Relationship of Phenylthiocarbamide (PTC) Taster Status to Olfactory and Gustatory Function in Patients with Chemosensory Disturbances.
Τετάρτη, 13 Ιουλίου
2016, 1:02:21 μμ | Doty RL, De Fonte TP
Chem Senses. 2016 Jul 8;
Authors: Doty RL, De Fonte TP
Abstract
Poor sensitivity to the bitter taste of phenylthiocarbamide (PTC) and related substances has been associated with a number of diseases. We determined, in patients with chemosensory dysfunction from multiple etiologies, whether PTC "tasters" (n = 511) exhibit less smell and taste dysfunction than their non-PTC-tasting counterparts (n = 432) on a comprehensive battery of olfactory and gustatory tests. The proportion of tasters (54%) in our study population was much lower than that calculated from 11 North American population studies (76.5%; P < 0.0001). This taster/nontaster ratio was maintained across a range of etiologic categories. More women (60.7%) than men (45.5%) were PTC tasters (P < 0.0001). Although PTC tasting status was unrelated to scores on the olfactory tests (which included tests of odor identification, detection threshold, and odor memory/discrimination), tasters significantly outperformed nontasters on suprathreshold identification and intensity taste tests employing both bitter (caffeine) and nonbitter (sucrose, citric acid, sodium chloride) tasting stimuli. Regardless of PTC taster status, women outperformed men on the taste tests. Our findings suggest the possibility that the T2R38 gene may protect against significant olfactory dysfunction, but once such dysfunction becomes manifest at a level where professional help is sought, such protection is not evident. However, other hypotheses for this phenomenon are possible. This study demonstrates that patients with chemosensory disturbances who are PTC tasters outperform their non-PTC taster counterparts in both identifying and perceiving the intensity of a range of suprathreshold tastants, including ones that do not taste bitter.
PMID: 27402661 [PubMed - as supplied by publisher]
The emerging role of gasotransmitters in the pathogenesis of tuberculosis.
Σάββατο, 9 Ιουλίου
2016, 2:36:27 μμ | Chinta KC, Saini V, Glasgow JN,
Mazorodze JH, Rahman MA, Reddy D, Lancaster JR, Steyn AJ
Nitric Oxide. 2016 Jul 4;
Authors: Chinta KC, Saini V, Glasgow JN, Mazorodze JH, Rahman MA, Reddy D, Lancaster JR, Steyn AJ
Abstract
Mycobacterium tuberculosis (Mtb) is a facultative intracellular pathogen and the second largest contributor to global mortality caused by an infectious agent after HIV. In infected host cells, Mtb is faced with a harsh intracellular environment including hypoxia and the release of nitric oxide (NO) and carbon monoxide (CO) by immune cells. Hypoxia, NO and CO induce a state of in vitro dormancy where Mtb senses these gases via the DosS and DosT heme sensor kinase proteins, which in turn induce a set of ∼47 genes, known as the Mtb Dos dormancy regulon. On the contrary, both iNOS and HO-1, which produce NO and CO, respectively, have been shown to be important against mycobacterial disease progression. In this review, we discuss the impact of O2, NO and CO on Mtb physiology and in host responses to Mtb infection as well as the potential role of another major endogenous gas, hydrogen sulfide (H2S), in Mtb pathogenesis.
PMID: 27387335 [PubMed - as supplied by publisher]
Perceived Odor-Taste Congruence Influences Intensity and Pleasantness Differently.
Παρασκευή, 8 Ιουλίου
2016, 1:46:33 μμ | Amsellem S, Ohla K
Chem Senses. 2016 Jul 6;
Authors: Amsellem S, Ohla K
Abstract
The role of congruence in cross-modal interactions has received little attention. In most experiments involving cross-modal pairs, congruence is conceived of as a binary process according to which cross-modal pairs are categorized as perceptually and/or semantically matching or mismatching. The present study investigated whether odor-taste congruence can be perceived gradually and whether congruence impacts other facets of subjective experience, that is, intensity, pleasantness, and familiarity. To address these questions, we presented food odorants (chicken, orange, and 3 mixtures of the 2) and tastants (savory-salty and sour-sweet) in pairs varying in congruence. Participants were to report the perceived congruence of the pairs along with intensity, pleasantness, and familiarity. We found that participants could perceive distinct congruence levels, thereby favoring a multilevel account of congruence perception. In addition, familiarity and pleasantness followed the same pattern as the congruence while intensity was highest for the most congruent and the most incongruent pairs whereas intensities of the intermediary-congruent pairs were reduced. Principal component analysis revealed that pleasantness and familiarity form one dimension of the phenomenological experience of odor-taste pairs that was orthogonal to intensity. The results bear implications for the understanding the behavioral underpinnings of perseverance of habitual food choices.
PMID: 27384192 [PubMed - as supplied by publisher]
Can I trust in what I see? EEG evidence for a cognitive evaluation of perceptual constructs
Παρασκευή, 8 Ιουλίου
2016, 12:25:46 μμ | Jürgen Kornmeier, Rike Wörner,
Michael Bach
Abstract
Environmental information available to our senses is incomplete and to
varying degrees ambiguous. It has to be disambiguated in order to construct
stable and reliable percepts. Ambiguous figures are artificial examples where
perception is maximally unstable and alternates between possible
interpretations. Tiny low-level changes can disambiguate an ambiguous figure and
thus stabilize percepts. The present study compares ERPs evoked by ambiguous
stimuli and disambiguated stimulus variants across three visual categories:
geometry (Necker cube), motion (stroboscopic alternative motion stimulus, SAM)
and semantics (Boring's old/young woman). We found that (a) disambiguated
stimulus variants cause stable percepts and evoke two huge positive ERP
excursions (Cohen's effect sizes 1–2), (b) the amplitudes of these ERP effects
are inversely related to the degree of stimulus ambiguity, and (c) this pattern
of results is consistent across all three tested visual categories. This
generality across visual categories points to mechanisms at a very abstract
(cognitive) level of processing. We discuss our results in the context of a
high-level Bayesian inference unit that evaluates the reliability of perceptual
processing results, given a priori incomplete, ambiguous sensory information.
The ERP components may reflect the outcome of this reliability
estimation.
Elevated Cytosolic Cl- Concentrations in Dendritic Knobs of Mouse Vomeronasal Sensory Neurons.
Τετάρτη, 6 Ιουλίου
2016, 2:05:16 μμ | Untiet V, Moeller LM,
Ibarra-Soria X, Sánchez-Andrade G, Stricker M, Neuhaus EM, Logan DW, Gensch T,
Spehr M
Chem Senses. 2016 Jul 4;
Authors: Untiet V, Moeller LM, Ibarra-Soria X, Sánchez-Andrade G, Stricker M, Neuhaus EM, Logan DW, Gensch T, Spehr M
Abstract
In rodents, the vomeronasal system controls social and sexual behavior. However, several mechanistic aspects of sensory signaling in the vomeronasal organ remain unclear. Here, we investigate the biophysical basis of a recently proposed vomeronasal signal transduction component-a Ca(2+)-activated Cl(-) current. As the physiological role of such a current is a direct function of the Cl(-) equilibrium potential, we determined the intracellular Cl(-) concentration in dendritic knobs of vomeronasal neurons. Quantitative fluorescence lifetime imaging of a Cl(-)-sensitive dye at the apical surface of the intact vomeronasal neuroepithelium revealed increased cytosolic Cl(-) levels in dendritic knobs, a substantially lower Cl(-) concentration in vomeronasal sustentacular cells, and an apparent Cl(-) gradient in vomeronasal neurons along their dendritic apicobasal axis. Together, our data provide a biophysical basis for sensory signal amplification in vomeronasal neuron microvilli by opening Ca(2+)-activated Cl(-) channels.
PMID: 27377750 [PubMed - as supplied by publisher]
Chemical Approaches to Elucidate Enzymatic Profiles of UDP-Glucose: Glycoprotein Glucosyltransferase.
Τετάρτη, 6 Ιουλίου
2016, 1:37:45 πμ | Hachisu M, Ito Y
Chem Pharm Bull (Tokyo). 2016;64(7):687-90
Authors: Hachisu M, Ito Y
Abstract
In the endoplasmic reticulum (ER), uridine 5'-diphosphate-glucose: glycoprotein glucosyltransferase 1 (UGGT1) recognizes misfolded glycoproteins and transfers a glucose residue to the specific non-reducing end of high-mannose-type glycans. However, precise molecular mechanism by which UGGT1 senses the folding has not been understood clearly. To address this issue, various model substrates for UGGT1 have been prepared using biological approaches. Recently, we introduced chemical approaches using synthetic glycan probes that were designed for studying N-glycan processing in the ER and Golgi apparatus. Our approach can outfit the homogeneous and functionalized glycan probes. In this review, recent results on functional analysis of UGGT1 are summarized.
PMID: 27373624 [PubMed - in process]
Paracrine Induction of HIF by Glutamate in Breast Cancer: EglN1 Senses Cysteine.
Σάββατο, 2 Ιουλίου
2016, 1:11:48 μμ | Briggs KJ, Koivunen P, Cao S,
Backus KM, Olenchock BA, Patel H, Zhang Q, Signoretti S, Gerfen GJ, Richardson
AL, Witkiewicz AK, Cravatt BF, Clardy J, Kaelin WG
Cell. 2016 Jun 30;166(1):126-139
Authors: Briggs KJ, Koivunen P, Cao S, Backus KM, Olenchock BA, Patel H, Zhang Q, Signoretti S, Gerfen GJ, Richardson AL, Witkiewicz AK, Cravatt BF, Clardy J, Kaelin WG
Abstract
The HIF transcription factor promotes adaptation to hypoxia and stimulates the growth of certain cancers, including triple-negative breast cancer (TNBC). The HIFα subunit is usually prolyl-hydroxylated by EglN family members under normoxic conditions, causing its rapid degradation. We confirmed that TNBC cells secrete glutamate, which we found is both necessary and sufficient for the paracrine induction of HIF1α in such cells under normoxic conditions. Glutamate inhibits the xCT glutamate-cystine antiporter, leading to intracellular cysteine depletion. EglN1, the main HIFα prolyl-hydroxylase, undergoes oxidative self-inactivation in the absence of cysteine both in biochemical assays and in cells, resulting in HIF1α accumulation. Therefore, EglN1 senses both oxygen and cysteine.
PMID: 27368101 [PubMed - as supplied by publisher]
Enhancement of Combined Umami and Salty Taste by Glutathione in the Human Tongue and Brain.
Παρασκευή, 1 Ιουλίου
2016, 3:03:29 μμ | Goto TK, Yeung AW, Tanabe HC,
Ito Y, Jung HS, Ninomiya Y
Chem Senses. 2016 Jun 27;
Authors: Goto TK, Yeung AW, Tanabe HC, Ito Y, Jung HS, Ninomiya Y
Abstract
Glutathione, a natural substance, acts on calcium receptors on the tongue and is known to enhance basic taste sensations. However, the effects of glutathione on brain activity associated with taste sensation on the tongue have not been determined under standardized taste delivery conditions. In this study, we investigated the sensory effect of glutathione on taste with no effect of the smell when glutathione added to a combined umami and salty taste stimulus. Twenty-six volunteers (12 women and 14 men; age 19-27 years) performed a sensory evaluation of taste of a solution of monosodium L-glutamate and sodium chloride, with and without glutathione. The addition of glutathione changed taste qualities and significantly increased taste intensity ratings under standardized taste delivery conditions (P < 0.001). Functional magnetic resonance imaging showed that glutathione itself elicited significant activation in the left ventral insula. These results are the first to demonstrate the enhancing effect of glutathione as reflected by brain data while tasting an umami and salty mixture.
PMID: 27353260 [PubMed - as supplied by publisher]
Distributive processing by the iron(II)/α-ketoglutarate-dependent catalytic domains of the TET enzymes is consistent with epigenetic roles for oxidized 5-methylcytosine bases.
Παρασκευή, 1 Ιουλίου
2016, 3:03:29 μμ | Tamanaha EY, Guan S, Marks K,
Saleh L
J Am Chem Soc. 2016 Jun 30;
Authors: Tamanaha EY, Guan S, Marks K, Saleh L
Abstract
The ten-eleven translocation (TET) proteins catalyze oxidation of 5-methylcytosine ((5m)C) residues in nucleic acids to 5-hydroxymethylcytosine ((5hm)C), 5-formylcytosine ((5f)C), and 5-carboxycytosine ((5ca)C). These nucleotide bases are implicated as intermediates on the path to active demethylation, but recent reports have suggested that they might have specific regulatory roles in their own right. In this study, we present kinetic evidence showing that the catalytic domains (CDs) of TET2 and TET1 from mouse, and their homolog from Naegleria gruberi, the full-length protein NgTET1, are distributive in both chemical and physical senses as they carry out successive oxidations of a single (5m)C and multiple (5m)C residues along a polymethylated DNA substrate. We present data showing that the enzyme neither retains (5hm)C/(5f)C intermediates of preceding oxidations nor slides along a DNA substrate (without releasing it) to process an adjacent (5m)C residue. These findings contradict a recent report, which claims that oxidation of (5m)C by CD of mouse TET2 is chemically processive (iterative) (Crawford et al. J. Am. Chem. Soc. Comm. 2016, 138, 730). We further elaborate that this distributive mechanism is maintained for TETs in two evolutionarily distant homologs and posit that this mode of function allows the introduction of (5m)C forms as epigenetic markers along the DNA.
PMID: 27362828 [PubMed - as supplied by publisher]
The Communicative Work of Organizations in Shaping Argumentative Realities
Παρασκευή, 1 Ιουλίου
2016, 9:01:37 πμ
Abstract
It is argued here that large-scale organization and networked computing enable new divisions of communicative work aimed at shaping the content, direction, and outcomes of societal conversations. The challenge for argumentation theory and practice lies in attending to these new divisions of communicative work in constituting contemporary argumentative realities. Goffman’s conceptualization of participation frameworks and production formats are applied to articulate the communicative work of organizations afforded by networked computing that invents and innovates argument in all of its senses—as product, process, and procedure. Communicative work, however, may be scaffolding argumentative contexts and practices that are quite different than what has constituted past argumentative realities. The computerization of argument happens as organizations invent and innovate argument practice relative to the demands and opportunities of interorganizational communication. The cases and examples examined here suggest that argument practice is evolving around the logic of conversation and the principle of personalization. The analysis challenges argumentation theory to seriously engage with the construction of communicative contexts and the realization of ideas about disagreement management in organizational practice and information infrastructures. Directions for integrating insights from a design perspective on argument with insights from organizational and information systems theory are proposed for coming to terms with an era of large-scale organization and computerization, in particular the evolution of argument practice, the inscription of argument in the built environment, and the absorption of socio-cultural argument practices by organizations and computation.Health-related quality of life up to 1 year after radiotherapy in patients with head and neck cancer (HNC).
Τρίτη, 28 Ιουνίου
2016, 3:54:07 μμ | Loorents V, Rosell J, Salgado
Willner H, Börjeson S
| Related Articles |
Springerplus. 2016;5(1):669
Authors: Loorents V, Rosell J, Salgado Willner H, Börjeson S
Abstract
BACKGROUND: Detailed symptom specific descriptions of health-related quality of life (HRQOL), using validated questionnaires in patients with head and neck cancer (HNC) are sparse. The aim of the present study was to investigate HRQOL in patients with HNC up to 1 year after radiotherapy (RT), using two standardised questionnaires.
METHODS: The data for the present study was originally collected in a randomised, prospective study. Forty-seven patients from two RT clinics in Sweden were included to investigate the secondary aim: HRQOL. Data was recorded at baseline, completion of RT, and 3, 6, 12 months after completed RT, using the questionnaire EORTC QLQ-C30-version 3 and the disease-specific module EORTC QLQ-H&N35.
RESULTS: Most symptoms and functions deteriorated significantly by the end of RT, improved gradually by 3 and 6 months and reached baseline levels at 12 months after completed RT. However, 1 year after completed RT there were remaining significant problems in senses, dry mouth and sticky saliva.
CONCLUSIONS: Radiation therapy affects health-related quality of life in patients with head and neck cancer, both in the short and long term. Caregivers need management strategies for early detection and treatment of specific problems throughout the treatment period to help in the prevention of long-term symptoms.
PMID: 27347463 [PubMed]
Characterization of Leptospiral Chemoreceptors Using a Microscopic Agar Drop Assay
Δευτέρα, 27 Ιουνίου
2016, 7:12:14 μμ
Abstract
Bacterial chemotaxis is induced by sensing chemical stimuli via chemoreceptors embedded in the cytoplasmic membrane, enabling the cells to migrate toward nutrients or away from toxins. The chemoreceptors of Escherichia coli and Salmonella spp. have been well studied and are functionally classified on the basis of detectable substrates. The spirochete Leptospira possesses more than ten chemoreceptors and shows attractive or repellent responses against some sugars, amino acids, and fatty acids. However, the roles of these chemoreceptors have not been investigated. In this study, we conducted a chemotaxis assay called microscopic agar drop assay in combination with competition experiments, determining whether two kinds of attractants are recognized by the same type of chemoreceptor in the saprophytic Leptospira strain, Leptospira biflexa. Analyzing the competition effect observed between several pairs of chemicals, we found that L. biflexa senses sugars via chemoreceptors different from those that sense amino acids and fatty acids.Self-prioritization in vision, audition, and touch
Δευτέρα, 27 Ιουνίου
2016, 6:54:50 μμ
Abstract
To investigate self-prioritization independently of stimulus familiarity, Sui et al. (J Exp Psychol Hum Percept Perform 38:1105–1117, 2012. doi:10.1037/a0029792) introduced a new paradigm in which different geometric shapes are arbitrarily associated with self-relevant (e.g., “I”) and neutral labels (e.g., “stranger”). It has now been repeatedly demonstrated that in a subsequently presented matching task, this association leads to faster and more accurate verifications of self-relevant shape–label pairings than neutral shape–label pairings. In order to assess whether this self-prioritization effect represents a general selection mechanism in human information processing, we examined whether it is limited to the visual modality. Therefore, besides visual stimuli, auditory and vibrotactile stimuli were also associated either to self-relevant or to neutral labels. The findings demonstrate that self-prioritization represents a general tendency influencing human information processing, one that operates across the senses. Our results also highlight a top–down component to self-prioritization.Self-prioritization in vision, audition, and touch
Δευτέρα, 27 Ιουνίου
2016, 6:41:30 μμ
Abstract
To investigate self-prioritization independently of stimulus familiarity, Sui et al. (J Exp Psychol Hum Percept Perform 38:1105–1117, 2012. doi:10.1037/a0029792) introduced a new paradigm in which different geometric shapes are arbitrarily associated with self-relevant (e.g., “I”) and neutral labels (e.g., “stranger”). It has now been repeatedly demonstrated that in a subsequently presented matching task, this association leads to faster and more accurate verifications of self-relevant shape–label pairings than neutral shape–label pairings. In order to assess whether this self-prioritization effect represents a general selection mechanism in human information processing, we examined whether it is limited to the visual modality. Therefore, besides visual stimuli, auditory and vibrotactile stimuli were also associated either to self-relevant or to neutral labels. The findings demonstrate that self-prioritization represents a general tendency influencing human information processing, one that operates across the senses. Our results also highlight a top–down component to self-prioritization.Copy Number Variation in TAS2R Bitter Taste Receptor Genes: Structure, Origin, and Population Genetics.
Σάββατο, 25 Ιουνίου
2016, 2:19:21 μμ | Roudnitzky N, Risso D, Drayna D,
Behrens M, Meyerhof W, Wooding SP
Chem Senses. 2016 Jun 23;
Authors: Roudnitzky N, Risso D, Drayna D, Behrens M, Meyerhof W, Wooding SP
Abstract
Bitter taste receptor genes (TAS2Rs) harbor extensive diversity, which is broadly distributed across human populations and strongly associated with taste response phenotypes. The majority of TAS2R variation is composed of single-nucleotide polymorphisms. However, 2 closely positioned loci at 12p13, TAS2R43 and -45, harbor high-frequency deletion (Δ) alleles in which genomic segments are absent, resulting in copy number variation (CNV). To resolve their chromosomal structure and organization, we generated maps using long-range contig alignments and local sequencing across the TAS2R43-45 region. These revealed that the deletion alleles (43Δ and 45Δ) are 37.8 and 32.2kb in length, respectively and span the complete coding region of each gene (~1kb) along with extensive up- and downstream flanking sequence, producing separate CNVs at the 2 loci. Comparisons with a chimpanzee genome, which contained intact homologs of TAS2R43, -45, and nearby TAS2Rs, indicated that the deletions evolved recently, through unequal recombination in a cluster of closely related loci. Population genetic analyses in 946 subjects from 52 worldwide populations revealed that copy number ranged from 0 to 2 at both TAS2R43 and TAS2R45, with 43Δ and 45Δ occurring at high global frequencies (0.33 and 0.18). Estimated recombination rates between the loci were low (ρ = 2.7×10(-4); r = 6.6×10(-9)) and linkage disequilibrium was high (D' = 1.0), consistent with their adjacent genomic positioning and recent origin. Geographic variation pointed to an African origin for the deletions. However, no signatures of natural selection were found in population structure or integrated haplotype scores spanning the region, suggesting that patterns of diversity at TAS2R43 and -45 are primarily due to genetic drift.
PMID: 27340135 [PubMed - as supplied by publisher]
Implicit and Explicit Measurements of Affective Responses to Food Odors.
Σάββατο, 25 Ιουνίου
2016, 2:19:21 μμ | He W, de Wijk RA, de Graaf C,
Boesveldt S
Chem Senses. 2016 Jun 23;
Authors: He W, de Wijk RA, de Graaf C, Boesveldt S
Abstract
One of the main functions of olfaction is to activate approach/avoidance behavior, toward or away from people, foods, or other odor sources. These behaviors are partly automated and therefore poorly accessible via introspection. Explicit tests need therefore be complemented by implicit tests to provide additional insights into the underlying processes of these behaviors. Affective responses to seven food odors plus one control nonodor were assessed in 28 female participants (18-30 years) using explicit tests [pleasantness, intensity, and non-verbal emotional ratings (PrEmo)] as well as implicit tests that reflect dynamic expressive emotional reactions (facial expressions) as well as behavioral-preparation responses (autonomic nervous system responses: heart rate, skin conductance, and skin temperature). Explicit tests showed significant differences in pleasantness (P < 0.05), and all PrEmo emotions (P < 0.05) except shame. Explicit emotional responses were summarized by valence (explaining 83% of the responses variance) and arousal (14%) as principal components. Early implicit facial and ANS responses (after 1s) seem to reflect the odors' arousal, whereas later ANS responses (after 3-4s) reflected the odors' valence. The results suggest that explicit measures primarily reflect the odors' valence, as result of from relatively long (conscious) processing, which may be less relevant for odor acceptance in the real world where fast and automated processes based on arousal may play a larger role.
PMID: 27340136 [PubMed - as supplied by publisher]
Editorial Board.
Σάββατο, 25 Ιουνίου
2016, 2:19:21 μμ
Chem Senses. 2016 Jul;41(6):NP
Authors:
PMID: 27340207 [PubMed - in process]
Subscriptions.
Σάββατο, 25 Ιουνίου
2016, 2:19:21 μμ
Chem Senses. 2016 Jul;41(6):NP
Authors:
PMID: 27340208 [PubMed - in process]
Table of Contents.
Σάββατο, 25 Ιουνίου
2016, 2:19:21 μμ
Chem Senses. 2016 Jul;41(6):NP
Authors:
PMID: 27340209 [PubMed - in process]
