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Physical Exercise Introduced After Weaning Enhances Pancreatic Islet Responsiveness To Glucose And Potentiating Agents In Adult Msg-obese Rats
No full textPhysical exercise represents an alternative way to prevent and/or ameliorate chronic metabolic diseases. Disruption of sympathetic nervous system (SNS) activity contributes to adiposity in obese subjects. Here, we verified the preventive effect of swimming training upon adiposity, adrenal catecholamine storage, and pancreatic islet function in obese monosodium glutamate (MSG)-treated rats. Male neonatal Wistar rats received MSG (4 mg/g body weight) during the first 5 days of life and, at weaning, half of the rats were submitted to swimming training, 30 min/day, 3 days a week, until 90 days of age (exercised rats: MSGex). Half of the rats were used as controls (sedentary group, MSGsd). Exercise training (ET) decreased insulinemia and fat deposition in MSGex, and increased adrenal catecholamine content, compared with MSGsd rats. Insulinemia during the ivGTT was lower in MSGex rats, despite a lack of difference in glycemia. Swimming training enhanced insulin release in islets challenged by 2.8-8.3 mmol/l glucose, whereas, at supraphysiological glucose concentrations (11.1-16.7 mmol/l), MSGex islets secreted less insulin than MSGsd. No differences in insulin secretion were observed following l-arginine (Arg) or K+ stimuli. In contrast, islets from MSGex rats secreted more insulin when exposed to carbachol (100 μmol/l), forskolin (10 μmol/l), or IBMX (1 mmol/l) at 8.3 mmol/l glucose. Additionally, MSGex islets presented a better epinephrine inhibition upon insulin release. These results demonstrate that ET prevented the onset of obesity in MSG rats, probably by enhancing adrenal catecholamine levels. ET ameliorates islet responsiveness to several compounds, as well as insulin peripheral action. © Georg Thieme Verlag KG Stuttgart · New York.469609614Arrone, L.J., Mackintosh, R., Rosenbaum, M., Leibel, R.L., Hirsch, J., Cardiac autonomic nervous system activity in obese and never-obese young men (1997) Obes Res, 5, pp. 354-359Kahn, S.E., Prigeon, R.L., Schwartz, R.S., Fujimoto, W.Y., Knopp, R.H., Brunzell, J.D., Porte Jr., D., Obesity, body fat distribution, insulin sensitivity and Islet beta-cell function as explanations for metabolic diversity (2001) J Nutr, 131, pp. 354S-360SKahn, S.E., The relative contributions of insulin resistance and beta-cell dysfunction to the pathophysiology of Type 2 diabetes (2003) Diabetologia, 46, pp. 3-19Bray, G.A., York, D.A., Hypothalamic and genetic obesity in experimental animals: An autonomic and endocrine hypothesis (1979) Physiol Rev, 59, pp. 719-809Bray, G.A., York, D.A., The MONA LISA hypothesis in the time of leptin (1998) Recent Prog Horm Res, 53, pp. 95-117. , discussion 117-118Scomparin, D.X., Gomes, R.M., Grassiolli, S., Rinaldi, W., Martins, A.G., De Oliveira, J.C., Gravena, C., De Freitas Mathias, P.C., Autonomic activity and glycemic homeostasis are maintained by precocious and low intensity training exercises in MSG-programmed obese mice (2009) Endocrine, 36, pp. 510-517Atef, N., Ktorza, A., Picon, L., Penicaud, L., Increased islet blood flow in obese rats: Role of the autonomic nervous system (1992) Am J Physiol, 262, pp. E736-E740Leigh, F.S., Kaufman, L.N., Young, J.B., Diminished epinephrine excretion in genetically obese (ob/ob) mice and monosodium glutamate-treated rats (1992) Int J Obes Relat Metab Disord, 16, pp. 597-604Weyer, C., Salbe, A.D., Lindsay, R.S., Pratley, R.E., Bogardus, C., Tataranni, P.A., Exaggerated pancreatic polypeptide secretion in Pima Indians: Can an increased parasympathetic drive to the pancreas contribute to hyperinsulinemia, obesity, and diabetes in humans (2001) Metabolism, 50, pp. 223-230Quilliot, D., Zannad, F., Ziegler, O., Impaired response of cardiac autonomic nervous system to glucose load in severe obesity (2005) Metabolism, 54, pp. 966-974Inoue, S., Bray, G.A., The effects of subdiaphragmatic vagotomy in rats with ventromedial hypothalamic obesity (1977) Endocrinology, 100, pp. 108-114Edvell, A., Lindstrom, P., Vagotomy in young obese hyperglycemic mice: Effects on syndrome development and islet proliferation (1998) Am J Physiol, 274, pp. E1034-E1039Balbo, S.L., Mathias, P.C., Bonfleur, M.L., Alves, H.F., Siroti, F.J., Monteiro, O.G., Ribeiro, F.B., Souza, A.C., Vagotomy reduces obesity in MSG-treated rats (2000) Res Commun Mol Pathol Pharmacol, 108, pp. 291-296Balbo, S.L., Grassiolli, S., Ribeiro, R.A., Bonfleur, M.L., Gravena, C., Brito Mdo, N., Andreazzi, A.E., Torrezan, R., Fat storage is partially dependent on vagal activity and insulin secretion of hypothalamic obese rat (2007) Endocrine, 31, pp. 142-148Scheurink, A.J., Steffens, A.B., Roossien, B., Balkan, B., Sympathoadrenal function in genetically obese Zucker rats (1992) Physiol Behav, 52, pp. 679-685Barnard, R.J., Wen, S.J., Exercise and diet in the prevention and control of the metabolic syndrome (1994) Sports Med, 18, pp. 218-228Olney, J.W., Brain lesions, obesity, and other disturbances in mice treated with monosodium glutamate (1969) Science, 164, pp. 719-721Olney, J.W., Glutamate-induced neuronal necrosis in the infant mouse hypothalamus. An electron microscopic study (1971) J Neuropathol Exp Neurol, 30, pp. 75-90Martins, A.C., Souza, K.L., Shio, M.T., Mathias, P.C., Lelkes, P.I., Garcia, R.M., Adrenal medullary function and expression of catecholamine-synthesizing enzymes in mice with hypothalamic obesity (2004) Life Sci, 74, pp. 3211-3222Nardelli, T.R., Ribeiro, R.A., Balbo, S.L., Vanzela, E.C., Carneiro, E.M., Boschero, A.C., Bonfleur, M.L., Taurine prevents fat deposition and ameliorates plasma lipid profile in monosodium glutamate-obese rats (2011) Amino Acids, 41, pp. 901-908Ribeiro, R.A., Balbo, S.L., Roma, L.P., Camargo, R.L., Barella, L.F., Vanzela, E.C., Carneiro, E.M., Bonfleur, M.L., Impaired muscarinic type 3 (M3) receptor/PKC and PKA pathways in islets form MSG-obese rats (2013) Mol Biol Rep, 40, pp. 4521-4528Scomparin, D.X., Grassiolli, S., Marcal, A.C., Gravena, C., Andreazzi, A.E., Mathias, P.C., Swim training applied at early age is critical to adrenal medulla catecholamine content and to attenuate 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Taurine Prevents Fat Deposition And Ameliorates Plasma Lipid Profile In Monosodium Glutamate-obese Rats
No full textThe aim of the present study was to evaluate the preventive effects of taurine (TAU) supplementation upon monosodium glutamate (MSG)-induced obesity. Rats treated during the first 5 days of life with MSG or saline were distributed into the following groups: control (CTL), CTL-treated with TAU (CTAU), MSG and MSG-supplemented with TAU (MTAU). CTAU and MTAU received 2.5% of TAU in their drinking water from 21 to 90 days of life. At the end of treatment, MSG and MTAU rats were hyperinsulinemic, glucose intolerant and insulin resistant, as judged by the HOMA index. MSG and MTAU rat islets secreted more insulin at 16.7 mM glucose compared to CTL. MSG rats also showed higher triglycerides (TG) and non-esterified fatty acids (NEFA) plasma levels, Lee Index, retroperitoneal and periepidydimal fat pads, compared with CTL, whereas plasma lipid concentrations and fat depots were lower in MTAU, compared with MSG rats. In addition, MSG rats had a higher liver TG content compared with CTL. TAU decreased liver TG content in both supplemented groups, but fat content only in MTAU rats. TAU supplementation did not change glucose homeostasis, insulin secretion and action, but reduced plasma and liver lipid levels in MSG rats. © Springer-Verlag 2010.414901908Anuradha, C.V., Balakrishnan, S.D., Taurine attenuates hypertension and improves insulin sensitivity in the fructose-fed rat: An animal model of insulin resistance (1999) Can J Physiol Pharmacol, 77, pp. 749-754Balbo, S.L., Mathias, P.C., Bonfleur, M.L., Alves, H.F., Siroti, F.J., Monteiro, O.G., Ribeiro, F.B., Souza, A.C., Vagotomy reduces obesity in MSG-treated rats (2000) Res Commun Mol Pathol Pharmacol, 108, pp. 291-296Balbo, S.L., Grassiolli, S., Ribeiro, R.A., Bonfleur, M.L., Gravena, C., Brito Mdo, N., Andreazzi, A.E., Torrezan, R., Fat storage is partially dependent on vagal activity and insulin secretion of hypothalamic obese rat (2007) Endocrine, 31, pp. 142-148Bernardis, L.L., Patterson, B.D., Correlation between 'Lee index' and carcass fat content in weanling and adult female rats with hypothalamic 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a high-cholesterol diet (2004) Life Sci, 74, pp. 1889-1898Cherif, H., Reusens, B., Dahri, S., Remacle, C., Hoet, J.J., Stimulatory effects of taurine on insulin secretion by fetal rat islets cultured in vitro (1996) J Endocrinol, 151, pp. 501-506Cherif, H., Reusens, B., Ahn, M.T., Hoet, J.J., Remacle, C., Effects of taurine on the insulin secretion of rat fetal islets from dams fed a low-protein diet (1998) J Endocrinol, 159, pp. 341-348Choi, M.J., Kim, J.H., Chang, K.J., The effect of dietary taurine supplementation on plasma and liver lipid concentrations and free amino acid concentrations in rats fed a high-cholesterol diet (2006) Adv Exp Med Biol, 583, pp. 235-242Dashti, N., The effect of low density lipoproteins, cholesterol, and 25-hydroxycholesterol on apolipoprotein B gene expression in HepG2 cells (1992) J Biol Chem, 267, pp. 7160-7169Dawson Jr., R., Acute and long lasting neurochemical effects of monosodium glutamate administration to mice (1983) Neuropharmacology, 22, pp. 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Karabay, G., Zagyapan, R.D., Ozer, C., Sayan, H., Duyar, I., Effects of taurine in glucose and taurine administration (2004) Amino Acids, 27, pp. 327-333Kulakowski, E.C., Maturo, J., Hypoglycemic properties of taurine: Not mediated by enhanced insulin release (1984) Biochem Pharmacol, 33, pp. 2835-2838Macho, L., Fickova, M., Jezova Zorad, S., Late effects of postnatal administration of monosodium glutamate on insulin action in adult rats (2000) Physiol Res, 49 (1 SUPPL.), pp. S79-S85Martins, A.C., Souza, K.L., Shio, M.T., Mathias, P.C., Lelkes, P.I., Garcia, R.M., Adrenal medullary function and expression of catecholamine- synthesizing enzymes in mice with hypothalamic obesity (2004) Life Sci, 74, pp. 3211-3222Matthews, D.R., Hosker, J.P., Rudenski, A.S., Naylor, B.A., Treacher, D.F., Turner, R.C., Homeostasis model assessment: Insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man (1985) Diabetologia, 28, pp. 412-419Maturo, J., 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Thirunavukkarasu, V., Anuradha, C.V., Taurine modifies insulin signaling enzymes in the fructose-fed insulin resistant rats (2005) Diabetes Metab, 31, pp. 337-344Nishimura, N., Umeda, C., Ona, H., Yokogoshi, H., The effect of taurine on plasma cholesterol concentration in genetic type 2 diabetic GK rats (2002) J Nutr Sci Vitaminol (Tokyo, 48, pp. 483-490Olney, J.W., Brain lesions, obesity, and other disturbances in mice treated with monosodium glutamate (1969) Science, 164, pp. 719-721Olney, J.W., Glutamate-induced neuronal necrosis in the infant mouse hypothalamus. An electron microscopic study (1971) J Neuropathol Exp Neurol, 30, pp. 75-90Olofsson, S.O., Boren, J., Apolipoprotein B: A clinically important apolipoprotein which assembles atherogenic lipoproteins and promotes the development of atherosclerosis (2005) J Intern Med, 258, pp. 395-410Ribeiro, R.A., Bonfleur, M.L., Amaral, A.G., Vanzela, E.C., Rocco, S.A., Boschero, A.C., Carneiro, E.M., Taurine supplementation enhances nutrient-induced insulin secretion in pancreatic mice islets (2009) Diabetes Metab Res Rev, 25, pp. 370-379Ribeiro, R.A., Vanzela, E.C., Oliveira, C.A., Bonfleur, M.L., Boschero, A.C., Carneiro, E.M., Taurine supplementation: Involvement of cholinergic/phospholipase C and protein kinase A pathways in potentiation of insulin secretion and Ca2+ handling in mouse pancreatic islets (2010) Br J Nutr, 104 (8), pp. 1148-1155Tas, S., Sarandol, E., Ayvalik, S.Z., Serdar, Z., Dirican, M., Vanadyl sulfate, taurine, and combined vanadyl sulfate and taurine treatments in diabetic rats: Effects on the oxidative and antioxidative systems (2007) Arch Med Res, 38, pp. 276-283Tsuboyama-Kasaoka, N., Shozawa, C., Sano, K., Kamei, Y., Kasaoka, S., Hosokawa, Y., Ezaki, O., Taurine (2-aminoethanesulfonic acid) deficiency creates a vicious circle promoting obesity (2006) Endocrinology, 147, pp. 3276-3284Xiao, C., Giacca, A., Lewis, G.F., Oral taurine but not N-acetylcysteine ameliorates NEFA-induced impairment in insulin sensitivity and beta cell function in obese and overweight, non-diabetic men (2008) Diabetologia, 51, pp. 139-146Yanagita, T., Han, S.Y., Hu, Y., Nagao, K., Kitajima, H., Murakami, S., Taurine reduces the secretion of apolipoprotein B100 and lipids in HepG2 cells (2008) Lipids Health Dis, 7, p. 38Zhang, M., Bi, L.F., Fang, J.H., Su, X.L., Da, G.L., Kuwamori, T., Kagamimori, S., Beneficial effects of taurine on serum lipids in overweight or obese non-diabetic subjects (2004) Amino Acids, 26, pp. 267-27
Impaired Muscarinic Type 3 (m3) Receptor/pkc And Pka Pathways In Islets From Msg-obese Rats
No full textMonosodium glutamate-obese rats are glucose intolerant and insulin resistant. Their pancreatic islets secrete more insulin at increasing glucose concentrations, despite the possible imbalance in the autonomic nervous system of these rats. Here, we investigate the involvement of the cholinergic/protein kinase (PK)-C and PKA pathways in MSG β-cell function. Male newborn Wistar rats received a subcutaneous injection of MSG (4 g/kg body weight (BW)) or hyperosmotic saline solution during the first 5 days of life. At 90 days of life, plasma parameters, islet static insulin secretion and protein expression were analyzed. Monosodium glutamate rats presented lower body weight and decreased nasoanal length, but had higher body fat depots, glucose intolerance, hyperinsulinemia and hypertrigliceridemia. Their pancreatic islets secreted more insulin in the presence of increasing glucose concentrations with no modifications in the islet-protein content of the glucose-sensing proteins: the glucose transporter (GLUT)-2 and glycokinase. However, MSG islets presented a lower secretory capacity at 40 mM K+ (P < 0.05). The MSG group also released less insulin in response to 100 μM carbachol, 10 μM forskolin and 1 mM 3-isobutyl-1-methyl-xantine (P < 0.05, P < 0.0001 and P < 0.01). These effects may be associated with a the decrease of 46 % in the acetylcholine muscarinic type 3 (M3) receptor, and a reduction of 64 % in PKCα and 36 % in PKAα protein expressions in MSG islets. Our data suggest that MSG islets, whilst showing a compensatory increase in glucose-induced insulin release, demonstrate decreased islet M3/PKC and adenylate cyclase/PKA activation, possibly predisposing these prediabetic rodents to the early development of β-cell dysfunction. © 2013 Springer Science+Business Media Dordrecht.40745214528Tengholm, A., Gylfe, E., Oscillatory control of insulin secretion (2009) Mol Cell Endocrinol, 297 (1-2), pp. 58-72. , 18706473 10.1016/j.mce.2008.07.009 1:CAS:528:DC%2BD1cXhsFajt7rNCnop, M., Welsh, N., Jonas, J.C., Jorns, A., Lenzen, S., Eizirik, D.L., Mechanisms of pancreatic beta-cell death in type 1 and type 2 diabetes: Many differences, few similarities (2005) Diabetes, 54 (SUPPL. 2), pp. 97-S107. , 16306347 10.2337/diabetes.54.suppl-2.S97 1:CAS:528:DC%2BD2MXht12gs7nFRibeiro, R.A., Santos-Silva, J.C., Vettorazzi, J.F., Cotrim, B.B., Mobiolli, D.D., Boschero, A.C., Carneiro, E.M., Taurine supplementation prevents morpho-physiological alterations in high-fat diet mice pancreatic beta-cells (2012) Amino Acids, 43 (4), pp. 1791-1801. , 22418865 10.1007/s00726-012-1263-5 1:CAS:528:DC%2BC38XhtlOls77NAhren, B., Autonomic regulation of islet hormone secretion-implications for health and disease (2000) Diabetologia, 43 (4), pp. 393-410. , 10819232 10.1007/s001250051322 1:CAS:528:DC%2BD3cXit12hsLk%3DOlney, J.W., Sharpe, L.G., Brain lesions in an infant rhesus monkey treated with monsodium glutamate (1969) Science, 166 (3903), pp. 386-388. , 5812037 10.1126/science.166.3903.386 1:CAS:528:DyaE3cXhtFSrtw%3D%3DMaiter, D., Underwood, L.E., Martin, J.B., Koenig, J.I., Neonatal treatment with monosodium glutamate: Effects of prolonged growth hormone (GH)-releasing hormone deficiency on pulsatile GH secretion and growth in female rats (1991) Endocrinology, 128 (2), pp. 1100-1106. , 1989848 10.1210/endo-128-2-1100 1:CAS:528:DyaK3MXpvFentg%3D%3DMartins, A.C., Souza, K.L., Shio, M.T., Mathias, P.C., Lelkes, P.I., Garcia, R.M., Adrenal medullary 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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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