Cancer is the cause of death for one in seven individuals worldwide. It is widely acknowledged that screening and early diagnosis are of vital importance for improving the likelihood of recovery. However, given the costly, time-consuming, and invasive nature of the many methods currently in use, patients often do not take advantage of the services available to them. Consequently, many researchers are exploring the possibility of developing fast, reliable, and non-invasive diagnostic tools that can be used directly or by local physicians at the point-of-care. Herein, we look at the use of established biomarkers in cancer therapy and investigate emerging biomarkers exhibiting future potential. The incorporation of these biomarkers into point-of-care devices could potentially reduce the strain currently experienced by screening programs in hospitals and healthcare systems. Results derived from point-of-care tests should be accurate, sensitive, and generated rapidly to assist in the selection of the best course of treatment for optimal patient care. Essentially, point-of-care diagnostics should enhance the well-being of patients and lead to a reduction in cancer-related deaths.
Harmful algal blooms in freshwater systems are increasingly common and present threats to drinking water systems, recreational waters, and ecosystems. A highly innovative simple to use, portable biosensor system (MBio) for the rapid and simultaneous detection of multiple cyanobacterial toxins in freshwater is demonstrated. The system utilizes a novel planar waveguide optical sensor that delivers quantitative fluorescent competitive immunoassay results in a disposable cartridge. Data are presented for the world's first duplex microcystin (MC)/cylindrospermopsin (CYN) assay cartridge using a combination of fluorophore-conjugated monoclonal antibodies as detector molecules. The on-cartridge detection limits of 20% inhibitory concentration (IC) was 0.4 μg/L for MC and 0.7 μg/L for CYN. MC assay coverage of eight important MC congeners was demonstrated. Validation using 45 natural lake water samples from Colorado and Lake Erie showed quantitative correlation with commercially available laboratory-based enzyme linked immunosorbent assays. A novel cell lysis module was demonstrated using cyanobacteria cultures. Results show equivalent or better performance than the gold-standard but more tedious 3× freeze-thaw method, with >90% cell lysis for laboratory cultures. The MBio system holds promise as a versatile tool for multiplexed field-based cyanotoxin detection, with future analyte expansion including saxitoxin, anatoxin-a, and marine biotoxins.
From an S49 mouse lymphoma cell subline that carries an electrophoretic marker mutation in one allele for a regulatory (R) subunit of cyclic AMP-dependent protein kinase, 130 cyclic AMP-resistant mutants were isolated and characterized. Of the 77 independent spontaneous and mutagen-induced isolates identified, 74 had kinases with increased apparent activation constants (KaS) for cyclic AMP-dependent activation. The "Ka" phenotype was invariably correlated with an apparent structural lesion in one R subunit allele. "Charge-shift" lesions in 43 independent isolates were mapped to small regions within the R subunit by two-dimensional gel analysis of partial proteolysis peptides. Nine Ka mutations were distinguished by differences in charge or peptide maps of mutant R subunits, and the mutations were clustered in two regions associated with the cyclic AMP-binding sites of the R subunit. The relative frequencies of different mutations differed among spontaneous, ethyl methanesulfonate-induced, and N-methyl-N'-nitro-N-nitrosoguanidine-induced isolates. Mutation frequencies were also markedly different for the two R subunit alleles; this allele preference was strongest for mutagen-induced lesions in the more carboxy terminal cyclic AMP-binding site.
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