| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Fish oil (n-3) polyunsaturated fatty acids beneficially affect biliary cholesterol nucleation time in obese women losing weight Mendez-Sanchez, N., V. Gonzalez, et al. (2001), J Nutr 131(9): 2300-3. Abstract: It has been reported that intake of (n-3) polyunsaturated fatty acids (PUFA) reduces the risk of coronary heart disease and decreases biliary cholesterol saturation in the bile of gallstone patients. We investigated the effect of n-3 PUFA on cholesterol saturation index (CSI) and nucleation time (NT) in obese subjects who were losing weight. This was a double-blind, placebo-controlled clinical trial. Obese women (n = 35) with a body mass index (BMI) > or = 30 kg/m(2), with no prior history of gallstones or cholecystectomy by ultrasound were first studied to ensure absence of stones or biliary sludge. The women were then assigned to a hypocaloric regimen 5.02 MJ (1200 kcal)/d and to receive 1200 mg/d of ursodeoxycholic acid (UDCA), 11.3 g/d of (n-3) PUFA or a placebo for 6 wk. BMI, CSI and NT were recorded at baseline and at the end of the experimental period. BMI decreased 5.75 +/- 2.7%/mo (range, 1.5-12.42%/mo) during the experiment. The CSI did not change in any of the groups. Cholesterol NT decreased significantly in the UDCA and placebo groups, but not in the (n-3) PUFA group. None of the women had developed gallstones at 6 wk. These results suggest that (n-3) PUFA maintain the CSI and NT in obese women during rapid weight loss, which probably results in the prevention of cholesterol gallstone formation. |
| Fish oil and oat bran in combination effectively lower plasma cholesterol in the rat Roach, P. D., K. Dowling, et al. (1992), Atherosclerosis 96(2-3): 219-26. Abstract: Male rats were fed a semi-purified diet containing oat bran or wheat bran with or without a marine fish oil to investigate the effects of such combinations on lipid metabolism. Oat bran alone and wheat bran plus fish oil gave lower plasma cholesterol concentrations than wheat bran alone while oat bran plus fish oil gave the lowest. Oat bran increased plasma triacylglycerols compared with wheat bran but oat bran plus fish oil gave concentrations similar to those seen with wheat bran plus fish oil. Oat bran gave higher hepatic cholesterol synthesis rates and a higher activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase compared to wheat bran. The addition of fish oil to either bran diet decreased cholesterol synthesis but HMG CoA reductase activity was not reduced. Oat bran increased hepatic acyl coenzyme A:cholesterol acyl transferase (ACAT) activity and increased the ratio of esterified to unesterified cholesterol in hepatic microsomal membranes compared with wheat bran. Fish oil decreased hepatic LDL receptor activity and increased HDL binding activity when added to the wheat bran diet but these effects were not seen with oat bran. Oat bran also had no effect on hepatic lipoprotein receptor activity compared with wheat bran. These results show that fish oil and oat bran have complementary cholesterol lowering effects in the rat. |
| Fish oil modifies effect of high cholesterol diet on intestinal absorption in diabetic rats Thomson, A. B., M. Keelan, et al. (1993), Diabetes Res 22(4): 171-83. Abstract: Omega-3 fatty acids ('fish oil') reduce the intestinal absorption of glucose and lipids in normal and in diabetic rats, but their effect is altered by the presence of saturated or poly-unsaturated omega-6 fatty acids in the diet. This study was undertaken to test the hypothesis that the influence of fish oil on the intestinal uptake of nutrients in diabetic rats is also influenced by the cholesterol content of the diet. Streptozotocin diabetic rats were raised for 2 wk on semisynthetic diets in which the lipid composition was derived mainly from beef tallow (BT), beef tallow plus cholesterol (BTC), fish oil (FO), or fish oil plus cholesterol (FOC). Food intake and weight gain was similar in the 4 diet groups, although the fasting blood glucose was lowest in diabetic rats fed BT. Cholesterol supplementation increased intestinal wall and mucosal weights when fed with BT, but the opposite effect was seen with FO, with lower wall and mucosal mass with FOC than with FO. Ileal uptake of D-glucose was lower in FO than in BT or FOC. Cholesterol feeding was associated with enhanced jejunal uptake of cholesterol when fed with BT, but the converse was observed with FO. Thus, 1) the reduction of glucose absorption associated with feeding fish oil is blunted in the presence of a supplemented intake of cholesterol; and 2) a fish oil diet reduces cholesterol uptake even in the presence of a high level of dietary cholesterol. It remains to be established what is the optimal ratio of dietary saturated, polyunsaturated omega-3 and omega-6 fatty acids, and cholesterol required to normalize intestinal transport function in diabetic rats. |
| Fish oil reduces cholesterol and arachidonic acid levels in plasma and lipoproteins from hypercholesterolemic chicks Castillo, M., F. Amalik, et al. (2000), Mol Cell Biochem 210(1-2): 121-30. Abstract: The value of fish oil for prevention and/or treatment of human atherosclerosis has not been fully established. This study shows that replacement of saturated fat in young chick diet with menhaden oil produced a significant reversion of the hypercholesterolemia previously induced by coconut oil feeding. Fish oil also produced a clear decrease of plasma triacylglycerol levels. Coconut oil increased the percentages of 12:0 and 14:0 fatty acids, while menhaden oil increased those of 20:5 n-3 and 22:6 n-3. Percentages of 20:4 n-6, 18:2 n-6 and 18:1 n-9 significantly decreased by fish oil addition to the diet. Total cholesterol, phospholipid and protein contents of high and low density lipoproteins increased by coconut oil feeding. When coconut oil was replaced by menhaden oil, total cholesterol was significantly reduced in high, low and very low density lipoproteins. All chemical components of VLDL were decreased by menhaden oil feeding. Our results show a strong hypocholesterolemic effect of menhaden oil when this fat was supplemented to hypercholesterolemic chicks. The clear decrease found in arachidonic acid content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids. |
| Fish oil supplementation and plasma cholesterol: the power of a clinical trial Szatrowski, T. P. (1990), Ann Intern Med 112(8): 633-4. |
| Fish oil supplementation attenuates free radical generation in short-term coronary occlusion-reperfusion in cholesterol-fed rabbits Chen, M. F., H. C. Hsu, et al. (1994), Prostaglandins 47(4): 307-17. Abstract: We studied the changes in lipid peroxidation and prostanoid metabolism in short-term coronary occlusion-reperfusion in controls and those rabbits (11 in each group) fed a 1% high cholesterol diet with or without 10% fish oil supplementation for one week. Acute coronary occlusion for 10 minutes was induced by ligating the marginal branch of the left circumflex coronary artery. The vessels were then reperfused for 1 hour. The cholesterol and fish oil treated rabbits had the lowest malondialdehyde levels both in the ischemic and non-ischemic (normal) areas, the least increase of malondialdehyde level in the ischemic area, and the highest 6-keto-PGF1 alpha/thromboxane B2 ratio in the non-ischemic area after reperfusion among the 3 groups. These rabbits had the highest myocardial superoxide dismutase levels both in the ischemic and normal areas, and the least decrease of superoxide dismutase level in the ischemic area. These data suggest that rabbits fed a high cholesterol diet with fish oil supplementation had an attenuated lipid peroxidation, which reflected a reduced free radical generation during a short-term coronary occlusion followed by reperfusion. |
| Fish protein hydrolysate reduces plasma total cholesterol, increases the proportion of HDL cholesterol, and lowers acyl-CoA:cholesterol acyltransferase activity in liver of Zucker rats Wergedahl, H., B. Liaset, et al. (2004), J Nutr 134(6): 1320-7. Abstract: There is growing evidence that soy protein improves the blood lipid profiles of animals and humans. We compared the effects of fish protein hydrolysate (FPH), soy protein, and casein (control) on lipid metabolism in Wistar rats and genetically obese Zucker (fa/fa) rats. In Zucker rats, FPH treatment affected the fatty acid composition in liver, plasma, and triacylglycerol-rich lipoproteins. The mRNA levels of Delta 5 and Delta 6 desaturases were reduced by FPH and soy protein feeding compared with casein feeding. In Zucker rats both FPH and soy protein treatment reduced the plasma cholesterol level. Furthermore, the HDL cholesterol:total cholesterol ratio was greater in these rats and in the Wistar rats fed FPH and soy protein compared with those fed casein. Although fecal total bile acids were greater in soy protein-fed Zucker rats than in casein-fed controls, those fed FPH did not differ from the controls. However, the acyl-CoA:cholesterol acyltransferase activity was reduced in Zucker rats fed FPH and tended to be lower (P = 0.13) in those fed soy protein compared with those fed casein. Low ratios of methionine to glycine and lysine to arginine in the FPH and soy protein diets, compared with the casein diet, may be involved in lowering the plasma cholesterol concentration. Our results indicate that the effects of FPH and soy protein on fatty acid metabolism are similar in many respects, but the hypocholesterolemic effects of FPH and soy protein appear to be due to different mechanisms. FPH may have a role as a cardioprotective nutrient. |
| Five hourly measurements of serum cholesterol levels: a new methodology to assess and evaluate stress, good health and disease Bhacca, N. S. (2000), Med Hypotheses 54(6): 962-8. Abstract: Research has developed a concrete link between psychological/emotional stress and life-threatening diseases such as heart disease and cancer. Here we present a technique to assess the magnitude of stress from cholesterol variation number (CVN). This number is the difference between the highest and the lowest cholesterol concentrations that relates to the five hourly cholesterol measurements performed over a five hour span. Since cholesterol in serum arises from the liver, the CVN is equated with the fluctuations in hepatic biosynthesis. This relationship is explained on the basis of the rhythmic hormonal secretions associated with cholesterol biosynthesis. Whenever stress-induced aberrations in timing of hormonal secretions occur, CVN changes. Individuals with lower CVN would have overall better health than persons with higher CVN. Thus by utilizing CVN, physicians may be able to differentiate cardiovascular health of individuals with the same or very similar serum cholesterol concentrations. |
| Five-year trend in serum HDL-lipoprotein cholesterol in the Finnish population aged 25-64 years. A suggestion of an increase Salomaa, V. V., M. Jauhiainen, et al. (1991), Atherosclerosis 86(1): 39-48. Abstract: High density lipoprotein cholesterol (HDLC) was measured in the population surveys carried out in Finland in 1982 and 1987. The mean (+/- SD) of HDLC for men aged 25-64 years was 1.23 +/- 0.32 mmol/l in 1982 and 1.30 +/- 0.33 mmol/l in 1987, the increase being 5.7%. Respective values in women were 1.46 +/- 0.33 mmol/l and 1.58 +/- 0.35 mmol/l, an increase of 8.2%. The increase was significantly greater in women than in men (P less than 0.001). The prevalence of low HDLC (less than or equal to 0.9 mmol/l) fell from 13.5 to 9.6% in men and from 3.2 to 1.4% in women. Factors associated with low HDLC were the history of ischemic heart disease (IHD), diabetes and hypertension in both sexes and the positive family history of IHD in women. Subjects with low HDLC also had higher body mass index (BMI), waist-hip ratio and serum total cholesterol (TC) concentration than subjects with normal HDLC. Changes in BMI, waist-hip ratio, alcohol intake, leisure time physical activity, prevalence of smoking or in the dietary variables recorded, did not explain the increase in HDLC. |
| Flaxseed reduces plasma cholesterol and atherosclerotic lesion formation in ovariectomized Golden Syrian hamsters Lucas, E. A., S. A. Lightfoot, et al. (2004), Atherosclerosis 173(2): 223-9. Abstract: BACKGROUND: Dietary modification contributes significantly in reducing cardiovascular disease (CVD) risk factors including lowering cholesterol and atherosclerosis. The purpose of this study was to investigate the effects of flaxseed, a rich source of lignans, alpha-linolenic acid and soluble fiber mucilage, on the prevention of ovariectomy-induced rise in total cholesterol and atherosclerotic lesions. METHODS: Seventy-two 6-month-old female Golden Syrian hamsters were either ovariectomized (ovx) or sham-operated (sham) and randomly assigned to six groups (n = 12): sham, ovx, or ovx plus either 17beta-estradiol (E(2), 10 microg/kg body weight) or semi-purified diet adjusted for macronutrients and fiber to contain one of the three doses of flaxseed (7.5, 15, or 22.5%) for 120 days. RESULTS: Ovariectomy significantly elevated plasma total-, HDL-, and free-cholesterol concentrations. Similar to estrogen, all doses of flaxseed were effective in preventing the ovx-induced rise in plasma total cholesterol. Triglyceride concentrations were significantly higher in the flax-fed hamsters. There were no significant differences in plasma non-HDL- and esterified-cholesterol among the treatment groups. Ovariectomy also increased the number of hamsters with lesions and the aortic fatty streak area. All three doses of flaxseed reduced the fatty streak area and the incidence of lesions to levels similar to the sham group. CONCLUSION: The findings of this study show that flaxseed is beneficial in reducing plasma cholesterol and plaque formation induced by ovarian hormone deficiency. |
| Flexible modeling of the effects of serum cholesterol on coronary heart disease mortality Abrahamowicz, M., R. du Berger, et al. (1997), Am J Epidemiol 145(8): 714-29. Abstract: Current understanding of the impact of lipids and other risk factors on coronary heart disease is largely based on the results of parametric multiple regression analyses of large prospective studies. To assess the potential impact of the a priori assumption of linearity of continuous risk factors on the results of parametric analyses, the authors completed a secondary analysis of the Lipid Research Clinics Prevalence and Follow-up Studies (1972-1987) data using an assumption-free nonparametric modeling approach. The effects of total serum cholesterol and the ratio of total serum cholesterol to high density lipoprotein cholesterol, adjusted for common risk factors, were estimated using a smoothing spline method available in the generalized additive model extension of the multiple logistic regression. The data set included 2,512 men in the random sample of the Lipid Research Clinics study who did not take lipid-lowering medications. During the median follow-up of 12.6 years, 94 coronary heart disease deaths occurred. The generalized additive model fits the effects of total serum cholesterol (p < 0.01) and the ratio of total serum cholesterol to high density lipoprotein cholesterol (p < 0.02) significantly better than the parametric logistic regression. Validation studies confirmed that, among new observations arising from the same population, generalized additive model estimates predicted outcomes better than the parametric estimates. Nonlinear effects of both lipid measures were robust and may be clinically important. The authors conclude that the linearity assumption inherent in parametric models may result in biased estimates of the effects of total serum cholesterol on coronary heart disease mortality and recommend that their findings be verified in a nonparametric analysis of data from another large prospective study. |
| Florida's response to the Physician's National Cholesterol Education Program Schocken, D. D. and D. M. Schocken (1992), J Fla Med Assoc 79(2): 112-6. Abstract: To assess the impact of the National Cholesterol Education Program (NCEP) guidelines, the 7,347 primary care members of the Florida Medical Association received a confidential mailed questionnaire. A follow-up survey polling 5% of the nonresponders validated the initial observations. Of the 1,909 analyzed returns, 96% of the physicians' responses indicated that they believed cholesterol is an important factor in preventing atherosclerosis. However, responses to other questions were far less uniform. For example, 92% of general internists (n = 495) reported being aware of the NCEP guidelines versus 98% of cardiologists (n = 212) (p less than.01) and only 78.7% of OB/GYN specialists (n = 218) (p less than.0001). While 88.2% of general internists responded that the guidelines were relevant in treating their patients, 80.2% of OB/GYN physicians answered likewise (p less than.03). Moreover, only 54% of OB/GYN specialists reported routinely measuring serum cholesterol in their patients compared to 96.7% of general internists (p less than.0001). Most Florida primary care physicians are aware of the NCEP guidelines; however, the impact varies widely among practitioners. |
| Flow injection determination of free and total cholesterol in animal greases using enzymes in non-aqueous media Pineiro-Avila, G., A. Salvador, et al. (1998), Analyst 123(5): 999-1003. Abstract: A non-covalently coimmobilized bienzymic reactor of horseradish peroxidase (HRP) and cholesterol oxidase (COD), operating in a continuous organic flowing stream of 1X10-3 M p-anisidine in buffer-saturated (pH 7.0) toluene, has been employed for cholesterol determination in animal greases, such as pig, beef, and chicken fat, and codfish liver oil. The method provides a good linear relationship up to 1.8 X 10-3 M cholesterol and average recoveries of 99.5%, a high sensitivity, with a detection limit of 1 X 10-6 M of cholesterol and a good precision (an interday RSD of 1.8% for the determination of total cholesterol in a codfish oil sample). The method permits the direct spectrophotometric determination of free cholesterol present in animal grease samples without any pre-treatment, and the total cholesterol determination after a microwave-assisted saponification. The bienzymic reactor exhibits a good stability in the water-restricted environment, being possible to perform more than 180 analyses during a period of 10d with 1mg of HRP, and 1 mg of COD, equivalent to 220 purpurogallin units and 23 U, respectively. |
| Flow-dependent stimulation of sodium and cholesterol uptake and cell growth in cultured vascular smooth muscle Rosati, C. and R. Garay (1991), J Hypertens 9(11): 1029-33. Abstract: A10 vascular smooth muscle cells were placed in a flow chamber and exposed to the circulation of foetal calf serum at different rates and pressures. Under unidirectional laminar flow, physiological flow rates and pressures had almost no effect on internal sodium content. Indeed, pressure values greater than 150 mmHg were required to observe modest increases in sodium content. Conversely, a short exposure to turbulent flow (3 min) induced a strong increase in cell sodium content. At flow rates found in large human arteries, the onset of such ionic change required pressure levels of 50-85 mmHg. The restoration of laminar flow allowed the elimination of the excess cell sodium content, with a half-life of 3-4 h. Opening of calcium channels by the turbulent flow was suggested by the following observations: (1) nitrendipine fully prevented sodium uptake, with an inhibitory concentration of 50% of approximately 2 x 10(-7) mol/l; and (2) exposure to turbulent flow increased cytosolic free calcium content by approximately 80%. In addition to sodium uptake, turbulent flow stimulated cell uptake of exogenous cholesterol. Although the restoration of laminar flow allowed the rapid elimination of approximately two-thirds of the excess in cell cholesterol (with a half-life of 30-60 min), one-third of the excess cholesterol remained in the cells for more than 24 h. Finally, cell replication was faster in cells exposed to turbulent flow than in control cells subjected to laminar flow. The results show that turbulent flow provokes membrane ion transport changes in vascular smooth muscle cells, which are associated with enhanced cholesterol uptake and cell hyperplasia. Therefore, the departure from unidirectional laminar flow may be a pathogenic factor in primary hypertension and/or atherosclerosis. |
| Flow-mediated vasoactivity and circulating adhesion molecules in hypertriglyceridemia: association with small, dense LDL cholesterol particles Lupattelli, G., R. Lombardini, et al. (2000), Am Heart J 140(3): 521-6. Abstract: BACKGROUND: Endothelial dysfunction is considered one of the earliest events in the process of atherosclerosis, and an impaired vasodilatory response has been reported in patients with dyslipidemias. However, the independent association between hypertriglyceridemia and endothelial dysfunction is controversial, and the relation between endothelium-dependent vasodilation and circulating cell adhesion molecules as markers of endothelial dysfunction has not been fully determined. METHODS: Brachial artery flow mediated vasodilation (FMV) and the soluble forms of vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) were determined after overnight fasting in 16 men with hypertriglyceridemia (age 33 +/- 6 years) and in 16 age-matched healthy men with normal triglycerides and cholesterol. Subjects who smoked and those with known cardiovascular disease, diabetes, hypertension, recent or active infections, or any other disease that could affect leukocyte activation were excluded from the study. RESULTS: Compared with normal subjects, subjects with hypertriglyceridemia showed a higher level of sVCAM-1 and sICAM-1 (both P <.001), a reduced FMV (P <.01), and a smaller LDL particle size (P <.05). FMV had a significant inverse correlation with sVCAM-1 (r = -0.61, P <.001) and sICAM-1 (r = -0.38, P <.03). LDL particle size had a strong, direct association with FMV (r = 0.75, P <.001) and an inverse association with adhesion molecules. By multiple regression analysis, triglycerides (P <.001) and small LDL particle size (P <.002) predicted a reduced FMV. CONCLUSIONS: Serum level of cell adhesion molecules is increased and FMV is impaired in young healthy men with hypertriglyceridemia compared with age-matched men with normal lipid levels. Small, dense LDL particles may play a role in determining endothelial dysfunction in these subjects. |
| Flow-mediated vasodilation is not impaired when HDL-cholesterol is lowered by substituting carbohydrates for monounsaturated fat de Roos, N. M., M. L. Bots, et al. (2001), Br J Nutr 86(2): 181-8. Abstract: Low-fat diets, in which carbohydrates replace some of the fat, decrease serum cholesterol. This decrease is due to decreases in LDL-cholesterol but in part to possibly harmful decreases in HDL-cholesterol. High-oil diets, in which oils rich in monounsaturated fat replace some of the saturated fat, decrease serum cholesterol mainly through LDL-cholesterol. We used these two diets to investigate whether a change in HDL-cholesterol would change flow-mediated vasodilation, a marker of endothelial function. We fed thirty-two healthy volunteers two controlled diets in a weeks' randomised cross-over design to eliminate variation in changes due to differences between subjects. The low-fat diet contained 59.7 % energy (en%) as carbohydrates and 25.7 en% as fat (7.8 en% as monounsaturates); the oil-rich diet contained 37.8 en% as carbohydrates and 44.4 en% as fat (19.3 en% as monounsaturates). Average (sd) serum HDL-cholesterol after the low-fat diet was 0.21 (sd 0.12) mmol/l (8.1 mg/dl) lower than after the oil-rich diet. Serum triacylglycerols were 0.22 (sd 0.28) mmol/l (19.5 mg/dl) higher after the low-fat diet than after the oil-rich diet. Serum LDL and homocysteine concentrations remained stable. Flow-mediated vasodilation was 4.8 (SD 2.9) after the low-fat diet and 4.1 (SD 2.7) after the oil-rich diet (difference 0.7 %; 95 % CI -0.6, 1.9). Thus, although the low-fat diet produced a lower HDL-cholesterol than the high-oil diet, flow-mediated vasodilation, an early marker of cardiovascular disease, was not impaired. |
| Flow-responsive remodeling after angioplasty is enhanced by high cholesterol diet. Prevention with pyrrolidine dithiocarbamate Ward, M. R., P. S. Tsao, et al. (2003), Atherosclerosis 168(2): 333-41. Abstract: We examined the effects of high cholesterol diet and pyrrolidine dithiocarbamate (PDTC) on flow-dependent remodeling after angioplasty. After right common carotid balloon-injury, the right external carotid (low flow) or left common carotid artery were ligated (high flow) in rabbits fed normal diet, 1% cholesterol diet without or with the antioxidant PDTC for 7 days pre- and 7-28 days post-injury. Angiographic lumen diameter was significantly greater at 28 days in high flow than low flow normal diet animals, attributable on perfusion-fixed vessel morphometry to altered remodeling (area within the external elastic lamina: high flow 1.85+/-0.24 vs. low flow 1.31+/-0.04 mm(2), P<0.05) rather than differences in neointima formation or vessel tone. In animals on 1% cholesterol diet high flow remodeling was significantly enhanced (area within the external elastic lamina 3.13+/-0.17 mm(2), P<0.05 vs. high flow normal diet) but low flow inward remodeling was similar (area within the external elastic lamina 1.29+/-0.07 mm(2)). Mean Doppler flow velocities (initial/post-ligation/28 day follow-up, cm/s) had almost normalized in normal diet animals (high flow 30/49/35, low flow 32/9/26) but showed overcompensation in 1% cholesterol diet animals (high flow 32/49/22, low flow 30/11/25). PDTC therapy markedly attenuated remodeling (area within the external elastic lamina: high flow 2.20+/-0.18, and low flow 2.00+/-0.11 both P<0.05 vs. 1% cholesterol diet alone) and flow velocities only partially normalized (high flow 26/42/34, low flow 27/7/16). We conclude that hypercholesterolemia enhances and PDTC attenuates flow-dependent remodeling after angioplasty. |
| Fluctuations of urea, cholesterol and triglyceride concentrations in plasma of clinically health piglets during the first four weeks of life Wehrend, A., J. Tschachtschal, et al. (1999), Dtsch Tierarztl Wochenschr 106(12): 506-9. Abstract: The present study was designed to investigate fluctuations of plasma concentrations in urea, cholesterol and triglyceride in healthy piglets (Landrace x Pietrain) during the first four weeks of life. Blood samples were taken by venipuncture in 240 piglets thirty minutes after birth, after 6, 24, 48, 168, 336, 504 and 672 hours. Cholesterol and triglyceride concentrations exhibited minimum values after delivery and rose up to the 48th hour of life, what can be explained by colostrum intake. Although an increase of urea after birth was determined, but some of the following measured concentrations were under the initial value. The three parameters showed a significant dependency on the age (p < 0.001). After 6 hours there was a correlation of cholesterol concentration and sex (p = 0.001) and triglyceride concentrations have been correlated to body temperature after 24 and 48 hours (p = 0.009; p = 0.004). Before colostrum intake urea concentration has been associated to body temperature (0.001). The physiological significance of the observed fluctuations for adaptation from an intrauterine to an extrauterine life is discussed. |
| Fluid resuscitation, nutritional support, and cholesterol in critically ill postsurgical patients Sun, X., D. Oberlander, et al. (1998), J Clin Anesth 10(4): 302-8. Abstract: STUDY OBJECTIVE: To determine how and why cholesterol concentrations decrease after surgery, and the effect of the administration of nutritional support. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: 213 consecutive patients admitted to a surgical intensive care unit after major surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serum concentrations of cholesterol, serum albumin and total protein. The initial portion of this study demonstrated that serum concentrations of cholesterol, like those of serum albumin and total protein, decreased by approximately 30% immediately following surgery. These changes were directly related to changes in hematocrit and inversely correlated with the volume of perioperative intravenous (IV)fluid, the degree of positive fluid balance, and the estimated blood loss. The study's second phase examined the 19 patients who received at least 10 days of nutritional support. After 1 week of feeding, serum total protein concentrations increased significantly, but did not return to preoperative levels. Serum concentrations of cholesterol, which were markedly decreased prior to nutritional repletion, increased significantly after 9 days of treatment. The changes in serum cholesterol concentration were negatively correlated (r = -0.32) with the daily intake of IV fluid. CONCLUSION: Serum cholesterol concentrations, like those of serum albumin and total protein, are markedly reduced immediately following major abdominal surgery, often to levels reported in malnutrition. Dilution by IV fluid and redistribution into an expanded extracellular fluid space are likely the major causes of these decreases. Serum cholesterol concentrations are therefore not useful in the nutritional assessment of patients in the immediate postoperative period. |
| Fluorescence imaging of two-photon linear dichroism: cholesterol depletion disrupts molecular orientation in cell membranes Benninger, R. K., B. Onfelt, et al. (2005), Biophys J 88(1): 609-22. Abstract: The plasma membrane of cells is an ordered environment, giving rise to anisotropic orientation and restricted motion of molecules and proteins residing in the membrane. At the same time as being an organized matrix of defined structure, the cell membrane is heterogeneous and dynamic. Here we present a method where we use fluorescence imaging of linear dichroism to measure the orientation of molecules relative to the cell membrane. By detecting linear dichroism as well as fluorescence anisotropy, the orientation parameters are separated from dynamic properties such as rotational diffusion and homo energy transfer (energy migration). The sensitivity of the technique is enhanced by using two-photon excitation for higher photo-selection compared to single photon excitation. We show here that we can accurately image lipid organization in whole cell membranes and in delicate structures such as membrane nanotubes connecting two cells. The speed of our wide-field imaging system makes it possible to image changes in orientation and anisotropy occurring on a subsecond timescale. This is demonstrated by time-lapse studies showing that cholesterol depletion rapidly disrupts the orientation of a fluorophore located within the hydrophobic region of the cell membrane but not of a surface bound probe. This is consistent with cholesterol having an important role in stabilizing and ordering the lipid tails within the plasma membrane. |