This paper unfolds the events, the people and the times that led up to the founding of AChemS and fashioned its character during its early formative years. It describes the path over which AChemS came, going from the original assertions and denials for the need of such an organization to its later inception and nascent development. This narration highlights such topics as the debate over the need for AChemS, the role of National Science Foundation in the founding of AChemS, the derivation of the Association's name, the choice of Sarasota and the Hyatt House as the meeting site, the generation of the programs for the early annual meetings, the adoption of the bylaws, the process of incorporation and tax deferment, and the birth of the Givaudan Lectureship. Most emphatically highlighted, however, is the enthusiasm, commitment and hard work that the members of the chemosensory research community displayed in bringing AChemS to fruition.
• We describe a patient who had perceived an unpleasant odor or taste for at least 20 years. Several other physicians had unsuccessfully treated her for infections, mucus membrane dryness and inflammation, chronic tonsillitis, and psychiatric disorders. Her workup at the State University of New York Health Science Center at Syracuse Olfactory Referral Center included a thorough history, examinations (including endoscopic studies of her nose, pharynx, and lungs), roentgenograms, taste testing, olfactory testing, and selective anesthesia of her chemosensory areas. The perception occurred only during exhalation, and appeared to be binasal. These findings, together with her morning mucus sample having a strong fishlike odor, prompted us to suspect a metabolic problem. Further testing at the Monell-Jefferson Chemosensory Clinical Research Center, Philadelphia, Pa, confirmed that she had trimethylaminuria. It is important to consider this and other treatable conditions when evaluating individuals with olfactory complaints. (Arch Otolaryngol Head Neck Surg. 1990;116:354-355)
The gradient of activity produced along the olfactory mucosa by odorant stimulation was measured by the ratio (the LB/MB ratio) of the summated neural discharges recorded from two branches of the olfactory nerve, a lateral branch (LB) supplying a mucosal region near the internal naris and a medial branch (MB) supplying a region near the external naris. Twenty-four frogs "sniffed" sixteen different odorants, each odorant at four concentrations and two flow rates. Increases in concentration and flow rate produced statistically reliable increases in the ratios; the magnitude of these increases was considerably smaller than the magnitude of the statistically significant changes that could be achieved by shifting the odorants themselves. Even the small change due to concentration depended upon the odorant presented. Thus, even at the highest physiologically possible concentrations and flow rates, the general level of the activity gradient along the mucosa appeared to be determined mainly by the particular odorant used. The relative retention time of each of these 16 different odorants was measured in a gas chromatograph fitted with a Carbowax 20M column. In general, the longer the odorant's retention time the smaller its LB/MB ratio. This suggests that the different mucosal gradients of activity are established for different odorants by a chromatographic process. The data further suggest that the mucosa behaves like a polar chromatographic column.
There are discrepancies in the literature as to whether increasing sniff flow rate increases or decreases the magnitude of the olfactory response. Earlier work from this laboratory suggested that the size and sign of the effect of flow rate might depend upon how strongly the odorant presented sorbs to the mucosa. To pursue this possibility the summated multi-unit discharges were recorded from two sites on the olfactory nerve sampling widely separated upstream and downstream regions along the flow path of the bullfrog's olfactory mucosa. Artificially produced sniffs were presented at four flow rates for each of six odorants representing a wide range of mucosal sorption strengths. The results showed a distinct relationship between the effect of flow rate and the sorption strength of the odorant presented, going from a negative effect for the weakly sorted odorants to highly positive effects for the strongly sorbed odorants. Furthermore, as expected if the flow rate effect depends upon sorption, the strongly sorbed odorants gave more positive flow rate effects as the mucosal surface over which their molecules flowed increased. Apparently, then, the effect of flow rate on the magnitude of the olfactory response can range from negative to markedly positive depending upon how strongly the odorant in question sorbs to the mucosa.
1. Fluorescence changes in the dye (WW 781) were monitored at 100 contiguous sites in a 10 x 10-pixel array on the bullfrog and salamander olfactory mucosas every 10 ms in response to odorous stimuli. The odorants were d-limonene, butanol, and amyl acetate, each presented at two concentrations with a 3:1 ratio. 2. The fluorescence signals elicited by these odorous stimuli were nearly identical in shape and time course to the electro-olfactograms (EOGs) recorded from the same animal under identical conditions. Like the EOGs, the fluorescence signals exhibited adaptation and were abolished by both Triton X-100 and ether. There was no measurable fluorescence when the tissue was not stained with the dye, and there was no change in fluorescence when, for stained tissue, nonodorized, humidified air was presented as the stimulus. 3. This technique presumably monitors the same events as the EOG, but has the advantage of simultaneously recording the odorant-induced activity from multiple sites across most of the mucosa. Thus this technique preserves subtle differences heretofore lost by other techniques both in the coarseness of their matrices and in the variability generated by trying to piece together, into one collage, results from numerous presentations given at different times. 4. In all preparations, there was a larger difference in the inherent activity patterns (derived from response magnitudes) between different odorants than between different concentrations of the same odorant. These differences were largest on the mucosa lining the floor of salamander's olfactory sac. d-limonene and butanol gave their largest responses near the internal and external nares, respectively, whereas the responses for amyl acetate were more uniform across the mucosal sheet. In contrast to the salamander, smaller differences were observed for both the roof and the floor of the bullfrog's olfactory sac. For the floor, both amyl acetate and d-limonene elicited similar patterns of response magnitude, whereas butanol differed from each of these odorants by eliciting a larger response on the anteriolateral aspect of the mucosa and a lesser response on the remainder. For the roof, different odorants produced different activity patterns, which had profiles not simply described as regions of maximal and minimal responsiveness. 5. Different inherent activity patterns based on temporal characteristics of the fluorescence responses were also observed for different odorants. Each odorant produced a different pixel-by-pixel pattern for the times at which the responses started and ended. For any given odorant, these temporal patterns paralleled the patterns given by response magnitudes.(ABSTRACT TRUNCATED AT 400 WORDS)
Distribution patterns of odorant molecules in the rat nasal olfactory region depend in large part on the detailed airflow patterns in the nasal cavity, which in turn depend on the anatomical structure. To investigate these flow patterns, we constructed an anatomically accurate finite element model of the right nasal cavity of the Sprague-Dawley rat based on horizontal (anterior–posterior) nasal cast cross sections. By numerically solving the fluid mechanical momentum and continuity equations using the finite element method, we studied the flow distribution and the complete velocity field for both inspiration and expiration throughout the nasal cavity under physiological flow rates of resting breathing and sniffing. Detailed velocity profiles, volumetric flow distributions, and streamline patterns for quasi-steady airflow are presented. S-shaped streamlines passing through the olfactory region are found to be less prevalent during expiratory than inspiratory flow leading to trapping and an increase in odorant molecule retention in the olfactory region during sniffing. The rat nasal velocity calculations will be used to study the distribution of odorant uptake onto the rat olfactory mucosa and compare it with the known anatomic location of some types of rat olfactory receptors.
Subjects wearing nasal dilators rated olfactory stimuli as being more intense compared with ratings done without nasal expansion. The results support a perceptual constancy model in olfaction. Chem. Senses 22: 177–180, 1997.
