4,758 research outputs found

    Early responses to chemotherapy detected by pulse cytophotometry.

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    DNA/cell distributions were recorded by automated cytofluorometry (=pulse cytophotometry) in bone-marrow aspirates of leukaemia and lymphosarcoma patients subjected to chemotherapy. In most cases, early perturbations in DNA/cell histographs were observed, characteristically reflecting the known mode of action of the drugs. These changes in general preceded the clinical observation of drug response. In a series of 23 measurements in 19 patients, a positive correlation between early cytophotometric changes and clinical effects of chemotherapy was observed in 17 patients. Five patients were negative for both cytophotometric and clinical reactions and one patient was probably false-positive. The validity of the assay for early detection of drug resistance in acute leukaemia and related diseases is discussed

    Evaluation par test simplifié in vivo de la chimiosensibilité du Plasmodium falciparum à la chloroquine et à l'amodiaquine dans le Sud du Cameroun

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    La sensibilité in vivo du #Plasmodium falciparumaˋlachloroquineetaˋl′amodiaquineaˋladosede25mg/kgperosentroisjoursaeˊteˊeˊvalueˊeparsixenque^teseffectueˊesen1989dansleSud−OuestduCameroun.Lapreˊvalenceplasmodialechezleseˊcoliersestde75 à la chloroquine et à l'amodiaquine à la dose de 25 mg/kg per os en trois jours a été évaluée par six enquêtes effectuées en 1989 dans le Sud-Ouest du Cameroun. La prévalence plasmodiale chez les écoliers est de 75 %. #Plasmodium falciparum est présent dans 96 % des infections. Parmi 357 enfants traités à la chloroquine, 24 % sont porteurs de trophozoïtes au 3ème jour du traitement et 17 % au 7ème jour. Une résistance complète de type R III est observée dans 4 % des cas. Parmi les 55 enfants traités à l'amodiaquine, 13 % et 10 % sont trouvés porteurs de rares trophozoïtes à J3 ET J7. La signification de ces résultats est discutée. (Résumé d'auteur

    Magnetic-film atom chip with 10 μ\mum period lattices of microtraps for quantum information science with Rydberg atoms

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    We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 μ\mum, suitable for experiments in quantum information science employing the interaction between atoms in highly-excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cut out of a silver foil, was mounted under the atom chip in order to load ultracold 87^{87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.Comment: 7 pages, 7 figure

    Ultraviolet Signposts of Resonant Dynamics in the Starburst-Ringed Sab Galaxy, M94 (NGC 4736)

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    M94 (NGC 4736) is investigated using images from the Ultraviolet Imaging Telescope (FUV-band), Hubble Space Telescope (NUV-band), Kitt Peak 0.9-m telescope (H-alpha, R, and I bands), and Palomar 5-m telescope (B-band), along with spectra from the International Ultraviolet Explorer and Lick 1-m telescopes. The wide-field UIT image shows FUV emission from (a) an elongated nucleus, (b) a diffuse inner disk, where H-alpha is observed in absorption, (c) a bright inner ring of H II regions at the perimeter of the inner disk (R = 48 arcsec. = 1.1 kpc), and (d) two 500-pc size knots of hot stars exterior to the ring on diametrically opposite sides of the nucleus (R= 130 arcsec. = 2.9 kpc). The HST/FOC image resolves the NUV emission from the nuclear region into a bright core and a faint 20 arcsec. long ``mini-bar'' at a position angle of 30 deg. Optical and IUE spectroscopy of the nucleus and diffuse inner disk indicates an approximately 10^7 or 10^8 yr-old stellar population from low-level starbirth activity blended with some LINER activity. Analysis of the H-alpha, FUV, NUV, B, R, and I-band emission along with other observed tracers of stars and gas in M94 indicates that most of the star formation is being orchestrated via ring-bar dynamics involving the nuclear mini-bar, inner ring, oval disk, and outer ring. The inner starburst ring and bi-symmetric knots at intermediate radius, in particular, argue for bar-mediated resonances as the primary drivers of evolution in M94 at the present epoch. Similar processes may be governing the evolution of the ``core-dominated'' galaxies that have been observed at high redshift. The gravitationally-lensed ``Pretzel Galaxy'' (0024+1654) at a redshift of approximately 1.5 provides an important precedent in this regard.Comment: revised figure 1 (corrected coordinate labels on declination axis); 19 pages of text + 19 figures (jpg files); accepted for publication in A

    Identification of Dutch children diagnosed with atopic diseases using prescription data:a validation study

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    The aim of this study is to validate medication proxies for the identification of children diagnosed with atopic disorders that can be applied in various types of epidemiological research. Records of 7439 children, aged between 0 and 10 years, in the period 2001 until 2010, were retrieved from the Registration Network Groningen database, a general practitioners database in the north-eastern part of the Netherlands. The sensitivity and positive predictive value (PPV) of 22 medication proxies for the identification of children diagnosed with atopic disorders (asthma, atopic dermatitis, and allergic rhinitis) were computed using the registered diagnoses as gold standards. In addition, different capture periods (1 year, half year, and length of study period) for the detection of prescriptions were tested for all the medication proxies. The highest PPV (0.84, 95 % CI 0.81-0.87) in combination with a sufficient sensitivity value (0.54, 95 % CI 0.50-0.57) for the identification of children diagnosed with asthma was yielded for the medication proxy, a parts per thousand yen2 prescriptions for anti-asthma medication within 1 year, including 1 inhaled steroid. PPV and sensitivity were even higher in the age group 6-10 years. The proxies designed for the identification of children diagnosed with atopic dermatitis and allergic rhinitis yielded only high PPVs (a parts per thousand yen0.75) in combination with low sensitivity values (a parts per thousand currency sign0.22). Altering the capture period for the detection of prescriptions to half a year or the length of the study period only affected sensitivity values. Children diagnosed with asthma can be identified reliably with a range of medication proxies. The use of prescription data for the identification of children diagnosed with atopic dermatitis and allergic rhinitis is questionable

    Non-circular Gas Kinematics and Star Formation in the Ringed Galaxy NGC 4736

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    We analyze the gas kinematics and star formation properties of the nearby RSab galaxy NGC 4736 using interferometric and single-dish CO(1-0) data and previously published Halpha and HI data. The CO morphology is dominated by a central molecular bar and tightly wound spiral arms associated with a bright ring of star formation. Strong HI emission is also found in the ring, but HI is absent from the central regions. Comparison of the HI and Halpha distributions suggests that HI in the ring is primarily dissociated H2_2. Modeling of the CO kinematics reveals gas motion in elliptical orbits around the central bar, and we argue that the ring represents both the OLR of the bar and the ILR of a larger oval distortion. The HI kinematics show evidence for axisymmetric inflow towards the ring and are inconsistent with streaming in aligned elliptical orbits, but the highly supersonic (~40 km/s) inflow velocities required, corresponding to mass inflow rates of ~2 Msol/yr, suggest that more sophisticated models (e.g., gas orbiting in precessed elliptical orbits) should be considered. The radial CO and Halpha profiles are poorly correlated in the vicinity of the nuclear bar, but show a better correlation (in rough agreement with the Schmidt law) at the ring. Even along the ring, however, the azimuthal correspondence between CO and Halpha is poor, suggesting that massive stars form more efficiently at some (perhaps resonant) locations than at others. These results indicate that the star formation rate per unit gas mass exhibits strong spatial variations and is not solely a function of the available gas supply. The localization of star formation to the ring is broadly consistent with gravitational instability theory, although the instability parameter Q∼3Q \sim 3 on average in the ring, only falling below 1 in localized regions.Comment: Revised version accepted by ApJ, with new section on p-v diagrams. 24 pages with 24 figures (emulateapj5). Full resolution and color versions are available at http://astro.berkeley.edu/~twong/preprint

    The Effect of Provider Density on Lung Cancer Survival Among Blacks and Whites in the United States

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    IntroductionLung cancer mortality rates may vary with access to specialty providers and local resources. We sought to examine the effect of access to care, using density of lung cancer care providers, on lung cancer mortality among blacks and whites in the United States.MethodsWe examined U.S. county-level data for age-adjusted lung cancer mortality rates from 2003 to 2007. Our primary independent variable was per capita number of thoracic oncologic providers, adjusting for county-level smoking rates, socioeconomic status, and other geographic factors. Data were obtained from 2009 Area Resource File, National Center for Health Statistics, and the County Health Rankings Project.ResultsProviders of lung cancer care were unevenly distributed among the U.S. counties. For example, 41.4% of the U.S. population reside in counties with less than four thoracic surgeons per 100,000 people, 23.4% in counties with 4 to 15 surgeons per 100,000 people, and 35.3% in counties with more than 15 surgeons per 100,000 people. Geographically, 4.3% of whites compared with 11.2% of blacks lived in high lung cancer mortality zones. Lung cancer mortality did not vary by density of thoracic surgeons or oncology services; however, higher primary care provider density was associated with lung cancer mortality reduction of 4.1 per 100,000 for whites.ConclusionVariation in provider density for thoracic oncology in the United States was not associated with a difference in lung cancer mortality. Lower mortality associated with higher primary care provider density suggests that equitable access to primary care may lead to reduced cancer disparities

    AN IN VIVO MODEL OF HYPERACUTE REJECTION: CHARACTERIZATION AND EVALUATION OF THE EFFECT OF TRANSGENIC HUMAN COMPLEMENT INHIBITORS

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    Hyperacute rejection (HAR) occurring after transplantation within phylogenetically distant species is a severe reaction triggered by preexisting xenoreactive antibodies and complement activation, leading to the destruction of the donor organ. Expression of human complement inhibitors in transgenic pig organs prolongs the survival of xenograft in experimental models. Moreover, the extent of protection from hyperacute rejection is dependent on the level and site of expression of the transgenic molecules and, probably, on the combination of different molecules. In this regard a small animal model to test the efficacy of expression vectors and different human molecules could be very advantageous. A murine model developed in our laboratory was characterized by measurement of several parameters characteristic of HAR in the livers of control and transgenic mice expressing transgenic human DAF (CD55) or MCP (CD46) at the end of 2 h of perfusion with human plasma and after 1 day. The parameters studied were heamatological values of hepatic functions (GOT and GPT), induction of pro-inflammatory molecules and histopathological evaluation. Cytokines (IL-1 alpha, IL-1 beta, IL-6) induction and exposure of P-selectin on the endothelial cell surface, was only observed in control animals after 2 h of perfusion, as an early event. GOT and GPT values increase drammatically after 2 h perfusion and 1 day after the treatment according to the histopathological observation of liver damage. On the contrary, the livers of hDAF or hMCP transgenic mice, under the same treatment were significantly protected although the extent of this protection is dependent on the level of expression of transgenic human molecules

    Synthesis of Fluorine-18 Functionalized Nanoparticles for use as in vivo Molecular Imaging Agents

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    Nanoparticles containing fluorine-18 were prepared from block copolymers made by ring opening metathesis polymerization (ROMP). Using the fast initiating ruthenium metathesis catalyst (H_2IMes)(pyr)_2(Cl)_2Ru=CHPh, low polydispersity amphiphilic block copolymers were prepared from a cinnamoyl-containing hydrophobic norbornene monomer and a mesyl-terminated PEG-containing hydrophilic norbornene monomer. Self-assembly into micelles and subsequent cross-linking of the micelle cores by light-activated dimerization of the cinnamoyl groups yielded stable nanoparticles. Incorporation of fluorine-18 was achieved by nucleophilic displacement of the mesylates by the radioactive fluoride ion with 31% incorporation of radioactivity. The resulting positron-emitting nanoparticles are to be used as in vivo molecular imaging agents for use in tumor imaging
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