bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid-chromatographic assay of cefamandole in serum, urine, and dialysis fluid.
Authors: Bliss M , Mayersohn M 
Published: January 2020

Abstract
We describe a "high-performance" liquid-chromatographic assay for quantifying cefamandole in biological fluids from patients with renal impairment. Serum samples are deproteinized with acetonitrile, then extracted with dichloromethane; dialysis-fluid samples are injected directly; urine samples are diluted appropriately before injection onto the reversed-phase column. The mobile phase is a methanol/aqueous solution (31/69 by vol) containing 500 microL of phosphoric acid, 20 mmol of sodium sulfate, and 200 microL of triethylamine per liter, the mixture being adjusted to pH 6.0 with NaOH. Retention time for cefamandole is 12 min. Its peak is well resolved in highly contaminated samples from renally impaired subjects. The assay's selectivity, reproducibility (within-day and between-day CVs less than 8% in all three sample fluids), and sensitivity--0.5 mg/L in serum, 1.0 mg/L in dialysis fluid, and 5.0 mg/L in urine--make it applicable to pharmacokinetic studies.
A specific antibody to vasopressin in a man with concomitant resistance to treatment with Pitressin.
Authors: Bichet D G , Kortas C , Manzini C , Barjon J N 
Published: January 2020

Abstract
A 26-year-old man with complete neurogenic diabetes insipidus since age nine was initially treated with vasopressin (Pitressin Tannate in oil). At age 13, its dosages were progressively increased to control the patient's polyuria; minor allergic symptoms occurred after every such treatment. We incubated serial dilutions of the patient's plasma with 125I-labeled arginine-vasopressin and obtained a 50% specific binding for the plasma at a final dilution of 625-fold. Cross-reactivity studies showed that lysine-vasopressin was better recognized by the antibody than arginine-vasopressin. These results were attributed to large concentrations of lysine-vasopressin (pork vasopressin) in the Pitressin.
Standardizing clinical laboratory data for the development of transferable computer-based diagnostic programs.
Authors: Strike P W , Michaeloudis A , Green A J 
Published: January 2020

Abstract
The existence of systematic differences between test results obtained at different laboratories can compromise the development of generally accessible reference databases for interpretive pathology. We review approaches to the elimination of inter-laboratory bias from pathology test results through the use of standard unit transformations. A general transform procedure is described that will permit laboratories serving a common population to make use of reference data, decision rules, and computer-based interpretive programs developed around a larger clinical database than each of these test centers could amass for themselves.
One-step immunoassays for free (unbound) hormones: the effect of tracer binding by serum proteins.
Authors: Geiseler D , Chodha P , Ekins R 
Published: January 2020

Abstract
In binding assays for determination of free (non-protein-bound) hormones in serum or plasma, the influence of the measuring system on the original analyte concentration in the sample must be considered. In one- or single-step free-hormone immunoassays, the labeled analyte or analog-tracer not only is bound to the antibody, it also is bound, to some extent, to serum proteins. The dependence of the assay response on two unknown variables--the concentration of free analyte and the binding potential of serum for the tracer--introduces a bias between the actual (original) and measured hormone concentrations. The significance of this protein effect is described by mathematical modeling of the analyte-protein distribution in the assay system. The theoretical consideration is validated by a clearly defined one-step assay system for measurement of free-thyroxin concentration, with a labeled thyroxin-immunoglobulin conjugate used as tracer.
Simultaneous determination of cerebrospinal fluid oligoclonal bands and the "gamma-protein index" by agarose electrophoresis and densitometry.
Authors: French C A , Tracy R P , Rudick R A , Kraemer A M , Arvan D A 
Published: January 2020

Abstract
Oligoclonal bands were identified in electropherograms of cerebrospinal fluid, and the "gamma-protein index" was concurrently calculated from the same strip. For the index, an upper limit of normal of 0.66 was established. We compared results with the clinical diagnosis in 69 patients with multiple sclerosis and 48 control patients with other diseases. Sensitivity, specificity, and positive predictive values of 73%, 96%, and 96%, respectively, were obtained from the index. An abnormal index and the presence of oligoclonal bands combined increased the positive predictive value to 100%. This approach may allow adequate qualitative and quantitative assessment of gamma-globulin abnormalities in cerebrospinal fluid after a single laboratory procedure.
Implementation of a screening program for diagnosing open neural tube defects: selection, evaluation, and utilization of alpha-fetoprotein methodology.
Authors: Christensen R L , Rea M R , Kessler G , Crane J P , Valdes R 
Published: January 2020

Abstract
We evaluated and compared three different commercial kit immunoassays for alpha-fetoprotein (AFP) before we implemented our neural tube defect screening program. Each kit can be used with either serum or amniotic fluid. Analytical recovery ranges for AFP reference sera within each kit's standard curve limits (in kilo-int. units/L) were 97-108% (7.5-180) for the Kallestad kit, 77-101% (21.8-436) for Amersham, and 92-100% (0-177) for Hybritech. CVs, within each manufacturer's standard-curve limits, for combined intra-assay (amniotic fluid pools) and inter-assay (kit serum controls) averaged 3.6-7.3% (Kallestad), 2.4-9.3% (Amersham (y) kit results showed a correlation of r = 0.97, y = 1.05x + 5.5 kilo-int. units per liter of maternal serum (n = 66; range, 2.0-98.5). Gestational age did not influence these assay correlations. The Kallestad AFP assay demonstrated a maternal serum positivity rate of 2.9% at greater than or equal to 2.5 (n = 655) and 8.9% at less than 0.5 (n = 423) multiples of the median. All kits performed well analytically.
Relationships of cyclosporine concentrations in serum, whole blood, and bile after renal and hepatic transplantation.
Authors: Vine W , Flye M W , Jatlow P 
Published: January 2020

Abstract
"Trough" (minimum inter-dose) cyclosporine concentrations were measured by liquid chromatography in samples of serum and whole blood or bile obtained from renal- and hepatic-transplant patients. Overall, concentrations in whole blood correlated poorly with concentrations in concurrently obtained serum. The poor correlation also held for individual patients over time. The degree of variability observed for individuals is especially disconcerting. Although cyclosporine measurements in whole blood may mitigate time- and temperature-dependent changes in the drug's distribution after collection, concentrations in serum separated after distribution are less dependent on the cellular mass in blood, and may better reflect the amount of drug available to receptor sites. This consideration may be particularly important in the postoperative period, when fluctuations in the cellular mass of blood are frequent. Concentrations of cyclosporine were also determined in concurrently collected bile and serum samples after liver transplantation. Concentrations of unchanged drug in bile were variably higher than those in serum. Bile/serum concentration ratios ranged from 65/1 to 4.6/1. It is postulated that bile/blood concentration ratios may reflect liver function.
Use of monoclonal and polyclonal antibodies to detect prostatic acid phosphatase by immunoblotting.
Authors: Patel P C , Aubin L , Côte J 
Published: January 2020

Abstract
We investigated two techniques of immunoblotting--the Western blot and the dot blot--for use in detecting prostatic acid phosphatase (PAP, EC 3.1.3.2). We used polyclonal antisera to human PAP, produced in rabbits by hyperimmunization with purified PAP, and PAP-specific monoclonal antibodies in the immunoenzymatic protocols. We conclude that PAP can be readily detected by Western blots with use of polyclonal antisera, but not with monoclonal antibodies. On the other hand, using a dot blot assay, we could easily detect PAP with both polyclonal and monoclonal antibodies.
Gas-liquid chromatography of phencyclidine in serum, with nitrogen-phosphorus detection.
Authors: Werner M , Hertzman M , Pauley C J 
Published: January 2020

Abstract
We developed a two-step assay of phencyclidine (PCP), in which 2.5 mL of serum is adsorbed onto a disposable solid-phase extraction column and the eluted drug is determined by gas chromatography with nitrogen-phosphorus detection. Methapyriline is the internal standard. The detection limit of this technique is 0.5 microgram/L and the linear range exceeds 200 micrograms/L. Precision (CV) ranges from 30 to 10% with increasing concentration. No interferences were encountered in more than 400 clinical samples. The assay permits serial observation of low concentrations of the drug in serum for pharmacokinetic study and for quantitative clinical correlation with the Brief Psychiatric Rating Scale.
Simultaneous gas-chromatographic determination of free and acetyl-conjugated polyamines in urine.
Authors: van den Berg G A , Muskiet F A , Kingma A W , van der Slik W , Halie M R 
Published: January 2020

Abstract
A capillary gas-chromatographic method with nitrogen-phosphorus detection is used to determine simultaneously urinary 1,3-diaminopropane, monoacetyl-1,3-diaminopropane, putrescine, monoacetylputrescine, cadaverine, monoacetylcadaverine, spermidine, N1-acetylspermidine, N beta-acetylspermidine, spermine, N1-acetylspermine, isoputreanine, N-(3-aminopropyl)pyrrolidin-2-one, and putreanine. The compounds are isolated by adsorption onto silica and converted into their methyl-heptafluorobutyryl derivatives. We give quality-control data and age-dependent "normal" values for urinary excretion of these analytes from 51 apparently healthy control subjects. Normal values for 31 adults are compared with those reported in the literature. Monoacetyl-1,3-diaminopropane and N1-acetylspermine are identified by mass fragmentography. We applied the method to monitor chemotherapeutic treatment of a patient with advanced non-Hodgkin's lymphoma; we identified by mass spectrometry N1,N12-diacetylspermine in this patient's urine.
Are specimens with "at risk" biochemical profiles more likely to be infectious for hepatitis B virus?
Authors: Burnett L , Whitfield J B , Nightingale B N 
Published: January 2020

Abstract
The potential infectivity of 640 plasma specimens with various biochemical profiles was directly assessed by hepatitis B virus (HBV) DNA dot-hybridization. We found that specimens with "at risk" biochemical profiles typical of various forms of liver disease were not significantly more likely to carry HBV than the general patient population. Specimens containing HBV cannot be distinguished from non-infectious specimens by any simple biochemical tests, including aminotransferases and bilirubin. The only predictive feature of HBV-positive samples was that they were more likely to be labeled as "biohazardous" by the medical staff, but even this was not always the case.
Use of Mahalonobis generalized distance in interpreting low-resolution gas-chromatographic profiles of urinary steroids.
Authors: Davies T G , Griffin K E 
Published: January 2020

Abstract
We used low-resolution gas-chromatography of urinary steroid metabolites, as their trimethylsilyl ethers, in conjunction with the Mahalonobis generalized distance to assess the analyses in terms of a multivariate normal distribution in two populations of women: 18-50 years old and older. We compare the use of this method of interpretation, presenting several cases to illustrate the use of this approach in a routine clinical chemistry laboratory. The improved accuracy of classification as abnormals and to the ability to identify an analysis result as abnormal, even when values for all the analyses fall within the univariate 95% regions of each constituent.
Liquid-chromatographic determination of dolichols in urine.
Authors: Turpeinen U 
Published: January 2020

Abstract
A reversed-phase "high-performance" liquid chromatographic assay for dolichols-18, -19 and -20 in urine is described. Dolichols are extracted from urine by using C18 cartridges and are chromatographed with a mobile phase consisting of 2-propanol/methanol, the effluent being monitored at 210 nm. The useful lower limit of sensitivity for quantification is 4 pmol (5 ng) of each dolichol per 5-microL injection, corresponding to 1.6 nmol (2 ng) per liter of urine. Heneicosaprenol is satisfactory as the internal standard. Peak heights and the amounts of dolichols applied to the column are linearly related from 4 to 110 pmol. Mean analytical recovery was 71%. For three different concentrations the mean within-assay CV was 6.4%, the between-assay CV 11%. The normal reference interval of total dolichols found for healthy adults was 17-101 micrograms/24 h (n = 30) or 1.9-11 micrograms per millimole of creatinine (n = 39). I determined the distribution of the main dolichols in urine and applied the assay also for samples from alcoholics.
Simple spectrophotometric quantification of urinary excretion of glycosaminoglycan sulfates.
Authors: Panin G , Naia S , Dall'Amico R , Chiandetti L , Zachello F , Catassi C , Felici L , Coppa G V 
Published: January 2020

Abstract
We describe a simple, rapid, precise, and sensitive spectrophotometric method for measuring urinary glycosaminoglycan (GAG) sulfate excretion. The GAG sulfates are precipitated with cetylpyridinium chloride, resuspended in water, and mixed with the basic dye 1,9-dimethylmethylene blue to produce a complex with the polyanionic molecule of sulfated GAGs. Absorbance is read at 535 nm. The standard curve for reaction was linear up to 12 micrograms of the different GAGs: dermatan sulfate, heparan sulfate, keratan sulfate, chondroitin 4-sulfate, and chondroitin 6-sulfate. Within- and between-run precision (CV), measured at three different GAG concentrations (normal and pathological), varied from 1.6% to 2.5% and from 1.8% to 4.5%, respectively. Analytical recovery ranged from 71% to 107%. Urinary GAG excretion, measured by this procedure, correlates (r = 0.837; p less than 0.001) with the values obtained with the borate-carbazole reaction (Anal Biochem 1962;4:330-4).
Quality assessment of determinations of serum fructosamine in 33 clinical chemistry laboratories.
Authors: Baker J , Metcalf P , Tatnell M , Lever M , Johnson R 
Published: January 2020

Abstract
We investigated the analytical performance of fructosamine measurement in 33 routine clinical chemistry laboratories. We prepared 12 human control sera spanning a range of nondiabetic and diabetic fructosamine concentrations and assigned target values by using commercial reagents and a Cobas Bio centrifugal analyzer. Each control serum was analyzed by participating laboratories on two separate occasions. Averaged results were compared with target values, and systematic error was determined from slope and intercept regression coefficients. Overall, we found no significant (p greater than 0.05) slope or intercept bias, although slight nonlinearity was found with bichromatic instruments. Random error was determined from the standard error of estimate and from duplicate measurements. We found a median interlaboratory CV of 5.36% and similar analytical performance with all automated instruments used. The median random error with manual techniques was 18.1%. We conclude that fructosamine measurement as currently performed in routine laboratories is sufficiently accurate and reliable to function as an index of blood glucose control in diabetic patients.
Evaluation and comparison of commercially available pregnancy tests based on monoclonal antibodies to human choriogonadotropin.
Authors: Gelletlie R , Nielsen J B 
Published: January 2020

Abstract
We evaluated eight pregnancy tests: Tandem Icon, beta-hCG Rapid, Pregnastick (immunoenzymometric assays), Neo-Pregnosticon (direct hemagglutination), Pregnospia (sol particle immunoassay), Neo-Planotest (latex agglutination), Gravindex beta-hCG, and beta-hCG Slide Test (both latex-agglutination inhibition), all of which detect human choriogonadotropin (hCG) in urine. We investigated the limits of detection and the responses to the following substances: human lutropin, protein, and blood, and high concentrations of hCG. Using 100 patients' samples, we assessed the diagnostic specificity and sensitivity as well as the accuracy of each kit. The detection limits for Tandem Icon, beta-hCG Rapid, Neo-Pregnosticon, Pregnospia, Neo-Planotest, and Gravindex beta-hCG were as stated by the manufacturers. Only Neo-Planotest gave a false-positive result for lutropin. The three immunoenzymometric assays were not affected by protein or blood, but of these only Tandem Icon did not exhibit prozoning. The five other kits gave false-positive or false-negative results for protein and blood. Tandem Icon performed best, being quick and easy to use and without susceptibility to interfering substances.
Concentrations of zinc, iron, molybdenum, arsenic, and lithium in cerebrospinal fluid of patients with brain tumors.
Authors: el-Yazigi A , Al-Saleh I , Al-Mefty O 
Published: January 2020

Abstract
We used flameless atomic absorption spectrophotometry to measure concentrations of Fe, Mo, Li, As, and Zn in cerebrospinal fluid (CSF) of patients with malignant brain tumors benign brain tumors, non-brain malignant tumors and control (non-neoplastic disease) patients. Mean (and SD) concentrations (microgram/L) of these elements in the control group were 62.7 (28.7) for Fe, 6.8 (4.8) for Mo, 0.7 (2.0) for Li, 1.3 (0.7) for As, 7 (5.9) for Zn. We could detect Li in less than 53% of controls. Zn concentrations in CSF of patients with astrocytoma (malignant brain tumor), benign brain tumors, or non-brain tumors were significantly (p less than 0.05) less than in control patients; the ratios for mean concentrations of Zn in tumor patients/control patients for the above groups were 0.3, 0.20, and 0.17, respectively. Concentrations of As in CSF of patients with non-brain malignant tumors were significantly (p less than 0.05) higher than in the controls; the ratio for mean CSF concentration of As in patients with non-brain tumors/control patients was 2.9. Differences in the concentrations of Fe, Li, or Mo among the various groups were nonsignificant.
Laboratory assessment of three new monitors of blood glucose: Accu-Chek II, Glucometer II, and Glucoscan 2000.
Authors: Brooks K E , Rawal N , Henderson A R 
Published: January 2020

Abstract
We describe a laboratory assessment of three new monitors of blood glucose concentrations: the Boehringer "Accu-Chek II" (B), the Ames "Glucometer II" (A), and the Lifescan "Glucoscan 2000" (L). Inherent imprecision (CV) of each monitor was less than 2%. Maximum difference between individual monitors of the same type was less than or equal to 0.5 mmol/L. The volume of blood applied to the test strips is not critical, but duration of blood incubation or color development should be precise. Two types of test strips retained sufficient color 48 h after development to allow checking of the original measurement, and would be suitable as quality-control "spot" checks. Correlation coefficients for results for whole-blood glucose vs those for serum glucose (measured with the Beckman ASTRA-8) were: 0.992 (B), 0.967 (A), and 0.988 (L). Bias plots of these data showed positive bias for A (0.45 mmol/L) and L (0.17 mmol/L) in relation to serum-glucose measurements, but a negative bias of 0.32 mmol/L for B. Calibration solutions are not interchangeable. Although these versions of the monitors are probably not analytically superior to earlier models, they are easier to use.
Hemoglobin, electrolytes, and other major clinical laboratory analytes as measured with a physician's office analyzer, the Kodak DT60.
Authors: Hicks J M , Iosefsohn M 
Published: January 2020

Abstract
We evaluated the Kodak DT60 analyzer, to assess its suitability for use in the physician's office setting. The DT60 Analyzer is based on the same multilayer film technology as used in the Ektachem 400 and 700. We compared results obtained with DT60 for all the analyses currently available for use in this instrument (Na+, K+, Cl-, glucose, urea nitrogen, uric acid, total bilirubin, total protein, amylase, cholesterol, and triglycerides) with results from a Kodak Ektachem 700 Analyzer and from other laboratory procedures. Results for hemoglobin were compared with those from a Coulter Counter Analyzer. For all analytes, linearity of the standard curve for various dilutions of Ektachem calibrators was within the manufacturer's claims. CVs for within-run precision ranged from 0.8% to 5.4%, run-to-run CVs ranged from 1.6% to 7.5%. Except for amylase, comparisons with other methods were generally very good. The only interference we observed was that of hemoglobin in the bilirubin assay. Calibration was stable for longer than one month. We also compared the performance of a skilled operator with that of an unskilled operator and of a physician.
Stability of NADPH: effect of various factors on the kinetics of degradation.
Authors: Wu J T , Wu L H , Knight J A 
Published: January 2020

Abstract
Seeking to minimize degradation of NADPH during storage, reagent preparation, and assays, we investigated the effects of pH, temperature, and ionic strength as well as the effects of phosphate and acetate. NADH was also included for comparison. Our results indicate that the rate of degradation of NADPH is proportional most importantly to temperature and concentrations of hydronium ion, but also to concentrations of phosphate and acetate. The degradation rate decreased with increasing ionic strength at neutral pH, but increased slightly at lower pH. NADPH generally is less stable than NADH under the same conditions. The reaction orders with respect to hydronium ion and anions were near 1 for NADH degradation reactions, about 0.5 for NADPH. Rate constants for NADH and NADPH differed more at higher pH and lower phosphate and acetate concentrations.
Imprecision of quantification of serum protein fractions by electrophoresis on cellulose acetate.
Authors: Kahn S N , Strony L P 
Published: January 2020

Abstract
We studied the precision of densitometric quantification of the protein zones resolved by cellulose acetate electrophoresis. Replicate analyses of patients' samples by a single technologist showed mean CVs ranging from 2.9% for serum albumin to 9.5% for alpha 1-globulin. There were marked differences in measurements obtained by replicate analysis of the same samples by two experienced technologists. We calculated what changes in fractional concentrations would be analytically significant and concluded that densitometry of cellulose acetate electrophoretograms can only be semi-quantitative. We suggest that visual interpretation of high-resolution electrophoretic patterns by a trained observer can replace densitometry in most cases.
Loss of coproporphyrin by centrifuging urine samples before liquid-chromatography.
Authors: Hill R H , Bailey S L 
Published: January 2020

Abstract
We have previously reported a "high-performance" liquid-chromatographic procedure for urinary porphyrins. While attempting to automate this procedure, we discovered that coproporphyrin could be partly or completely lost from urine samples if they were centrifuged or filtered before analysis. The loss is related to the amount of precipitate in each sample, acidic urines showing the greatest losses. If samples are alkalinized before centrifugation, the loss is prevented.