| 1. |
- Tanvir, N. R., et al.
(författare)
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A γ-ray burst at a redshift of z~8.2
- 2009
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 461, s. 1254-1257
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Tidskriftsartikel (refereegranskat)abstract
- Long-duration γ-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z>20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-α emitting galaxy. Here we report that GRB090423 lies at a redshift of z~8.2, implying that massive stars were being produced and dying as GRBs ~630Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.
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| 2. |
- Hessle, Christina, 1965, et al.
(författare)
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Gram-positive and Gram-negative bacteria elicit different patterns of pro-inflammatory cytokines in human monocytes.
- 2005
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Ingår i: Cytokine. - : Elsevier BV. - 1043-4666. ; 30:6, s. 311-8
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Tidskriftsartikel (refereegranskat)abstract
- Pro-inflammatory cytokines secreted by tissue macrophages recruit polymorphonuclear leukocytes and evoke fever, cachexia and production of acute phase proteins. This study investigates whether Gram-positive and Gram-negative bacteria equally and efficiently trigger production of the pro-inflammatory cytokines IL-1 beta, IL-6, IL-8 and TNF-alpha in human monocytes. A range of aerobic and anaerobic Gram-positive and Gram-negative bacteria were killed by UV-light and added in different concentrations to human monocytes. Cytokines were measured in 24 h supernatants by ELISA. Gram-positive and Gram-negative bacteria were equally efficient inducers of IL-1 beta, but Gram-positive bacteria generated twice as much TNF-alpha as did Gram-negative bacteria (p<0.001 for 25 and 250 bacteria/cell). In contrast, Gram-negative bacteria induced at least twice as much IL-6 and IL-8 as did Gram-positive bacteria (p<0.001 for 2.5, 25 and 250 bacteria/cell). While the cytokine responses to LPS were similar to those induced by the corresponding amount of Gram-negative bacteria, the strong IL-1 beta and TNF-alpha responses to Gram-positive bacteria could not be induced by soluble peptidoglycan or lipotheicoic acid. The particular nature of the bacteria, thus seem to modify the response to Gram-positive bacterial components. The different cytokine profiles evoked by Gram-positive and Gram-negative bacteria might optimize clearance of bacteria that differ in cell wall structure.
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| 3. |
- Lundell, Anna-Carin, 1976, et al.
(författare)
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Increased levels of circulating soluble CD14 but not CD83 in infants are associated with early intestinal colonization with Staphylococcus aureus
- 2007
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Ingår i: Clin Exp Allergy. ; 37:1, s. 62-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Soluble forms of the monocyte marker CD14 and the mature dendritic cell marker CD83 are plasma proteins with immunoregulatory functions. The physiological stimulus for their production is unclear and their possible role in allergy development is unknown. METHODS: We measured the plasma levels of soluble CD14 (sCD14) and soluble CD83 (sCD83) in 64 Swedish children in relation to intestinal bacterial colonization pattern in a prospective birth cohort. Soluble CD14 and sCD83 levels were quantified by enzyme linked immunosorbent assay in plasma obtained at birth and at 4, 18 and 36 months of age. All major aerobic and anaerobic bacteria were quantified in faecal samples obtained regularly over the first 8 weeks of life. Clinical allergy and IgE levels were evaluated at 18 months of age. RESULTS: Soluble CD14 in plasma increased during the first 18 months of life while sCD83 peaked at 4 months of age. Children who were perinatally colonized with Staphylococcus aureus had significantly higher levels of sCD14 in plasma at 4 months of age relative to non-colonized children. The levels of sCD14 were unrelated to colonization with Escherichia coli, other enterobacteria, enterococci, clostridia, Bacteroides, bifidobacteria or lactobacilli. Further, children with food allergy by 18 months tended to have lower levels of sCD14 than healthy children. Plasma levels of sCD83 were not related to either bacterial colonization pattern or allergy development. CONCLUSIONS: Perinatal colonization with S. aureus may trigger the occurrence of sCD14 in plasma, which may influence development of the infantile immune system and risk of allergy development.
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| 4. |
- Nowrouzian, Forough, 1957, et al.
(författare)
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Phylogenetic group B2 Escherichia coli strains from the bowel microbiota of Pakistani infants carry few virulence genes and lack the capacity for long-term persistence.
- 2009
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Ingår i: Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. - : Elsevier BV. - 1469-0691. ; 15:5, s. 466-72
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli strains of phylogenetic group B2 obtained from Western human hosts are enriched in virulence-associated genes and have a superior capacity to persist in the colonic microbiota. Here, E . coli strains from 22 infants born in Pakistan whose rectal flora was sampled regularly over the first 6 months of life were examined. B2 strains did not carry the virulence-associated genes sfaD/E, papC, neuB or hlyA more often than strains of other phylogenetic groups. B2 origin was not associated with persistence in the bowel microbiota. As compared with B2 strains from Swedish infants, Pakistani B2 strains carried significantly less often the virulence genes fimH (p 0.04), papC (p 0.02), papG class III (p 0.01), sfaD/E (p < or =0.0001), neuB (p < or =0.0001), and hlyA (p 0.005), and also the high-pathogenicity island (p < or =0.0001). A minority of Pakistani B2 strains belonged to recognized uropathogenic O-groups, which are common among 'Western' B2 strains. Thus, extra-intestinal pathogenicity may be the foremost characteristic of B2 strains colonizing Western populations.
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| 5. |
- Sollerman, J., et al.
(författare)
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Supernova 2006aj and the associated X-Ray Flash 060218
- 2006
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 454, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the afterglow of the gamma-ray burst (GRB) of February 18, 2006. This is a nearby long GRB, with a very low peak energy, and is therefore classified as an X-ray Flash (XRF). XRF 060218 is clearly associated with a supernova - dubbed SN 2006aj. We present early spectra for SN 2006aj as well as optical lightcurves reaching out to 50 days past explosion. Our optical lightcurves define the rise times, the lightcurve shapes and the absolute magnitudes in the U, V and R bands, and we compare these data with data for other relevant supernovae. SN 2006aj evolved quite fast, somewhat similarly to SN 2002ap, but not as fast as SN 1994I. Our spectra show the evolution of the supernova over the peak, when the U-band portion of the spectrum rapidly fades due to extensive line blanketing. We compare to similar spectra of very energetic type Ic supernovae. Our first spectra are earlier than spectra for any other GRB-SN. The spectrum taken 12 days after burst in the rest frame is similar to somewhat later spectra of both SN 1998bw and SN 2003dh, implying a rapid early evolution. This is consistent with the fast lightcurve. From the narrow emission lines from the host galaxy we derive a redshift of z=0.0331±0.0007. This makes XRF 060218 the second closest gamma-ray burst detected. The flux of these emission lines indicate a high-excitation state, and a modest metallicity and star formation rate of the host galaxy.
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