Human olfactory epithelial cells generated in vitro express diverse neuronal characteristics.

The olfactory epithelium constitutes the sole source of regenerating neural cells that can be obtained from a living human. As such, primary cultures derived from human olfactory epithelial biopsies can be utilized to study neurobiological characteristics of individuals under different conditions and disease states. Here, using such human cultures, we report in vitro generation of cells that exhibit a complex neuronal phenotype, encompassing receptors and signaling pathways pertinent to both olfaction and other aspects of CNS function. Using in situ hybridization, we demonstrate for the first time the native expression of olfactory receptors in cultured cells derived from human olfactory epithelial tissue. We further establish the presence and function of olfactory transduction molecules in these cells using immunocytochemistry, calcium imaging and molecular methods. Western blot analysis revealed the expression of neurotransmitter receptors for dopamine (D2R), 5-HT (5HT2C) and NMDA subtypes 1 and 2A/2B. Stimulation with dopamine or 5-HT enhanced receptor G protein activation in a subtype specific manner, based on 35S-guanosine triphosphate incorporation assay. Functional characteristics of the cultured cells are demonstrated through enhanced tyrosine phosphorylation of NMDAR 2A/2B and recruitment of signaling partners in response to NMDA stimulation. The array of neuronal characteristics observed here establishes that proliferating cells derived from the human olfactory epithelium differentiate in vitro to express functional and molecular attributes of mature olfactory neurons. These cultured neural cells exhibit neurotransmitter pathways important in a number of neuropsychiatric disorders. Their ready availability from living humans thus provides a new tool to link functional and molecular features of neural cells with clinical characteristics of individual living patients.

Increasing Incidence of Thyroid Nodules and Thyroid Cancer: Does Increased Detection of a Subclinical Reservoir Justify the Associated Anxiety and Treatment?

The incidence of thyroid cancer has been increasing over the last few decades, and it is subject to debate regarding whether the incidence is reflective of better diagnostic techniques and therefore better detection or if it is a reflection of a true increase in incidence. This increase in incidence has been most clearly manifested by an exponential increase in the diagnosis of micropapillary thyroid carcinomas. This article reviews the diagnosis of thyroid cancers, the dilemmas facing clinicians in the management of these micropapillary thyroid carcinomas, and the advances in molecular diagnostics that are being used to assist in the decision-making process. We consider the possibility of overtreatment of a relatively indolent disease and propose a less aggressive management plan in the appropriate clinical scenario.

Modulation of odor-induced increases in [Ca(2+)](i) by inhibitors of protein kinases A and C in rat and human olfactory receptor neurons.

Protein kinases A and C have been postulated to exert multiple effects on different elements of signal transduction pathways in olfactory receptor neurons. However, little is known about the modulation of olfactory responses by protein kinases in intact olfactory receptor neurons. To further elucidate the details of the modulation of odorant responsiveness by these protein kinases, we investigated the action of two protein kinase inhibitors: H89, an inhibitor of protein kinase A, and N-myristoylated EGF receptor, an inhibitor of protein kinase C, on odorant responsiveness in intact olfactory neurons. We isolated individual olfactory neurons from the adult human and rat olfactory epithelium and measured responses of the isolated cells to odorants or biochemical activators that have been shown to initiate cyclic AMP or inositol 1,4,5-trisphospate production in biochemical preparations. We employed calcium imaging techniques to measure odor-elicited changes in intracellular calcium that occur over several seconds. In human olfactory receptor neurons, the protein kinase A and C inhibitors affected the responses to different sets of odorants. In rats, however, the protein kinase C inhibitor affected responses to all odorants, while the protein kinase A inhibitor had no effect. In both species, the effect of inhibition of protein kinases was to enhance the elevation and block termination of intracellular calcium levels elicited by odorants. Our results show that protein kinases A and C may modulate odorant responses of olfactory neurons by regulating calcium fluxes that occur several seconds after odorant stimulation. The effects of protein kinase C inhibition are different in rat and human olfactory neurons, indicating that species differences are an important consideration when applying data from animal studies to apply to humans.

Progressive visual loss and ophthalmoplegia.

A 51-year-old woman with hyperthyroidism presented with a 4-week history of bilateral progressive visual loss despite treatment with oral prednisone. Her visual function improved after bilateral orbital decompression. The indications for and advantages and disadvantages of radiation therapy and orbital decompression in TAO are discussed. The management of intraocular pressure, strabismus, and lid abnormalities in TAO is also addressed.

Functionally mature olfactory neurons from two anosmic patients with Kallmann syndrome.

Patients with Kallmann syndrome (KS) exhibit hypogonadotropic hypogonadism and anosmia [Kallmann et al., Am. J. Mental Def., 48 (1944) 203-236] secondary to failure of gonadotropin-releasing hormone (GnRH)-producing neurons to migrate from the olfactory placode to the brain, and to agenesis of the olfactory bulbs. It has been hypothesized that olfactory neurons (ON) from individuals with KS are immature partly on the basis of studies in animals showing that lack of synaptic connection of ON with the olfactory bulb results in expression of immature ON [Schwob et al., J. Neurosci., 12 (1979) 880-883]. To test this assumption, we obtained olfactory tissue samples from two males diagnosed with KS on the basis of medical history and MRI studies. Both patients were anosmic. The functioning of cells isolated from biopsies taken from the upper middle turbinate and septum was studied by measuring changes in intracellular Ca2+ concentration ([Cai]) using dual excitation fluorescence microscopy. Biopsies from both patients yielded cells that morphologically appeared to be ON. Seven of 16 cells that morphologically resembled ON responded with a change in [Cai] upon stimulation with an odorant mixture. These studies show that at least some ON in KS individuals are functionally mature and suggest that complete development of the olfactory bulbs is not required for differentiation of mature human ON.

Keloid excision and recurrence prophylaxis via intradermal interferon-gamma injections: a pilot study.

Keloids are an abnormal response to wound healing distinguished by an overproduction of collagen. Thickened bundles of collagen in the reticular dermis oriented haphazardly in relation to the overlying epithelium are found in keloids, in contrast to thinner collagen fibers in a more orderly arrangement that are found in normal scars. Previous clinical trials of intralesional interferon-gamma (IFN-G) injections by Larrabee et al. and Granstein et al. showed a decrease in lesion size. These findings led to a conclusion that IFN-G would be a useful adjunct to surgical excision of keloids to aid in preventing recurrence. We performed a double-blind, placebo-controlled trial in patients with two or more keloids treated with excision and subsequent local injections of IFN-G or placebo.

Ventilation tube removal. Indications for paper patch myringoplasty.

Paper patch myringoplasties are commonly performed in children at the time of ventilation tube removal, yet no series documenting their efficacy appears in the otolaryngology literature. Over an 18-month period at the Children's Hospital of Philadelphia (Pa), 163 ventilation tube removals were performed on 131 children aged 1 to 18 years. In 95 of these ears, a paper patch myringoplasty was performed after tube removal. No significant difference (87% vs 85%) in the overall healing rate at 6 months was shown between these two groups. An analysis of the variables potentially affecting outcome revealed that healing following simple tube removal was influenced by the frequency of tube placement and by tube size. Paper patch myringoplasty significantly improved outcome (93% vs 61%) in ears with more than three previous tube placements.

Patient selection in the treatment of glabellar wrinkles with botulinum toxin type A injection.

OBJECTIVES: To determine the dose-response characteristics and side-effects profile of Clostridium botulinum type A exotoxin (Botox) used to treat glabellar wrinkles and develop guidelines for patient selection based on the nature and severity of the treated wrinkles. DESIGN: Prospective, nonrandomized pilot and electromyogram (EMG)-guided studies. SETTING: Two ambulatory care clinics at university hospitals. PARTICIPANTS: For the pilot study, volunteer samples of 23 patients with glabellar wrinkles; for the EMG-guided study, volunteer samples of 57 patients with glabellar wrinkles. INTERVENTIONS: For the pilot study, 23 patients were serially injected with up to 10.0 mouse units (MU) of Botox into each corrugator muscle; for the EMG-guided study, 57 patients were injected under EMG guidance with an initial dose of 10.0 MU of Botox into each corrugator muscle. Eleven patients with persistent corrugator activity were reinjected with 10.0 MU of Botox. MAIN OUTCOME MEASURES: For the pilot study, slide photographs were obtained before and 2 weeks after injection; for the EMG-guided study, slide photographs were obtained before and at 2 weeks and at 2 months after injection. Patients were asked to evaluate results numerically. RESULTS: For the pilot study, injection of up to 10.0 MU of Botox into each corrugator muscle produced a satisfactory improvement in 12 patients; for the EMG-guided study, 43 patients were satisfied with improvement after full abolition of corrugator or accessory lateral brow muscle activity. Women were more likely to achieve satisfactory results than were men (80% [40/50] vs 43% [3/7]; P < or = .03). Improvement was not age related. No significant side effects or complications were observed. CONCLUSIONS: Glabellar wrinkles may be satisfactorily treated with Botox injection into the corrugator supercilii muscles. Improvement is temporary, dose dependent, and may not be seen in some patients even with successful denervation of the treated muscles. Clinicians may begin treatment with a dose of 10.0 MU of Botox into each corrugator muscle, and may select candidates for injection by determining the type of wrinkle to be treated and its spreadability (glabellar spread test).

Efficacy of laser-assisted uvulopalatoplasty in obstructive sleep apnea.

Laser-assisted uvulopalatoplasty (LAUP) enlarges the oropharyngeal airway by reshaping the uvula, soft palate, and tonsillar pillars. In contrast to a uvulopalatopharyngoplasty performed in the operating room, LAUP is staged over several office visits, is less costly, is bloodless, and is not associated with velopharyngeal insufficiency or stenosis. Previous studies have documented the efficacy of LAUP in the treatment of snoring. We explore the efficacy of LAUP in the treatment of obstructive sleep apnea. Forty-eight patients comprised the study group. Each patient snored, exhibited >50% palatal collapse on Müller's maneuver, and had nocturnal polysomnography showing a respiratory disturbance index (RDI) >10. Each patient underwent LAUP until he or she reported that snoring had ceased. Of the 29 patients who underwent post-LAUP nocturnal polysomnography, 7 had RDIs <10, oxygen saturation >86%, and no cardiac arrhythmias. LAUP reduced RDI to <10 in patients with pre-LAUP apnea indexes <3 (P = 0.05) or pre-LAUP RDIs <30 (P = 0.01). The following variables did not correlate with the success of LAUP in treating obstructive sleep apnea: age, sex, pre-LAUP weight, pre-LAUP body mass index, perioperative weight change, perioperative body mass index change, pre-LAUP snoring, and post-LAUP snoring. We conclude that LAUP is an effective means of treating patients with RDIs <30.

Laryngeal chondrosarcoma: diagnosis and management.

Chondrosarcoma of the larynx is a rare malignancy accounting for 0.5% of all laryngeal tumors. We report our approach to laryngeal chondrosarcoma and review the recent literature on the subject. Our review supports the previously held opinions about sites of origin, but draws new conclusions about symptoms. In addition, we examine the controversy of conservative surgery vs. total laryngectomy.

Tracheo-gastric fistula following gastric pull-up.

Tissue damage from gastric acid may be more prevalent than currently believed following gastric pull-up. An intense anti-acid medical regimen should be instituted peri- and postoperatively. In cases where significant peptic ulcer disease exists preoperatively, an alternative means of reconstruction following laryngo-pharyngo-esophagectomy should be considered.

Botulinum toxin in otolaryngology: a review of its actions and opportunities for use.

Botulinum toxin has several important properties that make it an ideal chemical denervator. These include its high degree of specificity for the neuromuscular junction, its ability to induce temporary and reversible denervation, and its limited degree of side effects and complications. Botulinum toxin is being used safely in a wide variety of clinical settings by many different specialists. In otolaryngologic practice, it is being administered for the treatment of at least a dozen conditions, including various dysphonias, dystonias, and spasms as well as torticollis, facial nerve paralysis, and hyperkinetic facial lines. Studies have shown that botulinum toxin injections have a high rate of success in temporarily relieving symptoms.

Superficial siderosis of the central nervous system: an underdiagnosed cause of sensorineural hearing loss and ataxia.

Superficial siderosis of the central nervous system (CNS) is a rare but ultimately fatal disorder characterized by progressive hearing loss, ataxia, and dementia. Symptoms are caused by the deposition of hemosiderin in the CNS as a result of recurrent or persistent extravasation of blood into the cerebrospinal fluid. Sites most commonly involved include the cerebellum, brain stem, and eighth cranial nerve. In the past, diagnosis was most often made at autopsy, and this may account for the lack of reported cases in the otolaryngologic literature and the presumed rarity of the disorder. Now, diagnosis is confirmed by characteristic magnetic resonance imaging findings and treatment is targeted toward the source of bleeding. The diagnosis of superficial CNS siderosis should be entertained in all patients presenting with sensorineural hearing loss and ataxia.

Selectivity and response characteristics of human olfactory neurons.

Transduction mechanisms were investigated in human olfactory neurons by determining characteristics of odorant-induced changes in intracellular calcium concentration ([Ca2+]i). Olfactory neurons were freshly isolated from nasal biopsies, allowed to attach to coverslips, and loaded with the calcium-sensitive indicator fura-2. Changes in [Ca2+]i were studied in response to exposure to individual odors, or odorant mixtures composed to distinguish between transduction pathways mediated by adenosine 3'5'-monophosphate (cAMP; mix A) or inositol 1,4,5-trisphosphate (InsP3; mix B). Overall, 52% of biopsies produced one or more odorant-responsive olfactory neurons, whereas 24% of all olfactory neurons tested responded to odorant exposure with a change in [Ca2+]i. As in olfactory neurons from other species, the data suggest that odorant exposure elicited calcium influx via second-messenger pathways involving cAMP or InsP3. Unlike olfactory neurons from other species that have been tested, some human olfactory neurons responded to odorants with decreases in [Ca2+]i. Also in contrast with olfactory neurons from other species, human olfactory neurons were better able to discriminate between odorant mixtures in that no neuron responded to more than one type of odor or mixture. These results suggest the presence of a previously unreported type of olfactory transduction mechanism, and raise the possibility that coding of odor qualities in humans may be accomplished to some degree differently than in other vertebrates, with the olfactory neuron itself making a greater contribution to the discrimination process.