SUMMARY Exosomes are secreted by all cell types and contain proteins and nucleic acids. Here, we report that breast cancer associated exosomes contain microRNAs (miRNAs) associated with the RISC Loading Complex (RLC) and display cell-independent capacity to process precursor microRNAs (pre-miRNAs) into mature miRNAs. Pre-miRNAs, along with Dicer, AGO2, and TRBP, are present in exosomes of cancer cells. CD43 mediates the accumulation of Dicer specifically in cancer exosomes. Cancer exosomes mediate an efficient and rapid silencing of mRNAs to reprogram the target cell transcriptome. Exosomes derived from cells and sera of patients with breast cancer instigate non-tumorigenic epithelial cells to form tumors in a Dicer-dependent manner. These findings offer opportunities for the development of exosomes based biomarkers and therapies.
This article reports the development of an optical imaging technique, confocal light absorption and scattering spectroscopic (CLASS) microscopy, capable of noninvasively determining the dimensions and other physical properties of single subcellular organelles. CLASS microscopy combines the principles of lightscattering spectroscopy (LSS) with confocal microscopy. LSS is an optical technique that relates the spectroscopic properties of light elastically scattered by small particles to their size, refractive index, and shape. The multispectral nature of LSS enables it to measure internal cell structures much smaller than the diffraction limit without damaging the cell or requiring exogenous markers, which could affect cell function. Scanning the confocal volume across the sample creates an image. CLASS microscopy approaches the accuracy of electron microscopy but is nondestructive and does not require the contrast agents common to optical microscopy. It provides unique capabilities to study functions of viable cells, which are beyond the capabilities of other techniques.light-scattering spectroscopy ͉ submicrometer ͉ native contrast ͉ imaging ͉ refractive index
Esophageal cancer is increasing in frequency in the United States faster than any other cancer. Barrett's esophagus, an otherwise benign complication of esophageal reflux, affects approximately three million Americans and precedes almost all cases of esophageal cancer. If detected as highgrade dysplasia (HGD), most esophageal cancers can be prevented. Standard-of-care screening for dysplasia uses visual endoscopy and a prescribed pattern of biopsy. This procedure, in which a tiny fraction of the affected tissue is selected for pathological examination, has a low probability of detection because dysplasia is highly focal and visually indistinguishable. We developed a system called endoscopic polarized scanning spectroscopy (EPSS), which performs rapid optical scanning and multispectral imaging of the entire esophageal surface and provides diagnoses in near real time. By detecting and mapping suspicious sites, guided biopsy of invisible, precancerous dysplasia becomes practicable. Here we report the development of EPSS and its application in several clinical cases, one of which merits special consideration.Previously we demonstrated that spectroscopic information in light scattered by nuclei could reveal precancer cellular changes 1 . The first application of light-scattering spectroscopy successfully detected dysplasia in Barrett's esophagus 1-5 using a fiber optic probe that illuminated 1 mm 2 of tissue. Searching the entire area of a diseased esophagus with a singlepoint probe is clinically impractical.Correspondence should be addressed to L.T.P. (ltperel@bidmc.harvard.edu). Note: Supplementary information is available on the Nature Medicine website. AUTHOR CONTRIBUTIONSL.Q., E.V., M.D.M., E.B.H., I.I. and L.T.P. developed and evaluated the method; S.I., L.Q. and E.V. contributed codes for instrument control; D.K.P., R.C., J.D.G., J.L., N.O., L.G., L.Q. and A.S. performed clinical procedures; L.Q., D.K.P., R.C., E.B.H., I.I. and L.T.P. contributed to the writing of the manuscript; E.B.H., I.I., D.K.P., R.C. and L.T.P. designed and planned the project. COMPETING FINANCIAL INTERESTSThe authors declare no competing financial interests.Reprints and permissions information is available online at http://npg.nature.com/reprintsandpermissions/. Since then, several new approaches have been explored using high-resolution endoscopy (HRE) combined with narrow band imaging (NBI) 6 , autofluorescence imaging (AFI) 7 , trimodal imaging 8 , which is a combination of the previous three, and confocal laser endomicroscopy 9 . These techniques showed promise in increased detection of dysplasia in Barrett's esophagus, although none has as yet achieved clinical acceptance. NIH Public AccessA clinically useful technique in the detection of dysplasia in Barrett's esophagus must rapidly survey a comparatively large area while simultaneously detecting changes on a cellular scale. We felt we could achieve both goals by combining an endoscopically compatible scanning instrument with polarized light-scattering spectroscopy (PLSS) 5...
The enormous increase of Raman signal in the vicinity of metal nanoparticles allows surface-enhanced Raman spectroscopy (SERS) to be employed for label-free detection of substances at extremely low concentrations. However, the ultimate potential of label-free SERS to identify pharmaceutical compounds at low concentrations, especially in relation to biofluid sensing, is far from being fully realized. Opioids are a particular challenge for rapid clinical identification because their molecular structural similarities prevent their differentiation with immunolabeling approaches. In this paper, we report a new method called quantitative label-free SERS (QLF-SERS) which involves the formation of halide-conjugated gold nanoclusters trapping the analyte of interest near the SERS hot spots, and we demonstrate that it yields a 105 fold improvement in the detection limit over previously reported results for the entire class of clinically-relevant opioids and their metabolites. Measurements of opioid concentrations in multi-component mixtures are also demonstrated. QLF-SERS has comparable detection limits as currently existing laboratory urine drug testing techniques but is significantly faster and inexpensive and, therefore, could be easily adapted as part of a rapid clinical laboratory routine.
From astronomy to cell biology, the manner in which light propagates in turbid media has been of central importance for many decades. However, light propagation near the point-of-entry (POE) in turbid media has never been analytically described, until now. Here we report a straightforward and accurate method that overcomes this longstanding, unsolved problem in radiative transport. Our theory properly treats anisotropic photon scattering events and takes the specific form of the phase function into account. As a result, our method correctly predicts the spatially dependent diffuse reflectance of light near the POE for any arbitrary phase function. We demonstrate that the theory is in excellent agreement with both experimental results and Monte Carlo simulations for several commonly used phase functions.
Red blood cell distribution width (RDW), platelet count (PLT), and a RDW-to-PLT ratio (RPR) have been associated with inflammatory activity and adverse outcomes in many diseases. This study has aimed to investigate the association between these indicators and the mortality rate of severe burn patients. From 2008 to 2014, 610 cases of severe burn patients from two burn centers in eastern China were enrolled in this study. Eighty-eight patients died within 90 days after admission. The RDW, PLT, and RPR were studied through Cox regression analysis on the 3rd and 7th day. The RDW, PLT, and RPR values on the 3rd and 7th day were significantly associated with the outcomes of severe burn patients (P < 0.01). High RPR was significantly associated with a 90-day mortality rate at the two time points. However, the RDW and PLT did not provide independent predictive values. Our results indicated that the RPR values on the 3rd and 7th day were associated with the mortality rates of severe burn patients (P < 0.01). Meanwhile, the RDW and PLT values at these time points failed to provide independent values for burn mortality prediction. Thus, the RPR can serve as an independent and novel marker for mortality rates prediction in severe burn patients.
We have developed a novel optical method for observing submicrometer intracellular structures in living cells, which is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light-scattering spectroscopy. CLASS microscopy requires no exogenous labels and is capable of imaging and continuously monitoring individual viable cells, enabling the observation of cell and organelle functioning at scales of the order of 100 nm.
Influence of alloy inhomogeneities on the determination by Raman scattering of composition and strain in Si1-xGex/Si(001) layers J. Appl. Phys. 112, 023512 (2012) Plasmon coupling in circular-hole dimers: From separation-to touching-coupling regimes J. Appl. Phys. 112, 013113 (2012) Correlation between reflectivity and resistivity in multi-component metallic systems Appl. Phys. Lett. 101, 011902 (2012) Ultrathin metallic coatings can induce quantum levitation between nanosurfaces
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