| 1. |
- Sadeghi, B., et al.
(författare)
-
GVHD after chemotherapy conditioning in allogeneic transplanted mice
- 2008
-
Ingår i: Bone Marrow Transplantation. - : Springer Science and Business Media LLC. - 0268-3369 .- 1476-5365. ; 42:12, s. 807-818
-
Tidskriftsartikel (refereegranskat)abstract
- GVHD is a major complication in allogeneic SCT. Available GVHD models are mainly based on radio-therapy-conditioning and/or immune deficient mice. GVHD models based on chemotherapy-based regimens remain poorly studied, despite 50% of all transplantations being chemotherapy based. Our aim was to develop a GVHD model using chemotherapy as conditioning. Female BALB/c (H-2Kd) were conditioned with BU-CY and transplanted with 2 x 10(7) BM and 3 x 10(7) spleen cells from either C57BL/6 (H-2Kb) mice ( allogeneic setting) or from male BALB/c to serve as a control group for regimen-related toxicity and engraftment. GVHD manifestations and histopathological changes were evaluated. Chimerism and donor T cells presence in skin, intestine and liver were studied using FACS-, FISH analysis and immunohistochemistry. Allogeneic transplanted mice developed lethal GVHD starting from day+7 with both histological and clinical signs. Donor T cells accumulated in recipient skin and intestine with GVHD progression. BM-failure, apoptosis and T-lymphocyte infiltration into target organs were significantly higher in allogeneic when compared with the syngeneic group. No toxicity or GVHD signs were observed in the syngeneic setting. We report a mouse model of GVHD using BU-CY conditioning that represents the most common myeloablative-conditioning regimen in clinical SCT. This model can be utilized to study the role of conditioning on mechanisms underlying GVHD.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Sadeghi, B., et al.
(författare)
-
The effect of administration order of BU and CY on engraftment and toxicity in HSCT mouse model
- 2008
-
Ingår i: Bone Marrow Transplantation. - : Springer Science and Business Media LLC. - 0268-3369 .- 1476-5365. ; 41:10, s. 895-904
-
Tidskriftsartikel (refereegranskat)abstract
- Conditioning regimens are an important issue determining the outcome of hematopoietic stem cell transplantation (HSCT). Less toxicity, early engraftment and no relapse are the aims of efficient conditioning. Our objective was to investigate the long-term effects of BU-CY and their administration order on the toxicity and chimerism in a mouse model of HSCT. Female BALB/c mice were treated with either BU (15 mg/kg/day x 4)-CY (100 mg/kg/day x 2) or CY-BU. Treated mice were transplanted with Sca-1+ cells from male BALB/c mice. Until 90 days after HSCT, the animals were monitored for body weight and analyzed for cellular phenotype of the thymus, spleen and BM, total chimerism, the spleen chimerism of DCs and T regulatory (Treg) cells, and hepatotoxicity. BU-CY and CY-BU treatments exerted comparable myeloablative and immunosuppressive effects. The long-term engraftment of donor cells in the BM and thymus regeneration showed the same features in both groups. However, the two regimens differed; in general, hepatotoxicity and chimerism of DC and Treg cells. In the long term, BU-CY, but not CY-BU caused a marked decrease in body weight and a significant increase in the activities of the liver enzymes, particularly aspartate amino transferase (AST). We conclude that the alteration of the administration order of BU-CY to CY-BU not only gives the same level of engraftment but also reduces the toxicity of the conditioning regimen that might be valuable specially in young patients who are undergoing HSCT.
|
|
| 5. |
|
|
| 6. |
- Carr, M., et al.
(författare)
-
Molecular phylogeny of choanoflagellates, the sister group to Metazoa
- 2008
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:43, s. 16641-16646
-
Tidskriftsartikel (refereegranskat)abstract
- Choanoflagellates are single-celled aquatic flagellates with a unique morphology consisting of a cell with a single flagellum surrounded by a "collar" of microvilli. They have long interested evolutionary biologists because of their striking resemblance to the collared cells (choanocytes) of sponges. Molecular phylogeny has confirmed a close relationship between choanoflagellates and Metazoa, and the first choanoflagellate genome sequence has recently been published. However, molecular phylogenetic studies within choanoflagellates are still extremely limited. Thus, little is known about choanoflagellate evolution or the exact nature of the relationship between choanoflagellates and Metazoa. We have sequenced four genes from a broad sampling of the morphological diversity of choanoflagellates including most species currently available in culture. Phylogenetic analyses of these sequences, alone and in combination, reject much of the traditional taxonomy of the group. The molecular data also strongly support choanoflagellate monophyly rejecting proposals that Metazoa were derived from a true choanoflagellate ancestor. Mapping of a complementary matrix of morphological and ecological traits onto the phylogeny allows a reinterpretation of choanoflagellate character evolution and predicts the nature of their last common ancestor.
|
|
| 7. |
- Freidovich, Leonid B, et al.
(författare)
-
Performance recovery of feedback-linearization-based designs
- 2008
-
Ingår i: IEEE Transactions on Automatic Control. - 0018-9286 .- 1558-2523. ; 53:10, s. 2324-2334
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a tracking problem for a partially feedback linearizable nonlinear system with stable zero dynamics. The system is uncertain and only the output is measured. We use an extended high-gain observer of dimension n+1, where n is the relative degree. The observer estimates n derivatives of the tracking error, of which the first (n-1) derivatives are states of the plant in the normal form and the $n$th derivative estimates the perturbation due to model uncertainty and disturbance. The controller cancels the perturbation estimate and implements a feedback control law, designed for the nominal linear model that would have been obtained by feedback linearization had all the nonlinearities been known and the signals been available. We prove that the closed-loop system under the observer-based controller recovers the performance of the nominal linear model as the observer gain becomes sufficiently high. Moreover, we prove that the controller has an integral action property in that it ensures regulation of the tracking error to zero in the presence of constant nonvanishing perturbation.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Jafri, Hassan, et al.
(författare)
-
Control of Conductivity in Graphene by Formation of Defects
- 2008
-
Ingår i: AVS 55th International Symposium & Exhibition 2008, October 19-24, Boston, USA.
-
Konferensbidrag (refereegranskat)abstract
- Due to their large surface areas, the conductivity of graphene and carbonnano-sheets depends strongly on their chemical environment. This is thebase for future environmental sensors containing graphene sheets. Here, abinitiocalculations propose a possibility of conductivity increase. In theexperiment, a 1-2 orders of magnitude increase of the conductivity isobserved experimentally on sub-nanometTe carbon nano-sheets by using anin-situ nano-manipulation set-up. The conductivity of the graphene sheetswas assessed from first-principle simulations. Insertion of defects in thegraphene sheets can lead to a strong increase of the conductivity of singlegraphene sheets. To study this result experimentally, we carried outconductivity measurements on sub-nanometre graphene nano-sheets that aredeposited on W -substrates by radio-frequency plasma-enhanced chemicalvapour deposition. This deposition process creates free-standingmicrometer-sized carbon nano-sheets with sub-nanometre thickness. Thesenano-sheets were exposed to an acid treatment. It has been shown recentlythat such acid treatment creates defects in these sheets. Using a nanomanipulatorinside a scanning electron microscope, we individuallycontacted the nano-sheets and measured their resistance as a function oftheir functionalization. From more than 1000 measurements we obtain a 1-2order of magnitude increase of conductivity in the functionalised carbonnano-sheets as compared to just water treated or untreated carbon nanosheets.This result corresponds well to the conductivity change obtainedfrom theory. This study makes it possible to create environmental sensorsbased on graphene like carbon nano-sheets.
|
|
