bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastase inhibitory activity in serum of patients with thyroid dysfunction
Authors: Wortsman Jacobo , Matsuoka LolS V , Kueppers Friedrich 
Published: January 2020

Abstract
Dermal elastic fiber fragmentation and decreased fiber density are characteristic cutaneous abnormalities in myxedema. We therefore evaluated elastase inhibitory activity in serum in thyroid dysfunctional states by measuring the protease inhibitor alpha 1-antitrypsin (A-1-AT), as well as by directly determining the inhibition of porcine pancreatic elastase activity. Overall there was a strong correlation between A-1-AT concentration and elastase inhibitory activity in serum (r = 0.95, P less than 0.001). Mean (+/- SE) A-1-AT concentrations were greatest in hyperthyroidism (39 +/- 3 mumol/L, n = 13), followed by normal controls (29 +/- 1, n = 11), subclinical hypothyroidism (27 +/- 2, n = 7), and hypothyroidism (25 +/- 1, n = 12). Concentrations of both A-1-AT and porcine pancreatic elastase inhibitory activity were significantly greater in subjects with hyperthyroidism than in the other groups (P less than 0.01). The correlations (r) between the overall free thyroxin (T4) index and A-1-AT and elastase inhibitory activity were 0.68 and 0.61, respectively (P less than 0.01), implying that free T4 variations account for 46% of the variance in A-1-AT concentrations and 37% of the variance in elastase inhibitory activity. We conclude that serum elastase inhibitory activity is increased in hyperthyroid patients.
Urinary neopterin in patients with systemic lupus erythematosus
Authors: Leohirun Lakana , Thuvasethakul Phlchal , Sumethkul Vasant , Pholcharoen Trithar , Boonpucknavig VlJitr 
Published: January 2020

Abstract
Concentrations of neopterin were measured in urine specimens from 35 patients with active and eight with inactive systemic lupus erythematosus (SLE). Compared with those of apparently healthy controls, neopterin concentrations were higher in patients with active disease (P less than 0.001) and with inactive disease (P less than 0.01), those in patients with active disease being significantly higher than those in patients with inactive disease (P less than 0.001). The correlation between the neopterin concentration and evidence of disease activity was good. All of the patients with clinically active SLE had increased neopterin, but for only 37.5% (three of eight) did the neopterin concentration exceed the upper normal limit during clinical remission. The increase in neopterin concentration did not correlate with clinical courses or severity of renal function. Moreover, serial determinations of neopterin in active SLE patients showed a rapid decrease of initially high concentration, paralleling a decline of clinical activity after initiation of medical therapy. Thus, urinary neopterin may be a useful marker for monitoring disease activity in SLE patients.
Protein A-sepharose used to measure free insulin in plasma
Authors: Chevenne Didler , Valade Franclne , Bridel Marle-Pascal , Rigal Odlie , Demelier Jean-Francols , Sachs Charles , Porquet DomInique 
Published: January 2020

Abstract
Diabetic patients receiving insulin therapy generally develop anti-insulin antibodies that must be eliminated, usually by extraction with polyethylene glycol (PEG), before determining the concentration of free (active) insulin in plasma. We describe a new method for removing such antibodies, with the use of Protein A coupled to Sepharose microspheres. The results correlate well with those by the PEG method, although values are systematically higher or lower for given samples, according to the initial titer of the antibody measured in terms of binding capacity. Further studies are required to clarify this observation.
Excretion of beta 2-glycoprotein I (apolipoprotein H) in renal tubular disease
Authors: Norden A G W , Fulcher L M , Lapsley M , Flynn F V 
Published: January 2020

Abstract
beta 2-Glycoprotein I (beta 2GI) was identified as a major urinary protein excreted by patients with several renal tubular diseases, including adult Fanconi syndrome, nephrocalcinosis associated with autoimmune diseases, Lowe's syndrome, and Dent's disease (a familial renal tubular disease). Sixteen patients excreted between 2 and 40 mg of beta 2GI per millimole of creatinine. In contrast, 18 healthy controls had undetectable amounts of beta 2GI in urine. Isoelectric focusing followed by immunoblotting demonstrated multiple forms of beta 2GI with pls between 6.4 and 8.2. These pls are higher than for several other "tubular proteins"; beta 2GI may therefore be less retarded than more-anionic proteins by the glomerular charge-barrier. This could explain why large quantities of beta 2GI are excreted despite its relatively high molecular mass (50 kDa). Excretion of beta 2GI was easily demonstrated by routine electrophoresis of urine proteins. beta 2GI migrates in the beta-gamma region and may be confused with Bence Jones protein. beta 2GI is stable for at least two years in urine frozen at -25 degrees C.
Displacement of phenytoin from serum protein carriers by antibiotics: studies with ceftriaxone, nafcillin, and sulfamethoxazole
Authors: Dasgupta Amltava , Dennen David A , Dean Roger , McLawhon Ronald W 
Published: January 2020

Abstract
Increased concentrations of free phenytoin in serum, attributable to the displacement of this anticonvulsant by other drugs, e.g., valproic acid and salicylic acid, have been reported. We observed in vitro and in vivo displacement of phenytoin by the antibiotics ceftriaxone, nafcillin, and sulfamethoxazole. In vitro studies demonstrated statistically significant (P less than 0.05) increases in free phenytoin after the addition of specific antibiotics to patients' sera and to phenytoin-supplemented sera from controls. Concentrations of free phenytoin in vivo, predicted by an equation we have found to be accurate for albumin concentrations greater than or equal to 32 g/L, were consistently underestimated in patients receiving concomitant therapy with the antibiotics studied. The concentrations of free phenytoin decreased towards the predicted values when the antibiotic therapy was discontinued. We conclude that ceftriaxone, nafcillin, and sulfamethoxazole can displace phenytoin from the usual protein carriers found in serum, in vitro and in vivo.
Dry electrolyte-balanced heparinized syringes evaluated for determining ionized calcium and other electrolytes in whole blood
Authors: Toffaletti J , Ernst P , Hunt P , Abrams B 
Published: January 2020

Abstract
By analyzing whole blood containing no anticoagulants (uncoagulated whole blood) immediately after collection, we evaluated the relative changes in the concentrations of ionized calcium and other electrolytes in whole blood collected in dry heparinized syringes and in serum prepared from blood collected in evacuated blood-collection tubes. Using these dry heparinized syringes, we collected and analyzed whole blood that contained either 33 or 13 int. units of lithium heparin or 40 int. units of electrolyte-balanced heparin per milliliter of blood. We evaluated the effects both of these heparins at different concentrations of ionized calcium and of the incomplete filling of the syringes. We conclude that: (a) when analyzed within 2-3 min after collection, uncoagulated whole blood provides ionized calcium results unaffected by anticoagulants or cellular metabolism; (b) the preparation of serum unpredictably changes ionized calcium; (c) the use of dry electrolyte-balanced heparin virtually eliminates the interference in ionized calcium concentrations between 0.9 and 1.6 mmol/L; and (d) incomplete filling of electrolyte-balanced heparinized syringes produces no effect in syringes two-thirds full (60 int. units/mL heparin concentration) and a small effect in syringes one-third full (120 int. units/mL heparin).
Enzymatic method for measuring ethylene glycol with a centrifugal analyzer
Authors: Standefer J , Blackwell W 
Published: January 2020

Abstract
We describe a semiautomated, enzymatic method of analysis for ethylene glycol in plasma. Glycerol dehydrogenase (EC 1.1.1.6) from Enterobacter aerogenes, which has high specificity for ethylene glycol, is mixed with 3 microL of specimen in a centrifugal analyzer. NAD+ is added to initiate the reaction, and 450 s after an initial 90-s delay, the absorbance at 340 nm is measured. Monthly calibration with a five-point calibration curve is sufficient to provide between-day precision (CV) of 2% to 5%. The detection limit is 0.3 mmol/L with a CV of 10%. There is no significant interference from ethanol, methanol, isopropanol, acetone, lactate, or glycerol.
Major disagreements between immunoassays of carcinoembryonic antigen may be caused by nonspecific cross-reacting antigen 2 (NCA-2)
Authors: Börmer O P 
Published: January 2020

Abstract
Four "sandwich"-type immunoassays of carcinoembryonic antigen (CEA) based on the use of monoclonal antibodies (Abbott CEA-RIA Monoclonal, Pharmacia/Wallac Delfia CEA kit, Roche CEA EIA Duomab 60, and our in-house immunoradiometric assay) were tested for cross-reaction with nonspecific cross-reacting antigen 2 (NCA-2) in meconium. The Roche assay did not react with NCA-2, but the other three assays cross-reacted strongly and to about the same extent with this antigen. NCA-2 is the CEA gene family member that is structurally most similar to CEA, and other authors have found by indirect evidence that this antigen also is increased in the serum of many cancer patients. In a previous study we found that the Roche assay yielded lower mean values than the other assays for CEA in serum from colorectal cancer patients. Furthermore, the correlation between the Roche CEA values and those of each of the other three assays was weaker than the correlation between these NCA-2 cross-reactive assays. We conclude that these results can be explained by the different cross-reactivity with NCA-2 of the antibodies used by the various assays, as described here. Our findings raise interesting questions regarding the possible role of NCA-2 as a tumor marker.
Immunoreactivity of plasma parathyrin-related peptide: three region-specific radioimmunoassays and a two-site immunoradiometric assay compared
Authors: Ratcliffe W A , Norbury S , Stott R A , Heath D A , Ratcliffe J G 
Published: January 2020

Abstract
We measured parathyrin (parathyroid hormone)-related peptide (PTHRP) in plasma by three region-specific RIAs and compared them with an established two-site immunoradiometric assay (IRMA) of PTHRP1-86 in samples from control subjects and from patients with primary hyperparathyroidism (PH) and humoral hypercalcemia of malignancy (HHM). The two direct RIAs of PTHRP1-34 and PTHRP37-67 were specific for regions 9-18 and 52-61, respectively. In the extraction RIA of PTHRP1-34 we used an affinity gel containing a monoclonal antibody specific for the 17-27 sequence; cross-reacting PTHRP species eluted from the gel were assayed by the RIA of PTHRP1-34. PTHRP1-86 plasma concentrations by IRMA were less than 0.23 pmol/L in control subjects and patients with PH, and were significantly increased in patients with HHM (mean 6.1 pmol/L, P less than 0.001). In contrast, plasma PTHRP1-34 concentrations were not significantly different in the three groups; in HHM patients, the mean was 190 pmol/L. Plasma PTHRP37-67 concentrations were similar in control and PH groups and, although significantly increased in HHM patients (mean 440 pmol/L, P less than 0.002), showed poor diagnostic discrimination. PTHRP1-34 concentrations after affinity extraction of plasma were also significantly higher in HHM patients (mean 10.7 pmol/L, P less than 0.001), but showed incomplete diagnostic discrimination. We conclude that the diagnostic utility of the direct RIAs for quantifying PTHRP is markedly inferior to the IRMA of PTHRP1-86.
Adreno-medullary hypertension: a review of syndromes, pathophysiology, diagnosis, and treatment
Authors: Krakoff L R , Garbowit D 
Published: January 2020

Abstract
Hypertension may be attributable to various disorders involving the central or peripheral adrenergic (catecholamine) pathways. Pheochromocytoma is the best known of these disorders, but many syndromes mimic the clinical features of this tumor. In adreno-medullary hypertension, cardiovascular tissues are stimulated by activation of alpha or beta adrenergic receptors, or both. Specific diagnosis of adreno-medullary hypertension depends on careful clinical assessment and selection of sensitive and specific biochemical tests for measuring the catecholamines and their principal metabolites in urine or plasma. If such tests indicate the presence of a chromaffin cell neoplasm, accurate localization (imaging) is provided by computed axial tomography (CAT) or magnetic resonance imaging (MRI). Adreno-medullary hypertension is effectively controlled, pharmacologically, by alpha and beta receptor antagonists, which may be given intravenously for emergencies. Excess catecholamine synthesis by pheochromocytomas can be reduced by methyltyrosine. Surgical cure of pheochromocytomas can be expected in most instances, but long-term surveillance for recurrent tumors, some of which may be malignant, is needed. Chemotherapy can reduce the tumor bulk of a malignant pheochromocytoma. Recent use of molecular biology techniques may be helpful in early detection of malignant transformation.
Advances in catecholamine and metabolite measurements for diagnosis of pheochromocytoma
Authors: Rosano T G , Swift T A , Hayes L W 
Published: January 2020

Abstract
Assessment of catecholamine production and excretion is important in the laboratory detection of pheochromocytoma, a rare but curable cause of hypertension. Advances in catecholamine and metabolite methodologies have enhanced the diagnostic acumen by increasing analytical sensitivity and eliminating many of the interferences observed with earlier methods. Estimation of urinary catecholamines metanephrine and vanillylmandelic acid is routinely used in the biochemical detection of pheochromocytoma and in monitoring the completeness of tumor excision as well as the possibility of recurrence. Traditional spectrophotometric and fluorometric methods for urinary catecholamines and their metabolites are being replaced by highly sensitive and selective chromatographic methods. The ability to quantify individual catecholamines and metanephrines by high-performance liquid chromatography is of particular value for detecting familial forms of the tumor that may secrete epinephrine. Plasma norepinephrine and epinephrine measurements are of additional diagnostic value in determining recent catecholamine release and response to clonidine suppression. For either urine or plasma measurements, appropriate patient preparation, sample collection, and method validation along with an understanding of the variable pattern of catecholamine secretion and metabolism in pheochromocytoma are essential. Advances in laboratory methodology and reference intervals for catecholamines for clinical interpretation are reviewed.
Applications of ambulatory blood pressure monitoring in clinical practice
Authors: Weber M A , Smith D H , Neutel J M , Cheung D G 
Published: January 2020

Abstract
Traditionally, blood pressure has been measured by the sphygmomanometer in the medical office. There is growing evidence, however, that office blood pressures may not be typical of values throughout the day. Between 20% and 30% of patients diagnosed with hypertension in the office actually are normotensive at other times. Ambulatory blood pressure monitoring with small, portable devices that automatically measure blood pressure every few minutes throughout the day appears to be an appropriate tool when "white-coat" hypertension is suspected--i.e., for individuals whose hypertension in the physician's office is not associated with other physical or historical evidence for cardiovascular disease or with other risk factors. Used prudently, ambulatory monitoring is a cost-effective technique that potentially can prevent unnecessary treatment of patients. Moreover, whole-day measurements may correlate more closely than office measurements may correlate more closely than office measurements do with findings of cardiovascular disease. This new approach also has highlighted the circadian pattern of blood pressure, especially the sharp early to mid-morning increase that coincides with an increased tendency to major cardiovascular events. This has focused attention on directing antihypertensive therapy towards the morning hours. Ambulatory monitoring is now used routinely in studies of antihypertensive drugs. This technique has no placebo effect and takes fewer patients to assess drug efficacy than do conventional methods.
Temperature-dependent immunoreactive assay to screen for digoxin-like immunoreactive factor(s)
Authors: Guédeney X , Chanez C , Grenier A , Scherrmann J M 
Published: January 2020

Abstract
Endogenous circulating digoxin-like immunoreactive factors (DLIF) are known to cross-react with antibodies to digoxin and to inhibit Na+/K(+)-transporting ATPase (Na+K+ATPase; EC 3.6.1.37). Moreover, increasing the immunoassay temperature from 4 to 37 degrees C markedly decreases DLIF from human cord serum. We tested several compounds, including hormonal steroids, bile salts, lipids, and methionine-enkephalin, for their ability to cross-react with two commercially available 125I digoxin RIAs, to inhibit porcine Na+K+ATPase, and to see whether they present the same incubation temperature dependence as human cord serum. Except for methionine-enkephalin, all compounds were inhibitors of Na+K+ATPase in the range of 1-10 mmol/L. Progesterone exhibited the highest cross-reactivity in the two RIAs. The apparent digoxin immunoreactivity for the majority of the cross-reacting steroids, bile salts, and linoleic acid was markedly decreased by increasing the incubation temperature from 4 to 37 degrees C, whereas estriol, pregnanediol, and nonspecific compounds (e.g., ethanol, human serum albumin) did not appear to be temperature-sensitive. Both lysophosphatidyl lipids gave an increased apparent digoxin concentration with increasing incubation temperature. Our data suggest that numerous weakly cross-reactive compounds can parallel the response of human cord serum. However, the temperature-dependent effect could be an additional criterion for identifying DLIF.
Lactate dehydrogenase, creatine kinase, and their isoenzymes in pleural effusions
Authors: Paavonen T , Liippo K , Aronen H , Kiistala U 
Published: January 2020

Abstract
Lactate dehydrogenase (LD; EC 1.1.1.27) and creatine kinase (CK; EC 2.7.3.2) are widely distributed cytoplasmic enzymes. LD has five and CK has three isoenzymes distributed in different proportions in various tissues. The amounts of LD and CK and the distribution of isoenzymes in different body fluids are not thoroughly characterized. We have measured the total LD and CK concentrations and their isoenzyme distribution in pleural aspirates and in serum from 22 patients with benign conditions and from 14 patients with malignant effusions. In malignant pleural fluid, the mean total LD was 662 U/L; in benign conditions, it was nearly 5840 U/L with large variations (91-43 400 U/L) according to clinical diagnosis, the highest values being reached in inflammatory lesions. The mean total CK concentration in pleural fluid was close to the serum value in both groups of patients, as was the pleural CK isoenzyme distribution. The LD isoenzyme distribution in pleural effusions differed from that in serum in both groups, with LD-4 and -5 being the main isoenzymes in their pleural fluid specimens (greater than 42% of total LD). The total LD concentration correlated somewhat (r = 0.57) with the total pleural protein content. In conclusion, the pleural LD isoenzyme distribution, both in benign and malignant conditions, differs from that in serum, having shifted towards more anaerobic and embryonic isoenzymes (LD-4 and -5). Moreover, the greater the concentration of pleural total LD, the greater the proportion of LD-4 and -5. These data suggest that visceral or parietal pleural cells are rich in LD isoenzymes 4 and 5.
Use of immunoglobulin heavy-chain and light-chain measurements in a multicenter trial to investigate monoclonal components: II. Classification by use of computer-based algorithms
Authors: Jones R G , Aguzzi F , Bienvenu J , Gasparro C , Bergami M R , Bianchi P , Perinet A , Penn G , Keller I , Whicher J T 
Published: January 2020

Abstract
We describe a computer algorithm for classifying serum monoclonal proteins (MC) based on serum protein electrophoresis (SPE) and the automated measurement of kappa and lambda light chains and IgG, IgA, and IgM. We developed the algorithm by using a large database of unselected samples containing MC collected in a multicenter study. The performance of the algorithm was optimized by using iterative computational procedures and was tested on both the development database and on an independent set of MC-containing samples. With the development database, the algorithm correctly classified 50% and misassigned 2.5% of the MC. Where the MC were present in concentrations greater than 10 g/L, the rate of successful classification increased to 72% with 3% misclassification. When the algorithm was tested on a group of 101 MC-containing samples from an independent source, 67% were correctly classified and 8% misclassified, half of the latter being unusual IgD myelomas. We discuss the scope for the application of the algorithm in routine laboratory practice involving personal computer software.
Cholesterol operational process specifications for assuring the quality required by CLIA proficiency testing
Authors: Westgard J O , Wiebe D A 
Published: January 2020

Abstract
Current U.S. governmental regulations and requirements for the quality of laboratory tests do not provide a consistent form, comparable numbers, or practical specifications for the routine operation of laboratory testing processes. For cholesterol, as an example, the Health Care Financing Administration provides an analytical performance criterion for proficiency testing to enforce the Clinical Laboratory Improvement Act (CLIA), whereas the U.S. National Cholesterol Education Program (NCEP) provides clinical guidelines for test interpretation, as well as analytical goals for imprecision and inaccuracy. Routine operating process specifications for imprecision, inaccuracy, and quality control can be derived from the analytical and clinical requirements for quality. Use of an analytical "total error" model and a clinical "decision interval" model provides logically consistent and numerically comparable specifications. Studies with these coherent models indicate that a cholesterol testing process properly planned to satisfy the CLIA analytical requirement will also satisfy the NCEP clinical requirement. To provide 90% assurance of detecting systematic shifts of a magnitude that would cause the CLIA analytical requirement to be exceeded, the operational specifications for a cholesterol testing process are an allowable CV of less than or equal to 2%, an allowable bias of less than or equal to 1%, and a control procedure with two measurements per run interpreted by 1(3)s, 1(2.5)s, or 1(3)s/2(2)s/R4s control rules.