Multifractality in the Peripheral Cardiovascular System from Pointwise Hölder Exponents of Laser Doppler Flowmetry Signals

We study the dynamics of skin laser Doppler flowmetry signals giving a peripheral view of the cardiovascular system. The analysis of Hölder exponents reveals that the experimental signals are weakly multifractal for young healthy subjects at rest. We implement the same analysis on data generated by a standard theoretical model of the cardiovascular system based on nonlinear coupled oscillators with linear couplings and fluctuations. We show that the theoretical model, although it captures basic features of the dynamics, is not complex enough to reflect the multifractal irregularities of microvascular mechanisms.     

Quantitative IR microscopy and spectromics open the way to 3D digital pathology

Currently, only mass‐spectrometry (MS) microscopy brings a quantitative analysis of chemical contents of tissue samples in 3D. Here, the reconstruction of a 3D quantitative chemical images of a biological tissue by FTIR spectro‐microscopy is reported. An automated curve‐fitting method is developed to extract all intense absorption bands constituting IR spectra. This innovation benefits from three critical features: (1) the correction of raw IR spectra to make them quantitatively comparable; (2) the automated and iterative data treatment allowing to transfer the IR‐absorption spectrum into a IR‐band spectrum; (3) the reconstruction of an 3D IR‐band matrix (x, y, z for voxel position and a 4^th dimension with all IR‐band parameters). Spectromics, which is a new method for exploiting spectral data for tissue metadata reconstruction, is proposed to further translate the related chemical information in 3D, as biochemical and anatomical tissue parameters. An example is given with oxidative stress distribution and the reconstruction of blood vessels in tissues. The requirements of IR microscopy instrumentation to propose 3D digital histology as a clinical routine technology is briefly discussed.

     

Application of an angiosperm-based classification system (BiPo) to Mediterranean coastal waters: using spatial analysis and data on metal contamination of plants in identifying sources of pressure

The Biotic Index based on Posidonia oceanica (BiPo) is a classification system for evaluation of the ecological status in Mediterranean coastal waters, developed in accordance with the EU Water Framework requirements. The aim of this study is to verify the applicability and reliability of the BiPo index to different geographical areas of the north-western Mediterranean (France, Spain and Italy), to understand whether such a classification system may be applied more extensively, as so far it has only been applied to coastal waters in Corsica. The ecological status determined for sites is verified against pressures revealed from satellite imagery and from trace metal contamination of plants, to identify the sources of pressure that may be responsible for a low ecological status. The results of this study indicate that: (i) the BiPo index responds reliably to pressures, in different areas of the Mediterranean; (ii) sites with an ecological quality ratio (EQR) close to the good/moderate boundary require particular attention to identify and reduce causes of deterioration; (iii) the support of chemical indicators, in this case metal contamination, is relevant to identify potential sources of pressure.     

Density functional theory

Photosynthesis Research - Density functional theory (DFT) finds increasing use in applications related to biological systems. Advancements in methodology and implementations have reached a point...     

YAP and TAZ are essential for basal and squamous cell carcinoma initiation

YAP and TAZ are key downstream regulators of the Hippo pathway, regulating cell proliferation and differentiation. YAP and TAZ activation has been reported in different cancer types. However, it remains unclear whether they are required for the initiation of major skin malignancies like basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Here, we analyze the expression of YAP and TAZ in these skin cancers and evaluate cancer initiation in knockout mouse models. We show that YAP and TAZ are nuclear and highly expressed in different BCC types in both human and mice. Further, we find that cells with nuclear YAP and TAZ localize to the invasive front in well‐differentiated SCC, whereas nuclear YAP is homogeneously expressed in spindle cell carcinoma undergoing EMT. We also show that mouse BCC and SCC are enriched for YAP gene signatures. Finally, we find that the conditional deletion of YAP and TAZ in mouse models of BCC and SCC prevents tumor formation. Thus, YAP and TAZ are key determinants of skin cancer initiation, suggesting that targeting the YAP and TAZ signaling pathway might be beneficial for the treatment of skin cancers.     

Early vasodilator response to anodal current application in human is not impaired by cyclooxygenase-2 blockade

It is generally acknowledged that cutaneous vasodilatation in response to monopolar galvanic current application would result from an axon reflex in primary afferent fibers and the neurogenic inflammation resulting from neuropeptide release. Previous studies suggested participation of prostaglandin (PG) in anodal current-induced cutaneous vasodilatation. Thus the inducible cyclooxygenase (COX) isoform (COX-2), assumed to play a key role in inflammation, should be involved in the synthesis of the PG that is released. Skin blood flow (SkBF) variations induced by 5 min of 0.1-mA monopolar anodal current application were evaluated with laser-Doppler flowmetry on the forearm of healthy volunteers treated with indomethacin (COX-1 and COX-2 inhibitor), celecoxib (COX-2 inhibitor), or placebo. SkBF was indexed as cutaneous vascular conductance (CVC), expressed as percentage of heat-induced maximal CVC (%MVC). Urinalyses were performed to test celecoxib treatment efficiency. No difference was found in CVC values at rest: 14.3 +/- 4.0, 11.9 +/- 3.2, and 10.9 +/- 2.0% MVC after indomethacin, celecoxib, and placebo treatment, respectively. At 10 min after the onset of anodal current application, CVC values were 22.2 +/- 4.9% MVC (not significantly different from rest) with indomethacin, 85.7 +/- 15.3% MVC (P < 0.001 vs. rest) with celecoxib, and 70.4 +/- 13.1% MVC (P < 0.001 vs. rest) with placebo. Celecoxib significantly depressed the urinary prostacyclin metabolite 6-keto-PGF(1alpha) (P < 0.05 vs. placebo). Indomethacin, but not celecoxib, significantly inhibited the anodal current-induced vasodilatation. Thus, although they are assumed to result from an axon reflex in primary afferent fibers and neurogenic inflammation, these results suggest that the early anodal current-induced vasodilatation is mainly dependent on COX-1-induced PG synthesis.     

Mathematical modelling and phylodynamics for the study of dog rabies dynamics and control: A scoping review

BackgroundRabies is a fatal yet vaccine-preventable disease. In the last two decades, domestic dog populations have been shown to constitute the predominant reservoir of rabies in developing countries, causing 99% of human rabies cases. Despite substantial control efforts, dog rabies is still widely endemic and is spreading across previously rabies-free areas. Developing a detailed understanding of dog rabies dynamics and the impact of vaccination is essential to optimize existing control strategies and developing new ones. In this scoping review, we aimed at disentangling the respective contributions of mathematical models and phylodynamic approaches to advancing the understanding of rabies dynamics and control in domestic dog populations. We also addressed the methodological limitations of both approaches and the remaining issues related to studying rabies spread and how this could be applied to rabies control.Methodology/principal findingsWe reviewed how mathematical modelling of disease dynamics and phylodynamics have been developed and used to characterize dog rabies dynamics and control. Through a detailed search of the PubMed, Web of Science, and Scopus databases, we identified a total of n = 59 relevant studies using mathematical models (n = 30), phylodynamic inference (n = 22) and interdisciplinary approaches (n = 7). We found that despite often relying on scarce rabies epidemiological data, mathematical models investigated multiple aspects of rabies dynamics and control. These models confirmed the overwhelming efficacy of massive dog vaccination campaigns in all settings and unraveled the role of dog population structure and frequent introductions in dog rabies maintenance. Phylodynamic approaches successfully disentangled the evolutionary and environmental determinants of rabies dispersal and consistently reported support for the role of reintroduction events and human-mediated transportation over long distances in the maintenance of rabies in endemic areas. Potential biases in data collection still need to be properly accounted for in most of these analyses. Finally, interdisciplinary studies were determined to provide the most comprehensive assessments through hypothesis generation and testing. They also represent new avenues, especially concerning the reconstruction of local transmission chains or clusters through data integration.Conclusions/significanceDespite advances in rabies knowledge, substantial uncertainty remains regarding the mechanisms of local spread, the role of wildlife in dog rabies maintenance, and the impact of community behavior on the efficacy of control strategies including vaccination of dogs. Future integrative approaches that use phylodynamic analyses and mechanistic models within a single framework could take full advantage of not only viral sequences but also additional epidemiological information as well as dog ecology data to refine our understanding of rabies spread and control. This would represent a significant improvement on past studies and a promising opportunity for canine rabies research in the frame of the One Health concept that aims to achieve better public health outcomes through cross-sector collaboration.     

Extent of Mangrove Nursery Habitats Determines the Geographic Distribution of a Coral Reef Fish in a South-Pacific Archipelago

Understanding the drivers of species'' geographic distribution has fundamental implications for the management of biodiversity. For coral reef fishes, mangroves have long been recognized as important nursery habitats sustaining biodiversity in the Western Atlantic but there is still debate about their role in the Indo-Pacific. Here, we combined LA-ICP-MS otolith microchemistry, underwater visual censuses (UVC) and mangrove cartography to estimate the importance of mangroves for the Indo-Pacific coral reef fish Lutjanus fulviflamma in the archipelago of New Caledonia. Otolith elemental compositions allowed high discrimination of mangroves and reefs with 83.8% and 98.7% correct classification, respectively. Reefs were characterized by higher concentrations of Rb and Sr and mangroves by higher concentrations of Ba, Cr, Mn and Sn. All adult L. fulviflamma collected on reefs presented a mangrove signature during their juvenile stage with 85% inhabiting mangrove for their entire juvenile life (about 1 year). The analysis of 2942 UVC revealed that the species was absent from isolated islands of the New Caledonian archipelago where mangroves were absent. Furthermore, strong positive correlations existed between the abundance of L. fulviflamma and the area of mangrove (r = 0.84 for occurrence, 0.93 for density and 0.89 for biomass). These results indicate that mangrove forest is an obligatory juvenile habitat for L. fulviflamma in New Caledonia and emphasize the potential importance of mangroves for Indo-Pacific coral reef fishes.     

Mineral phase in shell repair of Manila clam Venerupis philippinarum affected by brown ring disease

The mineral phase of shell repair in the Manila clam Venerupis philippinarum affected by brown ring disease (BRD) was characterised at various scales and at various stages of shell repair by confocal Raman microspectrometry and scanning electron microscopy. Spherulitic and quadrangular aragonite microstructures associated with polyene pigments were clearly observed. Von Kossa staining showed that at the beginning of shell repair, hemocytes are filled with insoluble calcium carbonate salts in all fluids and then are transported toward the extrapallial fluids and the repair sites. Our analyses suggest that after a Vibrio tapetis attack and BRD deposit some clams rapidly cover the deposit, resulting in a modification in the microstructure, which could be produced by the participation of both the mantle and hemocytes.