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61.
Ganglioneuromas of the thyroid gland of Sprague-Dawley rats were found in 7.2% of 698 rats used in two, 2-year oncogenicity bioassays. The incidence of the tumor was unrelated to treatment or sex. Of the 52 ganglioneuromas of the thyroid gland identified in 50 animals, 40 (80%) had coincident C cell proliferations in the same or contralateral lobe. Ganglioneuromas were contiguous or commingled with C cell proliferations in 63.5% of the cases. The ganglioneuromas consisted of large ganglion cells and, in a few cases, cells thought to be less differentiated neuronal precursors, in a matrix of neurites and Schwann cells. They grew, infiltrating and expanding in the thyroid parenchyma, and did not metastasize. Immunohistochemical staining for calcitonin, S-100 protein, and neurofilaments, as well as electron microscopy, were used to further characterize the tumors. The close association of ganglioneuromas with C cell tumors supports the theory of neural crest origin of C cells and provides a parallel to the association of ganglioneuromas and pheochromocytomas in the adrenal medulla. This is the first report of ganglioneuromas occurring in the thyroid gland or occurring as a common entity in any species.  相似文献   
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Climate change and anthropogenic disturbances may affect marine populations and ecosystems through multiple pathways. In this study we present a framework in which we integrate existing models and knowledge on basic regulatory processes to investigate the potential impact of future scenarios of fisheries exploitation and climate change on the temporal dynamics of the central Baltic herring stock. Alternative scenarios of increasing sea surface temperature and decreasing salinity of the Baltic Sea from a global climate model were combined with two alternative fishing scenarios, and their direct and ecosystem‐mediated effects (i.e., through predation by cod and competition with sprat) on the herring population were evaluated for the period 2010–2050. Gradual increase in temperature has a positive impact on the long‐term productivity of the herring stock, but it has the potential to enhance the recovery of the herring stock only in combination with sustainable fisheries management (i.e., Fmsy). Conversely, projections of herring spawning stock biomass (SSB) were generally low under elevated fishing mortality levels (Fhigh), comparable with those experienced by the stock during the 1990s. Under the combined effects of long‐term warming and high fishing mortality uncertainty in herring SSB projections was higher and increasing for the duration of the forecasts, suggesting a synergistic effect of fishery exploitation and climate forcing on fish populations dynamics. Our study shows that simulations of long‐term fish dynamics can be an informative tool to derive expectations of the potential long‐term impact of alternative future scenarios of exploitation and climate change.  相似文献   
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BACKGROUND: Previous work has demonstrated that piperonyl butoxide (PBO) not only inhibits microsomal oxidases but also resistance‐associated esterases. The ability to inhibit both major metabolic resistance enzymes makes it an ideal synergist to enhance xenobiotics but negates the ability to differentiate which enzyme group is responsible for conferring resistance. RESULTS: This study examines an analogue that retains the ability to inhibit esterases but is restricted in its ability to act on microsomal oxidases, thus allowing an informed decision on resistance enzymes to be made when used in conjunction with the parent molecule. CONCLUSION: Using examples of resistant insects with well‐characterised resistance mechanisms, a combination of PBO and analogue allows identification of the metabolic mechanism responsible for conferring resistance. The relative potency of PBO as both an esterase inhibitor and an oxidase inhibitor is also discussed. Copyright © 2008 Society of Chemical Industry  相似文献   
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This paper reports the results of a study conducted in Italy, within the AGFORWARD (2014–2017) project, aimed at promoting innovative agroforestry practices in Europe. Agroforestry offers a means for maintaining food production whilst addressing some of the negative environmental effects of intensive agriculture. This study aims to elicit the positive and negative points of view and perceptions of local stakeholders in Italy in relation to three types of agroforestry systems. The Participatory Research and Network Development was implemented in three workshops conducted in Sardinia, Umbria, and Veneto regions, and applied adopting a common methodological protocol. Qualitative data were obtained using open discussions with stakeholders on key issues, challenges and innovations. Quantitative data were obtained from stakeholders completing questionnaires during the workshops. A statistical analysis was applied to elicit the differences in stakeholders’ positive and negative perceptions in relation to production, management, environment and socio-economy aspects. Although the participants in the study came from different geographical and socioeconomic contexts with varied educational and cultural backgrounds, the different professional groups (farmers, policy-makers and researchers) and the three workshops generally shared similar perceptions of the benefits and constraints. The effects of agroforestry on production and the environment were generally perceived as positive, whilst those related to management were generally negative. The process of bringing the groups together seemed to be an effective means for identifying the key research gaps that need to be addressed in order to promote the uptake and maintenance of agroforestry.  相似文献   
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BACKGROUND: Piperonyl butoxide (PBO) effectively synergises synthetic pyrethroids, rendering even very resistant insect pests susceptible, provided a temporal element is included between exposure to synergist and insecticide. This concept is now applied to carbamates and neonicotinoids. RESULTS: A microencapsulated formulation of PBO and pirimicarb reduced the resistance factor in a clone of Myzus persicae (Sulzer) from >19 000- to 100-fold and in Aphis gossypii (Glover) from >48 000- to 30-fold. Similar results were obtained for a strain of Bemisia tabaci Gennadius resistant to imidacloprid and acetamiprid, although a second resistant strain did not exhibit such a dramatic reduction, presumably owing to the presence of target-site insensitivity and the absence of metabolic resistance. Synergism was also observed in laboratory susceptible insects, suggesting that, even when detoxification is not enhanced, there is degradation of insecticides by the background enzymes. Use of an analogue of PBO, which inhibits esterases but has reduced potency against microsomal oxidases, suggests that acetamiprid resistance in whiteflies is largely oxidase based. CONCLUSION: Temporal synergism can effectively enhance the activity of carbamates and neonicotinoids against resistant insect pests. Although the extent of this enhancement is dependent upon the resistance mechanisms present, inhibition of background enzymes can confer increased sensitivity against target-site resistance as well as increased metabolism. .  相似文献   
68.
Alpha1-acid glycoprotein (AGP) is an immunomodulatory protein expressed by hepatocytes in response to the systemic reaction that follows tissue damage caused by inflammation, infection or trauma. This paper presents the detection of bovine AGP (boAGP) in mammary secretions (colostrum and milk) and mammary gland tissue. Bovine AGP was detected by Western blotting in all the samples analysed, and could be quantified in colostrum at 162 (+/- 63.7) microg/mL and 114.5 (+/- 67.8) microg/mL during the first 12 h and 24 h respectively. In mature milk, the boAGP concentration clearly decreased and was no longer detectable using the Radial Immunodiffusion (RID) technique. The concentration of mature milk boAGP was therefore semi-quantified using an anion-exchange chromatographic procedure that allowed the concentration of the protein to be determined. The presence of AGP in bovine milk was confirmed by the internal sequence analysis performed following purification to homogeneity of the protein from milk. The concentration of AGP in bovine milk with low SCC (< 250,000) was very similar to that from bovine milk with high SCC (> 250,000). In order to investigate the origin of AGP in bovine milk, a search for mRNA was carried out in somatic cells and mammary gland tissue: mRNA expression of the boAGP gene was detected in mammary gland tissue, but not in somatic cells. Finally, the cDNA sequence of the boAGP was determined, and is hereby presented.  相似文献   
69.
Nitric oxide was found to trigger mitochondrial biogenesis in cells as diverse as brown adipocytes and 3T3-L1, U937, and HeLa cells. This effect of nitric oxide was dependent on guanosine 3',5'-monophosphate (cGMP) and was mediated by the induction of peroxisome proliferator-activated receptor gamma coactivator 1alpha, a master regulator of mitochondrial biogenesis. Moreover, the mitochondrial biogenesis induced by exposure to cold was markedly reduced in brown adipose tissue of endothelial nitric oxide synthase null-mutant (eNOS-/-) mice, which had a reduced metabolic rate and accelerated weight gain as compared to wild-type mice. Thus, a nitric oxide-cGMP-dependent pathway controls mitochondrial biogenesis and body energy balance.  相似文献   
70.
How climatic variability and anthropogenic pressures interact to influence recruitment is a key factor in achieving sustainable resource management. However, the combined effects of these pressures can make it difficult to detect non‐stationary interactions or shifts in the relationships with recruitment. Here we examine the links between climate and Irish Sea cod recruitment during a period of declining spawning stock biomass (SSB). Specifically, we test for a shift in the relationship between recruitment, SSB and climate by comparing an additive (generalized additive model, GAM) and non‐additive threshold model (TGAM). The relationship between recruitment success, SSB and the climatic driver, sea surface temperature, was best described by the TGAM, with a threshold identified between recruitment and SSB at approximately 7900 t. The analysis suggests a threshold shift in the relationship between recruitment and SSB in Irish Sea cod, with cod recruitment being more sensitive to climatic variability during the recent low SSB regime.  相似文献   
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