Search results for "Bill"
showing 10 items of 116 documents
Carotenoid trade-off between parasitic resistance and sexual display: an experimental study in the blackbird (Turdus merula).
2008
Many parasites depress the expression of the carotenoid-based colour displays of their hosts, and it has been hypothesized that animals face a trade-off in carotenoid allocation between immune functions and ‘degree of ornamentation’. While numerous correlative studies suggest that parasite infection decreases the intensity of carotenoid-based colour displays, the existence of this trade-off has never been demonstrated experimentally in a host–parasite model. In this study, we used the blackbird ( Turdus merula ) and Isospora (an intestinal parasite) to assess whether this trade-off does indeed exist. Blackbirds were supplemented with carotenoids while simultaneously being exposed to parasi…
Epizootic of dolphin morbillivirus on the Catalonian Mediterranean coast in 2007
2011
BETWEEN 1990 and 1992, thousands of striped dolphins (Stenella coeruleoalba) stranded along the Mediterranean coast due to a newly described virus, the dolphin morbillivirus (DMV) (Domingo and others 1990, 1992). DMV is one of the several morbilliviruses that have killed marine mammals worldwide since 1987 (Di Guardo and others 2005). A new DMV epizootic has been recently confirmed from the Mediterranean Spanish and French coasts during 2007 to 2008 (Fernández and others 2008, Raga and others 2008, Keck and others 2010). This short communication describes the pathological findings associated with DMV infection and secondary infections, observed during this epizootic on the Mediterranean coa…
Dynamic in vivo Imaging of Microvasculature and Perfusion by Miniaturized Confocal Laser Microscopy
2008
<i>Introduction:</i> Microvasculature and associated pathologies mandate dynamic imaging. We evaluated a novel miniaturized confocal laser scanning probe for in vivo visualization of blood vessels, blood flow, cell tracking and perfusion in both healthy rodents and disease models.<i> Methods:</i> The hand-held confocal microscopy system allowed a 500- to 2,400-fold magnification at a dynamically variable imaging depth. Different intravital stains were used alone or in combination for tissue, nuclear, plasma and vascular endothelial cell staining and for blood flow visualization, and targeted staining for individual cell populations. <i>Results:</i> Precis…
A review of virus infections of cataceans and the potential impact of morbilliviruses, poxviruses and papillomaviruses on host population dynamics.
1999
Viruses belonging to 9 families have been detected in cetaceans. We critically review the clinical features, pathology and epidemiology of the diseases they cause. Cetacean morbillivirus (family Paramyxoviridae) induces a serious disease with a high mortality rate and persists in several populations. It may have long-term effects on the dynamics of cetacean populations either as enzootic infection or recurrent epizootics. The latter presumably have the more profound impact due to removal of sexually mature individuals. Members of the family Poxviridae infect several species of odontocetes, resulting in ring and tattoo skin lesions. Although poxviruses apparently do not induce a high mortali…
Microcirculatory alterations in a mongolian gerbil sinus-vein thrombosis model
2001
Summary Background and purpose. The pathophysiology of sinus-vein thrombosis (SVT) is still controversial in patients and experimental animals, the microcirculatory alterations in particular. This study was designed to develop a new sinus-vein thrombosis model and to further elucidate pathophysiological events such as the relationship between local and regional cerebral blood flow and haemoglobin oxygen saturation (HbSO2), changes of the microvasculature, leukocyte behaviour and brain tissue damage. Methods. In a first experimental series, animals were divided into two groups which resulted from different procedures of inducing SVT. In the SSS middle occlusion group (SMO group), SVT was ind…
Characterization of rodent pineal astrocytes by immunofluorescence microscopy using a monoclonal antibody (J1-31).
1987
In previous studies pineal astrocytes have been characterized immunohistochemically mainly by use of antisera to glial fibrillary acidic protein. Because of the recent demonstration of this protein in non-astrocytic cells the question of its specificity as an astrocytic marker has been raised. A possible alternative tool for characterizing pineal astrocytes is the J1-31 monoclonal antibody, which is directed against a 30 000 dalton astrocytic protein clearly distinguishable from glial fibrillary acidic protein. Immunofluorescence microscopy of this antibody in the pineal gland of rat and guinea-pig revealed a staining pattern similar to that obtained by glial acidic fibrillary protein antis…
Stimulation of Serotonin-N-Acetyltransferase Activity in the Pineal Gland of the Mongolian Gerbil (Meriones unguiculatus) by Intracerebroventricular …
1989
There is ever-increasing evidence that intrapineal peptides have an important role in the modulation of pineal melatonin synthesis. In the pineal gland of the Mongolian gerbil (Meriones unguiculatus), we have previously shown the presence of VIP-immunoreactive nerve fibers as well as pinealocytic VIP receptors. To assess the functional significance of these findings, 10 microliters of a 1 microM or 1 nM solution of VIP were injected into the lateral ventricle of gerbils over a period of 10 min. Animals were killed 1.5 hr after injection, and the superficial pineal glands were excised and assayed for N-acetyltransferase (NAT) activity. Injection of the 1 microM VIP solution stimulated the NA…
Comparative investigations on the actions of ACTH1-24, somatostatin, neurotensin, substance P and vasopressin on locus coeruleus neuronal activity in…
1987
A considerable number of neuropeptides have been localized immunohistochemically in the area of the locus coeruleus of the rat. The objective of this study was to assess the actions of some of these transmitter candidates on spontaneously active locus coeruleus neurons in vitro. The effects of bath-applied peptides on the discharge rate of individual locus coeruleus neurons were investigated. A midpontine slice preparation of the gerbil brain was used. Excitatory dose-dependent effects were found with four peptides with the following rank order of potency: Substance P, (Arg8)-vasopressin, neurotensin, ACTH1–24. Somatostatin hyperpolarized all neurons tested. Given the pronounced effects see…
Short-term ischemia usually used for ischemic preconditioning causes loss of dendritic integrity after long-term survival in the gerbil hippocampus
2006
Ischemic preconditioning has been established as a powerful experimental neuroprotective strategy, both after global and focal cerebral ischemia. Little is known, however, about the structural and functional long-term outcome. Therefore, our present study was designed to check for potential subtle alterations in the hippocampus after long-term survival. Gerbils were subjected either to short-term ischemia of 2.5 min duration usually used for ischemic preconditioning (n=8) or to sham operation (n=6) and allowed to survive for 6 weeks. Hippocampi with neuronal densities comparable to those of sham-operated control animals were analyzed for dendritic marker proteins MAP2, MAP1B and synaptopodi…
Capillary flow and diameter changes during reperfusion after global cerebral ischemia studied by intravital video microscopy.
2004
The reaction of cerebral capillaries to ischemia is unclear. Based on Hossmann's observation of postischemic “delayed hypoperfusion,” we hypothesized that capillary flow is decreased during reperfusion because of increased precapillary flow resistance. To test this hypothesis, we measured cerebral capillary erythrocyte velocity and diameter changes by intravital microscopy in gerbils. A cranial window was prepared over the frontoparietal cortex in 26 gerbils anesthetized with halothane. The animals underwent either a sham operation or fifteen minutes of bilateral carotid artery occlusion causing global cerebral ischemia. Capillary flow velocities were measured by frame-to-frame tracking of…