bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Analytical Aspects of the Immunochemical Determination of the Selectivity of Proteinuria
Authors: Beetham R. , Mills R. J. , Raine D. N. , White R. H. R.
Published: February 2014

The selectivity of proteinuria has been determined from the relative clearances of α1-acid glycoprotein, albumin, transferrin and IgG in 190 children and adolescents. The precision of the determination of selectivity (C.V. = 3%) is greater than that of the individual protein clearances determined by a double immunodiffusion method (C.V. = 13–22%). Neither sample storage for a limited period nor concentrating the urine affects the selectivity value significantly; serial determinations in one patient for 24 h showed no diurnal variation.

The effectiveness of selectivity in predicting the steroid response in the nephrotic syndrome was found to be slightly superior when determined from all four proteins than from transferrin and IgG alone. Inclusion of α2-macroglobulin relative clearance in the selectivity determination often significantly alters the value determined from the other four proteins alone. The reasons for this are discussed. Demonstration of α2M in urine which has not been concentrated, strongly suggests the presence of a structural glomerular lesion.
Recognition of the Mucopolysaccharidoses by Four Screening Tests, including a Refinement of the Albumin Turbidity Test, and Their Differentiation by Electrophoretic Separation of Urinary Glycosaminoglycans
Authors: Lewis P. W. , Raine D. N. , Kennedy J. F.
Published: February 2014

Urinary excretion of mucopolysaccharides by normal subjects and patients with a mucopolysaccharidosis has been assessed by four screening tests including two quantitative determinations. Inclusion of a urine blank has been shown to reduce the number of false positive results given by the bovine albumin turbidity test.

An electrophoretic technique has been developed and applied to urine concentrates. It has proved useful in the differential diagnosis of the mucopolysaccharidoses since four types are distinguished by characteristic glycosaminoglycan band patterns and another glycosaminoglycan pattern characterises two further types.
Inhibition and Activation of Human Lactate Dehydrogenase by Urea
Authors: McQueen M. J.
Published: February 2014

The degree of inhibition or activation at 37°C by urea of human lactate dehydrogenase isoenzymes has been established with pyruvate, 2-oxobutyrate, and hydroxypvruvate as substrates. Lactate dehydrogenase activation has been demonstrated in the presence of low concentrations of urea. The protective effect of urea against enzyme inhibition by increased substrate concentrations has also been confirmed. Clinical studies indicate that urea inhibition is a practical and potentially valuable tool in the assessment of LDH isoenzyme patterns at 37°C.
Continuous Flow Techniques for the Determination of Serum Calcium and the Simultaneous Determination of Calcium and Inorganic Phosphate in Serum and Urine
Authors: Brydon W. G.
Published: February 2014

The fluorometric method of Fingerhut et al. (1969) for the determination of serum calcium has been modified to approximately treble the sensitivity. Using only 120 μl of sample a method has been developed for the simultaneous determination of calcium and inorganic phosphate in serum and urine, the phosphate being measured by complexing phosphomolybdate with methyl green, a method developed by Van Belle (1970). Only a single dialysis stage is required, and reagents and sample can be delivered using an AutoAnalyzer Pump I. The techniques correlate well with other methods. Accuracy and precision data are presented.
An Off-Line Clinical Chemistry Computer System
Authors: Vitek P. , Chiu S. , Healy M. J. R. , Lucas D.
Published: February 2014

A low cost computer-based data processing system for a middle-size clinical chemistry laboratory is described. The emphasis is laid on organizing the laboratory work, minimizing the amount of clerical and arithmetic work undertaken by the technicians, and providing positive specimen identification.

Details of specimens arriving for analysis are input to the computer, which allocates laboratory numbers and constructs worksheets for the various chemical tests. The results are also input (off-line) to the machine, which brings together results of different tests on one specimen and prints out properly identified reports. The accumulated results are transferred to a large remote computer and stored there on an archives file.
Evaluation of Specific Protein Analysis in a Non-Teaching Hospital Laboratory
Authors: Salkie M. L. , McNeil Evelyn M.
Published: February 2014

A retrospective study has been made to assess the value of specific protein analysis in a routine laboratory. The use of cellulose acetate electrophoresis, immunoelectrophoresis, and single radial immunodiffusion has been discussed with reference to the source of the request for the investigation and the yield of abnormal results. A scheme for the investigation of abnormal proteins is presented with a discussion of the problem of diagnosing myeloma as distinct from identifying an abnormal protein. The occurrence of double-zones on Tri-Partigen plates (Hoechst Pharm.) may be an early indication of myeloma, but does occur in other conditions. Levels of immunoglobulins in the geriatric age group have been shown to be similar to that of non-geriatric adults. Specific protein analysis has been shown to be of limited value in rheumatoid arthritis.
A Semi-Automated Method for the Determination of Ammonia in Urine using the Nessler Reaction
Authors: Hartley T. F.
Published: February 2014

Species in urine which were likely to interfere with the determination of ammonia by Nesslerisation were adsorbed onto a precipitate of zinc hydroxide formed in situ in each sample. The ammonia concentrations in the subsequent supernatant solutions were measured using the Nessler method, adapted for use on a continuous flow analysis system. These measurements were made against a series of standards prepared from Analar grade ammonium chloride. The accuracy, reproducibility, and sensitivity of this adaptation were examined and were found to be within acceptable limits.
A Method for Quantitating Amylase and its Use in the Investigation of Various Body Fluids
Authors: Kipps Ann E. , Whitehead P. H.
Published: February 2014

A plate-diffusion technique for the quantitative assay of amylase in body fluids is described which is dependent on the incorporation of a soluble amylopectin-dye complex into agar. The technique correlates well with other established amylase assays, and has a coefficient of variation of 1.45 for amylase levels within the normal range for serum.

Normal levels of amylase in serum and urine are reported which agree with those recorded by previous workers, and in addition values of amylase in semen, saliva, and tears are quoted.
Assay of Serum Inorganic Phosphate without Deproteinisation: Automated and Manual Micromethods
Authors: Lawrence R.
Published: February 2014

Several current techniques for the determination of serum inorganic phosphate in the presence of proteins are shown to have important disadvantages. An improved manual micromethod is described in which proteins are kept in solution by the use of sodium lauryl sulphate and the phosphate determined by the molybdenum blue reaction. The procedure has been adapted for the Technicon AutoAnalyzer and the Vickers D-300 and M-300, and has been shown to give very good precision in routine use.
An Inexpensive System of Automated Flame Photometry of Serum Sodium and Potassium
Authors: Thomas M. I. , Saunders R. A.
Published: February 2014

An inexpensive automated flame photometry system has been produced by utilising an I.L. 143 flame photometer fitted with an analogue output connected to a sampler (AutoAnalyzer or other). The pump of the I.L. 144 dilutor is used to aspirate the sample and a variety of single or two pen recorders can be used to record the results at the rate of 60 specimens an hour.
IgG, IgA and IgM by Formylated Rocket Immunoelectrophoresis
Authors: Slater Linda
Published: February 2014

Formylated rocket electrophoresis has been investigated as a means of measuring the serum immunoglobulins IgG, IgA, and IgM. This procedure is simpler to carry out than carbamylation. Comparison of formylated rocket results with those from the automated immunoprecipitin (A.I.P.) system and single radial immunodiffusion (S.R.D.) gives correlation coefficients of 0.92 to 0.98 and reproducibility comparable with the A.I.P. system and better than S.R.D. The procedure is recommended for use in laboratories when the number of requests for immunoglobulins does not warrant a specific protein analyser.
The Indigenisation of Pathology
Authors: Mitchell F. L.
Published: February 2014

It is widely assumed that systems, equipment, and training evolved in the clinical laboratories of “advanced” countries from years of experience are universally applicable to the needs of all developing nations. This fallacy has led to a situation where the advance of medicine in many such countries is now retarded by a lack of laboratory facilities. There is an urgent need to investigate all aspects of this problem and develop answers specifically orientated to the needs of each situation.
γ-Glutamyitransferase in Breast Milk
Authors: Landon Michael
Published: February 2014

The activity of γ-glutamyltransferase was measured in a series of human breast milk samples collected during the first post natal week. All the samples showed considerable γ-glutamyltransferase activity. The mean level fell from 28.8 U/ml to 3.9 U/ml seven days later. There was a highly significant correlation between γ-glutamyltransferase and the protein content of the samples studied.
An Assessment of the Performance of the SMA 12/micro Autoanalyser in Clinical Use
Authors: Leonard J. V.
Published: February 2014

The performance of the SMA 12/micro autoanalyser in clinical use in a children's hospital is described. Details of the precision and accuracy over a period of 134 operating days are given, and some of the factors which influence the results are discussed. The slow operating speed and analytical difficulties on the sodium, potassium, and cholesterol channels made the analyser unsuitable for routine use in this laboratory.
Comparison of a Fluorimetric Method and a Competitive Protein Binding Assay Kit for the Determination of Plasma Hydroxycorticosteroids
Authors: Gore Marion , Lester Eva
Published: February 2014

A new competitive protein binding (C.P.B.) assay kit for the determination of plasma hydroxycorticosteroids which uses a gamma emitting isotope, selenium-75, to label the Cortisol was compared with a fluorimetric method in use in a routine laboratory. The mean plasma corticosteroid level in a group of 54 normal subjects was found to be lower with the C.P.B. kit than with the fluorimetric method. The correlation coefficient between the two methods in 131 specimens from healthy subjects and patients under investigation for pituitary or adrenocortical disorders was + 0.92. The precision of the two methods was similar.
Application of Analytical Methods to Automatic Analysers
Authors: Cook J. G. H.
Published: February 2014

In adapting methods for automatic analysers modifications to the chemistry may help to simplify machine design. These modifications are acceptable only if they do not adversely influence the accuracy and reproducibility of the method. The strict timing sequence which is ensured in automatic analysers, particularly of the discrete type, allows a simplification of some methods not possible in manual assays.
A Sampling Device for Septum-Sealed Blood Containers
Authors: Isaacs M. D. J. , Dunnett N. , Nicholson D. J. , Jenkins R. W.
Published: February 2014

The device described replaces the sampling probe of any automatic diluter. It enables septum-sealed blood vials to be sampled without exposing the blood to the atmosphere, and dispenses the blood into sealed reaction vials. The advantages are that loss of volatiles in the sample and exposure of operators to open blood containers are eliminated.
Blood Sampling Techniques for Lactate and Pyruvate Estimation: A Reappraisal
Authors: Braybrooke J. , Lloyd B. , Nattrass M. , Alberti K. G. M. M.
Published: February 2014

The effects of venestasis and hand exercise on antecubital vein blood lactate and pyruvate concentrations have been re-examined. The results show that venestasis for up to 5 min has no effect, while hand exercise for as little as 20 s causes a marked increase in blood lactate and pyruvate concentrations. The implications of these findings are discussed.
A Reference Range for Plasma Total Calcium Derived from a Study of Hospital Patients
Authors: Hooper J.
Published: February 2014

The normal ranges of plasma total calcium in male and female inpatients and outpatients in a district general hospital have been determined using the SMA PLUS (Technicon Instrument Company Ltd., Basingstoke, England), after selective sampling to exclude cases likely to have abnormal results both on clinical and on biochemical grounds. The 95% ranges were 2.15–2.60 mmol/l for inpatients and 2.25–2.65 mmol/l for outpatients.
An Accurate Method for the Determination of Inorganic Phosphate in Serum
Authors: Pickup J. F.
Published: February 2014

Cali's approach to accuracy is reviewed, and it is concluded that the main factor limiting its extension to analytes other than elements is the lack of suitable definitive methods of analysis. The work published on calcium, and work known to be under way on other elements, is based on the use of stable isotope dilution-mass spectrometry (I.D.M.S.) as the definitive technique.

This paper outlines the theoretical considerations involved in extending I.D.M.S. to the determination of molecules; in particular, exact equations for the calibration graph obtained by I.D.M.S. are developed, and special cases of practical significance are defined. It is concluded that in theory there is no reason why accurate results should not be realised. The determination of isotope ratios is central to the technique of I.D.M.S. The means available for such measurements are discussed, and it is concluded that adequate precision can be achieved with standard equipment.

To illustrate the application of I.D.M.S. to molecules the steps involved in an assay for inorganic phosphate are defined, and the protocol thus evolved is applied to specimens from the Wellcome Group Quality Control Programme. Although good correlation was found between I.D.M.S. results and the participants' mean results, there was a substantial bias. It is argued that this is a result of the difficulty of defining “inorganic phosphate” as a chemical entity. Some requirements for future work in this field are enumerated.
A Lipid and Lipoprotein Profile of Treated and Untreated Diabetics
Authors: Billimoria J. D. , Isaacs A. J. , Melki Kate
Published: February 2014

A group of 149 diabetics and 98 healthy subjects without evidence of diabetes or ischaemic heart disease were studied.

Untreated diabetics under 40 years old and 40 years of age and over showed statistically raised fasting serum turbidity, triglycerides, and raised β and pre-β lipoprotein levels but not raised cholesterol levels over the age and sex matched normal subjects. Further, some 63% of all diabetics showed a distinct split pre-β lipoprotein pattern as seen on polyacrylamide disc electrol-***phoresis as compared with 17% in the control group. Raised lecithin and phosphatidylethanolamine (PE) levels were found in male diabetics and raised PE levels in young diabetic women.

In patients under treatment with insulin, chlorpropamide, or phenformin the diabetes was well controlled in most cases, but these patients did not have significantly lower lipid levels. Diabetics on a low carbohydrate diet showed improvement in triglycerides and pre-β lipoprotein levels, but β lipoproteins were not lowered. It is suggested that diabetics may benefit by the inclusion of clofibrate in the treatment.
Some Ionic and Dilution Effects in the Measurement of Urinary Oestrogens in Pregnancy
Authors: Simkins A. , Worth H. G. J.
Published: February 2014

The estimation of oestrogen in aqueous solutions and pregnancy urines using an automated procedure is affected by the presence of certain ions, and by dilution. These effects have been studied by calculating regression equations from the values obtained with urines to which ions have been added with and without urine dilution. The results suggest that the ionic effect is chemical rather than physical and that there is no advantage in including a predilution step in the analysis. Other means of removing the ionic effects have so far proved unsuccessful.
Plasma Calcium Levels in Pregnant Asian Women
Authors: Polanska Nina , Dale R. A. , Wills M. R.
Published: February 2014

Plasma calcium, phosphorus, alkaline phosphatase, total protein, and albumin were measured during pregnancy in a group of Asian women living in the south of England and in a control group. The Asian women had slightly lower mean plasma calcium concentrations than the control group. Exposure of Asian women to sunshine appeared to be low, and it was inferred that they probably had little endogenous synthesis of cholecalciferol as a result. Both Asian and control subjects ingested similarly low amounts of vitamin D. The Asian women consumed greater amounts of phytate and vegetable fibres than the controls, and it is suggested that these substances may reduce absorption of insoluble lipids (including cholecalciferol) and calcium in a setting where the dietary intake and endogenous synthesis of vitamin D are already borderline for the subjects' requirements.
Bisalbuminaemia in a Central European Family
Authors: Donhoffer Hilda , Ludány Andrea , Kellermayer M. , Jobst K.
Published: February 2014

A slow bisalbuminaemia, the first case reported in Central Europe, was diagnosed in a mother and both her children. The alloalbumin was homogeneous on SDS-acrylamide electrophoresis.
Superoxide Dismutase (Erythrocuprein) and Free Radicals in Clinical Chemistry
Authors: Gutteridge J. M. C.
Published: February 2014

Erythrocuprein (superoxide dismutase) has recently been shown to have an enzymic function towards superoxide anions. The discovery of superoxide dismutase, its mode of action, and estimation are reviewed along with a brief introduction to oxygen activation and free-radical chemistry. The formation, activity, and destruction of oxygen free radicals in white blood cells, red blood cells, and subcellular particles are discussed, ( a) The production of superoxide anions by white cells during phagocytosis is thought to be advantageous for the overall bactericidal event. ( b) Normal red blood cells generate low levels of superoxide anions. Increased levels of free-radical production could play a significant role in accelerating cell ageing (haemolysis), ( c) Subcellular particles produce superoxide anions. These as well as organic peroxides have been implicated in drug hydroxylation reactions involving cytochrome P-450.
Comparison of a Gas Chromatographic and Colorimetric Method for the Determination of Plasma Paracetamol
Authors: Chambers Robin E. , Jones Ken
Published: February 2014

Plasma paracetamol levels have generally been determined either by gas chromatography (Stewart and Willis, 1975), which relies on complex equipment, or by spectrophotometry (Knepil, 1974), which can be time-consuming. The introduction by Glynn and Kendal (1975) of a simple colorimetric method based on the reaction of paracetamol with nitrous acid to give 2-nitro-4-acetamidophenol appears to have overcome these disadvantages, thereby providing a suitable procedure for the rapid measurement of plasma paracetamol in cases of overdose. The method was reported to be specific for paracetamol, no interference being caused either by the sulphate and glucuronide conjugates of paracetamol or by a large number of other commonly found drugs.

This communication presents the results of a study in which plasma paracetamol levels determined by the colorimetric method were compared with those determined by an established gas chromatographic technique.
A Study of Factors Influencing Continuous Flow Kinetics: The Use of Serum Calcium Estimation as a Model
Authors: Spencer Kevin
Published: February 2014

Previous studies of continuous flow kinetics have described an “AutoAnalyzer” peak in terms of two time constants, lag constant “a” and exponential constant “b”. Further investigations described here define some of the factors which affect these constants and hence peak shape and analytical performance.

This communication outlines the application of this information to the development of an automated method for the determination of serum calcium, having a carry-over of less than 1 % and an analytical rate greater than 100/hour. The instaneous colour reaction, simple hydraulics, removal of the dialysis step, and the use of an integral debubbling flow cell have enabled small kinetic constants to be achieved. Over a period of three months' routine use between-batch coefficient of variation (C.V.) was 1.4%.
Measurement of Ionised Calcium in Body Fluids—A Review
Authors: Robertson W. G.
Published: February 2014

This paper reviews the techniques available to the clinical biochemist for measuring ionised calcium concentrations in biological fluids with particular reference to serum. At present ionised calcium may be measured colorimetrically, using tetramethyl murexide, or potentiometrically, using a calcium ion-selective electrode. These techniques compare favourably in terms of precision with existing methods for measuring total calcium. Advantages of measuring ionised calcium in preference to total calcium are ( a) that there is no effect of venous occlusion or change of posture on the ionised fraction of the effect on total calcium, ( b) that ionised calcium is the physiologically active form of the element, and ( c) that the ionised calcium concentration is a more reliable indicator of the calcium status of patients in certain clinical conditions. The main problem in the measurement of ionised calcium is the marked dependence of the ionised fraction on the pH of the sample. Extreme care must be taken to avoid loss of CO2 or build-up of acid during the handling of the blood sample.
Assay of Parathyroid Hormone in Human Serum and its Uses
Authors: Woodhead J. S. , Walker D. A.
Published: February 2014

The assay of parathyroid hormone has contributed greatly to our understanding of calcium metabolism in health and disease. The most important clinical application of the assay is in the differential diagnosis of hypercalcaemia, which is an increasing clinical problem. PTH assays are of little or no value in the absence of other biochemical data, especially accurate determinations of plasma calcium and phosphate.
Development and Application of a Fully Automated Continuous Flow Radioimmunoassay System
Authors: Forrest Gordon C.
Published: February 2014

A fully automated, continuous flow radioimmunoassay system is described. The antibodies are covalently linked to a magnetic cellulose solid phase and separation of bound and free antigen is achieved by applying an external electromagnetic field. The bound fraction, after washing, is counted in a flow-through gamma counter chamber.

The system, employing AutoAnalyzer modules, is highly reproducible and allows assays to be performed without equilibrium being reached, and only 10 minutes' incubation time is required.

The method is universally applicable to the assay of ligands, either protein, hormone, or drug, and for obtaining information about binding proteins. A new approach to the latter has been developed and is illustrated by a fully automated thyroid hormone uptake test which gives better discrimination between normal and pathological states than existing assays.

The system operates at 30 samples/h and is characterised by the high precision, speed, and minimal carry-over which can be achieved.
Spline Function Analysis Applied to a Human Placental Lactogen Assay
Authors: Mosley J. , Bevan B. R.
Published: February 2014

A mathematical procedure for calculating radioimmunoassay calibration curves is described. The application of this method to a human placental lactogen assay is discussed, and the results obtained are compared with those from other methods of analysis.
Flow Cell Modification of a Filter Fluorimeter Producing Improved Throughput and Precision
Authors: Spencer K. , Sutherland I. T. , Price C. P.
Published: February 2014

A modification of a Corning-EEL 244 filter fluorimeter to take a Hellma fluoronephelometric flow cell is described, and the characteristics of a standard flow cell and the Hellma flow cell are compared by the use of a continuous flow fluorimetric calcein—calcium method. The study shows that by this modification a considerable improvement in precision, carryover, and throughput is possible. The kinetically better Hellma flow cell enables speeds in excess of 70 per hour to be achieved with carryover and precision better than that obtained at 40 per hour with the standard flow cell. Curve regeneration of signals using the Hellma flow cell can also be carried out, enabling a further increase in analytical rate to be obtained.
Differences in the Calcium Concentration of Serum and Plasma Initially and after Storage
Authors: Lester Eva , Varghese Z.
Published: February 2014

Calcium concentrations of plasma and serum in glass and plastic containers initially and after storage for up to 8 months at —20°C were compared. The mean initial calcium concentration of the plasma samples was 2.491 mmol/l and this was significantly higher than the mean serum concentration of 2.440 mmol/l. There were no significant differences in the mean calcium concentrations attributable to differences in glass or plastic as materials for storage containers for either serum or plasma. The mean calcium concentration of serum remained stable over the entire storage period, but that of the plasma samples fell significantly between one month and six months, with no further fall between six months and eight months.
Plasma Calcium in Acute Myocardial Infarction
Authors: Wiener K.
Published: February 2014

Plasma calcium concentrations were measured in 18 patients suffering from acute myocardial infarction. Estimations were performed for several days after admission to hospital and a fall in plasma calcium was observed in 13 cases. Plasma albumin levels also decreased over this period, and correction of plasma calcium values to a fixed albumin level removed the apparent tendency to hypocalcaemia in these patients. Three patients with myocardial ischaemia showed similar decreases in plasma calcium and albumin. The observed changes are probably related to confinement to bed.
Inactivation in Vitro of Lactate Dehydrogenase-5 in Blood
Authors: Qureshi A. R. , Wilkinson J. H.
Published: February 2014

During incubation with rabbit blood in vitro rabbit-muscle lactate dehydrogenase-5 was inactivated at a rate similar to that observed in vivo. By contrast plasma and plasma containing erythrocytes had no effect on the enzyme activity, but plasma containing leucocytes inactivated the enzyme at the same rate as whole blood. The results obtained support the concept that intravascular inactivation accounts for the disappearance of enzymes from the circulation.
The Estimation of Gold in Urine by Flameless Atomic Absorption Spectroscopy
Authors: Dunckley J. V. , Staynes F. A.
Published: February 2014

An atomic absorption method is described whereby the gold excreted in the urine of patients undergoing chrysotherapy can be estimated. Gold is precipitated as telluride, dissolved in aqua regia, and extracted into methyl isobutyl ketone for estimation by atomic absorption spectroscopy using graphite furnace atomization.
Pregnancy and Homocystinuria
Authors: Brenton D. P. , Cusworth D. C. , Biddle Susan A. , Garrod P. J. , Lasley Lorey
Published: February 2014

Ten children have been born to five parents (four female, one male) with cystathionine synthase deficient homocystinuria. All the patients were pyridoxine responsive. The children are well except for one with Down's syndrome. Eight of the 10 children have no homocystine in the blood or urine and must be heterozygotes. The other two have small amounts of homocystine, and their genetic status is uncertain. The results are encouraging with regard to pregnancy and its outcome, but it is emphasised that the results might be very different in patients who do not respond to pyridoxine and become pregnant having high plasma methionine and homocystine values.
Urinary Free 11-Hydroxycorticosteroid/Creatinine Ratios in Early Morning Urine Samples as an Index of Adrenal Function
Authors: Walker Michael S.
Published: February 2014

Urinary free 11-hydroxycorticosteroid/creatinine ratios were determined in early morning urine samples from 113 females (age range 20–45 years) and 65 males (age range 22–45 years). Basal values in normal subjects fluctuated between 5 and 55 μmol/mol creatinine. In four patients in whom Cushing's syndrome was diagnosed, urinary free 11-hydroxycorticosteroid/creatinine ratios were greater than 85 μmol/mol creatinine. Administration of dexamethasone (0.5 mg/q.i.d.) to nine normal laboratory staff for two days resulted in a suppression of the urinary free 11-hydroxycorticosteroid/creatinine ratio to less than 50% of the mean basal value in all cases. This degree of suppression did not occur in two cases of Cushing's syndrome due to adrenal tumours.
Determination of Serum Creatinine by Reaction with Methyl-3,5-Dinitrobenzoate in Methyl Sulfoxide
Authors: Sims Charles , Parekh Amritlal C.
Published: February 2014

Creatinine in serum is determined with a new reagent system consisting of methyl-3,5-dinitrobenzoate and tetramethyl ammonium hydroxide in 50% methyl sulfoxide. The method shows excellent correlation with manual and automated alkaline picrate procedures and has comparable sensitivity. The proposed method has advantages over the dinitrobenzoyl chloride assay system in terms of sensitivity, reagent stability and precision. The day-to-day coefficient of variation is 2.9–3.8%, while within day is 1.5–2.1%. The standard curve is linear beyond 20 mg/dl creatinine. Compared to the picrate method, the proposed assay is less than one half as susceptible to a combination of known interfering agents. Based on the present studies, it is recommended as an excellent alternative to the commonly used picrate procedures.
Determination of the Anticonvulsant Drug—Dipropyl Acetate (Epilim) in Human Plasma by Gas Chromatography
Authors: U-Schulz H. , Toseland P. A.
Published: February 2014

A relatively simple gas chromatographic procedure is proposed for the analysis of the drug dipropylacetic acid in plasma. The compound is chromatographed, as the free acid after ether extraction. Prior to concentration of the solvent the acid is converted to its potassium salt, then regenerated to the free acid immediately before analysis.
Regional Quality Control Survey of Blood-Gas Analysis
Authors: Minty Barbara D. , Nunn J. F.
Published: February 2014

We undertook an external quality control survey of blood-gas analysis in 16 laboratories at 13 hospitals. All samples were prepared in the laboratories under investigation by equilibration of blood or serum with gas mixtures of known composition. pH of serum was measured with no significant bias but with an SD of random error 0·026 pH units, which was almost twice the SD of the reference range (0·015). An acceptable random error (half SD of reference range) was not obtained in a longitudinal internal quality control survey although there were acceptable results for buffer pH in both field and internal surveys. Blood Po2 was measured with no significant bias but with SD of random error 1·38 kPa which reduced to 0·72 kPa by excluding one egregious result. The latter value was just over half of the SD of the reference range (1·2 kPa). Pco2 of blood was also measured without significant bias but with a much smaller SD of random error of 0·28 kPa (by excluding one egregious result), which was again just over half the SD of the reference range (0·51 kPa). Measurements of blood Po2 and Pco2 seem generally acceptable in relation to their respective reference ranges but measurements of pH were unsatisfactory in both internal and external trials.
A Simple, Rapid and Precise Automated Method for the Determination of T3-Uptake
Authors: Jennings R. D.
Published: February 2014

A method is described for the automation of the T3-uptake test using a discrete analyser. This enables 160 samples to be analysed in two hours at a cost of only 9p a sample. By making use of a simple correction procedure for differences in charcoal contact time and for radioactive carryover it is possible to get a within-batch precision of 2·5% and a between-batch precision of 4·6% for values within the normal range.
Serum Enzymes and Isoenzymes after Surgery
Authors: Krafft J. , Fink R. , Rosalki S. B.
Published: February 2014

Serum creatine kinase, aspartate transaminase, and hydroxybutyrate dehydrogenase activities were abnormal in 76, 50, and 28% respectively of 50 patients studied within 26 hours of surgery. No patient showed clinical evidence of myocardial infarction. Creatine kinase MB isoenzyme elevation, and lactate dehydrogenase LD1 activity greater than LD2 (LD1 > LD2) were infrequent (6 and 10% respectively). No patient showed the combination of transient MB isoenzyme elevation and LD1 > LD2, although their rare association without infarction after surgery is to be anticipated.
A Reassessment of 8-Anilino-1-Naphthalene Sulphonic Acid as a Thyroxine Binding Inhibitor in the Radioimmunoassay of Thyroxine
Authors: Evans S. E. , Burr W. A. , Hogan T. C.
Published: February 2014

The effectiveness of 8-anilino-1-naphthalene sulphonic acid (ANS) in the radioimmunoassay (RIA) of thyroxine (T4) as an inhibitor of the binding of T4 to serum T4-binding proteins is assessed. The optimum ANS concentration is dependent upon the antiserum and the method used for separating free and bound T4. If T4 binding to serum proteins is not completely inhibited, resin separation methods may yield low values, while polyethylene glycol and double-antibody methods may produce high values for T4 concentration. Even with optimum ANS concentration gross errors in measurement of T4 may occur in patients with high thyroxine-binding globulin (TBG) concentrations.
Determination of Cortisol in Human Plasma by Radioimmunoassay
Authors: Read G. F. , Fahmy Diana R. , Walker R. F.
Published: February 2014

A radioimmunoassay for plasma cortisol featuring the gamma-emitting radioligand 125I-iodohistamine, coupled to cortisol-3-(O-carboxymethyl)-oxime, is described. The new procedure retains much of the specificity associated with the use of anti-cortisol-3-BSA sera with tritium-labelled radioligands, and has the further advantages that running costs are lower and there is a greater potential for automation. Cortisol values obtained by this procedure agree well with those obtained by a published specific radioimmunoassay using the tritiated cortisol radioligand. Specificity of the procedure was checked by comparing values obtained with and without thin-layer chromatography purification: correlation was excellent (r = 0·96). Satisfactory levels of sensitivity, precision, and accuracy were obtained.
A Limited Protocol for Assessment of Within-Batch Performance of Multichannel Analysers
Authors: McLelland A. S. , Fleck A. , Burns R. F.
Published: February 2014

An experimental protocol is described to evaluate rapidly the performance of biochemical analysers. A trial in which this protocol was applied to 15 multichannel continuous-flow analysers is described and the results are discussed. Some consideration is given to the effects of applying a commonly-used drift correction procedure to the raw data, and values of within-batch standard deviation are proposed which may be useful in assessing performance.
Intraperson Variability
Authors: Morgan D. B.
Published: February 2014

summary In a person in a steady state the set of values obtained for a test carried out on a series of samples will show fluctuation about a value (the setting). In practice a single test value is usually taken as an estimate of the setting. The general consequences of this approximation are discussed in relation to the various uses of data in diagnosis, and illustrated for the common measurements of clinical chemistry. The magnitude of these consequences depends on the proportion of the total variation in a group of persons which is caused by these fluctuations in the person—within-person variation (Varwp). When the proportion is high the aim should be to reduce Varwp. When Varwp is high because of analytical error, then improved analytical technique or replicate analysis is required. Otherwise standardised techniques and conditions for venepuncture or, as a last resort, repeated samplings are necessary. These problems are discussed in relation to the detection of hypokalaemia.
Rapid Semiautomated Method for the Differential Determination of Urinary Catecholamines
Authors: Wainwright R. S.
Published: February 2014

Summary A semiautomated method is presented for the determination of adrenaline and noradrenaline by a combination of the trihydroxyindole procedure for total catecholamines and a new procedure for the specific direct determination of adrenaline without interference from noradrenaline at physiological levels. This new procedure involves the reaction of adrenaline with alkaline thiosemicarbazide to produce a fluorophor of acceptable stability for use in automated procedures. Its structure is as yet unknown. The within-batch standard deviation for the trihydroxyindole and alkaline thiosemicarbazide procedures respectively were 0005 μmol/24h at a concentration of 0·368 μmol/24h and 0·012 μmol/24h at a concentration of 0·133 μmol/24h. The between-batch standard deviations of the two procedures were respectively 0·018 μmol/24h at a concentration of 0·388 μmol/24h and 0·015 μmol/24h at a concentration of 0·111 μmol/24h. Normal ranges for urine are presented for 24 healthy ambulant laboratory staff. The total catecholamine concentration (calculated as adrenaline) was 0·452 ± 0·069 μmol/24h (SD), range 0·349–0·616 μmol/24h. Using the alkaline thiosemicarbazide procedure, the normal range which was determined for adrenaline was 0·100 ± 0·054 μmol/24h, range 0·022–0·207 μmol/24h. Noradrenaline calculated by difference was 0·355 ± 0·081 μmoL/24h, range 0·195–0·497 μmol/24h.
A Short Review of Techniques for the Localisation of γ-Glutamyl Transferase Isoenzymes after Electrophoresis
Authors: Wenham P. R. , Price C. P. , Sammons H. G.
Published: February 2014

Summary The development of a sensitive method for the localisation of γ-glutamyl transferase isoenzymes after electrophoresis on various media is described. Recommendations on final conditions are given for optimal concentrations of substrate, acceptor and buffer, and for pH of the reaction mixture. The reaction conditions are compared with other isoenzyme localisation techniques previously reported.
Assay of Tissue Free Cystine: Application to the Diagnosis of Cystinosis
Authors: Allard D. , Parvy PH. , Castets J. C. , Huang Y. , Kamoun P.
Published: February 2014

Summary A fast method for the determination of tissue free cystine is shown. Its usefulness for free cystine assays in leucocytes and muscle biopsies is discussed. The use of muscle biopsy as a means of diagnosing cystinosis is proposed.
A Comparison of Two Methods of Quality Control of pH, Pco2, and Po2 Measurements
Authors: Evans J. R.
Published: February 2014

Summary pH, Pco2, and Po2 measurements have been made over a three-week period on General Diagnostics Blood GAS Control Ampoules and on a tonometered buffer system. The latter seems adequate as a precision and accuracy control of pH, Pco2, and Po2 measurements in a single solution. The former seems adequate as a precision control of these measurements, but, on the particular batch provided, mean values need to be determined within the customer's laboratory.
Radioimmunoassay of Gastric Inhibitory Polypeptide
Authors: Morgan Linda M. , Morris Brian A. , Marks Vincent
Published: February 2014

Summary A radioimmunoassay for the measurement of gastric inhibitory polypeptide (GIP) in unextracted plasma in man has been developed using a rabbit antiserum raised against porcine GIP. Porcine GIP was employed also as standard and to produce a 125I-labelled tracer. The assay was able to distinguish 110 pg/ml GIP from zero in plasma samples. Negligible cross-reactivity was demonstrated with cholecystokinin, insulin, pancreatic polypeptide, glucagon, secretin, and vasoactive intestinal polypeptide. The mean overnight fasting plasma GIP level in 28 normal subjects was 203 pg/ml (range: undetectable—420 pg/ml). Plasma GIP levels rose, within 45 minutes of eating a mixed meal, to a mean level of 1573 pg/ml.
A Simple and Economical Method for the Radioimmunoassay of Cortisol in Serum
Authors: Morris R.
Published: February 2014

Summary A simple, economical method is described for the radioimmunoassay of cortisol in serum. Extraction is avoided by heating the diluted serum to inactivate cortisol-binding globulin. The radioimmunoassay is carried out in a single disposable scintillation vial without centrifugation. Free and bound steroid is separated by partition between ammonium sulphate solution and liquid scintillation fluid. Accuracy, precision and sensitivity are satisfactory. Normal ranges obtained are comparable to those obtained by other radioimmunoassay methods for cortisol.
Significance of Blood Cadmium Concentrations in Patients with Renal Disorders or Essential Hypertension and the Normal Population
Authors: Ward Roberta J. , Fisher Monica , Tellez-Yudilevich Marisol
Published: February 2014

Summary Cadmium concentrations in whole blood have been determined in normal control subjects, in patients with untreated essential hypertension or with treated essential hypertension, and in those with acute or chronic renal disorders. High cadmium concentrations were not found in the patients with untreated essential hypertension. Most tobacco smokers were found to have high blood cadmium concentrations. When the mean cadmium concentrations from each group of patients were compared with those of the control subjects no significant differences were found. When the four groups were divided into smokers and non-smokers, however, a significantly higher mean value was found for the non-smoking renal patients in comparison with the non-smoking normal subjects. The marked increases in blood cadmium concentration in the patients with renal disorders may be attributed to impaired excretion.
Scottish Immunoassay Support Service Quality Control Scheme for Thyroxine, Triiodothyronine, and Digoxin Assays: Analysis of First 18 Months' Experience
Authors: Ratcliffe Wendy A. , Logue F. C. , Ratcliffe J. G.
Published: February 2014

Summary Initial experience of the Scottish Immunoassay Support Service Quality Control scheme for thyroxine (T4), triiodothyronine (T3), and digoxin is analysed.

For T4, radioimmunoassay (RIA) methods gave values close to the all-method mean. Competitive protein binding (CPB) kits gave values significantly higher (by 12%) in one and lower (by 10%) in another, probably due to the extraction of interfering substances such as non-esterified fatty acids or thyroid hormone binding proteins. The range of between-batch precision of individual laboratories was 10·8–47·5% (mean 17·8%) over the clinically relevant range. It was particularly poor at levels below the lower limit of the normal range.

For T3 RIA, kit methods gave significantly higher values than independent methods although recovery of exogenous T3 was approximately quantitative with both. Cross reaction of T4 in T3 assays was insignificant. The range of between-batch precision for individual laboratories was 11·4–35·5% (mean 21·9%), and was poorest at levels of 1 nmol/l or less.

For digoxin RIA, Lanoxitest γ gave significantly higher values than other methods, and over-recovered exogenous digoxin. The range of between-batch precision was 13·8–35·2% (mean 21·6%), and was poorest at levels of 1 nmol/l or less.

The distribution of liquid human serum specimens at ambient temperature was satisfactory for quality control of T4, T3, and digoxin RIA but not for T4 by the Thyopac 4 method. Ox serum was unsuitable for certain T4 RIA methods.
Radioimmunoassay of Amitriptyline and Nortriptyline in Body Fluids
Authors: Mould G. P. , Stout G. , Aherne G. Wynne , Marks V.
Published: February 2014

Summary A radioimmunoassay for the measurement of amitriptyline and nortriptyline in serum, saliva, and urine is described. The sensitivity of the assay is such that 0·5 ng/ml of drug can be measured, although the assay does not distinguish between amitriptyline and nortriptyline. Other tricyclic compounds cross-react with the antiserum to varying degrees, but the metabolites of amitriptyline did not significantly cross-react. Total tricyclic compounds were detected in serum and saliva after single oral doses of amitriptyline, although the absorption was slow.
An On-Line Work Scheduling and Ward Requesting Pattern Information System
Authors: Undrill P. E. , Gibson P.
Published: February 2014

Summary The organisational efficiency of sample admission to the routine laboratory and the allocation to test methods has been improved by a scheduling system based on an on-line minicomputer. A flexible system has been constructed using multiple visual displays, which produce work allocation lists. Computer techniques have been developed which enable maximal use of the on-line system while retaining the general flexibility of high-level language coding, as implemented on an unsophisticated 12-bit processor. The file structure has been designed to provide cumulative information on the requesting patterns appropriate to any of the many sources of samples to thelaboratory, and to allow the automatic merging of worksheet and laboratory data, the latter being generated and transmitted from a second mini-computer system.
Concentrations of Organic Acids in the Urine of Healthy Newborn Children
Authors: Alm J. , Hagenfeldt L. , Larsson A.
Published: February 2014

Urine concentrations of organic acids were determined by a gas chromatographic technique in healthy, full-term neonates at the ages of 2 and 5 days. Significant reductions in the interindividual variation were obtained by relating the levels of organic acids to urine creatinine concentration or osmolality. Citrate was the predominant organic anion found. Urine concentrations of fumarate, 3-hydroxy-3-methylglutarate, adipate, and suberate decreased during the first week of life, and their concentrations were significantly intercorrelated. It is suggested that these findings reflect the predominantly fat-utilising, hyperketonaemic state during the first days of life. The urine concentrations of the aromatic end-products, p-hydroxyphenylacetate and hippurate, increased during the first week of life, probably as an effect of dietary factors.

It is concluded that analysis of intermediary organic acids in urine could be of value in the assessment of the metabolic state in neonates.
Optimal Conditions for the Estimation of Ammonium by the Berthelot Reaction
Authors: Gordon Sharon A. , Fleck A. , Bell Jean
Published: February 2014

A technique for optimising reagent concentrations on the AutoAnalyzer has been applied to the estimation of ammonia by the Berthelot reaction in the determination of urea and organic nitrogen. Comparison of the use of phenol and salicylate revealed that the optimum concentration of the latter is about four times that of the former. The optimum concentration of hypochlorite is five times greater with salicylate than with phenol, and for the catalyst, sodium nitroprusside, the factor is two. The precision obtained with the different methods is similar.