469 research outputs found
Cushing Syndrome in a 6-Month-Old Infant due to Adrenocortical Tumor
Cushing syndrome is rare in infancy and usually due to an adrenocortical tumor (ACT).
We report an infant with Cushing syndrome due to adrenocortical carcinoma. The patient presented at six months of age with a three-month history of growth failure, rapid weight gain, acne, and irritability. Physical examination showed obesity, hypertension, and Cushingoid features. Biochemical evaluation showed very high serum cortisol, mildly elevated testosterone, and suppressed ACTH. Abdominal MRI revealed a heterogeneous right adrenal mass extending into the inferior vena cava. Evaluation for metastases was negative. The tumor was removed surgically en bloc. Pathologic examination demonstrated low mitotic rate, but capsular and vascular invasion. She received no adjuvant therapy. Her linear growth has improved and Cushingoid features resolved. Hormonal markers and quarterly PET scans have been negative for recurrence 24 months postoperatively. In conclusion, adrenocortical neoplasms in children are rare, but should be considered in the differential diagnosis of Cushing syndrome
Assessing direct contributions of morphological awareness and prosodic sensitivity to children’s word reading and reading comprehension
We examined the independent contributions of prosodic sensitivity and morphological awareness to word reading, text reading accuracy, and reading comprehension. We did so in a longitudinal study of English-speaking children (N = 70). At 5 to 7 years of age, children completed the metalinguistic measures along with control measures of phonological awareness and vocabulary. Children completed the reading measures two years later. Morphological awareness, but not prosodic sensitivity made a significant independent contribution to word reading, text reading accuracy and reading comprehension. The effects of morphological awareness on reading comprehension remained after controls for word reading. These results suggest that morphological awareness needs to be considered seriously in models of reading development and that prosodic sensitivity might have primarily indirect relations to reading outcomes.
Keywords: Morphological Awareness; Prosody; Word Reading; Reading Comprehension
The effects of an increase in intensity during tapering on 1,500m running performance
We examined the effect of completing the final interval training session during a taper at either: i) race pace; or ii) faster than race pace, on 1,500 m running performance and neuromuscular performance. Ten trained runners (age 21.7 ± 3.0 years, height 182.9 ± 7.0 cm, body mass 73.4 ± 6.8 kg, personal best 1,500 m time 4:17.5 ± 0:26.9 min) completed two conditions, consisting of 7-d of regular training and a 7-d taper, separated by three weeks of training. In one condition, the taper was prescribed using prediction models based on the practices of elite British middle-distance runners, with the intensity of the final interval session being equal to 1,500 m race pace (RP). The taper was repeated in the HI condition, except the final interval session was completed at 115% of 1,500 m race pace. A 1,500 m treadmill time trial, measures of maximum voluntary isometric strength (MVC) and rate of force development (RFD) were completed before and after regular training and tapering. Performance was most likely improved after RP (mean ± 90% confidence limits, 10.1 ± 1.6 s), and possibly beneficial after HI (4.2 ± 12.0 s). Both MVC force (p = 0.002) and RFD (p = 0.02) were improved after tapering, without differences between conditions. A race-pace taper based on the practices of elite middle-distance runners is recommended to improve performance in young, sub-elite runners. The effect of this strategy with an increase in interval intensity is highly variable and should be implemented with caution
The Intermediate Filament Network in Cultured Human Keratinocytes Is Remarkably Extensible and Resilient
The prevailing model of the mechanical function of intermediate filaments in cells assumes that these 10 nm diameter filaments make up networks that behave as entropic gels, with individual intermediate filaments never experiencing direct loading in tension. However, recent work has shown that single intermediate filaments and bundles are remarkably extensible and elastic in vitro, and therefore well-suited to bearing tensional loads. Here we tested the hypothesis that the intermediate filament network in keratinocytes is extensible and elastic as predicted by the available in vitro data. To do this, we monitored the morphology of fluorescently-tagged intermediate filament networks in cultured human keratinocytes as they were subjected to uniaxial cell strains as high as 133%. We found that keratinocytes not only survived these high strains, but their intermediate filament networks sustained only minor damage at cell strains as high as 100%. Electron microscopy of stretched cells suggests that intermediate filaments are straightened at high cell strains, and therefore likely to be loaded in tension. Furthermore, the buckling behavior of intermediate filament bundles in cells after stretching is consistent with the emerging view that intermediate filaments are far less stiff than the two other major cytoskeletal components F-actin and microtubules. These insights into the mechanical behavior of keratinocytes and the cytokeratin network provide important baseline information for current attempts to understand the biophysical basis of genetic diseases caused by mutations in intermediate filament genes
Dispersal Routes and Habitat Utilization of Juvenile Atlantic Bluefin Tuna, Thunnus thynnus, Tracked with Mini PSAT and Archival Tags
Between 2005 and 2009, we deployed 58 miniature pop-up satellite archival tags (PSAT) and 132 implanted archival tags on juvenile Atlantic bluefin tuna (age 2–5) in the northwest Atlantic Ocean. Data returned from these efforts (n = 26 PSATs, 1 archival tag) revealed their dispersal routes, horizontal and vertical movements and habitat utilization. All of the tagged bluefin tuna remained in the northwest Atlantic for the duration observed, and in summer months exhibited core-use of coastal seas extending from Maryland to Cape Cod, MA, (USA) out to the shelf break. Their winter distributions were more spatially disaggregated, ranging south to the South Atlantic Bight, northern Bahamas and Gulf Stream. Vertical habitat patterns showed that juvenile bluefin tuna mainly occupied shallow depths (mean = 5–12 m, sd = 15–23.7 m) and relatively warm water masses in summer (mean = 17.9–20.9°C, sd = 4.2–2.6°C) and had deeper and more variable depth patterns in winter (mean = 41–58 m, sd = 48.9–62.2 m). Our tagging results reveal annual dispersal patterns, behavior and oceanographic associations of juvenile Atlantic bluefin tuna that were only surmised in earlier studies. Fishery independent profiling from electronic tagging also provide spatially and temporally explicit information for evaluating dispersals rates, population structure and fisheries catch patterns
Abrupt Ice Age Shifts in Southern Westerlies and Antarctic Climate Forced from the North
The Southern Hemisphere (SH) mid-latitude westerly winds play a central role in the global climate system via Southern Ocean upwelling, carbon exchange with the deep ocean, Agulhas Leakage, and Antarctic ice sheet stability. Meridional shifts in the SH westerlies have been hypothesized in response to abrupt North Atlantic Dansgaard-Oeschger (DO) climatic events of the last ice age, in parallel with the well-documented shifts of the intertropical convergence zone. Shifting moisture pathways to West Antarctica are consistent with this view, but may represent a Pacific teleconnection pattern. The full SH atmospheric-circulation response to the DO cycle, as well as its impact on Antarctic temperature, have so far remained unclear. Here we use five volcanically-synchronized ice cores to show that the Antarctic temperature response to the DO cycle can be understood as the superposition of two modes: a spatially homogeneous oceanic “bipolar seesaw” mode that lags Northern Hemisphere (NH) climate by about 200 years, and a spatially heterogeneous atmospheric mode that is synchronous with NH abrupt events. Temperature anomalies of the atmospheric mode are similar to those associated with present-day Southern Annular Mode (SAM) variability, rather than the Pacific South America (PSA) pattern. Moreover, deuterium excess records suggest a zonally coherent migration of the SH westerlies over all ocean basins in phase with NH climate. Our work provides a simple conceptual framework for understanding the circum-Antarctic temperature response to abrupt NH climate change. We provide observational evidence for abrupt shifts in the SH westerlies, with ramifications for global ocean circulation and atmospheric CO₂. These coupled changes highlight the necessity of a global, rather than a purely North Atlantic, perspective on the DO cycle
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