538 research outputs found

    Surfactant status and respiratory outcome in premature infants receiving late surfactant treatment.

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    BACKGROUND:Many premature infants with respiratory failure are deficient in surfactant, but the relationship to occurrence of bronchopulmonary dysplasia (BPD) is uncertain. METHODS:Tracheal aspirates were collected from 209 treated and control infants enrolled at 7-14 days in the Trial of Late Surfactant. The content of phospholipid, surfactant protein B, and total protein were determined in large aggregate (active) surfactant. RESULTS:At 24 h, surfactant treatment transiently increased surfactant protein B content (70%, p < 0.01), but did not affect recovered airway surfactant or total protein/phospholipid. The level of recovered surfactant during dosing was directly associated with content of surfactant protein B (r = 0.50, p < 0.00001) and inversely related to total protein (r = 0.39, p < 0.0001). For all infants, occurrence of BPD was associated with lower levels of recovered large aggregate surfactant, higher protein content, and lower SP-B levels. Tracheal aspirates with lower amounts of recovered surfactant had an increased proportion of small vesicle (inactive) surfactant. CONCLUSIONS:We conclude that many intubated premature infants are deficient in active surfactant, in part due to increased intra-alveolar metabolism, low SP-B content, and protein inhibition, and that the severity of this deficit is predictive of BPD. Late surfactant treatment at the frequency used did not provide a sustained increase in airway surfactant

    Tissue Type-Specific Expression of the dsRNA-Binding Protein 76 and Genome-Wide Elucidation of Its Target mRNAs

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    Background: RNA-binding proteins accompany all steps in the life of mRNAs and provide dynamic gene regulatory functions for rapid adjustment to changing extra-or intracellular conditions. The association of RNA-binding proteins with their targets is regulated through changing subcellular distribution, post-translational modification or association with other proteins. Methodology: We demonstrate that the dsRNA binding protein 76 (DRBP76), synonymous with nuclear factor 90, displays inherently distinct tissue type-specific subcellular distribution in the normal human central nervous system and in malignant brain tumors of glial origin. Altered subcellular localization and isoform distribution in malignant glioma indicate that tumor-specific changes in DRBP76-related gene products and their regulatory functions may contribute to the formation and/or maintenance of these tumors. To identify endogenous mRNA targets of DRBP76, we performed RNA-immunoprecipitation and genome-wide microarray analyses in HEK293 cells, and identified specific classes of transcripts encoding critical functions in cellular metabolism. Significance: Our data suggest that physiologic DRBP76 expression, isoform distribution and subcellular localization are profoundly altered upon malignant transformation. Thus, the functional role of DRBP76 in co- or post-transcriptional gene regulation may contribute to the neoplastic phenotype

    Evidence for an increase in cosmogenic 10Be during a geomagnetic reversal

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    Reversals in the geomagnetic field, which occur every few hundred thousand years, represent a dramatic change in the Earth's environment. Although there is no satisfactory theory for such reversals, it is generally accepted that the dipole field intensity decreases to <20% of its 'normal' value for a few thousand years during the change in direction. Because the galactic and solar cosmic rays which impinge on the Earth's atmosphere are charged, a significant fraction (about half) of them are deflected by the geomagnetic field. At the time of a reversal, this magnetic shielding is greatly reduced, and it has been suggested that the increased flux of high-energy particles could have effects on evolutionary or climatic processes. For example, the statistically significant coincidence in levels of some marine faunal extinctions and reversal boundaries in ocean sediments could be caused, directly or indirectly, by the decreased geomagnetic intensity during the reversal. We report here evidence in marine sediments for an increase in cosmogenic 10Be production in the Earth's atmosphere during the Brunhes-Matuyama reversal 730,000 yr ago. In addition to confirming an increase in cosmogenic isotope production, the results provide information on the magnitude and duration of the geomagnetic intensity decrease during such an event, and the depth at which remanent magnetism is acquired in marine sediments

    The Pioneer Anomaly

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    Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20-70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ~6 x 10^{-9} Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2. This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.Comment: 165 pages, 40 figures, 16 tables; accepted for publication in Living Reviews in Relativit

    Intuitive eating and the nutrition transition in Asia

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    Current models of the nutrition transition focus on demographic changes and economic development. A further influence may be the adoption of western-based perceptions of beauty that lead to potentially harmful eating behaviours which contribute to overweight, obesity, and eating disorders. This paper proposes a comprehensive model of the nutrition transition that includes western influences on perceived attractiveness and subsequent eating styles. An exploratory test of this model for Asian countries explores differences in intuitive eating as a function of economic development and the adoption of western standards of beauty. The intuitive eating scale (IES), a measure of food consumption that is primarily characterized by the satisfaction of physical hunger, was used to evaluate agreement with intuitive eating principles in the US and four Asian countries (Japan, Thailand, the Philippines, and China). Although intuitive eating scores in the US and Thailand failed to follow predicted patterns on two of the four IES subscales, scores for the other two IES subscales and the total IES score followed predicted patterns for Asian countries. Intuitive eating appears to be a valid, measurable concept that is correlated with economic development and levels of western influence in Asian countries. The tentative findings of this exploratory study support further evaluation of cultural influences as an important component of the nutrition transition

    Results of a participatory needs assessment demonstrate an opportunity to involve people who use alcohol in drug user activism and harm reduction

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    BACKGROUND: Drug users’ organizations have made progress in recent years in advocating for the health and human rights of people who use illicit drugs but have historically not emphasized the needs of people who drink alcohol. METHODS: This paper reports on a qualitative participatory needs assessment with people who use illicit substances in British Columbia, Canada. We held workshops in 17 communities; these were facilitated by people who use illicit drugs, recorded with ethnographic fieldnotes, and analyzed using critical theory. RESULTS: Although the workshops were targeted to people who use illicit drugs, people who primarily consume alcohol also attended. An unexpected finding was the potential for drug users’ organizations and other harm reduction programs to involve “illicit drinkers”: people who drink non-beverage alcohol (e.g. mouthwash, rubbing alcohol) and those who drink beverage alcohol in criminalized ways (e.g., homeless drinkers). Potential points of alliance between these groups are common priorities (specifically, improving treatment by health professionals and the police, expanding housing options, and implementing harm reduction services), common values (reducing surveillance and improving accountability of services), and polysubstance use. CONCLUSIONS: Despite these potential points of alliance, there has historically been limited involvement of illicit drinkers in drug users’ activism. Possible barriers to involvement of illicit drinkers in drug users’ organizations include racism (as discourses around alcohol use are highly racialized), horizontal violence, the extreme marginalization of illicit drinkers, and knowledge gaps around harm reduction for alcohol. Understanding the commonalities between people who use drugs and people who use alcohol, as well as the potential barriers to alliance between them, may facilitate the greater involvement of illicit drinkers in drug users’ organizations and harm reduction services

    Spectroscopic Evidence for an Oxazolone Structure in Anionic b-Type Peptide Fragments

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    Infrared spectra of anionic b-type fragments generated by collision induced dissociation (CID) from deprotonated peptides are reported. Spectra of the b2 fragments of deprotonated AlaAlaAla and AlaTyrAla have been recorded over the 800–1800 cm–1 spectral range by multiple-photon dissociation (MPD) spectroscopy using an FTICR mass spectrometer in combination with the free electron laser FELIX. Structural characterization of the b-type fragments is accomplished by comparison with density functional theory calculated spectra at the B3LYP/6-31++G(d,p) level for different isomeric structures. Although diketopiperazine structures represent the energetically lowest isomers, the IR spectra suggest an oxazolone structure for the b2 fragments of both peptides. Deprotonation is shown to occur on the oxazolone α-carbon, which leads to a conjugated structure in which the negative charge is practically delocalized over the entire oxazolone ring, providing enhanced gas-phase stability

    Patterns of Childhood Trauma and Psychological Distress among Injecting Heroin Users in China

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    Background: Childhood trauma has been reported as a possible cause of future substance abuse in some countries. This study reports the prevalence of childhood trauma and examines its association with psychological distress among injecting drug users from mainland China. Methodology: The study was conducted in three government-operated drug rehabilitation facilities in Shanghai, China in 2007. The Early Trauma Inventory Self Report-Short Form (ETISR-SF) was used to evaluate 4 types (general, emotional, physical and sexual) and severity of childhood trauma, and the Symptom Checklist-90-Revised (SCL-90-R) to evaluate psychological distress. Principal Findings: Among 341 injecting drug users who completed the study, about 80 % reported one or more types o
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