1,547 research outputs found
A randomized trial of nebulized 3% hypertonic saline with salbutamol in the treatment of acute bronchiolitis in hospitalized infants
OBJECTIVE:
Acute bronchiolitis is a common disorder of infants that often results in hospitalization. Apart from supportive care, no therapy has been shown to influence the course of the disease, except for a possible effect of nebulized hypertonic saline (HS). To determine whether this does have beneficial effects on length of stay in hospital or on severity scores, we undertook a double-blind, randomized, controlled trial in a pediatric department of a Portuguese hospital.
METHODS:
Previously healthy infants, younger than 12 months, hospitalized with mild-to-moderate acute viral bronchiolitis were randomized to receive either nebulized 3% (hypertonic, HS) or 0.9% (normal, NS) saline during their entire hospital stay. Primary endpoints were: length of hospital stay and severity scores on each day of hospitalization. Need for supplemental oxygen, further add-on medications and adverse effects were also analyzed.
RESULTS:
Sixty-eight patients completed the study (HS: 33; NS: 35). The median length of hospital stay did not differ between groups: HS: 5.6 ± 2.3 days; NS: 5.4 ± 2.1 days (P = 0.747). We found no difference between groups in severity scores from day 1 to day 4. There were no differences in need for supplemental oxygen or add-on medications. Patients in HS group had significantly more cough (46% vs. 20%, P = 0.025) and rhinorrhoe (58% vs. 31%, P = 0.30).
CONCLUSION:
This study does not support the use of nebulized HS over NS in therapy of hospitalized children with mild-to-moderate acute viral bronchioliti
The blp locus of Streptococcus pneumoniae plays a limited role in the selection of which strains can co-colonize the human nasopharynx.
Nasopharyngeal colonization is important for Streptococcus pneumoniae evolution, providing the opportunity for horizontal gene transfer when multiple strains co-occur. Although colonization with more than one strain of pneumococcus is common, the factors that influence the ability of strains to co-exist are not known. A highly variable blp (bacteriocin-like peptide) locus has been identified in all sequenced strains of S. pneumoniae This locus controls the regulation and secretion of bacteriocins, small peptides that target other bacteria. In this study, we analyzed a series of co-colonizing isolates to evaluate the impact of the blp locus on human colonization to determine whether competitive phenotypes of bacteriocin secretion restrict co-colonization.We identified a collection of 135 nasopharyngeal samples with two or more strains totaling 285 isolates. The blp locus of all strains was characterized genetically with regards to pheromone type, bacteriocin/immunity content and potential for locus functionality. Inhibitory phenotypes of bacteriocin secretion and locus activity were assessed through overlay assays. Isolates from single colonization (n=298) were characterized for comparison.Co-colonizing strains had a high diversity of blp cassettes; approximately one third displayed an inhibitory phenotype in vitro Despite in vitro evidence of competition, pneumococci co-colonized individuals independently of their blp pheromone type (p=0.577), bacteriocin/immunity content, blp locus activity (p=0.798) and inhibitory phenotype (p=0.716). In addition, no significant differences were observed when single and co-colonizing strains were compared.Despite clear evidence of blp-mediated competition in experimental models, our study suggests that the blp locus plays a limited role in restricting pneumococcal co-colonization in humans. IMPORTANCE: Nasopharyngeal colonization with Streptococcus pneumoniae (pneumococcus) is important for pneumococcal evolution as it represents the major site for horizontal gene transfer when multiple strains co-occur, a phenomenon known as co-colonization. Understanding how pneumococcal strains interact within the competitive environment of the nasopharynx is of chief importance in the context of pneumococcal ecology. In this study we used an unbiased collection of naturally co-occurring pneumococcal strains and showed that a biological process frequently used by bacteria for competition - bacteriocin production - is not decisive in the co-existence of pneumococci in the host, contrary to what has been shown in experimental models
Intrastrain genomic and phenotypic variability of the commercial Saccharomyces cerevisiae strain Zymaflore VL1 reveals microevolutionary adaptation to vineyard environments
The maintenance of microbial species in different environmental conditions is associated with adaptive microevolutionary changes that are shown here to occur within the descendants of the same strain in comparison with the commercial reference strain. However, scarce information is available regarding changes that occur among strain descendants during their persistence in nature. Herein we evaluate genome variations among four isolates of the commercial winemaking strain Saccharomyces cerevisiae Zymaflore VL1 that were re-isolated from vineyards surrounding wineries where this strain was applied during several years, in comparison with the commercial reference strain. Comparative genome hybridization showed amplification of 14 genes among the recovered isolates being related with mitosis, meiosis, lysine biosynthesis, galactose and asparagine catabolism, besides 9 Ty elements. The occurrence of microevolutionary changes was supported by DNA sequencing that revealed 339-427 SNPs and 12-62 indels. Phenotypic screening and metabolic profiles also distinguished the recovered isolates from the reference strain. We herein show that the transition from nutrient-rich musts to nutritionally scarce natural environments induces adaptive responses and microevolutionary changes promoted by Ty elements and by nucleotide polymorphisms that were not detected in the reference strain.Ricardo Franco-Duarte and Ines Mendes are recipients of a fellowship from the Portuguese Science Foundation, FCT (SFRH/BD/48591/2008, SFRH/BD/74798/2010, respectively). Financial support was obtained from FEDER funds through the program COMPETE, by national funds through FCT by the projects FCOMP-01-0124-008775 (PTDC/AGR-ALI/103392/2008) and PTDC/AGR-ALI/121062/2010, and through the strategic funding UID/BIA/04050/2013.info:eu-repo/semantics/publishedVersio
The Influence of Thermal Comfort on the Quality of Life of Nursing Home Residents
Thermal comfort (TC) parameters were measured in 130 rooms from nursing homes (NH), following ISO 7730:2005 in order to evaluate the influence of winter season TC indices on quality of life (QoL) in older individuals. Mean radiant temperature (mrT), predicted mean vote (PMV) and predicted percent of dissatisfied people (PPD) indices, and the respective measurement uncertainties were calculated using Monte Carlo Method. The WHOQOL-BREF questionnaire was conducted from September 2012 to April 2013, during the winter season TC sampling campaign. Winter PMV and PPD indices showed significant differences between seasons in median values for comfort. There were also significant differences between seasons for air temperature, air velocity, mrT, and relative humidity. The winter PMV index displayed a “slightly cool” [≤−1] to “cool” [≤−2] in thermal sensation scale [−3 to 3]. PPD index reflected this discomfort as evidenced by a high rate of predicted dissatisfied occupants (64%). The influence of winter season TC on older individual QoL results demonstrated that values of PMV above −0.7 had higher mean score of QoL (coefficient estimate: 11.13 units) compared with values of PMV below −0.7. These findings are of relevance to public health and may be useful for understanding NH indoor environment variables thus implementing preventive policies in terms of standards and guidelines for these susceptible populations.This work was supported by GERIA Project (www.geria.webnode.com): PTDC/SAU-SAP/116563/2010 and a PhD Grant (SFRH/BD/72399/2010) from Foundation for Science and Technology (Fundação para a Ciência e Tecnologia - FCT) through Operational Competitiveness Programme (COMPETE) as part of the National Strategic Reference Framework. SB work was supported by a grant funded by AIRC (Associazione Italiana per la Ricerca sul Cancro)
Advancing Tests of Relativistic Gravity via Laser Ranging to Phobos
Phobos Laser Ranging (PLR) is a concept for a space mission designed to
advance tests of relativistic gravity in the solar system. PLR's primary
objective is to measure the curvature of space around the Sun, represented by
the Eddington parameter , with an accuracy of two parts in ,
thereby improving today's best result by two orders of magnitude. Other mission
goals include measurements of the time-rate-of-change of the gravitational
constant, and of the gravitational inverse square law at 1.5 AU
distances--with up to two orders-of-magnitude improvement for each. The science
parameters will be estimated using laser ranging measurements of the distance
between an Earth station and an active laser transponder on Phobos capable of
reaching mm-level range resolution. A transponder on Phobos sending 0.25 mJ, 10
ps pulses at 1 kHz, and receiving asynchronous 1 kHz pulses from earth via a 12
cm aperture will permit links that even at maximum range will exceed a photon
per second. A total measurement precision of 50 ps demands a few hundred
photons to average to 1 mm (3.3 ps) range precision. Existing satellite laser
ranging (SLR) facilities--with appropriate augmentation--may be able to
participate in PLR. Since Phobos' orbital period is about 8 hours, each
observatory is guaranteed visibility of the Phobos instrument every Earth day.
Given the current technology readiness level, PLR could be started in 2011 for
launch in 2016 for 3 years of science operations. We discuss the PLR's science
objectives, instrument, and mission design. We also present the details of
science simulations performed to support the mission's primary objectives.Comment: 25 pages, 10 figures, 9 table
The Pioneer Anomaly
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
CO2 Concentration in Day Care Centres is Related to Wheezing in Attending Children
Poor ventilation at day care centres (DCCs) was already reported, although its effects on attending children are not clear. This study aimed to evaluate the association between wheezing in children and indoor CO2 (a ventilation surrogate marker) in DCC and to identify behaviours and building
characteristics potentially related to CO2. In phase I, 45 DCCs from Lisbon and Oporto (Portugal) were selected through a
proportional stratified random sampling. In phase II, 3 months later, 19 DCCs were further reassessed after cluster analysis
for the greatest difference comparison. In both phases, children’s respiratory health was assessed by ISAAC-derived
questionnaires. Indoor CO2 concentrations and building characteristics of the DCC were evaluated in both phases, using complementary methods. Mixed effect models were used to analyze the data. In phase I, which included 3,186 children (mean age 3.1±1.5 years), indoor CO2 concentration
in the DCC rooms was associated with reported wheezing in the past 12months (27.5 %) (adjusted odds ratio (OR) for each
increase of 200 ppm 1.04, 95 % CI 1:01 to 1:07). In phase II, the association in the subsample of 1,196 children seen in 19
out of the initial 45 DCCs was not significant (adjusted OR 1.02, 95 % CI 0.96 to 1.08). Indoor CO2 concentration was
inversely associated with the practices of opening Windows and internal doors and with higher wind velocity. A positive trend was observed between CO2 and prevalence of reported asthma (4.7 %). Conclusion: Improved ventilation is needed to achieve a healthier indoor environment in DCC
Captive-born collared peccary (Pecari tajacu, Tayassuidae) fails to discriminate between predator and non-predator models
Captive animals may lose the ability to recognize their natural predators, making conservation programs more susceptible to
failure if such animals are released into the wild. Collared peccaries are American tayassuids that are vulnerable to local
extinction in certain areas, and conservation programs are being conducted. Captive-born peccaries are intended for release into
the wild in Minas Gerais state, southeastern Brazil. In this study, we tested the ability of two groups of captive-born collared
peccaries to recognize their predators and if they were habituated to humans. Recognition tests were performed using models of
predators (canids and felids) and non-predators animals, as well as control objects, such as a plastic chair; a human was also
presented to the peccaries, and tested as a separate stimulus. Anti-predator defensive responses such as fleeing and threatening
displayswere not observed in response to predator models. Predator detection behaviors both from visual and olfactory cues were displayed, although they were not specifically targeted at predator models. These results indicate that collared peccaries were unable to recognize model predators. Habituation effects, particularly on anti-predator behaviors, were observed both with a 1-h model presentation and across testing days. Behavioral responses to humans did not differ from those to other models. Thus, if these animals were to be released into the wild, they should undergo anti-predator training sessions to enhance their chances of survival
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