• Journal of Rhinology
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• v.60 no.3
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• pp.200-206
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• 2022

Background: Little is known about the occurrence of gustatory dysfunction (GD) in relation to different aetiologies of olfactory dysfunction (OD) as assessed by psychophysical chemosensory tests. The aim of this study was to analyse gustatory function in patients with OD and to investigate clinical factors associated with GD. Methods: A total of 742 individuals who underwent both olfactory and gustatory function tests at a tertiary medical centre from November 2019 to March 2021 were retrospectively enrolled. Olfactory and gustatory function were assessed by the YSK olfactory and gustatory function tests, respectively. Patients with OD were classified into four groups according to the aetiology: sinonasal disease, post-infection OD (PIOD), post-traumatic OD (PTOD), and others. Secondary outcomes included age, sex, smoking history, and alcohol history. Results: Among the 488 patients with OD, 93 (19.1%) showed GD and 395 (80.9%) had normal gustatory function. Only 25 (9.8%) among 254 individuals with normosmia showed GD. Analyses of these frequencies revealed a significant association between OD and GD. In addition, the taste score was significantly lower in patients with OD than individuals with normosmia. The frequency of GD was significantly higher in patients with PTOD (53.6%) than in those with OD of other aetiologies (sinonasal disease, 6.7%; PIOD, 13.0%; others, 24.4%). In the multivariate analysis, age ≥55 years and PTOD were associated with a high frequency of GD among patients with OD. Conclusions: The current study show that GD is significantly associated with OD. In particular, GD is more common in patients with PTOD than in those with OD of other aetiologies.

• Journal of Oral Medicine and Pain
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• v.44 no.3
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• pp.103-111
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• 2019

Purpose: Patients with taste complaints presenting with various abnormal perceptions and alterations in gustatory function are often encountered in dental clinics. Since taste perception is thought to be influenced by numerous factors including neurological and psychological factors, the gustatory profiles of patients complaining of taste abnormalities should be very different. However, the gustatory profiles based on the clinical subtypes of taste complaints have not been fully studied. This study aimed to better understand the gustatory profiles depending on the clinical subtypes of taste complaints. Methods: Clinical data from 169 patients with complaints of altered taste were retrospectively collected to analyse their clinical and gustatory profiles. These complaints were subdivided into hypergeusia, hypogeusia, and dysgeusia for each taste quality according to the clinical types of these complaints. The gustatory profiles were then established by analysing the detection and recognition thresholds for each taste quality depending on the clinical subtypes of taste complaints. Results: Clinical analysis revealed that patients with taste complaints had widely diverse clinical profiles. There were significant differences between males and females with taste complaints in the prevalence rates of symptoms like dry mouth, tongue coating, and burning sensation. While hypogeusia (76.3%) was the most frequent type of taste complaint, it was revealed that the taste thresholds were not always consistent with the patient's description of gustatory symptoms. Conclusions: Patients with taste complaints exhibited diverse clinical profiles with sex differences. Considering the diversity of the taste complaints, the quantitative gustatory testing methods can be valuable to differentially evaluate the presence and intensity of altered taste in patients with these complaints.

• Journal of Oral Medicine and Pain
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• v.39 no.1
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• pp.10-14
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• 2014

Purpose: The aim of this study is to evaluate the difference between gustatory functions in a sleep disordered breathing (SDB) group and a control group. The pathogenesis of SDB has not been fully understood. Though the precise contributions of neuromuscular and anatomical factors on SDB pathogenesis are still debated, we hypothesized that the gustatory dysfunction could be predisposed to SDB. Methods: All patients were diagnosed as SDB by polysomnography (PSG). On the basis of PSG results, patients were divided into 3 groups: snoring, mixed, and obstructive sleep apnea (OSA). The control group comprised healthy volunteers who were the same age as those of the SDB group and whose breathing was verified as normal using a portable sleep monitor device. The patient group and the control group were evaluated for gustatory functions with an electrogustometry (EGM). The electrical taste thresholds were measured in the anterior, midlateral, and posterior sides of the tongue and soft palatal regions, both sides. To find out the difference in EGM scores, statistical analysis was performed using the Kruskal-wallis and Mann-Whitney U test with 95% confidence interval and p<0.05 significance level. Results: The patients with SDB had higher EGM scores than the control group at all spots tested, except for the right midlateral of the tongue, and there was a statistical significance in the comparison between the control group and the divided SDB groups, respectively. Among the divided SDB groups, the snoring group had the most significant differences in the number of the measured spots, but there was no difference among the snoring, mixed, and OSA groups. Conclusions: These results may suggest that neurologic alterations with sleep disordered breathing could be associated with gustatory dysfunction. In the future, further systemic studies will be needed to confirm this study.

• Molecules and Cells
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• v.40 no.5
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• pp.331-338
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• 2017

Regulation of feeding is essential for animal survival. The pharyngeal sense organs can act as a second checkpoint of food quality, due to their position between external taste organs such as the labellum which initially assess food quality, and the digestive tract. Growing evidence provides support that the pharyngeal sensory neurons regulate feeding, but much is still unknown. We found that a pair of gustatory receptor neurons in the LSO, a Drosophila adult pharyngeal organ which expresses four gustatory receptors, is involved in feeding inhibition in response to high concentrations of sodium ions. RNAi experiments and mutant analysis showed that the gustatory receptor Gr2a is necessary for this process. This feeding preference determined by whether a food source is perceived as appetizing or not is influenced by nutritional conditions, such that when the animal is hungry, the need for energy dominates over how appealing the food source is. Our results provide experimental evidence that factors involved in feeding function in a context-dependent manner.

• Molecules and Cells
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• v.46 no.7
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• pp.451-460
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• 2023

Animals generally prefer nutrients and avoid toxic and harmful chemicals. Recent behavioral and physiological studies have identified that sweet-sensing gustatory receptor neurons (GRNs) in Drosophila melanogaster mediate appetitive behaviors toward fatty acids. Sweet-sensing GRN activation requires the function of the ionotropic receptors IR25a, IR56d, and IR76b, as well as the gustatory receptor GR64e. However, we reveal that hexanoic acid (HA) is toxic rather than nutritious to D. melanogaster. HA is one of the major components of the fruit Morinda citrifolia (noni). Thus, we analyzed the gustatory responses to one of major noni fatty acids, HA, via electrophysiology and proboscis extension response (PER) assay. Electrophysiological tests show this is reminiscent of arginine-mediated neuronal responses. Here, we determined that a low concentration of HA induced attraction, which was mediated by sweet-sensing GRNs, and a high concentration of HA induced aversion, which was mediated by bitter-sensing GRNs. We also demonstrated that a low concentration of HA elicits attraction mainly mediated by GR64d and IR56d expressed by sweet-sensing GRNs, but a high concentration of HA activates three gustatory receptors (GR32a, GR33a, and GR66a) expressed by bitter-sensing GRNs. The mechanism of sensing HA is biphasic in a dose dependent manner. Furthermore, HA inhibit sugar-mediated activation like other bitter compounds. Taken together, we discovered a binary HA-sensing mechanism that may be evolutionarily meaningful in the foraging niche of insects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.384-387
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• 2009

Tumors of the deep lobe of parotid gland are rare. These benign tumors have usually been treated by total parotidectomy, which has functional and esthetic side effects. Recently, there has been a trend for operations of parotid gland benign tumors to be less radical and selective deep lobe parotidectomy has been introduced. This technique preserves the superficial lobe and facial nerve when tumor is located in the deep lobe. Selective deep lobe parotidectomy preserves parotid salivary function, minimizes the incidence of facial nerve damage and gustatory sweating (Frey's syndrome) and improves cosmetic outcome. We report a case of pleomorphic adenoma of the deep lobe that was successfully treated by selective deep lobe parotidectomy with satisfactory result.

• Molecules and Cells
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• v.40 no.10
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• pp.731-736
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• 2017

Taste sensitivity to sugars plays an essential role in the initiation of feeding behavior. In Drosophila melanogaster, recent studies have identified several gustatory receptor (Gr) genes required for sensing sweet compounds. However, it is as yet undetermined how these GRs function as taste receptors tuned to a wide range of sugars. Among sugars, fructose has been suggested to be detected by a distinct receptor from other sugars. While GR43A has been reported to sense fructose in the brain, it is not expressed in labellar gustatory receptor neurons that show taste response to fructose. In contrast, the Gr64a-Gr64f gene cluster was recently shown to be associated with fructose sensitivity. Here we sought to decipher the genes required for fructose response among Gr64a-Gr64f genes. Unexpectedly, the qPCR analyses for these genes show that labellar expression levels of Gr64d and Gr64e are higher in fructose low-sensitivity flies than in high-sensitivity flies. Moreover, gustatory nerve responses to fructose in labellar sensilla are higher in Gr64d and Gr64f mutant lines than in mutant flies of the other Gr64a-Gr64f genes. These data suggest the possibility that deletion of GR64D or GR64F may indirectly induce enhanced fructose sensitivity in the labellum. Finally, we conclude that response to fructose cannot be explained by a single one of the Gr64a-Gr64f genes.

• Animal cells and systems
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• v.15 no.1
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• pp.53-61
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• 2011

The fine structural characteristics of the antennal sensory organs of a female millipede Oxidus gracilis (Polydesmida: Paradoxomatidae) were observed with both field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). We could identify four apical cones and three basic types of antennal sensillae in a. gracilis as follows: chaetiform sensilla (CS), trichoid sensilla (TS) and basiconic sensilla (BS). Of these, both types of CS and TS can be observed throughout all antennal segments except the terminal 8th article, whereas the BS are observed within the cuticular depressed regions of the articles from the 5th to the 7th segment. According to their relative microstructure and location, the BS arc divided further into three subtypes: large ($BS_1$) small ($BS_2$) and spiniform ($BS_3$). The $BS_1$ can be seen on the 5th article only, while $BS_2$ can be seen on the 5th and 6th articles. The $BS_3$ is characteristically seen within the depressive region of the 7th article. Both the CS and TS of O. gracilis are similar in structure, and they are related to the function of mechanical reception; however, four large apical cones (AP) and three subtypes of BS are likely to function in gustatory and olfactory reception.

• Journal of Oral Medicine and Pain
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• v.35 no.3
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• pp.183-192
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• 2010

The aim of this study is to determine a relationship between the smoking and the gustation. For that purpose, the survey is about the subjective taste change after smoking compared the electrical taste thresholds by EGM on healthy young Korean men before and after smoking. The results of the electrogustometry showed significant differences between smokers and non-smokers, also between before smoking and directly after smoking in smokers showed significant differences which indicated the immediate, but temporary effects of smoking on the taste thresholds. There were no difference of gustatory function by the amount of smoking and the degree of addiction. Based on the results of this study, further studies will be focused on the difference of gustatory function between before and after smoking using the chemical taste test, and the relationship between change of olfactory and gustation by smoking.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.60.1-60.6
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• 2019

Background: The lingual nerve plays an important role in multiple functions, including gustatory sensation and contact sensitivity and thermosensitivity. Misdiagnosed conservative treatments for serious lingual nerve (LN) injuries can induce the patient to serious mental disability. After continuous observation and critical diagnosis of the injury, in cases involving significant disruption of lingual nerve function, microneurosurgical reconstruction of the nerve is recommended. Direct anastomosis of the torn nerve ends without tension is the recommended approach. However, in cases that present significant gaps between the injured nerve ends, nerve grafts or conduits (tubes of various materials) are employed. Recently, various reconstruction materials for peripheral nerves were commercially offered especially in the USA, but the best method and material is still unclear in the world. There currently exists no conventional protocol for managing LN neurosensory deficiency in regard to optimal methods and the timing for surgical repair. In Japan, the allograft collagen nerve for peripheral nerves reconstruction was permitted in 2017, and we tried to use this allograft nerve and got a recommendable result. Case presentation: This report is a long-term abandoned torn LN reconstructed with allograft nerve induced by the lower third molar extraction. Conclusions: In early sick period, with the exact diagnosis, the LN disturbance should be managed. In a serious condition, the reconstruction with allograft nerve is one of the recommendable methods.