223 research outputs found
Neuroanatomical dysmorphology of the medial superior olivary nucleus in sudden fetal and infant death
doi: 10.3389/fnhum.2012.00322 Neuroanatomical dysmorphology of the medial superior olivary nucleus in sudden fetal and infant deat
From Phineas Gage and Monsieur Leborgne to H.M.: Revisiting Disconnection Syndromes
On the 50th anniversary of Norman Geschwind's seminal paper entitled 'Disconnexion syndrome in animal and man', we pay tribute to his ideas by applying contemporary tractographymethods to understand whitematter disconnection in 3 classic cases that made history in behavioral neurology.We first documented the locus and extent of the brain lesion from the computerized tomography of Phineas Gage's skull and themagnetic resonance images of Louis Victor Leborgne's brain, Broca's first patient, and Henry Gustave Molaison. We then applied the reconstructed lesions to an atlas of white matter connections obtained from diffusion tractography of 129 healthy adults. Our results showed that in all 3 patients, disruption extended to connections projecting to areas distant from the lesion.We confirmed that the damaged tracts link areas that in contemporary neuroscience are considered functionally engaged for tasks related to emotion and decision-making (Gage), language production (Leborgne), and declarative memory (Molaison). Our findings suggest that even historic cases should be reappraised within a disconnection framework whose principles were plainly established by the associationist schools in the last 2 centuries
The age, origin and emplacement of the Tsiknias Ophiolite, Tinos, Greece
The Tsiknias Ophiolite, exposed at the highest structural levels of Tinos, Greece, represents a thrust sheet of Tethyan oceanic crust and upper mantle emplaced onto the AtticâCycladic Massif. We present new field observations and a new geological map of Tinos, integrated with petrology, THERMOCALC phase diagram modelling, UâPb geochronology and whole rock geochemistry, resulting in a tectonoâthermal model that describes the formation and emplacement of the Tsiknias Ophiolite and newly identified underlying metamorphic sole. The ophiolite comprises a succession of partially dismembered and structurally repeated ultramafic and gabbroic rocks that represent the Moho Transition Zone. A plagiogranite dated by UâPb zircon at 161.9 ± 2.8 Ma, reveals that the Tsiknias Ophiolite formed in a supraâsubduction zone setting, comparable to the âEastâVardar Ophiolitesâ, and was intruded by gabbros at 144.4 ± 5.6 Ma. Strongly sheared metamorphic sole rocks show a condensed and inverted metamorphic gradient, from partially anatectic amphibolites at PâT conditions of ca. 8.5 kbar 850â600 °C, downâstructural section to greenschistâfacies oceanic metasediments over ~250 m. Leucosomes generated by partial melting of the uppermost sole amphibolite, yielded a UâPb zircon protolith age of ca. 190 Ma and a highâgrade metamorphicâanatectic age of 74.0 ± 3.5 Ma associated with ophiolite emplacement. The Tsiknias Ophiolite was therefore obducted ~90 Myrs after it formed during initiation of a NEâdipping intraâoceanic subduction zone to the northeast of the Cyclades that coincides with Africa's plate motion changing from transcurrent to convergent. Continued subduction resulted in highâpressure metamorphism of the Cycladic continental margin ~25 Myrs later
Towards an International Consensus on the Prevention, Treatment, and Management of High-Risk Substance Use and Overdose among Youth
Background and Objectives: Now more than ever, there is an obvious need to reduce the overall burden of disease and risk of premature mortality that are associated with mental health and substance use disorders among young people. However, the current state of research and evidence-based clinical care for high-risk substance use among youth is fragmented and scarce. The objective of the study is to establish consensus for the prevention, treatment, and management of high-risk substance use and overdose among youth (10 to 24 years old). Materials and Methods: A modified Delphi technique was used based on the combination of scientific evidence and clinical experience of a group of 31 experts representing 10 countries. A semi-structured questionnaire with five domains (clinical risks, target populations, intervention goals, intervention strategies, and settings/expertise) was shared with the panelists. Based on their responses, statements were developed, which were subsequently revised and finalized through three iterations of feedback. Results: Among the five major domains, 60 statements reached consensus. Importantly, experts agreed that screening in primary care and other clinical settings is recommended for all youth, and that the objectives of treating youth with high-risk substance use are to reduce harm and mortality while promoting resilience and healthy development. For all substance use disorders, evidence-based interventions should be available and should be used according to the needs and preferences of the patient. Involuntary admission was the only topic that did not reach consensus, mainly due to its ethical implications and resulting lack of comparable evidence. Conclusions: High-risk substance use and overdoses among youth have become a major challenge. The systemâs response has been insufficient and needs substantial change. Internationally devised consensus statements provide a first step in system improvement and reform
Brain activity underlying negative self- and other-perception in adolescents: The role of attachment-derived self-representations
One of teenagers' key developmental tasks is to engage in new and meaningful relationships with peers and adults outside the family context. Attachment-derived expectations about the self and others in terms of internal attachment working models have the potential to shape such social reorientation processes critically and thereby influence adolescents' social-emotional development and social integration. Because the neural underpinnings of this developmental task remain largely unknown, we sought to investigate them by functional magnetic resonance imaging. We asked n = 44 adolescents (ages 12.01-18.84 years) to evaluate positive and negative adjectives regarding either themselves or a close other during an adapted version of the well-established self-other trait-evaluation task. As measures of attachment, we obtained scores reflecting participants' positive versus negative attachment-derived self- and other-models by means of the Relationship Questionnaire. We controlled for possible confounding factors by also obtaining scores reflecting internalizing/externalizing problems, schizotypy, and borderline symptomatology. Our results revealed that participants with a more negative attachment-derived self-model showed increased brain activity during positive and negative adjective evaluation regarding the self, but decreased brain activity during negative adjective evaluation regarding a close other, in bilateral amygdala/parahippocampus, bilateral anterior temporal pole/anterior superior temporal gyrus, and left dorsolateral prefrontal cortex. These findings suggest that a low positivity of the self-concept characteristic for the attachment anxiety dimension may influence neural information processing, but in opposite directions when it comes to self- versus (close) other-representations. We discuss our results in the framework of attachment theory and regarding their implications especially for adolescent social-emotional development and social integration
The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to
The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria
The antimalarial MMV688533 provides potential for single-dose cures with a high barrier to
The emergence and spread of Plasmodium falciparum resistance to first-line antimalarials creates an imperative to identify and develop potent preclinical candidates with distinct modes of action. Here, we report the identification of MMV688533, an acylguanidine that was developed following a whole-cell screen with compounds known to hit high-value targets in human cells. MMV688533 displays fast parasite clearance in vitro and is not cross-resistant with known antimalarials. In a P. falciparum NSG mouse model, MMV688533 displays a long-lasting pharmacokinetic profile and excellent safety. Selection studies reveal a low propensity for resistance, with modest loss of potency mediated by point mutations in PfACG1 and PfEHD. These proteins are implicated in intracellular trafficking, lipid utilization, and endocytosis, suggesting interference with these pathways as a potential mode of action. This preclinical candidate may offer the potential for a single low-dose cure for malaria
A metodologia de Lamarck
Neste artigo, o mĂ©todo cientĂfico de Jean-Baptiste Lamarck Ă© estudado sob o ponto de vista de seu discurso metodolĂłgico, bem como sob o ponto de vista de sua prĂĄtica cientĂfica. Essa metodologia Ă© comparada Ă preconizada por Condillac, assim como Ă dos "ideĂłlogos" (idĂ©ologues) grupo no qual se costuma incluir o prĂłprio Lamarck. Mostra-se que o discurso metodolĂłgico de Lamarck assemelha-se ao dos ideĂłlogos; no entanto, sua prĂĄtica cientĂfica nĂŁo se coaduna com esse enfoque. Em vez de seguir uma abordagem empirista, a obra de Lamarck se fundamenta em princĂpios metafĂsicos gerais sobre a natureza. Sob o ponto de vista dos ideĂłlogos, seu trabalho deveria ser rejeitado - o que de fato ocorreu - como um mero sistema (systĂšme) metafĂsico - no sentido pejorativo utilizado pelos seguidores de Condillac. No entanto, o presente artigo argumenta que esse Ă© justamente um importante e inovador aspecto da obra de Lamarck, que permitiu a eclosĂŁo do evolucionismo moderno
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