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Biomedical subjects

B W Jafek

Publications and source records attributed to B W Jafek.

At least 19 recordsLinked to original sources
PubMed1992

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.

Biopsy↗
PubMed1992

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.

Animals↗
PubMed1992

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.

Animals↗
PubMed1991

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.

Adult↗
PubMed1991

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.

Ear, Inner↗
PubMed1991

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.

Adenocarcinoma↗
PubMed1990

The effect of chronic cocaine abuse on human olfaction.

Cocaine has been used for many decades as both a stimulant and as a topical anesthetic/vasoconstrictor. Illicit "snorting" or freebase smoking has increased markedly in recent years. Decreased olfaction has been an often reported subjective complaint of cocaine abusers, but quantification of smell loss using sensitive psychophysical tests has not yet been done, leading to the present study. Eleven cocaine abusers were recruited from a drug treatment clinic. Olfaction was assessed using a butanol threshold test, the UPSIT, and a 7-item discrimination test. One patient tested anosmic, one had a mild discrimination problem, and one had a large septal perforation but was normosmic. From the present study, it appears that most cocaine abusers, even heavy users or those with intranasal damage, do not develop permanent olfactory dysfunction. It is not clear what factors may have resulted in complaints of olfactory loss in previous studies.

Adult↗
PubMed1990

Congenital anosmia.

Seven patients with congenital anosmia underwent detailed chemosensory evaluation, followed by the performance of biopsies of the olfactory region. Olfactory epithelium was not found in any of the biopsy specimens. It appears therefore that patients with congenital anosmia lack any olfactory epithelium. Several possible explanations for this finding are discussed. The most attractive hypothesis is that the olfactory placode forms either normally or abnormally during development but later degenerates and is replaced with respiratory epithelium. Only one patient in our series had congenital anosmia in association with a syndrome (Kallmann's syndrome), indicating that congenital anosmia is found more often as an isolated symptom.

Adolescent↗
PubMed1989

Peroxidase backfills suggest the mammalian olfactory epithelium contains a second morphologically distinct class of bipolar sensory neuron: the microvillar cell.

The olfactory epithelium of man, rat and some other mammals consists of 4 cell types: ciliated olfactory receptors, microvillar cells, supporting (sustentacular) cells, and basal cells. Of these, the microvillar cell is least well understood: its function is unknown. In this study, a hypothesis is put forth: that the microvillar cells in the mammalian olfactory epithelium comprise a morphologically distinct class of sensory receptor. The hypothesis is tested by injecting the cytochemical tracer macromolecule horseradish peroxidase (HRP) into the olfactory bulb of the rat, and observing its pattern of uptake in the olfactory epithelium by light and electron microscopy. In these experiments, ciliated olfactory receptors and microvillar cells backfilled with HRP: supporting and basal cells did not. The data, which support the hypothesis, indicate the microvillar cells, along with the ciliated olfactory receptors, send axons to the olfactory bulb. Consequently, it is concluded that the microvillar cell is a sensory bipolar neuron, with the cell body in the olfactory epithelium, that sends a dendrite to the site of stimulus reception at the free surface of the olfactory epithelium, and an axon to the olfactory bulb in the brain. The similarity of microvillar cells in the olfactory epithelium to 'brush cells' found throughout the respiratory tract is discussed in detail.

Animals↗
PubMed1989

Post-traumatic anosmia. Ultrastructural correlates.

Five patients suffering post-traumatic anosmia were studied at the University of Colorado Health Sciences Center, Denver. Each patient underwent psychophysical testing, clinical evaluation, and olfactory biopsy. The biopsy specimens were examined ultrastructurally and were found to vary from normal tissues. The overall appearance of the olfactory epithelium in the post-traumatic patient is disrupted and the receptor cells are distorted. Large numbers of axons are located near the basement membrane and can often be found in bundles throughout the epithelium, extending even to the mucosal surface. Olfactory cilia are rarely seen in epithelia obtained from post-traumatic patients. Bald olfactory vesicles, often containing basal bodies, are frequently observed. We postulate that in these cases, the olfactory epithelium regenerates following head trauma and the receptor cells attempt to send axons centrally. However, the cribriform plate has undergone fibrotic healing and the axons are unable to penetrate it and make contact with olfactory bulb neurons.

Adult↗
PubMed1989

Oral evaluation of patients with chemosensory disorders.

The physical examination of the patient with dysgeusia must include a thorough intraoral examination. Although the initial screening examination may be performed by clinicians of various disciplines, specialized intraoral or dental examination may be required to diagnose and manage the dysfunction.

Dysgeusia↗
PubMed1989

Surgical management of chemosensory disorders.

As additional understanding of the histopathologic basis of chemosensory dysfunction has been achieved, several actual and potential surgical approaches for correction have been devised. These currently include correction of steroid-dependent anosmia and hyposmia due to septal deviation. Posttraumatic anosmia might be correctable in the future. Surgical approaches to dysgeusia are sparse, probably due to a paucity of information on the causes of this disorder.

Humans↗
PubMed1989

Initial otolaryngologic assessment of patients with taste and smell disorders.

Patients are often referred to otolaryngologists to evaluate dysfunctions of taste or smell. A history and physical examination focused on signs and symptoms of chemosensory disorders, in combination with screening tests for taste and smell function, can quickly and easily delineate the general type and cause of the dysfunction. Several centers for chemosensory disorders referred to in this issue are available for referral to patients who need detailed testing and evaluation. Although treatment options for most taste and smell dysfunctions are limited, by categorizing disorders, we can give the patient an idea of the probable cause and prognosis of the dysfunction.

Humans↗
PubMed1987

Steroid-dependent anosmia.

In steroid-dependent anosmia (nasal polyps, inhalant allergy, anosmia), high doses of steroids will temporarily restore the sense of smell, a diagnostic test. Appropriate surgery can then be carried out, followed by low-dose, long-term steroid therapy to maintain the sense of smell. Olfactory biopsy specimens taken during the course of evaluation and treatment show electron-optically normal olfactory receptors, meaning that the probable pathogenesis of the sensory deficit is an obstruction, mechanical and possibly biochemical. Two cases of steroid-dependent anosmia are presented to detail a fully reversible anosmia using state-of-the-art techniques.

Adrenal Cortex Hormones↗