Authors:Irena Vovk, Nadja Gerčar, Breda Simonovska, and Mihael Sok
Cholesterol is an essential component of mammalian cells, but its role in cancer is unclear. We have determined the total cholesterol content in the healthy and the cancerous lung tissues of the same patient. Tissues of 13 patients (7 women and 6 men, different histological type, different stages of the disease) were obtained during surgical intervention. The samples (0.056–2.004 g) were hydrolyzed in alkaline medium, and the total cholesterol was extracted into n-hexane and simultaneously determined by thin-layer chromatography (TLC) on silica gel high-performance thin-layer chromatography (HPTLC) plates and nonaqueous reversed-phase high-performance liquid chromatography (HPLC), which both proved to be suitable for the determination of cholesterol in lung tissues and gave comparable results. This is the first report about the comparison of the total cholesterol content in the healthy and the cancerous tissue of the same patient. The difference in the results for the total cholesterol from both types of tissues was remarkable. For 13 patients, the mean contents and standard deviations determined by TLC were 4.01 ± 0.75 mg g−1 in the healthy lung tissue and 7.75 ± 1.93 mg g−1 in the cancerous lung tissue. Comparable results were obtained by HPLC analyses of the same samples: 3.91 ± 0.73 mg g−1 in the healthy and 6.95 ± 1.83 mg g−1 in the cancerous lung tissue. The range of total cholesterol content determined by TLC was between 3.20 mg g−1 and 5.83 mg g−1 in healthy lung tissues, and between 4.64 mg g−1 and 12.01 mg g−1 in lung cancer tissues, while the ranges obtained by HPLC were between 2.80 mg g−1 and 5.49 mg g−1 for healthy lung tissue, and between 4.38 mg g−1 and 11.24 mg g−1 for lung cancer tissue. The cancerous lung tissue of each of the thirteen patients contained higher amounts of total cholesterol compared to their healthy lung tissue. In 8 of the patients, the total cholesterol in the cancer tissue was more than 60% higher than in the healthy tissue; furthermore, in 5 patients, it was more than 100% higher.
Authors:Noufissa Zanati, Michael Mathews, Indika Perera, John Moran, Jean Boutros, Alan Riga, and Mekki Bayachou
The long-term goal of this investigation is to study the effects of increased cholesterol levels on the molecular activity
of membrane-bound enzymes such as nitric oxide synthase, that are critical in the functioning of the cardiovascular system.
In this particular investigation, we used differential scanning calorimetry (DSC) and dielectric thermal analysis (DETA) to
study the effect of added cholesterol on melting/recrystallization and dielectric behavior, respectively, of phosphatidylcholine
(PC) bilayered thin films. We also used electrochemical methods to investigate the effect of added cholesterol on the redox
behavior of the oxygenase domain of nitric oxide synthase as a probe embedded in the PC films. The results show that added
cholesterol in the PC films seems to depress the molecular dynamics as indicated by lowered current responses in the presence
of cholesterol as well as a slight increase of the transition temperature in the overall two-phase regime behavior observed
in PC–cholesterol films. These results are rationalized in the context of the general DSC and DETA behaviors of the PC–chol
Authors:Petra Jazbec, Andrej Šmidovnik, Mateja Puklavec, Mitja Križman, Jernej Šribar, Luka Milivojević, and Mirko Prošek
Coenzyme Q10, an essential factor of oxidative phosphorylation and an important antioxidant, is used as food additive in industrial production of poultry meat. In this study chickens were fed with water-soluble coenzyme Q10-β-cyclodextrin complex for 40 days and the distribution of CoQ10 and cholesterol in the chicken-breast cells was then measured. Cell fractions were analyzed by HPTLC and results were confirmed with a new HPLC-MS method. Both methods are suitable for quantitative evaluation, but HPTLC is particularly suitable for screening purposes. Validation revealed HPTLC is a reliable, sensitive, and flexible analytical tool in comparison with HPLC-MS, despite its inherently lower sensitivity and selectivity.
Authors:Paweł Zarzycki, Małgorzata Bartoszuk, and Aneta Radziwon
In this paper we describe a robust and sensitive detection procedure for cholesterol and selected bile acids (cholic acid, lithocholic acid, and taurodeoxycholic acid sodium salt) using the common derivatization reagent phosphomolybdic acid (PMA). Visualization conditions were studied and optimized for steroids separated on glass TLC and HPTLC plates coated with silica gel (K60WF
S) and octadecylsilane (RP-18W) stationary phases. Spot intensities on the plates were quantified after spraying with PMA in methanol (10%
) and heating at temperatures from 40 to 120°C for times ranging from 2 to 40 min. The best conditions for high signal intensity were determined by using 3D temperature (
)-analytical signal (
) maps generated from the raw experimental data. In contrast with the number of “universal procedures” described in the literature our study indicated that for robust and sensitive quantification of our components of interest heating should be performed at relatively low temperatures (below 100°C) and for heating times in excess of 10 min. Particularly robust and sensitive detection of steroids separated on glass plates coated with both stationary phases was observed for temperatures ranging between 50 and 80°C and heating for at least 20 min in a simple gravity convection oven.
Authors:Á. Kovács, R. Dulicsek, L. Varga, J. Szigeti, and Z. Herpai
): Determination of cholesterol oxides in dairy products. Effect of storage conditions. J. agric. Fd Chem. , 45 , 4318-4323.
Determination of cholesterol oxides in dairy products. Effect of storage conditions
Authors:E. Greiner, R. Újhelyi, E. Sólyom, L. Bíró, E. Mozsáry, A. Regölyi-Mérei, M. Antal, and A. Madarasi
Miettien, T. A. (1972): Lipid absorption, bile acids and cholesterol metabolism in patients with chronic liver disease. Gut , 13 , 682-689.
Lipid absorption, bile acids and cholesterol metabolism in patients with chronic liver