277 research outputs found
Polymerase Chain Reaction Screening for Fungemia and/or Invasive Fungal Infections in Patients with Hematologic Malignancies
INTRODUCTION: Invasive fungal infections (IFIs) are a life-threatening complication in patients with hematologic malignancies, mainly in acute leukemia patients, following chemotherapy. IFI incidence is increasing, and associated mortality remains high due to unreliable diagnosis. Antifungal drugs are often limited by inadequate antimicrobial spectrum and side effects. Thus, the detection of circulating fungal DNA has been advocated as a rapid, more sensitive diagnostic tool.
PATIENTS AND METHODS: Between June 01 and January 03, weekly blood samples (1,311) were screened from 193 patients undergoing intensive myelosuppressive or immunosuppressive therapy. IFI cases were classified according to European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. Fungal DNA was extracted from whole blood and amplified using polymerase chain reaction (PCR) published primers that bind to the conserved regions of the fungal 18S rRNA gene sequence. In our study, two or more consecutive positive samples were always associated with fungal disease.
RESULTS: PCR screening predicted the development of IFI to be 17 days (median). This test had a specificity of 91.1% and a sensitivity of 75%. IFI incidence was 7.8%.
DISCUSSION: Therefore, our results confirm the potential usefulness of PCR serial screening and the clinical applicability in everyday routine. PCR screening offers a noninvasive repeatable aid to the diagnosis of IFI
Two rapid assays for screening of patulin biodegradation
ArtĂculo sobre distintos ensayos para comprobar la biodegradaciĂłn de la patulinaThe mycotoxin patulin is produced by the blue
mould pathogen Penicillium expansum in rotting apples
during postharvest storage. Patulin is toxic to a wide range
of organisms, including humans, animals, fungi and bacteria.
Wash water from apple packing and processing
houses often harbours patulin and fungal spores, which can
contaminate the environment. Ubiquitous epiphytic yeasts,
such as Rhodosporidium kratochvilovae strain LS11 which
is a biocontrol agent of P. expansum in apples, have the
capacity to resist the toxicity of patulin and to biodegrade
it. Two non-toxic products are formed. One is desoxypatulinic
acid. The aim of the work was to develop rapid,
high-throughput bioassays for monitoring patulin degradation
in multiple samples. Escherichia coli was highly
sensitive to patulin, but insensitive to desoxypatulinic acid.
This was utilized to develop a detection test for patulin,
replacing time-consuming thin layer chromatography or
high-performance liquid chromatography. Two assays for patulin degradation were developed, one in liquid medium
and the other in semi-solid medium. Both assays allow the
contemporary screening of a large number of samples. The
liquid medium assay utilizes 96-well microtiter plates and
was optimized for using a minimum of patulin. The semisolid
medium assay has the added advantage of slowing
down the biodegradation, which allows the study and isolation
of transient degradation products. The two assays are
complementary and have several areas of utilization, from
screening a bank of microorganisms for biodegradation
ability to the study of biodegradation pathways
Detection of dark galaxies and circum-galactic filaments fluorescently illuminated by a quasar at z=2.4
A deep narrow-band survey for Ly-alpha emission carried out on the VLT-FORS2
has revealed 98 Ly-alpha candidates down to a flux limit of 4.e-18 erg/s/cm^2
in a volume of 5500 comoving Mpc^3 at z=2.4 centered on the hyperluminous
quasar HE0109-3518. The properties of the detected sources in terms of their i)
equivalent width distribution, ii) luminosity function, and iii) the average
luminosity versus projected distance from the quasar, all suggest that a large
fraction of these objects have been fluorescently "illuminated" by HE0109-3518.
This conclusion is supported by comparison with detailed radiative transfer
simulations of the effects of the quasar illumination. 18 objects have a
rest-frame Equivalent Width (EW0) larger than 240A, the expected limit for
Ly-alpha emission powered by Population II star formation and 12 sources among
these do not have any continuum counterpart in a deep V-band imaging of the
same field. For these, a stacking analysis indicates EW0>800A, effectively
ruling out Ly-alpha powered by internal star formation. These sources are thus
the best candidates so far for proto-galactic clouds or "dark" galaxies at
high-redshift, whose existence has recently been suggested by several
theoretical studies. Assuming they are mostly ionized by the quasar radiation,
we estimate that their gas masses would be about 10^9 Msun implying that their
star formation efficiencies (SFE) are less than 1.e-11 yr^-1 several times
below the SFE of the most gas-rich dwarf galaxies locally, and five hundred
times lower than typical massive star-forming galaxies at z~2. We have also
discovered extended, filamentary gas, also likely illuminated by the quasar,
around some of the brightest continuum-detected sources with EW0>240A. This
emission is compatible with the expectations for circum-galactic cold streams
but other origins, including tidal stripping, are also possible.Comment: 26 pages, 16 figures; MNRAS in press (accepted 2012 Jun 15); minor
changes from previous version, typos corrected, references adde
Clues to the nature of damped Lyman alpha systems from chemical evolution models
The evolution of the metallicity of damped Lyman alpha systems (DLAs) is
investigated in order to understand the nature of these systems. The
observational data on chemical abundances of DLAs are analysed with robust
statistical methods, and the abundances are corrected for dust depletion. The
results of this analysis are compared to predictions of several classes of
chemical evolution models: one-zone dwarf galaxy models, multizone disk models,
and chemodynamical models representing dwarf galaxies. We compare the
observational data on the [alpha/Fe] and [N/alpha] ratios to the predictions
from the models. In DLAs, these ratios are only partially reproduced by the
dwarf galaxy one-zone model and by the disk model. On the other hand, the
chemodynamical model for dwarf galaxies reproduces the properties of nearly all
DLAs. We derive the formation epoch of dwarf galaxies, and we find that dwarf
galaxies make a significant contribution to the total neutral gas density in
DLAs, and that this contribution is more important at high redshifts (z > 2-3).
We propose a scenario in which the DLA population is dominated by dwarf
galaxies at high redshifts and by disks at lower redshifts. We also find that
Lyman Break Galaxies (LBGs) may constitute a sequence rather than present a
sharp dichotomy between the two populations. We also arise the possibility that
we could be missing a whole population of high HI density column objects, with
metallicities intermediate between those of DLAs and LBGs. Finally, we discuss
the possibility that relying only on the observations of DLAs could lead to an
underestimate of the metal content of the high redshift Universe.Comment: 23 pages, 19 figures. Accepted for publication in MNRA
Effects of bromopride on the healing of left colon anastomoses of rats
Objetivo: Avaliar os efeitos da bromoprida sobre a formação de aderĂȘncias e a cicatrização de anastomoses de cĂłlon esquerdo de
ratos. MĂ©todos: Foram incluĂdos 40 ratos, divididos em dois grupos contendo 20 animais, para administração de bromoprida (grupo
de estudo- E) ou solução fisiológica (grupo controle- C). Cada grupo foi dividido em subgrupos contendo 10 animais cada, para
eutanåsia no terceiro (E3 e C3) ou no sétimo dia (E7 e C7) de pós-operatório. Os ratos foram submetidos à secção do cólon esquerdo
e anastomose tĂ©rmino-terminal. No dia da relaparotomia, foi avaliada a quantidade total de aderĂȘncias e removido um segmento
colÎnico contendo a anastomose para anålise histopatológica, da força de ruptura e da concentração de hidroxiprolina. Resultados:
NĂŁo houve diferença entre os grupos em relação Ă evolução clĂnica. Dois animais do grupo de estudo apresentaram deiscĂȘncia
de anastomose bloqueada. Os animais que receberam bromoprida apresentaram nĂșmero de aderĂȘncias intracavitĂĄrias e aderĂȘncias
Ă anastomose semelhantes ao grupo controle. As anastomoses dos animais do grupo E3 apresentaram menor resistĂȘncia de ruptura
do que as do grupo C3 (p=0,04). Este efeito não ocorreu no sétimo dia de pós-operatório (p=0,37). Não houve diferença significativa
entre os grupos em relação à histopatologia ou concentração de hidroxiprolina das anastomoses. Conclusão: O uso da bromoprida
estĂĄ associado Ă diminuição da resistĂȘncia tĂȘnsil de anastomoses do cĂłlon esquerdo de ratos no terceiro dia de pĂłs-operatĂłrio.Objective: To evaluate the effects of bromopride on the formation of adhesions and anastomotic healing in the left colon of rats.
Methods: We divided 40 rats into two groups of 20 animals, administration of bromopride (study group-E) or saline (control group-
C). Each group was divided into subgroups containing 10 animals each for euthanasia in the third (C3 and E3) or the seventh (E7 and
C7) postoperative days. The rats were submitted to section of the left colon and end-to-end anastomosis. On the day of reoperation,
we evaluated the total amount of adhesions and removed a colonic segment containing the anastomosis for histopathological
analysis, assessment of rupture strength and hydroxyproline concentration. Results: There was no difference between groups in
relation to clinical outcome. Two animals in the study group had blocked anastomotic leakage. The animals that received bromopride
had the number of intracavitary adhesions and adhesions to the anastomosis similar to the control group. The anastomoses from the
group E3 animals showed lower resistance to rupture the one from the C3 group (p = 0.04). This effect did not occur on the seventh
postoperative day (p = 0.37). There was no significant difference between groups in relation to histopathology and hydroxyproline
concentration in the anastomoses. Conclusion: The use of bromopride was associated with decreased tensile strength of left colon
anastomosis in rats in the third postoperative day
Galaxy Formation Theory
We review the current theory of how galaxies form within the cosmological
framework provided by the cold dark matter paradigm for structure formation.
Beginning with the pre-galactic evolution of baryonic material we describe the
analytical and numerical understanding of how baryons condense into galaxies,
what determines the structure of those galaxies and how internal and external
processes (including star formation, merging, active galactic nuclei etc.)
determine their gross properties and evolution. Throughout, we highlight
successes and failings of current galaxy formation theory. We include a review
of computational implementations of galaxy formation theory and assess their
ability to provide reliable modelling of this complex phenomenon. We finish
with a discussion of several "hot topics" in contemporary galaxy formation
theory and assess future directions for this field.Comment: 58 pages, to appear in Physics Reports. This version includes minor
corrections and a handful of additional reference
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