bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nephelometry of human IgG subclass concentration in serum.
Authors: Beck O E , Kaiser P E 
Published: January 2020

Abstract
An immunoassay method for determination of human IgG subclass concentration by rate nephelometry was developed by using the Beckman Immunochemistry Analyzer, subclass-specific antisera, and a human serum standard. Twelve sera derived from normal as well as gammapathological patients were analyzed. The total IgG concentration, as determined by using a readily available kit, correlated with the sum of the concentration of the individual subclasses. Most of the gammapathological cases were shown to be the IgG1 subclass, which was confirmed by radial immunodiffusion.
Elimination of inhibitors of alkaline phosphatase from 2-amino-2-methyl-1-propanol.
Authors: Derks H J , Borrias-van Tongeren V , Terlingen J B , Koedam J C 
Published: January 2020

Abstract
When 2-amino-2-methyl-1-propanol buffer solutions are extracted with chloroform, impurities inhibiting alkaline phosphatase are selectively removed and this source of variation is thereby greatly decreased. We also studied the effect of adding zinc sulfate to this buffer. A combination of chloroform extraction and zinc sulfate, added to give concentrations from 5 to 10 mumol/L, results in buffer of high and consistent quality. The alkaline phosphatase activities of 12 reference sera of different origin were determined with use of the purified buffers. Those sera, which closely resembled human serum in terms of alkaline phosphatase isoenzyme composition, behaved similarly to human serum. Use of such control sera is strongly recommended.
Absence of beta-globulin band in the serum protein electropherogram of a patient with liver disease.
Authors: Vladutiu A O , Kim J S 
Published: January 2020

Abstract
Agarose-gel electrophoresis of serum of a 72-year-old woman with liver cirrhosis showed virtually no beta-globulins two weeks before the patient's death. There was marked decrease in the concentrations of transferrin, beta-lipoproteins, hemopexin, complement component C3, beta-glycoprotein I, and cholesterol in serum. Absence of a beta-globulin band appears to signify an ominous prognosis.
New approach to cystic fibrosis diagnosis by use of an improved sweat-induction/collection system and osmometry.
Authors: Webster H L , Barlow W K 
Published: January 2020

Abstract
A comprehensive equipment system is described that induces, collects, and analyzes sweat as a diagnostic procedure for cystic fibrosis. The safety and convenience of the iontophoretic induction phase have been improved by specially designed circuitry and electrodes. The problem of potentially serious error as a result of condensation within sweat-collection cups has been eliminated by use of a thermostatically controlled heated cup. The osmolality of the collected sweat is measured with a vapor-pressure osmometer. Data are presented to support the validity of osmolality as an alternative to electrolyte assay or electrical conductivity measurement and normal and abnormal ranges are provided. The complete system was tested in a pediatric hospital and data are presented to illustrate the relative advantages of the system with respect to safety, convenience, diagnostic reliability, and decreased potential for human error.
Improved determination of D-glucaric acid in urine.
Authors: Jung K , Scholz D , Schreiber G 
Published: January 2020

Abstract
Using a simplex optimization procedure, we have elaborated a sensitive and reliable micromethod for determining D-glucaric acid, based on inhibition of glucuronidase activity by 1,4-D-glucarolactone, produced from D-glucaric acid by heating. The maximum attainable difference between glucuronidase activity in the reaction mixture with and without D-glucaric acid was used as an optimization criterion. From the optimization scheme, 1 mmol/L 4-nitrophenyl-beta-D-glucuronide and pH 5.0 were found to be optimal conditions for determination of D-glucaric acid with this test. In contrast to other similar methods, in which a logarithmic calibration curve is used, we calculate D-glucaric acid with a linear calibration curve by using the Dixon (Biochem. J. 55: 170, 1953) plot. The coefficient of variation for the method (within-run and between-day precision) was from 3.1 to 5.8%. Men excrete more D-glucaric acid than do women per 24 hours, but we saw no sex-related differences in excretion of D-glucaric acid when it was expressed in terms of urinary creatinine.
A modified radioimmunoassay for 1,25-dihydroxycholecalciferol.
Authors: Gray T K , McAdoo T , Pool D , Lester G E , Williams M E , Jones G 
Published: January 2020

Abstract
A radioimmunoassay for 1,25-dihydroxycholecalciferol which did not cross react with 1,25-dihydroxyergocalciferol is described. IgG fractions were prepared from the serum of rabbits that had been immunized with 1,25-dihydroxycholecalciferol-3-hemisuccinate coupled to bovine albumin. Radioligand binding by the IgG fractions was time-, temperature-, and pH-dependent. The IgG fractions had a high affinity for 1,25-dihydroxycholecalciferol but cross reacted with 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol. Vitamin D2 metabolites did not cross react in the assay when amounts up to 9 ng per tube were tested. The determination of 1,25-dihydroxycholecalciferol in human serum required an organic extraction and chromatographic isolation of the metabolite. Radioligand binding was influenced by the presence and concentration of the proteins in the phosphate buffer. The mean concentration of 1,25-dihydroxycholecalciferol in serum from normal adults was 56 (SEM 5.7) ng/L. 1,25-Dihydroxycholecalciferol was not detectable in serum from a nephrectomized subject and the concentration in serum was lower than normal in hypoparathyroid patients. Ingestion of 1,25-dihydroxycholecalciferol by nephrectomized or hypoparathyroid patients restored the concentration of 1,25-dihydroxycholecalciferol in serum to the normal range. The stability of the IgG fraction, the relatively short incubation interval, and the ability to measure 1,25-dihydroxycholecalciferol without interference from 1,25-dihydroxyergocalciferol are unique aspects of this radioimmunoassay.
Colorimetric determination of serum 5'-nucleotidase without deproteinization.
Authors: Wood R J , Williams D G 
Published: January 2020

Abstract
We present a sensitive colorimetric determination of 5'-nucleotidase based on the measurement of liberated phosphate by reaction with stannous chloride/molybdenum blue. No protein precipitation is required. The method is simple, sensitive, economical, and easy to use, and involves relatively stable reagents.
Measurement of hemoglobin A1 by liquid chromatography and by agar gel electrophoresis compared.
Authors: Hayes E J , Gleason R E , Soeldner J S , Wacks M , Blankstein L 
Published: January 2020

Abstract
We compare measurement of total fast hemoglobin (HbA1) by "high-performance" liquid chromatography and by electrophoresis on agar gel. Blood samples were obtained from a diverse population (n = 222): offspring of two diabetic parents, diabetic patients with and without retinopathy, diabetic and non-diabetic pregnant women, patients in the coronary-care unit, and normal persons. Precision studies with a normal and an above-normal A1 sample resulted in overall CVs of 9.0% and 4.6% for the electrophoretic method and 4.4% and 2% for the chromatographic method. Linear regression analysis of values for total fast hemoglobin for the complete sample population and for each subgroup showed results of the electrophoretic method to be in excellent agreement with those by the chromatographic method. We conclude that the agar gel electrophoretic method offers a reproducible means for HbA1 determination that is comparable to the HPLC method in terms of accuracy and is highly suited for routine laboratory use.
Extended clinical trial and evaluation of urea nitrogen determination with the Ektachem GLU/BUN analyzer.
Authors: Bandi Z L , Fuller J B , Bee D E , James G P 
Published: January 2020

Abstract
We followed the "abbreviated precision protocol" of the National Committee for Clinical Laboratory Standards for the evaluation of precision, accuracy, and carryover in analysis for urea nitrogen with the multilayer film analysis system ("Ektachem"). We analyzed 456 clinical samples with this instrument, by the manual urease/glucose dehydrogenase method, and with the Beckman System I GLU/BUN Analyzer. Precision and accuracy were estimated for 50, 220, 270, and 500 mg/L urea nitrogen concentrations in 100, 30, or 20 microL of serum. Potential interference of 15 compounds was evaluated. Random error (defined as 1.965 X SD) was 7, 10, 12, and 18 mg/L. Systematic error was 3, 4, 5, and 15 mg/L. Total analytical error was 11, 14, 17, and 34 mg/L for analysis of 100 microL of serum at the above-stated urea nitrogen concentrations. The greatest interference (6 mg/L) was caused by ethanol (300 mg/L) and by hemoglobin (500 mg/L) in the urea nitrogen (at 260 mg/L) determination. Urea nitrogen concentration, as determined with the Ektachem was linearly related to the expected concentration, at least up to 1187 mg/L. Carryover was not statistically significant.
Screening for the Tay-Sachs carrier: a compromise program.
Authors: Potter J L , Robinson H B 
Published: January 2020

Abstract
A modified program designed to screen for the Tay-Sachs carrier is presented in which testing is limited to one or both partners, as needed, in an Ashkenazi Jewish (Jews of central and eastern Europe ancestry) mating when there is a definite commitment toward having a child, or in the early stages of the pregnancy. Testing of unmarried individuals is discouraged. The approach maximizes individualization of both the medical and laboratory aspects of the program and promotes a positive and beneficial relationship between physician and clinical chemist. There is little involvement of the lay population or clergy, and no special sources of funding are required. Whereas most mass screening programs for the Tay-Sachs carrier have attempted to educate large numbers of the lay public to bring pressure upon the medical community, we have reversed this approach and taken the much easier course of educating small numbers of physicians to better care for their patients. The program has been used successfully in a moderate-size city in which communication lines between laboratory and physician are easily established.
Quantitative determination of apolipoproteins C-I and C-II in human plasma by separate electroimmunoassays.
Authors: Curry M D , McConathy W J , Fesmire J D , Alaupovic P 
Published: January 2020

Abstract
Separate electroimmunoassays are described for measuring human plasma apolipoproteins C-I and C-II. Purified apolipoproteins C-I and CII were used in preparing monospecific antisera and as the primary standards. These assays are sensitive (maximal sensitivity, 20 ng), specific, rapid, precise (the within- and between-assay coefficients of variation for both assays were 5 and 8%, respectively), and accurate (accuracy was based on comparison of calculated and measured C-I, C-II, and C-III contents of an ApoC-containing column-eluent fraction) and are applicable to measurement of C-I and C-II polypeptides in whole plasma and density classes. However, plasma samples with triglyceride (triacylglycerol) concentrations greater than 6000 mg/L must be delipidized before analysis for C-II, as must those with greater than 12 000 mg/L before analysis for C-I polypeptide. Mean concentrations (and SD) of C-I in plasma of normolipidemic subjects and hyperlipoproteinemic phenotypes IIa, IIb, IV, and V were 60 (15), 70 (20), 100 (20), 100 (20), and 260 (94) mg/L, respectively. The corresponding C-II values were 40 (20), 43 (20), 68 (20), 65 (20), and 210 (70), respectively. C-I and C-II concentrations in patients with phenotypes IIb v, IV, or V significantly (p less than 0.001) exceeded those in normal persons or phenotype IIa. The observed correlations (r = 0.92 and r = 0.94) between triglyceride and C-I and C-II values suggest that these two polypeptides, like C-III, are excellent plasma markers for assessing the state of triglyceride metabolism.
Characterization of amylases produced by tumors.
Authors: Takeuchi T , Fujiki H , Kameya T 
Published: January 2020

Abstract
Amylases were purified and characterized from three amylase-producing human tumors. The relative molecular mass of the amylases was estimated to be 54 000 on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, different from human salivary amylase (61 000 and 64 000) and human pancreatic amylase (60 000). The tumor amylases had completely identical antigenicities with human salivary and pancreatic amylases against antibody to human salivary amylase, while the intensity of the tumor amylases was less than 20% of that of human salivary and pancreatic amylases on single radial immunodiffusion. On isoelectric focusing, two of the three tumor amylases showed a major peak at pH 6.4, which corresponded to a major peak of human salivary amylase, the other showed a major peak at pH 6.4, which corresponded to a minor peak of human salivary amylase. The three tumor amylases showed similar amino acid composition, different from those of human salivary and pancreatic amylases. These findings suggest that tumor amylases have a tertiary structure similar to that of normal human amylases, but differ from them in amino acid composition.
Determination of Cu, Mn, Fe, and Ca in six regions of normal human brain, by atomic absorption spectroscopy.
Authors: Goldberg W J , Allen N 
Published: January 2020

Abstract
A method is reported for measuring copper, manganese, iron, and calcium in brain tissue. We solubilized 100-mg samples of brain tissue with Soluene-350 and diluted the mixtures with methyl isobutyl ketone. Copper and manganese concentrations were measured by using a carbon rod atomizer, iron and calcium concentrations by using an air/acetylene and nitrous oxide/acetylene flame, respectively. The basal ganglia (caudate, putamen, globus pallidus, and substantia nigra) contained high concentrations of iron (10 to 19 mumol/g dry wt) as compared to concentrations found in the cortex (4 mumol/g) or the hippocampus (2.8 mumol/g). Copper exhibited a similar distribution pattern among the regions studied; 526 to 1140 mumol/g (dry wt) in the basal ganglia vs 496 mumol/g in the cortex and 426 mumol/g in the hippocampus. Manganese and calcium were uniformly distributed in the regions examined.
125I radioimmunoassay of delta-9-tetrahydrocannabinol in blood and plasma with a solid-phase second-antibody separation method.
Authors: Owens S M , McBay A J , Reisner H M , Perez-Reyes M 
Published: January 2020

Abstract
In this sensitive and specific radioimmunoassay for delta-9-tetrahydrocannabinol, an iodinated tracer with high specific activity and a solid-phase separation are used. Within-run coefficients of variation for 5.0 and 30.0 microgram/L concentrations were 7.8 and 4.2% for plasma and 14 and 10.6% for hemolyzed blood specimens, respectively. Day-to-day coefficients of variations ranged from 7.3 to 13.6% (for 7.6 to 33.0 microgram/L concentrations) for plasma and 13.4 to 18.1% (3.0 to 52.1 microgram/L) for hemolyzed blood specimens. Data for time after start of smoking of a standard THC-containing cigarette vs the concentration of delta-9-tetrahydrocannabinol in the plasma were similar to those obtained by others. Positive plasma specimens from the smoking study were analyzed by gas chromatography-mass spectrometry and by our radioimmunoassay. Nonparametric statistical comparison and linear regression (r2 = 0.972) showed that results by the two methods of analysis correlate well. The sensitivity of the assay was at least 0.3 microgram/L for plasma, 1.1 microgram/L for hemolyzed blood.
Modified heparin-Sepharose procedure for determination of plasma lipolytic activities of normolipidemic and hyperlipidemic subjects after injection of heparin.
Authors: Wang C S , Bass H B , Downs D , Whitmer R K 
Published: January 2020

Abstract
A modified heparin-Sepharose affinity chromatography procedure (Boberg et al., J. Lipid Res. 18:544-547, 1977) was developed to determine two different triglyceride lipase activities in human post-heparin plasma: hepatic triglyceride lipase (I) and lipoprotein lipase (II). With this procedure, lipoproteins were separated from the eluted lipases. The total lipolytic activity of II was eluted from heparin-Sepharose by heparin. The use of heparin as eluting agent prevents the partial inhibition of II, in contrast to the procedure based on elution of II with a high concentration of NaCl. In a comparative study with the modified heparin-Sepharose affinity column chromatography, the immunochemical and protamine sulfate inhibition procedures, the results indicated that these three procedures are equally suitable for the determination of I and II from normolipidemic subjects. However, because of possible interference by plasma, the column-chromatographic procedure is the preferred method for measuring lipase concentrations in post-heparin plasma of hyperlipidemic patients. The II activity of post-heparin plasma from normolipidemic subjects was not significantly age-(20-39 and 40-60 years) or sex-related. I activity was also not significantly different with respect to age, but was significantly greater in men than in women.
Use of a dried blood spot in immunoreactive-trypsin assay for detection of cystic fibrosis in infants.
Authors: Kirby L T , Applegarth D A , Davidson A G , Wong L T , Hardwick D F 
Published: January 2020

Abstract
We assayed more than 5000 blood spots dried on filter paper and approximately 1000 serum samples for immunoreactive trypsin, with commercial reagents (Behring and Sorin). The assay procedures were modified so that newborn screening is technically feasible. Both kits are satisfactory for serum assay, but the Sorin materials are better adapted for blood spot analysis. Immunoreactive trypsin in blood spots rapidly decreases with specimen age, but is stable in frozen serum. Values for premature infants do not differ significantly from those for full-term babies. Children with cystic fibrosis were readily distinguished from those without, up to at least one year of age.
Radioimmunoassay for pteroylglutamic acid.
Authors: Hendel J 
Published: January 2020

Abstract
I describe a radioimmunoassay for specific determination of pteroylglutamate in plasma, erythrocytes, and urine. Antiserum was raised in rabbits immunized with a conjugate of pteroylglutamic acid and methylated bovine serum albumin. The lowest detection limit of the assay was 0.1 microgram/L; the coefficient of variation ranged from 4.01 to 14.63%. No significant interference was demonstrated from tetrahydrofolic acid, 5-methyl-tetrahydrofolic acid, or methotrexate. Under normal sampling and storing conditions dihydrofolic acid was oxidized to pteroylglutamic acid and estimated as such in the assay. The clinical applicability of the assay is demonstrated by measurements of pteroylglutamate absorption rates after oral doses of pteroylglutamic acid or pteroyltriglutamic acid and by the estimation of the accumulation of pteroylglutamate and dihydrofolate in plasma during therapy with methotrexate.
The 16-hour-standing test and lipoprotein electrophoresis compared for detection of chylomicrons in plasma.
Authors: McNeely S , Seatter K , Yuhaniak J , Kashyap M L 
Published: January 2020

Abstract
We compared the 16-hour-standing plasma test to lipoprotein electrophoresis on agarose gel for detection of chylomicrons in 129 patients' samples with triglyceride values greater than or equal to 4.00 g/L. Chylomicrons were observed in 12 samples (9.3%) by use of the standing-plasma test and in 58 samples (45.0%) by use of agarose-gel electrophoresis. Thus the standing-plasma test did not detect chylomicrons in 46 samples where they were observed by electrophoresis, or 79.3% of all cases where chylomicrons were present. Chylomicronemia was missed in the presence of lower triglyceride concentrations as well as at very high ones. We recommend that lipoprotein electrophoresis be routinely performed on plasma of patients with triglycerides concentrations greater than 4.00 g/L to distinguish between types IV and V hyperlipoproteinemia, as well as to detect failure of a patient to fast before sample collection.
Cryoprotected Lactobacillus casei: an approach to standardization of microbiological assay of folic acid in serum.
Authors: Grossowicz N , Waxman S , Schreiber C 
Published: January 2020

Abstract
Folate-depleted, cryoprotected preparations of Lactobacillus casei are stable for at least eight months at -18 degrees C, capable of reproducible growth and suitable as a ready source of inoculum for measurement of folates in physiological fluids. Cryoprotected microorganisms can be a commercially available laboratory reagent, thus simplifying and further standardizing the microbiological assay of various nutriments. Standard folate growth curves of cryoprotected L. casei, prepared at intervals over eight months, are superimposable, have a low blank, and should eliminate the variations encountered with the continuous passages of microorganisms required for the classic microbiological assays. Serum folate values obtained by use of the cryoprotected L. casei fall into the same diagnostic groups as determined by the classic microbiological assay.
Automated Jendrassik-Grof method for measurement of bilirubin in serum with the Greiner Selective Analyzer (GSA II D), and comparison with the method involving diazotized 2,4-dichloroaniline.
Authors: Cherian A G , Soldin S J , Hill J G 
Published: January 2020

Abstract
We automated the Jendrassik-Grof method for measurement of bilirubin with the Greiner Selective Analyzer GSA II D. Comparison with the manual Jendrassik-Grof method showed a highly significant correlation coefficient of 0.994 for total and 0.980 for "direct" bilirubin measurement. The automated method showed good precision and was linear to 667 mu mol/L, the highest concentration tested. Addition of hemolysate caused a greater effect on the measurement of direct bilirubin than on total bilirubin. The inhibitory effect on measurement of total bilirubin, though small, was statistically significant at hemoglobin concentrations greater than 2 g/L. Comparison with the method involving diazotized 2,4-dichloroaniline showed the Jendrassik-Grof method to be relatively less affected by hemolysis and turbidity in the measurement of total bilirubin.