Enhanced fatty streak formation in C57BL/6J mice by immunization with heat shock protein-65.
(1/563)
Recent data suggest that the immune system is involved in atherogenesis. Thus, interest has been raised as to the possible antigens that could serve as the initiators of the immune reaction. In the current work, we studied the effects of immunization with recombinant heat shock protein-65 (HSP-65) and HSP-65-rich Mycobacterium tuberculosis (MT) on early atherogenesis in C57BL/6J mice fed either a normal chow diet or a high-cholesterol diet (HCD). A rapid, cellular immune response to HSP-65 was evident in mice immunized with HSP-65 or with MT but not in the animals immunized with phosphate-buffered saline (PBS) alone. Early atherosclerosis was significantly enhanced in HCD-fed mice immunized with HSP-65 (n=10; mean aortic lesion size, 45 417+/-9258 microm2) or MT (n=15; 66 350+/-6850 microm2) compared with PBS-injected (n=10; 10 028+/-3599 microm2) or nonimmunized (n=10; 9500+/-2120 microm2) mice. No fatty streak lesions were observed in mice fed a chow diet regardless of the immunization protocol applied. Immunohistochemical analysis of atherosclerotic lesions from the HSP-65- and MT-immunized mice revealed infiltration of CD4 lymphocytes compared with the relatively lymphocyte-poor lesions in the PBS-treated or nonimmunized mice. Direct immunofluorescence analysis of lesions from HSP-65- and MT-immunized mice fed an HCD exhibited extensive deposits of immunoglobulins compared with the fatty streaks in the other study groups, consistent with the larger and more advanced lesions found in the former 2 groups. This model, which supports the involvement of HSP-65 in atherogenesis, furnishes a valuable tool to study the role of the immune system in atherogenesis. (+info)
Effects of inhaled oxygen concentration on fat metabolism during propofol infusion in rabbits.
(2/563)
We have investigated the effect of inhaled oxygen tension on lipid metabolism during propofol infusion. Propofol is supplied as a lipid emulsion containing 10% soybean oil, which is rich in triglycerides (TG). Infused TG are metabolized via three pathways in the liver cell; Krebs cycle, ketogenesis and release as very low density lipoproteins (VLDL) into the blood. For this reason, we measured TG and the products of the three pathways; carbon dioxide, ketone bodies and VLDL. Thirty-two rabbits were anaesthetized under four different conditions: propofol under hyperoxia, normoxia, hypoxia and isoflurane anaesthesia under hyperoxia. Our results indicated that hyperoxia produced more ketone bodies, normoxia more PaCO2 and hypoxia more free fatty acids (FFA) and TG compared with the other propofol infusion groups. We conclude that hyperoxia during propofol infusion facilitated fat metabolism through ketogenesis, while normoxia did so via the Krebs cycle. Also, hypoxia suppressed utilization of TG and VLDL production in the liver. (+info)
Effects of age on concentrations of plasma cholecystokinin, glucagon-like peptide 1, and peptide YY and their relation to appetite and pyloric motility.
(3/563)
BACKGROUND: Aging is associated with a decrease in appetite and a slowing of gastric emptying. The gastrointestinal hormones cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), and peptide YY (PYY) may mediate these changes. OBJECTIVE: We investigated whether aging influenced the secretion of CCK, GLP-1, and PYY and their effects on appetite and pyloric motility. DESIGN: Eight healthy older (65-80 y) and 7 younger (20-34 y) men received isoenergetic (12.1 kJ/min) intraduodenal infusions of lipid and glucose for 120 min on separate days. Plasma CCK, GLP-1, and PYY concentrations were measured. RESULTS: Plasma CCK concentrations were higher in older than in younger subjects (P = 0.004) as a result of higher baseline values (4.7+/-0.2 compared with 3.2+/-0.2 pmol/L; P < 0.0001) and a greater rise during lipid infusion (increase from baseline: 7.1+/-0.5 compared with 5.3+/-0.6 pmol/L; P = 0.048). Plasma GLP-1 and PYY concentrations were not significantly different between groups. The decrease in hunger during intraduodenal lipid infusion was inversely related to the increase in CCK, GLP-1, and PYY in younger but not older subjects. During intraduodenal lipid infusion, the increase in isolated pyloric pressure wave (IPPW) frequency was positively related to GLP-1 and PYY and the increase in IPPW amplitude was positively related to CCK in older but not younger subjects, whereas the increase in IPPW amplitude and pyloric tone was negatively related to GLP-1 and PYY in younger subjects. CONCLUSIONS: Human aging is associated with increased CCK concentrations, which may contribute to the slowing of gastric emptying, mediated by increased pyloric motility. The role of increased plasma CCK concentrations in mediating the age-related decrease in appetite remains to be established. (+info)
Metabolic, gastrointestinal, and CNS neuropeptide effects of brain leptin administration in the rat.
(4/563)
To investigate whether brain leptin involves neuropeptidergic pathways influencing ingestion, metabolism, and gastrointestinal functioning, leptin (3.5 micrograms) was infused daily into the third cerebral ventricular of rats for 3 days. To distinguish between direct leptin effects and those secondary to leptin-induced anorexia, we studied vehicle-infused rats with food available ad libitum and those that were pair-fed to leptin-treated animals. Although body weight was comparably reduced (-8%) and plasma glycerol was comparably increased (142 and 17%, respectively) in leptin-treated and pair-fed animals relative to controls, increases in plasma fatty acids and ketones were only detected (132 and 234%, respectively) in pair-fed rats. Resting energy expenditure (-15%) and gastrointestinal fill (-50%) were reduced by pair-feeding relative to the ad libitum group, but they were not reduced by leptin treatment. Relative to controls, leptin increased hypothalamic mRNA for corticotropin-releasing hormone (CRH; 61%) and for proopiomelanocortin (POMC; 31%) but did not reduce mRNA for neuropeptide Y. These results suggest that CNS leptin prevents metabolic/gastrointestinal responses to caloric restriction by activating hypothalamic CRH- and POMC-containing pathways and raise the possibility that these peripheral responses to CNS leptin administration contribute to leptin's anorexigenic action. (+info)
Organochlorines in breast milk from two cities in Ukraine.
(5/563)
Reports of environmental problems in the former Soviet Union, including excess use of pesticides, have led to concerns about high levels of contamination in humans, but little information is available to assess whether these concerns are warranted. Samples of breast milk from 197 women from two cities in Ukraine were analyzed for p,p'-DDT, p,p'-DDE, endrin, dieldrin, heptachlor epoxide, trans-nonachlor, oxychlordane, hexachlorobenzene, ss-hexachlorocyclohexane (HCH), and 18 polychlorinated biphenyl congeners, and results were compared to previous reports from Europe. The median ss-HCH concentration was 731 ng/g milk fat, which is higher than other reports from Europe but lower than reports from other parts of the world. The median DDE concentration was 2,457 ng/g milk fat, which is higher than most but not all other reports from Europe. Concentrations of other chemicals were comparable to or lower than other reports from Europe. Concentrations from the city of Kyiv were generally lower than those from Dniprodzerzhinsk, but the magnitudes of these differences were modest. (+info)
Cardiac (n-3) non-esterified fatty acids are selectively increased in fish oil-fed pigs following myocardial ischemia.
(6/563)
The effect of fish oil supplementation on the nonesterified fatty acid (NEFA) concentration and composition in the normoxic and hypoxic myocardium of pigs was examined. Two groups of female pigs (n = 7) were fed a diet supplemented with either 5 g beef tallow/kg (as control) or 5 g fish oil/kg (MaxEPA) rich in (n-3) fatty acids. After 6 wk of supplementation, the pigs were anesthetized, hearts exposed by thoracotomy followed by occlusion of the left anterior descending artery. Normoxic and hypoxic regions of the heart were examined for NEFA concentration and composition by using a combination of thin layer and gas chromatography. Nonesterified (n-6) and (n-3) fatty acid concentration and composition differed significantly between the two groups in both the normoxic and hypoxic areas of the heart. Eicosapentaenoic and docosahexaenoic acid concentration in the NEFA fraction of the normoxic myocardium were higher in the fish oil group than in the beef tallow group (P < 0.001). In the fish oil-fed pigs, the (n-3) NEFA concentration was significantly higher in the hypoxic compared to the normoxic region of the heart. The fish oil-fed group had lower levels of arachidonic acid in the NEFA fraction compared to the beef tallow-fed group, whereas the hypoxic myocardium had higher levels of arachidonic acid, regardless of the dietary fat supplementation. Despite large differences in the proportions of saturated fatty acids in the experimental diets, there was little or no difference in the saturated fatty acid content of cardiac phospholipid and NEFA fractions. Following myocardial ischemia, (n-3) fatty acids in the NEFA fractions were selectively increased in the fish oil-fed pigs, implicating the possible role of nonesterified (n-3) polyunsaturated fatty acids in the prevention of arrhythmias. (+info)
Influence of pig substitution on milk yield, litter weights, and milk composition of machine milked sows.
(7/563)
This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary. (+info)
Lymphatic absorption of structured triglycerides vs. physical mix in a rat model of fat malabsorption.
(8/563)
Comparison was made between the intestinal absorption and lymphatic transport of a randomly interesterified fish oil and medium-chain triglyceride (MCT) structured triglycerides (STG) vs. the physical mix in rat small intestine following ischemia and reperfusion (I/R) injury. Under halothane anesthesia, the superior mesenteric artery (SMA) was occluded for 20 min and then reperfused in I/R rats. The SMA was isolated but not occluded in control rats. In both treatment groups, the mesenteric lymph duct was cannulated and a gastric tube was inserted. Each treatment group received 1 ml of the fish oil-MCT STG or physical mix (7 rats/group) through the gastric tube followed by an infusion of PBS at 3 ml/h for 8 h. Lymph was collected hourly for 8 h. Lymph triglyceride, cholesterol, and decanoic and eicosapentaenoic acids increased rapidly and maintained a significantly higher output (P < 0.01) with STG compared with physical mix in control rats over 8 h. After I/R, lymphatic triglyceride output decreased 50% compared with control. Gastric infusion of STG significantly improved lipid transport by having a twofold higher triglyceride, cholesterol, and decanoic and eicosapentaenoic acids output to lymph compared with its physical mix (P < 0.01). We conclude that STG is absorbed into lymph significantly better than physical mix by both the normal intestine and the intestine injured by I/R. (+info)