Vitamin D dependent rickets type I

Vitamin D is present in two forms, ergocalciferol (vitamin D2) produced by plants and cholecalciferol (vitamin D3) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D], plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of 1,25(OH)2D from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the 1α-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D 1α-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of 1,25(OH)2D despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human 1α-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and 1α-hydroxylase mutations with clinical findings

Galactic center GeV gamma-ray excess from dark matter with gauged lepton numbers

The recently observed excess in gamma-ray signal near the Galactic center suggests that dark matter particles may annihilate into charged fermions that produce gamma-ray to be observed. In this paper, we consider a leptonic dark matter, which annihilates into the standard model leptons, $\mu^+ \mu^-$ and $\tau^+ \tau^-$, by the interaction of the gauged lepton number ${\rm U(1)}_{L_\mu-L_\tau}$ and fits the observed excess. Interestingly, the necessary annihilation cross section for the observed gamma-ray flux provides a good fit to the value for the relic abundance of dark matter. We identify the preferred parameter space of the model after taking the existing experimental constraints from the precision measurements including the muon $(g-2)$, tau decay, neutrino trident production, dark matter direct detection, LHC, and LEP experiments.Comment: 18 pages, 8 figures, references added, matches published versio

Clinical disease characteristics according to karyotype in Turner syndrome

Purpose : Turner syndrome (TS) is a disorder in which various anomalies can be accompanied, especially cardiovascular, renal, thyroid and auditory problems. The aim of this study is to identify the incidence of these disorders in patients with TS according to karyotype. Methods : We reviewed medical records of 90 patients with TS diagnosed by chromosomal analysis in 4 hospitals from Jan 1998 to Dec 2007. We evaluated these cases by prepared protocol of 4 medical problems. Results : The distribution of karyotype was 45,X (47.8%), mosaic pattern (34.4%) and structural aberration group (17.8 %). Renal anomalies, cardiovascular anomalies, thyroid disorders and auditory problems are accompanied in 4.4%, 10.0 %, 11.1% and 5.6%, respectively. 45,X group had renal anomalies (7.0%), cardiovascular anomalies (18.6%), thyroid disorders (9.3%) and auditory problems (11.6%). Mosaic group had renal anomalies (3.2%), thyroid disorders (12.9%), no cardiovascular anomalies and auditory problems. Structural aberration group had cardiovascular anomalies (6.3%), thyroid disorders (12.5%) and no other 2 problems. Patients with 45,X group had a significant higher incidence of cardiovascular anomalies (P=0.025). Conclusion : Our results indicate that there are differences clinically according to karyotype of TS, especially in incidence of cardiovascular anomalies

MicroRNA-762 is upregulated in human corneal epithelial cells in response to tear fluid and Pseudomonas aeruginosa antigens and negatively regulates the expression of host defense genes encoding RNase7 and ST2.

Mucosal surfaces regulate defenses against infection and excessive inflammation. We previously showed that human tears upregulated epithelial expression of genes encoding RNase7 and ST2, which inhibited Pseudomonas aeruginosa invasion of human corneal epithelial cells. Here, microRNA microarrays were used to show that a combination of tear fluid exposure (16 h) then P. aeruginosa antigens (3 h) upregulated miR-762 and miR-1207, and down-regulated miR-92 and let-7b (all > 2-fold) in human corneal epithelial cells compared to P. aeruginosa antigens alone. RT-PCR confirmed miR-762 upregulation ∼ 3-fold in tear-antigen exposed cells. Without tears or antigens, an antagomir reduced miR-762 expression relative to scrambled controls by ∼50%, increased expression of genes encoding RNase7 (∼80 %), ST2 (∼58%) and Rab5a (∼75%), without affecting P. aeruginosa internalization. However, P. aeruginosa invasion was increased > 3-fold by a miR-762 mimic which reduced RNase7 and ST2 gene expression. Tear fluid alone also induced miR-762 expression ∼ 4-fold, which was reduced by the miR-762 antagomir. Combination of tear fluid and miR-762 antagomir increased RNase7 and ST2 gene expression. These data show that mucosal fluids, such as tears, can modulate epithelial microRNA expression to regulate innate defense genes, and that miR-762 negatively regulates RNase7, ST2 and Rab5a genes. Since RNase7 and ST2 inhibit P. aeruginosa internalization, and are upregulated by tear fluid, other tear-induced mechanisms must counteract inhibitory effects of miR-762 to regulate resistance to bacteria. These data also suggest a complex relationship between tear induction of miR-762, its modulation of innate defense genes, and P. aeruginosa internalization

Understanding and Controlling the Morphology of Organic Thin Films

Display panels today open the door to the repository of knowledge, and their use is expanding from conventional home appliances to transparent, wearable and mobile devices. Organic semiconductors are a perfect candidate for this ubiquitous use of display panels since organics are flexible, transparent with high brightness and capable of good color rendering. The expanding outdoor use of organic devices poses questions whether: i) the devices are bright enough to be visible under daylight, and ii) the devices can withstand extreme conditions such as the interior of an automobile in the summer. Organic light emitting devices (OLEDs) achieved ~100% internal quantum efficiency with phosphorescence in 1998 [1], and since then the bottle neck for OLED brightness has been the outcoupling efficiency. The capability of organics to withstand severe conditions is closely related to their morphological stability. Thus, improving the outcoupling efficiency and controlling the morphology of OLEDs are the two crucial aspects in the future display technology. In this sense, this thesis mainly deals with the methods to improve the light outcoupling of OLEDs by morphological control. Also, methods for understanding organic film morphology are discussed. In this thesis, we demonstrate a measurement technology to obtain precise nanoscale information about the morphologies of several organic thin film structures using Fourier plane imaging microscopy (FIM). We use FIM to detect the orientation of molecular transition dipole moments from an extremely low density (i.e. small fractions of a monolayer) of luminescent dye molecules, which we call “morphology sensors.” The orientation of the sensor molecules is driven by the local film structure, and thus can be used to determine details of the host morphology without influencing it. We use symmetric planar phosphorescent dye molecules as the sensors that are deposited into the bulk of organic film hosts during the growth. Furthermore, we monitor morphological changes arising from thermal annealing of metastable organic films that are commonly employed in photonic devices. Methods to control the organic film morphology to improve the light outcoupling are also demonstrated. Here we control the orientation of Pt complex molecules during the growth of emissive layers by two different methods: modifying the molecular structure, and using structural templating. Pt complex dopant molecules whose structures are modified by adjusting the ligands show an approximately 20% increased fraction of horizontally aligned transition dipole moments compared to the original molecule while being diluted in the host matrix. Alternatively, we pre-deposit a highly ordered structural template layer, which results in a 60% increase in horizontally aligned transition dipole moments compared to the film deposited in the absence of the template. Finally, we employ a 2-dimensional transition metal dichalcogenides as the active luminescent layer due to its optimum emission profile for efficient outcoupling. Therefore, a hybrid light emitting device (LED) is fabricated employing a chemical-vapor-deposition grown, centimeter-scale monolayer of WS2 (mWS2), embedded within conductive organic layers. As a result, LEDs with an average external quantum efficiency of 0.3 ± 0.3% and with the highest efficiency of 1% were achieved. Also, we show that negatively charged excitons, also known as trions, are generated in the mWS2 with the injected current, causing an efficiency roll-off at high current densities.PHDElectrical and Computer EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169696/1/jongckim_1.pd