bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyrophosphate in Synovial Fluid and Urine and its Relationship to Urinary Risk Factors for Stone Disease
Authors: Roberts N B , Dutton J , Helliwell T , Rothwell P J N , Kavanagh J P 
Published: February 2014

Inorganic pyrophosphate (PPi) measurement in urine and synovial fluid has been established using the PPi-dependent phosphorylation of fructose-6-phosphate and subsequent reduction of dihydroxyacetone phosphate by NADH. The assay is linear up to 200 μmol/L, easy to perform and gives results comparable to more complex methods. Daily urinary output of PPi was independently related to both age ( P = 0·0014) and sex ( P = 0·0002). Men had higher values than women and older individuals excreted greater amounts. Male stone formers, younger than 45 years, had lower values than age matched male controls ( P = 0·012). Younger female stone formers also tended to have lower values. In stone formers' urine significant and independent correlations were found of PPi excretion with urine volume ( P = 0·004) and with phosphate excretion ( P = 0·008). Oxalate excretion and that of other urine constituents and the degree of supersaturation with common stone-forming salts were not correlated with PPi. PPi excretion was markedly elevated in the urine of two patients with hypophosphatasia. The PPi concentration in synovial fluid from painful, swollen knee joints was elevated, but unrelated to the presence or absence of PPi or urate crystals.
Enzyme Activities of the Mitochondrial Energy Generating System in Skeletal Muscle Tissue of Preterm and Fullterm Neonates
Authors: Sperl W , Sengers RCA , Trijbels J M F , Ruitenbeek W , Doesburg W H , Smeitink JAM , Kollée L A A , Boon J M 
Published: February 2014

Quadriceps muscle specimens from autopsy of 28 neonates (gestational age 25–42 weeks) were investigated to determine pyruvate and malate oxidation rates and several enzymes of the mitochondrial oxidative process. In general, the levels of all mitochondrial parameters measured, including carnitine levels, were lower in the neonates who died within the first week of life than those in the control group (age > 5 years). Pyruvate and malate oxidation rates ( P < 0·05), activities of pyruvate dehydrogenase complex ( P < 0·10) and succinate: Cytochrome c oxidoreductase ( P < 0·05) increased significantly with gestational age. Pyruvate oxidation rates ( P < 0·05) as well as activities of citrate synthase ( P < 0·05) and NADH:Q1 oxidoreductase ( P < 0·05) were significantly lower in the group of very preterm infants at an age of 1–7 days compared with very preterm infants at an age between 3–8 weeks. We conclude from our study that special reference values are necessary for a correct biochemical diagnosis of mitochondrial encephalomyopathies in the neonatal period. Differences between preterm and fullterm children of the same age (1 week) indicate a maturational process in human muscle tissue during gestation. Comparison of two different age groups within the very preterm neonates point to a postnatal maturation of the mitochondrial energy metabolism, at least in preterm neonates.
Plasma and 24 H-Urinary Catecholamine Concentrations in Normal and Patient Populations
Authors: Ross G A , Newbould E C , Thomas J , Bouloux P M G , Besser G M , Perrett D , Grossman A 
Published: February 2014

Using a single HPLC-ECD methodology, plasma catecholamine data were compiled from 545 patients and 144 healthy subjects, and 24 h urinary free catecholamine data from 106 patients. From these data, normal reference ranges were derived for the clinical investigation of suspected phaeochromocytomas, specifically to address the question as to when a result is normal and when further investigation may be required. We have shown that noradrenaline and adrenaline concentrations in plasma and urine are not normally distributed, and basal plasma noradrenaline is significantly lower in normal volunteers than in hospital patients. We have also demonstrated that a reference range which does not take account of these factors will give a significant number of false-positive results. Age and sex did not appear to be significant variables for either plasma or urinary catecholamines. In the investigation of phaeochromocytoma, 95% confidence limits may be used as a warning to repeat sampling and 99% confidence limits as rendering the diagnosis extremely probable. In patients with phaeochromocytomas, urinary catecholamines had a 99·5% specificity and 100% sensitivity in the diagnosis, and thus provide for a rapid and efficient diagnostic screen.
Clinical Relevance of Serum Amyloid a Protein Monitoring in Urinary Tract Infections
Authors: Časl Martin-Tino , Sabljar-Matovinović Mirjana , Kovačević Sandra , Počanić Darko , Preden-Kereković Vladimira , Jagarinec Nada 
Published: February 2014

We have evaluated the clinical relevance of monitoring acute phase proteins in severe urinary tract infection. Body temperature, white blood cell count, erythrocyte sedimentation rate, serum amyloid A protein (SAA), C-reactive protein (CRP), α-1-antichymotrypsin (ACT) and α-1-acid glycoprotein (AGP) were determined daily in sera from 18 treated patients. Two patterns of response could be identified: responders and non-responders whose therapy had to be changed. Mean values for each acute phase protein were calculated daily in both responders and non-responders. Statistical evaluation of the significance between the means for each protein was also performed on a daily basis and showed P < 0·01 for SAA and CRP on day 3, for ACT on day 5, and for AGP on day 6. SAA and CRP appear to be the most reliable markers for antimicrobial therapy monitoring in patients with urinary tract infections.
Between-Country Comparability of Clinical Chemistry Results: An International Quality Assessment Survey of 17 Analytes in Six European Countries through Existing National Schemes
Authors: Jansen R T P , Bullock D G , Vassault A , Baadenhuijsen H , De Leenheer A , Dumont G , de Verdier C-H , Zender R 
Published: February 2014

Two lyophilized control sera were distributed through seven national external quality assessment schemes in six European countries—Belgium, Switzerland, France, The Netherlands, Sweden and the United Kingdom—participated in the study. The results for 17 routine analytes were obtained from almost 5000 laboratories for the two sera. The organizers of the schemes were asked to process the results according to a common outlier removal procedure, and submit method-related data if available. The two sera were also distributed through the external/internal scheme of The Netherlands, and the within-laboratory standard deviations calculated in this scheme have been used in a scaling procedure for the external mean values and between-laboratory standard deviations of the participating countries. The results show remarkable agreement in the national mean values for practically all analytes, but considerable differences in the between-laboratory variation. Data from comparable method groups was obtained for 12 analytes from Belgium, France, The Netherlands and the UK. Though revealing some specific differences between methods and countries, the method-related data are generally in agreement with the all-method data. In this study reference method values were only available for cholesterol. The high degree of agreement found suggests, however, that mutual recognition of all-method mean values in national schemes could be acceptable, especially for analytes for which reliable reference methods are not available. The major element of variation is between-laboratory rather than between-country.
Dual Analyte Immunoassay in Neural Tube Defect and Down's Syndrome Screening: Results of a Multicentre Clinical Trial
Authors: Spencer K , Macri J N , Anderson R W , Aitken D A , Berry E , Crossley J A , Wood P J , Coombes E J , Stroud M , Worthington D J , Doran J , Barbour H , Wilmot R 
Published: February 2014

We report a multicentre clinical field trial of a novel dual analyte enzyme immunoassay method for the simultaneous measurement of alpha-fetoprotein (AFP) and free β-human choriogonadotropin (hCG) in the same microtitre well. The assay was shown to have good technical performance in the hands of all trial centres, with between assay coefficients of variation better than 10% for both analytes across the whole of the assay ranges. The method compared well with single analyte measuring procedures and produced acceptable performance as judged by external quality assurance criteria. Recovery of added analyte and analyte dilution curves also showed acceptable performance. In clinical evaluation of a large set of neural tube defect cases, good clinical discrimination from unaffected cases was observed using APP. With over 150 Down's syndrome cases, the combination of AFP and free (3 hCG confirmed the high detection rates achievable using this marker combination, with detection rates in excess of 70% in early gestation. We conclude that the combination of clinically superior markers coupled with technologically innovative assay design will lead to more efficient Down's screening programmes.
Clinical Associations of an Increased Transthyretin Band in Routine Serum and Urine Protein Electrophoresis
Authors: Tormey W P , O'Brien P A 
Published: February 2014

The 9697 electrophoretograms performed over an 8 year period were reviewed to identify the frequency and clinical associations of the finding of a prominent transthyretin band in serum or urine, the concentration of which was equal to or greater than a 64 mg/dL protein calibrator. All samples were electrophoresed at a constant 90 V using agarose gels with a barbital buffer pH 8·6 and Ponceau S staining. Reference calibrators were used as standards to identify increased transthyretin bands and the patients' clinical records were subsequently reviewed. High values were found in 46 patients' sera and a further nine patients' urines representing 0·57% of the total workload. Renal impairment was present in 58% of cases including those with chronic renal failure, the nephrotic syndrome and paraproteinaemia. The high levels were not persistent in three myeloma cases where there was a recovery in renal function following chemotherapy. In some nephrotics, a high urine transthyretin may be secondary to a general hepatic albumin and transport protein synthesis response to severe proteinuria. Why the serum transthyretin was elevated in many other cases remains unclear.
The Analysis of Metabolites in Human Sweat: Analytical Methods and Potential Application to Investigation of Pressure Ischaemia of Soft Tissues
Authors: Taylor Richard P , Polliack Adrian A , Bader Dan L 
Published: February 2014

A straightforward technique was developed for sweat collection applicable to tissues subjected to external load without introducing distortion of underlying tissues, and for analysis of six metabolites in the collected sweat. Chloride was measured colorimetrically and lactate, urea and urate by enzymatic methods on a centrifugal analyser. Sodium and potassium were measured by flame photometry. The methods showed good precision, recovery and linearity. To assess the technique sweat was collected: (i) from the sacrum, ischium, forearm and calf in healthy individuals at 32°C for 1 h; (ii) from the sacrum of healthy subjects at ambient temperature for 9 h; (iii) at ambient temperature from the sacrum of a patient with a history of pressure sores. Sweat rates were greater at the sacrum and ischium than the calf or forearm. There were differences in the concentrations of lactate and urea between sites but these were smaller when expressed as amount secreted. Sweat rates were significantly lower in groups (ii) and (iii), but sweat could be collected reliably. This technique has potential clinical application to the investigation of susceptibility to pressure sores.
Studies on Red Cell Glucose-6-Phosphate Dehydrogenase: Evaluation of Reference Values
Authors: Yüregir Günes T , Aksoy Kiymet , Arpaci Abdullah , Ünlükurt Isa , Tuli Abdullah 
Published: February 2014

The analytical, intra-individual, inter-individual variation and reference values were determined for red cell glucose-6-phosphate dehydrogenase (G6PD). Different procedures for the conditions for storage of red blood cells and the preparation of haemolysates were investigated. A total of 2170 samples of blood were taken from apparently healthy persons—1212 males and 958 females—from randomly selected villages and city centres in the southern part of Turkey. Analytical variation, intra-individual variation and inter-individual variation were 8·67%, 32·8% and 31·8%, respectively. The mean (SD) for G6PD was 8·6 (3·3) IU/gHb. The index of individuality, 1·03, showed that the reference intervals could be used for diagnostic purposes. Whole blood or a red cell pellet could be stored in physiological saline for one week at 4°C or −20° with little loss of activity. Two of three different procedures for the preparation of haemolysate gave data that showed no statistical difference and were equally satisfactory.
Calcium Metabolism following Renal Transplantation
Authors: Straffen Anne M , Carmichael DJS , Fairney Angela , Hulme B , Snell M 
Published: February 2014

Abnormalities of calcium homeostasis are a recognized feature of end-stage renal disease. The treatment of choice is renal transplantation, but this does not always result in normalization of the biochemical profile. Persistent hypercalcaemia is well documented and our study was undertaken to investigate the status of the calcium regulating hormones in renal patients post-transplantation. Serum calcium, parathyroid hormone, 1,25-dihydroxyvitamin D (1,25(OH)2D) and osteocalcin concentrations were measured in post-transplant patients. Twenty per cent of the patients had subnormal 1,25(OH)2D concentrations while 55% had biochemical evidence of hyperparathyroidism but only 5% were hypercalcaemic. Time elapsed since transplantation was not correlated with any of the analytes investigated and there was no relationship between persistent impairment of renal function and abnormalities of calcium homeostasis.
Quality Assessment of Urinary Organic Acid Analysis
Authors: Bonham J R , Downing M , Pollitt R J , Manning N J , Carpenter K H , Olpin S E , Allen J C , Worthy E 
Published: February 2014

The number of known inherited metabolic disorders resulting in an organic aciduria has increased steadily over the past two decades. Prompt and reliable detection is both clinically and technically demanding but is essential if appropriate treatment is to be undertaken. This is the first study of laboratory performance in the detection of these disorders to be undertaken in the UK. Some conditions were accurately identified by most laboratories: for example for maple syrup urine disease, 12 of 14 laboratories provided an appropriate response and medium chain acyl-CoA dehydrogenase deficiency was correctly identified by 15 of 17 laboratories. However, accuracy of detection was poorer for other conditions: for example, only eight of 17 laboratories detected tyrosinaemia type 1 and nine of 18 laboratories detected 4-hydroxybutyric aciduria. The strongest correlation with good performance was obtained by comparison with the extent of peak identification: r=0·62, P=0·002. The need for regular attendance at scientific symposia was also supported by a weaker positive correlation with the average score achieved, P=0·08. Evidence also suggested that some of the laboratories with a low workload performed less well. No significant difference in performance could be demonstrated between the 17 laboratories who used gas chromatography -mass spectrometry and the six participants who used gas chromatography alone.
An Improved Method for the Determination of Islet Amyloid Polypeptide Levels in Plasma
Authors: van Hulst K L , Hackeng W H L , Höppener J W M , van Jaarsveld B C , Nieuwenhuis M G , Blankenstein M A , Lips C J M 
Published: February 2014

We describe an improved method for the determination of islet amyloid polypeptide (IAPP) levels in plasma. Plasma is first extracted with acid-acetone, followed by a specific and sensitive radioimmunoassay (RIA) for IAPP using rabbit-anti-human-IAPP serum. Recovery of synthetic IAPP from plasma was 82±6% ( n = 16). Standard samples, prepared in ‘hormone-free’ serum, were also extracted with acid-acetone. Displacement curves of serially diluted acid-acetone extracted plasma samples were parallel to the standard curve. The lower detection limit of the RIA was 2·3 ± 0·1 fmol/sample ( n = 5). Intra-assay variations for IAPP concentrations of 4, 17 and 32 pM were 16·3% ( n = 10), 9·2% ( n = 10) and 6·2% ( n = 10); inter-assay variations were 35·9% ( n = 14), 19·9% ( n = 15) and 15·4% ( n = 15), respectively. Non-stimulated IAPP levels ranged from 2·4 to 12 pM (mean 6±4pM, n = 10) in healthy control subjects. IAPP was not detectable in type 1 (insulin-dependent) diabetic patients before and after glucagon administration. In type 2 (non-insulin-dependent) diabetic patients basal levels ranged from 2·2 to 14·5 pM and glucagon-stimulated levels ranged from 2·2 to 38·9 pM. The increase in IAPP varied from 0 to 24·4 pM. The anti-human-IAPP serum had full cross-reactivity with rat IAPP (= mouse IAPP). Transgenic mice overexpressing the human IAPP gene showed elevated plasma IAPP levels as compared to (non-transgenic) control mice. It is concluded that the method presented for the determination of IAPP in plasma is reliable and easy to perform, yielding reproducible results. The ability to measure plasma IAPP levels will help to elucidate the physiological function of IAPP as well as its pathophysiological role in type 2 diabetes mellitus.
On-Call Duties in Chemical Pathology: A Survey of Junior Medical Staff in the UK
Authors: Murphy M J , Paterson JR , Neithercut W D 
Published: February 2014

To ascertain the extent of variation in out-of-hours duties among trainees in chemical pathology in the UK questionnaires were sent to 81 junior medical staff in 1992. Replies were received from 63 (78%). Although most had participated in an advisory rota, only 41 (65%) had participated in an analytical rota. Nine (14%) had participated in specialist analytical rotas, while 13 (21%) had experience of multidisciplinary rotas and only eight (13%) had experience of rotas involving clinical responsibility. Only 10 (16%) regularly reviewed their work on call with their senior medical staff. There was no single method of requesting tests out of hours in the trainees' laboratories and there was also considerable variation with respect to the tests available out of hours. It is concluded that sufficient variation exists in the on-call experience gained by junior medical staff in chemical pathology to raise concern about the quality of training in out-of-hours work.
Interference Due to Lipaemia in Routine Photometric Analysis—Survey of an Underrated Problem
Authors: Brady J , O'Leary N 
Published: February 2014

Traditionally external quality assessment schemes (EQAS) distribute samples spectrally similar to a normal serum. This does not allow laboratories to assess the performance of their methods at measuring lipaemic samples. The Irish EQAS distributed a sample with a supplied lipid diluent. A sample of the same batch had previously been circulated as a normal distribution to obtain baseline values. Most analytes were affected by the lipaemia. The degree of interference was instrument/method dependent and a wide range of values was reported for each analyte: total protein 51–134 g/L (baseline 65 g/L); albumin 33–56 g/L (baseline 42 g/L); calcium 2·12–6·10 mmol/L (baseline 2·34 mmol/L); urate 38–1100μmol/L (baseline 195μmol/L); creatinine 6–199μmol/L (baseline 140μmol/L); glucose 4·2–9·5 mmol/L (baseline 4·8 mmol/L); total bilirubin 1–192μmol/L (baseline 36μmol/L); urea 1·1–8·1 mmol/L (baseline 3·8 mmol/L); aspartate aminotransferase (AST) 12–105 iu/L (baseline 44 iu/L); iron 4·3–107μmol/L (baseline 26·8μmol/L); inorganic phosphorus 1·12–4·96 mmol/L (baseline 1·59 mmol/L); and cholesterol 2·5–17·1 mmol/L (baseline 4·1 mmol/L). In situations where no clearing of the lipid occurs in the reagent, interference can be minimized by taking a sample blank reading or using a kinetic procedure. If clearing of the lipid does occur, time must be allowed for this to be completed before analytical readings are taken.
A New Enzymatic Method for the Determination of Inulin
Authors: Sugita O , Tomiyama Y , Matsuto T , Okada M , Gejyo F , Arakawa M , Takahashi S , Watazu Y , Kaneda N 
Published: February 2014

A new enzymatic method for the determination of inulin in plasma and urine, using inulase (EC 3.2.1.7), fructokinase (EC 2.7.1.4), phosphoglucoisomerase (EC 5.3.1.9) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) is described. The assay is based on the hydrolysis of inulin or Inutest (Inutest® which is the injectable form of inulin), by inulase and the determination of fructose released. The assay was linear up to 2 g/L of Inutest. The within-batch and between batch coefficients of variation were 2·3% and 2·2%, respectively. Recovery of added Inutest from plasma and urine was 98–102%. There was no interference from glucose (27·7 mmol/L), fructose (1·7 mmol/L) or mannose (1·7 mmol/L). When inulin clearance (using this method) and thiosulphate clearance were compared in 37 patients the inulin clearance was 9·3 mL/min (12%) lower than the thiosulphate clearance. We conclude that this enzymatic method is a simple and specific method.
Evaluation of an Enzyme-Immunometric Assay for Serum α-Glutathione S-Transferase
Authors: Rees Gareth W , Trull Andrew K , Doyle Sean 
Published: February 2014

A commercially available enzyme-immunometric assay for serum α-glutathione S-transferase (GST) was evaluated. Endogenous serum α-GST diluted linearly within the calibration range. However, we recommend that the sample and second antibody reagent are always added sequentially in the assay to avoid hook effect. Between-assay variability was below 7% across the calibration range and the upper limit of the reference range in adults ( n = 219) was 11 · 4 μg/L. Within-individual variability in serum α-GST concentrations measured over a 4–6 week period in 4 healthy adults was small. Serum α-GST concentrations did not change significantly 6 h after a therapeutic dose of paracetamol. Studies in two patients after liver transplantation showed that serum α-GST is a better discriminant of acute changes in liver function than conventional tests. Serum α-GST concentrations were unaffected by gross muscle damage, extra-hepatic inflammation, or haemolysis and thus appear to be more liver specific than transaminase activities. The effect of renal impairment on serum α-GST concentrations requires further investigation.