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AbstractThe introduction of automation for immunoassays in recent years has brought about important and evident improvements in assay precision. Increasing standardization and comparability between platforms should enable the development of clinical guidelines and diagnostic algorithms for appropriate clinical decision making. A continuing source of variation between different automated immunoassay platforms is the sporadic effect of interfering antibodies or substances, thus causing aberrant results not supporting the patient's clinical status.The aim of this study was to describe current thyroid panel variation between automated immunoassay platforms including population specimens at risk of antibody interference. A multisite design with laboratories in three different countries using four different automated immunoassay platforms (Roche-Boehringer Mannheim Elecsys®(Italy), Roche-Boehringer Mannheim ES300®(Wales), Bayer Immuno 1®and the Bayer ACS:180®evaluated the thyroid panel of thyrotropin (TSH), triiodothyromine (T3), free thryroxine (FT4) and free triiodothyronine (FT3). A common set of 158 randomly selected patient samples of non-thyroid and thyroid disorders, with and without treatment, was tested. Included were 62 patient samples at risk for endogenous antibody interference with high antimicrosomal antibody, anti-TSH receptor antibody and increased rheumatoid factor sub-populations.Across all controls and between platforms, precision measurements were comparable and varied between 0.7% and 12.8% for TSH, 2.8% and 13% for FT4, 1.8% and 10.5% for FT3 and 3.1% and 16% for T3 assay. Acceptable correlation and reproducibility were found between the three Bayer Immuno 1 platforms at each country's site with all four thyroid panel assays demonstrating r-values of 0.989 to 1.000 and slopes of 0.915 to 1.078. Comparisons between the different platforms showed acceptable correlation for all thyroid panel assays. Specimens containing rheumatoid factor were associated with a significantly increased variation between systems for the FT4 and FT3 assays (p < 0.01). This effect did not appear to be selective for a given platform. For specimens with raised autoimmune antibodies and therefore at risk of assay antibody interference, no variation could be observed between the platforms.

Spatial analyses of the distribution of Ca2+in resting and activated T and B lymphocytes have shown that the bulk of increased [Ca2+]iappears to be associated with the nuclear region. These observations suggest that Ca2+is released from the perinuclear space or that it diffuses to the nucleoplasm, or both. We have used laser scanning confocal microscopy to assess whether cytoplasmic diffusion of Ca2+could contribute to the rise in nuclear Ca2+. We found that the activation of individual Jurkat cells by use of an anti‐Ti (β‐subunit) mAb induced a nucleus‐associated increase in [Ca2+]i. In cells loaded with the InsP3 receptor antagonist heparin, the nuclear Ca2+response was abolished but not the response to thapsigargin. Evidence for a cytoplasmic Ca2+response was obtained by loading Jurkat cells with a cytoplasm‐restricted Ca2+probe (Calcium Green‐1‐Dextran). These observations suggested that a process of diffusion of cytoplasmic Ca2+contributed to the rise of nuclear Ca2+in Jurkat T cells. This interpretation was supported by the findings (1) that rapid scanning of thapsigargin‐released Ca2+showed an inverse relationship between the levels of cytoplasmic and nuclear Ca2+and (2) that modulation of the external concentration of Ca2+in thapsigargin‐treated Jurkat cells showed a time‐dependent decrease of fluorescence from the nucleoplasm that was reversed by raising the concentration of external Ca2+. We conclude that Ca2+can rapidly diffuse between the cytoplasm and the nucleoplasm in activated Jurkat T lymphocytes and that hydrophilic Ca2+probes largely partition to the nucleoplasm, thus giving rise to distorted nucleus‐to‐cytoplasm fluorescence ratios. J. Leukoc. Biol. 62: 874–884; 1997.

We have used two disruptors of the cytoskeleton microtubular network (colchicine and vinblastine) to investigate the role of microtubules in Phaseolus vulgaris phytohemagglutinin (PHA) signal transduction in Jurkat T cells. Both drugs decreased but did not abolish the PHA-dependent Ca²⁺ response of Jurkat cells. Neither colchicine nor vinblastine had any major effects on the PHA-dependent turnover of the mono-, di-, tri-, and tetra-substituted phosphorylated derivatives of D-myo-inositol or the cellular distribution of protein kinase C (PKC) activity. However, both microtubule disruptors increased interleukin-2 (IL-2) production. Whereas vinblastine enhanced IL-2 production approximately twofold at all the concentrations tested (0.1, 1.0, and 10 µM), colchicine did so only at a 10 µM concentration. When a combination of PHA and 12-O-tetradecanoyl-13-O-acetyl phorbol (TPA) was used, a small increase in IL-2 production was observed only in the presence of vinblastine (10 µM). In contrast to recent reports that microfilaments may be involved in the regulation of signal transduction, our data suggest that this is not the case for microtubules in PHA-dependent signal transduction in Jurkat T cells. Copyright 1993, 1999 Academic Press

Abstract: Learning disabilities (LD) may cause academic failures among university students, but minor accommodations may in some instances allow students to progress satisfactorily. The current study validates a questionnaire for detecting students likely to have an LD. University students, 57 with a documented LD and 134 without, completed a Likert-scale questionnaire to assess the degree of self-perceived difficulty for 50 learning or testing situations. Wilcoxon rank sum test, separate logistic regression models, and determination of the best joint set of predictors of LD were carried out. The mean per-item questionnaire score was higher in the LD group (p < 0.0001); 47 individual items were significant predictors (i.e., p < 0.05) of LD status. The best joint set of predictors consisted of items dealing with word pronunciation, comprehending mathematical word problems, formulating summaries, spelling, slow reading rate, finishing tests in the allotted time, note-taking in lectures, and falling asleep while reading. Incorporating responses to these eight items, a formula was derived to determine the probability of LD. Taking 0.26 as the threshold for predicting the presence of an LD, the sensitivity of the questionnaire was 88%, the specificity was 87% for this population. The questionnaire could be an effective screening tool to detect university or professional students who should consider comprehensive testing for LD.

As a first approach to study the molecular mechanisms that underlie the effects of thyroid hormones on the developing brain, we used a cDNA microarray technology to identify early thyroid hormone-regulated genes in brain neuronal cultures treated with tri-iodothyronine (T3) for 3 h. We identified three genes that were up-regulated by T3, basic transcription element-binding protein, nuclear pore glycoprotein and bone morphogenetic protein-4 and one that was down-regulated, the neuronal apoptosis-inducing gene. We confirmed that these genes were also regulated by the thyroid state in the developing brain. Our findings enrich our knowledge of signaling pathways regulated by thyroid hormones and open new avenues for studying the molecular mechanisms of thyroid hormones in the developing brain.