Angular Distribution of Diffuse Reflectance in Biological Tissue

doi:10.1364/AO.46.006552We measured angular-resolved diffuse reflectance in tissue samples of different anisotropic characteristics. Experimental measurements were compared with theoretical results based on the diffusion approximation. The results indicated that the angular distribution in isotropic tissue was the same as in isotropic phantoms. Under normal incidence, the measured angular profiles of diffuse reflectance approached the Lambertian distribution when the evaluation location was far away from the incident point. The skewed angular profiles observed under oblique incidence could be explained using the diffuse model. The anisotropic tissue structures in muscle showed clear effects on the measurements especially at locations close to the light incidence. However, when measuring across the muscle fiber orientations, the results were in good agreement with those obtained in isotropic samples.This project was supported in part by National Science Foundation grant CBET-0643190, and the National Research Initiative of the USDA Cooperative State Research, Education, and Extension Service under grant 2006-35503-17619

Stink Bug Feeding Induces Fluorescence in Developing Cotton Bolls

<p>Abstract</p> <p>Background</p> <p>Stink bugs (Hemiptera: Pentatomidae) comprise a critically important insect pest complex affecting 12 major crops worldwide including cotton. In the US, stink bug damage to developing cotton bolls causes boll abscission, lint staining, reduced fiber quality, and reduced yields with estimated losses ranging from 10 to 60 million dollars annually. Unfortunately, scouting for stink bug damage in the field is laborious and excessively time consuming. To improve scouting accuracy and efficiency, we investigated fluorescence changes in cotton boll tissues as a result of stink bug feeding.</p> <p>Results</p> <p>Fluorescent imaging under long-wave ultraviolet light showed that stink bug-damaged lint, the inner carpal wall, and the outside of the boll emitted strong blue-green fluorescence in a circular region near the puncture wound, whereas undamaged tissue emissions occurred at different wavelengths; the much weaker emission of undamaged tissue was dominated by chlorophyll fluorescence. We further characterized the optimum emission and excitation spectra to distinguish between stink bug damaged bolls from undamaged bolls.</p> <p>Conclusions</p> <p>The observed characteristic fluorescence peaks associated with stink bug damage give rise to a fluorescence-based method to rapidly distinguish between undamaged and stink bug damaged cotton bolls. Based on the fluorescent fingerprint, we envision a fluorescence reflectance imaging or a fluorescence ratiometric device to assist pest management professionals with rapidly determining the extent of stink bug damage in a cotton field.</p

Monitoring Sarcomere Structure Changes in Whole Muscle Using Diffuse Light Reflectance

doi:10.1117/1.2234278Normal biomechanical and physiological functions of striated muscles are facilitated by the repeating sarcomere units. Light scattering technique has been used in studying single extracted muscle fibers. However, few studies, if any, have been conducted to investigate the possibility of using optical detection to examine sarcomere structure changes in whole muscles. We conducted a series of experiments to demonstrate that optical scattering properties measured in whole muscle are related to changes in sarcomere structure. These results suggest that photon migration technique has a potential for characterizing in vivo tissue ultrastructure changes in whole muscle

EFFECTS OF LOW CONCENTRATIONS OF ROTENONE UPON MITOHORMESIS IN SH-SY5Y CELLS

The mitochondrial toxin rotenone exerts cytotoxicity via overproduction of reactive oxygen species (ROS) and depolarization of the mitochondrial membrane. We investigated the effects of rotenone (12.5, 25, 50, 100 nmol/L) on mitochondrial biogenesis and the potential roles of ROS production in SH-SY5Y cells. Mitochondrial biogenesis was assessed by counting the number of mitochondria, determining protein expression of peroxisome proliferator-activated receptor γ coactivator α (PGC1-α) and its regulator, SIRT1, and oxygen consumption. ROS production and levels of reduced glutathione (GSH) and oxidized glutathione(GSSG) were also determined. Compared with controls, rotenone (12.5 nmol/L) significantly increased the quantity of mitochondria and amount of oxygen consumption, whereas rotenone at \u3e12.5 nmol/L decreased the quantity of mitochondria and amount of oxygen consumption. GSH contents and GSH/GSSG were also significantly enhanced by rotenone at 12.5 nmol/L and decreased by rotenone at \u3e12.5 nmol/L. Except for ROS production and SIRT1 protein expression, all concentration–response relationships showed a typical inverted-U shape. ROS production was continually increased in cells treated with rotenone. These data indicate that low concentrations of rotenone can induce mitohormesis, which may be attributed to ROS production

Down-regulated miR-9 and miR-433 in human gastric carcinoma

<p>Abstract</p> <p>Background</p> <p>MircoRNAs(miRNAs) are short, endogenously non-coding RNAs. The abnormal expression of miRNAs may be valuable for the diagnosis and treatment of tumors.</p> <p>Methods</p> <p>To screening the special miRNAs in gastric carcinoma, expression level of miRNAs in gastric carcinoma and normal gaster samples were detected by miRNA gene chip. Then, the expressions of miR-9 and miR-433 in gastric carcinoma tissue and SGC7901 cell line were validated by qRT-PCR. GRB2 and RAB34, targets of miR-433 and miR-9 respectively, were detected by Western blot.</p> <p>Results</p> <p>We found 19 miRNAs and 7 miRNAs were down-regulated and up-regulated respectively. Compared with normal gaster samples, our data showed that miR-9 and miR-433 were down-regulated in gastric carcinoma. Meanwhile, we also found that miR-433 and miR-9 regulated the expression levels of GRB2 and RAB34 respectively.</p> <p>Conclusion</p> <p>Our data show miR-9 and miR-433 was down-regulated in gastric carcinoma. The targets of miR-433 and miR-9 were tumor-associated proteins GRB2 and RAB34 respectively. This result provided the related information of miRNAs in gastric carcinoma.</p

Sono-photoacoustic imaging of gold nanoemulsions: Part I. Exposure thresholds

AbstractIntegrating high contrast bubbles from ultrasound imaging with plasmonic absorbers from photoacoustic imaging is investigated. Nanoemulsion beads coated with gold nanopsheres (NEB-GNS) are excited with simultaneous light (transient heat at the GNS's) and ultrasound (rarefactional pressure) resulting in a phase transition achievable under different scenarios, enhancing laser-induced acoustic signals and enabling specific detection of nanoprobes at lower concentration. An automated platform allowed dual parameter scans of both pressure and laser fluence while recording broadband acoustic signals. Two types of NEB-GNS and individual GNS were investigated and showed the great potential of this technique to enhance photoacoustic/acoustic signals. The NEB-GNS size distribution influences vaporization thresholds which can be reached at both permissible ultrasound and light exposures at deep penetration and at low concentrations of targets. This technique, called sono-photoacoustics, has great potential for targeted molecular imaging and therapy using compact nanoprobes with potentially high-penetrability into tissue

Memory Impairment Induced by Borna Disease Virus 1 Infection is Associated with Reduced H3K9 Acetylation

Background/Aims: Borna disease virus 1 (BoDV-1) infection induces cognitive impairment in rodents. Emerging evidence has demonstrated that Chromatin remodeling through histone acetylation can regulate cognitive function. In the present study, we investigated the epigenetic regulation of chromatin that underlies BoDV-1-induced cognitive changes in the hippocampus. Methods: Immunofluorescence assay was applied to detect BoDV-1 infection in hippocampal neurons and Sprague-Dawley rats models. The histone acetylation levels both in vivo and vitro were assessed by western blots. The acetylation-regulated genes were identified by ChIP-seq and verified by RT-qPCR. Cognitive functions were evaluated with Morris Water Maze test. In addition, Golgi staining, and electrophysiology were used to study changes in synaptic structure and function. Results: BoDV-1 infection of hippocampal neurons significantly decreased H3K9 histone acetylation level and inhibited transcription of several synaptic genes, including postsynaptic density 95 (PSD95) and brain-derived neurotrophic factor (BDNF). Furthermore, BoDV-1 infection of Sprague Dawley rats disrupted synaptic plasticity and caused spatial memory impairment. These rats also exhibited dysregulated hippocampal H3K9 acetylation and decreased PSD95 and BDNF protein expression. Treatment with the HDAC inhibitor, suberanilohydroxamic acid (SAHA), attenuated the negative effects of BoDV-1. Conclusion: Our results demonstrate that regulation of H3K9 histone acetylation may play an important role in BoDV-1-induced memory impairment, whereas SAHA may confer protection against BoDV-1-induced cognitive impairments. This study finds important mechanism of BoDV-1 infection disturbing neuronal synaptic plasticity and inducing cognitive dysfunction from the perspective of histone modification

Accelerating the Translation of Nanomaterials in Biomedicine

Due to their size and tailorable physicochemical properties, nanomaterials are an emerging class of structures utilized in biomedical applications. There are now many prominent examples of nanomaterials being used to improve human health, in areas ranging from imaging and diagnostics to therapeutics and regenerative medicine. An overview of these examples reveals several common areas of synergy and future challenges. This Nano Focus discusses the current status and future potential of promising nanomaterials and their translation from the laboratory to the clinic, by highlighting a handful of successful examples

Accelerating the Translation of Nanomaterials in Biomedicine

Due to their size and tailorable physicochemical properties, nanomaterials are an emerging class of structures utilized in biomedical applications. There are now many prominent examples of nanomaterials being used to improve human health, in areas ranging from imaging and diagnostics to therapeutics and regenerative medicine. An overview of these examples reveals several common areas of synergy and future challenges. This Nano Focus discusses the current status and future potential of promising nanomaterials and their translation from the laboratory to the clinic, by highlighting a handful of successful examples