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11.
Mesenchymal stem cells have been proposed to treat liver disease in the dog. The objective of this study was to compare portal, systemic intravenous and splenic injections for administration of mesenchymal stem cells to target the liver in healthy beagle dogs. Four healthy beagle dogs were included in the study. Each dog received mesenchymal stem cells via all three delivery methods in randomized order, 1 week apart. Ten million fat‐derived allogeneic mesenchymal stem cells labeled with Technetium‐99m (99mTc)‐hexamethyl‐propylene amine oxime(HMPAO) were used for each injection. Right lateral, left lateral, ventral, and dorsal scintigraphic images were obtained with a gamma camera equipped with a low‐energy all‐purpose collimator immediately after injection and 1, 6, and 24 h later. Mesenchymal stem cells distribution was assessed subjectively using all four views. Pulmonary, hepatic, and splenic uptake was quantified from the right lateral view, at each time point. Portal injection resulted in diffuse homogeneous high uptake through the liver, whereas the systemic intravenous injection led to mesenchymal stem cell trapping in the lungs. After splenic injection, mild splenic retention and high homogeneous diffuse hepatic uptake were observed. Systemic injection of mesenchymal stem cells may not be a desirable technique for liver therapy due to pulmonary trapping. Splenic injection represents a good alternative to portal injection. Scintigraphic tracking with 99mTc‐HMPAO is a valuable technique for assessing mesenchymal stem cells distribution and quantification shortly after administration. Data obtained at 24 h should be interpreted cautiously due to suboptimal labeling persistence.  相似文献   
12.
In developed countries, most of hepatitis E human cases are of zoonotic origin. Swine is a major hepatitis E virus (HEV) reservoir and foodborne transmissions after pork product consumption have been described. The risk for HEV-containing pig livers at slaughter time is related to the age at infection and to the virus shedding duration. Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a virus that impairs the immune response; it is highly prevalent in pig production areas and suspected to influence HEV infection dynamics. The impact of PRRSV on the features of HEV infections was studied through an experimental HEV/PRRSV co-infection of specific-pathogen-free (SPF) pigs. The follow-up of the co-infected animals showed that HEV shedding was delayed by a factor of 1.9 in co-infected pigs compared to HEV-only infected pigs and specific immune response was delayed by a factor of 1.6. HEV shedding was significantly increased with co-infection and dramatically extended (48.6 versus 9.7 days for HEV only). The long-term HEV shedding was significantly correlated with the delayed humoral response in co-infected pigs. Direct transmission rate was estimated to be 4.7 times higher in case of co-infection than in HEV only infected pigs (0.70 and 0.15 per day respectively). HEV infection susceptibility was increased by a factor of 3.3, showing the major impact of PRRSV infection on HEV dynamics. Finally, HEV/PRRSV co-infection – frequently observed in pig herds – may lead to chronic HEV infection which may dramatically increase the risk of pig livers containing HEV at slaughter time.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0207-y) contains supplementary material, which is available to authorized users.  相似文献   
13.
Seasonal variations in individual contacts give rise to a complex interplay between host demography and pathogen transmission. This is particularly true for wild populations, which highly depend on their natural habitat. These seasonal cycles induce variations in pathogen transmission. The seasonality of these biological processes should therefore be considered to better represent and predict pathogen spread. In this study, we sought to better understand how the seasonality of both the demography and social contacts of a mountain ungulate population impacts the spread of a pestivirus within, and the dynamics of, this population. We propose a mathematical model to represent this complex biological system. The pestivirus can be transmitted both horizontally through direct contact and vertically in utero. Vertical transmission leads to abortion or to the birth of persistently infected animals with a short life expectancy. Horizontal transmission involves a complex dynamics because of seasonal variations in contact among sexes and age classes. We performed a sensitivity analysis that identified transmission rates and disease-related mortality as key parameters. We then used data from a long-term demographic and epidemiological survey of the studied population to estimate these mostly unknown epidemiological parameters. Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns. We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics. Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0218-8) contains supplementary material, which is available to authorized users.  相似文献   
14.
Wild‐caught and pond‐reared female mud crab Scylla serrata at different stages of ovarian maturation were collected from Samar and Capiz, Philippines. Crabs were categorized into five stages according to the external morphological and microscopic appearance of the most advanced oocytes. The ovaries, hepatopancreas, muscle and newly spawned eggs (NSE) were analysed for lipid class components and fatty acids. Total lipid was higher in pond‐reared than in wild‐caught crabs but increased with ovarian maturation in both groups. Ovarian lipid peaked at the fully mature stage, coinciding with a decline in hepatopancreatic and muscle lipids. Lipid levels declined significantly in spent females. The tissues contained elevated highly unsaturated fatty acids such as arachidonic (20:4n‐6), eicosapentaenoic (20:5n‐3) and docosahexaenoic (22:6n‐3) acids, but at higher levels in late maturing and fully mature ovaries and in NSE. The type of lipid class and fatty acid components in mature ovaries as well as in NSE are generally considered to be indicative of their importance in reproductive physiology and embryonic and larval development.  相似文献   
15.
In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting. A method to extract and purify marennine has been developed, but its chemical structure could hitherto not be resolved. For decades, H. ostrearia was the only organism known to produce marennine, and can be found worldwide. Our knowledge about H. ostrearia-like diatom biodiversity has recently been extended with the discovery of several new species of blue diatoms, the recently described H. karadagensis, H. silbo sp. inedit. and H. provincialis sp. inedit. These blue diatoms produce different marennine-like pigments, which belong to the same chemical family and present similar biological activities. Aside from being a potential source of natural blue pigments, H. ostrearia-like diatoms thus present a commercial potential for aquaculture, cosmetics, food and health industries.  相似文献   
16.
This paper presents the results of physicochemical treatment on Pb-, Cu-, Sb-, and Zn-contaminated Canadian small arm firing range (SAFR) backstop soils in order to evaluate the potential of such methods for remediation of SAFR backstop soils. Remediation target for the treatment assays was to attain the Québec Department of Environment commercial C criterion or more realistically, to reach the soil burial D criterion. Two treatment lines (TL) were evaluated. TL-1, consisting of jig and Wilfley table (WT) treatments on the 0.5–3 mm and 53–500 μm soil size fractions (SF), respectively, and chemical leaching on the <53 μm SF and TL-2, consisting of jig on the 1–4 mm SF, spiral, and WT treatments on 250 μm–1 mm SF, and Kelsey jig assays on the <250 μm SF. For both TL, the untreated SF (>3 mm for TL-1; >4 mm for TL-2), and the gravimetric separation concentrates could be sent for recycling in smelter facilities. Results showed that the finer SF (<53 μm SF for TL-1; <250 μm SF for TL-2) were very difficult to treat. Even with metal removed mass proportions up to 78% for Pb, concentrations were still very high after chemical leaching; and the Kelsey jig showed deceiving metal removed mass proportions (up to 47% for Pb). In both TL, the jig and the WT showed Pb removed mass proportions up to 98% and treated mass proportions up to 77% in their respective SF. Whole process efficiencies in the cleaned soils showed that TL-1 led to the remediation of up to 65% of the initial total soil, and TL-2, 36%. TL-1 and TL-2 results showed that the WT effectively treated soils of 53 μm–1 mm SF, and the jig, soils of the 1–4 mm SF. Our study shows that gravimetric concentration techniques are very promising for the treatment of SAFR backstop soils, and further research has to be done in order to treat the SF lower than 53 μm.  相似文献   
17.
The relationship between chemical structure and gut microbial degradation rates of 14 flavonoids, flavone, apigenin, chrysin, naringenin, kaempferol, genistein, daidzein, daidzin, puerarin, 7,4'-dihydroxyflavone, 6,4'-dihydroxyflavone, 5,4'-dihydroxyflavone, 5,3'-dihydroxyflavone, and 4'-hydroxyflavone, was investigated by anaerobically fermenting the flavonoids with human gut microflora (n = 11 subjects). Degradation rates for the 5,7,4'-trihydroxyl flavonoids, apigenin, genistein, naringenin, and kaempferol, were significantly faster than the other structural motifs. Puerarin was resistant to degradation by the gut microflora. Extensive degradation of flavonoids by gut microflora may result in lower overall bioavailability than those flavonoids that are slowly degraded because rapidly degrading flavonoids are less likely to be absorbed intact.  相似文献   
18.
Recent studies in population dynamics suggest that landscape processes and habitat quality act at different scales on population abundances, but very few have modelled their simultaneous effects. However, at a time of large declines in natural populations, it is essential to understand such multivariate components. We tested the hypothesis that natural populations of palmate newts (Triturus helveticus) are affected on three scales: breeding patch (pond), habitat complementation (terrestrial cover), and metapopulation structure (density of ponds, surrounding populations). We conducted our survey in 130 ponds from southern France (Larzac) and analysed data with generalized additive models (GAM). Two main novel results emerge from these models: (1) the three landscape scales have significant effects on newt abundance, with more newts in deep, vegetated ponds, devoid of fish and surrounded by wooded areas and inhabited ponds; (2) the quality of the surrounding breeding patches is of primary importance in determining the abundance at core sites in a complex way: high abundances are associated positively with high densities of inhabited ponds, but negatively with the number of surrounding ponds. Deforestation, invasive species and abandonment of ponds all have negative impacts on the persistence of palmate newt populations. Future studies should encompass landscapes at different scales and incorporate the habitat quality in surrounding sites to better understand population dynamics and provide adequate conservation measures.  相似文献   
19.

Purpose

Suspended particulate matter (SPM) plays an important role in the transport and fate of contaminants in the environment. To better understand the relationships between contaminants and SPM, SPM properties, and their variations with flow regime, river size, land use, and season should be considered.

Materials and methods

The grain size distribution, elemental composition, and mineralogy of SPM from different stations along the Moselle River (Lorraine, France) were investigated at the particle scale during different flow regimes. The resulting data were compared with the elemental composition of the dissolved compartment to understand the role of particles in element transport.

Results and discussion

The grain size distribution, elemental composition, and mineralogy of SPM along the Moselle River and during different flow regimes showed only slight variations, except for the Fensch and Orne tributaries, two rivers that were impacted by inherited steel-making industrialization and different land use. In the Moselle River, SPM mainly consisted of clay minerals, while in Fensch and Orne Rivers, SPM mainly consisted of multiple types of anthropogenic particles. The diffuse urbanization gradient was hardly recognized based on the Trace Metal Element (TMEs) content in the river SPM, while the rivers impacted by the steel industries had greater TME contents. Finally, the TME content in the Moselle SPM was more strongly influenced by water flow than by the position of sampling on the linear reach of the Moselle River. The partitioning of TMEs in the particles and water at the main Moselle station (Frouard) revealed that SPM predominantly contributed to TMEs transport.

Conclusions

This study confirmed that catchment geology greatly contributed to the SPM composition in the mean-sized rivers. In addition, the high anthropogenic pressure could be deciphered for small tributaries. Furthermore, this study allowed us to observe the high contribution of particles to TMEs and Rare Earth Element (REEs) transportation.
  相似文献   
20.
Accepting as founded the hypothesis of a multifactorial origin for the Alzheimer's disease (AD), we explore the possible links between the geographical distribution of AD cases according to their birth place and the geochemical profile of the Saguenay-Lac-Saint-Jean (SLSJ) territory in the province of Québec. The method used for factor analysis of correspondances (FAC) and another one based on the differences between the residential and municipal geochemical concentrations (DRMC) have been used for this purpose. The geochemical matrix of SLSJ relates the highest concentrations of nickel, copper and zinc to the sector surrounding the Jonquière municipality. Moreover, high concentrations of iron, lead and manganese were found in the northern sector of the Lac Saint-Jean. The DRMC method corroborates this strong correlation between iron, lead and manganese. Furthermore, these concentrations do not differ from the north-american geochemical standards. No single geochemical element seems to be associate with the spatial distribution of cases. It is, however, still possible that a certain synergistic effect between two or several elements could be implied in the development of the disease. According to the results of the soil analysis, there does not seem to be any association between the spatial distribution of cases and the concentration of aluminum, a chemical element that has been thought to be implied in the etiology of AD. These results are compared with those obtained by other workers in the micronesian islands, where abnormally high frequencies of amyotrophic lateral sclerosis and parkinsonism dementia have already been observed.  相似文献   
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