Search results for " Migration"
showing 10 items of 754 documents
Changes in the expression of cation-Cl- cotransporters, NKCC1 and KCC2, during cortical malformation induced by neonatal freeze-lesion.
2007
Focal cortical malformations comprise a heterogeneous group of disturbances in brain development, often associated with intractable epilepsy. A focal freeze-lesion of cerebral cortex in newborn rat produces a cortical malformation that resembles human polymicrogyria, clinical conditions that results from abnormal neuronal migration. The change in GABAergic functions that occurs during early brain development is induced by an alteration in Cl(-) homeostasis and plays important roles in neocortical development by modulating such events as laminar organization and synaptogenesis. We therefore investigated the relationship between pathogenesis of polymicrogyria and ontogeny of Cl(-) homeostasis…
Migration of Neuronal Precursors From the Telencephalic Ventricular Zone Into the Olfactory Bulb in Adult Zebrafish
2011
In the brain of adult mammals, neuronal precursors are generated in the subventricular zone in the lateral wall of the lateral ventricles and migrate into the olfactory bulbs (OBs) through a well-studied route called the rostral migratory stream (RMS). Recent studies have revealed that a comparable neural stem cell niche is widely conserved at the ventricular wall of adult vertebrates. However, little is known about the migration route of neuronal precursors in nonmammalian adult brains. Here, we show that, in the adult zebrafish, a cluster of neuronal precursors generated in the telencephalic ventricular zone migrates into the OB via a route equivalent to the mammalian RMS. Unlike the mamm…
Kinetics of echinostoma caproni (trematoda: echinostomatidae) antigens in feces and serum of experimentally infected hamsters and rats
2004
This study reports on the kinetics of antibody production to Echinostoma caproni and the dynamics of antigens in feces and sera in 2 experimental hosts (hamsters and rats) that display different degrees of susceptibility with this echinostome. Echinostoma caproniproduced chronic infections in hamsters, whereas rats lost the infection at 49-56 days postinfection (DPI). Hamsters developed higher antibody responses than rats, probably in relation to different intestinal absorptions of worm antigens in each host species. The levels of coproantigens were indicative of the course of infection in each host. Positive coproantigen levels were detected at 1-2 DPI in both hosts, and the values remaine…
Rapid change in host use of the common cuckoo Cuculus canorus linked to climate change
2010
Parasites require synchrony with their hosts so if host timing changes with climate change, some parasites may decline and eventually go extinct. Residents and short-distance migrant hosts of the brood parasitic common cuckoo, Cuculus canorus , have advanced their phenology in response to climate change more than long-distance migrants, including the cuckoo itself. Because different parts of Europe show different degrees of climate change, we predicted that use of residents or short-distance migrants as hosts should have declined in areas with greater increase in spring temperature. Comparing relative frequency of parasitism of the two host categories in 23 European countries before and af…
Estradiol induces endothelial cell migration and proliferation through estrogen receptor-enhanced RhoA/ROCK pathway
2010
Migration and proliferation of endothelial cells are involved in re-endothelialization and angiogenesis, two important cardiovascular processes that are increased in response to estrogens. RhoA, a small GTPase which controls multiple cellular processes, is involved in the control of cell migration and proliferation. Our aim was to study the role of RhoA on estradiol-induced migration and proliferation and its dependence on estrogen receptors activity. Human umbilical vein endothelial cells were stimulated with estradiol, in the presence or absence of ICI 182780 (estrogen receptors antagonist) and Y-27632 (Rho kinase inhibitor). Estradiol increased Rho GEF-1 gene expression and RhoA (gene an…
Macrophage inhibiting activity in serum and central lymph of Listeria-immune mice.
1975
Serum and central lymph from mice immunized with live Listeria monocytogenes six days previously and boostered four hours before collection exerted significant inhibition of macrophage migration in vitro. It is concluded that lymphokines or lymphokine-like products of the cellular immune reaction are released in vivo and are possibly instrumental in the generation of acquired cellular antibacterial immunity.
Subventricular zone localized irradiation affects the generation of proliferating neural precursor cells and the migration of neuroblasts
2012
Radiation therapy is a part of the standard treatment for brain tumor patients, often resulting in irreversible neuropsychological deficits. These deficits may be due to permanent damage to the neural stem cell (NSC) niche, damage to local neural progenitors, or neurotoxicity. Using a computed tomography-guided localized radiation technique, we studied the effects of radiation on NSC proliferation and neuroblast migration in the mouse brain. Localized irradiation of the subventricular zone (SVZ) eliminated the proliferating neural precursor cells and migrating neuroblasts. After irradiation, type B cells in the SVZ lacked the ability to generate migrating neuroblasts. Neuroblasts from the u…
Habitat-specific ranging patterns of Dian's tarsiers (Tarsius dianae) as revealed by radiotracking
2006
Dian's tarsier Tarsius dianae, one of the smallest primates on earth, is endemic to the central regions of Sulawesi, Indonesia. To evaluate the effects of increasing land use by humans on the ranging patterns of this nocturnal insect hunter, four study plots along a gradient of anthropogenic disturbance were selected for this study. In these plots, 71 tarsiers were captured with mist nets, and 30 of these were fitted with 3.9 g radiotransmitters and subsequently tracked over the course of 2 weeks per animal. The average home ranges were 1.1-1.8 ha in size, with the smallest ranges in slightly disturbed habitat and the largest ranges in a heavily disturbed plantation. These findings coincide…
The insectivorous batPipistrellus nathusiiuses a mixed-fuel strategy to power autumn migration
2012
In contrast to birds, bats are possibly limited in their capacity to use body fat as an energy source for long migrations. Here, we studied the fuel choice of migratoryPipistrellus nathusii(approximate weight: 8 g) by analysing the stable carbon isotope ratio (δ13CV-PDB) of breath and potential energy sources. Breathδ13CV-PDBwas intermediate betweenδ13CV-PDBof insect prey and adipocyte triacylglycerols, suggesting a mixed-fuel use ofP. nathusiiduring autumn migration. To clarify the origin of oxidized fatty acids, we performed feeding experiments with captiveP. nathusii. After an insect diet, bat breath was enriched in13C relative to the bulk and fat portion of insects, but not deviating fr…