Cerebrospinal fluid and serum immunoglobulin G from 1007 patients with suspected neurological disease were analysed by 2 methods: isoelectric focusing for the detection of oligoclonal banding, and quantitative measurement of IgG and albumin for the formulation of a Log IgG-Index. A comparison of the 2 methods in the detection of local synthesis of IgG showed that isoelectric focusing not only gave a much higher yield overall, with 282 patients showing local synthesis versus 225 for the Log IgG-Index, but also a higher specificity, with a false positive rate of 0% versus 3.5%. In addition, of the 282 patients positive by isoelectric focusing only 163 (58%) were positive by the Log IgG-Index. Of the 1007 patients studied, 206 had multiple sclerosis (MS), and isoelectric focusing showed local synthesis in 95% of clinically definite cases, with a 90% detection rate overall. The Log IgG-Index was positive in only 67% of clinically definite cases, with an overall 59% detection rate. Thus with the exceptions noted above, local synthesis of IgG as defined by isoelectric focusing is confined to demyelinating, inflammatory, infectious and postinfectious disorders. Our results compare very favourably with the published sensitivities of magnetic resonance imaging in the detection of abnormalities in multiple sclerosis, and better than those for evoked potentials. Where both these investigations are readily available isoelectric focusing provides a useful adjunct. For the majority of physicians and neurologists who do not have ready access to magnetic resonance imaging, isoelectric focusing is an excellent alternative. We would also recommend that it become the standard for the measurement of IgG abnormalities in the cerebrospinal fluid and that the use of quantitative data be abandoned for routine purposes.

SUMMARY. A revised agarose isoelectric focusing method for detecting oligoclonal IgG in unconcentrated cerebrospinal fluid is presented. The technique is shown to be robust and reproducible and suitable for the detection of intrathecal IgG synthesis.

The present study assessed the effect of pig genotype (fatty v. lean) and dietary protein and lysine (Lys) levels (normal v. reduced) on intramuscular fat (IMF) content, subcutaneous adipose tissue (SAT) deposition, fatty acid composition and mRNA levels of genes controlling lipid metabolism. The experiment was conducted on sixty intact male pigs (thirty Alentejana purebred and thirty Large White £ Landrace £ Pietrain crossbred), from 60 to 93 kg of live weight. Animals were divided into three groups fed with the following diets: control diet equilibrated for Lys (17·5 % crude protein (CP) and 0·7 % Lys), reduced protein diet (RPD) equilibrated for Lys (13·2 % CP and 0·6 % Lys) and RPD not equilibrated for Lys (13·1 % CP and 0·4 % Lys). It was shown that the RPD increased fat deposition in the longissimus lumborum muscle in the lean but not in the fatty pig genotype. It is strongly suggested that the effect of RPD on the longissimus lumborum muscle of crossbred pigs is mediated via Lys restriction. The increase in IMF content under the RPD was accompanied by increased stearoyl-CoA desaturase (SCD) and PPARG mRNA levels. RPD did not alter backfat thickness, but increased the total fatty acid content in both lean and fatty pig genotype. The higher amount of SAT in fatty pigs, when compared with the lean ones, was associated with the higher expression levels of ACACA, CEBPA, FASN and SCD genes. Taken together, the data indicate that the mechanisms regulating fat deposition in pigs are genotype and tissue specific, and are associated with the expression regulation of the key lipogenic genes.

This paper describes the fabrication of a sensor for 1-hydroxypyrene (1-OHP) based on a screen-printed carbon electrode (SPCE) modified with a molecularly imprinted polymer (MIP); 1-OHP was chosen as a model metabolite of polyaromatic hydrocarbons (PAHs). It was shown that 1-OHP could be readily oxidised at a plain SPCE and the electrochemical mechanism was found to involve an ECE (electron transfer-chemical reaction-electron transfer) process. The MIP for 1-OHP was prepared using only divinylbenzene (DVB) and styrene as monomers and the binding was only based on hydrophobic interactions. Batch binding studies revealed that optimum uptake of 1-OHP by the MIP occurred from solutions containing 35% water in methanol. Selectivity of the binding sites in the MIP was examined by performing uptake studies in the same solution containing either phenol or 1-naphthol; the specific binding of 1-OHP was twenty times greater than the former and five times greater than the latter. Preliminary calibration studies were performed with the MIP-SPCE using a two-step approach; accumulation was carried out in 35% water in methanol followed by measurement in 50% methanol-0.025 mol dm(-3) phosphate buffer pH 12. This two-step non-competitive affinity assay gave encouraging results and indicated potential for use in pollution studies.

The cumulative effects of dietary arginine, leucine and protein levels on fat content, fatty acid composition and mRNA levels of genes controlling lipid metabolism in pig longissimus lumborum muscle and subcutaneous adipose tissue (SAT) were investigated. The experiment was performed on fifty-four intact male pigs (Duroc £ Pietrain £ Large White £ Landrace crossbred), with a live weight ranging from 59 to 92 kg. The pigs were randomly assigned to one of six experimental treatments (n 9). The treatments followed a 2 £ 3 factorial arrangement, with two levels of arginine supplementation (0 v. 1 %) and three levels of a basal diet (normal protein diet, NPD; reduced protein diet, RPD; reduced protein diet to achieve 2 % of leucine, RPDL). The results showed that dietary arginine supplementation did not affect the intramuscular fat (IMF) content and back fat thickness, but increased the total fat in SAT. This effect was associated with an increase in fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD) mRNA levels in SAT, which suggests that arginine might be involved in the differential regulation of some key lipogenic genes in pig muscle and SAT. The increase in IMF content under the RPD, with or without leucine supplementation, was accompanied by increased FASN and SCD mRNA levels. Arginine supplementation did not influence the percentage of main fatty acids, while the RPD had a significant effect on fatty acid composition in both tissues. Leucine supplementation of RPD did not change IMF, total fat of SAT and back fat thickness, but increased 16 : 0 and 18 : 1cis-9 and decreased 18 : 2n-6 in muscle.

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The paper presents a rapid immunoassay system capable of quantifying analyte in complex biological and environmental media. Antibody-coated micrometer-sized paramagnetic particles are used as labels in an assay in which they bind quantitatively with an analyte and capture antibody molecules immobilized on a polyester disk to form a sandwich assay. The assay is performed in a simple reaction vessel, and reactions between labels, analyte, and antibodies are accelerated by positioning magnets alternately above and below the vessel. The bound paramagnetic particles are quantified using a simple flat, spiral, coil located just below the polyester disk. The electronic circuitry associated with the coil uses components that are inexpensive and readily available. The coil has been designed to respond only to particles bound on the disk and not to unbound particles still in the test solution. Unbound particles are pulled away from the disk by the magnet before readings are taken. The use of the reaction vessel with the cardiac markers CRP and CKMB is described. No sample preparation or washing step is used in the assays, and results can be obtained in less than 3 min after introducing the sample into the vessel with sensitivities in the normal clinical range.