bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical evaluation of amperometric enzyme electrodes in continuous-flow analysis for glucose in undiluted whole blood
Authors: Gunasingham H , Tan C H , Aw T C 
Published: January 2020

Abstract
We have evaluated the carbon-paste enzyme/wall-jet electrode in continuous-flow analysis for glucose in undiluted whole blood. Responses of the electrode to protein-based and aqueous samples under wall-jet configuration are described. Imprecision in the flow-injection mode was less than 2% for glucose values in the usual analytical range (1-25 mmol/L). The dynamic range for glucose was from 0.03 to 45 mmol/L, with about 100% recovery of added substrate. The performance of the electrode (y) in flow-injection and steady-state modes was compared with a colorimetric method (x; Kodak Ektachem XR700), yielding linear-regression equations of y = 1.152x + 0.295 and y = 0.979x + 0.500, respectively. Among the anticoagulants, blood preservatives, and interfering substances investigated, only ascorbic acid gave a significant positive bias. The electrode exhibited good stability for analyses of undiluted whole-blood samples.
Effect of blood collection and processing on radioimmunoassay results for apolipoprotein B in plasma
Authors: Brown S A , Epps D F , Dunn J K , Sharrett A R , Patsch J R , Gotto A M , Patsch W 
Published: January 2020

Abstract
We studied the effects of different blood collection and processing procedures on quantification of apolipoprotein (apo) B by radioimmunoassay. High-density lipoprotein subfractions HDL3 and HDL2 and isolated apoA-I did not cross-react in the assay. Analytical recovery of apoB at different doses of very-low- and low-density lipoproteins were complete. Inter- and intra-assay coefficients of variation (CVs) averaged 7.4% and 6.0%, respectively. Blood from 20 subjects was collected into tubes containing EDTA alone or EDTA with antiproteolytic and antioxidant agents; one half of each plasma was separated immediately, half after 3 h at 4 degrees C. Regardless of the addition of protective agents or the time difference in separating plasma from other blood elements, freezing plasma at -70 degrees C decreased apoB content a similar amount, an average of 6.8%. This loss of apoB immunoreactivity was not related to apoB content in fresh plasma. Analysis of variance showed no differential effect on apoB content by the various additions to whole blood or plasma. No additional apoB content was lost in once-frozen aliquots of three human plasma pools during storage at -70 degrees C for up to 18 months. We conclude that concentrations of apoB in human plasma can be measured reliably after long-term storage, although the absolute value may decrease slightly as a result of freezing.
Medium-chain acyl-CoA dehydrogenase deficiency: a useful diagnosis five years after death
Authors: Bennett M J , Pollitt R J , Taitz L S , Variend S 
Published: January 2020

Abstract
We report a family in whom a fatal case of medium-chain acyl-CoA dehydrogenase (MCAD; EC 1.3.99.3) deficiency was diagnosed by enzymatic analysis of heart tissue that had been stored for five years. Three healthy siblings underwent subsequent investigation with the 3-phenylpropionic acid loading test. All siblings had been asymptomatic; however, one (age 2.5 years) excreted large amounts of 3-phenylpropionylglycine in response to the load and exhibited an organic aciduria consistent with the diagnosis of MCAD deficiency. The other two siblings did not demonstrate 3-phenylpropionylglycinuria after the loading test. This case underlines the importance of considering family history and using appropriate diagnostic tests in the recognition of hereditary metabolic disorders.
Multi-factor designs. IV. How multi-factor designs improve the estimate of total error by accounting for protocol-specific biases
Authors: Krouwer Jan S 
Published: January 2020

Abstract
Total error is often calculated as a combination of random error and fixed bias. However, the specific protocols used to estimate random error and fixed bias are themselves variable factors that can affect the estimate of total error. We refer to biases such as assay drift, sample-to-sample carryover, and reagent carryover as examples of fixed biases that are protocol-specific and distinguish them from other fixed biases. Failing to account for protocol-specific biases that are present will lead to incorrect estimates of total error when routine use of the assay involves a protocol different from that used to estimate total error. Multi-factor protocols are recommended to determine protocol-specific biases, which, if present, should be included in the estimate of total error.
Ion-chromatographic determination of L-tartrate in urine samples
Authors: Petrarulo Mlchele , Marangella Martino , Bianco Omalla , Linari Franco 
Published: January 2020

Abstract
We propose using ion chromatography to determine tartrate concentration in urine. A 100-microL sample of urine is diluted and injected into the chromatograph. Tartrate is eluted within 11.5 min as a distinct and well-resolved peak. The sensitivity of the standard procedure (signal-to-noise ratio, 3/1) is 30 mumol/L. The intra-run and interrun coefficients of variation are 2.5% and 4.1%, respectively. Mean analytical recovery of known amounts of added tartrate ranges between 94.2% and 104.0%. We investigated the specificity of the procedure by analyzing urine containing added dicarboxylic acids structurally related to tartrate. The reliability of the procedure makes it suitable for investigating tartrate metabolism, e.g., the potential role of tartrate as an inhibitor of crystallization in calcium nephrolithiasis.
Microtechnique for quantifying phenol in plasma by gas chromatography-mass spectrometry
Authors: Harrison L M , Morrison J E , Fennessey P V 
Published: January 2020

Abstract
Methods for detection and quantification of phenol have been developed primarily for use in environmental and industrial monitoring, given the widespread use of phenol as a disinfectant and antiseptic. Little information is available regarding concentrations of phenol in the blood of patients treated with phenol in regional nerve blocks (e.g., intrathecal) for temporary relief of pain or spasticity. We report a specific and sensitive method for quantifying phenol in plasma, using chemical derivatization and high-resolution capillary column gas chromatography in conjunction with mass spectrometry. The assay we describe was developed to monitor plasma concentrations of phenol in children given motor point nerve blocks with dilute phenol.
Role of vasopressin in clinical hypertension and congestive cardiac failure: interaction with the sympathetic nervous system
Authors: Gavras H 
Published: January 2020

Abstract
The pressor action of vasopressin (AVP) in humans was investigated with the specific anti-vasopressor V1 antagonist d(CH2)5-O(Me)-Tyr-AVP. A single 0.5-mg intravenous bolus of this agent inhibited the pressor effect of AVP by about 80%. Normally hydrated humans had no blood pressure response to this dose, but this agent did prevent the blood pressure rise in response to exogenous AVP given in doses up to 200 milli-units/kg. Patients with severe hypertension, especially that associated with end-stage renal disease, tended to respond with moderate increases in blood pressure and plasma AVP after sodium overload and had a modest blood pressure fall (10-20 mmHg) in response to a single intravenous bolus of the AVP antagonist. Patients with an impaired sympathetic nervous system had increased sensitivity to the pressor action of AVP, in keeping with knowledge derived from experimental studies. These data suggest an interaction between AVP and alpha-adrenergic function, whereby the latter tends to attenuate the pressor action of AVP although it facilitates the release of AVP in response to various stimuli. In patients with congestive heart failure, the direct pressor action of AVP appears to contribute to increased systemic vascular resistance in about 30% of cases, i.e., those with plasma AVP concentrations well above the normal range. In these subjects, circulating AVP concentrations correlated with a decrease in vascular resistance in response to the V1 antagonist.
Diabetic nephropathy: a disease causing and complicated by hypertension
Authors: Steffes M W , Mauer S M 
Published: January 2020

Abstract
In examining the pathophysiology underlying the development of hypertension in diabetes mellitus, it is important to draw clear distinctions between Type I and Type II diabetes. In patients with Type I diabetes, with a peak onset of disease early in the second decade of life, hypertension clearly represents the sequelae to the development of substantial renal lesions, especially in the glomerulus. Thus the prevalence of hypertension in those patients without substantial glomerular lesions approximates the incidence of hypertension in the general population (approximately 4%). In patients with Type II diabetes mellitus and onset generally later in adult life, an increase in blood pressure can often be demonstrated early after or even before diagnosis of the disease (most readily demonstrated in the Pima Indians). Furthermore, clear familial tendencies towards the development of nephropathic complications of diabetes can be shown. In patients with Type I disease, the fall in glomerular filtration rate parallels the fall in glomerular capillary surface available for filtration. This reduction in the peripheral glomerular capillary surface correlates well with the expansion of the mesangium, strongly implicating the mesangial expansion in the demise in renal function. For both Type I and Type II diabetes mellitus, the increase in albuminuria may reflect an opening of large pores in the glomerular basement membrane, thereby allowing serum proteins to cross into the filtration space.
Importance of creatinine analyses of urine when screening for abused drugs
Authors: Lafolie P , Beck O , Blennow G , Boréus L , Borg S , Elwin C E , Karlsson L , Odelius G , Hjemdahl P 
Published: January 2020

Abstract
We report here a simple method involving urine creatine measurements for testing authenticity and reducing false-negative results in urine testing for drugs of abuse. Urinary creatinine in consecutive patient samples (n = 176) ranged between 0.1 and 31.9 mmol/L (mean 9.8 +/- SD 6.2) and the osmolality in these urines ranged between 49 and 1183 mOsm/kg (mean 595 +/- SD 276). With other consecutive samples in which creatinine was (arbitrarily chosen) less than 4.3 mmol/L (n = 85), the correlation with osmolality was lower. In 10 randomly selected urine samples from different patients, all "clean" for all drugs of abuse in initial immunological drug testing with approved methodology (in which creatinine was less than 4.3 mmol/L and osmolality was less than 200 mOsm/kg), five patients turned out to be drug positive after a simple concentration by volume. In a formerly heavy smoker of cannabis, the excretion of cannabinoids and creatinine was monitored for 93 days. The substances showed very good correlation throughout this period (r = 0.93, P less than 0.001), whereas simple measurements of cannabinoid concentrations would have falsely indicated several relapses of cannabis abuse. Urine samples used in drug-abuse testing should be tested for creatinine; if creatinine is less than 4.0 mmol/L, negative results for drugs may not be valid.
Improvement of a direct spectrophotometric assay for routine determination of superoxide dismutase activity
Authors: Bolann B J , Ulvik R J 
Published: January 2020

Abstract
The growing interest in measuring superoxide dismutase (EC 1.15.1.1) in many diseases calls for useful routine assays. For this purpose, the direct spectrophotometric method of Marklund (J Biol Chem 1976;251:7504-7) was improved to offer an alternative to the imprecise, indirect assays currently used. The decay of O2.- (from KO2) at pH 9.5 was monitored as the decrease in delta A (delta A = A250nm-A360nm). Superoxide dismutase was determined from the pseudo-first-order rate constant of O2.- dismutation. The precision of the assay was improved by increasing the concentration of O2.- and expanding the interval for measurements of O2.- concentrations to 4-16 mumol/L. Other assay characteristics, including temperature, were also optimized. In hemolysate the assay had a within-day CV of 5.5-13% and a between-day CV of 4%. Mn-superoxide dismutase and some superoxide dismutase mimics are inhibited at alkaline pH. Therefore, the method is primarily recommended for Cu,Zn-superoxide dismutase.
Plasma Neopterin as an Adjunct to C-Reactive Protein in Assessment of Infection
Authors: Sheldon Joanna , Riches P G , Soni N , Jurges E , Gore M , Dadian G , Hobbs J R 
Published: January 2020

Abstract
C-reactive protein (CRP) concentrations are increased in plasma in people with inflammatory conditions and bacterial infections. Plasma neopterin concentrations are increased in people with bacterial septicemias, viral infections, and graft vs host disease. Plasma concentrations of CRP and neopterin were measured daily in 21 bone-marrow transplant (BMT) patients, 64 patients in intensive-care units (ICU), and 12 patients with squamous cell carcinoma of the head and neck (HN). In the BMT patients, plasma neopterin measurements in addition to CRP measurements allowed infectious episodes to be distinguished from graft vs host disease. In the ICU patients, increased concentrations of CRP were not specific for infection and the additional plasma neopterin measurements did not improve this specificity. In all three patient groups, the derivation of a neopterin/CRP ratio was of no clinical use. These three groups of patients showed patterns of CRP and neopterin concentrations characteristic of their underlying diseases, the BMT patients with the immunological activation of graft vs host disease showed predominantly increased concentrations of plasma neopterin, ICU patients with infectious and inflammatory conditions had increased concentrations of both CRP and neopterin in plasma, and the HN group with localized inflammation showed increased plasma concentrations of CRP without increases in neopterin.
Bile acids and conjugates identified in metabolic disorders by fast atom bombardment and tandem mass spectrometry
Authors: Libert Raymond , Hermans Dominique , Draye Jean-Pierre , Van Hoof Françols Van , Sokal Etienne , de Hoffmann Edmond 
Published: January 2020

Abstract
From a study of the collision-activated fragmentation of bile acids, a qualitative analytical method based on negative ion fast atom bombardment tandem mass spectrometry has been developed. The times for sample preparation and analyses are short. Both free and conjugated bile acids are detected as they occur in biological fluids, without derivatization. For identifying bile acids and conjugates, the method offers better specificity and sensitivity than does the fast atom bombardment mass spectrometric technique alone. Specific scan modes have been developed for the selective detection of taurine conjugates, Δ4-unsaturated taurine conjugates, Δ4-3-keto free acids and their glycine conjugates, free acids and glycine conjugates bearing a hydroxyl group at the C-12 position, sulfates of glycine and taurine conjugates, and a C29 dicarboxylic bile acid, specific for generalized peroxisomal disorders. Applications of this technique demonstrate its potential usefulness, principally in the diagnosis of several peroxisomal disorders.
New enzyme-linked immunosorbent assay for glycocalicin in plasma
Authors: Kunishima ShinjI , Hayashi Klyotaka , Kobayashi Sentaro , Naoe Tomokl , Ohno Ryuzo 
Published: January 2020

Abstract
A new sandwich-type enzyme-linked immunosorbent assay for quantifying glycocalicin, a proteolytic fragment of platelet membrane glycoprotein Ib, is described. The assay is based on the use of two monoclonal antibodies raised against glycoprotein Ib and involves the avidin-biotin technique. The detection limit is 7 micrograms/L and the range of glycocalicin determined in plasma is 0.01 to 1 mg/L. Assay time is 2 h. The intra-assay CV ranged from 3.6% to 5.2%, the interassay CV from 5.4% to 8.0%. Analytical recovery of purified glycocalicin added to a plasma pool averaged 96%. In 36 healthy subjects, the mean glycocalicin concentration in plasma was 0.36 (SD 0.07) mg/L (2.7 nmol/L). We conclude that this assay is suitable for measuring glycocalicin in plasma and is also more sensitive and precise than the previously published immunoassays based on competitive binding assay.
Complexes of creatine kinase and immunoglobulins in serum identified by a nonimmune binding method
Authors: Backer Egbert T , Hafkenscheid Jan C M , van Wermeskerken Robert K A 
Published: January 2020

Abstract
We have developed a method for identifying IgG-complexed creatine kinase (CK; EC 2.7.3.2) (IgG-CK) and IgA-complexed CK (IgA-CK) in serum. We used immobilized Protein G to bind IgG-CK and immobilized jacalin to bind IgA-CK, leaving noncomplexed CK in solution. The noncomplexed CK and total CK were measured kinetically. The results are reported as CK bound to immobilized Protein G and CK bound to immobilized jacalin. We validated the method by using sera determined immunochemically to contain IgG-CK, IgA-CK, mitochondrial CK (CKmt), and free CK-BB. We demonstrated concomitant binding of CK and approximately 99% of IgG, and of CK and approximately 87% of IgA. For CK bound to immobilized Protein G and to immobilized jacalin, intra- and interassay precisions ranged from 2.5% to 9.6%, and detection limits were less than 9 318 U/L in 40 sera containing IgG-CK, and CK bound to immobilized jacalin ranged from 10 to 59 U/L in eight sera containing IgA-CK. These ranges represent the activities of immunoglobulin-bound CK in the sera. In 13 sera containing CKmt and in eight sera containing free CK-BB, the binding of CK was less than 9 U/L. Evidently, this method is useful for identifying IgG-CK and IgA-CK in serum.
Plasma protein-bound sialic acid in patients with colorectal polyps of known histology
Authors: Shahangian Shahram , Fritsche Herbert A , Hughes John I , Foemmel Richard S , Katopodis Nonda 
Published: January 2020

Abstract
Protein-bound sialic acid (PBSA) was measured in serial plasma specimens from 62 healthy subjects, 48 patients with colorectal polyps, and 30 patients with colorectal adenocarcinomas. The mean plasma PBSA concentration in healthy smokers was significantly greater than that in healthy nonsmokers and healthy ex-smokers (P less than 0.0001). Villoglandular polyps were associated with higher plasma PBSA values than were the most benign hyperplastic polyps (P less than 0.025). Patients with the most neoplastic villoglandular and villous polyps had significantly greater (P less than 0.010-0.050) plasma PBSA values than healthy subjects. Polypectomy decreased the mean PBSA value significantly to the mean value for healthy subjects only for patients with villoglandular (P less than 0.010) or villous (P less than 0.050) polyps. Colorectal cancer patients had mean plasma PBSA concentrations significantly greater than those for the healthy subjects (P much less than 0.001) and the polyp patients (P much less than 0.001). Surgery significantly reduced (P less than 0.025) the mean PBSA value for the cancer patients to the mean PBSA value observed for the healthy subjects.
Simplified format for DNA probe-based tests
Authors: Bains William 
Published: January 2020

Abstract
The approach I describe to using DNA probes in diagnostic tests is simpler than most existing formats. DNA in a sample is labeled by chemical reaction with bisulfite and methylamine to generate a sulfonated derivative. The DNA need not be purified to do this. The labeled sample is then incubated with an unlabeled, purified probe DNA, which is immobilized to a solid support. The amount of label remaining on the solid support after washing is detected by a monoclonal antibody that recognizes modified cytosines. The intensity of the signal depends on the amount of target DNA in the sample. Detection limits depend on the amount of immobilized DNA and on the degree of physical entrapment of the labeled DNA in sample material, but can be as low as 5 pg. This format is well suited to automation for use with existing robotic enzyme immunoassay procedures.
Competitive particle concentration fluorescence immunoassay for measuring 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (lometrexol) in serum
Authors: Taber Larry D , O'Brien Peter , Bowsher Ronald R , Sportsman J Richard 
Published: January 2020

Abstract
A competitive particle concentration fluorescence immunoassay (PCFIA) is described for measuring 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (lometrexol; Lilly) in human serum. b-Phycoerythrin-labeled lometrexol competes with free lometrexol for binding to a limiting concentration of lometrexol-specific antibodies immobilized by a second antibody to submicrometer-diameter polystyrene particles in specially designed 96-well plates. Reaction particles are washed and concentrated onto filter membranes in the wells of the plates and the fluorescence is measured at 575 nm. The method, including sample preparation and data reduction, is automated and can be completed in less than 2 h. The assay has a standard curve maximum measurable concentration of 1000 micrograms/L and a minimum detectable concentration of 0.1 microgram/L. Analytical recovery of lometrexol in serum is quantitative at concentrations greater than 1 micrograms/L. Intra- and interassay coefficients of variation at 50 micrograms/L in serum are 7.1% (n = 9) and 7.5% (n = 33), respectively. The cross-reactivity of naturally occurring folates, folic acid analogs, and the anti-cancer agent methotrexate is minimal. We report the use of the PCFIA during Phase I clinical studies designed to evaluate the pharmacokinetics of lomextrexol after intravenous administration to cancer patients.
Comparison of nucleic acid hybridization and cytologic examination for detection of human papillomavirus infection, with evaluation of two commercially available hybridization kits
Authors: Chimera J A , Anderson S M , Noell H , Rizk V 
Published: January 2020

Abstract
Human papillomavirus (HPV) infections were detected by analyzing exfoliated cervical cells for HPV DNA by use of nucleic acid hybridization; the results were correlated with cytologic findings on Papanicolaou smears. HPV infection was diagnosed in 154 women (20%) by either morphologic evidence on cervical smears or nucleic acid hybridization. Many of these women (38%; 58/154) exhibited Papanicolaou smears with no morphologic evidence of HPV infection. In those patients with cytologic evidence of HPV infection, only 28% were positive for HPV DNA. HPV 16 and (or) 18 were the most common types (27%) detected in women with cervical intraepithelial neoplasia, whereas all HPV groups tested were equally represented in patients with normal cervical smears. We also present an assessment of 17,000 clinical specimens submitted to this laboratory for analysis of HPV DNA.