Histopathological alterations, EROD activity, CYP1A protein and biliary metabolites in gilthead seabream Sparus aurata exposed to benzo(a)pyrene

This study compared for seabream, Sparus aurata exposed to benzo(a)pyrene-B(a)P-, the response of molecular cytochrome P450 1A (CYP1A) and cellular histopathology biomarkers. Male gilthead seabream, Sparus aurata specimens were exposed for 20 days via water to a series of high B(a)P concentrations. CYP1A was assessed by measuring enzymatic activity (EROD) and CYP1A protein content, and cellular responses were evaluated by routine histopathological methods. In addition, biliary metabolites were measured in order to verify that B(a)P was absorbed and metabolised. Histological lesions, both in liver and gills, increased in parallel to B(a)P concentrations, with the majority of changes representing rather non-specific alterations. Hepatic EROD and CYP1A proteins data showed a concentration-dependent induction, while in the gills, EROD activity but not CYP1A proteins showed a non-monotonous dose response, with a maximum induction level at 200 microg B(a)P.L-1 and decreasing levels thereafter. The findings provide evidence that short-term, high dose exposure of fish can result in significant uptake and metabolism of the lipophilic B(a)P, and in pronounced pathological damage of absorptive epithelia and internal organs.

Effects of continuous remifentanil administration on intra-operative subcutaneous tissue oxygen tension

Surgical stress response markedly increases sympathetic nerve activity and catecholamine concentrations. This may contribute to peripheral vasoconstriction, reduced wound perfusion and subsequent tissue hypoxia. Opioids are known to depress the hypothalamic-adrenal response to surgery in a dose-dependent manner. We tested the hypothesis that continuous remifentanil administration produces improved subcutaneous tissue oxygen tension compared to fentanyl bolus administration. Forty-six patients undergoing major abdominal surgery were randomly assigned to receive either fentanyl bolus administration or continuous remifentanil infusion. Mean subcutaneous tissue oxygen values over the entire intra-operative period were significantly higher in the remifentanil group, when compared to the fentanyl group: 8 (2) kPa vs 6.7 (1.5) kPa, % CI difference: - 2.3 kPa to - 0.3 kPa, p = 0.013. Continuous intra-operative opioid administration may blunt vasoconstriction caused by surgical stress and adrenergic responses more than an equi-effective anaesthetic regimen based on smaller-dose bolus opioid administration.

Radiological anatomy of the obturator nerve and its articular branches: basis to develop a method of radiofrequency denervation for hip joint pain

OBJECTIVE: A previous study of radiofrequency neurotomy of the articular branches of the obturator nerve for hip joint pain produced modest results. Based on an anatomical and radiological study, we sought to define a potentially more effective radiofrequency method. DESIGN: Ten cadavers were studied, four of them bilaterally. The obturator nerve and its articular branches were marked by wires. Their radiological relationship to the bone structures on fluoroscopy was imaged and analyzed. A magnetic resonance imaging (MRI) study was undertaken on 20 patients to determine the structures that would be encountered by the radiofrequency electrode during different possible percutaneous approaches. RESULTS: The articular branches of the obturator nerve vary in location over a wide area. The previously described method of denervating the hip joint did not take this variation into account. Moreover, it approached the nerves perpendicularly. Because optimal coagulation requires electrodes to lie parallel to the nerves, a perpendicular approach probably produced only a minimal lesion. In addition, MRI demonstrated that a perpendicular approach is likely to puncture femoral vessels. Vessel puncture can be avoided if an oblique pass is used. Such an approach minimizes the angle between the target nerves and the electrode, and increases the likelihood of the nerve being captured by the lesion made. Multiple lesions need to be made in order to accommodate the variability in location of the articular nerves. CONCLUSIONS: The method that we described has the potential to produce complete and reliable nerve coagulation. Moreover, it minimizes the risk of penetrating the great vessels. The efficacy of this approach should be tested in clinical trials.

Mammary epithelial-specific knockout of the ephrin-B2 gene leads to precocious epithelial cell death at lactation

The family of Eph receptor tyrosine kinases and their membrane bound ligands, the ephrins, are involved in a wide variety of morphogenic processes during embryonic development and adult tissue homeostasis. Receptor-ligand interaction requires direct cell-cell contact and results in forward and reverse signaling originating from the receptor and ligand, respectively. We have previously shown that EphB4 and ephrinB2 are differentially expressed during the development of the adult mammary parenchyma. Overexpression of EphB4 in the mammary epithelium of transgenic mice leads to perturbations in mammary epithelial morphology, motility and growth. To investigate the role of ephrinB2 signaling in mammary gland biology, we have established transgenic mice exhibiting conditional ephrinB2 knockout in the mammary epithelium. In homozygote double transgenic CreLox mice, specific knockout of ephrinB2 occurred in the mammary epithelium during the first pregnancy-lactating period. Abolishing ephrinB2 function led to severe interference with the architecture and functioning of the mammary gland at lactation. The morphology of the transgenic lactating glands resembled that of involuting controls, with decreased epithelial cell number and collapsed lobulo-alveolar structures. Accordingly, massive epithelial cell death and expression of involution-specific genes were observed. Interestingly, in parallel to cell death, significant cell proliferation was apparent, suggestive of tissue regeneration.

A Closed-Form, Consistent and Robust Solution to Uncalibrated Photometric Stereo Via Local Diffuse Reflectance Maxima

Images of an object under different illumination are known to provide strong cues about the object surface. A mathematical formalization of how to recover the normal map of such a surface leads to the so-called uncalibrated photometric stereo problem. In the simplest instance, this problem can be reduced to the task of identifying only three parameters: the so-called generalized bas-relief (GBR) ambiguity. The challenge is to find additional general assumptions about the object, that identify these parameters uniquely. Current approaches are not consistent, i.e., they provide different solutions when run multiple times on the same data. To address this limitation, we propose exploiting local diffuse reflectance (LDR) maxima, i.e., points in the scene where the normal vector is parallel to the illumination direction (see Fig. 1). We demonstrate several noteworthy properties of these maxima: a closed-form solution, computational efficiency and GBR consistency. An LDR maximum yields a simple closed-form solution corresponding to a semi-circle in the GBR parameters space (see Fig. 2); because as few as two diffuse maxima in different images identify a unique solution, the identification of the GBR parameters can be achieved very efficiently; finally, the algorithm is consistent as it always returns the same solution given the same data. Our algorithm is also remarkably robust: It can obtain an accurate estimate of the GBR parameters even with extremely high levels of outliers in the detected maxima (up to 80 % of the observations). The method is validated on real data and achieves state-of-the-art results.

The importance of biotic interactions and local adaptation for plant response to environmental changes: field evidence along an elevational gradient

Predicting the response of species to environmental changes is a great and on-going challenge for ecologists, and this requires a more in-depth understanding of the importance of biotic interactions and the population structuration in the landscape. Using a reciprocal transplantation experiment, we tested the response of five species to an elevational gradient. This was combined to a neighbour removal treatment to test the importance of local adaptation and biotic interactions. The trait studied was performance measured as survival and biomass. Species response varied along the elevational gradient, but with no consistent pattern. Performance of species was influenced by environmental conditions occurring locally at each site, as well as by positive or negative effects of the surrounding vegetation. Indeed, we observed a shift from competition for biomass to facilitation for survival as a response to the increase in environmental stress occurring in the different sites. Unlike previous studies pointing out an increase of stress along the elevation gradient, our results supported a stress gradient related to water availability, which was not strictly parallel to the elevational gradient. For three of our species, we observed a greater biomass production for the population coming from the site where the species was dominant (central population) compared to population sampled at the limit of the distribution (marginal population). Nevertheless, we did not observe any pattern of local adaptation that could indicate adaptation of populations to a particular habitat. Altogether, our results highlighted the great ability of plant species to cope with environmental changes, with no local adaptation and great variability in response to local conditions. Our study confirms the importance of taking into account biotic interactions and population structure occurring at local scale in the prediction of communities’ responses to global environmental changes.

Identification of gunshots to the head by detection of RNA in backspatter primarily expressed in brain tissue

Traces of backspatter recovered from the inside of the barrel of a gun that was used to deliver suicidal or homicidal contact shots may be a source of valuable forensic evidence and first systematic investigations of the persistence of victim DNA from inside firearms have been presented. The aim of the present study was to include victim RNA in such analyses to determine the origin of tissues in addition and parallel to standard DNA profiling for forensic identification purposes. In a first step, suitable mRNA (C1orf61) and micro-RNAs (miR-124a and miR-124*) that are primarily expressed in brain tissue were selected from potential candidates and confirmed using quantitative PCR (qPCR). Secondly, a co-extraction procedure for RNA and DNA was established and brain differentiability of the selected RNAs was demonstrated via qPCR using samples from experimental shots at ballistic models. In a third step, this procedure was successfully applied to analyse samples from real casework comprising eight cases of suicidal contact shots. In this pilot study, we are first to report the possibility of co-extracting mRNA, miRNA and DNA from ballistic trace samples collected from the inside of firearms and we demonstrate that RNA and DNA based analyses can be performed in parallel to produce informative and highly complementary evidence.