Microfluidic immunosensor systems

Immunosensing microfluidic devices are reviewed. Devices are commonly fabricated in glass, silicon, and polymers, with polymers seeing greater attention in recent years. Methods have been developed to immobilize antibodies and other molecules and resist non-specific adsorption through surface modification. The most common detection method is fluorescence, followed by electrochemistry. Various microfluidic designs have been reported for immunoassay applications. The observed trends in microfluidic immunoassay applications closely resemble the trends of general immunoassays, where large molecules are detected principally through a sandwich procedure, while competitive assays are used to detect smaller molecules. The following future trends are suggested: more sensitive detection, increased integration and miniaturization, multianalyte analysis, more robust reagents and devices, and increased functionality of surface treatments.     

Identification of MMP-15 as an anti-apoptotic factor in cancer cells

We have performed an in vitro selection for an anti-apoptotic phenotype that resembles the selection process that pre-malignant cells undergo in the initial phase of carcinogenesis in vivo. Using the cervical carcinoma cell line HeLa S3 as a model system, the selection procedure yielded cell clones that displayed increased resistance to apoptosis induced by Fas, tumor necrosis factor-related apoptosis-inducing ligand, and serum starvation. Gene expression profiling using gene family focused cDNA arrays revealed numerous genes that are differentially expressed in HeLa S3 and the resistant subclones and therefore are potentially involved in the definition of sensitivity to apoptotic stimuli. From the genes identified in this functional genomics approach we validated the anti-apoptotic activity of the membrane-anchored matrix metalloproteinase 15 (MMP-15) by means of small interfering RNA-mediated knock-down and ectopic expression in parental HeLa S3 cells and, to confirm a more general significance of our findings, in other cancer cell lines. The in vivo relevance of these findings is supported by the overexpression of MMP-15 in human lung adenocarcinoma compared with normal lung. Because MMP-15 is known to promote invasion, our results suggest that this protease connects metastasis and apoptosis resistance by an unknown regulatory mechanism. Our findings therefore strongly suggest that cancer characteristics such as metastatic potential, which are thought to evolve late in cancer progression, could be manifested early on by selection for an anti-apoptotic phenotype.     

Glucocorticoid receptor gene polymorphisms and disease activity during pregnancy and the postpartum period in rheumatoid arthritis

Introduction

The mechanism underlying the spontaneous improvement of rheumatoid arthritis (RA) during pregnancy and the subsequent postpartum flare is incompletely understood, and the disease course varies widely between pregnant RA patients. In pregnancy, total and free levels of cortisol increase gradually, followed by a postpartum decrease to prepregnancy values. The glucocorticoid receptor (GR) polymorphisms BclI and N363S are associated with relatively increased glucocorticoid (GC) sensitivity, whereas the 9β and ER22/23EK polymorphisms of the GR gene are associated with a relatively decreased GC sensitivity. We examined the relation between the presence of these GR polymorphisms and level of disease activity and disease course of RA during pregnancy and postpartum.

Methods

We studied 147 participants of the PARA study (Pregnancy-Induced Amelioration of Rheumatoid Arthritis study), a prospective study investigating the natural improvement during pregnancy and the postpartum flare in women with RA. Patients were visited, preferably before pregnancy, at each trimester and at three postpartum time points. On all occasions, disease activity was scored by using DAS28. All patients were genotyped for the GR polymorphisms BclI, N363S, 9β, and ER22/23EK and divided in groups harboring either polymorphisms conferring increased GC sensitivity (BclI and N363S; GC-S patients) or polymorphisms conferring decreased GC sensitivity (9β or 9β + ER22/23EK; GC-I patients). Data were analyzed by using a mixed linear model, comparing GC-S patients with GC-I patients with respect to improvement during pregnancy and the postpartum flare. The cumulative disease activity was calculated by using time-integrated values (area under the curve, AUC) of DAS28 in GC-I patients versus GC-S patients. Separate analyses were performed according to the state of GC use.

Results

GC-S patients treated with GC had a significantly lower AUC of DAS28 in the postpartum period than did GC-I patients. This difference was not observed in patients who were not treated with GCs. During pregnancy, GC-S and GC-I patients had comparable levels of disease activity and course of disease.

Conclusions

Differences in relative GC sensitivity, as determined by GR polymorphisms, are associated with the level of disease activity in the postpartum period in GC-treated patients, but they do not seem to influence the course of the disease per se.     

Destabilization of Long Astral Microtubules via Cdk1-Dependent Removal of GTSE1 from Their Plus Ends Facilitates Prometaphase Spindle Orientation

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A comparison of the effect of calcium and magnesium on the separate components of alkali cation uptake in excised barley roots

Summary In excised barley roots the presence of either Ca or Mg reduces the additional amount of Na taken up within the first few hours after immersion in a Na-solution, presumably by blocking the free penetration of Na through the outer cell barrier. In contrast, only Ca is effective in shifting the ratio in which Rb and Na are absorbed from a mixture of the two ions, the shift favouring Rb.Therefore, a direct although still unexplained action of Ca on the system involved in the absorption of monovalent cations, independent of effects resulting from its influence on cell permeability, is advocated.