Nasal Cavity Carcinogens: Possible Routes of Metabolic Activation
D. V. M. Gerd Reznik, Sherman F. Stinson in Nasal Tumors in Animals and Man, 2017
A variety of chemicals induce nasal cavity cancer in experimental animals. Many of these compounds also give tumors in other organs, depending on the species and route of administration. In almost every case, studies on the metabolic conversion of these compounds to reactive intermediates that can covalently bind to cellular macromolecules (metabolic activation) have been carried out in tissues other than the nasal cavity. Thus, the mechanisms of metabolic activation of nasal cavity carcinogens are really not known. In this chapter, some of the major metabolic pathways that could possibly be involved in carcinogenesis by a representative group of nasal cavity carcinogens will be outlined. This includes various nitrosamines, industrial solvents, alkylating agents, haloalkanes and haloalkenes, and miscellaneous substances such as p -cresidine, phenacetin, nickel, formaldehyde, and isopropyl oils. These compounds were chosen because of their structural diversity and, in many cases, their environmental importance.
Nasal Cavity and Paranasal Sinus Cancer
Dongyou Liu in Tumors and Cancers, 2017
Tumors commonly affecting the mucus-producing tissue of the nasal cavity and paranasal sinuses include squamous cell carcinoma (SCC), malignant lymphoma, malignant melanoma, esthesioneuroblastoma, and sarcomas. The nasal cavity is the space located behind the nose, which runs along the roof of the mouth and then turns downward to the throat. Risk factors for nasal cavity and paranasal sinus cancer include tobacco smoking, chewing, and snuff; heavy alcohol use; repeated exposure to inhaled substances and human papillomavirus (HPV) infection. Sometimes people with nasal cavity or paranasal sinus cancer do not show any of these symptoms, and nasal cavity or paranasal sinus cancer is only discovered after investigation of inflammatory disease of the sinuses. By removing the entire tumor and a rim of surrounding normal tissue, surgery represents an essential part of treatment for nasal cavity and paranasal sinus cancer, especially in patients who fail to respond to radiotherapy.
Respiratory System
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
This chapter shows that oxygen from the atmosphere diffuses from a high concentration in the alveoli to a lower concentration in pulmonary circulation. The respiratory system consists of the airways, the lungs, the muscles of respiration and the areas of the nervous system which control the rate and depth of ventilation. The airways are divided into the upper and lower respiratory tract at the larynx. Air enters the larynx through the epiglottis which protects the glottis and lower respiratory tract when swallowing occurs. The upper respiratory tract consists of the nasal cavity, the mouth and the pharynx. Air is inhaled through the nose and is filtered, warmed and humidified as it passes through the nasal conchae and makes its way to posterior chamber of the nasal cavity and the upper part of the pharynx – the nasopharynx. The pharynx, oral cavity and nasal cavity also act as resonating chamber that helps to provide the distinctive sound quality of the voice.
Changes in 3D nasal cavity volume after biomimetic oral appliance therapy in adults
Published in CRANIO®, 2016
G. Dave Singh, Tammarie Heit, Derek Preble, Ravindra Chandrashekhar
Objective: In this study, the authors investigated 3D changes in nasal volume, to test the hypothesis that nasal cavity volume can be changed in adults. Methods: After obtaining informed consent, the authors undertook 3D cone-beam computerized axial tomographic (CBCT) scans of 11 consecutive adults (mean age: 37.9 years), before and after biomimetic oral appliance therapy (BOAT). The mean treatment time was 18.462.5 months. Volumetric reconstruction of the nasal cavity was undertaken, and the nasal volume was calculated in all cases. The findings were subjected to statistical analysis, using paired t-tests. Results: The mean nasal cavity volume was 41.9612.0 cm3 before treatment. After BOAT, the mean volume increased to 44.0612.7 cm3 (P50.022). Conclusions: These data support the notion that nasal cavity volume can be changed in adults. Use of BOAT might improve continuous positive airway pressure (CPAP) compliance in adults diagnosed with obstructive sleep apnea (OSA), by increasing the nasal cavity volume and decreasing nasal airflow resistance.
Reflex Activation in Allergen-induced Nasal Mucosal Vascular Reactions
Published in Acta Oto-Laryngologica, 1989
Kenneth Holmberg, Björn Bake, Ulf Pipkorn
Subjects with allergic rhinitis were challenged unilaterally with diluent and increasing doses of allergen. Challenge with the highest dose of allergen was also carried out after topical anesthesia of the nasal cavity using lidocaine. In the contralateral, unprovoked nasal cavity the mucosal blood flow was determined using the 133Xenon wash-out technique and the nasal airway resistance was determined by rhinomanometry before and after challenge. Nasal symptom scores were estimated 15 min after each challenge. Blood flow in the nasal mucosa in the unprovoked right nasal cavity decreased in a dose-dependent manner for the two highest doses of allergen where a reduction of 21% (p < 0.05) and 26% (p < 0.01) was obtained. Nasal airway resistance increased somewhat after the highest dose (p > 0.05). Topical anesthesia in the provoked nasal cavity inhibited the decrease in blood flow in the unchallenged nasal cavity. These findings suggest that the changes in the tone of the resistance vessels, but not the capacitance vessels, which are induced by allergen, are largely reflex-mediated.
Local deposition fractions of ultrafine particles in a human nasal-sinus cavity CFD model
Published in Inhalation Toxicology, 2012
Qin Jiang Ge, Kiao Inthavong, Ji Yuan Tu
Ultrafine particle deposition studies in the human nasal cavity regions often omit the paranasal sinus regions. Because of the highly diffusive nature of nanoparticles, it is conjectured that deposition by diffusion may occur in the paranasal sinuses, which may affect the residual deposition fraction that leaves the nasal cavity. Two identical CFD models of a human nasal cavity, one with sinuses and one without, were reconstructed from CT-scans to determine the uptake of ultrafine particles. In general, there was little flow passing through the paranasal sinuses. However, flow patterns revealed that some streamlines reached the upper nasal cavity near the olfactory regions. These flow paths promote particle deposition in the sphenoid and ethmoid sinuses. It was found that there were some differences in the deposition fractions and patterns for 5 and 10 nm particles between the nasal-sinus and the nasal cavity models. This difference is amplified when the flow rate is decreased and at a flow rate of 4 L/min the maximum difference was 17%. It is suggested that evaluations of nanoparticle deposition should consider some deposition occurring in the paranasal sinuses especially if flow rates are of concern.