153 research outputs found
Variable role of carotid bodies in cardiovascular responses to exercise, hypoxia and hypercapnia in spontaneously hypertensive rats
The carotid body has recently emerged as a promising therapeutic target for treating cardiovascular disease, however the potential impact of carotid bodies removal on the dynamic cardiovascular responses to acute stressors such as exercise, hypoxia and hypercapnia in hypertension is an important safety consideration that has not been studied. We first validated a novel surgical approach to selectively resect the carotid bodies bilaterally (CBR) sparing the carotid sinus baroreflex. Second, we evaluated the impact of CBR on the cardiovascular responses to exercise, hypoxia and hypercapnia in the conscious, chronically instrumented spontaneously hypertensive (SH) rats. Our results confirm that our CBR technique successfully and selectively abolished the chemoreflex, whilst preserving carotid baroreflex function. CBR produced a sustained fall in arterial pressure in the SH rat of ~20 mmHg that persisted across both dark and light phases (P<0.001), with baroreflex function curves resetting around lower arterial pressure levels. The cardiovascular and respiratory responses to moderate forced exercise were similar between CBR and Sham. In contrast, CBR abolished the pressor response to hypoxia seen in Sham animals, although the increases in heart rate and respiration were similar between Sham and CBR groups. Both the pressor and respiratory responses to 7% hypercapnia were augmented after CBR (P<0.05) compared to sham. Our finding that the carotid bodies play a critical role in maintaining arterial pressure during hypoxia has important implications when considering resection therapy of the carotid body in disease states such as hypertension as well as heart failure with sleep apnoea
Towards a nanospecific approach for risk assessment.
In the current paper, a new strategy for risk assessment of nanomaterials is described, which builds upon
previous project outcomes and is developed within the FP7 NANoREG project. NANoREG has the aim to
develop, for the long term, new testing strategies adapted to a high number of nanomaterials where
many factors can affect their environmental and health impact. In the proposed risk assessment strategy,
approaches for (Quantitative) Structure Activity Relationships ((Q)SARs), grouping and read-across are
integrated and expanded to guide the user how to prioritise those nanomaterial applications that may
lead to high risks for human health. Furthermore, those aspects of exposure, kinetics and hazard
assessment that are most likely to be influenced by the nanospecific properties of the material under
assessment are identified. These aspects are summarised in six elements, which play a key role in the
strategy: exposure potential, dissolution, nanomaterial transformation, accumulation, genotoxicity and
immunotoxicity.
With the current approach it is possible to identify those situations where the use of nanospecific
grouping, read-across and (Q)SAR tools is likely to become feasible in the future, and to point towards the
generation of the type of data that is needed for scientific justification, which may lead to regulatory
acceptance of nanospecific applications of these tools.The research leading to these results has been partially funded
by the European Union Seventh Framework Programme (FP7/
2007e2013) under the project NANoREG (A common European
approach to the regulatory testing of nanomaterials), grant agreement
310584.info:eu-repo/semantics/publishedVersio
Efeito da temperatura do solo na infectividade e reprodução det Meloidogyne javanica e Heterodera glycines em cultivares de soja
Past and present land use influences on tropical riparian zones: an isotopic assessment with implications for riparian forest width determination
Antibiose e não preferência para oviposição de Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae) por cultivares de Vigna unguiculata (L.) Walp
Efeito da profundidade de semeadura na emergência de plântulas de tomate (Lycopersicon esculentum Mill.)
Desempenho de tambaqui cultivado em tanques-rede, em lago de várzea, sob diferentes taxas de alimentação
Effect of NPK fertilization on production and leaf nutrient content of eucalyptus minicuttings in nutrient solution
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