1.
Alvarado-Kristensson, Maria
(author)
Regulation of neutrophil apoptosis
2004
Doctoral thesis (other academic/artistic) abstract
The human neutrophil is the most abundant granulocyte and the major type of cell involved in an acute inflammatory response. Neutrophils are armed with various systems of enzymes, that can find and kill pathogens, but unfortunately, these "weapons" cannot distinguish between the host tissues and the "invaders." Therefore, an extensive neutrophil reaction leads to continuous release of toxic metabolites, which causes successive self-destruction of host tissues and possibly also organ failure. Such a series of destructive events has been implicated in diseases such as rheumatoid arthritis, myocardial infarction/reperfusion injury, atherogenesis, asthma, cystic fibrosis, emphysema, and vasculitis. Resolution of an acute inflammatory process depends on termination of neutrophil emigration from blood vessels and clearance of extravasated neutrophils and their metabolic products. Outside the blood vessels, neutrophils spontaneously undergo apoptosis, and are therefore removed by phagocytic cells at the site of inflammation. Neutrophil apoptosis can be modulated by several factors in the local environment, such as the Fas ligand (FasL), but the molecular mechanisms involved are poorly understood. In this dissertation thesis, I describe and elucidate intracellular signalling mechanisms that are involved in regulation of spontaneous and Fas-induced apoptosis in human neutrophils. Using two different methods it was possible to detect constitutive activity of p38 mitogen-activated protein kinase (p38) in newly isolated neutrophils. The p38 survival signal was transiently lost during both spontaneous and Fas-induced apoptosis, favoured induction of the apoptotic process. During the transient loss of p38 activity there was a temporary Fas-induced increase in phosphatidylinositol 3-kinase (PI3K) activity, which also had a pro-apoptotic impact on the neutrophils. In addition, my experiments showed that the active form of p38 associates with caspase 8 and caspase 3, which is necessary for p38-induced phosphorylation of serine-362 and serine-150 on these caspases. These biochemical modifications impair the activities, and possibly also the stability, of caspase 8 and 3 and thereby weaken the capacity of these enzymes to induce apoptosis. The results in this dissertation also demonstrate that the protein phosphatase type 2A (PP2A) can directly and independently decrease the phosphorylation levels of both p38 and caspase 3. Consequently, PP2A can increase the activity of caspase 3 by dual mechanisms and thereby promote the apoptotic response in human neutrophils.
2.
Bengtsson, Therese
(author)
Functional analysis of the alpha10beta1 integrin
2004
Doctoral thesis (other academic/artistic) abstract
The aim of this thesis was to study the function of the integrin a10b1. Integrins mediate signals between cells and their environment and regulate several cellular processes such as cell migration, proliferation and differentiation. The a10b1 integrin is expressed mainly by chondrocytes, the only cell type present in cartilage, and facilitates binding of the chondrocytes to the extracellular matrix molecule collagen. However, the function of the a10b1 integrin in cartilage is not known. In this thesis we describe the structure of the mouse a10b1 integrin gene and report the finding of two alternatively spliced extracellular forms of the a10b1 integrin. We also demonstrate the chromosomal localization of the human and mouse a10 integrin genes. To analyze the role of this collagen-binding integrin during development and in adult mice we generated a mouse deficient in the a10b1 integrin, by gene targeting deletion. We found that a10b1–null mice suffered from a mild chondrodysplasia, and that they had shorter limbs than normal mice. The mutant mice showed structural defects in the growth plate and decreased chondrocyte proliferation. Further studies have revealed that the a10b1 integrin appears to be the only collagen-binding integrin expressed in the growth plate of 8-week old mice. Together, these data show that the a10b1 integrin plays an important role in the regulation of chondrocyte function and bone development.
3.
Berglund, Mattias, 1972-
(author)
Molecular Characterization of Diffuse Large B-cell Lymphoma and Aspects of Transformation
2004
Doctoral thesis (other academic/artistic) abstract
Lymphomas are a heterogeneous group of neoplasias originating from B- or T-lymphocytes. In this thesis, we determined the genetic and immunophenotypic characterization of DLBCL and their prognostic impact. Moreover, genomic alterations associated with the transformation to DLBCL from Hodgkin lymphoma (HL) and follicular lymphoma (FL) were elucidated. In order to outline the impact of cytogenetic as well as immunophenotypic prognostic markers in DLBCL, we firstly studied a series of 54 DLBCL tumors using comparative genomic hybridization (CGH) and we identified several frequently occurring chromosomal imbalances. Loss of 22q was more often found in the diagnostic tumors with a more advanced clinical stage, while gain of 18q21 was more commonly identified in relapses. Secondly, we correlated the expression patterns of CD10, bcl-6, IRF-4 and bcl-2 with clinical parameters in a series of 173 de novo DLBCL patients. Patients with a germinal center (GC) phenotype displayed a better survival than the non-GC group. Expression of bcl-6 and CD10 was correlated with a better survival while bcl-2 expression was associated with a poor prognosis.In approaching the HL transformation, two novel B-cell lines (U-2932 and U-2940), derived from patients with DLBCL following HL, were characterized. Interestingly, a translocation with materials from 2q and 7q as well as loss of material on 6q was found in both cell lines. For FL transformation, we assessed chromosomal alterations in a panel of 28 DLBCL patients with a previous history of FL. The DLBCL tumors displayed more chromosomal imbalances compared to FL tumors. Loss of 6q16-21 and gain of 7pter-q22 were more commonly found in the DLBCL counterparts, suggesting the chromosomal location of putative genes that may be involved in the transformation process.
4.
5.
Engellau, Jacob
(author)
Prognostic factors in soft tissue sarcoma. Tissue microarray for immunostaining, the importance of whole-tumor sections and time-dependence.
2004
In: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 75:Suppl. 314, s. 5-5
Doctoral thesis (other academic/artistic) abstract
In adult soft tissue sarcoma (STS) of the extremities and trunk wall, improved prognostic factors are needed to identify patients at high-risk for metastasis. Various factors are included in the many prognostic systems currently in use and the prognostic value of immunohistochemical (IHC) expression of biological markers is unclear. The tissue-preserving, high throughput tissue microarray (TMA) technique for analysis of immunohistochemical expression of biological markers was validated for Ki-67, and was found to yield results comparable to conventional staining methods. TMA was used to study the IHC expression of multiple markers (Ki-67, p53, cyclin A, bcl-2, ß-catenin, CD44, and Pgp) in 218 malignant fi brous histiocytomas (MFH) and in 140 mixed STS. In the MFH series, tumor size and Ki-67, as the only IHC marker, provided independent prognostic information. In the mixed STS series whole-tumor sections were used and TMA was performed in the peripheral tumor growth zone. Whole-tumor sections facilitated assessment of the strong independent prognostic factors for metastasis vascular invasion, hazard ratio (HR) 3.5, tumor necrosis (HR 2.8), and tumor growth pattern (HR 3.2), and the latter also correlated with local recurrence (LR). In comparison, histological malignancy grade, tumor size, and depth were not of independent prognostic value. When TMA was performed from the peripheral tumor growth zone, the IHC expression of Ki-67 (HR 1.9), ß-catenin (HR 2.7), CD44 (HR 2.1) and Pgp (HR 2.4) were independent prognostic factors. Finally, prognostic factors were found to be time-dependent, and most factors lost their prognostic value after 2 years, whereas LR was a strong prognostic factor for metastasis whenever it occurred.
6.
Hansson, Anders
(author)
Transcriptional regulation and effects on differentiation by LMO proteins and the basic helix-loop-helix factors TAL1 and HEN1
2004
Doctoral thesis (other academic/artistic) abstract
Acute lymphoblastic leukemia (ALL) is the most widespread type of cancer, as well as the most frequent leukemia in children. Malignant ALL cells originate from normal T lymphocytes or B cells that are blocked at immature stages of differentiation. Since T cell lineage derived ALL in children is associated with various unfavorable features, it is no surprise that childhood T lineage ALL have been reported to have a worse prognosis than childhood B lineage ALL. However, the development of new diagnostic and therapeutic strategies have, in recent years improved the outcome for children with T cell ALL. Yet, the molecular basis of pathogenesis remains largely unknown. A number of transcription factors involved in normal blood cell development, have been shown to induce T cell malignancies when aberrantly expressed in T cells. However, the mechanisms by which these proteins contribute to tumorigenesis are essentially undefined. This study has focused on the normal and oncogenic pathways of two such transcription factors, termed LMO2 and TAL1, both crucial for normal blood development as well as implicated in the genesis of a subset of T cell leukemias. We have also investigated the functions of LMO2 and TAL1 related proteins. Here we show that the pTa and p16 genes are potential target genes for TAL1, indicating that TAL1 might interfere with both differentiation and cell cycle control. Thus, suggesting that TAL1 might possess dual tumorigenic qualities. Moreover, we demonstrate that LMO2 is involved in erythropoiesis.
7.
Herbertsson, Pär
(author)
Radial head and neck fractures
2004
Doctoral thesis (other academic/artistic) abstract
All elbow fractures between 1969 – 1979 (n=2965) registered at the radiographic archives at the Malmö University Hospital, where all radiographs are saved since a century, were evaluated. Fractures of the radial head and neck were classified according to the by Broberg and Morrey modified Mason classification. A Mason type I fracture is a less than 2 mm displaced fracture of the radial head or neck, a Mason type II fracture is a 2 mm or more displaced fracture, a Mason type III fracture is a comminuted fracture and a Mason type IV fracture is a radial head or neck fracture in addition with an elbow dislocation. Radial head or neck fractures were found in 756 individuals, in 480 (64%) a Mason type I fracture, in 222 (29%) a Mason type II fracture, in 36 (5%) a Mason type III fracture and in 18 (2%) a Mason type IV fracture. The annual incidence of radial head and neck fractures were 2.6 out of 10 000 in all individuals, 2.9 out of 10 000 in adults and 1.4 out of 10 000 in children. As to increase the sample size, when evaluating individuals with a Mason type IV fracture and individuals treated with an extirpation of the radial head, we included individuals found in the out- and in clinic registers and the operation registers during the years 1957 – 1990. All former patients, still living in Malmö, were after mean 11 – 46 years subjectively, objectively and radiographically re-evaluated. The 32 individuals with a displaced Mason type I fractures had all with conservative treatment predominantly a favourable outcome, no objective deficits, a higher prevalence of radiographic degenerative changes but no higher prevalence of elbow osteoarthritis (OA). The 22 children (below age 16) with a Mason type II or III fracture had a predominantly favourable outcome, an impaired flexion but no higher prevalence of radiographical degenerative changes or elbow OA, when a reduction of the fracture was undertaken if the fractured radial head was tilted more than 30 degrees. The 100 adults (16 years or older) with a Mason type II or III fracture had a predominantly acceptable outcome, an impaired flexion and extension, a higher prevalence of radiographic degenerative changes but no higher prevalence of elbow OA, if a late radial head excision was undertaken in cases with an unfavourable primary outcome. There were no differences in subjective, objective and radiographical outcome when comparing 43 individuals treated with a primary radial head excision with 18 individuals treated with a delayed radial head excision following a Mason type II – IV fracture. The 21 individuals with a Mason type IV fracture seemed to have a trend towards a higher proportion of unsatisfied individuals when compared with a Mason type I - III fracture. Although the majority still had an acceptable outcome, an impaired flexion and extension, a higher prevalence of radiographic degenerative changes but no higher prevalence of elbow OA, and none had experienced recurrent elbow dislocations.
8.
Kamp-Nielsen, Christian
(author)
Regulation and Function of the Human Leukotriene D4 Receptor CysLT1 in Epithelial Cells and Colon Cancer
2004
Doctoral thesis (other academic/artistic) abstract
The pro-inflammatory mediators leukotrienes have shown to be important players in the pathogenesis of diseases like asthma and inflammatory bowel disease (IBD). Patients suffering from IBD have been found to have an increased risk of developing colon cancer. Since leukotrienes have been shown in increased concentrations in stools of IBD patients we hypothesise that LTD4 can play a role in the development of colon cancer. In order to induce its effects on the intestinal epithelial cells, LTD4 binds to its receptor CysLT1R. We therefore chose to study CysLT1 in colon cancer specimens and in non-transformed and colon cancer cell lines. Our results show that CysLT1R can be found in increased levels in colon cancer enterocytes (50% of 84 patients) and that high expression of this receptor in Dukes`B staged tumours predicts a poor disease outcome. Furthermore, we observed that CysLT1R is located in the plasma membrane and in the outer nuclei membrane. We identified a putative nuclear localisation sequence in CysLT1R, which is crucial for the LTD4, induced internalisation of the receptor. Interestingly, stimulation of CysLT1R located in the nuclei induced the activation of ERK1/2, an enzyme which have been shown to mediate LTD4 induced proliferation. When studying the LTD4 induced signalling pathways we found that CysLT1R mediated stress fibre formation and a calcium response through two heterotrimeric G-proteins, Ga12 and Gai3, respectively and that the LTD4 induced calcium response is dependent on PKCe. Taken together we have shown that LTD4 might have an impact on tumour development through the regulation of CysLT1R and its downstream signalling pathways.
9.
Kraft, Maria
(author)
Regulation of Apoptosis in Hematopoietic Progenitor Cells: Involvement of Different Signaling Pathways
2004
Doctoral thesis (other academic/artistic) abstract
Proliferation, differentiation, and survival of hematopoietic stem cells and multipotent progenitor cells are regulated by cytokines and cell-cell interactions. Kit ligand (KL) and Flt3 ligand (FL) have pleiotropic effects, promotes survival, but are nonredundant. Using myeloid progenitor cell lines and mouse bone marrow-derived Lin- progenitors, we demonstrate that inhibition of phophatidylinositol (PI) 3-kinase abolish survival mediated by KL, whereas survival via FL is only partially affected. KL and FL both activate Akt, leading to inhibitory phosphorylation of the transcription factor FoxO3. Overexpression of constitutively active FoxO3, FoxO3(A3):ER, induced apoptosis even in the presence of KL or FL, indicating that inactivation of FoxO3 is crucial for signaling via both c-Kit and Flt3. Induction of FoxO3(A3):ER also inhibited myeloid and erythroid colony formation of Lin- progenitors. In addition FL, but not KL, induced expression of Bcl-2 and Bcl-xL. By overexpressing Akt and Bcl-2 we demonstrate that Bcl-2 is the better mediator of survival than Akt. However, Akt was crucial for KL-mediated survival since overexpression of dominant negative Akt induced apoptosis. We also conclude that Akt and Bcl-2 have synergistic effects since their coexpression was a far better mediator of survival than either one acting alone. In AML, Flt3 is commonly mutated via internal tandem duplications, rendering it constitutively active. Introducing Flt3-ITD into an IL-3 dependent progenitor cell line rendered it factor-independent. Both Akt and FoxO3 were phosphorylated in the absence of FL and several Bcl-2 family members were upregulated. In fact, Flt3-ITD activated additional Bcl-2 family members not activated by normal Flt3. Finally we found that PI3-kinase and an unidentified Src kinase were important for survival via Flt3-ITD. Signaling via normal Flt3 and Flt3-ITD differs in some aspects and disruption of specific Flt3-ITD signals may be potential targets for treatment.
10.
Olsson, Louise, 1960-
(author)
Early detection of colorectal cancer
2004
Doctoral thesis (other academic/artistic) abstract
This thesis addresses the early detection of colorectal cancer from several aspects. An audit of the diagnostic process was conducted in 227/235 (97%) patients with recentlydiagnosed colorectal cancer in the County of Västmanland, Sweden in 1998-99. The median work-up-time was 42 (QR 12-110) days for colon cancer and 23 (QR 0-49) days for rectal cancer. A family history was documented on the first visit in 2 /179 (1%) cases. For patients with right-sided cancer and a positive F-Hb, the median work-up time was 53 days while it was 448 days for patients with a negative result (p<0.01). The lack of ascertainment of family history as a means of risk assessment and the benefit of F-Hb in patients attending with symptoms could be questioned. The same cohort of patients was asked for a date on which the first symptoms appeared with an accuracy of two weeks. Emergency cases were excluded and the elective population was analysed separately. In this group, the median symptom duration was 20 weeks; 19 weeks for Dukes A and B and 21 weeks for Dukes C and D (p=0.8). Symptom duration did not influence overall survival either. Other public health strategies than a reduction in symptom duration have to be found. The risk of developing colorectal cancer is highly affected by genetic susceptibility. A family history was obtained from 400/411 (97%) eligible colorectal cancer patients in the County of Västmanland in 1998-2001. Five (1.2%) cases of HNPCC were identified. At least one first-degree relative with colorectal cancer was found in 47 (11.4%) patients. Every ninth patient with colorectal cancer thus represents a highly or intermediately increased risk of the disease among relatives. The low frequency makes the establishment of surveillance programs feasible. Mutations of the APC gene initiate the adeno-carcinoma sequence. As such, they are theoretically optimal markers for the early detection of colorectal cancer. Stool samples were collected from 28 patients with Dukes B cancer, 18 with adenomas of > 1 cm and 28 controls. A Digital Protein Truncation Test was applied and 17 / 28 (61%) cancer patients and 9 / 18 adenoma patients were identified. All the controls were negative. This suggests a new approach to screening for colorectal cancer. It is uncertain whether proximal cancer could also be detected using faecal DNA analysis. The BAT 26 tract is a marker of microsatellite instability, a characteristic trait of proximal cancer. Stool samples were collected from 46 patients with proximal cancer, 19 with proximal adenoma and 69 controls. Among cancer patients, 18 were found to have BAT 26 alterations in their tumours and 17 of them could be detected in stools. All the controls and adenoma patients were negative. The high specificity strengthens the prospect of DNA-based screening.
