bluuebunny/crossref_metadata_2025_split huggingface dataset:
D-Mannose as a Preservative of Glucose in Blood Samples
Authors: Chan A Y , Ho C S , Chan T Y , Swaminathan R 
Published: January 2020

Abstract
We studied the changes in blood glucose concentration in blood samples collected in heparinized specimen tubes containing no other preservative, or containing NaF, D-mannose, or a combination of NaF and D-mannose. Blood concentration in samples taken into NaF decreased by 0.40 mmol/L in the first 2 h; thereafter, there was no change. In samples collected into mannose there was a small but significant decrease in blood glucose concentration with time. When samples containing mannose were analyzed immediately after collection, the concentration of glucose was higher than in later analyses, probably because of an exchange of intracellular glucose for extracellular mannose. When a combination of NaF and mannose was used, the blood glucose concentration was relatively stable but slightly higher than nonpreserved samples for the next 24 h. However, samples containing mannose were unsuitable for electrolyte analysis. We conclude that a combination of D-mannose and NaF may be a better preservative for blood glucose than either compound alone.
Free Triiodothyronine in Sera of Acutely Ill General Medical Patients: a Prognostic Indicator
Authors: Mak Y T , Chan E L , Chan A , Woo J , Swaminathan R 
Published: January 2020

Abstract
We measured free triiodothyronine (FT3), thyrotropin (TSH), and C-reactive protein (CRP) in sera of 39 acutely ill medical patients who died within three months of admission and 39 age- and sex-matched control patients selected at random from a total of 294 acute medical admissions. Serum FT3 in nonsurvivors (1.91 +/- 1.51 pmol/L) was significantly lower than that in survivors (3.01 +/- 1.3 pmol/L, P less than 0.01) and the CRP in nonsurvivors (54.6 +/- 59.2 mg/L) was significantly higher than in survivors (43.6 +/- 59.5 mg/L, P less than 0.05). There was no difference in plasma TSH between the two groups. The estimated odds ratio relating death to a plasma FT3 value less than 1.0 pmol/L on admission was 17 (highly significant: P less than 0.001). We conclude that plasma FT3 may be a useful prognostic indicator in acutely ill patients.
Biochemical Diagnosis of Pheochromocytoma by Simultaneous Measurement of Urinary Excretion of Epinephrine and Norepinephrine
Authors: Smythe G A , Edwards G , Graham P , Lazarus L 
Published: January 2020

Abstract
The utility of specific assay of urinary catechols in pheochromocytoma diagnosis was examined by reviewing our data on the investigation of pheochromocytoma in a population of 2476 patients investigated over a six-year period. We used specific gas-chromatographic/mass-spectrometric (GC/MS) analysis for the simultaneous measurement of norepinephrine, dopamine, and the neuronal metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3,4-dihydroxyphenylacetic acid (DOPAC) in all samples; the last two years of data collection (from 1101 patients) also included the specific GC/MS assay of epinephrine. The importance of assaying epinephrine as well as norepinephrine was shown by these latter data. During this latter period, 19 of 1101 patients were found to have pheochromocytoma; of these, nine had tumors that exclusively secreted norepinephrine, six had tumors that exclusively secreted epinephrine, and four exhibited excess production of both norepinephrine and epinephrine. Neither dopamine nor DOPAC was useful in the diagnosis of pheochromocytoma. A substantial proportion of patients may have uniquely epinephrine-secreting pheochromocytomas, previously considered a rarity. Thus we recommend that the biochemical testing for pheochromocytoma include the specific measurement of both norepinephrine and epinephrine.
Improved Diagnosis of Carcinoid Tumors by Measurement of Platelet Serotonin
Authors: Kema I P , de Vries E G , Schellings A M , Postmus P E , Muskiet F A 
Published: January 2020

Abstract
Carcinoid patients are diagnosed biochemically on the basis of increased urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA); urinary and platelet serotonin concentrations are considered to provide complementary information. Using established HPLC methods with fluorometric detection, we evaluated the clinical usefulness of measurements of urinary 5-HIAA and urinary, plasma, and platelet serotonin in 30 consecutive patients with histologically proven carcinoid tumors of fore-, mid-, and hindgut origin before treatment. Ten patients showed no signs of serotonin overproduction; 14 had increased concentrations of urinary 5-HIAA and platelet serotonin; and platelet serotonin, but not urinary 5-HIAA, was increased in 6. None had increased urinary 5-HIAA excretion without an increase in platelet serotonin content. In cases with high rates of tumor serotonin secretion, platelet serotonin reached a maximum and did not correlate with serotonin secretion rate, whereas urinary 5-HIAA was correlated. Increased platelet serotonin was correlated with increased plasma serotonin and with occurrence of carcinoid syndrome. Increased urinary serotonin, allegedly caused by increases in circulating 5-hydroxytryptophan, almost invariably coincided with increased platelet serotonin, but not necessarily with above-normal urinary 5-HIAA excretion. From these results and long-term monitoring of three patients during treatment, we conclude that platelet serotonin is more sensitive than urinary 5-HIAA for detecting carcinoids that secrete only small amounts of serotonin.
Ultrasensitive Thyrotropin Immunoassay Based on Enzymatically Amplified Time-Resolved Fluorescence with a Terbium Chelate
Authors: Papanastasiou-Diamandi A , Christopoulos T K , Diamandis E P 
Published: January 2020

Abstract
We describe an ultrasensitive, enzymatically amplified time-resolved fluorescence immunoassay of thyrotropin (thyroid-stimulating hormone) in serum with use of a terbium chelate as the detectable moiety. In this assay, thyrotropin is first simultaneously reacted with a solid-phase (microtiter well) monoclonal antibody and a soluble biotinylated monoclonal detection antibody. After washing, a streptavidin-alkaline phosphatase conjugate is added, followed by another washing. Alkaline phosphatase acts on the substrate 5-fluorosalicyl phosphate (FSAP) to produce 5-fluorosalicylic acid (FSA). FSA, but not FSAP, can then form with Tb3+ and EDTA a highly fluorescent ternary complex of long fluorescence lifetime. This complex is quantified with time-resolved fluorometry. The thyrotropin assay is highly sensitive (detection limit approximately 0.003 milli-int. unit/L when a total assay time of 85 min is used), precise, and accurate. The thyrotropin assay can also be completed in less than 30 min (detection limit 0.013 milli-int. unit/L), thus making this procedure a candidate technology for high-throughput automated analyzers.
Effect of in Vitro Hemolysis on 25 Common Biochemical Tests
Authors: Yücel D , Dalva K 
Published: January 2020

Abstract
Clinical chemists frequently encounter hemolyzed samples. Our study examines the effects of hemolysis on the results of 25 common biochemical tests. We collected 60 15-mL blood samples from inpatients and outpatients and mechanically hemolyzed 10 mL of the samples in a two-step procedure. We classified serum from these samples as being nonhemolyzed, moderately hemolyzed, or severely hemolyzed and then performed 25 common biochemical tests. Statistical analysis of the results showed that hemolysis had the greatest effect on the lactate dehydrogenase, acid phosphatase, and potassium tests.
Wheat-Germ Lectin Affinity Electrophoresis for Alkaline Phosphatase Isoforms in Children: Age-Dependent Reference Ranges and Changes in Liver and Bone Disease
Authors: Crofton P M 
Published: January 2020

Abstract
This modified lectin affinity electrophoresis method is suitable for simultaneous measurement of liver, bone, and high-molecular-mass (high-Mr) isoforms of alkaline phosphatase (ALP; EC 3.1.3.1) in children. Age-related isoform reference ranges were derived for 247 children, ages 0-13 years. Liver ALP did not appear in plasma until after six months of age, and remained constant after one year of age. Bone ALP was highest in the youngest age group, and declined to relatively constant activities thereafter. High-MrALP was not detected in normal children. In bone disease, the bone isoform was increased in all age groups. In liver disease, only 5 of 30 infants younger than six months had detectable liver ALP, although half had increased bone ALP. Among children older than six months, 5 patients with biliary atresia and 15 patients with hepatitis A all had increased liver isoform activity. Liver ALP was also a sensitive index of early hepatobiliary complications in 27 nonjaundiced children with cystic fibrosis. Measurement of ALP isoforms therefore yields useful clinical information in children older than six months but is of doubtful value in younger infants.
Malondialdehyde Kit Evaluated for Determining Plasma and Lipoprotein Fractions that React with Thiobarbituric Acid
Authors: Richard M J , Portal B , Meo J , Coudray C , Hadjian A , Favier A 
Published: January 2020

Abstract
The determination of thiobarbituric acid reactants (TBARs) is a widely used method for investigating overall lipid peroxidation. An assay kit that could be used with plasma and lipid fractions would facilitate standardization of the method. The results reported here indicate that the malondialdehyde (MDA) kit manufactured by Sobioda (Grenoble, France) complies with criteria of good analytical practices. The detection limit was 0.11 mumol of MDA per liter of plasma. The within-run (CV = 1.8-3.3%) and between-run (CV = 3.3-4.4%) precisions were acceptable. The analytical recovery of MDA after supplementing human plasma samples with tetraethoxypropane standards varied from 88% to 100%. The mean (SD) lipoperoxide concentration determined in 32 healthy adults, ages 20-40 years, was 2.51 (0.25) mumol/L. No significant sex-related difference was noted: 2.57 (0.28) in men vs 2.44 (0.20) mumol/L in women. Applying the method to lipid fractions showed that lipoprotein fractions contain relatively little MDA: 0.07 (0.03) mumol/L of plasma for very-low-density lipoproteins and 0.19 (0.10) mumol/L for low-density lipoproteins.
Direct Time-Resolved Fluorescence Immunoassay of Progesterone in Serum Involving the Biotin-Streptavidin System and the Immobilized-Antibody Approach
Authors: Kakabakos S E , Khosravi M J 
Published: January 2020

Abstract
We developed a direct competitive-type immunoassay for progesterone in serum that combines the advantages of the biotin-streptavidin system with the antibody-immunobilization approach. We synthesized biotinylated progesterone derivatives of five different proteins and, after initial evaluation of the conjugates, selected biotinylated bovine IgG-progesterone as the most suitable tracer. Progesterone released from binding proteins with danazol competes with the biotinylated tracer conjugate for binding to a limited amount of a mouse anti-progesterone monoclonal antibody in microtitration wells coated with a goat anti-mouse IgG antibody. The binding of the biotinylated tracer is then monitored by reaction with a streptavidin-based universal detection reagent developed for time-resolved fluorometry. The assay demonstrated typical performance characteristics with respect to the dynamic range, detection limit, and precision. Recovery averaged 99.3% (SD 8.3%) and dilution experiments showed good linearity. Measurements correlated well with those from three commercially available direct immunoassays for progesterone.
Special Collection and Storage Tubes for Blood Endotoxin and Cytokine Measurements
Authors: Redl H , Bahrami S , Leichtfried G , Schlag G 
Published: January 2020

Abstract
Commercially available blood-collection tubes may be contaminated with endotoxin (315 +/- 95 pg/tube) and could therefore be unsuitable for blood collection for endotoxin measurement. Plasma separation and storage are a potential source of contamination. To avoid contamination and error, we have developed new blood collection tubes that contain heparin free of endotoxin (LPS) and a gel to separate plasma and blood cells. The LPS content is less than 4 pg/tube. Samples can be stored and frozen without plasma withdrawal to preclude contamination. LPS recovery experiments have shown that the new blood-collection tubes do not bind LPS to the separation gel or vial wall. With these tubes, in vitro formation of tumor necrosis factor (404 +/- 163 ng/L in standard tubes vs less than 40 ng/L in special collection tubes) is minimized.
Laboratory Values in Fit Aging Individuals--Sexagenarians through Centenarians
Authors: Tietz N W , Shuey D F , Wekstein D R 
Published: January 2020

Abstract
We determined approximately 15,000 laboratory values in 236 individuals between the ages of 60 and 90 y, 22 individuals between 90 and 99 y, and 69 individuals greater than or equal to 100 y, and compared these with values in young adults. We tested 47 different analytes in the 60-90-y group and 93 analytes in the greater than or equal to 90-y group. Na, K, Cl, and CO2 values were either identical or showed minimal change with age; pH decreased slightly. Differences in Ca values were only minor, but ionized Ca increased slightly. Phosphate decreased in men, but changed only minimally in women; parathyroid hormone increased with age. Increases with age were also observed for glucose, insulin, and C-peptide. Among the enzymes, alkaline phosphatase increased in women, but in men only greater than 90 y; gamma-glutamyltransferase increased in both sexes. Creatine kinase (CK) decreased slightly in individuals greater than 70 y and markedly in those greater than 90 y of age, whereas CK-MB decreased markedly greater than 70 y, reaching the detection limit in individuals greater than 90 y. Lactate dehydrogenase isoenzyme 5 decreased slightly with age. Urea nitrogen increased gradually with age, but creatinine increased only in individuals greater than or equal to 90 y. The increase in urea is not paralleled by a loss of protein in urine, suggesting that the possible cause of azotemia may not always be renal pathology. Urate increased in women but not in men. Liver function, as measured by total bilirubin and liver enzymes, was exceedingly well maintained. Concentrations of most proteins show little change, except for slight decreases in prealbumin, albumin, and transferrin, proteins used as an index of nutritional status. IgA values increased, IgG ranges were wider, IgM and IgD decreased, and the range for IgE was narrower than in young adults. Cholesterol, high-density lipoprotein cholesterol, and triglyceride values increased with age, but decreased in individuals greater than or equal to 90 y. Among the trace elements, magnesium changed little, zinc and lead decreased, and copper values increased with age. Total triiodothyronine and thyroxine decreased, with concomitant increases in thyroid-stimulating hormone. More individuals had increased microsomal antibodies and thyroglobulin titers in the aging population than in the young. In men, the free, percent free, bioactive, and total testosterone values decreased, but luteinizing hormone (LH) and follicle-stimulating hormone (FSH) values increased. In women, estrone and estradiol values decreased, with concomitant increases in LH and FSH. Androstenedione and progesterone decreased in both sexes.(ABSTRACT TRUNCATED AT 400 WORDS)
Age-Related Changes of Neuron-Specific Enolase, S-100 Protein, and Myelin Basic Protein Concentrations in Cerebrospinal Fluid
Authors: van Engelen B G , Lamers K J , Gabreels F J , Wevers R A , van Geel W J , Borm G F 
Published: January 2020

Abstract
Studies on cerebrospinal fluid (CSF) concentrations of neuron-specific enolase (NSE), S-100 protein, and myelin basic protein (MBP) in patients with neurological lesions indicate a quantitative relation between the degree of cell damage in the central nervous system (CNS) and the concentration of these CNS-specific proteins in CSF. Thus NSE, S-100, and MBP could be of use as markers for destructive processes in the CNS. We collected 937 specimens of CSF from children and adults (from newborns to age 91 years) who were undergoing a diagnostic lumbar puncture for several clinical indications. Of these, 79 samples from subjects ranging in age from 0.7 to 66 years could be used retrospectively to construct a reference interval according to our criteria. In these 79 samples no sex dependency existed. The relative increase of NSE, S-100, and MBP with age was similar (1% per year), suggesting a common underlying mechanism. These results emphasize the necessity of using age-matched reference values when the CNS-specific proteins are to be evaluated in neurological diseases. We also present three case histories to discuss the possible clinical relevance of the measurement of NSE, S-100, and MBP in children and adults.
Concentration Dependencies of Immunoturbidimetric Dose-Response Curves: Immunoturbidimetric Titer and Reactivity, and Relevance to Design of Turbidimetric Immunoassays
Authors: Shahangian S , Agee K A , Dickinson R P 
Published: January 2020

Abstract
To characterize polyclonal antisera for two-point immunoturbidimetric applications, we defined, as functions of antiserum concentration, two parameters derived from dose-response curves: the maximum bichromatic optical response, Tmax, and the antigen concentration in the region of excess antibody corresponding to one-half Tmax, or C50. We raised monospecific polyclonal antisera in goats against several human immunoglobulins, C-reactive protein, C3, C4, apolipoproteins A-I and B, and several other proteins. We could linearly relate the logarithm of the antiserum concentration to log C50 and to log Tmax. The concentration of polyethylene glycol affected not only C50 and Tmax but also their functional dependencies on antiserum concentration. We devised two definitions of immunoturbidimetric titer and related them to the titer obtained by the single radial immunodiffusion method of Becker (Immunochemistry 1969; 6:539-46).
Single Stable Reagent (Arsenazo III) for Optically Robust Measurement of Calcium in Serum and Plasma
Authors: Leary N O , Pembroke A , Duggan P F 
Published: January 2020

Abstract
We describe a method based on a single stable reagent for the determination of calcium in serum and plasma with use of Arsenazo III, 200 mumol/L in 50 mmol/L 1,4-piperazinediethanesulfonic acid (PIPES) buffer. The method showed significant positive interference in plasma at pH less than 6.6 because of the precipitation of fibrinogen, which was eliminated by increasing the pH to 6.8. The assay showed no interference from as much as 600 mumol of bilirubin and 12 g of hemoglobin per liter when applied in a simple monochromatic procedure at 660 nm. The standard curve for calcium was linear from 0 to 5.0 mmol/L. Addition of Intralipid at concentrations greater than 3 g/L demonstrated positive interference, which could be eliminated by using a 700-nm blanking wavelength. The procedure showed good agreement with all-method mean values from two external quality-control schemes.
Radioreceptor Assay for Quantifying FK-506 Immunosuppressant in Whole Blood
Authors: Murthy J N , Chen Y , Warty V S , Venkataramanan R , Donnelly J G , Zeevi A , Soldin S J 
Published: January 2020

Abstract
We describe a quantitative radioreceptor assay (RRA) for quantifying FK-506 in whole blood. FK-506 extracted from whole blood with a cyclohexyl-sorbent column competes with [3H]dihydro-FK-506 for binding to a partially purified preparation of FK-506 binding protein (FK-BP). Free and protein-bound FK-506 are separated on LH 20 Sephadex chromatographic columns. We compared the results of this method with those of an enzyme immunoassay that uses a monoclonal antibody: r = 0.97, Sy/x = 0.039. Between-day precisions (CV) at FK-506 concentrations of 8 and 17 micrograms/L were 9.2% and 8.2%, respectively. Within-run precisions were 5.9%, 8.1%, and 9.4%, respectively, at 4, 8, and 15 micrograms/L. Analytical recovery, evaluated at 5, 10, 15, 20, and 25 micrograms/L for FK-506 added to whole blood, ranged from 98% to 103%. The assay can reliably quantify FK-506 blood concentrations between 1.0 and 25 micrograms/L.
Serum Adenosine Deaminase: Isoenzymes and Diagnostic Application
Authors: Ungerer J P , Oosthuizen H M , Bissbort S H , Vermaak W J 
Published: January 2020

Abstract
Human adenosine deaminase (ADA; EC 3.5.4.4) consists of three isoenzymes: ADA1, ADA1+CP, and ADA2. We developed an electrophoretic technique to distinguish between these three isoenzymes. The isoenzyme pattern was studied in tissue and cell homogenates, as well as in serum from normal subjects and from patients with increased serum ADA who had either hepatitis, infectious mononucleosis, tuberculosis, pneumonia, rheumatoid arthritis, or acute lymphoblastic leukemia (ALL). The highest ADA activity was found in lymphocytes and monocytes. ADA2 could be detected only in monocytes (18% of total ADA activity). It was also the predominant isoenzyme in the sera of controls and all disease groups, except for ALL--the only condition evaluated that is not of an inflammatory nature. We conclude that serum ADA reflects monocyte/macrophage activity or turnover in most diseases studied. The exception is ALL, where serum ADA most probably originates from lymphocyte precursors.
Measuring Albumin and Calcium in Serum in a Dual Test with the Hitachi 704
Authors: Leary N O , Pembroke A , Duggan P F 
Published: January 2020

Abstract
We describe a method for simultaneously determining albumin, by using bromcresol purple, and calcium, by using Arsenazo III, in the same analytical cuvette on the Hitachi 704. Both assays agree well with accepted procedures. The standard curves for the albumin and calcium assays are linear from 0 to 60 g/L and 0 to 5.0 mmol/L, respectively. Calibration is stable for 7 days with use of open reagent in the instrument. Both assays are unaffected by hemoglobin less than or equal to 5 g/L and Intralipid less than or equal to 4 g/L; calcium is unaffected by bilirubin less than or equal to 600 mumol/L.
Testing for Creatine Kinase and Creatine Kinase-2 in Ontario: Reference Ranges and Assay Types
Authors: Henderson A R , McQueen M J , Patten R L , Krishnan S , Wood D E , Webb S 
Published: January 2020

Abstract
In 1991, 246 and 136 Ontario laboratories performed total creatine kinase (CK; EC 2.7.3.2) and creatine kinase-2 (CK-2) assays, respectively. A questionnaire mailed to these laboratories requested information about the types of assay used, the origin of their reference ranges, and the source of their instruments and reagents. All laboratories used current test formulations for CK, although seven laboratories did not assay at 37 degrees C. For CK, 69% of all laboratories reported different upper reference limits for men and women (5th-95th percentiles: 160-250 and 115-215 U/L, respectively); 31% reported similar ranges for both sexes. Fifty-six percent derived their own ranges; the remainder used either kit inserts or literature references, and nearly 60% of this latter group claimed to have validated these suggested ranges before use. For 6% of all laboratories, their pediatric ranges were similar to their adult ranges. For CK-2, only 32% used their own reference range; the remainder used kit inserts or literature references, but only 49% of this group validated these ranges before use. Reference limits (5th-95th percentiles) for CK-2 were as follows: activity 6-24 U/L; fraction of CK, 0.022-0.06; and, for mass assays, 5-10 micrograms/L and relative index 0.015-0.04.