bluuebunny/crossref_metadata_2025 huggingface dataset:
An XML Gateway to Patient Data for Medical Research Applications
Authors: BUI ALEX A.T. , WEINGER GREGORY S. , BARRETTA SUSAN J. , DIONISIO JOHN DAVID N. , KANGARLOO HOOSHANG
Published: July 2009

Abstract: As the medical environment becomes increasingly electronic, clinical databases are continually growing, accruing masses of patient information. This wealth of data is an invaluable source of information to researchers, serving as a testbed for the development of new information technologies and as a repository of real‐world data for data mining and population‐based studies. However, the true utility of this information is not fulfilled, in part because of issues pertaining to security and patient confidentiality, but also due to the lack of an effective infrastructure to access the data. This paper describes a system, DataServer, that permits researchers to query and retrieve data from multiple clinical data sources, automatically deidentifying patient data so that it can be used for research purposes. DataServer functions as an application framework, enabling extensible markup language (XML)‐based querying of existing medical databases. Key aspects of DataServer include ready inclusion of new information resources, minimal processing impact on existing clinical systems via a distributed cache, and flexible output representation via XSL (eXtensible Style Language) transforms.
Modeling Medical Content for Automated Summarization
Authors: JOHNSON DAVID B. , ZOU QINGHUA , DIONISIO JOHN D. , LIU VICTOR ZHENYU , CHU WESLEY W.
Published: July 2009

Abstract: Medical information is available from a variety of new online resources. Given the number and diversity of sources, methods must be found that will enable users to quickly assimilate and determine the content of a document. Summarization is one such tool that can help users to quickly determine the main points of a document. Previous methods to automatically summarize text documents typically do not attempt to infer or define the content of a document. Rather these systems rely on secondary features or clues that may point to content. This paper describes text summarization techniques that enable users to focus on the key content of a document. The techniques presented here analyze groups of similar documents in order to form a content model. The content model is used to select sentences forming the summary. The technique does not require additional knowledge sources; thus the method should be applicable to any set of text documents.
Structured Reporting in Neuroradiology
Authors: MORIOKA CRAIG A. , SINHA USHA , TAIRA RICKY , EL‐SADEN SUZIE , DUCKWILER GARY , KANGARLOO HOOSHANG
Published: July 2009

Abstract: We have developed a system to structure free‐text neuroradiology reports using a natural language processing program and formatted the output into the digital image and communication in medicine (DICOM) standard for structured reporting (SR). DICOM SR formats the correspondence of pertinent diagnostic images to the radiologist's dictated report of clinical findings. In addition, DICOM SR allows the information to be organized into a tree structure. Individual nodes of the tree can contain individual items or lists. Structuring the content of free‐text information allows the creation of hierarchies with defined relationships between the concepts contained within the report.
Integrated Visualization of Problemcentric Urologic Patient Records
Authors: BUI ALEX A.T. , TAIRA RICKY K. , CHURCHILL BERNARD , KANGARLOO HOOSHANG
Published: July 2009

Abstract: The collision of computer‐based technologies and the medical environment is resulting in an increasingly electronic multimedia patient record, consisting of not only the traditional types of data (e.g., clinic notes and laboratory reports), but also digital images (e.g., computed tomography and magnetic resonance imaging) and other visual representations of patient data (e.g., pulmonary function graphs and urodynamic charts). Given the increasing amount of data made available to physicians, it is not only critical that the totality of a patient's medical record be accessible to a clinician, but that the diverse data be integrated and presented in a manner conducive to patient management: key information should be easily discovered. This paper describes a problemcentric time‐based visualization of urologic conditions, whereby a patient's medical history is automatically organized around a medical problem and presented as a graphic chronology. Urology‐related data in the patient medical record is organized in accord with an expert constructed knowledge‐base, and plotted on a timeline using iconic representations. The user interface permits the physician to quickly view multimedia data and to visualize relationships between events in the patient's history.
The Influence of Gravity on Composition Uniformity and Microstructure in Immiscible Al‐In Alloys
Authors: ANDREWS J. BARRY , HAYES LETITIA J.
Published: July 2009

Abstract: The results obtained from flight experiments on hypermonotectic Al‐In alloys carried out during the Life and Microgravity Spacelab mission are presented and compared to those predicted from models that have been developed for solute redistribution in eutectic alloy systems. Experimental results from microgravity experiments are also compared with results obtained from unit gravity directional solidification experiments. Unit gravity directional solidification of hypermonotectic alloys results in macrosegregation due to convective instability inherent in these alloy systems. Identical samples directionally solidified under microgravity conditions reveal a much more uniform composition profile. Results indicate steady‐state coupled growth is possible in hypermonotectic alloys through microgravity processing.
Thermal Diffusivity Coefficient of Glycerin Determined on an Acoustically Levitated Drop
Authors: OHSAKA K. , REDNIKOV A. , SADHAL S. S.
Published: July 2009

Abstract: We present a technique that can be used to determine the thermal diffusivity coefficient of undercooled liquids that exist at temperatures below their freezing points. The technique involves levitation of a small amount of liquid in the shape of a flattened drop using an acoustic levitator and heating it with a CO2 laser. The heated drop is then allowed to cool naturally by heat loss from the surface. Due to acoustic streaming, heat loss is highly non‐uniform and appears to mainly occur at the drop circumference (equatorial region). This fact allows us to relate the heat loss rate with a heat transfer model to determine the thermal diffusion coefficient. We demonstrate the feasibility of the technique using glycerin drops as a model liquid.
Thermophysical Property Measurements by Electromagnetic Levitation Melting Technique under Microgravity
Authors: BAKHTIYAROV SAYAVUR I. , OVERFELT RUEL A.
Published: July 2009

Abstract: The purpose of this paper is to review the advances in electromagnetic levitation techniques as tools for determination of the thermophysical properties of molten metals under standard gravity and microgravity conditions. We show that a combination of containerless processing and microgravity offers the exclusive possibility to measure critical thermophysical properties of molten metals, both above and below their melting points, over a wide temperature range, and with high accuracy.
Mass and Thermal Diffusivity Algorithms
Authors: BANISH R. MICHAEL , ALBERT LYLE B.J. , POURPOINT TIMOTHEE L. , ALEXANDER J. IWAN D. , SEKERKA ROBERT F.
Published: July 2009

Abstract: Mass and thermal diffusivity measurements conducted on Earth are prone to contamination by uncontrollable convective contributions to the overall transport. Previous studies of mass and thermal diffusivities conducted on spacecraft have demonstration the gain in precision, and lower absolute values, resulting from the reduced convective transport possible in a low‐gravity environment. We have developed and extensively tested real‐time techniques for diffusivity measurements, where several measurements may be obtained on a single sample. This is particularly advantageous for low gravity research were there is limited experiment time. The mass diffusivity methodology uses a cylindrical sample geometry. A radiotracer, initially located at one end of the host is used as the diffusant. The sample is positioned in a concentric isothermal radiation shield with collimation bores located at defined positions along its axis. The intensity of the radiation emitted through the collimators is measured versus time with solid‐state detectors and associated energy discrimination electronics. For the mathematical algorithm that we use, only a single pair of collimation bores and detectors are necessary for single temperature measurements. However, by employing a second, offset, pair of collimation holes and radiation detectors, diffusivities can be determined at several temperatures per sample. For thermal diffusivity measurements a disk geometry is used. A heat pulse is applied in the center of the sample and the temperature response of the sample is measured at several locations. Thus, several values of the diffusivity are measured versus time. The exact analytic solution to a heat pulse in the disk geometry leads to a unique heated area and measurement locations. Knowledge of the starting time and duration of he heating pulse is not used in the data evaluation. Thus, this methodology represents an experimentally simpler and more robust scheme.
Condensate Removal Mechanisms in a Constrained Vapor Bubble Heat Exchanger
Authors: ZHENG LING , WANG YINGXIN , WAYNER PETER C. , PLAWSKY JOEL L.
Published: July 2009

Abstract: Microgravity experiments on the constrained vapor bubble heat exchanger (CVB) are being developed for the space station. Herein, ground‐based experimental studies on condensate removal in the condenser region of the vertical CVB were conducted and the mechanism of condensate removal in microgravity was found to be the capillary force. The effects of curvature and contact angle on the driving forces for condensate removal is studied. The Nusselt correlations are derived for the film condensation and the flow from the drop to the meniscus at the moment of merging. These new correlations scale as forced convection with h∝L1/2 or h∝L1/2cd. For the partially wetting ethanol system studied, the heat transfer coefficient for film condensation was found to be 4.25 × 104 W/m2K; for dropwise condensation at moment of merging it was found to be 9.64 × 104 W/m2K; and for single drops it was found to be 1.33 × 105 W/m2K.
Vapor Bubbles in Flow and Acoustic Fields
Authors: PROSPERETTI ANDREA , HAO YUE
Published: July 2009

Abstract: A review of several aspects of the interaction of bubbles with acoustic and flow fields is presented. The focus of the paper is on bubbles in hot liquids, in which the bubble contains mostly vapor, with little or no permanent gas. The topics covered include the effect of translation on condensation in a subcooled liquid, the action of pressure gradients on bubbles convected by a liquid flow, rectified heat diffusion on stationary and moving bubbles, the effect of permanent gas on this phenomenon, and the action of pressure‐radiation (or Bjerknes) forces.
Rapidly Expanding Viscous Drop from a Submerged Orifice at Finite Reynolds Numbers
Authors: GUPTA NIVEDITA R. , BALASUBRAMANIAM R. , STEBE KATHLEEN J.
Published: July 2009

Abstract: The rapid expansion and subsequent detachment of a drop or bubble are examined in this paper. Establishing the hydrodynamics of the drop growth and detachment process has applications ranging from improving insight into nucleate pool boiling, to improving techniques used to characterize dynamic surface tension. Here, the growth and detachment dynamics of vis‐cous drops are studied numerically to establish an accurate description of the hydrodynamics. The full two‐dimensional axisymmetric Navier‐Stokes equations are solved using a single fluid volume‐of‐fluid (VOF) formulation on a fixed Eulerian grid. The interface is represented by marker particles that are convected in a Lagrangian manner on the underlying Eulerian grid. Results for surfactant‐free, isothermal droplets from hemispherical caps to near detachment are presented.
Pool Film Boiling Experiments on a Wire in Low Gravity
Authors: DI MARCO P. , GRASSI W. , TRENTAVIZI F.
Published: July 2009

Abstract: This paper reports preliminary results for pool film boiling on a wire immersed in almost saturated FC72 recently obtained during an experimental campaign performed in low gravity on the European Space Agency Zero‐G airplane, (reduced gravity level 10−2). This is part of a long‐term research program on the effect of gravitational and electric forces on boiling. The reported data set refers to experiments performed under the following conditions: (1) Earth gravity without electric field, (2) Earth gravity with electric field, (3) low gravity without electric field, and (4) low gravity with electric field. Although a decrease of gravity causes a heat transfer degradation, the electric field markedly improves heat exchange. This improvement is so effective that, beyond a certain field value, the heat flux is no longer sensitive to gravity. Two main film boiling regimes have been identified, both in normal and in low gravity: one is affected by the electric field and the other is practically insensitive to the field influence.
Flow Field Measurements in the Cell Culture Unit
Authors: WALKER STEPHEN , WILDER MIKE , DIMANLIG ARSENIO , JAGGER JUSTIN , SEARBY NANCY
Published: July 2009

Abstract: The cell culture unit (CCU) is being designed to support cell growth for long‐duration life science experiments on the International Space Station (ISS). The CCU is a perfused loop system that provides a fluid environment for controlled cell growth experiments within cell specimen chambers (CSCs), and is intended to accommodate diverse cell specimen types. Many of the functional requirements depend on the fluid flow field within the CSC (e.g., feeding and gas management). A design goal of the CCU is to match, within experimental limits, all environmental conditions, other than the effects of gravity on the cells, whether the hardware is in microgravity (μg), normal Earth gravity, or up to 2g on the ISS centrifuge. In order to achieve this goal, two steps are being taken. The first step is to characterize the environmental conditions of current 1g cell biology experiments being performed in laboratories using ground‐based hardware. The second step is to ensure that the design of the CCU allows the fluid flow conditions found in 1g to be replicated from microgravity up to 2g. The techniques that are being used to take these steps include flow visualization, particle image velocimetry (PIV), and computational fluid dynamics (CFD). Flow visualization using the injection of dye has been used to gain a global perspective of the characteristics of the CSC flow field. To characterize laboratory cell culture conditions, PIV is being used to determine the flow field parameters of cell suspension cultures grown in Erlenmeyer flasks on orbital shakers. These measured parameters will be compared to PIV measurements in the CSCs to ensure that the flow field that cells encounter in CSCs is within the bounds determined for typical laboratory experiments. Using CFD, a detailed simulation is being developed to predict the flow field within the CSC for a wide variety of flow conditions, including microgravity environments. Results from all these measurements and analyses of the CSC flow environment are presented and discussed. The final configuration of the CSC employs magnetic stir bars with angled paddles to achieve the necessary flow requirements within the CSC.
Compact Optical Sensor for Real‐Time Monitoring of Bacterial Growth for Space Applications
Authors: VAN BENTHEM R. C. , VAN DEN ASSEM D. , KROONEMAN J.
Published: July 2009

Abstract: During long‐duration manned space missions, complex chemical and biological processes need to be managed accurately for recycling human wastes and to produce human consumables. As a result, there is increasing interest in how the characteristics of microbes are influenced by microgravity. Compact optical instrumentation allows for real‐time and non‐invasive measurement of bacterial growth parameters during flight experiments. In close collaboration, the National Aerospace Laboratory of the Netherlands (NLR) and Bioclear Environmental Biotechnology developed and tested an on‐line optical biomass sensor successfully. The sensor concept is based on a turbidity measurement technique operating in the VIS‐blue part of the light spectrum with use of blue LED sources. A diagnostic tool has been developed using com‐pact spectrometers and optical fibers to characterize bacterial cultures. As a result a few sensor applications operating at different colors and sensor layouts are discussed in the paper.
Molecular Characterization of Antigen‐Induced Lung Inflammation in a Murine Model of Asthma
Authors: DAHESHIA MASSOUD , TIAN NIAN , CONNOLLY TIMOTHY , DRAWID AMAR , WU QUIYAN , BIENVENU JEAN‐GUY , CAVALLO JEAN , JUPP RAY , DE SANCTIS GEORGE T. , MINNICH ANNE
Published: July 2009

Abstract: Asthma is one of the foremost contributors to morbidity and mortality in industrialized countries. Our objective was to characterize the acute response to allergen and to identify potentially novel molecular targets for pharmacological intervention in asthma. We therefore designed a study to identify genes whose regulation was altered following ovalbumin (OVA) challenge in the presence and absence of treatment with glucocorticoids in BALB/c mice. RNA was isolated from lungs for gene profiling from 8‐week‐old sensitized mice, 3 and 18 hours post OVA challenge on days 1, 4, and 7 of aerosol challenge. Taqman (real time RT‐PCR) analysis of marker genes indicative of Th2 (IL‐4, IL‐13), eosinophil (RANTES, eotaxin), Th1/macrophage (IFNγ) and epithelial cell (MUC5AC) phenotypes were used to characterize responses to allergen challenge. Histological evaluation of lungs from additional challenged animals revealed inflammatory infiltrates on days 4 and 7, but not on day 1 post challenge. We postulate that expression of IL‐4, IL‐13 and other genes by OVA at day 1 probably reflects activation of resident cells, whereas the fivefold increase in the number of regulated genes at day 7 reflects the contribution of recruited cells. Of the regulated genes, only a subset was counter‐regulated by dexamethasone treatment. Although regulated genes included genes in many protein families, herein we report regulation of two proteases whose role in response to OVA challenge has not been characterized. This model will be used to generate disease hypotheses for which may play an important role in initiating disease pathology in this model.
Activation of Complement in the Central Nervous System
Authors: Van BEEK JOHAN , ELWARD KRISTINA , GASQUE PHILIPPE
Published: July 2009

Abstract: The complement system is an essential effector of the humoral and cellular immunity involved in cytolysis and immune/inflammatory responses. Complement participates in host defense against pathogens by triggering the formation of the membrane attack complex. Complement opsonins (C1q, C3b, and iC3b) interact with surface complement receptors to promote phagocytosis, whereas complement anaphylatoxins C3a and C5a initiate local inflammatory responses that ultimately contribute to the protection and healing of the host. However, activation of complement to an inappropriate extent has been proposed to promote tissue injury. There is now compelling evidence that complement activation in the brain is a double‐edged sword in that it can exert beneficial or detrimental effects depending on the pathophysiological context. This review focuses on the roles of the complement system in the pathogenesis of acute brain injury (cerebral ischemia and trauma) and chronic neurodegeneration (Alzheimer's disease). Because many effects of the complement appear to promote neuronal survival and tissue remodeling, directing activation of the complement system in the brain may provide a better therapeutic rationale than inhibiting it.
Effect of Neurogenic Stress and Ethanol on Nitric Oxide Synthase and Cyclooxygenase Activities in Rat Adrenals
Authors: RETTORI VALERIA , MOHN CLAUDIA , SCORTICATI CAMILA , VISSIO PAULA , CELLA MAXIMILIANO , FARINA MARIANA , FRANCHI ANA , MCCANN SAMUEL M.
Published: July 2009

Abstract: Repeated restraint stress (RRS) in male rats activated the pituitary adrenal system, as indicated by increases in adrenal weight and plasma corticosterone concentration that were accompanied by a decrease in constitutive nitric oxide synthase (cNOS), but not inducible NOS (iNOS). iNOS activated cyclooxgenase, causing elevated prostaglandin E2 (PGE2) and F2α in the adrenals, but had no effect on lipoxygenase. Administration of ethanol (ETOH) was also associated with elevated adrenal weight and a slight increase in corticosterone coupled with a decrease in both cNOS and iNOS and PGs in the adrenal. When ETOH was administered together with RRS, a decrease in iNOS and PGE release was noted consequent to a reduction in iNOS. Thus, ETOH probably reduced RRS‐induced adrenocorticotropic hormone release. Adrenals were incubated in vitro to further evaluate the role of NO in these processes. Results indicated that NO released by sodium nitroprusside increased corticosterone release presumably by activating guanylyl cyclase with production of cyclic guanosine monophosphate (cGMP), because although NO also increased PGE release, PGE2 (10−5‐10−9 M) decreased corticosterone release, an effect that was highly significant at a concentration of 10−7 M PGE2. ETOH (100 mM) had no effect on corticosterone release and did not block the increase in corticosterone caused by NO; however, ETOH reduced PGE release into the medium and blocked PGE2 release induced by NO. Consequently, NO activated corticosterone release not by PGs, but by activation of guanylyl cyclase and release of cGMP. PGs have a negative feedback to suppress corticosterone release.
Hypothalamo‐Pituitary‐Adrenal Axis and Chronic Immune Activation
Authors: HARBUZ MICHAEL S. , CHOVER‐GONZALEZ ANJO J. , JESSOP DAVID S.
Published: July 2009

Abstract: Corticosteroids have potent immunosuppressive and anti‐inflammatory effects. Although corticosteroids are an important weapon in the clinical arsenal for treating inflammatory episodes, the mechanisms underlying the actions and regulation of endogenous corticosteroids remain obscure. In the late 1980s and early 1990s, a hypothesis was proposed that suggested that susceptibility to autoimmune disease was linked to a hypoactive hypothalamo‐pituitary‐adrenal (HPA) axis. It was further suggested that this defect in regulation of the HPA axis was situated at the level of the hypothalamus. This compelling hypothesis directly linked control of the HPA axis with susceptibility to disease rather than just severity of inflammation. The initial findings acted as a stimulus to further research, and over the next decade the hypothesis was tested. Recent studies suggest that the original hypothesis is in need of modification and that susceptibility is more complex and requires the involvement of more than a single parameter. These data are discussed together with recent developments concerning regulation of the HPA in disease in preclinical models and patients with rheumatoid arthritis. The latter studies in patients with rheumatoid arthritis provide evidence for the existence of a subpopulation of these patients with altered negative feedback regulation of the HPA axis.
In Vivo Effects of Growth Hormone on Thymic Cells
Authors: SAVINO WILSON , SMANIOTTO SALETE , BINART NADINE , POSTEL‐VINAY MARIE CATHERINE , DARDENNE MIREILLE
Published: July 2009

Abstract: Increasing evidence has placed the thymus as a target for neuroendocrine control. Herein we review the pleiotropic effects of growth hormone (GH) on this primary lymphoid organ, with emphasis on data derived from in vivo experiments. A series of results strongly indicate that GH enhances thymocyte proliferation in both rodents and humans. Moreover, in vivo treatment with GH enhances interleukin (IL)‐6 production by mouse thymocytes, and ex vivo experiments show that production of other cytokines, such as IL‐1 and GM‐CSF, is also augmented. In a second vein, GH exerts a modulatory role on thymic hormone production, particularly the secretion of thymulin. In GH‐treated animals as well as GH‐transgenic mice, thymulin secretion is enhanced. In acromegalic patients we found higher levels of thymulin secretion, whereas the opposite was seen in dwarf mice and GH receptor knockout animals. Developing T cell migration is also under GH influence. Recombinant GH was found to increase human T cell engraftment in the thymus of SCID mice. Moreover, ex vivo thymocyte traffic into and out of thymic nurse cell complexes is enhanced after GH treatment. Lastly, we show that thymocyte export in vivo is modulated by GH, which favors the homing of CD4+ recent thymic emigrants towards lymph nodes. In conclusion, the possibility that GH improves in vivo thymic functions, including thymocyte proliferation and migration, points to this molecule as a potential therapeutic adjuvant in T cell associated immunodeficiencies.
Role of the Thymus in the Development of Tolerance and Autoimmunity towards the Neuroendocrine System
Authors: GEENEN VINCENT , BRILOT FABIENNE
Published: July 2009

Abstract: The thymus is the unique lymphoid organ inside which a confrontation occurs throughout life between neuroendocrine self‐antigens and a recently evolved system with original recombination machinery driving random generation of immune response diversity. Through transcription of neuroendocrine genes in the thymus stromal network and expression of cognate receptors by immature T cells, the neuroendocrine system regulates early T cell differentiation. In addition and more specifically, intrathymic presentation of neuroendocrine self‐antigens by, or in close association with, major histocompatibility complex (MHC) proteins is responsible for the establishment of central immune self‐tolerance of neuroendocrine principles. All members of the insulin gene (INS) family are expressed in the thymus stroma according to a precise hierarchy and cell topography: IGF2 (thymic epithelial cells) > IGF1 (thymic macrophages) ≫INS (thymic medullary epithelial cells and/or dendritic cells). Given this hierarchical pattern in gene expression, the protein IGF‐2 is more tolerated than INS. Igf2 transcription is defective in the thymus of bio‐breeding (BB) rat, one animal model of type 1 diabetes (T1DM). This thymus‐specific defect in Igf2 expression may explain both the absence of central tolerance to INS‐secreting β cells and the lymphopenia (including lack of regulatory RT6+ T cells) in diabetes‐prone BB rats. INS B:9–23 and the homologous sequence of IGF‐2 compete for binding to DQ8, an MHC class II allele conferring major susceptibility to T1DM. In young DQ8+ T1DM patients, INS B:9–23 presentation by DQ8 elicits a dominant IFN‐γ secretion by isolated PBMCs, whereas presentation of the IGF‐2 self‐antigen promotes a dominant regulatory interleukin‐10 secretion. These data demonstrate that opposite immune responses are driven by MHC presentation of a self‐antigen (here, IGF‐2) and an autoantigen (INS, as “altered” self). The important tolerogenic properties of thymic self‐antigens deserve now to be exploited for prevention and/or cure of devastating autoimmune diseases such as T1DM.
Endocrine and Immune Responses to Stress in Chronic Inflammatory Skin Disorders
Authors: BUSKE‐KIRSCHBAUM ANGELIKA , HELLHAMMER DIRK H.
Published: July 2009

Abstract: Atopy is a genetically and environmentally determined condition predisposing to different forms such as atopic dermatitis (AD) or allergic asthma (AA). Both AD and AA are considered to be multifactorial diseases; however, distinct immunologic abnormalities have been described that play a crucial role. There is growing evidence that immunoglobulin‐E hypersecretion and activation of the predominantly T‐helper‐2 (TH2)‐like T cell subset trigger allergic inflammatory processes and cause the disease to become chronic. In the present paper, data suggesting reduced hypothalamic‐pituitary‐adrenal (HPA) axis responsiveness in patients with AD and AA are summarized, and the potential etiologic significance of a hyporeactive HPA axis is discussed. We propose that because of defective HPA axis, immunoregulation under stressful conditions is ineffective in patients with atopic conditions, leading to aberrant immune responses and subsequent exacerbation of the disease. Further research into the role of the HPA axis in atopy may elucidate the cause of stress‐induced exacerbation of atopic symptoms and may be of clinical relevance.
Loops and Links: Structural Insights into the Remarkable Function of the Agouti‐Related Protein
Authors: MILLHAUSER GLENN L. , McNULTY JOE C. , JACKSON PILGRIM J. , THOMPSON DARREN A. , BARSH GREGORY S. , GANTZ IRA
Published: July 2009

Abstract: The agouti‐related protein (AGRP) is an endogenous antagonist of the melanocortin receptors MC3R and MC4R found in the hypothalamus and exhibits potent orexigenic activity. The cysteine‐rich C‐terminal domain of this protein, corresponding to AGRP(87–132), exhibits receptor binding affinity and antagonism equivalent to that of the full‐length protein. We recently determined the NMR structure of AGRP(87–132) and demonstrated that a portion of the domain adopts the inhibitor cystine‐knot fold. Remarkably, this is the first identification of a mammalian protein with this specific architecture. Further analysis of the structure suggests that melanocortin receptor contacts are made primarily by two loops presented within the cystine knot.10 To test this hypothesis we designed a 34‐residue AGRP analogue corresponding to only the cystine knot. We found that this designed miniprotein folds to a homogeneous product, retains the desired cystine‐knot architecture, functions as a potent antagonist, and maintains the melanocortin receptor pharmacological profile of AGRP(87–132).26 The AGRP‐like activity of this molecule supports the hypothesis that indeed the cystine‐knot region possesses the melanocortin receptor contacts. Based on these design and structure studies, we propose that the N‐terminal loop of AGRP(87–132) makes contact with a receptor exoloop and helps confer AGRP's selectivity for the central MCRs.
Molecular Genetics of Human Obesity‐Associated MC4R Mutations
Authors: LUBRANO‐BERTHELIER CECILE , CAVAZOS MARTHA , DUBERN BEATRICE , SHAPIRO ASTRID , LE STUNFF CATHERINE , ZHANG SUMEI , PICART FRANCK , GOVAERTS CEDRIC , FROGUEL PHILIPPE , BOUGNÈRES PIERRE , CLEMENT KARINE , VAISSE CHRISTIAN
Published: July 2009

Abstract: Heterozygous coding mutations in the melanocortin 4 receptor (MC4R) are implicated in 1 to 6% of early onset or severe adult obesity cases. To better address the problem of the genotype:phenotype relationship within this specific form of obesity, we systematically studied the functional characteristics of 50 different obesity‐associated MC4R mutations. Structure modeling of MC4R indicates that obesity‐associated MC4R mutations are not localized in a single domain of the protein. We developed a flow cytometry‐based assay to compare cell membrane expression of obesity‐associated MC4R mutants. Using this assay, we demonstrate that over 54% of the obesity‐associated MC4R mutations impair the membrane expression of MC4R. All other mutations impair the basal constitutive activity and/or the EC50 for the physiological agonist α‐MSH as measured in a cAMP‐ dependent luciferase assay. The extent of the alterations in receptor activity ranges from a total suppression of MC4R activation in response to α‐MSH to a mild alteration of the basal constitutive activity of the receptor. Since most patients are heterozygous for MC4R mutations, these data indicate that a small decrease in overall MC4R activity can cause obesity, strongly supporting the hypothesis that the MC4R is a critical component of the adipostat in humans.
γ‐MSH Peptides in the Pituitary
Authors: DENEF C. , LU J. , SWINNEN E.
Published: July 2009

Abstract: The melanocortin (MC) γ3‐MSH is believed to signal through the MC3 receptor. We showed that it induces a sustained increase in intracellular free calcium levels ([Ca2+]i) in a subpopulation of pituitary cells. Most of the cells responding to γ3‐MSH express more than one pituitary hormone mRNA. The effect of γ3‐MSH is blocked by SHU9119, a MC3R and MC4R antagonist, in only 50% of the responsive cells, suggesting that in half of these cells the mediating receptor is not the MC3R. Low picomolar doses of γ3‐MSH increase [Ca2+]i in the growth hormone (GH)‐ and prolactin (PRL)‐secreting GH3 cell line. γ2‐MSH and α‐MSH display a similar effect. SHU9119 does not affect the γ3‐MSH‐induced [Ca2+]i response. MTII, a potent synthetic agonist of the MC3R, MC4R, and MC5R, also shows no or low potency in increasing [Ca2+]i. By means of RT‐PCR, the mRNA of the MC2R, MC3R, and MC4R receptors is undetectable. Experiments testing γ2‐MSH analogues with single alanine replacements show that, unlike the classic MCRs, the His5‐Phe6‐Arg7‐Trp8 sequence in γ2‐MSH is not a core sequence for activating the γ‐MSH receptor in GH3 cells, whereas Met3 is essential. Low nanomolar doses of γ‐MSH increase intracellular cAMP levels. Blockade of protein kinase A abolishes the [Ca2+]i responses to γ3‐MSH. γ2‐MSH increases binding of [S35]GTPγS to membrane preparations of GH3 cells. The pharmacological characteristics of γ‐MSH peptides and analogues on [Ca2+]i and the signal‐transduction pathways present strong evidence for the expression of a hitherto uncharacterized γ‐MSH receptor in GH3 cells, belonging to the G protein‐coupled receptor family.
Mutations in the Human Proopiomelanocortin Gene
Authors: KRUDE HEIKO , BIEBERMANN HEIKE , GRÜTERS ANNETTE
Published: July 2009

Abstract: The melanocortin peptides and their receptors represent one of the most complex systems in human endocrinology. Hormonal regulation includes pigmentation, weight maintenance, adrenal function, and exocrine gland secretion via endocrine, paracrine, autocrine, and neurocrine action of melanocortin peptides at five different but homologous melanocortin receptors. Genetic relevance of the melanocortin system for human physiology was initially shown by mutations in the different melanocortin receptor genes, first described in the melanocortin‐2 receptor gene in 1993 as one reason for congenital hypocortisolism. Because all ligands within the melanocortin systems are derived from one single precursor hormone, proopiomelanocortin (POMC), a genetic defect in the POMC gene could have been expected to affect all functional components of the melanocortin system. Accordingly, patients with a complete defect of the POMC gene product due to homozygous or compound heterozygous loss of function mutations were shown to be affected mainly by red hair, early‐onset obesity, and congenital hypocortisolism. No further obvious clinical problems were described in these patients, suggesting that no additional function of the melanocortin system has escaped recognition. However, whether partial loss of function mutations in the POMC gene might lead to more circumscribed phenotypes, especially common obesity, remains an open question.
The Role of the Melanocortin‐3 Receptor in Cachexia
Authors: MARKS DANIEL L. , CONE ROGER D.
Published: July 2009

Abstract: Cachexia refers to a synergistic combination of a dramatic decrease in appetite and an increase in metabolism of fat and lean body mass. This combination is found in a number of chronic diseases and is an important determinant of mortality. In this paper, we provide evidence that in both acute and chronic disease models, blockade of the MC4‐R results in a dramatic attenuation of cachexia. We have also demonstrated that blockade of the melanocortin‐3 receptor (MC3‐R) leads to enhanced disease‐associated cachexia. Ultimately, this work may lead to investigation of drug therapy for this widespread medical problem.
Melanocortin System and Eating Disorders
Authors: ADAN ROGER A.H. , HILLEBRAND JACQUELIEN J.G. , De RIJKE CORINE , NIJENHUIS WOUTER , VINK TOM , GARNER KEITH M. , KAS MARTIEN J.H.
Published: July 2009

Abstract: The melanocortin (MC) system is involved in the regulation of energy balance and in the development of obesity. Here we briefly review why we became interested in investigating whether the MC system — more particularly, the increased activity of the MC system — is also involved in disorders of negative energy balance. We provide evidence that suppression of increased MC receptor activity by treatment with the inverse agonist agouti‐related peptide (AgRP) (83–132) rescues rats exposed to an animal model known as activity‐based anorexia. Furthermore, we found a polymorphism, Ala67Thr AgRP, that was observed more frequently in anorexia nervosa.
Melanocortin Signaling and Anorexia in Chronic Disease States
Authors: WISSE BRENT E. , SCHWARTZ MICHAEL W. , CUMMINGS DAVID E.
Published: July 2009

Abstract: Data from both rodent models and humans suggest that intact neuronal melanocortin signaling is essential to prevent obesity, as mutations that decrease the melanocortin signal within the brain induce hyperphagia and excess body fat accumulation. Melanocortins are also involved in the pathogenesis of disorders at the opposite end of the spectrum of energy homeostasis, the anorexia and weight loss associated with inflammatory and neoplastic disease processes. Studies using melanocortin antagonists (SHU9119 or agouti‐related peptide) or genetic approaches (melanocortin‐4 receptor null mice) suggest that intact melanocortin tone is required for anorexia and weight loss induced by injected lipopolysaccharide (an inflammatory gram‐negative bacterial cell wall product) or by implantation of prostate or lung cancer cells. Although the precise mechanism whereby peripheral inflammatory/neoplastic factors activate the melanocortin system remains unknown, the proinflammatory cytokines (interleukin‐1, interleukin‐6, and tumor necrosis factor‐α) that are produced in the hypothalamus of rodents during both inflammatory and neoplastic disease processes likely play a role. The data presented in this paper summarize findings that implicate neuronal melanocortin signaling in inflammatory anorexia.
Melanocortin Receptor Variants with Phenotypic Effects in Horse, Pig, and Chicken
Authors: ANDERSSON LEIF
Published: July 2009

Abstract: The melanocortin system is of considerable interest in domestic animals because their energy metabolism and pigmentation have been under strong selection. This article reviews our work on MC1R variants in horse, pig, and chicken, as well as a study on MC4R polymorphism in the pig. The chestnut coat color in horses is caused by an MC1R missense mutation (S83F). In the pig, we have described seven MC1R alleles controlling four different coat color phenotypes (wild type, dominant black, black spotting, and recessive red). The most interesting allele is the one causing black spotting because it carries two causative mutations, a frameshift and a missense mutation. The frameshift mutation is somatically unstable, and the black spots reflect somatic reversion events restoring the reading frame. Classic genetics have established eight alleles at the Extended black locus in chicken, which is assumed to correspond to the Extension locus in mammals. We have analyzed the co‐segregation of alleles at MC1R and Extended black using a red jungle fowl × White Leghorn intercross and provide compelling evidence that these loci are identical. A previous study indicated that a missense mutation (D298N) in pig MC4R has an effect on fatness, growth, and feed intake. We could not confirm this association using an intercross between the wild boar and Large White domestic pigs, but it is possible that our F2 generation was too small to detect the rather modest effect reported for this polymorphism.
Defining the Quantitative Contribution of the Melanocortin 1 Receptor (MC1R) to Variation in Pigmentary Phenotype
Authors: HA T. , NAYSMITH L. , WATERSTON K. , OH C. , WELLER R. , REES J. L.
Published: July 2009

Abstract: The melanocortin 1 receptor (MC1R) is a key determinant of pigmentary phenotype. Several sequence variants of the MC1R have been described, many of which are associated with red hair and cutaneous sensitivity to ultraviolet radiation even in the absence of red hair. Red hair approximates to an autosomal recessive trait, and most people with red hair are compound heterozygote or homozygous for limited numbers of mutations that show impaired function in in vitro assays. There is a clear heterozygote effect on sun sensitivity (even in those without red hair) and with susceptibility to the most common forms of skin cancer.
Genetic Association and Cellular Function of MC1R Variant Alleles in Human Pigmentation
Authors: STURM R. A. , DUFFY D. L. , BOX N. F. , NEWTON R. A. , SHEPHERD A. G. , CHEN W. , MARKS L. H. , LEONARD J. H. , MARTIN N. G.
Published: July 2009

Abstract: We have examined MC1R variant allele frequencies in the general population of South East Queensland and in a collection of adolescent dizygotic and monozygotic twins and family members to define statistical associations with hair and skin color, freckling, and mole count. Results of these studies are consistent with a linear recessive allelic model with multiplicative penetrance in the inheritance of red hair. Four alleles, D84E, R151C, R160W, and D294H, are strongly associated with red hair and fair skin with multinomial regression analysis showing odds ratios of 63, 118, 50, and 94, respectively. An additional three low‐penetrance alleles V60L, V92M, and R163Q have odds ratios 6, 5, and 2 relative to the wild‐type allele. To address the cellular effects of MC1R variant alleles in signal transduction, we expressed these receptors in permanently transfected HEK293 cells. Measurement of receptor activity via induction of a cAMP‐responsive luciferase reporter gene found that the R151C and R160W receptors were active in the presence of NDP‐MSH ligand, but at much reduced levels compared with that seen with the wild‐type receptor. The ability to stimulate phosphorylation of the cAMP response element binding protein (CREB) transcription factor was also apparent in all stimulated MC1R variant allele‐expressing HEK293 cell extracts as assessed by immunoblotting. In contrast, human melanoma cell lines showed wide variation in the their ability to undergo cAMP‐mediated CREB phosphorylation. Culture of human melanocytes of known MC1R genotype may provide the best experimental approach to examine the functional consequences for each MC1R variant allele. With this objective, we have established more than 300 melanocyte cell strains of defined MC1R genotype.
TIAF1 Participates in the Transforming Growth Factor β1‐Mediated Growth Regulation
Authors: KHERA SMAIRA , CHANG NAN‐SHAN
Published: July 2009

Abstract: TGF‐β induces growth suppression and apoptosis of various types of cells, but supports fibroblast growth. We previously isolated TIAF1 (TGF‐β1‐induced antiapoptotic factor 1), which protects murine L929 fibroblasts from TNF cytotoxicity. Here, we show that TIAF1 induced growth inhibition and apoptosis of monocytic U937 and other types of cells. In contrast, like TGF‐β1, TIAF1 supported transforming growth of L929 fibroblasts. TIAF1 increased the expression of p53, Cip1/p21, and Smad proteins; suppressed ERK phosphorylation; and altered TGF‐β1‐mediated Smad2/3 phosphorylation in U937 cells. Antisense TIAF1 mRNA significantly enhanced the proliferation of mink lung Mv1Lu epithelial cells. Together, these observations indicate that TIAF1 participates in the TGF‐β‐mediated growth regulation.
Characterization and Expression of Novel 60‐kDa and 110‐kDa EGFR Isoforms in Human Placenta
Authors: REITER JILL L. , MAIHLE NITA J.
Published: July 2009

Abstract: The epidermal growth factor receptor (EGFR) and related family members (ERBB2, ERBB3, and ERBB4) previously have been shown to play pivotal roles in the development of female reproductive tissues, in blastocyst implantation, and in placental differentiation. We have cloned and sequenced several naturally occurring alternative transcripts of the human and mouse EGFR genes, which encode novel receptor isoforms containing varying portions of the extracellular ligand‐binding domain, but lacking the transmembrane and cytoplasmic domain sequences. The human 1.8‐kb and 3‐kb alternative EGFR transcripts encode secreted 60‐kDa and cell surface‐associated 110‐kDa EGFR isoforms, respectively. We have developed quantitative ribonuclease protection assays to study the expression of these alternative transcripts in human tissues. Similar to the full‐length EGFR mRNAs, the highest expression level of these alternative transcripts occurs in placenta. We speculate that both of these EGFR isoforms may be important regulators of EGF‐mediated cell growth and differentiation in human placenta.
Genetic and Epigenetic Mosaicism in Cancer Precursor Tissues
Authors: TYCKO BENJAMIN
Published: July 2009

Abstract: The concept of field effects in cancer is old, but recent molecular data have substantiated it. Clones of cells that carry well‐defined genetic or epigenetic aberrations, but which have not yet acquired the morphological hallmarks of neoplasia, have been documented in the precursor tissues of some of the most common pediatric and adult malignancies. Here I review this evidence, focusing on loss of heterozygosity (LOH) and gain of DNA methylation.
The Development of CpG Island Methylation Biomarkers Using Restriction Landmark Genomic Scanning
Authors: SMIRAGLIA DOMINIC J. , PLASS CHRISTOPH
Published: July 2009

Abstract: CpG island hypermethylation is a common occurrence in cancer. Because this is a stable molecular alteration of the DNA, which can be detected easily from very small amounts, DNA methylation is an attractive candidate to use as a molecular biomarker. Recent studies have used DNA methylation of genes known to be targets of genetic disruption in cancer as biomarkers for early detection of cancer, classification of malignancies, response to drug treatment, and as markers predictive of outcome. Since many of the currently used targets of methylation are methylated at rather low frequencies in various cancer types even though the gene may be frequently disrupted by other mechanisms, it would be useful to develop additional markers that are methylated at high frequency in the cancer being studied. Restriction landmark genomic scanning has been used for the identification of frequent targets of methylation in multiple malignancies. These markers, which can be either cancer type‐specific or nonspecific, may prove to be effective biomarkers for diagnostic or prognostic purposes, or for midpoint analysis of intervention strategies.