| 1. |
- Brynhildsen, Jan, 1962-, et al.
(författare)
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Attitudes among students and teachers on vertical integration between clinical medicine and basic science within a problem-based undergraduate medical curriculum
- 2002
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Ingår i: Medical teacher. - : Informa UK Limited. - 0142-159X .- 1466-187X. ; 24:3, s. 286-288
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Tidskriftsartikel (refereegranskat)abstract
- Important elements in the curriculum at the Faculty of Health Sciences in Link÷ping are vertical integration, i.e. integration between the clinical and basic science sections of the curriculum, and horizontal integration between different subject areas. Integration throughout the whole curriculum is time-consuming for both teachers and students and hard work is required for planning, organization and execution. The aim was to assess the importance of vertical and horizontal integration in an undergraduate medical curriculum, according to opinions among students and teachers. In a questionnaire 102 faculty teachers and 106 students were asked about the importance of 14 different components of the undergraduate medical curriculum including vertical and horizontal integration. They were asked to assign between one and six points to each component (6 points = extremely important for the quality of the curriculum, 1 point = unimportant). Students as well as teachers appreciated highly both forms of integration. Students scored horizontal integration slightly but significantly higher than the teachers (median 6 vs 5 points, p=0.009, Mann-Whitney U-test), whereas teachers scored vertical integration higher than students (6 vs 5, p=0.019, Mann-Whitney U-test). Both students and teachers considered horizontal and vertical integration to be highly important components of the undergraduate medical programme. We believe both kinds of integration support problem-based learning and stimulate deep and lifelong learning and suggest that integration should always be considered deeply when a new curriculum is planned for undergraduate medical education.
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| 2. |
- Dahle, L. O., et al.
(författare)
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Pros and cons of vertical integration between clinical medicine and basic science within a problem-based undergraduate medical curriculum : examples and experiences from Linköping, Sweden
- 2002
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Ingår i: Medical teacher. - : Taylor & Francis. - 0142-159X .- 1466-187X. ; 24:3, s. 280-285
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Tidskriftsartikel (refereegranskat)abstract
- Problem-based learning (PBL), combined with early patient contact, multiprofessional education and emphasis on development of communications skills, has become the basis for the medical curriculum at the Faculty of Health Sciences in Link ping (FHS), Sweden, which was started in 1986. Important elements in the curriculum are vertical integration, i.e. integration between the clinical and basic science parts of the curriculum and horizontal integration between different subject areas. This article discusses the importance of vertical integration in an undergraduate medical curriculum, according to experiences from the Faculty of Health Sciences in Link ping, and also give examples on how it has been implemented during the latest 15 years. Results and views put forward in published articles concerning vertical integration within undergraduate medical education are discussed in relation to the experiences in Link ping. Vertical integration between basic sciences and clinical medicine in a PBL setting has been found to stimulate profound rather than superficial learning, and thereby stimulates better understanding of important biomedical principles. Integration probably leads to better retention of knowledge and the ability to apply basic science principles in the appropriate clinical context. Integration throughout the whole curriculum entails a lot of time and work in respect of planning, organization and execution. The teachers have to be deeply involved and enthusiastic and have to cooperate over departmental borders, which may produce positive spin-off effects in teaching and research but also conflicts that have to be resolved. The authors believe vertical integration supports PBL and stimulates deep and lifelong learning.
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| 3. |
- Ekman, Anna-Karin, et al.
(författare)
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IL-17 and IL-22 Promote Keratinocyte Stemness in the Germinative Compartment in Psoriasis
- 2019
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Ingår i: Journal of Investigative Dermatology. - : ELSEVIER SCIENCE INC. - 0022-202X .- 1523-1747. ; 139:7, s. 1564-
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Tidskriftsartikel (refereegranskat)abstract
- Psoriasis is an inflammatory skin disorder characterized by the hyperproliferation of basal epidermal cells. It is regarded as T-cell mediated, but the role of keratinocytes (KCs) in the disease pathogenesis has reemerged, with genetic studies identifying KC-associated genes. We applied flow cytometry on KCs from lesional and nonlesional epidermis to characterize the phenotype in the germinative compartment in psoriasis, and we observed an overall increase in the stemness markers CD29 (2.4-fold), CD44 (2.9-fold), CD49f (2.8-fold), and p63 (1.4-fold). We found a reduced percentage of cells positive for the early differentiation marker cytokeratin 10 and a greater fraction of CD29(+) and involucrin thorn cells in the psoriasis KCs than in nonlesional KCs. The up-regulation of stemness markers was more pronounced in the K10(+) cells. Furthermore, the psoriasis cells were smaller, indicating increased proliferation. Treatment with IL-17 and IL-22 induced a similar expression pattern of an up-regulation of p63, CD44, and CD29 in normal KCs and increased the colony-forming efficiency and long-term proliferative capacity, reflecting increased stem cell-like characteristics in the KC population. These data suggest that IL-17 and IL-22 link the inflammatory response to the immature differentiation and epithelial regeneration by acting directly on KCs to promote cell stemness.
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| 4. |
- Gréen, Anna, 1973-
(författare)
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Histone H1 : Subtypes and phosphorylation in cell life and death
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The genetic information of a human diploid cell is contained within approximately 2 metres of linear DNA. The DNA molecules are compacted and organized in various ways to fit inside the cell nucleus. Various kinds of histones are involved in this compaction. One of these histones, histone H1 is the topic of the present thesis. In addition to its structural role, H1 histones have been implicated in various processes, for example gene regulation and inhibition of chromatin replication.H1 histones, also termed linker histones, are relatively conserved proteins, and the various subtypes seem to have different and important functions even though redundancy between the subtypes has been demonstrated. Despite the sequence conservation of H1 subtypes, two sequence variations were detected within the H1.2 and H1.4 subtypes using hydrophilic interaction liquid chromatographic separation of H1 proteins from K562 and Raji cell lines in Paper I in the present thesis. The variations were confirmed by genetic analysis, and the H1.2 sequence variation was also found in genomic DNA of normal blood donors, in an allele frequency of 6.8%. The H1.4 sequence variation was concluded to be Raji specific. The significance of H1 microsequence variants is unclear, since the physiological function of H1 histones remains to be established.H1 histones can be phosphorylated at multiple sites. Changes in H1 phosphorylation has been detected in apoptosis, the cell cycle, gene regulation, mitotic chromatin condensation and malignant transformation. Contradictory data have been obtained on H1 phosphorylation in apoptosis, and many results indicate that H1 dephosphorylation occurs during apoptosis. We and others hypothesized that cell cycle effects by the apoptosis inducers may have affected previous studies. In Paper II, the H1 phosphorylation pattern was investigated in early apoptosis in Jurkat cells, taking cell cycle effects into account. In receptor-mediated apoptosis, apoptosis occurs with a mainly preserved phosphorylation pattern, while Camptothecin induced apoptosis results in rapid dephosphorylation of H1 subtypes, demonstrating that H1 dephosphorylation is not a general event in apoptosis, but may occur upon apoptosis induction via the mitochondrial pathway. The dephosphorylation may also be a result of early cell cycle effects or signalling.Therefore, the H1 phosphorylation pattern in the cell cycle of normal activated T cells was investigated in Paper IV in this thesis. Some studies, which have been made using cancer cell lines from various species and cell synchronization, have indicated a sequential addition of phosphate groupsacross the cell cycle. Normal T cells and cell sorting by flow cytometry were used to circumvent side-effects from cell synchronization. The data demonstrate that a pattern with phosphorylated serines is established in late G1/early S phase, with some additional phosphorylation occurring during S, and further up-phosphorylation seems to occur during mitosis. Malignant transformation may lead to an altered G1 H1 phosphorylation pattern, as was demonstrated using sorted Jurkat T lymphoblastoid cells.During mitosis, certain H1 subtypes may be relocated to the cytoplasm. In Paper III, the location of histones H1.2, H1.3 and H1.5 during mitosis was investigated. Histone H1.3 was detected in cell nuclei in all mitotic stages, while H1.2 was detected in the nucleus during prophase and telophase, and primarily in the cytoplasm during metaphase and early anaphase. H1.5 was located mostly to chromatin during prophase and telophase, and to both chromatin and cytoplasm during metaphase and anaphase. Phosphorylated H1 was located in chromatin in prophase, and in both chromatin and cytoplasm during metaphase, anaphase and telophase, indicating that the mechanism for a possible H1 subtype relocation to the cytoplasm is phosphorylation.In conclusion, data obtained during this thesis work suggest that H1 histones and their phosphorylation may participate in the regulation of events in the cell cycle, such as S-phase progression and mitosis, possibly through altered interactions with chromatin, and/or by partial or complete removal of subtypes or phosphorylated variants from chromatin.
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| 5. |
- Gréen, Anna, 1943-, et al.
(författare)
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Histone H1 Dephosphorylation Is Not a General Feature in Early Apoptosis
- 2008
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Ingår i: Biochemistry. - : ACS Publications. - 0006-2960 .- 1520-4995. ; 47, s. 7539-7547
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Tidskriftsartikel (refereegranskat)abstract
- Histone H1 is a family of nucleosomal proteins that exist in a number of subtypes. These subtypes can be modified after translation in various ways, above all by phosphorylation. Increasing levels of H1 phosphorylation has been correlated with cell cycle progression, while both phosphorylation and dephosphorylation of histone H1 have been linked to the apoptotic process. Such conflicting results may depend on which various apoptosis-inducing agents cause apoptosis via different apoptotic pathways and often interfere with cell proliferation. Therefore, we investigated the relation between apoptosis and H1 phosphorylation in Jurkat cells after apoptosis induction via both the extrinsic and intrinsic pathways and by taking cell cycle effects into account. After apoptosis induction by anti-Fas, no significant dephosphorylation, as measured by capillary electrophoresis, or cell cycle-specific effects were detected. In contrast, H1 subtypes were rapidly dephosphorylated when apoptosis was induced by camptothecin. We conclude that histone H1 dephosphorylation is not connected to apoptosis in general but may be coupled to apoptosis by the intrinsic pathway or to concomitant growth inhibitory signaling.
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| 6. |
- Gréen, Anna, et al.
(författare)
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Histone H1 interphase phosphorylation becomes largely established in G(1) or early S phase and differs in G(1) between T-lymphoblastoid cells and normal T cells
- 2011
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Ingår i: Epigenetics & Chromatin. - : BioMed Central. - 1756-8935. ; 4:15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Histone H1 is an important constituent of chromatin, and is involved in regulation of its structure. During the cell cycle, chromatin becomes locally decondensed in S phase, highly condensed during metaphase, and again decondensed before re-entry into G(1). This has been connected to increasing phosphorylation of H1 histones through the cell cycle. However, many of these experiments have been performed using cell-synchronization techniques and cell cycle-arresting drugs. In this study, we investigated the H1 subtype composition and phosphorylation pattern in the cell cycle of normal human activated T cells and Jurkat T-lymphoblastoid cells by capillary electrophoresis after sorting of exponentially growing cells into G(1), S and G(2)/M populations. less thanbrgreater than less thanbrgreater thanResults: We found that the relative amount of H1.5 protein increased significantly after T-cell activation. Serine phosphorylation of H1 subtypes occurred to a large extent in late G(1) or early S phase in both activated T cells and Jurkat cells. Furthermore, our data confirm that the H1 molecules newly synthesized during S phase achieve a similar phosphorylation pattern to the previous ones. Jurkat cells had more extended H1.5 phosphorylation in G(1) compared with T cells, a difference that can be explained by faster cell growth and/or the presence of enhanced H1 kinase activity in G(1) in Jurkat cells. less thanbrgreater than less thanbrgreater thanConclusion: Our data are consistent with a model in which a major part of interphase H1 phosphorylation takes place in G(1) or early S phase. This implies that H1 serine phosphorylation may be coupled to changes in chromatin structure necessary for DNA replication. In addition, the increased H1 phosphorylation of malignant cells in G(1) may be affecting the G(1)/S transition control and enabling facilitated S-phase entry as a result of relaxed chromatin condensation. Furthermore, increased H1.5 expression may be coupled to the proliferative capacity of growth-stimulated T cells.
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| 7. |
- Gréen, Anna, 1973-, et al.
(författare)
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Histone H1 interphase phosphorylation pattern becomes largely established during G1/S transition in proliferating cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Histone H1 is an important constituent of chromatin, and is believed to be involved in regulation of chromatin structure. During the cell cycle, chromatin becomes locally decondensed in S phase, highly condensed during metaphase and again decondensed before re-entry into G1. This has been connected to increasing phosphorylation of H1 histones during the cell cycle. However, many of these experiments have been performed in non-human and human cancer cell lines, and by the use of cell synchronization techniques and cell cycle-arresting drugs. In this study, we have investigated the H1 subtype composition and phosphorylation pattern in the cell cycle. Exponentially growing normal human activated T cells and Jurkat lymphoblastoid cells were sorted by fluorescence activated cell sorting into G1, S and G2/M populations, without the use of cell cycle arresting drugs. We found that the H1.5 protein level increased after T-cell activation. Our data indicate that serine phosphorylation of H1 subtypes occurred to a large extent in late G1 phase or early S, while some additional serine phosphorylation took place during S, G2 and M phases. Furthermore, our data suggest that the newly synthesized H1 molecules during S phase also achieve a similar phosphorylation pattern as the previous ones. Jurkat cells showed more extended H1.5 phosphorylation in G1 compared with T cells, a difference that can be explained by faster cell growth and/or the presence of enhanced H1 kinase activity in G1 in Jurkat cells. In conclusion, our data is consistent with a model where a major part of interphase H1 serine phosphorylation takes place within a narrow time window during the G1/Stransition. This implies that H1 serine phosphorylation may be coupled to changes in chromatin structure necessary for DNA replication.
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| 8. |
- Gréen,, Anna, 1973-, et al.
(författare)
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Translocation of Histone H1 Subtypes Between Chromatin and Cytoplasm During Mitosis in Normal Human Fibroblasts
- 2010
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Ingår i: Cytometry Part A. - : John Wiley & Sons. - 1552-4922 .- 1552-4930. ; 77A:5, s. 478-484
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Tidskriftsartikel (refereegranskat)abstract
- Histone H1 is an important constituent of chromatin which undergoes major structural rearrangements during mitosis. However, the role of H1, multiple H1 subtypes and H1 phosphorylation is still unclear. In normal human fibroblasts, phosphorylated H1 was found located in nuclei during prophase and in both cytoplasm and condensed chromosomes during metaphase, anaphase and telophase as detected by immunocytochemistry. Moreover, we detected remarkable differences in the distribution of the histone H1 subtypes H1.2, H1.3 and H1.5 during mitosis. H1.2 was found in chromatin during prophase, and almost solely in the cytoplasm of metaphase and early anaphase cells. In late anaphase it appeared in both chromatin and cytoplasm, and again in chromatin during telophase. H1.5 distribution pattern resembled that of H1.2, but some H1.5 remained situated in chromatin during metaphase and early anaphase. H1.3 was detected in chromatin in all cell cycle phases. We propose therefore, that H1 subtype translocation during mitosis is controlled by phosphorylation, in combination with H1 subtype inherent affinity. We conclude that H1 subtypes, or their phosphorylated variants, may be signalling molecules in mitosis or that they leave chromatin in a regulated way to give access for chromatin condensing factors or transcriptional regulators during mitosis.
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| 9. |
- Klang Årstrand, Hanna
(författare)
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Phosphoproteomic analysis of Arabidopsis thaliana ribosomes
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ribosomes serve as the site of protein synthesis in all living cells. Ribosomes were discovered in 1955 by George E. Palade when he was studying the endoplasmic reticulum which is covered by ribosomes. He received the Nobel Prize in Physiology or Medicine in 1974 for this discovery. Ribosomes are large protein and rRNA complexes which are made up from one small and one large subunit that work together to translate mRNA into a protein chain. Eukaryotic translation is mainly controlled during the initiation, which involves protein phosphorylation. In plants there is a general increase of protein synthesis during the day in order to synthesize proteins needed for photosynthesis. Phosphorylation can alter protein function and localization and is reversibly added and removed by kinases and phosphatases, respectively.The aim of the studies in this thesis was to elucidate the phosphorylation status of ribosomal proteins in the Arabidopsis thaliana 80S ribosome. I have focused on comparing ribosomal protein phosphorylation between different conditions and sub cellular locations, namely day/night conditions and cytosol/nucleus location.By using Fe3+IMAC to enrich phosphorylated peptides from cytosolic ribosomes followed by mass spectrometric analysis eight serine residues in six ribosomal proteins were found to be phosphorylated. Among these was a novel phosphorylation site in 40S ribosomal protein S6 at Serine 231. By using quantification with stable isotope labeling and mass spectrometry this phosphorylated residue and three other ribosomal phosphopeptides were found to have increased phosphorylation levels during day as compared to night ranging from 2 to 4 times. This phosphorylation increase can in turn effect the modulation of the diurnal protein synthesis in Arabidopis thaliana.Ribosome biogenesis involves shuttling of proteins and ribosomal subunits between the cell nucleus and cytoplasm. By purifying ribosomal proteins from these two cellular compartments and enriching for phosphopeptides using TiO2 affinity chromatography combined with mass spectrometry I was able to analyze their phosphorylation status. This method identified 13 phosphopeptides derived from 11 ribosomal proteins as well as phosphopeptides from two ribosomal associated proteins. 40S ribosomal protein S2-3 was found phosphorylated only in the cytoplasmic samples while 60S ribosomal protein L13-1 and the two ribosomal associated proteins were found only in the nuclear enriched samples.
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| 10. |
- Kostova-Koleva, Nora N., et al.
(författare)
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Histone H5chromatin interactions in situ are strongly modulated by H5 C-terminal phosphorylation
- 2013
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Ingår i: Cytometry Part A. - : Wiley-Blackwell. - 1552-4922 .- 1552-4930. ; 83A:3, s. 273-279
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Tidskriftsartikel (refereegranskat)abstract
- We used linker histone-depleted normal human fibroblast nuclei as templates to study how phosphorylation affects histone H5 binding to chromatin in situ. Permeabilized cells were treated with 0.7 M NaCl to extract the native linker histones. Histone H5 was purified from chicken erythrocytes and phosphorylated in vitro by recombinant cdk5/p35 kinase. High performance capillary electrophoresis (HPCE) showed that the phosphorylated protein contained a mixture of multiply phosphorylated forms. Control experiments, using mass spectrometry, revealed that up to five SPXK motifs in the C terminus were phosphorylated, but also that about 10% of the protein contained one phosphoserine in the N-terminus. Reconstitution of H1-depleted fibroblast nuclei with nonphosphorylated or phosphorylated H5 was performed at physiological ionic strength. The bound H5 was then extracted using NaCl concentrations in the range of 0.15 to 0.7 M. The release of the H5 molecules was monitored by DAPI staining and image cytofluorometry. Our results show that H5 phosphorylation substantially reduced its affinity for chromatin in situ, which support previous observations indicating that C-terminal phosphorylation may be essential for the biological functions of linker histones.
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