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Odor Threshold (odor + threshold)

Distribution by Scientific Domains

Medical Sciences	50%
Chemistry	50%

Selected Abstracts

Extrapyramidal symptoms in Wilson's disease are associated with olfactory dysfunction

MOVEMENT DISORDERS, Issue 9 2006
Antje Mueller MD
Abstract Wilson's disease is a rare autosomal recessive disorder characterized by the accumulation of copper, mainly in the liver and the brain. As copper accumulation in the brain leads to disturbances in basal ganglia function, neurological-type patients typically present with hypo- and hyperkinetic extrapyramidal symptoms, with Parkinsonism being very common. Although there are numerous reports on olfactory deficits in primary neurodegenerative disorders, olfactory function has not been investigated in metabolic disorders presenting with extrapyramidal features. Twenty-four patients with Wilson's disease participated in the investigation. All patients were treated pharmacologically. They comprised patients with liver disease alone (including mild enzyme elevation in asymptomatic individuals; n = 11) and/or neurological symptoms (n = 13) at the time of testing. Twenty-one patients underwent both [18F]fluoro-2-deoxy-D-glucose positron emission tomography ([18F]FDG-PET) and magnetic resonance imaging (MRI). The severity of extrapyramidal symptoms was judged using a clinical score system ranging from 0 (no symptoms) to 3 (severe symptoms). In all patients, psychophysical testing was performed using the "Sniffin' Sticks," which involved tests for odor threshold, discrimination, and identification. Results from the present study revealed that Wilson's disease patients with neurological symptoms show a significant olfactory dysfunction compared to hepatic-type patients. Individuals who are more severely neurologically affected also present with a more pronounced olfactory deficit. Of interest, there was no significant effect of long-term treatment with penicillamine on olfactory function. Olfactory function did not correlate significantly with the presence of MRI visible lesions in the basal ganglia or with any regional glucose metabolism as measured by [18]F-FDG-PET. In conclusion, these findings indicate that the underlying pathological alterations with degeneration in the basal ganglia and neuronal loss in association with a marked increase of the copper content in this brain region play a role in the olfactory deficit. © 2006 Movement Disorder Society [source]

Smell and taste disorders in polyneuropathy: a prospective study of chemosensory disorders

ACTA NEUROLOGICA SCANDINAVICA, Issue 4 2009
J. G. Heckmann
Objective,,, The aim of the study was to assess the occurrence and the frequency of chemosensory dysfunction in patients with polyneuropathy (PNP). Methods,,, We performed a prospective observational study. Olfactory function was assessed using the standardized ,Sniffin' Sticks' test to measure odor threshold for phenyl ethyl alcohol, odor discrimination, and odor identification. Gustatory function was assessed using the standardized ,taste strips' test. In addition, we assessed etiology, neurophysiology, and severity of the PNP, and the patients' comorbidities and medication. Results,,, A total of 53 consecutive patients were enroled (15 women, 38 men; mean age 61 years); 27 of them (51%) exhibited olfactory dysfunction and 23 of them (43%) gustatory dysfunction. Patients with diabetic PNP had significantly lower taste scores than patients with inflammatory, genetic, or idiopathic PNP. In addition, odor identification was negatively correlated with PNP severity. Conclusion,,, The applied bedside tests are useful to detect chemosensory dysfunction in patients with PNP. Chemosensory dysfunction is quite frequent in these patients. [source]

Disila-Okoumal: A Silicon Analogue of the Ambergris Odorant Okoumal

CHEMBIOCHEM, Issue 12 2007
Matthias W. Büttner
Abstract Two-fold sila-substitution (C/Si exchange) in the saturated ring of the tetrahydronaphthalene skeleton of the ambery odorant okoumal (5) provides disila-okoumal (6). The okoumal isomers 5,a,d were synthesized from 1-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)ethanone (7), and the silicon analogues 6,a,d were synthesized from 1-(5,5,8,8-tetramethyl-5,8-disila-5,6,7,8-tetrahydro-2-naphthyl)ethanone (8). Detailed olfactory properties of 5,a,d and 6,a,d are reported, together with the respective threshold values. All enantiomers of okoumal and disila-okoumal exhibit typical ambery odor notes with woody facets, as is characteristic of okoumal and karanal, but a stereocenter at the 2-position was found to be of utmost importance for the odor thresholds; the lowest value of 0.31 ng per L air was measured for the 2R -configured silicon compounds 6,a and 6,c. [source]

Enantioselectivity of the musk odor sensation

CHIRALITY, Issue 8 2001
Philip Kraft
Abstract This brief review, the summary of a talk at the Symposium on Biological Chirality 2000 in Szeged, Hungary, illustrates what chiral recognition tells us about the molecular parameters of the musk odor sensation. While the enantioselectivity of odor perception is strong evidence for the key role of proteinogenic receptors in the molecular mechanism of olfaction, the quantitative and qualitative odor differences of enantiomers are often not very pronounced, as in the case of muscone (17/26). In those cases, however, where there is strong enantiodiscrimination, we find most intense musk odorants with very low odor thresholds, such as (,)-(12R)-12-methyl-9-oxa-14-tetradecanolide (35), (12R;9Z)-12-methyl-14-tetradec-9-enolide [(R)-Nirvanolide®, 38], and (,)-(4S;7R)-1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran [(,)-(4S;7R)-Galaxolide®, 57], the latter being rather rigid. We thus can assume the geometry of the musk receptor to be fairly complementary to these compounds, which therefore can serve as templates for the design of new musk odorants. Chirality 13:388,394, 2001. © 2001 Wiley-Liss, Inc. [source]