Background: COVID-19 developed a sudden onset of smelling disorders. Researchers used self-reported or special tests to study this issue. We aimed to investigate whether quantitative-test smell disorders have a considerable difference from self-reported or not. Methods: We searched 554 studies published between December 2019 to September 2020 by the PICO model. Our search strategies were based on MeSH terms in the electronic databases Web of Science (136 articles), Scopus (84 articles), and PubMed (334 articles). The duplicated articles were excluded, then the preferred reporting items for systematic reviews and meta-analysis guidance were utilized. Finally, we divided the studies into two (self-report (33 articles) and specific-test (9 articles)) groups. Results: 33 (80%) articles expressed olfactory dysfunction by self-report of patients and 9(20%) studies were conducted by a specific test. Only three studies, one in self-report; ((internal reliability, Cronbach α = 0.84) and validity (r = –0.60, p < 0.001)) and two in specific-test groups; ((test-retest r=0.94) and another study (test-retest r >0.7)) conducted validity and reliability. Self-reported studies published a various range of prevalence (20% _97%) in patients with COVID-19. COVID-19 patients with a specific-test group were found to have a primary incidence of anosmia of over 65%, even reaching 98% depending on the types of tests. Conclusion: Self-reporting of COVID-19 detection can be affected by sociodemographic factors. Although self-reported questionnaires are economical and easy to use, standardized tests provide more reliable comparisons and professional assessments. Therefore, standardized tests are recommended for more accurate screening over self-reporting.

olfactory imprinting is one of the affordable approaches for improving neonatal feeding in husbandry. In order to evaluate the possibility of olfactory imprinting in the Persian sturgeon larvae and to evaluate its future application in the feeding of larvae, two groups of early fertilized eggs were exposed to the stimuli solution (phenyl ethyl alcohol (0. 0001 mol/L) and the fish feed extract (0. 01 g/L) until 29 days after hatching. The third group (control) exposed to neither stimuli solution nor the fish feed extract. Fish larvae behavior was examined in Ymaze at days 11 and 25 posthatch in order to evaluate the larvae preference/avoidance reactions to the stimuli solution and the fish feed extract. The results indicated that the exposed Persian sturgeon larvae did not show any preference/avoidance reaction at day 11 posthatch to the pertinent stimuli, whereas the exposed Persian sturgeon larvae preference was for the stimuli solution rather than the fish feed extract at day 25 posthatch (P<0. 05). The preference of larvae of the control group was for the fish feed extract rather than the stimuli solution at day 25 posthatch, whereas the exposed Persian sturgeon larvae preference was for the stimuli solution rather than the fish feed extract at day 25 posthatch. The average time of the larvae presence (value for reaction) in the arm containing the pertinent stimuli was significantly higher than the average time of the larvae presence in the arm containing the fish feed extract (P<0. 05). The result indicated that continues exposure of egg and larvae of the Persian sturgeon to the phenyl ethyl alcohol (0. 0001 mol/L) and the fish feed extract (0. 01 g/L) could change olfactory preference of the larvae at day 25 posthatch.

Objective: Many people over the world lose the hearing and turn deaf. One of the greatest challenges in the treatment of inner ear disorders is to find a cure for the hearing loss which is caused by the loss of inner ear cochlear hair cells or spiral ganglion neurons. So stem cell resources which are capable of differentiating into hair cells are necessary. Many studies aimed to differentiate stem cells to hair cell for example using embryonic stem cells and adult stem cells like neural stem cells. But using this type of stem cells have some problem for example embryonic stem cells have great potential to differentiate into hair cells, but they also have tumorigenic potential when transplanted or Neural stem cells do not differentiate to hair cells completely and not in a high amount. Rat olfactory mocusa contains stem cell population that can be cultured as a neurospheres and have multipotency to differentiate to different cell types. In this study we differentiated olfactory stem cells into functional inner ear hair cells.Materials and Methods: Rat olfactory epitheliums were isolated and cultured in proliferation medium after enzymatic digestion and cell isolation. To induce inner ear hair cells differentiation, the cells were cultured in differentiation medium after fifth passage. For characterization of the hair cells RT-PCR for three specific gene was done, include: Brn 3.1, Math 1, Myosin IIV, and immunocytochemistry assays were used for some specific markers such as: P27 (DCS-72, SPM 348), Myosin VIIa (C-5, A-16), MATH-1 (Y-23, N-19). Morphological properties were also considered.Results: Hair cells differentiation was confirmed by expression of multiple genes related to this type of cells by RT-PCR and also differentiation was assessed by immunoflorescence staining using specific antibodies. Hair cells were also confirmed by their morphologic characterization.Conclusion: Our results demonstrated that olfactory stem cells obtained from olfactory epithelium of rat has a differentiation potential to produce hair cells of inner ear in vitro therefore it can provide a potential source of autologous cells for transplantation.

Background: The number of patients with COVID-19-induced olfactory dysfunction has consistently increased since the onset of the pandemic. Since a considerable proportion of these patients have olfactory dysfunction for a relatively long period of time, their quality of life (QOL) may considerably be impacted as a result. Aim: The aim of the present study was to investigate the adverse effects of olfactory dysfunction on QOL in patients with COVID-19-induced hyposmia or anosmia. Methods: The data were obtained via self-reported online questionnaire in individuals who met the inclusion criteria. The questionnaire included demographics, olfactory status and Questionnaire of olfactory Disorders-Negative Statements (QOD-NS). Results: Among1531 participants, 1072 individuals met the inclusion criteria, with 588 (54. 85%) having hyposmia and 484 (45. 15%) anosmia. Average age was 35. 7 in the hyposmic group and 34. 5 in the anosmic group. Concurrent hypogeusia/ageusia was reported in 398 (67. 7%) of cases with hyposmia and in 346 (71. 5%) of participants with anosmia. Lack of enjoyment of eating food was the most negative effect in both hyposmic and anosmic groups, followed by annoyance when eating food and a continuous awareness of the olfactory problem. The mean QOD-NS score was 20. 5±, 10. 2 in the hyposmic group and 23. 3±, 10. 4 in the anosmic group, demonstrating significant adverse impact on QOL. Conclusion: Persistent olfactory dysfunction in patients with COVID-19 has adverse effects on QOL. Early diagnosis and treatment of olfactory dysfunction may be crucial in limiting the adverse impact on QOL by psychological and nutritional support and olfactory rehabilitation.

olfactory ensheathing cells-based therapy for spinal cord injury (SCI) repair has been a possible treatment for clinical study because of their safety in autologous transplantation and potential regenerative capability. However, there are contradictory reports on the results after transplantation in animal models. The purpose of this research was to investigate the effect of acute transplantation of human mucosa-derived olfactory ensheathing cells (OECs) on the repair of the spinal cord. Human olfactory ensheathing cells were isolated from the human mucosa and cultured under supplemented neuronal cell culture medium. They were characterized by immunocytochemistry for olfactory ensheathing cell markers. We induced spinal cord injury at T8-T9 of rats by aneurysm clips and simultaneously injected two million OECs into subarachnoid space of spinal cord. Sensory and motor behaviors were recorded by tail-flick reflex (TFR) and BBB scores, respectively every week for seven weeks after injury. Morphology and S100-beta antigen expression in olfactory ensheathing cells of the human olfactory mucosa was confirmed by immunostaining. OECs transplantation did not recover inflammation, neuronal vacuolation, hemorrhage, and cyst formation. These findings suggest that OECs transplantation in this experimental setting did not lead to tissue regeneration to enhance locomotion. These results broaden current knowledge and are additions to the science and literature.

olfactory dysfunction is a known complication of diabetes and, despite its importance in the quality of life, is usually neglected due to its gradual progression. In this study, we aim to determine the prevalence and severity of olfactory dysfunction in diabetics and its association with microangiopathic complications of the disease (neuropathy, nephropathy, and retinopathy). Excluding the confounding factors, a case-control study of 60 eligible subjects, divided into a group of 30 diabetic patients and a group of 30 control subjects was performed. We used “absorbent perfumer's paper strips” method to test the olfactory threshold. In our study, 60% of diabetics were found to have some degree of olfactory dysfunction and a significant difference (P<0.01) between the olfactory threshold of the case and control groups was observed. There were no significant associations between the olfactory dysfunction and age, sex, treatment duration and microangiopathic complications.