bluuebunny/crossref_metadata_2025_split huggingface dataset:
Therapeutic drug monitoring of tricyclic antidepressants.
Authors: Preskorn S H , Dorey R C , Jerkovich G S 
Published: January 2020

Abstract
The traditional dose-response method of medication adjustment depends on several assumptions that are not met in the case of tricyclic antidepressants (TCAs), which makes therapeutic drug monitoring (TDM) particularly useful with these drugs. TDM can facilitate treatment by providing objective guidelines for dose adjustment. It provides a means of assessing compliance, ensuring an effective concentration, and avoiding toxicity. The latter is an often-overlooked benefit of therapeutic monitoring of TCAs and yet is just as important as improving response. The cardiac and central nervous system toxicity of TCAs is concentration-dependent and potentially life-threatening. Such toxicity will predictably occur in up to 5% of patients on standard antidepressant doses of TCAs when TDM is not used to rationally adjust the dose. Without TDM, such toxicity is difficult to detect early. A cost/benefit analysis supports the cost effectiveness of TDM as a standard part of TCA chemotherapy when doses in the 100-300 ng/day range are used.
Antidepressants in the treatment of post-psychotic depression in schizophrenia: drug interactions and other considerations.
Authors: Siris S G , Sellew A P , Frechen K , Cooper T B , Mandell J , Casey E 
Published: January 2020

Abstract
Adjunctive imipramine has been found to be useful in the treatment of a substantial number of patients with syndromally defined post-psychotic depressions. This paper examines the clinical effects of the combined anticholinergic activity of imipramine, when added to ongoing fluphenazine decanoate/benztropine treatment, in such patients. Little additional anticholinergic impact of the imipramine was observable beyond that already attributable to the benztropine, and no significant relationships were found between a clinical measure of peripheral anticholinergic activity and either global clinical outcome or antidepressive efficacy. This paper also reports on the concentrations of imipramine and its metabolites in plasma under the conditions of this therapeutic trial. The changes in relative concentrations of imipramine and metabolites with time were consistent with the concept that fluphenazine competes with tricyclic metabolism. The relationship of plasma imipramine and desipramine to clinical improvement in this group of secondary depressions did not parallel previously reported relationships of these antidepressant molecules to clinical outcome in primary depressions.
Compliance during tricyclic antidepressant therapy: pharmacokinetic and analytical issues.
Authors: Perel J M 
Published: January 2020

Abstract
Information on steady-state concentrations of parent tricyclic antidepressants (TCAs) and their major metabolites in plasma is useful in ascertaining compliance, for possible pharmacokinetic changes during longer treatment, and for prospective individualized dosing procedures. Adequate response can be maintained when there are relatively small fluctuations in drug concentration from visit to visit, but large fluctuations increase the liklihood of relapses during the acute-treatment phase and recurrences afterwards. Changes in the individualized in dosage regimens complicate measurement of concentrations in plasma at steady state. Longitudinal examinations of concentration/dosage (L/D) values in our three-year imipramine (IMI) maintenance study reveal that patients having large intra-individual fluctuations can be classified as noncompliers, likely to have recurrences. The time course and magnitude of L/D values reflect higher accumulation of both components, IMI and desipramine (DMI), in plasma. Evidently, dose-dependent kinetics lead to higher steady-state concentrations in plasma than previously observed with similar dosages in shorter-term treatment. With amitriptyline (AMI), in a 12-month study, the mean total concentrations of both AMI and nortriptyline (NT) progressively increased, by 22% and 33%, respectively. The pharmacokinetic linearity of AMI and (or) NT, i.e., (L/D)high/(L/D)low, is maintained over much wider dosage and age range than with IMI or DMI. We advocate concurrent use of the L/D method and co-administration of riboflavin for identification of noncompliers. We describe our current experience with various analytical procedures in this regard, concluding that high-performance liquid-chromatographic methods, with appropriate selection among ultraviolet, enhanced fluorescence, and electrochemical detectors for each TCA under specified therapeutic conditions, are most suitable and versatile, having superior analytical parameters. A suitable alternative procedure is gas-chromatography (N/P mode). Although immunoassays (EMIT, radiochemical) are most convenient for toxicological screens, their significant cross reactivities with several phenothiazines and the detection limits, requiring higher concentrations for EMIT, restrict their usage during research and (or) clinical monitoring.
Colorimetric assay of blood coagulation factor XIII in plasma.
Authors: Lee K N , Birckbichler P J , Patterson M K 
Published: January 2020

Abstract
In this new colorimetric assay for Factor XIII in plasma, 5-(biotinamido)pentylamine is used as the amine substrate. Factor XIII, a zymogen, is transformed by thrombin and Ca2+ to active Factor XIIIa, and the incorporation of 5-(biotinamido)pentylamine into N,N-dimethylcasein is used to measure catalytically active Factor XIIIa. The biotinylated enzymatic product is immobilized onto 96-well microtiter plates, complexed with streptavidin-beta-galactosidase, and the absorbance at 405 nm is monitored for production of p-nitrophenol from p-nitrophenyl-beta-D-galactopyranoside. Concentrations of N,N-dimethylcasein, 5-(biotinamido)pentylamine, Ca2+, and thrombin were chosen to allow near-maximum velocity of amine incorporation. A linear relationship was obtained between assay product and plasma volume, from 0.5 to 50 microL of plasma. Results correlated well (r greater than 0.924) with those from the most frequently utilized radiometric filter-paper assay for Factor XIII. The method appears to be ideal for routine diagnostic estimation of Factor XIII in plasma because of its simplicity, its lack of use of radioisotopes, and its potential for assay of large numbers of samples by use of microtiter plates and automated plate readers.
Isocratic separation of ATP and its degradation products from biological fluids by automated liquid chromatography.
Authors: Tekkanat K K , Fox I H 
Published: January 2020

Abstract
Two groups of metabolites (a) IMP, AMP, ADP, ATP, and cAMP in extracts of fibroblasts and erythrocytes and (b) hypoxanthine, xanthine, adenosine, and inosine in plasma and urine have been separated by ion-pairing reversed-phase chromatography on a microBondapak C18 column, with use of the following reagents: 60 mmol/L KH2PO4, 0.45 mmol/L tetrabutylammonium phosphate, and 1.26 mol/L acetonitrile, pH 3.2 (at 23 degrees C) (group a) and 20 mmol/L KH2PO4, 0.45 mmol/L tetrabutylammonium phosphate, and 0.35 mol/L acetonitrile, pH 2.70 (at 24 degrees C) (group b). Under both sets of conditions, the compounds are completely separated in less than 15 min. The separation is isocratic, so the method is easily adaptable to automation.
Determination of lamellar body size, number density, and concentration by differential light scattering from amniotic fluid: physical significance of A650.
Authors: Dubin S B 
Published: January 2020

Abstract
A new method for characterizing amniotic fluid is presented. The difference in optical absorbance between amniotic fluid diluted with distilled water or glycerol is measured. This differential approach is shown to determine the total light scattered by the surfactant-containing lamellar bodies and not to be affected by interfering chromogens. The lamellar body size, number density, and concentration are in turn quantified from the wavelength dependence of the absorbance difference, which is shown to be accurately predicted by light-scattering theory in the domain of "anomalous diffraction." The concentration of the lamellar bodies is demonstrated to be directly related to the absorbance difference at 650 nm. A maturity criterion, based on that generally accepted for the direct measurement of absorbance at 650 nm (that is, A650 greater than or equal to 0.15), is determined for the differential approach. Hence, measurement of the absorbance difference at 650 nm can be used to assess amniotic fluid both for its optical absorbance and its lamellar body concentration.
Autoantibodies to thyroxin and triiodothyronine.
Authors: Desai R K , Bredenkamp B , Jialal I , Omar M A , Rajput M C , Joubert S M 
Published: January 2020

Abstract
Two clinically euthyroid patients with multinodular goiter were found to have high "free" thyroxin (Amerlex-M, Amersham and Coat-a-Count, DPC) and triiodothyronine (Amerlex-M) concentrations (FT4 and FT3, respectively). The presence of antibodies to T4 and T3 was confirmed by the finding that polyethylene glycol precipitated a far greater proportion of radioactivity when radiolabeled FT4 or FT3 analog (Amerlex-M) was incubated with serum from these patients than was true for normal subjects. With this method we could not demonstrate antibodies to thyroid hormones in 116 healthy volunteers. Of 101 hyperthyroid patients tested, one had antibodies to T4 but none had antibodies to T3. One patient had antibodies to T4, and one to T3, of 36 hypothyroid patients tested. All patients with thyroid hormone antibodies also demonstrated antithyroglobulin antibodies (measured immunoradiometrically). Evidently, the presence of thyroid hormone antibodies should be suspected when results of thyroid-function tests are discordant with the clinical state, and we suggest that measurement of thyrotropin by an assay with improved detection limits will aid in correctly determining thyroid status.
Results for 74 substances tested for interference with determination of plasma catecholamines by "high-performance" liquid chromatography with electrochemical detection.
Authors: Koller M 
Published: January 2020

Abstract
Various catecholamine metabolites, catecholamine-related compounds, catechols, drugs, amines, and other nitrogen compounds were injected onto an HPLC system ("ClinRep Catecholamine-Plasma" assay kit with a reversed-phase C18 column) used for measuring catecholamines. None of the 74 substances tested co-eluted with any of the catecholamines--norepinephrine, epinephrine, or dopamine--or with the internal standard, 3,4-dihydroxybenzylamine.
More-sensitive enzyme-multiplied immunoassay technique for procainamide and N-acetylprocainamide in plasma, serum, and urine.
Authors: Henry P R , Dhruv R A 
Published: January 2020

Abstract
A commercially available (Syva Co.) enzyme-multiplied immunoassay technique (EMIT) for the quantitative determination of procainamide (PA) and N-acetylprocainamide (NAPA) was modified to allow automated quantitative analysis of approximately 100 samples per day, in a working range of 0.1 to 2.0 micrograms/mL. Such a test was needed to evaluate the pharmacokinetic characteristics of controlled-release dosage forms characterized by long half-lives at low plasma concentration. Analytical recovery of PA and NAPA from serum, plasma, and urine was satisfactory, but at extreme ratios for PA:NAPA the accuracy of determining the lower-concentration component became unsatisfactory. In fact, however, we found no such ratios in 5400 clinical samples assayed by this procedure.
Pseudouridine is unsuitable as an endogenous renal clearance marker.
Authors: Bernert J T , Bell C J , Guntupalli J , Hannon W H 
Published: January 2020

Abstract
We assessed the clearance of endogenous pseudouridine in humans to evaluate the potential use of this modified nucleoside as a marker of glomerular filtration rate. Pseudouridine concentrations in serum ultrafiltrates and in the corresponding 24-h urine specimens from 19 healthy men were determined by high-performance liquid chromatography. Mean (and SD) pseudouridine concentrations in serum and urine from this group averaged 2.77 (0.34) mumol/L and 203.2 (64.8) mumol/L, respectively. The calculated clearances of the nucleoside [87.3 (24.9) mL/min, n = 19], however, averaged approximately one-third lower than the corresponding creatinine clearances in the same individuals [131.8 (28.4) mL/min]. Measurement of simultaneous clearances of [3H]pseudouridine and [14C]inulin in rats also yielded a lower pseudouridine clearance, 0.78 relative to inulin. Our results are thus consistent with a partial net reabsorption of pseudouridine in both experimental animals and in humans, indicating that this compound would not be a suitable endogenous marker for routine estimation of the glomerular filtration rate.
Competitive enzyme inhibition immunoassay of apolipoprotein A-I: use of monoclonal antibodies.
Authors: Bekaert E D , Ayrault-Jarrier M , Petit E , Betourne C , Robin H , Polonovski J 
Published: January 2020

Abstract
An original competitive enzyme inhibition immunoassay has been developed for determination of total apolipoprotein A-I (apo A-I) in serum and in plasma. This specific assay involves a single monoclonal antibody (F59 4A12 2F4, directed to the -COOH terminal region of the apo A-I molecule) and a stable secondary plasma standard. Delipidation of serum samples exposed no additional antigenic sites, which suggests that all the apo A-I molecules express the epitope detected by Mab 4A12 on the surface of the apo A-I-containing particles. Within- and between-run CVs were, respectively, 6.1% and 7.5% at a 1.47 g/L concentration of apo A-I, 7.1% and 8.2% at 1.21 g/L, and 6.5% and 7.3% at 1.80 g/L. Results (y) correlated with those obtained with an electroimmunoassay (x), in which we used a mixture of three monoclonal antibodies, including Mab 4A12, as follows: y = 250x - 7, r = 0.744, P less than 0.001.
A method for direct estimation of imprecision profiles, with reference to immunoassay data.
Authors: Sadler W A , Smith M H , Legge H M 
Published: January 2020

Abstract
A three-parameter model for directly estimating imprecision profiles from replicated immunoassay results is compared with a six-parameter indirect profile model obtained by the usual method of combining error in the raw response measurements with the slope of the standard curve. Direct estimation is likely to be less reliable when based on the limited data collected from a single assay, and may underestimate variability at high concentrations when many results are clustered at the upper end of the concentration range. However, at concentrations near the assay detection limit (often a region of particular interest), direct estimation is superior to the indirect method if a logistic or related function is used as the standard curve model. Direct estimation of imprecision profiles has useful application whenever the internal details of an assay system are not readily available, for example, in analysis of data collected in external surveys.
Discriminant analysis of laboratory tests in patients admitted to a coronary care unit.
Authors: Lacher D A , Paolino M J 
Published: January 2020

Abstract
Discriminant analysis of chemistry and hematology laboratory test results was used to classify patients with and without myocardial infarction in a coronary care unit. We studied 64 patients with myocardial infarction and 70 patients without infarction, using logistic regression, linear and quadratic discriminant analyses on untransformed and logarithmically transformed data. Serum aspartate aminotransferase (AST, EC 2.6.1.1), the best single discriminating test, classified 73% of patients correctly. Quadratic discriminant analysis on log-transformed data had a 98.5% classification accuracy when all variables were used in the discriminant function and had the highest classification accuracy and precision. All of the discriminant methods had acceptable cross-validation.
Time series modeling for quality control in clinical chemistry.
Authors: Alwan L C , Bissell M G 
Published: January 2020

Abstract
Autocorrelation of clinical chemistry quality-control (Q/C) measurements causes one of the basic assumptions underlying the use of Levey-Jennings control charts to be violated and performance to be degraded. This is the requirement that the observations be statistically independent. We present a proposal for a new approach to statistical quality control that removes this difficulty. We propose to replace the current single control chart of raw Q/C data with two charts: (a) a common cause chart, representing a Box-Jenkins ARIMA time-series model of any underlying persisting nonrandomness in the process, and (b) a special cause chart of the residuals from the above model, which, being free of such persisting nonrandomness, fulfills the criteria for use of the standard Levey-Jennings plotting format and standard control rules. We provide a comparison of the performance of our proposed approach with that of current practice.
Sialic acid in sickle cell disease.
Authors: Ekeke G I , Ibeh G O 
Published: January 2020

Abstract
Neuraminic (sialic) acid concentrations in serum from normal and sickle cell (HbSS) subjects were determined for discrete age groups from childhood through adolescence. Values in sickle cell disease were consistently lower over the entire age range. We further investigated the effect of exogenous sialic acid on the rate of sickling reversion of HbSS erythrocytes and demonstrated that this compound in millimole per liter concentrations could revert pre-sickled erythrocytes to their normal morphology in a concentration-dependent manner. When subjected to partial de-sialation with sialidase (EC 3.2.1.18), the HbSS erythrocytes not only sickled faster upon deoxygenation, they also reverted more slowly on treatment with phenylalanine (a more efficient anti-sickling agent than sialic acid) than did untreated cells. We conclude that, in sickle cell disease, erythrocyte sialic acid content could play a significant role, not only in the control of the sickling rate in vivo, but also, after sickling has occurred, in the rate of recovery from a sickling crisis.
An inexpensive method for sensitive enzymatic determination of oxalate in urine and plasma.
Authors: Berckmans R J , Boer P 
Published: January 2020

Abstract
In this simple, sensitive, and rapid enzymatic method for the determination of oxalate in urine or plasma, oxalate oxidase (EC 1.2.3.4) prepared from barley seedlings is used to convert oxalate to carbon dioxide and hydrogen peroxide, which is determined photometrically at 600 nm, with use of horseradish peroxidase, by oxidative coupling of 3-methyl-2-benzothiazoline hydrazine with N,N-dimethylaniline. Plasma is pre-treated by ultrafiltration and co-precipitation of oxalate with calcium sulfate and ethanol, urine by dilution and reversed-phase chromatography on C18 columns. Analytical recovery for urine is 99 +/- 2%, for plasma 92 +/- 3%. The normal range for urinary excretion is 0.10 to 0.56 mmol/24 h, and for the concentration in plasma 0.4 to 3.7 mumol/L. There were no significant sex-related differences in urinary excretion or plasma concentration. Our within- and between-assay coefficients of variation were, respectively, less than 3.4% and less than 6.0% for urine, and less than 1.5% and less than 4.3% for plasma.
Modified TDx assay for cyclosporine and metabolites, for use with whole-blood samples.
Authors: Vogt W , Welsch I 
Published: January 2020

Abstract
A recently introduced fluorescence polarization immunoassay (FPIA) for determination of cyclosporine A in serum and plasma is discussed with regard to its use for whole-blood samples, with and without hemolysis before the assay. The performance characteristics of the modified method are highly satisfactory (within-run CVs 2.06 to 5.50% and 1.99 to 3.39%, respectively; long-term between-run CVs under routine conditions 5.73 to 8.95%). The limit of detection is 30 micrograms/L. Results agree well with those obtained with the RIAs compared, but the modified FPIA is more convenient and faster.
Improved liquid-chromatographic determination of cyclosporine and its metabolites in blood.
Authors: Shah A K , Sawchuk R J 
Published: January 2020

Abstract
We describe a liquid-chromatographic assay for cyclosporine (CyA) and four of its metabolites in blood. The method is sensitive and specific for this drug and its metabolites. The use of flow programming shortens total chromatographic run time to 30 min, resulting in acceptable separation of metabolites at a lower flow rate and yielding narrower peaks for CyA and the internal standard at the higher flow rate. CyA and metabolites Met 17 and Met 1 were measured in seven heart transplant patients who were undergoing chronic therapy with CyA in oral doses ranging from 3 to 13 mg/kg body wt per day. For the individual patients, the mean trough concentrations in blood of CyA, Met 17, and Met 1 ranged from 111 to 221, 159 to 334, and 36 to 90 micrograms/L, respectively. Met 8 and Met 21 were not observed in any of these patients' blood specimens.
A sensitive bioluminescent immunoinhibition test for CK-B subunit activity and a CK-MB specific ELISA compared: correlation with agarose electrophoresis and influence of CK-isoenzyme profile on results.
Authors: Gorus F , Claessens V , Goubert P , Laureys M 
Published: January 2020

Abstract
Searching for alternatives to the imprecise spectrophotometric tests for low-concentration creatine kinase (EC 2.7.3.2) isoenzyme MB (CK-MB), we investigated the analytical performance of two potentially superior approaches--a bioluminescent immunoinhibition assay (I, LKB-Wallac) and an ELISA (enzyme-labeled immunosorbent assay) technique (II, Hybritech)--in comparison with an electrophoretic method (III, Beckman). Only I showed good between-day precision (CV 8.3%) at the upper reference limit, allowing reproducible assay of CK-B subunit activity down to at least 3 U/L. In conditions where CK isoenzyme assays remained unaffected by CK-MM concentrations, test results were proportional to the amount of CK-MB in the sample up to at least 50 U/L for I, 120 micrograms/L for II, and 100 U/L for III (r greater than 0.998 by linear regression analysis). For CK-MB-positive samples, the data by I correlated more closely with values by III (n = 24; r = 0.994) than did results by II (n = 15; r = 0.909), but both methods were equally effective in discriminating between samples with or without electrophoretically supranormal CK-MB activity (93% sensitivity). II was entirely CK-MB specific, whereas CK-B activity by I was consistently (18/18) increased in CK-MB-negative samples containing CK-BB (n = 6; r = 0.996) or macro CK, types 1 or 2 (n = 12; r = 0.930). I is highly sensitive for screening for increased non-MM CK activity, the nature of which should be subsequently clarified by electrophoresis.