bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeted disruption of the hepcidin 1 gene results in severe hemochromatosis
Authors: Lesbordes-Brion Jeanne-Claire , Viatte Lydie , Bennoun Myriam , Lou Dan-Qing , Ramey Guillemette , Houbron Christophe , Hamard Ghislaine , Kahn Axel , Vaulont Sophie 
Published: March 2006

Abstract
We previously reported that mice made deficient for the transcriptional factor USF2 fail to express hepcidin 1 and hepcidin 2 genes as a consequence of targeted disruption of the Usf2 gene lying just upstream in the locus. These mice developed an iron overload phenotype with excess iron deposition in parenchymal cells and decreased reticuloendothelial iron. At that time, although the role of USF2 was still confounding, we proposed for the first time the role of hepcidin as a negative regulator of iron absorption and iron release from macrophages. Accordingly, we subsequently demonstrated that hyperexpression of hepcidin 1, but not hepcidin 2, resulted in a profound hyposideremic anemia. To analyze the consequences of hepcidin 1 deletion on iron metabolism without any disturbance due to USF2 deficiency, we disrupted the hepcidin 1 gene by targeting almost all the coding region. Confirming our prior results, Hepc1–/– mice developed early and severe multivisceral iron overload, with sparing of the spleen macrophages, and demonstrated increased serum iron and ferritin levels as compared with their controls.
Lymphoid interstitial pneumonia: clinical features, associations and prognosis
Authors: Cha S-I. , Fessler M. B. , Cool C. D. , Schwarz M. I. , Brown K. K. 
Published: March 2006

Lymphoid interstitial pneumonia (LIP) is rare and its clinical course incompletely described. The aim of this study was to examine the clinical features, associations and prognosis of surgical lung biopsy-proven LIP. The study group consisted of 15 subjects encountered over a 14-yr period.The majority of subjects were females (n = 11) and the mean age was 47 yrs (range 17–78 yrs). Underlying systemic immune disorders were frequent, including Sjögren's syndrome (n = 8), rheumatoid arthritis, systemic lupus erythematosus, polymyositis, common variable immunodeficiency and dysproteinaemia. Only three patients were classified as “idiopathic”. Presenting symptoms were dominated by dyspnoea and cough. Restrictive physiology, reduced diffusion capacity (62.5±18.4% predicted) and bronchoalveolar lavage lymphocytosis (30.5±29.1% pred) were noted. Thirteen patients received corticosteroid therapy. Of the nine whose response could be assessed, four showed clinical improvement and four were stable. Overall, median survival was 11.5 yrs. Of the seven patients who died, respiratory problems were the primary cause of death in three. Conversion to lymphoma was not identified.In conclusion, histopathological lymphoid interstitial pneumonia is commonly associated with immune system dysregulation, with idiopathic lymphoid interstitial pneumonia being extremely rare. Clinical stability or improvement with corticosteroids can be expected; however, survival remains impaired.
Allergic lung inflammation induces pulmonary vascular hyperresponsiveness
Authors: Witzenrath M. , Ahrens B. , Kube S. M. , Hocke A. C. , Rosseau S. , Hamelmann E. , Suttorp N. , Schütte H. 
Published: March 2006

Pulmonary arterial vasoconstriction is an important early component of pulmonary hypertension. Inflammatory mechanisms play a prominent role in the pathogenesis of pulmonary hypertension. The present authors investigated the potential role of acute allergic lung inflammation for alterations in pulmonary haemodynamics.BALB/c mice were intraperitoneally sensitised to ovalbumin and challenged by ovalbumin inhalation. Subsequently, lungs were ventilated and perfusedex vivo, and pulmonary arterial pressure (Ppa) was continuously monitored.Isolated perfused lungs of allergen-sensitised and -challenged mice showed five-fold enhanced Pparesponses to serotonin, which is reported to be a significant contributor to pulmonary hypertension in humans. This increase inPpawas abolished by the serotonin receptor-2A antagonist ketanserin, but not the serotonin receptor-1B antagonist GR127935. Intracellular signalling to serotonin involved phosphatidylcholine-specific phospholipase C and protein kinase C, as well as Rho-kinase, as assessed by employing the specific inhibitors D609, bisindolylmaleimide and Y27632, respectively. In addition to serotonin, impressively enhancedPpaincreases in allergic lungs were also evoked by the thromboxane receptor agonist U46619, angiotensin II and endothelin-1.In conclusion, allergic lung inflammation was accompanied by impressive pulmonary vascular hyperresponsiveness. These results suggest a possible role for allergic inflammation in the development of pulmonary arterial hypertension.
Ventilation inhomogeneity in α1-antitrypsin-deficient emphysema
Authors: Fregonese L. , van Veen H. P. A. A. , Sterk P. J. , Stolk J. 
Published: March 2006

The slope of phase III of the single-breath nitrogen wash-out test (sbN2-test) measures ventilation inhomogeneity and, in smokers, is strongly associated with small airways pathology. The present authors aimed to study ventilation inhomogeneity in emphysema related to type Z α1-antitrypsin (AAT) and to assess its relationship with indices of parenchymal damage and airways obstruction.A total of 18 subjects, consisting of ex-smokers with type Z AAT and emphysema (confirmed by computed tomography scan), were studied in a cross-sectional design. Post-bronchodilation flow–volume curves and gas transfer parameters were measured; sbN2-test curves were obtained and the slope of phase III was determined.The mean value of the slope (4.6±1.3% N2·L-1) was higher than reference values +2sd; it was significantly correlated with the transfer factor of the lung for carbon monoxide (R =  -0.75) and the transfer coefficient of the lung for carbon monoxide (R =  −0.58), but not with airways obstruction. There was no correlation between phase III slope values and cumulative smoking.In patients with type Z α1-antitrypsin emphysema, the increased ventilation inhomogeneity predominantly reflects parenchymal abnormalities, demonstrating that measurement of airways obstruction is not sufficient to characterise the disease. Determination of the sensitivity of the single-breath nitrogen wash-out test slope in detecting disease progression may give complementary information to spirometry.
Kidnapping of chicks in emperor penguins: a hormonal by-product?
Authors: Angelier Frédéric , Barbraud Christophe , Lormée Hervé , Prud'homme François , Chastel Olivier 
Published: March 2006

SUMMARY
The function and causes of kidnapping juveniles are little understood because individuals sustain some breeding costs to rear an unrelated offspring. Here we focus on the proximal causes of this behaviour in emperor penguins (Aptenodytes forsteri), whose failed breeders often kidnap chicks. We experimentally tested the hypothesis that kidnapping behaviour was the result of high residual levels of prolactin (PRL), a hormone involved in parental behaviour. Penguins with artificially decreased PRL levels by bromocriptine administration kidnapped chicks less often than control penguins. Within the bromocriptine treated group, kidnapping behaviour was not totally suppressed and the probability of kidnapping a chick was positively correlated to PRL levels measured before treatment. During breeding, emperor penguins have to forage in remote ice-free areas. In these birds, PRL secretion is poorly influenced by chick stimuli and has probably evolved to maintain a willingness to return to the colony after a long absence at sea. Therefore, penguins that have lost their chick during a foraging trip still maintain high residual PRL levels and this, combined with colonial breeding,probably facilitates kidnapping. We suggest that kidnapping in non-cooperative systems may result from a hormonal byproduct of a reproductive adaptation to extreme conditions.
Passive mechanical properties of legs from running insects
Authors: Dudek Daniel M. , Full Robert J. 
Published: March 2006

SUMMARYWhile the dynamics of running arthropods have been modeled as a spring-mass system, no such structures have been discovered that store and return energy during bouncing. The hindleg of the cockroach Blaberus discoidalis is a good candidate for a passive, vertical leg spring because its vertically oriented joint axes of rotation limit the possibility of active movements and contributions of muscle properties. We oscillated passive legs while measuring force to determine the leg's dynamic, mechanical properties. The relative dimensionless stiffness of an individual cockroach leg was equal to that estimated for a single leg of a biped or quadruped. Leg resilience ranged from 60 to 75%, affording the possibility that the leg could function as a spring to store and return the mechanical energy required to lift and accelerate the center of mass. Because hysteresis was independent of oscillation frequency,we rejected the use of a Voigt model – a simple spring in parallel with a viscous damper. A hysteretic damping model fit the cockroach leg force–displacement data over a wide range of frequencies and displacement using just two parameters. Rather than simply acting as a spring to minimize energy, we hypothesize that legs must manage both energy storage and absorption for rapid running to be most effective.
Temporal pattern cues in vibrational risk assessment by embryos of the red-eyed treefrog, Agalychnis callidryas
Authors: Warkentin Karen M. , Caldwell Michael S. , McDaniel J. Gregory 
Published: March 2006

SUMMARY
The embryos of red-eyed treefrogs, Agalychnis callidryas, use vibrations transmitted through their arboreal egg clutch to cue escape hatching behavior when attacked by egg-eating snakes. Hatching early increases the risk of predation in the water, so embryos should avoid it unless they are in danger. We exposed egg clutches to intermittent vibrations with different combinations of vibration duration and spacing to examine the role of simple temporal pattern cues in the escape hatching response. Stimuli were bursts of synthetic white noise from 0 to 100 Hz, including the range of frequencies with substantial energy in snake attacks, and had approximately rectangular amplitude envelopes. Embryos hatched in response to a small range of temporal patterns and not in response to many others, rather than hatching to most vibrations except for certain patterns perceived as safe. Neither cycle length nor duty cycle predicted hatching response, except at extreme values where no hatching occurred; the highest energy stimuli elicited little or no hatching. Both vibration duration and inter-vibration interval strongly affected the hatching response. The highest levels of hatching were to durations of 0.5 s combined with intervals of 1.5–2.5 s, and hatching decreased gradually with increasing difference of either duration or interval from these most effective stimuli. Vibration duration and interval appear to function as two necessary elements of a composite cue, rather than as redundant cues. This increases response specificity and reduces the range of stimuli that elicit hatching, likely reducing the chance of hatching unnecessarily in a benign disturbance. Vibration-cued hatching in A. callidryas embryos offers an opportunity to experimentally assess the behavioral decision rules underlying an effective and costly anti-predator defense.
Heterothermy of free-living Arabian sand gazelles (Gazella subgutturosa marica) in a desert environment
Authors: Ostrowski Stéphane , Williams Joseph B. 
Published: March 2006

SUMMARYTo test whether free-living desert ungulates employ heterothermy to reduce water loss, we measured core body temperature (Tb) of six free-living Arabian sand gazelles (Gazella subgutturosa marica), a small desert antelope (12–20 kg) that lives in the deserts of Saudi Arabia, where air temperature (Ta) often exceeds 40°C. We found that the mean daily Tb varied by 2.6±0.8°C during summer (June–July) and 1.7±0.3°C during winter (January–February); over both seasons, mean Tb was 39.5±0.2°C. During the day, in summer, Tb increased by more than 2°C when Ta&gt;Tb and declined at night when Ta&lt;Tb, suggesting that gazelles stored heat during day and dissipated it by non evaporative means during night. The minimum Tb was lower in summer(38.2±0.5°C) than in winter (38.6±0.3°C) despite the fact that the gradient between Tb and Ta was larger and solar radiation was lower in winter. Correlation between daily variation of Tb and mean,maximal Tas were significant in summer, but not in winter. To dissipate the amount of heat stored by gazelles would require an evaporative water loss of 33.5 ml H2O day–1 in summer and 23.2 ml H2O day–1 in winter.We tested whether the amplitude of daily variation in Tb was influenced by the level of water provided to six captive sand gazelles maintained under controlled conditions in summer. The daily amplitude of Tb was increased by 1.4°C when gazelles were denied drinking water but supplied with pre-formed water in food, and by 1.1°C when they were denied both water and food. Gazelles denied only drinking water increased the amplitude of variation in Tb, whereas when denied both food and water, they seemed to undergo a dehydration-hyperthermia, with increased mean and maximal Tb values but no decrease of minimal Tb.Free-ranging and captive gazelles surviving on pre-formed water in natural food used heterothermy during summer with no elevation of plasma osmolality,indicating that they were not in a state of dehydration. Our data on variation in Tb of gazelles provide an example of a small desert ungulate employing heterothermy to reduce evaporative water loss that would otherwise be required to maintain normothermic Tb.
Median fin function in bluegill sunfishLepomis macrochirus:streamwise vortex structure during steady swimming
Authors: Tytell Eric D. 
Published: March 2006

SUMMARYFishes have an enormous diversity of body shapes and fin morphologies. From a hydrodynamic standpoint, the functional significance of this diversity is poorly understood, largely because the three-dimensional flow around swimming fish is almost completely unknown. Fully three-dimensional volumetric flow measurements are not currently feasible, but measurements in multiple transverse planes along the body can illuminate many of the important flow features. In this study, I analyze flow in the transverse plane at a range of positions around bluegill sunfish Lepomis macrochirus, from the trailing edges of the dorsal and anal fins to the near wake. Simultaneous particle image velocimetry and kinematic measurements were performed during swimming at 1.2 body lengths s–1 to describe the streamwise vortex structure, to quantify the contributions of each fin to the vortex wake, and to assess the importance of three-dimensional flow effects in swimming.Sunfish produce streamwise vortices from at least eight distinct places,including both the dorsal and ventral margins of the soft dorsal and anal fins, and the tips and central notched region of the caudal fin. I propose a three-dimensional structure of the vortex wake in which these vortices from the caudal notch are elongated by the dorso-ventral cupping motion of the tail, producing a structure like a hairpin vortex in the caudal fin vortex ring. Vortices from the dorsal and anal fin persist into the wake, probably linking up with the caudal fin vortices. These dorsal and anal fin vortices do not differ significantly in circulation from the two caudal fin tip vortices. Because the circulations are equal and the length of the trailing edge of the caudal fin is approximately equal to the combined trailing edge length of the dorsal and anal fins, I argue that the two anterior median fins produce a total force that is comparable to that of the caudal fin. To provide additional detail on how different positions contribute to total force along the posterior body, the change in vortex circulation as flow passes down the body is also analyzed. The posterior half of the caudal fin and the dorsal and anal fins add vortex circulation to the flow, but circulation appears to decrease around the peduncle and anterior caudal fin. Kinematic measurements indicate that the tail is angled correctly to enhance thrust through this interaction. Finally, the degree to which the caudal fin acts like a idealized two-dimensional plate is examined: approximately 25% of the flow near the tail is accelerated up and down, rather than laterally, producing wasted momentum,a loss not present in ideal two-dimensional theories.
Surface Texture Analysis of Artificial Disks Wear-Tested under Different Conditions and Comparison to a Retrieved Implant
Authors: Pare PE , Chan FW , Buchholz P , Kurtz S , McCombe P 
Published: March 2006

Abstract
Total disk arthroplasty is growing in popularity and becoming an alternative to fusion for the treatment of some degenerative disk diseases. To date, there is little consensus regarding the appropriate in vitro techniques with which to evaluate the biotribological properties of these devices. The current study evaluated the surface texture and topography of lumbar metal-on-metal artificial disks tested in a spine wear simulator compared to an explanted device after twelve months in situ. Six implants were tested under a constant load and unidirectional flexion-extension motion as defined by the ASTM standard guide. One implant was tested under a variable load using a combination of flexion-extension, lateral bending, and axial rotation as specified by the ISO standard. While the retrieved disk retained its initial mirror-like surface finish, implants tested under unidirectional motion were severely damaged by abrasive wear resulting in a significant increase in roughness. The implant tested under combined motions exhibited a multi-directional wear scar with limited surface damage. Although only a single retrieved implant was characterized, the current study suggests that wear testing under unidirectional motion may not produce clinically-relevant surface morphology of metal-on-metal artificial disks.
Observational Study on Fall Trends in Snowboarders
Authors: Cooper N , Greenwald RM 
Published: March 2006

AbstractSnowboarding has distinctly different injury patterns compared with traditional alpine skiing. Injuries occur more frequently in the upper extremity and less frequently in the knees compared to alpine skiing. Snowboarding continues to evolve as a sport, with active participation at all age and experience levels, and on different terrain including slopes, pipes, and terrain parks. An observational study of snowboarders at one U.S. and one Austrian ski resort was conducted during the 2004–05 season to investigate fall trends in a snowboarding population. The purpose of the study was to quantify the incidence of falling, what anatomical structure impacted during a fall, fall direction, and helmet usage as a function of age, gender, ability level, and terrain. Two categories of terrain were identified; standard slopes and terrain parks including half-pipes. Children and adults fall twice as often as youths and young adults. Beginners fall approximately six times more often than advanced snowboarders, and average more than one fall per beginner per run. Runs in the pipe and in a terrain park resulted in a fall 34 and 20 % of the time, respectively. Terrain and experience dictated which body part impacted the snow surface. For beginners, 72 % of all falls were onto the hands. For more experienced participants in the half-pipe or in a terrain park, 50 % of falls were onto the boarder's back or bottom. Helmet use for snowboarders was slightly greater than 50 %. Children were most likely to use a helmet (&gt;90 %), while less than 40 % of young adults used helmets. These observational data will be expanded and combined with injury data to quantify injury risk in the sport of snowboarding as a function of key demographics and environmental variables.
Evaluating Redband Trout Habitat in Sagebrush Desert Basins in Southwestern Idaho
Authors: Zoellick Bruce W. , Cade Brian S. 
Published: March 2006

Abstract
We estimated abundance quantiles of redband trout Oncorhynchus mykiss gairdneri relative to five site-specific habitat variables (stream shading, bank cover, bank stability, fine sediment in the stream substrate, and cover for adults) and one landscape variable (distance from stream headwaters) on 30 streams in southwestern Idaho during 1993–1998. In addition, the five site-specific habitat variables were used to calculate a habitat suitability rating (HSR) used by the U.S. Bureau of Land Management to determine habitat quality of sagebrush desert streams for redband trout. Variation in abundance increased significantly with increasing HSR; the highest abundances were only found with high HSRs, indicating that the HSR model correctly predicted habitat quality for redband trout. However, a model that consisted of stream shade, distance from stream headwaters, and their interaction best predicted redband trout density, explaining 36% of the variation in adult density in sagebrush desert basin streams; stream shade explained most of the variation in redband trout density. When habitat quality was modeled on shade alone, the precision in predicting adult redband trout density was similar to that of the HSR model, as evaluated with tolerance intervals that contained 80% of future observations of redband trout density with 95% confidence. Increasing stream shade in the uppermost 50 km of a stream would result in the greatest increase in redband trout density. We recommend that land managers primarily evaluate the habitat quality of sagebrush desert streams by quantifying the amount of stream shade provided by riparian shrubs and trees. Use of a multivariable habitat model should be retained for desert streams where shade from riparian plant communities is limited.
Scale Pattern Analysis Discriminates Atlantic Salmon by River Reach Rearing Origin
Authors: Haas-Castro Ruth E. , Sheehan Timothy F. , Cadrin Steven X. , Trial Joan G. 
Published: March 2006

Abstract
Scale pattern analysis was used to discriminate among juvenile Atlantic salmon Salmo salar reared in different reaches of the Narraguagus River basin. Measurements of parr scales collected during 1990–1999 were used in a principal components analysis and to create linear discriminant functions for seven geographic strata and three river basin strata groups reflecting natural habitat breaks and Atlantic salmon management regimens. Discriminant functions were calculated with both pooled and annual data. Sufficient differentiation existed among rearing habitats of different reaches (or between geographically grouped reaches) in the Narraguagus River basin, particularly for tributary habitats, to allow discrimination to various degrees of possible use in management.