893 resultados para Olfactory perception threshold


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Madeira wine is a fortified wine with impact in the Madeira Island’s economy. Similarly to other wines, its acidity should be well controlled in order to ensure Madeira wine quality, mostly the volatile acidity. Due to Madeira wine complex flavour, it is crucial to get a better knowledge about the volatile acidity impact in its features, namely determine the perception limit of acetic acid and ethyl acetate, as both are the main contributors for volatile acidity. Firstly, the olfactory perception threshold of volatile acidity was assessed by a trained and an untrained panel, using 5 and 10 years-old Sercial and Malvasia wines. Moreover, the current work also presents the evolution of organic acids, acetic acid and ethyl acetate during 540 days of ageing of Madeira wines (Malvasia, Bual, Verdelho and Sercial), comparing the same wines aged by both traditional ageing processes: canteiro and estufagem. Other wine samples, aged in wood casks (canteiro) for at least 5 years, were also evaluated. HS-SPME followed by GC-MS analysis was used to determine ethyl acetate concentration and IEC-HPLC-DAD was used for the organic acids determination, including acetic acid. The results indicated that acetic acid and ethyl acetate olfactory perception threshold depends essentially on wine’s age. Concerning acetic acid, the untrained panel was in average 5.45 g/L (5 years-old) and 6.22 g/L (10 years-old). Training the expert panel to recognize acetic acid odour, the values decreased for 1.44 g/L (5 years-old) and 1.87 g/L (10 years-old), but still remained higher than the established volatile acidity legal limits. Ethyl acetate threshold was similar for both panels (in average 327.97 mg/L). Both compounds tend to increase exponentially with age, being more evident in sweet wines. Organic acids in young Madeira wines depend mostly on the nature of grape varieties, but this difference is minimized with wine ageing.

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Prenatal lipopolysaccharide (LPS) exposure causes reproductive, behavioral and neurochemical defects in both dams and pups. The present study evaluated male rats prenatally treated with LPS for behavioral and neurological effects related to the olfactory system, which is the main sensorial path in rodents. Pregnant Wistar rats received 100 mu g/kg of LPS intraperitoneally (i.p.) on gestational day (GD) 9.5, and maternal behavior was evaluated. Pups were evaluated for (1) maternal odor preference, (2) aversion to cat odor, (3) monoamine levels and turnover in the olfactory bulb (OB) and (4) protein expression (via immunoblotting) within the OB dopaminergic system and glial cells. Results showed that prenatal LPS exposure impaired maternal preference and cat odor aversion and decreased dopamine (DA) levels in the OB. This dopaminergic impairment may have been due to defects in another brain area given that protein expression of the first enzyme in the DA biosynthetic pathway was unchanged in the OB. Moreover, there was no change in the protein expression of the DA receptors. The fact that the number of astrocytes and microglia was not increased suggests that prenatal LPS did not induce neuroinflammation in the OB. Furthermore, given that maternal care was not impaired, abnormalities in the offspring were not the result of reduced maternal care. (C) 2011 Elsevier Inc. All rights reserved.

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To sense myriad environmental odors, animals have evolved multiple, large families of divergent olfactory receptors. How and why distinct receptor repertoires and their associated circuits are functionally and anatomically integrated is essentially unknown. We have addressed these questions through comprehensive comparative analysis of the Drosophila olfactory subsystems that express the ionotropic receptors (IRs) and odorant receptors (ORs). We identify ligands for most IR neuron classes, revealing their specificity for select amines and acids, which complements the broader tuning of ORs for esters and alcohols. IR and OR sensory neurons exhibit glomerular convergence in segregated, although interconnected, zones of the primary olfactory center, but these circuits are extensively interdigitated in higher brain regions. Consistently, behavioral responses to odors arise from an interplay between IR- and OR-dependent pathways. We integrate knowledge on the different phylogenetic and developmental properties of these receptors and circuits to propose models for the functional contributions and evolution of these distinct olfactory subsystems.

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The neural mechanisms determining the timing of even simple actions, such as when to walk or rest, are largely mysterious. One intriguing, but untested, hypothesis posits a role for ongoing activity fluctuations in neurons of central action selection circuits that drive animal behavior from moment to moment. To examine how fluctuating activity can contribute to action timing, we paired high-resolution measurements of freely walking Drosophila melanogaster with data-driven neural network modeling and dynamical systems analysis. We generated fluctuation-driven network models whose outputs-locomotor bouts-matched those measured from sensory-deprived Drosophila. From these models, we identified those that could also reproduce a second, unrelated dataset: the complex time-course of odor-evoked walking for genetically diverse Drosophila strains. Dynamical models that best reproduced both Drosophila basal and odor-evoked locomotor patterns exhibited specific characteristics. First, ongoing fluctuations were required. In a stochastic resonance-like manner, these fluctuations allowed neural activity to escape stable equilibria and to exceed a threshold for locomotion. Second, odor-induced shifts of equilibria in these models caused a depression in locomotor frequency following olfactory stimulation. Our models predict that activity fluctuations in action selection circuits cause behavioral output to more closely match sensory drive and may therefore enhance navigation in complex sensory environments. Together these data reveal how simple neural dynamics, when coupled with activity fluctuations, can give rise to complex patterns of animal behavior.

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AIM: To identify factors that potentially influence urethral sensitivity in women. PATIENTS AND METHODS: The current perception threshold was measured by double ring electrodes in the proximal and distal urethra in 120 women. Univariate analysis using Kaplan-Meier models and multivariate analysis applying Cox regressions were performed to identify factors influencing urethral sensitivity in women. RESULTS: In univariate and multivariate analysis, women who had undergone radical pelvic surgery (radical cystectomy n = 12, radical rectal surgery n = 4) showed a significantly (log rank test P < 0.0001) increased proximal urethral sensory threshold compared to those without prior surgery (hazard ratio (HR) 4.17, 95% confidence interval (CI) 2.04-8.51), following vaginal hysterectomy (HR 4.95, 95% CI 2.07-11.85), abdominal hysterectomy (HR 5.96, 95% CI 2.68-13.23), or other non-pelvic surgery (HR 4.86, 95% CI 2.24-10.52). However, distal urethral sensitivity was unaffected by any form of prior surgery. Also other variables assessed, including age, concomitant diseases, urodynamic diagnoses, functional urethral length, and maximum urethral closure pressure at rest had no influence on urethral sensitivity in univariate as well as in multivariate analysis. CONCLUSIONS: Increased proximal but unaffected distal urethral sensory threshold after radical pelvic surgery in women suggests that the afferent nerve fibers from the proximal urethra mainly pass through the pelvic plexus which is prone to damage during radical pelvic surgery, whereas the afferent innervation of the distal urethra is provided by the pudendal nerve. Better understanding the innervation of the proximal and distal urethra may help to improve surgical procedures, especially nerve sparing techniques. Neurourol. Urodynam. (c) 2006 Wiley-Liss, Inc.

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Olfactory glomeruli are the loci where the first odor-representation map emerges. The glomerular layer comprises exquisite local synaptic circuits for the processing of olfactory coding patterns immediately after their emergence. To understand how an odor map is transferred from afferent terminals to postsynaptic dendrites, it is essential to directly monitor the odor-evoked glomerular postsynaptic activity patterns. Here we report the use of a transgenic mouse expressing a Ca(2+)-sensitive green fluorescence protein (GCaMP2) under a Kv3.1 potassium-channel promoter. Immunostaining revealed that GCaMP2 was specifically expressed in mitral and tufted cells and a subpopulation of juxtaglomerular cells but not in olfactory nerve terminals. Both in vitro and in vivo imaging combined with glutamate receptor pharmacology confirmed that odor maps reported by GCaMP2 were of a postsynaptic origin. These mice thus provided an unprecedented opportunity to analyze the spatial activity pattern reflecting purely postsynaptic olfactory codes. The odor-evoked GCaMP2 signal had both focal and diffuse spatial components. The focalized hot spots corresponded to individually activated glomeruli. In GCaMP2-reported postsynaptic odor maps, different odorants activated distinct but overlapping sets of glomeruli. Increasing odor concentration increased both individual glomerular response amplitude and the total number of activated glomeruli. Furthermore, the GCaMP2 response displayed a fast time course that enabled us to analyze the temporal dynamics of odor maps over consecutive sniff cycles. In summary, with cell-specific targeting of a genetically encoded Ca(2+) indicator, we have successfully isolated and characterized an intermediate level of odor representation between olfactory nerve input and principal mitral/tufted cell output.

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In the genus Petunia, distinct pollination syndromes may have evolved in association with bee-visitation (P. integrifolia spp.) or hawk moth-visitation (P. axillaris spp). We investigated the extent of congruence between floral fragrance and olfactory perception of the hawk moth Manduca sexta. Hawk moth pollinated P. axillaris releases high levels of several compounds compared to the bee-pollinated P. integrifolia that releases benzaldehyde almost exclusively. The three dominating compounds in P. axillaris were benzaldehyde, benzyl alcohol and methyl benzoate. In P. axillaris, benzenoids showed a circadian rhythm with an emission peak at night, which was absent from P. integrifolia. These characters were highly conserved among different P. axillaris subspecies and P. axillaris accessions, with some differences in fragrance composition. Electroantennogram (EAG) recordings using flower-blends of different wild Petunia species on female M. sexta antennae showed that P. axillaris odours elicited stronger responses than P. integrifolia odours. EAG responses were highest to the three dominating compounds in the P. axillaris flower odours. Further, EAG responses to odour-samples collected from P. axillaris flowers confirmed that odours collected at night evoked stronger responses from M. sexta than odours collected during the day. These results show that timing of odour emissions by P. axillaris is in tune with nocturnal hawk moth activity and that flower-volatile composition is adapted to the antennal perception of these pollinators.

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The University of Pennsylvania Smell Identification Test (SIT) is the most cited olfactory test in the literature because it is easy to perform and there is high test-retest reliability. There were no standardized olfaction values in a normal Brazilian population. Aim: To measure the SIT score in a group of Brazilians, and to assess the level of difficulty when implementing the test. Study design: A cross-sectional study. Materials and Methods: The SIT was applied in 25 Brazilian volunteers of various income levels who presented no olfactory complaints. Following the test, subjects answered a questionnaire with a visual analog scale (VAS) for the level of difficulty. Results: The mean in the sample of Brazilians was 32.5 (SD: 3.48) our of 40; this is below what is considered normal for US citizens. The level of difficulty was on average 26 mm (SD: 24.68) in the VAS, but it trended towards easy; 4(16%) participants did not recognize some of the odors under `alternatives`. Conclusion: In this pilot study, there was evidence of good test applicability; the score of the sample of Brazilians was just below normosmia. Further studies are needed to confirm the existence of differences between people of different income levels.

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Dissertação de mestrado em Bioengenharia

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Every year, flash floods cause economic losses and major problems for undertaking daily activity in the Catalonia region (NE Spain). Sometimes catastrophic damage and casualties occur. When a long term analysis of floods is undertaken, a question arises regarding the changing role of the vulnerability and the hazard in risk evolution. This paper sets out to give some information to deal with this question, on the basis of analysis of all the floods that have occurred in Barcelona county (Catalonia) since the 14th century, as well as the flooded area, urban evolution, impacts and the weather conditions for any of most severe events. With this objective, the identification and classification of historical floods, and characterisation of flash-floods among these, have been undertaken. Besides this, the main meteorological factors associated with recent flash floods in this city and neighbouring regions are well-known. On the other hand, the identification of rainfall trends that could explain the historical evolution of flood hazard occurrence in this city has been analysed. Finally, identification of the influence of urban development on the vulnerability to floods has been carried out. Barcelona city has been selected thanks to its long continuous data series (daily rainfall data series, since 1854; one of the longest rainfall rate series of Europe, since 1921) and for the accurate historical archive information that is available (since the Roman Empire for the urban evolution). The evolution of flood occurrence shows the existence of oscillations in the earlier and later modern-age periods that can be attributed to climatic variability, evolution of the perception threshold and changes in vulnerability. A great increase of vulnerability can be assumed for the period 1850¿1900. The analysis of the time evolution for the Barcelona rainfall series (1854¿2000) shows that no trend exists, although, due to changes in urban planning, flash-floods impact has altered over this time. The number of catastrophic flash floods has diminished, although the extraordinary ones have increased.

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Tausta: Polyneuropatia (PNP) on ääreishermoston sairaus, joka aiheuttaa laaja-alaisia, yleensä symmetrisiä vaurioita ääreishermostossa. PNP:aan johtavia syitä on satoja. Tavoitteet: Löytää parhaat neurofysiologiset menetelmät uremian, myelooman hoidossa käytettävän talidomidin sekä Fabryn taudin aiheuttaman PNP:n diagnosoimiseksi. Fabryn taudissa tutkin lisäksi ohutsäieneuropatian aiheuttamia neuropatologisia löydöksiä iholta otetusta koepalasta. Tutkimuksissa kartoitettiin lisäksi PNP:n aiheuttamien subjektiivisten oireiden korrelaatio neurofysiologisten ja neuropatologisten löydösten kanssa. Munuaisten vajaatoimintaa sairastavilla potilailla tavoitteena oli tutkia dialyysihoidon tehon vaikutusta autonomisen hermoston toimintaan sekä yhden dialyysikerran vaikutusta neurofysiologisiin löydöksiin. Aineisto ja menetelmät: I: Tutkittiin 21 uremiapotilaan sensoristen ja motoristen hermojen vasteet, värinä- sekä lämpötuntokynnykset ennen ja jälkeen hemodialyysin. Subjektiiviset PNP oireet kartoitettiin PNP oireita kysyvillä kaavakkeella. II:12 talidomidi hoitoa saavaa myeloomapotilasta, tutkimuksen menetelmät olivat samat kuin tutkimuksessa I. III: 12 Fabryn tautia sairastavaa potilasta, edellä mainittujen neurofysiologisten tutkimusten lisäksi potilailta otettiin ihobiopsia säären alueelta. Ihobiopsiasta laskettiin ohuiden hermosyiden määrä koepalan värjäyksen jälkeen. Subjektiiviset PNP oireet kartoitettiin kyselykaavakkeella. Sydämen sykevaihtelu tutkittiin levossa taajuustason analyysillä. IV: 32 uremiapotilaan autonomisen hermoston toimintaa tutkittiin sydämen sykevaihtelun aikatason analysillä, paksujen myelinoituneiden säikeiden toimintaa tutkittiin perifeeristen sensoristen hermojen mittauksilla toistetusti noin 2.9 vuoden aikana. Tulokset: Ureemisen PNP:n diagnostiikassa herkimmät tutkimukset ovat F-aaltojen parametrit alaraajojen motorisista hermoista, värinätuntokynnys alaraajoista sekä suralishermon amplitudi. Positiiviset PNP oireet uremiassa korreloivat värinätunto-kynnyksen sekä sensoristen hermojen neurografialöydösten kanssa. Neurofysiologisten tutkimusten ajankohdalla dialyysiajankohtaan nähden ei ole merkitystä. Talidomidi-PNP on pääasiassa sensorinen, mutta motoriset syyt ovat lievästi vaurioituneet. Talidomidi PNP:ssa subjektiiviset oireet korreloivat huonosti neurofysiologisten löydösten kanssa. Fabryn taudissa naisilla on oletettua enemmän ohutsäieneuropatian aiheuttamia oireita ja löydöksiä. Paksujen säikeiden löydöksiä ei tullut esiin. Ohutsäieneuropatian diagnostiikassa ihobiopsia ja kvantitatiiviset tuntokynnysmittaustestit täydentävät toisiaan. Tehokas dialyysi parantaa autonomisen hermoston toimintaa uremiapotilailla. Päätelmät: Erityyppisten polyneuropatioiden diagnostiikassa pitää etukäteen valita PNP tyypille oikeat tutkimusmenetelmät raskaiden tutkimuspatterien vähentämiseksi sekä diagnostiikan parantamiseksi. PNP:n aiheuttamat oireet ja kliiniset löydökset pitää aina tutkia, mutta yksin ne eivät ole herkkiä PNP:n diagnostiikassa.

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The increasing demand of consumer markets for the welfare of birds in poultry house has motivated many scientific researches to monitor and classify the welfare according to the production environment. Given the complexity between the birds and the environment of the aviary, the correct interpretation of the conduct becomes an important way to estimate the welfare of these birds. This study obtained multiple logistic regression models with capacity of estimating the welfare of broiler breeders in relation to the environment of the aviaries and behaviors expressed by the birds. In the experiment, were observed several behaviors expressed by breeders housed in a climatic chamber under controlled temperatures and three different ammonia concentrations from the air monitored daily. From the analysis of the data it was obtained two logistic regression models, of which the first model uses a value of ammonia concentration measured by unit and the second model uses a binary value to classify the ammonia concentration that is assigned by a person through his olfactory perception. The analysis showed that both models classified the broiler breeder's welfare successfully.

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Mortadella-type sausage manufactured using mechanically deboned chicken meat were reformulated replacing MDCM with increasing amounts of MDCM protein hydrolysates (10%, 20%, and 30%), and their physicochemical, microbiological, and sensorial characteristics were evaluated for 60 days of storage at 4 °C. The higher substitutions resulted in sausages more susceptible to lipid oxidation with higher TBARS values during storage; however, these values were lower than the organoleptic perception threshold. The sausages were darker and less red, with lower lightness (L*) and redness (a*) values than those of the control treatment. They had soft texture, which was evidenced by both the instrumental and sensory analysis. Therefore, the formulation containing 10% of MDCM protein hydrolysates proved to be the most suitable for mortadella-type sausage elaboration.