A novel family of genes encoding putative pheromone receptors in mammals

Smell and taste disorders are common in the general population, yet little is known about their nature or cause. This article describes a study of 750 patients with complaints of abnormal smell or taste perception from the University of Pennsylvania Smell and Taste Center, Philadelphia. Major findings suggest that: chemosensory dysfunction influences quality of life; complaints of taste loss usually reflect loss of smell function; upper respiratory infection, head trauma, and chronic nasal and paranasal sinus disease are the most common causes of the diminution of the sense of smell, with head trauma having the greatest loss; depression frequently accompanies chemosensory distortion; low body weight accompanies burning mouth syndrome; estrogens protect against loss of the sense of smell in postmenopausal women; zinc therapy may provide no benefit to patients with chemosensory dysfunction; and thyroid hormone function is associated with oral sensory distortion. The findings are discussed in relation to management of patients with chemosensory disturbances.

https://jamanetwork.com/journals/jamaotolaryngology/articlepdf/619670/archotol_117_5_015.pdf

Smell and taste disorders, a study of 750 patients from the University of Pennsylvania Smell and Taste Center.

Transport of drugs from the nasal cavity to the central nervous system

As research on sensation and perception has grown more sophisticated during the last century, new adaptive methodologies have been developed to increase efficiency and reliability of measurement. An experimental procedure is said to be adaptive if the physical characteristics of the stimuli on each trial are determined by the stimuli and responses that occurred in the previous trial or sequence of trials. In this paper, the general development of adaptive procedures is described, and three commonly used methods are reviewed. Typically, a threshold value is measured using these methods, and, in some cases, other characteristics of the psychometric function underlying perceptual performance, such as slope, may be developed. Results of simulations and experiments with human subjects are reviewed to evaluate the utility of these adaptive procedures and the special circumstances under which one might be superior to another.

/pdf/adaptive-procedures-in-psychophysical-research-4i6hwqfvr0.pdf

Adaptive procedures in psychophysical research.

Nanoparticles for direct nose-to-brain delivery of drugs.

This report gives a detailed description of the fine structure of the olfactory mucosa in man. Using a special biopsy instrument and technique, fresh biopsies of olfactory epithelium were taken under local anaesthesia from eight normal volunteers. Transmission electron microscopy reveals that human olfactory epithelium has four major cell types: ciliated olfactory receptors, supporting cells, basal cells and microvillar cells. The ciliated olfactory receptors, as in other mammals, are bipolar neurons; the dendrite tip, modified to form the olfactory vesicle, bears 10–30 cilia that lack dynein arms. The supporting cells, markedly different from the goblet cells of respiratory epithelium, are not specialized for mucus secretion. Instead they are equipped to contribute materials to, and remove materials from, the surface mucus. The basal cells are stem cells that serve to replace epithelial cells and receptors lost during normal turnover or injury. In addition to ciliated olfactory neurons, supporting cells and basal cells, the human olfactory mucosa contains a distinct fourth cell type, the microvillar cell, of unknown function. The apical pole of the cell sends a tuft of short microvilli into the nasal cavity; its basal pole gives rise to a slender cytoplasmic process that resembles an axon. If microvillar cells prove to be sensory cells, the current concept of the human olfactory epithelium will have to be revised to include two morphologically distinct classes of receptors.

The fine structure of the olfactory mucosa in man.

Electron microscopy of human olfactory epithelium reveals a new cell type: The microvillar cell

It has been shown that olfactory epithelium can be safely biopsied from the living, intact human being. Observations of the ultrastructure of this epithelium shows changes that can then be correlated with the etiology and degree of olfactory loss, allowing a greater understanding of both normal transduction and of the pathology of dysfunction. Examples of the common forms of olfactory dysfunction are presented and discussed. Additionally, the technique will allow additional immunohistochemical and molecular study of the tissue, will increase the understanding of both normal and pathological function and should translate to new therapeutic regimens.

/pdf/biopsies-of-human-olfactory-epithelium-5gtct0hlq1.pdf

Biopsies of Human Olfactory Epithelium

The vomeronasal (Jacobson's) organ in man: ultrastructure and frequency of occurrence.

This paper evaluates the use of a maximum-likelihood adaptive staircase psychophysical procedure (ML-PEST), originally developed in vision and audition, for measuring detection thresholds in gustation and olfaction. The basis for the psychophysical measurement of thresholds with the ML-PEST procedure is developed. Then, two experiments and four simulations are reported. In the first experiment, ML-PEST was compared with the Wetherill and Levitt up-down staircase method and with the Cain ascending method of limits in the measurement of butyl alcohol thresholds. The four Monte Carlo simulations compared the three psychophysical procedures. In the second experiment, the test-retest reliability of ML-PEST for measuring NaCl and butyl alcohol thresholds was assessed. The results indicate that the ML-PEST method gives reliable and precise threshold measurements. Its ability to detect malingerers shows considerable promise. It is recommended for use in clinical testing.

/pdf/fast-and-accurate-measurement-of-taste-and-smell-thresholds-4omvcp2q8s.pdf

Bruce W. Jafek

Papers

The fine structure of the olfactory mucosa in man.

Electron microscopy of human olfactory epithelium reveals a new cell type: The microvillar cell

Biopsies of Human Olfactory Epithelium

The vomeronasal (Jacobson's) organ in man: ultrastructure and frequency of occurrence.

Fast and accurate measurement of taste and smell thresholds using a maximum-likelihood adaptive staircase procedure.