bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas-chromatographic measurement of 3-hydroxybutyrate and lactate in plasma and 3-hydroxybutyrate in whole blood.
Authors: Cosmi G , Di Corcia A , Samperi R , Vinci G 
Published: January 2020

Abstract
We describe two simple, rapid, and sensitive gas-chromatographic methods. One is for determining 3-hydroxybutyrate and lactate in plasma, the other for determining 3-hydroxybutyrate in perchloric acid extracts of blood. Samples are purified by adsorption onto graphitized carbon black (Carbopak B). After desorption, the two hydroxyacids are gas-chromatographically measured. Chromatography is on Carbopack B/polyethylene glycol (Mr 20 000)/trimesic acid, 94.4/ 4.8/0.8 by weight. A series of determinations of 3-hydroxybutyrate in whole blood from 15 subjects gave a mean of 59 (SD 46) mumol/L, with 97.8% analytical recovery (range 94.4-101.8%). In 15 plasma samples, we determined a mean value for 3-hydroxybutyrate of 62 (SD 72) mumol/L, with an analytical recovery of 96.4% (range 93.5-97.6%) and a mean value for lactate of 0.99 (SD 0.55) mmol/L, with an analytical recovery of 92.0 (range 91.3-97.6%). Six replicate analyses of plasma containing typical concentrations of lactate and 3-hydroxybutyrate gave respective CVs of 3.2, 2.1, 1.6, and 1.4%, and 4.9, 3.7, 2.8, and 2.0% for low, medium, high, and very high concentrations. Total analysis time for either method is less than 1 h.
Creatine kinase B subunit as measured with a radioimmunoassay kit in detection of acute myocardial infarction.
Authors: Witherspoon L R , Shuler S E , Genre C F , Gilbert S S , Moore R J , Meihaus V , Hurry E K 
Published: January 2020

Abstract
Results with a commercial radioimmunoassay (RIA) reagent kit for quantification of the creatine kinase B subunit (CK-B) (Nuclear-Medical Laboratories, Irving, TX 75061) were compared with results obtained by electrophoresis for patients consecutively admitted to our coronary care unit for suspected acute myocardial infarction. Analytical sensitivity, precision, and specificity of the RIA were satisfactory. Its clinical efficacy was assessed in 97 patients suspected of having had an acute myocardial infarction. Of 30 patients who had had an acute myocardial infarction, increased CK-B was detected by RIA in 30 and by electrophoresis in 27. The temporal relationship between CK-B by RIA and CK-MB by electrophoresis was similar. Of 66 admissions where infarction was not established, CK-B was negligibly increased in samples from four patients by RIA, and from one by electrophoresis. Although not abnormally increased (greater than 5 U/L), CK-MB was detected by electrophoresis in samples from another five of these 66 patients. We conclude that estimation of CK-B by this RIA is an excellent alternative to estimation of CK-MB by electrophoresis in patients suspected of having had an acute myocardial infarction.
Usefulness of serial determinations of myoglobin and creatine kinase in serum compared for assessment of acute myocardial infarction.
Authors: Cairns J A , Missirlis E , Walker W H 
Published: January 2020

Abstract
Twenty-one patients with their first myocardial infarction underwent serial blood sampling every 2 h for determination of serum creatine kinase (CK) and myoglobin during the first 48-72 h after onset of pain. The first blood sample, obtained at a mean time of 4.4 h after infarct onset, invariably showed increased myoglobin (mean, 8.3-fold normal), whereas CK was often normal (mean, 1.6-fold normal). Peak myoglobin values occurred earlier than peak CK values (9.9 h vs 21.6 h, p less than 0.0005), but there was a significant correlation of peak values (myoglobin = 0.384CK - 0.264, r = 0.794, p less than 0.0005). The mean exponential disappearance rate (Kd) of CK was 0.00106 min-1 and of myoglobin was 0.00265 min-1 (p less than 0.0005). The disappearance of myoglobin was well described by a mono-exponential expression except in two patients. The total duration of the increase in myoglobin was significantly less than that of CK (34.7 h vs 74.4 h, p less than 0.0005).
Optimized atomic absorption spectrophotometry of zinc in cerebrospinal fluid.
Authors: Palm R , Sjöström R , Hallmans G 
Published: January 2020

Abstract
This method for direct determination of Zn in cerebrospinal fluid (CSF) involves flame atomic absorption spectrophotometry with a pulse nebulizer technique. Standard solutions of Zn in 150 mmol/L NaCl were used. We could account for 88% of added standard with the method in individual samples from 10 patients and in pooled CSF. The method is acceptably precise, CVs in pooled CSF ranging from 4 to 12%. The mean CSF-Zn concentration for nine healthy men was 0.18 (SD 0.04) mumol/L and for nine healthy women 0.15 (SD 0.03) mumol/L, a statistically insignificant difference. These values are lower than those in previous reports, which may have been the result of contamination problems, nonatomic absorption, or nonstandardized sampling. In the healthy volunteers, the CSF-Zn concentration was positively correlated with serum-Zn, CSF-protein, and CSF-albumin concentrations, as well as with the CSF/serum ratio for albumin.
Lipid concentrations in serum and EDTA-treated plasma from fasting and nonfasting normal persons, with particular regard to high-density lipoprotein cholesterol.
Authors: Folsom A R , Kuba K , Leupker R V , Jacobs D R , Frantz I D 
Published: January 2020

Abstract
Serum/plasma sample pairs, collected both during (12-h) fasting and nonfasting from 44 healthy subjects, were analyzed for total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides. Values for total cholesterol and triglycerides averaged 2.1% and 5.2%, respectively, higher for serum than for plasma. Values for HDL cholesterol were not different. Triglyceride concentrations in nonfasting subjects were 40% higher than concentrations during fasting, but total cholesterol and HDL cholesterol were not significantly affected by fasting. These findings suggest that concentrations of HDL cholesterol may be directly compared in clinical and epidemiological settings without regard to whether serum or plasma was sampled or whether the subjects were fasting or nonfasting.
A peroxidase-coupled method for the colorimetric determination of serum triglycerides.
Authors: McGowan M W , Artiss J D , Strandbergh D R , Zak B 
Published: January 2020

Abstract
We describe an enzymatic method for rapid, precise measurement of serum triglycerides with use of sample:reagent ratios as large as 1:200. Hydrolysis of triglycerides is catalyzed by lipase to produce glycerol and free fatty acids. The glycerol generated is then phosphorylated by adenosine 5'-triphosphate in the presence of glycerol kinase. Oxidation of the resulting glycerol 3-phosphate to produce hydrogen peroxide is catalyzed by L-alpha-glycerophosphate oxidase. An intense red chromogen is produced by the peroxidase-catalyzed coupling of 4-aminoantipyrene and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate with hydrogen peroxide. This sensitive chromogen system not only permits use of unusually small sample volumes, it also facilitates a linear response to serum triglyceride concentrations up to at least 10 g/L while displaying good Ringbom (measure of accuracy) characteristics.
Identification of the serum binding proteins for iron, zinc, cadmium, nickel, and calcium.
Authors: Scott B J , Bradwell A R 
Published: January 2020

Abstract
The binding of five biologically important metals to serum proteins has been studied. After suitable radioactive isotopes were added to serum proteins separated and precipitated by two-dimensional immunoelectrophoresis, the sample plates were exposed to roentgenogram film. 59Fe bound to transferrin alone; 65Zn bound mostly to albumin, but also to another 12 proteins; 109Cd was mostly associated with alpha 2-macroglobulin, but was also present on albumin, immunoglobulins G and A, and prealbumin; 63Ni, added in high concentration, was associated with an alpha 2-mobility protein and albumin; and, finally, 45Ca was mostly bound to albumin, but seven other binding proteins were also identified, with transferrin predominant. The results are not quantitative, but the technique is simple and specific, and the information gained can direct further studies on isolated proteins.
Relationships among human amniotic fluid dipalmitoyl lecithin, postpartum respiratory compliance, and neonatal respiratory distress syndrome.
Authors: Lohninger A , Salzer H , Simbruner G , Husslein P , Martin G 
Published: January 2020

Abstract
The major molecular species of amniotic fluid phosphatidylcholine were determined as diacylglycerol trimethylsilyl ether derivatives by gas-liquid chromatography with use of glass capillary columns. We studied amniotic fluid specimens from 48 pregnancies. As expected, the major disaturated species of amniotic fluid phosphatidylcholine, dipalmitoylphosphatidylcholine, and palmitoylmyristoylphosphatidylcholine increased with gestational age, whereas phosphatidylcholine species with 34, 36, and 38 carbon atoms in the acyl radicals decreased. Although the amniotic fluid samples were obtained shortly before parturition (4.2 +/- 3.7 h, mean +/- SD), the correlation between dipalmitoylphosphatidylcholine concentration in amniotic fluid and gestational age was better than between dipalmitoylphosphatidylcholine concentration and the compliance of the respiratory system of the newborns. In addition, the percentage of amniotic fluid phosphatidylcholine species present as dipalmitoylphosphatidylcholine seemed to be a more reliable predictor of lung maturity than was the absolute dipalmitoylphosphatidylcholine concentration in amniotic fluid.
Does lactate dehydrogenase isoenzyme-5 contribute to the predictive power of total lactate dehydrogenase in myocardial infarction?
Authors: Chapelle J P , Albert A , Smeets J P , Maréchal J P , Heusghem C , Kulbertus H E 
Published: January 2020

Abstract
In 385 patients with acute myocardial infarction, lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes were determined electrophoretically 24, 48, and 72 h after admission. At those times, LD-1/LD-2 ratios exceeding 1 were recorded in 78.9, 88.8, and 92.2% of the cases, respectively. LD-1 ranged from 181 to 2674 U/L, or 21.9 to 66.1% of the total activity. On the first day of hospitalization, 27.3% of the patients demonstrated abnormal LD-5 (greater than 6% of total LD); this finding dropped to 20.5% and 17.4% in the two following days. Early increases in LD-5 were most frequently observed in patients associating inferior infarcts with posterior or lateral extension and having a previous history of myocardial infarction. On day 1, LD-5 was significantly increased in early deceased patients as compared to long-term survivors (9.7% vs 4.9% of total LD, p less than 0.01). LD-5 definitely contributes to the prognostic efficiency of total LD in acute myocardial infarction, but does not replace it as a risk predictor. This study confirms the superiority of total LD over the isoenzyme measurements to achieve short-term prognostication.
Utility of isoelectric focusing of cerebrospinal fluid and serum on agarose evaluated for neurological patients.
Authors: Link H , Kostulas V 
Published: January 2020

Abstract
Agarose isoelectric focusing was used to demonstrate oligoclonal bands in cerebrospinal fluid (CSF) and serum from 998 consecutive neurological patients. Compared with agarose electrophoresis, agarose isoelectric focusing was slightly more sensitive, showing more (and more easily discernible) oligoclonal bands. Agarose isoelectric focusing, which has good reproducibility, revealed oligoclonal bands in CSF in 95% of 43 patients with multiple sclerosis, 44% of 39 with aseptic meningoencephalitis, and 14% of 906 with other neurological diseases. Interestingly, oligoclonal bands were found in CSF from 12% of 162 patients with acute cerebral infarction and 23% of 53 with polyneuropathy, and also in 29% of 17 with dementia, while only 4% of 206 patients with headache, vertigo, or psychoneurosis had this CSF abnormality. We recommend this procedure for the routine examination of paired CSF and serum specimens for the presence of oligoclonal bands.
Salicylate determined with a microcentrifugal analyzer, and compared with Du Pont aca, trinder, and liquid-chromatographic methods.
Authors: Eckfeldt J H , Nelson K M 
Published: January 2020

Abstract
We describe a new automated method for measuring serum salicylate in the Multistat III microcentrifugal analyzer. Ferric nitrate reagent and serum blanking are used. We compare this new method, the automated Du Pont aca method, and the manual Trinder method with a "high-performance" liquid-chromatographic method. The unblanked Trinder method had the poorest correlation (r = 0.980, Sy X x = 19.1) with the chromatographic method. The serum-blanked aca and Multistat III methods showed better correlation (r = 0.995, Sy X x = 9.5 mg/L, and r = 0.991, Sy X x = 13.0 mg/L, respectively) with the chromatographic method. However, we conclude that all three colorimetric methods give clinically useful results and that the increased time, expense, and expertise required for chromatographic salicylate analysis are difficult to justify in a routine clinical laboratory.
Interpretation of cerebrospinal fluid protein assays in various neurologic diseases.
Authors: Christenson R H , Behlmer P , Howard J F , Winfield J B , Silverman L M 
Published: January 2020

Abstract
Albumin and immunoglobulin G (IgG) were determined in cerebrospinal fluid (CSF) and serum, and the CSF/serum albumin Index (CSF X 10(3)/serum albumin concentration ratio) and IgG Index [(CSF/serum IgG)/(CSF/serum albumin)] were calculated. Data for these indices and oligoclonal banding are described in 23 cases of multiple sclerosis (MS), 19 of systemic lupus erythematosus (SLE), eight of sarcoidosis, 48 cases of miscellaneous disease, and 25 control patients with nonspecific complaints. Of the MS, SLE, and sarcoidosis patient groups, 8.5%, 26%, and 12.5% showed an abnormally high CSF/serum albumin Index; 87%, 16%, and 0% an increased IgG Index; and 87.5%, 42% and 0% showed positive oligoclonal banding. IgG Index and oligoclonal banding results for MS patients differed significantly from the sarcoidosis (p less than .001) and SLE (p less than .05) groups. When the CSF/serum albumin Index is considered also, the control and sarcoidosis patient results differ significantly from the MS group (p less than .001 and p less than .01). A strong correlation between the IgG Index and oligoclonal banding is implicated.
Stability of estrogen- and progesterone-receptor concentrations in human uterus tissue.
Authors: Zachariah N Y , Chakmakjian Z H 
Published: January 2020

Abstract
Homogeneous control specimens for estrogen receptor (ER) and progesterone receptor (PR) assays were prepared from freshly collected human uterus. After removal of the connective tissue, the specimen was washed with isotonic saline, cut into small pieces, quickly frozen in liquid nitrogen, and stored at -70 degrees C until analyzed. Cytosol prepared from this specimen was lyophilized and stored at -70 degrees C. A single step of reconstitution, with glycerol (100 mL/L) in water, is sufficient to prepare a control. Two specimens prepared this way were found to be reasonably stable for 20 months (first specimen, mean +/- SD: ER = 22.1 +/- 2.9 fmol/mg, PR = 136.5 +/- 26.9 fmol/mg; second specimen: ER = 107.2 +/- 11.7 fmol/mg, PR = 922 +/- 71.6 fmol/mg). Another specimen, prepared similarly but not frozen in liquid nitrogen soon after collection, was less stable; its ER and PR concentrations deteriorated faster.
New "on-line" sample-pretreatment procedure for routine liquid-chromatographic assay of low-concentration compounds in body fluids, illustrated by triamcinolone assay.
Authors: Schöneshöfer M , Kage A , Weber B 
Published: January 2020

Abstract
In this fully automated technique for sample cleanup before chromatographic or other quantitation steps, analytes in body fluids are enriched and semi-purified on a first column. After their selective elution, analytes are "transformed" by admixing appropriate solvents in such a way that they are focused on the top of a second column. By backflush, they then are transferred to an analytical liquid-chromatographic column (or simply eluted for quantification by other techniques). This technique is illustrated by the liquid-chromatographic assay of triamcinolone from a 1-mL urine sample, with ultraviolet detection. Because analytical recovery is almost complete and precision high, no internal standardization is necessary. Interference is eliminated as well as or better than with manual techniques. Chief advantages of this technique are online operation, processing of samples of larger volume, low cost with respect to extraction devices, and nearly universal applicability for exogenous or endogenous compounds of clinical relevance. It potentially may be widely applied.
"Unbound analog" radioimmunoassays for free thyroxin measure the albumin-bound hormone fraction.
Authors: Stockigt J R , Stevens V , White E L , Barlow J W 
Published: January 2020

Abstract
We have assessed the influence of albumin-bound thyroxin (T4) on apparent free T4 values obtained by two "unbound analog" free T4 methods (AmerlexR Free T4 and Clinical Assays one-step Free T4). We evaluated sera showing three different albumin anomalies: total hereditary analbuminemia, partially corrected analbuminemia, and familial dysalbuminemic hyperthyroxinemia, where abnormal albumin-binding of analog tracer is associated with high apparent free T4 values by these methods. In hereditary analbuminemia, free T4 was almost undetectable by both assays; in contrast, free T4 by equilibrium dialysis was normal. After addition of T4-free human serum albumin, the apparent free T4 concentration in total hereditary analbuminemia became normal by the analog methods. Immunoprecipitation of [125I]T4 and the unidentified labeled kit analogs by antiserum to human albumin was negligible in untreated total hereditary analbuminemia and approximately twice normal in familial dysalbuminemic hyperthyroxinemia. Therefore, alterations in tracer binding to albumin correlate with the apparent free T4 concentrations obtained by the analog methods. The interactions of the unidentified analog tracers and T4 with albumin are such that these techniques principally reflect the albumin-bound T4 moiety.
Nonaqueous reversed-phase liquid chromatography and fluorimetry compared for determination of retinol in serum.
Authors: Nelis H J , De Roose J , Vandenbavière H , De Leenheer A P 
Published: January 2020

Abstract
A new assay for retinol in human serum, based on nonaqueous reversed-phase liquid chromatography, is presented. Sample preparation includes addition of the internal standard, retinyl propionate, deproteinization of 100 microL of serum with acetonitrile, and extraction with hexane. The standard curve is linear up to 2 mg/L. The assay is characterized by excellent sensitivity (detection limit, 15 micrograms/L) and good within-run and between-run precision (CVs of 2.6 and 2.7%, respectively), and results compare favorably with those by fluorimetry. We assayed 135 samples from hospitalized patients by both methods. Although the two sets of values correlated well (r = 0.955) the fluorimetric method occasionally suffers from interferences. In practice, fluorimetry proves valuable as a routine method, while liquid chromatography meets the criteria of a potential reference method.
Use of laser-excited fluorescence to measure mixed-function oxidase activity.
Authors: Egan B Z , Lee N E , Burtis C A , Kao J Y , Holland J M 
Published: January 2020

Abstract
The microsomal mixed-function oxidase (MFO) system is involved in the metabolism of various chemical compounds. Polycyclic aromatic hydrocarbons are metabolized by the cytochrome P-448 enzyme system, which contains MFOs. Induction of this MFO activity may be useful as an indicator of the toxicity of the inducer material. We have successfully used a portable centrifugal analyzer equipped with an argonion laser light source to quantify cytochrome P-448 activity induced in mouse-liver microsomes by exposing the animal's skin to different doses of liquids derived from a coal-liquefaction process. The MFO activity was determined kinetically by measuring the rate at which the highly fluorescent compound, resorufin, produced by the oxidation of 7-ethoxyresorufin substrate, was formed. The 514.5-nm laser excitation beam was directed with a fiber-optic bundle from the laser to the cuvets of a specially designed rotor; emitted fluorescence was monitored at 90 degrees to the incident beam through a 560-nm cut-on secondary filter. Use of the laser excitation source allowed very low MFO activities to be measured: picomole quantities of resorufin could be determined. We anticipate that the increased sensitivity of the method described here will allow MFO activities to be determined in body fluids and skin.
Molecular markers of hemostatic disorders: implications in the diagnosis and therapeutic management of thrombotic and bleeding disorders.
Authors: Fareed J , Bick R L , Squillaci G , Walenga J M , Bermes E W 
Published: January 2020

Abstract
With current technological advances, it is now possible to measure in less than 50 microL of plasma picomolar amounts of circulating products of platelet activation, products of protease activation related to coagulation and fibrinolytic pathways, and prostaglandin metabolites formed during a physiologic or pathologic process. Most of these markers, which circulate in blood in nanogram or picogram amounts per milliliter during or after pathologic activation, provide pertinent information on the status of a patient in terms of specificity and early detection, and will be of crucial value in the diagnosis of hemostatic defects and the management of newer antithrombotic drugs that cannot be monitored by currently available assays. Currently, 125I- and 3H-based simple radioimmunoassays are available for platelet factor 4, beta-thromboglobulin, fibrinopeptide A, B beta 15-42 related peptides, thromboxane B2, and the prostaglandins 6-keto-PGF1 alpha and PGE2. Nonisotopic methods such as enzyme-linked immunosorbent assays and fluoroimmunoassays are being developed. Serotonin and ADP, products of platelet activation, are measurable by liquid-chromatographic, immunoenzymatic, and spectrophotofluorometric methods. Analytical methods for fibrin split products (fragments D and E) and serine protease inhibitor complexes such as thrombin-antithrombin-III, factor Xa-antithrombin-III, and kallikrein-C1-esterase are also being developed. We have evaluated all of these methods and found them to be very sensitive to those components of endogenous activation of the hemostatic system listed above.
Two commercial methods evaluated for eliminating the labile fraction from the assay for glycated hemoglobin (glycohemoglobin).
Authors: Nathan D M , Dunn B S , Francis T B 
Published: January 2020

Abstract
Two recently introduced commercially available methods, a minicolumn and an electrophoresis assay, both effectively remove labile glycated hemoglobin generated in vitro and give results for patients' samples similar to those by liquid chromatography with samples pre-incubated in saline.
Salivary estriol concentrations during normal pregnancies, and a comparison with plasma estriol.
Authors: Evans J J , Wilkinson A R , Aickin D R 
Published: January 2020

Abstract
Saliva would have advantages over plasma or urine for monitoring estriol during pregnancy. Specimen collection, after stimulation of flow by citric acid, is non-invasive and simple. We measured concentrations of unconjugated estriol in saliva and compared them with those in plasma in normal pregnancies, and found a good correlation (r = 0.79). In addition, trends of concentrations in saliva and plasma were statistically compared and found to be highly correlated. The variation among individuals in the saliva/plasma concentration ratio suggested that some inter-individual factor(s) may affect this relationship. The normal reference interval for unconjugated estriol concentration in saliva from 20 weeks of gestation to term was established.