bluuebunny/crossref_metadata_2025 huggingface dataset:
Rendering the "poppy-seed defense" defenseless: identification of 6-monoacetylmorphine in urine by gas chromatography/mass spectroscopy.
Authors: Mulé S J , Casella G A
Published: January 2020

We report a sensitive, rapid, quantitative gas chromatographic/mass spectroscopic method for measuring the 6-monoacetylmorphine (6-MAM) metabolite of heroin in 0.5 mL of human urine. After a simple liquid-liquid extraction and derivatization, the trimethylsilyl derivative of 6-MAM is identified from its retention time (total ion current) and by selected ion monitoring. The limit of detection was 10 micrograms/L, corresponding to 0.2 ng of trimethylsilyl-6-MAM injected into the gas chromatograph/mass spectrometer. The presence of 6-MAM in urine is indicative of heroin. 6-MAM is not present in poppy seeds or in urine after the ingestion of products containing poppy seed.
Reference values for nucleosides and nucleobases in cerebrospinal fluid of children.
Authors: Gerrits G P , Haagen A A , De Abreu R A , Monnens L A , Gabreëls F J , Trijbels F J , Theeuwes A L , van Baal J M
Published: January 2020

Disturbances in the metabolism of purines and pyrimidines in neurologically affected patients can be reflected by aberrant concentrations of nucleosides and nucleobases in cerebrospinal fluid (CSF). However, normal values, especially for children at different ages, are lacking. We collected 1000 specimens of CSF from subjects ranging in age from newborn to 18 years, who were undergoing a diagnostic lumbar puncture for several clinical indications. Of these, 78 samples could be used retrospectively as a reference according to our criteria. The analyses were performed with a modified HPLC procedure. None of the substances shows age-dependency except uridine and uric acid. Uridine increases with age, and uric acid increases with age in boys older than 12 years.
Chemistry profiles in "wellness programs": test selection and participant outcomes.
Authors: Witte D L , Angstadt D S , Schweitzer J K
Published: January 2020

Insurers, employers, and individuals create demands for laboratory testing in "wellness programs." Tests chosen to identify cases deserving intervention included routine automated chemical tests plus high-density lipoprotein cholesterol, ferritin, and thyroid tests. Participants' unwarranted concerns were addressed with a personalized reporting schema. We tested 1338 individuals, identified 224 (16.7%) with significant abnormalities, and made phone contact follow-up with 193 (86%) of these six to 14 months later. Cholesterol results suggesting increased risk of heart disease were frequent, and were not studied. Interventions were initiated in 55 of the 193 followup cases (49 by physician and six by participants), including prescription of iron or thyroid hormone, counseling on dietary or alcohol intake, and repeat testing. For 58, there was medical advice without intervention; abnormal results were ignored by 79. Noteworthy participant anxiety was manifested in two of the 193 cases, both of whom were treated with iron. We conclude that 4% of the original 1338 participants potentially benefitted from intervention. Ferritin and thyroid tests initiated 33 (61%) of these 55 specific therapeutic interventions.
Accumulation of glycolic acid and glyoxylic acid in serum in cases of transient hyperglycinemia after transurethral surgery.
Authors: Perier C , Frey J , Auboyer C , Richard A , Aulagnier G , Heritier P , Gilloz A
Published: January 2020

Experimental data are presented here proving the accumulation of glycine in serum after transurethral prostatectomy and increased production of glycine metabolites: serine, alanine, glyoxylic acid, and glycolic acid. The presence of the metabolites glyoxylic acid and glycolic acid was demonstrated by gas-liquid chromatography and mass spectrometry. Glycine, glyoxylic acid, and glycolic acid possess neurological activity, so we examined the pathophysiology of the transurethral prostatectomy syndrome in view of the transient accumulation of these compounds in serum.
The potency of immunoglobulin G fragments for inhibition of interference caused by anti-immunoglobulin antibodies in a monoclonal immunoradiometric assay for thyrotropin.
Authors: Csako G , Weintraub B D , Zweig M H
Published: January 2020

Heterophile antibodies in patients' serum may produce false increases in apparent analyte concentrations in "sandwich"-type immunoassays. Using three patients with endogenous anti-mouse IgG antibodies and a two-site mouse monoclonal assay for thyrotropin, we studied the ability of IgG fragments to block this positive interference. Mouse whole IgG and IgG Fc fragment blocked the interference virtually completely; IgG F(ab')2 and Fab fragments did not. Rat and horse immunoglobulin fragments gave variable results. We suggest that sandwich assays formulated with IgG Fab or F(ab')2 fragments may be less susceptible to positive interference by heterophile antibodies. Unlike sera from the three patients, simulated human specimens containing heterologous anti-IgG antibodies showed little or no selectivity in inhibition by IgG fragments, and therefore are not useful to study this phenomenon.
Influence of hypertension and antihypertensive drugs on the biological intra-individual variation of electrolytes and lipids in serum.
Authors: Hölzel W G
Published: January 2020

Biological intra-individual CVs for Na+, Cl-, K+, calcium, cholesterol, high-density lipoprotein cholesterol, triglycerides in serum, and hemoglobin in blood were estimated in men with essential hypertension (EH) treated with beta-blockers and diuretics, and compared with those of normotensive men. Although in EH the mean concentrations of Na+, Cl-, K+, hemoglobin, and triglycerides were increased and that of HDL cholesterol was decreased, the average intra-individual CVs did not significantly differ between the two groups. The mean concentration of cholesterol, as well as the average intra-individual CV for it, was significantly higher in EH. There was no correlation between the intra-individual CVs for the analytes and the mean blood pressure of the individuals. Individual values were normally distributed for all analytes. There was no increase of the intra-individual CV with the lapse of time between consecutively measured values. The estimated average biological intra-individual CV was used to derive decision-making criteria for interpretation of test results observed in monitoring EH.
Total creatine kinase (CK) and CK-B activity in maternal blood and cord-blood samples after vaginal and cesarean births.
Authors: Liras G , Diaz V , Alvarez C , Arenas J , Sanz R , Martinez V
Published: January 2020

We studied variations in the activity of total creatine kinase (CK; EC 2.7.3.2) and of CK-B in maternal and cord-blood samples, comparing data obtained for vaginal and cesarean births. CK-B activity was determined with an immunoinhibition assay. In all cases, there was a significant postpartum increase in total CK and in CK-B activity in maternal sera, whereas cord-blood samples showed no significant differences between activities in arterial and venous blood for either vaginal or cesarean births. Statistically significant differences were found in CK-B activity, but not in total CK, between cord-blood samples from vaginal births and those from cesareans.
Determination of oxalate concentration in blood.
Authors: Costello J , Landwehr D M
Published: January 2020

The methods used for determination of oxalate in blood are reviewed, and the advantages and disadvantages of the two basic approaches--direct methods and in vivo isotope-dilution techniques--are compared. Possible reasons for the previous discrepancies between direct and isotopic methods are discussed, as are the effects of protein binding, sample handling, and storage conditions on oxalate values in plasma. Necessary precautions for obtaining reproducible results are presented. We recommend and critically review several direct methods, and describe the application of a direct method for oxalate determination in some other biological fluids.
Survey of alpha-amylase activity and isoamylases in autopsy tissue.
Authors: Whitten R O , Chandler W L , Thomas M G , Clayson K J , Fine J S
Published: January 2020

We quantified total amylase and its isoenzymes in 22 different human tissues obtained at autopsy. Isoenzymes were separated by use of wheat-germ inhibition (WI) and electrophoresis on cellulose acetate (CA) and agarose (AG). Mean (+/- SD) total activity was highest in salivary glands (parotid 1710 +/- 897 U/g, submandibular 605 +/- 354 U/g), and pancreas (258 +/- 137 U/g). All other tissues contained 100- to 1000-fold less amylase. As assessed with WI, pancreas, jejunum, liver, placenta, testis, skeletal muscle, and spleen contained more than 90% pancreatic isoamylase. Salivary glands and thyroid contained more than 90% salivary isoamylase. All other tissues contained a mixture of the two isoenzymes. CA and AG often produced different results. For both CA and AG the most common pancreatic isoforms were P2 and S1. Salivary gland homogenates demonstrated a band migrating in the P3 position on CA. We conclude that both types of amylase isoenzymes can be found in tissues other than salivary gland and pancreas, but that their low total amylase concentrations diminish their clinical importance.
A competitive enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in serum and urine samples.
Authors: Phillips A , Rowell F J
Published: January 2020

In this solid-phase competitive enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in serum or urine, antiserum to human alpha 1-acid glycoprotein is incubated with solid-phase-bound alpha 1-acid glycoprotein in the presence of standard or sample. Incubation with second antibody labeled with alkaline phosphatase then follows, before development with substrate. Results obtained correlate well with a fluorescent assay involving the dye Auramine O (r = 0.953) and with radial immunodiffusion (r = 0.921). The present assay covers the range 0.2 to 5 mg/L and 16 samples take 2.5 h to complete. This assay is useful for measuring concentrations of alpha 1-acid glycoprotein in serum and also in urine, for which other assay methods are not sufficiently sensitive.
Analytical performance of three commercially available nephelometers compared for quantifying proteins in serum and cerebrospinal fluid.
Authors: Salden H J , Bas B M , Hermans I T , Janson P C
Published: January 2020

We investigated the analytical performance and imprecision of three commercially available nephelometers for the quantification of various proteins in pooled serum and cerebrospinal fluid. Albumin, transferrin, IgG, IgA, and IgM in serum were determined nephelometrically (BNA, Behring; Array, Beckman) and turbidimetrically (Cobas Bio, Hoffmann-La Roche). All these proteins in cerebrospinal fluid except transferrin were determined nephelometrically with all three systems. CVs and lower limits of detection were compared for all instruments, and stability of calibration curves was evaluated.
Screening urine before microscopy, by automated test-strip preselection: clinical evaluation of the improved Rapimat II/T (Behring).
Authors: Kutter D , Braun C , Gallego F , Stirn-Thoma S
Published: January 2020

In many laboratories, microscopy of urines is restricted to specimens selected on the basis of positive tests, mainly for protein, blood, nitrite, and leukocyte esterase. Here, we analyzed several hundred specimens by use of multiple dipsticks, read in an improved reflectometer. By comparing the results with quantitative microscopy, it could be shown that this system allows selection, with acceptable sensitivity and specificity, of those specimens that are likely to contain clinically important microscopic elements.
An international quality-assessment program for measurement of aluminum in human plasma: a progress report.
Authors: Guillard O , Pineau A , Baruthio F , Arnaud J
Published: January 2020

In view of the increasing interest in measurement of aluminum in plasma of hemodialysis patients and the analytical difficulties, which may lead to false clinical interpretations, we organized an international interlaboratory quality-control program that has operated since 1983. The results obtained after four years (72 participants) demonstrate a lessened discrepancy of the results. This program allowed some laboratories to improve their results and even to solve some of their analytical problems. This surveillance will be continued and extended to include the analysis of dialysis fluids.
Interlaboratory proficiency survey of cholesterol and high-density lipoprotein cholesterol measurement.
Authors: McMillan T A , Warnick G R
Published: January 2020

We conducted a proficiency survey of cholesterol and high-density lipoprotein (HDL) cholesterol analysis in local clinical laboratories to determine whether increased national emphasis on cholesterol measurement had resulted in changes in performance from previous surveys. Sets of frozen aliquots of plasma and HDL supernate pools were sent to nine laboratories for analysis; results were compared with Northwest Lipid Research Center values, and relationships were determined by linear regression. Of all the cholesterol measurements, 81% were considered acceptable (i.e., within 9% of the NWLRC value), and 61% of the HDL cholesterol measurements were considered acceptable (within 50 mg/L of NWLRC values). These data represented no improvement over previous surveys. Workload had increased significantly: 79% for cholesterol and 284% for HDL cholesterol. On a bias plot, six of the laboratories demonstrated inaccuracy greater than the +/- 3% recommendation within the critical range of 2000-2400 mg/L for total cholesterol. For HDL cholesterol, two laboratories demonstrated bias greater than 10% at the critical point of 350 mg/L, with three additional laboratories displaying strong bias outside the decision point. The survey results indicate that apparently further improvements must be made for laboratories to achieve acceptable performance in cholesterol analysis.
Wheat-germ agglutinin method for measuring bone and liver isoenzymes of alkaline phosphatase assessed in postmenopausal osteoporosis.
Authors: Sørensen S
Published: January 2020

In the method of Rosalki and Foo (Clin Chem 1984;30:1182-6) bone and liver isoenzymes of alkaline phosphatase (EC 3.1.3.1) are quantified by using wheat-germ agglutinin (WGA). I suggest standardizing the procedure by using a WGA concentration that precipitates half of the alkaline phosphatase activity of serum pooled from an equal number of healthy women and men. By applying knowledge of the precipitation pattern in serum samples containing predominantly or exclusively bone or liver sources of alkaline phosphatase, I obtained results for the isoenzymes in healthy subjects that agreed with those by the heat-inactivation methods, as reported earlier in the literature. I then assessed the utility of the standardized procedure in a clinical study of prevention of postmenopausal bone loss. In patients receiving hormone replacement therapy, which is known to decrease bone turnover, the decrease in total alkaline phosphatase activity in serum was entirely ascribable to decreases in the bone isoenzyme activity, probably reflecting reduced bone formation, whereas the activity concentration of liver alkaline phosphatase remained unchanged.
High-density lipoprotein apolipoproteins in urine: II. Enzyme-linked immunoassay of apolipoprotein A-I.
Authors: Gomo Z A , Henderson L O
Published: January 2020

We have developed a capture antibody, noncompetitive, enzyme-linked immunoassay for urinary apolipoprotein A-I (Apo A-I) in urine, with use of affinity-purified polyclonal antisera against Apo A-I. A 96-well microtiter plate format is used, with unconcentrated urine as sample and dilutions of serum or high-density lipoprotein (HDL) as standards. The intra- and interassay variation (CV) averaged 7.4% and 9.4%, respectively. The limit of detection is low (1.25 ng/L), and no cross-reactivity with Apo B, C, E, or A-II was detected. The mean (+/- SD) concentrations of Apo A-I in urine of patients with glomerular proteinuria were a thousandfold greater (38.4 +/- 23.1 mg/L) than in normal subjects (16.3 +/- 11.3 micrograms/L in men, 17.97 +/- 7.7 micrograms/L in women, a significant difference, P less than 0.001). Apo A-I measurements correlated very well (r = 0.92) with selectivity index assessment. The diurnal variation of the concentration of Apo A-I in urine appears to result from dilution related to fluid intake. This enzymatic method is easy to perform, can be used with large numbers of samples, and is adaptable for use in the routine clinical laboratory. The method holds promise for discriminating between normal and subclinical kidney disease populations by measuring the concentrations of urinary Apo A-I excreted on HDL particles.
Plasma amino acid pattern of patients with HIV infection.
Authors: Ollenschläger G , Jansen S , Schindler J , Rasokat H , Schrappe-Bächer M , Roth E
Published: January 2020

We measured the free amino acids in plasma of 58 patients with HIV infection and in six persons in the risk group. The HIV+ patients had significantly increased concentrations of arginine, phenylalanine, and glutamate in comparison with both age- and sex-matched controls and the members of the risk group. Glutamate concentrations increased only in an advanced stage of the disease (WR 5 and 6 of the Walter Reed staging classification), whereas arginine and phenylalanine increased independently of the stage. There was no correlation between the amino acid concentrations and the number of T4 and T8 lymphocytes, the sedimentation rate, and the existence or absence of Kaposi's sarcoma. The amino acid pattern of HIV-infected persons is similar to that of cancer patients or those with other immune deficiencies.
A fluorescence polarization immunoassay evaluated for quantifying astromicin, a new aminoglycoside antibiotic.
Authors: Uematsu T , Sato R , Mizuno A , Nishimoto M , Nagashima S , Nakashima M
Published: January 2020

We evaluated a fluorescence polarization immunoassay (FPIA) procedure for measuring astromicin, a new aminoglycoside antibiotic. The calibration curve can be stored for at least 32 days without loss of accuracy. There were no interferences from hemoglobin (up to 4000 mg/L) or bilirubin (up to 200 mg/L), nor were there any cross-reactivities with amikacin, gentamicin, or tobramycin. Within-run precision (CV) for 20 replicates, each at concentrations of 5, 15, and 25 mg/L, was 1.25-2.11%. Between-run precision for these same concentrations, measured on five occasions, was 2.13-2.74%. Linear-regression analyses of data by FPIA (y) and HPLC (x) for plasma obtained from six healthy male volunteers who were given 200 mg of astromicin by 30-min intravenous infusion and for sera prepared by adding arbitrary amounts of astromicin showed highly significant correlations: r = 0.996 (n = 66), y = 0.96x - 0.48 mg/L and r = 0.981 (n = 59), y = 0.96x - 0.25 mg/L, respectively. This assay offers a rapid, efficient, and accurate system for therapeutic monitoring of astromicin in blood.
Glycated lysine increases in serum samples stored at -20 degrees C.
Authors: Schäffer L
Published: January 2020

The glycated lysine in serum protein was determined by HPLC measurement of furosine in hydrolyzed serum, with synthetic N alpha-Boc-N epsilon-(1-deoxy-D-fructosyl)-L-lysine as the standard. The glycated lysine value increased with time of storage when the serum was kept at -20 degrees C, possibly because of an ongoing reaction between glucose and the epsilon-amino groups of lysine in the frozen serum. The problem was eliminated by using storage at -70 degrees C or by acidifying the serum before storing it at -20 degrees C.
Fluorimetry of selenium in body fluids after digestion with nitric acid, magnesium nitrate hexahydrate, and hydrochloric acid.
Authors: Pettersson J , Hansson L , Ornemark U , Olin A
Published: January 2020

A digestion procedure involving nitric acid, magnesium nitrate hexahydrate, and hydrochloric acid suffices for selenium determinations in whole blood, serum, and urine by molecular fluorescence spectrometry. To test the accuracy of the method we compared the results with those from hydride-generation atomic absorption spectrometry, and we also analyzed reference materials.
Pancreatic amylase measured in serum by use of a monoclonal antibody immunochemically immobilized to a solid phase.
Authors: Mifflin T E , Hamilton M , Hubbard E , Kline M J , Bruns D E
Published: January 2020

We studied a method for measuring the pancreatic isoenzyme of amylase (EC 3.2.1.1) by use of a mouse monoclonal antibody against human salivary-type amylase (Clin Chem 1985;31:1283) coupled indirectly to particles of polyvinylidene fluoride via polyclonal goat anti-mouse immunoglobulin. These particles, in 200 microL of a suspension, could remove salivary amylase (activity 2200 U/L) from an equal volume of serum in 5 min. Measurement of amylase activity in the supernatant fluids from treated sera thus provided an assay of pancreatic amylase. Precision studies at three activity concentrations yielded within-run CVs of 1.6% to 1.7% (n = 25) and total CVs of 2.2% to 5.1% (20 days). Salivary amylase added to each of 10 sera was completely (99.8%, SD 1.6%) removed. The new method (y) showed the following regression statistics when compared with an electrophoretic method (x): slope = 0.989 (SD 0.019), intercept = -0.220% (SD 1.48%), SEE 4.0%, n = 51. Similar respective regression values were found for urine samples: slope = 0.934 (SD 0.053), intercept = 2.3 U/L (SD 3.2), SEE 8.4 U/L, n = 26. The following respective values were found when the new method (y) was compared with the previously described immunoprecipitation assay (x): slope = 1.02 (SD 0.02), intercept = 2.2% (SD 1.4%), SEE 3.3%, n = 23 sera. Reference intervals for pancreatic amylase activity in serum were established for three different substrates: maltotetraose, maltopentaose, and p-nitrophenylheptaoside.
Clinical and analytical evaluation of different methods for measurement of creatine kinase isoenzyme MB.
Authors: Schwartz J G , Brown R W , McMahan C A , Gage C L , Herber S A
Published: January 2020

We evaluated the clinical and analytical performance of the new immunochemiluminometric assay (ICMA; Ciba Corning) for measurement of creatine kinase isoenzyme MB (CK-MB), and compared it with three other methods: immunoradiometric assay (IRMA; International Immunoassay Labs); immunoinhibition assay (Seradyn); and an immunoinhibition/column method (Du Pont). Intra-test precision for all kits was good. We evaluated 32 patients' samples by all four methodologies. Only one of the four methods (aca, Du Pont) showed evidence of linearity. Efficiency in the diagnosis of myocardial injury in our study ranged from 53% (Seradyn) to 96% (Du Pont). We evaluated serial specimens from 20 separate patients by the IRMA and the ICMA to determine whether myocardial injury could be diagnosed earlier by the ICMA. In patients with acute myocardial infarction, the ICMA displayed positive values earlier and longer than the IRMA, suggesting that the ICMA is suited for screening for myocardial damage in hospitalized patients.
Effects of various serum proteins on quantification of fructosamine.
Authors: Rodriguez-Segade S , Lojo S , Camiña M F , Paz J M , Del Río R
Published: January 2020

We determined fructosamine concentrations with the CentrifiChem 600 centrifugal analyzer and the Hitachi 737 discrete analyzer. Reference intervals agreed with the most recently published results, and values in fasting patients were significantly correlated with glycated hemoglobin, plasma glucose, albumin, beta- and gamma-globulins, IgG, IgA, IgM, and total protein. Partial correlation analysis showed that only fructosamine and IgA were dependently related. In a group of nondiabetic patients with pathological values for IgA concentrations, 79.4% had pathological values for fructosamine. These results throw doubt on the clinical value of fructosamine determinations if serum IgA is not taken into account.
Differences between values for plasma and serum in tests performed in the Ektachem 700 XR Analyzer, and evaluation of "plasma separator tubes (PST)".
Authors: Doumas B T , Hause L L , Simuncak D M , Breitenfeld D
Published: January 2020

We measured 25 analytes in plasma and serum from the same blood specimen, using the Kodak Ektachem 700 XR Analyzer. For 22 of the analytes, values for plasma were practically the same as those for serum; for the other three, differences between concentrations in plasma and serum were significant, both statistically and medically. Values for the same analytes in plasma from regular heparinized tubes were essentially indistinguishable from those for plasma obtained by use of Plasma Separator Tubes (PST).
Alkaline phosphatase isoenzymes of liver and bone origin are incompletely resolved by wheat-germ-lectin affinity chromatography.
Authors: Gonchoroff D G , Branum E L , O'Brien J F
Published: January 2020

We used wheat-germ-lectin affinity chromatography as a tool to investigate the structure of alkaline phosphatase (ALP, EC 3.1.3.1) and to obtain fractions enriched in either bone or liver ALP activity. Liver and bone isoenzymes in serum samples were incompletely resolved except that the activity in the nonretained fraction (fraction 1) always represented pure liver isoenzyme and constituted a larger percentage of total activity in pooled sera with increased liver ALP activity than in pooled sera with increased bone activity. In contrast, a more avidly retained ALP activity, presumably with high glycosylation, was found in human serum with high activity of bone ALP. Using a solid-phase immunoassay, we examined the fractions obtained from the wheat-germ-lectin-Sepharose 4B column to determine whether the isoenzyme preference of the monoclonal antibody was markedly influenced by the degree of glycosylation. Whether samples contained high proportions of liver or of bone isoenzyme activity, the nonretained fraction contained a higher percentage of liver ALP, whereas the more strongly bound fraction contained a higher percentage of bone ALP. Except for eluted fractions that either contained no detectable N-acetylglucosamine or the highest percentage of it, the avidity of the liver-isoenzyme-specific monoclonal antibody for ALP seemed to be independent of the degree of glycosylation, suggesting that the epitope for monoclonal antibody may be expressed in some structure other than the carbohydrate moieties.
High-performance liquid-chromatographic analysis for serotonin and tryptamine excreted in urine after oral loading with L-tryptophan.
Authors: Tsuchiya H , Hayashi T , Tatsumi M , Hoshino Y , Ohtani S , Takagi N
Published: January 2020

We describe a method used for determining serotonin and tryptamine in urine after oral loading with their precursor amino acid. Several factors affecting prepurification and chromatographic separation of both indoleamines were optimized, including sample extraction and mobile-phase composition. Under optimal conditions, serotonin and tryptamine are extracted from urine samples together with an internal standard, and then they are separated by reversed-phase chromatography followed by native fluorescence detection. The analytical procedure is simple enough to apply to routine analysis and performable at low cost. Sensitivity and selectivity of the method are satisfactory enough to determine urinary serotonin and tryptamine. By pursuing urinary excretion of serotonin and tryptamine after oral loading with L-tryptophan (30 mg per kilogram body weight), our method proves that urinary excretion of both indoleamines increases immediately after loading and reaches a maximum in about 45 min.
Lp(a) lipoprotein concentration in serum of patients with heavy proteinuria of different origin.
Authors: Karádi I , Romics L , Pálos G , Domán J , Kaszás I , Hesz A , Kostner G M
Published: January 2020

We measured serum cholesterol, triglyceride, and lipoprotein Lp(a) concentrations in serum of 37 patients with massive proteinuria of different origin, comparing values with those for age- and sex-matched controls and finding significantly increased Lp(a) concentration in the total group of patients compared with controls. Lp(a) concentration was not correlated with serum cholesterol, triglyceride, serum creatinine, daily urinary protein loss, or selectivity index. Selecting the patients according to their histological diagnosis obtained by renal needle biopsy, we found divergent results in seven patients with minimal change disease (MCD) compared with 11 patients with membranoproliferative glomerulonephritis. Lp(a) in MCD patients did not differ from that controls (101 +/- 102 and 90 +/- 115 mg/L) and correlated positively with total daily urinary protein loss (r = 0.7962, P less than 0.05). In contrast, the patients with membranoproliferative glomerulonephritis had significantly higher Lp(a) values than the controls (219 +/- 222 mg/L), and Lp(a) concentrations correlated negatively with the daily protein loss in urine (r = -0.6545, P less than 0.05). The most surprising results were the marked Lp(a) concentrations in serum of three patients with primary amyloidosis and nephrosis syndrome. Our results indicate a regulatory role of the kidney in the metabolism of Lp(a) and different effects on the serum Lp(a) concentration, depending on the type of damage to renal tissue.
Calciferin and cathepsin D-like acid protease in serum in acute and chronic liver injuries in rats and humans.
Authors: Terayama H , Shimizu N , Fukuzumi R
Published: January 2020

Serum from patients with chronic liver diseases (chronic hepatitis, cirrhosis, and hepatomas) contained greater concentrations of calciferin (total 1.7-fold, free 3.3-fold) than that from normal subjects. There were also decreases in the concentration and affinity of the calciferin-binding protein(s) in the patients' sera, but the amount of cathepsin D (EC 3.4.23.5)-like acid protease (total and free) was within normal limits. In addition, rats with acute liver injuries (partial hepatectomy or CCl4 administration) showed increases in calciferin and acid protease in their serum. Rats subjected to continuous feeding of 3'-methyl-4-dimethylaminoazobenzene (a potent hepatocarcinogen) also showed an increase of both analytes in the earlier stages (two to eight weeks; acute phase). Later (13 weeks or more; chronic phase), however, only acid protease appeared to return to normal values.
Estrogen and progesterone receptor assays, by the EIA method (Abbott), of low-speed supernates of breast-cancer homogenates.
Authors: Hähnel R , Avenell M H , Hähnel E
Published: January 2020

Estrogen receptor (ER) and progesterone receptor (PR) assays were performed by solid-phase enzyme immunoassays (Abbott) on low-speed (2600 x g) and high-speed (100,000 x g) supernates of breast-cancer homogenates. The results were similar, indicating that ultracentrifugation is not essential for ER and PR assays with the Abbott kit.
Rate immunonephelometry and radial immunodiffusion compared for apolipoproteins AI and B assay.
Authors: Bachorik P S , Cloey T A
Published: January 2020

We measured apolipoproteins (apo) AI and B in fresh plasma samples and serum control pools by using two rate immunonephelometric assay (INA) methods (Beckman "Array" and Behring) and radial immunodiffusion (RID). Both INA methods on average gave apoAI values similar to those by RID in fresh plasma samples. The coefficients of correlation for the two INA-RID method pairs were as follows: Beckman INA vs RID, n = 94, r = 0.73; and Behring INA vs RID, n = 112, r = 0.66. The bias between the INA and RID methods was reflected reasonably well by either lyophilized or frozen control pools. For apoB, the Beckman INA measurements in fresh plasma averaged 40% lower than RID values, due almost entirely to the values assigned to calibration sera, but results by the two methods were highly correlated (n = 94, r = 0.93). The Behring INA values for fresh plasma averaged only 13% lower than RID values, but the two methods were less well correlated (n = 112, r = 0.74). Frozen control pools were most suitable for apoB analysis.
Changes in iron, zinc, and copper concentrations in serum and in their binding to transport proteins after cholecystectomy and cardiac surgery.
Authors: Fraser W D , Taggart D P , Fell G S , Lyon T D , Wheatley D , Garden O J , Shenkin A
Published: January 2020

Concentrations of iron, zinc, and copper and of their respective transport proteins transferrin, albumin, and ceruloplasmin were measured in serum after elective cholecystectomy and cardiac surgery. The pattern of changes in the concentrations of iron, zinc, and copper was reproducible, with an early increase in serum iron and zinc, then a decrease in the concentrations as these metals are dissociated from their serum transport proteins. Zinc and iron concentrations change before the increase in C-reactive protein, which begins 8 h after incision, whereas the copper concentration in the serum remains constant in the early postoperative period. Quantitative and kinetic differences were observed in both the trace metal and protein changes after cardiac surgery and cholecystectomy. These studies indicate the complexity of interpreting changes in trace elements in serum after surgery.
A sensitive method of screening for urinary porphobilinogen.
Authors: Buttery J E , Chamberlain B R , Beng C G
Published: January 2020

In this screening method for urinary porphobilinogen (PBG), urine is added to Dowex 2 resin under alkaline conditions in a test tube and mixed. The supernate is removed and the adsorbed PBG is eluted with acid and reacted with Ehrlich's reagent. We compared results with those by the Watson-Schwartz screening method, using urine samples from normal people with and without added PBG. At a PBG concentration of about five times the upper limit of normal, the resin method gave a sensitivity of 100%; the Watson-Schwartz method gave a sensitivity of 51%. At lower PBG concentrations of just over and twice the upper limit of normal, the sensitivity by the resin method was respectively 97% and 100%. With normal urine samples, the resin method gave negative results for all samples (100% specificity) and the Watson-Schwartz had 95% specificity. Our data indicate that the resin method is sensitive, specific, and reliable and is superior to the Watson-Schwartz method.
Effect of transport conditions on the stability of biochemical markers in blood.
Authors: Hankinson S E , London S J , Chute C G , Barbieri R L , Jones L , Kaplan L A , Sacks F M , Stampfer M J
Published: January 2020

We examined the stability of lipids, carotenoids, alpha-tocopherol, and endogenous hormones in plasma prepared from whole blood that had been mailed to a central location for processing. Initially, to simulate transport conditions, whole-blood samples were stored in the laboratory, either at room temperature or cooled, for up to 72 h before processing. In the latter samples, lipid concentrations changed up to 1.4% per day, carotenoids up to -5.5%, and hormones up to 9.5%. In a second study, analyte concentrations in plasma from cooled whole blood mailed via overnight courier were compared with those from plasma that had been immediately separated, frozen, and mailed via overnight courier. Concentrations of cholesterol, high-density lipoprotein subfraction 3, apolipoprotein B, and retinol were stable. Overall, for each marker except estradiol, the between-person variation was at least twice the within-person variation. In a third study, at least 340 micrograms of DNA was recovered from 30 mL of cool-shipped whole blood. Our results indicate that shipping whole-blood samples by overnight courier is feasible for assay of several biochemical markers of interest in epidemiological research.
Assessment of renal function by serum creatinine and creatinine clearance: glomerular filtration rate estimated by four procedures.
Authors: Van Lente F , Suit P
Published: January 2020

We compared creatinine concentrations in serum and urine and creatinine clearances determined by two Jaffé (Beckman's "Astra," Boehringer Mannheim Diagnostics) and two enzymatic (Kodak, Boehringer Mannheim Diagnostics) methods. Serum creatinine and creatinine clearances determined by each method were also compared with the glomerular filtration rate as measured with use of sodium [125I]iothalamate in patients with a wide range of renal function. Results between methods correlated excellently, but we saw clear method-dependent biases of up to 2.9 mg/L for serum. The highest serum creatinine values and the lowest creatinine clearances were obtained with Boehringer Mannheim Diagnostics' Jaffé method. The reciprocal of the serum creatinine and the creatinine clearance also correlated well with the glomerular filtration rate, but all methods over-estimated the glomerular filtration rates to varying degrees. Appropriate standardization of methods appears to be as important as method principle for establishing an accurate relationship between creatinine determinations and glomerular filtration rate.
Two-site immunochemiluminometric assay of intact human parathyrin in serum with use of a tracer peptide purified by reversed-phase high-performance liquid chromatography.
Authors: Böhler U , Blind E , Vogel G , Hitzler W , Flentje D , Schmidt-Gayk H
Published: January 2020

For this two-site immunochemiluminometric assay of intact human parathyrin (hPTH), the luminescent tracer was synthetic hPTH(53-84), conjugated via succinimide linkage to (aminobutyl)ethyl-isoluminol hemisuccinimide (abei-h). Purification of the labeled hPTH(53-84) by reversed-phase high-performance liquid chromatography allowed isolation of the conjugate having the highest incorporation of abei-h, 1.6 mol per mole of hPTH(53-84). The solid-phase antibody directed against the N-terminal part of hPTH was immobilized by adsorption onto the polystyrene surface of the assay tube and extracted the intact hPTH and N-terminal fragments. Another antibody against synthetic hPTH(53-84), which bound to the C-terminal part of intact hPTH, was indirectly labeled at its second free binding site with the abei-h-labeled hPTH(53-84). The assay has a detection limit of 0.5 pmol/L; it is accurate, precise, and reliable; and it shows a linear response for samples containing up to 100 pmol of hPTH per liter. The normal reference interval ranged from 1.8 to 5.9 pmol/L; 56 patients with primary hyperparathyroidism had concentrations ranging from 5.9 to 113 pmol/L. The concentrations detected in patients with idiopathic hypoparathyroidism were below the normal reference interval.
Alkaline phosphatase activity from human osteosarcoma cell line SaOS-2: an isoenzyme standard for quantifying skeletal alkaline phosphatase activity in serum.
Authors: Farley J R , Kyeyune-Nyombi E , Tarbaux N M , Hall S L , Strong D D
Published: January 2020

Earlier we described a kinetic assay for quantifying skeletal alkaline phosphatase (ALP) isoenzyme activity in serum. The precision of the assay depends on including ALP standards for the skeletal, hepatic, intestinal, and placental isoenzymes. We wondered whether human osteosarcoma cells could provide an efficient alternative to human bone or Pagetic serum as a source of the skeletal ALP standard. ALP activities prepared from five human osteosarcoma cell lines were compared with a bone-derived ALP standard with respect to heat stability and sensitivity to chemical effectors. Two of the cell lines (SaOS-2 and TE-85) contained ALP activities that resembled the bone-derived standard. We selected SaOS-2 cells for additional evaluation (as a potential source of isoenzyme standard), because they contained 40-50 times more ALP activity than did the TE-85 cells. To include the SaOS-2 cell-derived ALP activity in the quantitative isoenzyme assay, we diluted the enzyme in a solution containing heat-inactivated (i.e., ALP-negative) human serum. Surprisingly, this dilution caused a 60-125% increase in maximum enzyme activity. In the quantitative assay of ALP isoenzyme in serum, the SaOS-2 derived ALP was indistinguishable from the serum skeletal ALP standard, with respect to the above criteria and assay variations. Evidently ALP from SaOS-2 cells is suited as a standard for measuring skeletal ALP activity in this assay.
Strong association of a single nucleotide substitution in the 3'-untranslated region of the apolipoprotein-CIII gene with common hypertriglyceridemia in Arabs.
Authors: Taş S
Published: January 2020

A potential genetic marker for hypertriglyceridemia and coronary disease, an apolipoprotein-CIII gene allele displaying a single nucleotide substitution, was found in 71% of Arabs with primary hypertriglyceridemia. Over 96% of the unrelated adults possessing this allele showed hypertriglyceridemia. The same allele was found rarely among normotriglyceridemic subjects. In further support of involvement in hypertriglyceridemia, this allele was co-inherited with increased serum triglycerides in a three-generation family. Moreover, a gene dosage effect was also found. A mechanism of action for the allele is suggested by the findings that the subjects possessing the allele show markedly increased very-low-density lipoproteins, decreased high-density lipoproteins, and borderline chylomicronemia demonstrable by lipoprotein electrophoresis. Electrophoresis of the selectively amplified-restricted apolipoprotein-CIII DNA on agarose gel provides a rapid diagnostic test that allows identification of the subjects with this allele in less than a day.
Screening for microalbuminuria in patients with diabetes mellitus: frozen storage of urine samples decreases their albumin content.
Authors: Elving L D , Bakkeren J A , Jansen M J , de Kat Angelino C M , de Nobel E , van Munster P J
Published: January 2020

The influence of storage on urinary albumin concentration was prospectively studied with use of overnight urine specimens (Albustix negative) from 73 diabetic patients. From each urine sample four aliquots were taken. One was stored at 4 degrees C and assayed within two weeks, the other three were stored at -20 degrees C and assayed within two weeks and after two and six months. Albumin concentration was measured with laser immunonephelometry. The detection limit, 1 mg/L, suffices for the screening of diabetic patients for microalbuminuria. After storage for two and six months at -20 degrees C, significantly lower albumin concentrations were found. The difference was mainly caused by lower concentrations found in urine samples in which a precipitate had formed, which was the case in 22 and 25 samples, respectively. Thus, freezing of urine samples for determination of low concentrations of albumin may yield falsely low results. Urine samples are best stored at 4 degrees C and assayed within two weeks.
Proficiency testing in a medical-needs context.
Authors: Lott J A , Manning N R , Kyler M K
Published: January 2020

Proficiency testing by State and Federal agencies is an ongoing activity of clinical laboratories and an occasional source of anxiety; strict statistical evaluations of "snapshot" laboratory values are inappropriate and medical-needs criteria should be used. The quality of laboratory results largely depends on available technology. Fortunately, for most of the common clinical chemistry analytes there has been a steady reduction of imprecision during the past 20 years. Proficiency testing may have been the stimulus for this improved performance. Medical-needs criteria differ, depending on the testing goal. For proficiency testing, population screening criteria are appropriate, e.g., the College of American Pathologists fixed criteria for the common tests. Stricter criteria are needed for short-term (inpatient) and long-term (outpatient) monitoring of laboratory data. Explicit proficiency-testing limits are given here for nine of the common clinical chemistry tests for each of the three medical-needs criteria described above. The limits consider total error--i.e., bias from the believed correct value, and imprecision. Rather broad limits are acceptable for the commonly performed enzyme tests when used for screening purposes.
Rapid, reliable in vivo assays of human phosphate metabolites by nuclear magnetic resonance.
Authors: Bottomley P A , Hardy C J
Published: January 2020

This accurate, reliable, and fast method of assaying absolute concentrations of phosphate metabolites noninvasively in living tissue, including that of humans, combines 31P nuclear magnetic resonance (NMR) spectroscopy and 1H NMR imaging. The images are used to measure the areas of metabolite-bearing tissue in selected sections through the subject, and 31P spectra are acquired from the same section, together with a concentration reference located on the periphery. Metabolite concentrations are calculated from the ratios of areas and integrated signal intensities. Apparatus and protocol are designed to eliminate corrections due to magnetic field nonuniformities and NMR relaxation times. Mean (and SD) concentrations of adenosine triphosphate (ATP), phosphocreatine, and inorganic phosphate (Pi) measured in the brains of 15 normal adult human volunteers with a 1.5-T NMR system were 3.03 (0.49), 5.18 (0.89), and 1.5 (0.7) mmol per liter of wet tissue, respectively. Acquisition times of only a few minutes should facilitate metabolic studies of patients with disorders in limbs and brain, particularly those affecting entire organs.
Binding of labeled thyroxin analog to serum proteins evaluated after radioimmunoassay of free thyroxin.
Authors: Arevalo G
Published: January 2020

In ambulatory patients, assay of free thyroxin (FT4) in serum correlates well with thyroid status and with results obtained by equilibrium dialysis. The validity of FT4 results has been questioned mainly in euthyroid patients with altered concentrations of thyroid hormone-binding proteins, as in nonthyroidal illness, hereditary analbuminemia, familial dysalbuminemic hyperthyroxinemia (FDH), and the presence of iodothyronine-binding antibodies. I present here a study of the binding of [125I]T4-derivative to serum proteins in the supernate, which is ordinarily discarded after determination of FT4 by one-step radioimmunoassay with dextran-coated charcoal used to separate the free and bound fractions. The results are expressed as a ratio, with results for a normal serum pool as reference. The average ratio was high in hyperthyroid subjects, 1.26 (SD 0.12, n = 25), and in hypoalbuminemia, 1.20 (SD 0.10, n = 15), and low in FDH, 0.62 (SD 0.11, n = 9), and hypothyroid subjects, 0.90 (SD 0.06, n = 20). In normal individuals it was 0.98 (SD 0.05, n = 30). Determination of the analog-binding rate complements the FT4 result and allows for the recognition of cases with abnormal binding by serum proteins, without recourse to other tests recommended for thyroid-function studies.
Emetine identified in urine by HPLC, with fluorescence and ultraviolet/diode array detection, in a patient with cardiomyopathy.
Authors: Lachman M F , Romeo R , McComb R B
Published: January 2020

A 15-year-old girl with a four-month history of cardiac failure from undetermined cause was admitted to the hospital with weakness, fatigue, and weight loss. During her hospitalization she was found to have abused diet aids, laxatives, and cathartics. Although an electrocardiogram revealed nonspecific T-wave abnormalities and laboratory studies showed supranormal enzyme test results for creatine kinase and lactate dehydrogenase, no definite explanation of the cardiomyopathy was forthcoming. Ipecac abuse leading to cardiomyopathy was suspected early in the hospitalization. HPLC analysis of a urine sample showed emetine, a principle component of ipecac, the presence of which was later confirmed by more-specific HPLC analysis with photodiode array detection.