21 research outputs found

    Application of neural networks: a molecular geometry optimization study

    No full text

    Early Onset Of Obesity Induces Reproductive Deficits In Female Rats

    No full text
    The incidence of obesity is increasing rapidly all over the world and results in numerous health detriments, including disruptions in reproduction. However, the mechanisms by which excess body fat interferes with reproductive functions are still not fully understood. After weaning, female rats were treated with a cafeteria diet or a chow diet (control group). Biometric and metabolic parameters were evaluated in adulthood. Reproductive parameters, including estradiol, progesterone, LH and prolactin during the proestrus afternoon, sexual behavior, ovulation rates and histological analysis of ovaries were also evaluated. Cafeteria diet was able to induce obesity in female rats by increasing body and fat pad weight, which resulted in increased levels of triglycerides, total cholesterol, LDL and induced insulin resistance. The cafeteria diet also negatively affected female reproduction by reducing the number of oocytes and preantral follicles, as well as the thickness of the follicular layer. Obese females did not show preovulatory progesterone and LH surges, though plasma estradiol and prolactin showed preovulatory surges similar to control rats. Nevertheless, sexual receptiveness was not altered by cafeteria diet. Taken together, our results suggest that the cafeteria diet administered from weaning age was able to induce obesity and reduce the reproductive capability in adult female rats, indicating that this obesity model can be used to better understand the mechanisms underlying reproductive dysfunction in obese subjects. © 2012 Elsevier Inc.105511041111Spiegelman, B.M., Flier, J.S., Obesity and the regulation of energy balance (2001) Cell, 104, pp. 531-543Mayes, J.S., Watson, G.H., Direct effects of sex steroids hormones on adipose tissues and obesity (2004) Obes Rev, 5, pp. 197-216Rogers, J., Mitchell, G.W., The relation of obesity to menstrual disturbances (1952) N Engl J Med, 247 (2), pp. 53-55Pasquali, R., Casimirri, F., The impact of obesity on hyperandrogenism and polycystic ovary syndrome in premenopausal women (1993) Clin Endocrinol, 39 (1), pp. 1-16Tortoriello, D.V., McMinn, J., Chua, S.C., Dietary-induced obesity and hypothalamic infertility in female DBA/2J mice (2004) Endocrinology, 45 (3), pp. 1238-1247Hall, L.F., Neubert, A.G., Obesity and pregnancy (2005) Obstet Gynecol Surv, 60 (4), pp. 253-260Brannian, J.D., Furman, G.M., Diggins, M., Declining fertility in the lethal yellow mouse is related to progressive hyperleptinemia and leptin resistance (2005) Reprod Nutr Dev, 45 (2), pp. 143-150Rittmaster, R.S., Desewal, M., Lehman, L., The role of adrenal hyperandrogenism, insulin resistance, and obesity in the pathogenesis of polycystic ovarian syndrome (1993) J Clin Endocrinol Metab, 76, pp. 1295-1300Douchi, T., Kuwahata, R., Yamamoto, S., Oki, T., Yamasaki, H., Nagata, Y., Relationship of upper obesity to menstrual disorders (2002) Acta Obstet Gynecol Scand, 81, pp. 147-150Chopra, M., Galbraith, S., Damton-Hill, I., A global response to a global problem: the epidemic of overnutrition (2002) Bull World Health Organ, 80 (12), pp. 952-958Yura, S., Ogawa, Y., Sagawa, N., Masuzaki, H., Itoh, H., Ebihara, K., Accelerated puberty and late-onset hypothalamic hypogonadism in female transgenic skinny mice overexpressing leptin (2000) J Clin Invest, 105 (6), pp. 749-755Lake, J.K., Power, C., Cole, T.J., Women's reproductive health: the role of body mass index in early and adult life (1997) Int J Obes Relat Metab Disord, 21 (6), pp. 432-438Prada, P.O., Zecchin, H.G., Gasparetti, A.L., Torsoni, M.A., Ueno, M., Hirata, A.E., Western diet modulates insulin signaling, c-Jun N-terminal kinase activity, and insulin receptor substrate-1ser307 phosphorylation in a tissue-specific fashion (2005) Endocrinology, 146 (3), pp. 1576-1587Freeman, M.E., The neuroendocrine control of the ovarian cycle of the rat (1994) Physiology of reproduction, 45, pp. 613-658. , Raven Press, New York, E. Knobil, Neill (Eds.)Gomes, C.M., Raineki, C., Ramos de Paula, P., Severino, G.S., Helena, C.V., Anselmo-Franci, J.A., Neonatal handling and reproductive function in female rats (2005) J Endocrinol, 184 (2), pp. 435-445Sodersten, P., Hansen, S., Effects of oestradiol and progesterone on the induction and duration of sexual receptivity in cyclic female rats (1977) J Endocrinol, 74 (3), pp. 477-485Pfaus, J.G., Shadiack, A., Van Soest, T., Tse, M., Molinoff, P., Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist (2004) Proc Natl Acad Sci U S A, 101 (27), pp. 10201-10204Poletini, M.O., Szawka, R.E., Freitas Marcon, R.M., Veiga, M.D., Franci, C.R., Anselmo-Franci, J.A., A method to study preovulatory surges of gonadotropins (2003) Brain Res Brain Res Protoc, 12 (1), pp. 41-48. , Endocrinology 146(3): 1576-1587Harms, P.G., Ojeda, S.R., A rapid and simple procedure for chronic cannulation of the rat jugular vein (1974) J Appl Physiol, 36 (3), pp. 391-392Matthews, 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 (7), pp. 412-419Lara, H.E., Dissen, G.A., Leyton, V., Paredes, A., Fuenzalida, H., Fieldler, J.L., An increased intraovarian synthesis of nerve growth factor and its low affinity receptor is a principal component of steroid-induced polycystic ovary in the rat (2000) Endocrinology, 141 (3), pp. 1059-1072Richards, J.S., Maturation of ovarian follicles: actions and interactions of pituitary and ovarian hormones on follicular cell differentiation (1980) Physiol Rev, 60 (1), pp. 51-89Bao, B., Kumar, N., Karp, R.M., Garverick, H.A., Sundaram, K., Estrogen receptor-beta expression in relation to the expression of luteinizing hormone receptor and cytochrome P450 enzymes in rat ovarian follicles (2000) Biol Reprod, 63 (6), pp. 1747-1755Micevych, P., Sinchak, K., Mills, R.H., Tao, L., LaPolt, P., Lu, J.K., The luteinizing hormone surge is preceded by an estrogen-induced increase of hypothalamic progesterone in ovariectomized and adrenalectomized rats (2003) Neuroendocrinology, 78 (1), pp. 29-35Wildt, L., Hausler, A., Hutchison, J.S., Marshall, G., Knobil, E., Estradiol as a gonadotropin releasing hormone in the rhesus monkey (1981) Endocrinology, 108 (5), pp. 2011-2013Moenter, S.M., Caraty, A., Karsch, F.J., The estradiol-induced surge of gonadotropin-releasing hormone in the ewe (1990) Endocrinology, 127 (3), pp. 1375-1384Freeman, M.E., Kanyicska, B., Lerant, A., Nagy, G., Prolactin: structure, function, and regulation of secretion (2000) Physiol Rev, 80 (4), pp. 1523-1631. , ReviewMcNatty, K.P., Sawers, R.S., McNeilly, A.S., A possible role for prolactin in control of steroid secretion by the human Graafian follicle (1974) Nature, 250 (5468), pp. 653-655Uilenbroek, J.T., van der Schoot, P., den Besten, D., Lankhorst, R.R., A possible direct effect of prolactin on follicular activity (1982) Biol Reprod, 27 (5), pp. 1119-1125Oktem, O., Oktay, K., The ovary: anatomy and function throughout human life (2008) Ann N Y Acad Sci, 1127, pp. 1-9. , ReviewMattioli, M., Barboni, B., Turriani, M., Galeati, G., Zannoni, A., Castellani, G., Follicle activation involves vascular endothelial growth factor production and increased blood vessel extension (2001) Biol Reprod, 65 (4), pp. 1014-1019Kretschmer, B.D., Schelling, P., Beier, N., Liebscher, C., Treutel, S., Krüger, N., Modulatory role of food, feeding regime and physical exercise on body weight and insulin resistance (2005) Life Sci, 76 (14), pp. 1553-1573Fried, S.K., Rao, S.P., Sugars, hypertriglyceridemia, and cardiovascular disease (2003) Am J Clin Nutr, 78 (4), pp. 873S-880SMortola, J.F., Sathanandan, M., Pavlou, S., Dahl, K.D., Hsueh, A.J., Rivier, J., Suppression of bioactive and immunoreactive follicle-stimulating hormone and luteinizing hormone levels by a potent gonadotropin-releasing hormone antagonist: pharmacodynamic studies (1989) Fertil Steril, 51 (6), pp. 957-963Poretsky, L., Cataldo, N.A., Rosenwaks, Z., Giudice, L.C., The insulin-related ovarian regulatory system in health and disease (1999) Endocr Rev, 20 (4), pp. 535-582Billig, H., Furuta, I., Hsueh, A.J., Estrogens inhibit and androgens enhance ovarian granulosa cell apoptosis (1993) Endocrinology, 133 (5), pp. 2204-2212Willis, D., Mason, H., Gilling-Smith, C., Franks, S., Modulation by insulin of follicle-stimulating hormone and luteinizing hormone actions in human granulosa cells of normal and polycystic ovaries (1996) J Clin Endocrinol Metab, 81 (1), pp. 302-309Brüning, J.C., Gautam, D., Burks, D.J., Gillette, J., Schubert, M., Orban, P.C., Role of brain insulin receptor in control of body weight and reproduction (2000) Science, 289 (5487), pp. 2122-2125Gosman, G.G., Katcher, H.I., Legro, R.S., Obesity and the role of gut and adipose hormones in female reproduction (2006) Hum Reprod Update, 12 (5), pp. 585-601. , ReviewMaffei, M., Halaas, J., Ravussin, E., Pratley, R.E., Lee, G.H., Zhang, Y., Leptin levels in human and rodent: measurement of plasma leptin and ob RNA in obese and weight-reduced subjects (1995) Nat Med, 11, pp. 1155-1161Moschos, S., Chan, J.L., Mantzoros, C.S., Leptin and reproduction: a review (2002) Fertil Steril, 77 (3), pp. 433-444. , ReviewBajari, T.M., Nimpf, J., Schneider, W.J., Role of leptin in reproduction (2004) Curr Opin Lipidol, 15 (3), pp. 315-319. , ReviewDuggal, P.S., Van Der Hoek, K.H., Milner, C.R., Ryan, N.K., Armstrong, D.T., Magoffin, D.A., The in vivo and in vitro effects of exogenous leptin on ovulation in the rat (2000) Endocrinology, 141 (6), pp. 1971-1976Spicer, L.J., Francisco, C.C., The adipose obese gene product, leptin: evidence of a direct inhibitory role in ovarian function (1997) Endocrinology, 138 (8), pp. 3374-3379Agarwal, S.K., Vogel, K., Weitsman, S.R., Magoffin, D.A., Leptin antagonizes the insulin-like growth factor-I augmentation of steroidogenesis in granulosa and theca cells of the human ovary (1999) J Clin Endocrinol Metab, 84 (3), pp. 1072-1076Pasquali, R., Gambineri, A., Polycystic ovary syndrome: a multifaceted disease from adolescence to adult age (2006) Ann N Y Acad Sci, 1092, pp. 158-174. , ReviewSaigal, C.S., Obesity and erectile dysfunction: common problems, common solution? (2004) JAMA, 291 (24), pp. 3011-3012Esposito, K., Di Palo, C.C., Marfella, R., Giugliano, D., The effect of weight loss on endothelial functions in obesity: response to Sciacqua et al (2003) Diab Care, 26 (10), pp. 2968-2969Kolotkin, R.L., Binks, M., Crosby, R.D., Østbye, T., Gress, R.E., Adams, T.D., Obesity and sexual quality of life (2006) Obesity (Silver Spring), 14 (3), pp. 472-479Bajos, N., Wellings, K., Laborde, C., Moreau, C., Sexuality and obesity, a gender perspective: results from French national random probability survey of sexual behaviours (2010) BMJ, 340, pp. c2573. , CSF GroupKarkanias, G.B., Morales, J.C., Li, C.S., Deficits in reproductive behavior in diabetic female rats are due to hypoinsulinemia rather than hyperglycemia (1997) Horm Behav, 32 (1), pp. 19-29Levi, J.E., Weinberg, T., Pregnancy in alloxan diabetic rats (1949) Proc Soc Exp Biol Med, 72 (3), pp. 658-662McEwen, B.S., Neural gonadal steroid actions (1981) Science, 211 (4488), pp. 1303-1311. , ReviewEtgen, A.M., Chu, H.P., Fiber, J.M., Karkanias, G.B., Morales, J.M., Hormonal integration of neurochemical and sensory signals governing female reproductive behavior (1999) Behav Brain Res, 105 (1), pp. 93-103Mathews, D., Edwards, D.A., The ventromedial nucleus of the hypothalamus and the hormonal arousal of sexual behaviors in the female rat (1977) Horm Behav, 8 (1), pp. 40-51Pleim, E.T., Brown, T.J., MacLusky, N.J., Etgen, A.M., Barfield, R.J., Dilute estradiol implants and progestin receptor induction in the ventromedial nucleus of the hypothalamus: correlation with receptive behavior in female rats (1989) Endocrinology, 124 (4), pp. 1807-1812Auger, A.P., Ligand-independent activation of progestin receptors: relevance for female sexual behaviour (2001) Reproduction, 122 (6), pp. 847-855Flanagan-Cato, L.M., Calizo, L.H., Daniels, D., The synaptic organization of VMH neurons that mediate the effects of estrogen on sexual behavior (2001) Horm Behav, 40 (2), pp. 178-182Witcher, J.A., Freeman, M.E., The proestrus surge of prolactin enhances sexual receptivity in the rat (1985) Biol Reprod, 32 (4), pp. 834-83

    Decision support issues in automated driving systems

    No full text
    Machine learning and computational processing have advanced such that automated driving systems (ADSs) are no longer a distant reality. Many automobile manufacturers have developed prototypes; however, there exist numerous decision support issues requiring resolution to ensure mass ADS adoption. In the coming decades, it is likely that production ADSs will only be partially autonomous. Such ADSs operate within predetermined conditions and require driver intervention when they are violated. Since forecasts of their 20-year market penetration are relatively low, ADSs will likely operate in heterogeneous traffic characterized by vehicles of varying autonomy levels. Under these conditions, effective decision support must consider intangible, subjective, and emotional factors as well as influences of human cognition; otherwise, the ADS risks driver distrust and unsatisfactory performance based on an incomplete understanding of its environment. We survey the literature relevant to these issues, identify open problems, and propose research directions for their resolution.Peer reviewe

    Pronounced sequence specificity of the TET enzyme catalytic domain guides its cellular function

    No full text
    TET ten eleven translocation enzymes catalyze the oxidation of 5 methylcytosine bases in DNA, thus driving active and passive DNA demethylation. Here, we report that the catalytic domain of mammalian TET enzymes favor CGs embedded within basic helix loop helix and basic leucine zipper domain transcription factor binding sites, with up to 250 fold preference in vitro. Crystal structures and molecular dynamics calculations show that sequence preference is caused by intrasubstrate interactions and CG flanking sequence indirectly affecting enzyme conformation. TET sequence preferences are physiologically relevant as they explain the rates of DNA demethylation in TET rescue experiments in culture and in vivo within the zygote and germ line. Most and least favorable TET motifs represent DNA sites that are bound by methylation sensitive immediate early transcription factors and octamer binding transcription factor 4 OCT4 , respectively, illuminating TET function in transcriptional responses and pluripotency suppor

    Study of the Ground-State Geometry of Silicon Clusters Using Artificial Neural Networks

    No full text
    Theoretical determination of the ground-state geometry of Si clusters is a difficult task. As the number of local minima grows exponentially with the number of atoms, to find the global minimum is a real challenge. One may start the search procedure from a random distribution of atoms but it is probably wiser to make use of any available information to restrict the search space. Here, we introduce a new approach, the Assisted Genetic Optimization (AGO) that couples an Artificial Neural Network (ANN) to a Genetic Algorithm (GA). Using available information on small Silicon clusters, we trained an ANN to predict good starting points (initial population) for the GA. AGO is applied to Si10 and Si20 and compared to pure GA. Our results indicate: i) AGO is, at least, 5 times faster than pure GA in our test case; ii) ANN training can be made very fast and successfully plays the role of an experienced investigator; iii) AGO can easily be adapted to other optimization problems
    corecore