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Find video protocols related to scientific articles indexed in Pubmed.
Diffusion tensor imaging differentiates vascular parkinsonism from parkinsonian syndromes of degenerative origin in elderly subjects.
Eur J Radiol
PUBLISHED: 07-24-2014
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The etiologic diagnosis of parkinsonian syndromes is of particular importance when considering syndromes of vascular or degenerative origin. The purpose of this study is to find differences in the white-matter architecture between those two groups in elderly patients.
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Hyperdominance in the Amazonian tree flora.
Hans ter Steege, Nigel C A Pitman, Daniel Sabatier, Christopher Baraloto, Rafael P Salomão, Juan Ernesto Guevara, Oliver L Phillips, Carolina V Castilho, William E Magnusson, Jean-François Molino, Abel Monteagudo, Percy Núñez Vargas, Juan Carlos Montero, Ted R Feldpausch, Eurídice N Honorio Coronado, Tim J Killeen, Bonifacio Mostacedo, Rodolfo Vásquez, Rafael L Assis, John Terborgh, Florian Wittmann, Ana Andrade, William F Laurance, Susan G W Laurance, Beatriz S Marimon, Ben-Hur Marimon, Ima Célia Guimarães Vieira, Iêda Leão Amaral, Roel Brienen, Hernán Castellanos, Dairon Cárdenas López, Joost F Duivenvoorden, Hugo F Mogollón, Francisca Dionizia de Almeida Matos, Nállarett Dávila, Roosevelt García-Villacorta, Pablo Roberto Stevenson Diaz, Flavia Costa, Thaise Emilio, Carolina Levis, Juliana Schietti, Priscila Souza, Alfonso Alonso, Francisco Dallmeier, Alvaro Javier Duque Montoya, Maria Teresa Fernandez Piedade, Alejandro Araujo-Murakami, Luzmila Arroyo, Rogério Gribel, Paul V A Fine, Carlos A Peres, Marisol Toledo, Gerardo A Aymard C, Tim R Baker, Carlos Cerón, Julien Engel, Terry W Henkel, Paul Maas, Pascal Pétronelli, Juliana Stropp, Charles Eugene Zartman, Doug Daly, David Neill, Marcos Silveira, Marcos Ríos Paredes, Jérôme Chave, Diógenes de Andrade Lima Filho, Peter Møller Jørgensen, Alfredo Fuentes, Jochen Schöngart, Fernando Cornejo Valverde, Anthony Di Fiore, Eliana M Jimenez, Maria Cristina Peñuela Mora, Juan Fernando Phillips, Gonzalo Rivas, Tinde R van Andel, Patricio von Hildebrand, Bruce Hoffman, Eglée L Zent, Yadvinder Malhi, Adriana Prieto, Agustín Rudas, Ademir R Ruschell, Natalino Silva, Vincent Vos, Stanford Zent, Alexandre A Oliveira, Angela Cano Schutz, Therany Gonzales, Marcelo Trindade Nascimento, Hirma Ramirez-Angulo, Rodrigo Sierra, Milton Tirado, María Natalia Umaña Medina, Geertje van der Heijden, César I A Vela, Emilio Vilanova Torre, Corine Vriesendorp, Ophelia Wang, Kenneth R Young, Claudia Baider, Henrik Balslev, Cid Ferreira, Italo Mesones, Armando Torres-Lezama, Ligia Estela Urrego Giraldo, Roderick Zagt, Miguel N Alexiades, Lionel Hernandez, Isau Huamantupa-Chuquimaco, William Milliken, Walter Palacios Cuenca, Daniela Pauletto, Elvis Valderrama Sandoval, Luis Valenzuela Gamarra, Kyle G Dexter, Ken Feeley, Gabriela Lopez-Gonzalez, Miles R Silman.
Science
PUBLISHED: 10-19-2013
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The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the worlds most diverse tree community.
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Rapid sensing of circulating ghrelin by hypothalamic appetite-modifying neurons.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 01-07-2013
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To maintain homeostasis, hypothalamic neurons in the arcuate nucleus must dynamically sense and integrate a multitude of peripheral signals. Blood-borne molecules must therefore be able to circumvent the tightly sealed vasculature of the blood-brain barrier to rapidly access their target neurons. However, how information encoded by circulating appetite-modifying hormones is conveyed to central hypothalamic neurons remains largely unexplored. Using in vivo multiphoton microscopy together with fluorescently labeled ligands, we demonstrate that circulating ghrelin, a versatile regulator of energy expenditure and feeding behavior, rapidly binds neurons in the vicinity of fenestrated capillaries, and that the number of labeled cell bodies varies with feeding status. Thus, by virtue of its vascular connections, the hypothalamus is able to directly sense peripheral signals, modifying energy status accordingly.
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Pituitary growth hormone network responses are sexually dimorphic and regulated by gonadal steroids in adulthood.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 11-22-2010
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There are well-recognized sex differences in many pituitary endocrine axes, usually thought to be generated by gonadal steroid imprinting of the neuroendocrine hypothalamus. However, the recognition that growth hormone (GH) cells are arranged in functionally organized networks raises the possibility that the responses of the network are different in males and females. We studied this by directly monitoring the calcium responses to an identical GH-releasing hormone (GHRH) stimulus in populations of individual GH cells in slices taken from male and female murine GH-eGFP pituitary glands. We found that the GH cell network responses are sexually dimorphic, with a higher proportion of responding cells in males than in females, correlated with greater GH release from male slices. Repetitive waves of calcium spiking activity were triggered by GHRH in some males, but were never observed in females. This was not due to a permanent difference in the network architecture between male and female mice; rather, the sex difference in the proportions of GH cells responding to GHRH were switched by postpubertal gonadectomy and reversed with hormone replacements, suggesting that the network responses are dynamically regulated in adulthood by gonadal steroids. Thus, the pituitary gland contributes to the sexually dimorphic patterns of GH secretion that play an important role in differences in growth and metabolism between the sexes.
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The comparison between circadian oscillators in mouse liver and pituitary gland reveals different integration of feeding and light schedules.
PLoS ONE
PUBLISHED: 08-04-2010
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The mammalian circadian system is composed of multiple peripheral clocks that are synchronized by a central pacemaker in the suprachiasmatic nuclei of the hypothalamus. This system keeps track of the external world rhythms through entrainment by various time cues, such as the light-dark cycle and the feeding schedule. Alterations of photoperiod and meal time modulate the phase coupling between central and peripheral oscillators. In this study, we used real-time quantitative PCR to assess circadian clock gene expression in the liver and pituitary gland from mice raised under various photoperiods, or under a temporal restricted feeding protocol. Our results revealed unexpected differences between both organs. Whereas the liver oscillator always tracked meal time, the pituitary circadian clockwork showed an intermediate response, in between entrainment by the light regimen and the feeding-fasting rhythm. The same composite response was also observed in the pituitary gland from adrenalectomized mice under daytime restricted feeding, suggesting that circulating glucocorticoids do not inhibit full entrainment of the pituitary clockwork by meal time. Altogether our results reveal further aspects in the complexity of phase entrainment in the circadian system, and suggest that the pituitary may host oscillators able to integrate multiple time cues.
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Cellular in vivo imaging reveals coordinated regulation of pituitary microcirculation and GH cell network function.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 02-16-2010
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Growth hormone (GH) exerts its actions via coordinated pulsatile secretion from a GH cell network into the bloodstream. Practically nothing is known about how the network receives its inputs in vivo and releases hormones into pituitary capillaries to shape GH pulses. Here we have developed in vivo approaches to measure local blood flow, oxygen partial pressure, and cell activity at single-cell resolution in mouse pituitary glands in situ. When secretagogue (GHRH) distribution was modeled with fluorescent markers injected into either the bloodstream or the nearby intercapillary space, a restricted distribution gradient evolved within the pituitary parenchyma. Injection of GHRH led to stimulation of both GH cell network activities and GH secretion, which was temporally associated with increases in blood flow rates and oxygen supply by capillaries, as well as oxygen consumption. Moreover, we observed a time-limiting step for hormone output at the perivascular level; macromolecules injected into the extracellular parenchyma moved rapidly to the perivascular space, but were then cleared more slowly in a size-dependent manner into capillary blood. Our findings suggest that GH pulse generation is not simply a GH cell network response, but is shaped by a tissue microenvironment context involving a functional association between the GH cell network activity and fluid microcirculation.
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Ghrelin stimulation of growth hormone-releasing hormone neurons is direct in the arcuate nucleus.
PLoS ONE
PUBLISHED: 01-08-2010
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Ghrelin targets the arcuate nucleus, from where growth hormone releasing hormone (GHRH) neurones trigger GH secretion. This hypothalamic nucleus also contains neuropeptide Y (NPY) neurons which play a master role in the effect of ghrelin on feeding. Interestingly, connections between NPY and GHRH neurons have been reported, leading to the hypothesis that the GH axis and the feeding circuits might be co-regulated by ghrelin.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.