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

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 MLPEST 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.

Recurrent psychogenic coma following tracheal stenosis repair.

Medication, intracranial hemorrhage, infarction, infection, hypoxia, organ failure, and nutritional deficiency may cause unconsciousness following successful emergence from anesthesia. A 39-year-old woman with a history of tracheal stenosis, depression, and anxiety had complete unconsciousness on 3 separate occasions following surgical repair of her tracheal stenosis. In each case, the patient's endotracheal tube had been removed; she was alert and oriented to person, time, and place; and she was admitted to the hospital for observation. Within a few hours after the tube was removed, the patient became abruptly unconscious for periods of 36, 18, and 30 hours. Each time, the results of cardiac, pulmonary, metabolic, and neurologic examinations and radiological studies were normal. We hypothesize that the patient's apparent comas were the result of an underlying conversion disorder precipitated by unresolved psychological conflict surrounding a long history of abuse in which she was repeatedly smothered by a pillow.

An optimal choice: home intravenous hydration after tonsillectomy.

Most tonsillectomies are performed as outpatient procedures in an ambulatory care facility. The postoperative period can be protracted, which can cause dehydration and readmission to the hospital. Timely intervention with home intravenous (IV) hydration can help prevent this complication. A prospective clinical trial was designed to evaluate the benefit of home IV therapy after tonsillectomy. One hundred consecutive patients underwent tonsillectomy. Fifty returned home without home IV hydration and another 50 returned home with home IV hydration. Clinical data were collected by the homecare nurse during the postoperative period. Comparison between these two groups showed that the patients with home IV hydration had less morbidity. Daily assessment of the patient by telephone is the best screening method to determine the need for IV hydration for the posttonsillectomy patient.

Protein gene product 9.5-like and calbindin-like immunoreactivity in the nasal respiratory mucosa of perinatal humans.

BACKGROUND: Protein gene product 9.5 (PGP) and calbindin-D28k (calbindin) are neuroendocrine markers that have been localized to neuroendocrine cells in the developing tracheobronchial epithelium. Neuroendocrine cells may play some role in the development of the tracheobronchial epithelium. Little is known about the development of the nasal respiratory epithelium (RE). METHODS: Nasal respiratory mucosa from fetal and newborn humans was examined to determine immunoreactivity for PGP and calbindin. RESULTS: At all stages studied, cells of different morphologies displayed PGP-like immunoreactivity (-LI) and calbindin-LI. Columnar immunoreactive cells for both markers predominated, but labeled cells of different shapes were also observed. Most labeled columnar cells were in the RE at its border with olfactory epithelium (OE); a few similarly labeled columnar cells also appeared in this OE. In the lamina propria, PGP-LI was also seen in numerous thin branching fibers. Some of these branches penetrated into the epithelium, where fiber varicosities appeared to contact cells, some of which also exhibited PGP-LI. CONCLUSION: This study demonstrates that during development the human nasal RE contains different cell types, as illustrated by the assortment of epithelial cells displaying PGP-LI and calbindin-LI among unlabeled cells. Because PGP and calbindin immunoreactivities were found within neuroendocrine cells in previous studies, the present results indicate that the developing human nasal RE also may support a number of neuroendocrine cells. Furthermore, at least some of these cells may form synaptic contacts with nerve fibers from outside the epithelium.

Distribution of OMP-, PGP 9.5- and CaBP-like immunoreactive chemoreceptor neurons in the developing human olfactory epithelium.

We have examined the distribution of olfactory marker protein (OMP), protein gene product 9.5 (PGP 9.5) and calcium-binding protein D-28k (CaBP) in the olfactory epithelium of mid- to late fetal and newborn humans using immunocytochemistry. Olfactory chemoreceptor neurons (ORNs) in a 24-week-old female fetus, a 31-week-old male fetus and a newborn male were examined. OMP-like immunoreactivity (-LI) and PGP 9.5-LI were distributed throughout ORNs at all ages. CaBP-like immunoreactivity, however, was found only in clustered or isolated fetal ORNs; in the newborn, CaBP-LI was seen only in isolated ORNs sparsely distributed throughout the OE. These findings demonstrate that human ORNs express OMP-LI nearly 4 weeks earlier in development than previously reported. PGP 9.5-LI is coincidentally abundant within these cells, suggesting it may have an important role in mature ORNs. Because the number of ORNs expressing CaBP-LI decreases during perinatal development, CaBP may be important in intracellular calcium regulation during ORN growth and maturation in the developing OE.

Olfaction and endoscopic sinus surgery.

Recent advances in endoscopic evaluation of the nose and paranasal sinuses and endoscopic sinus surgery, coupled with the development of standardized testing of olfactory acuity, have permitted improved correction of olfactory dysfunction. Conversely, increase in the number of operations performed has increased the number of injuries to the olfactory pathways. The mechanisms of loss and potential preventive and corrective measures are reviewed with a goal to minimize the numbers of these complications.

Protein gene product 9.5 in the developing and mature rat vomeronasal organ.

Protein gene product 9.5 (PGP 9.5) was immunocytochemically identified in structures of the developing and mature rat vomeronasal organ (VNO). This study started with embryos at 17 days of gestation. By this stage, PGP 9.5 was immunolocalized within both the receptor cells of the neuroepithelium and cells of the receptor-free epithelium, located on the opposite side of the lumenal space. Nerve fibers surrounding the nascent vomeronasal vein also showed PGP 9.5 immunoreactivity. Labeling was retained in the neuroepithelium and nerve fibers around the vein during development and into adulthood. Within the pool of receptor cells of the adult neuroepithelium, labeling was observed within the cytoplasm of the somata and dendrites; some receptor cells also expressed nuclear labeling. The number of immunoreactive cells in the receptor-free epithelium appeared to increase postnatally but by adulthood immunoreactivity virtually was absent. These results suggest a role for PGP 9.5 in development and maturation of the VNO and a continuing role within the steadily renewing receptor cell population found in the mature neuroepithelium. The findings of this study also suggest that PGP 9.5 is localized within the nerve fibers surrounding the vomeronasal vein from early in development through adulthood.

Elective carotid artery resection for advanced squamous cell carcinoma of the neck.

The authors performed a retrospective review of their 10-year experience of carotid artery resection without revascularization for advanced squamous cell carcinoma of the neck. From 1982 to 1991, seven patients underwent elective carotid artery resection without reconstruction at the University of Colorado Health Sciences Center in Denver. A vascular clamp with gradual carotid occlusion was placed preoperatively on four patients and awake temporary balloon occlusion of the carotid was used on three patients. The primary lesions were three laryngeal carcinomas, two oral cavity carcinomas, and two hypopharyngeal carcinomas. All seven resected specimens showed invasion of the carotid fascia on pathological exam, while five specimens exhibited actual destruction of the arterial wall. Cerebrovascular accidents occurred in two patients (one immediate and one delayed), and the perioperative mortality was 29% (one cerebrovascular accident and one gastrointestinal bleed). The five remaining patients died of locoregional recurrence or metastatic disease within 1 year after their carotid artery resection. Resection of the common or internal carotid artery without reconstruction has a significant morbidity and mortality. This operation did not improve the long-term survival in our limited series of patients who presented with histologically proven invasion of the carotid artery.

Calbindin-like immunoreactivity in epithelial cells of the newborn and adult human vomeronasal organ.

The vomeronasal organs (VNOs) of two humans, a male neonate and a female adult, were examined for immunolocalization of calbindin-D28k (calbindin) which has been immunolocalized to VNO receptor cells in other mammals. The present study demonstrates that epithelial cells within the VNOs of both subjects expressed calbindin-like immunoreactivity. These results suggest that human VNO epithelial cells of both genders express calbindin during development and in the adult.

An immuno-electron microscopic comparison of olfactory marker protein localization in the supranuclear regions of the rat olfactory epithelium and vomeronasal organ neuroepithelium.

Immuno-electron microscopy was used to examine olfactory marker protein (OMP) ultrastructural localization in the supranuclear regions of the rat olfactory epithelium (OE) and vomeronasal organ (VNO) neuroepithelium. In the OE, OMP immuno-reaction product was observed within the cytoplasm of olfactory chemoreceptor cell dendrites, vesicles and cilia. Reaction product was absent from olfactory microvillar cells and their unique microvillar projections. In the neuroepithelium of the VNO, immuno-reaction product was seen within the dendrites of the chemoreceptor cells, and in the bases of their attached microvilli; the remaining distal portions of these microvilli were unlabeled. These results demonstrate a difference in the distribution of OMP immunoreactivity over the surfaces of the rat OE and VNO. They also show that OMP immunoreactivity does not exist in the rat olfactory microvillar cells.

Ultrastructural histopathology of human olfactory dysfunction.

This paper presents electron-microscopic observations on biopsies of the olfactory mucosae of several classes of patients with smell disorders: 1) patients with loss of smell function following head injury (post-traumatic anosmics or hyposmics); 2) patients with loss of smell function following severe head colds and/or sinus infections (post-viral olfactory dysfunction, or PVOD); and 3) patients that have lacked smell function since birth (congenital anosmics). Of these, the traumatic anosmics' olfactory epithelia were quite disorganized; the orderly arrangement of supporting cells, ciliated olfactory receptor neurons, microvillar cells, and basal cells was disrupted. Although many somata of ciliated olfactory receptors were present, few of their dendrites reached the epithelial surface. The few olfactory vesicles present usually lacked olfactory cilia. The post-viral anosmics, too, had a greatly reduced number of intact ciliated olfactory receptor neurons, and most of those present were aciliate. The post-viral hyposmics had a larger population of intact, ciliated olfactory receptor cells. In the seven cases of congenital anosmia studied, no biopsies of olfactory epithelium were obtained, indicating the olfactory epithelium is either absent--or greatly reduced in area--in these individuals.

Ultrastructural neurobiology of the olfactory mucosa of the brown trout, Salmo trutta.

This paper describes four investigations of the olfactory mucosa of the brown trout: 1) the ultrastructure of the olfactory mucosa as revealed by scanning (SEM), conventional transmission (TEM), and high voltage (HVEM) electron microscopy; 2) light and electron-microscopic investigations of retrograde transport of the tracer macromolecule horseradish peroxidase (HRP) when applied to the cut olfactory nerve; 3) SEM and TEM investigations of the effects of olfactory nerve transection on cell populations within the olfactory epithelium; and 4) ultrastructural investigations of reversible degeneration of olfactory receptors caused by elevated copper concentrations. The trout olfactory epithelium contains five cell types: ciliated epithelial cells, ciliated olfactory receptor cells, microvillar olfactory receptor cells, supporting cells, and basal cells. The ciliated and microvillar olfactory receptor cells and a small number of basal cells are backfilled by HRP when the tracer is applied to the cut olfactory nerve. When the olfactory nerve is cut, both ciliated and microvillar olfactory receptor cells degenerate within 2 days and are morphologically intact again within 8 days. When wild trout are taken from their native stream and placed in tanks with elevated copper concentrations, ciliated and microvillar cells degenerate. Replacement of these trout into their stream of origin is followed by morphologic restoration of both types of olfactory receptor cells. Ciliated and microvillar receptor cells are primary sensory bipolar neurons whose dendrites make contact with the environment; their axons travel directly to the brain. Consequently, substances can be transported directly from the environment into the brain via these "naked neurons." Since fish cannot escape from the water in which they swim, and since that water may occasionally contain brain-toxic substances, the ability to close off--and later reopen--this anatomic gateway to the brain would confer a tremendous selective advantage upon animals that evolved the "brain-sparing" capacity to do so. Consequently, the unique regenerative powers of vertebrate olfactory receptor neurons may have their evolutionary origin in fishes.

Calbindin-like immunoreactivity in two peripheral chemosensory tissues of the rat: taste buds and the vomeronasal organ.

In the rat, calbindin-like immunoreactivity was observed at both the light and electron microscopic levels within the chemoreceptor neurons of the vomeronasal organ (VNO) and both intragemmal cells and associated nerve fibers of the circumvallate taste buds. All VNO neurons were immunoreactive. Only a subset of intragemmal taste cells was immunoreactive; associated immunoreactive nerve fibers were apposed to both labeled and unlabeled cells but no synaptic contacts were observed.

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

These investigations address three major questions: (1) What is the frequency of occurrence of the vomeronasal (Jacobson's) organ (VNO) in man? (2) what is the ultrastructure of the human VNO? and (3) does the VNO contain sensory receptor cells? Macroscopic and microscopic intranasal clinical examinations of over 200 persons revealed paired bilateral vomeronasal pits on the anterior 1/3 of the nasal septum in all cases. Biopsies of the vomeronasal pits and surrounding tissues were examined by light and electron microscopy. These studies showed that the vomeronasal pit leads to a closed tube, 2-8 mm long, lined by a unique pseudostratified columnar epithelium unlike any other in the human body. The anterior end of the tube is lined by tall, columnar cells with a sparse population of short microvilli. The posterior end of the VNO is lined by an epithelium that contains three morphologically distinct cell types: (1) basal cells; (2) "dark cells--tall, slender cells with heterochromatic nuclei and electron-dense cytoplasm that often contain mucigen-like granules; and (3) "light" cells--large, clear cells, extending from the basement membrane to the organ's lumen. Each "light" cell has a round, euchromatic nucleus and a clear cytoplasm that often contains many Golgi stacks and membrane-limited vesicles filled with material of modest electron density. The cell apex is tipped by a few short microvilli. Whether these cells subserve any sensory function awaits further investigation.

The intraoperative management of the thyroid gland during laryngectomy.

The standard of care of laryngeal cancer surgery is wide field excision of the larynx combined with ipsilateral thyroid lobectomy. A retrospective review of 247 laryngectomies performed between 1979 and 1989 was undertaken to determine specific intraoperative indications for thyroid gland removal. The incidence of thyroid disease in our patients with laryngeal cancer was compared to the normal population. Eight percent of thyroid specimens removed during laryngeal cancer surgery demonstrated invasion by squamous cell carcinoma. All patients having thyroid invasion had T3 or T4 laryngeal lesions that were stage IV at the time of surgery. All these lesions were found to have transglottic growth and laryngeal cartilage invasion by the pathologist. All of these patients also had abnormal thyroid glands intraoperatively and laryngeal cartilage destruction that was evident intraoperatively. Total thyroidectomy with bilateral paratracheal and pretracheal lymph node dissection is indicated when squamous cell carcinoma of the larynx involves the thyroid gland. Prophylactic ipsilateral thyroid lobectomy and isthmusectomy is warranted for large laryngeal cancers (T3, T4) that involve the anterior commissure, the subglottic area, or extend transglottically. Routine thyroid gland removal is not indicated for the majority of laryngeal cancers that do not meet the aforementioned criteria. Finally, abnormal thyroid histopathology was diagnosed in 37% of the surgical thyroid gland specimens removed during laryngectomy.

Intrinsic vasculature of the labyrinthine segment of the facial nerve--implications for site of lesion in Bell's palsy.

Recent studies of the intrinsic vasculature of the cat facial nerve have demonstrated relatively poor blood supply to the labyrinthine segment. In this study, the intrinsic vasculature of the human facial nerve was systematically evaluated in 25 temporal bones and three fresh cadaver nerves. Cross-sectional vessel counts were obtained for the labyrinthine, tympanic, and mastoid segments. Capillary densities for each segment were derived from these data. The labyrinthine segment of the human facial nerve, like that in the cat, contains fewer and smaller intrinsic blood vessels than do the mastoid and tympanic segments. This may indicate that the labyrinthine segment of the facial nerve may be more vulnerable to ischemic damage. In conjunction with the previously demonstrated narrowness of the labyrinthine fallopian canal, these findings support the contention that the labyrinthine segment is a likely site of lesion in Bell's palsy.

Hemangioma of the facial nerve: role of the geniculate capillary plexus.

Hemangioma of the facial nerve may occur more frequently than previously recognized. This benign vascular tumor most often arises in the area of the geniculate ganglion, although the reason for this site of predilection is not known. Using silicon injection and cross-sectional vessel counts, we recently demonstrated the presence of a geniculate capillary plexus (GCP) in the cat. The present study was designed to identify a similar GCP in man, if present, and to relate if to the site of predilection of hemangioma of the facial nerve. Twenty-five human facial nerves were studied in horizontally sectioned temporal bones. A clinical case of hemangioma arising at the geniculate ganglion is presented. The human geniculate ganglion has a very rich capillary plexus in contrast to the poor intrinsic vasculature of the adjacent labyrinthine segment and nioderate vasculature of the tympanic segment of the facial nerve. We hypothesize that the GCP is the origin of most hemangiomas of facial nerve. The anatomic distinctness of the geniculate gangion and GCP from the facial nerve may allow removal of these tumors with preservation of motor function in certain cases.