Background The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, has resulted in considerable morbidity and mortality in humans. Little is known regarding the development of immunological memory following SARS-CoV-2 infection or whether immunological memory can provide long-lasting protection against reinfection. Urgent need for vaccines is a considerable issue for all governments worldwide. Methods A total of 39 patients were recruited in this study. Tonsillar mononuclear cells (MNCs) were co-cultured in RPMI medium and stimulated with the full-length SARS-CoV-2 spike protein in the presence and absence of a CpG-DNA adjuvant. An enzyme-linked immunosorbent assay (ELISA) was utilised to measure the specific antibody response to the spike protein in the cell culture supernatants. Results The SARS-CoV-2 spike protein primed a potent memory B cell-mediated immune response in nasal-associated lymphoid tissue (NALT) from patients previously infected with the virus. Additionally, spike protein combined with the CpG-DNA adjuvant induced a significantly increased level of specific anti-spike protein IgG antibody compared with the spike protein alone ( p < 0.0001, n = 24). We also showed a strong positive correlation between the specific anti-spike protein IgG antibody level in a serum samples and that produced by MNCs derived from the same COVID-19-recovered patients following stimulation ( r = 0.76, p = 0.0002, n = 24). Conclusion Individuals with serological evidence of previous SARS-CoV-2 exposure showed a significant anti-spike protein-specific memory humoral immune response to the viral spike protein upon stimulation. Additionally, our results demonstrated the functional response of NALT-derived MNCs to the viral spike protein. CpG-DNA adjuvant combined with spike protein induced significantly stronger humoral immune responses than the spike protein alone. These data indicate that the S protein antigen combined with CpG-DNA adjuvant could be used as a future vaccine candidate.

No abstract

Oroantral fistula (OAF) is a pathologic communication between the oral cavity and the maxillary sinus. It is usually associated with maxillary sinusitis, where drainage of sinus infection is a mandatory step during closure of the fistula. The flap used for closure of OAF should be tension free, broadly based and well vascularized. The aim of this study was to assess the effectiveness of closure of OAF using buccal fat pad (BFP) flap with concomitant endoscopic middle meatal antrostomy for maxillary sinus drainage. Nineteen patients with chronic OAF were included in the study. Closure was performed using BFP with endoscopic middle meatal antrostomy. Preoperative and postoperative assessments were carried out. Patients were followed up for at least 1 year postoperatively. Complete closure of all OAFs was achieved with no recurrence or dehiscence. In conclusion, closure of OAF with BFP flap and concomitant endoscopic drainage of the maxillary sinus through the middle meatus is an effective, easy, and simple method. It has a high success rate with no effect on the vestibular depth or mouth opening.

Objectives Pulmonary complications, such as atelectasis, pulmonary oedema, pleural effusion, bronchospasm, and pneumonia, have been reported following cardiac surgery. Shallow breathing leading to impaired lung function is the major cause of respiratory complications. Decreases in respiratory muscle strength can be measured using the maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) produced in the oral cavity. This study aimed to determine the decrease in respiratory muscle strength 8 weeks following cardiac surgery. Moreover, the relationship between lung function and respiratory muscle strength was studied. Methods In this observational study, 42 adult cardiac surgery patients (10 women, 32 men; mean age 65 ± 7 years) were investigated. Lung function and respiratory muscle strength were measured preoperatively and at 2 months postoperatively. Results The pre- and postoperative respiratory muscle strengths were in accordance with the predicted values. The MIP was 81.75 ± 22.04 cmH 2 O preoperatively and 74.56 ± 18.86 cmH 2 O at the 2-month follow-up (p = 0.146). The MEP was 98.55 ± 22.24 cmH 2 O preoperatively and 88.86 ± 18.14 cmH 2 O at the 2-month follow-up (p = 0.19). The preoperative lung function was in accordance with the predicted values; however, lung function significantly decreased postoperatively. At the 2-month follow-up, there was a moderate correlation between the MIP and forced expiratory volume ( r = 0.59, p = 0 .0078). Conclusions The respiratory muscle strength was not impeded either before or 2 months after cardiac surgery. However, the exact mechanism for the alteration in lung function remains unclear. Measures to re-establish the ideal postoperative lung capacity should concentrate on different perioperative pulmonary exercises.

Hearing loss in children with infantile BS is congenital and profound but not related to inner ear malformations. Although cochlear implantation results in certain benefits, general health status and delayed referral to cochlear implant centers have a negative impact on speech perception and development.