Research Article
DEVELOPMENTAL PROGRAMMING OF OBESITY AND TYPE 2 DIABETES
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- MARK HEDLEY VICKERS, CINDA-LEE CUPIDO, PETER DAVID GLUCKMAN
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- Published online by Cambridge University Press:
- 01 February 2007, pp. 1-23
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Obesity and type 2 diabetes are serious health issues in the developed world and are becoming increasingly important on a global scale. Furthermore, the marked increases in both childhood obesity and type 2 diabetes will translate to further increases in adult obesity, diabetes and associated co-morbidities in the near future; as such it has been ranked as a critical public health threat. It is a widely held view that the primary cause of obesity is the development of an obesogenic environment, due to ease of access to highly calorific food and reduced energy expenditure in work and leisure activities. In addition there is strong evidence for a genetic component to human obesity with the identification of a number of genes associated with human obesity. However, on its own the genetic component of this condition cannot account for the dramatic increase in the prevalence of obesity in recent years. Of relevance and as highlighted by epidemiological and experimental studies, is the relationship between the periconceptual, fetal and early infant phases of life and the subsequent development of adult obesity. The terms “developmental programming” and the “Developmental Origins of Adult Health and Disease” are preferentially used to describe these relationships. Despite initial controversy when these relationships were first suggested, both prospective clinical and experimental studies have clearly shown that the propensity to develop abnormalities of cardiovascular, endocrine and metabolic homeostasis in adulthood are increased when fetal development has been adversely affected. This pathogenesis is not based on genetic defects but on altered gene expression seen as a result of fetal adaptation to an adverse intrauterine environment. The relative role of genetic versus environmental factors and the mechanisms underlying developmental programming remain speculative. It is generally argued that in response to an adverse intrauterine environment, the fetus adapts its physiological development to maximise its immediate chances for survival. Owing to the plasticity of the fetus, these adaptations may include resetting of metabolic homeostasis and endocrine systems and the down-regulation of growth, commonly reflected in an altered birth phenotype. It is thought that whilst these changes in fetal physiology (i.e. the prenatal environment) may be beneficial for short term survival in utero they may be maladaptive in postnatal life, contributing to poor health outcomes when offspring are exposed to catch-up growth, diet-induced obesity and other factors. The “predictive adaptive response” hypothesis proposes that the degree of mismatch between the pre- and postnatal environments is a major determinant of subsequent disease. This review will address recent work in animal models and observations in the clinical and epidemiological settings on in utero adaptations and subsequent development of obesity and type 2 diabetes.
PREMATURE CERVICAL CHANGE AND THE USE OF CERVICAL CERCLAGE
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- MANJU CHANDIRAMANI, ANDREW H SHENNAN
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- 01 February 2007, pp. 25-52
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Preterm birth and its subsequent consequences continue to be a major challenge worldwide. In the United States in 2004, 12.5% of infants were born preterm, making the annual societal economic burden associated with preterm birth in excess of $26.2 billion (and this is a modest estimate). Spontaneous preterm birth accounts for about 75% of all preterm births; however, at earlier gestations iatrogenic preterm birth accounts for a greater proportion of all preterm births; at 27–28 weeks 50% are iatrogenic. The proportion of babies transferred to the neonatal unit is more than 90% for those born before 33 completed weeks of gestation compared with 31% at 36 weeks; delivery between 33 completed weeks and 36 completed weeks has a relatively low morbidity and mortality. Nonetheless, 1 in 3 children born preterm but beyond 32 weeks have educational and behavioural problems at the age of 7, with 1 in 4 children born between 32 and 35 weeks requiring support from non-teaching assistants at school. Although more than 40% of babies at 35 completed weeks show signs of maturity, some still need ventilation at 38 completed weeks. Almost one-fifth of all infants born at less than 32 weeks gestation do not survive the first year of life.
DIAGNOSTIC MARKERS IN NEONATAL SEPSIS
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- HUGH S. LAM, PAK C NG
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- 01 February 2007, pp. 53-65
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Breakthroughs in the management of sick newborns, including exogenous surfactant therapy, advance ventilation techniques, inhaled nitric oxide, and use of antenatal corticosteroids have led to substantial improvements in the survival of vulnerable preterm infants. Neonatal clinicians now have access to an ever increasing armament of antimicrobial agents to help combat infections. However, even with the support of such advanced therapeutic modalities, strict infection control measures and low thresholds for use of broad-spectrum antibiotics, the threat of bacterial infections especially in the most susceptible group of preterm, very low birth weight (VLBW) infants have persisted. A recent survey suggests that a significant proportion of VLBW infants (21%) have at least one episode of late-onset culture proven sepsis during their stay in the neonatal unit. Infected infants require longer hospital stay and have higher risk of developing complications, such as bronchopulmonary dysplasia and adverse long-term neurodevelopment. Neonates with infection often present with subtle and non-specific signs of sepsis. Some may be asymptomatic at the initial stages of infection. Even those infants with signs may not be clinically distinguishable from patients suffering from transient tachypnoea of the newborn, respiratory distress syndrome, apnoea of prematurity or acute exacerbation of bronchopulmonary dysplasia, during early phases of the disease. Such presentations can lead to both delayed treatment of genuinely infected infants and indiscriminate use of antibiotics in non-infected cases, resulting in acceleration of emergence of bacterial resistance, alteration of patterns of bacterial infection, and inefficient treatment of septicaemia. Both early and late-onset infections are important causes of neonatal morbidity and mortality. Methods to assist neonatal clinicians diagnose infants in the early stages of infection are, therefore, highly desirable.
MATERNAL TEMPERATURE IN LABOUR
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- CLAIRE BAILEY, PHILIP J STEER
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- 01 February 2007, pp. 67-83
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In this review, we are concerned primarily with pyrexia (hyperthermia; increased maternal temperature in labour) as hypothermia is rare and usually iatrogenic (as in hypothermia for cardiac bypass surgery). We start by reviewing the factors determining maternal temperature, and how it can be measured. We move on to the effects of the commonest cause of maternal pyrexia in labour in modern obstetric practice in developed countries, epidural anaesthesia. We then discuss the most feared cause of maternal pyrexia in labour, chorioamnionitis.