This study aimed to investigate lipoprotein metabolism in male hamsters fed diets considered to be atherogenic in humans. Livers from adult male hamsters were selected to study aspects of apolipoprotein B metabolism. Isolated hepatocytes in suspension were compared with those maintained under tissue culture conditions. Liver slices were also prepared and compared with isolated suspended hepatocytes. Freshly prepared hepatocytes from the animals were incubated with radiolabelled precursors in suspension, or they were maintained under tissue culture conditions; liver slices were also investigated. The rates of total protein synthesis were of the same order in each of these systems, but protein secretion was impaired in liver slices, probably as a result of diffusion problems associated with the altered architecture of the sliced tissue. Albumin constituted 40 - 50% of the secreted proteins in each system. The rates of VLDL synthesis were increased in cells and slices prepared from animals previously fed sucrose- or fat-rich diets, but the secretion of VLDL was inhibited when diets contained unsaturated fat. The overall synthesis of apolipoprotein B was enhanced by fat-feeding; in the case of suspended hepatocytes, secretion of this protein was decreased when the preceding diet contained fats that were unsaturated; while in the case of liver slices, secretion was paradoxically enhanced. Apolipoprotein B was not degraded at significant rates in hepatocytes prepared from either control or fat-fed hamsters.

by Lo Man-har. / Thesis (M.Sc.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 56-63). / LIST OF FIGURES --- p.5 / LIST OF TABLES --- p.6 / ACKNOWLEDGEMENTS --- p.8 / SUMMARY --- p.9 / Chapter 1. --- INTRODUCTION --- p.11 / Chapter 1.1 --- Lipid metabolism --- p.11 / Chapter 1.1.1 --- Chylomicron --- p.12 / Chapter 1.1.2 --- Very low density lipoprotein --- p.12 / Chapter 1.1.3 --- Low density lipoprotein --- p.13 / Chapter 1.1.4 --- High density lipoprotein --- p.14 / Chapter 1.2 --- Apolipoprotein B --- p.14 / Chapter 1.3 --- Apolipoprotein B gene --- p.15 / Chapter 1.4 --- Genetic variations in human apo B gene and their associations with abnormal lipid metabolism --- p.16 / Chapter 1.4.1 --- Abetalipoproteinemia --- p.16 / Chapter 1.4.2 --- Hypobetalipoproteinemia --- p.17 / Chapter 1.4.3 --- Familial hypercholesterolemia (FH) --- p.17 / Chapter 1.5 --- Polymorphisms of apo B gene --- p.17 / Chapter 1.6 --- Methods for detection of polymorphisms --- p.19 / Chapter 2. --- OBJECTIVES --- p.20 / Chapter 3. --- MATERIALS AND METHODS --- p.21 / Chapter 3.1 --- Materials and equipments --- p.21 / Chapter 3.1.1 --- Enzymes --- p.21 / Chapter 3.1.2 --- DNA markers --- p.21 / Chapter 3.1.3 --- General reagents --- p.21 / Chapter 3.1.4 --- Equipments --- p.22 / Chapter 3.2 --- Buffers --- p.22 / Chapter 3.3 --- Agarose gel electrophoresis --- p.22 / Chapter 3.4 --- Study subjects --- p.23 / Chapter 3.4.1 --- Cord blood samples --- p.23 / Chapter 3.4.2 --- Geriatric subjects --- p.23 / Chapter - --- Cases --- p.23 / Chapter - --- Controls --- p.24 / Chapter 3.5 --- Clinical Data --- p.24 / Chapter 3.6 --- Blood collection --- p.24 / Chapter 3.7 --- Biochemical analysis --- p.25 / Chapter 3.8 --- DNA extractions --- p.25 / Chapter 3.9 --- Polymerase chain reaction (PCR) --- p.26 / Chapter - --- Oligonucleotide primers --- p.26 / Chapter - --- Signal peptide insertion/deletion polymorphism --- p.26 / Chapter - --- Xba I polymorphism --- p.27 / Chapter - --- Eco RI polymorphism --- p.28 / Chapter 3.10 --- Data analysis --- p.29 / Chapter 4. --- RESULTS --- p.30 / Chapter 4.1 --- Optimization of PCR --- p.30 / Chapter 4.2 --- Clinical features of the case and control subjects --- p.30 / Chapter 4.3 --- Genotyping --- p.31 / Chapter 5. --- DISCUSSION --- p.33 / Chapter 5.1 --- Optimization of PCR protocols --- p.33 / Chapter 5.2 --- Clinical data --- p.34 / Chapter 5.3 --- Allelic frequencies of the three polymorphisms of apo B gene --- p.35 / Chapter 5.4 --- Association of polymorphisms of apo B gene with the case group --- p.36 / Chapter 5.5 --- Association of polymorphisms of apo B gene with hyperlipidaemia --- p.36 / Chapter - --- Signal peptide insertion/deletion polymorphism --- p.36 / Chapter - --- Xba I polymorphism --- p.38 / Chapter - --- Eco RI polymorphism --- p.38 / Chapter 5.6 --- Conclusion --- p.39 / APPENDIX I --- p.53 / APPENDIX II --- p.54 / Chapter 6. --- REFERENCES --- p.56

LDL-receptor mutations and familial defective apolipoprotein B-100 (codon 3500) (FOB), the known causes of monogenic hypercholesterolemia (MH), have similar clinical features. The nature of the mutations responsible for MH in South Africans of Indian origin was previously unknown. Similarly, the mutations in the LDL-receptor gene of a South African Black FH homozygote had also not been characterised. The aim of this thesis was to identify and analyse the LDL-receptor mutations in the Indian homozygotes NS, D, AV and AA and in the Black homozygote JL. In addition, the possible importance of FOB as a cause of MH in South Africans was also assessed. The patient NS was characterized as having two "Null" LDL-receptor alleles. His skin fibroblasts expressed no detectable LDL-receptor protein and very low levels of LDL-receptor mRNA of approximately normal size. Since NS' s LDLreceptor promoter sequence was normal, his alleles are likely to harbour exonic point mutations or minor rearrangements that cause premature stop codons. The patient D was found to be a heteroallelic homozygote. Two new point mutations in the LDL receptor, Asp₆₉ -Tyr and Glu₁₁₉-Lys, were identified. D's fibroblasts expressed about 30% of the normal surf ace complement of receptors that bound LDL poorly. This low number could at least be partially explained by their decreased stability. These mutations were not identified in any other Indian FH or hypercholesterolemic patients. Patients AV and AA were both shown to be homoallelic homozygotes for the Pro₆₆₄ -Leu mutation. This mutation was identified in 4 unrelated Muslim families of Gujerati origin suggesting that the mutation arose from this area in India. Contrary to previous reports (Knight et al. 1990, Soutar et al. 1989), neither LOL nor β-VLDL binding were shown to be affected by this mutation. These mutant receptors were rapidly degraded. Thus the disease FH in these subjects is presumably due to the low steady-state level of mature receptors that are functionally normal but exhibit accelerated turnover. The Pedi FH homozygote, JL, expressed very few LOL receptors due to decreased receptor synthesis associated with low mRNA levels and not due to enhanced degradation. One of JL's LOL receptor alleles has a 3 b.p. deletion in repeat 1 of the promoter (G. Zuilani, H. Hobbs and L.F. de Waal, personal communication). The nature of the defect in his other allele is unknown. The importance of FOB as a cause of monogenic hypercholesterolemia in the South African Indian, "Coloured" and Afrikaner populations was determined by screening hypercholesterolemic subjects with or without xanthomata. The absence of FOB in such patients, in whom the relevant common or founder South African mutations were excluded, suggested that this disorder was rarer in these groups than in North America and Europe. FOB was identified in two different families of mixed British and Afrikaner ancestry. One family contained individuals who were heterozygous for the FOB mutation, as well as the FH Afrikaner-1 and the FH Afrikaner-2 LOL-receptor mutations. In addition, 4 compound heterozygotes, who had both FOB and the FH Afrikaner-1 mutation and one individual whu inherited all 3 defects, were identified. This family allowed us to characterise the compound heterozygotes with one mutant LOLreceptor allele and FOB as having a condition that was probably intermediate in severity between the FH heterozygote and homozygote states.

by Yuen Mei Ling, Miranda. / Thesis (M.Sc.)--Chinese University of Hong Kong, 1989. / Bibliography: leaves 73-83.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Thesis (Ph.D. in Molecular Biology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 123-140). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Diss. (sammanfattning) Göteborg : Univ. , 2009. / Härtill 3 uppsatser.