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Rosalind Aughwane Emma Ingram Edward D. Johnstone Laurent J. Salomon Anna L. David Andrew Melbourne 《黑龙江环境通报》2020,40(1):38-48
Objective
Magnetic resonance imaging (MRI) of placental invasion has been part of clinical practice for many years. The possibility of being better able to assess placental vascularization and function using MRI has multiple potential applications. This review summarises up-to-date research on placental function using different MRI modalities.Method
We discuss how combinations of these MRI techniques have much to contribute to fetal conditions amenable for therapy such as singletons at high risk for fetal growth restriction (FGR) and monochorionic twin pregnancies for planning surgery and counselling for selective growth restriction and transfusion conditions.Results
The whole placenta can easily be visualized on MRI, with a clear boundary against the amniotic fluid, and a less clear placental-uterine boundary. Contrasts such as diffusion weighted imaging, relaxometry, blood oxygenation level dependent MRI and flow and metabolite measurement by dynamic contrast enhanced MRI, arterial spin labeling, or spectroscopic techniques are contributing to our wider understanding of placental function.Conclusion
The future of placental MRI is exciting, with the increasing availability of multiple contrasts and new models that will boost the capability of MRI to measure oxygen saturation and placental exchange, enabling examination of placental function in complicated pregnancies. 相似文献3.
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G. E. Chalouhi M. Essaoui J. Stirnemann T. Quibel B. Deloison L. Salomon Y. Ville 《黑龙江环境通报》2011,31(7):637-646
Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins including twin-to-twin transfusion syndrome. The diagnosis is well established in overt clinical forms with the association of polyuric polyhydramnios and oliguric oligohydramnios. The best treatment of cases presenting before 26 weeks of gestion is fetoscopic laser ablation of the intertwin anastomoses on the chorionic plate. Although subjected to subtle variations, the core technique follows robust guidelines which could help understanding and acquiring the required skills and experience to perform this procedure. However appropriate and tailored hands-on training and appropriate perinatal set-up are critical not only for surgical management but also for the follow-up and management of related complications. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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We investigated the relative roles of natural factors and shoreline harvest leading to recent declines of the black leather chiton (Katharina tunicata) on the outer Kenai Peninsula, Alaska (U.S.A.). This intertidal mollusk is a strongly interacting grazer and a culturally important subsistence fishery for Sugpiaq (Chugach Alutiiq) natives. We took multiple approaches to determine causes of decline. Field surveys examined the significant predictors of Katharina density and biomass across 11 sites varying in harvest pressure, and an integrated analysis of archaeological faunal remains, historical records, traditional ecological knowledge, and contemporary subsistence invertebrate landings examined changes in subsistence practices through time. Strong evidence suggests that current spatial variation in Katharina density and biomass is driven by both human exploitation and sea otter (Enhydra lutris) predation. Traditional knowledge, calibrated by subsistence harvest data, further revealed that several benthic marine invertebrates (sea urchin, crab, clams, and cockles) have declined serially beginning in the 1960s, with reduced densities and sizes of Katharina being the most recent. The timing of these declines was coincident with changes in human behavior (from semi-nomadic to increasingly permanent settlement patterns, improved extractive technologies, regional commercial crustacean exploitation, the erosion of culturally based season and size restrictions) and with the reestablishment of sea otters. We propose that a spatial concentration in shoreline collection pressure through time, increased harvest efficiency, and the serial depletion of alternative marine invertebrate prey have led to intensified per capita predator impacts on Katharina and thus its recent localized decline. 相似文献
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Sociality in some birds, mammals, and social insects was suggested to have evolved through the lengthening and extension of
parental care behaviors to nondirect descendents. In these systems, group members care for young cooperatively and, thus,
increase the reproductive success of the breeders and fitness of the young. Parental care behaviors, such as regurgitation
feeding and matriphagy (consumption of the mother), occur in several subsocial and social spiders. However, it is not known
whether females in a colony cooperate in caring for the young of other females and whether such cooperative care improves
reproductive success. To answer this question, we created experimental colonies of the social spider Stegodyphus dumicola (Araneae, Eresidae), allowing only one female in a group to produce young, simulating reproductive skew occurring in nests
in nature. In this paper, we show for the first time that females of S. dumicola cooperate in providing regurgitated food for young of other females and are even eaten by those young. Young raised by a
group of females were larger and had greater survival than young raised only by their mother. Thus, fitness benefits from
raising broods cooperatively may have favored the evolution of sociality in spiders. 相似文献
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