Ultracompact fluorescence smartphone attachment using built-in optics for protoporphyrin-IX quantification in skin

Smartphone-based fluorescence imaging systems have the potential to provide convenient quantitative image guidance at the point of care. However, common approaches have required the addition of complex optical attachments, which reduce translation potential. In this study, a simple clip-on attachment appropriate for fluorescence imaging of protoporphyrin-IX (PpIX) in skin was designed using the built-in light source and ultrawide camera sensor of a smartphone. Software control for image acquisition and quantitative analysis was developed using the 10-bit video capability of the phone. Optical performance was characterized using PpIX in liquid tissue phantoms and endogenously produced PpIX in mice and human skin. The proposed system achieves a very compact form factor (<30 cm³) and can be readily fabricated using widely available low-cost materials. The limit of detection of PpIX in optical phantoms was <10 nM, with good signal linearity from 10 to 1000 nM (R² >0.99). Both murine and human skin imaging verified that in vivo PpIX fluorescence was detected within 1 hour of applying aminolevulinic acid (ALA) gel. This ultracompact handheld system for quantification of PpIX in skin is well-suited for dermatology clinical workflows. Due to its simplicity and form factor, the proposed system can be readily adapted for use with other smartphone devices and fluorescence imaging applications. Hardware design and software for the system is made freely available on GitHub (https://github.com/optmed/CompactFluorescenceCam).     

Survey of X-ray induced Cherenkov excited fluorophores with potential for human use

X-ray induced molecular luminescence (XML) is a phenomenon that can be utilized for clinical, deep-tissue functional imaging of tailored molecular probes. In this study, a survey of common or clinically approved fluorophores was carried out for their megavoltage X-ray induced excitation and emission characteristics. We find that direct scintillation effects and Cherenkov generation are two possible ways to cause these molecules’ excitation. To distinguish the contributions of each excitation mechanism, we exploited the dependency of Cherenkov radiation yield on X-ray energy. The probes were irradiated by constant dose of 6 MV and 18 MV X-ray radiation, and their relative emission intensities and spectra were quantified for each X-ray energy pair. From the ratios of XML, yield for 6 MV and 18 MV irradiation we found that the Cherenkov radiation dominated as an excitation mechanism, except for aluminum phthalocyanine, which exhibited substantial scintillation. The highest emission yields were detected from fluorescein, proflavin and aluminum phthalocyanine, in that order. XML yield was found to be affected by the emission quantum yield, overlap of the fluorescence excitation and Cherenkov emission spectra, scintillation yield. Considering all these factors and XML emission spectrum respective to tissue optical window, aluminum phthalocyanine offers the best XML yield for deep tissue use, while fluorescein and proflavine are most useful for subcutaneous or superficial use.     

表面粗糙度对牙科银汞合金抗折力的影响

目的比较不同表面粗糙度的牙科银汞合金试件的断裂载荷,探讨试件表面状况对脆性牙科材料抗折力的影响。方法制作直径10mm、厚2mm的圆盘形银汞试件48个．随机分成4组,其中3组分别以220、400、1200号SiC砂纸双面磨平．另一组不经打磨．表面保持试件制作完毕后的自然状态。每组随机抽取5个试件,置于粗糙度测试仪上测量表面粗糙度。试件于（23±1）。C空气中保存7d后置于30％玻璃纤维加强尼龙6．6基底上以20mm直径不锈钢球加载进行赫兹压痕试验,记录初始断裂载荷值并进行统计分析。结果未经打磨、220号、400号、1200号SiC砂纸打磨的试件的表面粗糙度平均值分别为1．77、1．99、1．28、0．66μm,断裂载荷值分别为（656．1±44．1）、（644．9±57．9）、（678.3±40．4）、（721．1±60．1）N。随着粗糙度的降低,初始断裂载荷值逐渐增加,1200号砂纸打磨组与未经打磨组和220号砂纸打磨组之间差异有统计学意义（P〈0．05）。结论脆性材料试件的表面粗糙度对其抗折能力有一定影响．     

Upregulation of micro RNA-146a (miRNA-146a), a marker for inflammatory neurodegeneration, in sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Straussler-Scheinker (GSS) syndrome

A mouse- and human-brain-abundant, nuclear factor (NF)-кB-regulated, micro RNA-146a (miRNA-146a) is an important modulator of the innate immune response and inflammatory signaling in specific immunological and brain cell types. Levels of miRNA-146a are induced in human brain cells challenged with at least five different species of single- or double-stranded DNA or RNA neurotrophic viruses, suggesting a broad role for miRNA-146a in the brain's innate immune response and antiviral immunity. Upregulated miRNA-146a is also observed in pro-inflammatory cytokine-, Aβ42 peptide- and neurotoxic metal-induced, oxidatively stressed human neuronal-glial primary cell cocultures, in murine scrapie and in Alzheimer's disease (AD) brain. In AD, miRNA-146a levels are found to progressively increase with disease severity and co-localize to brain regions enriched in inflammatory neuropathology. This study provides evidence of upregulation of miRNA-146a in extremely rare (incidence 1-10 per 100 million) human prion-based neurodegenerative disorders, including sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Straussler-Scheinker syndrome (GSS). The findings suggest that an upregulated miRNA-146a may be integral to innate immune or inflammatory brain cell responses in prion-mediated infections and to progressive and irreversible neurodegeneration of both the murine and human brain.     

Protoporphyrin IX fluorescence contrast in invasive glioblastomas is linearly correlated with Gd enhanced magnetic resonance image contrast but has higher diagnostic accuracy

The sensitivity and specificity of in vivo magnetic resonance (MR) imaging is compared with production of protoporphyrin IX (PpIX), determined ex vivo, in a diffusely infiltrating glioma. A human glioma transfected with green fluorescent protein, displaying diffuse, infiltrative growth, was implanted intracranially in athymic nude mice. Image contrast from corresponding regions of interest (ROIs) in in vivo MR and ex vivo fluorescence images was quantified. It was found that all tumor groups had statistically significant PpIX fluorescence contrast and that PpIX contrast demonstrated the best predictive power for tumor presence. Contrast from gadolinium enhanced T1-weighted (T1W+Gd) and absolute T2 images positively predicted the presence of a tumor, confirmed by the GFP positive (GFP+) and hematoxylin and eosin positive (H&E+) ROIs. However, only the absolute T2 images had predictive power from controls in ROIs that were GFP+ but H&E negative. Additionally, PpIX fluorescence and T1W+Gd image contrast were linearly correlated in both the GFP+ (r = 0.79, p<1×10(-8)) and H&E+ (r = 0.74, p<0.003) ROIs. The trace diffusion images did not have predictive power or significance from controls. This study indicates that gadolinium contrast enhanced MR images can predict the presence of diffuse tumors, but PpIX fluorescence is a better predictor regardless of tumor vascularity.     

Noninvasive fluorescence monitoring of protoporphyrin IX production and clinical outcomes in actinic keratoses following short-contact application of 5-aminolevulinate

Topical 5-aminolevulinic acid (ALA) is widely used in photodynamic therapy (PDT) of actinic keratoses (AK), a type of premalignant skin lesion. However, the optimal time between ALA application and exposure to light has not been carefully investigated. Our objective is to study the kinetics of protoporphyrin IX (PpIX) accumulation in AK after short contact ALA and relate this to erythemal responses. Using a noninvasive dosimeter, PpIX fluorescence measurements (5 replicates) were taken at 20-min intervals for 2 h following ALA application, in 63 AK in 20 patients. Data were analyzed for maximal fluorescent signal obtained, kinetic slope, and changes in erythema. Our results show that PpIX accumulation was linear over time, becoming statistically higher than background in 48% of all lesions by 20 min, 92% of lesions by 1 h, and 100% of lesions by 2 h. PpIX accumulation was roughly correlated with changes in lesional erythema post-PDT. We conclude that significant amounts of PpIX are produced in all AK lesions by 2 h. The linear kinetics of accumulation suggest that shorter ALA application times may be efficacious in many patients. Noninvasive fluorescence monitoring of PpIX may be useful to delineate areas of high PpIX accumulation within precancerous areas of the skin.     

Testing for heterogeneity among the components of a binary composite outcome in a clinical trial

Background  

Investigators designing clinical trials often use composite outcomes to overcome many statistical issues. Trialists want to maximize power to show a statistically significant treatment effect and avoid inflation of Type I error rate due to evaluation of multiple individual clinical outcomes. However, if the treatment effect is not similar among the components of this composite outcome, we are left not knowing how to interpret the treatment effect on the composite itself. Given significant heterogeneity among these components, a composite outcome may be judged as being invalid or un-interpretable for estimation of the treatment effect. This paper compares the power of different tests to detect heterogeneity of treatment effect across components of a composite binary outcome.