Background Aortic stenosis in the midgestation fetus with a normal-sized or dilated left ventricle predictably progresses to hypoplastic left heart syndrome when associated with certain physiological findings. Prenatal balloon aortic valvuloplasty may improve left heart growth and function, possibly preventing evolution to hypoplastic left heart syndrome. Methods and Results Between March 2000 and October 2008, 70 fetuses underwent attempted aortic valvuloplasty for critical aortic stenosis with evolving hypoplastic left heart syndrome. We analyzed this experience to determine factors associated with procedural and postnatal outcome. The median gestational age at intervention was 23 weeks. The procedure was technically successful in 52 fetuses (74%). Relative to 21 untreated comparison fetuses, subsequent prenatal growth of the aortic and mitral valves, but not the left ventricle, was improved after intervention. Nine pregnancies (13%) did not reach a viable term or preterm birth. Seventeen patients had a biventricular circulation postnatally, 15 from birth. Larger left heart structures and higher left ventricular pressure at the time of intervention were associated with biventricular outcome. A multivariable threshold scoring system was able to discriminate fetuses with a biventricular outcome with 100% sensitivity and modest positive predictive value. Conclusions Technically successful aortic valvuloplasty alters left heart valvar growth in fetuses with aortic stenosis and evolving hypoplastic left heart syndrome and, in a subset of cases, appeared to contribute to a biventricular outcome after birth. Fetal aortic valvuloplasty carries a risk of fetal demise. Fetuses undergoing in utero aortic valvuloplasty with an unfavorable multivariable threshold score at the time of intervention are very unlikely to achieve a biventricular circulation postnatally.
Oxidative stress may play a role in the pathophysiology of diabetes and cardiovascular disease, but little is known about antioxidant status among individuals with the metabolic syndrome who are at high risk for developing these conditions. Using data from the Third National Health and Nutrition Examination Survey (1988 -1994), we compared circulating concentrations of vitamins A, C, and E; retinyl esters; five carotenoids; and selenium in 8,808 U.S. adults aged >20 years with and without the metabolic syndrome. After adjusting for age, sex, race or ethnicity, education, smoking status, cotinine concentration, physical activity, fruit and vegetable intake, and vitamin or mineral use, participants with the metabolic syndrome had significantly lower concentrations of retinyl esters, vitamin C, and carotenoids, except lycopene. With additional adjustment for serum lipid concentrations, vitamin E concentrations were significantly lower in participants with the metabolic syndrome than those without the syndrome. Retinol concentrations were similar between the two groups. After excluding participants with diabetes, the results were very similar. Consumption of fruits and vegetables was also lower among people with the metabolic syndrome. Adults with the metabolic syndrome have suboptimal concentrations of several antioxidants, which may partially explain their increased risk for diabetes and cardiovascular disease.
Neurologic impairment is a major complication of complex congenital heart disease (CHD). A growing body of evidence suggests that neurologic dysfunction may be present in a significant proportion of this high-risk population in the early newborn period prior to surgical interventions. We recently provided the first evidence that brain growth impairment in fetuses with complex CHD has its origins in utero. Here, we extend these observations by characterizing global and regional brain development in fetuses with hypoplastic left heart syndrome (HLHS), one of the most severe forms of CHD. Using advanced magnetic resonance imaging techniques, we compared in vivo brain growth in 18 fetuses with HLHS and 30 control fetuses from 25.4-37.0 weeks of gestation. Our findings demonstrate a progressive third trimester fall-off in cortical gray and white matter volumes (P < 0.001), and subcortical gray matter (P < 0.05) in fetuses with HLHS. Significant delays in cortical gyrification were also evident in HLHS fetuses (P < 0.001). In the HLHS fetus, local cortical folding delays were detected as early as 25 weeks in the frontal, parietal, calcarine, temporal, and collateral regions and appear to precede volumetric brain growth disturbances, which may be an early marker of elevated risk for third trimester brain growth failure.
Background-Adverse neurodevelopmental outcome is an important source of morbidity in children with congenital heart disease (CHD). A significant proportion of newborns with complex CHD have abnormalities of brain size, structure, or function, which suggests that antenatal factors may contribute to childhood neurodevelopmental morbidity. Methods and Results-Brain volume and metabolism were compared prospectively between 55 fetuses with CHD and 50 normal fetuses with the use of 3-dimensinal volumetric magnetic resonance imaging and proton magnetic resonance spectroscopy. Fetal intracranial cavity volume, cerebrospinal fluid volume, and total brain volume were measured by manual segmentation. Proton magnetic resonance spectroscopy was used to measure the cerebral N-acetyl aspartate: choline ratio (NAA:choline) and identify cerebral lactate. Complete fetal echocardiograms were performed. Gestational age at magnetic resonance imaging ranged from 25 1 ⁄7 to 37 1 ⁄7 weeks (median, 30 weeks). During the third trimester, there were progressive and significant declines in gestational age-adjusted total brain volume and intracranial cavity volume in CHD fetuses relative to controls. NAA:choline increased progressively over the third trimester in normal fetuses, but the rate of rise was significantly slower (PϽ0.001) in CHD fetuses. On multivariable analysis adjusted for gestational age and weight percentile, cardiac diagnosis and percentage of combined ventricular output through the aortic valve were independently associated with total brain volume. Independent predictors of lower NAA:choline included diagnosis, absence of antegrade aortic arch flow, and evidence of cerebral lactate (PϽ0.001). Conclusions-Third-trimester fetuses with some forms of CHD have smaller gestational age-and weight-adjusted total brain volumes than normal fetuses and evidence of impaired neuroaxonal development and metabolism. Hemodynamic factors may play an important role in this abnormal development. (Circulation. 2010;121:26-33.)
How does a neuron, challenged by an increase in synaptic input, display a response that is independent of the initial level of activity? Here we show that both oxytocin and vasopressin cells in the supraoptic nucleus of normal rats respond to intravenous infusions of hypertonic saline with gradual, linear increases in discharge rate. In hyponatremic rats, oxytocin and vasopressin cells also responded linearly to intravenous infusions of hypertonic saline but with much lower slopes. The linearity of response was surprising, given both the expected nonlinearity of neuronal behavior and the nonlinearity of the oxytocin secretory response to such infusions. We show that a simple computational model can reproduce these responses well, but only if it is assumed that hypertonic infusions coactivate excitatory and inhibitory synaptic inputs. This hypothesis was tested first by applying the GABA(A) antagonist bicuculline to the dendritic zone of the supraoptic nucleus by microdialysis. During local blockade of GABA inputs, the response of oxytocin cells to hypertonic infusion was greatly enhanced. We then went on to directly measure GABA release in the supraoptic nucleus during hypertonic infusion, confirming the predicted rise. Together, the results suggest that hypertonic infusions lead to coactivation of excitatory and inhibitory inputs and that this coactivation may confer appropriate characteristics on the output behavior of oxytocin cells. The nonlinearity of oxytocin secretion that accompanies the linear increase in oxytocin cell firing rate reflects frequency-facilitation of stimulus-secretion coupling at the neurohypophysis.
Children and CHD patients treated with CRT have acute improvement in ventricular function, but implantation may require individualized planning and unconventional approaches. Future important goals include preimplant determination of CRT responders in pediatric and CHD patients, optimizing lead placement and programing, as well as long-term CRT device management issues.
This 13-week, double-blind study evaluated the efficacy and safety of the atypical antipsychotic paliperidone palmitate (recently approved in the United States) versus placebo administered as monthly gluteal injections (after two initial doses given 1 week apart) in acutely symptomatic patients with schizophrenia. Patients (N=388) were randomly assigned (1 : 1 : 1 : 1) to paliperidone palmitate 50, 100, or 150 mg eq. or placebo. As the 150 mg eq. dose was administered to fewer patients (n=30) than planned, meaningful and definitive conclusions cannot be drawn from the results of this group. The change from baseline in Positive and Negative Syndrome Scale total score at endpoint showed improvement in both paliperidone palmitate 50 and 100 mg eq. groups but was significant only in the 100 mg eq. group (P=0.019). The paliperidone palmitate 50 (P=0.004) and 100 mg eq. (P<0.001) groups showed significant improvement in the Personal and Social Performance score from baseline to endpoint versus placebo. Common adverse events (in >or=2% of patients in any group) more frequent with paliperidone palmitate 50 or 100 mg eq. than placebo (>or=5% difference) were headache, vomiting, extremity pain, and injection site pain. Treatment with paliperidone palmitate (100 mg eq.) was efficacious and all doses tested were tolerable.
When young suckle, they are rewarded intermittently with a let-down of milk that results from reflex secretion of the hormone oxytocin; without oxytocin, newly born young will die unless they are fostered. Oxytocin is made by magnocellular hypothalamic neurons, and is secreted from their nerve endings in the pituitary in response to action potentials (spikes) that are generated in the cell bodies and which are propagated down their axons to the nerve endings. Normally, oxytocin cells discharge asynchronously at 1–3 spikes/s, but during suckling, every 5 min or so, each discharges a brief, intense burst of spikes that release a pulse of oxytocin into the circulation. This reflex was the first, and is perhaps the best, example of a physiological role for peptide-mediated communication within the brain: it is coordinated by the release of oxytocin from the dendrites of oxytocin cells; it can be facilitated by injection of tiny amounts of oxytocin into the hypothalamus, and it can be blocked by injection of tiny amounts of oxytocin antagonist. Here we show how synchronized bursting can arise in a neuronal network model that incorporates basic observations of the physiology of oxytocin cells. In our model, bursting is an emergent behaviour of a complex system, involving both positive and negative feedbacks, between many sparsely connected cells. The oxytocin cells are regulated by independent afferent inputs, but they interact by local release of oxytocin and endocannabinoids. Oxytocin released from the dendrites of these cells has a positive-feedback effect, while endocannabinoids have an inhibitory effect by suppressing the afferent input to the cells.
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