• Worm Sandberg opublikował 1 rok, 8 miesięcy temu

    As no post-marketing surveillance programs are required for supplements, our understanding of supplement risks is incomplete. Physicians should be wary of these risks and encourage further research and regulation.

    Accurate medical image interpretation is an essential proficiency for multiple medical specialties, including dermatologists and primary care providers. A dermatoscope, a ×10-×20 magnifying lens paired with a light source, enables enhanced visualization of skin cancer structures beyond standard visual inspection. Skilled interpretation of dermoscopic images improves diagnostic accuracy for skin cancer.

    Design and validation of Cutaneous Neoplasm Diagnostic Self-Efficacy Instrument (CNDSEI)-a new tool to assess dermatology residents’ confidence in dermoscopic diagnosis of skin tumors.

    In the 2018-2019 academic year, the authors administered the CNDSEI and the Long Dermoscopy Assessment (LDA), to measure dermoscopic image interpretation accuracy, to residents in 9 dermatology residency programs prior to dermoscopy educational intervention exposure. The authors conducted CNDSEI item analysis with inspection of response distribution histograms, assessed internal reliability using Cronbach’s coefficient alphgnment of medical image diagnostic performance and the self-efficacy instrument content offers opportunity for construct validation of novel medical image interpretation self-efficacy instruments.In the processes related to the development of cancer, there are different genetic and epigenetic events involved that result in structural changes of the affected cells. In the early stages of the disease, these changes occur at the nanoscale, remaining undetectable by conventional light microscopy, due to diffraction-limited resolution (∼250 – 550 nm). In this sense, a technique termed partial wave spectroscopy (PWS) allows the detection of these nanostructural changes by measuring a statistical parameter called disorder strength (L d ). PWS uses a combination of a tunable filter and a camera to acquire the backscattering spectra for each pixel on the image. In this paper, we study and validate the possibility of obtaining a qualitative measurement of the disorder using the spectrum of the averaged spatial information. Instead of using spatial information and measuring sequentially spectral ranges, we measure the backscattered signal gathered by an optical fiber by means of a spectrograph. This will allow this method to be applied in systems where it is not possible to acquire a complete high resolution image for many spectral bands, while significantly enhancing speed.We studied the elastic profile of monocytic THP-1 leukemia cells using a microfluidic-assisted optical trap. A 2-µm fused silica bead was optically trapped to mechanically dent an immobilized single THP-1 monocyte sieved on a 15-µm microfluidic capture chamber. Cells treated with Zeocin and untreated cells underwent RT-qPCR analysis to determine cell apoptosis through gene expression in relation to each cell’s deformation profile. Results showed that untreated cells with 43.05 ± 6.68 Pa are more elastic compared to the treated cells with 15.81 ± 2.94 Pa. THP-1 monocyte’s elastic modulus is indicative of cell apoptosis shown by upregulated genes after Zeocin treatment. This study clearly showed that the developed technique can be used to distinguish between cells undergoing apoptosis and cells not undergoing apoptosis and which may apply to the study of other cells and other cell states as well.Improving the imaging speed of multiphoton microscopy is an active research field. Among recent strategies, light-sheet illumination holds distinctive advantages for achieving fast imaging in vivo. However, photoperturbation in multiphoton light-sheet microscopy remains poorly investigated. We show here that the heart beat rate of zebrafish embryos is a sensitive probe of linear and nonlinear photoperturbations. By analyzing its behavior with respect to laser power, pulse frequency and wavelength, we derive guidelines to find the best balance between signal and photoperturbation. We then demonstrate one order-of-magnitude signal enhancement over previous implementations by optimizing the laser pulse frequency. These results open new opportunities for fast live tissue imaging.A retinal imaging system was designed for full-field (FF) swept-source (SS) optical coherence tomography (OCT) with cellular resolution. The system incorporates a real-time adaptive optics (AO) subsystem and a very high-speed CMOS sensor, and is capable of acquiring volumetric images of the retina at rates up to 1 kHz. While digital aberration correction (DAC) is an attractive potential alternative to AO, it has not yet been shown to provide resolution allowing visualization of cones in the fovea, where early detection of functional deficits is most critical. Here we demonstrate that FF-SS-OCT with hardware AO permits resolution of foveal cones, imaged at eccentricities of 1° and 2°, with volume rates adequate to measure light-evoked changes in photoreceptors. With the reference arm blocked, the system can operate as a kilohertz AO flood illumination fundus camera with adjustable temporal coherence and is expected to allow measurement of light-evoked changes caused by common path interference in photoreceptor outer segments (OS). In this paper, we describe the system’s optical design, characterize its performance, and demonstrate its ability to produce images of the human photoreceptor mosaic.Mueller matrix polarimetry (MMP) is a promising linear imaging modality that can enable visualization and measurement of the polarization properties of the cornea. Although the distribution of corneal birefringence has been reported, depth resolved MMP imaging of the cornea has not been archived and remains challenging. In this work, we perform depth-resolved imaging of the cornea using an improved system that combines Mueller matrix reflectance and transmission microscopy together with nonlinear microscopy utilizing second harmonic generation (SHG) and two photon excitation fluorescence (TPEF). We show that TPEF can reveal corneal epithelial cellular network while SHG can highlight the presence of corneal stromal lamellae. We then demonstrate that, in confocal reflectance measurement, as depth increases from 0 to 80 μm both corneal depolarization and retardation increase. Furthermore, it is shown that the spatial distribution of corneal depolarization and retardation displays similar complexity in both reflectance (confocal and non-confocal) and transmission measurement, likely due to the strong degree of heterogeneity in the stromal lamellae.During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury – i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) – a direct marker of cellular energy metabolism – and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (-0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.Because of the bulk, complexity, calibration requirements, and need for operator training, most current flow-based blood counting devices are not appropriate for field use. Standard imaging methods could be much more compact, inexpensive, and with minimal calibration requirements. However, due to the diffraction limit, imaging lacks the nanometer precision required to measure red blood cell volumes. To address this challenge, we utilize Mie scattering, which can measure nanometer-scale morphological information from cells, in a dark-field imaging geometry. The approach consists of a custom-built dark-field scattering microscope with symmetrically oblique illumination at a precisely defined angle to record wide-field images of diluted and sphered blood samples. Scattering intensities of each cell under three wavelengths are obtained by segmenting images via digital image processing. These scattering intensities are then used to determine size and hemoglobin information via Mie theory and machine learning. Validation on 90 clinical blood samples confirmed the ability to obtain mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW) with high accuracy. Simulations based on historical data suggest that an instrument with the accuracy achieved in this study could be used for widespread anemia screening.We present a wearable time-domain near infrared spectroscopy (TD-NIRS) system (two wavelengths, one detection channel), which fits in a backpack and performs real-time hemodynamic measurements on the brain and muscle tissues of freely moving subjects. It can provide concentration values of oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), total hemoglobin (tHb = O2Hb + HHb) and tissue oxygen saturation (StO2). The system is battery-operated and can be wirelessly controlled. By following established characterization protocols for performance assessment of diffuse optics instruments, we achieved results comparable with state-of-the-art research-grade TD-NIRS systems. We also performed in-vivo measurements such as finger tapping (motor cortex monitoring), breath holding (prefrontal cortex monitoring and forearm muscle monitoring), and outdoor bike riding (vastus lateralis muscle monitoring), in order to test the system capabilities in evaluating both muscle and brain hemodynamics.We demonstrate the highest resolution (1.5×1.5×1 µm) micrometer optical coherence tomography (µOCT) imaging of the morphologic micro-structure of excised swine and non-human primate corneas. Besides epithelial, stromal, and endothelial cell morphology, this report focuses on investigating the most peripheral corneal nerve fibers, the nerve fibers of the subbasal plexus (SBP). Alterations of SBP nerve density and composition are reportedly linked to major neurologic disorders, such as diabetic neuropathy, potentially indicating earliest onsets of denervation. Here, the fine, hyperreflective, epithelial nerve structures located just above Bowman’s membrane, are i) visualized using our µOCT prototype, ii) validated by comparison to fluorescence confocal microscopy (including selective immunohistochemical staining), and iii) segmented using state-of-the-art image processing. Here, we also introduce polarization sensitive (PS) µOCT imaging, demonstrating, to the best of our knowledge, the highest resolution corneal PS-OCT scans reported to date.

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