8,335 research outputs found

    Sarcoidosis presenting as granulomatous myositis in a 16-year-old adolescent

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    BACKGROUND: Sarcoidosis is a multi-system disease characterized by the presence of non-caseating epithelioid granulomas in affected tissues, including skeletal muscle. These organized collections of immune cells have important pathophysiologic action including cytokine production leading to inflammation as well as enzymatic conversion of cholecalciferol to calcitriol via 1-α hydroxylase. There are limited reports of isolated granulomatous myositis causing hypercalcemia in pediatric patients. Our patient uniquely presented with symptoms from hypercalcemia and renal insufficiency caused by an overwhelming burden of granulomatous myositis in her lower extremities, but was otherwise asymptomatic. CASE PRESENTATION: A 16 year old Caucasian female presented with protracted symptoms of fatigue, nausea and prominent weight loss with laboratory evidence of hypercalcemia and renal insufficiency. She lacked clinical and physical findings of arthritis, weakness, rash, uveitis, fever, lymphadenopathy or respiratory symptoms. After extensive negative investigations, re-examination yielded subtle soft tissue changes in her lower extremities, with striking MRI findings of extensive myositis without correlative weakness or serum enzyme elevation. Biopsy showed the presence of non-caseating epithelioid granulomas and calcium oxalate crystals. The patient responded well to prednisone and methotrexate but relapsed with weaning of steroids. She reachieved remission with addition of adalimumab. CONCLUSIONS: Sarcoidosis should be considered in patients presenting with symptomatic hypercalcemia with no apparent causes and negative routine workup. The absences of decreased muscle strength or elevated muscle enzymes do not preclude the diagnosis of granulomatous myositis

    Bilateral acute Ocular Ischemic Syndrome following head and neck radiation

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    Previous literature has established a clear correlation between radiation therapy (RT) to the head and neck leading to aggressive atherosclerosis of the carotid arteries and subsequent increased risk for ischemic stroke. Stenosis of carotid arteries can lead to Ocular Ischemic syndrome (OIS). We present a case of acute bilateral OIS following head and neck RT for left tonsillar squamous cell carcinoma (SCC) in a 64 year-old Caucasian male. Routine large vessel cerebrovascular screening following head and neck radiotherapy should be considered as a means of potentially mitigating future stroke risk through initiation of medical therapy and interventional modalities as a means of primary prevention. In addition to large vessel screening by carotid duplex ultrasound, it may also be pertinent to consider further evaluation with more detailed medium and small vessel imaging through CT angiography in select cases

    The K20 survey. IV. The redshift distribution of Ks<20 galaxies: a test of galaxy formation models

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    We present the redshift distribution of a complete sample of 480 galaxies with Ks<20 distributed over two independent fields covering a total area of 52 arcmin^2. The redshift completeness is 87% and 98% respectively with spectroscopic and high-quality and tested photometric redshifts. The redshift distribution of field galaxies has a median redshift z_{med}\sim 0.80, with \sim 32% and \sim 9% of galaxies at z>1 and z>1.5 respectively. A ``blind'' comparison is made with the predictions of a set of the most recent LambdaCDM hierarchical merging and pure luminosity evolution (PLE) models. The hierarchical merging models overpredict and underpredict the number of galaxies at low-z and high-z respectively, whereas the PLE models match the median redshift and the low-z distribution, still being able to follow the high-z tail of N(z). We briefly discuss the implications of this comparison and the possible origins of the observed discrepancies. We make the redshift distribution publicly available.Comment: 5 pages, 5 figures, to appear in Astronomy & Astrophysics Letter

    The metabolic inter-relationships between changes in waist circumference, triglycerides, insulin sensitivity and small, dense low-density lipoprotein particles with acute weight loss in clinically obese children and adolescents.

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    OBJECTIVE: Small, dense low-density lipoprotein (LDL) particles are highly atherogenic and strongly associated with obesity-related dyslipidemia. The metabolic inter-relationships between weight loss induced changes in waist circumference, triglycerides, insulin sensitivity and small-dense LDL particles in clinically obese children and adolescents have not been studied. METHODS: Seventy-five clinically obese boys and girls (standardized body mass index 3.07 ± 0.59, aged 8-18 years) were recruited. Anthropometric, body composition and cardiometabolic risk factors were measured pre- and post-weight loss. RESULTS: There were highly significant reductions in anthropometric, body composition and cardiometabolic risk factors. Triglyceride change was positively correlated with LDL peak particle density and percentage LDL pattern B changes (relative abundance of small, dense LDL particles). Multiple regression analyses showed that changes in triglyceride concentration accounted for between 24 and 18% of the variance in LDL peak particle density and percentage LDL pattern B change, respectively. Changes in waist circumference and insulin sensitivity did not predict these changes in LDL characteristics. CONCLUSION: Acute and highly significant weight loss significantly decreased LDL peak particle density and percentage LDL pattern B. The change in triglycerides was a strong predictor of LDL peak particle density and percentage LDL pattern B change

    The Large-scale and Small-scale Clustering of Lyman-Break Galaxies at 3.5 < z< 5.5 from the GOODS survey

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    We report on the angular correlation function of Lyman-break galaxies (LBGs) at z~4 and 5 from deep samples obtained from the Great Observatories Deep Origins Survey (GOODS). Similar to LBGs at z~3, the shape of w(theta) of the GOODS LBGs is well approximated by a power-law with slope beta~0.6 at angular separation theta > 10 arcsec. The clustering strength of z~4, 5 LBGs also depends on the rest-frame UV luminosity, with brighter galaxies more strongly clustered than fainter ones, implying a general correlation between halos' mass and LBGs' star-formation rate. At smaller separations, w(theta) of deep samples significantly exceeds the extrapolation of the large-scale power-law fit, implying enhanced spatial clustering at scales r < 1 Mpc. We also find that bright LBGs statistically have more faint companions on scales theta < 20 arcsec than fainter ones, showing that the enhanced small-scale clustering is very likely due to sub-structure, namely the fact that massive halos can host multiple galaxies. A simple model for the halo occupation distribution and the CDM halo mass function reproduce well the observed w(theta). The scaling relationship of the clustering strength with volume density and with redshift is quantitatively consistent with that of CDM halos. A comparison of the clustering strength of three samples of equal luminosity limit at z ~ 3, 4 and 5 shows that the LBGs at z~5 are hosted in halos about one order of magnitude less massive than those in the lower redshift bins, suggesting that star-formation was more efficient at higher-redshift.Comment: replaced with the version accepted for publication in ApJ. 46 pages, 10 figures; minor changes to text, one subsection adde

    High levels of childhood obesity observed among 3- to 7-year-old New Zealand Pacific children is a public health concern.

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    This cross-sectional, community-based survey was designed to assess attained growth and body composition of 3- to 7-y-old Pacific children (n = 21 boys and 20 girls) living in Dunedin, New Zealand, and to examine nondietary factors associated with the percentage of body fat. Fat mass, lean tissue mass and the percentage of body fat were measured using dual energy X-ray absorptiometry. One trained anthropometrist also measured height, weight, skinfolds (triceps, subscapular) and circumferences (mid-upper arm, chest, waist, calf). Compared with the National Center for Health Statistics and National Health and Examination Surveys I and II reference data, these Pacific children were tall and heavy for their age with high arm-muscle-area-for-height. Median (quartiles) Z-scores for height and BMI-for-age and arm-muscle-area-for-height were 1.33 (0.60, 2.15), 1.20 (0.74, 4.43) and 1.09 (0.63, 1.85), respectively. Their median (quartile) percentage of body fat was 21.8% (15.0, 35.5) of which 38.5% was located in the trunk. The estimated percentage of children classified as obese ranged from 34 to 49% depending on the criterion used. Over 60% of the children had levels of trunk fat above 1 SD of reported age- and sex-specific Z-scores for New Zealand children. The nondietary factors examined (hours of television viewing and hours playing organized sports, as reported by parents) were not associated with variations in the percentage of body fat, after adjusting for age, sex and birth weight. These extremely high levels of obesity and truncal fat among very young New Zealand children will have major public health implications as these children age

    Spitzer Observations of Red Galaxies: Implication for High-Redshift Star Formation

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    My colleagues and I identified distant red galaxies (DRGs) with J-K>2.3 mag in the GOODS-S field. These galaxies reside at z~1-3.5, (=2.2) and based on their ACS (0.4-1 micron), ISAAC (1-2.2 micron), and IRAC (3-8 micron) photometry, they typically have inferred stellar masses > 10^11 solar masses. Interestingly, more than 50% of these objects have 24 micron flux densities >50 micro-Jy. Attributing the IR emission to star-formation implies SFRs of \~100-1000 solar masses per year. As a result, galaxies with stellar masses >10^11 solar masses have specific SFRs equal to or exceeding the global value at z~1.5-3. In contrast, galaxies with >10^11 solar masses z~0.3-0.75 have specific SFRs less than the global average, and more than an order of magnitude lower than that for massive DRGs at z~1.5-3. Thus, the bulk of star formation in massive galaxies is largely complete by z~1.5. The red colors and large inferred stellar masses in the DRGs suggest that much of the star formation in these galaxies occurred at redshifts z>5-6. Using model star-formation histories that match the DRG colors and stellar masses at z~2-3, and measurements of the UV luminosity density at z>5-6, we consider what constraints exist on the stellar initial mass function in the progenitors of the massive DRGs at z~2-3.Comment: To appear in the proceedings of UC Irvine May 2005 workshop on "First Light & Reionization", eds. E. Barton & A. Cooray, New Astronomy Reviews. 10 pages, 5 figure

    Bilateral acute Ocular Ischemic Syndrome following head and neck radiation

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    Previous literature has established a clear correlation between radiation therapy (RT) to the head and neck leading to aggressive atherosclerosis of the carotid arteries and subsequent increased risk for ischemic stroke. Stenosis of carotid arteries can lead to Ocular Ischemic syndrome (OIS). We present a case of acute bilateral OIS following head and neck RT for left tonsillar squamous cell carcinoma (SCC) in a 64 year-old Caucasian male. Routine large vessel cerebrovascular screening following head and neck radiotherapy should be considered as a means of potentially mitigating future stroke risk through initiation of medical therapy and interventional modalities as a means of primary prevention. In addition to large vessel screening by carotid duplex ultrasound, it may also be pertinent to consider further evaluation with more detailed medium and small vessel imaging through CT angiography in select cases

    The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling Problem

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    We present an analysis of the star formation history (SFH) of a field near the half light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest main sequence turn-off, allowing a time resolution at the oldest ages of ~1 Gyr. Our analysis shows that the SFH of the observed field in IC 1613 is consistent with being constant over the entire lifetime of the galaxy. These observations rule out an early dominant episode of star formation in IC 1613. We compare the SFH of IC 1613 with expectations from cosmological models. Since most of the mass is in place at early times for low mass halos, a naive expectation is that most of the star formation should have taken place at early times. Models in which star formation follows mass accretion result in too many stars formed early and gas mass fractions which are too low today (the "over-cooling problem"). The depth of the present photometry of IC 1613 shows that, at a resolution of ~1 Gyr, the star formation rate is consistent with being constant, at even the earliest times, which is difficult to achieve in models where star formation follows mass assembly.Comment: 13 pages, 12 figures, accepted for publication in the Ap
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