Cholesterol Content and Fatty Acids Composition of Mangalitsa Pork Meat

The aim of this study was to examine variability in cholesterol content and fatty acid composition in musculuslongissimus (MLLT) of various genotypes of pigs. Out of 30 male castrated animals used in the trial, 20 were Mangalitsa pigs (Swallow Belly - SBM and White - WM) while 10 were of the Swedish Landrace breed – SL. The representative of pig meat breeds, SL had significantly less cholesterol in MLLT compared to SBM and WM pigs. The total monounsaturated fatty acids (MUFA) and unsaturated fatty acids (USFA) content was higher in SBM and WM than in SL pigs (p< 0.001).     

基于荧光光谱法的皮肤胆固醇快速无创检测技术

皮肤胆固醇含量可以作为评价动脉粥样硬化的重要指标之一,现有的皮肤胆固醇含量检测主要基于实验室活检进行,缺少快速无创的检测技术和装备。针对以皮肤胆固醇含量为评价指标的动脉粥样硬化的早期快速筛查需求,本文提出了基于荧光光谱法的皮肤胆固醇快速无创检测方法,研发了一种皮肤胆固醇无创检测系统。为了提高测量的准确性和稳定性,该系统对温度引起的检测试剂荧光效率的波动进行了修正。本文结合气相色谱法对测量结果的准确性进行了验证,并通过检测正常人群和动脉粥样硬化高风险人群的皮肤胆固醇含量,明确了该系统的临床应用价值。本文的研究结果表明,462~520 nm波段内的平均荧光强度与温度的相关系数为-0.995(p<0.0001),可据此建立温度校准曲线对由温度差异引起的荧光波动进行修正。校正后,系统测量的皮肤胆固醇含量与气相色谱测量值的相关性显著,相关系数为0.905(p<0.0001)。在动脉粥样硬化高风险人群的筛查实验中,动脉粥样硬化高风险人群和正常人群的皮肤胆固醇检测结果具有显著差异(P=0.0004)。与现有技术相比,基于荧光光谱法的皮肤胆固醇检测技术具有测量快速无创等优势,为大规模开展动脉粥样硬化的早期风险筛查提供了先进技术手段。     

The functional role of sphingomyelin in cell membranes

Sphingomyelins (SM) constitute an important class of phospholipids in the membranes of most eukaryotic cells. In mammalian tissues, SM usually constitute 2–15% of the total organ phospholipid, but certain tissues such as brain, peripheral nervous tissue and ocular lenses have even higher SM contents. Typical properties of SM include their low degree of unsaturation, an asymmetric molecular structure, and their extensive hydrogen‐bonding properties. These features are all very important for the structural role of SM in biological membranes. SM interact favorably with cholesterol (and other sterols) and there is an established co‐localization of SM and cholesterol in the plasma membranes of cells and at the surface of lipoprotein particles. Together they form SM/sterol‐rich domains that often are more ordered than the surrounding phase in biological membranes. The growing body of evidence regarding their favorable interaction with sterols indicates that the functional role of SM per se is largely related to being a regulator of cholesterol distribution within cellular membranes and cholesterol homeostasis in cells. Together with other sphingolipids, SM also have an important functional role as precursors of sphingolipid signaling molecules, extensively reviewed elsewhere and not to be discussed here in more detail.     

Gamma-irradiation of individual cholesterol oxidation products

Cholesterol and seven of its oxidation products in aqueous suspensions of multilamellar vesicles or sonicated aqueous suspensions were subjected individually to γ-radiation (10 KGy) at 0–4°C in air, N₂ or N₂O. All compounds underwent some changes under the influence of radiation. β-Epoxide (cholesterol 5β,6β-epoxide) and, to a much lesser extent, α-epoxide (cholesterol 5α,6α-epoxide) were converted in low yield to 6-ketocholestanol (5α-cholestan-3β-ol-6-one). 7β-Hydroxycholesterol (cholest-5-ene-3β,7β-diol) and, to a lesser extent, 7α-hydroxycholesterol (cholest-5-ene-3β,7α-diol) gave low yields of 7-ketocholestanol (5α-cholestan-3β-ol-7-one). The latter compound also was obtained by irradiation of 7-ketocholesterol (cholest-5-ene-3β-ol-7-one). 6-Ketocholestanol and 7-ketocholestanol are potential biomarkers for irradiated meat and poultry.     

Antibody labeling of cholesterol/ceramide ordered domains in cell membranes

A monoclonal antibody raised against mixed monolayers of 60:40 mol % cholesterol/C16-ceramide of known structure was used to label cholesterol/ceramide-rich domains in cell membranes. The antibody, Cer-Chol 405F specifically recognizes the mixed crystalline and homogeneous phase in monolayers, but it does not interact with either of the components separately. It interacts differently with mixed monolayers that contain ceramides of different acyl chain length. When used on cells, the antibody labeling is sensitive to changes in cholesterol and ceramide levels, as well as to over-expression of specific ceramides; this is in agreement with the results that were obtained on lipid monolayers. This represents a proof of concept of the applicability of a new approach to the structural characterization of lipid microdomains in cell membranes. The approach consists of raising antibodies that recognize specific structural organizations of lipids in artificial mixtures, characterizing the antibody/ordered domain complexes in vitro, and subsequently using them to detect the presence of the same (or similar) domains in cell membranes.     

Effect of Dietary Cholesterol and Fat on Cell Cholesterol Transfer to Postprandial Plasma in Hyperlipidemic Men

Postprandial chylomicrons are potent ultimate acceptors of cell membrane cholesterol and are believed to accelerate reverse cholesterol transport (RCT). We compared the effects of meals rich in polyunsaturated fat (PUFA) and either high (605 mg) or low (151 mg) in cholesterol and a meal rich in dairy fat (DF) in the form of cream on net in vitro transport of red blood cell (RBC) membrane cholesterol to 4 and 6 h postprandial plasma in eight normotriglyceridemic (NTG-H) and eight hypertriglyceridemic (HTG-H) men with mild to moderate hypercholesterolemia. In HTG-H men, cell cholesterol accumulation in 6-h postprandial plasma was significantly (P = 0.02) less after the PUFA-HC meal compared with the other meals. The significant (P < 0.001) increase in cell plus endogenous cholesterol accumulation in the triglyceride-rich lipoprotein (TRL) fraction of 4 h postprandial plasma incubated with RBC was significantly (P = 0.007) higher after the PUFA-HC meal compared with DF meal in HTG-H men. In NTG-H men, cholesterol accumulation in plasma and plasma lipoproteins in the presence and absence of RBC was not significantly affected by the type of meal ingested. These data suggest that addition of large amounts of cholesterol to a PUFA meal may impair diffusion-mediated transport of cell membrane cholesterol to postprandial plasma and that replacing DF with PUFA in a meal increases postprandial lipemia and may potentially increase cholesterol accumulation in atherogenic postprandial TRL in HTG-H men.     

Effects of storage conditions on lipid oxidation in infant formulas based on several protein sources

The time course of several lipid oxidation parameters in infant formulas was the main focus of this study. Infant formulas based on different protein sources (milk protein, isolated soy protein, and hydrolyzed milk protein) were stored at different temperatures (32 and 55°C) in sealed containers in air for 1 yr. Levels of thiobarbituric acid-reactive substances and 7-ketocholesterol, and losses of essential fatty acids and tocopherols were measured to monitor lipid oxidation. Tocopherol losses and 7-ketocholesterol concentrations were better lipid oxidation parameters than the others. Their concentration and losses depended on type of infant formula, storage temperature, and time.     

The morphology and composition of cholesterol,protein, and bilirubin deposits in dried human bile: Cathodoluminescence and backscattered electron imaging

This work is the first to deal with the application of color cathodoluminescence scanning electron microscopy (CCL SEM) and a novel version of combined imaging with backscattered electrons (CCL+BSE SEM) for the study of the composition of bile and its precipitation mechanisms. The present study demonstrates cholesterol, protein, and bilirubin distribution in deposits of normal and abnormal humanbile after solution evaporation to full dryness. Qualitative CCL SEM analysis showed that dried bile remnants include different proportions of the above components. Three types of deposits were observed: Arborescent crystals, typical cholesterol crystals, and amorphous bilirubin particles. The selection of crystalline or amorphous precipitate phases is determined by the dehydration/concentration process. The findings may explain key features in lithogenesis.     

胆固醇氧化酶发酵研究

对从土壤中筛选到的菌株ＤＧＣ－００７进行ＵＶ诱变,选育到菌株ＤＧＣ－０４８．对影响突变株产酶的条件进行了优化,初步确定了ＤＧＣ－０４８合适的产酶摇瓶培养基组成．在发酵温度为３０℃,培养基起始ｐＨ７．５～８．０的条件下,接种量１０％,发酵４８ｈ,产酶可达３５０μｍｏｌ／（ｍｉｎ·Ｌ）     

光化学合成维生素D

本文报道了维生素D的发现以及它们的光化学合成与进展。中国科学院理化技术研究所开发了一条从胆固醇合成 7 DHC的新路线,提出了一条光化学合成维生素D3 的创新技术路线,并已经转让实施。同时还提出一条光化学合成维生素D2 的创新技术路线。