Unusual case of initial failure of pacemaker implantation.

Central venous obstruction sufficient to prevent primary pacemaker implantation is rare. We report on such a patient in whom removal of a very large retrosternal goitre led to subsequent procedural success.

Sex- and age-specific effects of nutrition in early gestation and early postnatal life on hypothalamo-pituitary-adrenal axis and sympathoadrenal function in adult sheep.

The early-life environment affects risk of later metabolic disease, including glucose intolerance, insulin resistance and obesity. Changes in hypothalamo-pituitary-adrenal (HPA) axis and sympathoadrenal function may underlie these disorders. To determine consequences of undernutrition in early gestation and/or immediately following weaning on HPA axis and sympathoadrenal function, 2- to 3-year-old Welsh Mountain ewes received 100% (C, n = 39) or 50% nutritional requirements (U, n = 41) from 1-31 days gestation, and 100% thereafter. From weaning (12 weeks) to 25 weeks of age, male and female offspring were then either fed ad libitum (CC, n = 22; UC, n = 19) or were undernourished (CU, n = 17; UU, n = 22) such that body weight was reduced to 85% of their individual target, based on a growth trajectory calculated from weights taken between birth and 12 weeks. From 25 weeks, ad libitum feeding was restored for all offspring. At 1.5 and 2.5 years, adrenocorticotropic hormone (ACTH) and cortisol concentrations were measured at baseline and in response to corticotropin-releasing factor (CRF) (0.5 microg kg(1)) plus arginine vasopressin (AVP) (0.1 microg kg(1)). At 2.5 years, HPA axis and sympathoadrenal (catecholamine) responses to a transport and isolation stress test were also measured. In females, post-weaning undernutrition reduced pituitary output (ACTH) but increased adrenocortical responsiveness (cortisol:ACTH area under curve) during CRF/AVP challenge at 1.5 years and increased adrenomedullary output (adrenaline) to stress at 2.5 years. In males, cortisol responses to stress at 2.5 years were reduced in those with slower growth rates from 12 to 25 weeks. Early gestation undernutrition was associated with increased adrenocortical output in 2.5-year-old females only. Pituitary and adrenal responses were also related to adult body composition. Thus, poor growth in the post-weaning period induced by nutrient restriction has sex- and age-specific effects on HPA and sympathoadrenal function. With altered glucose tolerance previously reported in this model, this may have long-term detrimental effects on metabolic homeostasis and cardiovascular function.

Mismatched pre- and postnatal nutrition leads to cardiovascular dysfunction and altered renal function in adulthood.

The early life environment has long-term implications for the risk of developing cardiovascular (CV) disease in adulthood. Fetal responses to changes in maternal nutrition may be of immediate benefit to the fetus, but the long-term effects of these adaptations may prove detrimental if nutrition in postnatal life does not match that predicted by the fetus on the basis of its prenatal environment. We tested this predictive adaptive response hypothesis with respect to CV function in sheep. We observed that a mismatch between pre- and postnatal nutrient environments induced an altered CV function in adult male sheep that was not seen when environments were similar. Sheep that received postnatal undernutrition alone had altered growth, CV function, and basal hypothalamo-pituitary-adrenal axis activity in adulthood. Prenatal undernutrition induced greater weight gain by weaning compared with the prenatal control diet, which may provide a reserve in the face of a predicted poor diet in later life. In an adequate postnatal nutrient environment (i.e., relatively mismatched), these offspring exhibited cardiac hypertrophy and altered CV function in adulthood. These data support the concept that adult CV function can be determined by developmental responses to intrauterine nutrition made in expectation of the postnatal nutritional environment, and that if these predictions are not met, the adult may be maladapted and at greater risk of CV disease. Our findings have substantial implications for devising strategies to reduce the impact of a mismatch in nutrition levels in humans undergoing rapid socio-economic transitions in both developing and developed societies.

Nutritional challenges during development induce sex-specific changes in glucose homeostasis in the adult sheep.

The early-life environment has implications for risk of adult-onset diseases, such as glucose intolerance, insulin insensitivity, and obesity, effects that may occur with or without reduced birth weight. We determined the consequences of nutrient restriction in early gestation and early postnatal life and their interactions on postnatal growth, body composition, and glucose handling. Ewes received 100% (C, n = 39) or 50% nutritional requirements (U, n = 41) from 1 to 31 days gestation and 100% thereafter. Male and female offspring (singleton/twin) from C and U ewes were then fed either ad libitum (CC n = 22, UC n = 19) or to reduce body weight to 85% of target from 12 to 25 wk of age (CU n = 17, UU n = 22) and ad libitum thereafter. At 1.5 and 2.5 yr, glucose handling was determined by area under the curve (AUC) for glucose and insulin concentrations following intravenous glucose (0.5 g/kg body wt). Insulin sensitivity was determined at 2.5 yr following intravenous insulin (0.5 IU/kg). In females, postnatal undernutrition reduced (P < 0.05) glucose AUC at both ages, regardless of prenatal nutrition. Postnatal undernutrition did not affect insulin secretion in females but enhanced insulin-induced glucose disappearance in singletons. Poor early postnatal growth was associated with increased fat in females. In males, glucose tolerance was unaffected by undernutrition despite changes in insulin AUC dependent on age, treatment, and single/twin birth. Nutrition in early postnatal life has long-lasting, sex-specific effects on glucose handling in sheep, likely due, in females, to enhanced insulin sensitivity. Improved glucose utilization may aid weight recovery but have negative implications for glucose homeostasis and body composition over the longer term.