bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early (chemical) diagnosis of bacterial meningitis--cerebrospinal fluid glucose, lactate, and lactate dehydrogenase compared.
Authors: Knight J A , Dudek S M , Haymond R E 
Published: January 2020

Abstract
Both lactate and lactate dehydrogenase are more sensitive as early indicators of bacterial meningitis than is glucose, and both appear to help differentiate aseptic from bacterial meningitis. In selected cases, lactate dehydrogenase may be more sensitive than lactate. We also give reference intervals for cerebrospinal fluid cell count, glucose, lactate, and lactate dehydrogenase.
Determination of sodium with ion-selective electrodes.
Authors: Levy G B 
Published: January 2020

Abstract
The advent of ion-selective electrodes made possible the potentiometry of sodium in serum and plasma. These methods were based on dilution of serum, as done in flame photometry, and the results were identical. Analysis of whole blood precludes dilution and so "direct" potentiometry was developed. Results by this technique are variable but tend to compensate for the spurious hyponatremias found by the "indirect" dilution methods due to displacement of volume by lipids and protein. However, there is no unambiguous theoretical basis on which to choose between the various direct ion-selective-electrode techniques and instruments. As an alternative, I propose use of current indirect methods, with numerical correction for the shift in normal sodium values in the presence of abnormal lipid and (or) protein. A table was constructed for making such corrections.
Adaptation of Prostatic-Group-Label Homogeneous Immunoassay to reagent-strip format.
Authors: Tyhach R J , Rupchock P A , Pendergrass J H , Skjold A C , Smith P J , Johnson R D , Albarella J P , Profitt J A 
Published: January 2020

Abstract
The Prostatic-Group-Label Immunoassay (PGLIA) technique has been incorporated into a reagent-strip format. We report use of flavin N6-(N'-2,4-dinitrophenyl-6-aminohexyl)adenine dinucleotide (DNP-FAD) as the prosthetic group derivative and 6-N-(2,4-dinitrophenyl)aminohexanoic acid (DNP-caproate) as the competing ligand. DNP-FAD not bound by antibody combines with glucose oxidase apoenzyme, which then reacts with glucose and oxygen, and gives color through a peroxidase-linked system. The rate of color generation is thus a function of the DNP-caproate concentration. PGLIA reagent strips are prepared by sequential impregnations of filter paper with an acetone solution of indicator (3,3',5,5'-tetramethylbenzidine); an aqueous solution containing glucose oxidase apoenzyme, the rest of the color generation system, stabilizers, and antibody to DNP; and a solution of DNP-FAD in n-propanol. This preparation permits effective antibody binding, and prevents premature interaction of immunoassay components. A quantitative color response to concentrations of DNP-caproate in the range of 1 to 8 mumol/L was demonstrated with these reagent strips. Prototype PGLIA reagent strips for theophylline and phenytoin have been successfully developed by substituting the appropriate FAD derivative and antibody for the corresponding reagents in the DNP model system.
A flexible, computer-controlled video microscope capable of quantitative spatial, temporal, and spectral measurements.
Authors: Rich E S , Wampler J E 
Published: January 2020

Abstract
A video microscope system has been constructed and tested that incorporates computer-controlled video cameras for high-resolution and low-light microscopy. The low-light camera system involves a dual microchannel plate-image intensifier capable of photon gain as high as 500 000 and a gated silicone-intensified target vidicon to achieve usable photon sensitivity with a noise equivalent signal of only 2 photons (500 nm) per pixel per second. We have compared the limitations and capabilities of this camera system with those of a high-resolution video camera and conventional photomicroscopy. Uses of the low-light camera coupled to a computer system include image acquisition of weak-light images from self-luminous specimens, fluorescence microscopy with weak exciting light, kinetic resolution of calcium-mediated events as monitored by the calcium-sensitive bioluminescence of aequorin, and spatially resolved spectroscopic measurements. Flexible use of this system in these various applications is possible because it allows operation with illumination intensities over a dynamic range of 100 000:1.
Fluorescence polarization immunoassay. iii. an automated system for therapeutic drug determination.
Authors: Jolley M E , Stroupe S D , Schwenzer K S , Wang C J , Lu-Steffes M , Hill H D , Popelka S R , Holen J T , Kelso D M 
Published: January 2020

Abstract
A fully automated system for performing fluorescence polarization immunoassay has been developed. Reagents for each assay are contained in coded reagent packs, and no reagent reconstitution is required. A common buffer is used for all assays, minimizing changeover and set-up times for each assay. A single sample may be assayed in 5 min, or 20 samples in 10 min. A single-tube blank subtraction for each sample results in highly precise polarization values and obviates sample interferences. We have used this method for assays of gentamicin, theophylline, phenytoin, and phenobarbital. CVs are 1-4%, and the results correlate well with those by other methods. Because of the instrument design and the stability of the reagents, daily calibration is not required; samples may therefore be run immediately upon receipt or batched as desired.
The hybridoma-an immunochemical laser.
Authors: David G S , Wang R , Bartholomew R , Sevier E D , Adams T H , Greene H E 
Published: January 2020

Abstract
The advent of hybridoma technology has provided the immunotechnologist a finely tunable instrument that should permit a marked advance in the immunologic sciences. The ability to choose the precise antibody required and the virtually unlimited availability of easily purified antibodies have already resulted in the simultaneous immunometric assay and potential reagents for immunoscintigraphy and immunotherapy. Using an antibody with a specific affinity and recognition for a specific antigenc determinant can greatly influence the shape and range of a radioimmunometric calibration curve. With monoclonal antibodies, assay systems based on immune complexes (e.g., turbidimetric assays and counterimmunoelectrophoresis) can be made more precise, thus permitting study of the basic physicochemical principles underlying the antigen-antibody reaction and the development of greatly improved quantitative assays. On the other hand, the ability to select an antibody exhibiting specific characteristics implies the necessity to select. One no longer has the luxury of using a mixture of antibodies, hoping to take advantage of the fact that some will have desirable secondary characteristics such as electrophoretic mobility or the ability to absorb to plastics.
Use of monoclonal antibodies for quantitative analysis of antigens in normal and neoplastic tissues.
Authors: Brown J P , Hellström K E , Hellström I 
Published: January 2020

Abstract
We describe two methods of analyzing tissues for cell-surface antigens identified by monoclonal antibodies. The first method is a binding assay, in which a membrane fraction prepared by differential centrifugation of a tissue homogenate is incubated with 125I-labeled antibody. The specificity of the observed binding is established by competition with unlabeled antibody. The second method, double-determinant immunoassay, involves two monoclonal antibodies that recognize two distinct epitopes of the antigen molecule. An immunoabsorbent prepared from one of the antibodies is incubated with a detergent lysate of the tissue. The immunoabsorbent is then washed and incubated with the 125I-labeled second antibody. In both assays the amount of radiolabeled antibody bound is proportional to the amount of antigen in the test sample, and the limit of detection is approximately 10 pg of antibody, corresponding to less than 1 fmol of antigen.
Immunoenzymometric assays for simultaneous quantitation and distribution of erythrocyte antigen.
Authors: Makler M T , Mlecko C R , Pesce A J 
Published: January 2020

Abstract
We describe an adaptation and modification of the enzyme-labeled immunosorbent assay (ELISA), which yields information on the quantity and distribution of surface antigens on erythrocytes. The distribution assay, named "ELADA" (for Enzyme-Linked Antigen Distribution Assay), involves use of an alkaline phosphatase-immunoglobulin conjugate with alpha-naphthol phosphate and a diazonium salt as substrate. The insoluble reaction product forms a complex on the cell surface at the location of the antigen. Antigens in aliquots from the same enzyme-immunoglobulin conjugate are quantified with the soluble substrate p-nitrophenyl phosphate. One can thus establish whether the distribution of erythrocyte antigens is random by examining the ELADA-stained cells with a scanning electron microscope. Combining the quantitative ELISA with measurements of cell numbers makes it possible to estimate the number of antibody molecules-and thus the number of antigenic sites per cell. By using various modified antisera, substituted naphthol phosphates with higher avidities, and reaction conditions designed to optimize the kinetic reaction, we have been able to resolve the enzyme product deposited on the antigenic site to within 20 nm. It is not always possible to decide whether each deposit represents a cluster of antigenic determinants or a single determinant; however, if the number of antibody sites is known from ELISA quantitation, information about the number of antibody sites per deposit can be ascertained.
Homogeneous fluorescent immunoassay with dry reagents.
Authors: Greenquist A C , Walter B , Li T M 
Published: January 2020

Abstract
We described an assay for theophylline in serum in which the reagents for the substrate-labeled fluorescent immunoassay procedure are dry reagents in a paper matrix. This assay format is both rapid and convenient. In one such paper strip assay, the competing drug conjugate is present in the diluting buffer (dilution-into-conjugate strip assay); in another, all necessary assay reagents are contained on the strip (integral strip assay). The latter strip can be prepared by using appropriate solvents in a "two-dip" procedure, which prevents premature reaction of the assay constituents. The dilution-into-conjugates strip assays yield results that compare well with those by the corresponding solution assay (r = 0.975, standard error of estimate = 1.67 mg/L) and by "high-performance" liquid chromatography (r = 0.980, standard error of estimate = 1.49 mg/L). The integral strip results were compared with those by an enzyme immunoassay for theophylline (r = 0.990, standard error of estimate = 2.07 mg/L). Both strip assays require only a single dilution step before analysis.
Measurements of serum colloid osmotic pressure are of limited usefulness.
Authors: Duncan A , Young D S 
Published: January 2020

Abstract
We examined the usefulness of serum colloid osmotic pressure measurement in patients with chronic rather than acutely occurring low serum protein concentrations. We used two oncometers, the IL 186 Weil Oncometer and the Wescor Model 4100; results from the two instruments were interchangeable. Values for the colloid osmotic pressure were compared with those for serum total protein (r = 0.783) and albumin concentrations (r = 0.882), which were similar to previously published values. Our day-to-day CV was 2.8%. In studying over 100 patients we found that the previously reported occurrence of pulmonary edema in almost all patients whose colloid osmotic pressure was less than 12.5 mmHg was not seen in the chronic hypoproteinemic patients. We noted only one fatality in our patients whose colloid osmotic pressure was less than 10.5 mmHg, a value found to be associated with fatality in one previous study of acutely ill patients. Factors such as ambulation, fasting, dehydration, and the nature of the blood sample can markedly affect the value for colloid osmotic pressure value, and this, coupled with the good correlation with the serum albumin in several studies, leads us to question the usefulness of measuring colloid osmotic pressure in a non-specialist hospital environment, either as an adjunct to the measurement of serum protein or albumin, or as an independent test.
Two serum pancreatic isoamylase determinations compared.
Authors: Rammeloo T , van Haard P M , Beunis M H 
Published: January 2020

Abstract
Serum pancreatic isoamylase activity was measured by a method involving inhibition of salivary isoamylase and by a well-known agarose electrophoretic method, modified by us. We saw changes in electrophoretic patterns of pancreatic isoamylase fractions after storage of serum samples for three weeks at 4-8 degrees C, but with the inhibition method no alterations in activities were found. Within-assay and between-assay imprecisions of both methods were about the same. Serum pancreatic amylase activities as measured by the inhibition method exceeded by about 10% those obtained by the electrophoretic method. The inhibition method seems to be a reasonable candidate for routine application, whereas the electrophoretic method is still time-consuming and requires special skill to perform. Some suggestions are given for improving the calibration of the inhibition method recommended by the manufacturer.
Effect of duration and temperature of storage on serum analyte stability: examination of 14 selected radioimmunoassay procedures.
Authors: Kubasik N P , Ricotta M , Hunter T , Sine H E 
Published: January 2020

Abstract
We determined appropriate temperatures for sample storage and the resulting stability of 14 analytes commonly radioimmunoassayed in the clinical laboratory. Serum specimens to be tested for concentrations of cholylglycine, cortisol, digoxin, ferritin, follitropin, immunoglobulin E, lutropin, prolactin, thyroxin (also blood-spot thyroxin), triiodothyronine, and triiodothyronine uptake could be stored for up to two weeks at room temperature, refrigerated, or frozen without any loss of analyte activity. Specimens for insulin testing require freezing or refrigeration, and specimens for gastrin testing should be stored at -70 degrees C for optimal results.
Fluorometry of selenium in serum or urine.
Authors: Lalonde L , Jean Y , Roberts K D , Chapdelaine A , Bleau G 
Published: January 2020

Abstract
This fluorometric procedure for determining selenium in human serum or urine is sensitive (requiring only 0.4 mL of sample), accurate, simple, and can be performed on several samples concurrently. Using this technique, we found a mean selenium concentration in the serum of normal Canadian men of 142.9 (SD 16.1) micrograms/L. The mean urinary excretion rate was 124.5 (SD 76.0) micrograms/day.
Macro creatine kinase: determination and differentiation of two types by their activation energies.
Authors: Stein W , Bohner J , Steinhart R , Eggstein M 
Published: January 2020

Abstract
Determination of the MB isoenzyme of creatine kinase in patients with acute myocardial infarction may be disturbed by the presence of macro creatine kinase. The relative molecular mass of this form of creatine kinase in human serum is at least threefold that of the ordinary enzyme, and it is more thermostable. Here we describe our method for determination of macro creatine kinases and an easy-to-perform test for differentiating two forms of macro creatine kinase, based on their distinct activation energies. The activation energies of serum enzymes are mostly in the range of 40-65 kJ/mol of substrate. Unlike normal cytoplasmatic creatine kinases and IgG-linked CK-BB (macro creatine kinase type 1) a second form of macro creatine kinase (macro creatine kinase type 2) shows activation energies greater than 80 kJ/mol of substrate. The exact composition of macro creatine kinase type 2 is still unknown, but there is good reason to believe that it is of mitochondrial origin.
Glucose determinations in plasma and serum: potential error related to increased hematocrit.
Authors: Sidebottom R A , Williams P R , Kanarek K S 
Published: January 2020

Abstract
This study reports the effect of increased hematocrit (packed cell volume) on the rate of decrease in plasma glucose during 6 h in blood specimens from seven newborns (cord blood) and heparin-treated blood specimens from eight adults. Mean hematocrits ranged frm 0.43 to 0.75 for the adults and from 0.51 to 0.81 for the infants. The decrease in glucose was related to time and to hematocrit. For example, in adults with a mean hematocrit of 0.43, glucose decreased from 890 +/- 40 mg/L to 570 +/- 30 mg/L (mean +/- SEM) at 6 h, whereas in adults with a mean hematocrit of 0.75, glucose decreased from 890 +/- 40 to 200 +/- 30 mg/L. In infants with a mean hematocrit of 0.51, glucose decreased from 1010 +/- 20 to 480 +/- 70 mg/L at 6 h; infants with a mean hematocrit of 0.81 had blood glucose decrease from 1010 +/- 20 to 50 +/- 30 mg/L. These results indicate that the incidence of hypoglycemia in infants with polycythemia may be overestimated, and emphasize the need for prompt handling of blood samples collected from newborns for glucose determinations.
Enzymic determination of citrate in serum and urine, with use of the Worthington "ultrafree" device.
Authors: Tompkins D , Toffaletti J 
Published: January 2020

Abstract
We describe an enzymic method for conveniently measuring citrate in serum or urine. Interfering enzyme proteins are removed by a disposable ultrafilter ("Ultrafree"; Worthington Diagnostics), obviating the need for hazardous protein precipitants. A 50 mmol/L Tris buffer adequately controls pH, no lactate dehydrogenase is necessary in the reagents, and the reaction of citrate catalyzed by citrate lyase (EC 4.1.3.6) is complete in 2-3 min. Within-run and day-to-day coefficients of variation were 7.5% and 5.4%, respectively. Serum citrate concentrations for 20 apparently healthy persons ranged from 0.08 to 0.17 mmol/L (mean 0.12, SD 0.03). Urinary citrate excretion by six normal volunteers ranged from 2.2 to 4.4 mmol/24 h. We observed no detectable changes in citrate in whole blood stored at room temperature for 90 min or longer. Overall, the method is faster and less hazardous than other methods for citrate that require protein precipitation.
Effect of sample instability on glycohemoglobin (HbA1) measured by cation-exchange chromatography.
Authors: Simon M , Hoover J D 
Published: January 2020

Abstract
We compared results for glycohemoglobin obtained from fresh whole blood or separated erythrocyte samples with results obtained after storage. We judged the storage condition to be acceptable ("stable") if the glycohemoglobin results after storage were within the 95 confidence interval (+/- SD) of the results obtained for the specimens on the day of venipuncture. Hemolysates can validly be stored for five months at -70 degrees C. Whole-blood samples stored at 4 degrees C remain stable for four days; whole blood treated with heparin or EDTA (but not oxalate) is stable for seven days. At 30 degrees C, whole blood or erythrocytes from some donors are stable for one day, but after two days and seven days, results are frequently higher. We confirmed previous findings that the separated erythrocytes can be stored at -20 degrees C for at least seven days. In addition, we compared the elution profiles for stored samples showing increased values.
Quantitation of urinary normetanephrine and metanephrine by reversed-phase extraction and mass-fragmentographic analysis.
Authors: Canfell C , Binder S R , Khayam-Bashi H 
Published: January 2020

Abstract
Hydrolyzed urine with added ring-trideuterated normetanephrine and metanephrine is applied to wet C18-reversed-phase minicolumns. The "metanephrines" are eluted, dried, derivatized with pentafluoropropionic anhydride, and analyzed with the gas chromatograph-mass spectrometer. Ions for the nondeuterated and trideuterated compounds are monitored at ml z 458 and 461, respectively. For both normetanephrine and metanephrine, the standard curve is linear over the range 10-2000 micrograms/L and the procedure has adequate precision both within-run (CV less than 3%) and between-day (CV less than 7%). Alkaline pH in the extraction is important for optimal analytical recovery. We have examined the potential value of untimed urine specimens for screening purposes and compared 24-h urine concentrations of these analyses in normotensive and hypertensive persons.
Liquid-chromatographic determination of ethylene glycol in plasma.
Authors: Gupta R N , Eng F , Gupta M L 
Published: January 2020

Abstract
In this novel procedure for determining ethylene glycol in plasma by liquid chromatography, benzoyl esters of ethylene glycol and of benzyl alcohol (used as the internal standard) are prepared directly in plasma. The benzoyl esters, highly ultraviolet-absorbing chromogens, are ideal compounds for analysis by reversed-phase liquid chromatography with methanol/water as the mobile phase. The benzoyl derivative of ethylene glycol is well separated from the derivative of the internal standard and from plasma constituents. The standard curve is linear to 400 mg of ethylene glycol per liter. As little as 10 mg of ethylene glycol per liter of plasma can be measured. Other commonly ingested alcohols do not interfere.
Electrophoretic determination of isoamylases in serum with commercially available reagents.
Authors: Leclerc P , Forest J C 
Published: January 2020

Abstract
We describe and evaluate a method for determining isoamylases in serum. With this method, which involves conventional electrophoretic apparatus and commercially available reagents, seven isoenzymes can be resolved. The electrophoresis is performed in agarose gel, and isoenzymes are detected with a water-insoluble cross-linked starch polymer linked to a blue dye. The isoenzymes are quantified by densitometry. Within-assay imprecision (CV) was less than 7%, between-assay CV less than 11%. This method has the sensitivity to detect the major isoamylases (P2 and S2) in the serum, even at low total amylase activity. Reference intervals for P-type isoenzymes were 2-52 U/L and for S-type 2-85 U/L. P2S2 is the most common pattern found in normal individuals, then (in decreasing order) P1P2S2, P2S2S3, and P2 patterns. Patterns found in serum from cases of acute pancreatitis, mumps, macroamylasemia, and pelvic inflammatory disease are illustrated.
Characterization of uremic "middle molecular" fractions by gas chromatography, mass spectrometry, isotachophoresis, and liquid chromatography.
Authors: Schoots A C , Mikkers F E , Claessens H A , De Smet R , Van Landschoot N , Ringoir S M 
Published: January 2020

Abstract
Uremic ultrafiltrates (and normal serum, for comparison) were fractionated by means of gel filtration. The collected fractions were further investigated by combined analytical techniques: "high-performance" liquid chromatography, gas chromatography, mass spectrometry, and isotachophoresis. Ultrafiltrate fractions in the so-called middle molecular mass region (Mr 500-2000) contained a considerable amount of substances of low molecular mass, such as carbohydrates, organic acids, amino acids, and ultraviolet absorbing solutes. Ultraviolet absorbance in the "middle molecular mass region" of the gel chromatogram is mainly due to the presence of these rather low-molecular-mass solutes. Therefore this signal is not a quantitative measure of molecules with a "middle" molecular mass.
Gas-chromatographic determination of ethylene glycol in serum.
Authors: Porter W H , Auansakul A 
Published: January 2020

Abstract
We describe a new gas-chromatographic procedure for ethylene glycol in serum, determined as the cyclic phenylboronate ester. The method is rapid, requires only 100 microL of serum, and either an OV-1 or an OV-17 column is used. The linear dynamic range extends to at least 5000 mg/L, with a lower limit of detection of 10 mg/L. Analytical recovery of ethylene glycol from serum averaged 97% (95-101%) over the concentration range of 250-5000 mg/L. The method demonstrates good precision, with CVs less than 2.5%, over the concentration range 500-2000 mg/L.