The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.
If you have any questions or comments, please contact us.
Phenotypic consequences of ras oncogene expression were studied in cells conditionally transformed by T24 H-ras and a temperature-sensitive SV40 large T antigen (tsA58). Previous studies have demonstrated that transformation of REF52 cells by ras and SV40 large T antigen requires continuous T antigen expression. Thus, tsA58/T24 H-ras transformants ceased growing when transferred to a restrictive temperature for T antigen expression. Inhibition of cell growth was accompanied by massive accumulations of cholesterol esters, triglycerides and a third lipid species, identified as glycerol ethers on the basis of mobility on TLC. Cholesterol esters were derived from serum lipoproteins, and appeared to accumulate because LDL receptor expression and activity did not decline in growth arrested cells. Triglycerides and glycerol ethers were products of cell metabolism. The process lacked features characteristic of adipocyte differentiation, but may suggest mechanisms important in diseases, such as atherosclerosis, that involve abnormal accumulations of neutral lipids. Accumulating lipid species may also include metabolites induced by ras that accumulate in growth-arrested cells.
Plasma exchange (PE) is considered the most effective nonsurgical treatment modality for the reduction of low-density lipoprotein (LDL) in patients with familial hypercholesterolemia (FH). However, the concomitant reduction of high-density lipoprotein (HDL) and the necessity and cost of using blood products are major drawbacks of PE. We studied the effects of selective LDL reduction using monoclonal anti-LDL antibodies in an investigational immunoadsorption (IA) system. Results were compared with the effects of PE. During the study period, two homozygous FH patients with baseline cholesterol levels greater than 10.34 mmol/L (400 mg/dL) were treated sequentially for a combined total of 37 IA treatments and the results were compared with a total of 19 sequential PE treatments. The IA system consisted of on-line plasma processing over two columns of monoclonal anti-LDL antibodies in alternating cycles of column adsorption and regeneration. No replacement solution was needed. PE was performed with a centrifugal plasma separator using 5% albumin as replacement solution. Results showed that the reduction of lipids with IA was 43% +/- 0.9% for cholesterol, 51% +/- 1.0% for LDL, and 19% +/- 1.3% for HDL, resulting in a reduction in the LDL to HDL ratio of 41% +/- 1.7%. Compared with IA, percent reduction by PE was significantly greater (P less than 0.001) for all lipids, but was nonselective (cholesterol, 74% +/- 1.0%; LDL, 77% +/- 1.2%; HDL, 73% +/- 2.7%), and therefore the reduction of the LDL to HDL ratio was only 6% +/- 3.6%, which was significantly less than for IA (P less than 0.001). Pretreatment HDL concentration appeared to increase with repetitive IA treatment, but decreased back to prestudy levels with repetitive PE.(ABSTRACT TRUNCATED AT 250 WORDS)
Gas chromatographic/mass spectroscopic and chiral analysis showed the presence of enzymatically derived 8,9-, 11,12- and 14,15-EET in rat plasma (2.8:1:3.4 molar ratio, respectively; 10.2 +/- 0.4 ng total EET/ml plasma). Greater than 90% of the plasma EETs was esterified to the phospholipids of circulating lipoproteins. The lipoprotein fraction with the highest EET concentration was LDL (8.1 +/- 0.9 ng/mg of protein) followed by HDL and VLDL (3.5 +/- 0.1 and 1.9 +/- 0.3 ng/mg of protein, respectively). In light of the biological activities of the EETs, these results suggest a potential systemic function for the cytochrome P-450 epoxygenase.
This study assessed fasting plasma lipids and lipoproteins and postprandial plasma lipids in healthy male subjects fed liquid-formula diets containing 40% of total energy as long-chain (LCT, primarily C18:1 and C18:2), medium-chain (MCT, C8:0-C10:0), or mixed-chain (structured lipid, STL, mostly C8:0, C10:0, and C22:0) triglycerides for 6 d. None of the diets altered plasma cholesterol concentrations. HDL cholesterol was decreased 14% by the STL diet (P < 0.044) and 15% by the MCT diet (P < 0.004) but was unchanged by the LCT diet. Plasma triglycerides were elevated 42% by the MCT diet (P < 0.006), but were unaltered by either the STL or LCT diets. Neither the STL nor the MCT diets produced changes in fasting lipoprotein lipid composition; however, during the LCT diet, VLDLs became enriched in triglyceride and LDLs became enriched in cholesterol. Postprandial triglyceridemia was significantly greater after subjects consumed the LCT diet than it was after they consumed either the STL or MCT diets, which were similar. Short-term feeding of MCT and STL diets produces significant changes in lipid metabolism. An understanding of the long-term effects of these diets awaits further study.
In a study of 193 massively obese patients plasma lipoprotein concentrations were elevated in 94 patients and were within normal limits in 99 patients. Jejunoileal bypass, in addition to causing weight loss, lowered plasma lipids in both groups to normal or below normal levels.