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L J Russell

Publications and source records attributed to L J Russell.

29 records · Page 2Linked to original sources
PubMed1988

Plasma sodium and potassium measurement: minimising ISE-flame differences using specimens from patients.

Experience in clinical chemistry of direct reading ion-selective electrode analysers for the measurement of plasma Na+ and K+ concentrations has shown that the results obtained on any specimen may vary significantly from one make of instrument to another. To overcome these differences, the European Working Group on ISEs of the IFCC Expert Panel on pH, Blood Gases and Electrolytes have proposed that instruments should be standardised to report Na+ and K+ concentrations in undiluted plasma to agree with flame emission spectrometry in samples with normal plasma water bicarbonate concentrations and normal pH. In designing and setting the calibration of a new ISE analyser for Na+ and K+, the Corning 614, the manufacturer has attempted to satisfy this proposal using a large number of specimens obtained from patients. This paper presents details of the procedure used and the results of an independent evaluation of its validity in routine clinical practice.

Electrodes↗
PubMed1986

The commercialisation of sensor technology in clinical chemistry: an outline of the potential difficulties.

Despite the numerous examples in the research literature of the potential application of biosensors in clinical chemistry, very few have reached commercialisation. Many pitfalls await the potential manufacturer of bioprobes in clinical chemistry and key areas which require substantial development are: reproducibility of sensor manufacture; interaction of the sensor with appropriate hardware; evaluation and customer perception. This paper discusses and illustrates these problems with examples taken from the recent introduction of ion-selective electrode analysers in regular clinical use. Many similar problems are envisaged for the commercialisation of biosensors and extensive collaboration is essential between researchers, manufacturers and users to overcome the difficulties.

Biotechnology↗
PubMed1985

Ion-selective electrode technology: an overview.

Diluting a sample before analysis, as is required by both flame photometry and indirect reading ISE analysers, gives less relevant analytical results than measuring an undiluted sample directly. This is because dilution masks the impact that protein and lipids exert on the true activity of an ion in a clinical sample. Measuring a sample directly without dilution enables only those ions which are not bound to other materials, e.g. other ions or proteins, to be detected. The levels of these free ions are more likely to reflect true physiological status than analysis of both free and bound ions. Measuring a sample of whole blood directly without dilution can only be performed accurately if the ISE analyser reference junction is unaffected by changes in haematocrit. Calibrant compositions should be of an ionic strength similar to that of physiological samples. Residual liquid junction potentials between calibrants and samples should be minimised by careful design of the reference electrode.

Autoanalysis↗
PubMed1984

In utero brain destruction resulting in collapse of the fetal skull, microcephaly, scalp rugae, and neurologic impairment: the fetal brain disruption sequence.

Three infants are reported with a recognizable pattern of defects consisting of severe microcephaly, overlapping sutures, prominence of the occipital bone, and scalp rugae. This condition, which we think represents microhydranencephaly, appears to be produced by partial brain destruction during the second or third trimester, diminution in intracranial hydrostatic pressure, and subsequent collapse of the fetal skull. Several different causes for this condition have been suggested including partial disruption of the blood supply to the brain and prenatal viral infection.

Adult↗
PubMed1984

New ways with old ions.

Explore the source record for details and available documents.

Chemistry Techniques, Analytical↗
PubMed1981

The axial mesodermal dysplasia spectrum.

Features of both the Goldenhar and the caudal regression syndromes were found in the patient described. A search of the literature revealed two other patients having both conditions. However, a number of other individuals have been reported with Goldenhar or related syndromes who have malformations in the caudal region or, conversely, who have the caudal regression syndrome and possess cranial anomalies. Possible explanations for the commonality of malformations seen in these syndromes are presented and discussed. It is suggested that the term, "axial mesodermal dysplasia spectrum" be used in patients manifesting this overlap to emphasize the importance of searching for the other malformations seen in this spectrum of anomalies.

Abnormalities, Multiple↗
PubMedDate not supplied

Confirmation of linkage of Van der Woude syndrome to chromosome 1q32: evidence of association with STR alleles suggests possible unique origin of the disease mutation.

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder with high penetrance and variable expression. Its clinical features are variably expressed, but include cleft lip and/or cleft palate, lip pits and hypodontia. All VWS families studied to date map the disease gene to a < 2 cM region of chromosome 1q32, with no evidence of locus heterogeneity. The aim of this study is to refine the localization of the VWS gene and to further assess possible heterogeneity. We analyzed four multiplex VWS families. All available members were clinically assessed and genotyped for 19 short tandem repeat markers on chromosome 1 in the VWS candidate gene region. We performed two-point and multipoint limit of detection (LOD) score analyses using a high penetrance autosomal dominant model. All families showed positive LOD scores without any recombination in the candidate region. The largest two-point LOD score was 5.87. Our assay method for short tandem repeat (STR) markers provided highly accurate size estimation of marker allele fragment sizes, and therefore enabled us to determine the specific alleles segregating with the VWS gene in each of our four families. We observed a striking pattern of STR allele sharing at several closely linked loci among our four Caucasian VWS families recruited at three different locations in the US. These results suggest the possibility of a unique origin for a mutation responsible for many or most cases of VWS.

Alleles↗