Behavioural insights and attitudes on community masking during the initial spread of COVID-19 in Hong Kong.

INTRODUCTION: Community face mask use during the coronavirus disease 2019 (COVID-19) pandemic has considerably differed worldwide. Generally, Asians are more inclined to wear face masks during disease outbreaks. Hong Kong has emerged relatively unscathed during the initial outbreak of COVID-19, despite its dense population. Previous infectious disease outbreaks influenced the local masking behaviour and response to public health measures. Thus, local behavioural insights are important for the successful implementation of infection control measures. This study explored the behaviour and attitudes of wearing face masks in the community during the initial spread of COVID-19 in Hong Kong. METHODS: We observed the masking behaviour of 10 211 pedestrians in several regions across Hong Kong from 1 to 29 February 2020. We supplemented the data with an online survey of 3199 respondents' views on face mask use. RESULTS: Among pedestrians, the masking rate was 94.8%; 83.7% wore disposable surgical masks. However, 13.0% wore surgical masks incorrectly with 42.5% worn too low, exposing the nostrils or mouth; 35.5% worn 'inside-out' or 'upside-down'. Most online respondents believed in the efficacy of wearing face mask for protection (94.6%) and prevention of community spread (96.6%). Surprisingly, 78.9% reused their mask; more respondents obtained information from social media (65.9%) than from government websites (23.2%). CONCLUSIONS: In Hong Kong, members of the population are motivated to wear masks and believe in the effectiveness of face masks against disease spread. However, a high mask reuse rate and errors in masking techniques were observed. Information on government websites should be enhanced and their accessibility should be improved.

Horizontal root fractures in posterior teeth without dental trauma: tooth/root distribution and clinical characteristics.

AIM: To describe the clinical characteristics and radiographic findings of horizontal root fractures (HRF) in posterior teeth without a history of dental trauma. METHODOLOGY: A total 24 patients and 31 HRF cases in 28 posterior teeth were collected from 2006 to 2015. Clinical examinations and radiographic imaging were evaluated. Value of confidence intervals of the proportions was calculated for data presentation. RESULTS: The number of males (54%) was similar to females (46%). The patients were predominantly between 50 and 70 years of age (75%). Most HRF cases were found in nonendodontically treated teeth (79%), without crown and bridge restorations (82%), and maxillary molars (54%). Many roots of maxillary molars had developed HRF, and the probability was nearly equal. Fractured teeth usually presented with periodontal and apical bone loss, and most patients (92%) were diagnosed with full mouth chronic periodontitis. Tooth wear was another common clinical feature amongst these patients. CONCLUSIONS: HRF in posterior teeth without dental trauma occurred mainly in patients aged between 50 and 70, in nonendodontically treated teeth, teeth with attrition but without crown and bridge restorations, maxillary molars and with periodontal and periapical bony destruction. Periodontal condition, occlusal wear and patients' age at diagnosis were the possible related factors. HRF in posterior teeth without dental trauma is a diagnostic challenge and even misdiagnosed. A thorough clinical examination, radiographic analysis and recognition of the clinical characteristics are helpful in the early diagnosis and treatment of HRF.

How often does the embryo implant at the location to which it was transferred?

OBJECTIVE: To determine how often the embryo implants exactly at the site of transfer and what additional factors may affect the eventual site of implantation in assisted reproductive technology (ART) cycles. METHODS: This was a prospective observational study of women undergoing ART treatment in a tertiary university unit. Several factors inherent to the embryo transfer (ET), such as the location of the air bubbles and uterine contractility at 1 and at 60 min after ET were assessed with two-dimensional and three-dimensional (3D) ultrasound. In women in whom there was a resulting pregnancy, the position of the gestational sac (i.e. right, left, center or low) was subsequently assessed using 3D ultrasound, and predictors of its location were evaluated. RESULTS: Of 239 recruited women with visualization of air bubbles at ET, 71 singleton gestational sacs were subsequently observed on 3D ultrasound. Overall, 40.8% (29/71) of embryos implanted at the location where the air bubbles were visualized at 1 min after ET, and 50.7% (36/71) implanted where the air bubbles were visualized at 60 min after ET (Cohen's kappa coefficients 0.21 and 0.37, respectively; comparison of agreement values: P = 0.28). Specifically, at 1 min the correspondence between the location of the air bubble and embryo implantation was 37.5% (6/16), 57.1% (8/14), 36.8% (7/19) and 36.4% (8/22) for right, left, central and lower uterus, respectively (4 × 4 contingency table, P < 0.01); at 60 min, the correspondence was 72.2% (13/18), 50.0% (9/18), 33.3% (8/24) and 85.7% (6/7), respectively (5 × 4 contingency table, P < 0.001). In addition, higher vs lower frequency of uterine contractions at 60 min was associated with different sites of implantation (5.6% (1/18), 11.1% (2/18), 27.8% (5/18) and 55.6% (10/18) vs 34.0% (18/53), 24.5% (13/53), 13.2% (7/53) and 28.3% (15/53) for right, left, central and lower uterus, respectively, P < 0.05). In particular, a high uterine contraction frequency following ET was associated with a twofold increased chance of the pregnancy implanting in the lower part of the uterine cavity (relative risk, 1.96 (95% CI, 1.08-3.56), P < 0.05). CONCLUSIONS: The position of the air bubbles within the first 60 min of ET appears to predict the site of implantation in approximately half of cases, denoting an overall poor agreement. This implies significant embryo migration, and has important clinical implications, as it demonstrates that other factors such as uterine contractility may dictate where the embryo will eventually implant following transfer. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

An unusual cause of acromegaly.

We report a rare case of acromegaly due to a growth hormone releasing hormone-secreting bronchial carcinoid tumour. A 40-year-old man initially presented with acromegalic features, and was subsequently found to have a large lung mass in the right lower zone on chest X-ray. Right lower lobectomy was performed, and the tumour was confirmed to be a bronchial carcinoid tumour on histology. Resection of the tumour led to normalisation of serum insulin-like growth factor 1 level and growth hormone responses to an oral glucose tolerance test.

Butyrate induces reactive oxygen species production and affects cell cycle progression in human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Short-chain fatty acids, such as butyric acid and propionic acid, are metabolic by-products generated by periodontal microflora such as Porphyromonas gingivalis, and contribute to the pathogenesis of periodontitis. However, the effects of butyrate on the biological activities of gingival fibroblasts (GFs) are not well elucidated. MATERIAL AND METHODS: Human GFs were exposed to various concentrations of butyrate (0.5-16 mm) for 24 h. Viable cells that excluded trypan blue were counted. Cell cycle distribution of GFs was analyzed by propidium iodide-staining flow cytometry. Cellular reactive oxygen species (ROS) production was measured by flow cytometry using 2',7'-dichlorofluorescein (DCF). Total RNA and protein lysates were isolated and subjected to RT-PCR using specific primers or to western blotting using specific antibodies, respectively. RESULTS: Butyrate inhibited the growth of GFs, as indicated by a decrease in the number of viable cells. This event was associated with an induction of G0/G1 and G2/M cell cycle arrest by butyrate (4-16 mm) in GFs. However, no marked apoptosis of GFs was noted in this experimental condition. Butyrate (> 2 mm) inhibited the expression of cdc2, cdc25C and cyclinB1 mRNAs and reduced the levels of Cdc2, Cdc25C and cyclinB1 proteins in GFs, as determined using RT-PCR and western blotting, respectively. This toxic effect of butyrate was associated with the production of ROS. CONCLUSION: These results suggest that butyrate generated by periodontal pathogens may be involved in the pathogenesis of periodontal diseases via the induction of ROS production and the impairment of cell growth, cell cycle progression and expression of cell cycle-related genes in GFs. These events are important in the initiation and prolongation of inflammatory processes in periodontal diseases.

Effect of triethylene glycol dimethacrylate on the cytotoxicity, cyclooxygenase-2 expression and prostanoids production in human dental pulp cells.

AIM: To evaluate the effect of TEGDMA on cell cycle progression as well as alterations of cell cycle-related gene and protein expression. METHODOLOGY: Human dental pulp cells were exposed to 0-5 mmol L(-1) TEGDMA for 24 h. Cytotoxicity was evaluated by 3-(4, 5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Cell cycle progression was analysed by propidium iodide (PI) flow cytometry. Cell death pathway was surveyed by annexin V/PI dual-staining flow cytometry. The mRNA expression of cell cycle-related genes (cdc2, cyclinB1 and p21) and COX-2 was evaluated by reverse transcriptase-polymerase chain reaction, and their protein expression was evaluated by Western blotting. The production of PGE(2) and PGF(2α) in the culture medium was determined by enzyme-linked immunosorbent assay. RESULTS: Triethylene glycol dimethacrylate inhibited cellular growth and induced cell cycle deregulation in dental pulp cells. High-dose exposure provoked both necrotic and apoptotic cell death. The gene and protein expression of cdc2, cyclin B1 and cdc25C declined obviously whilst cells treated with 2.5 mmol L(-1) TEGDMA concurrent with the elevated expression of p21. The mRNA and protein expression of COX-2, along with production of PGE(2) and PGF(2α), are drastically raised by 2.5-5 mmol L(-1) TEGDMA. CONCLUSIONS: Triethylene glycol dimethacrylate induced cytotoxicity, cell cycle arrest and apoptosis in dental pulp cells, which was associated with the decline of cdc2, cyclin B1, cdc25C expression and elevation of p21 expression. Concomitantly, COX-2 expression, PGE(2) and PGF(2α) production increased. These effects may contribute to explain the pulpal damage and inflammation induced by TEGDMA after operative procedures.

Adherence of nurses to annual seasonal influenza vaccination over a 5-year period.

BACKGROUND: Healthcare workers (HCWs) are at risk of influenza infection with associated nosocomial transmission. Sustained adherence to seasonal influenza vaccination uptake each year is important in epidemic control. AIM: To assess the adherence of nurses to seasonal influenza vaccination over 5 years and its associated factors. METHODS: A cross-sectional study was conducted among nurses after the winter influenza season in Hong Kong in March 2019. Based on influenza vaccine uptake rates in the 2014/15-2018/19 seasons, respondents were stratified into three groups: 'full adherence' (vaccine uptake in five seasons), 'partial adherence' (vaccine uptake in one to four seasons) and 'non-adherence' (no vaccine uptake). Stepwise multi-variable logistic regression was performed to determine the associations between adherence to annual influenza vaccination, respondents' characteristics and considerations for vaccination. FINDINGS: Of 1306 nurses recruited, the majority were female (88%) with a median age of 36 years (interquartile range 30-46 years). The influenza vaccination uptake rate increased from 36% in the 2014/15 season to 47% in the 2018/19 season. After stratification, 39%, 40% and 21% of respondents were non-adherers, partial adherers and full adherers, respectively. Full adherence was significantly associated with female gender [adjusted odds ratio (aOR) 0.60], age ≥40 years (aOR 2.92), long-term care facility nurse (aOR 0.56), uptake during studentship (aOR 3.83), local prevalence of seasonal influenza (aOR 0.51) and expert opinion (aOR 4.04). CONCLUSIONS: A limited proportion of nurses were fully adherent to seasonal influenza vaccination. Monitoring adherence, improving access to vaccines, and interventions targeting less-adherent HCWs are crucial.

Prostaglandin F(2alpha) stimulates MEK-ERK signalling but decreases the expression of alkaline phosphatase in dental pulp cells.

AIM: To study prostaglandin F(2alpha) (PGF(2alpha)) receptor expression and downstream signalling in cultured human dental pulp cells and the effect of PGF(2alpha) on the alkaline phosphatase (ALP) activity of dental pulp cells. METHODOLOGY: Human dental pulp cells were cultured and exposed to PGF(2alpha). The expression of PGF(2alpha) (FP) receptors was analysed by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. The activation of extracellular regulated kinase (ERK) and cAMP responsive element binding protein/activating transcription factor-1 (CREB/ATF-1) signalling was determined by Western blotting. The expression of ALP in pulp cells after exposure to PGF(2alpha) was evaluated by ALP staining and PCR. RESULTS: Dental pulp cells expressed FP receptor mRNA and protein. Exposure to PGF(2alpha) revealed little cytotoxicity to pulp cells. PGF(2alpha) induced both ERK and CREB/ATF-1 phosphorylation in pulp cells. Exposure to PGF(2alpha) (>1 micromol L(-1)) further decreased the ALP activity and mRNA expression. However, U0126 (an inhibitor of MEK1) showed little preventive effect on the decline of ALP activity in dental pulp cells by PGF(2alpha). CONCLUSION: PGF(2alpha) may potentially activate FP receptors leading to ERK/CREB-ATF-1 activation during its production in inflamed dental pulp. PGF(2alpha) attenuated the ALP activity of pulp cells possibly via pathways not solely by MEK/ERK activation. PGF(2alpha) is a contributing factor of pulpal inflammation by regulating the activities of pulp cells.

Should lidocaine spray be used to ease nasogastric tube insertion? A double-blind, randomised controlled trial.

OBJECTIVE: To investigate the efficacy and safety of lidocaine nasal spray before nasogastric tube insertion in an emergency department. DESIGN: Double-blind, randomised controlled study. SETTING: Emergency department of a major regional hospital in Hong Kong. PATIENTS: A total of 206 adult patients, for whom nasogastric tube insertion was indicated. MAIN OUTCOME MEASURES: Primary outcome was discomfort gauged on a visual analogue scale, and Likert scale addressing difficulty of nasogastric tube insertion. RESULTS: Compared with placebo spray use, lidocaine spray use was associated with less patient discomfort, and less difficulty in nasogastric tube insertion, both difference being statistically significant. CONCLUSION: Intranasal lidocaine spray before nasogastric tube insertion was safe and effective in reducing patient discomfort related to the procedure.

The first novel influenza A (H1N1) fatality despite antiviral treatment and extracorporeal membrane oxygenation in Hong Kong.

We report the first fatality caused by novel influenza A (H1N1) infection despite having the diagnosis confirmed and being given antiviral treatment after hospitalisation. This patient was also the first with influenza A (H1N1) to be supported with extracorporeal membrane oxygenation in Hong Kong. Although extracorporeal membrane oxygenation is an effective means of supporting patients with refractory hypoxaemia on high mechanical ventilatory support, it is labour-intensive and technically demanding. We also discuss the challenges faced when managing this case.

Effects of TGF-beta s on the growth, collagen synthesis and collagen lattice contraction of human dental pulp fibroblasts in vitro.

Transforming growth factor-beta (TGF-beta) is important in regulating the repair and regeneration of damaged dental pulp. For further elucidating the roles of different isoforms of TGF-beta in the healing and inflammatory processes of human dental pulp, we found that TGF-beta1, TGF-beta2 and TGF-beta3 inhibited the growth of two human dental pulp cell strains in vitro by 19-29, 18-25 and 23-26%, respectively, at a concentration of 0.5 ng/ml. TGF-beta also differentially stimulated the collagen synthesis of pulp cells. Collagen synthesis increased by 1 ng/ml of TGF-beta1 and TGF-beta2 by 42 and 51%, respectively. TGF-beta3 (0.1-1 ng/ml) lacked of stimulatory effect on collagen synthesis of pulp cells. Pulp cells have the intrinsic capacity to contract collagen lattice, leading to decreasing of lattice diameter. An 8 h exposure to TGF-beta1 and TGF-beta2 enhanced the pulp cell-populated collagen lattice contraction at concentrations ranging from 0.2 to 3 ng/ml. At similar concentrations, TGF-beta3 lacked of this stimulatory effect. When collagen lattice were detached after 24 h of exposure, TGF-beta1 and TGF-beta2 (0.6-3 ng/ml) induced the pulp cells-populated collagen lattice contraction within 4-8h of gel detachment. These results indicate that TGF-beta-induced collagen lattice contraction is a late cellular event. These in vitro results indicate that effects of TGF-beta isoforms on the growth, collagen synthesis and collagen lattice contraction of pulp cells may play crucial roles in the pathobiological processes of dental pulp.

Evaluation of location and dimensions of mandibular lingual canals: a cone beam computed tomography study.

This retrospective study evaluated the presence, location, and diameter of the mandibular lingual canals in a Taiwanese population using cone beam computed tomography (CBCT), to help improve the safety of mandibular surgical procedures. A total of 101 patients (46 men and 55 women), with a mean age of 55 years, were enrolled. Cross-sectional CBCT images of the mandible were used to define the orifice and diameter of each lingual canal detected. The relevance of all data for both sexes was assessed and analyzed statistically using non-paired t-tests. The canals were categorized as median (MLC) and lateral lingual canals (LLC) based on the position of the mandible. The midline of the symphysis showed the highest frequency of lingual canals (97.0%), and all patients exhibited at least one lingual perforating bone canal in the mandible. The lingual canal diameter ranged from 0.25 to 1.90 mm (mean 0.61 mm) in the midline region and from 0.25 to 1.60mm (mean 0.58 mm) in the lateral region. Significant differences in diameter were observed between the sexes in the MLC and LLC groups (men>women). The results suggest that mandibular lingual vascular canals are common and detected regularly using CBCT.

Recombinant human monoclonal antibody IgG1b12 neutralizes diverse human immunodeficiency virus type 1 primary isolates.

The CD4-binding domain of human immunodeficiency virus type 1 (HIV-1) gp120 elicits antibodies that are present in infected human sera. Monoclonal antibodies that recognize the HIV-1 gp120 CD4-binding domain have been isolated. Some of these antibodies can neutralize laboratory-adapted strains of HIV-1 and probably mediate neutralization by interfering with virus binding to its cellular CD4 receptor. However, most anti-CD4 binding domain antibodies do not neutralize primary HIV-1 isolates. We used primary HIV-1 isolates in an infectivity reduction assay to test the uniquely derived anti-CD4 binding domain recombinant human monoclonal antibody, IgG1b12. All of the tested HIV-1 isolates were neutralized by this antibody. Additional studies indicated that neutralization of a primary isolate with MAb IgG1b12 did not require continuous exposure of human peripheral blood mononuclear cell cultures to the antibody. Finally, a complete IgG1 molecule of an in vitro-selected b12 FAb mutant with a > 400-fold increase in affinity was assembled, expressed in mammalian cells, and evaluated in the infectivity reduction assay in comparative studies with the parent IgG1b12 antibody. The mutant did not retain the level of primary isolate neutralization potency that was a property of the parent molecule. Thus, we confirm that recombinant IgG1b12 has a unique specificity, and that it can neutralize all primary isolates tested in human PBMC cultures in vitro.

Identification of linear surface epitopes on the guinea pig sperm membrane protein PH-20.

The sperm plasma membrane protein PH-20 has previously been shown to be an effective immunogen for protection against fertilization in guinea pigs. To identify immunodominant regions on gpPH-20 that may be related to this contraceptive effect, we used several high-titer immune sera obtained from animals rendered infertile by gpPH-20 injections to screen a set of overlapping peptides that cover the entire 494-residue sequence. Multiple clusters of peptide sequences exhibited specific reactivity. Some of these sequences were then constructed as octameric synthetic peptides and tested for immunogenicity in female guinea pigs. Our results indicated two regions (res. 94-119 and res. 424-444) to be highly immunogenic and both are surface accessible when native gpPH-20 is in solution or anchored on sperm surface. Both anti-peptide antibodies are specific for gpPH-20 and one of them inhibited hyaluronidase activity partially. These monospecific antibodies should be useful probes for further molecular definition of gpPH-20 structure-function relationships.

Characterization of cloned human endothelin receptors.

Two subtypes of human endothelin receptors, ETA and ETB, have been cloned and stably expressed in Chinese Hamster Ovary cells. These receptors have been characterized by [125I]-endothelin-1 binding and phosphatidyl inositol hydrolysis using the potent peptidyl ETA antagonists BQ-123 and BQ-153, as well as the potent ETB agonist, sarafotoxin S6c. In binding studies, Ki values for BQ-123 and BQ-153 are 17 nM and 13 nM for ETA compared to 11,100 nM and 7200 nM for ETB. Conversely, Ki values for sarafotoxin S6c are 2800 nM for ETA and 0.29 nM for ETB. Endothelin-1 stimulates phosphatidyl inositol hydrolysis in cells expressing either ETA or ETB with EC50 values of 0.2-0.3 nM, while sarafotoxin S6c stimulates phosphatidyl inositol hydrolysis only in ETB expressing cells with an EC50 value of 0.2 nM, consistent with the binding data. Comparison of binding data for the cloned and expressed human receptors with binding data for receptors obtained from human tissues indicates the cloned and expressed receptors are essentially indistinguishable from the naturally occurring receptors.

Successful treatment of pulpal-periodontal combined lesion in a birooted maxillary lateral incisor with concomitant palato-radicular groove. A case report.

Palato-radicular groove (PRG) is a common developmental anomaly of maxillary incisors, whereas PRG associated with a birooted maxillary incisor is relatively infrequent. The clinical significance of PRG is related to the incidence of localized periodontitis with or without pulpal pathosis, depending on the depth, extent, and complexity of the groove. Successful treatments of PRG in single-rooted incisors have been reported in the literature. However, treatment of PRG in birooted incisors has often been ineffective. This case report describes a pulpal-periodontal combined lesion occurring on a birooted maxillary left lateral incisor with concomitant PRG in a 13-year-old boy which was successfully treated by conventional endodontic therapy in combination with periodontal treatment including accessory root resection, radiculoplasty and bone grafting. Seven-year follow-up is included in this report. The basis of a successful result is accurate diagnosis and elimination of inflammatory irritants and contributory factors. Awareness of the existence of this abnormality by the clinician is important.

Effects of butyrate and propionate on the adhesion, growth, cell cycle kinetics, and protein synthesis of cultured human gingival fibroblasts.

BACKGROUND: Various periodontal and root canal pathogens, such as the Bacteroides species, can produce significant amounts of short chain fatty acids (SCFA). The roles of SCFA in the pathogenesis of periodontal disease are still not fully understood. METHODS: We therefore investigated 2 main SCFA, butyrate and propionate, on the functional behavior of cultured human gingival fibroblasts (GF) such as cell growth, protein synthesis, cell adhesion capacity, and cell cycle progression. RESULTS: Butyrate and propionate inhibited the growth of healthy (HGF) and inflamed gingival fibroblasts (IGF) in a dose dependent manner. At concentrations of 4, 8, and 16 mM, butyrate suppressed the cell growth by 11 to 58%, 16 to 60%, and 50 to 71%, respectively. The response of cultured gingival fibroblasts to SCFA showed individual differences. Morphologically, GF became larger and more flattened in appearance following exposure to butyrate (>8 mM) and propionate (>24 mM) for 5 days. Inhibitory effects of butyrate (>2 mM) and propionate (>8 mM) on the growth of GF were due possibly to their inhibition of cell-cycle progression. At concentrations of 2 and 8 mM, butyrate led to G0/G1 arrest. Elevation of the exposure concentration to 8 to 24 mM further result in G2/M phase arrest of GF. On the other hand, propionate, at concentrations ranging from 4 to 24 mM, led to G0/G1 arrest. Butyrate (>2 mM) inhibited the proline-rich protein synthesis of GF. At concentrations of 4, 8, 16, and 24 mM, butyrate inhibited the protein synthesis of HGF-1 by 42%, 43%, 51%, and 54%, respectively. In all strains of cultured GF, the suppressive effect of propionate is less than that of butyrate. At concentration range of 4 to 24 mM, propionate suppressed the protein synthesis of HGF-1 by 23 to 43%. However, both butyrate and propionate (4 to 48 mM) exerted little effects on the adhesion of GF to type I collagen within 3 hours of incubation. CONCLUSIONS: These results suggested that SCFA released by pathogenic microorganisms can contribute to the gingival tissue dysfunction and breakdown through their actions on specific biological functions of GF.

Primary extramedullary plasmacytoma in cyclosporine-induced gingival overgrowth. A case report.

An unusual solitary extramedullary plasmacytoma developed in the gingiva of a 28 year-old male renal transplant patient with cyclosporine (CyA)-induced gingival overgrowth. On initial presentation, there was no suspicion of a tumor within the lesion. One year later, however, the lesion had increased progressively in size, and its surface was ulcerated. At this time, the lesion was excised by gingivectomy, and histopathological examination revealed plasmacytoma. CyA was discontinued and the patient has been closely observed for 4 years with no recurrence of the gingival lesion.