John Rg Challis

Summary

Affiliation: University of Toronto
Country: Canada

Publications

  1. ncbi request reprint The fetal placental hypothalamic-pituitary-adrenal (HPA) axis, parturition and post natal health
    J R Challis
    Department of Physiology, University of Toronto, 1 King s College Circle, Med Sciences, Building MSB 3205 7, Toronto, Ontario, Canada M5S 1A8
    Mol Cell Endocrinol 185:135-44. 2001
  2. ncbi request reprint Fetal signals and parturition
    John R G Challis
    Department of Physiology, University of Toronto, Canada
    J Obstet Gynaecol Res 31:492-9. 2005
  3. doi request reprint Fetal sex and preterm birth
    J Challis
    University of Toronto, Dept Obstetrics and Gynecology, Mount Sinai Hospital, Samuel Lunenfeld Research Institute, Toronto, ON, Canada
    Placenta 34:95-9. 2013
  4. doi request reprint SGI 2012: advances in reproductive health research
    John R G Challis
    Department of Physiology, University of Toronto, Toronto, ON, Canada
    Womens Health (Lond Engl) 8:363-5. 2012
  5. ncbi request reprint Prostaglandins and mechanisms of preterm birth
    John R G Challis
    Department of Physiology, CIHR Group in Fetal and Neonatal Health and Development, CIHR Institute of Human Development, Child and Youth Health, University of Toronto, Medical Sciences Building, Suite 3368, Toronto M5S 1A8, Canada
    Reproduction 124:1-17. 2002
  6. ncbi request reprint Understanding preterm labor
    J R Challis
    Department of Physiology, University of Toronto, CIHR Institute of Human Development, Child and Youth Health, Canada
    Ann N Y Acad Sci 943:225-34. 2001
  7. ncbi request reprint Endocrine and paracrine regulation of birth at term and preterm
    - Challis JRG
    Department of Physiology University of Toronto, Ontario, Canada
    Endocr Rev 21:514-50. 2000
  8. ncbi request reprint Fetal endocrine signals and preterm labor
    J R Challis
    Department of Obstetrics and Gynaecology, University of Cambridge, UK
    Biol Neonate 79:163-7. 2001
  9. ncbi request reprint Fetal hypothalamic-pituitary adrenal (HPA) development and activation as a determinant of the timing of birth, and of postnatal disease
    J Challis
    Department of Physiology, University of Toronto, Ontario, Canada
    Endocr Res 26:489-504. 2000
  10. ncbi request reprint Mechanism of parturition and preterm labor
    - Challis JRG
    Department of Physiology, University of Toronto, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Ontario, Canada
    Obstet Gynecol Surv 55:650-60. 2000

Collaborators

Detail Information

Publications44

  1. ncbi request reprint The fetal placental hypothalamic-pituitary-adrenal (HPA) axis, parturition and post natal health
    J R Challis
    Department of Physiology, University of Toronto, 1 King s College Circle, Med Sciences, Building MSB 3205 7, Toronto, Ontario, Canada M5S 1A8
    Mol Cell Endocrinol 185:135-44. 2001
    ..Thus, the level of fetal HPA activity is crucial not only for determining gestation length, but may also predict pathophysiologic adjustments in later life...
  2. ncbi request reprint Fetal signals and parturition
    John R G Challis
    Department of Physiology, University of Toronto, Canada
    J Obstet Gynaecol Res 31:492-9. 2005
  3. doi request reprint Fetal sex and preterm birth
    J Challis
    University of Toronto, Dept Obstetrics and Gynecology, Mount Sinai Hospital, Samuel Lunenfeld Research Institute, Toronto, ON, Canada
    Placenta 34:95-9. 2013
    ..These factors need consideration in studies of placental function and in the development of personalized strategies for the diagnosis of preterm labor and postnatal health...
  4. doi request reprint SGI 2012: advances in reproductive health research
    John R G Challis
    Department of Physiology, University of Toronto, Toronto, ON, Canada
    Womens Health (Lond Engl) 8:363-5. 2012
    ..The meeting was opened by the President of the Society for Gynecologic Investigation for 2011-2012, Stephen J Lye, from the University of Toronto (ON, Canada), with 13 past presidents of the society (including this writer) in attendance...
  5. ncbi request reprint Prostaglandins and mechanisms of preterm birth
    John R G Challis
    Department of Physiology, CIHR Group in Fetal and Neonatal Health and Development, CIHR Institute of Human Development, Child and Youth Health, University of Toronto, Medical Sciences Building, Suite 3368, Toronto M5S 1A8, Canada
    Reproduction 124:1-17. 2002
    ..In these circumstances, increased concentrations of maternal cortisol may cross into the fetal compartment, contributing to growth restriction and programming later life disease...
  6. ncbi request reprint Understanding preterm labor
    J R Challis
    Department of Physiology, University of Toronto, CIHR Institute of Human Development, Child and Youth Health, Canada
    Ann N Y Acad Sci 943:225-34. 2001
    ..These different mechanisms need to be considered in the development of strategies for the detection and management of the patient in preterm labor...
  7. ncbi request reprint Endocrine and paracrine regulation of birth at term and preterm
    - Challis JRG
    Department of Physiology University of Toronto, Ontario, Canada
    Endocr Rev 21:514-50. 2000
    ....
  8. ncbi request reprint Fetal endocrine signals and preterm labor
    J R Challis
    Department of Obstetrics and Gynaecology, University of Cambridge, UK
    Biol Neonate 79:163-7. 2001
    ..Other agents such as cytokines may intercede in this sequence to stimulate PGs and/or CRH, giving rise to a cascade phenomenon that results in preterm birth...
  9. ncbi request reprint Fetal hypothalamic-pituitary adrenal (HPA) development and activation as a determinant of the timing of birth, and of postnatal disease
    J Challis
    Department of Physiology, University of Toronto, Ontario, Canada
    Endocr Res 26:489-504. 2000
    ..We conclude that the level of fetal HPA activity is crucial not only for determining gestation length, but also predicts pathophysiologic adjustment in later life...
  10. ncbi request reprint Mechanism of parturition and preterm labor
    - Challis JRG
    Department of Physiology, University of Toronto, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Ontario, Canada
    Obstet Gynecol Surv 55:650-60. 2000
    ..This new information should facilitate development of improved methods of diagnosis and therapy for patients at risk of preterm labor...
  11. ncbi request reprint Identification and characterization of the protein-associated splicing factor as a negative co-regulator of the progesterone receptor
    Xuesen Dong
    Program in Development and Fetal Health, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
    J Biol Chem 280:13329-40. 2005
    ..Accordingly, we propose that PSF acts as a PR corepressor and contributes to the functional withdrawal of progesterone and the initiation of human labor...
  12. ncbi request reprint The effects of chorioamnionitis and betamethasone on 11beta hydroxysteroid dehydrogenase types 1 and 2 and the glucocorticoid receptor in preterm human placenta
    Jim F Johnstone
    Department of Physiology, University of Toronto, Toronto, Ontario, Canada
    J Soc Gynecol Investig 12:238-45. 2005
    ....
  13. ncbi request reprint Hepatic glucose regulation and metabolism in adult sheep: effects of prenatal betamethasone
    Deborah M Sloboda
    School of Women s and Infants Health, University of Western Australia, Perth, Australia
    Am J Physiol Endocrinol Metab 289:E721-8. 2005
    ..Prenatal betamethasone exposure results in elevated hepatic G-6-Pase activity in adulthood and may contribute to long-term changes in metabolism...
  14. ncbi request reprint Effect of pro-inflammatory cytokines on expression and activity of 11beta-hydroxysteroid dehydrogenase type 2 in cultured human term placental trophoblast and human choriocarcinoma JEG-3 cells
    Hiroshi Chisaka
    CIHR Group in Development and Fetal Health, Department of Physiology and Obstetrics, Gynecology and Medicine, University of Toronto, Toronto, Ontario, Canada
    J Soc Gynecol Investig 12:303-9. 2005
    ..Therefore, we have evaluated the effect of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) on 11beta-HSD2 in cultured human placental trophoblast and in human choriocarcinoma JEG-3 cells...
  15. ncbi request reprint Corticotropin-releasing hormone and urocortin induce secretion of matrix metalloproteinase-9 (MMP-9) without change in tissue inhibitors of MMP-1 by cultured cells from human placenta and fetal membranes
    Wei Li
    Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    J Clin Endocrinol Metab 90:6569-74. 2005
    ..CRH and urocortin (Ucn) are thought to play a central role in the mechanisms controlling human pregnancy and parturition...
  16. ncbi request reprint A cohort study found that white blood cell count and endocrine markers predicted preterm birth in symptomatic women
    M Karen Campbell
    Department of Epidemiology and Biostatistics, University of Western Ontario, Kresge Building, London, Ontario, Canada
    J Clin Epidemiol 58:304-10. 2005
    ..This cohort study investigated potential clinical and biochemical predictors of subsequent preterm birth in women presenting with threatened preterm labor...
  17. ncbi request reprint Prenatal betamethasone exposure results in pituitary-adrenal hyporesponsiveness in adult sheep
    Deborah M Sloboda
    Forrest Fetal Research Scientist, School of Women s and Infants Health, The Univ of Western Australia, King Edward Memorial Hospital, Subiaco, Western Australia, Australia
    Am J Physiol Endocrinol Metab 292:E61-70. 2007
    ..These data suggest that maternal, but not fetal, betamethasone administration results in adrenal suppression in adulthood...
  18. ncbi request reprint The role of prostaglandins in the mechanism of lipopolysaccharide-induced proMMP9 secretion from human placenta and fetal membrane cells
    Wei Li
    CIHR Group in Fetal Development and Health, Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    Biol Reprod 76:654-9. 2007
    ..There was no effect of LPS on TIMP1. Understanding this relationship may help in developing strategies for the prevention and management of pPROM and preterm labor...
  19. ncbi request reprint 15-Hydroxyprostaglandin dehydrogenase protein expression in human fetal membranes with and without subclinical inflammation
    Rose M Rizek
    Department of Obstetrics and Gynecology, University of Toronto and Mount Sinai Hospital, Toronto, Ontario, Canada
    Reprod Sci 14:260-9. 2007
    ..The differential expression of 55-kDa ir-PGDH in preterm amnion with and without PPROM supports the need for a better understanding of the different forms of PGDH...
  20. ncbi request reprint Maternal betamethasone administration reduces binucleate cell number and placental lactogen in sheep
    Thorsten Braun
    Department of Physiology and Obstetrics and Gynecology, University of Toronto, MSB, 1 King s College Circle, Toronto, Ontario, Canada
    J Endocrinol 194:337-47. 2007
    ..These data may suggest a placental role in growth restrictive effects of prenatal maternal BET exposure through alterations in placental output of oPL, a key metabolic hormone of pregnancy...
  21. ncbi request reprint 15-hydroxyprostaglandin dehydrogenase and cyclooxygenase 2 messenger ribonucleic acid expression and immunohistochemical localization in human cervical tissue during term and preterm labor
    Susanne Abelin Törnblom
    Department of Obstetrics and Gynecology, Karolinska Hospital and Karolinska Institute, SE 171 76 Stockholm, Sweden
    J Clin Endocrinol Metab 89:2909-15. 2004
    ..This observation indicates that both preterm and term cervical ripening is associated with decreased degradation of prostaglandins...
  22. doi request reprint Opposite effect of phorbol ester PMA on PTGS2 and PGDH mRNA expression in human chorion trophoblast cells
    Valentina Casciani
    Department of Physiology, University of Toronto, Toronto, Ontario, Canada
    Reprod Sci 15:40-50. 2008
    ..The authors conclude that upon stimulation with the same upstream signals, different downstream intracellular pathways regulate PTGS2 and PGDH mRNA expression...
  23. doi request reprint Prediction of preterm birth in symptomatic women using decision tree modeling for biomarkers
    Jacquelyn L Hill
    Department of Epidemiology and Biostatistics, The University of Western Ontario, London, ON, Canada
    Am J Obstet Gynecol 198:468.e1-7; discussion 468.e7-9. 2008
    ..The objective of the study was to use recursive partitioning (RP) to identify gestational age-specific and threshold values for infectious and endocrine biomarkers of imminent delivery...
  24. pmc Repeated betamethasone treatment of pregnant sheep programs persistent reductions in circulating IGF-I and IGF-binding proteins in progeny
    Kathryn L Gatford
    Research Centre for Early Origins of Adult Disease, Discipline of Obstetrics and Gynaecology, School of Paediatrics and Reproductive Health, University of Adelaide SA 5005, Australia
    Am J Physiol Endocrinol Metab 295:E170-8. 2008
    ..We conclude that repeated exposure to synthetic glucocorticoids in utero programs the IGF axis before and after birth, which may contribute to the adverse effects of betamethasone exposure on growth and metabolism...
  25. ncbi request reprint Maternal corticotropin-releasing hormone, fetal growth, and preterm birth
    John R G Challis
    Am J Obstet Gynecol 191:1059-60. 2004
  26. ncbi request reprint Effects of periconceptional undernutrition on the initiation of parturition in sheep
    Vasumathy Kumarasamy
    Liggins Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
    Am J Physiol Regul Integr Comp Physiol 288:R67-72. 2005
    ....
  27. ncbi request reprint Cortisol/progesterone antagonism in regulation of 15-hydroxysteroid dehydrogenase activity and mRNA levels in human chorion and placental trophoblast cells at term
    Falguni A Patel
    Canadian Institutes for Health Research Group in Fetal and Neonatal Health and Development, Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
    J Clin Endocrinol Metab 87:700-8. 2002
    ..In the presence of trilostane, P(4) at equimolar concentration to F reversed F inhibition of PGDH mRNA levels. These findings suggest that F may be acting as an endogenous inhibitor of P(4) action in the regulation of PGDH at term...
  28. ncbi request reprint Expression of matrix metalloproteinase (MMP)-2 and MMP-9 in human placenta and fetal membranes in relation to preterm and term labor
    Ping Xu
    CIHR Group in Fetal and Neonatal Health and Development and Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    J Clin Endocrinol Metab 87:1353-61. 2002
    ..An increase in MMP-9 expression may contribute to degradation of the ECM in the FM and PL, thereby facilitating FM rupture and PL detachment from the maternal uterus at labor, both preterm and term...
  29. ncbi request reprint Urocortin: a mechanism for the sustained activation of the HPA axis in the late-gestation ovine fetus?
    Alison C Holloway
    Department of Physiology, Canadian Institute for Health Research Groups in Fetal and Neonatal Health and Development, University of Toronto, Toronto, Ontario M55 1A8, Canada
    Am J Physiol Endocrinol Metab 283:E165-71. 2002
    ..Regulation of urocortin by cortisol suggests a mechanism to override negative feedback and sustain feedforward of fetal hypothalamic-pituitary-adrenal function, leading to birth...
  30. ncbi request reprint Uising WinBUGS to fit nonlinear mixed models with an application to pharmacokinetic modelling of insulin response to glucose challenge in sheep exposed antenatally to glucocorticoids
    Lyle C Gurrin
    Women and Infants Research Foundation, King Edward Memorial Hospital, Subiaco, Western Australia, Australia
    J Biopharm Stat 13:117-39. 2003
    ..It is argued that the fitting of an appropriate statistical model to complex physiological data does not necessarily proclude a result that has a clear interpretation for clinical scientists...
  31. ncbi request reprint Effect of labor on glucocorticoid receptor (GR(Total), GRalpha, and GRbeta) proteins in ovine intrauterine tissues
    Shalini Gupta
    CIHR Institute of Human Development, Child and Youth Health, Department of Physiology, University of Toronto, Toronto, Canada
    J Soc Gynecol Investig 10:136-44. 2003
    ..In the present study, we determined the temporal and tissue-specific expression of GR(Total), GRalpha, and GRbeta isoforms in ovine placenta, fetal membranes, and uterus during the onset and progression of labor...
  32. ncbi request reprint A periconceptional nutritional origin for noninfectious preterm birth
    Frank H Bloomfield
    Department of Physiology, University of Toronto, Toronto, Canada
    Science 300:606. 2003
  33. ncbi request reprint Expression of membrane prostaglandin E synthase in human placenta and fetal membranes and effect of labor
    Nadia Alfaidy
    Canadian Institutes of Health Research in Human Development, Child and Youth Health, Department of Physiology, University of Toronto, Toronto, Canada
    Endocrine 20:219-25. 2003
    ..The differences in expression found among placenta, chorion, and amnion before and after labor would indicate that this enzyme is differentially regulated in these tissues at this time...
  34. ncbi request reprint Mechanism of cortisol/progesterone antagonism in the regulation of 15-hydroxyprostaglandin dehydrogenase activity and messenger ribonucleic acid levels in human chorion and placental trophoblast cells at term
    Falguni A Patel
    Canadian Institutes for Health Research Group in Fetal and Neonatal Health and Development, Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    J Clin Endocrinol Metab 88:2922-33. 2003
    ..Our findings suggest that F inhibition and P(4) stimulation of PGDH may be mediated by PR, but also via the GR, in chorion and placenta...
  35. ncbi request reprint Brief undernutrition in late-gestation sheep programs the hypothalamic-pituitary-adrenal axis in adult offspring
    Frank H Bloomfield
    Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    Endocrinology 144:2933-40. 2003
    ..In contrast to our previous findings, these HPA effects are independent of birth weight and current weight, suggesting that different mechanisms may be involved in programming different physiological axes...
  36. ncbi request reprint Periconceptional undernutrition in sheep accelerates maturation of the fetal hypothalamic-pituitary-adrenal axis in late gestation
    Frank H Bloomfield
    Liggins Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
    Endocrinology 145:4278-85. 2004
    ....
  37. ncbi request reprint Expression of extracellular matrix metalloproteinase inducer in human placenta and fetal membranes at term labor
    Wei Li
    Canadian Institutes of Health Research Group in Fetal and Neonatal Health and Development, Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    J Clin Endocrinol Metab 89:2897-904. 2004
    ....
  38. ncbi request reprint Effect of the interaction between lipoxygenase pathway and progesterone on the regulation of hydroxysteroid 11-Beta dehydrogenase 2 in cultured human term placental trophoblasts
    Kazuyo Sato
    CIHR Group in Development and Fetal Health, Department of Physiology and Obstetrics and Gynecology and Medicine, University of Toronto, Ontario, Canada
    Biol Reprod 78:514-20. 2008
    ....
  39. ncbi request reprint Mifepristone: effect on plasma corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol in term pregnancy
    James D Byrne
    Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
    J Perinatol 24:416-20. 2004
    ..To compare the effects of in vivo mifepristone with placebo on plasma corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and cortisol levels concentrations in term human pregnancies...
  40. ncbi request reprint Molecular cloning and characterization of the von Hippel-Lindau-like protein
    Heng Qi
    Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King s College Circle, Toronto, Ontario M5S 1A8, Canada
    Mol Cancer Res 2:43-52. 2004
    ..These results taken together indicate that VLP functions as a dominant-negative VHL to serve as a protector of HIFalpha...
  41. ncbi request reprint Effects of dexamethasone and sulfasalazine on prostaglandin E2 output by human placental cells in vitro
    Nasser Mirazi
    Canadian Institutes for Health Research, Group in Fetal and Neonatal Health and Development, University of Toronto, Toronto, Ontario, Canada
    J Soc Gynecol Investig 11:22-6. 2004
    ....
  42. ncbi request reprint Differential expression and regulation of microsomal prostaglandin E(2) synthase in human fetal membranes and placenta with infection and in cultured trophoblast cells
    Marina Premyslova
    Canadian Institute of Health Research, Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
    J Clin Endocrinol Metab 88:6040-7. 2003
    ..However, multiple mechanisms, which apparently are inductor- and cell-type-specific, exist for the regulation of these enzymes...
  43. ncbi request reprint Transcriptional regulation of human myometrium and the onset of labor
    John R G Challis
    J Soc Gynecol Investig 12:65-6. 2005
  44. ncbi request reprint Nutrition and the early origins of adult disease
    John P Newnham
    School of Women s and Infants Health, University of Western Australia, King Edward Memorial Hospital for Women, Subiaco, Perth, Western Australia
    Asia Pac J Clin Nutr 11:S537-42. 2002
    ....