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Hyperglycaemia is a main feature of diabetes, and this pathology is a main complication of pregnancy. Diabetic patients often require tighter glycaemic control in pregnancy, as glucose metabolism changes, and insulin dosages need to be adjusted. Throughout gestation, the placenta is therefore subjected to periods of hyperglycaemic insult. Thus, we wished to study how brief periods of hyperglycaemia affected the feto-placental vasculature, through study of important permeability molecules, pro-permeability VEGFa, anti-permeability VEGFb, and junctional stability molecule VE-cadherin. A 15mM concentration of glucose was chosen because it is a level seen postprandially in diabetic pregnancies. We explored this by explant and perfusion methods. We tested two chorionic villous explants methodologies to validate them for 4h and 24h duration studies, and found that a free-floating methodology which sought to replicate the in utero flow was not appropriate, as this resulted in high basal levels of endothelial VEGF and low junctional VE-cadherin, a feature that we hypothesised to be a wound healing response. Therefore, we chose the stationary explants methodology, with no simulation of flow, for our subsequent experiments. The stationary method, where chorionic villi were incubated with hyperglycaemia (15mM glucose) vs. euglycaemia (5mM glucose) for the two different durations (4h and 24h) revealed that 15mM glucose was affecting junctional stability and the pro-permeability molecule VEGF-A after a 24h hyperglycaemic insult, but that VEGF was not affected by 4h. Given that 4h is a physiologically important timepoint (representing a postprandial glucose peak seen in diabetic pregnancies), we continued with this timepoint in further experiments. Whilst we found no effect of 15mM glucose insult after a 4h incubation on total VEGF expression, we found that the recently discovered anti-permeability VEGFb splice variant was decreased in hyperglycaemia compared to euglycaemic explants. Furthermore, the there was a significant negative correlation between total VEGF and VEGFb levels, indicating that the ratio of the two molecules was changing in diabetic explants compared to normal explants. The diabetic explants showed no further down-regulation of VEGFb on 15mM glucose insult, indicating a tolerance of the diabetic placental vessels to hyperglycaemia. We then investigated whether total VEGF and/or VEGFb were important predictors of vascular dysfunction as measured by an increased in leakage to 76Mr dextran-TRITC tracer in a well established perfusion model. The vascular bed was perfused with 15mM glucose administered to the maternal circuit. After a 3h hyperglycaemic perfusion, we observed high total VEGF, low VEGFb, and a loss of VE-cadherin from the endothelial junctions. These changes corresponded to a mild increase in leakage to 76Mr dextran tracer measured by counting vessels showing 'hotspots' of tracer at perivascular regions (18% of vessels leakage in the hyperglycaemic perfusions vs. 10% leakage in the euglycaemic perfusions). The percentage of vessels exhibiting tracer leakage showed a significant negative correlation with VEGFb (Spearman r value -0.8857) but not total VEGF, indicating that the former may be an important predictor of vascular dysfunction. It would be clinically important to be able to predict placental vascular dysfunction in diabetic pregnancies. Further experiments are needed to see whether the VEGFa/VEGFb ratio can predict vascular leakage under hyperglycaemia and the other main feature of diabetic pregnancies, hyperinsulinaemic insult, and whether the hyperglycaemic insult resulting in the diabetic phenotype is reversible upon euglycaemic conditions being restored. Our studies so far have shown that the diabetic phenotype can be partly replicated, in terms of vascular leakage, with a single 15mM hyperglycaemic insult. Chronic insult may well prove to result in the fully leaky vessels observed in diabetic placentae. VEGFb might be an important predictor of this leakage, and may be clinically used for assessment of risks in diabetic pregnancies.

Links between declining human male fertility (decreased sperm counts, increased incidence of both testicular cancer and genital abnormalities) and the increasing prevalence of endocrine disrupting chemicals (EDCs) in the environment have been reported. We aim to characterise the key developmental processes occurring during human fetal gonad development. Human fetal testis development was characterised by a transient increase in interstitial area proliferation between 13-19 weeks which was accompanied by an increase in steroidogenic acute regulatory protein (StAR) and steroidogenic enzymes. Androgen receptor was expressed by the peritubular myoid cells which had a high bcl-2:bax ratio, indicative of cell survival. Estrogen receptors ( and ) were localised to distinct cell populations. In the ovine gonad similar developmental processes occurred, and comparison with human ovarian development demonstrated interesting parallels. After optimisation, the explant culture system revealed that exposure to the insecticidal EDC dieldrin, at low (<1 ppb) doses reduced LH-stimulated testosterone output in the human fetal testis. This was accompanied by dose-specific changes to the testis proteome, alterations in bcl-2:bax ratios in favour of apoptosis and a down-regulation in StAR expression relative to the LH-treated controls. In conclusion, the processes of proliferation apoptosis, steroidogenesis and steroid action are crucial during fetal gonad development. We demonstrated that in utero exposure to dieldrin may cause reproductive dysfunction in adult life due to reduced steroidogenesis in the fetal gonad; mediated through a down-regulation in StAR expression and alterations in the regulation of gonadal apoptosis.

This thesis investigates the effect of body composition on insulin resistance and the impact of supplementation with nutritional support or carbohydrate treatment. Insulin resistance occurs as a response to a number of stressors, including surgery. However, the mechanism underlying the development of insulin resistance is as yet unclear. Adipose tissue distribution appears to play a role in the development of insulin resistance and obesity-related complications. In obese and non-obese patients undergoing open abdominal surgery who received preoperative carbohydrate or placebo, there was a significant fall in perioperative insulin sensitivity and changes in the expression of genes relating to carbohydrate and fat oxidation. There was no influence of perioperative carbohydrate or obesity on change in insulin sensitivity. Patients undergoing neoadjuvant chemotherapy for oesophageal cancer underwent pre and post chemotherapy assessment of insulin sensitivity and body composition. There was a significant reduction in insulin sensitivity despite minimal change in body composition and adequate nutritional intake. These studies have provided further information about the optimal methods for assessment of insulin sensitivity and body composition as well as an insight into mechanisms underlying the association between body composition and insulin sensitivity.

Background and aims Untreated stress-induced hyperglycaemia in critically ill patients has been associated with harmful effects, which can even be fatal. Current evidence about the optimal glycaemic targets, and the most effective and safest methods of glycaemic control (GC) in intensive care units (ICU), is contradictory. GlyCon study aimed to investigate the effectiveness, efficiency and safety of the monitoring and insulin treatment methods for GC implemented in the seven ICUs of an NHS ICU network in the UK. In addition, GlyCon study also aimed to explore the contents of the local protocols for GC of these ICUs, as well as the views of ICU professionals about several aspects of GC. Methodology A multi-method study was undertaken, comprising three sub‑studies: (1) a document review of the protocols for GC designed by and implemented at each of the participating ICUs, using techniques of inductive content analysis and descriptive statistics; (2) an online survey to ICU medical and nursing staff, on their opinion about effective GC, and deviations from protocol instructions, which was analysed using descriptive statistics and logistic regression; (3) A retrospective study about the methods and outcomes of GC, based on a review of electronic and manual medical records of a stratified random sample of 146 patients admitted to the seven participating ICUs during 2012 and 2013. The main analyses of association between the exposures and the primary outcome measure (percentage of time with glycaemic levels of 4‑10mmol/L, or TIR, which was transformed into the odds of being within that range at any time, or odds of IR), were mainly based on generalised estimating equations using the logit link, and autoregressive correlation structure. Secondary outcome measures of time‑efficiency and safety were also investigated, and analysed using univariate statistics and multiple log‑linear regression. Results The protocols for GC implemented in the seven ICUs differed greatly in their target patients, target glycaemic levels, recommended methods for monitoring, and insulin titration algorithms, among others. Most of the 40 respondents to the survey agreed that TIR≥75% constitutes good GC and TIR < 50% constitutes poor GC. Opinions were divided on intermediate levels of TIR, with professionals having more experience in intensive care tending to rate such intermediate TIR as poor GC more often than their less experienced colleagues. Most of the proposed protocol deviations were considered as major by at least two thirds of the respondents. Professionals’ role (nurse vs. physician) and their number of years of experience were significantly associated with different views. The blood glucose (BG) monitoring frequencies and insulin hourly dosages, at each glycaemic status, differed by ICU, and between patients with and without diabetes. Non‑adherence to protocol instructions regarding BG monitoring and insulin infusion rates occurred more often than not. The median (IQR) TIR was 91% (81‑96%) and 56% (34‑71%) among patients without and with diabetes, respectively. A number of time-dependent and time-constant factors were associated with higher odds of IR at any time. Time-constant protective factors included: having spent more than 20% of admission time receiving insulin during hyperglycaemia, certain ICU protocols, and lower levels of severity on admission. Time-dependent protective factors were: the number of hours from admission, and the dobutamine and insulin hourly dosages. Time-dependent detrimental factors were: non‑adherence to protocol insulin instructions, the hourly nutritional energy administered, and the hourly dosage of certain drugs, including adrenaline and hydrocortisone. Conclusions Protocols for GC, practice of GC, and outcomes of GC, all differed significantly across hospitals. Some protocols seemed more effective, time‑efficient or safe than others, but there was a high incidence of non‑adherence to protocol instructions in all ICUs. This contrasts with professionals rating deviations from protocols as major, more often than not. Certain monitoring and insulin treatment methods for GC were more effective, and some were more time‑efficient than others, particularly among patients without diabetes. There is a clear need for protocols to include different recommendations for patients with diabetes, as well as to formally emphasise the importance of GC also in patients without diabetes. ICU multidisciplinary teams should be involved in the development of these protocols, and their views should be accounted for in research studies about the effectiveness of GC in the ICU.

Corticosteroid medicines have anti-inflammatory and immunosuppressant effects. Corticosteroids are prescribed for a wide range of conditions in children. The duration of treatment ranges from a few days (short course) to long term. They are usually given orally in the different dosage form of tablets, syrup or soluble tablets. There are a wide range of adverse drug reactions (ADRs) associated with corticosteroids. This thesis initially evaluates the incidence of each individual ADR in children using systematic reviews. Prospective studies of palatability and pharmacoepidemiology using different methods are also used to evaluate aspects of using corticosteroids in children in Saudi Arabia and the UK. A systematic review of the toxicity of short-course oral corticosteroids in children was conducted. Six electronic databases were searched for articles that evaluated the toxicity of oral corticosteroids in children for up to and including 14 days of treatment. Thirty eight articles including 22 randomised controlled trials (RCTs). The review found that the three most frequent ADRs were vomiting, behavioural changes and sleep disturbance, with incidence rates of 4.3 – 5.4% of patients. Infection was one of the most serious ADRs. A systematic review of the toxicity of long-course oral corticosteroids in children was conducted. One hundred studies including 33 prospective cohort studies and 21 RCTs met the inclusion criteria. The review found that the three most frequent ADRs were weight gain, growth retardation and Cushingoid features, with incidence rates of 18.1 – 21.1% of patients. Infection was one of the most serious ADRs, with twenty one deaths. Hypothalamic-pituitary-adrenal (HPA) axis suppression was detected in 249 of 429 patients in whom it was measured. Based on the findings that were highlighted from the systematic review, a prospective observational/interview study was performed. This study evaluated the tolerability and palatability of oral prednisolone and dexamethasone in children in Saudi Arabia and the UK. Palatability was evaluated by asking patient/parent’s opinions of the taste and acceptability of the medication. Tolerability in particular nausea, vomiting and abdominal pain was evaluated by direct questioning of the patient/parents after each administration. Dexamethasone sodium phosphate solution was the most palatable preparation. Prednisolone base tablets were rated the least palatable and were also the least well tolerated. Palatability scores seemed to improve with second doses. A prospective pharmacoepidemiological study of corticosteroids use in Saudi Arabian children was conducted. This study aimed to evaluate the prescribing pattern of corticosteroids for children in the Emergency, outpatient clinics and paediatric wards in the Gurayat General Hospital (GGH) in Saudi Arabia. A total of 1000 patients were approached for the study. Most of whom were asthmatic, eczema, bronchiolitis, and croup patients. A total of 1209 prescriptions were prescribed from different departments. The three most frequently prescribed corticosteroids medications were hydrocortisone ampoules (24.4%), prednisolone tablets (16.4%) and mometasone furoate ointment (9%). This research has contributed to the field of corticosteroids in children by providing more information about the most common and serious ADRs and determining their relative risk levels.

<p>'Endocrine disrupting chemicals (EDCs) are compounds found in the environment that have the potential to disrupt normal endocrine function. Estrogenic EDCs (e-EDCs) is a subclass of EDCs and is defined as substances contaminating the environment that may mimic or inhibit the effect of endogenous estrogen and therefore may influence developmental and reproductive health in humans and animals. The aim of this study was to develop, validate and implement a battery of in vitro and in vivo screening assays for e-EDCs. The study was concluded by implementing this battery of assays to assess the Eerste River, South Africa at three sampling sites, namely Jonkershoek, Stellenbosch sewage treatment works (STW) effluent and Spier for e-EDCs. The control site, Jonkershoek contained very low levels of estrone. Water from this site showed no estrogenic activity when the E-screen and the ER_ induction in MCF-7 cells. Some of the water samples collected at this site tested positive for estrogenicity when analysed with the juvenile tilapia VTG assay, whereas the rest were negative. The estrone levels in the sewage effluent extracts as well as Spier were significantly higher. The assay using ER_ protein induction by the MCF-7 cell line, the MCF-7 proliferation assay and the tilapia in vivo screen for estrogenicity showed that these samples are estrogenic. Results obtained for estrogenicity at the three different sampling sites for each of the assays in the battery were comparable. In this study we developed, validated and also implemented a battery of assays encompassing both in vitro and in vivo assays, based on different biological mechanisms, to detect estrogenic EDCs. To our knowledge, this is the first study that has used a battery of bioassays to specifically assess a South Africa river for estrogenicity...'</p>

Graduation date: 1991

Thesis (Ph. D.)--University of Hong Kong, 1987.

Background: Newer multimodality therapeutic interventions have resulted in dramatic survival rates in childhood cancers. However diverse treatment related morbidities affect the long term survivors. An Endocrine complication comprises 20-40% of these morbidities and affects the hypothalamic pituitary axis, growth, pubertal progression, fertility, bone health and glucose homeostasis. Objectives: The aim of our study was to enumerate and evaluate the frequency of endocrine complications arising as a late effect of treatment in childhood cancer survivors. Risk factors likely to be associated with these complications were also evaluated. Methodology: Retrospective analysis of medical records from the Long Term Endocrine Follow up clinic in the Department of Paediatrics and Adolescent Medicine of Queen Mary Hospital was done. Patients with a primary diagnosis of Cancer and Langerhans cell histiocytosis with endocrine sequelae arising from various treatment modalities who have survived 5 years after diagnosis were included in the study. Those who had endocrine complications arising from various treatment modalities for Thalassemia’s, Immunodeficiency’s were excluded from the study Results: 135 cases were included in the study and 27 were excluded. Leukemia and Brain tumor survivors were the majority accounting for 40% and 26.67% respectively. ALL formed majority of leukemia survivors, Medulloblastoma survivors accounted for 50% of brain tumor survivors. Most common endocrine problem was Hypogonadism in 51.1% of cases, followed by growth disturbances in 40%, Thyroid dysfunction in 23% and Hyperlipidemias in 18.5%. Pubertal problems, Central Diabetes Insipidus, Adrenal insufficiency, Obesity, Altered glucose homeostasis were rest of the problems in small frequencies. PHGN (Primary Hypogonadism) was present in 91.3% and mostly in prepubertal males. PHGN was statistically associated with Leukemia survivors with OR-2.06 (1.02- 4.15), p value 0.04. The risk factors associated were exposure to alkylating agents, radiotherapy, TBI prior to transplant. SHGN (Secondary HGN) was statistically associated with Brain tumor survivor OR - 15.8 (1.7-140.5), p value 0.013. Cranial irradiation was the major risk for SHGN. PGV (Poor growth velocity) was the major growth problem.GHD (Growth Hormone Deficiency) had a highly significant association with Brain tumors (p value ˂ 0.0001), and significantly associated when all 3 modalities of treatment given together (p value 0.01). Risk factors for GHD were cranial radiotherapy, exposure to cyclophosphamide and TBI. PH (Primary Hypothyroidism) had highly significant association with craniospinal radiotherapy (p value ˂ 0.0001), and significantly associated with brain tumors. Similar results were observed in patients of CH (Central Hypothyroidism). Hyperlipidemias were present in 18% with no statistical correlation with the type of cancer. Brain tumor survivors had a significant association of GHD, PH, CH, SHGN and CDI. Leukemia survivors had significant association with GHD and PHGN. Conclusions: Endocrine problems are frequent manifestations of late effects of cancer related treatments. Early detection and intervention of these potentially treatable problems could be done through structured long term surveillance. Increasing awareness among health care professionals to anticipate problems in suspected patients and education of patients would optimize health care and quality of life. / published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Medical Sciences