The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction

ABSTRACT The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work

Effectiviteit van interventies bij kinderen met migraine

Verhagen AP, Damen L, Bruijn JKJ, Berger MY, Passchier J, Koes BW. Effectiveness of interventions in children with migraine. Huisarts Wet 2006;49(3):123-9. Objective To assess the effectiveness and tolerance of treatment methods for episodes of migraine in children. Methods We performed a systematic review. Databases were searched from inception to June 2004, and references were checked. We selected randomised and controlled trials reporting the effects of symptomatic and prophylactic treatment methods in children with migraine, using headache features as outcome measure. Two independent reviewers assessed trial quality and extracted data. Quantitative and qualitative analyses were carried out according to type of intervention. Results A total of 49 trials (total 3296 patients) were included in this review, of which 16 studies (32.7%) were considered to be of high quality. Ten studies evaluated the effectiveness of acute medication. Compared to placebo, headache improved significantly for acetaminophen, ibuprofen, and nasal sumatriptan. No significant differences were found between acetaminophen and ibuprofen or nimesulide, and between oral sumatriptan, rizatriptan and dihydroergotamine compared to placebo. All medications were well tolerated, but significantly more adverse events were reported for nasal sumatriptan. Nineteen studies evaluated the effectiveness of non-pharmacological prophylactic treatments. When compared to waiting list control, headache improved significantly for relaxation, relaxation plus biofeedback, and relaxation plus biofeedback plus cognitive behavioural treatment. There is conflicting evidence regarding the use of oligoantigenic diets. Lastly, 20 studies evaluated the effectiveness of pharmacological prophylactic treatments. Compared to placebo, headache improved significantly for flunarizine medication. There is conflicting evidence for the use of propranolol. Nimodipine, clonidine, L-5HTP, trazodone and papaverine showed no efficacy when compared to placebo. Conclusions Acetaminophen and ibuprofen are effective symptomatic pharmacological treatments of episodes of migraine in children. Nasal spray sumatriptan is also effective, but more side effects are reported. A few treatments, such as relaxation and flunarizine, may be effective as prophylactic treatment for migraine in children

Neurobiological Interactions Between Stress and the Endocannabinoid System

Stress affects a constellation of physiological systems in the body and evokes a rapid shift in many neurobehavioral processes. A growing body of work indicates that the endocannabinoid (eCB) system is an integral regulator of the stress response. In the current review, we discuss the evidence to date that demonstrates stress-induced regulation of eCB signaling and the consequential role changes in eCB signaling have with respect to many of the effects of stress. Across a wide array of stress paradigms, studies have generally shown that stress evokes bidirectional changes in the two eCB molecules, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), with stress exposure reducing AEA levels and increasing 2-AG levels. Additionally, in almost every brain region examined, exposure to chronic stress reliably causes a downregulation or loss of cannabinoid type 1 (CB1) receptors. With respect to the functional role of changes in eCB signaling during stress, studies have demonstrated that the decline in AEA appears to contribute to the manifestation of the stress response, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and increases in anxiety behavior, while the increased 2-AG signaling contributes to termination and adaptation of the HPA axis, as well as potentially contributing to changes in pain perception, memory and synaptic plasticity. More so, translational studies have shown that eCB signaling in humans regulates many of the same domains and appears to be a critical component of stress regulation, and impairments in this system may be involved in the vulnerability to stress-related psychiatric conditions, such as depression and posttraumatic stress disorder. Collectively, these data create a compelling argument that eCB signaling is an important regulatory system in the brain that largely functions to buffer against many of the effects of stress and that dynamic changes in this system contribute to different aspects of the stress response