bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of renal function by inulin clearance: comparison with creatinine clearance as determined by enzymatic methods.
Authors: Apple F S , Benson P , Abraham P A , Rosano T G , Halstenson C E
Published: January 2020

We compared creatinine clearances determined by enzymatic (Kodak Ektachem 700 single-slide, Boehringer Mannheim creatinine PAP) and nonenzymatic (Jaffé, HPLC) methods with glomerular filtration rate measured by inulin clearance in patients with varying degrees of renal function. The Kodak enzymatic assay gave values for creatinine 2 to 3 mg/L higher than the other methods. This resulted in significantly lower creatinine clearances than inulin clearances and creatinine clearances determined by the other methods. However, correlations between all methods for serum and urinary creatinine values and clearances were good. To avoid between assay (enzymatic vs nonenzymatic) discrepancies, manufacturers should agree to an acceptable standard of calibration under the usual conditions used with patients.
Effectiveness of sodium fluoride as a preservative of glucose in blood.
Authors: Chan A Y , Swaminathan R , Cockram C S
Published: January 2020

How effective is sodium fluoride as a preservative of blood glucose? We compared changes in glucose concentration in fluoride-treated blood specimens with those of heparin-treated specimens. The former declined rapidly during the first hour; thereafter the rate of decrease was slower, and after 4 h the glucose concentration in the blood samples remained stable for up to three days. In contrast, the glucose concentration in the heparin-containing samples declined continuously. During the first hour, however, the rates of decline in the two types of samples were similar. Evidently sodium fluoride takes effect slowly but effectively in preserving glucose in blood for at least three days. Its use, however, is unnecessary if the concentration of glucose is to be measured within the first hour after sampling.
Measurement of apolipoprotein B in plasma from hyperlipidemic subjects treated with cholestyramine or placebo: differential effects of storage at -70 degrees C.
Authors: Kafonek S , Bachorik P S , Kwiterovich P O
Published: January 2020

Using radial immunodiffusion, we measured apolipoprotein B (apoB) concentrations in fresh plasma from 216 hyperlipidemic male subjects and in aliquots of the same plasma stored at -70 degrees C for 22 months. At the time of sampling, 112 were being treated with cholestyramine, the rest with a placebo. ApoB concentrations in the stored samples were significantly and positively correlated with apoB concentrations in the fresh samples (r = 0.84, P less than 0.001), the mean (and SD) being 1680 (320) mg/L and 1570 (320) mg/L, respectively. This 6.5% decrease in the stored samples was statistically significant (P = 0.0005), but there was no significant correlation between the decrease in apoB values in the stored samples and plasma triglyceride concentrations measured in the fresh samples. The correlation between the two apoB analyses was greater in the cholestyramine-treated group (r = 0.90) than in subjects treated with the placebo (r = 0.75).
Four immunochemical methods for measuring C-reactive protein in plasma compared.
Authors: Grützmeier S , von Schenck H
Published: January 2020

Four immunochemical methods for measuring C-reactive protein (CRP) in plasma were compared: radial immunodiffusion (RID), electroimmunoassay (EIA), immunoturbidimetry (IT), and laser nephelometry (LN). Close agreement was found between RID and EIA (EIA = 0.96 RID + 7.7 mg/L, r = 0.977, n = 100), IT and EIA (EIA = 1.11 IT - 15.8 mg/L, r = 0.951, n = 100), IT and RID (RID = 1.10 IT - 11.5 mg/L r = 0.959, n = 94). In initial studies in 1983, LN showed good agreement with RID (LN = 0.98 RID + 11.9 mg/L, r = 0.973, n = 60). Since then, normal CRP values measured by LN have tended to increase and, at the time of the present study (1986), LN agreed poorly with other methods. The reason for this change is obscure. Having excluded the possibility of enzymatic degradation of CRP, we conclude that instrumentation problems are involved, and therefore we no longer use this method.
Liquid-chromatographic assay of urinary porphobilinogen.
Authors: Jamani A , Pudek M , Schreiber W E
Published: January 2020

This is a rapid (10 min per sample), highly sensitive procedure for quantifying urinary porphobilinogen (PBG). Interfering substances are removed by selectively adsorbing PBG onto an ion-exchange resin. After PBG is eluted with 0.5 mol/L formic acid, Ehrlich's reagent is added to produce the chromophore, which is then injected into a liquid chromatograph equipped with a diode-array detector. PBG is separated by a linear gradient (10% to 100%) of methanol in 10 mmol/L phosphate buffer, pH 3.0. Absorbance is monitored at 555 nm. Assay response varies linearly with PBG concentration over the range 0-110 mumol/L (0-25 mg/L). As little as 1.5 mumol/L (0.3 mg/L) can be detected. In prepared urine samples with known PBG concentrations, the within-run coefficient of variation (CV) ranged from 1.7% to 3.2%, the day-to-day CV from 3.5% to 6.1%. PBG concentrations in 24-h urine collected from 25 healthy subjects were all below the detection limit of the assay (less than 1.5 mumol/L). We used the new assay to measure PBG concentrations in the urine of two patients with latent porphyria. This method is more sensitive than spectrophotometric techniques currently used for measuring urinary PBG.
Micro-quantity tissue digestion for metal measurements by use of a microwave acid-digestion bomb.
Authors: Nicholson J R , Savory M G , Savory J , Wills M R
Published: January 2020

We describe a simple and convenient method for processing small amounts of tissue samples for trace-metal measurements by atomic absorption spectrometry, by use of a modified Parr microwave digestion bomb. Digestion proceeds rapidly (less than or equal to 90 s) in a sealed Teflon-lined vessel that eliminates contamination or loss from volatilization. Small quantities of tissue (5-100 mg dry weight) are digested in high-purity nitric acid, yielding concentrations of analyte that can be measured directly without further sample manipulation. We analyzed National Institute of Standards and Technology bovine liver Standard Reference Material to verify the accuracy of the technique. We assessed the applicability of the technique to analysis for aluminum in bone by comparison with a dry ashing procedure.
The new International Temperature Scale of 1990 (ITS-90).
Authors: Mangum B W
Published: January 2020

A new international temperature scale, the ITS-90, will replace the International Practical Temperature Scale of 1968 (amended edition of 1975), IPTS-68(75), on 1 January 1990. Temperatures on the ITS-90 will agree more closely with thermodynamic temperatures; therefore, the ITS-90 represents a substantial improvement over the IPTS-68(75). Fortunately for the clinical laboratory community, the change in the scale will be at most only 0.05 degrees C or less in the range from 0 to 60 degrees C, but corrections in primary calibrations should be made so that the calibrations are based on the ITS-90.
Sensitive, direct colorimetric assay for copper in serum.
Authors: Abe A , Yamashita S , Noma A
Published: January 2020

We have developed a sensitive procedure for determination of serum copper by use of the color reagent 4-(3,5-dibromo-2-pyridylazo)-N-ethyl-N-sulfopropylaniline. After mixing serum sample and reagent, and incubating at 37 degrees C for 5 min, we measure the absorbance of the resulting chelate complex at 580 nm (molar absorptivity, 80,000 L.mol-1.cm-1). Results of the method varied linearly with copper concentration to at least 5 mg/L; the lower limit of detection was 0.1 mg/L. Within-run CVs were 1.6% and 3.3% for copper concentrations of 1.03 and 0.72 mg/L, respectively (n = 10 each). Between-run CV was 2.8% at 1.22 mg/L (n = 14). Results of the proposed method (y) correlated well with those determined by standard atomic absorption spectrophotometric techniques (x): y = 0.99x - 0.02 mg/L; Syx = 0.08; r = 0.977; n = 56. Iron, zinc, cadmium, cobalt, and lead do not interfere.
Quantitative analysis for organic acids in biological samples: batch isolation followed by gas chromatographic-mass spectrometric analysis.
Authors: Hoffmann G , Aramaki S , Blum-Hoffmann E , Nyhan W L , Sweetman L
Published: January 2020

This new method for qualitative and quantitative determination of organic acids, aldehydes, and ketones in biological samples is effective for use with urine, plasma, and amniotic fluid, and it requires no deproteinization. Isolation by batch-wise liquid partition chromatography on silicic acid follows formation of the O-(2,3,4,5,6-pentafluorobenzyl)oximes of oxoacids, aldehydes, and ketones. The total organic acid content of the sample provides a rapid screening test for metabolic abnormality. A wide-bore, bonded-phase capillary column was used for quantitative gas chromatographic-mass spectrometric analysis, followed by automated identification and quantification. Analytical recoveries were quantitative for a wide variety of metabolites. Gas-chromatographic retention indices, discriminating ions, and control ranges in amniotic fluid, plasma, and urine of adult subjects were determined for 61 biologically important compounds.
Hormonal evaluation of female infertility and reproductive disorders.
Authors: Scott M G , Ladenson J H , Green E D , Gast M J
Published: January 2020

Performance of the male and female reproductive systems reflects the orderly operation of the hypothalamic-pituitary-gonadal axis. Aberrant operation of this axis can result in many different reproductive disorders, including various forms of infertility. Proper evaluation of these disorders involves a multifaceted diagnostic approach, which includes a critical contribution from the clinical laboratory. This adjunctive testing, involving the measurements of peptide and sex-steroid hormone concentrations, allows the clinician to biochemically "dissect" the hypothalamic-pituitary-gonadal axis and ascertain the presence as well as location of the specific defect. In practice, the specific tests utilized during the evaluation of a patient depend upon the underlying disorder. Typically, in evaluating the reproductive disorders discussed in this review, a primary battery of tests is obtained that reflects the initial clinical presentation and physical examination. The results of these initial studies then dictate any secondary testing required to complete the evaluation. Such an approach, in use at our institution, is provided in Table 5. Although this discussion has concentrated on the laboratory assessment of the female reproductive system, it is important to remember the special case of infertility, where couples, in general, are evaluated together by the clinician. The cause of infertility can reside with the female, the male, or, in the cases of immunological "incompatibilities," a combination of the male and the female. As such, rigorous schemes for evaluating male reproductive disorders (1, 3, 89-94) and immunological incompatibilities (95-98) have been developed, and the information derived from such testing represents a critical contribution to establishing the etiology of a couple's infertility. Although the laboratory assessment of peptide and sex-steroid hormone concentrations clearly plays a pivotal role in the evaluation of reproductive disorders, these diagnostic tools probably will continue to change and improve in the years to come. Such changes will probably occur as the finer details of the operation of the hypothalamic-pituitary-gonadal axis become known. With this improved knowledge, we should have the capacity to design assays that will allow more clinically refined and biochemically precise means of diagnosing and treating specific reproductive disorders.
Significance of low serum urea nitrogen concentrations.
Authors: Lum G , Leal-Khouri S
Published: January 2020

The prevalence of low serum urea nitrogen concentrations (less than 50 mg/L) in our patient population was 1.2% (151 per 12,380 determinations), representing 95 individual cases. Of these, 81 of the patients' charts were located, reviewed, and classified into two groups, those with and those without hepatobiliary disease. Hepatobiliary disease was found in 36% of the 81 patients; 90% of these showed evidence of alcohol abuse, as did 19% of those without hepatobiliary disease. The remaining patients without hepatobiliary disease had various clinical conditions: psychiatric disorders (14.8%), overhydration (12.3%), endocrine disorders (7.4%), cardiovascular diseases (4.9%), prednisone administration (3.7%), and special diets (2.5%). Thus, in our patient population the most frequent cause of low serum urea nitrogen concentrations was alcohol abuse, found in about half of the cases.
Multicenter evaluation of TDx test for assessing fetal lung maturity
Authors: Russell J C , Cooper C M , Ketchum C H , Torday J S , Richardson D K , Holt J A , Kaplan L A , Swanson J R , Ivie W M
Published: January 2020

"TDx Fetal Lung Maturity," an automated assay that measures the relative concentrations of surfactant and albumin in amniotic fluid, was compared with the lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol determination at five clinical sites. A total of 695 amniotic fluid samples were analyzed, of which 312 were followed by delivery of the infant within three days of sample collection. Of these 312, 24 developed respiratory distress syndrome and seven developed transient tachypnea. With the cutoff for maturity set at a surfactant/albumin value of 50 mg/g, the assay showed a sensitivity of 0.96 and a specificity of 0.88 for all samples, compared with a sensitivity of 0.96 and a specificity of 0.83 for the L/S ratio. The combination of rapid assay (30 min), accurate results, and uniformity among testing centers makes the TDx assay a very promising method.
Dissociation of immunocomplexes by ionic shock for the development of immunosensors: application to measurement of alpha 1-fetoprotein.
Authors: Boitieux J L , Biron M P , Desmet G , Thomas D
Published: January 2020

We report here our experimental results on the reaction rate of immunological complexes and on potential repeated use of membranes as a result of dissociation of the complexes between alpha 1-fetoprotein and catalase-labeled antibodies by different buffers with various ionic strengths. The measurement consists of an immunological process and an enzymatic reaction. The protein membrane activated by glutaraldehyde for the immobilization of antibodies is fixed over an oxygen electrode. After incubation with antibody/alpha 1-fetoprotein and antibody/alpha 1-fetoprotein antibodies coupled to catalase, the reaction medium is introduced into a continuous-flow cell. Oxygen production by the catalase is measured on-line, with the electrode in contact with hydrogen peroxide. This response is correlated to the alpha 1-fetoprotein concentration of the sample. We show a typical calibration curve between 0.5 and 120 micrograms/L. Replicate (n = 20) equilibrium measurement with the same membrane gave a CV of 2.2%. The reversible immunochemical sensor has been tested for 30 measurements without significant loss of activity.
Evaluation of a kinetic method for prostatic acid phosphatase with use of self-indicating substrate, 2,6-dichloro-4-nitrophenyl phosphate.
Authors: Valcour A A , Bowers G N , McComb R B
Published: January 2020

The purity, spectral characteristics, and rate of nonenzymatic hydrolysis of 2,6-dichloro-4-nitrophenyl phosphate (DCNPP) were determined. Rates of DCNPP hydrolysis by prostatic acid phosphatase (PAP) and erythrocytic acid phosphatase (EAP) (both EC 3.1.3.2) were measured in the absence and in the presence of various alcohols. 1.5-Pentanediol was the most effective transphosphorylation agent for specifically enhancing the activity of PAP. 1,4-Butanediol also enhanced PAP activity but markedly inhibited EAP activity. Bovine and human serum albumin preparations also accelerated the hydrolysis of DCNPP. DCNPP can be used for the continuous or multipoint-rate assay of PAP.
Advances in cyclosporine pharmacology, measurement, and therapeutic monitoring.
Authors: Shaw L M
Published: January 2020

This review will focus on our current state of understanding of the cellular and molecular mechanisms by which CsA exerts immunosuppression and will present new information on: pharmacokinetic variability of CsA, selection of specimen and method for measuring CsA concentration, identity of CsA metabolites and their immunosuppressive and toxic activity, and the relationship between steady-state pre-dose concentrations of CsA in blood and response to treatment in transplant patients.
Special considerations for geriatric therapeutic drug monitoring.
Authors: Annesley T M
Published: January 2020

Numerous physiological changes during the normal aging process can potentially affect how drugs are handled by the body. Gastrointestinal changes include increased gastric pH, decreased intestinal motility, and decreased blood perfusion. Age-related changes in body composition and protein concentrations in plasma contribute to alterations in the distribution of drugs. Hepatic metabolism of drugs may be affected, and renal excretion via glomerular filtration or tubular secretion is diminished. The importance of each of these physiological changes in the elderly, as well as the contribution of multi-drug therapy and other external factors, is discussed.
Benzodiazepines identified by capillary gas chromatography-mass spectrometry, with specific ion screening used to detect benzophenone derivatives.
Authors: Jones C E , Wians F H , Martinez L A , Merritt G J
Published: January 2020

We developed algorithms for confirmation and identification of benzodiazepines and their metabolites, initially detected in urine samples by enzyme-multiplied immunoassay (EMIT). These algorithms are based on the pattern of benzophenone derivatives of benzodiazepines obtained by gas chromatography-mass spectrometry (GC-MS) with use of a modified specific ion selection mode. Benzophenone derivatives were produced by acid hydrolysis of urine samples containing benzodiazepines and (or) their metabolites. We present mass spectra of the newer benzodiazepines--alprazolam, midazolam, and triazolam--and we determined the detection limit (0.2 mg/L) for these drugs as measured with the EMIT d.a.u. benzodiazepine assay and the ETS instrument (both from Syva Co.). We conclude that these algorithms are useful mostly in forensic toxicology in which unequivocal identification of benzodiazepines is the desired goal.
Alkaline phosphatase isoenzymes in plasma in hyperthyroidism.
Authors: Tibi L , Patrick A W , Leslie P , Toft A D , Smith A F
Published: January 2020

Alkaline phosphatase (ALP; EC 3.1.3.1) isoenzymes were measured in the plasma of 63 untreated hyperthyroid patients (the hyperthyroid group), 58 treated hyperthyroid patients, and 100 blood donors. Total, liver, and bone ALP activities were significantly higher in the hyperthyroid group than in the treated hyperthyroid group or the blood donors. Bone ALP was more frequently and more markedly abnormal than liver ALP. Intestinal ALP did not differ significantly between the groups. The hyperthyroid patient group had significantly higher plasma calcium concentrations and lower serum parathyrin concentrations than those of the treated hyperthyroid group.
Electrothermal atomic absorption spectrometric determination of aluminum: elimination of serum matrix effects.
Authors: Gitelman H J , Alderman F R
Published: January 2020

An improved electrothermal atomic absorption spectrometric method for determination of aluminum in serum is described. An ammonium hydroxide/sulfuric acid diluent is used to control matrix effects from serum constituents. Because serum produces no apparent matrix effects with this diluent, one can accurately calibrate the procedure with aqueous standards.
Multipoint kinetic method for simultaneously measuring the combined concentrations of acetoacetate-beta-hydroxybutyrate and lactate-pyruvate.
Authors: Nuwayhid N F , Johnson G F , Feld R D
Published: January 2020

This is a multipoint kinetic method for simultaneously determining acetoacetate (AcAc) plus beta-hydroxybutyrate and lactate plus pyruvate in a single cuvette of the Multistat III centrifugal analyzer. In the first step, AcAc and pyruvate are completely reduced, using 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) and lactate dehydrogenase (EC 1.1.1.27) in the presence of excess NADH at pH 7.5, to beta-hydroxybutyrate and lactate, respectively. After dilution, the endogenous beta-hydroxybutyrate and lactate and that resulting from reduction are simultaneously oxidized by their respective dehydrogenases in the presence of excess NAD+ at pH 9.0. Adjustment of the relative enzyme concentrations allows simultaneous estimation of AcAc plus beta-hydroxybutyrate and lactate plus pyruvate by analyzing multipoint absorbance data, collected during the oxidation reaction, with use of a two-component linear-regression model. Total run-to-run CVs were 6.4% and 6.1% at 5 mmol/L beta-hydroxybutyrate and 5 mmol/L lactate, respectively. The method was designed to be useful for identifying the cause of an increased anion gap in serum.
Use of molecular probes to detect human cytomegalovirus and human immunodeficiency virus.
Authors: Spector S A , Hsia K , Denaro F , Spector D H
Published: January 2020

Human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV) cause severe disease. The identification of these viruses in clinical specimens and understanding the progression of infection and diseases relating to HCMV and HIV are essential to develop effective means for treatment and prevention. Here we describe the application of molecular probes to the diagnosis and pathogenesis of HCMV and HIV. In situ hybridization and the amplification procedure of polymerase chain reaction are used to detect both viruses; these techniques have provided important information regarding the pathogenesis of HCMV and HIV. A new technique, target cycling, may also prove useful for the detection of viruses by enriching for target sequences. The continued application of molecular probes to pathogenetic studies of HCMV and HIV promises to further our knowledge of these viruses, and of their interaction.
Simultaneous liquid-chromatographic determination of some bronchodilators, anticonvulsants, chloramphenicol, and hypnotic agents, with Chromosorb P columns used for sample preparation.
Authors: Svinarov D A , Dotchev D C
Published: January 2020

We describe a simple liquid-chromatographic system for simultaneously measuring bronchodilators, anticonvulsants, hypnotics, and chloramphenicol. Use in therapeutic drug monitoring includes determination of theophylline, caffeine, chloramphenicol, ethosuximide, primidone, phenobarbital, phenacemide, phenytoin, mephenytoin, nirvanol, and carbamazepine and its bioactive metabolites within 13 min. In the "toxicology mode" theophylline, caffeine, barbital, butabarbital, pentobarbital, amobarbital, secobarbital, primidone, phenobarbital, methylprylon, glutethimide, methaqualone, phenytoin, mephenytoin, nirvanol, and carbamazepine and its bioactive metabolites are resolved within 17 min. A reversed-phase C8 column (5-microns particles) is used, with acetonitrile/water (20/80 by vol) as mobile phase. The drugs are extracted from 50 microL of serum with use of a Chromosorb P microcolumn and chloroform/isopropanol (6/1 by vol). The drugs are quantified by absorbance at 208 nm, with tolylphenobarbital as internal standard. Lower limits of detection varied from 0.05 to 0.1 mg/L, analytical recovery from 94% to 106%; CVs were less than 5.6% within run, less than 6.9% between runs.
Quantification of urinary porphyrins by liquid chromatography after oxidation of porphyrinogens.
Authors: Abe K , Konaka R
Published: January 2020

A quantitative "high-performance" liquid-chromatographic method is described for determining porphyrins in human urine. Porphyrinogens in urine are first converted to the corresponding porphyrins by oxidation with iodine. Uroporphyrin, hepatacarboxylic acid porphyrin, hexacarboxylic acid porphyrin, pentacarboxylic acid porphyrin, and coproporphyrin I and III isomers are then separated on a reversed-phase column and measured by fluorometry. Analysis for the six porphyrins is complete within 24 min, including reconditioning for the next sample. The detection limit (twice the signal/noise ratio) for each porphyrin was 1 nmol/L for urine (25 fmol per 50-microL injection). Mean analytical recovery of each porphyrin ranged from 85% to 91%, within-day CVs from 1.4% to 7.3%. Normal reference intervals for porphyrins were established by assaying urine samples from 75 healthy subjects. Significant sex-related differences in coproporphyrin I and III isomers were evident when the values were expressed as nanomoles per gram of creatinine. Coproporphyrin isomer ratio was estimated for utility in the diagnosis of porphyrinurias.
Practical automation and interpretation of quantitative assays of antibodies to therapeutic proteins, illustrated with human growth hormone.
Authors: Sportsman J R , Smith W C , Winely C L
Published: January 2020

To quantify concentrations of anti-growth hormone antibody in less than 600 serum samples by radioimmunoassay, we devised a system ("BOLAC") to process data and to execute the curve-fitting program LIGAND-PC automatically with an IBM PC-compatible computer. We fit data from each sample to four binding and one or two-antibody binding sites. Total antibody concentration is then calculated from the model that is statistically "best". This process occasionally selects a two-binding-site model that severely overestimates the antibody concentration. Errors of this kind are discarded by constraining the product of the second-site antibody's affinity and its concentration to exceed a minimum value (0.05). We evaluated the performance of the BOLAC system by assaying controls and by using computer simulations to demonstrate the high confidence levels attainable in estimation of antibody concentrations. Between-assay variability (CV) was less than 25%, and analytical recovery exceeded 90%. These figures are acceptable for an assay based on curve-fitting of competitive radioimmunoassay data, allowing clinically relevant assessments of antibody responses in patient's samples. The advantages of the BOLAC system include high throughput and the reporting of results in absolute units of affinities and concentrations.
Functional activity of protein S determined with use of protein C activated by venom activator.
Authors: Kobayashi I , Amemiya N , Endo T , Okuyama K , Tamura K , Kume S
Published: January 2020

A new screening procedure, an easy and specific assay for determining functional Protein S activity, has been developed, with use of Protein C activated by venom activator (Protac). Purified Protein C (100% amidolytic activity) was activated by venom activator (6 units/mL). To a mixture of 100 microL of Protein S-deficient plasma, 20 microL of sample plasma, 100 microL of cephalin (Actin), and 20 microL of activated Protein C we added 100 microL of 25 mmol/L CaCl2 solution and measured the clotting time with a KC 10 coagulometer. The functional Protein S activity correlated well with the concentrations of Protein S antigen measured by enzyme immunoassay and the Laurell rocket technique (r = 0.810 and 0.850, respectively) in normal subjects, patients with myocardial infarction undergoing warfarin therapy, and patients with liver cirrhosis.
Implications of probability analysis for interpreting results of leukocyte esterase and nitrite test strips.
Authors: Bolann B J , Sandberg S , Digranes A
Published: January 2020

We examined 288 urine samples, using test strips, sediment microscopy, and culture. The ability of the leukocyte esterase and nitrite test strips to detect or exclude urinary tract infection, as defined by a positive culture, was evaluated by probability analysis. We found that the diagnostic efficiency of the esterase-nitrite combination was similar to that of sediment microscopy. Moreover, once the strip test results had been obtained, little additional information was given by microscopy. The importance of estimating the prevalence, or pre-test probability, of infection before the test result is evaluated is emphasized. We conclude that, for detecting or excluding urinary-tract infection, microscopy can be replaced by the esterase and nitrite test strips. If the probability of infection predicted by the test strips is not high (or low) enough compared with medical decision limits, the samples should be cultured.
"Stat" measurements of L-lactate in whole blood and cerebrospinal fluid assessed.
Authors: Wandrup J , Tvede K , Grinsted J , Jordening H
Published: January 2020

A first-generation semi-automatic amperometric lactate analyzer (Yellow Springs Instrument Co.) was assessed for urgent ("stat"), rapid laboratory measurements in whole blood and cerebrospinal fluid. For whole blood, measured lactate concentration and hematocrit were linearly correlated. An improved equation is presented for estimating the concentration of lactate in plasma from measurements in whole blood. The 95% reference range for the concentration of lactate in paired samples of capillary and venous whole blood from 40 healthy laboratory adults was found to be 0.4-1.5 mmol/L and 0.3-1.5 mmol/L, respectively. The 95% ranges for lactate in whole blood from 24 uncomplicated vaginal deliveries at term were established for cord venous blood, 1.2-5.0 mmol/L; cord arterial blood, 1.6-5.5 mmol/L; and maternal venous blood, 1.7-6.6 mmol/L. The 95% paired ranges were established for 20 lumbar-anaesthetized urological patients without neurological disorders after induction of anaesthesia for venous whole blood and cerebrospinal fluid (venous blood, 0.5-1.3 mmol/L; cerebrospinal fluid, 1.1-2.4 mmol/L).
Beta-hCG vs intact hCG assays in the detection of trophoblastic disease.
Authors: Rinker A D , Tietz N W
Published: January 2020

We describe a case of choriocarcinoma in which increased concentrations of beta-choriogonadotropin subunits in serum indicated recurrence of metastasis long before the tumor could be confirmed by visualization techniques, while intact choriogonadotropin remained normal (less than 5 int. units/L). Therefore, detection or monitoring of choriocarcinoma requires the assay of free beta-hCG subunit or an assay that measures both the free beta-subunit and intact choriogonadotropin.
Multilayer fluorescent immunoassay technique.
Authors: Grenner G , Inbar S , Meneghini F A , Long E W , Yamartino E J , Bowen M S , Blackwood J J , Padilla A J , Maretsky D , Staedter M
Published: January 2020

We describe a new multilayer immunoassay element for the determination of haptens in undiluted serum and plasma. Polysaccharide layers are coated onto a plastic base. The signal layer contains an immobilized antibody and a fluorescent-labeled hapten. A second layer, containing a pigment, acts as an optical screen. Sample spreading is achieved by a molded grid in contact with the upper layer of the immunoassay element. After sample is added to the element, endogenous analyte competes with the labeled hapten for the binding sites of the immobilized antibody; equilibrium is reached in 4-12 min. Because of the relative liquid-holding capacities of the layers and the grid, only a small amount of the free components remains in the signal layer. The signal is measured by front-surface fluorimetry. This technology has been applied to theophylline and thyroxin assays. Within- and between-run CVs range from 3% to 6%. Comparisons with fluorescent polarization immunoassays (Abbott TDx) showed excellent correlation (theophylline: r = 0.98, slope = 1.07, intercept = 0.3; thyroxin: r = 0.97, slope = 0.91, intercept = 0.8). The new method requires only one pipetting step (sample delivery) and is potentially applicable to a wide range of analytes.
Isolation of the "cystic fibrosis protein" from serum.
Authors: Barthe C , Carrere J , Figarella C , Guy-Crotte O
Published: January 2020

"Cystic fibrosis protein" (CFP), a minor serum protein marker of the cystic fibrosis allele, was isolated from serum from patients with cystic fibrosis by use of the "FPLC" high-resolution chromatography system and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. CFP currently is characterized by its isoelectric point (8.4) on isoelectric focusing. However, after the first purification steps, we identified the protein, which was present in a very low concentration, by the immunosorbent assay of Hayward et al. (J Immunol Methods 1986;91:117-22), by virtue of its immunological relationship with the "CF antigen," a protein characterized in granulocytes by these same authors [Nature (London) 1985;315:513-5]. CFP, a protein of low molecular mass, about 14 kDa, appears to be strongly associated with IgG in serum. Using the same procedure with control serum permits us to assume that CFP normally is present in serum in trace amounts.
Lactate dehydrogenase and its isoenzymes in serum from patients with multiple myeloma.
Authors: Copur S , Kus S , Kars A , Renda N , Tekuzman G , Firat D
Published: January 2020

Concentrations of total lactate dehydrogenase (LDH; EC 1.1.1.27) and LDH isoenzyme patterns were studied in serum of 19 patients with multiple myeloma and in 19 healthy controls. Patients were divided into three groups (pretreatment, nonresponders, and responders to treatment), based on their clinical status at the time of blood sampling for LDH. The LDH values were found to be significantly higher (P less than 0.05) in the pretreatment group and in the nonresponders than in the responders and the control group, the mean +/- SE values being 445 +/- 35 and 532 +/- 75 units/mL vs 349 +/- 75 and 190 +/- 7.1 units/mL, respectively. Compared with responders and healthy controls, newly diagnosed patients and nonresponders had slight diminutions in LDH-1 and LDH-2, but increased LDH-3. We conclude that determination of LDH and its isoenzymes in serum can be of value as prognostic factors in patients with multiple myeloma.
Test-strip method for measuring lactate in whole blood.
Authors: Shimojo N , Naka K , Nakajima C , Yoshikawa C , Okuda K , Okada K
Published: January 2020

We have developed a dry reagent strip system for measuring lactate in whole blood. The test strip contains lactate oxidase (no EC number assigned), horseradish peroxidase (EC 1.11.1.7), and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine. The system is designed to measure with a reflectometer the color that developed in the test strip, although the lactate concentration can be estimated without the reflectometer. The between-run coefficients of variation for controls at three concentrations were 2.9-5.3%. The lactate concentrations in blood samples from healthy subjects before and after exercise correlated well (r = 0.97) with the results measured by the comparison method with the use of lactate oxidase. This dry reagent strip system provides a convenient and rapid test for measuring blood lactate in clinical and sports medicine.
The origins of the (cooperative) species: Raiffeisen banking in the Netherlands, 1898–1909 1
Authors: Colvin Christopher L , Henderson Stuart , Turner John D
Published: January 2020

Cooperatively owned Raiffeisen banks first emerged in the Netherlands in the late 1890s and spread rapidly across the country. Using a new dataset, we investigate the determinants of their market entry and early performance. We find the cooperative organisational form, when allied to a change in the structure of Dutch agriculture and the socioreligious pillarisation of Dutch society, was an important factor explaining their entry into rural financial markets. While religious organisations provided a necessary impetus for the emergence of Raiffeisen banks, the economic advantages associated with cooperative enterprises ensured the subsequent survival and success of these banks.

“We will now discuss in a little more detail the Struggle for Existence.”

From Charles Darwin, The Origins of the Species (1859)
2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: executive summary
Authors: Cronin Edmond M , Bogun Frank M , Maury Philippe , Peichl Petr , Chen Minglong , Namboodiri Narayanan , Aguinaga Luis , Leite Luiz Roberto , Al-Khatib Sana M , Anter Elad , Berruezo Antonio , Callans David J , Chung Mina K , Cuculich Phillip , d’Avila Andre , Deal Barbara J , Della Bella Paolo , Deneke Thomas , Dickfeld Timm-Michael , Hadid Claudio , Haqqani Haris M , Kay G Neal , Latchamsetty Rakesh , Marchlinski Francis , Miller John M , Nogami Akihiko , Patel Akash R , Pathak Rajeev Kumar , Saenz Morales Luis C , Santangeli Pasquale , Sapp John L , Sarkozy Andrea , Soejima Kyoko , Stevenson William G , Tedrow Usha B , Tzou Wendy S , Varma Niraj , Zeppenfeld Katja
Published: January 2020

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.
Postponing vaccination in children with an infection: a qualitative study among general practitioners and pediatricians
Authors: Gonthier Damien , Basselin Pauline , Boivin Jean-Marc , Kivits Joelle , Pulcini Céline
Published: January 2020

Background

Vaccination postponement is an important contributing factor to low vaccination coverage. The causes of vaccine postponement are numerous, but the presence of viral infection, whether febrile or not, is the most frequent cause.

Objective

The objective was to explore the factors motivating the practice of vaccination postponement in a child with an infection by general practitioners (GPs) and paediatricians.

Methods

An exploratory qualitative study using semi-directive individual interviews was carried out among GPs and paediatricians in a French region between November 2015 and January 2018. After the interviews were fully transcribed, an analysis of the data was performed using an inductive method derived from the grounded theory.

Results

Fourteen GPs and four paediatricians participated in the study. Vaccination postponement during infection in children is rooted in doctors’ practices; it is considered a low-risk habit that is shared with parents, and vaccine hesitancy reinforces this practice. In children presenting with an infection, the presence of uncertainty about vaccine safety and effectiveness seems to justify postponing vaccination. The organization of a consultation dedicated to vaccination catch-up was cited as the best tool to limit the effects of vaccination delay on vaccination coverage.

Discussion

In children presenting with an infection, vaccination postponement is widely used by GPs and paediatricians. Simplification of the vaccination catch-up process and clear and consistent recommendations on the indications and modalities for vaccination postponement would be useful.
Spatial Patterns in Baseflow Mean Response Time across a Watershed in the Loess Plateau: Linkage with Land-Use Types
Authors: Huang Xu-dong , Wang Dong , Han Pei-pei , Wang Wen-chuan , Li Qing-jie , Zhang Xiao-li , Ma Ming-wei , Li Bao-jian , Han Shi-jie
Published: January 2020

Understanding the relation between land-use types and baseflow mean response time (BMRT) is important to explore the response mechanism of baseflow processes in watersheds. BMRT was determined using an instantaneous unit hydrograph. The instantaneous unit hydrograph parameters were estimated by autocorrelation functions. The relative importance of land-use types in determining BMRT dynamics was assessed by hydrological model and partial least-squares regression. Our study suggests greater effects of urban area on BMRT than the effects of forest and agricultural land. This may be because the urban interception impervious area may impede baseflow generation over a short timescale. The effects of agricultural land are greater than those of forest in areas with steeper hillslopes, but lower than those of the forest in areas with more plains, reflecting the varied ability of forest and agricultural lands with different topography to hinder overland flow. Variations of BMRT are strongly linked to land use in the watershed. Overall, our study provides insight into the BMRT and dominant factors of land-use types in watersheds, planning of sustainable water resource use, and ecological protection in watersheds.
High Levels of Physical Activity in Later Life Are Associated With Enhanced Markers of Mitochondrial Metabolism
Authors: Joanisse Sophie , Ashcroft Stephen , Wilkinson Daniel J , Pollock Ross D , O’Brien Katie A , Phillips Bethan E , Smith Ken , Lazarus Norman R , Harridge Stephen D R , Atherton Philip J , Philp Andrew
Published: January 2020

The age-associated reduction in muscle mass is well characterized; however, less is known regarding the mechanisms responsible for the decline in oxidative capacity also observed with advancing age. The purpose of the current study was therefore to compare mitochondrial gene expression and protein content between young and old recreationally active, and older highly active individuals. Muscle biopsies were obtained from the vastus lateralis of young males (YG: 22 ± 3 years) and older (OG: 67 ± 2 years) males not previously engaged in formal exercise and older male master cyclists (OT: 65 ± 5 years) who had undertaken cycling exercise for 32 ± 17 years. Comparison of gene expression between YG, OG, and OT groups revealed greater expression of mitochondrial-related genes, namely, electron transport chain (ETC) complexes II, III, and IV (p < .05) in OT compared with YG and OG. Gene expression of mitofusion (MFN)-1/2, mitochondrial fusion genes, was greater in OT compared with OG (p < .05). Similarly, protein content of ETC complexes I, II, and IV was significantly greater in OT compared with both YG and OG (p < .001). Protein content of peroxisome proliferator-activated receptor gamma, coactivator 1 α (PGC-1α), was greater in OT compared with YG and OG (p < .001). Our results suggest that the aging process per se is not associated with a decline in gene expression and protein content of ETC complexes. Mitochondrial-related gene expression and protein content are substantially greater in OT, suggesting that exercise-mediated increases in mitochondrial content can be maintained into later life.
Vitamin D Status of Adults in the Community, in Outpatient Clinics, in Hospital, and in Nursing Homes in the West of Ireland
Authors: Griffin Tomás Patrick , Wall Deirdre , Blake Liam , Griffin Damian Gerard , Robinson Stephaine M , Bell Marcia , Mulkerrin Eamon C , O’Shea Paula M
Published: January 2020

Background

Approximately 1 billion people worldwide have Vitamin D deficiency. The aim of this study was to compare Vitamin D status and serum 25-hydroxyvitamin D (25(OH)D) concentrations among adults sampled in the community, in outpatient clinics, as hospital inpatients and in nursing homes in the West of Ireland. The secondary aim was to determine the associations between length of hospital stay (inpatients) at the time of serum 25(OH)D sampling and Vitamin D status.

Methods

A cross-sectional study was carried out. Patients who had serum 25(OH)D analysis carried out in Galway University Hospitals (January 2011–December 2015) were identified following interrogation of the electronic laboratory data system. Baseline demographics, location, and date of sample collection were recorded. Vitamin D deficiency was defined as a serum 25(OH)D concentration <25 nmol/L.

Results

In total, 24,302 patient samples were eligible for inclusion: community 15,319; outpatient clinics 6,371; inpatients 2,339; and nursing home residents 273. Vitamin D deficiency was more common in nursing home residents than inpatients, or those sampled in outpatient clinics or in the community (42% vs 37% vs 17% vs 13%; p < .001). Inpatients sampled further into their hospital stay (≥3 days) had greater Vitamin D deficiency than inpatients sampled on 0–2 days (p = .007). Season (p < .001), sex (p < .001), and age (p < .001) were associated with 25(OH)D concentrations. Vitamin D deficiency was more common in Winter/Spring, in males, and in those aged ≥80 years.

Conclusions

Nursing home residents and inpatients are at the highest risk for Vitamin D deficiency. Season, sex, age, and day of hospital stay on which serum 25(OH)D concentrations were sampled were associated with Vitamin D status.
Informal Caregiving, Chronic Physical Conditions, and Physical Multimorbidity in 48 Low- and Middle-Income Countries
Authors: Jacob Louis , Oh Hans , Shin Jae Il , Haro Josep Maria , Vancampfort Davy , Stubbs Brendon , Jackson Sarah E , Smith Lee , Koyanagi Ai
Published: January 2020

Background

The health of the caregivers is crucial to sustain informal care provision, while multimorbidity is an important health risk concept. However, studies on the association between informal caregiving and physical multimorbidity are currently lacking. Therefore, we investigated this association in adults from 48 low- and middle-income countries (LMICs).

Method

Cross-sectional data from 242,952 adults (mean age 38.4 years) participating in the World Health Survey 2002–2004 were analyzed. Informal caregivers were considered those who provided help in the past year to a relative or friend (adult or child) who has a long-term physical or mental illness or disability, or is getting old and weak. Nine physical conditions were assessed. Multivariable logistic regression analyses were conducted to assess associations between informal caregiving and physical multimorbidity, while the between-country heterogeneity in this relationship was studied with country-wise analyses.

Results

The overall prevalence of informal caregiving and physical multimorbidity (ie, two or more physical conditions) was 19.2% and 13.2%, respectively. Overall, caregivers had 1.40 (95% confidence interval = 1.29–1.52) times higher odds for physical multimorbidity. This association was particularly pronounced in younger caregivers (eg, 18–44 years: odds ratio = 1.54; 95% confidence interval = 1.37–1.72), whereas this association was not statistically significant among those aged ≥65 and older (odds ratio = 1.19; 95% confidence interval = 0.98–1.44). Country-wise analyses corroborated these findings, and there was a negligible level of between-country heterogeneity (I2 = 24.0%).

Conclusions

In LMICs, informal caregivers (especially young caregivers) were more likely to have physical multimorbidity. This should be taken into account in policies that address the health and well-being of informal caregivers.
Little Guidance for the Application of Copyright Law to Designs in Cofemel
Authors: Endrich-Laimböck Tobias
Published: January 2020

Cofemel does not provide sector-specific guidance for the application of the originality criterion to works of applied art or industrial designs.