bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of Elastase and Cysteine Proteinases in Synovial Fluid of Patients with Rheumatoid Arthritis, Sero-Negative Spondylarthropathies, and Osteoarthritis
Authors: Huet G , Flipo R M , Richet C , Thiebaut C , Demeyer D , Balduyck M , Duquesnoy B , Degand P 
Published: January 2020

Abstract
Synovial fluid samples were collected from 45 patients with rheumatoid arthritis, spondylarthropathy, or osteoarthritis, to study their content of elastase (EC 3.4.21.37) and of cysteine proteinases (EC 3.4.22.1, 3.4.22.15). We measured both elastase complexed with alpha 1-proteinase inhibitor and elastase activity toward the substrate L-pyroglutamyl-L-prolyl-L-valine-p-nitroanilide. Cysteine proteinase activities were measured with the substrates N-benzyloxycarbonyl-L-phenylalanyl-L-arginine-7-amido-4-methylcoumarin (Z-Phe-Arg-AMC) and Z-Arg-Arg-AMC and the inhibitor E-64 [L-trans-epoxysuccinyl-leucyl-amido-(4-guanidino)-butane]. In all these enzyme assays, higher median values were obtained in inflammatory arthropathies than in osteoarthritis. The concentration of the elastase-alpha 1-proteinase inhibitor complex and of elastase and cysteine proteinase activities were statistically higher in patients with rheumatoid arthritis than in patients with osteoarthritis. The difference in results between patients with spondylarthropathy and patients with osteoarthritis was statistically significant only for the elastase-alpha 1-proteinase inhibitor complex. The median values of the complex and of both enzyme activities were higher in patients with rheumatoid arthritis than in patients with spondylarthropathy; however, the difference was statistically significant only for the cysteine proteinase activity measured with Z-Arg-Arg-AMC substrate. These results suggest that both elastase and cysteine proteinases, which are increased in patients with inflammatory arthritis, are involved in cartilage degradation in these arthropathies.
Macroamylases: Differences in Activity against Various-Sized Substrates
Authors: Rosenblum J L , Hortin G L , Smith C H , Pashos G E , Landt M 
Published: January 2020

Abstract
Hyperamylasemia caused by macroamylases can lead to the overdiagnosis of acute pancreatitis. We examined whether interference from macroamylase is less in assays that use high-molecular-mass (high-M(r)) substrates rather than oligosaccharide substrates. We hypothesized that high-M(r) substrates would be sterically excluded from macroamylasemic complexes and thus would be hydrolyzed less efficiently. Eighteen macroamylasemic samples were assayed by using red-dyed amylopectin or blue-dyed starch as polysaccharide substrates or by using maltoheptaose or maltotetraose as oligosaccharide substrates. The oligosaccharide substrates gave comparable results (y = 0.81x + 83), but we observed consistently lower activities for amylopectin than for maltotetraose (y = 0.32x + 38). We observed no bias among methods when nonmacroamylasemic specimens were analyzed. The mechanism of this difference was examined by adding antihuman pancreatic amylase antibodies to hyperamylasemic serum samples from patients without macroamylasemia and to purified human pancreatic or salivary isoamylases. In each case, polyclonal and monoclonal antibodies lowered amylase activity more in assays with complex polysaccharides than in those with oligosaccharides. The use of high-M(r) substrates diminishes interference, and detection of suspected macroamylasemia may be possible through comparing activities determined from automated methods that use different substrates.
Increased Concentrations of Total IgM At Clinical Onset of Type 1 (Insulin-Dependent) Diabetes: Correlation with IgM Binding to Cells. The Belgian Diabetes Registry
Authors: Decraene T , Vandewalle C , Pipeleers D , Gorus F K 
Published: January 2020

Abstract
Eighty patients with type 1 (insulin-dependent) diabetes (ages 0-39 years) were consecutively recruited by the Belgian Diabetes Registry. Sera obtained at clinically diagnosed onset (i.e., before start of insulin therapy or within 7 days of initial treatment) were analyzed for total IgM concentrations and for IgM binding to fixed rat splenocytes (IgM-LyAb) and permeabilized rat islet cells (IgM-ICAb). Comparison of results with those in age- and sex-matched control subjects, by fluorescence-activated cell-sorter analysis, indicated greater concentrations of IgM-LyAb and IgM-ICAb in sera from the patients. IgM antibodies reacted indiscriminately with islet beta and islet endocrine non-beta cells. The prevalence of IgM-ICAb, but not of IgM-LyAB, was significantly (P less than 0.05) higher in patients than in the control subjects. Of the ICAb-positive patients, 54% were also LyAb-positive, whereas none of the control subjects were doubly positive. IgM-ICAb and IgM-LyAb binding signals were positively correlated. Serum IgM concentrations were significantly (P less than 0.001) greater in patients than in control subjects and were significantly correlated with IgM-LyAb (P less than 0.001) and IgM-ICAb (P less than 0.01). The positivity for IgM binding was not, however, merely a reflection of total IgM, because no such correlation was found in sera from seven patients with Waldenström macroglobulinemia. Clinical onset of type 1 diabetes is apparently accompanied by increased production of IgM. The correlation between IgM concentrations and IgM binding to islet cells might reflect polyclonal activation or natural autoantibodies.
Minimum Distinguishable Difference in Concentration: A Clinically Oriented Translation of Assay Precision Summaries
Authors: Sadler W A , Murray L M , Turner J G 
Published: January 2020

Abstract
A trend to market-driven health care in many parts of the world is focusing increasing attention on getting maximum value from available resources. Laboratories are not exempted. Well-informed clinical input has a potentially valuable role in any laboratory rationalization process. However, a communication difficulty exists in the sense that, although laboratory workers, commercial developers, regulatory bodies, etc., are thoroughly conditioned to using assay coefficient of variation as a general performance measure (for excellent reasons), this is not necessarily the most intuitive or informative scale from a clinician's perspective. Here we use routine clinical data from an immunoradiometric assay of thyrotropin to illustrate, first, a general approach to estimation and prediction of reproducibility, and second, an alternative summary that expresses the discriminatory power of an assay. This latter measure, our experience suggests, is more suited to the way clinicians perceive assays and assay results. The overall aim is improved clinician/laboratory communication.
Detection and Confirmation of Cocaine and Cocaethylene in Serum Emergency Toxicology Specimens
Authors: Puopolo P R , Chamberlin P , Flood J G 
Published: January 2020

Abstract
We report the performance of a liquid chromatography (LC) assay for detection and confirmation of cocaine and cocaethylene in serum. A photodiode array (PDA) detector monitors the cyano column effluent at 230 nm for analyte detection. Confirmation of a peak's identity is performed by use of only the 226-254-nm segment of the spectra rather than a broader range such as 210-340 nm. Use of the narrower range improves the assay's sensitivity by almost 10-fold. Analyte values of 10 micrograms/L are confirmed routinely. Intra-assay imprecision at 100, 20, and 10 micrograms/L for cocaine is 5.1%, 5.7%, and 6.6% (CV), respectively. Absolute recovery of the analytes exceeds 80%. In a split-sample study (33 positives and 74 negatives), each of this method's cocaine findings were confirmed. Cocaethylene was found in 15 of these samples. A complete chromatogram can be available 15 min after the start of the procedure. The method's focus on the active drug (rather than urinary metabolites) and its ability to detect and confirm many other drugs make it well suited for emergency toxicology testing.
Increased Concentrations of Type IV (7 S) Collagen in Sera of Hyperthyroid Patients with Graves Disease
Authors: Shima T , Yano Y , Goto H , Misaki M 
Published: January 2020

Abstract
Serum concentrations of type IV collagen (7 S) were determined in 29 patients with untreated hyperthyroidism and 30 healthy subjects. Serum 7 S collagen was significantly higher (P less than 0.0001) in the hyperthyroid patients (6.3, SD 1.3, micrograms/L) than in the healthy control subjects (3.9, SD 0.6, micrograms/L). No difference in serum concentrations of 7 S collagen were observed between patients with normal liver function and those with abnormal liver function. Serum concentrations of 7 S collagen correlated positively with serum concentrations of free triiodothyronine (r = 0.41, P less than 0.05). In the hyperthyroid patients, 7 S collagen concentrations in serum gradually fell into the normal range as thyroid function became normalized. Thus, hyperthyroidism is one of the diseases in which serum concentrations of 7 S collagen are increased.
Automated Capillary Electrophoresis Applied to Therapeutic Drug Monitoring
Authors: Evenson M A , Wiktorowicz J E 
Published: January 2020

Abstract
Chromatographic separations in conjunction with physical chemical detection methods can provide extremely accurate and highly precise measurements of drugs in biological matrices. Immunochemical methods for drug analyses, on the other hand, although usually fully automated, often lack accuracy, may be subject to matrix interference effects, and frequently exhibit nonlinearities that contribute to suboptimal analytical results. Automated capillary electrophoresis (CE) promises the high accuracy and precision of physical methods with no operator intervention once the sample is loaded into the sample cup. A clean-up step is necessary for the analysis of drugs in biological matrices, but that could also be fully automated. Reagent costs per test with CE approach zero, because of the use of extremely small volumes of buffers, standards, and controls. We present data supporting CE as an alternative separation strategy for 28 commonly used therapeutic drugs. These can be resolved in less than 16 min with an optimized micelle-based buffer system.
An Oral-Diffusion-Sink Device for Extended Sampling of Multiple Steroid Hormones from Saliva
Authors: Wade S E 
Published: January 2020

Abstract
Performance of a new oral-diffusion-sink (ODS) device for sampling the steroid hormones cortisol, progesterone, estradiol, and testosterone from human saliva was tested in vitro. The tested device differed from an earlier ODS sampler by using a polymeric composition of beta-cyclodextrin rather than an antiserum to bind analytes diffusing into the device. The capacity of the cyclodextrin-driven device to accumulate the steroid hormones from a simple buffer, human saliva, and saliva fortified with high concentrations of glucocorticosteroids was evaluated. Further, the ability of this device to accurately register the average analyte concentration resulting from treatments simulating physiological episodic secretion events was tested. Each steroid showed a characteristic rate of uptake that was unaffected by saliva or high physiological concentrations of competing steroids, and ODS uptake resulting from temporally varied concentrations of the hormone in the medium accurately reflected the time-integrated average concentration. This ODS provides a potential noninvasive and unobtrusive means of sampling the tissue-available concentrations of multiple steroid hormones, with averaging over physiological secretion events.
Analysis of Cholesterol in All Lipoprotein Classes by Single Vertical Ultracentrifugation of Fingerstick Blood and Controlled-Dispersion Flow Analysis
Authors: Kulkarni K R , Garber D W , Schmidt C F , Marcovina S M , Ho M H , Wilhite B J , Beaudrie K R , Segrest J P 
Published: January 2020

Abstract
This new, highly sensitive analytical system, based on controlled dispersion of the flowing sample, gives a rapid, continuous, and direct analysis for cholesterol in all lipoprotein classes, separated by single vertical-spin density-gradient ultracentrifugation. In this Vertical Auto Profile-II fingerstick system, designated VAP-IIfs, a narrow-bore Teflon coil serves as the reactor with no segmentation of the analytical stream by air bubbles, in contrast to the Technicon AutoAnalyzer used in the VAP-I method. Concentrations of high-, low-, intermediate-, and very-low-density lipoprotein cholesterol and lipoprotein(a) cholesterol are determined by decomposing the spectrophotometric absorbance curve for the continuous analysis of the centrifuged sample, with use of software developed in this laboratory. Total cholesterol is determined from the total area under the absorbance curve. For assaying total cholesterol, the CV between aliquots within a rotor ranged from 1.35% to 3.15%; the CV between rotors was 2.45%. Because only 18 microL of sample is required, VAP-IIfs can be readily adapted to analysis for lipoprotein cholesterol profiles in capillary blood samples. Total cholesterol values by VAP-IIfs for fingerstick and venous samples from 23 subjects agreed well: slope = 1.01 (SD 0.03), intercept = -21 (SD 51) mg/L, Sy/x = 50 mg/L, and r = 0.992. Results by VAP-IIfs also correlated highly with results for duplicate samples analyzed at the Northwest Lipid Research Laboratories.
Analytical performance evaluation of EMIT II monoclonal amphetamine/methamphetamine assay: more specificity than EMIT d.a.u. monoclonal amphetamine/methamphetamine assay
Authors: Dasgupta A , Saldana S , Kinnaman G , Smith M , Johansen K 
Published: January 2020

Abstract
We evaluated a new EMIT II monoclonal amphetamine/methamphetamine assay for screening human urine by comparing it with the EMIT d.a.u. monoclonal amphetamine/methamphetamine assay and a fluorescence polarization assay. The EMIT II assay has a cutoff of 1 mg/L d-methamphetamine. The EMIT II and EMIT d.a.u. assays were run on a BM/Hitachi 704 analyzer; for the fluorescence polarization assay we used a TDx analyzer. All EMIT II positive samples were also analyzed by the fluorescence polarization assay. We used gas chromatography/mass spectrometry (GC/MS) for confirmation of the presence of amphetamine or methamphetamine. Within-run CVs for the Level 1 (1 mg/L) and Level 2 (3 mg/L) calibrators for the EMIT II assay were 0.47% and 0.53%, respectively. Corresponding between-run CVs were 1.48% and 1.60%, respectively. Of the 1007 samples screened for amphetamines, 50 were positive by the EMIT d.a.u. assay; 21 samples (not a subset of the 50 samples) were positive by the EMIT II assay. However, 19 samples that tested positive by EMIT II also tested positive by the EMIT d.a.u. assay. Subsequent testing of the EMIT II positive samples by the fluorescence polarization assay detected in six positive samples. By means of chiral derivatization wer identified two specimens containing primarily l-isomers of amphetamine and methamphetamine. Sympathomimetic amines were identified in several of the samples not containing amphetamine or methamphetamine.
Discordant results for determinations of triglycerides in pig sera
Authors: Tuten T , Robinson K A , Sgoutas D S 
Published: January 2020

Abstract
We recently determined triglyceride concentrations in pig sera by three fully enzymatic methods (Kodak Ektachem 700, Hitachi 707, and Abbott EPx) and obtained significantly lower values than those obtained with chemical or enzymatic methods based on chemical hydrolysis. All methods used involve microbial lipases for liberating glycerol from glycerides and glycerol phosphate dehydrogenases or oxidases for subsequent oxidation. The methods were validated against reference methods by using fresh human sera and survey materials. The discordant results were not from matrix sample-method interaction but from incomplete hydrolysis of pig serum triglycerides by the lipolytic enzymes. When serum triglycerides from 10 pigs showing the highest biases were hydrolyzed by microbial lipases and the reaction mixture was subjected to thin-layer and gas-liquid chromatography, the predominant end products were palmitoyl monoglyceride and a mixture of free fatty acids with the following composition (fatty acid as percent of total +/- SD): 16:0, 7.8 +/- 2; 18:0, 5.4 +/- 2.2; 18:1, 53 +/- 12; 18:2, 31 +/- 4.6; and 18:3, 2.5 +/- 1. Assuming that the lipases exhibit the usual specificity toward the 1 and 3 positions of the triglyceride, the data suggest that, in pig, triglycerides 18:1 and 18:2 occupy the 1 and 3 positions and 16:0 (palmitic acid) predominantly occupies the 2 position. Triglycerides of this structure may not be well hydrolyzed by the typical lipolytic enzymes in clinical assays.
Phenylalanine determined in plasma with use of phenylalanine dehydrogenase and a centrifugal analyzer
Authors: Vilaseca M A , Farré C , Ramón F 
Published: January 2020

Abstract
Quantitative determination of plasma phenylalanine (Phe) is essential for the diagnosis of phenylketonuria (PKU) and the control of dietary therapy of PKU patients. We have adapted a spectrophotometric method (Clin Chim Acta 1991;201:95-8) based on phenylalanine dehydrogenase (EC 1.4.1.-) for rapid and accurate determinations of Phe with the Cobas Fara II centrifugal analyzer. The method is based on the NAD(H)-dependent reductive deamination of Phe with large amounts of phenylalanine dehydrogenase, which catalyzes the formation of phenylpyruvate at pH 10.8. Combining the specificity of the phenylalanine dehydrogenase with the precision, accuracy, and considerable time-saving of an automated system is useful for monitoring PKU patients in a children's hospital.
Robotic chromatography: development and evaluation of automated instrumentation for assay of glycohemoglobin
Authors: Herold C D , Andree K , Herold D A , Felder R A 
Published: January 2020

Abstract
The measurement of glycohemoglobin (GHb) by boronate affinity chromatography is useful in monitoring long-term glucose control in diabetic subjects. The inherent disadvantage of this method is the hands-on time required because the hemoglobin fractions are separated on individual disposable columns. To overcome this disadvantage, we have programmed a Hamilton Microlab 2200 automated pipetting cartesian robot to complete the procedure, from the aspiration of blood from the sample-collection tube to the transfer of the separated hemoglobin fractions to a microtiter plate for absorbance measurement. This automated robotic system can analyze 96 specimens, including patients' samples and control material, in approximately 3 h. The precision (CV) of the method ranged from 1.6% to 3.5% within-run and from 2.7% to 3.5% day-to-day. The results correlated with those obtained with the Accuflex semiautomated robot, which used the identical disposable column, and those obtained with a Primus high-performance liquid chromatograph, which used a regenerated microparticle column. Automation of the GHb procedure allowed improved throughput, reduced labor cost, improved precision, and offered greater laboratory safety.
C-reactive protein and its cytokine mediators in intensive-care patients
Authors: Sheldon J , Riches P , Gooding R , Soni N , Hobbs J R 
Published: January 2020

Abstract
C-reactive protein (CRP) is an acute-phase protein produced by the liver during bacterial infections and inflammation. The cytokines interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF) are widely reported to induce synthesis of CRP by hepatocytes both in vitro and in vivo. We investigated the relation between CRP and its cytokine mediators in 64 critically ill patients during their treatment in the intensive-care unit. Plasma CRP and IL-6 concentrations were significantly lower in patients without any evidence of infection than in those with clinical infection; plasma IL-1 beta concentrations showed no significant difference between any of the groups, but plasma TNF concentrations were lower in patients with evidence of infection. Significant correlation was seen between plasma concentrations of CRP and IL-6 when the latter was measured by bioassay; however, IL-6 showed, at best, only a 50% predictive value for a change in CRP concentration.
Early diagnosis of ectopic arginine vasopressin secretion
Authors: Coyle S , Penney M D , Masters P W , Walker B E 
Published: January 2020

Abstract
We describe a patient who presented with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) 2 months before clinical evidence of bronchogenic malignancy. Because of the potential for the ectopic production of atrial natriuretic peptide (ANP) to mimic SIADH, both hormones were measured in this hyponatremic patient to seek a possible marker of tumor activity. A hypertonic saline infusion at presentation revealed excessive osmotically decoupled secretion of arginine vasopressin but a normal ANP response.
Increase of plasma proapolipoprotein A-I in patients with liver cirrhosis and its relationship to circulating high-density lipoproteins 2 and 3
Authors: Suehiro T , Yamamoto M , Yoshida K , Ohno F 
Published: January 2020

Abstract
We determine the concentration of proapolipoprotein (proapo) A-I and its ratio with total apolipoprotein (apo) A-I (proapo A-I/total apo A-I) in plasma of patients with liver disease; we used a noncompetitive sandwich method, an enzyme-linked immunosorbent assay. The mean (SD) proapo A-I concentrations in patients with decompensated or compensated liver cirrhosis were higher than in normal subjects: 88 (25), 105 (36), and 69 (25) mg/L, respectively. The mean (SD) ratio (expressed as %) for each of these types of liver cirrhosis was also higher than in normal subjects: 10.0 (3.5), 10.2 (3.9), and 4.6 (1.6), respectively. In the patients, the proapo A-I concentration was positively correlated with the concentration of high-density lipoprotein subtype 2 cholesterol (HDL2-C) (r = 0.736), and the proapo A-I/total apo A-I ratio was correlated inversely with the HDL3-C concentration (r = -0.609). The activity of proapo A-I converting enzyme in patients with liver cirrhosis (62 +/- 30 nmol/h per liter) was significantly (P &lt; 0.01) lower than that in normal subjects (172 +/- 55 nmol/h per liter). The increases of the plasma proapo A-I concentration and ratio in patients with liver cirrhosis may be caused by a decreased production of the converting enzyme in the liver. The increase of plasma proapo A-I may thus also affect the circulating HDL subtypes.
Limitations of quality control in physicians' offices and other decentralized testing situations: the challenge to develop new methods of test validation
Authors: Baer D M , Belsey R E 
Published: January 2020

Abstract
Traditional quality-control methods are effective for detecting systematic error caused by deterioration of reagents or instruments, but ineffective for detecting sporadic error, which is more likely to occur in low-volume testing environments. Decentralized testing performed by individuals without formal laboratory training has a high potential for sporadic errors. New methods for validating test results, used each time a test result is produced, should replace current quality-control procedures. Under the rules of CLIA '88, manufacturers and the US Food and Drug Administration have an opportunity to develop new approaches to test validation.