685 research outputs found
Evaluación de la hemostasis
We try to explain the coagulation mechanism evaluation through our own clinical experience
Gastropatía hipertrófica de píloro : resolución quirúrgica de tres casos clínicos mediante la técnica de píloroplastia Y-U
Descripción de la técnica de piloroplastia en colgajo antral y-U en la resolución de 3 casos clínicos de gastropatía por hipertrofia crónica del píloro.Description of the y-U antral flap advancement pyloroplasty to the resolution of 3 clinic cases of chronic hypertrophic pyloric gastropathy
Probing the Early Evolution of Young High-Mass Stars
Near-infrared imaging surveys of high-mass star-forming regions reveal an
amazingly complex interplay between star formation and the environment
(Churchwell et al. 2006; Alvarez et al. 2004). By means of near-IR spectroscopy
the embedded massive young stars can be characterized and placed in the context
of their birth site. However, so far spectroscopic surveys have been hopelessly
incomplete, hampering any systematic study of these very young massive stars.
New integral field instrumentation available at ESO has opened the possibility
to take a huge step forward by obtaining a full spectral inventory of the
youngest massive stellar populations in star-forming regions currently
accessible. Simultaneously, the analysis of the extended emission allows the
characterization of the environmental conditions. The Formation and Early
Evolution of Massive Stars (FEMS) collaboration aims at setting up a large
observing campaign to obtain a full census of the stellar content, ionized
material, outflows and PDR's over a sample of regions that covers a large
parameter space. Complementary radio, mm and infrared observations will be used
for the characterization of the deeply embedded population. For the first eight
regions we have obtained 40 hours of SINFONI observations. In this
contribution, we present the first results on three regions that illustrate the
potential of this strategy.Comment: To appear in ASP Conf. Proceedings of "Massive Star Formation:
Observations confront Theory", H. Beuther et al. (eds.), held in Heidelberg,
September 200
ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution
We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm
continuum images of the asteroid 3 Juno obtained with an angular resolution of
0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4
hr interval, which covers 60% of the 7.2 hr rotation period, approximately
centered on local transit. A sequence of ten consecutive images reveals
continuous changes in the asteroid's profile and apparent shape, in good
agreement with the sky projection of the three-dimensional model of the
Database of Asteroid Models from Inversion Techniques. We measure a geometric
mean diameter of 259pm4 km, in good agreement with past estimates from a
variety of techniques and wavelengths. Due to the viewing angle and inclination
of the rotational pole, the southern hemisphere dominates all of the images.
The median peak brightness temperature is 215pm13 K, while the median over the
whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find
that the brightness temperature varies across the surface with higher values
correlated to the subsolar point and afternoon areas, and lower values beyond
the evening terminator. The dominance of the subsolar point is accentuated in
the final four images, suggesting a reduction in the thermal inertia of the
regolith at the corresponding longitudes, which are possibly correlated to the
location of the putative large impact crater. These results demonstrate ALMA's
potential to resolve thermal emission from the surface of main belt asteroids,
and to measure accurately their position, geometric shape, rotational period,
and soil characteristics.Comment: 8 pages, 3 figures, 2 tables, accepted for publication in the
Astrophysical Journal Letter
Hedgehog pathway mutations drive oncogenic transformation in high-risk T-cell acute lymphoblastic leukemia.
The role of Hedgehog signaling in normal and malignant T-cell development is controversial. Recently, Hedgehog pathway mutations have been described in T-ALL, but whether mutational activation of Hedgehog signaling drives T-cell transformation is unknown, hindering the rationale for therapeutic intervention. Here, we show that Hedgehog pathway mutations predict chemotherapy resistance in human T-ALL, and drive oncogenic transformation in a zebrafish model of the disease. We found Hedgehog pathway mutations in 16% of 109 childhood T-ALL cases, most commonly affecting its negative regulator PTCH1. Hedgehog mutations were associated with resistance to induction chemotherapy (P = 0.009). Transduction of wild-type PTCH1 into PTCH1-mutant T-ALL cells induced apoptosis (P = 0.005), a phenotype that was reversed by downstream Hedgehog pathway activation (P = 0.007). Transduction of most mutant PTCH1, SUFU, and GLI alleles into mammalian cells induced aberrant regulation of Hedgehog signaling, indicating that these mutations are pathogenic. Using a CRISPR/Cas9 system for lineage-restricted gene disruption in transgenic zebrafish, we found that ptch1 mutations accelerated the onset of notch1-induced T-ALL (P = 0.0001), and pharmacologic Hedgehog pathway inhibition had therapeutic activity. Thus, Hedgehog-activating mutations are driver oncogenic alterations in high-risk T-ALL, providing a molecular rationale for targeted therapy in this disease
First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations
from the 2014 Long Baseline Campaign in dust continuum and spectral line
emission from the HL Tau region. The continuum images at wavelengths of 2.9,
1.3, and 0.87 mm have unprecedented angular resolutions of 0.075 arcseconds (10
AU) to 0.025 arcseconds (3.5 AU), revealing an astonishing level of detail in
the circumstellar disk surrounding the young solar analogue HL Tau, with a
pattern of bright and dark rings observed at all wavelengths. By fitting
ellipses to the most distinct rings, we measure precise values for the disk
inclination (46.72pm0.05 degrees) and position angle (+138.02pm0.07 degrees).
We obtain a high-fidelity image of the 1.0 mm spectral index (), which
ranges from in the optically-thick central peak and two
brightest rings, increasing to 2.3-3.0 in the dark rings. The dark rings are
not devoid of emission, we estimate a grain emissivity index of 0.8 for the
innermost dark ring and lower for subsequent dark rings, consistent with some
degree of grain growth and evolution. Additional clues that the rings arise
from planet formation include an increase in their central offsets with radius
and the presence of numerous orbital resonances. At a resolution of 35 AU, we
resolve the molecular component of the disk in HCO+ (1-0) which exhibits a
pattern over LSR velocities from 2-12 km/s consistent with Keplerian motion
around a ~1.3 solar mass star, although complicated by absorption at low
blue-shifted velocities. We also serendipitously detect and resolve the nearby
protostars XZ Tau (A/B) and LkHa358 at 2.9 mm.Comment: 11 pages, 5 figures, 2 tables, accepted for publication in the
Astrophysical Journal Letter
PIK3CA dependence and sensitivity to therapeutic targeting in urothelial carcinoma
Background
Many urothelial carcinomas (UC) contain activating PIK3CA mutations. In telomerase-immortalized normal urothelial cells (TERT-NHUC), ectopic expression of mutant PIK3CA induces PI3K pathway activation, cell proliferation and cell migration. However, it is not clear whether advanced UC tumors are PIK3CA-dependent and whether PI3K pathway inhibition is a good therapeutic option in such cases.
Methods
We used retrovirus-mediated delivery of shRNA to knock down mutant PIK3CA in UC cell lines and assessed effects on pathway activation, cell proliferation, migration and tumorigenicity. The effect of the class I PI3K inhibitor GDC-0941 was assessed in a panel of UC cell lines with a range of known molecular alterations in the PI3K pathway.
Results
Specific knockdown of PIK3CA inhibited proliferation, migration, anchorage-independent growth and in vivo tumor growth of cells with PIK3CA mutations. Sensitivity to GDC-0941 was dependent on hotspot PIK3CA mutation status. Cells with rare PIK3CA mutations and co-occurring TSC1 or PTEN mutations were less sensitive. Furthermore, downstream PI3K pathway alterations in TSC1 or PTEN or co-occurring AKT1 and RAS gene mutations were associated with GDC-0941 resistance.
Conclusions
Mutant PIK3CA is a potent oncogenic driver in many UC cell lines and may represent a valuable therapeutic target in advanced bladder cancer
The Effects of Previous Misestimation of Task Duration on Estimating Future Task Duration
It is a common time management problem that people underestimate the duration of tasks, which has been termed the "planning fallacy." To overcome this, it has been suggested that people should be informed about how long they previously worked on the same task. This study, however, tests whether previous misestimation also affects the duration estimation of a novel task, even if the feedback is only self-generated. To test this, two groups of participants performed two unrelated, laboratory-based tasks in succession. Learning was manipulated by permitting only the experimental group to retrospectively estimate the duration of the first task before predicting the duration of the second task. Results showed that the experimental group underestimated the duration of the second task less than the control group, which indicates a general kind of learning from previous misestimation. The findings imply that people could be trained to carefully observe how much they misestimate task duration in order to stimulate learning. The findings are discussed in relation to the anchoring account of task duration misestimation and the memory-bias account of the planning fallacy. © 2014 Springer Science+Business Media New York
Reversal of oncogene transformation and suppression of tumor growth by the novel IGF1R kinase inhibitor A-928605
BACKGROUND: The insulin-like growth factor (IGF) axis is an important signaling pathway in the growth and survival of many cell and tissue types. This pathway has also been implicated in many aspects of cancer progression from tumorigenesis to metastasis. The multiple roles of IGF signaling in cancer suggest that inhibition of the pathway might yield clinically effective therapeutics. METHODS: We describe A-928605, a novel pyrazolo [3,4-d]pyrimidine small molecule inhibitor of the receptor tyrosine kinases (IGF1R and IR) responsible for IGF signal transduction. This compound was first tested for its activity and selectivity via conventional in vitro kinome profiling and cellular IGF1R autophosphorylation. Additionally, cellular selectivity and efficacy of A-928605 were analyzed in an IGF1R oncogene-addicted cell line by proliferation, signaling and microarray studies. Finally, in vivo efficacy of A-928605 was assessed in the oncogene-addicted cell line and in a neuroblastoma model as a single agent as well as in combination with clinically approved therapeutics targeting EGFR in models of pancreatic and non-small cell lung cancers. RESULTS: A-928605 is a selective IGF1R inhibitor that is able to abrogate activation of the pathway both in vitro and in vivo. This novel compound dosed as a single agent is able to produce significant growth inhibition of neuroblastoma xenografts in vivo. A-928605 is also able to provide additive effects when used in combination with clinically approved agents directed against EGFR in non-small cell lung and human pancreatic tumor models. CONCLUSION: These results suggest that a selective IGF1R inhibitor such as A-928605 may provide a useful clinical therapeutic for IGF pathway affected tumors and warrants further investigation
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