6,680 research outputs found
The influence of dietary fat concentration on fatty acid signatures and stable carbon isotopes of fatty acids in liver of Atlantic pollock (Pollachius virens)
No full textA number of biomarker techniques have been employed to investigate animal diets, including analyses of fatty acid (FA) proportions and stable carbon isotopic signatures. Here, the influence of dietary FA concentrations on fish FA signatures and δ13C values of FA in fish liver was evaluated by feeding Atlantic pollock (Pollachius virens; n=108) three diets with different FA concentrations for 20 weeks. Calibration coefficients (CC) and discrimination factors were calculated to compare the FA profile and δ13C values of FA in liver to those of diet. Most CC showed significant variation across the three diets; however, a number of FA present in smaller proportions had CC that did not vary among the diets. Overall, the two CC sets derived from experiments utilizing feeds with the higher FA concentrations were very similar to each other and showed substantial variation compared to CC derived from feeding the diet with the lowest FA concentrations. Using Quantitative Fatty Acid Signature Analysis (QFASA) and the initial samples of pollock, the three sets of CC derived from fish fed the three treatment diets were applied to determine the influence of these three CC on diet estimates. The results indicated that QFASA may be less sensitive to variation in CC than previously assumed. Discrimination factors calculated using liver and diet δ13C values varied with dietary FA concentration for five of ten FA. Most discrimination factors for saturated and monounsaturated FA (MUFA) showed significant deviations from zero; in contrast, few discrimination factors for polyunsaturated FA (PUFA), specifically 20:5n-3 and 22:6n-3, were significantly different than zero. These results suggest that δ13C values for PUFA sampled from a wild fish would closely mirror that of the prey consumed. Combined biomarker techniques, employing both FA proportions and δ13C values, may prove to be the most reliable in estimating diets of animals in the wild at this time
Reducing DCO registrations through electronic matching of cancer registry data and routine hospital data
No full textFrom twelve months after its original publication, this work is licensed under the Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0
Efecto de la adición de proteínas solubles recuperadas del agua de lavado de surimi de Pacific Whiting sobre las propiedades funcionales y mecánicas de surimi de Alaska pollock grado FA
No full textSoluble proteins from surimi wash water (SWW) can be insolubilized by complexing with chitosan-alginate allowing its recovery and the reduction of the organic matter in the processing water discharged from surimi processing plants. The objective of this work was to evaluate the effect of adding soluble proteins recovered from Pacific whiting SWW on the mechanical and functional properties of commercial Alaska Pollock surimi grade FA. Levels evaluated were 0 (control), 10, 30 and 50 g insolubilized SWW solids/kg Alaska Pollock grade FA surimi. The mechanical and functional properties of Alaska Pollock surimi pastes and gels were characterized by texture profile analysis (TPA), puncture test, expressible water (EW) and color attributes. TPA and puncture test parameters increased significantly (P≤0.05) when 10–30 g/kg of soluble proteins from Pacific whiting SWW were added. EW values increased also, indicating a decrease of the water holding capacity. Color parameters showed that all surimi gels increased in redness, an undesirable effect in the production of Alaska Pollock grade FA surimiLas proteínas solubles del agua de lavado del surimi (ALS) pueden ser insolubilizadas por medio de la formación de complejos con quitosano y alginato. Su recuperación por este método permite reducir la materia orgánica en el agua de proceso. El objetivo de este trabajo fue evaluar el efecto de la adición de proteína soluble recuperada del ALS de Pacific whiting sobre las propiedades mecánicas y funcionales de surimi comercial de Alaska Pollock de grado FA. Los niveles de adición evaluados fueron 0 (control), 10, 30 y 50 g sólidos insolubilizados de ALS/kg de surimi de Alaska Pollock de grade FA. Las propiedades mecánicas y funcionales se caracterizaron por medio del análisis de perfil de textura (TPA), prueba de punción, agua extraíble y atributos de color. Los valores de los parámetros de TPA y prueba de punción incrementaron significativamente (P≤0.05) cuando se adicionaron de 10 a 30 g/kg de proteínas solubles de ALS de Pacific whiting. El agua extraíble también se incrementó, indicando un descenso de la capacidad de retención de agua. Los atributos de color indicaron que todos los geles de surimi incrementaron su color rojo, lo cual podría ser desfavorable para la producción de surimi de Alaska Pollock grado FAThis work was partially supported by Grant no. NA
16RG 1039 (Project no. R/SF-29) from the National Oceanic
and Atmospheric Administration to the Sea Grant College
Program at Oregon State University, and appropriations
made by the Oregon State Legislature. Part of this study
was supported by Grant no. TAMPS-2003-C02-14, FOMIXCONACYT,
MéxicoS
Reduced sensitivity of fa/fa Zucker rats to adrenomedullin
No full textRat adrenomedullin is a peptide vasodepressor that may be of importance in the pathogenesis of hypertensive disease. Because of the known link between obesity and hypertension, we hypothesized that decreased responsiveness to adrenomedullin might be seen in an obese rodent model. In this study, the in vivo vasodilator actions of exogenous adrenomedullin were compared in anesthetized lean (n = 7) and obese (fa/fa) Zucker rats (n = 8). Adrenomedullin dose dependently lowered mean arterial pressure in both phenotypes, but the half-maximal dose (ID50) was 2-fold higher in fa/fa rats (1.7 +/- 0.22 vs. 0.83 +/- 0.06 nmol/kg). Moreover, the duration of effect was markedly reduced in the fa/fa rats, to 1-2 min from about 5 min in the lean animals. There was no evidence for an increased rate of degradation of adrenomedullin in the fa/fa rats. Although the rats used in this study were not hypertensive, adrenomedullin had reduced sensitivity and duration of action. The evidence suggests possible defects at the target receptor or altered metabolism of adrenomedullin in obesity.LR: 20061115; PUBM: Print; JID: 0372712; 0 (Peptides); 0 (Vasodilator Agents); 148498-78-6 (Adrenomedullin); ppublishSource type: Electronic(1
Identification of biochemical defects in pancreatic islets of fa/fa rats: a developmental study
No full textAdult obese (fa/fa) Zucker rats hypersecrete insulin in response to glucose and other secretagogues. Functional changes in islet alpha 2-adrenoceptors (8) and glycolytic regulation (9) have been reported. In this study, the development of these biochemical lesions in islets isolated from suckling (3 week old) and weanling (5 week old) lean and fa/fa rats was investigated and compared to results in adult animals. Glucose (15 mM)-induced insulin secretion was inhibited by mannoheptulose (MH) in lean (n = 8) but not fa/fa (n = 10) adult rats, indicating loss of sensitivity of glucokinase to competitive inhibition. Sensitivity to MH was somewhat reduced in the islets of 3- and 5-week-old fa/fa (n = 7 and 12) compared to lean (n = 15 and 9) rats, requiring 30-100 fold higher concentrations to achieve significant inhibition. At 3 weeks of age fa/fa rats did not differ from lean controls in either islet insulin content or body weight, but both parameters were increased in fa/fa rats by 5 weeks. The presence of altered alpha 2-adrenoceptor function in fa/fa rats could not be confirmed in this study. Unlike the previous report, prazosin did not antagonize alpha 2-agonist mediated inhibition of insulin secretion. The presence of defective regulation of the glycolytic pathway by mannoheptulose in suckling and weanling rats may contribute to development of hyperinsulinemia in fa/fa rats.LR: 20061115; PUBM: Print; JID: 9305691; 0 (Receptors, Adrenergic, alpha); 11061-68-0 (Insulin); 50-99-7 (Glucose); 654-29-5 (Mannoheptulose); EC 2.7.1.2 (Glucokinase); ppublishSource type: Electronic(1
Effect of adrenalectomy on the development of a pancreatic islet lesion in fa/fa rats
No full textAdrenalectomy prevents development of obesity and hyperinsulinaemia in obese (fa/fa) Zucker rats, thereby implicating the hypothalamo- pituitary-adrenal axis in the pathogenesis of obesity. In this study glucose-induced insulin secretion and glucokinase activity were investigated in isolated islets from adrenalectomized and control obese and lean female rats. Islets from control fa/fa rats were more sensitive to glucose with a half-maximal effective concentration (EC50) of 6.1 +/- 2.0 mmol. 1(-1) compared with 10.6 +/- 2.7 mmol. 1(-1) for adrenalectomized fa/fa rat islets. Adrenalectomy did not alter the islet sensitivity to glucose in the lean rats (EC50 of 9.4 +/- 1.5 mmol.1(-1) and 9.3 +/- 2.0 mmol. 1(-1) for adrenalectomized and control lean rats respectively). Mannoheptulose did not inhibit insulin secretion from control obese rats; however at concentrations of 1.0 mmol. 1(-1) or more it significantly inhibited glucose-induced insulin secretion in adrenalectomized obese and lean, and control lean rat islets (P < 0.05). In adrenalectomized fa/fa islets the glucokinase Km was increased twofold compared with the control fa/fa rats (9.5 +/- 1.5 mmol. 1(-1) vs 5.0 +/- 1.5 mmol. 1(-1), respectively), but there was no significant change in glucokinase Km in the lean rat islets after adrenalectomy. Mannoheptulose (10 mmol.1(-1) caused a significant reduction in glucose phosphorylation in disrupted islets of adrenalectomized fa/fa and lean, and of control lean rats, but not of control fa/fa rats. These data demonstrate that development of abnormal regulation of glycolysis in pancreatic islet beta cells of fa/fa rats, as indicated by the insulin response to manno-heptulose and glucokinase activity, is dependent on an intact hypothalamo-pituitary-adrenal axis.LR: 20061115; PUBM: Print; JID: 0006777; 0 (Blood Glucose); 11061-68-0 (Insulin); 50-22-6 (Corticosterone); 50-99-7 (Glucose); 654-29-5 (Mannoheptulose); EC 2.7.1.1 (Hexokinase); EC 2.7.1.2 (Glucokinase); ppublishSource type: Electronic(1
Ultrastructural and secretory heterogeneity of fa/fa (Zucker) rat islets
No full textMany previous studies of obese rodents documented biochemical changes in pancreatic islets that contribute to hyperinsulinemia in vivo. Those studies used heterogeneous populations of islets, although the size of islets from obese rats ranges from 500 microm. Here, functional and morphological changes in size-sorted ( 250 microm diameter) islets from obese Zucker (fa/fa) rats were correlated. Ultrastructural examination revealed that > 250 microm cultured islets had an increased number of immature secretory granules in the beta cells. The number of degranulated beta cells in > 250 and 250 microm, 250 microm islets compared with small islets. Studies of individual beta cells by reverse hemolytic plaque assay revealed 3-fold more cells from > 250 microm islets were stimulated by 1.4 mmol.l(-1) glucose than cells from < 125 microm islets. We conclude that functional defects in mixed size populations of islets from fa/fa rats are mainly due to alterations in the large islets, whereas smaller islets have relatively normal function. Exposure to high glucose exacerbates morphological and functional differences of large islets, which could have important implications in the transition to noninsulin-dependent diabetes when beta cell insulin production is unable to compensate for hyperglycemia.LR: 20061115; PUBM: Print; JID: 7500844; 11061-68-0 (Insulin); 50-99-7 (Glucose); 654-29-5 (Mannoheptulose); 7782-44-7 (Oxygen); ppublishSource type: Electronic(1
Evidence for defective glucose sensing by islets of fa/fa obese Zucker rats
No full textThe hypothesis that a defect in glucose sensing by islets of fa/fa Zucker rats contributes to hyperinsulinemia in these animals was tested. Islets from lean and fa/fa rats were isolated by collagenase digestion and step-density gradient purification and then cultured overnight in Dulbecco's modified Eagle's medium containing 12.5 mM glucose. Obese rat islets were more sensitive to hypoglycemic glucose levels with half-maximal effective concentration (EC50) of 5.6 mM compared with an EC50 of 8.2 mM for lean rat islets. In contrast, responsiveness of both phenotypes to alpha-ketoisocaproate and quinine was similar. Mannoheptulose did not inhibit insulin secretion from fa/fa islets, although inhibitors of later events in the stimulus-secretion coupling pathway were normally inhibited by iodoacetate and diazoxide. Finally, starvation in vivo and culture of islets in low glucose concentrations (5 mM) in vitro both decreased glucose-stimulated insulin secretion from lean but not fa/fa rat islets. We conclude that fa/fa rat islets have an exaggerated insulin response to hypoglycemic stimuli, possibly as a result of a defect in B-cell glucokinase function.LR: 20061115; PUBM: Print; JID: 0372712; 0 (Amino Acids); 0 (Blood Glucose); 0 (Iodoacetates); 11061-68-0 (Insulin); 130-95-0 (Quinine); 364-98-7 (Diazoxide); 50-99-7 (Glucose); 56-65-5 (Adenosine Triphosphate); 64-69-7 (Iodoacetic Acid); 654-29-5 (Mannoheptulose); EC 2.7.1.2 (Glucokinase); ppublishSource type: Electronic(1
Functional characterization of alpha-adrenoceptors on pancreatic islets of fa/fa Zucker rats
No full textRecently, a defect in pertussis toxin-independent actions of epinephrine on pancreatic B-cells of fa/fa Zucker rats was reported (Cawthorn and Chan (1991) Mol. Cell. Endocrinol. 75, 197-204). We now report studies of islet alpha 2-adrenoceptor function of fa/fa rats. Insulin and cAMP production by islets of obese rats were both inhibited by the alpha 2-adrenoceptor agonist clonidine. Calculated pD2 values for clonidine were 9.57 +/- 0.59 and 9.43 +/- 0.33 for lean and fa/fa rat islets, respectively. Yohimbine reversed clonidine effects equipotently in lean and obese rat islets (pA2 values of 7.48 +/- 0.57 vs 7.43 +/- 0.58). Unexpectedly, the alpha 1-antagonist prazosin stimulated insulin secretion from islets of obese but not lean rats. Functional characteristics of the alpha-adrenoceptors on fa/fa islets are thus similar to those recently designated alpha 2B. Altered expression of alpha-adrenoceptors on pancreatic islets of fa/fa rats may contribute to changes in the pertussis toxin-independent pathway of epinephrine action previously observed.LR: 20061115; PUBM: Print; JID: 7500844; 0 (Receptors, Adrenergic, alpha); 11061-68-0 (Insulin); 146-48-5 (Yohimbine); 19216-56-9 (Prazosin); 4205-90-7 (Clonidine); 50-99-7 (Glucose); 51-43-4 (Epinephrine); 60-92-4 (Cyclic AMP); 66428-89-5 (Forskolin); ppublishSource type: Electronic(1
Glucose refractoriness of beta-cells from fed fa/fa rats is ameliorated by nonesterified fatty acids
No full textThe aim of this study was to characterize the glucose responsiveness of individual beta-cells from fa/fa rats under ad libitum feeding conditions. Enlarged intact islets from fed fa/fa rats had a compressed insulin response curve to glucose compared with smaller islets. Size-sorted islets from obese rats yielded beta-cells whose glucose responsiveness was assessed by reverse hemolytic plaque assay to determine whether glucose refractoriness was caused by a decreased number of responsive cells or output per cell. In addition, the effects of palmitic acid on glucose-stimulated insulin secretion were assessed because of evidence that nonesterified fatty acids have acute beneficial effects. Two- to threefold more beta-cells from >250 microm diameter (large) islets than 10-fold increase in recruitment of active cells from small islets, compared with only a 2.6-fold increase in large islets. This refractoriness was partially reversed by preincubation of the cells in low glucose for 2 h. In addition, secretion per cell of the large islet beta-cell population was significantly reduced compared with lean beta-cells, so that the overall response capacity of large but not small islet beta-cells was significantly reduced at high glucose. Therefore, continued near-normal function of the beta-cells from small islets of fa/fa rats seems crucial for glucose responsiveness. Incubation of beta-cells from large islets with palmitic acid normalized the secretory capacity to glucose mainly by increasing recruitment and secondarily by increasing secretion per cell. In conclusion, these studies demonstrate refractoriness to glucose of beta-cells from large islets of fa/fa rats under ad libitum feeding conditions. When acutely exposed to nonesterified fatty acids, islets from fa/fa rats have a potentiated insulin response despite chronic elevation of plasma lipids in vivo.LR: 20061115; PUBM: Print; JID: 0372712; 0 (Fatty Acids, Nonesterified); 0 (Lipids); 11061-68-0 (Insulin); 50-99-7 (Glucose); 57-10-3 (Palmitic Acid); ppublishSource type: Electronic(1
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