Effect of wearing masks on odor detection and recognition.

BACKGROUND: The effect of wearing masks on olfaction remains unclear. OBJECTIVES: This study aimed to clarify the differences between the effects of no masks, surgical masks, and N95 respirator masks by conducting both identification and threshold olfaction tests. METHODS: Young, healthy volunteers aged ≥ 18 years and < 30 years without awareness of apparent olfactory disorder were included. All participants filled out a questionnaire on olfaction and completed an acuity smell identification test (Open Essence test) and an olfactory threshold test (T&T olfactometry) while wearing no masks, surgical masks, or N95 respirator masks. RESULTS: In the Open Essence tests, the no-mask group score was significantly higher than those of the surgical- and N95-mask groups. Using T&T olfactometry, the median-detection threshold of the no-mask group was significantly lower than that of the surgical-mask group, and the surgical-mask group threshold was significantly lower than that of the N95-mask group. Similar patterns were observed for the median-recognition threshold. CONCLUSIONS: Wearing masks, especially an N95 mask, reduces the ability to detect and identify odors. This disadvantage should be considered by professionals such as healthcare workers, who require proper olfaction to perform appropriate tasks.

Fatty acid binding protein type 7 deficiency preserves auditory function in noise-exposed mice.

Fatty acid-binding protein 7 (FABP7) is vital for uptake and trafficking of fatty acids in the nervous system. To investigate the involvement of FABP7 in noise-induced hearing loss (NIHL) pathogenesis, we used Fabp7 knockout (KO) mice generated via CRISPR/Cas9 in the C57BL/6 background. Initial auditory brainstem response (ABR) measurements were conducted at 9 weeks, followed by noise exposure at 10 weeks. Subsequent ABRs were performed 24 h later, with final measurements at 12 weeks. Inner ears were harvested 24 h after noise exposure for RNA sequencing and metabolic analyses. We found no significant differences in initial ABR measurements, but Fabp7 KO mice showed significantly lower thresholds in the final ABR measurements. Hair cell survival was also enhanced in Fabp7 KO mice. RNA sequencing revealed that genes associated with the electron transport chain were upregulated or less impaired in Fabp7 KO mice. Metabolomic analysis revealed various alterations, including decreased glutamate and aspartate in Fabp7 KO mice. In conclusion, FABP7 deficiency mitigates cochlear damage following noise exposure. This protective effect was supported by the changes in gene expression of the electron transport chain, and in several metabolites, including excitotoxic neurotransmitters. Our study highlights the potential therapeutic significance of targeting FABP7 in NIHL.

Effects of zinc deficiency on the regeneration of olfactory epithelium in mice.

The olfactory epithelium can regenerate after damage; however, the regeneration process is affected by various factors, such as viral infections, head trauma, and medications. Zinc is an essential trace element that has important roles in organ development, growth, and maturation. Zinc also helps regulate neurotransmission in the brain; nevertheless, its relationship with olfactory epithelium regeneration remains unclear. Therefore, we used a severe zinc deficiency mouse model to investigate the effects of zinc deficiency on olfactory epithelium regeneration. Male wild-type C57BL/6 mice were divided into zinc-deficient and control diet groups at the age of 4 weeks, and methimazole was administered at the age of 8 weeks to induce severe olfactory epithelium damage. We evaluated the olfactory epithelium before and 7, 14, and 28 days after methimazole administration by histologically analyzing paraffin sections. RNA sequencing was also performed at the age of 8 weeks before methimazole administration to examine changes in gene expression caused by zinc deficiency. In the zinc-deficient group, the regenerated olfactory epithelium thickness was decreased at all time points, and the numbers of Ki-67-positive, GAP43-positive, and olfactory marker protein-positive cells (i.e. proliferating cells, immature olfactory neurons, and mature olfactory neurons, respectively) failed to increase at some time points. Additionally, RNA sequencing revealed several changes in gene expression, such as a decrease in the expression of extracellular matrix-related genes and an increase in that of inflammatory response-related genes, in the zinc-deficient group. Therefore, zinc deficiency delays olfactory epithelium regeneration after damage in mice.

Endoscopic Resection of Nasal Mucosal Melanoma Using Temporary Transseptal Access.

Nasal mucosal melanoma (NMM) is a rare tumor with a poor prognosis. Although an endoscopic resection of malignant nasal tumor now becomes a treatment of choice when the surgical margin can be secured, it is still controversial. We report three cases of NMM that was successfully removed en bloc with clear margins by endoscopic surgery with temporal transseptal access. Cases of a 78-year-old woman, an 83-year-old man, and an 81-year-old man with NMM arising from the inferior turbinate who underwent endoscopic resection of the tumor are discussed in detail. We made temporal transseptal access using septal mucosal flaps. We moved the nasal cavity-occupying tumor to the contralateral side to create a working space to perform endoscopic en bloc resections. This technique is simple yet effective and less invasive than open craniofacial resections for removing malignancies arising from the inferior turbinate.

Effect of treatments for head and neck cancer on sinus shadow on computed tomography.

OBJECTIVE: Head and neck surgeries may cause changes in the nasal airflow, and radiotherapy irreversibly damages paranasal sinus epithelial cells. Some chemotherapeutic drugs have been reported to negatively affect airway ciliary activity in mice, and chronic rhinosinusitis could be an adverse effect of head and neck cancer (HNC) treatment. To evaluate whether HNC treatment is a risk factor for developing sinonasal mucosal thickening that may reflect paranasal sinus inflammation, we compared pre- and post-treatment paranasal sinus computed tomography (CT) images of patients treated for HNC at a single university hospital. METHODS: The patients who received curative treatment for HNC (oral, pharyngeal, and laryngeal cancers) and started receiving first-line therapy between January 2015 and December 2019 were included. Data on age, sex, primary lesion, clinical stage, treatment, smoking history, drinking history, comorbidities (diabetes and chronic lung disease), and pre- and post-treatment (three months and one year after the final treatment) paranasal sinus CT images were analyzed from medical records. Pre- and post-treatment paranasal sinus CT images were scored using the Lund-Mackay (LM) staging system. RESULTS: In total, 245 patients participated in this study. Three months after the final treatment, 80.4% of patients had no change in their total LM scores (p=0.621). Almost 80% of patients who underwent total laryngectomy also had no change in their total LM scores (p=0.833). One-third of patients with nasopharyngeal cancer (NPC) had worse LM scores after treatment (5/15), although no significant difference was observed (p=0.171). None of the various factors collected were significantly related to changes in LM scores three months after the completion of treatment. One year after the final treatment, 211 patients were included and no significant changes in the pre-and post-LM scores were observed in the same analyses, while changes in LM scores were significantly different between T categories (T1-2 vs. T3-4) (p=0.020). CONCLUSION: We found no significant changes in the LM scores after HNC treatment in all the patients, which implies that HNC treatment may not be an apparent risk factor for sinonasal mucosal inflammation.

Preoperative Endovascular Embolization in an Easily Bleeding Respiratory Epithelial Adenomatoid Hamartoma of the Olfactory Cleft: A Case Report.

Respiratory epithelial adenomatoid hamartomas (REAHs) are rare tumors occurring in the nasal cavity and sinuses, and their etiology is unknown. REAH is a relatively recently established lesion and is often misdiagnosed as nasal polyposis or other tumors. Preoperative endovascular embolization for sinonasal tumors is now widely accepted as an effective method to reduce blood loss, soften the tumor, and facilitate surgical procedures. However, to the best of our knowledge, there are no reports of the requirement for preoperative embolization in the management of REAH. Here, we present a 70-year-old man with an easily bleeding REAH of the olfactory cleft, vascularized by branches of the bilateral internal and external carotid arteries. We removed the tumor endoscopically after preoperative embolization of the bilateral sphenopalatine arteries. Histological investigation revealed an intratumoral hemorrhage accompanying the REAH, with no evidence of a residual or recurrent tumor during the last follow-up at 3 months. In conclusion, accurate preoperative diagnosis and proper preoperative interventions such as embolization are needed for safe and adequate treatment of REAHs that have an abundant blood flow.

Endoscopic Modified Medial Maxillectomy for Fungal Ball of the Hypoplastic Maxillary Sinus With Bony Hypertrophy.

Sinus fungal ball is defined as noninvasive chronic rhino-sinusitis with a clump of mold in the paranasal sinuses, typically affecting the maxillary sinus. Fairly good outcomes of endoscopic surgery have been reported where the ball is removed through the antrostomy. However, the affected sinus tends to have a smaller cavity and thicker bony walls. As such, it is often challenging to maintain a window size that is sufficient to control possible recurrence. The endoscopic modified medial maxillectomy procedure was applied to a 61-year old and a 70-year old female patient with maxillary sinus fungal ball. Using this method, we created a much larger inferior meatal antrostomy without difficulty. The window provided us with an endoscopic view of the whole sinus and complete eradication of the lesion. Endoscopic modified medial maxillectomy is useful as a surgical procedure for maxillary sinus fungal ball and should be considered for better outcomes.