Field-based adipose tissue quantification in sea turtles using bioelectrical impedance spectroscopy validated with CT scans and deep learning.

Loss of adipose tissue in vertebrate wildlife species is indicative of decreased nutritional and health status and is linked to environmental stress and diseases. Body condition indices (BCI) are commonly used in ecological studies to estimate adipose tissue mass across wildlife populations. However, these indices have poor predictive power, which poses the need for quantitative methods for improved population assessments. Here, we calibrate bioelectrical impedance spectroscopy (BIS) as an alternative approach for assessing the nutritional status of vertebrate wildlife in ecological studies. BIS is a portable technology that can estimate body composition from measurements of body impedance and is widely used in humans. BIS is a predictive technique that requires calibration using a reference body composition method. Using sea turtles as model organisms, we propose a calibration protocol using computed tomography (CT) scans, with the prediction equation being: adipose tissue mass (kg) = body mass - (-0.03 [intercept] - 0.29 * length2/resistance at 50 kHz + 1.07 * body mass - 0.11 * time after capture). CT imaging allows for the quantification of body fat. However, processing the images manually is prohibitive due to the extensive time requirement. Using a form of artificial intelligence (AI), we trained a computer model to identify and quantify nonadipose tissue from the CT images, and adipose tissue was determined by the difference in body mass. This process enabled estimating adipose tissue mass from bioelectrical impedance measurements. The predictive performance of the model was built on 2/3 samples and tested against 1/3 samples. Prediction of adipose tissue percentage had greater accuracy when including impedance parameters (mean bias = 0.11%-0.61%) as predictor variables, compared with using body mass alone (mean bias = 6.35%). Our standardized BIS protocol improves on conventional body composition assessment methods (e.g., BCI) by quantifying adipose tissue mass. The protocol can be applied to other species for the validation of BIS and to provide robust information on the nutritional and health status of wildlife, which, in turn, can be used to inform conservation decisions at the management level.

Examination of trafficking of phagocytosed colloid particles in neutrophils using synchrotron-based X-ray fluorescence microscopy (XFM).

UNLABELLED: Synchrotron-based X-ray fluorescence microscopy (XFM) can localise chemical elements at a subcellular level. 99mTechnetium stannous (TcSn) colloid is taken up by phagocytes via a Complement Receptor 3 mediated phagocytic process. In the current study, XFM was used to examine the intracellular trafficking of TcSn colloid in neutrophils. XFM was performed on TcSn colloid, and neutrophils labelled with TcSn colloid, in whole blood. We developed a set of pixel by pixel analysis and mapping techniques incorporating cluster analysis that allowed us to differentiate neutrophils and artefactual contaminants, and we examined the changes in element distribution that accompany neutrophil phagocytosis of TcSn colloid. Sn became associated with half the neutrophils. Within cells, Sn colocalised with iron (Fe) and sulphur (S), and was negatively associated with calcium (Ca). Despite the high sensitivity of XFM, Tc was not detected. XFM can help clarify the intracellular processes that accompany neutrophil phagocytosis. The subcellular colocalisation of Sn with Fe is consistent with fusion of the colloid-containing phagosome with neutrophil granules. The association of Sn with S suggests that proteins rich in S-containing amino acids are present in the phagosome. The negative colocalisation with Ca indicates that ongoing maturation of the TcSn colloid phagosome is no longer calcium dependent one hour after phagocytosis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10867-011-9233-9) contains supplementary material, which is available to authorized users.

Clinically node-negative breast cancer, internal mammary lymph nodes, and sentinel lymph node biopsy.

We report 2 cases demonstrating that localization of internal mammary (IM) sentinel lymph nodes with lymphoscintigraphy using peritumoral injection of Tc-99m antimony sulfide colloid, followed by resection using minimal access surgery, can reveal nodal metastatic disease in patients with clinically node-negative breast cancer when axillary sentinel nodes are not affected by metastatic disease. When this is found, it changes staging and can affect prognosis and treatment. These cases confirm that the technique used is sampling true sentinel IM nodes, that is nodes that receive direct lymph flow from the breast cancer, and confirm the importance of sampling IM sentinel lymph nodes. Unless techniques are used that are specifically designed to identify IM node drainage from the breast cancer site itself, with subsequent directed surgical removal of sentinel IM nodes, some patients with breast cancer will not be staged correctly.

Neutrophil labeling with [(99m)Tc]-technetium stannous colloid is complement receptor 3-mediated and increases the neutrophil priming response to lipopolysaccharide.

INTRODUCTION: [(99m)Tc]-technetium stannous colloid (TcSnC)-labeled white cells are used to image inflammation. Neutrophil labeling with TcSnC is probably phagocytic, but the phagocytic receptor involved is not known. We hypothesised that complement receptor 3 (CR3) plays a key role. Phagocytic labeling could theoretically result in neutrophil activation or priming, affecting the behaviour of labeled cells. Fluorescence-activated cell sorter (FACS) analysis side scatter measurements can assess neutrophil activation and priming. METHODS: We tested whether TcSnC neutrophil labeling is CR3-mediated by assessing if neutrophil uptake of TcSnC was inhibited by a monoclonal antibody (mAb) directed at the CD11b component of CR3. We tested if TcSnC-labeled neutrophils show altered activation or priming status, comparing FACS side scatter in labeled and unlabeled neutrophils and examining the effect of lipopolysaccharide (LPS), a known priming agent. RESULTS: Anti-CD11b mAb reduced neutrophil uptake of TcSnC in a dose-dependent fashion. Labeled neutrophils did not show significantly increased side scatter compared to controls. LPS significantly increased side scatter in control cells and labeled neutrophils. However, the increase was significantly greater in labeled neutrophils than unlabeled cells. CONCLUSIONS: Neutrophil labeling with TcSnC is related to the function of CR3, a receptor which plays a central role in phagocytosis. TcSnC labeling did not significantly activate or prime neutrophils. However, labeled neutrophils showed a greater priming response to LPS. This could result in labeled neutrophils demonstrating increased adhesion on activated endothelium at sites of infection.