The hypothesis that elimination of facultative and strict anaerobic microorganisms from the gastro-intestinal tract by antimicrobial drugs in the period of time around allogeneic bone marrow ...transplantation (BMT) prevents acute graft-versus-host disease (GVHD), was examined in a cohort of 112 children grafted between 1989 and 2002 for hematological malignancies. All patients received T-cell replete marrow from human leukocyte antigens (HLA) matched sibling donors under identical transplantation conditions. To eliminate microorganisms from the gastro-intestinal tract, total gastro-intestinal decontamination (GID) was applied by high doses of non-absorbable antimicrobial drugs while the graft recipient was maintained in strict protective isolation. About half of the children (51%) proved to be successfully decontaminated, and about half (49%) unsuccessfully. One recipient got acute GVHD in the first group and 8 in the second group (p = 0.013). The degree of success of total GID was decisive for the occurrence of acute GVHD, irrespective of the presence of other risk factors such as higher age of recipient and/or donor, female donor for male recipient and carriership or reactivation of herpesviruses. Our results demonstrate that successful total GID of the graft recipient prevents moderate to severe acute GVHD. We suppose that substantial translocation of gastro-intestinal microorganisms or parts of these, functioning as microbial-associated molecular patterns (MAMP's), triggering macrophages/dendritic cells via pattern recognizing receptors (PRR's) is prohibited. As a consequence the initiation and progression of an inflammatory process leading to acute GVHD is inhibited.
We present new H - and K -band spectroscopy for the bulge of M31, taken with the LUCI spectrograph at the Large Binocular Telescope (LBT). We studied radial trends of CO absorption features (namely, ...CO1.58, CO1.60, CO1.64, CO1.66, CO1.68, CO2.30, CO2.32, and CO2.35) in the bulge of M31, out to a galactocentric distance of ∼100″ (∼380 pc). We find that most COs do not exhibit a strong radial gradient, despite the strong metallicity gradient inferred from the optical spectral range, except for CO1.64, showing a steep increase in the center. We compared the observed line strengths to predictions of different state-of-the-art stellar population models, including an updated version of EMILES models, which also uses the extended IRTF spectral library. The observed COs are close to models’ predictions, but in some models they turn out to be underestimated. We find that the lack of radial gradients is due to the combination of increasing CO strength with metallicity and C abundance, and decreasing CO strength with IMF slope and O abundance. We speculate that the steep gradient of CO1.64 might be due to Na overabundance. Remarkably, we were able to fit, at the same time, optical indices and all the NIR COs (except for CO1.68), leaving abundance ratios (i.e., C/Fe, O/Fe, and Mg/Fe) as free-fitting parameters, imposing age and metallicity constraints from the optical spectral range, with no significant contribution from intermediate-age populations (∼1 Gyr-old). For the majority of the bulge, we find Mg/Fe ∼ 0.15 dex, O/Fe larger than Mg/Fe (by ∼0.1 dex), and C abundance consistent with that of Mg. In the central (few arcsec) region, we still find an enhancement of O and Mg, but significantly lower C/Fe. We find that the COs’ line strengths of the bulge are significantly lower than those of massive galaxies, possibly because of a difference in carbon abundance, as well as, to some extent, total metallicity.
We present and discuss polarimetric observations of 182 targets drawn from an optically selected sample of 240 probable BL Lac candidates out of the SDSS compiled by Collinge et al. (2005, AJ, 129, ...2542). In contrast to most other BL Lac candidate samples extracted from the SDSS, its radio- and/or X-ray properties have not been taken into account for its derivation. Thus, because its selection is based on optical properties alone, it may be less prone to selection effects inherent in other samples derived at different frequencies, so it offers a unique opportunity to extract the first unbiased BL Lac luminosity function that is suitably large in size. We found 124 out of 182 targets (68%) to be polarized, 95 of the polarized targets (77%) to be highly polarized (>4%). The low-frequency peaked BL Lac candidates in the sample are on average only slightly more polarized than the high-frequency peaked ones. Compared to earlier studies, we found a high duty cycle in high polarization (\hbox{${\sim} 66^{+2}_{-14}\%$}~66-14+2% to be >4% polarized) in high-frequency peaked BL Lac candidates. This may come from our polarization analysis, which minimizes the contamination by host galaxy light. No evidence of radio-quiet BL Lac objects in the sample was found. Our observations show that the probable sample of BL Lac candidates of Collinge et al. (2005) indeed contains a large number of bona fide BL Lac objects. High S/N spectroscopy and deep X-ray observations are required to construct the first luminosity function of optically selected BL Lac objects and to test more stringently for any radio-quiet BL Lac objects in the sample.
Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. ...Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.
History of Graft-versus-Host Disease Vriesendorp, Huib M., MD, PhD; Heidt, Peter J., PhD
Experimental hematology,
08/2016, Letnik:
44, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Abstract Nuclear warfare at the end of World War II motivates Dick W. van Bekkum to study Total Body Irradiation (TBI) in animal models. After high dose TBI mice die from ‘primary disease’ or bone ...marrow aplasia. Intravenous administration of allogeneic bone marrow (BM) cells delays mortality, but does not prevent it. Initially the delayed deaths are said to be due to ‘secondary disease’ which is later renamed Graft-versus-Host Disease (GvHD). GvHD is caused by donor T-lymphocytes that destroy recipient cells in skin, intestinal mucosa, bile ducts and lymph nodes. GvHD is opposed by Host-versus-Graft Disease (HvGD): host T-lymphocytes destroying the administered allogeneic BM cells, including the administered T lymphocytes of the BM donor. In 1960 van Bekkum becomes the director of the Radiobiological Institute of the Dutch Organization for Applied Scientific Research TNO in Rijswijk, The Netherlands where he builds a multi-disciplinary team that defines the variables controlling the outcome of a BM transplant. The team publishes their early results in the Journal of Experimental Hematology 1, 2. Later, protocols for bone marrow transplantation in patients with Severe Combined Immunodeficiency Disease (SCID), leukemia, lymphoma and other diseases of the hemopoietic system are established. This review honors the scientific contributions made by Dick van Bekkum and his team in defining the four dominant variables for improving the therapeutic ratio of allogeneic BM transplantation and in fostering the international collaboration necessary to translate this knowledge into current clinical practice.
A 65-year-old male was admitted to the Intensive Care Unit after being resuscitated because of a hypoxic cardiac arrest caused by influenza. Blood cultures taken at time of admission surprisingly ...grew Bacillus mycoides, a spore-producing apathogenic agriculture bacterium. We collected culture samples at his barge. Although we did not culture Bacillus mycoides, we did find multiple other Bacillus species. We hypothesised that our patient was colonised from the freights of his barge, and bloodstream infection occurred during resuscitation with either the bacterium itself or its spores. To our knowledge, this is the first report on bloodstream infection with Bacillus mycoides in a human patient.
We report on ESO Very Large Telescope optical spectroscopy of 42 BL Lacertae objects of unknown redshift. Nuclear emission lines were observed in 12 objects, while for another six we detected ...absorption features due to the host galaxy. The new high signal-to-noise ratio spectra therefore allow us to measure the redshift of 18 sources. Five of the observed objects were reclassified as either stars or quasars, and one is of uncertain nature. For the remaining 18 the optical spectra appear without intrinsic features in spite of our ability to measure rather faint (equivalent width ~0.1 A) spectral lines. For the latter sources a lower limit to the redshift was set, exploiting the very fact that the absorption lines of the host galaxy are undetected in the observed spectra.
A sample of 40 bright spiral galaxies (${B_{\rm T}} < 12$) with low inclination and without bar was observed with JHK filters. For this purpose the MAGIC NICMOS3 camera at the 2.2 m telescope of the ...Calar Alto observatory, Spain was used. With a newly developed 2-dimensional algorithm the distribution of the surface brightness was fitted simultaneously by corresponding functions for the disk- and bulge-structure. While the disk was fitted with an exponential function, the bulge profile was fitted with a generalized de Vaucouleurs $R^{\beta}$ law, with the concentration parameter $\beta = 1/n$ as a further fit variable. The correlation of the resulting structural parameters of disks and bulges lead to some interesting relations: 1. The use of a variable exponent β is necessary for a realistic description of the bulge structure; 2. Disks and bulges show similar correlations between effective radius, effective surface brightness and luminosity; 3. They populate a common strip in the fundamental plane; 4. From the correlations between β and Hubble type some conclusions about the formation and evolution of spiral galaxies can be drawn.
Context. High redshift radio galaxies are among the most massive galaxies at their redshift, are often found at the center of protoclusters of galaxies, and are expected to evolve into the present ...day massive central cluster galaxies. Thus they are a useful tool to explore structure formation in the young Universe. Aims. 3C 294 is a powerful FR II type radio galaxy at z = 1.786. Past studies have identified a clumpy structure, possibly indicative of a merging system, as well as tentative evidence that 3C 294 hosts a dual active galactic nucleus (AGN). Due to its proximity to a bright star, it has been subject to various adaptive optics imaging studies. Methods. In order to distinguish between the various scenarios for 3C 294, we performed deep, high-resolution adaptive optics near-infrared imaging and optical spectroscopy of 3C 294 with the Large Binocular Telescope. Results. We resolve the 3C 294 system into three distinct components separated by a few tenths of an arcsecond on our images. One is compact, the other two are extended, and all appear to be non-stellar. The nature of each component is unclear. The two extended components could be a galaxy with an internal absorption feature, a galaxy merger, or two galaxies at different redshifts. We can now uniquely associate the radio source of 3C 294 with one of the extended components. Based on our spectroscopy, we determined a redshift of z = 1.784 ± 0.001, which is similar to the one previously cited. In addition we found a previously unreported emission line at λ6749.4 Å in our spectra. It is not clear that it originates from 3C 294. It could be the Ne IV doublet λ2424/2426 Å at z = 1.783, or belong to the compact component at a redshift of z ∼ 4.56. We thus cannot unambiguously determine whether 3C 294 hosts a dual AGN or a projected pair of AGNs.
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