132 results on '"Cameron IT"'
Search Results
2. Representation and Analysis of Nonlinear Process Models with Quasipolynomial Graphs
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Australasian Chemical Engineering Conference (31st : 2003 : Adelaide, S.A.), Ingram, GD, Hangos, KM, and Cameron, IT
- Published
- 2003
3. Modelling of Flotation Circuits for Design and Control
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Chemeca 96 (24th : 1996 : Sydney, N.S.W.), Schroder, AJ, and Cameron, IT
- Published
- 1996
4. Dynamic System Characterisation for Design Purposes
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Chemeca 96 (24th : 1996 : Sydney, N.S.W.), Walsh, AM, and Cameron, IT
- Published
- 1996
5. Issues for Future Dynamic Process Simulators
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Conference on Control Engineering (1995 : Melbourne, Vic.), Newell, RB, and Cameron, IT
- Published
- 1995
6. Optimal Process Models in Process Dynamics
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Conference on Control Engineering (5th : 1992 : Perth, W.A.), Cameron, IT, Robertson, GA, Lee, PL, Signal, PD, and Newell, RB
- Published
- 1992
7. The Optimal Control of Copper Anode Furnaces
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Chemeca 92 (20th : 1992 : Canberra, A.C.T.), Bateman, IR, Cameron, IT, and Paladino, M
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- 1992
8. Dynamic Modelling Characteristics for Startup Simulation of a Forced Circulation Evaporator
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Chemeca 90 (18th : 1990 : Auckland, N. Z.), Robertson, GA, and Cameron, IT
- Published
- 1990
9. Optimal Control Strategies for an Industrial Evaporation Process: A Control Parameterization Approach
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Conference on Control Engineering (4th : 1990 : Gold Coast, Qld.), Cameron, IT, and Wang, FY
- Published
- 1990
10. Effect of asoprisnil on uterine proliferation markers and endometrial expression of the tumour suppressor gene, PTEN
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Wilkens, J, Williams, ARW, Chwalisz, K, Han, C, Cameron, IT, and Critchley, HOD
- Published
- 2009
11. Preliminary Hazop Studies Using Expert Systems
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Australasian Chemical Engineering Conference (1988 : Sydney, N.S.W.), Weatherill, T, and Cameron, IT
- Published
- 1988
12. Dynamic Simulation of Chemical Processes - a Structured Approach
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Australasian Chemical Engineering Conference (1988 : Sydney, N.S.W.), Gani, R, Toneva, G, and Cameron, IT
- Published
- 1988
13. Modelling and dynamics of distributed stage fractionators
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CHEMECA 89 (17th : 1989 : Gold Coast, Qld.), Hudson, CB, and Cameron, IT
- Published
- 1989
14. The influence of external forces, institutional forces, and academics' characteristics on the adoption of positive teaching practices across australian undergraduate engineering
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Knight, DB, Cameron, IT, Hadgraft, RG, and Reidsema, C
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ComputingMilieux_COMPUTERSANDEDUCATION ,Education - Abstract
© 2016 TEMPUS Publications. This study investigates how academics' personal beliefs, perspectives on institutional forces, and perspectives on external influences relate to their teaching and learning decision-making. Using a national-level survey of Australian engineering academics (n = 591; 16% of Australia's engineering academics), analyses investigate (1) how influences external and internal to the university environment vary across characteristics of academics, and (2) how academics' characteristics, organizational features, and external drivers relate to issues informing academics' teaching and their actual teaching practices. External and internal influences differed across academics based on their individual characteristics and university contexts, and academics' individual characteristics explained the greatest variability in their teaching considerations and practices. For external influences (e.g., accreditation), promoting awareness of educational goals for undergraduate engineering-as opposed to forcing outcomes into course planning-relates to more desirable teaching and learning practices. No internal institutional policy driver related to teaching practice variables. This study points to informed, professional development that seeks to capitalize on academics' personal interests and characteristics and assists in helping them understand how curricula and outcomes may better align to help student learning. Findings support working from a bottom-up model of change to improve the teaching and learning culture within engineering programs.
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- 2016
15. P18 Human endometrial stroma following exposure to the levonorgestrel intrauterine system (LNG-IUS)
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Treacy, J, McGavigan, CJ, Cameron, IT, Campbell, S, Warren, MA, Li, TC, and Dockery, P
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Proceedings of the Anatomical Society of Great Britain and Ireland - Published
- 2002
16. Beta cell differentiation during early human pancreas development
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Piper, K, primary, Brickwood, S, additional, Turnpenny, LW, additional, Cameron, IT, additional, Ball, SG, additional, Wilson, DI, additional, and Hanley, NA, additional
- Published
- 2004
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17. The role of nitric oxide in the maintenance of human pregnancy
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Norman, JE, primary, Thomson, AJ, additional, Telfer, JF, additional, Cameron, IT, additional, and Greer, IA, additional
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- 1998
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18. Endothelins in reproduction
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Cameron, IT, primary and Davenport, AP, additional
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- 1992
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19. Oocyte donation: A review
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Cameron, IT, primary, Rogers, PAW, additional, Caro, C, additional, Harman, J, additional, Healy, DL, additional, and Leeton, JF, additional
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- 1990
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20. A randomised comparison and economic evaluation of laparoscopic-assisted hysterectomy and abdominal hysterectomy.
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Lumsden MA, Twaddle S, Hawthorn R, Traynor I, Gilmore D, Davis J, Deeny M, Cameron IT, Walker JJ, Lumsden, M A, Twaddle, S, Hawthorn, R, Traynor, I, Gilmore, D, Davis, J, Deeny, M, Cameron, I T, and Walker, J J
- Published
- 2000
21. Nitric oxide in the endometrium.
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Cameron, IT, Campbell, S, and Cameron, I T
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ENDOMETRIUM physiology ,ANIMALS ,BLOOD platelet aggregation ,DYSMENORRHEA ,MENSTRUATION ,MYOMETRIUM ,NITRIC oxide ,OXIDOREDUCTASES ,UTERINE contraction ,VASOCONSTRICTION - Abstract
Nitric oxide (NO) is an important mediator of paracrine interactions, especially within the vascular system. It is a powerful inhibitor of platelet aggregation and a potent vasodilator. NO is also a neurotransmitter and it plays a role in cell-mediated cytotoxicity. NO-generating enzymes (nitric oxide synthases, NOS) have been described in the endometrium of a number of species, suggesting that NO might be involved in endometrial function. In human endometrium, endothelial NOS and inducible NOS have been localized to glandular epithelium in the non-pregnant uterus. Weak inducible NOS immunoreactivity has been observed in decidualized stromal cells. NO might participate in the initiation and control of menstrual bleeding. Furthermore, it may play a part in the inhibition of platelet aggregation within the endometrium, where menstrual haemostasis is thought to occur primarily by vasoconstriction rather than clot organization. Endometrially derived NO could also suppress myometrial contractility. Recent attention has focused on the part that NO might play in maintaining myometrial quiescence during pregnancy. NO also appears to relax the non-pregnant myometrium, an action which could be exploited for the medical treatment of primary dysmenorrhoea. [ABSTRACT FROM AUTHOR]
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- 1998
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22. Leukocytes infiltrate the myometrium during human parturition: further evidence that labour is an inflammatory process.
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Thomson, AJ, Telfer, JF, Young, A, Campbell, S, Stewart, CJR, Cameron, IT, Greer, IA, and Norman, JE
- Abstract
Inflammatory mediators in the cervix, placenta and fetal membranes play a crucial role in human parturition. The aim of this study was to determine whether the upper and lower segments of the myometrium are infiltrated by inflammatory cells during pregnancy and parturition. Myometrial biopsies were obtained from non-pregnant women, and pregnant women at term before and after the onset of spontaneous labour. Subpopulations of inflammatory cells were identified using immunocytochemistry. The intercellular adhesion molecules, 1 and 2, platelet endothelial cell adhesion molecule, vascular cell adhesion molecule and E-selectin were immunolocalized to investigate their involvement in leukocyte accumulation. Histological analysis demonstrated that inflammatory cells, predominantly neutrophils and macrophages, infiltrate human myometrium during spontaneous labour at term. The infiltrate is predominant in the lower uterine segment but is also present in the upper segment. Increased expression of E-selectin was found on the vascular endothelium of biopsies obtained during labour, suggesting a role for this molecule in the accumulation of leukocytes. These results suggest that inflammatory cell infiltration is part of the physiological mechanisms that occur in the myometrium during parturition. Further understanding of this process may suggest new strategies aimed at preventing preterm delivery. [ABSTRACT FROM PUBLISHER]
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- 1999
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23. Should sperm donors be paid? A survey of the attitudes of the general public.
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Lyall, H, Gould, GW, Cameron, IT, Gould, G W, and Cameron, I T
- Abstract
Gamete donation in assisted reproduction is an accepted treatment option for certain infertile couples. Traditionally, men donating spermatozoa have been paid a nominal fee, whilst women donating oocytes have not. The issue of payment for sperm donors has recently attracted attention following the Human Fertilisation and Embryology Authority's (HFEA) suggestion that such payment may be withdrawn. Prior to the final meeting of the HFEA working party which is examining this issue, here we report the results of a survey designed to solicit opinion on whether sperm donors should be paid, to identify social or other factors which influence this opinion, and to examine the influence of financial incentive on potential donors. We surveyed 717 individuals in three distinct groups: the general public, students (potential donors), and infertility patients (potential recipients). The majority of the potential donor group (students) was in favour of paying sperm donors, as were infertility patients. In contrast the general public was not. The opinion of the general public on this issue was influenced by their prior knowledge of whether donors were paid: those of the general public favouring the payment of sperm donors had a prior awareness that such payments were made. Although not in favour of paying sperm donors, the general public overwhelmingly approved of the use of donated spermatozoa for the treatment of infertile couples, and thought that ways should be sought to increase the availability of donor spermatozoa for the treatment of infertility and for research purposes. Within the potential donor group (students), the majority indicated that financial reward was an important factor which would influence their decision to donate spermatozoa. As the majority of both the potential recipients and potential donors feels that sperm donors should be paid, perhaps the views of these groups should carry significant weight when the decision whether or not to withdraw payment is taken. This is especially the case in view of the fact that the majority of the general public is in favour of the use of donated spermatozoa for the treatment of infertile couples. [ABSTRACT FROM PUBLISHER]
- Published
- 1998
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24. Endothelin receptor expression in human decidua.
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Kohnen, G, Campbell, S, Irvine, GA, Church, HJ, MacLachlan, F, Titterington, M, and Cameron, IT
- Abstract
Examines the expression of endothelin receptors, ET[sub A] and ET[sub B], in human decidua during pregnancy. Significant positive correlation between expression of ET[sub B] and laminin alpha[sub 2] light chain; Reduction of ET[sub A] in the stroma in the third trimester of pregnancy; Up-regulation of ET[sub B] during the progesterone-dependent process of decidualization.
- Published
- 1998
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25. Randomised trial of nitric oxide donor versus prostaglandin for cervical ripening before first-trimester termination of pregnancy.
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Thomson AJ, Lunan CB, Ledingham M, Howat RCL, Cameron IT, Greer IA, Norman JE, Thomson, A J, Lunan, C B, Ledingham, M, Howat, R C, Cameron, I T, Greer, I A, and Norman, J E
- Abstract
Background: Vaginal administration of the nitric oxide donor isosorbide mononitrate can induce effective ripening of the human cervix. We investigated whether this drug is associated with fewer side-effects than prostaglandins when used to ripen the cervix before first-trimester surgical termination of pregnancy, and assessed whether the extent of cervical ripening it induces is clinically sufficient.Methods: 66 primigravid women scheduled for surgical termination were assigned to receive before surgery, per vaginam, isosorbide mononitrate 40 mg or 80 mg, or the prostaglandin analogue gemeprost 1 mg. The primary measured outcome was onset of new symptoms before termination of pregnancy.Findings: More women remained symptom-free after isosorbide mononitrate than after gemeprost (28/44 [64%] vs 3/22 [14%], p<0.005). Pretreatment with gemeprost resulted in abdominal pain in 73% of women and vaginal bleeding in 32% compared with 3% and 0%, respectively, after isosorbide mononitrate, whereas, more women developed headache after isosorbide mononitrate (27%) than after gemeprost (0%). Cervical resistance and measured intraoperative blood loss were lowest after pretreatment with gemeprost. The measured cervical resistance and intraoperative blood loss with either dose of isosorbide mononitrate did not differ from those in a comparison group of 22 parous women not in the randomised trial.Interpretation: Pretreatment with isosorbide mononitrate to ripen the cervix before first-trimester termination of pregnancy is associated with fewer side-effects than gemeprost treatment and adequately decreases cervical resistance. Isosorbide mononitrate could be used as an alternative to gemeprost for this indication. [ABSTRACT FROM AUTHOR]- Published
- 1998
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26. Access to and sustainability of abortion services: a systematic review and meta-analysis for the National Institute of Health and Care Excellence-new clinical guidelines for England.
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O'Shea LE, Hawkins JE, Lord J, Schmidt-Hansen M, Hasler E, Cameron S, and Cameron IT
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- Adolescent, Adult, England epidemiology, Female, Guideline Adherence organization & administration, Guideline Adherence standards, Guideline Adherence statistics & numerical data, Humans, National Health Programs organization & administration, National Health Programs standards, National Health Programs statistics & numerical data, Pregnancy, Qualitative Research, Young Adult, Abortion, Induced standards, Abortion, Induced statistics & numerical data, Health Services Accessibility organization & administration, Health Services Accessibility standards, Health Services Accessibility statistics & numerical data, Practice Guidelines as Topic
- Abstract
Background: Induced abortion is a common procedure. However, there is marked variation in accessibility of services across England. Accessing abortion services may be difficult, particularly for women who live in remote areas, are in the second trimester of pregnancy, have complex pre-existing conditions or have difficult social circumstances., Objective and Rationale: This article presents a two-part review undertaken for a new National Institute of Health and Care Excellence guideline on abortion care, and aiming to determine: the factors that help or hinder accessibility and sustainability of abortion services in England (qualitative review), and strategies that improve these factors, and/or other factors identified by stakeholders (quantitative review). Economic modelling was undertaken to estimate cost savings associated with reducing waiting times., Search Methods: Ovid Embase Classic and Embase, Ovid MEDLINE(R) Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R), PsycINFO, Cochrane Library via Wiley Online, Cinahl Plus and Web of Science Core Collection were searched for articles published up to November 2018. Studies were included if they were published in English after 2001, conducted in Organization for Economic Co-operation and Development (OECD) countries and were: qualitative studies reporting views of patients and/or staff on factors that help or hinder the accessibility and sustainability of a safe abortion service, or randomized or non-randomized studies that compared strategies to improve factors identified by the qualitative review and/or stakeholders. Studies were excluded if they were conducted in OECD countries where abortion is prohibited altogether or only performed to save the woman's life. One author assessed risk of bias of included studies using the following checklists: Critical Appraisal Skills Programme checklist for qualitative studies, Cochrane Collaboration quality checklist for randomized controlled trials, Newcastle-Ottawa scale for cohort studies, and Effective Practice and Organization of Care risk of bias tool for before-and-after studies.Qualitative evidence was combined using thematic analysis and overall quality of the evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluations (GRADE) Confidence in the Evidence from Reviews of Qualitative Research (CERQual). Quantitative evidence was analysed in Review Manager 5.3 and overall quality of evidence was assessed using GRADE., Outcomes: Eight themes (service level barriers; financial barriers; logistical barriers; personal barriers; legal and policy barriers; privacy and confidentiality concerns; training and education; community prescribing and telemedicine introduce greater flexibility) and 18 subthemes were identified from 23 papers (n = 1016) included in the qualitative review. The quality of evidence ranged from very low to high, with evidence for one theme and seven subthemes rated as high quality. Nine studies (n = 7061) were included in the quantitative review which showed that satisfaction was better (low to high quality evidence) and women were seen sooner (very low quality evidence) when care was led by nurses or midwives compared with physician-led services, women were seen sooner when they could self-refer (very low quality evidence), and clinicians were more likely to provide abortions if training used an opt-out model (very low quality evidence). Economic modelling showed that even small reductions in waiting times could result in large cost savings for services., Wider Implications: Self-referral, funding for travel and accommodation, reducing waiting times, remote assessment, community services, maximizing the role of nurses and midwives and including practical experience of performing abortion in core curriculums, unless the trainee opts out, should improve access to and sustainability of abortion services., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2020
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27. Abnormal uterine bleeding.
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Cheong Y, Cameron IT, and Critchley HOD
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- 2019
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28. Cyclical progestogens for heavy menstrual bleeding.
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Bofill Rodriguez M, Lethaby A, Low C, and Cameron IT
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- Danazol therapeutic use, Female, Humans, Medroxyprogesterone Acetate therapeutic use, Progesterone administration & dosage, Progestins therapeutic use, Quality of Life, Randomized Controlled Trials as Topic, Tranexamic Acid therapeutic use, Intrauterine Devices, Medicated, Menorrhagia drug therapy, Progesterone therapeutic use
- Abstract
Background: Heavy menstrual bleeding (HMB) is a menstrual blood loss perceived by women as excessive that affects the health of women of reproductive age, interfering with their physical, emotional, social and material quality of life. Whilst abnormal menstrual bleeding may be associated with underlying pathology, in the present context, HMB is defined as excessive menstrual bleeding in the absence of other systemic or gynaecological disease. The first-line therapy is usually medical, avoiding possibly unnecessary surgery. Of the wide variety of medications used to reduce HMB, oral progestogens were originally the most commonly prescribed agents. This review assesses the effectiveness of two different types and regimens of oral progestogens in reducing ovulatory HMB.This is the update of a Cochrane review last updated in 2007, and originally named "Effectiveness of cyclical progestagen therapy in reducing heavy menstrual bleeding" (1998)., Objectives: To determine the effectiveness, safety and tolerability of oral progestogen therapy taken either during the luteal phase (short cycle) or for a longer course of 21 days per cycle (long cycle), in achieving a reduction in menstrual blood loss in women of reproductive age with HMB., Search Methods: In January 2019 we searched Cochrane Gynaecology and Fertility's specialized register, CENTRAL, MEDLINE, Embase, CINAHL and PsycInfo. We also searched trials registers, other sources of unpublished or grey literature and reference lists of retrieved trials. We also checked citation lists of review articles to identify trials., Selection Criteria: Randomized controlled trials (RCTs) comparing different treatments for HMB that included cyclical oral progestogens were eligible., Data Collection and Analysis: Two review authors independently selected trials for inclusion, assessed trials for risk of bias and extracted data. We contacted trial authors for clarification of methods or additional data when necessary. We only assessed adverse events if they were separately measured in the included trials. We compared cyclical oral progestogen in different regimens and placebo or other treatments. Our primary outcomes were menstrual blood loss and satisfaction with treatment; the secondary outcomes were number of days of bleeding, quality of life, compliance and acceptability of treatment, adverse events and costs., Main Results: This review identified 15 randomized controlled trials (RCTs) with 1071 women in total. Most of the women knew which treatment they were receiving, which may have influenced their judgements about menstrual blood loss and satisfaction. Other aspects of trial quality varied among trials.We did not identify any RCTs comparing progestogen treatment with placebo. We assessed comparisons between oral progestogens and other medical therapies separately according to different regimens.Short-cycle progestogen therapy during the luteal phase (medroxyprogesterone acetate or norethisterone for 7 to 10 days, from day 15 to 19) was inferior to other medical therapy, including tranexamic acid, danazol and the progestogen-releasing intrauterine system (Pg-IUS (off of the market since 2001)), releasing 60 mcg of progesterone daily, with respect to reduction of menstrual blood loss (mean difference (MD) 37.29, 95% confidence interval (CI) 17.67 to 56.91; I
2 = 50%; 6 trials, 145 women). The rate of satisfaction and the quality of life with treatment was similar in both groups. The number of bleeding days was greater on the short cycle progestogen group compared to other medical treatments. Adverse events (such as gastrointestinal symptoms and weight gain) were more likely with danazol when compared with progestogen treatment. We note that danazol is no longer in general use for treating HMB.Long-cycle progestogen therapy (medroxyprogesterone acetate or norethisterone), from day 5 to day 26 of the menstrual cycle, is also inferior to the levonorgestrel-releasing intrauterine system (LNG-IUS), releasing tranexamic acid and ormeloxifene, but may be similar to the combined vaginal ring with respect to reduction of menstrual blood loss (MD 16.88, 95% CI 10.93 to 22.84; I2 = 87%; 4 trials, 355 women). A higher proportion of women taking norethisterone found their treatment unacceptable compared to women having Pg-IUS (Peto odds ratio (OR) 0.12, 95% CI 0.03 to 0.40; 1 trial, 40 women). However, the adverse effects of breast tenderness and intermenstrual bleeding were more likely in women with the LNG-IUS. No trials reported on days of bleeding or quality of life for this comparison.The evidence supporting these findings was limited by low or very low gradings of quality; thus, we are uncertain about the findings and there is a potential that they may change if we identify other trials., Authors' Conclusions: Low- or very low-quality evidence suggests that short-course progestogen was inferior to other medical therapy, including tranexamic acid, danazol and the Pg-IUS with respect to reduction of menstrual blood loss. Long cycle progestogen therapy (medroxyprogesterone acetate or norethisterone) was also inferior to the LNG-IUS, tranexamic acid and ormeloxifene, but may be similar to the combined vaginal ring with respect to reduction of menstrual blood loss.- Published
- 2019
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29. Abnormal uterine bleeding.
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Cheong Y, Cameron IT, and Critchley HOD
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- Adenomyosis complications, Adenomyosis diagnosis, Female, Humans, Hysterectomy, Leiomyoma complications, Leiomyoma diagnosis, Polyps complications, Polyps diagnosis, Quality of Life, Uterine Hemorrhage therapy, Uterine Hemorrhage etiology
- Abstract
Introduction: It is not uncommon for a woman to suffer from abnormal uterine bleeding (AUB) or heavy menstrual bleeding (HMB) at some point during her lifetime. Once pathology is excluded, in practice, management needs to be individualised, taking into account the improvement of the woman's symptoms and quality of life., Sources of Data: Peer-reviewed journals, governmental and professional society publications., Areas of Agreement: There is now agreement on a structured, universal approach to the diagnosis of AUB, with the aide memoirs PALM (polyps, adenomyosis, leiomyoma, malignancy) and COEIN (coagulopathies, ovulatory dysfunction, endometrial, iatrogenic, not otherwise classified). Once malignancy and significant pelvic pathology have been ruled out, medical treatment is an effective first-line therapeutic option, with surgery, including endometrial ablation and hysterectomy, offered when medical management has failed to resolve symptoms and fertility is no longer desired., Areas of Controversy: There remains controversy around the management of the types and subtypes of adenomyosis and leiomyoma, and understanding their impact on clinical reproductive outcomes., Areas Currently Under Development: Standardised assessment tools for measuring outcomes of AUB are being developed., Areas Timely for Developing Research: Novel diagnostic and monitoring tools should be developed to help stratify treatment for women with AUB, particularly relating to 'unclassified' and 'endometrial' causes., (© The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)
- Published
- 2017
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30. The 'Developmental Origins' Hypothesis: relevance to the obstetrician and gynecologist.
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Kermack AJ, Van Rijn BB, Houghton FD, Calder PC, Cameron IT, and Macklon NS
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- Adult, Female, Humans, Maternal Nutritional Physiological Phenomena, Pregnancy, Prenatal Exposure Delayed Effects, Cardiovascular System physiopathology, Embryonic Development, Fetal Development, Gynecology, Obstetrics
- Abstract
The recognition of 'fetal origins of adult disease' has placed new responsibilities on the obstetrician, as antenatal care is no longer simply about ensuring good perinatal outcomes, but also needs to plan for optimal long-term health for mother and baby. Recently, it has become clear that the intrauterine environment has a broad and long-lasting impact, influencing fetal and childhood growth and development as well as future cardiovascular health, non-communicable disease risk and fertility. This article looks specifically at the importance of the developmental origins of ovarian reserve and ageing, the role of the placenta and maternal nutrition before and during pregnancy. It also reviews recent insights in developmental medicine of relevance to the obstetrician, and outlines emerging evidence supporting a proactive clinical approach to optimizing periconceptional as well as antenatal care aimed to protect newborns against long-term disease susceptibility.
- Published
- 2015
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31. Prescribing safety: ensuring that new graduates are prepared.
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Maxwell SRJ, Cameron IT, and Webb DJ
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- Humans, Clinical Competence standards, Curriculum, Education, Medical, Undergraduate methods, Prescriptions standards
- Published
- 2015
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32. Uterine NK cells regulate endometrial bleeding in women and are suppressed by the progesterone receptor modulator asoprisnil.
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Wilkens J, Male V, Ghazal P, Forster T, Gibson DA, Williams AR, Brito-Mutunayagam SL, Craigon M, Lourenco P, Cameron IT, Chwalisz K, Moffett A, and Critchley HO
- Subjects
- Double-Blind Method, Endometrium drug effects, Endometrium immunology, Endometrium metabolism, Female, Humans, Immunohistochemistry, Interleukin-15, Killer Cells, Natural immunology, Leiomyoma complications, Leiomyoma immunology, Lymphocyte Activation drug effects, Oligonucleotide Array Sequence Analysis, Receptors, Progesterone biosynthesis, Reverse Transcriptase Polymerase Chain Reaction, Transcriptome, Uterine Neoplasms complications, Uterine Neoplasms immunology, Uterus, Estrenes therapeutic use, Killer Cells, Natural metabolism, Leiomyoma drug therapy, Oximes therapeutic use, Uterine Neoplasms drug therapy
- Abstract
Uterine NK cells (uNK) play a role in the regulation of placentation, but their functions in nonpregnant endometrium are not understood. We have previously reported suppression of endometrial bleeding and alteration of spiral artery morphology in women exposed to asoprisnil, a progesterone receptor modulator. We now compare global endometrial gene expression in asoprisnil-treated versus control women, and we demonstrate a statistically significant reduction of genes in the IL-15 pathway, known to play a key role in uNK development and function. Suppression of IL-15 by asoprisnil was also observed at mRNA level (p < 0.05), and immunostaining for NK cell marker CD56 revealed a striking reduction of uNK in asoprisnil-treated endometrium (p < 0.001). IL-15 levels in normal endometrium are progesterone-responsive. Progesterone receptor (PR) positive stromal cells transcribe both IL-15 and IL-15RA. Thus, the response of stromal cells to progesterone will be to increase IL-15 trans-presentation to uNK, supporting their expansion and differentiation. In asoprisnil-treated endometrium, there is a marked downregulation of stromal PR expression and virtual absence of uNK. These novel findings indicate that the IL-15 pathway provides a missing link in the complex interplay among endometrial stromal cells, uNK, and spiral arteries affecting physiologic and pathologic endometrial bleeding.
- Published
- 2013
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33. Metabolic induction and early responses of mouse blastocyst developmental programming following maternal low protein diet affecting life-long health.
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Eckert JJ, Porter R, Watkins AJ, Burt E, Brooks S, Leese HJ, Humpherson PG, Cameron IT, and Fleming TP
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- Amino Acids blood, Animals, Blood Glucose, Corticosterone blood, Estrogens blood, Female, Health, Insulin blood, Male, Maternal Nutritional Physiological Phenomena, Mechanistic Target of Rapamycin Complex 1, Mice, Multiprotein Complexes, Phenotype, Phosphorylation, Pregnancy, Protein Processing, Post-Translational, Proteins metabolism, Signal Transduction, TOR Serine-Threonine Kinases, Uterus metabolism, Blastocyst metabolism, Diet, Protein-Restricted adverse effects, Embryonic Development, Prenatal Exposure Delayed Effects metabolism
- Abstract
Previously, we have shown that a maternal low protein diet, fed exclusively during the preimplantation period of mouse development (Emb-LPD), is sufficient to induce by the blastocyst stage a compensatory growth phenotype in late gestation and postnatally, correlating with increased risk of adult onset cardiovascular disease and behavioural dysfunction. Here, we examine mechanisms of induction of maternal Emb-LPD programming and early compensatory responses by the embryo. Emb-LPD induced changes in maternal serum metabolites at the time of blastocyst formation (E3.5), notably reduced insulin and increased glucose, together with reduced levels of free amino acids (AAs) including branched chain AAs leucine, isoleucine and valine. Emb-LPD also caused reduction in the branched chain AAs within uterine fluid at the blastocyst stage. These maternal changes coincided with an altered content of blastocyst AAs and reduced mTORC1 signalling within blastocysts evident in reduced phosphorylation of effector S6 ribosomal protein and its ratio to total S6 protein but no change in effector 4E-BP1 phosphorylated and total pools. These changes were accompanied by increased proliferation of blastocyst trophectoderm and total cells and subsequent increased spreading of trophoblast cells in blastocyst outgrowths. We propose that induction of metabolic programming following Emb-LPD is achieved through mTORC1signalling which acts as a sensor for preimplantation embryos to detect maternal nutrient levels via branched chain AAs and/or insulin availability. Moreover, this induction step associates with changes in extra-embryonic trophectoderm behaviour occurring as early compensatory responses leading to later nutrient recovery.
- Published
- 2012
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34. Maternal muscle mass may influence system A activity in human placenta.
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Lewis RM, Greenwood SL, Cleal JK, Crozier SR, Verrall L, Inskip HM, Cameron IT, Cooper C, Sibley CP, Hanson MA, and Godfrey KM
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- Adaptation, Physiological, Adult, Body Mass Index, Female, Humans, Infant, Newborn, Muscle, Skeletal physiology, Physical Fitness physiology, Pregnancy, Term Birth, Young Adult, Amino Acid Transport System A metabolism, Body Composition physiology, Muscle, Skeletal anatomy & histology, Placenta metabolism
- Abstract
During pregnancy, nutrient partitioning between the mother and fetus must balance promoting fetal survival and maintaining nutritional status of the mother for her health and future fertility. The nutritional status of the pregnant woman, reflected in her body composition, may affect placental function with consequences for fetal development. We investigated the relationship between maternal body composition and placental system A amino acid transporter activity in 103 term placentas from Southampton Women's Survey pregnancies. Placental system A activity was measured as Na(+)-dependent uptake of 10 mumol/L (14)C-methylaminoisobutyric acid (a system A specific amino acid analogue) in placental villous fragments. Maternal body composition was measured at enrollment pre-pregnancy; in 45 infants neonatal body composition was measured using dual-energy x-ray absorptiometry. Term placental system A activity was lower in women with smaller pre-pregnancy upper arm muscle area (r = 0.27, P = 0.007), but was not related to maternal fat mass. System A activity was lower in mothers who reported undertaking strenuous exercise (24.6 vs 29.7 pmol/mg/15 min in sedentary women, P = 0.03), but was not associated with other maternal lifestyle factors. Lower placental system A activity in women who reported strenuous exercise and had a lower arm muscle area may reflect an adaptation in placental function which protects maternal resources in those with lower nutrient reserves. This alteration may affect fetal development, altering fetal body composition, with long-term consequences., ((c) 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
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35. Stimulation of lactate production in human granulosa cells by metformin and potential involvement of adenosine 5' monophosphate-activated protein kinase.
- Author
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Richardson MC, Ingamells S, Simonis CD, Cameron IT, Sreekumar R, Vijendren A, Sellahewa L, Coakley S, and Byrne CD
- Subjects
- AMP-Activated Protein Kinases metabolism, Adiponectin pharmacology, Cells, Cultured, Dose-Response Relationship, Drug, Female, Granulosa Cells metabolism, Humans, Hypoglycemic Agents pharmacology, Insulin pharmacology, Models, Biological, Time Factors, Up-Regulation drug effects, AMP-Activated Protein Kinases physiology, Granulosa Cells drug effects, Lactic Acid metabolism, Metformin pharmacology
- Abstract
Context: Production of 3-carbon units (as lactate) by granulosa cells (GCs) is important in follicular and oocyte development and may be modulated by metformin., Objective: The aim of the study was to examine the action of metformin on GC lactate production and potential mediation via AMP-activated protein kinase (AMPK)., Design: GCs were prepared from follicular aspirates. After exposure to metformin and other potential modulators of AMPK in culture, aspects of cellular function were examined., Setting: The study was conducted in a private fertility clinic/university academic center., Patients: Women undergoing routine in vitro fertilization participated in the study., Interventions: All agents were added in culture., Main Outcome Measures: Lactate output of GCs was measured. Cell extracts were prepared after culture, and phosphorylated forms of AMPK and acetyl CoA carboxylase (ACC) were assayed using Western analysis., Results: Metformin led to a rapid increase in lactate production by GCs [minimum effective dose, 250 microm; maximum dose studied, 1 mm (1.22-fold; P < 0.01)]. This dose range of metformin was similar to that required for stimulation of phospho-AMPK in GCs [minimum effective dose, 250 microm; maximum effect, 500 microm (2.01-fold; P < 0.001)]. Increasing phospho-ACC, as a representative downstream target regulated by AMPK, was apparent over a lower range (minimum effective dose, 31 microm; maximum effect, 250 microm; P < 0.001). A level of metformin (125 microm) insufficient for the stimulation of lactate output when used alone potentiated the effects of suboptimal doses of insulin on lactate production. Adiponectin (2.5 microg/ml) had a small but significant effect on lactate output., Conclusions: Metformin activates AMPK in GCs, stimulating lactate production and increasing phospho-ACC. Metformin also enhances the action of suboptimal insulin concentrations to stimulate lactate production.
- Published
- 2009
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36. Effects of the selective progesterone receptor modulator asoprisnil on uterine artery blood flow, ovarian activity, and clinical symptoms in patients with uterine leiomyomata scheduled for hysterectomy.
- Author
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Wilkens J, Chwalisz K, Han C, Walker J, Cameron IT, Ingamells S, Lawrence AC, Lumsden MA, Hapangama D, Williams AR, and Critchley HO
- Subjects
- Adult, Arteries drug effects, Data Interpretation, Statistical, Double-Blind Method, Endometrium pathology, Female, Humans, Menstruation drug effects, Middle Aged, Myometrium pathology, Ovary drug effects, Pregnanediol blood, Quality of Life, Regional Blood Flow drug effects, Ultrasonography, Doppler, Color, Uterine Hemorrhage complications, Uterine Hemorrhage prevention & control, Vascular Resistance drug effects, Estrenes pharmacology, Hysterectomy, Leiomyoma drug therapy, Leiomyoma surgery, Ovary physiology, Oximes pharmacology, Receptors, Progesterone drug effects, Uterine Neoplasms drug therapy, Uterine Neoplasms surgery, Uterus blood supply
- Abstract
Introduction: Asoprisnil, a novel orally active selective progesterone receptor modulator, is being studied for the management of symptomatic uterine leiomyomata. The exact mechanism of action is not yet discerned. The primary objectives of this double-blind, randomized, placebo-controlled study included evaluation of the effect of asoprisnil on uterine artery blood flow. Furthermore, we assessed effects of asoprisnil on leiomyoma symptoms., Patients and Methods: Thirty-three premenopausal patients scheduled for hysterectomy due to symptomatic uterine leiomyomata were recruited in four centers and treated with 10 or 25 mg asoprisnil or placebo for 12 wk before surgery. At baseline and before hysterectomy, all patients underwent sonographic assessment to measure impedance to uterine artery blood flow, determined by resistance index and pulsatility index, as well as volumes of largest leiomyoma and uterus. In addition, patients recorded intensity and frequency of menstrual bleeding on a menstrual pictogram. Each asoprisnil treatment was compared with placebo., Results: The increased pulsatility index in both asoprisnil groups and the statistically significantly increased resistance index within the 25-mg asoprisnil group suggest a moderately decreased uterine artery blood flow. Analysis of menstrual pictogram scores showed a statistically significant larger decrease in frequency and intensity of bleeding for both asoprisnil groups compared with placebo. Bleeding was suppressed by asoprisnil 25mg in 91% of patients. Asoprisnil treatment was well tolerated when administered daily for a 12-wk period, and no serious adverse events occurred., Conclusion: Asoprisnil moderately reduced uterine artery blood flow. This effect may contribute in part to the clinical effects of asoprisnil.
- Published
- 2008
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37. The early human germ cell lineage does not express SOX2 during in vivo development or upon in vitro culture.
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Perrett RM, Turnpenny L, Eckert JJ, O'Shea M, Sonne SB, Cameron IT, Wilson DI, Rajpert-De Meyts E, and Hanley NA
- Subjects
- Animals, Cells, Cultured, DNA-Binding Proteins genetics, Embryonic Stem Cells cytology, Female, Germ Cells cytology, HMGB Proteins genetics, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Humans, Male, Mice, Nanog Homeobox Protein, Neoplasms, Germ Cell and Embryonal metabolism, Neoplasms, Germ Cell and Embryonal pathology, Octamer Transcription Factor-3 genetics, Octamer Transcription Factor-3 metabolism, Ovary cytology, Ovary embryology, Ovary metabolism, SOXB1 Transcription Factors, Testis cytology, Testis embryology, Testis metabolism, Transcription Factors genetics, Cell Lineage genetics, DNA-Binding Proteins metabolism, Embryonic Stem Cells metabolism, Gene Expression Regulation, Developmental physiology, Germ Cells metabolism, HMGB Proteins metabolism, Transcription Factors metabolism
- Abstract
NANOG, POU5F1, and SOX2 are required by the inner cell mass of the blastocyst and act cooperatively to maintain pluripotency in both mouse and human embryonic stem cells. Inadequacy of any one of them causes loss of the undifferentiated state. Mouse primordial germ cells (PGCs), from which pluripotent embryonic germ cells (EGCs) are derived, also express POU5F1, NANOG, and SOX2. Thus, a similar expression profile has been predicted for human PGCs. Here we show by RT-PCR, immunoblotting, and immunohistochemistry that human PGCs express POU5F1 and NANOG but not SOX2, with no evidence of redundancy within the group B family of human SOX genes. Although lacking SOX2, proliferative human germ cells can still be identified in situ during early development and are capable of culture in vitro. Surprisingly, with the exception of FGF4, many stem cell-restricted SOX2 target genes remained detected within the human SOX2-negative germ cell lineage. These studies demonstrate an unexpected difference in gene expression between human and mouse. The human PGC is the first primary cell type described to express POU5F1 and NANOG but not SOX2. The data also provide a new reference point for studies attempting to turn human stem cells into gametes by normal developmental pathways for the treatment of infertility.
- Published
- 2008
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38. Human embryos developing in vitro are susceptible to impaired epithelial junction biogenesis correlating with abnormal metabolic activity.
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Eckert JJ, Houghton FD, Hawkhead JA, Balen AH, Leese HJ, Picton HM, Cameron IT, and Fleming TP
- Subjects
- Amino Acids metabolism, Blastocyst pathology, Blastocyst ultrastructure, Epithelium, Humans, In Vitro Techniques, Morula pathology, Morula ultrastructure, Blastocyst physiology, Morula physiology, Tight Junctions physiology
- Abstract
Background: Blastocyst biogenesis occurs over several cell cycles during the preimplantation period comprising the gradual expression and membrane assembly of junctional protein complexes which distinguish the outer epithelial trophectoderm (TE) cells from the inner cell mass (ICM). In the human, TE integrity and the formation of a junctional seal can often be impaired. Embryos likely to result in a successful pregnancy after transfer are mostly selected according to morphological criteria. Recent data suggest that non-invasive measurement of amino acid turnover may be useful to complement such morphological scores. Whether morphological and metabolic criteria can be linked to poor TE differentiation thereby underpinning developmental predictions mechanistically remains unknown., Methods: We examined TE intercellular junction formation in human embryos by immunofluorescence and confocal microscopy and correlated this process with morphological criteria and amino acid turnover during late cleavage., Results: Our results show that TE differentiation may be compromised by failure of membrane assembly of specific junction constituents. This abnormality relates more closely to metabolic profiles than morphological criteria., Conclusion: Our data identify that amino acid turnover can predict TE differentiation. These findings are the first to link two mechanisms, metabolism and junction membrane assembly, which contribute to early embryo development.
- Published
- 2007
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39. The effects of the selective progesterone receptor modulator asoprisnil on the morphology of uterine tissues after 3 months treatment in patients with symptomatic uterine leiomyomata.
- Author
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Williams AR, Critchley HO, Osei J, Ingamells S, Cameron IT, Han C, and Chwalisz K
- Subjects
- Adult, Endometrium drug effects, Endometrium pathology, Estrenes administration & dosage, Female, Humans, Leiomyoma drug therapy, Middle Aged, Myometrium drug effects, Myometrium pathology, Oximes administration & dosage, Placebos, Uterine Neoplasms drug therapy, Estrenes adverse effects, Leiomyoma pathology, Oximes adverse effects, Receptors, Progesterone drug effects, Uterine Neoplasms pathology, Uterus drug effects, Uterus pathology
- Abstract
Background: Asoprisnil is a selective progesterone receptor modulator with mixed progesterone agonist/antagonist activity which controls uterine bleeding via an endometrial effect. This study examined full-thickness endometrial, leiomyoma and myometrial morphology in hysterectomy specimens from patients with uterine leiomyomata, after treatment with asoprisnil for 3 months., Methods: In this double-blind, randomized, placebo-controlled study, 33 subjects with uterine leiomyomata were randomized to receive asoprisnil 10, 25 mg or placebo for an average of 95 days prior to hysterectomy. Samples of endometrium, myometrium and leiomyoma tissue were subjected to systematic morphological assessment with quantification of mitotic activity., Results: In patients treated with 10 or 25 mg asoprisnil, a unique pattern called 'non-physiologic secretory effect' was evident in endometrium, recognizable through partially developed secretory glandular appearances and stromal changes. Endometrial thickness was decreased, and there were low levels of mitotic activity in endometrial glands and stroma. Unusual thick-walled muscular arterioles and prominent aggregations of thin-walled vessels were present in endometrial stroma, but not in myometrium or non-endometrial vascular beds. Mitotic activity was decreased in leiomyomata., Conclusions: Asoprisnil induces unique morphological changes and is associated with low levels of glandular and stromal proliferation in endometrium, and in leiomyomata. These changes are likely to contribute to the amenorrhoea experienced after exposure to the medication.
- Published
- 2007
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40. L-serine uptake by human placental microvillous membrane vesicles.
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Lewis RM, Glazier J, Greenwood SL, Bennett EJ, Godfrey KM, Jackson AA, Sibley CP, Cameron IT, and Hanson MA
- Subjects
- Amino Acid Transport System A genetics, Amino Acid Transport System y+ genetics, Amino Acid Transport System y+L genetics, Biological Transport genetics, Female, Fusion Regulatory Protein 1, Light Chains genetics, Humans, Neoplasm Proteins genetics, Pregnancy, Sodium-Calcium Exchanger genetics, Microvilli metabolism, Placenta metabolism, Serine metabolism
- Abstract
The human fetus requires more glycine than any other amino acid but placental glycine transfer to the fetus is insufficient to meet fetal demand. L-Serine could represent a major metabolic source of glycine for the human fetus but little is known about the kinetics and physiology of L-serine uptake by the human placenta. We have characterised the amino acid transport systems involved in the uptake of L-serine by the microvillous membrane of the human placental syncytiotrophoblast and compared the uptake rates to those of glycine. L-Serine uptake into microvillous membrane (MVM) vesicles was primarily mediated by system A (MeAIB inhibitable) and system L (BCH inhibitable). Further characterisation using specific substrates of LAT1 and LAT2 found the pattern of L-serine uptake was consistent with that expected for uptake mediated by LAT2. Uptakes were performed with tracer levels of (14)C-L-serine, physiological levels of L-serine, or with physiological levels of amino acids. As amino acid concentrations rose, the proportion of uptake by System L decreased while uptake by uncharacterised Na(+)-independent systems increased. Uptake of Lserine into MVM vesicles had a V(max) of 2.1+/-0.4 nmol/mg protein/min, which was significantly higher than for glycine (V(max) 1.0+/-0.2 nmol/mg protein/min). This indicates that MVM vesicles have a higher uptake capacity for L-serine than glycine, despite a greater demand for glycine over serine for fetal protein synthesis. Further studies are now required to define the fate of L-serine taken up by the placenta and its importance for the fetus.
- Published
- 2007
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41. Quantitated transcript haplotypes (QTH) of AGTR1, reduced abundance of mRNA haplotypes containing 1166C (rs5186:A>C), and relevance to metabolic syndrome traits.
- Author
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Abdollahi MR, Lewis RM, Gaunt TR, Cumming DV, Rodriguez S, Rose-Zerilli M, Collins AR, Syddall HE, Howell WM, Cooper C, Godfrey KM, Cameron IT, and Day IN
- Subjects
- Aged, Alleles, Female, Haplotypes, Humans, Male, Metabolic Syndrome metabolism, Middle Aged, Placenta metabolism, Placenta physiology, Polymorphism, Single Nucleotide, RNA, Messenger genetics, Receptor, Angiotensin, Type 1 biosynthesis, Metabolic Syndrome genetics, RNA, Messenger biosynthesis, Receptor, Angiotensin, Type 1 genetics
- Abstract
The angiotensin II type 1 receptor (AGTR1) is the main target through which angiotensin II influences cardiovascular tone, cell growth, and fluid and electrolyte balance. AGTR1 polymorphism has been reported to associate with hypertension, myocardial infarction (MI), and metabolic traits. Here we describe a novel approach to quantitation of transcript haplotypes (QTH) of AGTR1. To determine relative allelic expression from haplotypes, within-individual-between-allele ratiometric analyses in placental cDNA were developed for the transcribed SNPs rs5182:C>T (encoding p.L191) and rs5186:A>C (3'-noncoding "A1166C"). Additionally, between-individual comparisons were made using TaqMan assays applied to both homozygous and heterozygous genotypes and haplotypes. In conjunction, linkage disequilibrium (LD) and genomic haplotype associations with metabolic syndrome were examined. There was no significant difference of mRNA level for alleles of rs5182:C>T, but allele and mRNA haplotypes carrying 1166C exhibited reduced abundance. The effect was much greater in CC homozygotes than in heterozygotes. The promoter region was confirmed to be in a separate haplotype block from the AGTR1 3' region containing rs5182:C>T and rs5186:A>C. Metabolic syndrome trait associations were strongest for the 3' block generally and for the C allele of rs5186:A>C specifically. All effects were much more prominent in homozygotes, possibly reflecting interallelic interaction through feedback loops of mRNA regulation. Differential abundance of AGTR1 mRNA haplotypes may mediate clinical phenotypic observations of the AGTR1 genotype., (Copyright 2007 Wiley-Liss, Inc.)
- Published
- 2007
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42. In humans, early cortisol biosynthesis provides a mechanism to safeguard female sexual development.
- Author
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Goto M, Piper Hanley K, Marcos J, Wood PJ, Wright S, Postle AD, Cameron IT, Mason JI, Wilson DI, and Hanley NA
- Subjects
- 3-Hydroxysteroid Dehydrogenases genetics, 3-Hydroxysteroid Dehydrogenases metabolism, Adrenal Cortex embryology, Adrenal Cortex metabolism, Androgens biosynthesis, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, Gene Expression Regulation, Gestational Age, Humans, Hydrocortisone metabolism, Models, Biological, Nuclear Receptor Subfamily 4, Group A, Member 1, Pituitary Gland, Anterior embryology, Pituitary Gland, Anterior growth & development, Pituitary Gland, Anterior metabolism, Receptors, Cytoplasmic and Nuclear genetics, Receptors, Cytoplasmic and Nuclear metabolism, Receptors, Steroid genetics, Receptors, Steroid metabolism, Transcription Factors genetics, Transcription Factors metabolism, Hydrocortisone biosynthesis, Sex Differentiation, Sexual Development physiology
- Abstract
In humans, sexual differentiation of the external genitalia is established at 7-12 weeks post conception (wpc). During this period, maintaining the appropriate intrauterine hormone environment is critical. In contrast to other species, this regulation extends to the human fetal adrenal cortex, as evidenced by the virilization that is associated with various forms of congenital adrenal hyperplasia. The mechanism underlying these clinical findings has remained elusive. Here we show that the human fetal adrenal cortex synthesized cortisol much earlier than previously documented, an effect associated with transient expression of the orphan nuclear receptor nerve growth factor IB-like (NGFI-B) and its regulatory target, the steroidogenic enzyme type 2 3beta-hydroxysteroid dehydrogenase (HSD3B2). This cortisol biosynthesis was maximal at 8-9 wpc under the regulation of ACTH. Negative feedback was apparent at the anterior pituitary corticotrophs. ACTH also stimulated the adrenal gland to secrete androstenedione and testosterone. In concert, these data promote a distinctive mechanism for normal human development whereby cortisol production, determined by transient NGFI-B and HSD3B2 expression, provides feedback at the anterior pituitary to modulate androgen biosynthesis and safeguard normal female sexual differentiation.
- Published
- 2006
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43. Evaluating human embryonic germ cells: concord and conflict as pluripotent stem cells.
- Author
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Turnpenny L, Spalluto CM, Perrett RM, O'Shea M, Hanley KP, Cameron IT, Wilson DI, and Hanley NA
- Subjects
- Animals, Cell Culture Techniques methods, Cell Differentiation, Cell Movement, Cell Proliferation, Cell- and Tissue-Based Therapy methods, Culture Media chemistry, Embryo, Mammalian physiology, Gene Expression Profiling, Gene Expression Regulation, Developmental, Germ Cells chemistry, Growth Substances physiology, Humans, Mice, Embryo, Mammalian cytology, Germ Cells physiology, Pluripotent Stem Cells physiology
- Abstract
The realization of cell replacement therapy derived from human pluripotent stem cells requires full knowledge of the starting cell types as well as their differentiated progeny. Alongside embryonic stem cells, embryonic germ cells (EGCs) are an alternative source of pluripotent stem cell. Since 1998, four groups have described the derivation of human EGCs. This review analyzes the progress on derivation, culture, and differentiation, drawing comparison with other pluripotent stem cell populations.
- Published
- 2006
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44. Human embryonic germ cells for future neuronal replacement therapy.
- Author
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Turnpenny L, Cameron IT, Spalluto CM, Hanley KP, Wilson DI, and Hanley NA
- Subjects
- Animals, Gonads cytology, Gonads embryology, Humans, Brain Diseases therapy, Germ Cells cytology, Neurons cytology, Pluripotent Stem Cells cytology, Stem Cell Transplantation methods
- Abstract
Stem cell therapy offers exciting potential for ambitious cellular replacement to treat human (h) disease, such as Parkinson's disease, Alzheimer's disease or even replacement of the cell death that follows thromboembolic stroke. The realisation of these treatments requires cellular resources possessing three essential characteristics: (i) self-renewal, (ii) the ability to differentiate to physiologically normal cell types and (iii) lack of tumourigenicity. Here, we describe work on human embryonic germ cells (hEGCs), a population of cells alongside human embryonic stem cells (hESCs) with the potential to address these issues.
- Published
- 2005
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45. Relative contribution of cell contact pattern, specific PKC isoforms and gap junctional communication in tight junction assembly in the mouse early embryo.
- Author
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Eckert JJ, McCallum A, Mears A, Rumsby MG, Cameron IT, and Fleming TP
- Subjects
- Animals, Blastocyst enzymology, Cell Membrane enzymology, Ectoderm enzymology, Female, Isoenzymes physiology, Mice, Tight Junctions enzymology, Up-Regulation, Blastocyst physiology, Cell Communication physiology, Gap Junctions physiology, Protein Kinase C physiology, Tight Junctions physiology
- Abstract
In mouse early development, cell contact patterns regulate the spatial organization and segregation of inner cell mass (ICM) and trophectoderm epithelium (TE) during blastocyst morphogenesis. Progressive membrane assembly of tight junctional (TJ) proteins in the differentiating TE during cleavage is upregulated by cell contact asymmetry (outside position) and suppressed within the ICM by cell contact symmetry (inside position). This is reversible, and immunosurgical isolation of the ICM induces upregulation of TJ assembly in a sequence that broadly mimics that occurring during blastocyst formation. The mechanism relating cell contact pattern and TJ assembly was investigated in the ICM model with respect to PKC-mediated signaling and gap junctional communication. Our results indicate that complete cell contact asymmetry is required for TJ biogenesis and acts upstream of PKC-mediated signaling. Specific inhibition of two PKC isoforms, PKCdelta and zeta, revealed that both PKC activities are required for membrane assembly of ZO-2 TJ protein, while only PKCzeta activity is involved in regulating ZO-1alpha+ membrane assembly, suggesting different mechanisms for individual TJ proteins. Gap junctional communication had no apparent influence on either TJ formation or PKC signaling but was itself affected by changes of cell contact patterns. Our data suggest that the dynamics of cell contact patterns coordinate the spatial organization of TJ formation via specific PKC signaling pathways during blastocyst biogenesis.
- Published
- 2005
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46. Insulin and human chorionic gonadotropin cause a shift in the balance of sterol regulatory element-binding protein (SREBP) isoforms toward the SREBP-1c isoform in cultures of human granulosa cells.
- Author
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Richardson MC, Cameron IT, Simonis CD, Das MC, Hodge TE, Zhang J, and Byrne CD
- Subjects
- CCAAT-Enhancer-Binding Proteins drug effects, Cells, Cultured, DNA Primers, DNA, Complementary genetics, DNA-Binding Proteins drug effects, Fatty Acid Synthases genetics, Fatty Acids, Nonesterified metabolism, Female, Fertilization in Vitro, Granulosa Cells drug effects, Humans, Insulin-Like Growth Factor Binding Protein 1 metabolism, Progesterone metabolism, RNA, Messenger genetics, Sterol Regulatory Element Binding Protein 1, Sterol Regulatory Element Binding Protein 2, Transcription Factors drug effects, CCAAT-Enhancer-Binding Proteins genetics, Chorionic Gonadotropin pharmacology, DNA-Binding Proteins genetics, Granulosa Cells metabolism, Insulin pharmacology, Transcription Factors genetics
- Abstract
The isoforms of sterol regulatory element-binding proteins (SREBP) (1a, 1c, and 2) are key transcriptional regulators of lipid biosynthesis. We examined their regulation by gonadotropin and insulin in human granulosa cells. After removal of leukocytes, granulosa cells were exposed to hormonal additions for 16 h starting on d 2 of culture. Progesterone, lactate, and IGF binding protein-1 were measured in culture medium and cellular mRNA measured by competitive RT-PCR. Addition of human chorionic gonadotropin (hCG) (100 ng/ml) stimulated progesterone production (7.0-fold, P < 0.001 vs. control), whereas lactate was increased by hCG (1.6-fold, P < 0.001) and insulin (1.4-fold, P < 0.001; 1000 ng/ml). Insulin decreased IGF binding protein-1 production by 85% (P < 0.001). There were no significant effects on the expression of SREBP-1a but significant increases in mRNA for SREBP-1c with insulin (6.3-fold), hCG (10.4-fold) and in combination (15.2-fold; P < 0.01 for all comparisons). No consistent effects on SREBP-2 were observed. The expression of mRNA for fatty acid synthase, a target gene for SREBP-1c, was increased by hCG (24-fold, P = 0.006) and insulin (19-fold, P = 0.024), which also increased the level of cellular, total fatty acid (1.34-fold; P = 0.03). Thus, hCG and insulin cause a switch toward expression of the SREBP-1c isoform with consequent effects on fatty acid synthesis. We suggest that high circulating insulin, associated with clinically defined insulin resistance, may up-regulate SREBP-1c expression in the ovary.
- Published
- 2005
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47. Low serine hydroxymethyltransferase activity in the human placenta has important implications for fetal glycine supply.
- Author
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Lewis RM, Godfrey KM, Jackson AA, Cameron IT, and Hanson MA
- Subjects
- Animals, Birth Weight, Carbon Radioisotopes, Female, Humans, Pregnancy, Rats, Rats, Wistar, Serine pharmacokinetics, Sheep, Species Specificity, Fetal Development physiology, Glycine metabolism, Glycine Hydroxymethyltransferase metabolism, Placenta enzymology
- Abstract
Glycine is essential for fetal development, but in both sheep and human pregnancy, little is transported directly from the mother to the fetus, indicating that fetal glycine is derived from other sources. In the sheep, placental conversion of maternal serine by serine hydroxymethyltransferase (SHMT) provides almost all the glycine transported to the fetus. Although mRNA for mitochondrial and cytoplasmic SHMT has been detected in human placenta, it is not known whether substantial placental conversion of serine to glycine occurs in species other than sheep. We determined SHMT activity in human, rat, and sheep placenta by measuring conversion of [3-(14)C]serine to (14)C-methylene tetrahydrofolate. Compared with term human placenta, SHMT activity per gram of placenta was 5.1-fold higher in term rat placenta and 24.1-fold higher in term sheep placenta. In sheep placenta, SHMT activity per gram of placenta increased 2.1-fold between mid-gestation and term. In human placenta, placental SHMT activity was similar 8 wk post conception and at term. The low activity of SHMT in the human and rat placenta suggests that, unlike in the sheep, placental conversion of serine to glycine is not a major source of fetal glycine in these species.
- Published
- 2005
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48. Progesterone inhibits insulin-like growth factor binding protein-1 (IGFBP-1) production by explants of the Fallopian tube.
- Author
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Davies S, Richardson MC, Anthony FW, Mukhtar D, and Cameron IT
- Subjects
- Adult, Enzyme-Linked Immunosorbent Assay, Estradiol pharmacology, Fallopian Tubes cytology, Fallopian Tubes drug effects, Female, Humans, Insulin pharmacology, Insulin-Like Growth Factor Binding Protein 1 genetics, Middle Aged, Progesterone physiology, RNA, Messenger analysis, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction, Tissue Culture Techniques, Fallopian Tubes metabolism, Insulin-Like Growth Factor Binding Protein 1 biosynthesis, Progesterone pharmacology
- Abstract
The Fallopian tube provides the environment for early embryo growth, a process which is influenced by insulin-like growth factors (IGFs) in the tubal fluid. Whether the bioavailability of tubal IGFs is modulated by locally produced IGF-binding protein (IGFBP-1) is not clear. An explant culture system from human Fallopian tube mucosa was, therefore, developed enabling the potential for IGFBP-1 production by this tissue to be examined directly. Initial characterization of the system established that the explants maintained responsiveness to steroids. Thus, oviduct-specific glycoprotein production, a major product of the oviduct in vivo, continued to be made via an estrogen-sensitive pathway in the culture. The presence of mRNA for IGFBP-1 was established within the explants by the use of quantitative RT-PCR and IGFBP-1 protein was measured by enzyme-linked immunosorbent assay. Although insulin and estradiol had no consistent effect on IGFBP-1, addition of progesterone had a significant inhibitory effect on IGFBP-1 production, both at the mRNA and protein levels. A dose-range of progesterone revealed an incremental inhibitory effect of progesterone on IGFBP-1 output (maximal effect, 25-50 nmol/l), consistent with physiological inhibition of this process during the luteal phase. We suggest that progesterone might, therefore, play a role in controlling the bioavailability of IGFs to the embryo during early development within the Fallopian tube.
- Published
- 2004
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49. Specific PKC isoforms regulate blastocoel formation during mouse preimplantation development.
- Author
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Eckert JJ, McCallum A, Mears A, Rumsby MG, Cameron IT, and Fleming TP
- Subjects
- Animals, Blastocyst cytology, Cell Differentiation physiology, Cell Membrane metabolism, Culture Techniques, Female, Isoenzymes chemistry, Isoenzymes genetics, Membrane Proteins metabolism, Mice, Peptides genetics, Peptides metabolism, Phosphoproteins metabolism, Protein Kinase C chemistry, Protein Kinase C genetics, Sodium-Potassium-Exchanging ATPase metabolism, Tight Junctions metabolism, Zonula Occludens-1 Protein, Zonula Occludens-2 Protein, Blastocyst metabolism, Cell Communication physiology, Isoenzymes metabolism, Morphogenesis, Protein Kinase C metabolism, Signal Transduction physiology
- Abstract
During early mammalian development, blastocyst morphogenesis is achieved by epithelial differentiation of trophectoderm (TE) and its segregation from the inner cell mass (ICM). Two major interrelated features of TE differentiation required for blastocoel formation include intercellular junction biogenesis and a directed ion transport system, mediated by Na+/K+ ATPase. We have examined the relative contribution of intercellular signalling mediated by protein kinase C (PKC) and gap junctional communication in TE differentiation and blastocyst cavitation. The distribution pattern of four (delta, theta, iota/lambda, zeta) PKC isoforms and PKCmicro/PKD1 showed partial colocalisation with the tight junction marker ZO-1alpha+ in TE and all four PKCs (delta, theta, iota/lambda, zeta) showed distinct TE/ICM staining patterns (predominantly at the cell membrane within the TE and cytoplasmic within the ICM), indicating their potential contribution to TE differentiation and blastocyst morphogenesis. Specific inhibition of PKCdelta and zeta activity significantly delayed blastocyst formation. Although modulation of these PKC isoforms failed to influence the already established programme of epithelial junctional differentiation within the TE, Na+/K+ ATPase alpha1 subunit was internalised from membrane to cytoplasm. Inhibition of gap junctional communication, in contrast, had no influence on any of these processes. Our results demonstrate for the first time that distinct PKC isotypes contribute to the regulation of cavitation in preimplantation embryos via target proteins including Na+/K+ ATPase.
- Published
- 2004
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50. PKC signalling regulates tight junction membrane assembly in the pre-implantation mouse embryo.
- Author
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Eckert JJ, McCallum A, Mears A, Rumsby MG, Cameron IT, and Fleming TP
- Subjects
- Animals, Blastocyst ultrastructure, Culture Techniques, Dose-Response Relationship, Drug, Enzyme Activation, Female, Immunohistochemistry methods, Indoles pharmacology, Intracellular Membranes metabolism, Intracellular Membranes ultrastructure, Lactams pharmacology, Membrane Proteins metabolism, Mice, Mice, Inbred Strains, Microscopy, Confocal, Phosphoproteins metabolism, Protein Kinase C antagonists & inhibitors, Tight Junctions ultrastructure, Zonula Occludens-1 Protein, Zonula Occludens-2 Protein, Blastocyst metabolism, Protein Kinase C metabolism, Signal Transduction physiology, Tight Junctions metabolism
- Abstract
Epithelial differentiation including tight junction (TJ) formation occurs exclusively within the trophectoderm (TE) lineage of the mouse blastocyst. Here we examine mechanisms by which TJ protein membrane assembly might be regulated by protein kinase C (PKC) in the embryo. To overcome the inherent staging asynchrony of individual blastomeres within intact embryos, we have used isolated inner cell masses (ICMs) from early blastocysts to induce epithelial differentiation in their outer cells responding to their new cell contact pattern. Two TJ proteins examined retain their order of membrane assembly in isolated ICMs in culture as during normal development (early-assembling ZO-2 and late-assembling ZO-1alpha(+)), but this process is highly accelerated. Using six chemical modulators of PKC activity, we show here that PKC signalling is involved in the regulation of TJ membrane assembly. While indolactam-mediated PKC activation stimulates membrane assembly of both TJ proteins, TPA-mediated PKC activation stimulates only that of ZO-1alpha(+). The PKC inhibitors Ro-31-8220, Ro-31-8425 and Gö 6983 suppress the stimulatory effect of both PKC activators on membrane assembly to varying extents according to inhibitor and TJ protein examined. Gö 6983 similarly inhibits ZO-2 and ZO-1alpha(+) membrane assembly. PKC inhibition by Gö 6976 appeared to stimulate TJ membrane assembly. Despite the broad PKC isotype specificity of the inhibitors used, these data suggest that the two TJ proteins are differently regulated by PKC isotypes or subfamilies. As Gö 6983 uniquely affects aPKC (particularly PKCzeta) and we find that both PKCdelta and zeta relocate upon activator treatment to colocalise partially with the TJ proteins in isolated ICMs, we suggest that at least PKCdelta and zeta may play a central role in regulating TJ membrane assembly.
- Published
- 2004
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