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Search Results: 1 - 10 of 118739 matches for " Camilla T. Karlsson "
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Risk of Prostate Cancer after Trans Urethral Resection of BPH: A Cohort and Nested Case-Control Study
Camilla T. Karlsson,Fredrik Wiklund,Henrik Gr?nberg,Anders Bergh,Beatrice Melin
Cancers , 2011, DOI: 10.3390/cancers3044127
Abstract: Epidemiological and experimental evidence suggests that inflammation plays a role in both prostate cancer (PCa) and benign prostate hyperplasia (BPH). This study evaluates the risk of PC after transurethral resection (TURP) for BPH and estimates the PCa risk related to presence of inflammation in the resected material. The Pathology Department at the University Hospital of Ume? (Ume?, Sweden) identified BPH cases (n = 7,901) that underwent TURP between 1982 and 1997. Using these pathological specimens, we compared the incidence of PCa in the cohort to the population and calculated the standardized incidence and mortality ratios (SIR and SMR). Inflammation, the androgen receptor (AR), and p53 were evaluated in a nested case-control study of 201 cases and controls. Inflammation was graded severe or mild-moderate. In the follow-up period after TURP, cases developed prostate cancer and the controls did not. After TURP, SIR for prostate cancer increased [1.26, CI 95% (1.17–1.35)], whereas SMR decreased [0.59, CI 95% (0.47–0.73)]. Presence of inflammation at the time of TURP did not differ between cases and controls nor were there differences in p53 or AR staining. The data suggest a small increased risk of PCa after TURP and decreased PCa mortality. Inflammation at the time of TURP is not associated with PCa risk in this material. The increased PCa risk may be attributed to increased surveillance and PSA screening.
Articular cartilage stem cell signalling
Camilla Karlsson, Anders Lindahl
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2753
Abstract: Articular cartilage has been considered a post-mitotic tissue with virtually no cellular turnover. This has been based on the fact that the tissue is hypocellular and avascular and relies on diffusion for its nutrient supply. In the previous issue of Arthritis Research & Therapy, Grogan and colleagues [1] addressed the question of the localization of progenitor cells in healthy and osteoarthritic (OA) cartilage using Notch-1, Stro-1, and vascular cell adhesion molecule-1 (VCAM-1) as markers for stem cells.Articular cartilage has been proposed to consist of only terminally differentiated cells in adults, lacking progenitor cells – a dogma well-established in the textbooks. However, this dogma has been challenged in recent years [2-4] by the hypothesis that a progenitor cell population resides in the superficial zone of the cartilage. An additional challenge to the dogma is the fact that articular cartilage is not homogenous; instead, biochemical and morphological variations are seen from the surface zone (SZ) through the middle zone (MZ) and down to the deep zone (DZ). In the SZ, cells are flattened and secrete lubricin [5]; in the MZ, the cells are rounded and arranged in columnar structure and produce cartilage intermediate layer protein (CILP) [6]; but in the DZ, the cells are considerably larger and express type X collagen and alkaline phosphatase.Grogan and colleagues [1] related their finding to the three different zones in hyaline cartilage. The authors demonstrated similar staining patterns for the three makers but with a distinct zonal distribution pattern in healthy cartilage. The highest frequencies of stained cells were found in the SZ.The presence of progenitor cells is a key component to rapid and successful regeneration of a variety of tissues. The few studies performed concerning the regenerative potential of embryonic cartilage are somewhat conflicting. Namba and colleagues [7] reported that laceration of foetal cartilage has an intrinsic reparative
Chondrogenic differentiation potential of osteoarthritic chondrocytes and their possible use in matrix-associated autologous chondrocyte transplantation
Tilo Dehne, Camilla Karlsson, Jochen Ringe, Michael Sittinger, Anders Lindahl
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2800
Abstract: Articular chondrocytes from patients with OA undergoing total knee replacement (Mankin Score > 3, Ahlb?ck Score > 2) and from patients undergoing ACT, here referred to as normal donors (ND), were isolated applying protocols used for ACT. Their chondrogenic differentiation potential was evaluated both in high-density pellet and scaffold (Hyaff-11) cultures by histological proteoglycan assessment (Bern Score) and immunohistochemistry for collagen types I and II. Chondrocytes cultured in monolayer and scaffolds were subjected to gene expression profiling using genome-wide oligonucleotide microarrays. Expression data were verified by using real-time PCR.Chondrocytes from ND and OA donors demonstrated accumulation of comparable amounts of cartilage matrix components, including sulphated proteoglycans and collagen types I and II. The mRNA expression of cartilage markers (ACAN, COL2A1, COMP, CRTL1, SOX9) and genes involved in matrix synthesis (BGN, CILP2, COL9A2, COL11A1, TIMP4) was highly induced in 3D cultures of chondrocytes from both donor groups. Genes associated with hypertrophic or OA cartilage (ALPL, COL1A1, COL3A1, COL10A1, MMP13, POSTN, PTH1R, RUNX2) were not significantly regulated between the two groups of donors. The expression of 661 genes, including COMP, FN1, and SOX9, was differentially regulated between OA and ND chondrocytes cultured in monolayer. During scaffold culture, the differences diminished between the OA and ND chondrocytes, and only 184 genes were differentially regulated.Only few genes were differentially expressed between OA and ND chondrocytes in Hyaff-11 culture. The risk of differentiation into hypertrophic cartilage does not seem to be increased for OA chondrocytes. Our findings suggest that the chondrogenic capacity is not significantly affected by OA, and OA chondrocytes fulfill the requirements for matrix-associated ACT.The regenerative capacity of articular cartilage is very limited and injuries that do not penetrate the subchondral b
Chemical abundance patterns -- fingerprints of nucleosynthesis in the first stars
T. Karlsson,B. Gustafsson
Physics , 2001, DOI: 10.1051/0004-6361:20011217
Abstract: The interstellar medium of low-metallicity systems undergoing star formation will show chemical abundance inhomogeneities due to supernova events enriching the medium on a local scale. If the star formation time-scale is shorter than the time-scale of mixing of the interstellar matter, the inhomogeneities are reflected in the surface abundances of low-mass stars and thereby detailed information on the nucleosynthesis in the first generations of supernovae is preserved. Characteristic patterns and substructures are therefore expected to be found, apart from the large scatter behaviour, in the distributions of stars when displayed in diagrams relating different element abundance ratios. These patterns emerge from specific variations with progenitor stellar mass of the supernova yields and it is demonstrated that the patterns are insensitive to the initial mass function (IMF) even though the relative density of stars within the patterns may vary. An analytical theory of the formation of patterns is presented and it is shown that from a statistical point of view the abundance ratios can trace the different nucleosynthesis sites even when mixing of the interstellar medium occurs. Using these results, it should be possible to empirically determine supernova yields from the information on relative abundance ratios of a large, homogeneous sample of extremely metal-poor Galactic halo stars.
Uncertainty Bounds for Spectral Estimation
Johan Karlsson,Tryphon T. Georgiou
Mathematics , 2012,
Abstract: The purpose of this paper is to study metrics suitable for assessing uncertainty of power spectra when these are based on finite second-order statistics. The family of power spectra which is consistent with a given range of values for the estimated statistics represents the uncertainty set about the "true" power spectrum. Our aim is to quantify the size of this uncertainty set using suitable notions of distance, and in particular, to compute the diameter of the set since this represents an upper bound on the distance between any choice of a nominal element in the set and the "true" power spectrum. Since the uncertainty set may contain power spectra with lines and discontinuities, it is natural to quantify distances in the weak topology---the topology defined by continuity of moments. We provide examples of such weakly-continuous metrics and focus on particular metrics for which we can explicitly quantify spectral uncertainty. We then consider certain high resolution techniques which utilize filter-banks for pre-processing, and compute worst-case a priori uncertainty bounds solely on the basis of the filter dynamics. This allows the a priori tuning of the filter-banks for improved resolution over selected frequency bands.
Investigation of Chlamydiaceae in semen and cauda epididymidis and seroprevalence of Chlamydophila abortus in breeding bulls
Ann-Charlotte Karlsson, Stefan Alenius, Camilla Bj?rkman, Ylva Persson, Stina Englund
Acta Veterinaria Scandinavica , 2010, DOI: 10.1186/1751-0147-52-2
Abstract: Semen samples from 21 dairy bulls and cauda epididymidis tissue samples from 43 beef bulls were analysed for chlamydial agent by real-time polymerase chain reaction (PCR) including an internal amplification control (mimic). Additionally, presence of antibodies against Chlamydophila (Cp.) abortus among the bulls was investigated with the commercial Pourquier? ELISA Cp. abortus serum verification kit.No chlamydial agent was detected by PCR in either the semen samples or in the tissue samples. Additionally, no antibodies against Cp. abortus were detected.The results suggest that Cp. abortus is very rare, or absent in Swedish bulls and thus the risk for venereal transmission of chlamydial infection through their semen is low. However, because Chlamydophila spp. infection rates seem to differ throughout the world, it is essential to clarify the relative importance of transmission of the infection through semen on cattle fertility.Bovine chlamydiosis has been associated with several disease manifestations [1]. Reproductive disorders such as sporadic abortions and reduced fertility, linked with chlamydial infection have been reported from Germany [2,3], Great Britain [4], Italy [5], Japan [6], Switzerland [7], Taiwan [8] and the USA [9]. In Sweden, the incidence of abortion in cows is low. However, reproductive disorders and infertility are major causes of culling but are often difficult to be diagnosed. Chlamydial infection in bulls may be the cause to some of these problems [10]. Experimental studies have shown that the bacteria can be excreted in semen of inoculated bulls and rams [11] and isolation of the agent from semen of naturally infected bulls and rams has been reported [12-14]. The vaginal mucosa in sheep and uterine mucosa in cattle are susceptible to infection [15,16] and transmission of chlamydial agent by experimentally infected semen to heifers and sheep has been demonstrated [17,18].The two species Chlamydophila (Cp.) abortus and Cp. pecorum are known to i
Lrig2-Deficient Mice Are Protected against PDGFB-Induced Glioma
Veronica Rondahl, Camilla Holmlund, Terese Karlsson, Baofeng Wang, Mahmood Faraz, Roger Henriksson, H?kan Hedman
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073635
Abstract: Background The leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins constitute an integral membrane protein family that has three members: LRIG1, LRIG2, and LRIG3. LRIG1 negatively regulates growth factor signaling, but little is known regarding the functions of LRIG2 and LRIG3. In oligodendroglial brain tumors, high expression of LRIG2 correlates with poor patient survival. Lrig1 and Lrig3 knockout mice are viable, but there have been no reports on Lrig2-deficient mice to date. Methodology/Principal Findings Lrig2-deficient mice were generated by the ablation of Lrig2 exon 12 (Lrig2E12). The Lrig2E12-/- mice showed a transiently reduced growth rate and an increased spontaneous mortality rate; 20-25% of these mice died before 130 days of age, with the majority of the deaths occurring before 50 days. Ntv-a transgenic mice with different Lrig2 genotypes were transduced by intracranial injection with platelet-derived growth factor (PDGF) B-encoding replication-competent avian retrovirus (RCAS)-producing DF-1 cells. All injected Lrig2E12+/+ mice developed Lrig2 expressing oligodendroglial brain tumors of lower grade (82%) or glioblastoma-like tumors of higher grade (18%). Lrig2E12-/- mice, in contrast, only developed lower grade tumors (77%) or had no detectable tumors (23%). Lrig2E12-/- mouse embryonic fibroblasts (MEF) showed altered induction-kinetics of immediate-early genes Fos and Egr2 in response to PDGF-BB stimulation. However, Lrig2E12-/- MEFs showed no changes in Pdgfrα or Pdgfrβ levels or in levels of PDGF-BB-induced phosphorylation of Pdgfrα, Pdgfrβ, Akt, or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). Overexpression of LRIG1, but not of LRIG2, downregulated PDGFRα levels in HEK-293T cells. Conclusions The phenotype of Lrig2E12-/- mice showed that Lrig2 was a promoter of PDGFB-induced glioma, and Lrig2 appeared to have important molecular and developmental functions that were distinct from those of Lrig1 and Lrig3.
Investigation of subauroral ion drifts and related field-aligned currents and ionospheric Pedersen conductivity distribution
S. Figueiredo, T. Karlsson,G. T. Marklund
Annales Geophysicae (ANGEO) , 2004,
Abstract: Based on Astrid-2 satellite data, results are presented from a statistical study on subauroral ion drift (SAID) occurrence. SAID is a subauroral phenomenon characterized by a westward ionospheric ion drift with velocity greater than 1000m/s, or equivalently, by a poleward-directed electric field with intensity greater than 30mV/m. SAID events occur predominantly in the premidnight sector, with a maximum probability located within the 20:00 to 23:00 MLT sector, where the most rapid SAID events are also found. They are substorm related, and show first an increase in intensity and a decrease in latitudinal width during the expansion phase, followed by a weakening and widening of the SAID structures during the recovery phase. The potential drop across a SAID structure is seen to remain roughly constant during the recovery phase. The field-aligned current density and the height-integrated Pedersen conductivity distribution associated with the SAID events were calculated. The results reveal that the strongest SAID electric field peaks are associated with the lowest Pedersen conductivity minimum values. Clear modifications are seen in the ionospheric Pedersen conductivity distribution associated with the SAID structure as time evolves: the SAID peak is located on the poleward side of the corresponding region of reduced Pedersen conductivity; the shape of the regions of reduced conductivity is asymmetric, with a steeper poleward edge and a more rounded equatorward edge; the SAID structure becomes less intense and widens with evolution of the substorm recovery phase. From the analysis of the SAID occurrence relative to the mid-latitude trough position, SAID peaks are seen to occur relatively close to the corresponding mid-latitude trough minimum. Both these features show a similar response to magnetospheric disturbances, but on different time scales - with increasing magnetic activity, the SAID structure shows a faster movement towards lower latitudes than that of the mid-latitude trough. From the combined analysis of these results, we conclude that the SAID generation mechanism cannot be regarded either as a pure voltage generator or as a pure current generator, applied to the ionosphere. While the anti-correlation between the width and the peak intensity of the SAID structures with substorm evolution indicates a magnetospheric source acting as a constant voltage generator, the ionospheric modifications and, in particular the reduction in the conductivity for intense SAID structures, are indicative of a constant current system closing through the ionosphere. The ionospheric feedback mechanisms are seen to be of major importance for sustaining and regulating the SAID structures. Key words. Ionosphere (mid-latitude ionosphere; electric fields and currents; ionosphere-magnetosphere interactions) Full Article (PDF, 384 KB) Citation: Figueiredo, S., Karlsson, T., and Marklund, G. T.: Investigation of subauroral ion drifts and related field-aligned current
Green function theory of orbital magnetic moment of interacting electrons in solids
F. Aryasetiawan,K. Karlsson,T. Miyake
Physics , 2015,
Abstract: A general formula for the orbital magnetic moment of interacting electrons in solids is derived using the many-electron Green function method. The formula factorizes into two parts, a part that contains the information about the one-particle band structure of the system and a part that contains the effects of exchange and correlations carried by the Green function. The derived formula provides a convenient means of including the effects of exchange and correlations beyond the commonly used local density approximation of density functional theory.
Superrigidity, generalized harmonic maps and uniformly convex spaces
T. Gelander,A. Karlsson,G. A. Margulis
Mathematics , 2006,
Abstract: We prove several superrigidity results for isometric actions on metric spaces satisfying some convexity properties. First, we extend some recent theorems of N. Monod on uniform and certain non-uniform irreducible lattices in products of locally compact groups. Second, we include the proof of an unpublished result on commensurability superrigidity due to Margulis. The proofs rely on certain notions of harmonic maps and the study of their existence, uniqueness, and continuity.
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