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At least 199 records · Page 11Linked to original sources
PubMed1986

Low parotid saliva calmodulin in patients with taste and smell dysfunction.

Parotid saliva calmodulin was found both in 32 normal volunteers and in 60 patients with taste and smell dysfunction; salivary calmodulin concentration was significantly lower in the patients than in the volunteers. There were no differences in salivary calmodulin concentration with respect to age, sex, or salivary flow rate in either normal volunteers or patients. When patients were categorized by diagnosis, calmodulin concentration was found to be decreased in all patient groups. The concentration of calmodulin in saliva was about 10 times that found in serum, suggesting that the parotid gland is a major source of this protein.

Adult↗
PubMed2006

To smell the immune system: olfaction, autoimmunity and brain involvement.

Aside from its recognition and warning functions, olfaction serves many purposes in the CNS and remains one of the most important means of communication with the environment. In addition to olfactory tract input, the olfactory bulb also receives and provides input to other brain centers that modify neuronal activity. Research in the field of immunology as well as in various brain illnesses is beginning to indicate the increasing relevance of smell in pathophysiology. Much of this is based on the many intricate interactions that exist between the immune system and the nervous system, and evidence exists that there may be something unique about the olfactory system that is inextricably related to immunological function. In addition, accumulating evidence confirms the existence of olfactory dysfunction in brain disease, much of which appears at early stages including multiple sclerosis, Alzheimer's Disease, Parkinson's Disease, schizophrenia and depression. Such observations may further suggest that under certain circumstances, olfactory abnormalities may be associated with autoimmune conditions. Since the organization of the olfactory system is so sensitive, impairment may be noted at an early stage. This may become important in the prediction of certain brain illnesses. While preliminary evidence may suggest a role for olfaction in the management and alleviation of various disorders, investigation of its clinical relevance remains limited.

Alzheimer Disease↗
PubMed2005

Insect olfaction: a map of smell in the brain.

Humans use three classes of photoreceptor to span the visible spectrum, but smell relies on hundreds of distinct classes of olfactory receptor neuron. Even the simple fruitfly has around 50 classes of olfactory receptor neuron. Two new studies map the projections of the great majority of these neurons into stereotyped positions in the fly brain, giving us an almost complete atlas of olfactory information transfer.

Animals↗
PubMed2005

Evaluation of the taste and smell of bottled nutritive drinks.

The purpose of this study was to evaluate the palatability of 15 bottled nutritive drinks, all commercially available in the Japanese market, using data from artificial taste and odor sensors. In gustatory sensation tests, well-trained healthy volunteers were asked to score the drinks in terms of palatability and of the four basic tastes. The results suggest that overall palatability is positively correlated with sourness intensity and fruitiness (R=0.82 and 0.86, respectively) and negatively correlated with bitterness intensity and the tasting of medicinal plants (R=-0.85 and -0.80, respectively). The sourness and bitterness intensity could be predicted by taste sensor and fruitiness could be predicted by odor sensor, respectively. By performing principal component analysis of the taste sensor data, the 15 drinks could be classified into four groups. The group classified as being predominantly sour had the highest palatability score, 3.8. By principal component analysis of odor sensor data, the drinks could also be classified into four groups and this time the group with a fruity flavor (smell) showed the highest palatability score, 3.4. In the combined analysis of both taste and odor data, products containing medicinal plants showed the lowest palatability. Finally, the combined usage of the taste and odor sensors gave rise to a three-group classification. Thus, not only the taste sensor but also the odor sensor may be useful in evaluating the palatability of bottled nutritive drinks.

Beverages↗
PubMed2005

Brain mechanisms for extracting spatial information from smell.

Forty years ago, von Békésy demonstrated that the spatial source of an odorant is determined by comparing input across nostrils, but it is unknown how this comparison is effected in the brain. To address this, we delivered odorants to the left or right of the nose, and contrasted olfactory left versus right localization with olfactory identification during brain imaging. We found nostril-specific responses in primary olfactory cortex that were predictive of the accuracy of left versus right localization, thus providing a neural substrate for the behavior described by von Békésy. Additionally, left versus right localization preferentially engaged a portion of the superior temporal gyrus previously implicated in visual and auditory localization, suggesting that localization information extracted from smell was then processed in a convergent brain system for spatial representation of multisensory inputs.

Adult↗
PubMed2004

A comparison of the sniff magnitude test and the University of Pennsylvania Smell Identification Test in children and nonnative English speakers.

The sniff magnitude test (SMT) is a reliable and rapid clinical test of olfactory function that is minimally dependent on cognitive and linguistic abilities. In this study, we compared performance on the SMT and University of Pennsylvania Smell Identification Test (UPSIT) in samples of children and nonnative English speakers. Previous research has shown that these populations perform poorly on the UPSIT as compared with young, healthy U.S. adults. Such performance differences may reflect variations in memory/cognition and language/culture rather than olfactory abilities. The UPSIT scores of children and of Indian and Chinese graduate students were found to be lower than those of young U.S. adults. By contrast, these groups did not perform more poorly than U.S. adults did on the SMT. The results are consistent with findings from our studies, with the elderly showing that performance on the UPSIT, but not the SMT, is significantly correlated with measures of memory, language and other cognitive abilities. The findings highlight the utility of the SMT when evaluating the olfactory ability of the very young, older adults and people with diverse linguistic and cultural backgrounds.

Adolescent↗
PubMed1999

Disorders of smell and taste.

As with almost any aspect of medical practice, a thorough history and physical examination coupled with a good understanding of the anatomy and physiology of an organ system are the key factors in reaching a diagnosis. The information in this article is provided to assist the internist with the diagnosis of chemosensory disorders and the differentiation of malingering or other disease process as well as providing insight into the workup, prognosis, and treatment of patients with taste and smell disorders.

Diagnosis, Differential↗
PubMedDate not supplied

Tasting and smelling as active, exploratory sensory processes.

Tasting and smelling in terrestrial vertebrates usually involve intermittent, active sampling of the chemosensory environment. This active sampling is produced by ingestive and/or respiratory behavior initiated by the central nervous system. Vascular and secretory factors modulate access to chemosensitive regions. For olfaction, per se, respiratory rhythms provide the basic pattern of intermittent odorant input. In humans and many other species, sniffing alters the respiratory pattern and moves relatively brief, higher-flow-rate samples toward the olfactory epithelium. Sniffing may be triggered by nonchemosensory events or by odorants obtained during normal respiration and can be stereotyped with regard to rate and duration of the sniffs. Within the central nervous system, processing of olfactory input can differ as a function of its temporal relationship to respiratory and sniffing rhythms. For gustation, ingestion of food and liquids provides the major source of stimulation. Since these ingestive acts are intermittent, although often repetitive and stereotyped, natural taste stimulation also is necessarily both patterned and distributed in time. Swallowing and the interingestion interval that follows tend to return the taste receptors toward a salivary baseline. During the drinking of liquid by humans, retention of a bolus in the mouth is much briefer than intersip intervals. Simulated drinking with alternating flows of artificial saliva and a sufficiently different stimulus yields constant taste intensity. Conversely, unchanging gustatory stimulation produces reductions in intensity.

Animals↗
PubMed1975

Hydrogen cyanide smell sensitivity in some Indian populations.

The ability to smell HCN has been examined in a sample of 2619 subjects from Hyderabad, Andhra Pradesh, belonging to different Indian ethnic groups. One single antimode, between concentrations of 5% and 10%, has been found. No sex nor ethnic differences were noted. Previous claims of possible sex-linked inheritance could not be confirmed.

Adolescent↗
PubMed2002

Structural determination and odor characterization of N-(2-mercaptoethyl)-1,3-thiazolidine, a new intense popcorn-like-smelling odorant.

The chemical structure of a novel, roasty, popcorn-like-smelling aroma compound formed from the reaction of fructose with cysteamine was studied by high-resolution mass spectrometry and nuclear magnetic resonance experiments. The structure of N-(2-mercaptoethyl)-1,3-thiazolidine exhibiting the extremely low odor threshold of 0.005 ng/L in air was finally confirmed by synthesis.

Cysteamine↗
PubMed2005

Identification of metallic-smelling 1-octen-3-one and 1-nonen-3-one from solutions of ferrous sulfate.

Taste threshold tests of ferrous sulfate (FeSO4) solutions have been confounded by the presence of putative odorants. To detect the presence of odorants released from these solutions solid-phase microextraction (SPME) was used to collect volatiles in the headspace above FeSO4 solutions. Gas chromatography-olfactometry of samples collected over three time periods (1, 5, and 16 h) and at two temperatures (22 and 37 degrees C) revealed the presence of several metallic-smelling odorants in the headspace. Using authentic standards, two of the odorants were conclusively identified as 1-octen-3-one and 1-nonen-3-one. Trace levels of other odorants were also detected, but dilution experiments indicated that 1-nonen-3-one was at least 10 times more potent than anything else released from the solutions. 1-Octen-3-one and 1-nonen-3-one are excellent candidates for the metallic odor responses often observed in threshold testing of solutions of FeSO4.

Chromatography, Gas↗
PubMed2004

The Smell Identification Test as a measure of olfactory identification ability in schizophrenia and healthy populations: a Rasch psychometric study.

This study examines University of Pennsylvania Smell Identification Test (UPSIT; R. L. Doty, 1995) performance in 133 controls and 54 chronic, medicated outpatients with schizophrenia (SZ) using item-response theory modeling. Results show that UPSIT items contribute to 1 factor, cover a range of 8 standard errors of measurement, and articulate 3 ability levels. Although it is not difficult enough to discriminate among persons of above-average ability, the test has diagnostic utility in detecting moderate impairment. Independent of item difficulty, 13 items differentiate patients from controls. When 45 patients and 45 controls were matched on gender and age, patient accuracy remained significantly reduced. The findings support the test's utility and demonstrate how traditional data analysis is insensitive to complexities in test performance.

Adult↗
PubMed2002

On the scents of smell in the salamander.

Our sense of smell is based on a remarkable chemical-detection system that possesses high sensitivity, broad discriminability and plastic, yet stable, function. Understanding how olfactory stimuli translate into perception is a problem of daunting complexity. How do odour-coding events in single cells correlate with emergent properties from the ensemble, and with behaviour? For comprehensive descriptions of neural function, analysis must extend from examination of how elemental principles relate to the function of the whole. The tiger salamander has long been used as an experimental model in studies of olfaction, enabling general questions about olfactory function to be approached.

Animals↗
PubMed2006

Smell images and the flavour system in the human brain.

Flavour perception is one of the most complex of human behaviours. It involves almost all of the senses, particularly the sense of smell, which is involved through odour images generated in the olfactory pathway. In the human brain, the perceptual systems are closely linked to systems for learning, memory, emotion and language, so distributed neural mechanisms contribute to food preference and food cravings. Greater recognition of the role of the brain's flavour system and its connection with eating behaviour is needed for a deeper understanding of why people eat what they do, and to generate better recommendations about diet and nutrition.

Brain↗
PubMed2001

How smell develops.

The mouse's sense of smell is built of approximately 1000 input channels. Each of these consists of a population of olfactory sensory neurons that express the same odorant receptor gene and project their axons to the same targets (glomeruli) in the olfactory bulb. A neuron must choose to express a singular receptor gene from a repertoire of approximately 1000 genes, and its axon must be wired to the corresponding glomerulus, from an array of approximately 1800 glomeruli. Genetic experiments have shown that the expressed odorant receptor specifies axonal choice of the innervated glomerulus, but it is not the only determinant. The mechanisms of odorant receptor gene choice and axonal wiring are central to the functional organization of the mammalian olfactory system. Although principles have emerged, our understanding of these processes is still limited.

Animals↗
PubMed1999

The smell map: is there a commonality of odour perception?

The normal perception of odour quality is poorly understood, so formulating meaningful tests of olfaction is difficult. While tests of odour discrimination and odour detection threshold have helped quantify olfactory dysfunction, there are not yet predictive relationships between sensitivity to particular odours and particular forms of olfactory dysfunction. Using 11 commonly encountered odours, 20 normosmics performed similarity ratings of odour pairs. Multidimensional scaling, a standard behavioural sciences data analysis method, was used to explore the perceptual relationships between the odours based on their pair-wise similarity ratings. Smell maps were created for each individual as was a common or archetypal map which indicated a commonality in individuals' odour perception, far greater than chance alone (P < 10(-6)). A preliminary analysis of four hyposmics suggests that they do not conform to the normosmic archetype. Future studies assessing the relationship between odours in the archetype should improve the selection of odours to be included in tests of odour discrimination.

Adult↗
PubMed1984

Ability to smell androstenone is genetically determined.

Some adult humans cannot detect the odor of androstenone (5 alpha-androst-16-en-3-one), a volatile steroid. To test for the presence of genetic variance associated with this trait, adult twins were tested for their ability to smell androstenone and another odorant, pyridine, that is readily perceived by most adults. Ascending concentration, two-sample (odor versus blank) forced choice tests were used to assess sensitivity to these odorants. Intraclass correlations for identical and fraternal twin detection thresholds to pyridine were small and not significantly different. However, intraclass correlations for thresholds to androstenone were significantly different, with the correlation for identical twins being greater than that for the fraternal twins. These data indicate a genetic component of variation in sensitivity to this odor. Investigations that use genetic variation could offer a new tool for studies of olfactory transduction mechanisms.

Adolescent↗
PubMed2003

Unirhinal norms for the University of Pennsylvania Smell Identification Test.

Adult normative data are presented for unirhinal administration of the University of Pennsylvania Smell Identification Test (UPSIT). Two-hundred and seventy healthy adults, aged 15-64, were administered half of the UPSIT (20 items) to each nostril. The main findings were: (1) unirhinal and birhinal performance are not equivalent necessitating the use of unirhinal norms, rather than prorated birhinal norms, (2) unirhinal performance does not differ according to nostril of presentation, (3) unirhinal performance does not differ according to sex, (4) within the age ranges studied, age accounted for only a minor proportion of the variability, and (5) being a current smoker and having lower levels of formal education contributed to reduced unirhinal UPSIT scores. Correction factors are suggested for the education and smoking variables. Unirhinal evaluation may assist in further delineating the structural integrity of specific ipsilateral brain regions and potentially aid in differential diagnosis for a number of disorders.

Adolescent↗