bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technical and clinical performance of six sensitive immunoradiometric assays of thyrotropin in serum.
Authors: Rodriguez-Espinosa J , Mora-Brugues J , Ordoñez-Llanos J , Cortes-Rius M , Queralto-Companyo J M , Gonzalez-Sastre F 
Published: January 2020

Abstract
We evaluated the analytical and clinical performance of six commercial immunoradiometric assay kits for thyrotropin (TSH) in serum in 218 subjects, with and without thyroid dysfunction. Detection limits of the six kits were lower (from 0.07 to 0.25 milli-int. unit/L) than that of conventional TSH RIA (0.7 milli-int. unit/L). Precision was adequate over a wide range of concentrations, although interassay CVs at very low concentrations were good for only two kits (7.3% and 13.1%). Results by all the kits correlated to about the same degree with the TSH RIA (r = 0.92 to 0.98). All showed a positive correlation between both the basal and post-thyroliberin (TRH)-stimulation values for TSH (r = 0.78 to 0.88), and all showed similar euthyroid reference ranges for basal concentrations of TSH. With four of the six kits we could clearly distinguish most of the hyperthyroid patients from healthy euthyroids; however, basal and post-TRH TSH values were not sufficient to discriminate among groups of patients with different grades of thyroid hyperfunction.
Interference in an electrochemical detection system for peroxidase-linked reactions based on a fluoride ion-selective electrode.
Authors: Cowell D C , Ford P A 
Published: January 2020

Abstract
Use of the fluoride ion-selective electrode as a detector in a linked glucose oxidase (EC 1.1.3.4)/peroxidase (EC 1.11.1.7) method for glucose was investigated for possible interference from sugars, metabolites, drugs, and anticoagulants. The CV for the method was 1.5% (SD 0.37 mmol/L) at a glucose concentration of 25.0 mmol/L. Interference was studied with glucose at this concentration, interference being defined as any result differing by more than +/- 3 SD. When present in concentrations of clinical relevance, interference from urea, uric acid, or acetaminophen would preclude the use of this detection system for routine analysis.
Activities of dipeptidyl peptidase II and dipeptidyl peptidase IV in mice with lupus erythematosus-like syndrome and in patients with lupus erythematosus and rheumatoid arthritis.
Authors: Hagihara M , Ohhashi M , Nagatsu T 
Published: January 2020

Abstract
We examined the activities of peptidases in plasma and tissues of the New Zealand Black (NZB) mouse as an animal model of human systemic lupus erythematosus, and also in serum from patients with rheumatoid arthritis and systemic lupus erythematosus. Activities of dipeptidyl peptidase II (DAP II) and post-proline cleaving enzyme (PPCE) were increased, and dipeptidyl peptidase IV (DAP IV) activity was decreased in plasma and spleen of NZB mice, as compared with the control BALB/c mice. Likewise, the activity of DAP II was increased and that of DAP IV was decreased in serum of patients with rheumatoid arthritis and systemic lupus erythematosus. These results indicate the importance of hydrolytic enzymes in the pathogenesis of autoimmune diseases.
Increased activities of creatine kinase and lactate dehydrogenase isoenzymes in a patient with metastatic ovarian tumor.
Authors: Ng R H , Ethirajan S , O'Neill M , Statland B E 
Published: January 2020

Abstract
A 50-year-old woman with metastatic rhabdomyosarcoma of the ovary had increased activities of creatine kinase (CK; EC 2.7.3.2), CK-MB isoenzyme, lactate dehydrogenase (LD; EC 1.1.1.27), and LD-2 isoenzyme in her serum. The isoenzyme activities did not show a pattern of increasing, then decreasing. Clinical findings, including electrocardiograms, did not support the diagnosis of myocardial infarction. We suggest that high activities of CK-MB and LD-2 in serum may serve as a marker of rhabdomyosarcoma.
Performance of an automated six-wavelength photometer (Radiometer OSM3) for routine measurement of hemoglobin derivatives.
Authors: Zijlstra W G , Buursma A , Zwart A 
Published: January 2020

Abstract
A new instrument for spectrophotometric determination of oxygen saturation (SO2) and the fractions of carboxyhemoglobin (FHbCO) and methemoglobin (FHi), the Hemoximeter OSM3 (Radiometer), was tested by comparative measurements with a multiwavelength method. We found that it gave reliable results for freshly drawn samples from patients. When samples with artificially induced high proportions of HbCO or Hi, or both, were introduced, results were still sufficiently accurate. The presence of sulfhemoglobin (SHb) seriously interfered with the measurement of SO2, FHbCO, and FHi, but the instrument reliably indicated its presence. Because SHb is rarely encountered, a reliable warning for its presence is adequate for clinical practice. Using the instrument in its fetal mode, we obtained accurate results for blood samples from newborns.
Effects of non-ionic and anionic detergents on lipid-associated tissue ferritin.
Authors: Cham B E , Roeser P , Nikles A 
Published: January 2020

Abstract
Lipid-associated ferritin from homogenates of guinea pig liver is released from its conjugate(s) by incubation with the non-ionic detergents Triton X-100 and Nonidet P-40 but not by incubation with the anionic detergent deoxycholate. The amount of lipid-associated ferritin released from its conjugate(s) depends on the concentration of the non-ionic detergents. At a final non-ionic detergent concentration of about 20 g/L, all lipid-associated ferritin is released from its conjugate(s) in a liver homogenate. The amount released is identical with the amount of the lipid-associated ferritin obtained by extraction of the same liver homogenate with a mixture of butanol and diisopropyl ether.
A rapid toxicology screen for emergency and routine care of patients.
Authors: Hamlin C R 
Published: January 2020

Abstract
I have adapted, for use with a centrifugal analyzer, reagents from 10 different EMIT (Syva Co.) enzyme immunoassay urine drug-detection kits, reagents from another five serum kits, and reagents for determining ethanol. Assays for individual drugs in 100 microL of urine and in 100 microL of serum are performed simultaneously rather than sequentially in less than 15 min, with one-tenth the usual amount of reactants (sample + reagents). These assays, when combined with other easily performed tests, provide a rapid toxicology screen well-suited for evaluating acute emergency patients, and for performing a small number of daily routine screens. The total screen requires 500 microL of urine and 500 microL of serum. I summarize my experience with this procedure in its first year of use, and discuss differences between testing for the care of patients compared with searching for evidence of illegal drug use.
Chemical assay of p-aminohippuric acid simplified by use of dimethylaminocinnamaldehyde in ethanol.
Authors: Schwartz L B , Gewertz B L , Bissell M G 
Published: January 2020

Abstract
We have developed a new and simple method of p-aminohippuric acid determination by use of dimethylaminocinnamaldehyde (DACA). It differs from previous methods using DACA in that the reaction is carried out in ethanol rather than in dilute acid. This results in deeper and more stable color development. We have used this method successfully to determine effective renal plasma flow in a clinical study of this variable in pregnant women.
Value of a spectroscopic "fecalogram" in determining the etiology of steatorrhea.
Authors: Peuchant E , Salles C , Jensen R 
Published: January 2020

Abstract
We have developed a "fecalogram" to present the analytical results for four characteristics of fecal specimens: dry weight, total nitrogen, total fat, and hydrolyzed fat, measured by near-infrared spectroscopy. This technique gives results as precise as those of more traditional analyses for these four components. The respective correlation coefficients are 0.973, 0.960, 0.974, and 0.978. The CVs for this technique range from 1.19% to 2.88%. Among the digestive disorders revealed by this fecalogram is steatorrhea, which can be differentiated as being of pancreatic or intestinal etiology. The percentage of total fat that is hydrolyzed is significantly (P less than 0.0001) greater in patients with malabsorption (greater than 70%) than in those with maldigestion (less than 70%).
Chemically blocked analog assays for free thyronines. I. The effect of chemical blockers on T4 analog and T4 binding by albumin and by thyroxin-binding globulin.
Authors: Witherspoon L R , el Shami A S , Shuler S E , Neely H , Sonnemaker R , Gilbert S S , Alyea K 
Published: January 2020

Abstract
Analog assays for free thyroxin (FT4) produce inaccurate results because the T4 analog is sequestered by albumin. Diagnostic Products Corp. (DPC) introduced the concept of chemically blocking analog-albumin binding in 1982. While DPC succeeded in eliminating albumin dependence, their 1985 version of chemically blocked FT4 assay appeared to be "thyroxin-binding globulin" (TBG) dependent, producing inappropriately low FT4 results with low TBG concentrations and high results with high TBG concentrations. We examined the effects of chemical blockers on albumin and TBG binding, using equilibrium dialysis to measure free fractions of T4 analog and T4. We then created FT4 assays in which various concentrations of chemical blockers were used to demonstrate their effects on FT4 estimates in patients with low or increased TBG concentrations or who were pregnant. We found that chemical blockers do displace T4 analog from albumin, but also displace T4 from albumin and, in high concentrations, from TBG as well. It is this displacement of T4 from TBG by chemical blockers that resulted in "TBG dependence" of DPC FT4 estimates. This problem has been corrected in currently available versions of the DPC FT4 kit.
Diagnostic efficiency of four lactate dehydrogenase isoenzyme-1 ratios in serum after myocardial infarction.
Authors: Loughlin J F , Krijnen P M , Jablonsky G , Leung F Y , Henderson A R 
Published: January 2020

Abstract
We compared the diagnostic efficacy of the ratios LD-1/LD-2, LD-1/LD-3, LD-1/LD-4, and LD-1/LD-5 in 69 documented cases of myocardial infarction. We used 149 patients with congestive heart failure and 67 patients with nonmyocardial infarct as controls. We used a computer program to produce receiver-operating characteristic curves, decision threshold plots, and likelihood ratios for these LD ratios at 6-h intervals up to 108 h after the onset of chest pain or hospital admission. All ratios in the myocardial infarction cases peaked around 36 h after the onset of chest pain, while those for the nonmyocardial and congestive cardiac failure cases did not change over the 108-h period. In all patients with infarctions, LD-1/LD-4 and LD-1/LD-5 increased by 1.7 times (when LD-1 was less than 40%) and 3.4 times (when LD-1 was greater than 40%), respectively, over control values. Optimum decision threshold values were obtained at 13-24 h (LD-1/LD-5), 31-36 h (LD-1/LD-4 and LD-1/LD-3), and 55-60 h (LD-1/LD-2) after onset of symptoms. The highest likelihood ratio was obtained with the LD-1/LD-4 ratio; therefore, we suggest that this is a better diagnostic test for myocardial infarction than LD-1/LD-2.
Detection frequency by thin-layer chromatography of phosphatidylglycerol in amniotic fluid with clinically functional pulmonary surfactant.
Authors: Spillman T , Cotton D B , Golunski E 
Published: January 2020

Abstract
Densitometric lecithin/sphingomyelin ratios (LSR) and the presence of phosphatidylglycerol (PG) were determined for 735 consecutively received amniotic fluids. Of the 371 fluids with "mature" LSR between 2.0 and 4.5, more than one-third lacked detectable PG. Clinical outcomes for the 305 of the total group that were delivered within 72 h of sampling were also determined. Respiratory distress syndrome (RDS) did not occur in the 239 cases with LSR greater than or equal to 2.0, even when, as in 43 instances, PG was not detected. When the LSR was greater than or equal to 2.0, transient tachypnea was more prevalent in the absence of detectable PG (PG detected, 3% transient tachypnea; PG undetected, 16% transient tachypnea). Of the 103 cases where PG was undetected, 58% exhibited no respiratory problems. Even in the 60 cases where the LSR was less than 2.0 and PG was not detected, 42% of the cases were free of respiratory problems. RDS did not occur in any case where PG was detected, even in the six where the LSR was less than 2.0. We evaluate these results in light of various contradictory reports in the literature.
Multicenter evaluation of human placental alkaline phosphatase as a possible tumor-associated antigen in serum.
Authors: De Broe M E , Pollet D E 
Published: January 2020

Abstract
Using a solid-phase monoclonal antibody enzyme immuno-assay, we evaluated in a multicenter study (18 laboratories) the utility of evaluating catalytic activity of human placental alkaline phosphatase (hPLAP, EC 3.1.3.1) in serum as a potential tumor marker. We determined hPLAP in serum samples from 130 patients with ovarian cancer, 79 patients with testicular cancer (53 seminoma testis, 26 nonseminoma testis), 537 patients with various other malignant diseases (95 lung, 39 gastrointestinal, 195 breast, 208 others), 291 patients with benign diseases, and 213 healthy controls. To assess the influence of smoking on hPLAP activity in serum, we evaluated 79 serum samples from patients with noncancerous diseases for whom smoking habits had been recorded. Our main findings are: (a) hPLAP activity is frequently increased (greater than 100 mU/L) in pre-operative serum samples from ovarian cancer patients (49%) and from testicular cancer patients (59% overall; 72% seminoma, 35% nonseminoma); (b) heavy smoking may increase hPLAP activity; (c) excluding heavy smokers, a 96% specificity for cancerous lesions was observed; (d) in patients with ovarian malignancies, CA 125 and hPLAP may behave as independent markers; and (e) in patients with seminoma, hPLAP is clearly more frequently increased than is beta-choriogonadotropin.
Improved measurement of free alpha subunit of glycoprotein hormones by assay with use of a monoclonal antibody.
Authors: Whitcomb R W , Sangha J S , Schneyer A L , Crowley W F 
Published: January 2020

Abstract
Any exploration of the physiology of secretion of free alpha subunit of glycoprotein hormones in humans requires a sensitive assay system that shows low cross reactivity with the intact hormones (lutropin, follitropin, thyrotropin, and choriogonadotropin). We established and validated such an assay system with a monoclonal antibody for detection of free alpha subunit in serum with better sensitivity (detection limit, 30 ng/L) and less cross reactivity (0.67% with intact human lutropin) than with available polyclonal antibody methods. Thus, the specific epitope recognized by this antibody apparently is exposed only on the free or uncombined form of alpha subunit and is concealed after non-covalent combination with any beta subunit. Using Western blot analysis, we show that most of the cross reactivity is probably the result of contamination of the human lutropin standard (obtained from the National Hormone and Pituitary Program, NIH) with small amounts of free alpha subunit. With such a specific and sensitive method, it should be possible to obtain more-precise information regarding the secretion of free alpha subunit.
A laboratory and clinical evaluation of an immunochemiluminometric assay of thyrotropin in serum.
Authors: Berry D J , Clark P M , Price C P 
Published: January 2020

Abstract
We evaluated an immunochemiluminometric assay for human thyrotropin. A chemiluminescent acridinium ester is used as a label, with magnetic-particle separation. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.07 milli-int. unit/L, with a working range of 0.5 to greater than 60.0 milli-int. units/L. Assay accuracy was good as judged from analytical recovery, analysis of external quality-assessment samples, and comparison with an enzyme-amplified immunoassay. There were no significant interferences or cross-reactivities. Twenty-four samples assayed showed aggregation of the magnetic particles. On re-assay, four of these samples showed a significant increase in the measured TSH by the luminescence assay. Assay time for 60 tubes was approximately 3.5 h with the use of a semi-automated luminometer. The reference interval, determined from data on 144 healthy euthyroid subjects, was 0.3-4.0 milli-int. units/L. Sixteen of 19 thyrotoxic patients showed clearly suppressed concentrations of thyrotropin in serum.
Age-related reference values for free amino acids in first morning urine specimens.
Authors: Parvy P R , Bardet J I , Rabier D M , Kamoun P P 
Published: January 2020

Abstract
We determined age-related reference values for urinary free amino acids (in mmol/mol creatinine) in first morning urine specimens from 360 control subjects who were divided into nine age groups: birth to 1 month, 1-6 months, 6-12 months, 1-2 years, 2-4 years, 4-7 years, 7-10 years, 10-13 years, and older than 13 years. Except for taurine and 3-methylhistidine, the concentration of all the amino acids decreased with increasing age. The use of these results to detect aminoacidopathies and tubulopathies is discussed.
Comparison of the compression strength of human vertebral bodies with the mass and density of apatite: a study by 31P NMR spectroscopy.
Authors: Brown C E , Srinivasan R , Sigmann P , Myklebust J B , Battocletti J H 
Published: January 2020

Abstract
The force needed to fracture individual human thoracic and lumbar vertebral bodies is compared with the mass and density of apatite. 31P NMR spectrometry was used to quantify the apatite, because it permits the mineral content of bone to be determined noninvasively with minimal nonspecific interference from the organic matrix or from variations in composition of the marrow. Experiments were performed with bones of similar structure and function from a single individual with no history of trabecular fractures, to compensate for the effects of the other variables that affect bone strength. The coefficient of correlation between compression strength and the volume density (i.e., g/cm3) of apatite was 0.95. The correlation of strength with the mass (i.e., grams) of apatite in a vertebral body also was reasonably good, r = 0.82, but correlations with areal density (i.e., g/cm2) and linear density (i.e., g/cm) were much poorer.
Demonstration of monoclonal IgE by isoelectric focusing: first reported case of IgE myeloma in Australia.
Authors: McLachlan R , Grigg A P , Cornell F N , Harris R A , Woodruff R K 
Published: January 2020

Abstract
A 56-year-old man who presented with back pain was diagnosed with multiple myeloma. Serum protein analysis by isoelectric focusing identified a monoclonal IgE lambda of unique spectrotype compared with other monoclonal immunoglobulins. The similarity of the spectrotype of this monoclonal IgE to that of two purified monoclonal IgEs suggests that these proteins have a characteristic spectrotype, sufficiently different from those of other immunoglobulin classes to allow its recognition.
Strategy to diagnose monoclonal gammopathies in serum: high-resolution electrophoresis, immunofixation, and kappa/lambda quantification.
Authors: Keren D F , Warren J S , Lowe J B 
Published: January 2020

Abstract
Identification of monoclonal gammopathies in serum has involved electrophoresis of serum proteins, immunoelectrophoresis (IEP), and quantification of IgG, IgA, and IgM. Recent innovations in technology--including high-resolution electrophoresis (HRE), immunofixation (IFX), and quantification of kappa- and lambda-containing immunoglobulins--allow for more rapid and precise assessment of serum for monoclonal proteins. We present a series of guidelines to determine when high-resolution electrophoresis and quantification of immunoglobulins (including kappa and lambda) are sufficient and when additional IFX is required to characterize the monoclonal gammopathy. Of the samples studied, 88% were correctly diagnosed by HRE with quantification of immunoglobulins and kappa/lambda; only 12% required that IFX be performed. The guidelines allow us to detect monoclonal gammopathies quicker and more efficiently by avoiding redundant IEP or IFX testing. For the vast majority of cases, these guidelines allow for a correct diagnosis within one day. After one year of follow-up since completion of the study, no undetected cases of monoclonal gammopathy have eventuated.
Stabilization of ascorbic acid in human plasma, and its liquid-chromatographic measurement.
Authors: Margolis S A , Davis T P 
Published: January 2020

Abstract
We describe two independent HPLC procedures for the rapid, accurate analysis for ascorbic acid in human plasma. No sample extraction or phase separation is required. We also describe a procedure for preparing a human plasma reference material for use in clinical laboratory analysis for ascorbic acid. The ascorbic acid in plasma can be determined in 15 min, with as little as 50 microL of sample. Analytical recoveries are near 100% with direct injection of deproteinized plasma. Extensive stability data under several conditions, with dithiothreitol as a preservative (antioxidant), indicate that ascorbic acid remains stable in stored plasma for as long as 57 weeks. CVs for round-robin analysis of 11 normal human blood samples by two independent methods were between 0.1% and 5.3%. These clinical samples appear to be stable for at least 50 days under the described conditions of stabilization and sample treatment. Finally, because ascorbic acid prepared by the described procedures is stable at room temperature for at least 18 h, these methods can be readily adapted to clinical laboratory automation at room temperature.
Nosocomial dysnatremia.
Authors: Neithercut W D , Spooner R J 
Published: January 2020

Abstract
Patients who exhibited both hyponatremia and hypernatremia during a single admission were identified by a review of their biochemistry data. The mortality of patients who developed either hypernatremia or hyponatremia, followed by the opposite abnormality within less than or equal to 10 days, was 42%. This was greater than the 8.2% mortality for an age-, sex-, and admission-matched normonatremic control group (P less than 0.01, chi 2). Eight of the 10 patients who died had had a change in the sodium concentration in serum greater than 20 mmol/L. The interval (days) between the maximum and minimum sodium concentrations in the survivors and those who died was not statistically different. We found no specific clinical features that could be used to predict the development of this biochemical abnormality.
Analytical problems encountered in determining aluminum status from hair in controls and hemodialyzed patients.
Authors: Chappuis P , Duhaux L , Paolaggi F , de Vernejoul M C , Rousselet F 
Published: January 2020

Abstract
The problems involved in evaluating aluminum concentrations in hair are reviewed, especially those concerning removal of contaminating metals, a critical factor. In the few published studies of Al concentrations in hair, acetone was usually used for its removal. Here, its use in the washing sequence was found to give less precise results and higher Al values than the use of isopropanol. With isopropanol, the whole analysis can be done in a single tube. We compared results with those in the literature. We found that the Al concentration in the hair of control subjects was not related to sex or hair color and that there was a highly significant (P less than 0.001) difference between values for control subjects and hemodialyzed patients: 126 (SD 58) nmol/g, n = 49, vs 226 (SD 104) nmol/g, n = 39, respectively.