Impact of COVID-19 on Taste and Smell Sensation among Population in Western Region of Saudi Arabia

Background: COVID-19 is pandemic disease caused by (SARS-CoV-2) first discovered in China in December 2019. It affects smell and taste sensation among large proportion of patients with COVID-19. The aims of this study is to asses impact of COVID-19 on smell and taste sensation among COVID-19 patients in western region of Saudi Arabia. Methods: The study design was descriptive cross sectional and our sample was be is 500 patients with COVID-19. The data was collected by using structured questionnaire which was distributed electronically and contain (sociodemographic data, diagnosed with COVID-19, status of smell and taste sensation…). The data was analyzed using SPSS program version 22. Results: We were able to collect 404 responses to our questionnaire with response rate of 80.8 %. The mean age of total sample was 32.1 years with standard deviation of 14.34 years and 56.1 % of participants were females. Prevalence of weak or loss of smell or taste after infection with the emerging corona virus was 74.4%. Moreover, we found that patients who had weak or loss of smell or taste because of COVID-19 were older than those whose sense did not be affected. Moreover, non- Saudi Arabian were more affected by losing of smell and taste with significant difference (P=0.026). Considering medical conditions of patients, we found that patients with any medical conditions were associated with significantly higher incidence of losing smell and taste. Conclusion: The prevalence of losing smell and taste among patients with COVID-19 in our sample were high and was higher in older patients, male, Saudi arabian and those with other medical conditions. More investigations should be conducted to assess the same variables using retrospective study design.

EVALUATION OF THE ORAL SYMPTOMS IN COVID 19 PATIENTS IN KAMRUP METRO- A CROSS-SECTIONAL STUDY

The novel coronavirus are found to affect the ACE2 receptors in the epithelial cells of the lining of the respiratory tract. Since live virus have been found in the saliva of infected patients, and ACE2 receptors are present in epithelial lining of salivary glands and tongue, there are chances that the virus might affect the oral cavity and hence might have oral manifestation. The aim of the study was to determine and evaluate the presence of oral symptoms in the patients infected with the 2019 Novel Coronavirus (Covid 19). In this cross sectional descriptive study, a set of questionnaires was MATERIALS AND METHODS: formulated and the patients who have come to covid screening centers in Kamrup Metro region were interviewed for both oral symptoms and general symptoms. A total of 467 patients were evaluated. The samples were divided according to covid positive or negative. Group 1: Covid positive (+ve); Group 2: Covid negative (- ve). Out of which Group 1 had 287 patients whereas Group 2 had 180 patients. Upon statist RESULTS: ical analysis, signicant differences were found with respect to fever, cough, breathing difficulty, sore throat, arthralgia, and asthenia where covid positive patients found to have a high prevalence of these symptoms. On evaluation of the of the oral symptoms in both covid positive and negative patients signicant differences were found viz., burning sensation, swollen gums , changes in taste sensation, pain in the TMJ and bleeding gums with covid positive patients having more predilection of having all these symptoms. On evaluation of the gender predilection between positive patients with symptoms, positive patients without symptoms and negative patients with symptoms , there found to be no signicant difference. oral CONCLUSION symptoms of burning sensation, changes in taste sensation , bleeding gums and pain in the TMJ are found to be more prevalent with patients having corona virus infection.

Anodal Galvanic Taste Stimulation to the Chin Enhances Salty Taste of NaCl Water Solution

Galvanic taste stimulation (GTS) is a non-invasive electrical stimulation of sensory nerves that induces, inhibits, and enhances taste sensation. It has been shown that the cathodal GTS taste enhancement effect occurs when only cathodal electrodes are attached in or near the mouth, while anodal GTS, whose anodal electrodes are attached in or near the mouth, induces an electrical taste sensation rather than taste enhancement. In the present study, we focused on the taste enhancement effect of anodal GTS, enhancing the salty taste produced by a sodium chloride (NaCl) aqueous solution during stimulation. In this study, GTS was applied to the chin rather than the inner mouth so as not to disturb natural eating and drinking behavior, according to a previous study. To demonstrate and quantitatively evaluate its enhancement effect, we conducted two psychophysical experiments in which subjects were asked to indicate the intensity of the saltiness perceived during electrical stimulation by adjusting the concentration of aqueous NaCl to achieve a solution of equivalent saltiness. We discovered that the perceived intensity increased as the current intensity applied to the chin increased. Moreover, the magnification ratios against the baseline exceeded 1 under all conditions of the NaCl aqueous solution. These results indicate that anodal GTS is effective in enhancing the salty taste of NaCl aqueous solutions.

TMC4 is a novel chloride channel involved in high-concentration salt taste sensation

Abstract“Salty taste” sensation is evoked when sodium and chloride ions are present together in the oral cavity. The presence of an epithelial cation channel that receives Na+ has previously been reported. However, no molecular entity involving Cl− receptors has been elucidated. We report the strong expression of transmembrane channel-like 4 (TMC4) in the circumvallate and foliate papillae projected to the glossopharyngeal nerve, mediating a high-concentration of NaCl. Electrophysiological analysis using HEK293T cells revealed that TMC4 was a voltage-dependent Cl− channel and the consequent currents were completely inhibited by NPPB, an anion channel blocker. TMC4 allowed permeation of organic anions including gluconate, but their current amplitudes at positive potentials were less than that of Cl−. Tmc4-deficient mice showed significantly weaker glossopharyngeal nerve response to high-concentration of NaCl than the wild-type littermates. These results indicated that TMC4 is a novel chloride channel that responds to high-concentration of NaCl.

Qualitative Recognition of Primary Taste Sensation Based on Surface Electromyography

Based on surface electromyography (sEMG), a novel recognition method to distinguish six types of human primary taste sensations was developed, and the recognition accuracy was 74.46%. The sEMG signals were acquired under the stimuli of no taste substance, distilled vinegar, white granulated sugar, instant coffee powder, refined salt, and Ajinomoto. Then, signals were preprocessed with the following steps: sample augments, removal of trend items, high-pass filter, and adaptive power frequency notch. Signals were classified with random forest and the classifier gave a five-fold cross-validation accuracy of 74.46%, which manifested the feasibility of the recognition task. To further improve the model performance, we explored the impact of feature dimension, electrode distribution, and subject diversity. Accordingly, we provided an optimized feature combination that reduced the number of feature types from 21 to 4, a preferable selection of electrode positions that reduced the number of channels from 6 to 4, and an analysis of the relation between subject diversity and model performance. This study provides guidance for further research on taste sensation recognition with sEMG.

Molecular and cellular basis of acid taste sensation in Drosophila

Acid taste, evoked mainly by protons (H+), is a core taste modality for many organisms. The hedonic valence of acid taste is bidirectional: animals prefer slightly but avoid highly acidic foods. However, how animals discriminate low from high acidity remains poorly understood. To explore the taste perception of acid, we use the fruit fly as a model organism. We find that flies employ two competing taste sensory pathways to detect low and high acidity, and the relative degree of activation of each determines either attractive or aversive responses. Moreover, we establish one member of the fly Otopetrin family, Otopetrin-like a (OtopLa), as a proton channel dedicated to the gustatory detection of acid. OtopLa defines a unique subset of gustatory receptor neurons and is selectively required for attractive rather than aversive taste responses. Loss of otopla causes flies to reject normally attractive low-acid foods. Therefore, the identification of OtopLa as a low-acid sensor firmly supports our competition model of acid taste sensation. Altogether, we have discovered a binary acid-sensing mechanism that may be evolutionarily conserved between insects and mammals.

PHYTOPHARMACOLOGICAL REVIEW OF KNEMA ATTENUATA (HOOK F. AND THOMSON) WARB

Knema attenuata, a member of Myristicaceae family and commonly known to world as ‘wild nutmeg’ is broadly used in folk medicine for treating ailments such as jaundice, chronic fever, inflammations, spleen disorders, breathing disorders and impaired taste sensation. This review article aims to compile all the updated information on the phytochemical and pharmacological activities of plant Knema attenuata. Studies indicate that different parts such as aril, seed and stem bark of the plant is rich in phenolics, flavonoids, tannins, steroids, terpenes, resins and glycolipids. Moreover, stem bark of Knema attenuata contains a lignan ‘attenuol’ with diverse pharmacological activities. In addition, different extracts of plant parts have been found to possess various pharmacological activities such as antioxidant, antifungal, larvicidal, analgesic, anti-inflammatory, antihyperlipidemic, and hepatoprotective activities. More research on phytochemical composition and therapeutic implications are recommended.

Ribosome protein mutant cells rely on the GR64 cluster of gustatory receptors for survival and proteostasis in Drosophila

Mutations in ribosome protein (Rp) genes and ribosome biogenesis factors result in debilitating diseases, known as ribosomopathies. Recent studies in Drosophila have shown that cells heterozygous mutant for Rp genes (Rp/+) exhibit proteotoxic stress and aggregates, which drive stress pathway activation and apoptosis. Understanding how Rp/+ cells fend off proteotoxic stress could suggest mechanisms to ameliorate these and other conditions caused by proteotoxic stress. Here we find that Rp/+ epithelial cells express all six Gustatory Receptor 64 (Gr64) genes, a cluster of sugar receptors involved in taste sensation. We show that Rp/+ cells depend on Gr64 for survival and that loss of Gr64 autonomously exacerbates stress pathway activation and proteotoxic stress by negatively effecting autophagy and proteasome function in Rp/+ cells. This work identifies a non-canonical role in proteostasis maintenance for a family of gustatory receptors known for their function in neuronal sensation.