Abstract. The risk of local recurrence for breast cancers is strongly correlated with the presence of a tumor within 1 to 2 mm of the surgical margin on the excised specimen. Previous experimental and theoretical results suggest that spatially offset Raman spectroscopy (SORS) holds much promise for intraoperative margin analysis. Based on simulation predictions for signal-to-noise ratio differences among varying spatial offsets, a SORS probe with multiple source-detector offsets was designed and tested. It was then employed to acquire spectra from 35 frozen-thawed breast tissue samples in vitro. Spectra from each detector ring were averaged to create a composite spectrum with biochemical information covering the entire range from the tissue surface to ∼2 mm below the surface, and a probabilistic classification scheme was used to classify these composite spectra as "negative" or "positive" margins. This discrimination was performed with 95% sensitivity and 100% specificity, or with 100% positive predictive value and 94% negative predictive value. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).
Raman spectroscopy has enabled researchers to map the specific chemical makeup of surfaces, solutions, and even cells. However, the inherent insensitivity of the technique makes it difficult to use and statistically complicated. When Raman active molecules are near gold or silver nanoparticles, the Raman intensity is significantly amplified. This phenomenon is referred to as surface-enhanced Raman spectroscopy (SERS). The extent of SERS enhancement is due to a variety of factors such as nanoparticle size, shape, material, and configuration. The choice of Raman reporters and protective coatings will also influence SERS enhancement. This review provides an introduction to how these factors influence signal enhancement and how to optimize them during synthesis of SERS nanoparticles.
Cervical cancer is the second most common malignancy among women worldwide, with over 490000 cases diagnosed and 274000 deaths each year. Although current screening methods have dramatically reduced cervical cancer incidence and mortality in developed countries, a “See and Treat” method would be preferred, especially in developing countries. Results from our previous work have suggested that Raman spectroscopy can be used to detect cervical precancers; however, with a classification accuracy of 88%, it was not clinically applicable. In this paper, we describe how incorporating a woman's hormonal status, particularly the point in menstrual cycle and menopausal state, into our previously developed classification algorithm improves the accuracy of our method to 94%. The results of this paper bring Raman spectroscopy one step closer to being utilized in a clinical setting to diagnose cervical dysplasia. Posterior probabilities of class membership, as determined by MRDF-SMLR, for patients regardless of menopausal status, and for pre-menopausal patients only
The retinal pigment epithelium is an important part of the vertebrate eye, particularly in studying the causes and possible treatment of age-related macular degeneration. The retinal pigment epithelium is difficult to access in vivo due to its location at the back of the eye, making experimentation with age-related macular degeneration treatments problematic. An alternative to in vivo experimentation is cultivating the retinal pigment epithelium in vitro, a practice that has been going on since the 1970s, providing a wide range of retinal pigment epithelial culture protocols, each producing cells and tissue of varying degrees of similarity to natural retinal pigment epithelium. The purpose of this review is to provide researchers with a ready list of retinal pigment epithelial protocols, their effects on cultured tissue, and their specific possible applications. Protocols using human and animal retinal pigment epithelium cells, derived from tissue or cell lines, are discussed, and recommendations for future researchers included.
In traditional immuno-PCR a single antibody recognition event is associated with one to three DNA tags, which are subsequently amplified by PCR. Here, we describe a nanoparticle amplified immuno-PCR (NPA-IPCR) assay that combines antibody recognition of ELISA with a 50-fold nanoparticle valence amplification step prior to tag amplification by PCR. The assay detects a respiratory syncytial virus (RSV) surface protein using an antibody bound to a 15 nm gold nanoparticle co-functionalized with thiolated DNA complementary to a hybridized to 76-base tag DNA with a tag DNA to antibody ratio of 50 to 1. The presence of virus particles triggers the formation of a “sandwich” complex comprised of the gold nanoparticle construct, virus and an antibody functionalized magnetic particle used for extraction. After extraction, DNA tags are released by heating to 95°C and detected via real-time PCR. The limit of detection of the assay was compared to ELISA and RT-PCR using RSV infected HEp-2 cell extracts. NPA-IPCR showed a ~4000-fold improvement in the limit of detection compared to ELISA and a 4-fold improvement compared to viral RNA extraction followed by traditional RTPCR. NPA-IPCR offers a viable platform for the development of an early-stage diagnostics requiring an exceptionally low limit of detection.
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