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- Hedlund, Anna, et al.
(författare)
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Gd2O3 nanoparticles in hematopoietic cells for MRI contrast enhancement
- 2011
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Ingår i: International journal of nano medicine. - Manchester, UK : Dove Medical Press Ltd. - 1178-2013. ; 6, s. 3233-3240
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Tidskriftsartikel (refereegranskat)abstract
- As the utility of magnetic resonance imaging (MRI) broadens, the importance of having specific and efficient contrast agents increases and in recent time there has been a huge development in the fields of molecular imaging and intracellular markers. Previous studies have shown that gadolinium oxide (Gd2O3) nanoparticles generate higher relaxivity than currently available Gd chelates: In addition, the Gd2O3 nanoparticles have promising properties for MRI cell tracking. The aim of the present work was to study cell labeling with Gd2O3 nanoparticles in hematopoietic cells and to improve techniques for monitoring hematopoietic stem cell migration by MRI. Particle uptake was studied in two cell lines: the hematopoietic progenitor cell line Ba/F3 and the monocytic cell line THP-1. Cells were incubated with Gd2O3 nanoparticles and it was investigated whether the transfection agent protamine sulfate increased the particle uptake. Treated cells were examined by electron microscopy and MRI, and analyzed for particle content by inductively coupled plasma sector field mass spectrometry. Results showed that particles were intracellular, however, sparsely in Ba/F3. The relaxation times were shortened with increasing particle concentration. Relaxivities, r1 and r2 at 1.5 T and 21°C, for Gd2O3 nanoparticles in different cell samples were 3.6–5.3 s-1 mM-1 and 9.6–17.2 s-1 mM-1, respectively. Protamine sulfate treatment increased the uptake in both Ba/F3 cells and THP-1 cells. However, the increased uptake did not increase the relaxation rate for THP-1 as for Ba/F3, probably due to aggregation and/or saturation effects. Viability of treated cells was not significantly decreased and thus, it was concluded that the use of Gd2O3 nanoparticles is suitable for this type of cell labeling by means of detecting and monitoring hematopoietic cells. In conclusion, Gd2O3 nanoparticles are a promising material to achieve positive intracellular MRI contrast; however, further particle development needs to be performed.
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| 2. |
- Hedlund, Anna, 1973-
(författare)
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MRI Contrast Enhancement and Cell Labeling using Gd2O3 Nanoparticles
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is an increasing interest for nanomaterials in bio-medical applications and in this work, nanoparticles of gadolinium oxide (Gd2O3 ) have been investigated as a novel contrast agent for magnetic resonance imaging (MRI). Relaxation properties have been studied in aqueous solutions as well as in cell culture medium and the nanoparticles have been explored as cell labeling agents. The fluorescent properties of the particles were used to visualize the internalization in cells and doped particles were investigated as a multimodal agent that could work as a fluorescent marker for microscopy and as a contrast enhancer for MRI. Fluorescent studies show that the Gd2O3 nanoparticles doped with 5% terbium have interesting fluorescent properties and that these particles could work as such multimodal contrast agent. Relaxivity measurements show that in aqueous solutions, there is a twofold increase in relaxivity for Gd2O3 compared to commercial agent Gd-DTPA. In cell culture medium as well as in cells, there is a clear T1 effect and an increase in signal intensity in T1-mapped images. The cellular uptake of Gd2O3 nanoparticles were increased with the use of transfection agent protamine sulfate. This work shows that Gd2O3 nanoparticles possess good relaxation properties that are retained in different biological environments. Gd2O3 particles are suitable as a T1 contrast agent, but seem also be adequate for T2 enhancement in forinstance cell labeling experiments.
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| 3. |
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| 4. |
- Sundler J, Annelie, 1973-, et al.
(författare)
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Student nurses' experiences of the clinical learning environment in relation to the organization of supervision : A questionnaire survey
- 2014
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Ingår i: Nurse Education Today. - : Churchill Livingstone. - 0260-6917 .- 1532-2793. ; 34:4, s. 661-666
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Tidskriftsartikel (refereegranskat)abstract
- Aim The aim was to investigate student nurses' experiences of the clinical learning environment in relation to how the supervision was organized. Background The clinical environment plays an essential part in student nurses' learning. Even though different models for supervision have been previously set forth, it has been stressed that there is a need both of further empirical studies on the role of preceptorship in undergraduate nursing education and of studies comparing different models. Method A cross-sectional study with comparative design was carried out with a mixed method approach. Data were collected from student nurses in the final term of the nursing programme at three universities in Sweden by means of a questionnaire. Results In general the students had positive experiences of the clinical learning environment with respect to pedagogical atmosphere, leadership style of the ward manager, premises of nursing, supervisory relationship, and role of the nurse preceptor and nurse teacher. However, there were significant differences in their ratings of the supervisory relationship (p < 0.001) and the pedagogical atmosphere (p 0.025) depending on how the supervision was organized. Students who had the same preceptor all the time were more satisfied with the supervisory relationship than were those who had different preceptors each day. Students' comments on the supervision confirmed the significance of the preceptor and the supervisory relationship. Conclusion The organization of the supervision was of significance with regard to the pedagogical atmosphere and the students' relation to preceptors. Students with the same preceptor throughout were more positive concerning the supervisory relationship and the pedagogical atmosphere.
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