No description available.

No description available.

This study was carried out to investigate the fatty acid composition of tumoral, marginal and normal breast tissue in female breast cancer patients. Patients were recruited from St. Boniface General Hospital. A pre-operative blood sample was drawn. After surgery, sections were obtained from tumoral, marginal and normal breast tissues for histology and biochemical analysis. Extracted lipids from marginal tissue were significantly higher than those in normal or tumoral tissue. The lipid profile in tumoral tissue was significantly different in terms of fatty acid composition compared to normal and marginal tissue with less linoleic and alpha linolenic acid and more long chain polyunsaturated fatty acid of omega-3 and omega-6 series. Marginal tissue showed significantly less alpha linolenic acid compared to normal tissue. An inverse correlation existed between plasma level of 22:6 n-3 and breast cancer stage. We found different lipid profile in tumoral tissue compared to normal and marginal tissue.

The tumour suppressor p53 has evolved a MDM2-dependent feedback loop that has a dual role as either a stimulator of p53 protein translation through mRNA binding or a stimulator of p53 protein degradation through the ubiquitin-proteasome system. A unique pseudo-substrate motif or “lid” in MDM2 is adjacent to its N-terminal hydrophobic drug-binding pocket and we have evaluated whether the lid of MDM2 is a physiological regulator of this dual function of MDM2. Deletion of this flexible pseudosubstrate motif inhibits MDM2 indicating that this peptide stretch can function as a positive regulatory motif. Phospho-mimetic mutation in the pseudo-substrate motif at codon 17 (MDM2S17D) stabilizes the binding of MDM2 towards p53. Molecular modeling orientates the pseudo-substrate motif over a charged surface patch on the MDM2 surface at Arg97/Lys98 and mutation of these residues to the MDM4 equivalent reverses the activating effect of the phosphomimetic mutation. Transient or inducible low level expression of MDM2WT can promote an increase in p53 protein steady-state levels whilst the expression of MDM2S17D in cells results in p53 protein de-stabilization. Phospho-specific antibodies to the MDM2 lid demonstrate two physiological conditions that alter lid phosphorylation: (i) lid hypo-phosphorylation occurs after DNA damage where p53 protein is stabilized and (ii) lid hyper-phosphorylation occurs at high cell density under conditions where p53 protein is de-stabilized. Expression of MDM2S17D in cells also de-stabilizes hyperubiquitinated mutant p53 under conditions where MDM2WT has no effect on mutant p53 protein degradation. The lid functions as a flexible regulatory motif whose phosphorylation switches MDM2 from a synthesis mode to a degradation mode with implications for defining the physiological signals that control the MDM2-p53 feedback regulatory loop.

No description available.

This study was carried out to investigate the fatty acid composition of tumoral, marginal and normal breast tissue in female breast cancer patients. Patients were recruited from St. Boniface General Hospital. A pre-operative blood sample was drawn. After surgery, sections were obtained from tumoral, marginal and normal breast tissues for histology and biochemical analysis. Extracted lipids from marginal tissue were significantly higher than those in normal or tumoral tissue. The lipid profile in tumoral tissue was significantly different in terms of fatty acid composition compared to normal and marginal tissue with less linoleic and alpha linolenic acid and more long chain polyunsaturated fatty acid of omega-3 and omega-6 series. Marginal tissue showed significantly less alpha linolenic acid compared to normal tissue. An inverse correlation existed between plasma level of 22:6 n-3 and breast cancer stage. We found different lipid profile in tumoral tissue compared to normal and marginal tissue.

It is becoming increasingly apparent that many of the genes in the class III region of the human Major Histocompatibility Complex encode proteins involved in the immune and inflammatory responses. Furthermore, genetic studies have indicated that genes within the class III region, particularly the telomeric segment containing the TNF gene, could contribute to susceptibility to diseases of immune-related aetiology. To further characterise this region and to identify candidate disease susceptibility genes, two overlapping cosmids, TN62 and TN82, covering an ~82kb segment of DNA around the TNF gene were selected for sequence analysis. The eight known genes in this region have been precisely positioned with the order: Gl/AIF-1, 1C7, LST1 (B144), LTB, TNF, LTA, IKBL, BAT1 (centromere to telomere) and their genomic structures have been defined. Comparison of the Gl genomic region with previously described cDNA and genomic sequences, together with the results of RT-PCR, indicates that three alternative transcripts, Gl, Allograft Inflammatory Factor-1 and Interferon-γ Responsive Transcript-1, are all derived from this gene. The completion of the sequence of 1C7 (D6S2570) has revealed that this gene encodes a putative novel member of the immunoglobulin superfamily. A number of alternatively spliced transcripts of 1C7 were identified by RT-PCR, all of which are expressed in immune-related cell lines. Alternative splicing within the immunoglobulin domain- encoding region was seen to result in possible set switching between an IgV domain and an IgC2 domain. In addition to this, a previously unidentified gene, homologous to a number of V- ATPase G-subunits, has been located 1kb telomeric of IKBL. Lastly, the pseudogene UCRH-L and an AIF-1 gene fragment have been identified in the intergenic region between AIF-1 and 1C7. In order to assess the contribution of loci in this region to disease susceptibility, the genes AIF-1, 1C7, ATP6G and the BAT1 promoter region were subjected to mutation analysis. A total of 28 polymorphisms have been identified, 8 in AIF-1, 10 in 1C7, 7 in ATP6G and 3 in the BAT1 promoter region. Work is at present underway to genotype a number of the identified polymorphisms in control DNAs and in DNA samples from patients with combined variable immunodeficiency (CVID). The information generated from this analysis will bring us closer to explaining the reported linkage of CVID with the telomeric end of the human MHC class III region.

No description available.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 115-129). / Microfiche. / ix, 129 leaves, bound ill. 29 cm

Multiple Endocrine Neoplasia Type I Syndrome (MEN 1) is a monogenic autosomal dominantly inherited cancer syndrome caused by a heterozygous loss of the MEN1 gene, predisposing for endocrine cell proliferation and tumor formation. MEN 1 carriers classically develop tumors in endocrine organs; the parathyroids, the endocrine pancreas, and the pituitary. Other organs, endocrine and non-endocrine, may also be affected. The most common cause of death in MEN 1 is pancreatic endocrine tumor (PNET), which exhibit inactivation of both MEN1 alleles. The increased proliferation prior to loss of the wild-type allele indicates haploinsufficiency, and little is known concerning the mechanisms behind MEN 1 PNET development. The MEN1 protein, menin, lacking homology with other known proteins, is involved in several aspects of transcriptional regulation and chromatin organization. We report differential expression and subcellular localization of transcription factors important in pancreatic development, in human and mouse MEN 1 pancreas, compared to non-MEN 1 pancreas. A predominantly cytoplasmic localization of Neurogenin3 and NeuroD1 was observed in tumors as well as in MEN 1 non-tumorous pancreas. Notch signaling factor expression and localization were examined in the pancreas of a heterozygous Men1 mouse model, and compared with that of wild-type littermates. Nuclear Hes1 was lost in tumors, concomitant to weaker Notch1 NICD expression, and further, analyzed using qPCR, it was shown that Notch1 was less expressed in heterozygous islets compared to wild-type islets. Performing a global gene expression array, we identified differential gene expression in five-week-old heterozygous Men1 mouse islets, compared to islets from wild-type littermates. The array results for a subset of the differentially regulated genes were corroborated using qPCR, western blotting and in situ PLA. We additionally observed significantly accelerated proliferation in islets from young heterozygous animals. It is often problematic to determine prognosis for individual patients with PNET. This is especially true in the group of patients with well differentiated endocrine carcinomas. In the absence of metastases, morphological signs of malignancy are frequently lacking. We evaluated the expression of nuclear and cytoplasmic survivin in a clinically characterized patient material (n=111), and a high nuclear survivin expression proved to be a significant negative prognostic factor for survival.