bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Glycosylated Haemoglobin in Normal, Newborn and Diabetic Saudi Arabs
Authors: Alayash A I , Dafallah A , Al-Husayni H , Al-Ali A K , Al-Qourain A , Saba M Ramzan , Wilson M T
Published: February 2014

Colorimetric determinations of glycosylated haemoglobin by the thiobarbituric acid method were carried out in normal adults ( n = 142), newly born infants of healthy mothers ( n = 81), and in a group of patients with diabetes mellitus ( n = 124). The glycosylated haemoglobin level in normal adult males was 4·9%, which is close to that reported for other populations. No correlation was found between age and the levels of glycosylated haemoglobin in males over 10 years old. However, the mean value for glycosylated haemoglobin in cord blood was 4·1%, significantly different from that of adults. The range values for glycosylated haemoglobin in diabetic patients was 7–19%. The mean value for glycosylated haemoglobin was 10·9%, similar to that established in other diabetic populations. Results of colorimetric determinations of glycosylated haemoglobin in the Saudi population compare well with other ethnic groups and, therefore, suggest no ethnic differences in glycosylated haemoglobin levels.
Measurement of Connective Tissue Parameters in Serum for Diagnosis and Follow-Up of Liver Fibrosis
Authors: Gressner A M
Published: February 2014

Hepatic fibrogenesis, i.e. activated synthesis and excessive intercellular deposition of connective tissue molecules (collagens, adhesive glycoproteins, proteoglycans) occurs in chronic alcoholic and viral liver injury and, less frequently, in some other conditions. The process may be monitored biochemically by the radioimmunoassay of some connective tissue molecules or their fragments and by the measurement of the activity of certain enzymes in serum. Currently, the radioimmunoassay of the aminoterminal propeptide of type III procollagen in serum reflects best the activity of liver fibrogenesis. The serum level of laminin, a high molecular weight basement membrane glycoprotein, was found to be correlated with an elevated portal venous pressure.
Determination of Erythrocyte Fatty Acids by Capillary Gas Liquid Chromatography
Authors: Taylor Andrew J , Pandov Harry I , Lawson Nigel
Published: February 2014

A capillary gas liquid chromatography method was established for the routine determination of fatty acid profiles from washed erythrocyte membranes. Only the five major fatty acids found in erythrocytes (palmitic, stearic, oleic, linoleic and arachidonic acids) had acceptable precision (CVs <10·0%) for use in establishing quantitative differences between groups of individuals. Reference values were established for the relative amounts of these five fatty acids in adults. Significant alterations in the relative concentrations of oleic and arachidonic acids were found after storage at +4°C for 24 h, which has important implications in the study of changes in erythrocyte fatty acids in cancer and diabetes.
Introduction of an Ion Selective Sodium and Potassium Analyser in a Paediatric Intensive Care Unit: Our Experience over a 3-Year Period
Authors: Mann S W , Green Anne
Published: February 2014

We describe our approach, policy and experience in establishing a sodium and potassium analyser for use by medical and laboratory staff in a satellite laboratory adjacent to a paediatric intensive care unit. The effects on patient care are difficult to quantify, but are felt to be beneficial. A reduction in ‘out of hours' laboratory workload and significant financial savings have been achieved.
Protein Interferes with Ionised Calcium Measurement at the Reference Electrode Liquid Junction
Authors: Payne R B , Jones D P
Published: February 2014

The ionised calcium concentration of sequential retentates prepared by ultrafiltration of a human control serum increased with increasing protein concentration when measured with both a Nova 2 and a Radiometer ICA1 analyser using their standard reference electrodes. In contrast, the ionised calcium in the same retentates fell slightly with increasing protein when the reference electrode liquid junctions of the instruments were changed from hypertonic to isotonic solutions, the values then paralleling those in the filtrates. Thus, the clinically significant positive relationship between ionised calcium and protein that has been reported with the Nova 2 and ICA1 analysers is almost certainly an effect of protein on the reference electrode liquid junction potential rather than a consequence of a Donnan effect on true ionised calcium distribution.
Assessment of an Enhanced Chemiluminescent Immunometric Assay for TSH in 1127 Patients
Authors: Squire C R , Gimlette T M D
Published: February 2014

An enhanced immunochcmiluminometric assay for serum TSH (‘Amerlite’. Amersham, Bucks, UK) was studied in 1127 patients in routine clinical practice to assess its value as a first-line test of thyroid status. Good correlation with clinical thyroid status was found in the untreated euthyroid patients, in the untreated hyperthyroid and hypothyroid patients, in pregnancy and in the sick euthyroid. However, a large proportion of clinically euthyroid patients with nodular goitre, as well as those treated by thyroidectomy, radioiodine or antithyroid drugs and those on replacement ***I-thyroxine showed TSH values outside the reference range. Therefore, additional tests are likely to be needed frequently in these categories.
Urinary Free Catecholamines—Diagnostic Application of an HPLC Technique to the Investigation of Neural Crest Tumours
Authors: Davidson D F
Published: February 2014

Experience in the use of an in-house urinary free catecholamine assay for the investigation of possible neural crest tumours in a District General Hospital laboratory is described. Elevated excretion of catecholamines and vanillylmandelic acid was found in a number of cases including phaeochromocytoma and neuroblastoma. These as well as several other situations in which elevated catecholamine and vanillylmandelic acid values were found are discussed.
A Simplified Thin-Layer Chromatography System for the Detection of Commonly Abused Basic Drugs
Authors: Blakesley John , Wood David , Howse Clive , Spencer-Peet John
Published: February 2014

A simple method for the detection of drugs of abuse and their metabolites in urine is described. By extraction of urine (20 mL) with a buffered ToxElut™ solid phase column all the commonly abused opioid drugs can be detected on a single thin-layer chromatography plate. Location of the spots is achieved by spraying the plate with iodoplatinate following acidification with dilute sulphuric acid. Sensitivity of the order of 1 mg/L is attained for most drugs.
Comparison of Serum Calcium Fractions during Haemodialysis and Peritoneal Dialysis
Authors: Kelly P M , Bending M R , Barron J L
Published: February 2014

Total, ultrafiltrable and ionised calcium concentrations were determined in anaerobic serum from healthy volunteers, patients immediately before and after haemodialysis and patients on continuous ambulatory peritoneal dialysis (CAPD). Protein-bound, complexed and albumin-corrected total calcium concentrations were calculated from the results. During haemodialysis, complexed calcium did not change, whereas the other fractions increased. For patients on CAPD, the total, ionised and protein-bound calcium results were frequently lower than the reference group, whereas the ultrafiltrable and albumin-corrected total calcium results were within or higher than the reference group. Albumin-corrected total calcium for all subjects correlated better with ultrafiltrable calcium than with ionised calcium. It was concluded that low ionised calcium concentrations found in CAPD patients may be related to low albumin concentrations, and the concentration of physiologically active calcium may be normal in these patients.
The Relative Merits of Acute Phase Proteins in the Recognition of Inflammatory Conditions
Authors: Calvin J , Neale G , Fotherby K J , Price C P
Published: February 2014

A study has been undertaken on the relative merits of a variety of acute phase proteins in the assessment of patients with inflammatory conditions. Five acute phase proteins (α1-antitrypsin, α1-antichymotrypsin, orosomucoid, haptoglobin and C-reactive protein) and the ESR were measured in 171 patients presenting to the gastroenterologists (gastrointestinal disease: 130, other disease: 41). Assessment of the sensitivity and specificity of the proteins and the ESR showed α1-antichymotrypsin to be the most sensitive test (95%) with specificity (81%) similar to the other acute phase proteins measured. Factors such as oestrogens, renal failure and genetic variants affected the value of α1-antitrypsin, orosomucoid and haptoglobin. In the routine protein laboratory the combination of a ‘short’ half-life and ‘long’ half-life protein is likely to offer the most useful screen for inflammation in samples obtained from a wide range of patients. The two acute phase proteins C-reactive protein and α1-antichymotrypsin fulfil these criteria.
An Immunoturbidimetric Method for the Measurement of Beta-2 Microglobulin in Serum and Plasma on a Centrifugal Analyser
Authors: Tillyer C R , Rawal Y
Published: February 2014

A simple immunoturbidimetric method for the measurement of beta-2 microglobulin in serum on a centrifugal analyser is described. The method detects beta-2 microglobulin in the range 0·4–16 mg/L with an estimated within-batch and between-batch coefficient of variation of 5–8·5% and 9%, respectively. The method correlated well with two ELISA methods.
The Effect of Storage Temperature and Physical State on the Performance of Antisera in Radioimmunoassay after Long-Term Storage
Authors: Middleton B A , Morgan L M , Aherne G W , Marks V
Published: February 2014

The performance in radioimmunoassay of four antisera after storage at temperatures ranging from −40°C to room temperature, in three physical states (frozen, liquid or freeze dried) was investigated over a 3-year period. No deterioration in antiserum performance in terms of precision and accuracy of quality control serum measurement or recovery of ligand was apparent under any of the storage conditions studied. Some lowering of titre became apparent in two of the antisera over the study period. Deterioration was most marked when antiserum was stored lyophilised at room temperature. Storage of antiserum frozen confers no advantage over storage at 4°C provided precautions are taken to minimise bacterial contamination when storing antiserum in liquid form.
Antenatal Detection of Placental Steroid Sulphatase Deficiency by Measurement of Urinary 16α-Hydroxydehydroepiandrosterone Sulphate
Authors: Wilmot R L , Mawson R J , Oakey R E
Published: February 2014

A simple gas chromatographic technique for the measurement of 16α-hydroxydehydroepiandrosterone sulphate in urine from pregnant women is described. An assessment was made of the effectiveness of the measurement of this oestriol precursor for the antenatal diagnosis of placental steroid sulphatase deficiency. Twenty-two patients whose pregnancies were complicated by subnormal oestrogen excretion for gestation were studied. In nine of these, where placental steroid sulphatase activity was found subsequently in vitro to be normal, the excretion of 16α-hydroxydehydroepiandrosterone sulphate was <27 μmol/24 h. In the remaining 13 patients, in whom postnatal in vitro assay demonstrated absence of placental steroid sulphatase activity, urinary excretion of 16α-hydroxydehydroepiandrosterone sulphate was 59–360 μmol/24 h. The excretion of this metabolite was below the limit of detection (20 μmol/24 h) in 30 uncomplicated pregnancies.

It is concluded that urinary excretion of 16α-hydroxydehydroepiandrosterone sulphate >50 μmol/day or a ratio of urinary 16α-hydroxydehydroepiandrosterone sulphate to urinary oestrogen >2·0 correctly identifies, before delivery, those pregnancies in which fetus and placenta are deficient in steroid sulphatase activity.
A Simple Enzymic Method for the Measurement of Magnesium in Serum and Urine on a Centrifugal Analyser
Authors: Tsang W M , Howell M J , Miller A L
Published: February 2014

A method is described based on a reaction that requires magnesium-ATP as a co-factor for the activity of hexokinase (HK), coupled with glucose 6-phosphate dehydrogenase (G6PDH). Glucose and NADP are converted to D-gluconolactone 6-phosphate and NADPH, respectively. The rate of increase in absorbance at 340 nm due to the formation of NADPH is proportional to the magnesium concentration in the sample. Magnesium levels in serum and urine measured by the enzymic method compared well with those obtained by atomic absorpton spectrometry.

The within-batch precisions were 1·4% and 1·5% for the enzymic method and the atomic absorption method, respectively for a quality assurance sample with a magnesium concentration of 2 mmol/L. The enzymic method is accurate (recoveries of added magnesium to serum samples are 101–102%), reproducible (between batch CV 2·8%), and rapid (23 samples may be measured in 10 min). Data on accuracy, precision and correlation for the enzymic and atomic absorption methods are presented.
Reactivation of Creatine Kinase Activity by Preincubation with Buffered NAC Diluent
Authors: Penny Alan F , Jennings Alison
Published: February 2014

We have shown that several commercial control sera containing reversibly inactivated creatine kinase are reactivated by pre-incubation in N-acetyl cysteine assay diluent. The increase in activity can proceed for up to 4 h. This reactivation is not seen in patients' sera even after storage for 14 days at −20°C, 7 days at 4°C, or 2 days at 20°C, during which time no loss of activity was evident. This study brings into question the validity of using consensus values to standardise enzyme assays.
Immunoturbidimetric Measurement of Serum Retinol-Binding Protein in Renal and Hepatic Disease
Authors: Bankson D D , Rifai N , Silverman L M
Published: February 2014

Serum retinol-binding protein (RBP), with a biological half-life of less than 12 h, is a useful indicator of liver or kidney dysfunction. An automated immunoturbidimetric assay for the measurement of RBP has been developed using the Cobas-BIO centrifugal analyser and commercially available materials. Serum samples with RBP concentrations as low as 3 mg/L were measured. Within-run and day-to-day imprecision were 3·7 and 5·7%, respectively. The reference range (mean±2SD) for 51 adults was 17 to 61 mg/L. Slight haemolysis of serum (haemoglobin 10 g/L) resulted in an apparent 8% reduction of RBP with greater interference at higher haemoglobin concentrations. However, bilirubin in concentrations up to 0·15 g/L did not interfere with RBP measurements. There was good correlation between immunoturbidimetry and a commercial radial immunodiffusion method. Serum RBP concentrations were decreased in liver disease and increased in renal failure.
Radioimmunoassay for 6-Sulphatoxymelatonin in Urine Using an Iodinated Tracer
Authors: Aldhous Margaret E , Arendt Josephine
Published: February 2014

A radioimmunoassay (RIA) for urinary 6-sulphatoxymelatonin (aMT6s) using an 125I-aMT6s tracer is described. Iodinated aMT6s used as the label was synthesised by direct iodination of aMT6s using 1,3,4,6 tetrachloro 3,6 diphenylglycouril as the oxidant. The assay shows low cross reactivity with related compounds. Serial dilutions of 1:250 and 1:125 diluted urine gave parallel displacement curves.

Comparison of the new RIA using 125I-aMT6s with the RIA using 3H-aMT6s label gave good correlation, as did comparison with a gas chromatography mass spectroscopy (GCMS) for total free and conjugated 6-hydroxymelatonin.
Deprecating the Diagnostic Significance of Free Thyroxine Levels in Human Serum
Authors: Al-Awqati M A , Hassan Mithal
Published: February 2014

Prime diagnostic importance has been postulated for the measurement of free thyroxine in human serum. During the past decade various innovative and routinely applicable techniques have been developed for its assay, and claims for their superior performance in clinical practice have subsequently been made. However, in our opinion, based on current literature concerning thyroxine metabolism together with basic information about the physicochemical characteristics that govern its intravascular distribution, it seems appropriate to indicate caution against overestimating the diagnostic sensitivity attributed to free thyroxine measurement irrespective of assay methodology and its conceptual elegance.
Elevated Free Androgen Index as an Indicator of Polycystic Ovaries in Oligomenorrhoea without Obesity or Hirsuties
Authors: Eden J A , Place J , Carter G D , Jones J , Alaghband-Zadeh J , Pawson M
Published: February 2014

A group of oligomenorrhoeic women without obesity or hirsuties was investigated with high-resolution ultrasound, laparoscopy and biochemical parameters. In this series, polycystic ovaries (PCO), as defined by ultrasound and laparoscopy, are a common cause of oligomenorrhoea in women without the classic symptoms, and were strongly associated with an elevated free androgen index (FAI). Despite an elevated FAI, these women were not hirsute, It would seem reasonable to include a FAI in the investigation of the oligomenorrhoeic woman, along with the more ‘standard’ tests, such as thyroid function and a prolactin level.
Biological Activity of Serum Prolactin in Patients with Primary Hypothyroidism
Authors: Smith Caroline R , Butler Joan , Norman Michael R
Published: February 2014

Prolactin bioactivity was measured in sera from 22 patients with primary hypothyroidism and 13 euthyroid control subjects and compared with estimates of immunoactivity given by radioimmunoassay. The Nb2 rat lymphoma cell assay was modified to improve specificity for prolactin and used to measure bioactivity. Results of serum prolactin levels obtained using the bioassay were closely correlated with radioimmunoassay results in both hypothyroid patients and control subjects. Mean bioactivity/immunoactivity ratios in patients were not significantly different from those in control subjects. Mean prolactin concentration measured by both assays was significantly higher in patients than control subjects. Serum prolactin in patients with primary hypothyroidism appears to have essentially normal bioactivity as measured in the Nb2 assay, in contrast with a report of major differences between activity in radioreceptor assay and RIA in hypothyroid patients.
Individual Free Fatty Acids and Lactate Uptake in the Human Heart during Severe Sepsis
Authors: Lefevre G , Dhainaut J F , Tallet F , Huyghebaert M F , Yonger J , Monsallier J F , Raichvarg D
Published: February 2014

Coronary haemodynamics and myocardial metabolism of non-esterified fatty acids (NEFA) and lactate were studied in 11 patients with severe sepsis, and compared to 10 control subjects. Coronary sinus blood flow was evaluated by thermodilution. Arterial and coronary sinus blood samples were collected for the measurement of lactate and total and individual NEFA concentrations both in septic and control patients. There was an increase in lactate and total NEFA arterial concentrations with a marked increase in palmitic and linolenic acids. The uptake of the main NEFA (C14:0 to C18:2) was significantly decreased. In the control group, individual NEFA uptake was proportional to their arterial concentrations. This relationship was not observed in patients with sepsis: there was no preferential extraction of any particular NEFA. Furthermore, in patients with sepsis, myocardial oxygen consumption did not correlate with NEFA, but only with lactate uptake. Alterations in NEFA uptake were found to be constant during severe sepsis and are consistent with major disturbances in myocardial metabolism.
Small Scale Sandwich Enzyme Immunoassay for Human Chorionic Gonadotropin Using a New Micro-Transferable Plastic Bead as Solid Phase
Authors: Ruan Ke-He , Ke Dan-Ru
Published: February 2014

This paper describes a highly sensitive small scale enzyme immunoassay for human chorionic gonadotropin (hCG) in pregnancy urine using a micro-transferable plastic bead (MTPB) as solid phase.

Results of the present method for determination of 40 samples of pregnancy urine correlated well with those of the commercial radioimmunoassay and a better precision was achieved. This solid phase method may be widely applied to the immunoassay of small volumes.
Urinary Excretion of HMMA in Children
Authors: Walters E G , Proctor D G , Elder G H , Walters G
Published: February 2014

In two centres urinary excretion of HMMA was measured in a total of 359 children, aged from birth to 17 years, who were suspected of having a neuroblastoma; the diagnosis was subsequently confirmed in 39. Measurements were made on 24 h urine samples in 246 children, and on random samples in a further 113.

The urinary excretion of HMMA relative to creatinine declined progressively with increasing age. After the age of four years the rate of decline was such that some age groups could be combined for statistical analysis. The range of values for each group was similar whether 24 h or random urine collections were used. It is concluded that the latter are adequate for the initial assessment of HMMA excretion.
Zinc Concentrations in Pure Populations of Peripheral Blood Neutrophils, Lymphocytes and Monocytes
Authors: Goode Helen F , Kelleher J , Walker B E
Published: February 2014

It is doubtful if the measurement of plasma or serum zinc is of value in assessing zinc status. Leucocyte zinc has been suggested as an alternative since it may be representative of tissue zinc stores; but in many studies poorly defined cell populations make interpretation difficult. This paper describes detailed techniques for the isolation and analysis of pure populations of neutrophils, lymphocytes and monocytes. Zinc concentrations (± 1SD) in normal subjects were 1·;26 ± 0·;27 nmol/mg protein, 1·;85 ± 0·;32 nmol/mg protein and 2·;58 ±0·;65 nmol/mg protein in neutrophils, lymphocytes and monocytes respectively. Fasting caused a significant decrease in neutrophil and lymphocyte zinc, and an increase in monocyte zinc. Supplementation of zinc-replete subjects with 135 mg zinc/day for 3 weeks had no significant effect on cellular zinc concentrations.
The Value of C-Reactive Protein in the Diagnosis of Intestinal Perforation in Typhoid Fever
Authors: Olubuyide I O , Brown N M , Higginson J , Whicher J T
Published: February 2014

Serum C-reactive protein concentrations were measured in 28 Nigerian patients with typhoid fever on presentation at hospital and at intervals thereafter. Five of the 28 (18%) were subsequently diagnosed as suffering from ileal perforation. These patients had concentrations of C-reactive protein during the first 24 h of admission which were significantly higher (mean = 229 mg/L) than those without perforation (mean = 91 mg/L). C-reactive protein may have a role in the prediction of early diagnosis of perforation in patients with typhoid fever.
A Bloodspot Androstenedione Assay Suitable for Home-Monitoring of Steroid Replacement Therapy in Congenital Adrenal Hyperplasia
Authors: Egan Sandra M , Betts P , Thomson S , Wallace A M , Wood P J
Published: February 2014

A bloodspot assay has been developed using an antiserum raised against androstenedione-3-carboxymethyloxime-bovine serum albumin (AD-3CMO-BSA) conjugate and 125I-AD-3CMO-histamine tracer. The method has a detection limit of 0·6 nmol/L blood and a working range from 0·6 to 40 nmol/L blood. The between-batch precision ranged from 8·4% to 23·3%. Bloodspot androstenedione (AD) concentrations were measured in 50 neonates (26 male, 24 female) and in 95 children (54 male, 41 female) aged 6 months to 18 years. No sex difference in concentrations was found in neonates, in pre-pubertal children up to 8 years of age, in pubertal children (males 8–16 years, females 8–14 years) or post-puberty. Bloodspot AD concentrations ranged from <0·6 to 2·7 nmol/L in neonates, <0·6 nmol/L in pre-pubertal children, 0·6–2·1 nmol/L in pubertal children and < 0·6–4·6 nmol/L post-puberty.

Daytime bloodspot profiles in 10 children on replacement therapy for congenital adrenal hyperplasia generally showed good correlation between 17α-hydroxyprogesterone and AD concentrations ( r = 0·928, P < 0·001). Bloodspot AD profiles have advantages over 17α-hydroxyprogesterone profiles for the assessment of the adequacy of glucocorticoid replacement therapy.
Comparison of Potassium ISFETs with the Radiometer KNA1 and the Corning 902 Ion Selective Electrode Analysers for Whole Blood Potassium Ion Estimation
Authors: Thompson John M , Emmett Christopher , Smith Stephen C H , Cramb Robert , Hutton Peter
Published: February 2014

Evaluation of the performance of potassium ion sensitive field effect transistors (K+ ISFETs), developed by Thorn EMI in a form suitable for mass production and for incorporation in ‘near the patient’ analysers, showed only very small constant and proportional biases against the Radiometer KNA1 and the Corning 902 for whole blood potassium ion estimation. Between batch imprecision tests with whole blood showed the K+ ISFET was comparable in performance to the Corning 902 but inferior to the Radiometer KNA1. The evaluation demonstrated that ISFET manufacturing technology has now reached a stage of development at which ISFETs should be considered seriously for use in clinical chemical analysers.
Is Intact PTH a Sensitive Biochemical Indicator of Deranged Calcium Homeostasis in Vitamin D Deficiency?
Authors: Ashby J P , Newman D J , Rinsler M G
Published: February 2014

Intact PTH was elevated in 38/40 Asians with reduced serum 25 hydroxyvitamin D [25(OH)D] including seven patients with normal serum calcium, phosphate and alkaline phosphatase. Changes in intact PTH were disproportionately greater than for other biochemical parameters, making it the most sensitive early indicator of deranged calcium homeostasis in vitamin D deficiency.
Alterations in Fructosamine and Glycated Albumin Levels during Childhood
Authors: Abe Fusae , Yano Mitsuyasu , Minami Yoshiko , Ueda Takashi , Chikakiyo Hirokazu , Miyamoto Naoki , Shirakawa Norihisa , Shima Kenji
Published: February 2014

Age-related changes in the blood concentrations of glycated proteins during childhood and adolescence were examined by measuring the blood fructosamine (FA), glycated albumin (GA), glucose levels and total serum protein levels in 611 healthy children (325 boys and 286 girls) aged 0–18 years old. These levels were compared with those of 130 healthy adults. GA was measured by a newly developed, highly precise method of high-performance liquid chromatography (inter-assay coefficient of variation, 4·9%). The FA values of all groups of up to 15 years old (grouped in two year age brackets) were significantly lower than those of adults. The mean serum concentrations of GA in infants up to four years old were also significantly lower than in adults. A slight but statistically significant positive correlation was found between age and values of FA ( r = 0·36, P < 0·001), but not of GA ( r = 0·04). Levels of total serum proteins showed a positive correlation with those of FA ( r = 0·47, P < 0·001) but a weak correlation with those of GA ( r=0·29). These results suggest that age should be taken into account when the FA levels of children and the GA values of infants are evaluated.
Total Amylase and Pancreatic Isoamylase in Serum and Urine: Considerations from Data on Biological Variation
Authors: Cummings Steven T , Fraser Callum G
Published: February 2014

The analytical, within-subject and between-subject components of variation were estimated for amylase activity and pancreatic isoamylase activity in serum measured using newer analytical methods. Desirable analytical imprecisions based on within-subject variation were CV ≤ 4·4% and CV ≤ 7·0%, respectively. Conventional population-based reference intervals were not useful because of marked individuality; clinical decision-making points should be derived from the desired sensitivity and specificity. Serial results must change more than about 30% and 40% respectively before significance (P ≤ 0·05) can be claimed.

Similar data on total amylase and pancreatic isoamylase activities in random and first morning urines showed that the use of conventional reference intervals was appropriate. Very large changes (> 100%) were required before a difference in serial results was significant. Calculation of the urine amylase/creatinine ratio appeared to confer no advantage.

Derivation of the ratio of pancreatic isoamylase to total amylase activity in serum or urine was unlikely to provide additional information of value in either diagnosis or monitoring.
The Reduction of Peripheral Insulin Concentrations in Obese Subjects following a Hypocaloric Diet: Reduced Pancreatic Secretion or Increased Hepatic Extraction?
Authors: Gama R , Marks V
Published: February 2014

The fasting hyperinsulinaemia characteristic of obesity is due to pancreatic hypersecretion and is accompanied by a corresponding increase in plasma C-peptide concentrations. The exaggerated plasma insulin and C-peptide responses to oral glucose in obese subjects which is greater for insulin than C-peptide suggests that the stimulated hyperinsulinaemia is due to both pancreatic hypersecretion and decreased fractional hepatic extraction of insulin. In obese subjects fasting and stimulated insulin concentrations, but not those of C-peptide, are lower after 3 weeks of energy restriction than before it. This reduction in fasting and stimulated insulin levels is, therefore, due to an increase in the fractional extraction of insulin by the liver rather than to a reduction in pancreatic secretion as had previously been supposed.
A Computer Program to Determine Diagnostic Decision Thresholds and Likelihood Ratios Illustrated with Aspartate Aminotransferase Activities after a Myocardial Infarction
Authors: Pellar Thomas G , Galbraith Linda V , Leung Fred Y , Henderson A Ralph
Published: February 2014

We describe an enhancement of our earlier computer program which allows calculation of decision thresholds, sensitivity and specificity, and likelihood ratios of negative and positive test results for any chosen value of sensitivity or specificity. The program will also plot continuous receiver operating characteristic and decision level curves which permit examination of the contours created by using all the available data. We illustrate the value of these routines by showing that the sensitivity and specificity of serum aspartate aminotransferase changes during the course of a myocardial infarction.
Erythrocyte Membrane Stearic Acid : Oleic Acid Ratios in Colorectal Cancer Using Tube Capillary Column Gas Liquid Chromatography
Authors: Neoptolemos J P , Thomas B S
Published: February 2014

Erythrocyte fatty acids were measured in 32 patients with colorectal cancer (four with recurrent disease), four patients with large colorectal adenomas, and 42 hospitalised patients without cancer. No significant differences were found with respect to any of the fatty acids between these groups. In particular there was no difference between the erythrocyte stearic acid : oleic acid ratios (mean ± SD) between the cancer cases (1·07 ± 0·31) and the control cases (1·09 ± 0·31, 2-tailed Mann-Whitney U test). No difference in this ratio was observed with respect to age or sex and in the case of colorectal cancer, to the Dukes' stage, degree of tumour differentiation, or recurrence. A significant correlation was found between stearic acid concentrations in plasma and erythrocytes from fasting invididuals ( r = 0·477, n = 24, P < 0·05).

This study provides further evidence that the erythrocyte stearic acid : oleic acid ratio is of no value for diagnosing primary or recurrent colorectal cancer.
Mucosal Digestion Studies of Whole Gliadin Fractions in Coeliac Disease
Authors: Cornell Hugh J
Published: February 2014

Wheat gliadin was chromatographed on carboxymethyl cellulose and the major fractions (α-, β- and γ-gliadin) digested with pepsin, trypsin and pancreatin. The digests from each fraction were chromatographed on SP Sephadex and the fractions corresponding to the one previously shown to be toxic by oral feeding tests (fraction 9) were incubated with homogenates of small intestinal mucosa from children with coeliac disease in remission and from normal children. Electrophoretic patterns of the coeliac mucosal digests of fraction 9 from the α-, β- and γ-gliadin fractions all showed that appreciable amounts of undigested peptides were present in each of the three digests. In contrast, patterns of all digests prepared using normal mucosa showed only small amounts of undigested peptides. The results suggest that all three of these whole gliadin fractions contain substances which may be causative agents in coeliac disease.
ACTH Adrenal Cell Bioassay: Improved Sensitivity (12 ng/L) Achieved by Immunoextraction of Acth from Human Plasma by a Monoclonal Antibody
Authors: Mitchell R , Lambert A , Crosby S R , White A , Robertson W R
Published: February 2014

We have previously reported a bioassay for human plasma ACTH based upon trypsin dispersed guinea-pig adrenal cells which was sensitive to 100 ng/L ACTH in unextracted human plasma when measured against human pituitary ACTH (1–39) standard 74/555. We now present a bioassay of increased sensitivity (12 ng/L) which incorporates three major changes. The trypsin/trypsin inhibitor step in the cell dispersion protocol has been replaced with collagenase, donor calf serum (3%) has been incorporated into the standard curve and ACTH has been extracted from human plasma and dilutions of standard hormone by a sephacryl bound monoclonal antibody (2A3) directed towards the 25–39 sequence. The extracted standard curve has a detection limit of 6 ng/L and the cells can tolerate up to 50% plasma equivalent concentration. Thus, the improved assay has a detection limit of 12 ng/L ACTH in plasma. The assay can now measure bioactive plasma ACTH levels reliably in the normal range.
Changes in Size and Zinc Protoporphyrin/Haemoglobin Ratio in Red Cells of Infants during the First Months of Life
Authors: Bartels P C , Helleman P W , Soons J B J
Published: February 2014

A longitudinal investigation of changes in red blood cell (RBC) size distribution and zinc protoporphyrin/haemoglobin (ZPP/Hb) ratio was performed.

In the course of the first few weeks after birth RBC size distribution histograms show a loss of macrocytic RBCs demonstrated by a rapid decrease of the fraction of macrocytes, whereas the degree of RBC volume dispersion decreases simultaneously. Within this period a significant change in the fraction of microcytes was not observed. At about 6 months of age, a marked shift of RBC size distribution histograms towards lower volumes occurs. Concomitant with the lower MCV values, the values for the absolute distribution width at half peak height (ADW0.5) also showed an obvious decrease.

At birth, ZPP/Hb ratios are about three times higher than those of adult subjects and decrease slowly during infancy. This suggests that iron deficiency is unlikely in the first months of life.
An Automated Assay of Glycogen Phosphorylase in the Direction of Phosphorolysis
Authors: Schreiber William E , Bowling Sheila
Published: February 2014

We have developed a rapid, automated assay for glycogen phosphorylase that measures the degradative reaction. The substrate contains higher concentrations of phosphate and AMP than other methods, and the enzyme is preincubated with the substrate before adding phosphate to start the reaction. These modifications improve the activity and linearity of the assay. The new assay compares favourably with a standard phosphorylase assay in the synthetic direction and is linear to 500 U/L. We have used this assay to measure phosphorylase activity in human tissue samples and muscle biopsy specimens.
Laboratory Instrument Evaluation Using a Personal Computer
Authors: Wootton Andrew M , Stringer Malcolm
Published: February 2014

A system in which data from multichannel biochemical analysers is downloaded to a personal computer using a communications package is described. BASIC programs were developed to format the data into a file structure suitable for importing into a commercial statistics software package. This allowed statistical comparisons to be made of patient data obtained from different instruments and facilitated evaluation of these instruments. Using this technique, many hundreds of patient results may be compared without requiring the data to be keyed into a computer. The techniques and programs used are described to show that these facilities can be developed by laboratory scientists with only rudimentary computer programming skills.
The Usefulness of Faecal Haemoglobin, Albumin and α-1-Antitrypsin in the Detection of Gastrointestinal Bleeding
Authors: Morrow Robert J , Lawson Nigel , Hussaini Syed H , Asquith Peter
Published: February 2014

A pilot study was undertaken to find out whether faecal haemoglobin, albumin and α-1-antitrypsin from patients with gastrointestinal disorders could distinguish active bleeders from non-active bleeders and healthy volunteers. Alpha-1-antitrypsin is not as readily degraded by endogenous and bacterial breakdown as haemoglobin and albumin and consequently could be a better marker for occult bleeding.
Quality Goals for Hormone Testing
Authors: Ricós C. , Arbós M A
Published: February 2014

Estimates of intra-individual biological variation in normal subjects have been made for 17 hormones commonly measured for diagnostic purposes and the results have been compared with state-of-the-art analytical imprecision data. The implications of using these results for setting goals for analytical performance are discussed.
Development of a Heating Device for Sampling Arterialized Venous Blood from a Hand Vein
Authors: Zello Gordon A , Smith John M , Pencharz Paul B , Ball Ronald O
Published: February 2014

A practical and safe heating device for sampling arterialized venous blood from a hand vein was constructed and tested under experimental conditions. Blood chemistry values (pH, pCO2, pO2 and O2 saturation) were measured in nine individuals from blood sampled from an antecubital vein and a hand vein, as well as from a hand vein that had been heated in the handwarmer. Only blood sampled from the heated hand vein gave blood gas values that were consistently in the arterial range. Mean blood gas values were 38.0 ± 2.5 mmHg, 79.8 ± 6.8 mmHg and 95.7 ± 0.9% for pCO2, pO2 and O2 saturation, respectively, for blood sampled from the heated hand vein. No significant difference (P > 0.05) was evident in blood gas values whether blood was sampled 15, 30, 45, 60, 75 or 90 min after placing the hand in the heated handwarmer. The handwarmer enables arterialized venous blood sampling after 15 min of warming and is safe to use in any experimental or clinical situation where sampling from an artery is impractical.
Rapid Measurement of Basic Drugs in Blood Applied to Clinical and Forensic Toxicology
Authors: Dawling Sheila , Ward Neil , Essex Edward G , Widdop Brian
Published: February 2014

A gas chromatographic method is presented to measure blood, serum or plasma concentrations of more than 40 basic drugs. The sensitivity is 0·05 mg/L or less, which represents medium-high therapeutic and overdose concentrations, and in many instances the major active metabolites are also quantified. The paper describes a single step extraction from basic solution into n-butyl acetate containing maprotiline internal standard. Disposable glass tubes are used, with direct chromatography of the upper organic layer. GLC analysis is conducted for 10 min isothermally on a packed column (3% SP2250) with nitrogen-phosphorus detection. The coefficient of variation (CV) of the assay is between 2% and 5%, and data on the reproducibility of retention times are presented.
A Rapid Horizontal TLC Method for Detecting Drugs of Abuse
Authors: Wolff K , Sanderson M J , Hay A W M
Published: February 2014

We present a rapid, low-cost method for detecting opioids, cocaine and amphetamine in the urine of drug abusers. Rapid solid phase extraction of 2 mL of urine using octadecylsilane cartridges (Bond Elut C18) concentrates compounds of interest (including the polar metabolite of cocaine, benzoylecgonine), in a small volume of methanol, which is easily dried down. Four microlitres of aliquots of samples and standards are spotted on to 5 cm square polyester-backed silica gel plates, and developed (8–10 min) in a Desaga H-Chamber. Rf values of all relevant compounds are presented for two mobile phases using an iodoplatinate spray. The sensitivity of the method is not the same for all drugs but is always at least 1 µg/mL urine. A number of investigations can be performed on a single extract from 2 mL of urine including confirmatory tests using different solvent systems or sprays.
Basal Serum Dehydroepiandrosterone Sulphate Concentration Does Not Predict the Cortisol Response to Provocative Testing
Authors: Littley M D , Pollock A , Kane J , Shalet S M
Published: February 2014

The concentration of dehydroepiandrosterone sulphate (DHEAS) was measured in the plasma of 104 patients aged 16–78 years (48 men) undergoing routine assessment of anterior pituitary reserve. A fasting plasma sample was collected at 0900 h on the same day that either an insulin tolerance test or a glucagon stimulation test was performed. Serum cortisol, DHEAS and prolactin were measured by radioimmunoassay. DHEAS levels between 0·5 and 14 nmol/L were significantly but negatively correlated with age but there was no significant correlation with basal cortisol, maximum stimulated cortisol, the increment in cortisol or basal prolactin. The correlation of DHEAS with age was also observed when results for women were analysed separately but this did not hold for men. For male and female results separately, there was again no correlation of basal DHEAS with basal cortisol, maximum stimulated cortisol, increment of cortisol or basal prolactin.

The age and sex related reference range and other factors affecting basal DHEAS concentration make it a cumbersome and unreliable measure of hypothalamic-pituitary-adrenal axis reserve.
The Reproducibility of Bone-Related Biochemical Variables in Postmenopausal Women
Authors: Morris Howard A , Wishart Judith M , Horowitz Michael , Need Allan G , Nordin B E Christopher
Published: February 2014

Seventeen measured and derived bone-related biochemical variables were determined in 60 postmenopausal women on two occasions from 1 to 35 months apart. The coefficients of determination ( r2) between the first and second observations were highly significant in respect of all measured and calculated variables except for anion gap, calculated complexed calcium, fasting urinary sodium:creatinine ratio and urinary phosphate:creatinine ratio. The variables with coefficients of determination which ranked highest include plasma alkaline phosphatase, albumin, globulins, calculated ionized calcium and fasting urinary corrected calcium:creatinine and hydroxyproline: creatinine ratios. They also showed marked individuality suggesting that changes within the conventional population based reference range possibly indicate significant physiological changes in metabolism. The critical difference for two results to be significantly different ( P < 0·05) was calculated from the total variation for each variable. We conclude that most of the measured and derived bone-related biochemical variables in fasting plasma and urine samples are sufficiently reproducible in postmenopausal women to be clinically and physiologically meaningful but that urinary sodium and phosphate are inconstant and probably dependent on the previous day's dietary intake.
A Review of the Role of Established Tumour Markers
Authors: Beastall G H , Cook B , Rustin G J S , Jennings J
Published: February 2014

Increasing numbers of commercial assays for the established tumour markers are available which are capable of excellent analytical performance. Whilst all these assays are useful as research tools, their clinical value is more limited and should be appreciated before any decision is taken to offer a tumour marker assay service.

Calcitonin (medullary carcinoma of thyroid), alphafetoprotein (hepatoma) and human chorionic gonadotrophin (choriocarcinoma) are the only tumour markers that can be used for screening for malignancy in high risk populations. Hormones, paraproteins, alphafetoprotein, human chorionic gonadotrophin and prostate specific antigen are valuable in establishing the diagnosis of certain tumour types. Alphafetoprotein and human chorionic gonadotrophin concentrations at the time of diagnosis are of value in predicting prognosis in specific tumour types. Although their sensitivity for a particular tumour type may be poor, most tumour markers can be used for monitoring the therapy and follow-up of selected marker positive patients.

Optimal clinical results of the management of patients with malignancy are usually obtained by specialist centres, and laboratory tumour marker services should be established so that they are appropriate to local oncology specialities.
Elevated Serum and Urine Sialic Acid Levels in Renal Diseases
Authors: Özben Tomris
Published: February 2014

Total sialic acid (TSA) and lipid-associated sialic acid (LASA) concentrations were found to be significantly elevated in the sera of patients with chronic glomerulonephritis (CGN) and those with chronic renal failure (CRF) who were maintained on haemodialysis. The reference values for TSA and LASA were determined in the sera of 60 healthy subjects (33 males and 27 females) and showed no significant dependence on age and sex. No correlation existed between the TSA and LASA values, nor between TSA and LASA and the serum BUN and creatinine values in the patients and controls. A large amount of bound sialic acids was excreted in the urine of both groups of patients, although the serum sialic acid levels were increased.
Use of a Silver-Enhanced Gold-Labelled Immunoassay for Detection of Antibodies to the Human Immunodeficiency Virus in Whole Blood Samples
Authors: Rocks Bernard F , Patel Nishith , Bailey M Philip
Published: February 2014

A silver-enhanced gold-labelled immunosorbent assay (SEGLISA) for the detection of antibodies to the immunodeficiency virus (HIV) in whole-blood samples is described. This new non-isotopic, non-enzymic immunoassay incorporates use of solid phase viral antigens which bind any HIV antibodies present in the test sample. The antigen/antibody complex is then detected by gold-labelled anti human immunoglobulin G (IgG) followed by silver amplification. We found that whole blood samples give false positives when using a horseradish peroxidase label, whereas the SEGLISA correctly identified 50 HIV antibody positive samples and 50 HIV antibody negative samples when using whole blood. The use of whole blood collected on filter paper is also described. The SEGLISA has good precision (CV = 7·5 %) and sensitivity.
A Two-Site Immunoradiometric Assay for Pth(1–84) Using N and C Terminal Specific Monoclonal Antibodies
Authors: Logue F C , Perry B , Chapman R S , Milne I , James K , Beastall G H
Published: February 2014

We report the development of a two-site immunoradiometric assay for PTH(1–84) based on two site-specific monoclonal antibodies—3B3 (radiolabelled antibody) specific for PTH(1–34) and ESQ1 (on solid phase) specific for PTH(74–84). Antibody 3B3 is sensitive to the oxidation of the methionine residues in PTH(1–34) therefore hydrogen peroxide (0·1 M) is added to the incubation mixture. Validation studies confirm quantitative recovery of both oxidized and reduced PTH(1–84). The assay has a minimum detection limit of 0·5 pmol/L and a range of 1·5–250 pmol/L with an intra-assay CV of less than 10% (2·8–250 pmol/L less than 5% CV). Studies on clinical samples indicate good discrimination between normal subjects (mean 2·21; range 1·0–5·0 pmol/L) and patients with primary hyperparathyroidism (mean 21·0; range 5·8–100 pmol/L) who in turn are well separated from patients with hypercalcaemia of malignancy (14/18 < 0·5 pmol/L).