bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fully enzymatic method for determining 1,5-anhydro-D-glucitol in serum
Authors: Fukumura Y , Tajima S , Oshitani S , Ushijima Y , Kobayashi I , Hara F , Yamamoto S , Yabuuchi M 
Published: January 2020

Abstract
We have developed a fully enzymatic method to measure 1,5 anhydro-D-glucitol (1,5-AG) in serum through use of pyranose oxidase (PROD: EC 1.1.3.10), glucokinase (EC 2.7.1.2), and an ATP-regenerating system. In a previous report (Clin Chem 1989;35:2039-43) the glucose interfering with the measurement of 1,5-AG was removed with a minicolumn. In the method used here, glucokinase and an ATP-regenerating system efficiently convert glucose to the unreactive compound, glucose 6-phosphate, making the method selective for 1,5-AG. The hydrogen peroxide produced in the oxidation of 1,5-AG by PROD is detected with a standard enzymatic color-developing system. The within-run and day-to-day precision (CV) of this method was 0.52-1.29% and 1.17-4.48%, respectively. The correlation (r) between the results obtained with our proposed method (y) and those obtained with the mini-column method (x) was 0.998 (y = 1.007x + 0.493 mg/L; n = 100; Sy/x = 0.641 mg/L). This newly developed method allows quicker and easier measurement of serum 1,5-AG than previously described methods.
Variance function as basis for assessment of test performance: methodological studies with two assays of prostate-specific antigen
Authors: Hänseler E , Keller B , Keller H 
Published: January 2020

Abstract
We evaluated the usefulness of a recently described procedure to assess the analytical performance of an assay. To demonstrate the advantages of this approach, we compared the performance of two analytical systems for determining prostate-specific antigen (PSA). Triplicate measurements of PSA with the IMx (Abbott) and the ACS 180 (Ciba Corning) were used to calculate the variance function. This function was the basis for the derivation of the critical limit (LC), the limit of detection (LD), the power of definition (PD), and the lower limit of the quantification interval. The standard deviation of the blank was extrapolated by means of the variance function. LC was calculated as the concentration at which the normal distribution of the blank intersects an adjacent normal distribution (with a defined overlap, e.g., 5%). The mean of the adjacent normal distribution represents the LD. The PD is a new mathematical approach to describe the analytical sensitivity of an assay in different ranges of the quantification interval. The procedure is statistically well defined and allows one to obtain the data on the test performance directly from patients' samples, without artificial zero controls. Therefore, use of the variance function could be a general model for the assessment of the analytical performance of an assay.
Is carbohydrate-deficient transferrin in serum useful for detecting excessive alcohol consumption in hypertensive patients?
Authors: Fagerberg B , Agewall S , Berglund A , Wysocki M , Lundberg P A , Lindstedt G 
Published: January 2020

Abstract
The aim of this study was to examine the diagnostic usefulness of carbohydrate-deficient transferrin (CDT) in serum in a cross-sectional study of 439 treated hypertensive men. We related the results to alcohol intake by questionnaire and to biochemical and hemodynamic measurements known to reflect excessive alcohol consumption. The diagnostic sensitivity and the specificity for high alcohol intake (&gt; or = 24 g/day of ethanol) were 44% and 87%, respectively. The group with reported high alcohol intake (n = 32) was characterized by hemodynamic and biochemical changes typical of alcohol abuse. The corresponding profile for the patients with increased serum CDT concentrations (n = 70) was different in several respects, indicating a considerable number of false-positive tests. We conclude that serum CDT determination had low sensitivity and specificity for excessive alcohol consumption in this group of hypertensive patients. The results illustrate the importance of evaluating new laboratory methods in unselected patient populations before drawing any conclusions about their clinical value.
Creatine kinase isoenzyme BB increased in serum and tumor tissue of patients with giant cell tumor of bone
Authors: Fukuda J , Yagishita S , Yamaoka K , Hanihara T , Kushida K , Murayama H 
Published: January 2020

Abstract
Increased creatine kinase isoenzyme BB (CK-BB) has been observed in sera from patients with brain injuries and occasionally in sera from patients with malignancy. We report here that, in two patients with giant cell tumor of bone (GCT), preoperative serum CK-BB increased to approximately 20 and 90 U/L, but in postoperative serum the CK-BB decreased to normal values. That the tumors contained CK-BB was indicated by electrophoretic analysis and immunohistochemical staining. Furthermore, serum CK-BB was detectable in five additional cases of GCT and in cultured tumor cells from a patient with GCT by an electrophoretic method. These results suggest that CK-BB may be a marker for GCT.
Use of cardiac troponin I to diagnose perioperative myocardial infarction in coronary artery bypass grafting
Authors: Mair J , Larue C , Mair P , Balogh D , Calzolari C , Puschendorf B 
Published: January 2020

Abstract
Cardiac troponin I (cTnI) is a regulatory protein unique to myocardium. We used a cardiospecific 30-min ELISA to measure cTnI in EDTA-plasma samples serially drawn from 28 patients before and after coronary artery bypass grafting (CABG)--26 elective and 2 salvage cases. The cTnI increase in 22 of the elective CABG patients, who did not have perioperative myocardial infarction (not-PMI), reflected the inevitable myocardial damage caused by cannulation and cardioplegic arrest, with peak values of 1.7 +/- 1.0 microgram/L (mean + 2 SD = 3.7 micrograms/L), the peaks occurring on average 8 h (range 4-24) after aortic unclamping. Two of the 22 not-PMI, elective CABG patients showed cTnI peaks &gt; 3.0 micrograms/L (3.9 and 3.4 micrograms/L), indicating more extensive perioperative myocardial damage than the other 20, as confirmed by clinical and electrocardiographic or echocardiographic signs, although creatine kinase isoenzyme MB (CKMB) activity was below our PMI decision limit of 20 U/L (25 degrees C). As classified by electrocardiography, echocardiography, and increased CKMB activity, four of the 26 elective CABG patients did have a PMI. One patient with Q-wave PMI had peak cTnI approximately 30 micrograms/L, and three with non-Q-wave PMI had lower peak values (approximately 5 micrograms/L). The two salvage CABG cases had increased cTnI before surgery. One developed a Q-wave acute myocardial infarction with a 3-h cTnI peak of approximately 35 micrograms/L. We conclude that, after elective CABG, cTnI peaks &gt; 3.7 micrograms/L and concentrations &gt; 3.1 micrograms/L at 12 h or 2.5 micrograms/L at 24 h indicate PMI with high probability.
Hormone conference at Sahlgren's University Hospital: polycythemia and inappropriately high serum erythropoietin concentration in a 62-year-old man
Authors: Lindstedt G , Lundberg P A , Norrby A , Kutti J , Andersen O , Jakobsson K E , Nordborg C , Bengtsson B A 
Published: January 2020

Abstract
A 62-year-old man with a history of coronary insufficiency complained at his scheduled visit to the outpatient clinic of symptoms suggestive of gastritis. His blood hemoglobin concentration, however, was markedly increased. Results of a hematological work-up suggested an erythropoietin-producing tumor. Signs of increased intracranial pressure then led to the finding of a cerebellar tumor, which could explain his vertigo and abdominal symptoms. This cystic capillary hemangioblastoma probably was responsible for the erythropoietin production and also seemed to produce basic fibroblast growth factor. The clinical evaluation of polycythemia as well as erythropoietin biochemistry and clinical application are reviewed.
Autoimmune endocrinopathies: aspects of pathogenesis and the role of immune assays in investigation and management
Authors: Volpé R 
Published: January 2020

Abstract
It has been hypothesized over many years that the autoimmune endocrine diseases are each due to antigen-specific defects in suppressor (regulatory) T lymphocyte function. There is now increasing evidence in studies of autoimmune thyroid disease and insulin-dependent diabetes mellitus that suppressor cells are activated by irrelevant antigens but respond inadequately to specific relevant antigens. These inadequate responses are insufficient in themselves to precipitate the autoimmune disease; further insults from the environment increase the deficiencies in regulatory cell activity, adding to the genetically induced dysfunction, i.e., specific defects in antigen presentation. Diagnostic procedures for autoimmune endocrine diseases include tests of target cell function and the detection of various antibodies, which are becoming increasingly useful in prediction, diagnosis, and management of these diseases.
Laboratory diagnosis and monitoring in chronic systemic autoimmune diseases
Authors: Osterland C K 
Published: January 2020

Abstract
The testing done in the diagnostic immunology laboratory contributes to the management of patients with systemic autoimmune diseases. In these diseases the interaction between environmental factors and a genetically dysregulated immune system produces a continually variable level of disease activity. Improved techniques now allow the clinical scientist to assess the integrity of a patient's immune system and to ascertain qualitative or quantitative disturbances in its activation and expression. Cellular and humoral immunity may become independently activated or dysfunctional in certain disease processes, although the generation of amplifying proteins may result in the full clinical expression of immunity and autoimmune inflammation. Autoimmune diseases can, in part, be characterized according to the activation pattern of gene expression encoding the amplifying and proinflammatory cytokines. Modern therapy is increasingly aimed at determining ways to influence discrete elements of the immune apparatus; therefore, it is important to identify and characterize the patterns of expression of the immune system mediators serially in chronic autoimmune disease states. Newer diagnostic procedures stemming from observations in basic and clinical research are expanding the useful database on patients, but they must be carefully evaluated to prove their applicability and efficacy. Because blood samples are the best available specimens for testing, one must consider all the possible sampling problems and pitfalls of using results from peripheral blood to judge changes in function of the lymphoid system.
The monoclonal gammopathies
Authors: Kyle R A 
Published: January 2020

Abstract
Each monoclonal protein (M-protein, or myeloma protein) consists of two heavy polypeptide chains of the same class and subclass and two light polypeptide chains of the same type. Electrophoresis on cellulose acetate membranes is satisfactory for screening, although agarose electrophoresis is more sensitive for detecting small M-proteins. Immunoelectrophoresis should be performed when myeloma, macroglobulinemia, amyloidosis, or a related disorder is suspected. Immunofixation is useful when results of immunoelectrophoresis are equivocal. The recognition of a Bence Jones protein depends on the demonstration of a monoclonal light chain by immunoelectrophoresis or immunofixation of an adequately concentrated urine specimen. The differential diagnosis of an M-protein includes monoclonal gammopathy of undetermined significance (benign monoclonal gammopathy), multiple myeloma, solitary plasmacytoma of bone or extramedullary plasmacytoma, macroglobulinemia, lymphoma, chronic lymphocytic leukemia, and primary systemic amyloidosis.
Metabolic determinants of the course of coronary artery disease in men
Authors: Watts G F , Mandalia S , Slavin B M , Brunt J N , Coltart D J , Lewis B 
Published: January 2020

Abstract
We examined associations between metabolic variables and changes in coronary artery disease (CAD) in the St. Thomas' Atherosclerosis Regression Study (STARS). The course of CAD over 3 years was measured continually by quantitative coronary angiography, i.e., as the per patient change in the mean absolute width of coronary segments (delta MAWS). The decrease in MAWS (progression of CAD) was significantly correlated with in-trial plasma concentrations of cholesterol (P = 0.002), low-density lipoprotein (LDL) cholesterol (P = 0.001), apolipoprotein B (apoB) (P = 0.008), and lipoprotein(a) [Lp(a)] (P = 0.004); no significant associations were found with high-density lipoprotein (HDL) cholesterol, apoA-I, vitamin E, thyroid hormones, fibrinogen, von Willebrand factor, or post-load plasma glucose and insulin concentrations. By multiple regression analysis, LDL cholesterol was the best predictor of delta MAWS, the adjusted model explaining 22% of the variance (P = 0.04). Thus, in men with symptomatic CAD the most important metabolic predictor of change in CAD is plasma LDL cholesterol, there being no advantage in measuring other variables, in particular, apoB or Lp(a).
Quantification of hemoglobin variants by capillary isoelectric focusing
Authors: Hempe J M , Craver R D 
Published: January 2020

Abstract
Capillary isoelectric focusing (cIEF) was used to identify and quantify major and minor hemoglobin (Hb) variants. Whole blood (approximately 10 microL required) hemolysate was analyzed with a commercial instrument equipped with a 50 microns (i.d.) x 27 cm coated capillary filled with 20 g/L ampholytes (pH 6-8) in 4 g/L methylcellulose (MC). Cathode and anode solutions were 20 mol/L NaOH and 100 mol/L H3PO4 in MC, respectively. Samples (approximately 40 nL) were applied via autosampler by low-pressure injection, focused for 3 min at 30 kV, and mobilized by simultaneous voltage and low pressure past the detector, where absorbance at 415 nm was analyzed by an automated data acquisition system. Blood from subjects with sickle cell trait, Hb S/C disease, and various beta-thalassemias were analyzed by cIEF in &lt; 15 min. cIEF was used to separate Hb S from Hb D-Los Angeles. Assay precision determined with commercial controls gave CV &lt; 2% for Hb A and S, and 1-11% for minor Hb variants A2, F, and A1c. Results obtained by cIEF for patients' samples agreed well with values determined by conventional assays (r2 &gt; 0.95). The results demonstrate that cIEF is a rapid, sensitive, high-resolution automated method for routine quantitative clinical analysis of Hb variants.
Is determination of creatine kinase-2 after electrophoretic separation accurate?
Authors: Henderson A R , Stark J A , McQueen M J , Patten R L , Krishnan S , Wood D E , Webb S 
Published: January 2020

Abstract
Since 1991, the Ontario Laboratory Proficiency Testing Program has assessed the analytical performance of creatine kinase (CK; EC 2.7.3.2) isoenzyme-2, using fresh human serum supplemented with purified human CK isoenzymes. In Ontario, the 142 laboratories licensed to analyze CK-2 use a variety of methods: electrophoresis-based, immunoinhibition, and mass assays. During a 1992 survey, duplicate CK-2 samples with different total CK activities showed poorer precision when analyzed after electrophoretic separation than by any other method. A 1993 survey designed to validate these observations conclusively showed that electrophoresis-based assays are subject to a bias proportional to the total CK activity. These survey results were confirmed by studies with selected patients' specimens. We therefore conclude that electrophoresis-based assays may not warrant their reputation as the gold standard for CK isoenzyme measurement.
Characterization of drug interferences caused by coelution of substances in gas chromatography/mass spectrometry confirmation of targeted drugs in full-scan and selected-ion monitoring modes
Authors: Wu A H , Ostheimer D , Cremese M , Forte E , Hill D 
Published: January 2020

Abstract
Interference by substances coeluting with targeted drugs is a general problem for gas chromatographic/mass spectrometric analysis of urine. To characterize these interferences, we examined human urine samples containing benzoylecgonine and fluconazole, and other drug combinations including deuterated internal standards that coelute (ISd,c) with target drugs, by selected-ion monitoring (SIM) and full-scan mass spectrometry. We show that, by SIM analysis, detecting the presence of an interferent is dependent on the specific IS used for the assay. When an ISd,c is used, the presence of another coeluting substance (interferent) suggests that the intensity of IS ions is substantially diminished, because the interferent affects both the ISd,c and target drug. When a noncoeluting IS (ISnc) is used, the interferent cannot be discerned unless it coincidently contains one or more of the ions monitored for either the target drug or ISnc. Under full-scan analysis, a coeluting interferent is directly discernable by examining the total ion gas chromatogram.
One-hour test for estimating intestinal absorption of calcium by using stable strontium as a marker
Authors: Sips A J , Netelenbos J C , Barto R , Lips P , van der Vijgh W J 
Published: January 2020

Abstract
Intestinal absorption of calcium is a relevant marker in a broad spectrum of diseases; however, its determination in clinical practice is difficult. Our aim was to design a simple test for this based on stable strontium (88Sr). The correlation between the intestinal absorption of simultaneously administered 45Ca and 88Sr was investigated in patients with various disorders of the bone and calcium metabolism. The area under the curve for the period 0-60 min after dosing (AUC0-60 in mmol.L-1.min), being a representative measure of intestinal absorption, showed a close correlation between both elements (r = 0.90, P &lt; 0.001). Moreover, the measure of agreement in classifying the patients as low, intermediate, or high absorbers was high (kappa = 0.80). We conclude that a test based on measuring AUC0-60 of strontium is a fast and inexpensive way to obtain reliable information about the level of intestinal calcium absorption.
Overview of mood disorders: diagnosis, classification, and management
Authors: Fawcett J 
Published: January 2020

Abstract
This discussion of the diagnosis, classification, and epidemiology of clinical depression includes details of the associated physical morbidity, mortality, and impairment. Treatment approaches to depressive disorders are categorized with an emphasis on medication management, including improved treatment efficacy and progress with respect to side effects and toxicity. Although considerable advances have been made, with 18 antidepressant compounds being available and the impending release of two new antidepressant compounds in 1994, no one agent has demonstrated greater efficacy than another. Currently available studies suggest that only 21-42% of patients entered into treatment reach full recovery, while 20% of patients do not respond to available treatment but remain chronically depressed. Thus, the development of more efficacious agents that will produce complete remissions in patients who now achieve only partial treatment responses is a major challenge for biochemical, pharmacological, and clinical research of the treatment of mood disorders.
Lithium and the brain: a psychopharmacological strategy to a molecular basis for manic depressive illness
Authors: Lenox R H , Watson D G 
Published: January 2020

Abstract
Lithium, an effective treatment for mania and the prevention of recurrent episodes of both mania and depression in patients with manic depressive illness, exerts multiple biochemical effects. However, any clinically relevant site of action of lithium must occur at therapeutic concentrations attained in the brain of patients and must account for the lag period accompanying onset of action as well as effects persisting beyond discontinuation of treatment. This monovalent cation acts as a potent uncompetitive inhibitor in the receptor-coupled breakdown of inositol phospholipids, resulting in a relative depletion of inositol and an alteration in the generation of diacylglycerol, an endogenous activator of protein kinase C. In our laboratory, we are examining the action of chronically administered lithium on posttranslational modification of specific phosphoproteins involved in regulating signal transduction in the brain. We have found that chronic, but not acute, administration of lithium in rats markedly reduces a major phosphoprotein substrate of protein kinase C in the hippocampus, an effect that persists beyond the cessation of lithium treatment. This protein, myristoylated alanine-rich C kinase substrate ("MARCKS"), is implicated in synaptic neurotransmission, calcium regulation, and cytoskeletal restructuring. These findings have relevance for the long-term action of lithium in stabilizing an underlying dysregulation in the brain and may move us closer to formulating a molecular basis of manic depressive illness.
Two methods for measuring carbohydrate-deficient transferrin in inpatient alcoholics and healthy controls compared
Authors: Anton R , Bean P 
Published: January 2020

Abstract
Carbohydrate-deficient transferrins (CDTs), naturally occurring glycosylated transferrin proteins, are reported to be increased in the serum of individuals who consume large quantities of alcohol (ethanol). We compared two methods for the separation and quantification of CDT, using the same alcohol-dependent patients and age-, gender-, and race-matched controls as sources of samples for both assays. There was good correlation (r = 0.89) between the microcolumn anion-exchange chromatography/RIA (MAEC/RIA) procedure and the isoelectric focusing, immunoblotting, and laser densitometry (IEF/IB/LD) procedure. Receiver operating characteristic analysis suggested that the IEF/IB/LD procedure would perform slightly better than MAEC/RIA for the overall population. However, both assays were much more sensitive for the detection of heavy alcohol consumption in men, compared with women. Alcohol consumption in the week prior to CDT measurement correlated only weakly with the concentrations measured with either assay.
Nonlinearity of high-density lipoprotein cholesterol determinations is matrix dependent
Authors: Kroll M H , Chesler R 
Published: January 2020

Abstract
The majority of methods for determining high-density lipoprotein (HDL) cholesterol failed the 1991 College of American Pathologists (CAP) linearity survey (sets LN2-A, B, C). We hypothesized that they failed because of the survey material matrix. We evaluated linearity with dextran sulfate or phosphotungstate as the precipitating reagents for several methods: Ektachem; TDx; Sigma; Dimension; Cobas Fara, with Roche reagents; and the Hitachi 736, with precipitating reagents from Boehringer Mannheim Diagnostics. We tested CAP survey material, Sigma HDL-cholesterol control material, and a fresh serum pool for linearity, using the polynomial method. All of the methods were nonlinear for the CAP material and for the controls precipitated after dilution. Five of eight methods were linear for the control materials precipitated before dilution. All methods but one were linear for the serum pool. These results demonstrate that the source of the nonlinearity is located in the precipitation step and depends on the sample matrix.