Prevalence of gastrointestinal symptoms in Angelman syndrome.

Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability, expressive speech impairment, movement disorder, epilepsy, and a happy demeanor. Children with AS are frequently reported to be poor feeders during infancy and as having gastrointestinal issues such as constipation, reflux, and abnormal food related behaviors throughout their lifetime. To assess the prevalence of gastrointestinal disorders in individuals with AS, we retrospectively analyzed medical records of 120 individuals seen at the Angelman Syndrome Clinic at Massachusetts General Hospital and 43 individuals seen at the University of North Carolina Comprehensive Angelman Clinic. The majority of patients' medical records indicated at least one symptom of gastrointestinal dysfunction, with constipation and gastroesophageal reflux disease (GERD) the most common. Other gastrointestinal issues reported were cyclic vomiting episodes, difficulty swallowing, excessive swallowing, and eosinophilic esophagitis. Upper gastrointestinal symptoms such as GERD, swallowing difficulties, cyclic vomiting, and eosinophilic esophagitis were more common in those with deletions and uniparental disomy, likely related to the involvement of multiple genes and subsequent hypotonia. The frequency of constipation is consistent among all genetic subtypes while early feeding issues appear to mainly affect those with deletions. Caregivers and healthcare providers should be aware of the high prevalence of these issues, as proper treatment may improve not only gastrointestinal dysfunction but also sleep and behavioral issues.

Effects of predictable and unpredictable food restriction on the stress response in molting and non-molting European starlings (Sturnus vulgaris).

This study tested whether an ethologically relevant stressor, a three-week period of food restriction where food was unavailable for four hours a day, caused chronic stress in molting and non-molting captive European starlings. Although all birds increased weight during the Food Restriction period, only non-molting birds increased food intake. Morning baseline heart rates increased during the Food Restriction period and all birds showed a decrease in heart rate when food was absent from the cage. In non-molting birds, there were no differences in either baseline or stress-induced corticosterone (CORT) concentrations, whereas molting birds showed attenuated baseline CORT, stress-induced CORT, and fecal glucocorticoid metabolite levels over the Food Restriction period. Although several parameters, such as increased morning heart rate, are consistent with chronic stress, the majority of these data suggest that restricting food availability is not chronically stressful. Furthermore, making the timing of food removal less predictable by randomizing when food was removed during the day did not enhance any of the above responses, but did alter the frequency of maintenance and feeding behaviors. In conclusion, starlings appear resistant to developing symptoms of chronic stress from repeated food restriction.

The effect of learning on heart rate and behavior of European starlings (Sturnus vulgaris).

Wild-caught European starlings (Sturnus vulgaris) were exposed to a learning task to determine whether heart rate (HR) and behavior responses to the learning activated the sympathetic nervous system. Birds learned to discriminate between images of opposite convexity (concave and convex) based on shading cues in a closed economy (food only available through task completion). Once learned, the task was changed in three ways: (a) manipulating the angle and shape of the image; (b) altering the availability of the task; and (c) reversing the positive stimulus. HR, used as an index of catecholamine release, was measured during each change to determine whether having to alter previously established behaviors to learn new behaviors elicited a sympathetic response. Starlings decreased their HR during the initial discrimination training and did not alter their HR when presented with modified images or when the positive stimulus was reversed. However, HR increased when the task became unavailable and decreased upon its return, suggesting that preventing task performance was perceived as stressful. Birds also modified their behavior when tasks were changed. The number of trials per minute decreased during the reversal treatment, as did the success rate, suggesting that starlings may try to conserve energy when access to food diminishes. This is also supported by the decrease in perch hops per minute when the task was unavailable and the subsequent increase upon its return. Overall, these results suggest that learning per se does not activate the sympathetic nervous system and, therefore, is not a stressor for wild birds.