Mise en évidence des prostaglandines PGE2 par immunofluorescence au sein de la paroi des kystes radiculo-dentaires

The present study gives the first evidence, through immunofluorescence, of the prostaglandins PGE2 in radicular cysts. The results are in agreement with literature. In addition, the immunofluorescence technique has also demonstrated the localization of prostaglandins inside the cyst cavity. In opposition to previous data, the present study also shows that epithelial cells seem to synthesize more PGE2 than fibroblasts and mononuclear components of the external connective tissue.Pour la première fois cette étude met en évidence par immunofluorescence les prostaglandines PGE2 dans les kystes radiculo-dentaires. La localisation de ces prostaglandines confirme les données de la littérature; de plus elle a permis leur mise en évidence dans la cavité kystique. Par ailleurs, contrairement aux travaux antérieurs, cette étude montre que les cellules épithéliales semblent synthétiser plus de PGE2 que les fibroblastes et les éléments mononucléés du tissu conjonctif de la couche externe

A new stylolite classification scheme to estimate compaction and local permeability variations

We modeled the geometrical roughening of bedding-parallel, mainly layer-dominated stylolites in order to understand their structural evolution, to present an advanced classification of stylolite shapes and to relate this classification to chemical compaction and permeability variations at stylolites. Stylolites are rough dissolution seams that develop in sedimentary basins during chemical compaction. In the Zechstein 2 carbonate units, an important lean gas reservoir in the southern Permian Zechstein basin in Germany, stylolites influence local fluid flow, mineral replacement reactions and hence the permeability of the reservoir. Our simulations demonstrate that layer-dominated stylolites can grow in three distinct stages: an initial slow nucleation phase, a fast layer-pinning phase and a final freezing phase if the layer is completely dissolved during growth. Dissolution of the pinning layer and thus destruction of the stylolite's compaction tracking capabilities is a function of the background noise in the rock and the dissolution rate of the layer itself. Low background noise needs a slower dissolving layer for pinning to be successful but produces flatter teeth than higher background noise. We present an advanced classification based on our simulations and separate stylolites into four classes: (1) rectangular layer type, (2) seismogram pinning type, (3) suture/sharp peak type and (4) simple wave-like type. Rectangular layer type stylolites are the most appropriate for chemical compaction estimates because they grow linearly and record most of the actual compaction (up to 40 mm in the Zechstein example). Seismogram pinning type stylolites also provide good tracking capabilities, with the largest teeth tracking most of the compaction. Suture/sharp peak type stylolites grow in a non-linear fashion and thus do not record most of the actual compaction. However, when a non-linear growth law is used, the compaction estimates are similar to those making use of the rectangular layer type stylolites. Simple wave-like stylolites are not useful for compaction estimates, since their growth is highly non-linear with a very low growth exponent. In the case where sealing material is collected at the tooth during dissolution, stylolites can act as barriers for local fluid flow as they intensify sealing capabilities of pinning layers. However, the development of teeth and spikes offsets and thus destroys continuous stylolite seams so that the permeability across the stylolite becomes very heterogeneous and they are no continuous barriers. This behavior is best shown in rectangular layer and seismogram pinning type stylolites that develop efficient fluid barriers at teeth tips but destroy sealing capabilities of layers by offsetting them at the flank, leading to a permeability anisotropy along 2-D stylolite planes. Suture/sharp peak stylolites can create fluid barriers if they collect enough sealing material. However, if the collecting material does not seal or if spikes offset the sealing material the stylolite leaks. We propose that our classification can be used to realistically estimate chemical compaction in reservoirs and gives an indication on how heterogeneous the permeability of stylolites can be

The Relevance of Grain Dissection for Grain Size Reduction in Polar Ice: Insights from Numerical Models and Ice Core Microstructure Analysis

The flow of ice depends on the properties of the aggregate of individual ice crystals, such as grain size or lattice orientation distributions. Therefore, an understanding of the processes controlling ice micro-dynamics is needed to ultimately develop a physically based macroscopic ice flow law. We investigated the relevance of the process of grain dissection as a grain-size-modifying process in natural ice. For that purpose, we performed numerical multi-process microstructure modelling and analysed microstructure and crystallographic orientation maps from natural deep ice-core samples from the North Greenland Eemian Ice Drilling (NEEM) project. Full crystallographic orientations measured by electron backscatter diffraction (EBSD) have been used together with c-axis orientations using an optical technique (Fabric Analyser). Grain dissection is a feature of strain-induced grain boundary migration. During grain dissection, grain boundaries bulge into a neighbouring grain in an area of high dislocation energy and merge with the opposite grain boundary. This splits the high dislocation-energy grain into two parts, effectively decreasing the local grain size. Currently, grain size reduction in ice is thought to be achieved by either the progressive transformation from dislocation walls into new high-angle grain boundaries, called subgrain rotation or polygonisation, or bulging nucleation that is assisted by subgrain rotation. Both our time-resolved numerical modelling and NEEM ice core samples show that grain dissection is a common mechanism during ice deformation and can provide an efficient process to reduce grain sizes and counter-act dynamic grain-growth in addition to polygonisation or bulging nucleation. Thus, our results show that solely strain-induced boundary migration, in absence of subgrain rotation, can reduce grain sizes in polar ice, in particular if strain energy gradients are high. We describe the microstructural characteristics that can be used to identify grain dissection in natural microstructures

Low-Iodine Diet of 4 Days Is Sufficient Preparation for I-131 Therapy in Differentiated Thyroid Cancer Patients

CONTEXT: No consensus exists about the optimal duration of the low-iodine diet (LID) in the preparation of (131)I therapy in differentiated thyroid cancer (DTC) patients. OBJECTIVE: This work aimed to investigate if a LID of 4 days is enough to achieve adequate iodine depletion in preparation for (131)I therapy. In addition, the nutritional status of the LID was evaluated. METHODS: In this prospective study, 65 DTC patients treated at 2 university medical centers were included between 2018 and 2021. The patients collected 24-hour urine on days 4 and 7 of the LID and kept a food diary before and during the LID. The primary outcome was the difference between the 24-hour urinary iodine excretion (UIE) on both days. RESULTS: The median 24-hour UIE on days 4 and 7 of the LID were not significantly different (36.1 mcg [interquartile range, 25.4-51.2 mcg] and 36.5 mcg [interquartile range, 23.9-47.7 mcg], respectively, P = .43). On day 4 of the LID, 72.1% of the DTC patients were adequately prepared (24-hour UIE < 50 mcg), and 82.0% of the DTC patients on day 7 (P = .18). Compared to the self-reported regular diet, DTC patients showed a significantly (P < .01) lower percentage of nutrient intake (calories, protein, calcium, iodine, and water) during the LID. CONCLUSION: The 24-hour UIE on day 4 of the LID did not differ from day 7, and therefore shortening the LID from 7 to 4 days seems justified to prepare DTC patients for (131)I therapy in areas with sufficient iodine intake and may be beneficial to maintain a sufficient nutritional intake during DTC treatment

All clinically-relevant blood components transmit prion disease following a single blood transfusion: a sheep model of vCJD

Variant CJD (vCJD) is an incurable, infectious human disease, likely arising from the consumption of BSE-contaminated meat products. Whilst the epidemic appears to be waning, there is much concern that vCJD infection may be perpetuated in humans by the transfusion of contaminated blood products. Since 2004, several cases of transfusion-associated vCJD transmission have been reported and linked to blood collected from pre-clinically affected donors. Using an animal model in which the disease manifested resembles that of humans affected with vCJD, we examined which blood components used in human medicine are likely to pose the greatest risk of transmitting vCJD via transfusion. We collected two full units of blood from BSE-infected donor animals during the pre-clinical phase of infection. Using methods employed by transfusion services we prepared red cell concentrates, plasma and platelets units (including leucoreduced equivalents). Following transfusion, we showed that all components contain sufficient levels of infectivity to cause disease following only a single transfusion and also that leucoreduction did not prevent disease transmission. These data suggest that all blood components are vectors for prion disease transmission, and highlight the importance of multiple control measures to minimise the risk of human to human transmission of vCJD by blood transfusion

Blood borne transit of CJD from brain to gut at early stages of infection

BACKGROUND: In Creutzfeldt-Jakob disease (CJD) and other related transmissible spongiform encephalopathies it is critical to understand the various pathways by which the infectious agent spreads to different organs. METHODS: We injected a CJD agent into mice, either intracerebrally (ic) or intraperitoneally (ip) and monitored the progressive appearance of abnormal PrP in peripheral tissues over time. RESULTS: Abnormal PrP was detected in lymphoreticular tissues of the gastrointestinal tract as early as 28 to 32 days after infection by both routes. This change persisted until the terminal stages of disease. In contrast, abnormal PrP was not detected in brain or spinal cord until 80 to 120 days after ic inoculation, or until 170 days after ip inoculation. CONCLUSIONS: Brain lacks significant lymphatic drainage, and has little infectivity before 40 days, even after ic inoculation. Thus the infectious inoculum must spread to the gut by a vascular route, a direction opposite to that generally assumed. This interpretation is consistent with previous studies demonstrating white blood cell infectivity as well as perivascular PrP accumulations in CJD. Notably, enteric infection at early as well as later stages of disease, and regardless of the route of agent entry, implicates potential environmental spread by fecal matter

Socially impaired robots: Human social disorders and robots’ socio-emotional intelligence

© Springer International Publishing Switzerland 2014. Social robots need intelligence in order to safely coexist and interact with humans. Robots without functional abilities in understanding others and unable to empathise might be a societal risk and they may lead to a society of socially impaired robots. In this work we provide a survey of three relevant human social disorders, namely autism, psychopathy and schizophrenia, as a means to gain a better understanding of social robots’ future capability requirements.We provide evidence supporting the idea that social robots will require a combination of emotional intelligence and social intelligence, namely socio-emotional intelligence. We argue that a robot with a simple socio-emotional process requires a simulation-driven model of intelligence. Finally, we provide some critical guidelines for designing future socio-emotional robots

Postsynaptic dysfunction is associated with spatial and object recognition memory loss in a natural model of Alzheimer's disease

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder associated with progressive memory loss, severe dementia, and hallmark neuropathological markers, such as deposition of amyloid-β (Aβ) peptides in senile plaques and accumulation of hyperphosphorylated tau proteins in neurofibrillary tangles. Recent evidence obtained from transgenic mouse models suggests that soluble, nonfibrillar Aβ oligomers may induce synaptic failure early in AD. Despite their undoubted value, these transgenic models rely on genetic manipulations that represent the inherited and familial, but not the most abundant, sporadic form of AD. A nontransgenic animal model that still develops hallmarks of AD would be an important step toward understanding how sporadic AD is initiated. Here we show that starting between 12 and 36 mo of age, the rodent Octodon degus naturally develops neuropathological signs of AD, such as accumulation of Aβ oligomers and phosphorylated tau proteins. Moreover, age-related changes in Aβ oligomers and tau phosphorylation levels are correlated with decreases in spatial and object recognition memory, postsynaptic function, and synaptic plasticity. These findings validate O. degus as a suitable natural model for studying how sporadic AD may be initiated

Comparative evidence for a link between Peyer's patch development and susceptibility to transmissible spongiform encephalopathies

BACKGROUND: Epidemiological analyses indicate that the age distribution of natural cases of transmissible spongiform encephalopathies (TSEs) reflect age-related risk of infection, however, the underlying mechanisms remain poorly understood. Using a comparative approach, we tested the hypothesis that, there is a significant correlation between risk of infection for scrapie, bovine spongiform encephalopathy (BSE) and variant CJD (vCJD), and the development of lymphoid tissue in the gut. METHODS: Using anatomical data and estimates of risk of infection in mathematical models (which included results from previously published studies) for sheep, cattle and humans, we calculated the Spearman's rank correlation coefficient, r(s), between available measures of Peyer's patch (PP) development and the estimated risk of infection for an individual of the corresponding age. RESULTS: There was a significant correlation between the measures of PP development and the estimated risk of TSE infection; the two age-related distributions peaked in the same age groups. This result was obtained for each of the three host species: for sheep, surface area of ileal PP tissue vs risk of infection, r(s )= 0.913 (n = 19, P < 0.001), and lymphoid follicle density vs risk of infection, r(s )= 0.933 (n = 19, P < 0.001); for cattle, weight of PP tissue vs risk of infection, r(s )= 0.693 (n = 94, P < 0.001); and for humans, number of PPs vs risk of infection, r(s )= 0.384 (n = 46, P = 0.008). In addition, when changes in exposure associated with BSE-contaminated meat were accounted for, the two age-related patterns for humans remained concordant: r(s )= 0.360 (n = 46, P = 0.014). CONCLUSION: Our findings suggest that, for sheep, cattle and humans alike there is an association between PP development (or a correlate of PP development) and susceptibility to natural TSE infection. This association may explain changes in susceptibility with host age, and differences in the age-susceptibility relationship between host species

Paracrine Diffusion of PrPC and Propagation of Prion Infectivity by Plasma Membrane-Derived Microvesicles

Cellular prion protein (PrPc) is a physiological constituent of eukaryotic cells. The cellular pathways underlying prions spread from the sites of prions infection/peripheral replication to the central nervous system are still not elucidated. Membrane-derived microvesicles (MVs) are submicron (0.1–1 µm) particles, that are released by cells during plasma membrane shedding processes. They are usually liberated from different cell types, mainly upon activation as well as apoptosis, in this case, one of their hallmarks is the exposure of phosphatidylserine in the outer leaflet of the membrane. MVs are also characterized by the presence of adhesion molecules, MHC I molecules, as well as of membrane antigens typical of their cell of origin. Evidence exists that MVs shedding provide vehicles to transfer molecules among cells, and that MVs are important modulators of cell-to-cell communication. In this study we therefore analyzed the potential role of membrane-derived MVs in the mechanism(s) of PrPC diffusion and prion infectivity transmission. We first identified PrPC in association with the lipid raft components Fyn, flotillin-2, GM1 and GM3 in MVs from plasma of healthy human donors. Similar findings were found in MVs from cell culture supernatants of murine neuronal cells. Furthermore we demonstrated that PrPSc is released from infected murine neuronal cells in association with plasma membrane-derived MVs and that PrPSc-bearing MVs are infectious both in vitro and in vivo. The data suggest that MVs may contribute both to the intercellular mechanism(s) of PrPC diffusion and signaling as well as to the process of prion spread and neuroinvasion