| 1. |
- Hladik, Daniela, et al.
(författare)
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Combined Treatment with Low-Dose Ionizing Radiation and Ketamine Induces Adverse Changes in CA1 Neuronal Structure in Male Murine Hippocampi
- 2019
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:23
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Tidskriftsartikel (refereegranskat)abstract
- In children, ketamine sedation is often used during radiological procedures. Combined exposure of ketamine and radiation at doses that alone did not affect learning and memory induced permanent cognitive impairment in mice. The aim of this study was to elucidate the mechanism behind this adverse outcome. Neonatal male NMRI mice were administered ketamine (7.5 mg kg(-1)) and irradiated (whole-body, 100 mGy or 200 mGy, Cs-137) one hour after ketamine exposure on postnatal day 10. The control mice were injected with saline and sham-irradiated. The hippocampi were analyzed using label-free proteomics, immunoblotting, and Golgi staining of CA1 neurons six months after treatment. Mice co-exposed to ketamine and low-dose radiation showed alterations in hippocampal proteins related to neuronal shaping and synaptic plasticity. The expression of brain-derived neurotrophic factor, activity-regulated cytoskeleton-associated protein, and postsynaptic density protein 95 were significantly altered only after the combined treatment (100 mGy or 200 mGy combined with ketamine, respectively). Increased numbers of basal dendrites and branching were observed only after the co-exposure, thereby constituting a possible reason for the displayed alterations in behavior. These data suggest that the risk of radiation-induced neurotoxic effects in the pediatric population may be underestimated if based only on the radiation dose.
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| 2. |
- Kilpeläinen, Tuomas O, et al.
(författare)
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Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
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| 3. |
- Arvidsson, Jonathan, et al.
(författare)
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Arterial occlusion duration affects the cuff-induced hyperemic response in skeletal muscle BOLD perfusion imaging as shown in young healthy subjects
- 2023
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Ingår i: Magnetic Resonance Materials in Physics Biology and Medicine. - 1352-8661. ; 36:6, s. 897-910
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Tidskriftsartikel (refereegranskat)abstract
- Objective Dynamic BOLD MRI with cuff compression, inducing ischemia and post-occlusive hyperemia in skeletal mus-cle, has been pointed out as a potential diagnostic tool to assess peripheral limb perfusion. The objective was to explore the robustness of this technique and its sensitivity to the occlusion duration. Materials and methods BOLD images were acquired at 3 T in 14 healthy volunteers. T*2-imaging with 5-and 1.5-min occlu-sions were acquired and several semi-quantitative BOLD parameters were derived from ROI-based T*2-time curves. Differ-ences in parameters from the two different occlusion durations were evaluated in the gastrocnemius and soleus muscles using non-parametrical tests. Intra-and inter-scan repeatability were evaluated with coefficient of variation.Results Longer occlusion duration resulted in an increased hyperemic signal effect yielding significantly different values (p < 0.05) in gastrocnemius for all parameters describing the hyperemic response, and in soleus for two of these parameters. Specifically, 5-min occlusion yielded steeper hyperemic upslope in gastrocnemius (41.0%; p < 0.05) and soleus (59.7%; p = 0.03), shorter time to half peak in gastrocnemius (46.9%; p = 0.00008) and soleus (33.5%; p = 0.0003), and shorter time to peak in gastrocnemius (13.5%; p = 0.02). Coefficients of variation were lower than percentage differences that were found significant. Discussion Findings show that the occlusion duration indeed influences the hyperemic response and thus should play a part in future methodological developments.
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| 4. |
- Bakshi, Mayur V., et al.
(författare)
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Long-term effects of acute low-dose ionizing radiation on the neonatal mouse heart : a proteomic study
- 2013
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 52:4, s. 451-461
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies establish that children and young adults are especially susceptible to radiation-induced cardiovascular disease (CVD). The biological mechanisms behind the elevated CVD risk following exposure at young age remain unknown. The present study aims to elucidate the long-term effects of ionizing radiation by studying the murine cardiac proteome after exposure to low and moderate radiation doses. NMRI mice received single doses of total body Co-60 gamma-irradiation on postnatal day 10 and were sacrificed 7 months later. Changes in cardiac protein expression were quantified using isotope-coded protein label and tandem mass spectrometry. We identified 32, 31, 66, and 34 significantly deregulated proteins after doses of 0.02, 0.1, 0.5, and 1.0 Gy, respectively. The four doses shared 9 deregulated proteins. Bioinformatics analysis showed that most of the deregulated proteins belonged to a limited set of biological categories, including metabolic processes, inflammatory response, and cytoskeletal structure. The transcription factor peroxisome proliferator-activated receptor alpha was predicted as a common upstream regulator of several deregulated proteins. This study indicates that both adaptive and maladaptive responses to the initial radiation damage persist well into adulthood. It will contribute to the understanding of the long-term consequences of radiation-induced injury and developmental alterations in the neonatal heart.
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| 5. |
- Bakshi, Mayur V, et al.
(författare)
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Total body exposure to low-dose ionizing radiation induces long term alterations to the liver proteome of neonatally exposed mice
- 2015
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 14:1, s. 366-373
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Tidskriftsartikel (refereegranskat)abstract
- Tens of thousands of people are being exposed daily toenvironmental low-dose gamma radiation. Epidemiological data indicate thatsuch low radiation doses may negatively affect liver function and result in thedevelopment of liver disease. However, the biological mechanisms behindthese adverse effects are unknown. The aim of this study was to investigateradiation-induced damage in the liver after low radiation doses. Neonatal maleNMRI mice were exposed to total body irradiation on postnatal day 10 usingacute single doses ranging from 0.02 to 1.0 Gy. Early (1 day) and late (7months) changes in the liver proteome were tracked using isotope-codedprotein label technology and quantitative mass spectrometry. Our dataindicate that low and moderate radiation doses induce an immediateinhibition of the glycolysis pathway and pyruvate dehydrogenase availability inthe liver. Furthermore, they lead to significant long-term alterations in lipidmetabolism and increased liver inflammation accompanying inactivation of thetranscription factor peroxisome proliferator-activated receptor alpha. This study contributes to the understanding of the potentialrisk of liver damage in populations environmentally exposed to ionizing radiation.
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| 6. |
- Bergström, Petra, et al.
(författare)
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Herpes Simplex Virus 1 and 2 Infections during Differentiation of Human Cortical Neurons
- 2021
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Ingår i: Viruses-Basel. - : MDPI AG. - 1999-4915. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus 1 (HSV-1) and 2 (HSV-2) can infect the central nervous system (CNS) with dire consequences; in children and adults, HSV-1 may cause focal encephalitis, while HSV-2 causes meningitis. In neonates, both viruses can cause severe, disseminated CNS infections with high mortality rates. Here, we differentiated human induced pluripotent stem cells (iPSCs) towards cortical neurons for infection with clinical CNS strains of HSV-1 or HSV-2. Progenies from both viruses were produced at equal quantities in iPSCs, neuroprogenitors and cortical neurons. HSV-1 and HSV-2 decreased viability of neuroprogenitors by 36.0% and 57.6% (p < 0.0001), respectively, 48 h post-infection, while cortical neurons were resilient to infection by both viruses. However, in these functional neurons, both HSV-1 and HSV-2 decreased gene expression of two markers of synaptic activity, CAMK2B and ARC, and affected synaptic activity negatively in multielectrode array experiments. However, unaltered secretion levels of the neurodegeneration markers tau and NfL suggested intact axonal integrity. Viral replication of both viruses was found after six days, coinciding with 6-fold and 22-fold increase in gene expression of cellular RNA polymerase II by HSV-1 and HSV-2, respectively. Our results suggest a resilience of human cortical neurons relative to the replication of HSV-1 and HSV-2.
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| 7. |
- Chen, Zhishan, et al.
(författare)
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Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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| 8. |
- Eriksson, Stefanie
(författare)
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Development of Novel Diffusion NMR Methods : Preclinical Applications in Colloidal Model Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- NMR is a powerful non-invasive technique utilizing radiofrequency and gradient pulses to manipulate the spinsof atomic nuclei. In particular, diffusion NMR uses strong magnetic field gradients to label the positions of spins allowing for the measurement of translational motion of molecules in liquids. The average displacement of water molecules can give information on the pore microstructure in various materials including biological cells and tissues.The interpretation of conventional diffusion NMR signal can be ambiguous, as it contains effects from microstructure, size and orientation. In this work, the underlying microscopic structures are exposed with novel diffusion NMR methods. q-MAS is a pulse sequence for isotropic diffusion encoding, which in combination with conventional diffusion NMR can be used to quantify the microscopic anisotropy. The shape of the microscopic diffusion tensor can be revealed by varying the anisotropy of the diffusion encoding. The methods are demonstrated in lyotropic liquid crystals and yeast cell suspensions.Diffusion NMR can be used to measure exchange between intra- and extracellular compartments. This can give information on the water transport across biological cell membranes. A method for measuring exchange in yeast cells with different intra- and extracelllular T2 values is presented.
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| 9. |
- Eriksson, Stefanie, et al.
(författare)
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Isotropic diffusion weighting in PGSE NMR by magic-angle spinning of the q-vector.
- 2013
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Ingår i: Journal of Magnetic Resonance. - : Elsevier BV. - 1096-0856 .- 1090-7807. ; 226, s. 13-18
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Tidskriftsartikel (refereegranskat)abstract
- When PGSE NMR is applied to water in microheterogeneous materials such as liquid crystals, foodstuffs, porous rocks, and biological tissues, the signal attenuation is often multi-exponential, indicating the presence of pores having a range of sizes or anisotropic domains having a spread of orientations. Here we modify the standard PGSE experiment by introducing low-amplitude harmonically modulated gradients, which effectively make the q-vector perform magic-angle spinning (MAS) about an axis fixed in the laboratory frame. With this new technique, denoted q-MAS PGSE, the signal attenuation depends on the isotropic average of the local diffusion tensor. The capability of q-MAS PGSE to distinguish between pore size and domain orientation dispersion is demonstrated by experiments on a yeast cell suspension and a polydomain anisotropic liquid crystal. In the latter case, the broad distribution of apparent diffusivities observed with PGSE is narrowed to its isotropic average with q-MAS PGSE in a manner that is analogous to the narrowing of chemical shift anisotropy powder patterns using magic-angle sample spinning in solid-state NMR. The new q-MAS PGSE technique could be useful for resolving size/orientation ambiguities in the interpretation of PGSE data from, e.g., water confined within the axons of human brain tissue.
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| 10. |
- ERIKSSON, STEFANIE, et al.
(författare)
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NMR diffusion-encoding with axial symmetry and variable anisotropy: Distinguishing between prolate and oblate microscopic diffusion tensors with unknown orientation distribution
- 2015
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Ingår i: Journal of Chemical Physics. - : American Institute of Physics (AIP). - 0021-9606 .- 1089-7690. ; 142:10, s. 104201-
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a nuclear magnetic resonance method for quantifying the shape of axially symmetric microscopic diffusion tensors in terms of a new diffusion anisotropy metric, D-Delta, which has unique values for oblate, spherical, and prolate tensor shapes. The pulse sequence includes a series of equal-amplitude magnetic field gradient pulse pairs, the directions of which are tailored to give an axially symmetric diffusion-encoding tensor b with variable anisotropy b(Delta). Averaging of data acquired for a range of orientations of the symmetry axis of the tensor b renders the method insensitive to the orientation distribution function of the microscopic diffusion tensors. Proof-of-principle experiments are performed on water in polydomain lyotropic liquid crystals with geometries that give rise to microscopic diffusion tensors with oblate, spherical, and prolate shapes. The method could be useful for characterizing the geometry of fluid-filled compartments in porous solids, soft matter, and biological tissues. (C) 2015 Author(s).
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