Search

The Pigmented Lesion Assay (PLA, sensitivity 91-95%, specificity 69-91%, negative predictive value ?99%) is a commercially available, non-invasive gene expression test that helps dermatologists guide pigmented lesion management decisions and rule out melanoma. Earlier studies have demonstrated high clinical utility and no missed melanomas in a 3-6-month follow-up period. We undertook the current investigations to provide 12-month follow-up data on PLA(-) tests, and to further confirm utility. A 12-month chart review follow-up of 734 pigmented lesions that had negative PLA results from 5 US dermatology centers was performed. Thirteen of these lesions (1.8%) were biopsied in the follow-up period and submitted for histopathologic review. None of the lesions biopsied had a histopathologic diagnosis of melanoma. The test's utility was studied further in a registry (N=1575, 40 US dermatology offices, 62 participating providers), which demonstrated that 99.9% of PLA(-) lesions were clinically monitored, thereby avoiding a surgical procedure, and 96.5% of all PLA(+) lesions were appropriately biopsied, most commonly with a tangential shave. This long-term follow-up study confirms the PLA's high negative predictive value and high utility in helping guide the management of pigmented lesions to avoid unnecessary surgical procedures.

The revised version of the article corrected Figure 2. This change appears in the revised online PDF copy of this article.

Reversible addition--fragmentation chain transfer polymerization is employed here to 'allow detector-free visualization of specific DNA sequences for which dynamic polymer growth is used in signal amplification. In particular, surface-initiated polymer growth was regulated by the immobilization of chain transfer agents on the Au surface where DNA hybridization occurred. A linear polymer growth was observed as a function of the reaction time, characteristic of 'living' polymer reactions. Significant improvement in assay sensitivity was realized in comparison to the previously reported polymerization-based sensing method by enhancing polymer growth rate and reducing background noises caused by nonspecific adsorption. Direct visualization of fewer than 2,000 copies of a short oligonucleotide sequence was demonstrated in a detector-free fashion.

We report here a new DNA detection method in which polymer growth in atom transfer radical polymerization (ATRP) is used as a means to amplify detection signals. In this method, DNA hybridization and ligation reactions led to the attachment of ATRP initiators on a solid surface where specific DNA sequences were located. These initiators subsequently triggered the growth of poly(hydroxyethyl methacrylate) (PHEMA) at the end of immobilized DNA molecules and formed polymer brushes. The formation of PHEMA altered substrate opacity, rendering the corresponding spots readily distinguishable to the naked eye. A second ATRP reaction to form branched polymers on the surface drastically improved the visibility of DNA hybridization and significantly shortened the detection time. The resulting polymer film was characterized using infrared spectroscopy, ellipsometry, contact angle measurements, and atomic force microscopy. Direct visualization of 1 fmol of target DNA molecules of interest was demonstrated. A proof-of-principle experiment to detect DNA point mutation was conducted. The perfectly matched DNA targets were distinctively differentiated from those with mutations. The demonstrated capability to detect DNA mutation with direct visualization laid the groundwork for the future development of detector-free testing kits in single-nucleotide polymorphism screenings.

A consistent set of data were obtained using a combination of electrochemical NMR and computational methods to support the fact that backfolded linkages result in dendrimers that are more encapsulating yet smaller than their extended counter parts. The conclusion was made by direct comparison of sets of dendimers that differed only in the relative structural element.

The surface of poly(ethylene terephthalate) (PET) films crystallizes when exposed to a broad class of organic solvents (protic polar, aprotic polar, and non‐polar). This phenomenon leads to irreversible changes in transparency and mechanical properties. It also limits PET films and coatings in applications including electronics, medicine, packaging, and construction. This work describes a method to impart solvent resistance to the PET surface by depositing a silicate film. This coating enables many post‐functionalization options, including those that tune wettability or impart antifouling characteristics to the parent PET surface. It also endows PET surface resistance to organic solvent exposure without affecting the overall mechanical and optical properties of the PET. Additionally, the silicate layer improves the scratch resistance of PET surfaces. [ABSTRACT FROM AUTHOR]

A comparison of the heterogeneous electron-transfer rate constants of both flexible and rigid series of redox-active, iron-sulfur core dendrimers is presented. The flexible series were less effective at attenuating the rate of electron transfer than the rigid series.