474 research outputs found

    Anomalous Origin of the Subclavian Artery Associated with Phocomelia

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    A hitherto unreported association between anomalous origin of the right subclavian artery and phocomelia of theΒ right arm is described. The aetiology of phocomelia is briefly reviewed and the possible casual relajonship or association between phocomelia and the disturbance in vascular supply to the limb is discussed.S. Afr. Med. J., 45, 1397 (1971

    In Vivo Activation of the Intracrine Vitamin D Pathway in Innate Immune Cells and Mammary Tissue during a Bacterial Infection

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    Numerous in vitro studies have shown that toll-like receptor signaling induces 25-hydroxyvitamin D3 1Ξ±-hydroxylase (1Ξ±-OHase; CYP27B1) expression in macrophages from various species. 1Ξ±-OHase is the primary enzyme that converts 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Subsequently, synthesis of 1,25(OH)2D3 by 1Ξ±-OHase in macrophages has been shown to modulate innate immune responses of macrophages. Despite the numerous in vitro studies that have shown 1Ξ±-OHase expression is induced in macrophages, however, evidence that 1Ξ±-OHase expression is induced by pathogens in vivo is limited. The objective of this study was to evaluate 1Ξ±-OHase gene expression in macrophages and mammary tissue during an in vivo bacterial infection with Streptococcus uberis. In tissue and secreted cells from the infected mammary glands, 1Ξ±-OHase gene expression was significantly increased compared to expression in tissue and cells from the healthy mammary tissue. Separation of the cells by FACS9 revealed that 1Ξ±-OHase was predominantly expressed in the CD14+ cells isolated from the infected mammary tissue. The 24-hydroxylase gene, a gene that is highly upregulated by 1,25(OH)2D3, was significantly more expressed in tissue and cells from the infected mammary tissue than from the healthy uninfected mammary tissue thus indicating significant local 1,25(OH)2D3 production at the infection site. In conclusion, this study provides the first in vivo evidence that 1Ξ±-OHase expression is upregulated in macrophages in response to bacterial infection and that 1Ξ±-OHase at the site of infection provides 1,25(OH)2D3 for local regulation of vitamin D responsive genes

    Observation of the Fractional Quantum Hall Effect in Graphene

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    When electrons are confined in two dimensions and subjected to strong magnetic fields, the Coulomb interactions between them become dominant and can lead to novel states of matter such as fractional quantum Hall liquids. In these liquids electrons linked to magnetic flux quanta form complex composite quasipartices, which are manifested in the quantization of the Hall conductivity as rational fractions of the conductance quantum. The recent experimental discovery of an anomalous integer quantum Hall effect in graphene has opened up a new avenue in the study of correlated 2D electronic systems, in which the interacting electron wavefunctions are those of massless chiral fermions. However, due to the prevailing disorder, graphene has thus far exhibited only weak signatures of correlated electron phenomena, despite concerted experimental efforts and intense theoretical interest. Here, we report the observation of the fractional quantum Hall effect in ultraclean suspended graphene, supporting the existence of strongly correlated electron states in the presence of a magnetic field. In addition, at low carrier density graphene becomes an insulator with an energy gap tunable by magnetic field. These newly discovered quantum states offer the opportunity to study a new state of matter of strongly correlated Dirac fermions in the presence of large magnetic fields

    Using curvature information in haptic shape perception of 3D objects

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    Are humans able to perceive the circularity of a cylinder that is grasped by the hand? This study presents the findings of an experiment in which cylinders with a circular cross-section had to be distinguished from cylinders with an elliptical cross-section. For comparison, the ability to distinguish a square cuboid from a rectangular cuboid was also investigated. Both elliptical and rectangular shapes can be characterized by the aspect ratio, but elliptical shapes also contain curvature information. We found that an elliptical shape with an aspect ratio of only 1.03 could be distinguished from a circular shape both in static and dynamic touch. However, for a rectangular shape, the aspect ratio needed to be about 1.11 for dynamic touch and 1.15 for static touch in order to be discernible from a square shape. We conclude that curvature information can be employed in a reliable and efficient manner in the perception of 3D shapes by touch

    The burden of neglected tropical diseases in Ethiopia, and opportunities for integrated control and elimination

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    Background: Neglected tropical diseases (NTDs) are a group of chronic parasitic diseases and related conditions that are the most common diseases among the 2Β·7 billion people globally living on less than US$2 per day. In response to the growing challenge of NTDs, Ethiopia is preparing to launch a NTD Master Plan. The purpose of this review is to underscore the burden of NTDs in Ethiopia, highlight the state of current interventions, and suggest ways forward. Results: This review indicates that NTDs are significant public health problems in Ethiopia. From the analysis reported here, Ethiopia stands out for having the largest number of NTD cases following Nigeria and the Democratic Republic of Congo. Ethiopia is estimated to have the highest burden of trachoma, podoconiosis and cutaneous leishmaniasis in sub-Saharan Africa (SSA), the second highest burden in terms of ascariasis, leprosy and visceral leishmaniasis, and the third highest burden of hookworm. Infections such as schistosomiasis, trichuriasis, lymphatic filariasis and rabies are also common. A third of Ethiopians are infected with ascariasis, one quarter is infected with trichuriasis and one in eight Ethiopians lives with hookworm or is infected with trachoma. However, despite these high burdens of infection, the control of most NTDs in Ethiopia is in its infancy. In terms of NTD control achievements, Ethiopia reached the leprosy elimination target of 1 case/10,000 population in 1999. No cases of human African trypanosomiasis have been reported since 1984. Guinea worm eradication is in its final phase. The Onchocerciasis Control Program has been making steady progress since 2001. A national blindness survey was conducted in 2006 and the trachoma program has kicked off in some regions. Lymphatic Filariasis, podoconiosis and rabies mapping are underway. Conclusion: Ethiopia bears a significant burden of NTDs compared to other SSA countries. To achieve success in integrated control of NTDs, integrated mapping, rapid scale up of interventions and operational research into co implementation of intervention packages will be crucial

    Regulation of Mycobacterium-Specific Mononuclear Cell Responses by 25-Hydroxyvitamin D3

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    The active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has been shown to be an important regulator of innate and adaptive immune function. In addition, synthesis of 1,25(OH)2D3 from 25-hydroxyvitamin D3 (25(OH)D3) by the enzyme 1Ξ±-hydroxylase in monocytes upon activation by TLR signaling has been found to regulate innate immune responses of monocytes in an intracrine fashion. In this study we wanted to determine what cells expressed 1Ξ±-hydroxylase in stimulated peripheral blood mononuclear cell (PBMC) cultures and if conversion of 25(OH)D3 to 1,25(OH)2D3 in PBMC cultures regulated antigen-specific immune responses. Initially, we found that stimulation of PBMCs from animals vaccinated with Mycobacterium bovis (M. bovis) BCG with purified protein derivative of M. bovis (M. bovis PPD) induced 1Ξ±-hydroxylase gene expression and that treatment with a physiological concentration of 25(OH)D3 down-regulated IFN-Ξ³ and IL-17F gene expression. Next, we stimulated PBMCs from M. bovis BCG-vaccinated and non-vaccinated cattle with M. bovis PPD and sorted them by FACS according to surface markers for monocytes/macrophages (CD14), B cells (IgM), and T cells (CD3). Sorting the PBMCs revealed that 1Ξ±-hydroxylase expression was induced in the monocytes and B cells, but not in the T cells. Furthermore, treatment of stimulated PBMCs with 25(OH)D3 down-regulated antigen-specific IFN-Ξ³ and IL-17F responses in the T cells, even though 1Ξ±-hydroxylase expression was not induced in the T cells. Based on evidence of no T cell 1Ξ±-hydroxylase we hypothesize that activated monocytes and B cells synthesize 1,25(OH)2D3 and that 1,25(OH)2D3 down-regulates antigen-specific expression of IFN-Ξ³ and IL-17F in T cells in a paracrine fashion
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