Use of brightness wavelet transformation for automated analysis of serum metallothioneins- and zinc-containing proteins by Western blots to subclassify childhood solid tumours

Inhibitory effect of transferrin on serum zinc measurement

Bovine apo-transferrin (Tf) dose-dependently inhibited zinc (Zn) measurement if apo-Tf was added to a Zn standard solution followed by Zn measurement using a commercial Zn assay kit. Incubation of apo-Tf with zinc sulfate results in loss of Tf to inhibit Zn measurement, probably due to the binding of Tf with Zn. After treatment of Zn-binding Tf with ethylenediaminetetraacetic acid (EDTA) to generate apo-Tf, Zn measurement was even more strongly inhibited. However, when Zn standard solution was added to individual serum samples obtained from four dairy cows, the added Zn was almost recovered quantitatively. Apo-Tf had no effect on serum Zn measurement following its addition to serum samples. Apo-Tf and Zn standard solution was added to serum sample added Zn standard solution and apo-Tf, respectively, beforehand. The last added apo-Tf to the mixed solution showed higher Zn recovery (76-96%) as compared with the last added Zn standard solution (33-61%). Bovine serum albumin (BSA) did not affect the Zn recovery test, but apo-Tf inhibited Zn recovery even in the presence of BSA. These results suggested that, although Tf does not always inhibit serum Zn measurement, the Zn content of Zn-bound Tf could not be measured using the present Zn assay. Bovine serum contains Zn-binding protein with higher affinity to Zn than that of Apo-Tf. In addition, BSA does not inhibit the binding of apo-Tf with Zn, suggesting that BSA has lower affinity to Zn than that of apo-Tf.

Zinc and zinc-containing biomolecules in childhood brain tumors

Zinc ions are essential cofactors of a wide range of enzymes, transcription factors, and other regulatory proteins. Moreover, zinc is also involved in cellular signaling and enzymes inhibition. Zinc dysregulation, deficiency, over-supply, and imbalance in zinc ion transporters regulation are connected with various diseases including cancer. A zinc ion pool is maintained by two types of proteins: (i) zinc-binding proteins, which act as a buffer and intracellular donors of zinc and (ii) zinc transporters responsible for zinc fluxes into/from cells and organelles. The decreased serum zinc ion levels have been identified in patients suffering from various cancer diseases, including head and neck tumors and breast, prostate, liver, and lung cancer. On the contrary, increased zinc ion levels have been found in breast cancer and other malignant tissues. Zinc metalloproteomes of a majority of tumors including brain ones are still not yet fully understood. Current knowledge show that zinc ion levels and detection of certain zinc-containing proteins may be utilized for diagnostic and prognostic purposes. In addition, these proteins can also be promising therapeutic targets. The aim of the present work is an overview of the importance of zinc ions, zinc transporters, and zinc-containing proteins in brain tumors, which are, after leukemia, the second most common type of childhood cancer and the second leading cause of death in children after accidents.

3D printed chip for electrochemical detection of influenza virus labeled with CdS quantum dots

In this study, we report a new three-dimensional (3D), bead-based microfluidic chip developed for rapid, sensitive and specific detection of influenza hemagglutinin. The principle of microfluidic chip is based on implementation of two-step procedure that includes isolation based on paramagnetic beads and electrochemical detection. As a platform for isolation process, streptavidin-modified MPs, which were conjugated via biotinylated glycan (through streptavidin-biotin affinity) followed by linkage of hemagglutinin to glycan, were used. Vaccine hemagglutinin (HA vaxi) was labeled with CdS quantum dots (QDs) at first. Detection of the isolation product by voltammetry was the end point of the procedure. The suggested and developed method can be used also for detection of other specific substances that are important for control, diagnosis or therapy of infectious diseases.