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At least 1,153 records · Page 64Linked to original sources
PubMed1997

A prospective study of olfaction following endoscopic sinus surgery with adjuvant medical treatment.

Few studies on the outcome of endoscopic sinus surgery have assessed the effect of this treatment on the sense of smell. We have collected data prospectively on 115 patients, before and 6 weeks after surgery. All patients had bilateral chronic rhinosinusitis. Visual analogue and a 4-grade, patient-rated symptom score related to olfaction was collected. Patients were also asked after surgery whether their sense of smell was normal, better, a little better, the same, a little worse or worse. Paired phenylethyl methyl ethyl carbinol olfactory detection thresholds were determined for 102 of the patients. All parameters showed a statistically significant improvement (P < 0.001). Acoustic rhinometry was performed pre- and postoperatively in 96 patients. The improvement in all olfactory symptom scores was found to correlate with the increase in nasal volume (Spearman rank correlation: visual analogue score, P < 0.005; 4-grade scale, P = 0.03; 'better, same, worse' scale, P = 0.001).

Chemotherapy, Adjuvant↗
PubMed2001

Factors influencing the food preference of cats.

Four individual preference tests were carried out using the same 10 castrated adult cats. The main questions investigated were: (i) do the cats prefer diets having one dominant taste or diets made from a relatively wide range of compounds of animal origin and (ii) can the preference be connected to one taste? In test 1 a dry diet (K) made by a world-renowned company having a beef taste was compared with four others (I, II, III, IV) dry foods prepared at the authors' institute in order to prevent any one of the mixtures having a predominant taste. In test 2 diets I, II, III and IV were compared with each other in the absence of diet K. In test 3 another four diets with different dominant tastes (fish, liver, poultry with fat addition and poultry without fat addition) were investigated. In test 4 the same three tastes (beef, fish and poultry) were compared with each other by using diets of three world-renowned companies. From the results the following conclusions can be drawn. Cats undoubtedly use smell in the detection and selection of food. If cats find the odour of a certain food is significantly more attractive than that of the other, they will consume it exclusively and without tasting the less attractive food. If none of the diets are especially attractive, according to smell, cats will also taste the foods and make their decision on the basis of both senses. Diets having one dominant taste result in a higher feed intake than that reached by diets without a dominant taste. If a diet is manufactured well, its dominant taste may have less effect on diet consumption. Food preference does not seem to be connected to one exclusive taste but is significantly influenced by other factors connected to the manufacturing of the diets.

Animal Feed↗
PubMed2002

[Medicolegal screening of olfactory function].

Prior to nose surgery the birhinal ability to smell should be tested routinely. From the medico-legal point of view a short screening-test consisting of 5 or 8 test items is not sufficient. It is recommended to use an identification test with 12 or 16 items. The results of these tests taken together with the patients' self estimation, the patients' history and the rhinoscopic findings offer a satisfactory evaluation of the patients' ability to smell in most cases. In case of discrepancies a more detailed test determining the TDI-value is recommendable. If the 16-identification test is used, it is sufficient to add the values of the threshold and the discrimination measurements with the "Sniffin' Sticks" to complete a full TDI score.

Algorithms↗
PubMed2005

[Rehabilitation of the olfactory sense after laryngectomy -- the larynx bypass].

BACKGROUND: Patients after laryngectomy lose their previous sense of smell, since air normally circulates via the tracheostoma and active air intake through the nose is no longer possible. The larynx bypass with a throat mask is an aid here. Nasal air circulation is made possible by this connecting piece between the mouth and tracheostoma. MATERIALS AND METHODS: Twenty patients (17 men and 3 women, mean age 60 years) who underwent laryngectomy between November 2003 and February 2004 were examined using Sniffin' Sticks with and without the larynx bypass. Moreover, patients were asked about the practicability of the larynx bypass using a visual analog scale (VAS). In addition to larynx bypass function, we were also interested in the handling for the laryngectomized patients. RESULTS: Overall, patients were able to correctly identify more items with the larynx bypass. The results were significantly better with than without the larynx bypass (p < 0.001). However, the first application of the larynx bypass was considered cumbersome. The median VAS was 5. CONCLUSION: Patients had a better sense of smell with the larynx bypass. However, due to its rather moderate practicability, the larynx bypass does not seem to be suited for daily use in its present form.

Aged↗
PubMed1978

Lability of odor pleasantness: influence of mere exposure.

Subjects judged the pleasantness of various odorants both before and after intensive exposure to a pleasant, a neutral, or an unpleasant odorant, or a short period of relaxation. Intensive exposure comprised a 30 min task of intensity discrimination. The outcome implied that exposure to an odorant can modify its own pleasantness readily, but not so readily that of other odorants. Exposure to the pleasant lemon-smelling substance citral reduced its subsequent pleasantness, whereas exposure to the unpleasant rancid-smelling substance isobutyric acid reduced its subsequent unpleasantness. The results were compatible with the notion of affective habituation. Variability of the pleasantness judgments was uniform throughout the hedonic continuum. That is, subjects agreed as much about hedonically neutral odors as about extremely pleasant and unpleasant odors.

Affect↗
PubMed1990

Odor intensity of mixed and unmixed stimuli under environmentally realistic conditions.

Subjects judged the odor intensity of single odorants and binary mixtures of fixed or varying proportions presented in the atmosphere of an environmental chamber. The subjects were exposed to the vapors either continuously (15 min) or periodically (once a minute for 15 min). As found previously, the mixtures smelled less intense than predicted from the simple sum of their unmixed components. The degree of hypoadditivity proved about the same for the four pairs of odorants studied, but varied from periodic to continuous exposure. Periodic exposure led to a greater departure from simple additivity and confirmed the presence of the phenomenon of compromise whereby the mixture can smell less intense than its stronger component alone. Continuous exposure led to a closer approximation to simple additivity and exhibited no compromise. Nevertheless, the behavior seen under continuous exposure apparently derived from a tendency for mixtures to exhibit less adaptation than their components. Whereas mixtures may seem to lack potency relative to their unmixed components, they may in fact compensate for any deficiency in momentary intensity through an increase in durability.

Attention↗
PubMed2006

Brain response to putative pheromones in lesbian women.

The progesterone derivative 4,16-androstadien-3-one (AND) and the estrogen-like steroid estra-1,3,5(10),16-tetraen-3-ol (EST) are candidate compounds for human pheromones. In previous positron emission tomography studies, we found that smelling AND and EST activated regions primarily incorporating the sexually dimorphic nuclei of the anterior hypothalamus, that this activation was differentiated with respect to sex and compound, and that homosexual men processed AND congruently with heterosexual women rather than heterosexual men. These observations indicate involvement of the anterior hypothalamus in physiological processes related to sexual orientation in humans. We expand the information on this issue in the present study by performing identical positron emission tomography experiments on 12 lesbian women. In contrast to heterosexual women, lesbian women processed AND stimuli by the olfactory networks and not the anterior hypothalamus. Furthermore, when smelling EST, they partly shared activation of the anterior hypothalamus with heterosexual men. These data support our previous results about differentiated processing of pheromone-like stimuli in humans and further strengthen the notion of a coupling between hypothalamic neuronal circuits and sexual preferences.

Adult↗
PubMed1986

Olfactory GTP-binding protein: signal-transducing polypeptide of vertebrate chemosensory neurons.

The sense of smell involves the stimulation of sensory neurons by odorants to produce depolarization and action potentials. We show that olfactory responses may be mediated by a GTP-binding protein (G protein), a homolog of the visual, hormonal, and brain signal transducing polypeptides. The olfactory G protein is identified in isolated dendritic membranes (olfactory cilia preparations) of chemosensory neurons from three vertebrate species and is shown to mediate the stimulation by odorants of the highly active adenylate cyclase in these membranes. The G protein of olfactory neurons is most similar to Gs, the hormonal stimulatory GTP-binding protein. Its alpha subunit has a molecular weight of about 42,000, and it undergoes ADP-ribosylation catalyzed by cholera toxin that leads to adenylate cyclase activation. The slight difference in molecular weights of the frog olfactory and the liver Gs alpha subunits and the higher sensitivity of olfactory adenylate cyclase to nonhydrolyzable GTP analogs are consistent with the possible existence of different Gs variants. Signal amplification due to the olfactory G protein may be responsible for the unusual acuity of the sense of smell.

Adenosine Diphosphate Ribose↗
PubMed2002

Time courses of sensory irritations due to 2-butanone and ethyl benzene exposure: influences of self-reported multiple chemical sensitivity (sMCS).

The individually different effects of exposure to comparable levels of chemicals might be partly explained by dissimilar response sensitivity towards chemicals. Multiple chemical sensitivity (MCS) might be the clinical endpoint of this altered sensitivity. Concerning a subclinical range of chemical sensitivity, 'challenge studies' with people reporting chemical sensitivity are needed to improve the knowledge about such differences. The chemical and general environmental sensitivity questionnaire (CGES) is a standardized screening tool for the selection of this group. In the present study 24 healthy male volunteers, half of them classified as sMCS-subjects, were experimentally exposed to 2-butanone and ethyl benzene at different levels (TLV-level vs. odor threshold). The strength of self-reported sensory irritations (nasal and ocular) and symptoms of bad smell were assessed, prior, during, and after the 4 hours of exposure. The time courses of sensory irritations were affected by sMCS. Across all exposure periods sMCS-subjects showed increasing symptom scores while control-subjects did not. Symptoms of bad smell were affected by three exposure-related factors (substance, level, duration) without any additional influence from the sMCS factor. Starting from these results it could be concluded that the time-depending influence of reported chemical sensitivity is most prominent for subjective data of sensory irritations.

Adult↗
PubMedDate not supplied

Self-reported illness from chemical odors in young adults without clinical syndromes or occupational exposures.

The present survey of young adult college students investigated the prevalence of self-reported illness from the smell of the five following common environmental chemicals (cacosmia): (1) pesticide, (2) automobile exhaust, (3) paint, (4) new carpet, and (5) perfume. Sixty-six percent of 643 students reported feeling ill from one or more of the five chemicals; 15% identified the smell of at least four chemicals as making them ill. Ratings of illness from pesticide correlated weakly but significantly with ratings for the largest number of individual symptoms (9 of 11); daytime tiredness and daytime grogginess both correlated at high levels of significance with illness ratings (on a 5-point scale) for four of the five chemicals. The most cacosmic group (CS) included significantly more women (79%) than the noncacosmic group (NS) (49%); women overall were more cacosmic than men (p < .001), even with the significant covariate of depression. Ratings of cacosmia correlated only weakly with scores for depression (r = 0.16), anxiety (r = 0.08), and trait shyness (r = 0.18) in the total sample. On stepwise multiple regression with cacosmia score as the dependent measure, shyness accounted for 5.8% of the variance, while depression, anxiety, sense of mastery, and repression did not enter the equation. Histories of physician-diagnosed hay fever, but not asthma, were more frequent in the CS (16%) than in the NS group (5%). Without the confounds of chronic illness or specific treatment programs, these data are similar to patterns described clinically for a subset of patients with multiple chemical sensitivities (MCS), including previous data on increased nasal resistance in MCS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1997

A memoir of olfaction.

Osphreiology, though beginning with Aristotle, and the title of a classical monograph from 1819 by Cloquet, has, like the human sense of smell itself, played a relatively modest role, compared to other sensory functions. The anatomical and physiological connections of the nose to the brain proved to be more complex than those of sight, hearing and even touch, and were therefore poorly understood before the second half of the 19th century. Moreover, the close association between smell and taste gave rise to much controversy regarding the respective roles of the first and the fifth cranial nerves. Next, came the unfolding of the evolutionary influence of cerebral structure and function--viz Broca's "limbic" concept, and the "olfactory desert" in the brains of "anosmatic" animals, Jackson's "uncinate" seizures featuring olfactory hallucinations brought the hippocampal formation into focus. Finally, there were the clinical manifestations of hyposmia and hyperosmia, from "coryza", the common cold, to injury or neoplasms causing hyposmia, as well as some endocrine alterations causing hyperosmia. (And let us not forget Charles Huysman's "Against the Grain" and Marcel Proust's evocative fragrant madeleine.).

Cranial Nerves↗
PubMed1979

Failure of oral L-histidine to influence appetite or affect zinc metabolism in man: a double-blind study.

L-Histidine, 4 g/day in gelatin capsules, was administered orally to eight normal volunteers for 2 weeks in a double-blind, balanced, crossover study with 2 weeks of placebo treatment. Body weight, serum and urinary zinc and histidine concentrations, as well as subjective ratings of appetite, taste and smell perception, and food intake were monitored. L-Histidine therapy had no significant effect on appetite, taste and smell perception, food intake, or body weight. Similarly, no effects were observed on total serum zinc, albumin-bound zinc or alpha 2-macroglobulin-bound zinc concentrations, or on urinary histidine excretion. Serum histidine concentrations increased with therapy. Urinary zinc excretion was increased significantly after 1 week, but not after 2 weeks of L-histidine therapy. It can be concluded that oral L-histidine, at the dose used, has no value as an anorectic agent.

Adult↗
PubMed1980

Influence of food odors on food aversions and preferences in patients with cancer.

One hundred thirty-three patients with cancer and 50 healthy controls judged the pleasantness of 10 common food odors and completed questionnaires on food likes or dislikes, recent smell or taste changes, development of food aversions, weight loss, decreased appetite, and early satiety. Chocolate, pork, roast beef, and chicken odors were significantly less pleasant for patients with food aversions (PA) than for controls. Ham, pork, and roast beef odors were significantly less pleasant for PA than for patients without food aversions (PNA). More PA than controls or PNA reported recent smell and taste changes for most of the 10 foods in the sample set. Roast beef was the only food on the questionnaire rated significantly less pleasant by PA than controls or PNA. There were no significant correlations between the odor hedonic scores and the questionnaire's hedonic scores for any of the 10 foods. More PA than PNA had weight loss, decreased appetite, and early satiety. Patients on chemotherapy did not have a significantly greater incidence of aversions, weight loss, decreased appetite, or early satiety than patients not receiving chemotherapy. The type of cancer appeared to have no relation to the development of food aversions.

Adolescent↗
PubMed1996

A spectroscopic mechanism for primary olfactory reception.

A novel theory of primary olfactory reception is described. It proposes that olfactory receptors respond not to the shape of the molecules but to their vibrations. It differs from previous vibrational theories (Dyson, Wright) in providing a detailed and plausible mechanism for biological transduction of molecular vibrations: inelastic electron tunnelling. Elements of the tunnelling spectroscope are identified in putative olfactory receptors and their associated G-protein. Means of calculating electron tunnelling spectra of odorant molecules are described. Several examples are given of correlations between tunnelling spectrum and odour in structurally unrelated molecules. As predicted, molecules of very similar shape but differing in vibrations smell different. The most striking instance is that of pure acetophenone and its fully deuterated analogue acetophenone-d8, which smell different despite being identical in structure. This fact cannot, it seems, be explained by structure-based theories of odour. The evidence presented here suggests instead that olfaction, like colour vision and hearing, is a spectral sense.

Amino Acid Sequence↗
PubMed1998

Effects of context on judgements of odor intensities in humans.

This study evaluated whether the intensity of previously smelled odors could unintentionally influence the subsequent judgement of odor intensity. The predicted context effect was based on the adaptation-level theory. Before and 25 min after either WEAK or STRONG biasing odor concentrations, 51 subjects were required to rate the intensity of 10 different odor concentrations of California Orange Oil. After the WEAK bias, subjects judged the odor intensity as being stronger than they did after the STRONG bias. Thus the intensity of odors smelled 25 min earlier can unintentionally influence subsequent odor intensity judgement. The findings are discussed in the light of two alternative explanations, namely, a central implicit memory process and a stimulus-level-based change at the peripheral level.

Adolescent↗
PubMed1998

Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized.

Several fundamental questions remain enigmatic concerning human olfactory sensitivity, including (i) whether detection threshold differences exist between the two sides of the nose (and, if so, whether such differences are influenced by handedness) and (ii) whether bilateral (i.e. binasal) stimulation leads to lower thresholds than unilateral stimulation (and, if so, whether the degree of facilitation is inversely related to general olfactory ability). In this study, and well-validated single staircase procedure was used to establish bilateral and unilateral detection thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130 right- and 33 left-handed subjects. No differences in sensitivity between the left and right sides of the nose were observed in either group. Bilateral thresholds were lower, on average, than unilateral thresholds when the latter were categorized in terms of left and right nares. However, the bilateral thresholds did not differ significantly from those of the side of the nose with the lower threshold. Overall smell ability, as measured by the University of Pennsylvania Smell Identification Test, did not interact with any of the test measures. These data imply that (i) the left and right sides of the nose do not systematically differ in detection threshold sensitivity for either dextrals or sinistrals and (ii) if central integration of left:right olfactory threshold sensitivity occurs, its effects do not exceed the function of the better side of the nose.

Adult↗
PubMed2003

Influences of age and sex on a microencapsulated odor memory test.

While the influences of such variables as age and sex are well established for most standardized tests of odor identification and detection, this is not the case for tests of odor memory. In this study, 231 non-smoking men and women, ranging in age from 10 to 68 years, were administered a standardized 12-item match-to-sample microencapsulated odor memory test (OMT). Anosmics were excluded from the study. Each participant was asked to smell a target odorant after its release from a microencapsulated odorant pad and then, after a delay interval of 10, 30 or 60 s, to pick the target from a similarly presented set of four odors, three of which were foils. Backward counting by threes was required during the delay intervals in an effort to minimize semantic rehearsal. Overall OMT scores were higher for women than for men, and decreased, in each sex, as a function of age in a manner similar to the age-related decline observed in tests of odor identification and detection. Performance did not change as a function of delay interval. A significant correlation between the overall OMT test scores and scores on the University of Pennsylvania Smell Identification Test was observed for women, but not for men, in accord with the notion that women may be more likely to employ semantic cues in their strategies to remember odors. The findings are discussed in light of the complexities of the construct of odor memory.

Adolescent↗
PubMed2005

Metallic taste from electrical and chemical stimulation.

A series of three experiments investigated the nature of metallic taste reports after stimulation with solutions of metal salts and after stimulation with metals and electric currents. To stimulate with electricity, a device was fabricated consisting of a small battery affixed to a plastic handle with the anode side exposed for placement on the tongue or oral tissues. Intensity of taste from metals and batteries was dependent upon the voltage and was more robust in areas dense in fungiform papillae. Metallic taste was reported from stimulation with ferrous sulfate solutions, from metals and from electric stimuli. However, reports of metallic taste were more frequent when the word 'metallic' was presented embedded in a list of choices, as opposed to simple free-choice labeling. Intensity decreased for ferrous sulfate when the nose was occluded, consistent with a decrease in retronasal smell, as previously reported. Intensity of taste evoked by copper metal, bimetallic stimuli (zinc/copper) or small batteries (1.5-3 V) was not affected by nasal occlusion. This difference suggests two distinct mechanisms for evocation of metallic taste reports, one dependent upon retronasal smell and a second mediated by oral chemoreceptors.

Chemoreceptor Cells↗