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101.
Kristina S. Sobotka Stuart B. Hooper Kelly J. Crossley Tracey Ong Georg M. Schm?lzer Samantha K. Barton Annie R. A. McDougall Suzie L. Miller Mary Tolcos Claus Klingenberg Graeme R. Polglase 《PloS one》2016,11(1)
BackgroundA sustained inflation (SI) rapidly restores cardiac function in asphyxic, bradycardic newborns but its effects on cerebral haemodynamics and brain injury are unknown. We determined the effect of different SI strategies on carotid blood flow (CaBF) and cerebral vascular integrity in asphyxiated near-term lambs.MethodsLambs were instrumented and delivered at 139 ± 2 d gestation and asphyxia was induced by delaying ventilation onset. Lambs were randomised to receive 5 consecutive 3 s SI (multiple SI; n = 6), a single 30 s SI (single SI; n = 6) or conventional ventilation (no SI; n = 6). Ventilation continued for 30 min in all lambs while CaBF and respiratory function parameters were recorded. Brains were assessed for gross histopathology and vascular leakage.ResultsCaBF increased more rapidly and to a greater extent during a single SI (p = 0.01), which then decreased below both other groups by 10 min, due to a higher cerebral oxygen delivery (p = 0.01). Blood brain barrier disruption was increased in single SI lambs as indicated by increased numbers of blood vessel profiles with plasma protein extravasation (p = 0.001) in the cerebral cortex. There were no differences in CaBF or cerebral oxygen delivery between the multiple SI and no SI lambs.ConclusionsVentilation with an initial single 30 s SI improves circulatory recovery, but is associated with greater disruption of blood brain barrier function, which may exacerbate brain injury suffered by asphyxiated newborns. This injury may occur as a direct result of the initial SI or to the higher tidal volumes delivered during subsequent ventilation. 相似文献
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Joseph Merz Lucius Caldwell Michael Beakes Chris Hammersmark Kirsten Sellheim 《Restoration Ecology》2019,27(3):661-671
Gravel augmentation is often applied to rivers and streams to rehabilitate salmonid spawning and incubation habitat. However, the effect of gravel size on salmon spawning utilization and embryo survival during incubation is not well understood. We conducted an experiment on a regulated and previously mined Northern California salmonid‐bearing stream in which different sized gravel (small, medium, and large) patches were placed into the stream's degraded spawning reach. We documented Oncorhynchus tshawytscha (Chinook salmon) spawning activity within the three gravel sizes for two seasons. In addition, we deployed Chinook salmon embryos into each gravel size patch and allowed them to incubate until estimated emergence time. Although all experimental gravel sizes were predicted to be within the spawning population's mobilization capabilities, model results indicated the probability of salmon building redds decreased as substrate size increased. Conversely, embryo survival increased as gravel size increased. A possible mechanism of disparate Chinook salmon embryo survival is provided by an observed decrease in embryo survival correlating with greater presence of embryo predators (leeches), which are associated with smaller gravel. Our results indicate a parent‐offspring conflict in optimal spawning gravel size for Chinook salmon, and suggest that an intermediate gravel size would maximize overall reproductive success across both spawning and incubation life stages. 相似文献
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Nigel R. Franks James W. Hooper Mike Gumn Tamsyn H. Bridger James A. R. Marshall Roderich Groß Anna Dornhaus 《Swarm Intelligence》2007,1(2):81-94
Many decisions involve a trade-off between commitment and flexibility. We show here that the collective decisions ants make
over new nest sites are sometimes sufficiently flexible that the ants can change targets even after an emigration has begun.
Our findings suggest that, in this context, the ants’ procedures are such that they can sometimes avoid ‘negative information
cascades’ which might lock them into a poor choice. The ants are more responsive to belated good news of a higher quality
nest than they are when the nest they had initially chosen degraded to become worse than an alternative. Our study confirms,
in a new way, that ant colonies can be very powerful “search engines”. 相似文献
107.
Olsson F Denham M Cole TJ Hooper SB Mollard R 《Current stem cell research & therapy》2007,2(3):197-208
The reported pluripotential capabilities of many human stem cell types has made them an attractive area of research, given the belief they may hold considerable therapeutic potential for treating a wide range of human diseases and injuries. Although the bulk of stem cell based research has focused on developing procedures for the treatment of pancreatic, neural, cardiovascular and haematopoietic diseases, the potential for deriving respiratory cell types from stem cells for treatment of respiratory specific diseases has also been explored. It is suggested that stem cell derivatives may be used for lung replacement/regeneration therapeutics and high though-put pharmacological screening strategies for a variety of respiratory injuries and diseases including: cystic fibrosis, chronic obstructive pulmonary disease, respiratory distress syndrome, pulmonary fibrosis and pulmonary edema. This review will explore recent progress in characterizing adult respiratory and bone marrow derived stem cells with respiratory potential as well as the endogenous mechanisms directing the homing of these cells to the diseased and injured lung. In addition, the potential for embryonic stem cell based therapies in this domain as well as the histological, anatomical and molecular aspects of respiratory development will be summarized. 相似文献
108.
Michael Ulyshen Katherine Elliott Joel Scott Scott Horn Patsy Clinton Ning Liu Chelcy F. Miniat Peter Caldwell Chris Oishi Jennifer Knoepp Paul Bolstad 《Ecology and evolution》2022,12(3)
Rhododendron maximum is an evergreen shrub native to the Appalachian Mountains of North America that has expanded in recent decades due to past disturbances and land management. The purpose of this study was to explore how bees and plants were affected by the experimental removal of R. maximum followed by a prescribed fire in one watershed compared to a neighboring reference watershed. Bees and plants were sampled for three years in both watersheds. Comparisons were based on the rarefaction and extrapolation sampling curves of Hill numbers as well as multivariate methods to assess effects on community composition. Bee richness, Shannon''s diversity, and Simpson''s diversity did not differ between watersheds in the year after removal but were all significantly higher in the removal watershed in year two, following the prescribed fire. Bee Shannon''s diversity and Simpson''s diversity, but not richness, remained significantly higher in the removal watershed in the third year. Similar but weaker patterns were observed for plants. Comparisons of community composition found significant differences for bees in the second and third year and significant differences for plants in all three years. For both groups, significant indicator taxa were mostly associated with the removal watershed. Because bees appeared to respond more strongly to the prescribed fire than to the removal of R. maximum and these benefits weakened considerably one year after the fire, clearing R. maximum does not appear to dramatically improve pollinator habitat in the southern Appalachians. This conclusion is underscored by the fact that about one quarter of the bee species in our study area were observed visiting R. maximum flowers. The creation of open areas with wildflowers may be a better way to benefit bees in this region judging from the high diversity of bees captured in the small roadside clearings in this study. 相似文献
109.
Tom Z. Yuan Pankaj Garg Linya Wang Jordan R. Willis Eric Kwan Ana G Lujan Hernandez Emily Tuscano Emily N. Sever Erica Keane Cinque Soto Eric M. Mucker Mallorie E. Fouch Edgar Davidson Benjamin J. Doranz Shweta Kailasan M. Javad Aman Haoyang Li Jay W. Hooper Erica Ollmann Saphire James E. Crowe Qiang Liu Fumiko Axelrod Aaron K. Sato 《MABS-AUSTIN》2022,14(1)
110.