Search results for "Brief Communication"
showing 10 items of 24 documents
Context specificity of both acquisition and extinction of a Pavlovian conditioned response
2016
It is widely held that the extinction of a conditioned response is more context specific than its initial acquisition. One proposed explanation is that context serves to disambiguate the meaning of a stimulus. Using a procedure that equated the learning histories of the contexts, we show that the memory of an appetitive Pavlovian association can be highly context specific despite being unambiguous. This result is inconsistent with predictions of the Rescorla–Wagner model of learning but in line with configural accounts of contextual control of behavior. We propose an explanatory model in which context serves to modulate the gain of associative strength and which expands upon the configural …
Defective insulin secretory response to intravenous glucose in C57Bl/6J compared to C57Bl/6N mice
2014
Objective: The C57Bl/6J (Bl/6J) mouse is the most widely used strain in metabolic research. This strain carries a mutation in nicotinamide nucleotide transhydrogenase (Nnt), a mitochondrial enzyme involved in NADPH production, which has been suggested to lead to glucose intolerance and beta-cell dysfunction. However, recent reports comparing Bl/6J to Bl/6N (carrying the wild-type Nnt allele) under normal diet have led to conflicting results using glucose tolerance tests. Thus, we assessed glucose-stimulated insulin secretion (GSIS), insulin sensitivity, clearance and central glucose-induced insulin secretion in Bl/6J and N mice using gold-standard methodologies. Methods: GSIS was measured u…
Intestinal symptoms and Blastocystis load in schoolchildren of Paranaguá Bay, Paraná, Brazil
2017
ABSTRACT The symptomatology of Blastocystis cannot be attributed to any particular subtype, although can be related to a high Blastocystis infection load. One stool sample from each of 217 schoolchildren of Vale de Sol Paranaguá Bay (Paraná, Brazil) was collected. Three milliliters of each fixed stool sample were processed applying the formalin-ether concentration technique. After obtaining the overall prevalence of intestinal parasites, quantification was carried out in Blastocystis positive samples. A total of 75/217 (34.6%) children suffered from intestinal symptoms (abdominal pain and/or persistent diarrhea), of whom 41.3% (31/75) presented moderate/heavy Blastocystis load with a statis…
A Pathway in the Brainstem for Roll-Tilt of the Subjective Visual Vertical: Evidence from a Lesion–Behavior Mapping Study
2012
The perceived subjective visual vertical (SVV) is an important sign of a vestibular otolith tone imbalance in the roll plane. Previous studies suggested that unilateral pontomedullary brainstem lesions cause ipsiversive roll-tilt of SVV, whereas pontomesencephalic lesions cause contraversive roll-tilts of SVV. However, previous data were of limited quality and lacked a statistical approach. We therefore tested roll-tilt of the SVV in 79 human patients with acute unilateral brainstem lesions due to stroke by applying modern statistical lesion–behavior mapping analysis. Roll-tilt of the SVV was verified to be a brainstem sign, and for the first time it was confirmed statistically that lesions…
The visual orientation memory of Drosophila requires Foraging (PKG) upstream of Ignorant (RSK2) in ring neurons of the central complex
2012
Orientation and navigation in a complex environment requires path planning and recall to exert goal-driven behavior. Walking Drosophila flies possess a visual orientation memory for attractive targets which is localized in the central complex of the adult brain. Here we show that this type of working memory requires the cGMP-dependent protein kinase encoded by the foraging gene in just one type of ellipsoid-body ring neurons. Moreover, genetic and epistatic interaction studies provide evidence that Foraging functions upstream of the Ignorant Ribosomal-S6 Kinase 2, thus revealing a novel neuronal signaling pathway necessary for this type of memory in Drosophila.
Toxoplasma gondii seroprevalence in extensively farmed wild boars (Sus scrofa) in Denmark
2019
Toxoplasma gondii is a zoonotic parasite of worldwide importance. In this study, we estimated T. gondii seroprevalence in extensively farmed wild boars in Denmark, where little is known about T. gondii in animal hosts. Our study focused on wild boars because they are considered good indicator species for the presence of T. gondii, and wild boar meat is used for human consumption. Serum samples from 101 wild boars collected in 2016-2018 from five different locations from the continental part of Denmark, Jutland, were screened for anti-T. gondii antibodies. The samples were analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA). Samples from 28 (27.7%) of the 101 wild …
Haemodynamic predictors of a penetrating atherosclerotic ulcer rupture using fluid-structure interaction analysis
2013
We present preliminary data on the flow-induced haemodynamic and structural loads exerted on a penetrating atherosclerotic aortic ulcer (PAU). Specifically, one-way fluid-structure interaction analysis was performed on the aortic model reconstructed from a 66-year-old male patient with a PAU that evolved into an intramural haematoma and rupture of the thoracic aorta. The results show that elevated blood pressure (117 mmHg) and low flow velocity at the aortic wall (0.15 m/s(2)) occurred in the region of the PAU. We also found a low value of time-averaged wall shear stress (1.24 N/m(2)) and a high value of the temporal oscillation in the wall shear stress (oscillatory shear index = 0.13) in t…
Beta-amyloid monomers are neuroprotective
2009
The 42-aa-long β-amyloid protein—Aβ1-42—is thought to play a central role in the pathogenesis of Alzheimer's disease (AD) (Walsh and Selkoe, 2007). Data from AD brain (Shankar et al., 2008), transgenic APP (amyloid precursor protein)-overexpressing mice (Lesné et al., 2006), and neuronal cultures treated with synthetic Aβ peptides (Lambert et al., 1998) indicate that self-association of Aβ1-42monomers into soluble oligomers is required for neurotoxicity. The function of monomeric Aβ1-42is unknown. The evidence that Aβ1-42is present in the brain and CSF of normal individuals suggests that the peptide is physiologically active (Shoji, 2002). Here we show that synthetic Aβ1-42monomers support …
Progression-free survival as a surrogate for overall survival in advanced/recurrent gastric cancer trials: a meta-analysis.
2013
The traditional endpoint for assessing efficacy of chemotherapies for advanced/recurrent gastric cancer is overall survival (OS), but OS requires prolonged follow-up. We investigated whether progression-free survival (PFS) is a valid surrogate for OS. Using individual patient data from the GASTRIC meta-analysis, surrogacy of PFS was assessed through the correlation between the endpoints and through the correlation between the treatment effects on the endpoints. External validation of the prediction based on PFS was also evaluated. Individual data from 4069 patients in 20 randomized trials were analyzed. The rank correlation coefficient between PFS and OS was 0.853 (95% confidence interval […
Subtle retinal pathology in amyotrophic lateral sclerosis
2014
Amyotrophic lateral sclerosis (ALS) is characterized by neuro-ophthalmological abnormalities beyond disturbed oculomotor control such as decreased visual acuity and disturbed visual evoked potentials. Here we report retinal alterations in a cohort of 24 patients with clinically definite (n = 20) or probable (n = 4) ALS as compared to matched controls. High-resolution spectral domain optical coherence tomography with retinal segmentation revealed a subtle reduction in the macular thickness and the retinal nerve fiber layer (RNFL) as well as a marked thinning of the inner nuclear layer (INL). Our data indicate an unprecedented retinal damage pattern and suggest neurodegeneration beyond the mo…