## Electronic Theses and Dissertations

1994

Dissertation

Ph.D.

#### Department

Chemistry and Biochemistry

#### Keywords

Chemistry, Biochemistry.

CC BY-NC-ND 4.0

#### Abstract

The purpose of this dissertation was to investigate the genetics and cellular expression of human apolipoproteins. The genetics aspect was an investigation of the Hind III apolipoprotein B gene DNA polymorphism and its association with lipids and lipoprotein parameters in a selected Canadian Caucasian population with documented coronary artery disease, and a healthy control population. To carry out this project, a simple and rapid method for the purification of human DNA from whole blood was developed. Typical 260 nm/280 nm absorbance ratio and yield for DNA so purified were 1.84 and 24.5 $\mu$g/mL, respectively. Patients had significantly (p $<$ 0.05) higher levels of cholesterol, triglycerides, LDL-cholesterol, apolipoprotein B, and lower level of apoAI compared to the controls. Restriction fragment length polymorphism analysis detected 9 hybridizable fragments denoted as H1 to H9. The H1, H2, H3, and H7 alleles were polymorphic. The (H4-H9) genotype was detected in 69% of the control group while the (H1-H9) genotype was observed in 68% of the patients. In the second phase of the studies the effects of insulin and thyroid hormone on apolipoprotein B, E, and AI mRNA expression were investigated using hepatoma cell-line. Thyroid hormone increased apolipoprotein B mRNA levels by about 25-36% as determined by slot- and Northern-blot analysis of total cellular RNA. No change in the amount of apolipoprotein B mRNA, measured by either slot- or Northern-blot analysis of total RNA was found in insulin treated cells. Both insulin and thyroid hormone were found to have no significant effect on apoE mRNA levels. The levels of apolipoprotein AI mRNA were found to be decreased by thyroid hormone and increased by insulin by about 19% and 30% respectively. A competitive chemiluminescent immunoassay was also developed for the sensitive measurement of apolipoprotein B. The lower limit of detection was 2.17 $\mu$g/L (4.0 pmol/L). Comparison of the assay with an immunoturbidimetric assay gave a slope of 0.84, y-intercept at $-$0.94 and a correlation coefficient of 0.86. In summary, the observed mutations in apolipoprotein B gene may not affect the rate of apolipoprotein B synthesis, clearance or the affinity of low-density lipoprotein for structural elements on the arterial wall. Furthermore, thyroid hormone appears to regulate apolipoprotein B and AI transcription while insulin modulates only apoAI mRNA levels.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .O42. Source: Dissertation Abstracts International, Volume: 56-01, Section: B, page: 0223. Adviser: K. Adeli. Thesis (Ph.D.)--University of Windsor (Canada), 1994.

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