nucleobases in cerebrospinal fluid (CSF). However, normal values, especially for children at different ages, are lacking. We collected 1000 specimens of CSF from subjects ranging in age from newborn to 18 years, who were undergoing a diagnostic lumbar puncture for several clinical indications. Of these, 78 samples could be used retrospectively as a reference according to our criteria. The analyses were performed with a modified HPLC procedure. None of the substances shows age-dependency except uridine and uric acid. Uridine increases with age, and uric acid increases with age in boys older than 12 years.
Chemistry profiles in "wellness programs": test selection and participant outcomes.
Authors: Witte D L , Angstadt D S , Schweitzer J K 
Published: January 2020

Abstract
Insurers, employers, and individuals create demands for laboratory testing in "wellness programs." Tests chosen to identify cases deserving intervention included routine automated chemical tests plus high-density lipoprotein cholesterol, ferritin, and thyroid tests. Participants' unwarranted concerns were addressed with a personalized reporting schema. We tested 1338 individuals, identified 224 (16.7%) with significant abnormalities, and made phone contact follow-up with 193 (86%) of these six to 14 months later. Cholesterol results suggesting increased risk of heart disease were frequent, and were not studied. Interventions were initiated in 55 of the 193 followup cases (49 by physician and six by participants), including prescription of iron or thyroid hormone, counseling on dietary or alcohol intake, and repeat testing. For 58, there was medical advice without intervention; abnormal results were ignored by 79. Noteworthy participant anxiety was manifested in two of the 193 cases, both of whom were treated with iron. We conclude that 4% of the original 1338 participants potentially benefitted from intervention. Ferritin and thyroid tests initiated 33 (61%) of these 55 specific therapeutic interventions.
Accumulation of glycolic acid and glyoxylic acid in serum in cases of transient hyperglycinemia after transurethral surgery.
Authors: Perier C , Frey J , Auboyer C , Richard A , Aulagnier G , Heritier P , Gilloz A 
Published: January 2020

Abstract
Experimental data are presented here proving the accumulation of glycine in serum after transurethral prostatectomy and increased production of glycine metabolites: serine, alanine, glyoxylic acid, and glycolic acid. The presence of the metabolites glyoxylic acid and glycolic acid was demonstrated by gas-liquid chromatography and mass spectrometry. Glycine, glyoxylic acid, and glycolic acid possess neurological activity, so we examined the pathophysiology of the transurethral prostatectomy syndrome in view of the transient accumulation of these compounds in serum.
The potency of immunoglobulin G fragments for inhibition of interference caused by anti-immunoglobulin antibodies in a monoclonal immunoradiometric assay for thyrotropin.
Authors: Csako G , Weintraub B D , Zweig M H 
Published: January 2020

Abstract
Heterophile antibodies in patients' serum may produce false increases in apparent analyte concentrations in "sandwich"-type immunoassays. Using three patients with endogenous anti-mouse IgG antibodies and a two-site mouse monoclonal assay for thyrotropin, we studied the ability of IgG fragments to block this positive interference. Mouse whole IgG and IgG Fc fragment blocked the interference virtually completely; IgG F(ab')2 and Fab fragments did not. Rat and horse immunoglobulin fragments gave variable results. We suggest that sandwich assays formulated with IgG Fab or F(ab')2 fragments may be less susceptible to positive interference by heterophile antibodies. Unlike sera from the three patients, simulated human specimens containing heterologous anti-IgG antibodies showed little or no selectivity in inhibition by IgG fragments, and therefore are not useful to study this phenomenon.
Influence of hypertension and antihypertensive drugs on the biological intra-individual variation of electrolytes and lipids in serum.
Authors: Hölzel W G 
Published: January 2020

Abstract
Biological intra-individual CVs for Na+, Cl-, K+, calcium, cholesterol, high-density lipoprotein cholesterol, triglycerides in serum, and hemoglobin in blood were estimated in men with essential hypertension (EH) treated with beta-blockers and diuretics, and compared with those of normotensive men. Although in EH the mean concentrations of Na+, Cl-, K+, hemoglobin, and triglycerides were increased and that of HDL cholesterol was decreased, the average intra-individual CVs did not significantly differ between the two groups. The mean concentration of cholesterol, as well as the average intra-individual CV for it, was significantly higher in EH. There was no correlation between the intra-individual CVs for the analytes and the mean blood pressure of the individuals. Individual values were normally distributed for all analytes. There was no increase of the intra-individual CV with the lapse of time between consecutively measured values. The estimated average biological intra-individual CV was used to derive decision-making criteria for interpretation of test results observed in monitoring EH.
Total creatine kinase (CK) and CK-B activity in maternal blood and cord-blood samples after vaginal and cesarean births.
Authors: Liras G , Diaz V , Alvarez C , Arenas J , Sanz R , Martinez V 
Published: January 2020

Abstract
We studied variations in the activity of total creatine kinase (CK; EC 2.7.3.2) and of CK-B in maternal and cord-blood samples, comparing data obtained for vaginal and cesarean births. CK-B activity was determined with an immunoinhibition assay. In all cases, there was a significant postpartum increase in total CK and in CK-B activity in maternal sera, whereas cord-blood samples showed no significant differences between activities in arterial and venous blood for either vaginal or cesarean births. Statistically significant differences were found in CK-B activity, but not in total CK, between cord-blood samples from vaginal births and those from cesareans.
Determination of oxalate concentration in blood.
Authors: Costello J , Landwehr D M 
Published: January 2020

Abstract
The methods used for determination of oxalate in blood are reviewed, and the advantages and disadvantages of the two basic approaches--direct methods and in vivo isotope-dilution techniques--are compared. Possible reasons for the previous discrepancies between direct and isotopic methods are discussed, as are the effects of protein binding, sample handling, and storage conditions on oxalate values in plasma. Necessary precautions for obtaining reproducible results are presented. We recommend and critically review several direct methods, and describe the application of a direct method for oxalate determination in some other biological fluids.
Survey of alpha-amylase activity and isoamylases in autopsy tissue.
Authors: Whitten R O , Chandler W L , Thomas M G , Clayson K J , Fine J S 
Published: January 2020

Abstract
We quantified total amylase and its isoenzymes in 22 different human tissues obtained at autopsy. Isoenzymes were separated by use of wheat-germ inhibition (WI) and electrophoresis on cellulose acetate (CA) and agarose (AG). Mean (+/- SD) total activity was highest in salivary glands (parotid 1710 +/- 897 U/g, submandibular 605 +/- 354 U/g), and pancreas (258 +/- 137 U/g). All other tissues contained 100- to 1000-fold less amylase. As assessed with WI, pancreas, jejunum, liver, placenta, testis, skeletal muscle, and spleen contained more than 90% pancreatic isoamylase. Salivary glands and thyroid contained more than 90% salivary isoamylase. All other tissues contained a mixture of the two isoenzymes. CA and AG often produced different results. For both CA and AG the most common pancreatic isoforms were P2 and S1. Salivary gland homogenates demonstrated a band migrating in the P3 position on CA. We conclude that both types of amylase isoenzymes can be found in tissues other than salivary gland and pancreas, but that their low total amylase concentrations diminish their clinical importance.
A competitive enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in serum and urine samples.
Authors: Phillips A , Rowell F J 
Published: January 2020

Abstract
In this solid-phase competitive enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in serum or urine, antiserum to human alpha 1-acid glycoprotein is incubated with solid-phase-bound alpha 1-acid glycoprotein in the presence of standard or sample. Incubation with second antibody labeled with alkaline phosphatase then follows, before development with substrate. Results obtained correlate well with a fluorescent assay involving the dye Auramine O (r = 0.953) and with radial immunodiffusion (r = 0.921). The present assay covers the range 0.2 to 5 mg/L and 16 samples take 2.5 h to complete. This assay is useful for measuring concentrations of alpha 1-acid glycoprotein in serum and also in urine, for which other assay methods are not sufficiently sensitive.
Analytical performance of three commercially available nephelometers compared for quantifying proteins in serum and cerebrospinal fluid.
Authors: Salden H J , Bas B M , Hermans I T , Janson P C 
Published: January 2020

Abstract
We investigated the analytical performance and imprecision of three commercially available nephelometers for the quantification of various proteins in pooled serum and cerebrospinal fluid. Albumin, transferrin, IgG, IgA, and IgM in serum were determined nephelometrically (BNA, Behring; Array, Beckman) and turbidimetrically (Cobas Bio, Hoffmann-La Roche). All these proteins in cerebrospinal fluid except transferrin were determined nephelometrically with all three systems. CVs and lower limits of detection were compared for all instruments, and stability of calibration curves was evaluated.
Screening urine before microscopy, by automated test-strip preselection: clinical evaluation of the improved Rapimat II/T (Behring).
Authors: Kutter D , Braun C , Gallego F , Stirn-Thoma S 
Published: January 2020

Abstract
In many laboratories, microscopy of urines is restricted to specimens selected on the basis of positive tests, mainly for protein, blood, nitrite, and leukocyte esterase. Here, we analyzed several hundred specimens by use of multiple dipsticks, read in an improved reflectometer. By comparing the results with quantitative microscopy, it could be shown that this system allows selection, with acceptable sensitivity and specificity, of those specimens that are likely to contain clinically important microscopic elements.
An international quality-assessment program for measurement of aluminum in human plasma: a progress report.
Authors: Guillard O , Pineau A , Baruthio F , Arnaud J 
Published: January 2020

Abstract
In view of the increasing interest in measurement of aluminum in plasma of hemodialysis patients and the analytical difficulties, which may lead to false clinical interpretations, we organized an international interlaboratory quality-control program that has operated since 1983. The results obtained after four years (72 participants) demonstrate a lessened discrepancy of the results. This program allowed some laboratories to improve their results and even to solve some of their analytical problems. This surveillance will be continued and extended to include the analysis of dialysis fluids.
Interlaboratory proficiency survey of cholesterol and high-density lipoprotein cholesterol measurement.
Authors: McMillan T A , Warnick G R 
Published: January 2020

Abstract
We conducted a proficiency survey of cholesterol and high-density lipoprotein (HDL) cholesterol analysis in local clinical laboratories to determine whether increased national emphasis on cholesterol measurement had resulted in changes in performance from previous surveys. Sets of frozen aliquots of plasma and HDL supernate pools were sent to nine laboratories for analysis; results were compared with Northwest Lipid Research Center values, and relationships were determined by linear regression. Of all the cholesterol measurements, 81% were considered acceptable (i.e., within 9% of the NWLRC value), and 61% of the HDL cholesterol measurements were considered acceptable (within 50 mg/L of NWLRC values). These data represented no improvement over previous surveys. Workload had increased significantly: 79% for cholesterol and 284% for HDL cholesterol. On a bias plot, six of the laboratories demonstrated inaccuracy greater than the +/- 3% recommendation within the critical range of 2000-2400 mg/L for total cholesterol. For HDL cholesterol, two laboratories demonstrated bias greater than 10% at the critical point of 350 mg/L, with three additional laboratories displaying strong bias outside the decision point. The survey results indicate that apparently further improvements must be made for laboratories to achieve acceptable performance in cholesterol analysis.
Wheat-germ agglutinin method for measuring bone and liver isoenzymes of alkaline phosphatase assessed in postmenopausal osteoporosis.
Authors: Sørensen S 
Published: January 2020

Abstract
In the method of Rosalki and Foo (Clin Chem 1984;30:1182-6) bone and liver isoenzymes of alkaline phosphatase (EC 3.1.3.1) are quantified by using wheat-germ agglutinin (WGA). I suggest standardizing the procedure by using a WGA concentration that precipitates half of the alkaline phosphatase activity of serum pooled from an equal number of healthy women and men. By applying knowledge of the precipitation pattern in serum samples containing predominantly or exclusively bone or liver sources of alkaline phosphatase, I obtained results for the isoenzymes in healthy subjects that agreed with those by the heat-inactivation methods, as reported earlier in the literature. I then assessed the utility of the standardized procedure in a clinical study of prevention of postmenopausal bone loss. In patients receiving hormone replacement therapy, which is known to decrease bone turnover, the decrease in total alkaline phosphatase activity in serum was entirely ascribable to decreases in the bone isoenzyme activity, probably reflecting reduced bone formation, whereas the activity concentration of liver alkaline phosphatase remained unchanged.
High-density lipoprotein apolipoproteins in urine: II. Enzyme-linked immunoassay of apolipoprotein A-I.
Authors: Gomo Z A , Henderson L O 
Published: January 2020

Abstract
We have developed a capture antibody, noncompetitive, enzyme-linked immunoassay for urinary apolipoprotein A-I (Apo A-I) in urine, with use of affinity-purified polyclonal antisera against Apo A-I. A 96-well microtiter plate format is used, with unconcentrated urine as sample and dilutions of serum or high-density lipoprotein (HDL) as standards. The intra- and interassay variation (CV) averaged 7.4% and 9.4%, respectively. The limit of detection is low (1.25 ng/L), and no cross-reactivity with Apo B, C, E, or A-II was detected. The mean (+/- SD) concentrations of Apo A-I in urine of patients with glomerular proteinuria were a thousandfold greater (38.4 +/- 23.1 mg/L) than in normal subjects (16.3 +/- 11.3 micrograms/L in men, 17.97 +/- 7.7 micrograms/L in women, a significant difference, P less than 0.001). Apo A-I measurements correlated very well (r = 0.92) with selectivity index assessment. The diurnal variation of the concentration of Apo A-I in urine appears to result from dilution related to fluid intake. This enzymatic method is easy to perform, can be used with large numbers of samples, and is adaptable for use in the routine clinical laboratory. The method holds promise for discriminating between normal and subclinical kidney disease populations by measuring the concentrations of urinary Apo A-I excreted on HDL particles.
Plasma amino acid pattern of patients with HIV infection.
Authors: Ollenschläger G , Jansen S , Schindler J , Rasokat H , Schrappe-Bächer M , Roth E 
Published: January 2020

Abstract
We measured the free amino acids in plasma of 58 patients with HIV infection and in six persons in the risk group. The HIV+ patients had significantly increased concentrations of arginine, phenylalanine, and glutamate in comparison with both age- and sex-matched controls and the members of the risk group. Glutamate concentrations increased only in an advanced stage of the disease (WR 5 and 6 of the Walter Reed staging classification), whereas arginine and phenylalanine increased independently of the stage. There was no correlation between the amino acid concentrations and the number of T4 and T8 lymphocytes, the sedimentation rate, and the existence or absence of Kaposi's sarcoma. The amino acid pattern of HIV-infected persons is similar to that of cancer patients or those with other immune deficiencies.