| 1. |
- Brännvall, Karin, et al.
(author)
-
Central nervous system stem/progenitor cells form neurons and peripheral glia after transplantation to the dorsal root ganglion.
- 2006
-
In: NeuroReport. - 0959-4965 .- 1473-558X. ; 17:6, s. 623-628
-
Journal article (peer-reviewed)abstract
- We asked whether neural stem/progenitor cells from the cerebral cortex of E14.5 enhanced green fluorescent protein transgenic mice are able to survive grafting and differentiate in the adult rat dorsal root ganglion. Neurospheres were placed in lumbar dorsal root ganglion cavities after removal of the dorsal root ganglia. Alternatively, dissociated neurospheres were injected into intact dorsal root ganglia. Enhanced green fluorescent protein-positive cells in the dorsal root ganglion cavity were located in clusters and expressed beta-III-tubulin or glial fibrillary acidic protein after 1 month, whereas after 3 months, surviving grafted cells expressed only glial fibrillary acidic protein. In the intact adult DRG, transplanted neural stem/progenitor cells surrounded dorsal root ganglion cells and fibers, and expressed glial but not neuronal markers. These findings show that central nervous system stem/progenitor cells can survive and differentiate into neurons and peripheral glia after xenotransplantation to the adult dorsal root ganglion.
|
|
| 2. |
- Brännvall, Karin, et al.
(author)
-
Enhanced neuronal differentiation in a three-dimensional collagen-hyaluronan matrix
- 2007
-
In: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 85:10, s. 2138-2146
-
Journal article (peer-reviewed)abstract
- Efficient 3D cell systems for neuronal induction are needed for future use in tissue regeneration. In this study, we have characterized the ability of neural stem/progenitor cells (NS/PC) to survive, proliferate, and differentiate in a collagen type I-hyaluronan scaffold. Embryonic, postnatal, and adult NS/PC were seeded in the present 3D scaffold and cultured in medium containing epidermal growth factor and fibroblast growth factor-2, a condition that stimulates NS/PC proliferation. Progenitor cells from the embryonic brain had the highest proliferation rate, and adult cells the lowest, indicating a difference in mitogenic responsiveness. NS/PC from postnatal stages down-regulated nestin expression more rapidly than both embryonic and adult NS/PC, indicating a faster differentiation process. After 6 days of differentiation in the 3D scaffold, NS/PC from the postnatal brain had generated up to 70% neurons, compared with 14% in 2D. NS/PC from other ages gave rise to approximately the same proportion of neurons in 3D as in 2D (9-26% depending on the source for NS/PC). In the postnatal NS/PC cultures, the majority of III-tubulin-positive cells expressed glutamate, -aminobutyric acid, and synapsin I after 11 days of differentiation, indicating differentiation to mature neurons. Here we report that postnatal NS/PC survive, proliferate, and efficiently form synapsin I-positive neurons in a biocompatible hydrogel.
|
|
| 3. |
- Brännvall, Karin, et al.
(author)
-
Environmental cues from CNS, PNS, and ENS cells regulate CNS progenitor differentiation
- 2008
-
In: NeuroReport. - 0959-4965 .- 1473-558X. ; 19:13, s. 1283-9
-
Journal article (peer-reviewed)abstract
- Cellular origin and environmental cues regulate stem cell fate determination. Neuroepithelial stem cells form the central nervous system (CNS), whereas neural crest stem cells generate the peripheral (PNS) and enteric nervous system (ENS). CNS neural stem/progenitor cell (NSPC) fate determination was investigated in combination with dissociated cultures or conditioned media from CNS, PNS, or ENS. Cells or media from ENS or PNS cultures efficiently promoted NSPC differentiation into neurons, glia, and smooth muscle cells with a similar morphology as the feeder culture. Together with CNS cells or its conditioned medium, NSPC differentiation was partly inhibited and cells remained immature. Here, we demonstrate that secreted factors from the environment can influence CNS progenitor cells to choose a PNS-like cell fate.
|
|
| 4. |
- Erlandsson, Anna, et al.
(author)
-
Autocrine/Paracrine platelet-derived growth factor regulates proliferation of neural progenitor cells
- 2006
-
In: Cancer Research. - 0008-5472 .- 1538-7445. ; 66:16, s. 8042-8048
-
Journal article (peer-reviewed)abstract
- Growth factors play an important role in regulating neural stem cell proliferation and differentiation. This study shows that platelet-derived growth factor (PDGF) induces a partial differentiation of neural stem/progenitor cells (NSPCs) in the absence of other mitogens in vitro. NSPCs thus acquire an immature morphology and display markers for both neurons and glia. In addition, these cells do not readily mature in the absence of further stimuli. When NSPC cultures treated with PDGF were exposed to additional differentiation factors, however, the differentiation proceeded into neurons, astrocytes, and oligodendrocytes. We find that NSPC cultures are endowed with an endogenous PDGF-BB production. The PDGF-BB expression peaks during early differentiation and is present both in cell lysates and in conditioned medium, allowing for autocrine as well as paracrine signaling. When the NSPC-derived PDGF was inhibited, progenitor cell numbers decreased, showing that PDGF is involved in NSPC expansion. Addition of a PDGF receptor (PDGFR) inhibitor resulted in a more rapid differentiation. Neurons and oligodendrocytes appeared earlier and had more elaborate processes than in control cultures where endogenous PDGFR signaling was not blocked. Our observations point to PDGF as an inducer of partial differentiation of NSPC that also sustains progenitor cell division. Such an intermediate stage in stem cell differentiation is of relevance for the understanding of brain tumor development because autocrine PDGF stimulation is believed to drive malignant conversion of central nervous system progenitor cells.
|
|
| 5. |
- Larsson, Jimmy, et al.
(author)
-
Nuclear receptor binding protein 2 is induced during neural progenitor differentiation and affects cell survival
- 2008
-
In: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 39:1, s. 32-9
-
Journal article (peer-reviewed)abstract
- We previously identified nuclear receptor binding protein 2 (NRBP2) in a screen for genes induced by differentiation of neural stem/progenitor cells. Here we show that during embryonic mouse brain development NRBP2 was expressed in the walls of the third and fourth ventricles, and in the hippocampus. In the adult brain, Purkinje cells of the cerebellum and neurons in the CA3 region of the hippocampus were main sites of NRBP2 expression. Analysis of a pediatric medulloblastoma showed that clusters of NRBP2 positive tumor cells co-expressed neurofilament, but not GFAP. Thus, NRBP2 was associated with neuronal differentiation both in normal and malignant brain tissue. We report that NRBP2 is a 55-60 kDa protein with mainly cytoplasmic location. In vitro, NRBP2 protein levels increased as neural stem/progenitor cells differentiated, and its down regulation by siRNA rendered neural progenitor cells more vulnerable to apoptosis. NRBP2 has no previously assigned function and our studies suggest a role for NRBP2 in neural progenitor cell survival.
|
|
| 6. |
- Ossipov, Dmitri, et al.
(author)
-
Formation of the first injectable poly(vinyl alcohol) hydrogel by mixing of functional PVA precursors
- 2007
-
In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 106:1, s. 60-70
-
Journal article (peer-reviewed)abstract
- In this study we describe the development of an injectable, in situ chemical hydrogel forming system. The gelation occurs under neutral pH and at room temperature immediately upon mixing of the two aqueous poly (vinyl alcohol) components specifically derivatized through carbamate linkages with aldehyde (PVA-AL) and hydrazide (PVA-HY) functional groups, respectively. Aldehyde and hydrazide pendant groups were incorporated with a low degree of substitution (DS) into the PVA backbone to keep PVA structural homogeneity minimally altered. As a result, the hydrazone crosslinks are formed rapidly between aldehyde and hydrazide pendant groups when the correspondingly modified PVA components are brought in contact as water solutions. To assess in situ hydrazone crosslinks formation for in vitro cytocompatibility, murine neuroblastoma N2a cells were suspended in cell culture medium with the dissolved PVA-HY prior to addition to the PVA-AL aqueous solution. Thus, the cells were chemically encapsulated in a polymer network that was formed by mixing of the corresponding aqueous solutions of PVA functional precursors. Biochemical analysis revealed that cells survived chemical crosslinking and remained viable in the hydrogel for 4 days of culture.
|
|
| 7. |
- Wallenquist, Ulrika, 1975-, et al.
(author)
-
Grafted neural progenitors migrate and form neurons after experimental traumatic brain injury
- 2009
-
In: Restorative Neurology and Neuroscience. - Amsterdam : IOS Press. - 0922-6028 .- 1878-3627. ; 27:4, s. 323-334
-
Journal article (peer-reviewed)abstract
- PURPOSENeural stem and progenitor cells (NSPC) generate neurons and glia, a feature that makes them attractive for cell replacement therapies. However, efforts to transplant neural progenitors in animal models of brain injury typically result in high cell mortality and poor neuronal differentiation.METHODSIn an attempt to improve the outcome for grafted NSPC after controlled cortical impact we transplanted Enhanced Green Fluorescent Protein (EGFP)-positive NSPC into the contra lateral ventricle of mice one week after injury.RESULTSGrafted EGFP-NSPC readily migrated to the injured hemisphere where we analyzed the proportion of progenitors and differentiated progeny at different time points. Transplantation directly into the injured parenchyma, resulted in few brains with detectable EGFP-NSPC. On the contrary, in more than 90% of the mice that received a transplant into the lateral ventricle detectable EGFP-positive cells were found. The cells were integrated into the lateral ventricle wall of the un-injured hemisphere, throughout the corpus callosum, and in the cortical perilesional area. At one-week post transplantation, grafted cells that had migrated to the perilesion area mainly expressed markers of neural progenitors and neurons, while in the corpus callosum and the ventricular lining, grafted cells with a glial fate were more abundant. After 3 months, grafted cells in the perilesion area were less abundant whereas cells that had migrated to the walls of the third- and lateral- ventricle of the injured hemisphere were still detectable, suggesting that the injury site remained a hostile environment.CONCLUSIONTransplantation to the lateral ventricle, presumably for being a neurogenic region, provides a favorable environment improving the outcome for grafted NSPC both in term of their appearance at the cortical site of injury, and their acquisition of neural markers.
|
|
| 8. |
- Brännvall, Elisabet, 1961-, et al.
(author)
-
Process modifications to obtain a prehydrolysis kraft dissolving pulp with low limiting pulp viscosity
- 2020
-
In: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter. - 0283-2631 .- 2000-0669. ; 35:3, s. 332-341
-
Journal article (peer-reviewed)abstract
- Cellulose can be directly dissolved in cold alkali without derivatization. However, this requires low cellulose molecular weight, i. e. low pulp viscosity, preferably below 300 mL g−1. This can be achieved by for example acid or enzymatic hydrolysis of the dissolving pulp. However, it would be beneficial to manufacture pulp with sufficiently low viscosity without an additional treatment stage prior to dissolution. Unit processes in pulping can be operated in such a way as to reduce the molecular weight of cellulose. The approach of the study was to modify the conditions in unit pulping processes in order to obtain a low pulp viscosity of fully bleached prehydrolysis kraft pulp. A high charge of alkali in the oxygen delignification reduced the cellulose molecular weight significantly. Increased temperature, 120 °C compared to 98 °C, had also a significant effect on viscosity. By performing peroxide bleaching at acidic pH, the viscosity could be sufficiently reduced even when oxygen delignification was performed at lower temperature. However, for high brightness, a chlorine dioxide stage is needed.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
- Brännvall, Karin, 1974-
(author)
-
Hormonal Regulation of Neural Stem Cell Proliferation and Fate Determination
- 2004
-
Doctoral thesis (other academic/artistic)abstract
- Stem cells have the capacity for both self renewal, and to form all cell types in the body. Interestingly, so called neural stem cells (NSCs) are found in the adult human brain, which is of significance both out of a developmental perspective and from a clinical point of view. At the present moment, the regulation of neural stem cell (NSC) proliferation and fate determination is not completely understood.The overall aim of this thesis was to study the mechanisms that regulate NSC proliferation and fate determination in vitro and in vivo. In particular, the roles of the female sex hormone estrogen and the testosterone analogue nandrolone, as well as the melanocortin α-melanocyte stimulating hormone (α-MSH), were analyzed in this context. Also, the breast cancer susceptibility gene one (BRCA-1), was studied in the brain with emphasis on regions containing NSCs.Our findings show that estrogen and nandrolone have similar effects on NSCs; both decreased NSC proliferation and increased neurogenesis. Estrogen's ability to reduce proliferation was due to increased levels of p21, an inhibitor of cyclin dependent kinases. In contrast, no change in p21 was observed in the case of nandrolone, indicating differential regulation. Adult rats subjected to nandrolone injections had 30% reduced NSC proliferation in the dentate gyrus, indicating profound effects on NSCs in vivo.The melanocortin α-MSH acted as a mitogen by increasing levels of cyclinD1 and retinoblastoma protein; as a result NSC proliferation was doubled.Finally, BRCA-1 is expressed while NSCs proliferate, but is drastically down regulated upon differentiation, indicating that BRCA-1 could be used as a possible NSC marker.In summary, in this thesis estrogen and nandrolone were identified as NSC regulators which decrease proliferation and positively influence neurogenesis. Also, we have identified the hormone α-MSH as a NSC mitogen, and BRCA-1 as a possible NSC marker.
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Carlsson, Ninni, 1962, et al.
(author)
-
Forskare i könsrelaterat våld svarar David Eberhard : Okunskap i GP om #MeeToo och sexuella kränkningar
- 2017
-
In: Göteborgs-Posten, Ledarbloggen, 2017-11-20. - 1103-9345.
-
Journal article (pop. science, debate, etc.)abstract
- Syftet med denna artikel är att granska och problematisera en gästkrönika i Göteborgs-Posten den 6 november 2017, där psykologen David Eberhard kritiserar #metoo-rörelsen. Med exempel från lagstiftning och aktuell forskning diskuterar artikelförfattarna, sex forskare i könsrelaterat våld vid Institutionen för Socialt arbete, Göteborgs universitet, hur krönikan präglas av okunskap om sexuella kränkningar och tidigare kvinnorörelsers arbete; och hur den uttrycker en könsdiskriminerande och stigmatiserande attityd till dem som nu bryter tystnaden om egna erfarenheter. Artikeln är en replik till Eberhard som publicerades på Göteborgs-Postens ledarblogg den 20 november 2017.
|
|
| 20. |
- Korhonen, Laura, et al.
(author)
-
Hippocalcin protects against caspase-12-induced and age-dependent neuronal degeneration
- 2005
-
In: Molecular and Cellular Neuroscience. - Uppsala Univ, Ctr Biomed, Dept Neurosci, Neurobiol Unit, S-75123 Uppsala, Sweden. Uppsala Univ, Ctr Biomed, Dept Neurosci, Unit Physiol, S-75123 Uppsala, Sweden. Toho Univ, Sch Med, Dept Physiol, Ohta Ku, Tokyo 1438540, Japan. Minerva Med Res Inst, Biomedicum Helsinki, FIN-00290 Helsinki, Finland. : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1044-7431 .- 1095-9327. ; 28:1, s. 85-95
-
Journal article (peer-reviewed)abstract
- Hippocalcin is a neuronal calcium binding protein, but its physiological function in brain is unknown. We show here that hippocampal neurons from hippocalcin-deficient mice are more vulnerable to degeneration, particularly using thapsigargin, elevating intracellular calcium. Caspase-12 was activated in neurons lacking hippocalcin, while calpain was unchanged. Neuronal viability was accompanied by endoplasmic reticulum (ER) stress and a change in the relative induction of the ER chaperone, BiP/GRP78. Neuronal apoptosis inhibitor protein (NAIP), known to interact with hippocalcin, was not altered, but hippocampal neurons from gene-deleted mice were more sensitive to excitotoxicity caused by kainic acid. In addition, an age-dependent increase in neurodegeneration occurred in the gene-deleted mice, showing that hippocalcin contributes to neuronal viability during aging. (C) 2004 Elsevier Inc. All rights reserved.
|
|
| 21. |
- Zhao, Weifeng, 1987-
(author)
-
Chemical Pathways to Electrically Conductive Hemicellulose Hydrogels
- 2014
-
Licentiate thesis (other academic/artistic)abstract
- Hydrogels have been extensively explored and are widely used in diverse biomedical applications, such as scaffolds for tissue engineering and vehicles for drug delivery. As one type of important natural polymer-based hydrogel, hemicellulose hydrogels have interesting attributes, including being renewable, non-toxic, biocompatible, biodegradable, and abundantly available. A prominent way to extend their potential is by combining them with desirable properties from other materials. The focus of this thesis is to develop a new family of electrically conductive hemicellulose-based hydrogels (ECHHs) using O-acetyl-galactoglucomannan (AcGGM) and aniline oligomers through different chemical pathways.A first approach to synthesize the ECHHs includes two steps: first, carboxylated AcGGM (C-AcGGM) is dissolved with glycidyl methacrylate, followed by polymerization initiated by ammonium persulfate; second, the resulting hydrogels are covalently coupled to varying amounts of aniline tetramer (AT), which is homogeneously distributed throughout the network. The swelling ratios of C-AcGGM hydrogels decrease as the degree of substitution of maleic anhydride increases. The swelling ratios and conductivities of ECHHs are tuned by the AT content.To develop a simpler and greener approach to synthesize ECHHs under ambient conditions, AcGGM is in-situ cross-linked in the presence of aniline pentamer (AP) in basic water. Hydrogel equilibrium swelling ratios (ESRs) vary from 12.7 to 10.4, regulated by cross-linker concentration. The ESRs are also tuned from 9.6 to 6.0 by changing the AP contents from 10 % (w/w) to 40 % (w/w) while simultaneously altering conductivities from 9.05×10-9 to 1.58×10-6 S/cm.ECHHs with controllable conductivity, tunable swelling behavior and acceptable mechanical properties extend the applications of hemicellulose to include e.g. biosensors and electronic devices.
|
|
