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  1 / 4053 MEDLINE  
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PMID:28877194
Autor:Bigelow J; Malone BJ
Endereço:Coleman Memorial Laboratory, University of California, San Francisco, California, United States of America.
Título:Cluster-based analysis improves predictive validity of spike-triggered receptive field estimates.
Fonte:PLoS One; 12(9):e0183914, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Spectrotemporal receptive field (STRF) characterization is a central goal of auditory physiology. STRFs are often approximated by the spike-triggered average (STA), which reflects the average stimulus preceding a spike. In many cases, the raw STA is subjected to a threshold defined by gain values expected by chance. However, such correction methods have not been universally adopted, and the consequences of specific gain-thresholding approaches have not been investigated systematically. Here, we evaluate two classes of statistical correction techniques, using the resulting STRF estimates to predict responses to a novel validation stimulus. The first, more traditional technique eliminated STRF pixels (time-frequency bins) with gain values expected by chance. This correction method yielded significant increases in prediction accuracy, including when the threshold setting was optimized for each unit. The second technique was a two-step thresholding procedure wherein clusters of contiguous pixels surviving an initial gain threshold were then subjected to a cluster mass threshold based on summed pixel values. This approach significantly improved upon even the best gain-thresholding techniques. Additional analyses suggested that allowing threshold settings to vary independently for excitatory and inhibitory subfields of the STRF resulted in only marginal additional gains, at best. In summary, augmenting reverse correlation techniques with principled statistical correction choices increased prediction accuracy by over 80% for multi-unit STRFs and by over 40% for single-unit STRFs, furthering the interpretational relevance of the recovered spectrotemporal filters for auditory systems analysis.
Tipo de publicação: JOURNAL ARTICLE


  2 / 4053 MEDLINE  
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PMID:28331086
Autor:Delpeut S; Sawatsky B; Wong XX; Frenzke M; Cattaneo R; von Messling V
Endereço:INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada.
Título:Nectin-4 Interactions Govern Measles Virus Virulence in a New Model of Pathogenesis, the Squirrel Monkey (Saimiri sciureus).
Fonte:J Virol; 91(11), 2017 Jun 01.
ISSN:1098-5514
País de publicação:United States
Idioma:eng
Resumo:In addition to humans, only certain nonhuman primates are naturally susceptible to measles virus (MeV) infection. Disease severity is species dependent, ranging from mild to moderate for macaques to severe and even lethal for certain New World monkey species. To investigate if squirrel monkeys ( ), which are reported to develop a course of disease similar to humans, may be better suited than macaques for the identification of virulence determinants or the evaluation of therapeutics, we infected them with a green fluorescent protein-expressing MeV. Compared to cynomolgus macaques ( ) infected with the same virus, the squirrel monkeys developed more-severe immunosuppression, higher viral load, and a broader range of clinical signs typical for measles. In contrast, infection with an MeV unable to interact with the epithelial receptor nectin-4, while causing immunosuppression, resulted in only a mild and transient rash and a short-lived elevation of the body temperature. Similar titers of the wild-type and nectin-4-blind MeV were detected in peripheral blood mononuclear cells and lymph node homogenates, but only the wild-type virus was found in tracheal lavage fluids and urine. Thus, our study demonstrates the importance of MeV interactions with nectin-4 for clinical disease in the new and better-performing model of measles pathogenesis. The characterization of mechanisms underlying measles virus clinical disease has been hampered by the lack of an animal model that reproduces the course of disease seen in human patients. Here, we report that infection of squirrel monkeys ( ) fulfills these requirements. Comparative infection with wild-type and epithelial cell receptor-blind viruses demonstrated the importance of epithelial cell infection for clinical disease, highlighting the spread to epithelia as an attractive target for therapeutic strategies.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Cell Adhesion Molecules); 0 (Nectins); 147336-22-9 (Green Fluorescent Proteins)


  3 / 4053 MEDLINE  
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PMID:28165629
Autor:Lins E Lins FL; Mayor P; Silva Filho E; Imbeloni AA; Bandeira da Silva W; Monteiro MV; Nunes-Pinheiro DC; Monteiro FO
Endereço:Postgraduate Program in Heath and Animal Production on the Amazon (PPGSPAA), Federal Rural University of the Amazon (UFRA), Belem, Brazil.
Título:Renal biochemistry variables and ultrasonographic imaging in healthy Squirrel monkeys (Saimiri collinsi).
Fonte:Vet Clin Pathol; 46(1):126-131, 2017 Mar.
ISSN:1939-165X
País de publicação:United States
Idioma:eng
Resumo:BACKGROUND: The combined use of renal biochemistry and ultrasonographic imaging may improve the correct management of renal disease. Although renal disease is frequently observed in nonhuman primates, renal function markers have not yet been studied in Squirrel monkeys (Saimiri collinsi). OBJECTIVES: The aim of this study was to establish normal renal biochemistry variables and ultrasonographic features in Squirrel monkeys. MATERIAL AND METHODS: Renal biochemistry variables and ultrasonographic images were documented in 29 healthy Squirrel monkeys (15 males and 14 females). Urea, serum creatinine (SCr), and uric acid (UA) concentrations were measured by kinetic assay. Cystatin C (CysC) was analyzed by immunonephelometry. A multiple frequency linear array probe (5-12 MHz) was used for ultrasonographic imaging. The studied indicators of renal function were related to sex, age, and body mass. RESULTS: Serum creatinine was influenced by sex and body mass. Serum concentration of urea, UA, and CysC were not influenced by sex, age, and body mass. Ultrasonographic images provided accurate and comprehensive data for making clinical decisions for Squirrel monkeys. The total renal volume was only influenced by the body mass nested in sex and was positively correlated to body mass. Right renal volume was bigger than the left one. CONCLUSION: Normative standards for the renal evaluation, including biochemistry and ultrasonography, in the Squirrel monkey have been established correlated to age, sex, and body mass.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Biomarkers); 0 (Cystatin C)


  4 / 4053 MEDLINE  
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PMID:28150428
Autor:Polgár Z; Wood L; Haskell MJ
Endereço:Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre, Easter Bush, Scotland, UK.
Título:Individual differences in zoo-housed squirrel monkeys' (Saimiri sciureus) reactions to visitors, research participation, and personality ratings.
Fonte:Am J Primatol; 79(5), 2017 May.
ISSN:1098-2345
País de publicação:United States
Idioma:eng
Resumo:Understanding individual differences in captive squirrel monkeys is a topic of importance both for improving welfare by catering to individual needs, and for better understanding the results and implications of behavioral research. In this study, 23 squirrel monkeys (Saimiri sciureus), housed in an environment that is both a zoo enclosure and research facility, were assessed for (i) the time they spent by an observation window under three visitor conditions: no visitors, small groups, and large groups; (ii) their likelihood of participating in voluntary research; and (iii) zookeepers, ratings of personality. A Friedman's ANOVA and Wilcoxon post-hoc tests comparing mean times found that the monkeys spent more time by the window when there were large groups present than when there were small groups or no visitors. Thus, visitors do not seem to have a negative effect and may be enriching for certain individuals. Through GLMM and correlational analyses, it was found that high scores on the personality trait of playfulness and low scores on cautiousness, depression, and solitude were significant predictors of increased window approach behavior when visitors were present. The GLMM and correlational analyses assessing the links between personality traits and research participation found that low scores of cautiousness and high scores of playfulness, gentleness, affection, and friendliness, were significant predictors. The implications of these results are discussed in relation to selection bias and its potential confounding effect on cognitive studies with voluntary participation.
Tipo de publicação: JOURNAL ARTICLE


  5 / 4053 MEDLINE  
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PMID:28088929
Autor:Sampaio WV; Oliveira KG; Leão DL; Caldas-Bussiere MC; Queiroz HL; Paim FP; Santos RR; Domingues SFS
Endereço:Laboratory of Wild Animal Biology and Medicine,Faculty of Veterinary Medicine,Federal University of Pará,Castanhal,Pará,Brazil.
Título:Morphologic analysis of sperm from two neotropical primate species: comparisons between the squirrel monkeys Saimiri collinsi and Saimiri vanzolinii.
Fonte:Zygote; 25(2):141-148, 2017 Apr.
ISSN:1469-8730
País de publicação:England
Idioma:eng
Resumo:Sperm morphometry can be applied to identify different animal groups and species and to evaluate sperm quality. Furthermore, knowledge on species-specific differences will help to enhance biological information, as well as to develop efficient reproductive technologies. The aims in the present study were to describe sperm morphometry from the recently characterized species S. collinsi and S. vanzolinii, to verify if the morphometric sperm patterns are similar or different between both species, and to determine if the sperm morphometry is affected by the levels of sperm defects using the S. collinsi as a model. Semen was collected from S. collinsi (n = 10) and S. vanzolinii (n = 2) monkeys, and sperm was submitted to morphological analysis. From the 10 samples from S. collinsi, five presented sperm of poor quality and two subgroups were formed for this species, i.e. high and poor quality sperm. Data on sperm motility and vigour were analysed, as well morphometric parameters on sperm head and tail. It was observed the normal morphometry was correlated with high quality sperm. Poor quality sperm presented smaller and 7% more ellipticity in their head, when compared with high quality sperm. Sperm from S. vanzolinii presented larger head than those from S. collinsi, but tail lengths were similar. Sperm morphometry can be used as a complementary tool to predict sperm motility and vigour for the S. collinsi species, and S. collinsi appear as a suitable model for S. vanzolinii.
Tipo de publicação: JOURNAL ARTICLE


  6 / 4053 MEDLINE  
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PMID:27587226
Autor:Schilling K; Gao Y; Stepniewska I; Choe AS; Landman BA; Anderson AW
Endereço:Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA. Electronic address: kurt.g.schilling@vanderbilt.edu.
Título:Reproducibility and variation of diffusion measures in the squirrel monkey brain, in vivo and ex vivo.
Fonte:Magn Reson Imaging; 35:29-38, 2017 Jan.
ISSN:1873-5894
País de publicação:Netherlands
Idioma:eng
Resumo:PURPOSE: Animal models are needed to better understand the relationship between diffusion MRI (dMRI) and the underlying tissue microstructure. One promising model for validation studies is the common squirrel monkey, Saimiri sciureus. This study aims to determine (1) the reproducibility of in vivo diffusion measures both within and between subjects; (2) the agreement between in vivo and ex vivo data acquired from the same specimen and (3) normal diffusion values and their variation across brain regions. METHODS: Data were acquired from three healthy squirrel monkeys, each imaged twice in vivo and once ex vivo. Reproducibility of fractional anisotropy (FA), mean diffusivity (MD), and principal eigenvector (PEV) was assessed, and normal values were determined both in vivo and ex vivo. RESULTS: The calculated coefficients of variation (CVs) for both intra-subject and inter-subject MD were below 10% (low variability) while FA had a wider range of CVs, 2-14% intra-subject (moderate variability), and 3-31% inter-subject (high variability). MD in ex vivo tissue was lower than in vivo (30%-50% decrease), while FA values increased in all regions (30-39% increase). The mode of angular differences between in vivo and ex vivo PEVs was 12 degrees. CONCLUSION: This study characterizes the diffusion properties of the squirrel monkey brain and serves as the groundwork for using the squirrel monkey, both in vivo and ex vivo, as a model for diffusion MRI studies.
Tipo de publicação: JOURNAL ARTICLE


  7 / 4053 MEDLINE  
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PMID:27574183
Autor:Lopes GP; Brito AB; Paim FP; Santos RR; Queiroz HL; Domingues SF
Endereço:Postgraduate Program in Animal Science, Federal University of Pará, Belém, Pará, Brazil.
Título:Comparative Characterization of the External Genitalia and Reproductive Tubular Organs of Three Species of the Genus Saimiri Voigt, 1831 (Primates: Cebidae).
Fonte:Anat Histol Embryol; 46(2):143-161, 2017 Apr.
ISSN:1439-0264
País de publicação:Germany
Idioma:eng
Resumo:Morphological information on the reproductive system allows the understanding of ecological and behavioural aspects of different species as well as supports the development of conservational strategies. Unfortunately, for many species, not enough relevant and precise information is available. In the present study, we describe for the first time the macroscopic and histological aspects of female genital organs and external female genitalia of Saimiri macrodon, Saimiri cassiquiarensis and Saimiri vanzolinii. We perform a comparison between these three peripatric species and investigate the possibility of their reproductive morphology to act as a factor of reproductive isolation. We have found that these species share many similarities in most of the analysed organs. Although some important differences were identified that may play an important role in the evolution of the components of the reproductive system of these species, those differences are not enough to compose a mechanism of reproductive isolation for these three species of Saimiri. The results of this study may be used to support the development of biotechnological approaches of reproduction and strategies for conservation programmes and management of threatened species of this genus, particularly S. vanzolinii, considered to be a vulnerable species to extinction.
Tipo de publicação: JOURNAL ARTICLE


  8 / 4053 MEDLINE  
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PMID:26897373
Autor:Duque-Díaz E; Díaz-Cabiale Z; Narváez JA; Coveñas R
Endereço:Laboratory of Neurosciences (Bloque Arhuaco), School of Medicine, Universidad de Santander UDES, Calle 70 n° 55-210, Campus Lago del Cacique, Bucaramanga, Colombia. duquee@usal.es.
Título:Mapping of enkephalins and adrenocorticotropic hormone in the squirrel monkey brainstem.
Fonte:Anat Sci Int; 92(2):275-292, 2017 Mar.
ISSN:1447-073X
País de publicação:Japan
Idioma:eng
Resumo:An immunocytochemical technique has been used to study for the first time the distribution of fibers and cell bodies containing leucine-enkephalin (leu-enk), methionine-enkephalin (met-enk) or adrenocorticotropic hormone (ACTH) in the whole brainstem of the squirrel monkey Saimiri sciureus. Cell bodies containing leu-enk or met-enk were found in the superior colliculus and the formatio reticularis tegmenti mesencephali, respectively. No immunoreactive cell bodies containing ACTH were observed. Leu-enk-immunoreactive fibers were observed in 40 brainstem nuclei/tracts/regions, fibers containing met-enk were found in 38 brainstem nuclei/tracts/regions and fibers containing ACTH were found in 26 nuclei/tracts/regions. In the latter case, the density of immunoreactive fibers was always low. A high/moderate density of leu-enk- or met-enk-immunoreactive fibers were found in 18 and 16 brainstem nuclei/tracts/regions, respectively. The distribution of immunoreactive fibers containing leu-enk or met-enk was quite similar, with both leu-enk and met-enk observed in 82.5 % of the squirrel monkey brainstem nuclei/tracts/regions. This relationship is less marked for met-enk and ACTH (60.5 %) and even lower for leu-enk and ACTH (52.5 %). In 42.5 % of the nuclei/tracts/regions of the squirrel monkey brainstem (colliculus superior, substantia grisea centralis, nucleus interpeduncularis, nucleus tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus parabrachialis, formatio reticularis, substantia nigra), we observed fibers containing all three neuropeptides. The widespread distribution reported here suggests that enkephalins and ACTH can be involved in several physiological functions. The distribution of the immunoreactive fibers reported here is quite similar to that previously reported for enkephalins and ACTH in Macaca species and humans.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Enkephalins); 9002-60-2 (Adrenocorticotropic Hormone)


  9 / 4053 MEDLINE  
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PMID:28032008
Autor:Wu TL; Mishra A; Wang F; Yang PF; Gore JC; Chen LM
Endereço:Vanderbilt University Institute of Imaging ScienceNashvilleTNUSA; Biomedical EngineeringVanderbilt UniversityNashvilleTNUSA.
Título:Effects of isoflurane anesthesia on resting-state fMRI signals and functional connectivity within primary somatosensory cortex of monkeys.
Fonte:Brain Behav; 6(12):e00591, 2016 Dec.
ISSN:2162-3279
País de publicação:United States
Idioma:eng
Resumo:INTRODUCTION: Correlated low-frequency fluctuations of resting-state functional magnetic resonance imaging (rsfMRI) signals have been widely used for inferring intrinsic brain functional connectivity (FC). In animal studies, accurate estimate of anesthetic effects on rsfMRI signals is demanded for reliable interpretations of FC changes. We have previously shown that inter-regional FC can reliably delineate local millimeter-scale circuits within digit representations of primary somatosensory cortex (S1) subregions (areas 3a, 3b, and 1) in monkeys under isoflurane anesthesia. The goals of this study are to determine (1) the general effects of isoflurane on rsfMRI signals in the S1 circuit and (2) whether the effects are functional- and regional- dependent, by quantifying the relationships between isoflurane levels, power and inter-regional correlation coefficients in digit and face regions of distinct S1 subregions. METHODS: Functional MRI data were collected from male adult squirrel monkeys at three different isoflurane levels (1.25%, 0.875%, and 0.5%). All scans were acquired on a 9.4T magnet with a 3-cm-diameter surface transmit-receive coil centered over the S1 cortex. Power and seed-based inter-regional functional connectivity analyses were subsequently performed. RESULTS: As anesthesia level increased, we observed (1) diminishing amplitudes of signal fluctuations, (2) reduced power of fluctuations in the low-frequency band used for connectivity measurements, (3) decreased inter-voxel connectivity around seed regions, and (4) weakened inter-regional FC across all pairs of regions of interest (digit-to-digit). The low-frequency power measures derived from rsfMRI signals from control muscle regions, however, did not exhibit any isoflurane level-related changes. Within the isoflurane dosage range we tested, the inter-regional functional connectivity differences were still detectable, and the effects of isoflurane did not differ across region-of-interest (ROI) pairs. CONCLUSION: Our data demonstrate that isoflurane induced similar dose-dependent suppressive effects on the power of rsfMRI signals and local fine-scale FC across functionally related but distinct S1 subregions.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Anesthetics, Inhalation); CYS9AKD70P (Isoflurane); S88TT14065 (Oxygen)


  10 / 4053 MEDLINE  
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PMID:27699211
Autor:Wu R; Su L; Yang PF; Min Chen L
Endereço:Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232; Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences/State Key Laboratory of Ma
Título:Altered Spatiotemporal Dynamics of Cortical Activation to Tactile Stimuli in Somatosensory Area 3b and Area 1 of Monkeys after Spinal Cord Injury.
Fonte:eNeuro; 3(5), 2016 Sep-Oct.
ISSN:2373-2822
País de publicação:United States
Idioma:eng
Resumo:Reactivation of deafferented cortex plays a key role in mediating the recovery of lost functions, although the precise mechanism is not fully understood. This study simultaneously characterized the dynamic spatiotemporal features of tactile responses in areas 3b and 1 before and 6-8 weeks after partial dorsal column lesion (DCL), and examined how the reactivation relates to the recovery of simple hand use in squirrel monkeys. A combination of high spatiotemporal resolution functional intrinsic optical imaging, microelectrode mapping, behavioral assessment, and tracer histology methods were used. Compared with the normal cortex, we found that the responses of deafferented areas 3b and 1 to 3 s of continuous 8 Hz tactile stimulation of a single digit were significantly weaker and more transient. This finding indicates a loss of response to sustained tactile stimuli. The activation area enlarged for areas 3b and 1 in both directions along digit representation (medial-lateral) and across areas (anterior-posterior). All subjects showed behavioral deficits in a food reaching-grasping-retrieving task within the first 5 weeks after DCL, but recovered at the time when optical images were acquired. Summarily, we showed that these populations of cortical neurons responded to peripheral tactile inputs, albeit in significantly altered manners in each area, several weeks after deafferentation. We propose that compromised ascending driven inputs, impaired lateral inhibition, and local integration of input signals may account for the altered spatiotemporal dynamics of the reactivated areas 3b and 1 cortices. Further investigation with large sample sizes is needed to fully characterize the effects of deafferentation on area 1 activation size.
Tipo de publicação: JOURNAL ARTICLE



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